Science.gov

Sample records for ignition engines modeling

  1. LOX/Methane Main Engine Igniter Tests and Modeling

    NASA Technical Reports Server (NTRS)

    Breisacher, Kevin J.; Ajmani, Kumund

    2008-01-01

    The LOX/methane propellant combination is being considered for the Lunar Surface Access Module ascent main engine propulsion system. The proposed switch from the hypergolic propellants used in the Apollo lunar ascent engine to LOX/methane propellants requires the development of igniters capable of highly reliable performance in a lunar surface environment. An ignition test program was conducted that used an in-house designed LOX/methane spark torch igniter. The testing occurred in Cell 21 of the Research Combustion Laboratory to utilize its altitude capability to simulate a space vacuum environment. Approximately 750 ignition test were performed to evaluate the effects of methane purity, igniter body temperature, spark energy level and frequency, mixture ratio, flowrate, and igniter geometry on the ability to obtain successful ignitions. Ignitions were obtained down to an igniter body temperature of approximately 260 R with a 10 torr back-pressure. The data obtained is also being used to anchor a CFD based igniter model.

  2. Ignition of Hydrogen Balloons by Model-Rocket-Engine Igniters.

    ERIC Educational Resources Information Center

    Hartman, Nicholas T.

    2003-01-01

    Describes an alternative method for exploding hydrogen balloons as a classroom demonstration. Uses the method of igniting the balloons via an electronic match. Includes necessary materials to conduct the demonstration and discusses potential hazards. (SOE)

  3. Multi-dimensional modeling of the application of catalytic combustion to homogeneous charge compression ignition engine

    NASA Astrophysics Data System (ADS)

    Zeng, Wen; Xie, Maozhao

    2006-12-01

    The detailed surface reaction mechanism of methane on rhodium catalyst was analyzed. Comparisons between numerical simulation and experiments showed a basic agreement. The combustion process of homogeneous charge compression ignition (HCCI) engine whose piston surface has been coated with catalyst (rhodium and platinum) was numerically investigated. A multi-dimensional model with detailed chemical kinetics was built. The effects of catalytic combustion on the ignition timing, the temperature and CO concentration fields, and HC, CO and NOx emissions of the HCCI engine were discussed. The results showed the ignition timing of the HCCI engine was advanced and the emissions of HC and CO were decreased by the catalysis.

  4. Cycle Engine Modelling Of Spark Ignition Engine Processes during Wide-Open Throttle (WOT) Engine Operation Running By Gasoline Fuel

    NASA Astrophysics Data System (ADS)

    Rahim, M. F. Abdul; Rahman, M. M.; Bakar, R. A.

    2012-09-01

    One-dimensional engine model is developed to simulate spark ignition engine processes in a 4-stroke, 4 cylinders gasoline engine. Physically, the baseline engine is inline cylinder engine with 3-valves per cylinder. Currently, the engine's mixture is formed by external mixture formation using piston-type carburettor. The model of the engine is based on one-dimensional equation of the gas exchange process, isentropic compression and expansion, progressive engine combustion process, and accounting for the heat transfer and frictional losses as well as the effect of valves overlapping. The model is tested for 2000, 3000 and 4000 rpm of engine speed and validated using experimental engine data. Results showed that the engine is able to simulate engine's combustion process and produce reasonable prediction. However, by comparing with experimental data, major discrepancy is noticeable especially on the 2000 and 4000 rpm prediction. At low and high engine speed, simulated cylinder pressures tend to under predict the measured data. Whereas the cylinder temperatures always tend to over predict the measured data at all engine speed. The most accurate prediction is obtained at medium engine speed of 3000 rpm. Appropriate wall heat transfer setup is vital for more precise calculation of cylinder pressure and temperature. More heat loss to the wall can lower cylinder temperature. On the hand, more heat converted to the useful work mean an increase in cylinder pressure. Thus, instead of wall heat transfer setup, the Wiebe combustion parameters are needed to be carefully evaluated for better results.

  5. The single-zone numerical model of homogeneous charge compression ignition engine performance

    NASA Astrophysics Data System (ADS)

    Fedyanov, E. A.; Itkis, E. M.; Kuzmin, V. N.; Shumskiy, S. N.

    2017-02-01

    The single-zone model of methane-air mixture combustion in the Homogeneous Charge Compression Ignition engine was developed. First modeling efforts resulted in the selection of the detailed kinetic reaction mechanism, most appropriate for the conditions of the HCCI process. Then, the model was completed so as to simulate the performance of the four-stroke engine and was coupled by physically reasonable adjusting functions. Validation of calculations against experimental data showed acceptable agreement.

  6. LOX/Methane Main Engine Glow Plug Igniter Tests and Modeling

    NASA Technical Reports Server (NTRS)

    Breisacher, Kevin; Ajmani, Kumud

    2009-01-01

    Ignition data for tests with a LOX/methane igniter that utilized a glow plug as the ignition source are presented. The tests were conducted in a vacuum can with thermally conditioned (cold) hardware. Data showing the effects of glow plug geometry, type, and igniter operating conditions are discussed. Comparisons between experimental results and multidimensional, transient computer models are also made.

  7. Dynamical instability of spark-ignited engines

    SciTech Connect

    Kantor, J.C.

    1984-06-15

    A simple model for spark-ignited engines is proposed in which the residual exhaust gases of a combustion event affect ignition of the subsequent charge. The model is an example of a one-dimensional, discrete, nonlinear mapping of an interval. Laminar flame correlations incorporated within models for ignition exhibit Arrhenius kinetics. Small variations of the ignition time with respect to the expansion cycle alter the work produced by each cycle, thereby altering the exhaust-gas temperature. It is shown that the mixing of hot residual gases with a fresh charge is a sufficient mechanism to produce an instability of the ignition process, resulting in oscillatory behavior. When this instability is compounded with the effects of mixture turbulence, one obtains a novel picture of the well-known phenomenon of cyclic dispersion exhibited by such engines.

  8. Effect of Hydrogen Addition on Methane HCCI Engine Ignition Timing and Emissions Using a Multi-zone Model

    NASA Astrophysics Data System (ADS)

    Wang, Zi-han; Wang, Chun-mei; Tang, Hua-xin; Zuo, Cheng-ji; Xu, Hong-ming

    2009-06-01

    Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition timing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its application, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recirculation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.

  9. Ignition process in Diesel engines

    NASA Technical Reports Server (NTRS)

    Wentzel, W

    1936-01-01

    This report analyzes the heating and vaporization process of fuel droplets in a compression-ignition engine on the basis of the theory of similitude - according to which, the period for heating and complete vaporization of the average size fuel drop is only a fraction of the actually observed ignition lag. The result is that ignition takes place in the fuel vapor air mixture rather than on the surface of the drop. The theoretical result is in accord with the experimental observations by Rothrock and Waldron. The combustion shock occurring at lower terminal compression temperature, especially in the combustion of coal-tar oil, is attributable to a simultaneous igniting of a larger fuel-vapor volume formed prior to ignition.

  10. 40 CFR 1036.620 - Alternate CO2 standards based on model year 2011 compression-ignition engines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Alternate CO2 standards based on model... HEAVY-DUTY HIGHWAY ENGINES Special Compliance Provisions § 1036.620 Alternate CO2 standards based on... compression-ignition engines to the CO2 standards of this section instead of the CO2 standards in §...

  11. Stochastic Modelling and Estimation for Cyclic Pressure Variations in Spark Ignition Engines

    NASA Astrophysics Data System (ADS)

    Roberts, J. B.; Peyton Jones, J. C.; Landsborough, K. J.

    2001-03-01

    A new method of fitting linearised, parametric stochastic models of cycle-by-cycle variations of pressure, during the combustion region of a spark ignition petrol engine, is described. The technique is based on stochastically fitting the combustion models to the covariance function of the measured pressure fluctuations, obtained by averaging over the entire ensemble of measured cycles. Comparisons, for two specific combustion models, with corresponding results obtained by deterministic fitting on a cycle-by-cycle basis, show that the new method gives a similar degree of fit, but with much improved computational efficiency. It is also demonstrated that the degree of fit to the data can be further improved by modelling the residual error between the data and the combustion models in terms of Chebyshev polynomials: the parameters in these polynomials may be determined by stochastic fitting. The technique has wider applications in the condition monitoring of rotating machinery.

  12. Spark-Ignited Diesel Engine

    DTIC Science & Technology

    1990-11-27

    compression for ignition and would allow the diesel engine to operate at the more efficient and practical compression ratio of 12 to 1. To accomplish this, an...found to provide approximately equal efficiency under most operating conditions other than high load, and to provide instant cold start at the more ...high- efficiency diesel engine. The engine would be modified to have a moderate compression ratio, no swirl, and moderate to high squish to help improve

  13. An experimental and modeling study investigating the ignition delay in a military diesel engine running hexadecane (cetane) fuel

    DOE PAGES

    Cowart, Jim S.; Fischer, Warren P.; Hamilton, Leonard J.; ...

    2013-02-01

    In an effort aimed at predicting the combustion behavior of a new fuel in a conventional diesel engine, cetane (n-hexadecane) fuel was used in a military engine across the entire speed–load operating range. The ignition delay was characterized for this fuel at each operating condition. A chemical ignition delay was also predicted across the speed–load range using a detailed chemical kinetic mechanism with a constant pressure reactor model. At each operating condition, the measured in-cylinder pressure and predicted temperature at the start of injection were applied to the detailed n-hexadecane kinetic mechanism, and the chemical ignition delay was predicted withoutmore » any kinetic mechanism calibration. The modeling results show that fuel–air parcels developed from the diesel spray with an equivalence ratio of 4 are the first to ignite. The chemical ignition delay results also showed decreasing igntion delays with increasing engine load and speed, just as the experimental data revealed. At lower engine speeds and loads, the kinetic modeling results show the characteristic two-stage negative temperature coefficient behavior of hydrocarbon fuels. However, at high engine speeds and loads, the reactions do not display negative temperature coefficient behavior, as the reactions proceed directly into high-temperature pathways due to higher temperatures and pressure at injection. A moderate difference between the total and chemical ignition delays was then characterized as a phyical delay period that scales inversely with engine speed. This physical delay time is representative of the diesel spray development time and is seen to become a minority fraction of the total igntion delay at higher engine speeds. In addition, the approach used in this study suggests that the ignition delay and thus start of combustion may be predicted with reasonable accuracy using kinetic modeling to determine the chemical igntion delay. Then, in conjunction with the physical delay

  14. An experimental and modeling study investigating the ignition delay in a military diesel engine running hexadecane (cetane) fuel

    SciTech Connect

    Cowart, Jim S.; Fischer, Warren P.; Hamilton, Leonard J.; Caton, Patrick A.; Sarathy, S. Mani; Pitz, William J.

    2013-02-01

    In an effort aimed at predicting the combustion behavior of a new fuel in a conventional diesel engine, cetane (n-hexadecane) fuel was used in a military engine across the entire speed–load operating range. The ignition delay was characterized for this fuel at each operating condition. A chemical ignition delay was also predicted across the speed–load range using a detailed chemical kinetic mechanism with a constant pressure reactor model. At each operating condition, the measured in-cylinder pressure and predicted temperature at the start of injection were applied to the detailed n-hexadecane kinetic mechanism, and the chemical ignition delay was predicted without any kinetic mechanism calibration. The modeling results show that fuel–air parcels developed from the diesel spray with an equivalence ratio of 4 are the first to ignite. The chemical ignition delay results also showed decreasing igntion delays with increasing engine load and speed, just as the experimental data revealed. At lower engine speeds and loads, the kinetic modeling results show the characteristic two-stage negative temperature coefficient behavior of hydrocarbon fuels. However, at high engine speeds and loads, the reactions do not display negative temperature coefficient behavior, as the reactions proceed directly into high-temperature pathways due to higher temperatures and pressure at injection. A moderate difference between the total and chemical ignition delays was then characterized as a phyical delay period that scales inversely with engine speed. This physical delay time is representative of the diesel spray development time and is seen to become a minority fraction of the total igntion delay at higher engine speeds. In addition, the approach used in this study suggests that the ignition delay and thus start of combustion may be predicted with reasonable accuracy using kinetic modeling to determine the chemical igntion delay. Then, in conjunction with the physical delay time

  15. Plasma Igniter for Reliable Ignition of Combustion in Rocket Engines

    NASA Technical Reports Server (NTRS)

    Martin, Adam; Eskridge, Richard

    2011-01-01

    A plasma igniter has been developed for initiating combustion in liquid-propellant rocket engines. The device propels a hot, dense plasma jet, consisting of elemental fluorine and fluorine compounds, into the combustion chamber to ignite the cold propellant mixture. The igniter consists of two coaxial, cylindrical electrodes with a cylindrical bar of solid Teflon plastic in the region between them. The outer electrode is a metal (stainless steel) tube; the inner electrode is a metal pin (mild steel, stainless steel, tungsten, or thoriated-tungsten). The Teflon bar fits snugly between the two electrodes and provides electrical insulation between them. The Teflon bar may have either a flat surface, or a concave, conical surface at the open, down-stream end of the igniter (the igniter face). The igniter would be mounted on the combustion chamber of the rocket engine, either on the injector-plate at the upstream side of the engine, or on the sidewalls of the chamber. It also might sit behind a valve that would be opened just prior to ignition, and closed just after, in order to prevent the Teflon from melting due to heating from the combustion chamber.

  16. Ignition-Spark Detector for Engine Testing

    NASA Technical Reports Server (NTRS)

    Kuhr, G.

    1985-01-01

    Optical fiber views sparks directly. In fuel or oxidizer tube, optical fiber collects light from ignition spark. Fibers also used to collect light from combustion reactions for spectrographic analysis. Useful in engine testing, detector helps determine reason for engine failure.

  17. Self-ignition of S.I. engine model fuels: A shock tube investigation at high pressure

    SciTech Connect

    Fieweger, K.; Blumenthal, R.; Adomeit, G.

    1997-06-01

    The self-ignition of several spark-ignition (SI) engine fuels (iso-octane, methanol, methyl tert-butyl ether and three different mixtures of iso-octane and n-heptane), mixed with air, was investigated experimentally under relevant engine conditions by the shock tube technique. Typical modes of the self-ignition process were registered cinematographically. For temperatures relevant to piston engine combustion, the self-ignition process always starts as an inhomogeneous, deflagrative mild ignition. This instant is defined by the ignition delay time, {tau}{sub defl}. The deflagration process in most cases is followed by a secondary explosion (DDT). This transition defines a second ignition delay time, {tau}{sub DDT}, which is a suitable approximation for the chemical ignition delay time, if the change of the thermodynamic conditions of the unburned test gas due to deflagration is taken into account. For iso-octane at p = 40 bar, a NTC (negative temperature coefficient), behavior connected with a two step (cool flame) self-ignition at low temperatures was observed. This process was very pronounced for rich and less pronounced for stoichiometric mixtures. The results of the {tau}{sub DDT} delays of the stoichiometric mixtures were shortened by the primary deflagration process in the temperature range between 800 and 1,000 K. Various mixtures of iso-octane and n-heptane were investigated. The results show a strong influence of the n-heptane fraction in the mixture, both on the ignition delay time and on the mode of self-ignition. The self-ignition of methanol and MTBE (methyl tert-butyl ether) is characterized by a very pronounced initial deflagration. For temperatures below 900 K (methanol: 800 K), no secondary explosion occurs. Taking into account the pressure increase due to deflagration, the measured delays {tau}{sub DDT} of the secondary explosion are shortened by up to one order of magnitude.

  18. Combustion-wave ignition for rocket engines

    NASA Technical Reports Server (NTRS)

    Liou, Larry C.

    1992-01-01

    The combustion wave ignition concept was experimentally studied in order to verify its suitability for application in baffled sections of a large booster engine combustion chamber. Gaseous oxygen/gaseous methane (GOX/GH4) and gaseous oxygen/gaseous hydrogen (GOX/GH2) propellant combinations were evaluated in a subscale combustion wave ignition system. The system included four element tubes capable of carrying ignition energy simultaneously to four locations, simulating four baffled sections. Also, direct ignition of a simulated Main Combustion Chamber (MCC) was performed. Tests were conducted over a range of mixture ratios and tube geometries. Ignition was consistently attained over a wide range of mixture ratios. And at every ignition, the flame propagated through all four element tubes. For GOX/GH4, the ignition system ignited the MCC flow at mixture ratios from 2 to 10 and for GOX/GH2 the ratios is from 2 to 13. The ignition timing was found to be rapid and uniform. The total ignition delay when using the MCC was under 11 ms, with the tube-to-tube, as well as the run-to-run, variation under 1 ms. Tube geometries were found to have negligible effect on the ignition outcome and timing.

  19. Multi-zone modelling of partially premixed low-temperature combustion in pilot-ignited natural-gas engines

    SciTech Connect

    Krishnan, S. R.; inivasan, K. K.

    2010-09-14

    Detailed results from a multi-zone phenomenological simulation of partially premixed advanced-injection low-pilot-ignited natural-gas low-temperature combustion are presented with a focus on early injection timings (the beginning of (pilot) injection (BOI)) and very small diesel quantities (2-3 per cent of total fuel energy). Combining several aspects of diesel and spark ignition engine combustion models, the closed-cycle simulation accounted for diesel autoignition, diesel spray combustion, and natural-gas combustion by premixed turbulent flame propagation. The cylinder contents were divided into an unburned zone, several pilot fuel zones (or 'packets') that modelled diesel evaporation and ignition, a flame zone for natural-gas combustion, and a burned zone. The simulation predicted the onset of ignition, cylinder pressures, and heat release rate profiles satisfactorily over a wide range of BOIs (20-60° before top dead centre (before TDC)) but especially well at early BOIs. Strong coupling was observed between pilot spray combustion in the packets and premixed turbulent combustion in the flame zone and, therefore, the number of ignition centres (packets) profoundly affected flame combustion. The highest local peak temperatures (greater than 2000 K) were observed in the packets, while the flame zone was much cooler (about 1650 K), indicating that pilot diesel spray combustion is probably the dominant source of engine-out emissions of nitrogen oxide (NOx). Further, the 60° before TDC BOI yielded the lowest average peak packet temperatures (about 1720 K) compared with the 20° before TDC BOI (about 2480 K) and 40° before TDC BOI (about 2700 K). These trends support experimental NOx trends, which showed the lowest NOx emissions for the 60°, 20°, and 40° before TDC BOIs in that order. Parametric studies showed that increasing the intake charge temperature, pilot quantity, and natural-gas equivalence ratio all led to higher peak

  20. Laser ignition of engines: a realistic option!

    NASA Astrophysics Data System (ADS)

    Weinrotter, M.; Srivastava, D. K.; Iskra, K.; Graf, J.; Kopecek, H.; Klausner, J.; Herdin, G.; Wintner, E.

    2006-01-01

    Due to the demands of the market to increase efficiencies and power densities of gas engines, existing ignition schemes are gradually reaching their limits. These limitations initially triggered the development of laser ignition as an effective alternative, first only for gas engines and now for a much wider range of internal combustion engines revealing a number of immediate advantages like no electrode erosion or flame kernel quenching. Furthermore and most noteworthy, already the very first engine tests about 5 years ago had resulted in a drastic reduction of NO x emissions. Within this broad range investigation, laser plasmas were generated by ns Nd-laser pulses and characterized by emission and Schlieren diagnostic methods. High-pressure chamber experiments with lean hydrogen-methane-air mixtures were successfully performed and allowed the determination of essential parameters like minimum pulse energies at different ignition pressures and temperatures as well as at variable fuel air compositions. Multipoint ignition was studied for different ignition point locations. In this way, relevant parameters were acquired allowing to estimate future laser ignition systems. Finally, a prototype diode-pumped passively Q-switched Nd:YAG laser was tested successfully at a gasoline engine allowing to monitor the essential operation characteristics. It is expected that laser ignition involving such novel solid-state lasers will allow much lower maintenance efforts.

  1. Plasma igniter for internal-combustion engines

    NASA Technical Reports Server (NTRS)

    Breshears, R. R.; Fitzgerald, D. J.

    1978-01-01

    Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

  2. Engineering the National Ignition Facility

    SciTech Connect

    Bowers, J; Hackel, R; Larson, D; Manes, K; Murray, J; Sawicki, R

    1998-08-19

    The engineering team of the National Ignition Facility (NIF) has developed a highly optimized hardware design that satisfies stringent cost, performance and schedule requirements. After a 3-year effort, the design will culminate at the end of FY98 with the completion of major Title II design reviews. Every element of the facility from optic configuration, facility layout and hardware specifications to material selection, fabrication techniques and part tolerancing has been examined to assure the minimum cost per joule of laser energy delivered on target. In this paper, the design of the major subsystems will be discussed from the perspective of this optimization emphasis. Focus will be placed on the special equipment hardware which includes laser, beam transport, opto-mechanical , system control and target area systems. Some of the unique features in each of these areas will be discussed to highlight how significant cost savings have been achieved while maintaining reasonable and acceptable performance risk. Key to the success has also been a vigorous development program that commenced nearly 4 years ago and has been highly responsive to the specific needs of the NIF project. Supporting analyses and prototyping work that evolved from these parallel activities will also be discussed.

  3. Combustion of CNG in Charged Spark Ignition Engines

    NASA Astrophysics Data System (ADS)

    Mitianiec, Wladyslaw

    2009-12-01

    The paper describes mixing of injected CNG with air and combustion process in spark ignition internal combustion engine. Because of higher ignition temperature of CNG the SI engines have more effective ignition system than conventional engines. The gas motion, turbulence, charge temperature and obviously electrical energy of the ignition coil have a big influence on the ignition and burning process in the combustion chamber. The paper includes theoretical and experimental investigations of ignition process in the high charged SI engines with direct CNG injection by using LES technique in KIVA program. Simulation of CNG combustion in the caloric chamber was carried in the environment of OpenFOAM program with LES model and also the experimental test was carried out for comparison of results in the chamber with the same geometry. The influence of the "tumble" and "swirl" on the sparking is shown by modelling of this process in premixed charge by using LES technique. The charge motion and also considerably turbulence effect influence strongly on the ignition process.

  4. PETN ignition experiments and models.

    PubMed

    Hobbs, Michael L; Wente, William B; Kaneshige, Michael J

    2010-04-29

    Ignition experiments from various sources, including our own laboratory, have been used to develop a simple ignition model for pentaerythritol tetranitrate (PETN). The experiments consist of differential thermal analysis, thermogravimetric analysis, differential scanning calorimetry, beaker tests, one-dimensional time to explosion tests, Sandia's instrumented thermal ignition tests (SITI), and thermal ignition of nonelectrical detonators. The model developed using this data consists of a one-step, first-order, pressure-independent mechanism used to predict pressure, temperature, and time to ignition for various configurations. The model was used to assess the state of the degraded PETN at the onset of ignition. We propose that cookoff violence for PETN can be correlated with the extent of reaction at the onset of ignition. This hypothesis was tested by evaluating metal deformation produced from detonators encased in copper as well as comparing postignition photos of the SITI experiments.

  5. Simultaneous dual mode combustion engine operating on spark ignition and homogenous charge compression ignition

    DOEpatents

    Fiveland, Scott B.; Wiggers, Timothy E.

    2004-06-22

    An engine particularly suited to single speed operation environments, such as stationary power generators. The engine includes a plurality of combustion cylinders operable under homogenous charge compression ignition, and at least one combustion cylinder operable on spark ignition concepts. The cylinder operable on spark ignition concepts can be convertible to operate under homogenous charge compression ignition. The engine is started using the cylinders operable under spark ignition concepts.

  6. Ignition apparatus for internal combustion engine

    SciTech Connect

    Imoto, K.; Katada, H.

    1986-10-07

    An ignition apparatus is described for an internal combustion engine having a crankshaft and a camshaft coupled to the crankshaft to be rotated thereby, comprising: crankshaft position signal generating means for detecting that the crankshaft has rotated to a predetermined angular position and for generating crankshaft position signals in response to the detection; camshaft position signal generating means for detecting that the camshaft has rotated to a predetermined angular position and for generating camshaft position signals in response to the detection; command signal generating means coupled to receive the crankshaft position signals, for generating ignition command signals in response to the crankshaft position signals; and ignition circuit means for generating a high ignition voltage in response to the ignition command signals.

  7. Propellant-Flow-Actuated Rocket Engine Igniter

    NASA Technical Reports Server (NTRS)

    Wollen, Mark

    2013-01-01

    A rocket engine igniter has been created that uses a pneumatically driven hammer that, by specialized geometry, is induced into an oscillatory state that can be used to either repeatedly impact a piezoelectric crystal with sufficient force to generate a spark capable of initiating combustion, or can be used with any other system capable of generating a spark from direct oscillatory motion. This innovation uses the energy of flowing gaseous propellant, which by means of pressure differentials and kinetic motion, causes a hammer object to oscillate. The concept works by mass flows being induced through orifices on both sides of a cylindrical tube with one or more vent paths. As the mass flow enters the chamber, the pressure differential is caused because the hammer object is supplied with flow on one side and the other side is opened with access to the vent path. The object then crosses the vent opening and begins to slow because the pressure differential across the ball reverses due to the geometry in the tube. Eventually, the object stops because of the increasing pressure differential on the object until all of the kinetic energy has been transferred to the gas via compression. This is the point where the object reverses direction because of the pressure differential. This behavior excites a piezoelectric crystal via direct impact from the hammer object. The hammer strikes a piezoelectric crystal, then reverses direction, and the resultant high voltage created from the crystal is transferred via an electrode to a spark gap in the ignition zone, thereby providing a spark to ignite the engine. Magnets, or other retention methods, might be employed to favorably position the hammer object prior to start, but are not necessary to maintain the oscillatory behavior. Various manifestations of the igniter have been developed and tested to improve device efficiency, and some improved designs are capable of operation at gas flow rates of a fraction of a gram per second (0

  8. A sustained-arc ignition system for internal combustion engines

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1977-01-01

    A sustained-arc ignition system was developed for internal combustion engines. It produces a very-long-duration ignition pulse with an energy in the order of 100 millijoules. The ignition pulse waveform can be controlled to predetermined actual ignition requirements. The design of the sustained-arc ignition system is presented in the report.

  9. Friction of Compression-ignition Engines

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Collins, John H , Jr

    1936-01-01

    The cost in mean effective pressure of generating air flow in the combustion chambers of single-cylinder compression-ignition engines was determined for the prechamber and the displaced-piston types of combustion chamber. For each type a wide range of air-flow quantities, speeds, and boost pressures was investigated. Supplementary tests were made to determine the effect of lubricating-oil temperature, cooling-water temperature, and compression ratio on the friction mean effective pressure of the single-cylinder test engine. Friction curves are included for two 9-cylinder, radial, compression-ignition aircraft engines. The results indicate that generating the optimum forced air flow increased the motoring losses approximately 5 pounds per square inch mean effective pressure regardless of chamber type or engine speed. With a given type of chamber, the rate of increase in friction mean effective pressure with engine speed is independent of the air-flow speed. The effect of boost pressure on the friction cannot be predicted because the friction was decreased, unchanged, or increased depending on the combustion-chamber type and design details. High compression ratio accounts for approximately 5 pounds per square inch mean effective pressure of the friction of these single-cylinder compression-ignition engines. The single-cylinder test engines used in this investigation had a much higher friction mean effective pressure than conventional aircraft engines or than the 9-cylinder, radial, compression-ignition engines tested so that performance should be compared on an indicated basis.

  10. Laser ignited engines: progress, challenges and prospects.

    PubMed

    Dearden, Geoff; Shenton, Tom

    2013-11-04

    Laser ignition (LI) has been shown to offer many potential benefits compared to spark ignition (SI) for improving the performance of internal combustion (IC) engines. This paper outlines progress made in recent research on laser ignited IC engines, discusses the potential advantages and control opportunities and considers the challenges faced and prospects for its future implementation. An experimental research effort has been underway at the University of Liverpool (UoL) to extend the stratified speed/load operating region of the gasoline direct injection (GDI) engine through LI research, for which an overview of some of the approaches, testing and results to date are presented. These indicate how LI can be used to improve control of the engine for: leaner operation, reductions in emissions, lower idle speed and improved combustion stability.

  11. Effects of primary breakup modeling on spray and combustion characteristics of compression ignition engines

    SciTech Connect

    Som, S.; Aggarwal, S.K.

    2010-06-15

    Injector flow dynamics and primary breakup processes are known to play a pivotal role in determining combustion and emissions in diesel engines. In the present study, we examine the effects of primary breakup modeling on the spray and combustion characteristics under diesel engine conditions. The commonly used KH model, which considers the aerodynamically induced breakup based on the Kelvin-Helmholtz instability, is modified to include the effects of cavitation and turbulence generated inside the injector. The KH model and the new (KH-ACT) model are extensively evaluated by performing 3-D time-dependent simulations with detailed chemistry under diesel engine conditions. Results indicate that the inclusion of cavitation and turbulence enhances primary breakup, leading to smaller droplet sizes, decrease in liquid penetration, and increase in the radial dispersion of spray. Predictions are compared with measurements for non-evaporating and evaporating sprays, as well as with flame measurements. While both the models are able to reproduce the experimentally observed global spray and combustion characteristics, predictions using the KH-ACT model exhibit closer agreement with measurements in terms of liquid penetration, cone angle, spray axial velocity, and liquid mass distribution for non-evaporating sprays. Similarly, the KH-ACT model leads to better agreement with respect to the liquid length and vapor penetration distance for evaporating sprays, and with respect to the flame lift-off location for combusting sprays. The improved agreement is attributed to the ability of the new model to account for the effects of turbulence and cavitation generated inside the injector, which enhance the primary breakup. Results further indicate that the combustion under diesel engine conditions is characterized by a double-flame structure with a rich premixed reaction zone near the flame stabilization region and a non-premixed reaction zone further downstream. This flame structure is

  12. Ignition of Isomers of Pentane: An Experimental and Kinetic Modeling Study

    DTIC Science & Technology

    2000-08-04

    diesel engines [26,27], and ignition under homogeneous charge compres- sion ignition ( HCCI ) conditions [26,28]. Kinetic modeling shows that the isomers of...Introduction Hydrocarbon ignition is important in many prac- tical combustion systems, including internal com- bustion engines , detonations, pulse combustors...tem- peratures are similar to those in automotive engines during diesel ignition and end-gas autoignition in spark-ignition engines . The RCM provides

  13. Fuel quantity modulation in pilot ignited engines

    DOEpatents

    May, Andrew

    2006-05-16

    An engine system includes a first fuel regulator adapted to control an amount of a first fuel supplied to the engine, a second fuel regulator adapted to control an amount of a second fuel supplied to the engine concurrently with the first fuel being supplied to the engine, and a controller coupled to at least the second fuel regulator. The controller is adapted to determine the amount of the second fuel supplied to the engine in a relationship to the amount of the first fuel supplied to the engine to operate in igniting the first fuel at a specified time in steady state engine operation and adapted to determine the amount of the second fuel supplied to the engine in a manner different from the relationship at steady state engine operation in transient engine operation.

  14. 14 CFR 23.1165 - Engine ignition systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine ignition systems. 23.1165 Section 23... Controls and Accessories § 23.1165 Engine ignition systems. (a) Each battery ignition system must be... allow continued engine operation if any battery becomes depleted. (b) The capacity of batteries and...

  15. 14 CFR 29.1165 - Engine ignition systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine ignition systems. 29.1165 Section 29... Engine ignition systems. (a) Each battery ignition system must be supplemented with a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

  16. 14 CFR 25.1165 - Engine ignition systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine ignition systems. 25.1165 Section 25... Engine ignition systems. (a) Each battery ignition system must be supplemented by a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

  17. 14 CFR 25.1165 - Engine ignition systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine ignition systems. 25.1165 Section 25... Engine ignition systems. (a) Each battery ignition system must be supplemented by a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

  18. 14 CFR 29.1165 - Engine ignition systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine ignition systems. 29.1165 Section 29... Engine ignition systems. (a) Each battery ignition system must be supplemented with a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

  19. 14 CFR 23.1165 - Engine ignition systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine ignition systems. 23.1165 Section 23... Controls and Accessories § 23.1165 Engine ignition systems. (a) Each battery ignition system must be... allow continued engine operation if any battery becomes depleted. (b) The capacity of batteries and...

  20. 14 CFR 23.1165 - Engine ignition systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine ignition systems. 23.1165 Section 23... Controls and Accessories § 23.1165 Engine ignition systems. (a) Each battery ignition system must be... allow continued engine operation if any battery becomes depleted. (b) The capacity of batteries and...

  1. 14 CFR 29.1165 - Engine ignition systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine ignition systems. 29.1165 Section 29... Engine ignition systems. (a) Each battery ignition system must be supplemented with a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

  2. 14 CFR 25.1165 - Engine ignition systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine ignition systems. 25.1165 Section 25... Engine ignition systems. (a) Each battery ignition system must be supplemented by a generator that is automatically available as an alternate source of electrical energy to allow continued engine operation if any...

  3. 14 CFR 23.1165 - Engine ignition systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Engine ignition systems. 23.1165 Section 23... Controls and Accessories § 23.1165 Engine ignition systems. (a) Each battery ignition system must be... allow continued engine operation if any battery becomes depleted. (b) The capacity of batteries and...

  4. Prechamber Compression-Ignition Engine Performance

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Collins, John H , Jr

    1938-01-01

    Single-cylinder compression-ignition engine tests were made to investigate the performance characteristics of prechamber type of cylinder head. Certain fundamental variables influencing engine performance -- clearance distribution, size, shape, and direction of the passage connecting the cylinder and prechamber, shape of prechamber, cylinder clearance, compression ratio, and boosting -- were independently tested. Results of motoring and of power tests, including several typical indicator cards, are presented.

  5. Plasma igniter for internal combustion engine

    NASA Technical Reports Server (NTRS)

    Fitzgerald, D. J.; Breshears, R. R. (Inventor)

    1978-01-01

    An igniter for the air/fuel mixture used in the cylinders of an internal combustion engine is described. A conventional spark is used to initiate the discharge of a large amount of energy stored in a capacitor. A high current discharge of the energy in the capacitor switched on by a spark discharge produces a plasma and a magnetic field. The resultant combined electromagnetic current and magnetic field force accelerates the plasma deep into the combustion chamber thereby providing an improved ignition of the air/fuel mixture in the chamber.

  6. Diesel engines vs. spark ignition gasoline engines -- Which is ``greener``?

    SciTech Connect

    Fairbanks, J.W.

    1997-12-31

    Criteria emissions, i.e., NO{sub x}, PM, CO, CO{sub 2}, and H{sub 2}, from recently manufactured automobiles, compared on the basis of what actually comes out of the engines, the diesel engine is greener than spark ignition gasoline engines and this advantage for the diesel engine increases with time. SI gasoline engines tend to get out of tune more than diesel engines and 3-way catalytic converters and oxygen sensors degrade with use. Highway measurements of NO{sub 2}, H{sub 2}, and CO revealed that for each model year, 10% of the vehicles produce 50% of the emissions and older model years emit more than recent model year vehicles. Since 1974, cars with SI gasoline engines have uncontrolled emission until the 3-way catalytic converter reaches operating temperature, which occurs after roughly 7 miles of driving. Honda reports a system to be introduced in 1998 that will alleviate this cold start problem by storing the emissions then sending them through the catalytic converter after it reaches operating temperature. Acceleration enrichment, wherein considerable excess fuel is introduced to keep temperatures down of SI gasoline engine in-cylinder components and catalytic converters so these parts meet warranty, results in 2,500 times more CO and 40 times more H{sub 2} being emitted. One cannot kill oneself, accidentally or otherwise, with CO from a diesel engine vehicle in a confined space. There are 2,850 deaths per year attributable to CO from SI gasoline engine cars. Diesel fuel has advantages compared with gasoline. Refinery emissions are lower as catalytic cracking isn`t necessary. The low volatility of diesel fuel results in a much lower probability of fires. Emissions could be improved by further reducing sulfur and aromatics and/or fuel additives. Reformulated fuel has become the term covering reducing the fuels contribution to emissions. Further PM reduction should be anticipated with reformulated diesel and gasoline fuels.

  7. Microwave-Assisted Ignition for Improved Internal Combustion Engine Efficiency

    NASA Astrophysics Data System (ADS)

    DeFilippo, Anthony Cesar

    The ever-present need for reducing greenhouse gas emissions associated with transportation motivates this investigation of a novel ignition technology for internal combustion engine applications. Advanced engines can achieve higher efficiencies and reduced emissions by operating in regimes with diluted fuel-air mixtures and higher compression ratios, but the range of stable engine operation is constrained by combustion initiation and flame propagation when dilution levels are high. An advanced ignition technology that reliably extends the operating range of internal combustion engines will aid practical implementation of the next generation of high-efficiency engines. This dissertation contributes to next-generation ignition technology advancement by experimentally analyzing a prototype technology as well as developing a numerical model for the chemical processes governing microwave-assisted ignition. The microwave-assisted spark plug under development by Imagineering, Inc. of Japan has previously been shown to expand the stable operating range of gasoline-fueled engines through plasma-assisted combustion, but the factors limiting its operation were not well characterized. The present experimental study has two main goals. The first goal is to investigate the capability of the microwave-assisted spark plug towards expanding the stable operating range of wet-ethanol-fueled engines. The stability range is investigated by examining the coefficient of variation of indicated mean effective pressure as a metric for instability, and indicated specific ethanol consumption as a metric for efficiency. The second goal is to examine the factors affecting the extent to which microwaves enhance ignition processes. The factors impacting microwave enhancement of ignition processes are individually examined, using flame development behavior as a key metric in determining microwave effectiveness. Further development of practical combustion applications implementing microwave

  8. Railplug Ignition System for Enhanced Engine Performance and Reduced Maintenance

    SciTech Connect

    DK Ezekoye; Matt Hall; Ron Matthews

    2005-08-01

    This Final Technical Report discusses the progress that was made on the experimental and numerical tasks over the duration of this project. The primary objectives of the project were to (1) develop an improved understanding of the spark ignition process, and (2) develop the railplug as an improved ignitor for large bore stationary natural gas engines. We performed fundamental experiments on the physical processes occurring during spark ignition and used the results from these experiments to aid our development of the most complete model of the spark ignition process ever devised. The elements in this model include (1) the dynamic response of the ignition circuit, (2) a chemical kinetics mechanism that is suitable for the reactions that occur in the plasma, (3) conventional flame propagation kinetics, and (4) a multi-dimensional formulation so that bulk flow through the spark gap can be incorporated. This model (i.e., a Fortran code that can be used as a subroutine within an engine modeling code such as KIVA) can be obtained from Prof. Ron Matthews at rdmatt{at}mail.utexas.edu or Prof. DK Ezekoye at dezekoye{at}mail.utexas.edu. Fundamental experiments, engine experiments, and modeling tasks were used to help develop the railplug as a new ignitor for large bore natural gas engines. As the result of these studies, we developed a railplug that could extend the Lean Stability Limit (LSL) of an engine operating at full load on natural gas from {phi} = 0.59 for operation on spark plugs down to {phi} = 0.53 using railplugs with the same delivered energy (0.7 J). However, this delivered energy would rapidly wear out the spark plug. For a conventional delivered energy (<0.05 J), the LSL is {phi} = 0.63 for a spark plug. Further, using a permanent magnet to aid the plasma movement, the LSL was extended to {phi} = 0.54 for a railplug with a delivered energy of only 0.15 J/shot, a typical discharge energy for commercial capacitive discharge ignition systems. Here, it should be

  9. Enhanced Model for Fast Ignition

    SciTech Connect

    Mason, Rodney J.

    2010-10-12

    Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

  10. Evaluating temperature and fuel stratification for heat-release rate control in a reactivity-controlled compression-ignition engine using optical diagnostics and chemical kinetics modeling

    SciTech Connect

    Musculus, Mark P. B.; Kokjohn, Sage L.; Reitz, Rolf D.

    2015-04-23

    We investigated the combustion process in a dual-fuel, reactivity-controlled compression-ignition (RCCI) engine using a combination of optical diagnostics and chemical kinetics modeling to explain the role of equivalence ratio, temperature, and fuel reactivity stratification for heat-release rate control. An optically accessible engine is operated in the RCCI combustion mode using gasoline primary reference fuels (PRF). A well-mixed charge of iso-octane (PRF = 100) is created by injecting fuel into the engine cylinder during the intake stroke using a gasoline-type direct injector. Later in the cycle, n-heptane (PRF = 0) is delivered through a centrally mounted diesel-type common-rail injector. This injection strategy generates stratification in equivalence ratio, fuel blend, and temperature. The first part of this study uses a high-speed camera to image the injection events and record high-temperature combustion chemiluminescence. Moreover, the chemiluminescence imaging showed that, at the operating condition studied in the present work, mixtures in the squish region ignite first, and the reaction zone proceeds inward toward the center of the combustion chamber. The second part of this study investigates the charge preparation of the RCCI strategy using planar laser-induced fluorescence (PLIF) of a fuel tracer under non-reacting conditions to quantify fuel concentration distributions prior to ignition. The fuel-tracer PLIF data show that the combustion event proceeds down gradients in the n-heptane distribution. The third part of the study uses chemical kinetics modeling over a range of mixtures spanning the distributions observed from the fuel-tracer fluorescence imaging to isolate the roles of temperature, equivalence ratio, and PRF number stratification. The simulations predict that PRF number stratification is the dominant factor controlling the ignition location and growth rate of the reaction zone. Equivalence ratio has a smaller, but still significant

  11. Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

    NASA Technical Reports Server (NTRS)

    Thomas, Matt; Bossard, John; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

    2001-01-01

    This viewgraph presentation gives an overview of laser ignition technology for bipropellant rocket engines applications. The objectives of this project include: (1) the selection test chambers and flows; (2) definition of the laser ignition setup; (3) pulse format optimization; (4) fiber optic coupled laser ignition system analysis; and (5) chamber integration issues definition. The testing concludes that rocket combustion chamber laser ignition is imminent. Support technologies (multiplexing, window durability/cleaning, and fiber optic durability) are feasible.

  12. Low emissions compression ignited engine technology

    DOEpatents

    Coleman, Gerald N.; Kilkenny, Jonathan P.; Fluga, Eric C.; Duffy, Kevin P.

    2007-04-03

    A method and apparatus for operating a compression ignition engine having a cylinder wall, a piston, and a head defining a combustion chamber. The method and apparatus includes delivering fuel substantially uniformly into the combustion chamber, the fuel being dispersed throughout the combustion chamber and spaced from the cylinder wall, delivering an oxidant into the combustion chamber sufficient to support combustion at a first predetermined combustion duration, and delivering a diluent into the combustion chamber sufficient to change the first predetermined combustion duration to a second predetermined combustion duration different from the first predetermined combustion duration.

  13. Probability density function treatment of turbulence/chemistry interactions during the ignition of a temperature-stratified mixture for application to HCCI engine modeling

    SciTech Connect

    Bisetti, Fabrizio; Chen, J.-Y.; Hawkes, Evatt R.; Chen, Jacqueline H.

    2008-12-15

    Homogeneous charge compression ignition (HCCI) engine technology promises to reduce NO{sub x} and soot emissions while achieving high thermal efficiency. Temperature and mixture stratification are regarded as effective means of controlling the start of combustion and reducing the abrupt pressure rise at high loads. Probability density function methods are currently being pursued as a viable approach to modeling the effects of turbulent mixing and mixture stratification on HCCI ignition. In this paper we present an assessment of the merits of three widely used mixing models in reproducing the moments of reactive scalars during the ignition of a lean hydrogen/air mixture ({phi}=0.1, p=41atm, and T=1070 K) under increasing temperature stratification and subject to decaying turbulence. The results from the solution of the evolution equation for a spatially homogeneous joint PDF of the reactive scalars are compared with available direct numerical simulation (DNS) data [E.R. Hawkes, R. Sankaran, P.P. Pebay, J.H. Chen, Combust. Flame 145 (1-2) (2006) 145-159]. The mixing models are found able to quantitatively reproduce the time history of the heat release rate, first and second moments of temperature, and hydroxyl radical mass fraction from the DNS results. Most importantly, the dependence of the heat release rate on the extent of the initial temperature stratification in the charge is also well captured. (author)

  14. Laser-induced ignition of gasoline direct-injection engines

    NASA Astrophysics Data System (ADS)

    Liedl, Gerhard; Schuoecker, Dieter; Geringer, B.; Graf, J.; Klawatsch, D.; Lenz, H. P.; Piock, W. F.; Jetzinger, M.; Kapus, P.

    2005-03-01

    A q-switched Nd:YAG laser as well as an excimer laser with an unstable resonator have been used for ignition of combustion processes. Following first experiments with a combustion bomb a gasoline direct injection engine has been modified for laser ignition by installation of a focusing element and a beam entrance window. It was possible with the q-switched Nd:YAG laser which delivers short pulses with a duration of lesss than 6 ns to ignite the engine for several 100 hours without problems. Compared to conventional spark ignition, laser ignition allows a more flexible choice of the ignition location inside the combustion chamber with the possibility to ignite even inside the fuel spray. Measurements of fuel consumption and emissions prove that laser ignition has important advantages compared to conventional spark ignition systems. Experiments with the direct injection engine have been carried out at the fundamental wavelength of the Nd:YAG laser as well as with a frequency doubled system. No differences in the minimal pulse energy needed for ignition could be found, since the minimal pulse energy for ignition is mainly determined by the ablation thresholds of combustion deposits at the surface of the window to the combustion chamber. Such combustion deposits reduce the transparency of the window where the laser beam enters the combustion chamber and a "self-cleaning" mechanism of the window by ablation is essential for successful operation. Experiments show that above a certain threshold intensity of the laser beam at the window even highly polluted surfaces could be cleaned with teh first laser pulse which is important for operation in real-world engines. Theoretically calculated energy values for laser ignition are much lower since such mechanisms are usually not considered. Power and space requirements on possible future development of laser ignition systems are discussed briefly. Several concepts for laser ignition, like diode-pumped solid state lasers (DPSS

  15. Ignition study of a petrol/CNG single cylinder engine

    NASA Astrophysics Data System (ADS)

    Khan, N.; Saleem, Z.; Mirza, A. A.

    2005-11-01

    Benefits of laser ignition over the electrical ignition system for Compressed Natural Gas (CNG) engines have fuelled automobile industry and led to an extensive research on basic characteristics to switch over to the emerging technologies. This study was undertaken to determine the electrical and physical characteristics of the electric spark ignition of single cylinder petrol/CNG engine to determine minimum ignition requirements and timeline of ignition events to use in subsequent laser ignition study. This communication briefly reviews the ongoing research activities and reports the results of this experimental study. The premixed petrol and CNG mixtures were tested for variation of current and voltage characteristics of the spark with speed of engine. The current magnitude of discharge circuit was found to vary linearly over a wide range of speed but the stroke to stroke fire time was found to vary nonlinearly. The DC voltage profiles were observed to fluctuate randomly during ignition process and staying constant in rest of the combustion cycle. Fire to fire peaks of current amplitudes fluctuated up to 10% of the peak values at constant speed but increased almost linearly with increase in speed. Technical barriers of laser ignition related to threshold minimum ignition energy, inter-pulse durations and firing sequence are discussed. Present findings provide a basic initiative and background information for designing suitable timeline algorithms for laser ignited leaner direct injected CNG engines.

  16. Distributed ignition method and apparatus for a combustion engine

    SciTech Connect

    Willi, Martin L.; Bailey, Brett M.; Fiveland, Scott B.; Gong, Weidong

    2006-03-07

    A method and apparatus for operating an internal combustion engine is provided. The method comprises the steps of introducing a primary fuel into a main combustion chamber of the engine, introducing a pilot fuel into the main combustion chamber of the engine, determining an operating load of the engine, determining a desired spark plug ignition timing based on the engine operating load, and igniting the primary fuel and pilot fuel with a spark plug at the desired spark plug ignition timing. The method is characterized in that the octane number of the pilot fuel is lower than the octane number of the primary fuel.

  17. RAILPLUG IGNITION SYSTEM FOR ENHANCED ENGINE PERFORMANCE AND REDUCED MAINTENANCE

    SciTech Connect

    Ron Matthews

    2003-09-19

    During the first 18 months of this project, four experimental subtasks were to have begun but only one of these was to have been completed. Additionally, five modeling subtasks were scheduled to begin, four of which were to have been completed. We are on schedule for all but one of these subtasks. All four experimental tasks are progressing on schedule. Initial durability tests were completed. The conclusions drawn from this first round of durability tests are being used to design the next set of tests. Initial baseline engine data were acquired and showed that the engine selected for this task behaves as hoped. However, the dyno controller is inadequate. The engine will be moved to another dyno during the near future. The modeling tasks are also progressing well. A model for the dynamic response of the ignition circuit was developed and validated. Two technical papers resulting from this model were submitted for publication. Development of a model for the railplug ignition process was begun but was not scheduled for completion. Progress on this task consisted of two subtasks. First, a railplug circuit model was also developed and validated. Second, a model was developed for the physics that govern railplug performance. This initial model incorporated only the effects of the Lorentz force on arc movement. From this model, it is concluded that thermal expansion is important to the performance of railplugs. Thermal expansion, and other physical effects, will be added to the model in the near future. We delayed the development of a 3D model for the ignition process, until near the end of the project because of the computational time requirements. We can learn most of the important lessons from the 2D model. Delay of this subtask will not affect the timely completion of the project.

  18. Ignition and combustion phenomena in Diesel engines

    NASA Technical Reports Server (NTRS)

    Sass, F

    1928-01-01

    Evidences were found that neither gasification nor vaporization of the injected fuel occurs before ignition; also that the hydrogen coefficient has no significance. However the knowledge of the ignition point and of the "time lag" is important. After ignition, the combustion proceeds in a series of reactions, the last of which at least are now known.

  19. Variable valve timing in a homogenous charge compression ignition engine

    DOEpatents

    Lawrence, Keith E.; Faletti, James J.; Funke, Steven J.; Maloney, Ronald P.

    2004-08-03

    The present invention relates generally to the field of homogenous charge compression ignition engines, in which fuel is injected when the cylinder piston is relatively close to the bottom dead center position for its compression stroke. The fuel mixes with air in the cylinder during the compression stroke to create a relatively lean homogeneous mixture that preferably ignites when the piston is relatively close to the top dead center position. However, if the ignition event occurs either earlier or later than desired, lowered performance, engine misfire, or even engine damage, can result. The present invention utilizes internal exhaust gas recirculation and/or compression ratio control to control the timing of ignition events and combustion duration in homogeneous charge compression ignition engines. Thus, at least one electro-hydraulic assist actuator is provided that is capable of mechanically engaging at least one cam actuated intake and/or exhaust valve.

  20. Evaluating temperature and fuel stratification for heat-release rate control in a reactivity-controlled compression-ignition engine using optical diagnostics and chemical kinetics modeling

    DOE PAGES

    Musculus, Mark P. B.; Kokjohn, Sage L.; Reitz, Rolf D.

    2015-04-23

    We investigated the combustion process in a dual-fuel, reactivity-controlled compression-ignition (RCCI) engine using a combination of optical diagnostics and chemical kinetics modeling to explain the role of equivalence ratio, temperature, and fuel reactivity stratification for heat-release rate control. An optically accessible engine is operated in the RCCI combustion mode using gasoline primary reference fuels (PRF). A well-mixed charge of iso-octane (PRF = 100) is created by injecting fuel into the engine cylinder during the intake stroke using a gasoline-type direct injector. Later in the cycle, n-heptane (PRF = 0) is delivered through a centrally mounted diesel-type common-rail injector. This injectionmore » strategy generates stratification in equivalence ratio, fuel blend, and temperature. The first part of this study uses a high-speed camera to image the injection events and record high-temperature combustion chemiluminescence. Moreover, the chemiluminescence imaging showed that, at the operating condition studied in the present work, mixtures in the squish region ignite first, and the reaction zone proceeds inward toward the center of the combustion chamber. The second part of this study investigates the charge preparation of the RCCI strategy using planar laser-induced fluorescence (PLIF) of a fuel tracer under non-reacting conditions to quantify fuel concentration distributions prior to ignition. The fuel-tracer PLIF data show that the combustion event proceeds down gradients in the n-heptane distribution. The third part of the study uses chemical kinetics modeling over a range of mixtures spanning the distributions observed from the fuel-tracer fluorescence imaging to isolate the roles of temperature, equivalence ratio, and PRF number stratification. The simulations predict that PRF number stratification is the dominant factor controlling the ignition location and growth rate of the reaction zone. Equivalence ratio has a smaller, but still

  1. Exhaust gas recirculation in a homogeneous charge compression ignition engine

    DOEpatents

    Duffy, Kevin P [Metamora, IL; Kieser, Andrew J [Morton, IL; Rodman, Anthony [Chillicothe, IL; Liechty, Michael P [Chillicothe, IL; Hergart, Carl-Anders [Peoria, IL; Hardy, William L [Peoria, IL

    2008-05-27

    A homogeneous charge compression ignition engine operates by injecting liquid fuel directly in a combustion chamber, and mixing the fuel with recirculated exhaust and fresh air through an auto ignition condition of the fuel. The engine includes at least one turbocharger for extracting energy from the engine exhaust and using that energy to boost intake pressure of recirculated exhaust gas and fresh air. Elevated proportions of exhaust gas recirculated to the engine are attained by throttling the fresh air inlet supply. These elevated exhaust gas recirculation rates allow the HCCI engine to be operated at higher speeds and loads rendering the HCCI engine a more viable alternative to a conventional diesel engine.

  2. Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition

    SciTech Connect

    Azer Yalin; Bryan Willson

    2008-06-30

    Past research has shown that laser ignition provides a potential means to reduce emissions and improve engine efficiency of gas-fired engines to meet longer-term DOE ARES (Advanced Reciprocating Engine Systems) targets. Despite the potential advantages of laser ignition, the technology is not seeing practical or commercial use. A major impediment in this regard has been the 'open-path' beam delivery used in much of the past research. This mode of delivery is not considered industrially practical owing to safety factors, as well as susceptibility to vibrations, thermal effects etc. The overall goal of our project has been to develop technologies and approaches for practical laser ignition systems. To this end, we are pursuing fiber optically coupled laser ignition system and multiplexing methods for multiple cylinder engine operation. This report summarizes our progress in this regard. A partial summary of our progress includes: development of a figure of merit to guide fiber selection, identification of hollow-core fibers as a potential means of fiber delivery, demonstration of bench-top sparking through hollow-core fibers, single-cylinder engine operation with fiber delivered laser ignition, demonstration of bench-top multiplexing, dual-cylinder engine operation via multiplexed fiber delivered laser ignition, and sparking with fiber lasers. To the best of our knowledge, each of these accomplishments was a first.

  3. Laser ignition in internal-combustion engines: Sparkless initiation

    NASA Astrophysics Data System (ADS)

    Andronov, A. A.; Gurin, V. A.; Marugin, A. V.; Savikin, A. P.; Svyatoshenko, D. E.; Tukhomirov, A. N.; Utkin, Yu. S.; Khimich, V. L.

    2014-08-01

    Laser ignition has been implemented in a single-cylinder internal combustion engine fueled by gasoline. Indicator diagrams (cylinder pressure versus crank angle) were obtained for laser ignition with nano- and microsecond pulses of an Nd:YAG laser. The maximum power of microsecond pulses was below critical for spark initiation, while the radiation wavelength was outside the spectral range of optical absorption by hydrocarbon fuels. Apparently, the ignition starts due to radiation absorption by the oil residues or carbon deposit in the combustion chamber, so that the ability of engine to operate is retained. This initiation of spark-free ignition shows the possibility of using compact semiconductor quantum-cascade lasers operating at wavelengths of about 3.4 μm (for which the optical absorption by fuel mixtures is high) in ignition systems of internal combustion engines.

  4. 14 CFR 23.1165 - Engine ignition systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Engine ignition systems. 23.1165 Section 23..., December 2, 2011. (a) Each battery ignition system must be supplemented by a generator that is... battery becomes depleted. (b) The capacity of batteries and generators must be large enough to meet the...

  5. Modelling piloted ignition of wood and plastics

    SciTech Connect

    Blijderveen, Maarten van; Bramer, Eddy A.; Brem, Gerrit

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We model piloted ignition times of wood and plastics. Black-Right-Pointing-Pointer The model is applied on a packed bed. Black-Right-Pointing-Pointer When the air flow is above a critical level, no ignition can take place. - Abstract: To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The incoming radiative heat flux, sample thickness and moisture content are some of the used variables. Not only the ignition time can be calculated with the model, but also the mass flux and surface temperature at ignition. The ignition times for softwoods and PMMA are mainly under-predicted. For hardwoods and PVC the predicted ignition times agree well with experimental results. Due to a significant scatter in the experimental data the mass flux and surface temperature calculated with the model are hard to validate. The model is applied on the startup of a municipal waste incineration plant. For this process a maximum allowable primary air flow is derived. When the primary air flow is above this maximum air flow, no ignition can be obtained.

  6. CORONA DISCHARGE IGNITION FOR ADVANCED STATIONARY NATURAL GAS ENGINES

    SciTech Connect

    Dr. Paul D. Ronney

    2003-09-12

    An ignition source was constructed that is capable of producing a pulsed corona discharge for the purpose of igniting mixtures in a test chamber. This corona generator is adaptable for use as the ignition source for one cylinder on a test engine. The first tests were performed in a cylindrical shaped chamber to study the characteristics of the corona and analyze various electrode geometries. Next a test chamber was constructed that closely represented the dimensions of the combustion chamber of the test engine at USC. Combustion tests were performed in this chamber and various electrode diameters and geometries were tested. The data acquisition and control system hardware for the USC engine lab was updated with new equipment. New software was also developed to perform the engine control and data acquisition functions. Work is underway to design a corona electrode that will fit in the new test engine and be capable igniting the mixture in one cylinder at first and eventually in all four cylinders. A test engine was purchased for the project that has two spark plug ports per cylinder. With this configuration it will be possible to switch between corona ignition and conventional spark plug ignition without making any mechanical modifications.

  7. Hydrogen as an Auxiliary Fuel in Compression-Ignition Engines

    NASA Technical Reports Server (NTRS)

    Gerrish, Harold C; Foster, H

    1936-01-01

    An investigation was made to determine whether a sufficient amount of hydrogen could be efficiently burned in a compression-ignition engine to compensate for the increase of lift of an airship due to the consumption of the fuel oil. The performance of a single-cylinder four-stroke-cycle compression-ignition engine operating on fuel oil alone was compared with its performance when various quantities of hydrogen were inducted with the inlet air. Engine-performance data, indicator cards, and exhaust-gas samples were obtained for each change in engine-operating conditions.

  8. Control of Ignition and Combustion of Dimethyl Ether in Homogeneous Charge Compression Ignition Engine

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Oh; Azetsu, Akihiko; Oikawa, Chikashi

    A homogeneous charge compression ignition (HCCI) engine is known to have high thermal efficiency and low nitrogen oxide emission. However, the control of ignition timing and its combustion period over a wide range of engine speeds and loads is one of the barriers to the realization of the engine. On the lean side of the equivalence ratio, control of ignition is difficult due to its long delay of ignition, and there is knocklike problem under high load. In both computations and experiments of HCCI engine operated on dimethyl ether, the operable range (the possible range of fuel input from just ignitable to knock-occurring state) shifted to the rich side with decreasing intake temperature and amount of mixing of carbon dioxide. The range of fuel input was reduced at low intake temperatures, because the hot flame onset angle advanced more quickly than it did at high intake temperatures. However, the mixing of CO2 caused the operable range to shift to the rich side while retaining the same range. The results of this study indicated the possibility of high-load operation or extension of the load range by exhaust gas recirculation.

  9. Researches on Preliminary Chemical Reactions in Spark-Ignition Engines

    NASA Technical Reports Server (NTRS)

    Muehlner, E.

    1943-01-01

    Chemical reactions can demonstrably occur in a fuel-air mixture compressed in the working cylinder of an Otto-cycle (spark ignition) internal-combustion engine even before the charge is ignited by the flame proceeding from the sparking plug. These are the so-called "prelinminary reactions" ("pre-flame" combustion or oxidation), and an exact knowledge of their characteristic development is of great importance for a correct appreciation of the phenomena of engine-knock (detonation), and consequently for its avoidance. Such reactions can be studied either in a working engine cylinder or in a combustion bomb. The first method necessitates a complicated experimental technique, while the second has the disadvantage of enabling only a single reaction to be studied at one time. Consequently, a new series of experiments was inaugurated, conducted in a motored (externally-driven) experimental engine of mixture-compression type, without ignition, the resulting preliminary reactions being detectable and measurable thermometrically.

  10. Fuel economy in road vehicles powered by spark ignition engines

    SciTech Connect

    Hilliard, J.C.; Springer, G.S.

    1984-01-01

    This book presents information on the following: automotive fuel economy; fuel economy and emissions; spark ignition physics and its effect on the internal combustion process; the effects of valve events on engine operation; flame propagation and heat-transfer effects in spark ignition engines; abnormal combustion effects on economy; mechanical friction and lubrication in automobiles; the rolling resistance and vehicle fuel economy; properties of sheet molding compounds; aerodynamics of road vehicles; power-train matching and fuel economy projection methods; and electronic engine control.

  11. Ignition points and combustion reactions in Diesel engines. Part I

    NASA Technical Reports Server (NTRS)

    Tausz, J; Schulte, F

    1928-01-01

    The question of whether the fuel should be adapted to the engine or whether it is possible to improve equipment such as carburetors and engines so that as much of the crude oil as possible may be used without further transformation is examined in this report. Various ignition points and fuel mixtures are investigated in this regard.

  12. 14 CFR 29.1165 - Engine ignition systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... that draw from the same source. (c) The design of the engine ignition system must account for— (1) The..., to minimize the probability of the simultaneous failure of two or more wires as a result of mechanical damage, electrical fault, or other cause. (e) No ground wire for any engine may be routed through...

  13. 14 CFR 29.1165 - Engine ignition systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... that draw from the same source. (c) The design of the engine ignition system must account for— (1) The..., to minimize the probability of the simultaneous failure of two or more wires as a result of mechanical damage, electrical fault, or other cause. (e) No ground wire for any engine may be routed through...

  14. A Comparison of Several Methods of Measuring Ignition Lag in a Compression-ignition Engine

    NASA Technical Reports Server (NTRS)

    Spanogle, J A

    1934-01-01

    The ignition lag of a fuel oil in the combustion chamber of a high speed compression-ignition engine was measured by three different methods. The start of injection of the fuel as observed with a Stoborama was taken as the start of the period of ignition lag in all cases. The end of the period of ignition lag was determined by observation of the appearance of incandescence in the combustion chamber, by inspection of a pressure-time card for evidence of pressure rise, and by analysis of the indicator card for evidence of the combustion of a small but definite quantity of fuel. A comparison of the values for ignition lags obtained by these three methods indicates that the appearance of incandescence is later than other evidences of the start of combustion, that visual inspection of a pressure-time diagram gives consistent and usable values with a minimum requirement of time and/or apparatus, and that analysis of the indicator card is not worth while for ignition lag alone.

  15. Influence of several factors on ignition lag in a compression-ignition engine

    NASA Technical Reports Server (NTRS)

    Gerrish, Harold C; Voss, Fred

    1932-01-01

    This investigation was made to determine the influence of fuel quality, injection advance angle, injection valve-opening pressure, inlet-air pressure, compression ratio, and engine speed on the time lag of auto-ignition of a Diesel fuel oil in a single-cylinder compression-ignition engine as obtained from an analysis of indicator diagrams. Three cam-operated fuel-injection pumps, two pumps cams, and an automatic injection valve with two different nozzles were used. Ignition lag was considered to be the interval between the start of injection of the fuel as determined with a Stroborama and the start of effective combustion as determined from the indicator diagram, the latter being the point where 4.0 x 10(exp-6) pound of fuel had been effectively burned. For this particular engine and fuel it was found that: (1) for a constant start and the same rate of fuel injection up the point of cut-off, a variation in fuel quantity from 1.2 x 10(exp-4) to 4.1 x 10(exp-4) pound per cycle has no appreciable effect on the ignition lag; (2) injection advance angle increases or decreases the lag according to whether density, temperature, or turbulence has the controlling influence; (3) increase in valve-opening pressure slightly increases the lag; and (4) increase of inlet-air pressure, compression ratio, and engine speed reduces the lag.

  16. A Study on Homogeneous Charge Compression Ignition Gasoline Engines

    NASA Astrophysics Data System (ADS)

    Kaneko, Makoto; Morikawa, Koji; Itoh, Jin; Saishu, Youhei

    A new engine concept consisting of HCCI combustion for low and midrange loads and spark ignition combustion for high loads was introduced. The timing of the intake valve closing was adjusted to alter the negative valve overlap and effective compression ratio to provide suitable HCCI conditions. The effect of mixture formation on auto-ignition was also investigated using a direct injection engine. As a result, HCCI combustion was achieved with a relatively low compression ratio when the intake air was heated by internal EGR. The resulting combustion was at a high thermal efficiency, comparable to that of modern diesel engines, and produced almost no NOx emissions or smoke. The mixture stratification increased the local A/F concentration, resulting in higher reactivity. A wide range of combustible A/F ratios was used to control the compression ignition timing. Photographs showed that the flame filled the entire chamber during combustion, reducing both emissions and fuel consumption.

  17. Hydrogen-fueled diesel engine without timed ignition

    NASA Technical Reports Server (NTRS)

    Homan, H. S.; De Boer, P. C. T.; Mclean, W. J.; Reynolds, R. K.

    1979-01-01

    Experiments were carried out to investigate the feasibility of converting a diesel engine to hydrogen-fueled operation without providing a timed ignition system. Use was made of a glow plug and a multiple-strike spark plug. The glow plug was found to provide reliable ignition and smooth engine operation. It caused the hydrogen to ignite almost immediately upon the start of injection. Indicated mean effective pressures were on the order of 1.3 MPa for equivalence ratios between 0.1 and 0.4 at a compression ratio of 18. This is significantly higher than the corresponding result obtained with diesel oil (about 0.6 MPa for equivalence ratios between 0.3 and 0.9). Indicated thermal efficiencies were on the order of 0.4 for hydrogen and 0.20-0.25 for diesel oil. Operation with the multiple-strike spark system yielded similar values for IMEP and efficiency, but gave rise to large cycle-to-cycle variations in the delay between the beginning of injection and ignition. Large ignition delays were associated with large amplitude pressure waves in the combustion chamber. The measured NO(x) concentrations in the exhaust gas were of the order of 50-100 ppm. This is significantly higher than the corresponding results obtained with premixed hydrogen and air at low equivalence ratios. Compression ignition could not be achieved even at a compression ratio of 29.

  18. Controlling And Operating Homogeneous Charge Compression Ignition (Hcci) Engines

    DOEpatents

    Flowers, Daniel L.

    2005-08-02

    A Homogeneous Charge Compression Ignition (HCCI) engine system includes an engine that produces exhaust gas. A vaporization means vaporizes fuel for the engine an air induction means provides air for the engine. An exhaust gas recirculation means recirculates the exhaust gas. A blending means blends the vaporized fuel, the exhaust gas, and the air. An induction means inducts the blended vaporized fuel, exhaust gas, and air into the engine. A control means controls the blending of the vaporized fuel, the exhaust gas, and the air and for controls the inducting the blended vaporized fuel, exhaust gas, and air into the engine.

  19. Transient Plasma Ignition for Small Internal Combustion Engines

    DTIC Science & Technology

    2013-02-01

    engines having large combustion chamber surface area to volume ratios. Piston and cylinder head design, intake manifold flow straighteners, and...Combustion Engines FA9550-10-1-0554 Dr. Martin A. Gundersen Dr. Paul Ronney University of Southern California Department of Contracts & Grants 3720 S...focused on introducing transient plasma ignition (TPI) into a small combustion engine (2 hp Fuji Imvac BF-34EI), seeking to demonstrate improved

  20. Turbulent flame propagation and combustion in spark ignition engines

    NASA Technical Reports Server (NTRS)

    Beretta, G. P.; Rashidi, M.; Keck, J. C.

    1983-01-01

    Pressure measurements synchronized with high-speed motion-picture records of flame propagation have been made in a transparent-piston engine. The data show that the initial expansion speed of the flame front is close to that of a laminar flame. As the flame expands, its speed rapidly accelerates to a quasi-steady value comparable with that of the turbulent velocity fluctuations in the unburned gas. During the quasi-steady propagation phase, a significant fraction of the gas behind the visible front is unburned. Final burnout of the charge may be approximated by an exponential decay in time. The data have been analyzed in a model-independent way to obtain a set of empirical equations for calculating mass burning rates in spark-ignition engines. The burning equations contain three parameters: the laminar burning speed, a characteristic speed (uT), and a characteristic length (lT). The laminar burning speed is known from laboratory measurements. Tentative correlations relating uT and lT to engine geometry and operating variables have been derived from the engine data.

  1. Turbulent flame propagation and combustion in spark ignition engines

    NASA Technical Reports Server (NTRS)

    Beretta, G. P.; Rashidi, M.; Keck, J. C.

    1983-01-01

    Pressure measurements synchronized with high-speed motion-picture records of flame propagation have been made in a transparent-piston engine. The data show that the initial expansion speed of the flame front is close to that of a laminar flame. As the flame expands, its speed rapidly accelerates to a quasi-steady value comparable with that of the turbulent velocity fluctuations in the unburned gas. During the quasi-steady propagation phase, a significant fraction of the gas behind the visible front is unburned. Final burnout of the charge may be approximated by an exponential decay in time. The data have been analyzed in a model-independent way to obtain a set of empirical equations for calculating mass burning rates in spark-ignition engines. The burning equations contain three parameters: the laminar burning speed, a characteristic speed (uT), and a characteristic length (lT). The laminar burning speed is known from laboratory measurements. Tentative correlations relating uT and lT to engine geometry and operating variables have been derived from the engine data.

  2. Fundamental Interactions in Gasoline Compression Ignition Engines with Fuel Stratification

    NASA Astrophysics Data System (ADS)

    Wolk, Benjamin Matthew

    Transportation accounted for 28% of the total U.S. energy demand in 2011, with 93% of U.S. transportation energy coming from petroleum. The large impact of the transportation sector on global climate change necessitates more-efficient, cleaner-burning internal combustion engine operating strategies. One such strategy that has received substantial research attention in the last decade is Homogeneous Charge Compression Ignition (HCCI). Although the efficiency and emissions benefits of HCCI are well established, practical limits on the operating range of HCCI engines have inhibited their application in consumer vehicles. One such limit is at high load, where the pressure rise rate in the combustion chamber becomes excessively large. Fuel stratification is a potential strategy for reducing the maximum pressure rise rate in HCCI engines. The aim is to introduce reactivity gradients through fuel stratification to promote sequential auto-ignition rather than a bulk-ignition, as in the homogeneous case. A gasoline-fueled compression ignition engine with fuel stratification is termed a Gasoline Compression Ignition (GCI) engine. Although a reasonable amount of experimental research has been performed for fuel stratification in GCI engines, a clear understanding of how the fundamental in-cylinder processes of fuel spray evaporation, mixing, and heat release contribute to the observed phenomena is lacking. Of particular interest is gasoline's pressure sensitive low-temperature chemistry and how it impacts the sequential auto-ignition of the stratified charge. In order to computationally study GCI with fuel stratification using three-dimensional computational fluid dynamics (CFD) and chemical kinetics, two reduced mechanisms have been developed. The reduced mechanisms were developed from a large, detailed mechanism with about 1400 species for a 4-component gasoline surrogate. The two versions of the reduced mechanism developed in this work are: (1) a 96-species version and (2

  3. Combustion in Homogeneous Charge Compression Ignition Engines: Experiments and Detailed Chemical Kinetic Simulations

    SciTech Connect

    Flowers, Daniel L.

    2002-06-07

    Homogeneous charge compression ignition (HCCI) engines are being considered as an alternative to diesel engines. The HCCI concept involves premixing fuel and air prior to induction into the cylinder (as is done in current spark-ignition engine) then igniting the fuel-air mixture through the compression process (as is done in current diesel engines). The combustion occurring in an HCCI engine is fundamentally different from a spark-ignition or Diesel engine in that the heat release occurs as a global autoignition process, as opposed to the turbulent flame propagation or mixing controlled combustion used in current engines. The advantage of this global autoignition is that the temperatures within the cylinder are uniformly low, yielding very low emissions of oxides of nitrogen (NOx, the chief precursors to photochemical smog). The inherent features of HCCI combustion allows for design of engines with efficiency comparable to, or potentially higher than, diesel engines. While HCCI engines have great potential, several technical barriers exist which currently prevent widespread commercialization of this technology. The most significant challenge is that the combustion timing cannot be controlled by typical in-cylinder means. Means of controlling combustion have been demonstrated, but a robust control methodology that is applicable to the entire range of operation has yet to be developed. This research focuses on understanding basic characteristics of controlling and operating HCCI engines. Experiments and detailed chemical kinetic simulations have been applied to the characterize some of the fundamental operational and design characteristics of HCCI engines. Experiments have been conducted on single and multi-cylinder engines to investigate general features of how combustion timing affects the performance and emissions of HCCI engines. Single-zone modeling has been used to characterize and compare the implementation of different control strategies. Multi

  4. Development of Augmented Spark Impinging Igniter System for Methane Engines

    NASA Technical Reports Server (NTRS)

    Marshall, William M.; Osborne, Robin J.; Greene, Sandra E.

    2017-01-01

    The Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) program is establishing multiple no-funds-exchanged Space Act Agreement (SAA) partnerships with U.S. private sector entities. The purpose of this program is to encourage the development of robotic lunar landers that can be integrated with U.S. commercial launch capabilities to deliver payloads to the lunar surface. As part of the efforts in Lander Technologies, NASA Marshall Space Flight Center (MSFC) is developing liquid oxygen (LOX) and liquid methane (LCH4) engine technology to share with the Lunar CATALYST partners. Liquid oxygen and liquid methane propellants are attractive owing to their relatively high specific impulse for chemical propulsion systems, modest storage requirements, and adaptability to NASA's Journey to Mars plans. Methane has also been viewed as a possible propellant choice for lunar missions, owing to the performance benefits and as a technology development stepping stone to Martian missions. However, in the development of methane propulsion, methane ignition has historically been viewed as a high risk area in the development of such an engine. A great deal of work has been conducted in the past decade devoted to risk reduction in LOX/CH4 ignition. This paper will review and summarize the history and results of LOX/CH4 ignition programs conducted at NASA. More recently, a NASA-developed Augmented Spark Impinging (ASI) igniter body, which utilizes a conventional spark exciter system, is being tested with LOX/CH4 to help support internal and commercial engine development programs, such as those in Lunar CATALYST. One challenge with spark exciter systems, especially at altitude conditions, is the ignition lead that transmits the high voltage pulse from the exciter to the spark igniter (spark plug). The ignition lead can be prone to corona discharge, reducing the energy delivered by the spark and potentially causing non-ignition events. For the current work, a

  5. Mathematical modeling of the wood ignition process

    NASA Astrophysics Data System (ADS)

    Grishin, A. M.; Yakimov, A. S.

    2013-12-01

    The statements and numerical solution of the problem of igniting the wood wall as a result of the fire seat effect based on the mathematical model of a porous reacting medium are proposed. The original reagent ignition is found to be determined by the processes of drying, pyrolysis (decomposition and synthesis reactions) of dry wood, reaction of the carbon oxide oxidation as well as by the wood thermophysical properties.

  6. 40 CFR 1036.620 - Alternate CO2 standards based on model year 2011 compression-ignition engines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... measured emission rate of the test engine of the applicable baseline 2011 engine family(ies) as described in paragraphs (b) and (c) of this section. Calculate the CO2 emission rate of the baseline test... the transient cycle) is equal to the baseline emission rate multiplied by 0.975. The alternate...

  7. 40 CFR 1036.620 - Alternate CO2 standards based on model year 2011 compression-ignition engines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... measured emission rate of the test engine of the applicable baseline 2011 engine family(ies) as described in paragraphs (b) and (c) of this section. Calculate the CO2 emission rate of the baseline test... the transient cycle) is equal to the baseline emission rate multiplied by 0.975. The alternate...

  8. Utilization of Alcohol Fuel in Spark Ignition and Diesel Engines.

    ERIC Educational Resources Information Center

    Berndt, Don; Stengel, Ron

    These five units comprise a course intended to prepare and train students to conduct alcohol fuel utilization seminars in spark ignition and diesel engines. Introductory materials include objectives and a list of instructor requirements. The first four units cover these topics: ethanol as an alternative fuel (technical and economic advantages,…

  9. 14 CFR 25.1165 - Engine ignition systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... that draw electrical energy from the same source. (c) The design of the engine ignition system must... installed, located, or protected, to minimize the probability of simultaneous failure of two or more wires as a result of mechanical damage, electrical faults, or other cause. (e) No ground wire for any...

  10. 14 CFR 25.1165 - Engine ignition systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... that draw electrical energy from the same source. (c) The design of the engine ignition system must... installed, located, or protected, to minimize the probability of simultaneous failure of two or more wires as a result of mechanical damage, electrical faults, or other cause. (e) No ground wire for any...

  11. Automobile Engine: Basic Ignition Timing. Fordson Bilingual Demonstration Project.

    ERIC Educational Resources Information Center

    Vick, James E.

    These two vocational instructional modules on basic automobile ignition timing and on engine operation, four-stroke cycle, are two of eight such modules designed to assist recently arrived Arab students, limited in English proficiency (LEP), in critical instructional areas in a comprehensive high school. Goal stated for this module is for the…

  12. Utilization of Alcohol Fuel in Spark Ignition and Diesel Engines.

    ERIC Educational Resources Information Center

    Berndt, Don; Stengel, Ron

    These five units comprise a course intended to prepare and train students to conduct alcohol fuel utilization seminars in spark ignition and diesel engines. Introductory materials include objectives and a list of instructor requirements. The first four units cover these topics: ethanol as an alternative fuel (technical and economic advantages,…

  13. High load operation in a homogeneous charge compression ignition engine

    DOEpatents

    Duffy, Kevin P [Metamora, IL; Kieser, Andrew J [Morton, IL; Liechty, Michael P [Chillicothe, IL; Hardy, William L [Peoria, IL; Rodman, Anthony [Chillicothe, IL; Hergart, Carl-Anders [Peoria, IL

    2008-12-23

    A homogeneous charge compression ignition engine is set up by first identifying combinations of compression ratio and exhaust gas percentages for each speed and load across the engines operating range. These identified ratios and exhaust gas percentages can then be converted into geometric compression ratio controller settings and exhaust gas recirculation rate controller settings that are mapped against speed and load, and made available to the electronic

  14. The Quiescent-Chamber Type Compression-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Foster, H H

    1937-01-01

    Report presents the results of performance tests of a single-cylinder 4-stroke-cycle compression-ignition engine having a vertical disk form of combustion chamber without air flow. The number, size, and direction of the orifices of the fuel-injection nozzles used were independently varied. A table and graphs are presented showing the performance of the engine with different nozzles; results of tests at different compression ratios, boost pressures, and coolant temperatures are also included.

  15. Investigations of combustion in ''squish'' chamber spark ignition engines

    SciTech Connect

    James, E.H.

    1984-02-01

    Seemingly inexplicable and intractable observations relating to flame travel time behaviour in 'squish' chambered, spark ignition (S.I.) engines are resolved using a computer model of the combustion process coupled with hot wire anemometry techniques for flow velocity measurements under 'motored' conditions. ''Reverse squish'' is shown to be present during the early part of the expansion stroke and, under certain conditions, this radically reduces combustion intervals in the engine through augmenting the expansion velocity component of flame speed. Mass burning rates are not correspondingly increased however indicating that there is no automatic correlation between flame speeds and turbulence intensities. Computer modelling of the combustion process is shown to provide much more detail than can be obtained from experiments. This technique is used to explain the relative insensitivity of flame travel times part-way across the chamber to compression ratio variation and turbulence level. The pressure dependency of laminar burning velocity as recommended by Mattavi et al is shown to be highly important in this context as also are the increased expansion velocities at the lower compression ratios. A mechanism is suggested whereby overall flame travel times at the end of combustion finally decrease with compression ratio increase to comply with normally observed trends.

  16. LES of an ignition sequence in a gas turbine engine

    SciTech Connect

    Boileau, M.; Staffelbach, G.; Cuenot, B.; Poinsot, T.; Berat, C.

    2008-07-15

    Being able to ignite or reignite a gas turbine engine in a cold and rarefied atmosphere is a critical issue for many manufacturers. From a fundamental point of view, the ignition of the first burner and the flame propagation from one burner to another are phenomena that are usually not studied. The present work is a large eddy simulation (LES) of these phenomena. To simulate a complete ignition sequence in an annular chamber, LES has been applied to the full 360 geometry, including 18 burners. This geometry corresponds to a real gas turbine chamber. Massively parallel computing (700 processors on a Cray XT3 machine) was essential to perform such a large calculation. Results show that liquid fuel injection has a strong influence on the ignition times. Moreover, the rate of flame progress from burner to burner is much higher than the turbulent flame speed due to a major effect of thermal expansion. This flame speed is also strongly modified by the main burner aerodynamics due to the swirled injection. Finally, the variability of the combustor sectors and quadrant ignition times is highlighted. (author)

  17. Simulation of Aldehyde Emissions from an Ethanol Fueled Spark Ignition Engine and Comparison with FTIR Measurements

    NASA Astrophysics Data System (ADS)

    Barros Zaránte, Paola Helena; Sodre, Jose Ricardo

    2016-09-01

    This paper presents a mathematical model that calculates aldehyde emissions in the exhaust of a spark ignition engine fueled with ethanol. The numerical model for aldehyde emissions was developed using FORTRAN software, with the input data obtained from a dedicated engine cycle simulation software, AVL BOOST. The model calculates formaldehyde and acetaldehyde emissions, formed from the partial oxidation of methane, ethane and unburned ethanol. The calculated values were compared with experimental data obtained by Fourier Transform Infrared Spectroscopy (FTIR). The experiments were performed with a mid-size sedan powered by a 1.4-liter spark ignition engine on a chassis dynamometer. In general, the results demonstrate that the concentrations of aldehydes and the source elements increased with engine speed and exhaust gas temperature. A reasonable agreement between simulated and measured values was achieved.

  18. Advanced Technology Spark-Ignition Aircraft Piston Engine Design Study

    NASA Technical Reports Server (NTRS)

    Stuckas, K. J.

    1980-01-01

    The advanced technology, spark ignition, aircraft piston engine design study was conducted to determine the improvements that could be made by taking advantage of technology that could reasonably be expected to be made available for an engine intended for production by January 1, 1990. Two engines were proposed to account for levels of technology considered to be moderate risk and high risk. The moderate risk technology engine is a homogeneous charge engine operating on avgas and offers a 40% improvement in transportation efficiency over present designs. The high risk technology engine, with a stratified charge combustion system using kerosene-based jet fuel, projects a 65% improvement in transportation efficiency. Technology enablement program plans are proposed herein to set a timetable for the successful integration of each item of required advanced technology into the engine design.

  19. The spark-ignition aircraft piston engine of the future

    NASA Technical Reports Server (NTRS)

    Stuckas, K. J.

    1983-01-01

    The advanced technology, spark ignition, aircraft piston engine design study was conducted to determine the improvements that could be made by taking advantage of technology that could reasonably be expected to be made available for an engine intended for production by January 1, 1990. Two engines were proposed to account for levels of technology considered to be moderate risk and high risk. The moderate risk technology engine is a homogeneous charge engine operating on avgas and offers a 40% improvement in transportation efficiency over present designs. The high risk technology engine, with a stratified charge combustion system using kerosene-based jet fuel, projects a 65% improvement in transportation efficiency. Technology enablement program plans are proposed herein to set a timetable for the successful integration of each time of required advanced technology into the engine design.

  20. Precision Engineering within the National Ignition Campaign

    SciTech Connect

    Taylor, J S; Carlisle, K; Klingmann, J L; Geraghty, P; Saito, T T; Montesanti, R C

    2010-02-17

    In this very brief talk, we'll discuss how precision engineering impacts 4 key areas of NIF: (1) Diamond turning of KDP crystals; (2) Mitigation of laser damage on optics; (3) Alignment of lasers, targets, diagnostics; (4) Target fabrication.

  1. A Multicomponent Blend as a Diesel Fuel Surrogate for Compression Ignition Engine Applications

    SciTech Connect

    Pei, Yuanjiang; Mehl, Marco; Liu, Wei; Lu, Tianfeng; Pitz, William J.; Som, Sibendu

    2015-05-12

    A mixture of n-dodecane and m-xylene is investigated as a diesel fuel surrogate for compression ignition engine applications. Compared to neat n-dodecane, this binary mixture is more representative of diesel fuel because it contains an alkyl-benzene which represents an important chemical class present in diesel fuels. A detailed multi-component mechanism for n-dodecane and m-xylene was developed by combining a previously developed n-dodecane mechanism with a recently developed mechanism for xylenes. The xylene mechanism is shown to reproduce experimental ignition data from a rapid compression machine and shock tube, speciation data from the jet stirred reactor and flame speed data. This combined mechanism was validated by comparing predictions from the model with experimental data for ignition in shock tubes and for reactivity in a flow reactor. The combined mechanism, consisting of 2885 species and 11754 reactions, was reduced to a skeletal mechanism consisting 163 species and 887 reactions for 3D diesel engine simulations. The mechanism reduction was performed using directed relation graph (DRG) with expert knowledge (DRG-X) and DRG-aided sensitivity analysis (DRGASA) at a fixed fuel composition of 77% of n-dodecane and 23% m-xylene by volume. The sample space for the reduction covered pressure of 1 – 80 bar, equivalence ratio of 0.5 – 2.0, and initial temperature of 700 – 1600 K for ignition. The skeletal mechanism was compared with the detailed mechanism for ignition and flow reactor predictions. Finally, the skeletal mechanism was validated against a spray flame dataset under diesel engine conditions documented on the Engine Combustion Network (ECN) website. These multi-dimensional simulations were performed using a Representative Interactive Flame (RIF) turbulent combustion model. Encouraging results were obtained compared to the experiments with regards to the predictions of ignition delay and lift-off length at different ambient temperatures.

  2. The spark-ignition aircraft piston engine of the future

    NASA Technical Reports Server (NTRS)

    Stuckas, K. J.

    1980-01-01

    Areas of advanced technology appropriate to the design of a spark-ignition aircraft piston engine for the late 1980 time period were investigated and defined. Results of the study show that significant improvements in fuel economy, weight and size, safety, reliability, durability and performance may be achieved with a high degree of success, predicated on the continued development of advances in combustion systems, electronics, materials and control systems.

  3. Chemical Kinetic Models for Advanced Engine Combustion

    SciTech Connect

    Pitz, William J.; Mehl, Marco; Westbrook, Charles K.

    2014-10-22

    The objectives for this project are as follows: Develop detailed chemical kinetic models for fuel components used in surrogate fuels for compression ignition (CI), homogeneous charge compression ignition (HCCI) and reactivity-controlled compression-ignition (RCCI) engines; and Combine component models into surrogate fuel models to represent real transportation fuels. Use them to model low-temperature combustion strategies in HCCI, RCCI, and CI engines that lead to low emissions and high efficiency.

  4. Ignition distributor for internal combustion engines

    SciTech Connect

    Nakamura, N.; Yagi, K.; Yamaguchi, S.; Yoshida, I.; Atsumi, S.

    1987-07-21

    A distributor is described comprising: fixed electrodes adapted to be electrically connected to sparking plugs of an internal combustion engine, and a rotating electrode adapted to be rotatable in synchronism with a crank of the internal combustion engine and forming a narrow gap sequentially with each of the fixed electrodes. It is featured that at least one of the electrodes and the rotating electrode is made of a ceramic that has the function of a varistor and has as a main material at least one of zinc oxide (ZnO) and nickel oxide (NiO) and as an additive at least one of bismuth oxide (Bi/sub 2/O/sub 3/), manganese dioxide (MnO/sub 2/) and cobalt oxide (CoO), which are sintered together.

  5. A comparison between direct spark ignition and prechamber ignition in an internal combustion engine

    NASA Astrophysics Data System (ADS)

    Cloutman, L. D.

    1993-12-01

    We simulated the flow field and flame propagation near top dead center in a generic large-bore internal combustion engine using the COYOTE computer program, which is based on the full Navier-Stokes equations for a fluid mixture. The combustion chamber is a right circular cylinder, and the main charge is uniformly premixed. The calculations are axisymmetric. The results illustrate the differences in flow patterns, flame propagation, and thermal NO production between ignition with a spark plug and with a small prechamber. In the spark-ignited case, the flame propagates away from the spark plug approximately as a segment of a spherical surface, just as expected. With the prechamber, a high speed jet of hot combustion products shoots into the main chamber, quickly producing a large flame sheet that spreads along the piston face. The prechamber run consumes all of the fuel in half the time required by the spark-ignited case. The two cases produce comparable amounts of thermal NO at the end of fuel combustion.

  6. A comparison between direct spark ignition and prechamber ignition in an internal combustion engine

    SciTech Connect

    Cloutman, L.D.

    1993-12-03

    We simulated the flow field and flame propagation near top dead center in a generic large-bore internal combustion engine using the COYOTE computer program, which is based on the full Navier-Stokes equations for a fluid mixture. The combustion chamber is a right circular cylinder, and the main charge is uniformly premixed. The calculations are axisymmetric. The results illustrate the differences in flow patterns, flame propagation, and thermal NO production between ignition with a spark plug and with a small prechamber. In the spark-ignited case, the flame propagates away from the spark plug approximately as a segment of a spherical surface, just as expected. With the prechamber, a high speed jet of hot combustion products shoots into the main chamber, quickly producing a large flame sheet that spreads along the piston face. The prechamber run consumes all of the fuel in half the time required by the spark-ignited case. The two cases produce comparable amounts of thermal NO at the end of fuel combustion.

  7. Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions

    DOE PAGES

    Pei, Yuanjiang; Som, Sibendu; Pomraning, Eric; ...

    2015-10-14

    An n-dodecane spray flame (Spray A from Engine Combustion Network) was simulated using a δ function combustion model along with a dynamic structure large eddy simulation (LES) model to evaluate its performance at engine-relevant conditions and to understand the transient behavior of this turbulent flame. The liquid spray was treated with a traditional Lagrangian method and the gas-phase reaction was modeled using a δ function combustion model. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. Significantly different flame structures and ignition processes are observed for the LES compared to those of Reynolds-averaged Navier—Stokes (RANS) predictions. Themore » LES data suggests that the first ignition initiates in a lean mixture and propagates to a rich mixture, and the main ignition happens in the rich mixture, preferably less than 0.14 in mixture fraction space. LES was observed to have multiple ignition spots in the mixing layer simultaneously while the main ignition initiates in a clearly asymmetric fashion. The temporal flame development also indicates the flame stabilization mechanism is auto-ignition controlled. Soot predictions by LES present much better agreement with experiments compared to RANS, both qualitatively and quantitatively. Multiple realizations for LES were performed to understand the realization to realization variation and to establish best practices for ensemble-averaging diesel spray flames. The relevance index analysis suggests that an average of 5 and 6 realizations can reach 99% of similarity to the target average of 16 realizations on the mixture fraction and temperature fields, respectively. In conclusion, more realizations are necessary for the hydroxide (OH) and soot mass fractions due to their high fluctuations.« less

  8. Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions

    SciTech Connect

    Pei, Yuanjiang; Som, Sibendu; Pomraning, Eric; Senecal, Peter K.; Skeen, Scott A.; Manin, Julien; Pickett, Lyle M.

    2015-10-14

    An n-dodecane spray flame (Spray A from Engine Combustion Network) was simulated using a δ function combustion model along with a dynamic structure large eddy simulation (LES) model to evaluate its performance at engine-relevant conditions and to understand the transient behavior of this turbulent flame. The liquid spray was treated with a traditional Lagrangian method and the gas-phase reaction was modeled using a δ function combustion model. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. Significantly different flame structures and ignition processes are observed for the LES compared to those of Reynolds-averaged Navier—Stokes (RANS) predictions. The LES data suggests that the first ignition initiates in a lean mixture and propagates to a rich mixture, and the main ignition happens in the rich mixture, preferably less than 0.14 in mixture fraction space. LES was observed to have multiple ignition spots in the mixing layer simultaneously while the main ignition initiates in a clearly asymmetric fashion. The temporal flame development also indicates the flame stabilization mechanism is auto-ignition controlled. Soot predictions by LES present much better agreement with experiments compared to RANS, both qualitatively and quantitatively. Multiple realizations for LES were performed to understand the realization to realization variation and to establish best practices for ensemble-averaging diesel spray flames. The relevance index analysis suggests that an average of 5 and 6 realizations can reach 99% of similarity to the target average of 16 realizations on the mixture fraction and temperature fields, respectively. In conclusion, more realizations are necessary for the hydroxide (OH) and soot mass fractions due to their high fluctuations.

  9. Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions

    SciTech Connect

    Pei, Yuanjiang; Som, Sibendu; Pomraning, Eric; Senecal, Peter Kelly; Skeen, S; Manin, J; Pickett, Lyle

    2015-12-01

    An n-dodecane spray flame (Spray A from Engine Combustion Network) was simulated using a detailed combustion model along with a dynamic structure LES model to evaluate its performance at engine-relevant conditions and understand the transient behavior of this turbulent flame. The liquid spray was treated with a traditional Lagrangian method and the gas-phase reaction was modeled using a detailed combustion model. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. Significantly different flame structures and ignition processes are observed for the LES compared to those of RANS predictions. The LES data suggests that the first ignition initiates in lean mixture and propagates to rich mixture, and the main ignition happens in rich mixture, preferable less than 0.14 in mixture fraction space. LES was observed to have multiple ignition spots in the mixing layer simultaneously while the main ignition initiates in a clearly asymmetric fashion. The temporal flame development also indicates the flame stabilization mechanism is auto-ignition controlled and modulated by flame propagation. Soot predictions by LES present much better agreement with experiments compared to RANS both qualitatively and quantitatively. Multiple realizations for LES were performed to understand the realization to realization variation and to establish best practices for ensemble-averaging diesel spray flames. The relevance index analysis suggests that an average of 2 and 5 realizations can reach 99\\% of similarity to the target average of 16 realizations on the temperature and mixture fraction fields, respectively. However, more realizations are necessary for OH and soot mass fraction due to their high fluctuations.

  10. Spray ignition measurements in a constant volume combustion vessel under engine-relevant conditions

    NASA Astrophysics Data System (ADS)

    Ramesh, Varun

    Pressure-based and optical diagnostics for ignition delay (ID) measurement of a diesel spray from a multi-hole nozzle were investigated in a constant volume combustion vessel (CVCV) at conditions similar to those in a conventional diesel engine at the start of injection (SOI). It was first hypothesized that compared to an engine, the shorter ID in a CVCV was caused by NO, a byproduct of premixed combustion. The presence of a significant concentration of NO+NO2 was confirmed experimentally and by using a multi-zone model of premixed combustion. Experiments measuring the effect of NO on ID were performed at conditions relevant to a conventional diesel engine. Depending on the temperature regime and the nature of the fuel, NO addition was found to advance or retard ignition. Constant volume ignition simulations were capable of describing the observed trends; the magnitudes were different due to the physical processes involved in spray ignition, not modeled in the current study. The results of the study showed that ID is sensitive to low NO concentrations (<100 PPM) in the low-temperature regime. A second source of uncertainty in pressure-based ID measurement is the systematic error associated with the correction used to account for the speed of sound. Simultaneous measurements of volumetric OH chemiluminescence (OHC) and pressure during spray ignition found the OHC to closely resemble the pressure-based heat release rate for the full combustion duration. The start of OHC was always found to be shorter than the pressure-based ID for all fuels and conditions tested by 100 ms. Experiments were also conducted measuring the location and timing of high-temperature ignition and the steady-state lift-off length by high-speed imaging of OHC during spray ignition. The delay period calculated using the measured ignition location and the bulk average speed of sound was in agreement with the delay between OHC and the pressure-based ID. Results of the study show that start of OHC

  11. Combustion in a High-Speed Compression-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Rothrock, A M

    1933-01-01

    An investigation conducted to determine the factors which control the combustion in a high-speed compression-ignition engine is presented. Indicator cards were taken with the Farnboro indicator and analyzed according to the tangent method devised by Schweitzer. The analysis show that in a quiescent combustion chamber increasing the time lag of auto-ignition increases the maximum rate of combustion. Increasing the maximum rate of combustion increases the tendency for detonation to occur. The results show that by increasing the air temperature during injection the start of combustion can be forced to take place during injection and so prevent detonation from occurring. It is shown that the rate of fuel injection does not in itself control the rate of combustion.

  12. Ignition angle advancer for internal combustion engine

    SciTech Connect

    Yamazaki, T.

    1986-08-19

    This patent describes a throttle and spark advance control system for an internal combustion engine having a spark advance mechanism and a throttle valve comprising an operator controlled element, a throttle control lever supported for pivotal movement about an axis and directly connected to the operator controlled element for rotation under operator control. It also includes means for positively connecting the throttle control lever to the throttle valve for positioning the throttle valve in response to movement of the throttle control lever. A spark advance control lever supported for pivotal movement about an axis is included as well as motion transmitting means for operatively connecting the spark advance control lever to the throttle control lever for pivotal movement of the spark advance control lever about its axis in response to pivotal movement of the throttle control lever about its axis and the spark control lever to the spark advance mechanism for controlling the position of the spark advance mechanism in response to the position of the throttle control lever.

  13. Reactivity Controlled Compression Ignition (RCCI) Combustion on a Multi-Cylinder Light-Duty Diesel Engine

    SciTech Connect

    Curran, Scott; Hanson, Reed M; Wagner, Robert M

    2012-01-01

    Reactivity controlled compression ignition is a low-temperature combustion technique that has been shown, both in computational fluid dynamics modeling and single-cylinder experiments, to obtain diesel-like efficiency or better with ultra-low nitrogen oxide and soot emissions, while operating primarily on gasoline-like fuels. This paper investigates reactivity controlled compression ignition operation on a four-cylinder light-duty diesel engine with production-viable hardware using conventional gasoline and diesel fuel. Experimental results are presented over a wide speed and load range using a systematic approach for achieving successful steady-state reactivity controlled compression ignition combustion. The results demonstrated diesel-like efficiency or better over the operating range explored with low engine-out nitrogen oxide and soot emissions. A peak brake thermal efficiency of 39.0% was demonstrated for 2600 r/min and 6.9 bar brake mean effective pressure with nitrogen oxide emissions reduced by an order of magnitude compared to conventional diesel combustion operation. Reactivity controlled compression ignition emissions and efficiency results are compared to conventional diesel combustion operation on the same engine.

  14. RAILPLUG IGNITION SYSTEM FOR ENHANCED ENGINE PERFORMANCE AND REDUCED MAINTENANCE

    SciTech Connect

    Ron Matthews

    2003-08-20

    During the first year of this project, three experimental subtasks and four modeling subtasks were scheduled to begin. Five of these 7 subtasks were scheduled for completion by the end of the first year. Both experimental tasks were completed on schedule. No experimental data were scheduled for the first year. The four modeling tasks are progressing well. However, two of the numerical tasks have been delayed somewhat. A simplified plasma kinetics mechanism was developed and tested against a detailed model. The agreement was quite good. A simplified kinetics mechanism for flame propagation was also developed and validated via comparisons against an elementary kinetics mechanism. Again, the agreement was quite good. The 2D spark ignition process model was exercised to ensure stability but the 3D version was not completed. Excellent progress was made on the ignition circuit model, but it is not yet finished. The delays in these two subtasks are not expected to impact the schedule for the overall project.

  15. Utilization of waste glycerin to fuelling of spark ignition engines

    NASA Astrophysics Data System (ADS)

    Stelmasiak, Z.; Pietras, D.

    2016-09-01

    The paper discusses a possibilities of usage a simple alcohols to fuelling of spark ignition engines. Methanol and blends of methanol with glycerin, being a waste product from production of bio-components to fuels based on rapeseed oil, have been used in course of the investigations. The main objective of the research was to determine possibilities of utilization of glycerin to blending of engine fuels. The investigations have been performed using the Fiat 1100 MPI engine. Parameters obtained with the engine powered by pure methanol and by methanol- glycerin mixtures with 10÷30%vol content of glycerin were compared to parameters of the engine fuelled conventionally with the E95 gasoline. The investigations have shown increase of overall efficiency of the engine run on pure methanol with 2.5÷5.0%, and run on the mixture having 10% addition of glycerin with 2.0÷7.8%. Simultaneously, fuelling of the engine with the investigated alcohols results in reduced concentration of toxic components in exhaust gases like: CO, THC and NOx, as well as the greenhouse gas CO2.

  16. Perspective of laser-induced plasma ignition of hydrocarbon fuel in Scramjet engine

    NASA Astrophysics Data System (ADS)

    Yang, Leichao; Li, Xiaohui; Liang, Jianhan; Yu, Xin; Li, Xipeng

    2016-01-01

    Laser-induced plasma ignition of an ethylene fuelled cavity was successfully conducted in a model scramjet engine combustor. The ethylene was injected 10mm upstream of cavity flameholder from 3 orifices 60 degree inclined relative to freestream direction. The 1064nm laser beam, from a Q-switched Nd:YAG laser source running at 3Hz and 200mJ per pulse, was focused into cavity for ignition. High speed photography was used to capture the transient ignition process. The laser-induced gas breakdown, flame kernel generation and propagation were all recorded and ensuing stable supersonic combustion was established in cavity. The flame kernel is found rotating anti-clockwise and gradually moves upwards as the entrainment of circulation flow in cavity. The flame is then stretched from leading edge to trailing edge to fully fill the entire cavity. Eventually, a stable combustion is achieved roughly 900μs after the laser pulse. The results show promising potentials for practical application. The perspective of laser-induced plasma ignition of hydrocarbon fuel in scramjet engine is outlined.

  17. Conversion of a diesel engine to a spark ignition natural gas engine

    SciTech Connect

    1996-09-01

    Requirements for alternatives to diesel-fueled vehicles are developing, particularly in urban centers not in compliance with mandated air quality standards. An operator of fleets of diesel- powered vehicles may be forced to either purchase new vehicles or equip some of the existing fleets with engines designed or modified to run on alternative fuels. In converting existing vehicles, the operator can either replace the existing engine or modify it to burn an alternative fuel. Work described in this report addresses the problem of modifying an existing diesel engine to operate on natural gas. Tecogen has developed a technique for converting turbocharged automotive diesel engines to operate as dedicated spark-ignition engines with natural gas fuel. The engine cycle is converted to a more-complete-expansion cycle in which the expansion ratio of the original engine is unchanged while the effective compression ratio is lowered, so that engine detonation is avoided. The converted natural gas engine, with an expansion ratio higher than in conventional spark- ignition natural gas engines, offers thermal efficiency at wide-open- throttle conditions comparable to its diesel counterpart. This allows field conversion of existing engines. Low exhaust emissions can be achieved when the engine is operated with precise control of the fuel air mixture at stoichiometry with a 3-way catalyst. A Navistar DTA- 466 diesel engine with an expansion ratio of 16.5 to 1 was converted in this way, modifying the cam profiles, increasing the turbocharger boost pressure, incorporating an aftercooler if not already present, and adding a spark-ignition system, natural gas fuel management system, throttle body for load control, and an electronic engine control system. The proof-of-concept engine achieved a power level comparable to that of the diesel engine without detonation. A conversion system was developed for the Navistar DT 466 engine. NOx emissions of 1.5 g/bhp-h have been obtained.

  18. Dynamic control of a homogeneous charge compression ignition engine

    DOEpatents

    Duffy, Kevin P [Metamora, IL; Mehresh, Parag [Peoria, IL; Schuh, David [Peoria, IL; Kieser, Andrew J [Morton, IL; Hergart, Carl-Anders [Peoria, IL; Hardy, William L [Peoria, IL; Rodman, Anthony [Chillicothe, IL; Liechty, Michael P [Chillicothe, IL

    2008-06-03

    A homogenous charge compression ignition engine is operated by compressing a charge mixture of air, exhaust and fuel in a combustion chamber to an autoignition condition of the fuel. The engine may facilitate a transition from a first combination of speed and load to a second combination of speed and load by changing the charge mixture and compression ratio. This may be accomplished in a consecutive engine cycle by adjusting both a fuel injector control signal and a variable valve control signal away from a nominal variable valve control signal. Thereafter in one or more subsequent engine cycles, more sluggish adjustments are made to at least one of a geometric compression ratio control signal and an exhaust gas recirculation control signal to allow the variable valve control signal to be readjusted back toward its nominal variable valve control signal setting. By readjusting the variable valve control signal back toward its nominal setting, the engine will be ready for another transition to a new combination of engine speed and load.

  19. Development of High Efficiency Clean Combustion Engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines

    SciTech Connect

    Marriott, Craig; Gonzalez, Manual; Russell, Durrett

    2011-06-30

    This report summarizes activities related to the revised STATEMENT OF PROJECT OBJECTIVES (SOPO) dated June 2010 for the Development of High-Efficiency Clean Combustion engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines (COOPERATIVE AGREEMENT NUMBER DE-FC26-05NT42415) project. In both the spark- (SI) and compression-ignition (CI) development activities covered in this program, the goal was to develop potential production-viable internal combustion engine system technologies that both reduce fuel consumption and simultaneously met exhaust emission targets. To be production-viable, engine technologies were also evaluated to determine if they would meet customer expectations of refinement in terms of noise, vibration, performance, driveability, etc. in addition to having an attractive business case and value. Prior to this activity, only proprietary theoretical / laboratory knowledge existed on the combustion technologies explored The research reported here expands and develops this knowledge to determine series-production viability. Significant SI and CI engine development occurred during this program within General Motors, LLC over more than five years. In the SI program, several engines were designed and developed that used both a relatively simple multi-lift valve train system and a Fully Flexible Valve Actuation (FFVA) system to enable a Homogeneous Charge Compression Ignition (HCCI) combustion process. Many technical challenges, which were unknown at the start of this program, were identified and systematically resolved through analysis, test and development. This report documents the challenges and solutions for each SOPO deliverable. As a result of the project activities, the production viability of the developed clean combustion technologies has been determined. At this time, HCCI combustion for SI engines is not considered production-viable for several reasons. HCCI combustion is excessively sensitive to control variables

  20. Auto-ignition of hydrazine by engineering materials

    NASA Technical Reports Server (NTRS)

    Perkins, J. H.; Riehl, W. A.

    1978-01-01

    Hydrazine, being a monopropellant, can explode and/or detonate in contact with some materials. This has been generally recognized and minimized by testing the compatibility of engineering materials with hydrazine at ambient temperature. Very limited tests have been done at elevated temperatures. To assess the potential hazard of hydrazine leakage into a propulsion compartment (boattail), autoignition characteristics of hydrazine were tested on 18 engineering materials and coatings at temperatures of 120 C to over 330 C. Furthermore, since hydrazine can decompose violently in nitrogen or helium, common purging cannot assure safety. Therefore tests were also made in nitrogen. Detonations occurred on contact with five materials in air. Similar tests in nitrogen did not lead to ignition.

  1. Flatness-based nonlinear embedded control and filtering for spark-ignited engines

    NASA Astrophysics Data System (ADS)

    Rigatos, Gerasimos; Siano, Pierluigi; Arsie, Ivan

    2014-10-01

    Highly efficient embedded control units for transportation means make use of advanced nonlinear control and estimation methods. In this research article a new nonlinear filtering and control method is applied to spark ignited (SI) engines. The proposed SI engine's control scheme requires the implementation of differential flatness theory together with a new nonlinear filtering approach (known as Derivative-free nonlinear Kalman Filtering). The considered method succeeds the efficient control of the SI engine parameters such as intake pressure and turn speed. To bring the control loop at a working stage additional problems have to be solved. These are for instance that (i) certain variables of the engine's state vector cannot be measured directly (e.g. the ones associated with input pressure), (ii) there are inaccuracies in the dynamic model of the SI engine while external perturbations and disturbances (such as friction torques) are exerted to the engine. The performance of the proposed control scheme is tested through simulation experiments.

  2. Lightweight, low compression aircraft diesel engine. [converting a spark ignition engine to the diesel cycle

    NASA Technical Reports Server (NTRS)

    Gaynor, T. L.; Bottrell, M. S.; Eagle, C. D.; Bachle, C. F.

    1977-01-01

    The feasibility of converting a spark ignition aircraft engine to the diesel cycle was investigated. Procedures necessary for converting a single cylinder GTS10-520 are described as well as a single cylinder diesel engine test program. The modification of the engine for the hot port cooling concept is discussed. A digital computer graphics simulation of a twin engine aircraft incorporating the diesel engine and Hot Fort concept is presented showing some potential gains in aircraft performance. Sample results of the computer program used in the simulation are included.

  3. Structure ignition assessment model (SIAM)\\t

    Treesearch

    Jack D. Cohen

    1995-01-01

    Major wildland/urban interface fire losses, principally residences, continue to occur. Although the problem is not new, the specific mechanisms are not well known on how structures ignite in association with wildland fires. In response to the need for a better understanding of wildland/urban interface ignition mechanisms and a method of assessing the ignition risk,...

  4. 76 FR 67184 - California State Nonroad Engine Pollution Control Standards; Large Spark-Ignition (LSI) Engines...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-31

    ... Air Resources Board (CARB) has notified EPA that it has amended its emission standards and certification and test procedures for large spark-ignition nonroad engines (``LSI Emission Standards''). CARB... tractors, sweepers/scrubbers, and airport ] ground support equipment. CARB requests that EPA find the...

  5. Lean-burn hydrogen spark-ignited engines: the mechanical equivalent to the fuel cell

    SciTech Connect

    Aceves, S.M.; Smith, J.R.

    1996-10-01

    Fuel cells are considered as the ideal power source for future vehicles, due to their high efficiency and low emissions. However, extensive use of fuel cells in light-duty vehicles is likely to be years away, due to their high manufacturing cost. Hydrogen-fueled, spark-ignited, homogeneous-charge engines offer a near-term alternative to fuel cells. Hydrogen in a spark-ignited engine can be burned at very low equivalence ratios, so that NO[sub x] emissions can be reduced to less than 10 ppm without catalyst. HC and CO emissions may result from oxidation of engine oil, but by proper design are negligible (a few ppm). Lean operation also results in increased indicated efficiency due to the thermodynamic properties of the gaseous mixture contained in the cylinder. The high effective octane number of hydrogen allows the use of a high compression ratio, further increasing engine efficiency. In this paper, a simplified engine model is used for predicting hydrogen engine efficiency and emissions. The model uses basic thermodynamic equations for the compression and expansion processes, along with an empirical correlation for heat transfer, to predict engine indicated efficiency. A friction correlation and a supercharger/turbocharger model are then used to calculate brake thermal efficiency. The model is validated with many 1345 experimental points obtained in a recent evaluation of a hydrogen research engine. The experimental data are used to adjust the empirical constants in the heat release rate and heat transfer correlation. The adjusted engine model predicts pressure traces, indicated efficiency and NO,, emissions with good accuracy over the range of speed, equivalence ratio and manifold pressure experimentally covered.

  6. Spark Ignition Characteristics of a LO2/LCH4 Engine at Altitude Conditions

    NASA Technical Reports Server (NTRS)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine's augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter.s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  7. Spark Ignition Characteristics of a L02/LCH4 Engine at Altitude Conditions

    NASA Technical Reports Server (NTRS)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine s augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  8. Potential of spark ignition engine, 1979 summary source document. Final report

    SciTech Connect

    Trella, T.; Zub, R.; Colello, R.

    1980-03-01

    This report provides an assessment of the potential for spark ignition engines passenger cars and light trucks. The assessment includes: tradeoffs between fuel economy and emissions; improvements in spark ignition engine efficiency; improvements in engine parasitics; improvements due to transmissions; effect of aerodynamic drag and tire rolling resistance on fuel economy; effect on performance and fuel economy of weight and axle ratio; lubricant improvements; impact of fuels; and noise considerations.

  9. Calculations of the Performance of a Compression-Ignition Engine-Compressor Turbine Combination I : Performance of a Highly Supercharged Compression-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Sanders, J. C.; Mendelson, Alexander

    1945-01-01

    Small high-speed single-cylinder compression-ignition engines were tested to determine their performance characteristics under high supercharging. Calculations were made on the energy available in the exhaust gas of the compression-ignition engines. The maximum power at any given maximum cylinder pressure was obtained when the compression pressure was equal to the maximum cylinder pressure. Constant-pressure combustion was found possible at an engine speed of 2200 rpm. Exhaust pressures and temperatures were determined from an analysis of indicator cards. The analysis showed that, at rich mixtures with the exhaust back pressure equal to the inlet-air pressure, there is excess energy available for driving a turbine over that required for supercharging. The presence of this excess energy indicates that a highly supercharged compression-ignition engine might be desirable as a compressor and combustion chamber for a turbine.

  10. Spark-ignition, air-compressing, internal combustion engine

    SciTech Connect

    Chmela, F.; Herzog, W.; Meier, R.

    1988-09-20

    This patent describes a spark-ignition, air-compressing, internal combustion engine that has direct ignition of a major portion of the fuel by means of a jet onto the wall of the combustion chamber that is provided, in the shape of a body of revolution, in the piston, whereby rotary motion is imparted by means known per se to the inflowing air in the direction of the injected fuel jet so as to cause the fuel to be removed gradually in the vapor state from the wall of the combustion chamber and to be mixed with the air, the injection nozzle being located in the cylinder head near the combustion chamber rim, with the spark plug, which is disposed opposite the injection nozzle, extending into the combustion chamber in the top dead center position of the piston, with the side wall of the combustion chamber, when viewed in cross section, being formed by two arcs that blend into each other and have respective radii of curvature R/sub 1/, R/sub 2/, the first arc having a radius R/sub 1/ that extends from a restricted combustion chamber opening down to the maximum combustion chamber diameter D/sub B/, and the second arc having a radius R/sub 2/ that extends down to the bottom of the combustion chamber and blends into the latter. The maximum combustion chamber diameter D/sub B/ being 0.5 to 0.7 times the diameter D/sub K/ of the piston and being at a defined depth t/sub D/ from the piston crown relative to the depth T/sub B/ of the combustion chamber, the ratio of the diameter d/sub H/ of the combustion chamber opening to the maximum combustion chamber diameter D/sub B/.

  11. Chemical kinetics of octane sensitivity in a spark-ignition engine (Chemical Kinetics of Octane Sensitivity in a Spark Ignition Engine)

    DOE PAGES

    Westbrook, Charles K.; Mehl, Marco; Pitz, William J.; ...

    2016-07-11

    This article uses a chemical kinetic modeling approach to study the influences of fuel molecular structure on Octane Sensitivity (OS) in Spark Ignition (SI) engines. Octane Sensitivity has the potential to identify fuels that can be used in next-generation high compression, turbocharged SI engines to avoid unwanted knocking conditions and extend the range of operating conditions that can be used in such engines. While the concept of octane numbers of different fuels has been familiar for many years, the variations of their values and their role in determining Octane Sensitivity have not been addressed previously in terms of the basicmore » structures of the fuel molecules. In particular, the importance of electron delocalization on low temperature hydrocarbon reactivity and its role in determining OS in engine fuel is described here for the first time. Finally, the role of electron delocalization on fuel reactivity and Octane Sensitivity is illustrated for a very wide range of engine fuel types, including n-alkane, 1-olefin, n-alcohol, and n-alkyl benzenes, and the unifying features of these fuels and their common trends, using existing detailed chemical kinetic reaction mechanisms that have been collected and unified to produce an overall model with unprecedented capabilities.« less

  12. Chemical kinetics of octane sensitivity in a spark-ignition engine (Chemical Kinetics of Octane Sensitivity in a Spark Ignition Engine)

    SciTech Connect

    Westbrook, Charles K.; Mehl, Marco; Pitz, William J.; Sjöberg, Magnus

    2016-07-11

    This article uses a chemical kinetic modeling approach to study the influences of fuel molecular structure on Octane Sensitivity (OS) in Spark Ignition (SI) engines. Octane Sensitivity has the potential to identify fuels that can be used in next-generation high compression, turbocharged SI engines to avoid unwanted knocking conditions and extend the range of operating conditions that can be used in such engines. While the concept of octane numbers of different fuels has been familiar for many years, the variations of their values and their role in determining Octane Sensitivity have not been addressed previously in terms of the basic structures of the fuel molecules. In particular, the importance of electron delocalization on low temperature hydrocarbon reactivity and its role in determining OS in engine fuel is described here for the first time. Finally, the role of electron delocalization on fuel reactivity and Octane Sensitivity is illustrated for a very wide range of engine fuel types, including n-alkane, 1-olefin, n-alcohol, and n-alkyl benzenes, and the unifying features of these fuels and their common trends, using existing detailed chemical kinetic reaction mechanisms that have been collected and unified to produce an overall model with unprecedented capabilities.

  13. Chemical kinetics of octane sensitivity in a spark-ignition engine (Chemical Kinetics of Octane Sensitivity in a Spark Ignition Engine)

    SciTech Connect

    Westbrook, Charles K.; Mehl, Marco; Pitz, William J.; Sjöberg, Magnus

    2016-07-11

    This article uses a chemical kinetic modeling approach to study the influences of fuel molecular structure on Octane Sensitivity (OS) in Spark Ignition (SI) engines. Octane Sensitivity has the potential to identify fuels that can be used in next-generation high compression, turbocharged SI engines to avoid unwanted knocking conditions and extend the range of operating conditions that can be used in such engines. While the concept of octane numbers of different fuels has been familiar for many years, the variations of their values and their role in determining Octane Sensitivity have not been addressed previously in terms of the basic structures of the fuel molecules. In particular, the importance of electron delocalization on low temperature hydrocarbon reactivity and its role in determining OS in engine fuel is described here for the first time. Finally, the role of electron delocalization on fuel reactivity and Octane Sensitivity is illustrated for a very wide range of engine fuel types, including n-alkane, 1-olefin, n-alcohol, and n-alkyl benzenes, and the unifying features of these fuels and their common trends, using existing detailed chemical kinetic reaction mechanisms that have been collected and unified to produce an overall model with unprecedented capabilities.

  14. Fuel Effects on Ignition and Their Impact on Advanced Combustion Engines (Poster)

    SciTech Connect

    Taylor, J.; Li, H.; Neill, S.

    2006-08-01

    The objective of this report is to develop a pathway to use easily measured ignition properties as metrics for characterizing fuels in advanced combustion engine research--correlate IQT{trademark} measured parameters with engine data. In HCCL engines, ignition timing depends on the reaction rates throughout compression stroke: need to understand sensitivity to T, P, and [O{sub 2}]; need to rank fuels based on more than one set of conditions; and need to understand how fuel composition (molecular species) affect ignition properties.

  15. Modeling the Auto-Ignition of Biodiesel Blends with a Multi-Step Model

    SciTech Connect

    Toulson, Dr. Elisa; Allen, Casey M; Miller, Dennis J; McFarlane, Joanna; Schock, Harold; Lee, Tonghun

    2011-01-01

    There is growing interest in using biodiesel in place of or in blends with petrodiesel in diesel engines; however, biodiesel oxidation chemistry is complicated to directly model and existing surrogate kinetic models are very large, making them computationally expensive. The present study describes a method for predicting the ignition behavior of blends of n-heptane and methyl butanoate, fuels whose blends have been used in the past as a surrogate for biodiesel. The autoignition is predicted using a multistep (8-step) model in order to reduce computational time and make this a viable tool for implementation into engine simulation codes. A detailed reaction mechanism for n-heptane-methyl butanoate blends was used as a basis for validating the multistep model results. The ignition delay trends predicted by the multistep model for the n-heptane-methyl butanoate blends matched well with that of the detailed CHEMKIN model for the majority of conditions tested.

  16. Sunflower oil as a fuel for compression ignition engines

    SciTech Connect

    Tahir, A.R.; Lapp, H.M.; Buchanan, L.C.

    1982-01-01

    Sunflower oil has emerged among the vegetable oils as potential fuel alternatives. The Province of Manitoba is the major producer of sunflower oil in Canada. This study was initiated to investigate the fuel-related physical properties and performance characteristics in compression ignition engines. The results for sunflower oil were summarized and compared with No. 2 diesel fuel. The most detrimental parameter in the use of sunflower oil is its higher viscosity which is about 14 times higher than diesel fuel at 37.78/sup 0/C. The problem of higher viscosity can be solved by transesterification of sunflower oil to its methyl ester. The cetane number of sunflower oil is a little less than the minimum value of 40 for No. 2 diesel fuel. Specific fuel consumption was higher due to its lower energy value whereas thermal efficiency was satisfactory when compared with No. 2 diesel fuel. Oxidation of sunflower oil left heavy gum and wax deposits on the stationary engine parts and the test bench equipment. Lower levels of corrosion can be expected on metal parts due to the lower sulfur content in the sunflower oil. Fire hazards associated with fuel handling will be reduced because of the higher flash point of sunflower oil. 5 figures, 4 tables. (DP)

  17. Interpreting Shock Tube Ignition Data

    DTIC Science & Technology

    2003-10-01

    times only for high concentrations (of order 1% fuel or greater). The requirements of engine (IC, HCCI , CI and SI) modelers also present a different...Paper 03F-61 Interpreting Shock Tube Ignition Data D. F. Davidson and R. K. Hanson Mechanical Engineering ... Engineering Department Stanford University, Stanford CA 94305 Abstract Chemical kinetic modelers make extensive use of shock tube ignition data

  18. Modelling turbulent flame ignition and blowout

    NASA Technical Reports Server (NTRS)

    Radhakrishnan, K.; Heywood, J. B.

    1979-01-01

    A statistical mixing model incorporating an overall rate equation to describe the fuel oxidation process was developed for studies of ignition and blowout in a combustor primary zone. This zone is treated as a partially stirred reactor whose composition is described by a statistical ensemble of equal mass fluid elements. This ensemble experiences mixing interactions, which represent the turbulent mixing process, at time intervals governed by an empirically determined mixing frequency. Each mixing interaction is computed by ramdomly selecting two different elements which are then allowed to mix completely so that they reach a mean composition depending on their thermodynamic states prior to mixing. The two elements then separate, and the chemical kinetics proceed depending on their new composition and temperature.

  19. RAILPLUG IGNITION SYSTEM FOR ENHANCED ENGINE PERFORMANCE AND REDUCED MAINTENANCE

    SciTech Connect

    Ron Matthews

    2003-05-29

    During the first 6 months of this project, four subtasks were scheduled. Two of these commenced earlier than originally proposed. The experimental task, development of new railplug designs, was completed on schedule. The three numerical subtasks were not completed on schedule. However, this is not expected to affect the capability to complete the overall project on schedule. Because we are early in the project, no results or conclusions were generated. Our progress included development of new railplug geometries, to be tested during the second 6 months of the project, and development of an initial 3D model. Progress was also made in development of the appropriate chemical kinetics and generation of a model for the ignition circuit.

  20. Flatness-based embedded control in successive loops for spark-ignited engines

    NASA Astrophysics Data System (ADS)

    Rigatos, Gerasimos

    2015-11-01

    Embedded control units for transportation systems make use of advanced nonlinear control methods. In this research article a new nonlinear control method is applied to spark ignited (SI) engines. The proposed SI engine's control scheme is based on differential flatness theory The considered method succeeds the efficient control of the SI engine parameters such as intake pressure and turn speed. The method makes use of a state-space model of the SI-engine in the so-called triangular form. The controller design proceeds by showing that each row of the state-space model of the SI engine stands for a differentially flat system, where the flat output is chosen to be the associated state variable. Next, for each subsystem which is linked with a row of the state-space model, a virtual control input is computed, that can invert the subsystem's dynamics and can eliminate the subsystem's tracking error. From the last row of the state-space description, the control input that is actually applied to the SI engine is found. This control input contains recursively all virtual control inputs which were computed for the individual subsystems associated with the previous rows of the state-space equation. Thus, by tracing the rows of the state-space model backwards, at each iteration of the control algorithm, one can finally obtain the control input that should be applied to the SI-engine so as to assure that all its state vector elements will converge to the desirable setpoints.

  1. Prechamber equipped laser ignition for improved performance in natural gas engines

    DOE PAGES

    Almansour, Bader; Vasu, Subith; Gupta, Sreenath B.; ...

    2017-04-25

    Lean-burn operation of stationary natural gas engines offers lower NOx emissions and improved efficiency. A proven pathway to extend lean-burn operation has been to use laser ignition instead of standard spark ignition. However, under lean conditions, flame speed reduces thereby offsetting any efficiency gains resulting from the higher ratio of specific heats, γ. The reduced flame speeds, in turn, can be compensated with the use of a prechamber to result in volumetric ignition, and thereby lead to faster combustion. In this study, the optimal geometry of PCLI was identified through several tests in a single-cylinder engine as a compromise betweenmore » autoignition, NOx and soot formation within the prechamber. Subsequently, tests were conducted in a single-cylinder natural gas engine comparing the performance of three ignition systems: standard electrical spark ignition (SI), single-point laser ignition (LI), and prechamber equipped laser ignition (PCLI). Out of the three, the performance of PCLI was far superior compared to the other two. Efficiency gain of 2.1% points could be achieved while complying with EPA regulation (BSNOx < 1.34 kW-hr) and the industry standard for ignition stability (COV_IMEP < 5%). Finally, test results and data analysis are presented identifying the combustion mechanisms leading to the improved performance.« less

  2. An ignition key for atomic-scale engines.

    PubMed

    Dundas, Daniel; Cunningham, Brian; Buchanan, Claire; Terasawa, Asako; Paxton, Anthony T; Todorov, Tchavdar N

    2012-10-10

    A current-carrying resonant nanoscale device, simulated by non-adiabatic molecular dynamics, exhibits sharp activation of non-conservative current-induced forces with bias. The result, above the critical bias, is generalized rotational atomic motion with a large gain in kinetic energy. The activation exploits sharp features in the electronic structure, and constitutes, in effect, an ignition key for atomic-scale motors. A controlling factor for the effect is the non-equilibrium dynamical response matrix for small-amplitude atomic motion under current. This matrix can be found from the steady-state electronic structure by a simpler static calculation, providing a way to detect the likely appearance, or otherwise, of non-conservative dynamics, in advance of real-time modelling.

  3. Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation

    DOE PAGES

    Krisman, Alex; Hawkes, Evatt R.; Talei, Mohsen; ...

    2016-08-30

    With the goal of providing a more detailed fundamental understanding of ignition processes in diesel engines, this study reports analysis of a direct numerical simulation (DNS) database. In the DNS, a pseudo turbulent mixing layer of dimethyl ether (DME) at 400 K and air at 900 K is simulated at a pressure of 40 atmospheres. At these conditions, DME exhibits a two-stage ignition and resides within the negative temperature coefficient (NTC) regime of ignition delay times, similar to diesel fuel. The analysis reveals a complex ignition process with several novel features. Autoignition occurs as a distributed, two-stage event. The high-temperaturemore » stage of ignition establishes edge flames that have a hybrid premixed/autoignition flame structure similar to that previously observed for lifted laminar flames at similar thermochemical conditions. In conclusion, a combustion mode analysis based on key radical species illustrates the multi-stage and multi-mode nature of the ignition process and highlights the substantial modelling challenge presented by diesel combustion.« less

  4. Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation

    SciTech Connect

    Krisman, Alex; Hawkes, Evatt R.; Talei, Mohsen; Bhagatwala, Ankit; Chen, Jacqueline H.

    2016-08-30

    With the goal of providing a more detailed fundamental understanding of ignition processes in diesel engines, this study reports analysis of a direct numerical simulation (DNS) database. In the DNS, a pseudo turbulent mixing layer of dimethyl ether (DME) at 400 K and air at 900 K is simulated at a pressure of 40 atmospheres. At these conditions, DME exhibits a two-stage ignition and resides within the negative temperature coefficient (NTC) regime of ignition delay times, similar to diesel fuel. The analysis reveals a complex ignition process with several novel features. Autoignition occurs as a distributed, two-stage event. The high-temperature stage of ignition establishes edge flames that have a hybrid premixed/autoignition flame structure similar to that previously observed for lifted laminar flames at similar thermochemical conditions. In conclusion, a combustion mode analysis based on key radical species illustrates the multi-stage and multi-mode nature of the ignition process and highlights the substantial modelling challenge presented by diesel combustion.

  5. Characterisation of two-stage ignition in diesel engine-relevant thermochemical conditions using direct numerical simulation

    SciTech Connect

    Krisman, Alex; Hawkes, Evatt R.; Talei, Mohsen; Bhagatwala, Ankit; Chen, Jacqueline H.

    2016-08-30

    With the goal of providing a more detailed fundamental understanding of ignition processes in diesel engines, this study reports analysis of a direct numerical simulation (DNS) database. In the DNS, a pseudo turbulent mixing layer of dimethyl ether (DME) at 400 K and air at 900 K is simulated at a pressure of 40 atmospheres. At these conditions, DME exhibits a two-stage ignition and resides within the negative temperature coefficient (NTC) regime of ignition delay times, similar to diesel fuel. The analysis reveals a complex ignition process with several novel features. Autoignition occurs as a distributed, two-stage event. The high-temperature stage of ignition establishes edge flames that have a hybrid premixed/autoignition flame structure similar to that previously observed for lifted laminar flames at similar thermochemical conditions. In conclusion, a combustion mode analysis based on key radical species illustrates the multi-stage and multi-mode nature of the ignition process and highlights the substantial modelling challenge presented by diesel combustion.

  6. Development of a phenomenological cycle simulation for a natural gas-fuelled, compression-ignited, internal combustion engine

    NASA Astrophysics Data System (ADS)

    Liu, Yafeng

    Engine cycle simulations have been developed for modeling both diesel and dual fuel combustion in compression ignition engines. The primary objective of this work was to investigate the dual fuel combustion process in an engine and to better understand the processes of ignition, flame propagation, and pollutant formation in the engine. A multizone diesel combustion model was first developed to predict the diesel combustion process and emissions for diesel fueling. A phenomenological combustion model for dual fuel operation was then developed to simulate the combustion process and emissions of a micro-pilot diesel ignition natural gas fueled engine. Coupled with the chemical equilibrium reactions for emission formation (i.e., extended Zeldovich NOx mechanism, soot formation and destruction submodeling, unburned hydrocarbon emissions submodeling), models for diesel droplet evaporation, air entrainment, cylinder heat transfer, piston work, mass flow rates, flame propagation, crevice flow, and flame quenching have been combined with a thermodynamic analysis of the engine to yield instantaneous cylinder conditions, engine performance, and emissions. Parametric and comparison studies of diesel operation, dual fuel combustion, and micro-pilot combustion have been conducted. The major conclusions that can be drawn from this work include (1) diesel evaporation and air entrainment can have significant influence on the ignition and combustion processes, (2) pressure and temperature of inlet air, compression ratio, and the start of fuel injection are important engine operating and design parameters, (3) the combustion process of the mixture of natural gas and air is dominantly premixed-combustion, and (4) the processes of crevice flow and flame quenching can have a substantial impact on the dual fuel/micro-pilot combustion and emission formation processes.

  7. Investigation of Iso-octane Ignition and Validation of a Multizone Modeling Method in an Ignition Quality Tester

    SciTech Connect

    Osecky, Eric M.; Bogin, Gregory E.; Villano, Stephanie M.; Ratcliff, Matthew A.; Luecke, Jon; Zigler, Bradley T.; Dean, Anthony M.

    2016-08-18

    An ignition quality tester was used to characterize the autoignition delay times of iso-octane. The experimental data were characterized between temperatures of 653 and 996 K, pressures of 1.0 and 1.5 MPa, and global equivalence ratios of 0.7 and 1.05. A clear negative temperature coefficient behavior was seen at both pressures in the experimental data. These data were used to characterize the effectiveness of three modeling methods: a single-zone homogeneous batch reactor, a multizone engine model, and a three-dimensional computational fluid dynamics (CFD) model. A detailed 874 species iso-octane ignition mechanism (Mehl, M.; Curran, H. J.; Pitz, W. J.; Westbrook, C. K.Chemical kinetic modeling of component mixtures relevant to gasoline. Proceedings of the European Combustion Meeting; Vienna, Austria, April 14-17, 2009) was reduced to 89 species for use in these models, and the predictions of the reduced mechanism were consistent with ignition delay times predicted by the detailed chemical mechanism across a broad range of temperatures, pressures, and equivalence ratios. The CFD model was also run without chemistry to characterize the extent of mixing of fuel and air in the chamber. The calculations predicted that the main part of the combustion chamber was fairly well-mixed at longer times (> ~30 ms), suggesting that the simpler models might be applicable in this quasi-homogeneous region. The multizone predictions, where the combustion chamber was divided into 20 zones of temperature and equivalence ratio, were quite close to the coupled CFD-kinetics results, but the calculation time was ~11 times faster than the coupled CFD-kinetics model. Although the coupled CFD-kinetics model captured the observed negative temperature coefficient behavior and pressure dependence, discrepancies remain between the predictions and the observed ignition time delays, suggesting improvements are still needed in the kinetic mechanism and/or the CFD model. This approach suggests a

  8. Investigation of Iso-octane Ignition and Validation of a Multizone Modeling Method in an Ignition Quality Tester

    DOE PAGES

    Osecky, Eric M.; Bogin, Gregory E.; Villano, Stephanie M.; ...

    2016-08-18

    An ignition quality tester was used to characterize the autoignition delay times of iso-octane. The experimental data were characterized between temperatures of 653 and 996 K, pressures of 1.0 and 1.5 MPa, and global equivalence ratios of 0.7 and 1.05. A clear negative temperature coefficient behavior was seen at both pressures in the experimental data. These data were used to characterize the effectiveness of three modeling methods: a single-zone homogeneous batch reactor, a multizone engine model, and a three-dimensional computational fluid dynamics (CFD) model. A detailed 874 species iso-octane ignition mechanism (Mehl, M.; Curran, H. J.; Pitz, W. J.; Westbrook,more » C. K.Chemical kinetic modeling of component mixtures relevant to gasoline. Proceedings of the European Combustion Meeting; Vienna, Austria, April 14-17, 2009) was reduced to 89 species for use in these models, and the predictions of the reduced mechanism were consistent with ignition delay times predicted by the detailed chemical mechanism across a broad range of temperatures, pressures, and equivalence ratios. The CFD model was also run without chemistry to characterize the extent of mixing of fuel and air in the chamber. The calculations predicted that the main part of the combustion chamber was fairly well-mixed at longer times (> ~30 ms), suggesting that the simpler models might be applicable in this quasi-homogeneous region. The multizone predictions, where the combustion chamber was divided into 20 zones of temperature and equivalence ratio, were quite close to the coupled CFD-kinetics results, but the calculation time was ~11 times faster than the coupled CFD-kinetics model. Although the coupled CFD-kinetics model captured the observed negative temperature coefficient behavior and pressure dependence, discrepancies remain between the predictions and the observed ignition time delays, suggesting improvements are still needed in the kinetic mechanism and/or the CFD model. This approach

  9. Investigation of Iso-octane Ignition and Validation of a Multizone Modeling Method in an Ignition Quality Tester

    SciTech Connect

    Osecky, Eric M.; Bogin, Gregory E.; Villano, Stephanie M.; Ratcliff, Matthew A.; Luecke, Jon; Zigler, Bradley T.; Dean, Anthony M.

    2016-08-18

    An ignition quality tester was used to characterize the autoignition delay times of iso-octane. The experimental data were characterized between temperatures of 653 and 996 K, pressures of 1.0 and 1.5 MPa, and global equivalence ratios of 0.7 and 1.05. A clear negative temperature coefficient behavior was seen at both pressures in the experimental data. These data were used to characterize the effectiveness of three modeling methods: a single-zone homogeneous batch reactor, a multizone engine model, and a three-dimensional computational fluid dynamics (CFD) model. A detailed 874 species iso-octane ignition mechanism (Mehl, M.; Curran, H. J.; Pitz, W. J.; Westbrook, C. K.Chemical kinetic modeling of component mixtures relevant to gasoline. Proceedings of the European Combustion Meeting; Vienna, Austria, April 14-17, 2009) was reduced to 89 species for use in these models, and the predictions of the reduced mechanism were consistent with ignition delay times predicted by the detailed chemical mechanism across a broad range of temperatures, pressures, and equivalence ratios. The CFD model was also run without chemistry to characterize the extent of mixing of fuel and air in the chamber. The calculations predicted that the main part of the combustion chamber was fairly well-mixed at longer times (> ~30 ms), suggesting that the simpler models might be applicable in this quasi-homogeneous region. The multizone predictions, where the combustion chamber was divided into 20 zones of temperature and equivalence ratio, were quite close to the coupled CFD-kinetics results, but the calculation time was ~11 times faster than the coupled CFD-kinetics model. Although the coupled CFD-kinetics model captured the observed negative temperature coefficient behavior and pressure dependence, discrepancies remain between the predictions and the observed ignition time delays, suggesting improvements are still needed in the kinetic mechanism and/or the CFD model. This approach suggests a

  10. Gasoline surrogate modeling of gasoline ignition in a rapid compression machine and comparison to experiments

    SciTech Connect

    Mehl, M; Kukkadapu, G; Kumar, K; Sarathy, S M; Pitz, W J; Sung, S J

    2011-09-15

    The use of gasoline in homogeneous charge compression ignition engines (HCCI) and in duel fuel diesel - gasoline engines, has increased the need to understand its compression ignition processes under engine-like conditions. These processes need to be studied under well-controlled conditions in order to quantify low temperature heat release and to provide fundamental validation data for chemical kinetic models. With this in mind, an experimental campaign has been undertaken in a rapid compression machine (RCM) to measure the ignition of gasoline mixtures over a wide range of compression temperatures and for different compression pressures. By measuring the pressure history during ignition, information on the first stage ignition (when observed) and second stage ignition are captured along with information on the phasing of the heat release. Heat release processes during ignition are important because gasoline is known to exhibit low temperature heat release, intermediate temperature heat release and high temperature heat release. In an HCCI engine, the occurrence of low-temperature and intermediate-temperature heat release can be exploited to obtain higher load operation and has become a topic of much interest for engine researchers. Consequently, it is important to understand these processes under well-controlled conditions. A four-component gasoline surrogate model (including n-heptane, iso-octane, toluene, and 2-pentene) has been developed to simulate real gasolines. An appropriate surrogate mixture of the four components has been developed to simulate the specific gasoline used in the RCM experiments. This chemical kinetic surrogate model was then used to simulate the RCM experimental results for real gasoline. The experimental and modeling results covered ultra-lean to stoichiometric mixtures, compressed temperatures of 640-950 K, and compression pressures of 20 and 40 bar. The agreement between the experiments and model is encouraging in terms of first

  11. Dual spark plug ignition system for motorcycle internal combustion engine

    SciTech Connect

    Hoeptner, H.W.

    1991-04-02

    This patent describes an ignition system for a motorcycle two cylinder internal combustion engine, the system including magnetically coupled primary and secondary coil means, two spark plugs at each of the cylinders, a source of electrical current, and a single set of contacts controlling electrical current flow to the primary coil means for producing high voltage outputs from the secondary coil means to be delivered to all four of the spark plugs, the secondary coil means including certain secondary coil means operatively connected via the primary coil means with both the of spark plugs at one cylinder, a single cam controlling only the contacts, and a single magnetic core between the primary coil means and both the secondary coil means, and wherein the spark plugs include: two plugs at one cylinder and connected with the certain secondary coil means, two plugs at the second cylinder and connected with the other secondary coil means, the primary coil means including certain primary coil means magnetically coupled to the certain secondary coil means, and other primary coil means magnetically coupled to the other secondary coil means, the certain and other primary coil means being connected in series, electrically, the two spark plugs at one cylinder being electrically connected to opposite ends of the certain secondary coil means, and the two spark plugs at the other cylinder are electrically connected to opposite ends of the other secondary coil means. It comprises the cam driven by the engine for controlling opening of the contacts, the cam rotatable about a first axis, carrier means carrying the contacts, and adjustably rotatable about the axis.

  12. High Efficiency, Low Emissions Homogeneous Charge Compression Ignition (HCCI) Engines

    SciTech Connect

    Gravel, Roland; Maronde, Carl; Gehrke, Chris; Fiveland, Scott

    2010-10-30

    This is the final report of the High Efficiency Clean Combustion (HECC) Research Program for the U.S. Department of Energy. Work under this co-funded program began in August 2005 and finished in July 2010. The objective of this program was to develop and demonstrate a low emission, high thermal efficiency engine system that met 2010 EPA heavy-duty on-highway truck emissions requirements (0.2g/bhp-hr NOx, 0.14g/bhp-hr HC and 0.01g/bhp-hr PM) with a thermal efficiency of 46%. To achieve this goal, development of diesel homogenous charge compression ignition (HCCI) combustion was the chosen approach. This report summarizes the development of diesel HCCI combustion and associated enabling technologies that occurred during the HECC program between August 2005 and July 2010. This program showed that although diesel HCCI with conventional US diesel fuel was not a feasible means to achieve the program objectives, the HCCI load range could be increased with a higher volatility, lower cetane number fuel, such as gasoline, if the combustion rate could be moderated to avoid excessive cylinder pressure rise rates. Given the potential efficiency and emissions benefits, continued research of combustion with low cetane number fuels and the effects of fuel distillation are recommended. The operation of diesel HCCI was only feasible at part-load due to a limited fuel injection window. A 4% fuel consumption benefit versus conventional, low-temperature combustion was realized over the achievable operating range. Several enabling technologies were developed under this program that also benefited non-HCCI combustion. The development of a 300MPa fuel injector enabled the development of extended lifted flame combustion. A design methodology for minimizing the heat transfer to jacket water, known as precision cooling, will benefit conventional combustion engines, as well as HCCI engines. An advanced combustion control system based on cylinder pressure measurements was developed. A Well

  13. Coil-On-Plug Ignition for LOX/Methane Liquid Rocket Engines in Thermal Vacuum Environments

    NASA Technical Reports Server (NTRS)

    Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

    2017-01-01

    A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX) / liquid methane rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/methane propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. In order to successfully demonstrate ignition reliability in the vacuum conditions and eliminate corona discharge issues, a coil-on-plug ignition system has been developed. The ICPTA uses spark-plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark-plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp.-2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, Plum Brook testing demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/methane propulsion systems in future spacecraft.

  14. Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

    NASA Technical Reports Server (NTRS)

    Thomas, Matthew E.; Bossard, John A.; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

    2001-01-01

    The fiber optically coupled laser ignition approach summarized is under consideration for use in igniting bi-propellant rocket thrust chambers. This laser ignition approach is based on a novel dual pulse format capable of effectively increasing laser generated plasma life times up to 1000 % over conventional laser ignition methods. In the dual-pulse format tinder consideration here an initial laser pulse is used to generate a small plasma kernel. A second laser pulse that effectively irradiates the plasma kernel follows this pulse. Energy transfer into the kernel is much more efficient because of its absorption characteristics thereby allowing the kernel to develop into a much more effective ignition source for subsequent combustion processes. In this research effort both single and dual-pulse formats were evaluated in a small testbed rocket thrust chamber. The rocket chamber was designed to evaluate several bipropellant combinations. Optical access to the chamber was provided through small sapphire windows. Test results from gaseous oxygen (GOx) and RP-1 propellants are presented here. Several variables were evaluated during the test program, including spark location, pulse timing, and relative pulse energy. These variables were evaluated in an effort to identify the conditions in which laser ignition of bi-propellants is feasible. Preliminary results and analysis indicate that this laser ignition approach may provide superior ignition performance relative to squib and torch igniters, while simultaneously eliminating some of the logistical issues associated with these systems. Further research focused on enhancing the system robustness, multiplexing, and window durability/cleaning and fiber optic enhancements is in progress.

  15. Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

    NASA Technical Reports Server (NTRS)

    Thomas, Matthew E.; Bossard, John A.; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

    2001-01-01

    The fiber optically coupled laser ignition approach summarized is under consideration for use in igniting bi-propellant rocket thrust chambers. This laser ignition approach is based on a novel dual pulse format capable of effectively increasing laser generated plasma life times up to 1000 % over conventional laser ignition methods. In the dual-pulse format tinder consideration here an initial laser pulse is used to generate a small plasma kernel. A second laser pulse that effectively irradiates the plasma kernel follows this pulse. Energy transfer into the kernel is much more efficient because of its absorption characteristics thereby allowing the kernel to develop into a much more effective ignition source for subsequent combustion processes. In this research effort both single and dual-pulse formats were evaluated in a small testbed rocket thrust chamber. The rocket chamber was designed to evaluate several bipropellant combinations. Optical access to the chamber was provided through small sapphire windows. Test results from gaseous oxygen (GOx) and RP-1 propellants are presented here. Several variables were evaluated during the test program, including spark location, pulse timing, and relative pulse energy. These variables were evaluated in an effort to identify the conditions in which laser ignition of bi-propellants is feasible. Preliminary results and analysis indicate that this laser ignition approach may provide superior ignition performance relative to squib and torch igniters, while simultaneously eliminating some of the logistical issues associated with these systems. Further research focused on enhancing the system robustness, multiplexing, and window durability/cleaning and fiber optic enhancements is in progress.

  16. A Description and Test Results of a Spark-Ignition and a Compression-Ignition 2-Stroke-Cycle Engine

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Whitney, E G

    1935-01-01

    This report presents performance results of air cooled and water-cooled engines. The results obtained were sufficiently promising to warrant further investigation with fuel injection and spark ignition, with the same arrangement of inlet ports and exhaust valves at the bottom of the cylinder and the exhaust gases discharged through two poppet valves in the cylinder head. The displacement of the engine was 118 cubic inches. Optimum performance was obtained with the inlet air directed into the cylinder at an angle of 20 degrees to the radial.

  17. Chemical Kinetic Modeling of HMX and TATB Laser Ignition Tests

    SciTech Connect

    Tarver, C M

    2004-03-02

    Recent laser ignition experiments on octahydro-1,3,5,7-tetranitro-1,3,5,7-terrazocine (HMX) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) subjected to laser fluxes ranging from 10 to 800 W/cm{sup 2} produced ignition times from seconds to milliseconds. Global chemical kinetic thermal decomposition models for HMX and TATB have been developed to calculate times to thermal explosion for experiments in the seconds to days time frame. These models are applied to the laser ignition experimental data in this paper. Excellent agreement was obtained for TATB, while the calculated ignition times were longer than experiment for HMX at lower laser fluxes. At the temperatures produced in the laser experiments, HMX melts. Melting generally increases condensed phase reaction rates so faster rates were used for three of the HMX reaction rates. This improved agreement with experiments at the lower laser fluxes but yielded very fast ignition at high fluxes. The calculated times to ignition are in reasonable agreement with the laser ignition experiments, and this justifies the use of these models for estimating reaction times at impact and shock ''hot spot'' temperatures.

  18. Multi-location laser ignition using a spatial light modulator towards improving automotive gasoline engine performance

    NASA Astrophysics Data System (ADS)

    Kuang, Zheng; Lyon, Elliott; Cheng, Hua; Page, Vincent; Shenton, Tom; Dearden, Geoff

    2017-03-01

    We report on a study into multi-location laser ignition (LI) with a Spatial Light Modulator (SLM), to improve the performance of a single cylinder automotive gasoline engine. Three questions are addressed: i/ How to deliver a multi-beam diffracted pattern into an engine cylinder, through a small opening, while avoiding clipping? ii/ How much incident energy can a SLM handle (optical damage threshold) and how many simultaneous beam foci could thus be created? ; iii/ Would the multi-location sparks created be sufficiently intense and stable to ignite an engine and, if so, what would be their effect on engine performance compared to single-location LI? Answers to these questions were determined as follows. Multi-beam diffracted patterns were created by applying computer generated holograms (CGHs) to the SLM. An optical system for the SLM was developed via modelling in ZEMAX, to cleanly deliver the multi-beam patterns into the combustion chamber without clipping. Optical damage experiments were carried out on Liquid Crystal on Silicon (LCoS) samples provided by the SLM manufacturer and the maximum safe pulse energy to avoid SLM damage found to be 60 mJ. Working within this limit, analysis of the multi-location laser induced sparks showed that diffracting into three identical beams gave slightly insufficient energy to guarantee 100% sparking, so subsequent engine experiments used 2 equal energy beams laterally spaced by 4 mm. The results showed that dual-location LI gave more stable combustion and higher engine power output than single-location LI, for increasingly lean air-fuel mixtures. The paper concludes by a discussion of how these results may be exploited.

  19. High-Fidelity Simulation and Analysis of Ignition Regimes and Mixing Characteristics for Low Temperature Combustion Engine Application

    NASA Astrophysics Data System (ADS)

    Gupta, Saurabh

    Computational singular perturbation (CSP) technique is applied as an automated diagnostic tool to classify ignition regimes, especially spontaneous ignition front and deflagration in low temperature combustion (LTC) engine environments. Various model problems representing LTC are simulated using high-fidelity computation with detailed chemistry for hydrogen-air, and the simulation data are then analyzed by CSP. The active reaction zones are first identified by the locus of minimum number of fast exhausted time scales. Subsequently, the relative importance of transport and chemistry is determined in the region ahead of the reaction zone. A new index IT, defined as the sum of the absolute values of the importance indices of diffusion and convection of temperature to the slow dynamics of temperature, serves as a criterion to differentiate spontaneous ignition from deflagration regimes. The same strategy is then used to gain insights into classification of ignition regimes in n-heptane air mixtures. Parametric studies are conducted using high-fidelity simulations with detailed chemistry and transport. The mixture at non-NTC conditions shows initially a deflagration front which is subsequently transitioned into a spontaneous ignition front. For the mixtures at the NTC conditions which exhibit two-stage ignition behavior, the 1 st stage ignition front is found to be more likely in the deflagration regime. On the other hand, the 2nd stage ignition front occurs almost always in the spontaneous regime because the upstream mixture contains active radical species produced by the preceding 1st stage ignition front. The effects of differently correlated equivalence ratio stratification are also considered and the results are shown to be consistent with previous findings. 2D turbulent auto-ignition problems corresponding to NTC and non-NTC chemistry yield similar qualitative results. Finally, we look into the modeling of turbulent mixing, in particular, the

  20. The Application of High Energy Ignition and Boosting/Mixing Technology to Increase Fuel Economy in Spark Ignition Gasoline Engines by Increasing EGR Dilution Capability

    SciTech Connect

    Keating, Edward; Gough, Charles

    2015-07-07

    This report summarizes activities conducted in support of the project “The Application of High Energy Ignition and Boosting/Mixing Technology to Increase Fuel Economy in Spark Ignition Gasoline Engines by Increasing EGR Dilution Capability” under COOPERATIVE AGREEMENT NUMBER DE-EE0005654, as outlined in the STATEMENT OF PROJECT OBJECTIVES (SOPO) dated May 2012.

  1. A Preliminary Motion-picture Study of Combustion in a Compression-ignition Engine

    NASA Technical Reports Server (NTRS)

    Buckley, E C; Waldron, C D

    1934-01-01

    Motion pictures were taken at 1,850 frames per second of the spray penetration and combustion occurring in the N.A.C.A. combustion apparatus arranged to operate as a compression-ignition engine. Indicator cards were taken simultaneously with the motion pictures by means of the N.A.C.A. optical indicator. The motion pictures showed that when ignition occurred during injection it started in the spray envelope. If ignition occurred after injection cut-off, however, and after considerable mixing had taken place, it was impossible to predict where the ignition would start. The pictures also showed that ignition usually started at several points in the combustion chamber. With this apparatus, as the injection advance angle increased from 0 degrees to 40 degrees before top center, the rate of flame spread increased and the duration of the burning decreased.

  2. Ignition Study on a Rotary-valved Air-breathing Pulse Detonation Engine

    NASA Astrophysics Data System (ADS)

    Wu, Yuwen; Han, Qixiang; Shen, Yujia; Zhao, Wei

    2017-05-01

    In the present study, the ignition effect on detonation initiation was investigated in the air-breathing pulse detonation engine. Two kinds of fuel injection and ignition methods were applied. For one method, fuel and air was pre-mixed outside the PDE and then injected into the detonation tube. The droplet sizes of mixtures were measured. An annular cavity was used as the ignition section. For the other method, fuel-air mixtures were mixed inside the PDE, and a pre-combustor was utilized as the ignition source. At firing frequency of 20 Hz, transition to detonation was obtained. Experimental results indicated that the ignition position and initial flame acceleration had important effects on the deflagration-to-detonation transition.

  3. Impact of Formaldehyde Addition on Auto-Ignition in Internal-Combustion Engines

    NASA Astrophysics Data System (ADS)

    Kuwahara, Kazunari; Ando, Hiromitsu; Furutani, Masahiro; Ohta, Yasuhiko

    By employing a direct-injection diesel engine equipped with a common-rail type of injection system, by adding formaldehyde (CH2O) to the intake air, and by changing the fuel-injection timing, the compression ratio and the intake-air temperature, a mechanism for CH2O as a fuel additive to affect auto-ignition was discussed. Unlike an HCCI type of engine, the diesel engine can expose an air-fuel mixture only to a limited range of the in-cylinder temperature before the ignition, and can separate low- and high-temperature parts of the mechanism. When low-temperature oxidation starts at a temperature above 900K, there are cases that the CH2O advances the ignition timing. Below 900K, to the contrary, it always retards the timing. It is because, above 900K, a part of the CH2O changes into CO together with H2O2 as an ignition promoter. Below 900K, on the other hand, the CH2O itself acts as an OH radical scavenger against cool-flame reaction, from the beginning of low-temperature oxidation. Then, the engine was modified for its extraordinary function as a gasoline-knocking generator, in order that an effect of CH2O on knocking could be discussed. The CH2O retards the onset of auto-ignition of an end gas. Judging from a large degree of the retardation, the ignition is probably triggered below 900K.

  4. Nitrogen oxide reduction strategies for compression ignition engines

    NASA Astrophysics Data System (ADS)

    Chapman, Elana M.

    2008-05-01

    The scope of this investigation is to explore strategies to reduce NOx emissions from compression ignition engines. Two methods are presented in this collection of studies: (1) NOx reduction accomplished through a change in fuel formulation, specifically through a change in the saturated fuel carbon chains of biodiesel; and (2) NOx reduction accomplished through a mixed mode combustion process utilizing a fumigated fuel and a pilot injection of diesel fuel. In the first study, a light duty diesel engine was used to investigate the change in saturation of a biodiesel fuel and its impact on NOx emissions. Previous studies have shown that a reduction in the iodine value of a biodiesel fuel produces a reduction in NOx emissions. The iodine value of the fuel is reduced through the saturation of the C18 molecules via hydrogenation of biodiesel fuel. Experiments were performed at several speeds and loads without exhaust gas recirculation (EGR), and a NOx reduction with the hydrogenated diesel fuel was observed. For all the modes studied, the NOx emission was higher for the biodiesel and lower for the hydrogenated biodiesel in comparison to the ultra low sulfur diesel (ULSD) fuel. Results from the calculation of the adiabatic flame temperature shows that the results could be explained by the difference in adiabatic flame temperature of the fuel, thus influencing the prompt NOx contribution in addition to the thermal contribution. Since the adiabatic flame temperatures are similar for the hydrogenated biodiesel and the ULSD, yet the NOx reduction with the hydrogenated biodiesel is much lower than the ULSD levels, another explanation for the reduction is suggested: the additional prompt NOx contribution from the change in fuel chemistry. The second study investigated the NOx reductions which could be achieved with a mixed mode combustion process utilizing a fumigated fuel and a pilot injection of diesel fuel. In this research, the fumigated fuel was dimethyl ether (DME) and

  5. A reduced mechanism for biodiesel surrogates with low temperature chemistry for compression ignition engine applications

    NASA Astrophysics Data System (ADS)

    Luo, Zhaoyu; Plomer, Max; Lu, Tianfeng; Som, Sibendu; Longman, Douglas E.

    2012-04-01

    Biodiesel is a promising alternative fuel for compression ignition (CI) engines. It is a renewable energy source that can be used in these engines without significant alteration in design. The detailed chemical kinetics of biodiesel is however highly complex. In the present study, a skeletal mechanism with 123 species and 394 reactions for a tri-component biodiesel surrogate, which consists of methyl decanoate, methyl 9-decanoate and n-heptane was developed for simulations of 3-D turbulent spray combustion under engine-like conditions. The reduction was based on an improved directed relation graph (DRG) method that is particularly suitable for mechanisms with many isomers, followed by isomer lumping and DRG-aided sensitivity analysis (DRGASA). The reduction was performed for pressures from 1 to 100 atm and equivalence ratios from 0.5 to 2 for both extinction and ignition applications. The initial temperatures for ignition were from 700 to 1800 K. The wide parameter range ensures the applicability of the skeletal mechanism under engine-like conditions. As such the skeletal mechanism is applicable for ignition at both low and high temperatures. Compared with the detailed mechanism that consists of 3299 species and 10806 reactions, the skeletal mechanism features a significant reduction in size while still retaining good accuracy and comprehensiveness. The validations of ignition delay time, flame lift-off length and important species profiles were also performed in 3-D engine simulations and compared with the experimental data from Sandia National Laboratories under CI engine conditions.

  6. Ignition of pyrophoric powders: An entry-level model

    NASA Astrophysics Data System (ADS)

    Alymov, M. I.; Seplyarskii, B. S.; Gordopolova, I. S.

    2015-11-01

    Chemically prepared metal nanopowders are normally pyrophoric, i.e. are liable to ignite spontaneously on exposure to air because of high reactivity and developed specific surface. On the other side, reliable theoretical models for spontaneous self-ignition of fine dispersed powders at room temperature have not been suggested so far. A deeper insight into the mechanism of the phenomenon would shed new light on the critical conditions for self-inflammation and thus would provide some clues for optimization of the passivation of fine dispersed powders. In this work, we formulated and analyzed an entry-level model for ignition of pyrophoric powders. Analysis of such a model in terms of the ignition theory gave the following results. Depending on the width of the reaction zone, the ignition may get started in either one or two stages. The duration of each stage was evaluated by using the approximate methods of combustion theory. The parametric limits for the model applicability were derived and the influence of sample length on the ignition process was explored as well.

  7. Homogenous charge compression ignition engine having a cylinder including a high compression space

    DOEpatents

    Agama, Jorge R.; Fiveland, Scott B.; Maloney, Ronald P.; Faletti, James J.; Clarke, John M.

    2003-12-30

    The present invention relates generally to the field of homogeneous charge compression engines. In these engines, fuel is injected upstream or directly into the cylinder when the power piston is relatively close to its bottom dead center position. The fuel mixes with air in the cylinder as the power piston advances to create a relatively lean homogeneous mixture that preferably ignites when the power piston is relatively close to the top dead center position. However, if the ignition event occurs either earlier or later than desired, lowered performance, engine misfire, or even engine damage, can result. Thus, the present invention divides the homogeneous charge between a controlled volume higher compression space and a lower compression space to better control the start of ignition.

  8. Fuel mixture stratification as a method for improving homogeneous charge compression ignition engine operation

    DOEpatents

    Dec, John E.; Sjoberg, Carl-Magnus G.

    2006-10-31

    A method for slowing the heat-release rate in homogeneous charge compression ignition ("HCCI") engines that allows operation without excessive knock at higher engine loads than are possible with conventional HCCI. This method comprises injecting a fuel charge in a manner that creates a stratified fuel charge in the engine cylinder to provide a range of fuel concentrations in the in-cylinder gases (typically with enough oxygen for complete combustion) using a fuel with two-stage ignition fuel having appropriate cool-flame chemistry so that regions of different fuel concentrations autoignite sequentially.

  9. Neural network controller development and implementation for spark ignition engines with high EGR levels.

    PubMed

    Vance, Jonathan Blake; Singh, Atmika; Kaul, Brian C; Jagannathan, Sarangapani; Drallmeier, James A

    2007-07-01

    Past research has shown substantial reductions in the oxides of nitrogen (NOx) concentrations by using 10%-25% exhaust gas recirculation (EGR) in spark ignition (SI) engines (see Dudek and Sain, 1989). However, under high EGR levels, the engine exhibits strong cyclic dispersion in heat release which may lead to instability and unsatisfactory performance preventing commercial engines to operate with high EGR levels. A neural network (NN)-based output feedback controller is developed to reduce cyclic variation in the heat release under high levels of EGR even when the engine dynamics are unknown by using fuel as the control input. A separate control loop was designed for controlling EGR levels. The stability analysis of the closed-loop system is given and the boundedness of the control input is demonstrated by relaxing separation principle, persistency of excitation condition, certainty equivalence principle, and linear in the unknown parameter assumptions. Online training is used for the adaptive NN and no offline training phase is needed. This online learning feature and model-free approach is used to demonstrate the applicability of the controller on a different engine with minimal effort. Simulation results demonstrate that the cyclic dispersion is reduced significantly using the proposed controller when implemented on an engine model that has been validated experimentally. For a single cylinder research engine fitted with a modern four-valve head (Ricardo engine), experimental results at 15% EGR indicate that cyclic dispersion was reduced 33% by the controller, an improvement of fuel efficiency by 2%, and a 90% drop in NOx from stoichiometric operation without EGR was observed. Moreover, unburned hydrocarbons (uHC) drop by 6% due to NN control as compared to the uncontrolled scenario due to the drop in cyclic dispersion. Similar performance was observed with the controller on a different engine.

  10. Propellant Flow Actuated Piezoelectric Igniter for Combustion Engines

    NASA Technical Reports Server (NTRS)

    Wollen, Mark A. (Inventor)

    2015-01-01

    A propellant flow actuated piezoelectric igniter device using one or more hammer balls retained by one or more magnets, or other retaining method, until sufficient fluid pressure is achieved to release and accelerate the hammer ball, such that it impacts a piezoelectric crystal to produce an ignition spark. Certain preferred embodiments provide a means for repetitively capturing and releasing the hammer ball after it impacts one or more piezoelectric crystals, thereby oscillating and producing multiple, repetitive ignition sparks. Furthermore, an embodiment is presented for which oscillation of the hammer ball and repetitive impact to the piezoelectric crystal is maintained without the need for a magnet or other retaining mechanism to achieve this oscillating impact process.

  11. Method for operating a spark-ignition, direct-injection internal combustion engine

    DOEpatents

    Narayanaswamy, Kushal; Koch, Calvin K.; Najt, Paul M.; Szekely, Jr., Gerald A.; Toner, Joel G.

    2015-06-02

    A spark-ignition, direct-injection internal combustion engine is coupled to an exhaust aftertreatment system including a three-way catalytic converter upstream of an NH3-SCR catalyst. A method for operating the engine includes operating the engine in a fuel cutoff mode and coincidentally executing a second fuel injection control scheme upon detecting an engine load that permits operation in the fuel cutoff mode.

  12. Theoretical and Experimental Study of Ignition Lag and Engine Knock

    NASA Technical Reports Server (NTRS)

    Schmidt, Frtiz A F

    1939-01-01

    The author believes, on the basis of experimental ignition-lag data, that the character of a fuel cannot be stated in terms of a single constant (such as octane or cetane number) but that at least two and generally three constants are required. Thus no correlation between knock ratings can be expected if in one set of tests the charge temperature was varied while in the other the charge pressure was varied. For this reason, he favors knock rating being based on an equation characterizing the ignition lag of the fuel as a function of pressure and temperature of the charge.

  13. Progress in modelling ignition implosion experiments on the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Clark, D. S.; Eder, D. C.; Haan, S. W.; Hammel, B. A.; Hinkel, D. E.; Jones, O. S.; Marinak, M. M.; Milovich, J. L.; Patel, P. K.; Salmonson, J. D.; Sepke, S. M.; Thomas, C. A.; Town, R. P. J.

    2016-03-01

    The recently completed National Ignition Campaign on the National Ignition Facility showed significant discrepancies between 2-D simulations predictions of implosion performance and experimentally measured performance, particularly in thermonuclear yield. This discrepancy between simulation and observation persisted despite concerted efforts to include all of the known sources of implosion degradation within a reasonable 2-D simulation model, e.g., using measured surface imperfections and radiation drives adjusted to reproduce observed implosion trajectories. Since this simulation study was undertaken, more recent experiments have brought to light several effects that can significantly impact implosion performance, in particular large inflight long-wavelength shell asymmetries and larger than expected perturbations seeded by the capsule support tent. These effects are now being included in the simulation model and show improved agreement with observation. In addition, full-capsule 3-D simulations with resolution adequate to model the dominant unstable hydrodynamic modes are being run and show further improvements in agreement with experiment.

  14. Reactive burn models and ignition & growth concept

    SciTech Connect

    Menikoff, Ralph S; Shaw, Milton S

    2010-01-01

    Plastic-bonded explosives are heterogeneous materials. Experimentally, shock initiation is sensitive to small amounts of porosity, due to the formation of hot spots (small localized regions of high temperature). This leads to the Ignition and Growth concept, introduced by Lee and Tarver in 1980, as the basis for reactive burn models. A homogeneized burn rate needs to account for three mesoscale physical effects (i) the density of burnt hot spots, which depends on the lead shock strength; (ii) the growth of the burn fronts triggered by hot spots, which depends on the local deflagration speed; (iii) a geometric factor that accounts for the overlap of deflagration wavelets from adjacent hot spots. These effects can be combined and the burn model defined by specifying the reaction progress variable {lambda}(t) as a function of a dimensionless reaction length {tau}{sub hs}(t)/{ell}{sub hs}, rather than by xpecifying an explicit burn rate. The length scale {ell}{sub hs} is the average distance between hot spots, which is proportional to [N{sub hs}(P{sub s})]{sup -1/3}, where N{sub hs} is the number density of hot spots activated by the lead shock. The reaction length {tau}{sub hs}(t) = {line_integral}{sub 0}{sup t} D(P(t'))dt' is the distance the burn front propagates from a single hot spot, where D is the deflagration speed and t is the time since the shock arrival. A key implementation issue is how to determine the lead shock strength in conjunction with a shock capturing scheme. They have developed a robust algorithm for this purpose based on the Hugoniot jump condition for the energy. The algorithm utilizes the time dependence of density, pressure and energy within each cell. The method is independent of the numerical dissipation used for shock capturing. It is local and can be used in one or more space dimensions. The burn model has a small number of parameters which can be calibrated to fit velocity gauge data from shock initiation experiments.

  15. Pegasus Engine Ignites after Drop from B-52 Mothership

    NASA Image and Video Library

    1991-07-17

    Against the midnight blue of a high-altitude sky, Orbital Sciences’ Pegasus winged rocket booster ignites after being dropped from NASA’s B-52 mothership on a July 1991 flight. A NASA chase plane for the flight is also visible above the rocket and below the B-52.

  16. Experimental Investigation of Piston Heat Transfer in a Light Duty Engine Under Conventional Diesel, Homogeneous Charge Compression Ignition, and Reactivity Controlled Compression Ignition Combustion Regimes

    DTIC Science & Technology

    2014-02-13

    For Official Use Only UNCLASSIFIED Experimental Investigation of Piston Heat Transfer in a Light Duty Engine Under Conventional Diesel...Now affiliated with U.S. Army TARDEC ** University of Wisconsin-Madison Sandia National Laboratory Advanced Engine Combustion Meeting February...Experimental Investigation of Piston Heat Transfer in a Light Duty Engine Under Conventional Diesel, Homogeneous Charge Compression Ignition, and Reactivity

  17. A Preliminary Study of Flame Propagation in a Spark-ignition Engine

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Spencer, R C

    1937-01-01

    The N.A.C.A. combustion apparatus was altered to operate as a fuel-injection, spark-ignition engine, and a preliminary study was made of the combustion of gasoline-air mixtures at various air-fuel ratios. Air-fuel ratios ranging from 10 to 21.6 were investigated. Records from an optical indicator and films from a high-speed motion-picture camera were the chief sources of data. Schlieren photography was used for an additional study. The results show that the altered combustion apparatus has characteristics similar to those of a conventional spark-ignition engine and should be useful in studying phenomena in spark-ignition engines. The photographs show the flame front to be irregularly shaped rather than uniformly curved. With a theoretically correct mixture the reaction, as indicated by the photographs, is not completed in the flame front but continues for some time after the combustion front has traversed the mixture.

  18. Experimental evaluation of the ignition process of carbon monoxide and oxygen in a rocket engine

    NASA Technical Reports Server (NTRS)

    Linne, Diane L.

    1996-01-01

    Carbon monoxide and oxygen ignition boundaries were determined in a spark torch igniter as a function of propellant inlet temperatures. The oxygen temperature was varied from ambient to -258 F, and the carbon monoxide temperature was varied from ambient to -241 F. With the oxygen and carbon monoxide at -253 F and -219 F, respectively, they successfully ignited between mixture ratios of 2.42 and 3.10. Analysis of the results indicated that the lower ignition boundary was more sensitive to oxygen temperature than to carbon monoxide temperature. Another series of tests was performed in a small simulated rocket engine with oxygen at -197 F and carbon monoxide at -193 F. An oxygen/hydrogen flame was used to initiate combustion of the oxygen and carbon monoxide. Tests performed at the optimum operating mixture ratio of 0.55 obtained steady-state combustion in every test.

  19. Physics-based modeling of live wildland fuel ignition experiments in the Forced Ignition and Flame Spread Test apparatus

    Treesearch

    C. Anand; B. Shotorban; S. Mahalingam; S. McAllister; D. R. Weise

    2017-01-01

    A computational study was performed to improve our understanding of the ignition of live fuel in the forced ignition and flame spread test apparatus, a setup where the impact of the heating mode is investigated by subjecting the fuel to forced convection and radiation. An improvement was first made in the physics-based model WFDS where the fuel is treated as fixed...

  20. Internal combustion engine report: Spark ignited ICE GenSet optimization and novel concept development

    SciTech Connect

    Keller, J.; Blarigan, P. Van

    1998-08-01

    In this manuscript the authors report on two projects each of which the goal is to produce cost effective hydrogen utilization technologies. These projects are: (1) the development of an electrical generation system using a conventional four-stroke spark-ignited internal combustion engine generator combination (SI-GenSet) optimized for maximum efficiency and minimum emissions, and (2) the development of a novel internal combustion engine concept. The SI-GenSet will be optimized to run on either hydrogen or hydrogen-blends. The novel concept seeks to develop an engine that optimizes the Otto cycle in a free piston configuration while minimizing all emissions. To this end the authors are developing a rapid combustion homogeneous charge compression ignition (HCCI) engine using a linear alternator for both power take-off and engine control. Targeted applications include stationary electrical power generation, stationary shaft power generation, hybrid vehicles, and nearly any other application now being accomplished with internal combustion engines.

  1. Compression-ignition Engine Performance at Altitudes and at Various Air Pressures and Temperatures

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Collins, John H

    1937-01-01

    Engine test results are presented for simulated altitude conditions. A displaced-piston combustion chamber on a 5- by 7-inch single cylinder compression-ignition engine operating at 2,000 r.p.m. was used. Inlet air temperature equivalent to standard altitudes up to 14,000 feet were obtained. Comparison between performance at altitude of the unsupercharged compression-ignition engine compared favorably with the carburetor engine. Analysis of the results for which the inlet air temperature, inlet air pressure, and inlet and exhaust pressure were varied indicates that engine performance cannot be reliably corrected on the basis of inlet air density or weight of air charge. Engine power increases with inlet air pressure and decreases with inlet air temperatures very nearly as straight line relations over a wide range of air-fuel ratios. Correction factors are given.

  2. Heat transfer model for predicting squib ignition times

    NASA Technical Reports Server (NTRS)

    Sernas, V.

    1974-01-01

    A squib ignition model based on transient heat condition from the hot bridgewire to the pyrotechnic is described. No Arrhenius-type chemical reaction is included. Instead, a thermal contact resistance is postulated to exist between the hot bridgewire and the pyrotechnic. Ignition is assumed to occur when a 2.5 micron layer of pyrotechnic next to the bridgewire reaches a characteristic ignition temperature for that pyrotechnic. This model was applied to the JPL squib, which uses a 50 micron (0.002-in.) diameter Tophet A bridgewire to ignite a boron, potassium perchlorate mix. A computer program was utilized that solves the transient heat condition problem with the boundary conditions stipulated by the model. The thermal contact conductance at the interface was determined by trial and error so that the experimentally determined ignition time for one firing condition would be properly predicted by the model. The agreement was quite good for tests run between -129 C and +93.3 C at current levels of 3.5 and 5 A. Axial heat conduction along the bridgewire is shown to be negligible.

  3. Extending operating range of a homogeneous charge compression ignition engine via cylinder deactivation

    DOEpatents

    Hergart, Carl-Anders; Hardy, William L.; Duffy, Kevin P.; Liechty, Michael P.

    2008-05-27

    An HCCI engine has the ability to operate over a large load range by utilizing a lower cetane distillate diesel fuel to increase ignition delay. This permits more stable operation at high loads by avoidance of premature combustion before top dead center. During low load conditions, a portion of the engines cylinders are deactivated so that the remaining cylinders can operate at a pseudo higher load while the overall engine exhibits behavior typical of a relatively low load.

  4. About the constructive and functional particularities of spark ignition engines with gasoline direct injection: experimental results

    NASA Astrophysics Data System (ADS)

    Niculae, M.; Ivan, F.; Neacsu, D.

    2017-08-01

    The paper aims to analyze and compare the environmental performances between a gasoline direct engine and a multi-point injection engine. There are analyzed the stages of emission formation during the New European Driving Cycle. The paper points out the dynamic, economic and environmental performances of spark ignition engines equipped with a GDI systems. Reason why, we believe the widespread implementation of this technology is today an immediate need.

  5. Extending operating range of a homogeneous charge compression ignition engine via cylinder deactivation

    DOEpatents

    Hergart, Carl-Anders [Peoria, IL; Hardy, William L [Peoria, IL; Duffy, Kevin P [Metamora, IL; Liechty, Michael P [Chillicothe, IL

    2008-05-27

    An HCCI engine has the ability to operate over a large load range by utilizing a lower cetane distillate diesel fuel to increase ignition delay. This permits more stable operation at high loads by avoidance of premature combustion before top dead center. During low load conditions, a portion of the engines cylinders are deactivated so that the remaining cylinders can operate at a pseudo higher load while the overall engine exhibits behavior typical of a relatively low load.

  6. Optical Diagnostic Equipment for Research on Critical Processes in Spark-Ignition Engines

    SciTech Connect

    Hochgreb, Simone

    1999-08-08

    The equipment requested under grant Contract No. DE-FG02-95TE00065 was used in several projects investigating the behavior of fuel in spark-ignition engines. It has been a crucial piece of these efforts in understanding how new direct-injected engine sprays behave, as well as a key part in the determination of how liquid fuel enters the engine during port-fuel injection.

  7. Over compression influence to the performances of the spark ignition engines

    NASA Astrophysics Data System (ADS)

    Rakosi, E.; Talif, S. G.; Manolache, G.

    2016-08-01

    This paper presents the theoretical and experimental results of some procedures used in improving the performances of the automobile spark ignition engines. The study uses direct injection and high over-compression applied to a standard engine. To this purpose, the paper contains both the constructive solutions and the results obtained from the test bed concerning the engine power indices, fuel consumption and exhaust emissions.

  8. A University Consortium on Homogeneous Charge Compression Ignition Engine Research

    SciTech Connect

    Assanis, Dennis; Atreya, Arvind; Bowman, Craig; Chen, Jyh-Yuan; Cheng, Wai; Davidson, David; Dibble, Robert; Edwards, Chris; Filipi, Zoran; Golden, David; Green, William; Hanson, Ronald; Hedrick, J Karl; Heywood, John; Im, Hong; Lavoie, George; Sick, Volker; Wooldridge, Margaret

    2007-03-31

    Over the course of this four year project, the consortium team members from UM, MIT, Stanford, and Berkeley along with contributors from Sandia National Labs and LLNL, have produced a wide range of results on gasoline HCCI control and implementation. The work spanned a wide range of activities including engine experiments, fundamental chemical kinetics experiments, and an array of analytical modeling techniques and simulations. Throughout the project a collaborative approach has produced a many significant new insights into HCCI engines and their behavior while at the same time we achieved our key consortium goal: to develop workable strategies for gasoline HCCI control and implementation. The major accomplishments in each task are summarized, followed by detailed discussion.

  9. Compact nanosecond laser system for the ignition of aeronautic combustion engines

    NASA Astrophysics Data System (ADS)

    Amiard-Hudebine, G.; Tison, G.; Freysz, E.

    2016-12-01

    We have studied and developed a compact nanosecond laser system dedicated to the ignition of aeronautic combustion engines. This system is based on a nanosecond microchip laser delivering 6 μJ nanosecond pulses, which are amplified in two successive stages. The first stage is based on an Ytterbium doped fiber amplifier (YDFA) working in a quasi-continuous-wave (QCW) regime. Pumped at 1 kHz repetition rate, it delivers TEM00 and linearly polarized nanosecond pulses centered at 1064 nm with energies up to 350 μJ. These results are in very good agreement with the model we specially designed for a pulsed QCW pump regime. The second amplification stage is based on a compact Nd:YAG double-pass amplifier pumped by a 400 W peak power QCW diode centered at λ = 808 nm and coupled to a 800 μm core multimode fiber. At 10 Hz repetition rate, this system amplifies the pulse delivered by the YDFA up to 11 mJ while preserving its beam profile, polarization ratio, and pulse duration. Finally, we demonstrate that this compact nanosecond system can ignite an experimental combustion chamber.

  10. Development of Augmented Spark Impinging Igniter System for Methane Engines

    NASA Technical Reports Server (NTRS)

    Marshall, William M.; Osborne, Robin J.; Greene, Sandra E.

    2017-01-01

    The Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) program is establishing multiple no-funds-exchanged Space Act Agreement (SAA) partnerships with U.S. private sector entities. The purpose of this program is to encourage the development of robotic lunar landers that can be integrated with U.S. commercial launch capabilities to deliver payloads to the lunar surface. NASA can share technology and expertise under the SAA for the benefit of the CATALYST partners. MSFC seeking to vacuum test Augmented Spark Impinging (ASI) igniter with methane and new exciter units to support CATALYST partners and NASA programs. ASI has previously been used/tested successfully at sea-level, with both O2/CH4 and O2/H2 propellants. Conventional ignition exciter systems historically experienced corona discharge issues in vacuum. Often utilized purging or atmospheric sealing on high voltage lead to remedy. Compact systems developed since PCAD could eliminate the high-voltage lead and directly couple the exciter to the spark igniter. MSFC developed Augmented Spark Impinging (ASI) igniter. Successfully used in several sea-level test programs. Plasma-assisted design. Portion of ox flow is used to generate hot plasma. Impinging flows downstream of plasma. Additional fuel flow down torch tube sleeve for cooling near stoichiometric torch flame. Testing done at NASA GRC Altitude Combustion Stand (ACS) facility 2000-lbf class facility with altitude simulation up to around 100,000 ft. (0.2 psia [10 Torr]) via nitrogen driven ejectors. Propellant conditioning systems can provide temperature control of LOX/CH4 up to test article.

  11. Ignition temperature of magnesium powder clouds: a theoretical model.

    PubMed

    Chunmiao, Yuan; Chang, Li; Gang, Li; Peihong, Zhang

    2012-11-15

    Minimum ignition temperature of dust clouds (MIT-DC) is an important consideration when adopting explosion prevention measures. This paper presents a model for determining minimum ignition temperature for a magnesium powder cloud under conditions simulating a Godbert-Greenwald (GG) furnace. The model is based on heterogeneous oxidation of metal particles and Newton's law of motion, while correlating particle size, dust concentration, and dust dispersion pressure with MIT-DC. The model predicted values in close agreement with experimental data and is especially useful in predicting temperature and velocity change as particles pass through the furnace tube.

  12. LES FOR SIMULATING THE GAS EXCHANGE PROCESS IN A SPARK IGNITION ENGINE

    SciTech Connect

    Ameen, Muhsin M; yang, xiaofeng; kuo, tang-wei; Xue, Qingluan; Som, Sibendu

    2015-01-01

    The gas exchange process is known to be a significant source of cyclic variability in Internal Combustion Engines (ICE). Traditionally, Large Eddy Simulations (LES) are expected to capture these cycle-to-cycle variations. This paper reports a numerical effort to establish best practices for capturing cyclic variability with LES tools in a Transparent Combustion Chamber (TCC) spark ignition engine. The main intention is to examine the sensitivity of cycle averaged mean and Root Mean Square (RMS) flow fields and Proper Orthogonal Decomposition (POD) modes to different computational hardware, adaptive mesh refinement (AMR) and LES sub-grid scale (SGS) models, since these aspects have received little attention in the past couple of decades. This study also examines the effect of near-wall resolution on the predicted wall shear stresses. LES is pursued with commercially available CONVERGE code. Two different SGS models are tested, a one-equation eddy viscosity model and dynamic structure model. The results seem to indicate that both mean and RMS fields without any SGS model are not much different than those with LES models, either one-equation eddy viscosity or dynamic structure model. Computational hardware results in subtle quantitative differences, especially in RMS distributions. The influence of AMR on both mean and RMS fields is negligible. The predicted shear stresses near the liner walls is also found to be relatively insensitive to near-wall resolution except in the valve curtain region.

  13. A Comparison of Ignition Characteristics of Diesel Fuels as Determined in Engines and in a Constant-volume Bomb

    NASA Technical Reports Server (NTRS)

    Selden, Robert F

    1939-01-01

    Ignition-lag data have been obtained for seven fuels injected into heated, compressed air under conditions simulating those in a compression-ignition engine. The results of the bomb tests have been compared with similar engine data, and the differences between the two sets of results are explained in terms of the response of each fuel to variations in air density and temperature.

  14. Thermodynamic analysis of turbulent combustion in a spark ignition engine. Experimental evidence

    NASA Technical Reports Server (NTRS)

    Beretta, G. P.; Rashidi, M.; Keck, J. C.

    1980-01-01

    A method independent of physical modeling assumptions is presented to analyze high speed flame photography and cylinder pressure measurements from a transparent piston spark ignition research engine. The method involves defining characteristic quantities of the phenomena of flame propagation and combustion, and estimating their values from the experimental information. Using only the pressure information, the mass fraction curves are examined. An empirical burning law is presented which simulates such curves. Statistical data for the characteristics delay and burning angles which show that cycle to cycle fractional variations are of the same order of magnitude for both angles are discussed. The enflamed and burnt mass fractions are compared as are the rates of entrainment and burning.

  15. A Preliminary Study of Fuel Injection and Compression Ignition as Applied to an Aircraft Engine Cylinder

    NASA Technical Reports Server (NTRS)

    Gardiner, Arthur W

    1927-01-01

    This report summarizes some results obtained with a single cylinder test engine at the Langley Field Laboratory during a preliminary investigation of the problem of applying fuel injection and compression ignition to aircraft engines. For this work a standard Liberty Engine cylinder was fitted with a high compression, 11.4 : 1 compression ratio, piston, and equipped with an airless injection system, including a primary fuel pump, an injection pump, and an automatic injection valve. The results obtained during this investigation have indicated the possibility of applying airless injection and compression ignition to a cylinder of this size, 8-inch bore by 7-inch stroke, when operating at engine speeds as high as 1,850 R. P. M. A minimum specific fuel consumption with diesel engine fuel oil of 0.30 pound per I. HP. Hour was obtained when developing about 16 B. HP. At 1,730 R. P. M.

  16. Fuel Vaporization and Its Effect on Combustion in a High-Speed Compression-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Waldron, C D

    1933-01-01

    The tests discussed in this report were conducted to determine whether or not there is appreciable vaporization of the fuel injected into a high-speed compression-ignition engine during the time available for injection and combustion. The effects of injection advance angle and fuel boiling temperature were investigated. The results show that an appreciable amount of the fuel is vaporized during injection even though the temperature and pressure conditions in the engine are not sufficient to cause ignition either during or after injection, and that when the conditions are such as to cause ignition the vaporization process affects the combustion. The results are compared with those of several other investigators in the same field.

  17. Modeling of homogeneous charge compression ignition (HCCI) of methane

    SciTech Connect

    Smith, J.R.; Aceves, S.M.; Westbrook, C.; Pitz, W.

    1997-05-01

    The operation of piston engines on a compression ignition cycle using a lean, homogeneous charge has many potential attractive features. These include the potential for extremely low NO{sub x} and particulate emissions while maintaining high thermal efficiency and not requiring the expensive high pressure injection system of the typical modem diesel engine. Using the HCT chemical kinetics code to simulate autoignition of methane-air mixtures, we have explored the ignition timing, burn duration, NO{sub x} production, indicated efficiency and power output of an engine with a compression ratio of 15:1 at 1200 and 2400 rpm. HCT was modified to include the effects of heat transfer. This study used a single control volume reaction zone that varies as a function of crank angle. The ignition process is controlled by varying the intake equivalence ratio and varying the residual gas trapping (RGT). RGT is internal exhaust gas recirculation which recycles both heat and combustion product species. It is accomplished by varying the timing of the exhaust valve closure. Inlet manifold temperature was held constant at 330 Kelvins. Results show that there is a narrow range of operational conditions that show promise of achieving the control necessary to vary power output while keeping indicated efficiency above 50% and NO{sub x} levels below 100 ppm.

  18. Two stroke homogenous charge compression ignition engine with pulsed air supplier

    DOEpatents

    Clarke, John M.

    2003-08-05

    A two stroke homogenous charge compression ignition engine includes a volume pulsed air supplier, such as a piston driven pump, for efficient scavenging. The usage of a homogenous charge tends to decrease emissions. The use of a volume pulsed air supplier in conjunction with conventional poppet type intake and exhaust valves results in a relatively efficient scavenging mode for the engine. The engine preferably includes features that permit valving event timing, air pulse event timing and injection event timing to be varied relative to engine crankshaft angle. The principle use of the invention lies in improving diesel engines.

  19. IMPROVEMENT TO PIPELINE COMPRESSOR ENGINE RELIABILITY THROUGH RETROFIT MICRO-PILOT IGNITION SYSTEM

    SciTech Connect

    Scott Chase; Daniel Olsen; Ted Bestor

    2005-05-01

    This report documents a 3-year research program conducted by the Engines & Energy Conversion Laboratory (EECL) at Colorado State University (CSU) to develop micropilot ignition systems for existing pipeline compressor engines. Research activities for the overall program were conducted with the understanding that the efforts are to result in a commercial product to capture and disseminate the efficiency and environmental benefits of this new technology. An extensive state-of-art review was conducted to leverage the existing body of knowledge of micropilot ignition with respect to retrofit applications. Additionally, commercially-available fuel injection products were identified and applied to the program where appropriate. This approach will minimize the overall time-to-market requirements, while meeting performance and cost criteria. The objective for Phase I was to demonstrate the feasibility of micropilot ignition for large bore, slow speed engines operating at low compression ratios under laboratory conditions at the EECL. The primary elements of Micropilot Phase I were to develop a single-cylinder test chamber to study the injection of pilot fuel into a combustion cylinder and to develop, install and test a multi-cylinder micropilot ignition system for a 4-cylinder, natural gas test engine. In all, there were twelve (12) tasks defined and executed to support these two (2) primarily elements in a stepwise fashion. Task-specific approaches and results are documented in this report. The four-cylinder prototype data was encouraging for the micro-pilot ignition technology when compared to spark ignition. The objective for Phase II was to further develop and optimize the micropilot ignition system at the EECL for large bore, slow speed engines operating at low compression ratios. The primary elements of Micropilot Phase II were to evaluate the results for the 4-cylinder system prototype developed for Phase I, then optimize this system and prepare the technology for

  20. Compression-ignition engine performance with undoped and doped fuel oils and alcohol mixtures

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Foster, Hampton H

    1939-01-01

    Several fuel oils, doped fuel oils, and mixtures of alcohol and fuel oil were tested in a high-speed, single-cylinder, compression-ignition engine to determine power output, fuel consumption, and ignition and combustion characteristics. Fuel oils or doped fuel oils of high octane number had shorter ignition lags, lower rates of pressure rise, and gave smoother engine operation than fuel oils or doped fuel oils of low octane number. Higher engine rotative speeds and boost pressures resulted in smoother engine operation and permitted the use of fuel oils of relatively low octane number. Although the addition of a dope to a fuel oil decreased the ignition lag and the rate of pressure rise, the ensuing rate of combustion was somewhat slower than for the undoped fuel oil so that the effectiveness of combustion was practically unchanged. Alcohol used as an auxiliary fuel, either as a mixture or by separate injection, increased the rates of pressure rise and induced roughness. In general, the power output decreased as the proportion of alcohol increased and, below maximum power, varied with the heating value of the total fuel charge.

  1. Illustrations for a Competency Based Curriculum Guide: Ethanol Spark Ignition Engine Conversion.

    ERIC Educational Resources Information Center

    Illinois State Board of Education, Springfield. Dept. of Adult, Vocational and Technical Education.

    This document contains 56 illustrations for use in an Illinois-developed competency-based course in ethanol spark ignition engine conversion. Each illustration is related to a specific competency in the course curriculum guide. Illustrations, which include photographs and line drawings, cover some of the following topics: carburetion, compression,…

  2. Illustrations for a Competency Based Curriculum Guide: Ethanol Spark Ignition Engine Conversion.

    ERIC Educational Resources Information Center

    Illinois State Board of Education, Springfield. Dept. of Adult, Vocational and Technical Education.

    This document contains 56 illustrations for use in an Illinois-developed competency-based course in ethanol spark ignition engine conversion. Each illustration is related to a specific competency in the course curriculum guide. Illustrations, which include photographs and line drawings, cover some of the following topics: carburetion, compression,…

  3. Analysis of Homogeneous Charge Compression Ignition (HCCI) Engines for Cogeneration Applications

    SciTech Connect

    Aceves, S; Martinez-Frias, J; Reistad, G

    2004-04-30

    This paper presents an evaluation of the applicability of Homogeneous Charge Compression Ignition Engines (HCCI) for small-scale cogeneration (less than 1 MWe) in comparison to five previously analyzed prime movers. The five comparator prime movers include stoichiometric spark-ignited (SI) engines, lean burn SI engines, diesel engines, microturbines and fuel cells. The investigated option, HCCI engines, is a relatively new type of engine that has some fundamental differences with respect to other prime movers. Here, the prime movers are compared by calculating electric and heating efficiency, fuel consumption, nitrogen oxide (NOx) emissions and capital and fuel cost. Two cases are analyzed. In Case 1, the cogeneration facility requires combined power and heating. In Case 2, the requirement is for power and chilling. The results show that the HCCI engines closely approach the very high fuel utilization efficiency of diesel engines without the high emissions of NOx and the expensive diesel fuel. HCCI engines offer a new alternative for cogeneration that provides a unique combination of low cost, high efficiency, low emissions and flexibility in operating temperatures that can be optimally tuned for cogeneration systems. HCCI engines are the most efficient technology that meets the oncoming 2007 CARB NOx standards for cogeneration engines. The HCCI engine appears to be a good option for cogeneration systems and merits more detailed analysis and experimental demonstration.

  4. FIREBALL: Fusion Ignition Rocket Engine with Ballistic Ablative Lithium Liner

    SciTech Connect

    Martin, Adam K.; Eskridge, Richard H.; Lee, Michael H.; Fimognari, Peter J.

    2006-01-20

    Thermo-nuclear fusion may be the key to a high Isp, high specific power propulsion system. In a fusion system energy is liberated within, and imparted directly to, the propellant. In principle, this can overcome the performance limitations inherent in systems that require thermal power transfer across a material boundary, and/or multiple power conversion stages (NTR, NEP). A thermo-nuclear propulsion system, which attempts to overcome some of the problems inherent in the Orion concept, is described. A dense FRC plasmoid is accelerated to high velocity (in excess of 500 km/s) and is compressed into a detached liner (pulse unit). The kinetic energy of the FRC is converted into thermal and magnetic-field energy, igniting a fusion burn in the magnetically confined plasma. The fusion reaction serves as an ignition source for the liner, which is made out of detonable materials. The energy liberated in this process is converted to thrust by a pusher-plate, as in the classic Orion concept. However with this concept, the vehicle does not carry a magazine of autonomous pulse-units. By accelerating a second, heavier FRC, which acts as a piston, right behind the first one, the velocity required to initiate the fusion burn is greatly reduced.

  5. IMPROVEMENT TO PIPELINE COMPRESSOR ENGINE RELIABILITY THROUGH RETROFIT MICRO-PILOT IGNITION SYSTEM-PHASE I

    SciTech Connect

    Ted Bestor

    2003-03-04

    This report documents the first year's effort towards a 3-year program to develop micropilot ignition systems for existing pipeline compressor engines. In essence, all Phase I goals and objectives were met. We intend to proceed with the Phase II research plan, as set forth by the applicable Research Management Plan. The objective for Phase I was to demonstrate the feasibility of micropilot ignition for large bore, slow speed engines operating at low compression ratios. The primary elements of Micropilot Phase I were to develop a single-cylinder test chamber to study the injection of pilot fuel into a combustion cylinder and to develop, install and test a multi-cylinder micropilot ignition system for a 4-cylinder, natural gas test engine. In all, there were twelve (12) tasks defined and executed to support these two (2) primarily elements in a stepwise fashion. Task-specific approaches and results are documented in this report. Research activities for Micropilot Phase I were conducted with the understanding that the efforts are expected to result in a commercial product to capture and disseminate the efficiency and environmental benefits of this new technology. An extensive state-of-art review was conducted to leverage the existing body of knowledge of micropilot ignition with respect to retrofit applications. Additionally, commercially-available fuel injection products were identified and applied to the program where appropriate. This approach will minimize the overall time-to-market requirements, while meeting performance and cost criteria. The four-cylinder prototype data was encouraging for the micro-pilot ignition technology when compared to spark ignition. Initial testing results showed: (1) Brake specific fuel consumption of natural gas was improved from standard spark ignition across the map, 1% at full load and 5% at 70% load. (2) 0% misfires for all points on micropilot ignition. Fuel savings were most likely due to this percent misfire improvement. (3

  6. Natural Gas Engine Performance Ignited by a Passively Q-Switched Microlaser

    SciTech Connect

    Bihari, Bipin; Biruduganti, Munidhar; Gupta, Sreenath

    2015-04-01

    A robust end pumped, passively Q-switched, air-cooled, microlaser was designed and prototyped to yield a 1064 nm pulsed laser output of 21 mJ/P with a pulse width of 4.2 ns FWHM. This microlaser was coupled to a standard laser plug carrying a sapphire lens with 13 mm back focal length. This assembly was tested in a natural gas fueled single-cylinder engine, and in one cylinder of a turbocharged 6-cylinder engine. Single cylinder engine tests showed extension of the lean ignition limit which enabled an efficiency improvement of 0.2% while meeting emission regulations. The tests conducted in the 6-cylinder engine showed highly improved ignition stability.

  7. Interim report on the assessment of engineering issues for compact high-field ignition devices

    SciTech Connect

    Flanagan, C.A.

    1986-04-01

    The engineering issues addressed at the workshop included the overall configuration, layout, and assembly; limiter and first-wall energy removal; magnet system structure design; fabricability; repairability; and costs. In performing the assessment, the primary features and characteristics of each concept under study were reviewed as representative of this class of ignition device. The emphasis was to understand the key engineering areas of concern for this class of device and deliberately not attempt to define an optimum design or to choose a best approach. The assessment concluded that compact ignition tokamaks, as represented by the three concepts under study, are feasible. A number of critical engineering issues were identified, and all appear to have tractable solutions. The engineering issues appear quite challenging, and to obtain increased confidence in the apparent design solutions requires completion of the next level of design detail, complemented by appropriate development programs and testing.

  8. Comparison of Waste Heat Recovery from the Exhaust of a Spark Ignition and a Diesel Engine

    NASA Astrophysics Data System (ADS)

    Wojciechowski, K. T.; Schmidt, M.; Zybala, R.; Merkisz, J.; Fuć, P.; Lijewski, P.

    2010-09-01

    We present herein a design for and performance measurements of a prototype thermoelectric generator (TEG) mounted on both a spark ignition engine (0.9 dm3) and a self-ignition engine (1.3 dm3). Using the prototype TEG as a tool, benchmark studies were performed in order to compare its parameters in terms of heat recovery from exhaust gases of both engine types. The test bed study was performed with an Automex AMX-210/100 eddy-current brake dynamometer. To provide a comprehensive overview of the TEG operating conditions, characterization of its parameters such as temperature distribution, heat flux density, and efficiency was done at engine speeds and loads similar to those within the range of operation of real road conditions.

  9. Some aspects of the CI engine modification aimed at operation on LPG with the application of spark ignition

    NASA Astrophysics Data System (ADS)

    Kaparuk, J.; Luft, S.; Skrzek, T.; Wojtyniak, M.

    2016-09-01

    A lot of investigation on modification of the compression ignition engine aimed at operation on LPG with the application of spark ignition has been carried out in the Laboratory of Vehicles and Combustion Engines at Kazimierz Pulaski University of Technology and Humanities in Radom. This paper presents results of investigation on establishment of the proper ignition advance angle in the modified engine. Within the framework of this investigation it was assessed the effect of this regulation on basic engine operating parameters, exhaust emission as well as basic combustion parameters.

  10. Biodiesel from plant seed oils as an alternate fuel for compression ignition engines-a review.

    PubMed

    Vijayakumar, C; Ramesh, M; Murugesan, A; Panneerselvam, N; Subramaniam, D; Bharathiraja, M

    2016-12-01

    The modern scenario reveals that the world is facing energy crisis due to the dwindling sources of fossil fuels. Environment protection agencies are more concerned about the atmospheric pollution due to the burning of fossil fuels. Alternative fuel research is getting augmented because of the above reasons. Plant seed oils (vegetable oils) are cleaner, sustainable, and renewable. So, it can be the most suitable alternative fuel for compression ignition (CI) engines. This paper reviews the availability of different types of plant seed oils, several methods for production of biodiesel from vegetable oils, and its properties. The different types of oils considered in this review are cashew nut shell liquid (CNSL) oil, ginger oil, eucalyptus oil, rice bran oil, Calophyllum inophyllum, hazelnut oil, sesame oil, clove stem oil, sardine oil, honge oil, polanga oil, mahua oil, rubber seed oil, cotton seed oil, neem oil, jatropha oil, egunsi melon oil, shea butter, linseed oil, Mohr oil, sea lemon oil, pumpkin oil, tobacco seed oil, jojoba oil, and mustard oil. Several methods for production of biodiesel are transesterification, pre-treatment, pyrolysis, and water emulsion are discussed. The various fuel properties considered for review such as specific gravity, viscosity, calorific value, flash point, and fire point are presented. The review also portrays advantages, limitations, performance, and emission characteristics of engine using plant seed oil biodiesel are discussed. Finally, the modeling and optimization of engine for various biofuels with different input and output parameters using artificial neural network, response surface methodology, and Taguchi are included.

  11. Experimental studies on the group ignition of a cloud of coal particles: Volume 2, Pyrolysis and ignition modeling

    SciTech Connect

    Annamalai, K.; Ryan, W.

    1992-01-01

    The primary objectives of this work are to formulate a model to simulate transient coal pyrolysis, ignition, and combustion of a cloud of coal particles and to compare results of the program with those reported in the literature elsewhere.

  12. Schlieren-based temperature measurement inside the cylinder of an optical spark ignition and homogeneous charge compression ignition engine.

    PubMed

    Aleiferis, Pavlos; Charalambides, Alexandros; Hardalupas, Yannis; Soulopoulos, Nikolaos; Taylor, A M K P; Urata, Yunichi

    2015-05-10

    Schlieren [Schlieren and Shadowgraphy Techniques (McGraw-Hill, 2001); Optics of Flames (Butterworths, 1963)] is a non-intrusive technique that can be used to detect density variations in a medium, and thus, under constant pressure and mixture concentration conditions, measure whole-field temperature distributions. The objective of the current work was to design a schlieren system to measure line-of-sight (LOS)-averaged temperature distribution with the final aim to determine the temperature distribution inside the cylinder of internal combustion (IC) engines. In a preliminary step, we assess theoretically the errors arising from the data reduction used to determine temperature from a schlieren measurement and find that the total error, random and systematic, is less than 3% for typical conditions encountered in the present experiments. A Z-type, curved-mirror schlieren system was used to measure the temperature distribution from a hot air jet in an open air environment in order to evaluate the method. Using the Abel transform, the radial distribution of the temperature was reconstructed from the LOS measurements. There was good agreement in the peak temperature between the reconstructed schlieren and thermocouple measurements. Experiments were then conducted in a four-stroke, single-cylinder, optical spark ignition engine with a four-valve, pentroof-type cylinder head to measure the temperature distribution of the reaction zone of an iso-octane-air mixture. The engine optical windows were designed to produce parallel rays and allow accurate application of the technique. The feasibility of the method to measure temperature distributions in IC engines was evaluated with simulations of the deflection angle combined with equilibrium chemistry calculations that estimated the temperature of the reaction zone at the position of maximum ray deflection as recorded in a schlieren image. Further simulations showed that the effects of exhaust gas recirculation and air

  13. Modeling spatio-temporal wildfire ignition point patterns

    Treesearch

    Amanda S. Hering; Cynthia L. Bell; Marc G. Genton

    2009-01-01

    We analyze and model the structure of spatio-temporal wildfire ignitions in the St. Johns River Water Management District in northeastern Florida. Previous studies, based on the K-function and an assumption of homogeneity, have shown that wildfire events occur in clusters. We revisit this analysis based on an inhomogeneous K-...

  14. Progress towards a lightning ignition model for the Northern Rockies

    Treesearch

    Paul Sopko; Don Latham

    2010-01-01

    We are in the process of constructing a lightning ignition model specific to the Northern Rockies using fire occurrence, lightning strike, ecoregion, and historical weather, NFDRS (National Fire Danger Rating System), lightning efficiency and lightning "possibility" data. Daily grids for each of these categories were reconstructed for the 2003 fire season (...

  15. Some Effects of Injection Advance Angle, Engine-Jacket Temperature, and Speed on Combustion in a Compression-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Waldron, C D

    1936-01-01

    An optical indicator and a high-speed motion-picture camera capable of operating at the rate of 2,000 frames per second were used to record simultaneously the pressure development and the flame formation in the combustion chamber of the NACA combustion apparatus. Tests were made at engine speeds of 570 and 1,500 r.p.m. The engine-jacket temperature was varied from 100 degrees to 300 degrees F. And the injection advance angle from 13 degrees after top center to 120 degrees before top center. The results show that the course of the combustion is largely controlled by the temperature and pressure of the air in the chamber from the time the fuel is injected until the time at which combustion starts and by the ignition lag. The conclusion is presented that in a compression-ignition engine with a quiescent combustion chamber the ignition lag should be the longest that can be used without excessive rates of pressure rise; any further shortening of the ignition lag decreased the effective combustion of the engine.

  16. Combustion process in a spark ignition engine: dynamics and noise level estimation.

    PubMed

    Kaminski, T; Wendeker, M; Urbanowicz, K; Litak, G

    2004-06-01

    We analyze the experimental time series of internal pressure in a four cylinder spark ignition engine. In our experiment, performed for different spark advance angles, apart from the usual cyclic changes of engine pressure we observed additional oscillations. These oscillations are with longer time scales ranging from one to several hundred engine cycles depending on engine working conditions. Based on the pressure time dependence we have calculated the heat released per combustion cycle. Using the time series of heat release to calculate the correlation coarse-grained entropy we estimated the noise level for internal combustion process. Our results show that for a larger spark advance angle the system is more deterministic.

  17. Fusion Ignition Rocket Engine with Ballistic Ablative Lithium Liner

    NASA Technical Reports Server (NTRS)

    Martin, Adam; Eskridge, Richard; Fimognari, Peter J., III.

    2005-01-01

    Thermo-nuclear fusion may be the key to a high Isp, high specific power (low alpha) propulsion system. In a fusion system energy is liberated within, and imparted directly to, the propellant. In principle, this can overcome the performance limitations inherent in systems that require thermal power transfer across a material boundary, and/or multiple power conversion stages (NTR, NEP). A thermo-nuclear propulsion system, which attempts to overcome some of the problems inherent in the ORION concept, is described. A passive tapered liner is launched behind a vehicle, through a hole in a pusher-plate, that is connected to the vehicle by a shock-absorbing mechanism. A dense FRC plasmoid is then accelerated to high velocity (in excess of 1,000 km/s) and shot through the hole into the liner, when it has reached a given point down-range. The kinetic energy of the FRC is converted into thermal and magnetic-field energy, igniting a fusion bum in the magnetically confined plasma. The fusion reaction serves as an ignition source for the liner, which is made out of detonable materials. The energy liberated in this process is converted to thrust by the pusher-plate, as in the classic ORION concept. However with this concept, the vehicle does not carry a magazine of pre-fabricated pulse-units. A magnetic nozzle may also be used, in place of the pusher-plate. Estimates of the conditions needed to achieve a sufficient gain will be presented, along with a description of the driver characteristics. The incorporation of this concept into the propulsion system of a spacecraft will also be discussed.

  18. Fusion Ignition Rocket Engine with Ballistic Ablative Lithium Liner

    NASA Technical Reports Server (NTRS)

    Martin, Adam; Eskridge, Richard; Fimognari, Peter J., III.

    2005-01-01

    Thermo-nuclear fusion may be the key to a high Isp, high specific power (low alpha) propulsion system. In a fusion system energy is liberated within, and imparted directly to, the propellant. In principle, this can overcome the performance limitations inherent in systems that require thermal power transfer across a material boundary, and/or multiple power conversion stages (NTR, NEP). A thermo-nuclear propulsion system, which attempts to overcome some of the problems inherent in the ORION concept, is described. A passive tapered liner is launched behind a vehicle, through a hole in a pusher-plate, that is connected to the vehicle by a shock-absorbing mechanism. A dense FRC plasmoid is then accelerated to high velocity (in excess of 1,000 km/s) and shot through the hole into the liner, when it has reached a given point down-range. The kinetic energy of the FRC is converted into thermal and magnetic-field energy, igniting a fusion bum in the magnetically confined plasma. The fusion reaction serves as an ignition source for the liner, which is made out of detonable materials. The energy liberated in this process is converted to thrust by the pusher-plate, as in the classic ORION concept. However with this concept, the vehicle does not carry a magazine of pre-fabricated pulse-units. A magnetic nozzle may also be used, in place of the pusher-plate. Estimates of the conditions needed to achieve a sufficient gain will be presented, along with a description of the driver characteristics. The incorporation of this concept into the propulsion system of a spacecraft will also be discussed.

  19. Engine performance and emission of compression ignition engine fuelled with emulsified biodiesel-water

    NASA Astrophysics Data System (ADS)

    Maawa, W. N.; Mamat, R.; Najafi, G.; Majeed Ali, O.; Aziz, A.

    2015-12-01

    The depletion of fossil fuel and environmental pollution has become world crucial issues in current era. Biodiesel-water emulsion is one of many possible approaches to reduce emissions. In this study, emulsified biodiesel with 4%, 6% and 8% of water contents were prepared to be used as fuel in a direct injection compression ignition engine. The performance indicator such as brake power, brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) and emissions such as NOx and particulate matter (PM) were investigated. The engine was set at constant speed of 2500 rpm and load from 20% to 60%. All the results were compared to B5 (blend of 95% petroleum diesel and 5% palm oil biodiesel) biodiesel. At low load, the BSFC decrease by 12.75% at 4% water ratio and decreased by 1.5% at 6% water ratio. However, the BSFC increases by 17.19% with increasing water ratio to 8% compared to B5. Furthermore, there was no significant decrease in brake power and BTE at 60% load. For 20% and 40% load there was some variance regarding to brake power and BTE. Significant reduction in NOx and PM emissions by 73.87% and 20.00% respectively were achieved with increasing water ratio to 8%. Overall, it is observed that the emulsified of biodiesel-water is an appropriate alternative fuel method to reduce emissions.

  20. Volatility characterization of nanoparticles from single and dual-fuel low temperature combustion in compression ignition engines

    DOE PAGES

    Lucachick, Glenn; Curran, Scott; Storey, John Morse; ...

    2016-03-10

    Our work explores the volatility of particles produced from two diesel low temperature combustion (LTC) modes proposed for high-efficiency compression ignition engines. It also explores mechanisms of particulate formation and growth upon dilution in the near-tailpipe environment. Moreover, the number distribution of exhaust particles from low- and mid-load dual-fuel reactivity controlled compression ignition (RCCI) and single-fuel premixed charge compression ignition (PPCI) modes were experimentally studied over a gradient of dilution temperature. Particle volatility of select particle diameters was investigated using volatility tandem differential mobility analysis (V-TDMA). Evaporation rates for exhaust particles were compared with V-TDMA results for candidate pure n-alkanesmore » to identify species with similar volatility characteristics. The results show that LTC particles are mostly comprised of material with volatility similar to engine oil alkanes. V-TDMA results were used as inputs to an aerosol condensation and evaporation model to support the finding that smaller particles in the distribution are comprised of lower volatility material than large particles under primary dilution conditions. Although the results show that saturation levels are high enough to drive condensation of alkanes onto existing particles under the dilution conditions investigated, they are not high We conclude that observed particles from LTC operation must grow from low concentrations of highly non-volatile compounds present in the exhaust.« less

  1. Volatility characterization of nanoparticles from single and dual-fuel low temperature combustion in compression ignition engines

    SciTech Connect

    Lucachick, Glenn; Curran, Scott; Storey, John Morse; Prikhodko, Vitaly Y.; Northrop, William F.

    2016-03-10

    Our work explores the volatility of particles produced from two diesel low temperature combustion (LTC) modes proposed for high-efficiency compression ignition engines. It also explores mechanisms of particulate formation and growth upon dilution in the near-tailpipe environment. Moreover, the number distribution of exhaust particles from low- and mid-load dual-fuel reactivity controlled compression ignition (RCCI) and single-fuel premixed charge compression ignition (PPCI) modes were experimentally studied over a gradient of dilution temperature. Particle volatility of select particle diameters was investigated using volatility tandem differential mobility analysis (V-TDMA). Evaporation rates for exhaust particles were compared with V-TDMA results for candidate pure n-alkanes to identify species with similar volatility characteristics. The results show that LTC particles are mostly comprised of material with volatility similar to engine oil alkanes. V-TDMA results were used as inputs to an aerosol condensation and evaporation model to support the finding that smaller particles in the distribution are comprised of lower volatility material than large particles under primary dilution conditions. Although the results show that saturation levels are high enough to drive condensation of alkanes onto existing particles under the dilution conditions investigated, they are not high We conclude that observed particles from LTC operation must grow from low concentrations of highly non-volatile compounds present in the exhaust.

  2. Experimental investigation on laser-induced plasma ignition of hydrocarbon fuel in scramjet engine at takeover flight conditions

    NASA Astrophysics Data System (ADS)

    Li, Xipeng; Liu, Weidong; Pan, Yu; Yang, Leichao; An, Bin

    2017-09-01

    Laser-induced plasma ignition of an ethylene fuelled cavity is successfully conducted in a model scramjet engine combustor with dual cavities. The simulated flight condition corresponds to takeover flight Mach 4, with isolator entrance Mach number of 2.1, the total pressure of 0.65 MPa and stagnation temperature of 947 K. Ethylene is injected 35 mm upstream of cavity flameholder from four orifices with 2-mm-diameter. The 1064 nm laser beam, from a Q-switched Nd:YAG laser source running at 10 Hz and 940 mJ per pulse, is focused into cavity for ignition. High speed photography is used to capture the transient ignition process. The laser-induced gas breakdown, flame kernel generation and propagation are all recorded and ensuing stable supersonic combustion is established in cavity. The highly ionized plasma zone is almost round at starting, and then the surface of the flame kernel is wrinkled severely in 150 μs after the laser pulse due to the strong turbulence flow in cavity. The flame kernel is found rotating anti-clockwise and gradually moves upstream as the entrainment of circulation flow in cavity. The flame is stabilized at the corner of the cavity for about 200 μs, and then spreads from leading edge to trailing edge via the under part of shear layer to fully fill the entire cavity. The corner recirculation zone of cavity is of great importance for flame spreading. Eventually, a cavity shear-layer stabilized combustion is established in the supersonic flow roughly 2.9 ms after the laser pulse. Both the temporal evolution of normalized chemiluminescence intensity and normalized flame area show that the entire ignition process can be divided into four stages, which are referred as turbulent dissipation stage, combustion enhancement stage, reverting stage and combustion stabilization stage. The results show promising potentials of laser induced plasma for ignition in real scramjets.

  3. Low Noise Catalytic Ignition I.C. Engine.

    DTIC Science & Technology

    1987-01-01

    prototype was built using Inconel fasteners. These have proven durable at the engine’s operating temperatures. However, fastener clearance problems in the... CFR engine in which the piston crown had been coated with platinum. The durability of this coating was low but it was reported that the presence of

  4. IMPROVEMENT TO PIPELINE COMPRESSOR ENGINE RELIABILITY THROUGH RETROFIT MICRO-PILOT IGNITION SYSTEM

    SciTech Connect

    Ted Bestor

    2004-06-01

    This report documents the second year's effort towards a 3-year program to develop micropilot ignition systems for existing pipeline compressor engines. In essence, all Phase II goals and objectives were met. We intend to proceed with the Phase III research plan, as set forth by the applicable Research Management Plan. The objective for Phase II was to further develop and optimize the micropilot ignition system for large bore, slow speed engines operating at low compression ratios. The primary elements of Micropilot Phase II were to evaluate the results for the 4-cylinder system prototype developed for Phase I, then optimize this system to demonstrate the technology's readiness for the field demonstration phase. In all, there were twelve (12) tasks defined and executed to support objectives in a stepwise fashion. Task-specific approaches and results are documented in this report. Research activities for Micropilot Phase II were conducted with the understanding that the efforts are expected to result in a commercial product to capture and disseminate the efficiency and environmental benefits of this new technology. Commercially-available fuel injection products were identified and applied to the program where appropriate. Modifications to existing engine components were kept to a minimum. This approach will minimize the overall time-to-market requirements, while meeting performance and cost criteria. The optimized four-cylinder system data demonstrated significant progress compared to Phase I results, as well as traditional spark ignition systems. An extensive testing program at the EECL using the GMV-4 test engine demonstrated that: (1) In general, the engine operated more stable fewer misfires and partial combustion events when using the 3-hole injectors compared to the 5-hole injectors used in Phase I. (2) The engine had, in general, a wider range of operation with the 3-hole injectors. Minimum operational boost levels were approximately 5''Hg lower and the

  5. Effects of Ignition and Injection Perturbation under Lean and Dilute GDI Engine Operation

    SciTech Connect

    Wallner, Thomas; Kaul, Brian C; Sevik, James; Scarcelli, Riccardo; Wagner, Robert M

    2015-01-01

    Turbocharged gasoline direct injection (GDI) engines are quickly becoming more prominent in light-duty automotive applications because of their potential improvements in efficiency and fuel economy. While EGR dilute and lean operation serve as potential pathways to further improve efficiencies and emissions in GDI engines, they also pose challenges for stable engine operation. Tests were performed on a single-cylinder research engine that is representative of current automotive-style GDI engines. Baseline cases were performed under steady-state operating conditions where combustion phasing and dilution levels were varied to determine the effects on indicated efficiency and combustion stability. Sensitivity studies were then carried out by introducing binary low-high perturbation of spark timing and injection duration on a cycle-by-cycle basis under EGR dilute and lean operation to determine dominant feedback mechanisms. Ignition perturbation was phased early/late of MBT timing, and injection perturbation was set fuel rich/lean of the given air-to-fuel ratio. COVIMEP was used to define acceptable operation limits when comparing different perturbation cases. Overall sensitivity data shows COVIMEP is more sensitive to injection perturbation over ignition perturbation. This is because of the greater effect injection perturbation has on combustion phasing, ignition delay, and combustion duration.

  6. Experimental Investigation of Augmented Spark Ignition of a LO2/LCH4 Reaction Control Engine at Altitude Conditions

    NASA Technical Reports Server (NTRS)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of nontoxic propellants in future exploration vehicles would enable safer, more cost-effective mission scenarios. One promising green alternative to existing hypergols is liquid methane (LCH4) with liquid oxygen (LO2). A 100 lbf LO2/LCH4 engine was developed under the NASA Propulsion and Cryogenic Advanced Development project and tested at the NASA Glenn Research Center Altitude Combustion Stand in a low pressure environment. High ignition energy is a perceived drawback of this propellant combination; so this ignition margin test program examined ignition performance versus delivered spark energy. Sensitivity of ignition to spark timing and repetition rate was also explored. Three different exciter units were used with the engine s augmented (torch) igniter. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks. This suggests that rising pressure and flow rate increase spark impedance and may at some point compromise an exciter s ability to complete each spark. The reduced spark energies of such quenched deliveries resulted in more erratic ignitions, decreasing ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1 to 6 mJ, though multiple, similarly timed sparks of 55 to 75 mJ were required for reliable ignition. Delayed spark application and reduced spark repetition rate both correlated with late and occasional failed ignitions. An optimum time interval for spark application and ignition therefore coincides with propellant introduction to the igniter.

  7. Effects of Fuel Composition on EGR Dilution Tolerance in Spark Ignited Engines

    SciTech Connect

    Szybist, James P

    2016-01-01

    Fuel-specific differences in exhaust gas recirculation (EGR) dilution tolerance are studied in a modern, direct-injection single-cylinder research engine. A total of 6 model fuel blends are examined at a constant research octane number (RON) of 95 using n-heptane, iso-octane, toluene, and ethanol. Laminar flame speeds for these mixtures, which were calculated two different methods (an energy fraction mixing rule and a detailed kinetic simulation), spanned a range of about 6 cm/s. A constant fueling nominal load of 350 kPa IMEPg at 2000 rpm was operated with varying CA50 from 8-20 CAD aTDCf, and with EGR increasing until a COV of IMEP of 5% is reached. The results illustrate that flame speed affects EGR dilution tolerance; fuels with increased flame speeds increase EGR tolerance. Specifically, flame speed correlates most closely to the initial flame kernel growth, measured as the time of ignition to 5% mass fraction burned. The effect of the latent heat of vaporization on the flame speed is taken into account for the ethanol-containing fuels. At a 30 vol% blend level, the increased enthalpy of vaporization of ethanol compared to conventional hydrocarbons can decrease the temperature at the time of ignition by a maximum of 15 C, which can account for up to a 3.5 cm/s decrease in flame speed. The ethanol-containing fuels, however, still exhibit a flame speed advantage, and a dilution tolerance advantage over the slower flame-speed fuels. The fuel-specific differences in dilution tolerance are significant at the condition examined, allowing for a 50% relative increase in EGR (4% absolute difference in EGR) at a constant COV of IMEP of 3%.

  8. IMPROVEMENT TO PIPELINE COMPRESSOR ENGINE RELIABILITY THROUGH RETROFIT MICRO-PILOT IGNITION SYSTEM -- PHASE III

    SciTech Connect

    Scott Chase; Daniel Olsen; Ted Bestor

    2005-03-01

    This report documents the third year's effort towards a 3-year program conducted by the Engines & Energy Conversion Laboratory (EECL) at Colorado State University (CSU) to develop micropilot ignition systems for existing pipeline compressor engines. Research activities for the overall program were conducted with the understanding that the efforts are to result in a commercial product to capture and disseminate the efficiency and environmental benefits of this new technology. Commercially-available fuel injection products were identified and applied to the program where appropriate. This approach will minimize the overall time-to-market requirements, while meeting performance and cost criteria. Two earlier phases of development precede this report. The objective for Phase I was to demonstrate the feasibility of retrofit micropilot ignition (RMI) systems for large bore, slow speed engines operating at low compression ratios under laboratory conditions at the EECL. The objective for Phase II was to further develop and optimize the micropilot ignition system at the EECL for large bore, slow speed engines operating at low compression ratios. These laboratory results were enhanced, then verified via a field demonstration project during Phase III of the Micropilot Ignition program. An Implementation Team of qualified engine retrofit service providers was assembled to install the retrofit micropilot ignition system for an engine operated by El Paso Pipeline Group at a compressor station near Window Rock, Arizona. Testing of this demonstration unit showed that the same benefits identified by laboratory testing at CSU, i.e., reduced fuel consumption and exhaust emissions (NOx, THC, CO, and CH2O). Installation efforts at Window Rock were completed towards the end of the budget period, which did not leave sufficient time to complete the durability testing. These efforts are ongoing, with funding provided by El Paso Pipeline Group, and the results will be documented in a report

  9. Analysis of biomass and waste gasification lean syngases combustion for power generation using spark ignition engines.

    PubMed

    Marculescu, Cosmin; Cenuşă, Victor; Alexe, Florin

    2016-01-01

    The paper presents a study for food processing industry waste to energy conversion using gasification and internal combustion engine for power generation. The biomass we used consisted in bones and meat residues sampled directly from the industrial line, characterised by high water content, about 42% in mass, and potential health risks. Using the feedstock properties, experimentally determined, two air-gasification process configurations were assessed and numerically modelled to quantify the effects on produced syngas properties. The study also focused on drying stage integration within the conversion chain: either external or integrated into the gasifier. To comply with environmental regulations on feedstock to syngas conversion both solutions were developed in a closed system using a modified down-draft gasifier that integrates the pyrolysis, gasification and partial oxidation stages. Good quality syngas with up to 19.1% - CO; 17% - H2; and 1.6% - CH4 can be produced. The syngas lower heating value may vary from 4.0 MJ/Nm(3) to 6.7 MJ/Nm(3) depending on process configuration. The influence of syngas fuel properties on spark ignition engines performances was studied in comparison to the natural gas (methane) and digestion biogas. In order to keep H2 molar quota below the detonation value of ⩽4% for the engines using syngas, characterised by higher hydrogen fraction, the air excess ratio in the combustion process must be increased to [2.2-2.8]. The results in this paper represent valuable data required by the design of waste to energy conversion chains with intermediate gas fuel production. The data is suitable for Otto engines characterised by power output below 1 MW, designed for natural gas consumption and fuelled with low calorific value gas fuels.

  10. Space Shuttle Main Engine fuel preburner augmented spark igniter shutdown detonations

    NASA Technical Reports Server (NTRS)

    Dexter, C. E.; Mccay, T. D.

    1986-01-01

    Detonations were experienced in the Space Shuttle Main Engine fuel preburner (FPB) augmented spark igniter (ASI) during engine cutoff. Several of these resulted in over pressures sufficient to damage the FPB ASI oxidizer system. The detonations initiated in the FPB ASI oxidizer line when residual oxidizer (oxygen) in the line mixed with backflowing fuel (hydrogen) and detonated. This paper reviews the damage history to the FPB ASI oxidizer system, an engineering assessment of the problem cause, a verification of the mechanisms, the hazards associated with the detonations, and the solution implemented.

  11. Compression ignition engine fuel properties of a used sunflower oil-diesel fuel blend

    SciTech Connect

    Oezaktas, T.

    2000-05-01

    Vegetable oils may be used with dilution modification technique as an alternative diesel fuel. In this study, a used sunflower oil-diesel fuel blend (20:80 {nu}/{nu}%) was investigated in a Pancar Motor E-108-type diesel engine to observe engine characteristics and exhaust emission. The effect of the compression ratio on ignition delay characteristics and smoke emissions of blend fuel was determined in this CFR engine. The results of fuel blends were compared with the reference grade No. 2-D diesel fuel.

  12. Challenging and Future of Homogeneous Charge Compression Ignition Engines; an Advanced and Novel Concepts Review

    NASA Astrophysics Data System (ADS)

    Elkelawy, Medhat; Yu-Sheng, Zhang; Hagar, Alm El-Din; Yu, Jing-Zhou

    The potential of HCCI combustion to reduce the internal combustion engines exhaust emissions, particularly NOX and soot emissions, and to delimit the application range of this technique as well as a detailed analysis of previous and current results of combustion chemistry, emission behaviors, the challenging facing this technique, and all controlling parameters including transient states are introduced. From HCCI combustion chemistry and emissions analysis it was found that, the heavy fuels displays two-stage heat release or two stage combustion process involving low temperature oxidation (LTO) stage followed by high temperature oxidation (HTO) stage separated by a time delay between them is attributed to negative temperature coefficient (NTC), the advantage of NOX emissions reduction from HCCI engine diminishing at high load condition, HC production is reduced with increasing the engine load, and the soot ejection is negligible during all operating conditions. Valve timing, compression ratio, inlet air temperature, and EGR show an advanced control on the HCCI combustion behaviors over a wide range of speed and load. The use of EGR in HCCI operation is limited at EGR-rates about 70% at this point the reaction rates and ignition timing are so much reduced and retarded, respectively, and leads to misfiring and production of HC-emissions. Homogenization of fuel, air, and recycled burnt gases prior to ignition in addition to the control of ignition and combustion timing, and heat release rates are obstructs that must be overcome in order to realize the advantages of HCCI engine in the future.

  13. Microexplosions and ignition dynamics in engineered aluminum/polymer fuel particles

    DOE PAGES

    Rubio, Mario A.; Gunduz, I. Emre; Groven, Lori J.; ...

    2016-11-11

    Aluminum particles are widely used as a metal fuel in solid propellants. However, poor combustion efficiencies and two-phase flow losses result due in part to particle agglomeration. Engineered composite particles of aluminum (Al) with inclusions of polytetrafluoroethylene (PTFE) or low-density polyethylene (LDPE) have been shown to improve ignition and yield smaller agglomerates in solid propellants, recently. Reductions in agglomeration were attributed to internal pressurization and fragmentation (microexplosions) of the composite particles at the propellant surface. We explore the mechanisms responsible for microexplosions in order to better understand the combustion characteristics of composite fuel particles. Single composite particles of Al/PTFE andmore » Al/LDPE with diameters between 100 and 1200 µm are ignited on a substrate to mimic a burning propellant surface in a controlled environment using a CO2 laser in the irradiance range of 78–7700 W/cm2. Furthermore, the effects of particle size, milling time, and inclusion content on the resulting ignition delay, product particle size distributions, and microexplosion tendencies are reported. For example particles with higher PTFE content (30 wt%) had laser flux ignition thresholds as low as 77 W/cm2, exhibiting more burning particle dispersion due to microexplosions compared to the other materials considered. Composite Al/LDPE particles exhibit relatively high ignition thresholds compared to Al/PTFE particles, and microexplosions were observed only with laser fluxes above 5500 W/cm2 due to low LDPE reactivity with Al resulting in negligible particle self-heating. However, results show that microexplosions can occur for Al containing both low and high reactivity inclusions (LDPE and PTFE, respectively) and that polymer inclusions can be used to tailor the ignition threshold. Furthermore, this class of modified metal particles shows significant promise for application in many different energetic materials

  14. Microexplosions and ignition dynamics in engineered aluminum/polymer fuel particles

    SciTech Connect

    Rubio, Mario A.; Gunduz, I. Emre; Groven, Lori J.; Sippel, Travis R.; Han, Chang Wan; Unocic, Raymond R.; Ortalan, Volkan; Son, Steven F.

    2016-11-11

    Aluminum particles are widely used as a metal fuel in solid propellants. However, poor combustion efficiencies and two-phase flow losses result due in part to particle agglomeration. Engineered composite particles of aluminum (Al) with inclusions of polytetrafluoroethylene (PTFE) or low-density polyethylene (LDPE) have been shown to improve ignition and yield smaller agglomerates in solid propellants, recently. Reductions in agglomeration were attributed to internal pressurization and fragmentation (microexplosions) of the composite particles at the propellant surface. We explore the mechanisms responsible for microexplosions in order to better understand the combustion characteristics of composite fuel particles. Single composite particles of Al/PTFE and Al/LDPE with diameters between 100 and 1200 µm are ignited on a substrate to mimic a burning propellant surface in a controlled environment using a CO2 laser in the irradiance range of 78–7700 W/cm2. Furthermore, the effects of particle size, milling time, and inclusion content on the resulting ignition delay, product particle size distributions, and microexplosion tendencies are reported. For example particles with higher PTFE content (30 wt%) had laser flux ignition thresholds as low as 77 W/cm2, exhibiting more burning particle dispersion due to microexplosions compared to the other materials considered. Composite Al/LDPE particles exhibit relatively high ignition thresholds compared to Al/PTFE particles, and microexplosions were observed only with laser fluxes above 5500 W/cm2 due to low LDPE reactivity with Al resulting in negligible particle self-heating. However, results show that microexplosions can occur for Al containing both low and high reactivity inclusions (LDPE and PTFE, respectively) and that polymer inclusions can be used to tailor the ignition threshold. Furthermore, this class of modified metal particles shows significant promise for application in

  15. DESIGN OF A HIGH COMPRESSION, DIRECT INJECTION, SPARK-IGNITION, METHANOL FUELED RESEARCH ENGINE WITH AN INTEGRAL INJECTOR-IGNITION SOURCE INSERT, SAE PAPER 2001-01-3651

    EPA Science Inventory

    A stratified charge research engine and test stand were designed and built for this work. The primary goal of this project was to evaluate the feasibility of using a removal integral injector ignition source insert which allows a convenient method of charging the relative locat...

  16. DESIGN OF A HIGH COMPRESSION, DIRECT INJECTION, SPARK-IGNITION, METHANOL FUELED RESEARCH ENGINE WITH AN INTEGRAL INJECTOR-IGNITION SOURCE INSERT, SAE PAPER 2001-01-3651

    EPA Science Inventory

    A stratified charge research engine and test stand were designed and built for this work. The primary goal of this project was to evaluate the feasibility of using a removal integral injector ignition source insert which allows a convenient method of charging the relative locat...

  17. A Photographic Study of Combustion and Knock in a Spark-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Spencer, R C

    1938-01-01

    Report presents the results of a photographic study of the combustion in a spark-ignition engine using both Schlieren and flame photographs taken at high rates of speed. Although shock waves are present after knock occurs, there was no evidence of any type of sonic or supersonic compression waves existing in the combustion gases prior to the occurrence of knock. Artificially induced shock waves in the engine did not in themselves cause knock. The photographs also indicate that, although auto-ignition ahead of the flame front may occur in conjunction with knock, it is not necessary for the occurrence of knock. There is also evidence that the reaction is not completed in the flame front but continues for some time after the flame front has passed through the charge.

  18. Improvement of non-isobaric model for shock ignition

    NASA Astrophysics Data System (ADS)

    Farahbod, Amir Hossein; Abolfazl Ghasemi, Seyed; Jafar Jafari, Mohammad; Rezaei, Somayeh; Sobhanian, Samad

    2014-10-01

    In this paper, improved relations of total fuel energy, fuel gain, hot-spot radius and total areal density in a non-isobaric model of fuel assembly have been derived and compared with the numerical results of [J. Schmitt, J.W. Bates, S.P. Obenschain, S.T. Zalesak, D.E. Fyfe, Phys. Plasmas 17, 042701 (2010); S. Atzeni, A. Marocchino, A. Schiavi, G. Schurtz, New J. Phys. 15, 045004 (2013)] and several simulations performed by MULTI-1D radiation hydrodynamic code for shock ignition scenario. Our calculations indicate that the approximations made by [M.D. Rosen, J.D. Lindl, A.R. Thiessen, LLNL Laser Program Annual Report, UCRL-50021-83, pp. 3-5 (1983); J. Schmitt, J.W. Bates, S.P. Obenschain, S.T. Zalesak, D.E. Fyfe, Phys. Plasmas 17, 042701 (2010)] for the calculation of burn-up fraction are not accurate enough to give results consistent with simulations. Therefore, we have introduced more appropriate approximations for the burn-up fraction and total areal density of the fuel that are in more agreement with simulation results of shock ignition. Meanwhile, it is shown that the related formulas of the non-isobaric model for total fuel energy, fuel gain and also hot-spot radius cannot determine the model parameters independently, but improved model choose a better selection and less restrictions on determination of the parameters for the non-isobaric model. Such derivations can be used in theoretical studies of the ignition conditions and burn-up fraction of the fuel in shock ignition scenario.

  19. Experimental determination of the filling coefficient for an aspirated spark-ignition engine

    NASA Astrophysics Data System (ADS)

    Raţiu, S.; Alexa, V.; Kiss, I.; Cioată, V.

    2017-01-01

    This study aims at determining, by experiment, the filling coefficient of a spark-ignition, normal aspirated engine, with carburettor. For this purpose, a pilot plant was designed for measuring the pressure at various points on the route, simulating a stationary air flow regime by means of a vacuum pump. Measurements were made for various lifting heights of the intake valve and various opening positions of the throttle body, thus highlighting how their influence on the pressure loss and on the filling coefficient.

  20. CARBON DEFLAGRATION IN TYPE Ia SUPERNOVA. I. CENTRALLY IGNITED MODELS

    SciTech Connect

    Ma, H.; Woosley, S. E.; Malone, C. M.; Almgren, A.; Bell, J.

    2013-07-01

    A leading model for Type Ia supernovae (SNe Ia) begins with a white dwarf near the Chandrasekhar mass that ignites a degenerate thermonuclear runaway close to its center and explodes. In a series of papers, we shall explore the consequences of ignition at several locations within such dwarfs. Here we assume central ignition, which has been explored before, but is worth revisiting, if only to validate those previous studies and to further elucidate the relevant physics for future work. A perturbed sphere of hot iron ash with a radius of {approx}100 km is initialized at the middle of the star. The subsequent explosion is followed in several simulations using a thickened flame model in which the flame speed is either fixed-within the range expected from turbulent combustion-or based on the local turbulent intensity. Global results, including the explosion energy and bulk nucleosynthesis (e.g., {sup 56}Ni of 0.48-0.56 M{sub Sun }) turn out to be insensitive to this speed. In all completed runs, the energy released by the nuclear burning is adequate to unbind the star, but not enough to give the energy and brightness of typical SNe Ia. As found previously, the chemical stratification observed in typical events is not reproduced. These models produce a large amount of unburned carbon and oxygen in central low velocity regions, which is inconsistent with spectroscopic observations, and the intermediate mass elements and iron group elements are strongly mixed during the explosion.

  1. Infrared radiation from explosions in a spark-ignition engine

    NASA Technical Reports Server (NTRS)

    Marvin, Charles F , Jr; Caldwell, Frank R; Steele, Sydney

    1935-01-01

    This report presents the results of an investigation to determine the variations in intensity and spectral distribution of the radiant energy emitted by the flames during normal and knocking explosions in an engine. Radiation extending into the infrared was transmitted by a window of fluorite, placed either near the spark plug or over the detonation zone at opposite ends of the combustion chamber. Concave, surface-silvered mirrors focused the beam, first at the slit of a stroboscope which opened for about 2 degrees of crank angle at any desired point in the engine cycle, and then upon the target of a sensitive thermocouple for measuring radiation intensity. Spectral distribution of the radiant energy was determined by placing over the window, one at a time, a series of five filters selected with a view to identifying, as far as possible without the use of a spectrograph, the characteristic emissions of water vapor, carbon dioxide, and incandescent carbon.

  2. Orange oil and its application to spark ignition engine

    SciTech Connect

    Takeda, S.

    1982-12-01

    Orange oil can be extracted from the peel of citrus. In Japan the production of orange oil is about 2000 tons per year. No orange oil has been however used for any specific purpose. The main ingredient of orange oil consists of d-limonen. About 0.6-1.0% oil can be extracted from the peel of ''Unshu orange'', which is a kind of typical Japanese tangerine. Orange oil has 106-140 research octane number which is good for running the CFR engine. The flash point of orange oil measured by Pensky-Martens method was at 56/sup 0/C. For the use of orange oil only as fuel without blending, there was found to be some difficulty in engine startability under cold conditions.

  3. Highly resolved numerical simulation of combustion downstream of a rocket engine igniter

    NASA Astrophysics Data System (ADS)

    Buttay, R.; Gomet, L.; Lehnasch, G.; Mura, A.

    2017-07-01

    We study ignition processes in the turbulent reactive flow established downstream of highly under-expanded coflowing jets. The corresponding configuration is typical of a rocket engine igniter, and to the best knowledge of the authors, this study is the first that documents highly resolved numerical simulations of such a reactive flowfield. Considering the discharge of axisymmetric coaxial under-expanded jets, various morphologies are expected, depending on the value of the nozzle pressure ratio, a key parameter used to classify them. The present computations are conducted with a value of this ratio set to fifteen. The simulations are performed with the massively parallel CREAMS solver on a grid featuring approximately 440,000,000 computational nodes. In the main zone of interest, the level of spatial resolution is D/74, with D the central inlet stream diameter. The computational results reveal the complex topology of the compressible flowfield. The obtained results also bring new and useful insights into the development of ignition processes. In particular, ignition is found to take place rather far downstream of the shock barrel, a conclusion that contrasts with early computational studies conducted within the unsteady RANS computational framework. Consideration of detailed chemistry confirms the essential role of hydroperoxyl radicals, while the analysis of the Takeno index reveals the predominance of a non-premixed combustion mode.

  4. Highly resolved numerical simulation of combustion downstream of a rocket engine igniter

    NASA Astrophysics Data System (ADS)

    Buttay, R.; Gomet, L.; Lehnasch, G.; Mura, A.

    2017-02-01

    We study ignition processes in the turbulent reactive flow established downstream of highly under-expanded coflowing jets. The corresponding configuration is typical of a rocket engine igniter, and to the best knowledge of the authors, this study is the first that documents highly resolved numerical simulations of such a reactive flowfield. Considering the discharge of axisymmetric coaxial under-expanded jets, various morphologies are expected, depending on the value of the nozzle pressure ratio, a key parameter used to classify them. The present computations are conducted with a value of this ratio set to fifteen. The simulations are performed with the massively parallel CREAMS solver on a grid featuring approximately 440,000,000 computational nodes. In the main zone of interest, the level of spatial resolution is D/74, with D the central inlet stream diameter. The computational results reveal the complex topology of the compressible flowfield. The obtained results also bring new and useful insights into the development of ignition processes. In particular, ignition is found to take place rather far downstream of the shock barrel, a conclusion that contrasts with early computational studies conducted within the unsteady RANS computational framework. Consideration of detailed chemistry confirms the essential role of hydroperoxyl radicals, while the analysis of the Takeno index reveals the predominance of a non-premixed combustion mode.

  5. Comparative performance study of spark ignition engines burning alcohols, gasoline, and alcohol-gasoline blends

    SciTech Connect

    Desoky, A.A.; Rabie, L.H.

    1983-12-01

    In recent years it has been clear that the reserves of oil, from which petrol is refined, are becoming limited. In order to conserve these stocks of oil, and to minimize motoring costs as the price of dwindling oil resources escalates, it's obviously desirable to improve the thermal efficiency of the spark ignition engine. There are also obvious benefits to be obtained from making spark ignition engines run efficiently on alternative fuel, (non-crude based fuel). It has been claimed that hydrogen is an ideal fuel for the internal combustion engine it certainly causes little pollution, but is difficult to store, high in price, and difficult to burn efficiently in the engine without it knocking and backfiring. These problems arise because of the very wide flammability limits and the very high flame velocity of hydrogen. Alcohols used an additive or substitute for gasoline could immediately help to solve both energy and pollution problems. An experimental tests were carried out at Mansoura University Laboratories using a small single cylinder SIE, fully instrumented to measure the engine performance. The engine was fueled with pure methonol, pure ethonol, gasoline methanol blends and gasaline ethanol blends. The results showed that in principle, from kechnological aspects it's possible to use alcohols as a gasoline extender or as alcohol's gasoline, blends for automobiles. With regard to energy consumptions alcohols and alcohols gasoline blends lead to interesting results. The fuel economy benefits of using alcohols gasoline blends was found to be interesting in the part throltle operation.

  6. Nanostructured energetic composites: synthesis, ignition/combustion modeling, and applications.

    PubMed

    Zhou, Xiang; Torabi, Mohsen; Lu, Jian; Shen, Ruiqi; Zhang, Kaili

    2014-03-12

    Nanotechnology has stimulated revolutionary advances in many scientific and industrial fields, particularly in energetic materials. Powder mixing is the simplest and most traditional method to prepare nanoenergetic composites, and preliminary findings have shown that these composites perform more effectively than their micro- or macro-sized counterparts in terms of energy release, ignition, and combustion. Powder mixing technology represents only the minimum capability of nanotechnology to boost the development of energetic material research, and it has intrinsic limitations, namely, random distribution of fuel and oxidizer particles, inevitable fuel pre-oxidation, and non-intimate contact between reactants. As an alternative, nanostructured energetic composites can be prepared through a delicately designed process. These composites outperform powder-mixed nanocomposites in numerous ways; therefore, we comprehensively discuss the preparation strategies adopted for nanostructured energetic composites and the research achievements thus far in this review. The latest ignition and reaction models are briefly introduced. Finally, the broad promising applications of nanostructured energetic composites are highlighted.

  7. Pegasus Engine Ignites after Drop from B-52 Mothership

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Against the midnight blue of a high-altitude sky, Orbital Sciences' Pegasus winged rocket booster ignites after being dropped from NASA's B-52 mothership on a July 1991 flight. A NASA chase plane for the flight is also visible above the rocket and below the B-52. Pegasus is an air-launched space booster produced by Orbital Sciences Corporation and Hercules Aerospace Company (initially; later, Alliant Tech Systems) to provide small satellite users with a cost-effective, flexible, and reliable method for placing payloads into low earth orbit. Pegasus has been used to launch a number of satellites and the PHYSX experiment. That experiment consisted of a smooth glove installed on the first-stage delta wing of the Pegasus. The glove was used to gather data at speeds of up to Mach 8 and at altitudes approaching 200,000 feet. The flight took place on October 22, 1998. The PHYSX experiment focused on determining where boundary-layer transition occurs on the glove and on identifying the flow mechanism causing transition over the glove. Data from this flight-research effort included temperature, heat transfer, pressure measurements, airflow, and trajectory reconstruction. Hypersonic flight-research programs are an approach to validate design methods for hypersonic vehicles (those that fly more than five times the speed of sound, or Mach 5). Dryden Flight Research Center, Edwards, California, provided overall management of the glove experiment, glove design, and buildup. Dryden also was responsible for conducting the flight tests. Langley Research Center, Hampton, Virginia, was responsible for the design of the aerodynamic glove as well as development of sensor and instrumentation systems for the glove. Other participating NASA centers included Ames Research Center, Mountain View, California; Goddard Space Flight Center, Greenbelt, Maryland; and Kennedy Space Center, Florida. Orbital Sciences Corporation, Dulles, Virginia, is the manufacturer of the Pegasus vehicle, while

  8. Modelling ignition characteristics of rich H2/O2 mixture in a monolithic catalytic reactor

    NASA Technical Reports Server (NTRS)

    Tien, Ta-Ching; T'Ien, James S.

    1988-01-01

    Ignition of rich hydrogen-oxygen mixture in a monolithic catalytic reactor is studied using a transient combustion model. The model assumes a quasi-steady gas phase and a thermally-thin substrate. The ignition time lag is due to the thermal inertia of the substrate. One-step global chemical reaction is assumed both on the surface and in the gas phase. An effectiveness factor is introduced to account for the transition from a kinetically-limited catalytic surface reaction to a diffusion-limit one during ignition. Results presented include a catalytic ignition boundary, ignition delay time and the transient response in the catalytic bed.

  9. Improving the performance of a compression ignition engine by directing flow of inlet air

    NASA Technical Reports Server (NTRS)

    Kemper, Carlton

    1946-01-01

    The object of this report is to present the results of tests performed by the National Advisory Committee for Aeronautics to determine the effect on engine performance of directing the flow of the inlet air to a 5-inch by 7-inch cylinder, solid injection, compression ignition engine, After a few preliminary tests, comparative runs were made at a speed of 1500 r.p.m. with and without directed air flow. It was found that directing the flow of the inlet air toward the fuel injection valve gave steadier engine operation, and an appreciable increase in power, and decreased fuel consumption. The results indicate the possibility of improving the performance of a given type of combustion chamber without changing its shape and with no change in valve timing. They would also seem to prove that directional turbulence, set up before the inlet valve of a four-stroke cycle engine, continues in the engine cylinder throughout the compression stroke.

  10. An assessment of combustion products of spark ignition engines supplied by ethanol - gasoline blends

    NASA Astrophysics Data System (ADS)

    Uzuneanu, K.; Golgotiu, E.

    2016-08-01

    The causes of environmental pollution by internal combustion engines arise from the use of fuels containing bounded carbon, from the fact that combustion takes place on a cyclic basis and at high temperature. The first and the last causes are directly related to the fuel and therefore there is in principle a possibility to reduce pollution by acting upon the fuel used. The present paper deals with the comparison of the level of combustion products of a spark ignition engine supplied by gasoline and by a mixture of 10 % ethanol - 90% gasoline.

  11. Compression ignition engine having fuel system for non-sooting combustion and method

    DOEpatents

    Bazyn, Timothy; Gehrke, Christopher

    2014-10-28

    A direct injection compression ignition internal combustion engine includes a fuel system having a nozzle extending into a cylinder of the engine and a plurality of spray orifices formed in the nozzle. Each of the spray orifices has an inner diameter dimension of about 0.09 mm or less, and define inter-orifice angles between adjacent spray orifice center axes of about 36.degree. or greater such that spray plumes of injected fuel from each of the spray orifices combust within the cylinder according to a non-sooting lifted flame and gas entrainment combustion pattern. Related methodology is also disclosed.

  12. Performance of a High-Speed Compression-Ignition Engine Using Multiple Orifice Fuel Injection Nozzles

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Foster, H H

    1930-01-01

    This report presents test results obtained at the Langley Memorial Aeronautical Laboratory of the National Advisory Committee for Aeronautics during an investigation to determine the relative performance of a single-cylinder, high-speed, compression-ignition engine when using fuel injection valve nozzles with different numbers, sizes, and directions of round orifices. A spring-loaded, automatic injection valve was used, centrally located at the top of a vertical disk-type combustion chamber formed between horizontally opposed inlet and exhaust valves of a 5 inch by 7 inch engine.

  13. A stirling engine computer model for performance calculations

    NASA Technical Reports Server (NTRS)

    Tew, R.; Jefferies, K.; Miao, D.

    1978-01-01

    To support the development of the Stirling engine as a possible alternative to the automobile spark-ignition engine, the thermodynamic characteristics of the Stirling engine were analyzed and modeled on a computer. The modeling techniques used are presented. The performance of an existing rhombic-drive Stirling engine was simulated by use of this computer program, and some typical results are presented. Engine tests are planned in order to evaluate this model.

  14. Studies on exhaust emissions of catalytic coated spark ignition engine with adulterated gasoline.

    PubMed

    Muralikrishna, M V S; Kishor, K; Venkata Ramana Reddy, Ch

    2006-04-01

    Adulteration of automotive fuels, especially, gasoline with cheaper fuels is widespread throughout south Asia. Some adulterants decrease the performance and life of the engine and increase the emission of harmful pollutants causing environmental and health problems. The present investigation is carried out to study the exhaust emissions from a single cylinder spark ignition (SI) engine with kerosene blended gasoline with different versions of the engine, such as conventional engine and catalytic coated engine with different proportions of the kerosene ranging from 0% to 40% by volume in steps of 10% in the kerosene-gasoline blend. The catalytic coated engine used in the study has copper coating of thickness 400 microns on piston and inner surface of the cylinder head. The pollutants in the exhaust, carbon monoxide (CO) and unburnt hydrocarbons (UBHC) are measured with Netel Chromatograph CO and HC analyzer at peak load operation of the engine. The engine is provided with catalytic converter with sponge iron as a catalyst to control the pollutants from the exhaust of the engine. An air injection is also provided to the catalytic converter to further reduce the pollutants. The pollutants found to increase drastically with adulterated gasoline. Copper-coated engine with catalytic converter significantly reduced pollutants, when compared to conventional engine.

  15. A Simple HCCI Engine Model for Control

    SciTech Connect

    Killingsworth, N; Aceves, S; Flowers, D; Krstic, M

    2006-06-29

    The homogeneous charge compression ignition (HCCI) engine is an attractive technology because of its high efficiency and low emissions. However, HCCI lacks a direct combustion trigger making control of combustion timing challenging, especially during transients. To aid in HCCI engine control we present a simple model of the HCCI combustion process valid over a range of intake pressures, intake temperatures, equivalence ratios, and engine speeds. The model provides an estimate of the combustion timing on a cycle-by-cycle basis. An ignition threshold, which is a function of the in-cylinder motored temperature and pressure is used to predict start of combustion. This model allows the synthesis of nonlinear control laws, which can be utilized for control of an HCCI engine during transients.

  16. Devices to improve the performance of a conventional two-stroke spark ignition engine

    SciTech Connect

    Poola, R.B.; Nagalingam, B.; Gopalakrishnan, K.V.

    1995-06-01

    This paper presents research efforts made in three different phases with the objective of improving the fuel economy of and reducing exhaust emissions from conventional, carbureted, two-stroke spark ignition (SI) engines, which are widely employed in two-wheel transportation in India. A review concerning the existing two-stroke engine technology for this application is included. In the first phase, a new scavenging system was developed and tested to reduce the loss of fresh charge through the exhaust port. In die second phase, the following measures were carried out to improve the combustion process: (1) using an in-cylinder catalyst, such as copper, chromium, and nickel, in the form of coating; (2) providing moderate thermal insulation in the combustion chamber, either by depositing thin ceramic material or by metal inserts; (3) developing a high-energy ignition system; and (4) employing high-octane fuel, such as methanol, ethanol, eucalyptus oil, and orange oil, as a blending agent with gasoline. Based on the effectiveness of the above measures, an optimized design was developed in the final phase to achieve improved performance. Test results indicate that with an optimized two-stroke SI engine, the maximum percentage improvement in brake thermal efficiency is about 31%, together with a reduction of 3400 ppm in hydrocarbons (HC) and 3% by volume of carbon monoxide (CO) emissions over the normal engine (at 3 kW, 3000 rpm). Higher cylinder peak pressures (3-5 bar), lower ignition delay (2-4{degrees}CA){degrees} and shorter combustion duration (4-10 {degrees}CA) are obtained. The knock-limited power output is also enhanced by 12.7% at a high compression ratio (CR) of 9:1. The proposed modifications in the optimized design are simple, low-cost and easy to adopt for both production and existing engines.

  17. Very Low Thrust Gaseous Oxygen-hydrogen Rocket Engine Ignition Technology

    NASA Technical Reports Server (NTRS)

    Bjorklund, Roy A.

    1983-01-01

    An experimental program was performed to determine the minimum energy per spark for reliable and repeatable ignition of gaseous oxygen (GO2) and gaseous hydrogen (GH2) in very low thrust 0.44 to 2.22-N (0.10 to 0.50-lb sub f) rocket engines or spacecraft and satellite attitude control systems (ACS) application. Initially, the testing was conducted at ambient conditions, with the results subsequently verified under vacuum conditions. An experimental breadboard electrical exciter that delivered 0.2 to 0.3 mj per spark was developed and demonstrated by repeated ignitions of a 2.22-N (0.50-lb sub f) thruster in a vacuum chamber with test durations up to 30 min.

  18. Breakdown voltage determination of gaseous and near cryogenic fluids with application to rocket engine ignition

    NASA Astrophysics Data System (ADS)

    Nugent, Nicholas Jeremy

    Liquid rocket engines extensively use spark-initiated torch igniters for ignition. As the focus shifts to longer missions that require multiple starts of the main engines, there exists a need to solve the significant problems associated with using spark-initiated devices. Improving the fundamental understanding of predicting the required breakdown voltage in rocket environments along with reducing electrical noise is necessary to ensure that missions can be completed successfully. To better understand spark ignition systems and add to the fundamental research on spark development in rocket applications, several parameter categories of interest were hypothesized to affect breakdown voltage: (i) fluid, (ii) electrode, and (iii) electrical. The fluid properties varied were pressure, temperature, density and mass flow rate. Electrode materials, insert electrode angle and spark gap distance were the electrode properties varied. Polarity was the electrical property investigated. Testing how breakdown voltage is affected by each parameter was conducted using three different isolated insert electrodes fabricated from copper and nickel. A spark plug commonly used in torch igniters was the other electrode. A continuous output power source connected to a large impedance source and capacitance provided the pulsing potential. Temperature, pressure and high voltage measurements were recorded for the 418 tests that were successfully completed. Nitrogen, being inert and similar to oxygen, a propellant widely used in torch igniters, was used as the fluid for the majority of testing. There were 68 tests completed with oxygen and 45 with helium. A regression of the nitrogen data produced a correction coefficient to Paschen's Law that predicts the breakdown voltage to within 3000 volts, better than 20%, compared to an over prediction on the order of 100,000 volts using Paschen's Law. The correction coefficient is based on the parameters most influencing breakdown voltage: fluid

  19. Onboard Hydrogen Generation for a Spark Ignition Engine via Thermochemical Recuperation

    NASA Astrophysics Data System (ADS)

    Silva, Isaac Alexander

    A method of exhaust heat recovery from a spark-ignition internal combustion engine was explored, utilizing a steam reforming thermochemical reactor to produce a hydrogen-rich effluent, which was then consumed in the engine. The effects of hydrogen in the combustion process have been studied extensively, and it has been shown that an extension of the lean stability limit is possible through hydrogen enrichment. The system efficiency and the extension of the operational range of an internal combustion engine were explored through the use of a methane fueled naturally aspirated single cylinder engine co-fueled with syngas produced with an on board methane steam reformer. It was demonstrated that an extension of the lean stability limit is possible using this system.

  20. Feasibility demonstration of the Thermal Ignition Combustion System (TICS) for high-pressure natural-gas-injected engine

    SciTech Connect

    Kalwani, R.M.; McNulty, D.; Badgley, P.; Kamo, R.

    1989-02-01

    The objective of the program was the feasibility demonstration of the Thermal Ignition Combustion System (TICS) concept for the ignition and combustion of high-pressure injected natural gas. The TICS concept relies on the ignition of fuel by high-temperature combustion chamber walls without external ignition sources like spark plug, glow plug, or pilot diesel fuel. The program was successful in achieving ignition and combustion of natural gas in a single cylinder diesel engine with the TICS concept. An electronically controlled gas injector, designed and fabricated in the program, was used to inject natural gas at 13.8 to 20.7 MPa (2000 to 3000 psig) pressure in the TICS chamber. Cold starting of the test engine was achieved by external heating of the chamber for a few minutes. Natural gas ignition and combustion was then sustained by the high-temperature TICS chamber. The test engine was operated from idle to full load and from 600 to 1400 rpm engine-speed range.

  1. Premixed ignition behavior of C{sub 9} fatty acid esters: A motored engine study

    SciTech Connect

    Zhang, Yu.; Yang, Yi; Boehman, Andre L.

    2009-06-15

    An experimental study on the premixed ignition behavior of C{sub 9} fatty acid esters has been conducted in a motored CFR engine. For each test fuel, the engine compression ratio was gradually increased from the lowest point (4.43) to the point where significant high temperature heat release (HTHR) was observed. The engine exhaust was sampled and analyzed through GC-FID/TCD and GC-MS. Combustion analysis showed that the four C{sub 9} fatty acid esters tested in this study exhibited evidently different ignition behavior. The magnitude of low temperature heat release (LTHR) follows the order, ethyl nonanoate > methyl nonanoate >> methyl 2-nonenoate > methyl 3-nonenoate. The lower oxidation reactivity for the unsaturated fatty acid esters in the low temperature regime can be explained by the reduced amount of six- or seven-membered transition state rings formed during the oxidation of the unsaturated esters due to the presence of a double bond in the aliphatic chain of the esters. The inhibition effect of the double bond on the low temperature oxidation reactivity of fatty acid esters becomes more pronounced as the double bond moves toward the central position of the aliphatic chain. GC-MS analysis of exhaust condensate collected under the engine conditions where only LTHR occurred showed that the alkyl chain of the saturated fatty acid esters participated in typical paraffin-like low temperature oxidation sequences. In contrast, for unsaturated fatty acid esters, the autoignition can undergo olefin ignition pathways. For all test compounds, the ester functional group remains largely intact during the early stage of oxidation. (author)

  2. Experimental investigation of gasoline compression ignition combustion in a light-duty diesel engine

    NASA Astrophysics Data System (ADS)

    Loeper, C. Paul

    Due to increased ignition delay and volatility, low temperature combustion (LTC) research utilizing gasoline fuel has experienced recent interest [1-3]. These characteristics improve air-fuel mixing prior to ignition allowing for reduced emissions of nitrogen oxides (NOx) and soot (or particulate matter, PM). Computational fluid dynamics (CFD) results at the University of Wisconsin-Madison's Engine Research Center (Ra et al. [4, 5]) have validated these attributes and established baseline operating parameters for a gasoline compression ignition (GCI) concept in a light-duty diesel engine over a large load range (3-16 bar net IMEP). In addition to validating these computational results, subsequent experiments at the Engine Research Center utilizing a single cylinder research engine based on a GM 1.9-liter diesel engine have progressed fundamental understanding of gasoline autoignition processes, and established the capability of critical controlling input parameters to better control GCI operation. The focus of this thesis can be divided into three segments: 1) establishment of operating requirements in the low-load operating limit, including operation sensitivities with respect to inlet temperature, and the capabilities of injection strategy to minimize NOx emissions while maintaining good cycle-to-cycle combustion stability; 2) development of novel three-injection strategies to extend the high load limit; and 3) having developed fundamental understanding of gasoline autoignition kinetics, and how changes in physical processes (e.g. engine speed effects, inlet pressure variation, and air-fuel mixture processes) affects operation, develop operating strategies to maintain robust engine operation. Collectively, experimental results have demonstrated the ability of GCI strategies to operate over a large load-speed range (3 bar to 17.8 bar net IMEP and 1300-2500 RPM, respectively) with low emissions (NOx and PM less than 1 g/kg-FI and 0.2 g/kg-FI, respectively), and low

  3. Effects of Fuel Laminar Flame Speed Compared to Engine Tumble Ratio, Ignition Energy, and Injection Strategy on Lean and EGR Dilute Spark Ignition Combustion

    DOE PAGES

    Kolodziej, Christopher P.; Pamminger, Michael; Sevik, James; ...

    2017-03-28

    Previously we show that fuels with higher laminar flame speed also have increased tolerance to EGR dilution. In this work, the effects of fuel laminar flame speed on both lean and EGR dilute spark ignition combustion stability were examined. Fuels blends of pure components (iso-octane, n-heptane, toluene, ethanol, and methanol) were derived at two levels of laminar flame speed. Each fuel blend was tested in a single-cylinder spark-ignition engine under both lean-out and EGR dilution sweeps until the coefficient of variance of indicated mean effective pressure increased above thresholds of 3% and 5%. The relative importance of fuel laminar flamemore » speed to changes to engine design parameters (spark ignition energy, tumble ratio, and port vs. direct injection) was also assessed. Our results showed that fuel laminar flame speed can have as big an effect on lean or EGR dilute engine operation as engine design parameters, with the largest effects seen during EGR dilute operation and when changes were made to cylinder charge motion.« less

  4. Experimental cross-correlation nitrogen Q-branch CARS thermometry in a spark ignition engine

    NASA Astrophysics Data System (ADS)

    Lockett, R. D.; Ball, D.; Robertson, G. N.

    2013-07-01

    A purely experimental technique was employed to derive temperatures from nitrogen Q-branch Coherent Anti-Stokes Raman Scattering (CARS) spectra, obtained in a high pressure, high temperature environment (spark ignition Otto engine). This was in order to obviate any errors arising from deficiencies in the spectral scaling laws which are commonly used to represent nitrogen Q-branch CARS spectra at high pressure. The spectra obtained in the engine were compared with spectra obtained in a calibrated high pressure, high temperature cell, using direct cross-correlation in place of the minimisation of sums of squares of residuals. The technique is demonstrated through the measurement of air temperature as a function of crankshaft angle inside the cylinder of a motored single-cylinder Ricardo E6 research engine, followed by the measurement of fuel-air mixture temperatures obtained during the compression stroke in a knocking Ricardo E6 engine. A standard CARS programme (SANDIA's CARSFIT) was employed to calibrate the altered non-resonant background contribution to the CARS spectra that was caused by the alteration to the mole fraction of nitrogen in the unburned fuel-air mixture. The compression temperature profiles were extrapolated in order to predict the auto-ignition temperatures.

  5. Premixed ignition behavior of alternative diesel fuel-relevant compounds in a motored engine experiment

    SciTech Connect

    Szybist, James P.; Boehman, Andre L.; Haworth, Daniel C.; Koga, Hibiki

    2007-04-15

    A motored engine study using premixed charges of fuel and air at a wide range of diesel-relevant equivalence ratios was performed to investigate autoignition differences among surrogates for conventional diesel fuel, gas-to-liquid (GTL) diesel fuel, and biodiesel, as well as n-heptane. Experiments were performed by delivering a premixed charge of vaporized fuel and air and increasing the compression ratio in a stepwise manner to increase the extent of reaction while monitoring the exhaust composition via Fourier transform infrared (FTIR) spectrometry and collecting condensable exhaust gas for subsequent gas chromatography/mass spectrometry (GC/MS) analysis. Each fuel demonstrated a two-stage ignition process, with a low-temperature heat release (LTHR) event followed by the main combustion, or high-temperature heat release (HTHR). Among the three diesel-relevant fuels, the magnitude of LTHR was highest for GTL diesel, followed by methyl decanoate, and conventional diesel fuel last. FTIR analysis of the exhaust for n-heptane, the conventional diesel surrogate, and the GTL diesel surrogate revealed that LTHR produces high concentrations of aldehydes and CO while producing only negligible amounts of CO{sub 2}. Methyl decanoate differed from the other two-stage ignition fuels only in that there were significant amounts of CO{sub 2} produced during LTHR; this was the result of decarboxylation of the ester group, not the result of oxidation. GC/MS analysis of LTHR exhaust condensate for n-heptane revealed high concentrations of 2,5-heptanedione, a di-ketone that can be closely tied to species in existing autoignition models for n-heptane. GC/MS analysis of the LTHR condensate for conventional diesel fuel and GTL diesel fuel revealed a series of high molecular weight aldehydes and ketones, which were expected, as well as a series of organic acids, which are not commonly reported as products of combustion. The GC/MS analysis of the methyl decanoate exhaust condensate

  6. Characteristic time ignition model extended to an annular gas turbine combustor

    SciTech Connect

    Peters, J.E.; Mellor, A.M.

    1982-11-01

    The extension of the ignition model to an annular combustor was successful and a single ignition limit curve for three engines was developed. The correlation also includes 4 geometries and 2 plug locations for the AGT-1500, 30 fuels covering a wide range of volatilities from gasoline to No. 6 fuel oil and viscosities of 0.3-75 x 10/sup -6/ m/sup 2//s, inlet air temperatures of 240-330 K, and pressures of 30-140 kPa. One significant difference that developed in examining the F101 data is that the primary zone equivalence ratio was the proper equivalence ration for the F101 as opposed to the assumption of a constant equivalence ratio at the spark gap for the AGT-1500 and T-63. This may indicate better mixing of the fuel spray with the primary zone air in the F101 due to the injection of the fuel into the primary and secondary swirler air. The critical features of applying the ignition model to gas turbine combustors are the drop size estimates via empirical equations and the equivalence ratio evaluations based on the fuel spray and spark plug locations.

  7. Evaluation and Characterization Study of Dual Pulse Laser-Induced Spark (DPLIS) for Rocket Engine Ignition System Application

    NASA Technical Reports Server (NTRS)

    Osborne, Robin; Wehrmeyer, Joseph; Trinh, Huu; Early, James

    2003-01-01

    This paper addresses the progress of technology development of a laser ignition system at NASA Marshall Space Flight Center (MSFC). Laser ignition has been used at MSFC in recent test series to successfully ignite RP1/GOX propellants in a subscale rocket chamber, and other past studies by NASA GRC have demonstrated the use of laser ignition for rocket engines. Despite the progress made in the study of this ignition method, the logistics of depositing laser sparks inside a rocket chamber have prohibited its use. However, recent advances in laser designs, the use of fiber optics, and studies of multi-pulse laser formats3 have renewed the interest of rocket designers in this state-of the-art technology which offers the potential elimination of torch igniter systems and their associated mechanical parts, as well as toxic hypergolic ignition systems. In support of this interest to develop an alternative ignition system that meets the risk-reduction demands of Next Generation Launch Technology (NGLT), characterization studies of a dual pulse laser format for laser-induced spark ignition are underway at MSFC. Results obtained at MSFC indicate that a dual pulse format can produce plasmas that absorb the laser energy as efficiently as a single pulse format, yet provide a longer plasma lifetime. In an experiments with lean H2/air propellants, the dual pulse laser format, containing the same total energy of a single laser pulse, produced a spark that was superior in its ability to provide sustained ignition of fuel-lean H2/air propellants. The results from these experiments are being used to optimize a dual pulse laser format for future subscale rocket chamber tests. Besides the ignition enhancement, the dual pulse technique provides a practical way to distribute and deliver laser light to the combustion chamber, an important consideration given the limitation of peak power that can be delivered through optical fibers. With this knowledge, scientists and engineers at Los

  8. A Laser Spark Plug Ignition System for a Stationary Lean-Burn Natural Gas Reciprocating Engine

    SciTech Connect

    McIntyre, D. L.

    2007-05-01

    To meet the ignition system needs of large bore, high pressure, lean burn, natural gas engines a side pumped, passively Q-switched, Nd:YAG laser was developed and tested. The laser was designed to produce the optical intensities needed to initiate ignition in a lean burn, high compression engine. The laser and associated optics were designed with a passive Q-switch to eliminate the need for high voltage signaling and associated equipment. The laser was diode pumped to eliminate the need for high voltage flash lamps which have poor pumping efficiency. The independent and dependent parameters of the laser were identified and explored in specific combinations that produced consistent robust sparks in laboratory air. Prior research has shown that increasing gas pressure lowers the breakdown threshold for laser initiated ignition. The laser has an overall geometry of 57x57x152 mm with an output beam diameter of approximately 3 mm. The experimentation used a wide range of optical and electrical input parameters that when combined produced ignition in laboratory air. The results show a strong dependence of the output parameters on the output coupler reflectivity, Q-switch initial transmission, and gain media dopant concentration. As these three parameters were lowered the output performance of the laser increased leading to larger more brilliant sparks. The results show peak power levels of up to 3MW and peak focal intensities of up to 560 GW/cm2. Engine testing was performed on a Ricardo Proteus single cylinder research engine. The goal of the engine testing was to show that the test laser performs identically to the commercially available flashlamp pumped actively Q-switched laser used in previous laser ignition testing. The engine testing consisted of a comparison of the in-cylinder, and emissions behavior of the engine using each of the lasers as an ignition system. All engine parameters were kept as constant as possilbe while the equivalence ratio (fueling

  9. A Model based Examination of Conditions for Ignition of Turbidity Currents on Slopes

    NASA Astrophysics Data System (ADS)

    Mehta, A. J.; Krishna, G.

    2009-12-01

    Turbidity currents form a major mechanism for the movement of sediment in the natural environment. Self-accelerating turbidity currents over continental slopes are of considerable scientific and engineering interest due to their role as agents for submarine sediment transportation from the shelf to the seabed. Such currents are called ignitive provided they eventually reach a catastrophic state as acceleration results in high sediment loads due to erosion of the sloping bed. A numerical model, which treats the fluid and the particles as two separate phases, is applied to investigate the effects of particle size, initial flow friction velocity and mild bed slope on the ignitive condition. Laboratory experimental data have been included as part of the analysis for qualitative comparison purposes. Ignition for the smallest of the three selected sizes (0.21mm) of medium sand typical of Florida beaches was found to depend on the initial conditions at the head of the slope as determined by the pressure gradient. Bed slope seemed to be of secondary importance. For the two sands with larger grain sizes (0.28mm and 0.35mm) the slope was found to play a more important role when compared to the initial pressure gradient. For a given pressure gradient, increasing the slope increased the likelihood of self-acceleration. It is concluded that in general ignition cannot be defined merely in terms of positive values of the velocity gradient and the sediment flux gradient along the slope. Depending on particle size the initial pressure gradient can also play a role. For the selected initial conditions (grain size, pressure gradient and bed slope), out of the 54 combinations tested, all except three satisfied the Knapp-Bagnold criterion for auto-suspension irrespective of whether the turbid current was ignitive or non-ignitive. In all 54 cases the current was found to erode the bed. Further use of the model will require accommodation of wider ranges of sediment size and bed density

  10. Effects of ignition location models on the burn patterns of simulated wildfires

    USGS Publications Warehouse

    Bar-Massada, A.; Syphard, A.D.; Hawbaker, T.J.; Stewart, S.I.; Radeloff, V.C.

    2011-01-01

    Fire simulation studies that use models such as FARSITE often assume that ignition locations are distributed randomly, because spatially explicit information about actual ignition locations are difficult to obtain. However, many studies show that the spatial distribution of ignition locations, whether human-caused or natural, is non-random. Thus, predictions from fire simulations based on random ignitions may be unrealistic. However, the extent to which the assumption of ignition location affects the predictions of fire simulation models has never been systematically explored. Our goal was to assess the difference in fire simulations that are based on random versus non-random ignition location patterns. We conducted four sets of 6000 FARSITE simulations for the Santa Monica Mountains in California to quantify the influence of random and non-random ignition locations and normal and extreme weather conditions on fire size distributions and spatial patterns of burn probability. Under extreme weather conditions, fires were significantly larger for non-random ignitions compared to random ignitions (mean area of 344.5 ha and 230.1 ha, respectively), but burn probability maps were highly correlated (r = 0.83). Under normal weather, random ignitions produced significantly larger fires than non-random ignitions (17.5 ha and 13.3 ha, respectively), and the spatial correlations between burn probability maps were not high (r = 0.54), though the difference in the average burn probability was small. The results of the study suggest that the location of ignitions used in fire simulation models may substantially influence the spatial predictions of fire spread patterns. However, the spatial bias introduced by using a random ignition location model may be minimized if the fire simulations are conducted under extreme weather conditions when fire spread is greatest. ?? 2010 Elsevier Ltd.

  11. Increasing the Air Charge and Scavenging the Clearance Volume of a Compression-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Hicks, C W; Foster, H H

    1934-01-01

    The object of the investigation presented in this report was to determine the effects of increasing the air charge and scavenging the clearance volume of a 4-stroke-cycle compression-ignition engine having a vertical-disk form combustion chamber. Boosting the inlet-air pressure with normal valve timing increased the indicated engine power in proportion to the additional air inducted and resulted in smoother engine operation with less combustion shock. Scavenging the clearance volume by using a valve overlap of 145 degrees and an inlet-air boost pressure of approximately 2 1/2 inches of mercury produced a net increase in performance for clear exhaust operation of 33 percent over that obtained with normal valve timing and the same boost pressure. The improved combustion characteristics result in lower specific fuel consumption, and a clearer exhaust.

  12. Fuel Spray and Flame Formation in a Compression-Ignition Engine Employing Air Flow

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Waldron, C D

    1937-01-01

    The effects of air flow on fuel spray and flame formation in a high-speed compression-ignition engine have been investigated by means of the NACA combustion apparatus. The process was studied by examining high-speed motion pictures taken at the rate of 2,200 frames a second. The combustion chamber was of the flat-disk type used in previous experiments with this apparatus. The air flow was produced by a rectangular displacer mounted on top of the engine piston. Three fuel-injection nozzles were tested: a 0.020-inch single-orifice nozzle, a 6-orifice nozzle, and a slit nozzle. The air velocity within the combustion chamber was estimated to reach a value of 425 feet a second. The results show that in no case was the form of the fuel spray completely destroyed by the air jet although in some cases the direction of the spray was changed and the spray envelope was carried away by the moving air. The distribution of the fuel in the combustion chamber of a compression-ignition engine can be regulated to some extent by the design of the combustion chamber, by the design of the fuel-injection nozzle, and by the use of air flow.

  13. Space Launch System Scale Model Acoustic Test Ignition Overpressure Testing

    NASA Technical Reports Server (NTRS)

    Nance, Donald K.; Liever, Peter A.

    2015-01-01

    The overpressure phenomenon is a transient fluid dynamic event occurring during rocket propulsion system ignition. This phenomenon results from fluid compression of the accelerating plume gas, subsequent rarefaction, and subsequent propagation from the exhaust trench and duct holes. The high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and surrounding structure. Commonly known as ignition overpressure (IOP), this is an important design-to environment for the Space Launch System (SLS) that NASA is currently developing. Subscale testing is useful in validating and verifying the IOP environment. This was one of the objectives of the Scale Model Acoustic Test (SMAT), conducted at Marshall Space Flight Center (MSFC). The test data quantifies the effectiveness of the SLS IOP suppression system and improves the analytical models used to predict the SLS IOP environments. The reduction and analysis of the data gathered during the SMAT IOP test series requires identification and characterization of multiple dynamic events and scaling of the event waveforms to provide the most accurate comparisons to determine the effectiveness of the IOP suppression systems. The identification and characterization of the overpressure events, the waveform scaling, the computation of the IOP suppression system knockdown factors, and preliminary comparisons to the analytical models are discussed.

  14. Space Launch System Scale Model Acoustic Test Ignition Overpressure Testing

    NASA Technical Reports Server (NTRS)

    Nance, Donald; Liever, Peter; Nielsen, Tanner

    2015-01-01

    The overpressure phenomenon is a transient fluid dynamic event occurring during rocket propulsion system ignition. This phenomenon results from fluid compression of the accelerating plume gas, subsequent rarefaction, and subsequent propagation from the exhaust trench and duct holes. The high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and surrounding structure. Commonly known as ignition overpressure (IOP), this is an important design-to environment for the Space Launch System (SLS) that NASA is currently developing. Subscale testing is useful in validating and verifying the IOP environment. This was one of the objectives of the Scale Model Acoustic Test, conducted at Marshall Space Flight Center. The test data quantifies the effectiveness of the SLS IOP suppression system and improves the analytical models used to predict the SLS IOP environments. The reduction and analysis of the data gathered during the SMAT IOP test series requires identification and characterization of multiple dynamic events and scaling of the event waveforms to provide the most accurate comparisons to determine the effectiveness of the IOP suppression systems. The identification and characterization of the overpressure events, the waveform scaling, the computation of the IOP suppression system knockdown factors, and preliminary comparisons to the analytical models are discussed.

  15. STS-55 pad abort: Engine 2011 oxidizer preburner augmented spark igniter check valve leak

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The STS-55 initial launch attempt of Columbia (OV102) was terminated on KSC launch pad A March 22, 1993 at 9:51 AM E.S.T. due to violation of an ME-3 (Engine 2011) Launch Commit Criteria (LCC) limit exceedance. The event description and timeline are summarized. Propellant loading was initiated on 22 March, 1993 at 1:15 AM EST. All SSME chill parameters and launch commit criteria (LCC) were nominal. At engine start plus 1.44 seconds, a Failure Identification (FID) was posted against Engine 2011 for exceeding the 50 psia Oxidizer Preburner (OPB) purge pressure redline. The engine was shut down at 1.50 seconds followed by Engines 2034 and 2030. All shut down sequences were nominal and the mission was safely aborted. The OPB purge pressure redline violation and the abort profile/overlay for all three engines are depicted. SSME Avionics hardware and software performed nominally during the incident. A review of vehicle data table (VDT) data and controller software logic revealed no failure indications other than the single FID 013-414, OPB purge pressure redline exceeded. Software logic was executed according to requirements and there was no anomalous controller software operation. Immediately following the abort, a Rocketdyne/NASA failure investigation team was assembled. The team successfully isolated the failure cause to the oxidizer preburner augmented spark igniter purge check valve not being fully closed due to contamination. The source of the contaminant was traced to a cut segment from a rubber O-ring which was used in a fine clean tool during valve production prior to 1992. The valve was apparently contaminated during its fabrication in 1985. The valve had performed acceptably on four previous flights of the engine, and SSME flight history shows 780 combined check valve flights without failure. The failure of an Engine 3 (SSME No. 2011) check valve to close was sensed by onboard engine instruments even though all other engine operations were normal. This

  16. STS-55 pad abort: Engine 2011 oxidizer preburner augmented spark igniter check valve leak

    NASA Astrophysics Data System (ADS)

    1993-03-01

    The STS-55 initial launch attempt of Columbia (OV102) was terminated on KSC launch pad A March 22, 1993 at 9:51 AM E.S.T. due to violation of an ME-3 (Engine 2011) Launch Commit Criteria (LCC) limit exceedance. The event description and timeline are summarized. Propellant loading was initiated on 22 March, 1993 at 1:15 AM EST. All SSME chill parameters and launch commit criteria (LCC) were nominal. At engine start plus 1.44 seconds, a Failure Identification (FID) was posted against Engine 2011 for exceeding the 50 psia Oxidizer Preburner (OPB) purge pressure redline. The engine was shut down at 1.50 seconds followed by Engines 2034 and 2030. All shut down sequences were nominal and the mission was safely aborted. The OPB purge pressure redline violation and the abort profile/overlay for all three engines are depicted. SSME Avionics hardware and software performed nominally during the incident. A review of vehicle data table (VDT) data and controller software logic revealed no failure indications other than the single FID 013-414, OPB purge pressure redline exceeded. Software logic was executed according to requirements and there was no anomalous controller software operation. Immediately following the abort, a Rocketdyne/NASA failure investigation team was assembled. The team successfully isolated the failure cause to the oxidizer preburner augmented spark igniter purge check valve not being fully closed due to contamination. The source of the contaminant was traced to a cut segment from a rubber O-ring which was used in a fine clean tool during valve production prior to 1992. The valve was apparently contaminated during its fabrication in 1985. The valve had performed acceptably on four previous flights of the engine, and SSME flight history shows 780 combined check valve flights without failure. The failure of an Engine 3 (SSME No. 2011) check valve to close was sensed by onboard engine instruments even though all other engine operations were normal. This

  17. Modeling the Shock Ignition of a Copper Oxide Aluminum Thermite

    NASA Astrophysics Data System (ADS)

    Lee, Kibaek; Stewart, D. Scott; Clemenson, Michael; Glumac, Nick; Murzyn, Christopher

    2015-06-01

    An experimental ``striker confinement'' shock compression test was developed in the Glumac-group at the University of Illinois to study ignition and reaction in composite reactive materials. These include thermitic and intermetallic reactive powders. The test places a sample of materials such as a thermite mixture of copper oxide and aluminum powders that are initially compressed to about 80 percent full density. Two RP-80 detonators simultaneously push steel bars into reactive material and the resulting compression causes shock compaction of the material and rapid heating. At that point one observes significant reaction and propagation of fronts. But the fronts are peculiar in that they are comprised of reactive events that can be traced to the reaction/diffusion of the initially separated reactants of copper oxide and aluminum that react at their mutual interfaces that nominally make copper liquid and aluminum oxide products. We discuss our model of the shock ignition of the copper oxide aluminum thermite in the context of the striker experiment and how a Gibbs formulation model, that includes multi-components for liquid and solid phases of aluminum, copper oxide, copper and aluminum oxide can predict the events observed at the particle scale in the experiments. Supported by HDTRA1-10-1-0020 (DTRA), N000014-12-1-0555 (ONR).

  18. Modeling the ignition of a copper oxide aluminum thermite

    NASA Astrophysics Data System (ADS)

    Lee, Kibaek; Stewart, D. Scott; Clemenson, Michael; Glumac, Nick; Murzyn, Christopher

    2017-01-01

    An experimental "striker confinement" shock compression experiment was developed in the Glumac-group at the University of Illinois to study ignition and reaction in composite reactive materials. These include thermitic and intermetallic reactive powders. Sample of materials such as a thermite mixture of copper oxide and aluminum powders are initially compressed to about 80 percent full density. Two RP-80 detonators simultaneously push steel bars into the reactive material and the resulting compression causes shock compaction of the material and rapid heating. At that point one observes significant reaction and propagation of fronts. But the fronts are peculiar in that they are comprised of reactive events that can be traced to the reaction of the initially separated reactants of copper oxide and aluminum that react at their mutual interfaces, that nominally make copper liquid and aluminum oxide products. We discuss our model of the ignition of the copper oxide aluminum thermite in the context of the striker experiment and how a Gibbs formulation model [1], that includes multi-components for liquid and solid phases of aluminum, copper oxide, copper and aluminum oxide, can predict the events observed at the particle scale in the experiments.

  19. Laser-Induced Ignition Modeling and Comparison with Experiments

    NASA Astrophysics Data System (ADS)

    Dors, Ivan; Qin, W.; Chen, Y.-L.; Parigger, C.; Lewis, J. W. L.

    2000-11-01

    We have studied experimentally the ignition resulting from optical breakdowns in mixtures of oxygen and the fuel ammonia induced by a 10 nanosecond pulsewidth laser for a time of hundreds of milliseconds using laser spectroscopy. In these studies, we have for the first time characterized the laser-induced plasma, the formation of the combustion radicals, the detonation wave, the flame front and the combustion process itself. The objective of the modeling is to understand the fluid dynamic and chemical kinetic effects following the nominal 10 ns laser pulse until 1 millisecond after laser breakdown. The calculated images match the experimentally recorded data sets and show spatial details covering volumes of 1/10000 cc to 1000 cc. The code was provided by CFD Research Corporation of Huntsville, Alabama, and was appropriately augmented to compute the observed phenomena. The fully developed computational model now includes a kinetic mechanism that implements plasma equilibrium kinetics in ionized regions, and non-equilibrium, multistep, finite rate reactions in non-ionized regions. The predicted fluid phenomena agree with various flow patterns characteristic of laser spark ignition as measured in the CLA laboratories. Comparison of calculated and measured OH and NH concentration will be presented.

  20. Gaseous and Particulate Matter Emissions of a Supercharged Spark Ignited Hydrogen Fueled Internal Combustion Engine

    NASA Astrophysics Data System (ADS)

    Kieran, Sean

    A spark ignited hydrogen fueled engine was operated at three equivalence ratios (0.4, 0.5, and 0.6) with a supercharger. During steady-state road load conditions, the engine produced exceptionally low unburned hydrocarbon, carbon monoxide, carbon dioxide, and particulate matter emissions. The oxides of nitrogen (NOx) emissions of the supercharged engine were 31.4, 149.5, and 787.0 mg*NOx/km for the equivalence ratios 0.4, 0.5, and 0.6 respectively. Given that the current EPA regulations are 99.4 mg*NOx/km, this engine configuration represents a possible replacement option for gasoline fueled engines without the need for exhaust after treatment. During engine start-up, some of the supercharged tests exhibited particulate matter emission spikes. These particulate matter spikes do not seem to be related to equivalence ratio, coolant temperature, testing order, or start-up acceleration. Currently, there is no explanation why some of the tests produced particulate matter during engine start-up and others did not.

  1. An investigation of the acoustic characteristics of a compression ignition engine operating with biodiesel blends

    NASA Astrophysics Data System (ADS)

    Zhen, D.; Tesfa, B.; Yuan, X.; Wang, R.; Gu, F.; Ball, A. D.

    2012-05-01

    In this paper, an experimental investigation has been carried out on the acoustic characteristics of a compression ignition (CI) engine running with biodiesel blends under steady state operating conditions. The experiment was conducted on a four-cylinder, four-stroke, direct injection and turbocharged diesel engine which runs with biodiesel (B50 and B100) and pure diesel. The signals of acoustic, vibration and in-cylinder pressure were measured during the experiment. To correlate the combustion process and the acoustic characteristics, both phenomena have been investigated. The acoustic analysis resulted in the sound level being increased with increasing of engine loads and speeds as well as the sound characteristics being closely correlated to the combustion process. However, acoustic signals are highly sensitive to the ambient conditions and intrusive background noise. Therefore, the spectral subtraction was employed to minimize the effects of background noise in order to enhance the signal to noise ratio. In addition, the acoustic characteristics of CI engine running with different fuels (biodiesel blends and diesel) was analysed for comparison. The results show that the sound energy level of acoustic signals is slightly higher when the engine fuelled by biodiesel and its blends than that of fuelled by normal diesel. Hence, the acoustic characteristics of the CI engine will have useful information for engine condition monitoring and fuel content estimation.

  2. Analysis of an Increase in the Efficiency of a Spark Ignition Engine Through the Application of an Automotive Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Merkisz, Jerzy; Fuc, Pawel; Lijewski, Piotr; Ziolkowski, Andrzej; Galant, Marta; Siedlecki, Maciej

    2016-08-01

    We have analyzed the increase of the overall efficiency of a spark ignition engine through energy recovery following the application of an automotive thermoelectric generator (ATEG) of our own design. The design of the generator was developed following emission investigations during vehicle driving under city traffic conditions. The measurement points were defined by actual operation conditions (engine speed and load), subsequently reproduced on an engine dynamometer. Both the vehicle used in the on-road tests and the engine dynamometer were fit with the same, downsized spark ignition engine (with high effective power-to-displacement ratio). The thermodynamic parameters of the exhaust gases (temperature and exhaust gas mass flow) were measured on the engine testbed, along with the fuel consumption and electric current generated by the thermoelectric modules. On this basis, the power of the ATEG and its impact on overall engine efficiency were determined.

  3. Optical Propagation Modeling for the National Ignition Facility

    SciTech Connect

    Williams, W H; Auerbach, J M; Henesian, M A; Jancaitis, K S; Manes, K R; Mehta, N C; Orth, C D; Sacks, R A; Shaw, M J; Widmayer, C C

    2004-01-12

    Optical propagation modeling of the National Ignition Facility has been utilized extensively from conceptual design several years ago through to early operations today. In practice we routinely (for every shot) model beam propagation starting from the waveform generator through to the target. This includes the regenerative amplifier, the 4-pass rod amplifier, and the large slab amplifiers. Such models have been improved over time to include details such as distances between components, gain profiles in the laser slabs and rods, transient optical distortions due to the flashlamp heating of laser slabs, measured transmitted and reflected wavefronts for all large optics, the adaptive optic feedback loop, and the frequency converter. These calculations allow nearfield and farfield predictions in good agreement with measurements.

  4. Performance and Operational Modeling of the National Ignition Facility

    SciTech Connect

    Shaw, M; Williams, W; Jancaitis, K; Widmayer, C; House, R

    2003-07-01

    The National Ignition Facility (NIF), currently under construction at the University of California's Lawrence Livermore National Laboratory (LLNL) is a stadium-sized facility containing a 192-beam, 1.8 Megajoule, 500-Terrawatt, 351-nm laser system together with a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. NIF is being built by the National Nuclear Security Administration and when completed will be the world's largest laser experimental system, providing a national center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIF's 192 energetic laser beams will compress fusion targets to conditions where they will ignite and burn, liberating more energy than required to initiate the fusion reaction. The first four beamlines (a quad) are currently being commissioned, with increasingly energetic laser pulses being propagated throughout the laser system. Success on many of the NIF laser's missions depends on obtaining precisely specified energy waveforms from each of the 192 beams over a wide variety of pulse lengths and temporal shapes. A computational system, the Laser Performance Operations Model (LPOM) has been developed and deployed during NIF commissioning to automate the laser setup process, and accurately predict laser energetics. For each shot on NIF, the LPOM determines the characteristics of the injection laser system required to achieve the desired main laser output, provides parameter checking for equipment protection, determines the required diagnostic setup, and supplies post-shot data analysis and reporting.

  5. Coefficients of discharge of fuel-injection nozzles for compression-ignition engines

    NASA Technical Reports Server (NTRS)

    Gelalles, A G

    1932-01-01

    This report presents the results of an investigation to determine the coefficients of discharge of nozzles with small, round orifices of the size used with high-speed compression-ignition engines. The injection pressures and chamber back pressures employed were comparable to those existing in compression-ignition engines during injection. The construction of the nozzles was varied to determine the effect of the nozzle design on the coefficient. Tests were also made with nozzles assembled in an automatic injection valve, both with a plain and with a helically grooved stem. It was found that a smooth passage before the orifice is requisite for high flow efficiency. A beveled leading edge before the orifice gave a higher coefficient of discharge than a rounded edge. The results with the nozzles assembled in an automatic injection valve having a plain stem duplicated those with the nozzles assembled at the end of a straight tube of constant diameter. Lower coefficients were obtained with the nozzles assembled in an injection valve having a helically grooved stem. When the coefficients of nozzles of any one geometrical shape were plotted against values of corresponding Reynold's numbers for the orifice diameters and rates of flow tested, it was found that experimental points were distributed along a single curve.

  6. Emission of a compression ignition engine fuelled by diesel and imitated syngas

    NASA Astrophysics Data System (ADS)

    Mahgoub, Bahaaddein Kamal M.; Sulaiman, S. A.; Karim, Zainal Ambri B. A.

    2012-06-01

    Biomass can be converted into a useful source of energy through gasification. The gasification product, known as synthesis gas or syngas, composition of syngas may fluctuate due to many factors such as operational errors of the gasifier as well as the type of feedstock used or may be due to the feeding rate fluctuation. Therefore it would be difficult to assess the effect of syngas composition and diesel replacement ratio to the emission when combusted in dual fuel syngas - diesel compression ignition engine. In order to overcome this problem controllable composition and conditions of imitated syngas was used in this study by selective three compositions of syngas close to the real conditions. The objective of this study is to determine the exhaust emissions of a compression ignition engine fuelled with diesel and imitated syngas at different compositions and diesel replacement ratios to determine the most appropriate composition of syngas and diesel replacement ratio which will give less emission. The test results on syngas emission are compared with the results of diesel. CO2 and NOX emission level was reduced on syngas dual fuel mode, but there were increases in CO and THC emissions throughout all syngas compositions examined due to poor combustion efficiency of dual fuel operation.

  7. A Home Ignition Assessment Model Applied to Structures in the Wildland-Urban Interface

    SciTech Connect

    Biswas, Kaushik; Werth, David; Gupta, Narendra

    2013-01-01

    The issue of exterior fire threat to buildings, from either wildfires in the wildland-urban interface or neighboring structure fires, is critically important. To address this, theWildfire Ignition Resistant Home Design (WIRHD) program was initiated. The WIRHD program developed a tool, theWildFIREWizard, that will allow homeowners to estimate the external fire threat to their homes based on specific features and characteristics of the homes and yards. The software then makes recommendations to reduce the threat. The inputs include the structural and material features of the home and information about any ignition sources or flammable objects in its immediate vicinity, known as the home ignition zone. The tool comprises an ignition assessment model that performs explicit calculations of the radiant and convective heating of the building envelope from the potential ignition sources. This article describes a series of material ignition and flammability tests that were performed to calibrate and/or validate the ignition assessment model. The tests involved exposing test walls with different external siding types to radiant heating and/or direct flame contact.The responses of the test walls were used to determine the conditions leading to melting, ignition, or any other mode of failure of the walls. Temperature data were used to verify the model predictions of temperature rises and ignition times of the test walls.

  8. Preknock Vibrations in a Spark-Ignition Engine Cylinder as Revealed by High-Speed Photography

    NASA Technical Reports Server (NTRS)

    Miller, Cearcy D; Logan, Walter O , Jr

    1944-01-01

    The high-speed photographic investigation of the mechanics of spark-ignition engine knock recorded in three previous reports has been extended with use of the NACA high-speed camera and combustion apparatus with a piezoelectric pressure pickup in the combustion chamber. The motion pictures of knocking combustion were taken at the rate of 40,000 frames per second. Existence of the preknock vibrations in the engine cylinder suggested in Technical Report no.727 has been definitely proved and the vibrations have been analyzed both in the high-speed motion pictures and the pressure traces. Data are also included to show that the preknock vibrations do not progressively build up to cause knock. The effect of tetraethyl lead on the preknock vibrations has been studied and results of the tests are presented. Photographs are presented which in some cases clearly show evidence of autoignition in the end zone a considerable length of time before knock occurs.

  9. On the Ignition and Combustion Variances of Jet Propellant-8 and Diesel Fuel in Military Diesel Engines

    DTIC Science & Technology

    2008-09-22

    1 ON THE IGNITION AND COMBUSTION VARIANCES OF JET PROPELLANT-8 AND DIESEL FUEL IN MILITARY DIESEL ENGINES Peter Schihl* and Laura Hoogterp... engines for tactical wheeled vehicles due to a variety of reasons related to Environmental Protection Agency (EPA) emission regulations. Such reasons...JP-8. This submission will briefly discuss these practical engine system issues and then present recent applied research that has focused on

  10. Wildfire ignition-distribution modelling: a comparative study in the Huron-Manistee National Forest, Michigan, USA

    Treesearch

    Avi Bar Massada; Alexandra D. Syphard; Susan I. Stewart; Volker C. Radeloff

    2012-01-01

    Wildfire ignition distribution models are powerful tools for predicting the probability of ignitions across broad areas, and identifying their drivers. Several approaches have been used for ignition-distribution modelling, yet the performance of different model types has not been compared. This is unfortunate, given that conceptually similar species-distribution models...

  11. Characterizing dilute combustion instabilities in a multi-cylinder spark-ignited engine using symbolic analysis

    DOE PAGES

    Daw, C. Stuart; Finney, Charles E. A.; Kaul, Brian C.; ...

    2014-12-29

    Spark-ignited internal combustion engines have evolved considerably in recent years in response to increasingly stringent regulations for emissions and fuel-economy. One new advanced engine strategy utilizes high levels of exhaust gas recirculation (EGR) to reduce combustion temperatures, thereby increasing thermodynamic efficiency and reducing nitrogen oxide emissions. While this strategy can be highly effective, it also poses major control and design challenges due to the large combustion oscillations that develop at sufficiently high EGR levels. Previous research has documented that combustion instabilities can propagate between successive engine cycles in individual cylinders via self-generated feedback of reactive species and thermal energy inmore » the retained residual exhaust gases. In this work, we use symbolic analysis to characterize multi-cylinder combustion oscillations in an experimental engine operating with external EGR. At low levels of EGR, intra-cylinder oscillations are clearly visible and appear to be associated with brief, intermittent coupling among cylinders. As EGR is increased further, a point is reached where all four cylinders lock almost completely in phase and alternate simultaneously between two distinct bi-stable combustion states. From a practical perspective, it is important to understand the causes of this phenomenon and develop diagnostics that might be applied to ameliorate its effects. We demonstrate here that two approaches for symbolizing the engine combustion measurements can provide useful probes for characterizing these instabilities.« less

  12. Characterizing dilute combustion instabilities in a multi-cylinder spark-ignited engine using symbolic analysis.

    PubMed

    Daw, C S; Finney, C E A; Kaul, B C; Edwards, K D; Wagner, R M

    2015-02-13

    Spark-ignited internal combustion engines have evolved considerably in recent years in response to increasingly stringent regulations for emissions and fuel economy. One new advanced engine strategy ustilizes high levels of exhaust gas recirculation (EGR) to reduce combustion temperatures, thereby increasing thermodynamic efficiency and reducing nitrogen oxide emissions. While this strategy can be highly effective, it also poses major control and design challenges due to the large combustion oscillations that develop at sufficiently high EGR levels. Previous research has documented that combustion instabilities can propagate between successive engine cycles in individual cylinders via self-generated feedback of reactive species and thermal energy in the retained residual exhaust gases. In this work, we use symbolic analysis to characterize multi-cylinder combustion oscillations in an experimental engine operating with external EGR. At low levels of EGR, intra-cylinder oscillations are clearly visible and appear to be associated with brief, intermittent coupling among cylinders. As EGR is increased further, a point is reached where all four cylinders lock almost completely in phase and alternate simultaneously between two distinct bi-stable combustion states. From a practical perspective, it is important to understand the causes of this phenomenon and develop diagnostics that might be applied to ameliorate its effects. We demonstrate here that two approaches for symbolizing the engine combustion measurements can provide useful probes for characterizing these instabilities. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  13. Characterizing dilute combustion instabilities in a multi-cylinder spark-ignited engine using symbolic analysis

    SciTech Connect

    Daw, C. Stuart; Finney, Charles E. A.; Kaul, Brian C.; Edwards, Kevin Dean; Wagner, Robert M.

    2014-12-29

    Spark-ignited internal combustion engines have evolved considerably in recent years in response to increasingly stringent regulations for emissions and fuel-economy. One new advanced engine strategy utilizes high levels of exhaust gas recirculation (EGR) to reduce combustion temperatures, thereby increasing thermodynamic efficiency and reducing nitrogen oxide emissions. While this strategy can be highly effective, it also poses major control and design challenges due to the large combustion oscillations that develop at sufficiently high EGR levels. Previous research has documented that combustion instabilities can propagate between successive engine cycles in individual cylinders via self-generated feedback of reactive species and thermal energy in the retained residual exhaust gases. In this work, we use symbolic analysis to characterize multi-cylinder combustion oscillations in an experimental engine operating with external EGR. At low levels of EGR, intra-cylinder oscillations are clearly visible and appear to be associated with brief, intermittent coupling among cylinders. As EGR is increased further, a point is reached where all four cylinders lock almost completely in phase and alternate simultaneously between two distinct bi-stable combustion states. From a practical perspective, it is important to understand the causes of this phenomenon and develop diagnostics that might be applied to ameliorate its effects. We demonstrate here that two approaches for symbolizing the engine combustion measurements can provide useful probes for characterizing these instabilities.

  14. Nonlinear torque and air-to-fuel ratio control of spark ignition engines using neuro-sliding mode techniques.

    PubMed

    Huang, Ting; Javaherian, Hossein; Liu, Derong

    2011-06-01

    This paper presents a new approach for the calibration and control of spark ignition engines using a combination of neural networks and sliding mode control technique. Two parallel neural networks are utilized to realize a neuro-sliding mode control (NSLMC) for self-learning control of automotive engines. The equivalent control and the corrective control terms are the outputs of the neural networks. Instead of using error backpropagation algorithm, the network weights of equivalent control are updated using the Levenberg-Marquardt algorithm. Moreover, a new approach is utilized to update the gain of corrective control. Both modifications of the NSLMC are aimed at improving the transient performance and speed of convergence. Using the data from a test vehicle with a V8 engine, we built neural network models for the engine torque (TRQ) and the air-to-fuel ratio (AFR) dynamics and developed NSLMC controllers to achieve tracking control. The goal of TRQ control and AFR control is to track the commanded values under various operating conditions. From simulation studies, the feasibility and efficiency of the approach are illustrated. For both control problems, excellent tracking performance has been achieved.

  15. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    SciTech Connect

    Pratapas, John; Mather, Daniel; Kozlovsky, Anton

    2013-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen’s significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an

  16. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    SciTech Connect

    John Pratapas; Daniel Mather; Anton Kozlovsky

    2007-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen's significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an

  17. Development of Modeling Capabilities for Launch Pad Acoustics and Ignition Transient Environment Prediction

    NASA Technical Reports Server (NTRS)

    West, Jeff; Strutzenberg, Louise L.; Putnam, Gabriel C.; Liever, Peter A.; Williams, Brandon R.

    2012-01-01

    This paper presents development efforts to establish modeling capabilities for launch vehicle liftoff acoustics and ignition transient environment predictions. Peak acoustic loads experienced by the launch vehicle occur during liftoff with strong interaction between the vehicle and the launch facility. Acoustic prediction engineering tools based on empirical models are of limited value in efforts to proactively design and optimize launch vehicles and launch facility configurations for liftoff acoustics. Modeling approaches are needed that capture the important details of the plume flow environment including the ignition transient, identify the noise generation sources, and allow assessment of the effects of launch pad geometric details and acoustic mitigation measures such as water injection. This paper presents a status of the CFD tools developed by the MSFC Fluid Dynamics Branch featuring advanced multi-physics modeling capabilities developed towards this goal. Validation and application examples are presented along with an overview of application in the prediction of liftoff environments and the design of targeted mitigation measures such as launch pad configuration and sound suppression water placement.

  18. A comparative study of diesel ignited methane and propane dual fuel low temperature combustion in a single cylinder research engine

    NASA Astrophysics Data System (ADS)

    Raihan, Mostafa Shameem

    The objective of this thesis is to investigate and compare the performance and emissions characteristics of diesel-ignited methane and diesel-ignited propane dual fuel LTC in a single cylinder research engine (SCRE) at a constant engine load of 5.1 bar net indicated mean effective pressure (IMEP) and at a constant engine speed of 1500 RPM. Percentage of energy substitution of propane or methane (0 - 90 percent), diesel injection timing (SOI: 355 CAD -- 280 CAD), rail pressure (200 bar -- 1300 bar) and boost pressure (1.1 bar -- 1.8 bar) were varied to quantify their impact on engine performance and engine-out ISNOx, ISHC, ISCO, and smoke emissions. Advancing SOI to 310 CAD and beyond yielded simultaneous ISNOx and smoke emissions. A rail pressure of 500 bar was the optimal one for both fueling combinations while increasing boost pressure over 1.2 bar had a very little effect on ISNOx and smoke emissions.

  19. Space-time modelling of lightning-caused ignitions in the Blue Mountains, Oregon

    USGS Publications Warehouse

    Diaz-Avalos, Carlos; Peterson, D.L.; Alvarado, Ernesto; Ferguson, Sue A.; Besag, Julian E.

    2001-01-01

    Generalized linear mixed models (GLMM) were used to study the effect of vegetation cover, elevation, slope, and precipitation on the probability of ignition in the Blue Mountains, Oregon, and to estimate the probability of ignition occurrence at different locations in space and in time. Data on starting location of lightning-caused ignitions in the Blue Mountains between April 1986 and September 1993 constituted the base for the analysis. The study area was divided into a pixela??time array. For each pixela??time location we associated a value of 1 if at least one ignition occurred and 0 otherwise. Covariate information for each pixel was obtained using a geographic information system. The GLMMs were fitted in a Bayesian framework. Higher ignition probabilities were associated with the following cover types: subalpine herbaceous, alpine tundra, lodgepole pine (Pinus contorta Dougl. ex Loud.), whitebark pine (Pinus albicaulis Engelm.), Engelmann spruce (Picea engelmannii Parry ex Engelm.), subalpine fir (Abies lasiocarpa (Hook.) Nutt.), and grand fir (Abies grandis (Dougl.) Lindl.). Within each vegetation type, higher ignition probabilities occurred at lower elevations. Additionally, ignition probabilities are lower in the northern and southern extremes of the Blue Mountains. The GLMM procedure used here is suitable for analysing ignition occurrence in other forested regions where probabilities of ignition are highly variable because of a spatially complex biophysical environment.

  20. T & I--Small Engine Repair, the Ignition System. Kit No. 7. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Underwood, Earl

    An instructor's manual and student activity guide on the ignition system of small engines are provided in this set of prevocational education materials which focuses on the vocational area of trade and industry. (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven vocational offerings:…

  1. 76 FR 25246 - Control of Emissions From New and In-Use Marine Compression-Ignition Engines and Vessels; CFR...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-04

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 1042 Control of Emissions From New and In-Use Marine Compression- Ignition Engines and... of Wednesday, April 13, 2011, make the following correction: Sec. 1042.901 0 On page 20551, in...

  2. 76 FR 26620 - Control of Emissions From New and In-Use Marine Compression-Ignition Engines and Vessels; CFR...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-09

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 1042 Control of Emissions From New and In-Use Marine Compression- Ignition Engines and... issue of Wednesday, May 4, 2011, make the following correction: Sec. 1042.901 On page 25246, in...

  3. 76 FR 20550 - Control of Emissions From New and In-Use Marine Compression-Ignition Engines and Vessels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-13

    ... AGENCY 40 CFR Part 1042 Control of Emissions From New and In-Use Marine Compression- Ignition Engines and... July 1, 2010, on page 240, in Sec. 1042.901, the definition of ``New vessel'' is reinstated to read as follows: Sec. 1042.901 Definitions. * * * * * New vessel means any of the following: (1) A vessel...

  4. 75 FR 37310 - Control of Emissions From New and In-Use Nonroad Compression-Ignition Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-29

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 1039 Control of Emissions From New and In-Use Nonroad Compression- Ignition Engines CFR Correction In Title 40 of the Code of Federal Regulations, Part 1000 to End, revised as of July...

  5. "Simultaneous measurement of flame impingement and piston surface temperatures in an optically accessible spark ignition engine"

    NASA Astrophysics Data System (ADS)

    Ding, Carl-Philipp; Honza, Rene; Böhm, Benjamin; Dreizler, Andreas

    2017-04-01

    This paper shows the results of spatially resolved temperature measurements of the piston surface of an optically accessible direct injection spark ignition engine during flame impingement. High-speed thermographic phosphor thermometry (TPT), using Gd3Ga5O12:Cr,Ce, and planar laser-induced fluorescence of the hydroxyl radical (OH-PLIF) were used to investigate the temperature increase and the time and position of flame impingement at the piston surface. Measurements were conducted at two operating cases and showed heating rates of up to 16,000 K/s. The OH-PLIF measurements were used to localize flame impingement and calculate conditioned statistics of the temperature profiles. The TPT coating was characterized and its influence on the temperature measurements evaluated.

  6. Multi-fuel compression-ignition engine and fuel injection pump therefor

    SciTech Connect

    Pien, P.C.

    1990-06-18

    This patent describes a multi-fuel compression-ignition combustion engine. It includes a first source of primary fuel, a second source of secondary fuel, injection pump means including a body means having a bore therein, plunger means including a body means having a bore therein, plunger means movably mounted within the bore, the plunger means having an end portion defining with a portion of the bore a mixing chamber, first supply means for supplying primary fuel from the first source to the mixing chamber, second supply means for supplying secondary fuel from the second source to the mixing chamber so that the primary and secondary fuels are mixed in the mixing chamber to provide a mixture of the primary and secondary fuels.

  7. Tokamak and RFP ignition requirements

    SciTech Connect

    Werley, K.A.

    1991-01-01

    A plasma model is applied to calculate numerically transport- confinement (n{tau}{sub E}) requirements and steady-state operation tokamak. The CIT tokamak and RFP ignition conditions are examined. Physics differences between RFP and tokamaks, and their consequences for a DT ignition machine, are discussed. The ignition RFP, compared to a tokamak, has many physics advantages, including ohmic heating to ignition (no need for auxiliary heating systems), higher beta, low ignition current, less sensitivity of ignition requirements to impurity effects, no hard disruptions (associated with beta or density limits), and successful operation with high radiation fractions (f{sub RAD} {approximately} 0.95). These physics advantages, coupled with important engineering advantages associated with lower external magnetic fields, larger aspect ratios, and smaller plasma cross sections translate into significant cost reductions for both ignition and power reactor. The primary drawback of the RFP is the uncertainty that the present confinement scaling will extrapolate to reactor regimes. The 4-MA ZTH was expected to extend the n{tau}{sub E} transport scaling data three order of magnitude above ZT-40M results, and if the present scaling held, to achieve a DT-equivalent scientific energy breakeven, Q=1. A basecase RFP ignition point is identified with a plasma current of 8.1 MA and no auxiliary heating. 16 refs., 4 figs., 1 tab.

  8. Cyclic Combustion Variations in Dual Fuel Partially Premixed Pilot-Ignited Natural Gas Engines

    SciTech Connect

    Srinivasan, K. K.; Krishnan, S. R.; Qi, Y.

    2012-05-09

    Dual fuel pilot ignited natural gas engines are identified as an efficient and viable alternative to conventional diesel engines. This paper examines cyclic combustion fluctuations in conventional dual fuel and in dual fuel partially premixed low temperature combustion (LTC). Conventional dual fueling with 95% (energy basis) natural gas (NG) substitution reduces NOx emissions by almost 90%t relative to straight diesel operation; however, this is accompanied by 98% increase in HC emissions, 10 percentage points reduction in fuel conversion efficiency (FCE) and 12 percentage points increase in COVimep. Dual fuel LTC is achieved by injection of a small amount of diesel fuel (2-3 percent on an energy basis) to ignite a premixed natural gas₋air mixture to attain very low NOx emissions (less than 0.2 g/kWh). Cyclic variations in both combustion modes were analyzed by observing the cyclic fluctuations in start of combustion (SOC), peak cylinder pressures (Pmax), combustion phasing (Ca50), and the separation between the diesel injection event and Ca50 (termed "relative combustion phasing" ). For conventional dual fueling, as % NG increases, Pmax decreases, SOC and Ca50 are delayed, and cyclic variations increase. For dual fuel LTC, as diesel injection timing is advanced from 20° to 60° BTDC, the relative combustion phasing is identified as an important combustion parameter along with SoC, Pmax, and CaPmax. For both combustion modes, cyclic variations were characterized by alternating slow and fast burn cycles, especially at high %NG and advanced injection timings. Finally, heat release return maps were analyzed to demonstrate thermal management strategies as an effective tool to mitigate cyclic combustion variations, especially in dual fuel LTC.

  9. Chemical Kinetics of Hydrocarbon Ignition in Practical Combustion Systems

    SciTech Connect

    Westbrook, C.K.

    2000-07-07

    Chemical kinetic factors of hydrocarbon oxidation are examined in a variety of ignition problems. Ignition is related to the presence of a dominant chain branching reaction mechanism that can drive a chemical system to completion in a very short period of time. Ignition in laboratory environments is studied for problems including shock tubes and rapid compression machines. Modeling of the laboratory systems are used to develop kinetic models that can be used to analyze ignition in practical systems. Two major chain branching regimes are identified, one consisting of high temperature ignition with a chain branching reaction mechanism based on the reaction between atomic hydrogen with molecular oxygen, and the second based on an intermediate temperature thermal decomposition of hydrogen peroxide. Kinetic models are then used to describe ignition in practical combustion environments, including detonations and pulse combustors for high temperature ignition, and engine knock and diesel ignition for intermediate temperature ignition. The final example of ignition in a practical environment is homogeneous charge, compression ignition (HCCI) which is shown to be a problem dominated by the kinetics intermediate temperature hydrocarbon ignition. Model results show why high hydrocarbon and CO emissions are inevitable in HCCI combustion. The conclusion of this study is that the kinetics of hydrocarbon ignition are actually quite simple, since only one or two elementary reactions are dominant. However, there are many combustion factors that can influence these two major reactions, and these are the features that vary from one practical system to another.

  10. FUEL EFFECTS ON COMBUSTION WITH EGR DILUTION IN SPARK IGNITED ENGINES

    SciTech Connect

    Szybist, James P

    2016-01-01

    The use of EGR as a diluent allows operation with an overall stoichiometric charge composition, and the addition of cooled EGR results in well-understood thermodynamic benefits for improved fuel consumption. This study investigates the effect of fuel on the combustion and emission response of EGR dilution in spark ignited engines. A 2.0 L GM Ecotec LNF engine equipped with the production side-mounted direct injection (DI) fueling system is used in this study. Ethanol, isooctane and certified gasoline are investigated with EGR from 0% to the EGR dilution tolerance. Constant BMEP at 2000 rpm was operated with varying CA50 from 8 CAD to 16 CAD aTDCf. The results show that ethanol gives the largest EGR tolerance at a given combustion phasing, engine load and speed. The improved EGR dilution tolerance with ethanol is attributed to a faster flame speed, which manifests itself as shorter combustion duration. Data shows that the combustion stability limit occurs at a critical combustion duration that is fuel independent. Due to different flame speeds, this critical combustion duration occurs at different EGR levels for the different fuels.

  11. Characterization and effect of using Mahua oil biodiesel as fuel in compression ignition engine

    NASA Astrophysics Data System (ADS)

    Kapilan, N.; Ashok Babu, T. P.; Reddy, R. P.

    2009-12-01

    There is an increasing interest in India, to search for suitable alternative fuels that are environment friendly. This led to the choice of Mahua Oil (MO) as one of the main alternative fuels to diesel. In this investigation, Mahua Oil Biodiesel (MOB) and its blend with diesel were used as fuel in a single cylinder, direct injection and compression ignition engine. The MOB was prepared from MO by transesterification using methanol and potassium hydroxide. The fuel properties of MOB are close to the diesel and confirm to the ASTM standards. From the engine test analysis, it was observed that the MOB, B5 and B20 blend results in lower CO, HC and smoke emissions as compared to diesel. But the B5 and B20 blends results in higher efficiency as compared to MOB. Hence MOB or blends of MOB and diesel (B5 or B20) can be used as a substitute for diesel in diesel engines used in transportation as well as in the agriculture sector.

  12. A model for assessing ignition, flame spread, and burn hazard potential of a multilayered jacket.

    PubMed

    Ezekoye, Ofodike A; Diller, Kenneth R

    2006-01-01

    An analysis is presented of ignition, flame spread, and skin burn associated with the ignition and burning of a multilayered jacket. The important physical processes can all be detailed based on simple thermophysical modeling. The ignition process associated with proximity to a radiant heat source is analyzed to see how a change in external (outer) fabric could have diminished the likelihood of ignition. Once the composite jacket has been ignited, the flame spread process is responsible for the heat transfer to the skin that causes the burn. We analyze the effects of the jacket innermost material on flame spread and on possible burn damage. We show how available thermophysical property data can be used to estimate the effect of inner layer material on burn event duration. Finally, given best-available data on the heat transfer rates between a burning inner layer and skin, we examine the kinetics of skin burn damage to determine the most likely injury that would result.

  13. Large-Eddy Simulations of Motored Flow and Combustion in a Homogeneous-Charge Spark-Ignition Engine

    NASA Astrophysics Data System (ADS)

    Shekhawat, Yajuvendra Singh

    Cycle-to-cycle variations (CCV) of flow and combustion in internal combustion engines (ICE) limit their fuel efficiency and emissions potential. Large-eddy simulation (LES) is the most practical simulation tool to understand the nature of these CCV. In this research, multi-cycle LES of a two-valve, four-stroke, spark-ignition optical engine has been performed for motored and fired operations. The LES mesh quality is assessed using a length scale resolution parameter and a energy resolution parameter. For the motored operation, two 50-consecutive-cycle LES with different turbulence models (Smagorinsky model and dynamic structure model) are compared with the experiment. The pressure comparison shows that the LES is able to capture the wave-dynamics in the intake and exhaust ports. The LES velocity fields are compared with particle-image velocimetry (PIV) measurements at three cutting planes. Based on the structure and magnitude indices, the dynamic structure model is somewhat better than the Smagorinsky model as far as the ensemble-averaged velocity fields are concerned. The CCV in the velocity fields is assessed by proper-orthogonal decomposition (POD). The POD analysis shows that LES is able to capture the level of CCV seen in the experiment. For the fired operation, two 60-cycle LES with different combustion models (thickened frame model and coherent frame model) are compared with experiment. The in-cylinder pressure and the apparent heat release rate comparison shows higher CCV for LES compared to the experiment, with the thickened frame model showing higher CCV than the coherent frame model. The correlation analysis for the LES using thickened frame model shows that the CCV in combustion/pressure is correlated with: the tumble at the intake valve closing, the resolved and subfilter-scale kinetic energy just before spark time, and the second POD mode (shear flow near spark gap) of the velocity fields just before spark time.

  14. The use of modified tyre derived fuel for compression ignition engines.

    PubMed

    Pilusa, T J

    2017-02-01

    This study investigated physical and chemical modification of tyre-derived fuel oil (TDFO) obtained from pyrolysis of waste tyres and rubber products for application as an alternative fuel for compression ignition engines (CIE's). TDFO collected from a local waste tyre treatment facility was refined via a novel "oxidative gas-phase fractional distillation over 13× molecular sieves" to recover the light to medium fractions of the TDFO while oxidising and capturing some sulphur compounds in a gas phase. This was followed by desulphurization and chemical modification to improve cetane number, kinematic viscosity and fuel stability. The resulting fuel was tested in an ADE407T truck engine to compare its performance with petroleum diesel fuel. It was discovered that gas phase oxidative fractional distillation reduces the low boiling point sulphur compounds in TDFO such as mercaptans. Using petroleum diesel fuel as a reference, it was observed that the produced fuel has a lower cetane number, flash point and viscosity. On storage the fuel tends to form fibrous microstructures as a result of auto-oxidation of asphaltenes present in the fuel. Mixtures of alkyl nitrate, vinyl acetate, methacrylic anhydride, methyl-tert butyl ether, n-hexane and n-heptane were used to chemically modify the fuel in accordance with the minimum fuel specifications as per SANS 342. The engine performance tests results did not show any sign of engine ceasing or knocking effect. The power-torque trend was very consistent and compared well with petroleum diesel fuelled engine. The levels of total sulphur are still considerably high compared to other cleaner fuel alternatives derived from zero sulphur sources.

  15. Potential benefits of oxygen-enriched intake air in a vehicle powered by a spark-ignition engine

    NASA Astrophysics Data System (ADS)

    Ng, H. K.; Sekar, R. R.

    1994-04-01

    A production vehicle powered by a spark-ignition engine (3.1-L Chevrolet Lumina, model year 1990) was tested. The test used oxygen-enriched intake air containing 25 and 28% oxygen by volume to determine (1) if the vehicle would run without difficulties and (2) if emissions benefits would result. Standard Federal Test Procedure (FTP) emissions test cycles were run satisfactorily. Test results of catalytic converter-out emissions (emissions out of the converter) showed that both carbon monoxide and hydrocarbons were reduced significantly in all three phases of the emissions test cycle. Test results of engine-out emissions (emissions straight out of the engine, with the converter removed) showed that carbon monoxide was significantly reduced in the cold phase. All emission test results were compared with those for normal air (21% oxygen). The catalytic converter also had an improved carbon monoxide conversion efficiency under the oxygen-enriched-air conditions. Detailed results of hydrocarbon speciation indicated large reductions in 1,3-butadiene, formaldehyde, acetaldehyde, and benzene from the engine with the oxygen-enriched air. Catalytic converter-out ozone was reduced by 60% with 25%-oxygen-content air. Although NO(x) emissions increased significantly, both for engine-out and catalytic converter-out emissions, we anticipate that they can be ameliorated in the near future with new control technologies. The automotive industry currently is developing exhaust-gas control technologies for an oxidizing environment; these technologies should reduce NO(x) emissions more efficiently in vehicles that use oxygen-enriched intake air. On the basis of estimates made from current data, several production vehicles that had low NO(x) emissions could meet the 2004 Tier 2 emissions standards with 25%-oxygen-content air.

  16. Potential benefits of oxygen-enriched intake air in a vehicle powered by a spark-ignition engine

    SciTech Connect

    Ng, H.K.; Sekar, R.R.

    1994-04-01

    A production vehicle powered by a spark-ignition engine (3.1-L Chevrolet Lumina, model year 1990) was tested. The test used oxygen-enriched intake air containing 25 and 28% oxygen by volume to determine (1) if the vehicle would run without difficulties and (2) if emissions benefits would result. Standard Federal Test Procedure (FTP) emissions test cycles were run satisfactorily. Test results of catalytic converter-out emissions (emissions out of the converter) showed that both carbon monoxide and hydrocarbons were reduced significantly in all three phases of the emissions test cycle. Test results of engine-out emissions (emissions straight out of the engine, with the converter removed) showed that carbon monoxide was significantly reduced in the cold phase. All emission test results were compared with those for normal air (21% oxygen). The catalytic converter also had an improved carbon monoxide conversion efficiency under the oxygen-enriched-air conditions. Detailed results of hydrocarbon speciation indicated large reductions in 1,3-butadiene, formaldehyde, acetaldehyde, and benzene from the engine with the oxygen-enriched air. Catalytic converter-out ozone was reduced by 60% with 25%-oxygen-content air. Although NO{sub x} emissions increased significantly, both for engine-out and catalytic converter-out emissions, we anticipate that they can be ameliorated in the near future with new control technologies. The automotive industry currently is developing exhaust-gas control technologies for an oxidizing environment; these technologies should reduce NO{sub x} emissions more efficiently in vehicles that use oxygen-enriched intake air. On the basis of estimates made from current data, several production vehicles that had low NO{sub x} emissions could meet the 2004 Tier II emissions standards with 25%-oxygen-content air.

  17. Modeling potential structure ignitions from flame radiation exposure with implications for wildland/urban interface fire management

    Treesearch

    Jack D. Cohen; Bret W. Butler

    1998-01-01

    Residential losses associated with wildland fires have become a serious international fire protection problem. The radiant heat flux from burning vegetation adjacent to a structure is a principal ignition factor. A thermal radiation and ignition model estimated structure ignition potential using designated flame characteristics (inferred from various types and...

  18. Experimental studies on the group ignition of a cloud of coal particles: Volume 2, Pyrolysis and ignition modeling. Final report, August 15, 1988--October 15, 1991

    SciTech Connect

    Annamalai, K.; Ryan, W.

    1992-01-01

    The primary objectives of this work are to formulate a model to simulate transient coal pyrolysis, ignition, and combustion of a cloud of coal particles and to compare results of the program with those reported in the literature elsewhere.

  19. Ignition and Growth Modeling of LX-17 Hockey Puck Experiments

    SciTech Connect

    Tarver, C M

    2004-04-19

    Detonating solid plastic bonded explosives (PBX) formulated with the insensitive molecule triaminotrinitrobenzene (TATB) exhibit measurable reaction zone lengths, curved shock fronts, and regions of failing chemical reaction at abrupt changes in the charge geometry. A recent set of ''hockey puck'' experiments measured the breakout times of diverging detonation waves in ambient temperature LX-17 (92.5 % TATB plus 7.5% Kel-F binder) and the breakout times at the lower surfaces of 15 mm thick LX-17 discs placed below the detonator-booster plane. The LX-17 detonation waves in these discs grow outward from the initial wave leaving regions of unreacted or partially reacted TATB in the corners of these charges. This new experimental data is accurately simulated for the first time using the Ignition and Growth reactive flow model for LX-17, which is normalized to a great deal of detonation reaction zone, failure diameter and diverging detonation data. A pressure cubed dependence for the main growth of reaction rate yields excellent agreement with experiment, while a pressure squared rate diverges too quickly and a pressure quadrupled rate diverges too slowly in the LX-17 below the booster equatorial plane.

  20. Ignition and Growth Reactive Flow Model for IMX-101

    SciTech Connect

    Tarver, Craig M.

    2016-02-19

    A set of Ignition and Growth (I&G) reactive flow model parameters is developed for the explosive IMX-101 containing DNAN, NQ, and NTO using the available shock initiation and detonation wave propagation experimental data. The unreacted equation of state for IMX-101 is based on experimental data from gas gun experiments by Furnish et al. and is similar to that of TNT. The product equation of state for IMX-101 is based on CHEETAH chemical equilibrium calculations and cylinder test experimental data. The IMX-101 reaction rate parameters are developed using hydrodynamic reactive flow simulations of several shock initiation and detonation experiments. One set of I&G parameters does a good job of reproducing both shock initiation and detonation experimental data. This is due to the fact that IMX-101 reacts over a relatively small pressure range from about 7 GPa to 20 GPa (C-J pressure). Advanced experiments using embedded gauges and/or laser interferometry could lead to better parameters.

  1. 14 CFR 25.1145 - Ignition switches.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ignition switches. 25.1145 Section 25.1145... switches. (a) Ignition switches must control each engine ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  2. 14 CFR 25.1145 - Ignition switches.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ignition switches. 25.1145 Section 25.1145... switches. (a) Ignition switches must control each engine ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  3. 14 CFR 25.1145 - Ignition switches.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Powerplant Controls and Accessories § 25.1145 Ignition switches. (a) Ignition switches must control each engine ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control. (c...

  4. 14 CFR 25.1145 - Ignition switches.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ignition switches. 25.1145 Section 25.1145... switches. (a) Ignition switches must control each engine ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  5. 14 CFR 25.1145 - Ignition switches.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ignition switches. 25.1145 Section 25.1145... switches. (a) Ignition switches must control each engine ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  6. Detailed Characterization of Particulates Emitted by Pre-Commercial Single-Cylinder Gasoline Compression Ignition Engine

    SciTech Connect

    Zelenyuk, Alla; Reitz, Paul; Stewart, Mark L.; Imre, D.; Loeper, Paul; Adams, Cory; Andrie, Michael; Rothamer, David; Foster, David E.; Narayanaswamy, Kushal; Najt, Paul M.; Solomon, Arun S.

    2014-08-01

    Gasoline Compression Ignition (GCI) engines have the potential to achieve high fuel efficiency and to significantly reduce both NOx and particulate matter (PM) emissions by operating under dilute partially-premixed conditions. This low temperature combustion strategy is dependent upon direct-injection of gasoline during the compression stroke and potentially near top dead center (TDC). The timing and duration of the in-cylinder injections can be tailored based on speed and load to create optimized conditions that result in a stable combustion. We present the results of advanced aerosol analysis methods that have been used for detailed real-time characterization of PM emitted from a single-cylinder GCI engine operated at different speed, load, timing, and number and duration of near-TDC fuel injections. PM characterization included 28 measurements of size and composition of individual particles sampled directly from the exhaust and after mass and/or mobility classification. We use these data to calculate particle effective density, fractal dimension, dynamic shape factors in free-molecular and transition flow regimes, average diameter of primary spherules, number of spherules, and void fraction of soot agglomerates.

  7. Particle emissions, volatility, and toxicity from an ethanol fumigated compression ignition engine.

    PubMed

    Surawski, Nicholas C; Miljevic, Branka; Roberts, Boyd A; Modini, Robin L; Situ, Rong; Brown, Richard J; Bottle, Steven E; Ristovski, Zoran D

    2010-01-01

    Particle emissions, volatility, and the concentration of reactive oxygen species (ROS) were investigated for a pre-Euro I compression ignition engine to study the potential health impacts of employing ethanol fumigation technology. Engine testing was performed in two separate experimental campaigns with most testing performed at intermediate speed with four different load settings and various ethanol substitutions. A scanning mobility particle sizer (SMPS) was used to determine particle size distributions, a volatilization tandem differential mobility analyzer (V-TDMA) was used to explore particle volatility, and a new profluorescent nitroxide probe, BPEAnit, was used to investigate the potential toxicity of particles. The greatest particulate mass reduction was achieved with ethanol fumigation at full load, which contributed to the formation of a nucleation mode. Ethanol fumigation increased the volatility of particles by coating the particles with organic material or by making extra organic material available as an external mixture. In addition, the particle-related ROS concentrations increased with ethanol fumigation and were associated with the formation of a nucleation mode. The smaller particles, the increased volatility, and the increase in potential particle toxicity with ethanol fumigation may provide a substantial barrier for the uptake of fumigation technology using ethanol as a supplementary fuel.

  8. Analysis of Ignition Behavior in a Turbocharged Direct Injection Dual Fuel Engine Using Propane and Methane as Primary Fuels

    SciTech Connect

    Polk, A. C.; Gibson, C. M.; Shoemaker, N. T.; Srinivasan, K. K.; Krishnan, S. R.

    2013-05-24

    This paper presents experimental analyses of the ignition delay (ID) behavior for diesel-ignited propane and diesel-ignited methane dual fuel combustion. Two sets of experiments were performed at a constant speed (1800 rev/min) using a 4-cylinder direct injection diesel engine with the stock ECU and a wastegated turbocharger. First, the effects of fuel-air equivalence ratios (© pilot ¼ 0.2-0.6 and © overall ¼ 0.2-0.9) on IDs were quantified. Second, the effects of gaseous fuel percent energy substitution (PES) and brake mean effective pressure (BMEP) (from 2.5 to 10 bar) on IDs were investigated. With constant © pilot (> 0.5), increasing © overall with propane initially decreased ID but eventually led to premature propane autoignition; however, the corresponding effects with methane were relatively minor. Cyclic variations in the start of combustion (SOC) increased with increasing © overall (at constant © pilot), more significantly for propane than for methane. With increasing PES at constant BMEP, the ID showed a nonlinear (initially increasing and later decreasing) trend at low BMEPs for propane but a linearly decreasing trend at high BMEPs. For methane, increasing PES only increased IDs at all BMEPs. At low BMEPs, increasing PES led to significantly higher cyclic SOC variations and SOC advancement for both propane and methane. Finally, the engine ignition delay (EID) was also shown to be a useful metric to understand the influence of ID on dual fuel combustion.

  9. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2002-01-01

    In the apparatus of the invention, a first excitation laser or other excitation light source capable of producing alternating beams of light having different wavelengths is used in tandem with one or more ignitor lasers to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using the single remote excitation light source for pumping one or more small lasers located proximate to one or more fuel combustion zones with alternating wavelengths of light.

  10. An analytical investigation of NO sub x control techniques for methanol fueled spark ignition engines

    NASA Technical Reports Server (NTRS)

    Browning, L. H.; Argenbright, L. A.

    1983-01-01

    A thermokinetic SI engine simulation was used to study the effects of simple nitrogen oxide control techniques on performance and emissions of a methanol fueled engine. As part of this simulation, a ring crevice storage model was formulated to predict UBF emissions. The study included spark retard, two methods of compression ratio increase and EGR. The study concludes that use of EGR in high turbulence, high compression engines will both maximize power and thermal efficiency while minimizing harmful exhaust pollutants.

  11. Reactive nanolaminate pulsed-laser ignition mechanism: Modeling and experimental evidence of diffusion limited reactions

    NASA Astrophysics Data System (ADS)

    Yarrington, C. D.; Abere, M. J.; Adams, D. P.; Hobbs, M. L.

    2017-04-01

    Al/Pt nanolaminates with a bilayer thickness (tb, width of an Al/Pt pair-layer) of 164 nm were irradiated with single laser pulses with durations of 10 ms and 0.5 ms at 189 W/cm2 and 1189 W/cm2, respectively. The time to ignition was measured for each pulse, and shorter ignition times were observed for the higher power/shorter pulse width. Videographic images of the irradiated area shortly after ignition show a non-uniform radial brightness for the longer pulse, while the shorter pulse shows uniform brightness. A diffusion-limited single step reaction mechanism was implemented in a finite element package to model the progress from reactants to products at both pulse widths. The model captures well both the observed ignition delay and qualitative observations regarding the non-uniform radial temperature.

  12. Reactive nanolaminate pulsed-laser ignition mechanism: Modeling and experimental evidence of diffusion limited reactions

    DOE PAGES

    Yarrington, C. D.; Abere, M. J.; Adams, D. P.; ...

    2017-04-03

    We irradiated Al/Pt nanolaminates with a bilayer thickness (tb, width of an Al/Pt pair-layer) of 164 nm with single laser pulses with durations of 10 ms and 0.5 ms at 189 W/cm2 and 1189 W/cm2, respectively. The time to ignition was measured for each pulse, and shorter ignition times were observed for the higher power/shorter pulse width. While the shorter pulse shows uniform brightness, videographic images of the irradiated area shortly after ignition show a non-uniform radial brightness for the longer pulse. A diffusion-limited single step reaction mechanism was implemented in a finite element package to model the progress frommore » reactants to products at both pulse widths. Finally, the model captures well both the observed ignition delay and qualitative observations regarding the non-uniform radial temperature.« less

  13. A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

    DOE PAGES

    Dempsey, Adam B.; Curran, Scott J.; Wagner, Robert M.

    2016-01-14

    Many research studies have shown that low temperature combustion in compression ignition engines has the ability to yield ultra-low NOx and soot emissions while maintaining high thermal efficiency. To achieve low temperature combustion, sufficient mixing time between the fuel and air in a globally dilute environment is required, thereby avoiding fuel-rich regions and reducing peak combustion temperatures, which significantly reduces soot and NOx formation, respectively. It has been demonstrated that achieving low temperature combustion with diesel fuel over a wide range of conditions is difficult because of its properties, namely, low volatility and high chemical reactivity. On the contrary, gasolinemore » has a high volatility and low chemical reactivity, meaning it is easier to achieve the amount of premixing time required prior to autoignition to achieve low temperature combustion. In order to achieve low temperature combustion while meeting other constraints, such as low pressure rise rates and maintaining control over the timing of combustion, in-cylinder fuel stratification has been widely investigated for gasoline low temperature combustion engines. The level of fuel stratification is, in reality, a continuum ranging from fully premixed (i.e. homogeneous charge of fuel and air) to heavily stratified, heterogeneous operation, such as diesel combustion. However, to illustrate the impact of fuel stratification on gasoline compression ignition, the authors have identified three representative operating strategies: partial, moderate, and heavy fuel stratification. Thus, this article provides an overview and perspective of the current research efforts to develop engine operating strategies for achieving gasoline low temperature combustion in a compression ignition engine via fuel stratification. In this paper, computational fluid dynamics modeling of the in-cylinder processes during the closed valve portion of the cycle was used to illustrate the opportunities

  14. A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

    SciTech Connect

    Dempsey, Adam B.; Curran, Scott J.; Wagner, Robert M.

    2016-01-14

    Many research studies have shown that low temperature combustion in compression ignition engines has the ability to yield ultra-low NOx and soot emissions while maintaining high thermal efficiency. To achieve low temperature combustion, sufficient mixing time between the fuel and air in a globally dilute environment is required, thereby avoiding fuel-rich regions and reducing peak combustion temperatures, which significantly reduces soot and NOx formation, respectively. It has been demonstrated that achieving low temperature combustion with diesel fuel over a wide range of conditions is difficult because of its properties, namely, low volatility and high chemical reactivity. On the contrary, gasoline has a high volatility and low chemical reactivity, meaning it is easier to achieve the amount of premixing time required prior to autoignition to achieve low temperature combustion. In order to achieve low temperature combustion while meeting other constraints, such as low pressure rise rates and maintaining control over the timing of combustion, in-cylinder fuel stratification has been widely investigated for gasoline low temperature combustion engines. The level of fuel stratification is, in reality, a continuum ranging from fully premixed (i.e. homogeneous charge of fuel and air) to heavily stratified, heterogeneous operation, such as diesel combustion. However, to illustrate the impact of fuel stratification on gasoline compression ignition, the authors have identified three representative operating strategies: partial, moderate, and heavy fuel stratification. Thus, this article provides an overview and perspective of the current research efforts to develop engine operating strategies for achieving gasoline low temperature combustion in a compression ignition engine via fuel stratification. In this paper, computational fluid dynamics modeling of the in-cylinder processes during the closed valve portion of the cycle was used to illustrate the opportunities and

  15. Signal Analysis of Automotive Engine Spark Ignition System using Case-Based Reasoning (CBR) and Case-based Maintenance (CBM)

    SciTech Connect

    Huang, H.; Vong, C. M.; Wong, P. K.

    2010-05-21

    With the development of modern technology, modern vehicles adopt electronic control system for injection and ignition. In traditional way, whenever there is any malfunctioning in an automotive engine, an automotive mechanic usually performs a diagnosis in the ignition system of the engine to check any exceptional symptoms. In this paper, we present a case-based reasoning (CBR) approach to help solve human diagnosis problem. Nevertheless, one drawback of CBR system is that the case library will be expanded gradually after repeatedly running the system, which may cause inaccuracy and longer time for the CBR retrieval. To tackle this problem, case-based maintenance (CBM) framework is employed so that the case library of the CBR system will be compressed by clustering to produce a set of representative cases. As a result, the performance (in retrieval accuracy and time) of the whole CBR system can be improved.

  16. Modelling Testing and Design Considerations of a GOX-GCH4 Igniter for a Hyprob-SSBB Single Igniter Thrust Chamber

    NASA Astrophysics Data System (ADS)

    Battista, F.

    This paper discusses design, test results and preliminary numerical rebuilding of the GOX-GCH4 igniter for a subscale experimental "breadboard" (SSBB) LOX/Methane rocket engine in the framework of the HYPROB-BREAD project. The igniter architecture takes into account different literature efforts and has been selected with the objective of achieving good performance with low cost. CFD, FEM and system simulations have been performed in order to demonstrate the validity of the design. The main results from the first experimental campaign as well as a preliminary numerical rebuilding analysis are shown.

  17. Modeling LX-17 Detonation Growth and Decay Using the Ignition and Growth Model

    NASA Astrophysics Data System (ADS)

    Tarver, Craig M.; Chidester, Steven K.

    2009-12-01

    The previously established Ignition and Growth reactive flow model for the detonating triaminotrinitrobenzene (TATB) based plastic bonded explosive LX-17 is applied to recent experimental detonation propagation/failure experiments using unconfined, Lucite confined, and copper confined cylinders. The model also simulates two corner turning experiments in which steel and Lucite act as boundary materials. Finally, the model is used to calculate a one-inch diameter "Hockey Puck" test in which the booster explosive is HMX-based rather than TATB-based. Since the LX-17 Ignition and Growth model parameters are normalized to a great deal of one-, two- and three-dimensional detonation propagation data, they accurately predict all of this new experimental detonation velocity and arrival time data.

  18. Selection Criteria and Screening of Potential Biomass-Derived Streams as Fuel Blendstocks for Advanced Spark-Ignition Engines

    DOE PAGES

    McCormick, Robert L.; Fioroni, Gina; Fouts, Lisa; ...

    2017-03-28

    Here, we describe a study to identify potential biofuels that enable advanced spark ignition (SI) engine efficiency strategies to be pursued more aggressively. A list of potential biomass-derived blendstocks was developed. An online database of properties and characteristics of these bioblendstocks was created and populated. Fuel properties were determined by measurement, model prediction, or literature review. Screening criteria were developed to determine if a bioblendstock met the requirements for advanced SI engines. Criteria included melting point (or cloud point) < -10 degrees C and boiling point (or T90) <165 degrees C. Compounds insoluble or poorly soluble in hydrocarbon were eliminatedmore » from consideration, as were those known to cause corrosion (carboxylic acids or high acid number mixtures) and those with hazard classification as known or suspected carcinogens or reproductive toxins. Compounds predicted to be less anaerobically biodegradable than methyl-tert-butyl ether with water solubility greater than 10,000 mg/L were also eliminated. A minimum Research octane number (RON) of 98 was applied. These criteria produced a list of 40 bioblendstocks with promising properties. Additional property data, including Motor octane number (MON), heat of vaporization, and lower heating value, were acquired for these bioblendstocks. A subset of the bioblendstocks representing all functional groups were blended into gasoline or a gasoline surrogate to measure their effect on vapor pressure, distillation curve, oxidation stability, RON, and MON. For blending into a conventional or reformulated blendstock for E10 blending, ethanol, 2-butanol, isobutanol, and diisobutylene have the most desirable properties for blending of a high-octane advanced SI engine fuel.« less

  19. Performance analysis of exhaust heat recovery using organic Rankine cycle in a passenger car with a compression ignition engine

    NASA Astrophysics Data System (ADS)

    Ghilvacs, M.; Prisecaru, T.; Pop, H.; Apostol, V.; Prisecaru, M.; Pop, E.; Popescu, Gh; Ciobanu, C.; Mohanad, A.; Alexandru, A.

    2016-08-01

    Compression ignition engines transform approximately 40% of the fuel energy into power available at the crankshaft, while the rest part of the fuel energy is lost as coolant, exhaust gases and other waste heat. An organic Rankine cycle (ORC) can be used to recover this waste heat. In this paper, the characteristics of a system combining a compression ignition engine with an ORC which recover the waste heat from the exhaust gases are analyzed. The performance map of the diesel engine is measured on an engine test bench and the heat quantities wasted by the exhaust gases are calculated over the engine's entire operating region. Based on this data, the working parameters of ORC are defined, and the performance of a combined engine-ORC system is evaluated across this entire region. The results show that the net power of ORC is 6.304kW at rated power point and a maximum of 10% reduction in brake specific fuel consumption can be achieved.

  20. 14 CFR 33.37 - Ignition system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ignition system. 33.37 Section 33.37... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.37 Ignition system. Each spark ignition engine must have a dual ignition system with at least two spark plugs for each...

  1. 14 CFR 33.37 - Ignition system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ignition system. 33.37 Section 33.37... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.37 Ignition system. Each spark ignition engine must have a dual ignition system with at least two spark plugs for each...

  2. 14 CFR 33.37 - Ignition system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.37 Ignition system. Each spark ignition engine must have a dual ignition system with at least two spark plugs for each cylinder and two separate electric circuits with separate sources of electrical energy, or have an ignition...

  3. 14 CFR 33.37 - Ignition system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.37 Ignition system. Each spark ignition engine must have a dual ignition system with at least two spark plugs for each cylinder and two separate electric circuits with separate sources of electrical energy, or have an ignition...

  4. 14 CFR 33.37 - Ignition system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.37 Ignition system. Each spark ignition engine must have a dual ignition system with at least two spark plugs for each cylinder and two separate electric circuits with separate sources of electrical energy, or have an ignition...

  5. Ethanol Blends and Engine Operating Strategy Effects on Light-Duty Spark-Ignition Engine Particle Emissions

    SciTech Connect

    Szybist, James P; Youngquist, Adam D; Barone, Teresa L; Storey, John Morse; Moore, Wayne; Foster, Matthew; Confer, Keith

    2011-01-01

    Spark ignition (SI) engines with direct injection (DI) fueling can improve fuel economy and vehicle power beyond that of port fuel injection (PFI). Despite this distinct advantage, DI fueling often increases particle emissions such that SI exhaust may be subject to future particle emissions regulations. Challenges in controlling particle emissions arise as engines encounter varied fuel composition such as intermediate ethanol blends. Furthermore, modern engines are operated using unconventional breathing strategies with advanced cam-based variable valve actuation systems. In this study, we investigate particle emissions from a multi-cylinder DI engine operated with three different breathing strategies, fueling strategies and fuels. The breathing strategies are conventional throttled operation, early intake valve closing (EIVC) and late intake valve closing (LIVC); the fueling strategies are single injection DI (sDI), multi-injection DI (mDI), and PFI; and the fuels are emissions certification gasoline, E20 and E85. The results indicate the dominant factor influencing particle number concentration emissions for the sDI and mDI strategies is the fuel injection timing. Overly advanced injection timing results in particle formation due to fuel spray impingement on the piston, and overly retarded injection timing results in particle formation due to poor fuel and air mixing. In addition, fuel type has a significant effect on particle emissions for the DI fueling strategies. Gasoline and E20 fuels generate comparable levels of particle emissions, but E85 produces dramatically lower particle number concentration. The particle emissions for E85 are near the detection limit for the FSN instrument, and particle number emissions are one to two orders of magnitude lower for E85 relative to gasoline and E20. We found PFI fueling produces very low levels of particle emissions under all conditions and is much less sensitive to engine breathing strategy and fuel type than the DI

  6. The effectiveness of a double-stem injection valve in controlling combustion in a compression-ignition engine

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Whitney, E G

    1931-01-01

    An investigation was made to determine to what extent the rates of combustion in a compression-ignition engine can be controlled by varying the rates of fuel injection. The tests showed that the double-stem valve operated satisfactorily under all normal injection conditions; the rate of injection has a definite effect on the rate of combustion; the engine performance with the double-stem valve was inferior to that obtained with a single-stem valve; and the control of injection rates permitted by an injection valve of two stages of discharge is not sufficient to effect the desired rates of combustion.

  7. Computer modeling of cool flames and ignition of acetaldehyde

    SciTech Connect

    Cavanagh, J.; Cox, R.A. ); Olson, G. )

    1990-10-01

    A detailed mechanism for the oxidation of acetaldehyde at temperatures between 500-1000 K has been assembled using 77 elementary reactions involving 32 reactant, product, and intermediate species. Rate coefficients were taken from recent critical evaluations of experimental data. Where experimental measurements were not available, the rate parameters were estimated from the body of currently available kinetics information. The mechanism was shown to predict correctly the rates and products observed in CH{sub 3}CHO oxidation studies in a low-pressure in a stirred flow reactor and at high pressure in a rapid compression machine. The oscillatory phenomena in the flow system and the two-stage ignition observed at high pressure were satisfactorily described by the mechanism. It is shown that cool flames are caused by degenerate branching mainly by peracetic acid and that hydrogen peroxide promotes hot ignition.

  8. Ignition experiments and models of a plastic bonded explosive (PBX 9502).

    PubMed

    Hobbs, M L; Kaneshige, M J

    2014-03-28

    Ignition experiments from various sources, including our own laboratory, have been used to develop a simple four-step, pressure-dependent ignition model for PBX 9502, which is composed of 95% by mass triaminotrinitrobenzene (TATB) and a 5% by mass chlorotrifluoroethylene/vinylidine fluoride binder. The four-steps include drying, mono-furazan formation, and decomposition of mono-furazan and TATB into equilibrium products. Our experiments were both sealed and vented and included various ullage percentages ranging from 18% to 75% of unfilled confinement volume. Our sample densities ranged from 38% of the theoretical maximum density (TMD) to 98% TMD. We observed a decrease in ignition times with the higher density samples, an increase in ignition times with increased venting, and an increase in ignition times with increased ullage. From our experiments, we conclude that decomposition of PBX 9502 is pressure dependent, open pore decomposition occurs in low-density experiments, and that closed pore decomposition occurs when the samples are pressed to near full density. In some of our confined high-density experiments we have observed for the first time, multiple temperature excursions prior to ignition caused by internal pressure generation.

  9. Ignition experiments and models of a plastic bonded explosive (PBX 9502)

    NASA Astrophysics Data System (ADS)

    Hobbs, M. L.; Kaneshige, M. J.

    2014-03-01

    Ignition experiments from various sources, including our own laboratory, have been used to develop a simple four-step, pressure-dependent ignition model for PBX 9502, which is composed of 95% by mass triaminotrinitrobenzene (TATB) and a 5% by mass chlorotrifluoroethylene/vinylidine fluoride binder. The four-steps include drying, mono-furazan formation, and decomposition of mono-furazan and TATB into equilibrium products. Our experiments were both sealed and vented and included various ullage percentages ranging from 18% to 75% of unfilled confinement volume. Our sample densities ranged from 38% of the theoretical maximum density (TMD) to 98% TMD. We observed a decrease in ignition times with the higher density samples, an increase in ignition times with increased venting, and an increase in ignition times with increased ullage. From our experiments, we conclude that decomposition of PBX 9502 is pressure dependent, open pore decomposition occurs in low-density experiments, and that closed pore decomposition occurs when the samples are pressed to near full density. In some of our confined high-density experiments we have observed for the first time, multiple temperature excursions prior to ignition caused by internal pressure generation.

  10. Advanced ignition and propulsion technology program

    SciTech Connect

    Oldenborg, R.; Early, J.; Lester, C.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Reliable engine re-ignition plays a crucial role in enabling commercial and military aircraft to fly safely at high altitudes. This project addressed research elements critical to the optimization of laser-based igniter. The effort initially involved a collaborative research and development agreement with B.F. Goodrich Aerospace and Laser Fare, Inc. The work involved integrated experiments with theoretical modeling to provide a basic understanding of the chemistry and physics controlling the laser-induced ignition of fuel aerosols produced by turbojet engine injectors. In addition, the authors defined advanced laser igniter configurations that minimize laser packaging size, weight, complexity and power consumption. These innovative ignition concepts were shown to reliably ignite jet fuel aerosols over a broad range of fuel/air mixture and a t fuel temperatures as low as -40 deg F. The demonstrated fuel ignition performance was highly superior to that obtained by the state-of-the-art, laser-spark ignition method utilizing comparable laser energy. The authors also developed a laser-based method that effectively removes optically opaque deposits of fuel hydrocarbon combustion residues from laser window surfaces. Seven patents have been either issued or are pending that resulted from the technology developments within this project.

  11. A multi-step reaction model for ignition of fully-dense Al-CuO nanocomposite powders

    NASA Astrophysics Data System (ADS)

    Stamatis, D.; Ermoline, A.; Dreizin, E. L.

    2012-12-01

    A multi-step reaction model is developed to describe heterogeneous processes occurring upon heating of an Al-CuO nanocomposite material prepared by arrested reactive milling. The reaction model couples a previously derived Cabrera-Mott oxidation mechanism describing initial, low temperature processes and an aluminium oxidation model including formation of different alumina polymorphs at increased film thicknesses and higher temperatures. The reaction model is tuned using traces measured by differential scanning calorimetry. Ignition is studied for thin powder layers and individual particles using respectively the heated filament (heating rates of 103-104 K s-1) and laser ignition (heating rate ∼106 K s-1) experiments. The developed heterogeneous reaction model predicts a sharp temperature increase, which can be associated with ignition when the laser power approaches the experimental ignition threshold. In experiments, particles ignited by the laser beam are observed to explode, indicating a substantial gas release accompanying ignition. For the heated filament experiments, the model predicts exothermic reactions at the temperatures, at which ignition is observed experimentally; however, strong thermal contact between the metal filament and powder prevents the model from predicting the thermal runaway. It is suggested that oxygen gas release from decomposing CuO, as observed from particles exploding upon ignition in the laser beam, disrupts the thermal contact of the powder and filament; this phenomenon must be included in the filament ignition model to enable prediction of the temperature runaway.

  12. Integration of Microwave Plasma Ignition Into a Multi-Fuel Engine

    DTIC Science & Technology

    2008-10-01

    electronics control, this type of ignition system can easily surpass conventional spark ignition performance and capabilities. Continued work would seek...plasma source as a spark plug replacement. The QWCCR is a highly efficient impedance transformation device that can step up the electrical potential...can be larger than a conventional spark plug spark, thus reducing the thermal point loading that results from a spark gap. Additionally, the nature of

  13. 14 CFR 29.1145 - Ignition switches.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ignition switches. 29.1145 Section 29.1145... switches. (a) Ignition switches must control each ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  14. 14 CFR 29.1145 - Ignition switches.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ignition switches. 29.1145 Section 29.1145... switches. (a) Ignition switches must control each ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  15. 14 CFR 29.1145 - Ignition switches.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ignition switches. 29.1145 Section 29.1145... switches. (a) Ignition switches must control each ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  16. 14 CFR 29.1145 - Ignition switches.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ignition switches. 29.1145 Section 29.1145... switches. (a) Ignition switches must control each ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  17. 14 CFR 29.1145 - Ignition switches.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ignition switches. 29.1145 Section 29.1145... switches. (a) Ignition switches must control each ignition circuit on each engine. (b) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control....

  18. Identification of Knock in NACA High-Speed Photographs of Combustion in a Spark-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Miller, Cearcy D; Olsen, H Lowell

    1943-01-01

    Report presents the results of a study of combustion in a spark-ignition engine given in NACA Technical Reports 704 and 727. The present investigation was made with the NACA high-speed motion-picture camera, operating at 40,000 photographs a second, and with a cathode-ray oscillograph operating on a piezoelectric pick-up in the combustion chamber. Photographs are presented showing that the origin of knock is not necessarily in the end gas. The data obtained indicates that knock takes place only in a part of the cylinder charge which has been previously ignited either by autoignition or by the passage of the flame fronts but which has not burned to completion. Mottled regions in the high-speed Schlieren photographs are demonstrated to represent combustion regions.

  19. Effect of NLTE Emissivity Models on NIF Ignition Hohlraum Power Requirements

    SciTech Connect

    Suter, L.; Rosen, M.; Springer, P.; Haan, S.; Hansen, S.

    2009-09-10

    NLTE atomic physics model can significantly affect the power requirements and plasma conditions in ignition hohlraums. This is because the emissivity is a significant factor in determining the time dependent coronal temperature of the hot blow-off plasma filling ignition hohlraums, which, in turn, determines the total energy stored in that coronal plasma at any instant. Here we present best estimates of NLTE emissivity using the SCRAM model, including the range of uncertainty, and compare them with the emissivity of the model used to design NIF ignition hohlraums and set the NIF pulse shape, XSN NLTE. We then present pulse shapes derived from hohlraum simulations using an atomic physics model that approximates the SCRAM emissivities. We discuss the differences in coronal energetics and show how this affects the pulse shape and, in particular, the peak power requirement.

  20. Liquid Oxygen Rotating Friction Ignition Testing of Aluminum and Titanium with Monel and Inconel for Rocket Engine Propulsion System Contamination Investigation

    NASA Technical Reports Server (NTRS)

    Peralta, S.; Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    Metallic contaminant was found in the liquid oxygen (LOX) pre-valve screen of the shuttle main engine propulsion system on two orbiter vehicles. To investigate the potential for an ignition, NASA Johnson Space Center White Sands Test Facility performed (modified) rotating friction ignition testing in LOX. This testing simulated a contaminant particle in the low-pressure oxygen turbo pump (LPOTP) and the high-pressure oxygen turbo pump (HPOTP) of the shuttle main propulsion system. Monel(R) K-500 and Inconel(R) 718 samples represented the LPOTP and HPOTP materials. Aluminum foil tape and titanium foil represented the contaminant particles. In both the Monel(R) and Inconel(R) material configurations, the aluminum foil tape samples did not ignite after 30 s of rubbing. In contrast, all of the titanium foil samples ignited regardless of the rubbing duration or material configuration. However, the titanium foil ignitions did not propagate to the Monel and Inconel materials.

  1. Radiation hydrodynamics modeling of the highest compression inertial confinement fusion ignition experiment from the National Ignition Campaign

    NASA Astrophysics Data System (ADS)

    Clark, D. S.; Marinak, M. M.; Weber, C. R.; Eder, D. C.; Haan, S. W.; Hammel, B. A.; Hinkel, D. E.; Jones, O. S.; Milovich, J. L.; Patel, P. K.; Robey, H. F.; Salmonson, J. D.; Sepke, S. M.; Thomas, C. A.

    2015-02-01

    The recently completed National Ignition Campaign (NIC) on the National Ignition Facility (NIF) showed significant discrepancies between post-shot simulations of implosion performance and experimentally measured performance, particularly in thermonuclear yield. This discrepancy between simulation and observation persisted despite concerted efforts to include all of the known sources of performance degradation within a reasonable two-dimensional (2-D), and even three-dimensional (3-D), simulation model, e.g., using measured surface imperfections and radiation drives adjusted to reproduce observed implosion trajectories [Clark et al., Phys. Plasmas 20, 056318 (2013)]. Since the completion of the NIC, several effects have been identified that could explain these discrepancies and that were omitted in previous simulations. In particular, there is now clear evidence for larger than anticipated long-wavelength radiation drive asymmetries and a larger than expected perturbation seeded by the capsule support tent. This paper describes an updated suite of one-dimensional (1-D), 2-D, and 3-D simulations that include the current best understanding of these effects identified since the NIC, as applied to a specific NIC shot. The relative importance of each effect on the experimental observables is compared. In combination, these effects reduce the simulated-to-measured yield ratio from 125:1 in 1-D to 1.5:1 in 3-D, as compared to 15:1 in the best 2-D simulations published previously. While the agreement with the experimental data remains imperfect, the comparison to the data is significantly improved and suggests that the largest sources for the previous discrepancies between simulation and experiment are now being included.

  2. Physicochemical characterization of particulate emissions from a compression ignition engine: the influence of biodiesel feedstock.

    PubMed

    Surawski, N C; Miljevic, B; Ayoko, G A; Elbagir, S; Stevanovic, S; Fairfull-Smith, K E; Bottle, S E; Ristovski, Z D

    2011-12-15

    This study undertook a physicochemical characterization of particle emissions from a single compression ignition engine operated at one test mode with 3 biodiesel fuels made from 3 different feedstocks (i.e., soy, tallow, and canola) at 4 different blend percentages (20%, 40%, 60%, and 80%) to gain insights into their particle-related health effects. Particle physical properties were inferred by measuring particle number size distributions both with and without heating within a thermodenuder (TD) and also by measuring particulate matter (PM) emission factors with an aerodynamic diameter less than 10 μm (PM(10)). The chemical properties of particulates were investigated by measuring particle and vapor phase Polycyclic Aromatic Hydrocarbons (PAHs) and also Reactive Oxygen Species (ROS) concentrations. The particle number size distributions showed strong dependency on feedstock and blend percentage with some fuel types showing increased particle number emissions, while others showed particle number reductions. In addition, the median particle diameter decreased as the blend percentage was increased. Particle and vapor phase PAHs were generally reduced with biodiesel, with the results being relatively independent of the blend percentage. The ROS concentrations increased monotonically with biodiesel blend percentage but did not exhibit strong feedstock variability. Furthermore, the ROS concentrations correlated quite well with the organic volume percentage of particles - a quantity which increased with increasing blend percentage. At higher blend percentages, the particle surface area was significantly reduced, but the particles were internally mixed with a greater organic volume percentage (containing ROS) which has implications for using surface area as a regulatory metric for diesel particulate matter (DPM) emissions.

  3. Multifractal and statistical analyses of heat release fluctuations in a spark ignition engine.

    PubMed

    Sen, Asok K; Litak, Grzegorz; Kaminski, Tomasz; Wendeker, Mirosław

    2008-09-01

    Using multifractal and statistical analyses, we have investigated the complex dynamics of cycle-to-cycle heat release variations in a spark ignition engine. Three different values of the spark advance angle (Delta beta) are examined. The multifractal complexity is characterized by the singularity spectrum of the heat release time series in terms of the Holder exponent. The broadness of the singularity spectrum gives a measure of the degree of mutifractality or complexity of the time series. The broader the spectrum, the richer and more complex is the structure with a higher degree of multifractality. Using this broadness measure, the complexity in heat release variations is compared for the three spark advance angles (SAAs). Our results reveal that the heat release data are most complex for Delta beta=30 degrees followed in order by Delta beta=15 degrees and 5 degrees. In other words, the complexity increases with increasing SAA. In addition, we found that for all the SAAs considered, the heat release fluctuations behave like an antipersistent or a negatively correlated process, becoming more antipersistent with decreasing SAA. We have also performed a statistical analysis of the heat release variations by calculating the kurtosis of their probability density functions (pdfs). It is found that for the smallest SAA considered, Delta beta=5 degrees, the pdf is nearly Gaussian with a kurtosis of 3.42. As the value of the SAA increases, the pdf deviates from a Gaussian distribution and tends to be more peaked with larger values of kurtosis. In particular, the kurtosis has values of 3.94 and 6.69, for Delta beta=15 degrees and 30 degrees, respectively. A non-Gaussian density function with kurtosis in excess of 3 is indicative of intermittency. A larger value of kurtosis implies a higher degree of intermittency. (c) 2008 American Institute of Physics.

  4. Thermal Ignition

    NASA Astrophysics Data System (ADS)

    Boettcher, Philipp Andreas

    Accidental ignition of flammable gases is a critical safety concern in many industrial applications. Particularly in the aviation industry, the main areas of concern on an aircraft are the fuel tank and adjoining regions, where spilled fuel has a high likelihood of creating a flammable mixture. To this end, a fundamental understanding of the ignition phenomenon is necessary in order to develop more accurate test methods and standards as a means of designing safer air vehicles. The focus of this work is thermal ignition, particularly auto-ignition with emphasis on the effect of heating rate, hot surface ignition and flame propagation, and puffing flames. Combustion of hydrocarbon fuels is traditionally separated into slow reaction, cool flame, and ignition regimes based on pressure and temperature. Standard tests, such as the ASTM E659, are used to determine the lowest temperature required to ignite a specific fuel mixed with air at atmospheric pressure. It is expected that the initial pressure and the rate at which the mixture is heated also influences the limiting temperature and the type of combustion. This study investigates the effect of heating rate, between 4 and 15 K/min, and initial pressure, in the range of 25 to 100 kPa, on ignition of n-hexane air mixtures. Mixtures with equivalence ratio ranging from 0.6 to 1.2 were investigated. The problem is also modeled computationally using an extension of Semenov's classical auto-ignition theory with a detailed chemical mechanism. Experiments and simulations both show that in the same reactor either a slow reaction or an ignition event can take place depending on the heating rate. Analysis of the detailed chemistry demonstrates that a mixture which approaches the ignition region slowly undergoes a significant modification of its composition. This change in composition induces a progressive shift of the explosion limit until the mixture is no longer flammable. A mixture that approaches the ignition region

  5. Report from the Integrated Modeling Panel at the Workshop on the Science of Ignition on NIF

    SciTech Connect

    Marinak, M; Lamb, D

    2012-07-03

    This section deals with multiphysics radiation hydrodynamics codes used to design and simulate targets in the ignition campaign. These topics encompass all the physical processes they model, and include consideration of any approximations necessary due to finite computer resources. The section focuses on what developments would have the highest impact on reducing uncertainties in modeling most relevant to experimental observations. It considers how the ICF codes should be employed in the ignition campaign. This includes a consideration of how the experiments can be best structured to test the physical models the codes employ.

  6. Extending lean operating limit and reducing emissions of methane spark-ignited engines using a microwave-assisted spark plug

    DOE PAGES

    Rapp, Vi H.; DeFilippo, Anthony; Saxena, Samveg; ...

    2012-01-01

    Amore » microwave-assisted spark plug was used to extend the lean operating limit (lean limit) and reduce emissions of an engine burning methane-air. In-cylinder pressure data were collected at normalized air-fuel ratios of λ = 1.46, λ = 1.51, λ = 1.57, λ = 1.68, and λ = 1.75. For each λ, microwave energy (power supplied to the magnetron per engine cycle) was varied from 0 mJ (spark discharge alone) to 1600 mJ. At lean conditions, the results showed adding microwave energy to a standard spark plug discharge increased the number of complete combustion cycles, improving engine stability as compared to spark-only operation. Addition of microwave energy also increased the indicated thermal efficiency by 4% at λ = 1.68. At λ = 1.75, the spark discharge alone was unable to consistently ignite the air-fuel mixture, resulting in frequent misfires. Although microwave energy produced more consistent ignition than spark discharge alone at λ = 1.75, 59% of the cycles only partially burned. Overall, the microwave-assisted spark plug increased engine performance under lean operating conditions (λ = 1.68) but did not affect operation at conditions closer to stoichiometric.« less

  7. Auto-ignition of toluene-doped n-heptane and iso-octane/air mixtures: High-pressure shock-tube experiments and kinetics modeling

    SciTech Connect

    Hartmann, M.; Fikri, M.; Schulz, C.; Gushterova, I.; Schiessl, R.; Maas, U.

    2011-01-15

    Toluene is often used as a fluorescent tracer for fuel concentration measurements, but without considering whether it affects the auto-ignition properties of the base fuel. We investigate the auto-ignition of pure toluene and its influence on the auto-ignition of n-heptane and iso-octane/air mixtures under engine-relevant conditions at typical tracer concentrations. Ignition delay times {tau}{sub ign} were measured behind reflected shock waves in mixtures with air at {phi}=1.0 and 0.5 at p=40 bar, over a temperature range of T=700-1200 K and compared to numerical results using two different mechanisms. Based on the models, information is derived about the relative influence of toluene on {tau}{sub ign} on the base fuels as function of temperature. For typical toluene tracer concentrations {<=}10%, the ignition delay time {tau}{sub ign} changes by less than 10% in the relevant pressure and temperature range. (author)

  8. DNS of the effects of thermal stratication and turbulent mixing on H2/air ignition in a constant volume, and comparison with the multi-zone model.

    SciTech Connect

    Sankaran, Ramanan; Chen, Jacqueline H.; Hawkes, Evatt R.; Im, Hong G.

    2005-01-01

    The influence of thermal stratification on auto-ignition at constant volume and high pressure is studied by Direct Numerical Simulation (DNS) with complex H{sub 2}/air chemistry with a view to providing better understanding of combustion processes in homogeneous charge compression ignition engines. In particular the dependence of overall ignition progress on initial mixture conditions is determined. The propagation speed of ignition fronts that emanate from 'hot spots' given by a temperature spectrum is monitored by using the displacement velocity of a scalar that tracks the location of maximum heat release. The evolution of the front velocity is compared for different initial temperature distributions and the role of scalar dissipation of heat and mass is identified. It is observed that both deagrative as well as spontaneous ignition front propagation occur depending upon the local temperature gradient. It is found that the ratio of the instantaneous front speed to the deflagrative speed is a good measure of the local mode of propagation. This is verified by examining the energy and species balances. A parametric study in the amplitudes of the initial temperature fluctuation is performed and shows that this parameter has a significant influence on the observed combustion mode. Higher levels of stratification lead to more front-like structures. Predictions of the multi-zone model are presented and explained using the diagnostics developed.

  9. Hot-spot contributions in shocked high explosives from mesoscale ignition models

    NASA Astrophysics Data System (ADS)

    Levesque, G.; Vitello, P.; Howard, W. M.

    2013-06-01

    High explosive performance and sensitivity is strongly related to the mesoscale defect densities. Bracketing the population of mesoscale hot spots that are active in the shocked ignition of explosives is important for the development of predictive reactive flow models. By coupling a multiphysics-capable hydrodynamics code (ale3d) with a chemical kinetics solver (cheetah), we can parametrically analyze different pore sizes undergoing collapse in high pressure shock conditions with evolving physical parameter fields. Implementing first-principles based decomposition kinetics, burning hot spots are monitored, and the regimes of pore sizes that contribute significantly to burnt mass faction and those that survive thermal conduction on the time scales of ignition are elucidated. Comparisons are drawn between the thermal explosion theory and the multiphysics models for the determination of nominal pore sizes that burn significantly during ignition for the explosive 1,3,5-triamino-2,4,6-trinitrobenzene.

  10. Catalytic ignition model in a monolithic reactor with in-depth reaction

    NASA Technical Reports Server (NTRS)

    Tien, Ta-Ching; Tien, James S.

    1990-01-01

    Two transient models have been developed to study the catalytic ignition in a monolithic catalytic reactor. The special feature in these models is the inclusion of thermal and species structures in the porous catalytic layer. There are many time scales involved in the catalytic ignition problem, and these two models are developed with different time scales. In the full transient model, the equations are non-dimensionalized by the shortest time scale (mass diffusion across the catalytic layer). It is therefore accurate but is computationally costly. In the energy-integral model, only the slowest process (solid heat-up) is taken as nonsteady. It is approximate but computationally efficient. In the computations performed, the catalyst is platinum and the reactants are rich mixtures of hydrogen and oxygen. One-step global chemical reaction rates are used for both gas-phase homogeneous reaction and catalytic heterogeneous reaction. The computed results reveal the transient ignition processes in detail, including the structure variation with time in the reactive catalytic layer. An ignition map using reactor length and catalyst loading is constructed. The comparison of computed results between the two transient models verifies the applicability of the energy-integral model when the time is greater than the second largest time scale of the system. It also suggests that a proper combined use of the two models can catch all the transient phenomena while minimizing the computational cost.

  11. Ignition Rate Measurement of Laser-Ignited Coals

    SciTech Connect

    John C. Chen; Vinayak Kabadi

    1997-10-31

    We established a novel experiment to study the ignition of pulverized coals under conditions relevant to utility boilers. Specifically, we determined the ignition mechanism of pulverized-coal particles under various conditions of particle size, coal type, and freestream oxygen concentration. We also measured the ignition rate constant of a Pittsburgh #8 high-volatile bituminous coal by direct measurement of the particle temperature at ignition, and incorporating this measurement into a mathematical model for the ignition process. The model, called Distributed Activation Energy Model of Ignition, was developed previously by our group to interpret conventional drop-tube ignition experiments, and was modified to accommodate the present study.

  12. Ignition conditions relaxation for central hot-spot ignition with an ion-electron non-equilibrium model

    NASA Astrophysics Data System (ADS)

    Fan, Zhengfeng; Liu, Jie

    2016-10-01

    We present an ion-electron non-equilibrium model, in which the hot-spot ion temperature is higher than its electron temperature so that the hot-spot nuclear reactions are enhanced while energy leaks are considerably reduced. Theoretical analysis shows that the ignition region would be significantly enlarged in the hot-spot rhoR-T space as compared with the commonly used equilibrium model. Simulations show that shocks could be utilized to create and maintain non-equilibrium conditions within the hot spot, and the hot-spot rhoR requirement is remarkably reduced for achieving self-heating. In NIF high-foot implosions, it is observed that the x-ray enhancement factors are less than unity, which is not self-consistent and is caused by assuming Te =Ti. And from this non-consistency, we could infer that ion-electron non-equilibrium exists in the high-foot implosions and the ion temperature could be 9% larger than the equilibrium temperature.

  13. Analysis of Spark-Ignition Engine Knock as Seen in Photographs Taken at 200,000 Frames Per Second

    NASA Technical Reports Server (NTRS)

    Miller, Cearcy D; Olsen, H Lowell; Logan, Walter O , Jr; Osterstrom, Gordon E

    1946-01-01

    A motion picture of the development of knock in a spark-ignition engine is presented, which consists of 20 photographs taken at intervals of 5 microseconds, or at a rate of 200,000 photographs per second, with an equivalent wide-open exposure time of 6.4 microseconds for each photograph. A motion picture of a complete combustion process, including the development of knock, taken at the rate of 40,000 photographs per second is also presented to assist the reader in orienting the photographs of the knock development taken at 200,000 frames per second.

  14. Properties, performance and emissions of medium concentration methanol-gasoline blends in a single-cylinder, spark-ignition engine

    SciTech Connect

    Sapre, A.R

    1988-01-01

    Methanol-gasoline blends containing 30 to 70 percent by volume methanol have potential to eliminate, or at least alleviate, major technical problems with the use of neat methanol such as safety, cold start and the reduced vehicle range. However, little information exits on their properties, performance and emissions. Experiments were carried out in a spark-ignited, single-cylinder, variable compression ratio, Waukesha RDH engine with primarily commercial grade unleaded gasoline, commercial grade methanol, M30, M50 and M70 methanol-gasoline blends to compare efficiency, performance and emissions characteristics. The fuels were compared at their knock-limited compression ratios and MBT spark-timing.

  15. Improvement of performance and emissions of a compression ignition methanol engine with dimethyl ether

    SciTech Connect

    Guo, J.; Chikahisa, Takemi; Murayama, Tadashi; Miyano, Masaharu

    1994-10-01

    Dimethyl ether (DME) has very good compression ignition characteristics and can be converted from methanol using a {gamma}-alumina catalyst. In this study a torch ignition chamber (TIC) head with TIC close to the center of the main combustion chamber was designed for the TIC method. The possibility of improvements in reducing the quantities of DME and emission were investigated by optimizing the TIC position, methanol injection timing, DME injection timing, and intake and exhaust throttling. It was found that the necessary amount of DME was greatly reduced when optimizing methanol and DME injection timings. 2 refs., 16 figs., 1 tab.

  16. Microinstability-based models for confinement properties and ignition criteria in tokamaks

    SciTech Connect

    Tang, W.M.; Bishop, C.M.; Coppi, B.; Kaye, S.M.; Perkins, F.W.; Redi, M.H.; Rewoldt, G.

    1987-02-01

    This paper reports on results of theoretical studies dealing with: (1) the use of microinstability-based thermal transport models to interpret the anomalous confinement properties observed in key tokamak experiments such as TFTR and (2) the likely consequences of the presence of such instabilities for future ignition devices. Transport code simulations using profile-consistent forms of anomalous thermal diffusivities due to drift-type instabilities have yielded good agreement with the confinement times and temperatures observed in TFTR under a large variety of operating conditions including pellet-fuelling in both ohmic- and neutral-beam-heated discharges. With regard to achieving an optimal ignition margin, the adverse temperature scaling of anomalous losses caused by drift modes leads to the conclusion that it is best to operate at the maximum allowable density while holding the temperature close to the minimum value required for ignition.

  17. Modeling of Thermophysical Processes in the Ignition of a Small Wooden Plank

    NASA Astrophysics Data System (ADS)

    Loboda, E. L.; Kasymov, D. P.; Yakimov, A. S.

    2015-01-01

    A formulation and a numerical solution based on a mathematical model of a porous reactive medium are given to the problem of ignition of a wooden plank by the action of a fire source. It is found that the ignition of the original reactant is determined by the processes of heat and mass exchange with the fire source, drying, and pyrolysis (decomposition and synthesis reactions) of a dry plank, by the reaction of oxidation of carbon dioxide, and also by the thermophysical properties of wood.

  18. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2003-01-01

    In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In a third embodiment, alternating short and long pulses of light from the excitation light source are directed into the ignitor laser. Each of the embodiments of the invention can be multiplexed so as to provide laser light energy sequentially to more than one ignitor laser.

  19. 14 CFR 33.69 - Ignitions system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ignitions system. 33.69 Section 33.69... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.69 Ignitions system. Each engine must be equipped with an ignition system for starting the engine on the ground and in flight. An...

  20. Systematic optimization of a detailed kinetic model using a methane ignition example

    NASA Technical Reports Server (NTRS)

    Frenklach, M.

    1984-01-01

    An approach to the systematic optimization of a large-scale dynamic model is proposed which consists in parameterization of simulation results as response surfaces. The optimization procedure is carried out using a second-order orthogonal design. The approach proposed here is demonstrated by an example involving the shock-initiated ignition of methane.

  1. EcoSmart Fire as structure ignition model in wildland urban interface: predictions and validations

    Treesearch

    Mark A. Dietenberger; Charles R. Boardman

    2016-01-01

    EcoSmartFire is a Windows program that models heat damage and piloted ignition of structures from radiant exposure to discrete landscaped tree fires. It calculates the radiant heat transfer from cylindrical shaped fires to the walls and roof of the structure while accounting for radiation shadowing, attenuation, and ground reflections. Tests of litter burn, a 0.6 m...

  2. Experimental and modeling study on effects of N2 and CO2 on ignition characteristics of methane/air mixture

    PubMed Central

    Zeng, Wen; Ma, Hongan; Liang, Yuntao; Hu, Erjiang

    2014-01-01

    The ignition delay times of methane/air mixture diluted by N2 and CO2 were experimentally measured in a chemical shock tube. The experiments were performed over the temperature range of 1300–2100 K, pressure range of 0.1–1.0 MPa, equivalence ratio range of 0.5–2.0 and for the dilution coefficients of 0%, 20% and 50%. The results suggest that a linear relationship exists between the reciprocal of temperature and the logarithm of the ignition delay times. Meanwhile, with ignition temperature and pressure increasing, the measured ignition delay times of methane/air mixture are decreasing. Furthermore, an increase in the dilution coefficient of N2 or CO2 results in increasing ignition delays and the inhibition effect of CO2 on methane/air mixture ignition is stronger than that of N2. Simulated ignition delays of methane/air mixture using three kinetic models were compared to the experimental data. Results show that GRI_3.0 mechanism gives the best prediction on ignition delays of methane/air mixture and it was selected to identify the effects of N2 and CO2 on ignition delays and the key elementary reactions in the ignition chemistry of methane/air mixture. Comparisons of the calculated ignition delays with the experimental data of methane/air mixture diluted by N2 and CO2 show excellent agreement, and sensitivity coefficients of chain branching reactions which promote mixture ignition decrease with increasing dilution coefficient of N2 or CO2. PMID:25750753

  3. Data Analysis, Pre-Ignition Assessment, and Post-Ignition Modeling of the Large-Scale Annular Cookoff Tests

    SciTech Connect

    G. Terrones; F.J. Souto; R.F. Shea; M.W.Burkett; E.S. Idar

    2005-09-30

    In order to understand the implications that cookoff of plastic-bonded explosive-9501 could have on safety assessments, we analyzed the available data from the large-scale annular cookoff (LSAC) assembly series of experiments. In addition, we examined recent data regarding hypotheses about pre-ignition that may be relevant to post-ignition behavior. Based on the post-ignition data from Shot 6, which had the most complete set of data, we developed an approximate equation of state (EOS) for the gaseous products of deflagration. Implementation of this EOS into the multimaterial hydrodynamics computer program PAGOSA yielded good agreement with the inner-liner collapse sequence for Shot 6 and with other data, such as velocity interferometer system for any reflector and resistance wires. A metric to establish the degree of symmetry based on the concept of time of arrival to pin locations was used to compare numerical simulations with experimental data. Several simulations were performed to elucidate the mode of ignition in the LSAC and to determine the possible compression levels that the metal assembly could have been subjected to during post-ignition.

  4. Experimental investigation of homogeneous charge compression ignition combustion of biodiesel fuel with external mixture formation in a CI engine.

    PubMed

    Ganesh, D; Nagarajan, G; Ganesan, S

    2014-01-01

    In parallel to the interest in renewable fuels, there has also been increased interest in homogeneous charge compression ignition (HCCI) combustion. HCCI engines are being actively developed because they have the potential to be highly efficient and to produce low emissions. Even though HCCI has been researched extensively, few challenges still exist. These include controlling the combustion at higher loads and the formation of a homogeneous mixture. To obtain better homogeneity, in the present investigation external mixture formation method was adopted, in which the fuel vaporiser was used to achieve excellent HCCI combustion in a single cylinder air-cooled direct injection diesel engine. In continuation of our previous works, in the current study a vaporised jatropha methyl ester (JME) was mixed with air to form a homogeneous mixture and inducted into the cylinder during the intake stroke to analyze the combustion, emission and performance characteristics. To control the early ignition of JME vapor-air mixture, cooled (30 °C) Exhaust gas recirculation (EGR) technique was adopted. The experimental result shows 81% reduction in NOx and 72% reduction in smoke emission.

  5. Relation Between Spark-Ignition Engine Knock, Detonation Waves, and Autoignition as Shown by High-Speed Photography

    NASA Technical Reports Server (NTRS)

    Miller, Cearcy D

    1946-01-01

    A critical review of literature bearing on the autoignition and detonation-wave theories of spark-ignition engine knock and on the nature of gas vibrations associated with combustion and knock results in the conclusion that neither the autoignition theory nor the detonation-wave theory is an adequate explanation of spark-ignition engine knock. A knock theory is proposed, combining the autoignition and detonation-wave theories, which introduces the idea that the detonation wave develops in autoignited or after-burning gases, and ascribes comparatively low-pitched heavy knocks to autoignition but high-pitched pinging knocks to detonation waves with the possibility of combinations of the two types of knocks. Analysis of five shots of knocking combustion, taken with the NACA high-speed motion-picture camera at the rate of 40,000 photographs per second reveals propagation speeds ranging from 3250 to more than 5500 feet per second. The range of propagation speeds from 3250 to more than 5500 feet per second is held to be considered with the proposed combined theory but not with either the simple autoignition theory or the simple detonation-wave theory.

  6. A Study by High-Speed Photography of Combustion and Knock in a Spark-Ignition Engine

    NASA Technical Reports Server (NTRS)

    Miller, Cearcy D

    1942-01-01

    The study of combustion in a spark-ignition engine given in Technical Report no. 704 has been continued. The investigation was made with the NACA high-speed motion-picture camera and the NACA optical engine indicator. The camera operates at the rate of 40,000 photographs a second and makes possible the study of phenomena occurring in time intervals as short as 0.000025 second. Photographs are presented of combustion without knock and with both light and heavy knocks, the end zone of combustion being within the field of view. Time-pressure records covering the same conditions as the photographs are presented and their relations to the photographs are studied. Photographs with ignition at various advance angles are compared with a view to observing any possible relationship between pressure and flame depth. A tentative explanation of knock is suggested, which is designed to agree with the indications of the high-speed photographs and the time-pressure records.

  7. Analysis of Spark-Ignition Engine Knock as Seen in Photographs Taken at 200,000 Frames Per Second

    NASA Technical Reports Server (NTRS)

    Miller, Cearcy D.; Olsen, H. Lowell; Logan, Walter O., Jr.; Osterstrom, Gordon E

    1946-01-01

    A motion picture of the development of knock in a spark-ignition engine, is presented, which consists of 20 photographs taken at intervals of 5 microseconds, or at a rate of 200,000 photographs a second, with an equivalent wide-open exposure time of 6.4 microseconds for each photograph. A motion picture of a complete combustion process, including the development of knock, taken at the rate of 40,000 photographs a second is also presented to assist the reader in orienting the photographs of the knock development taken at 200,000 frames per second. The photographs taken at 200,000 frames per second are analyzed and the conclusion is made that the type of knock in the spark-ignition engine involving violent gas vibration originates as self-propagating disturbance starting at a point in the.burn1ig or autoigniting gases and spreading out from that point through the incompletely burned gases at a rate as high as 6800 feet per second, or about twice the speed of sound in the burned gases. Apparent formation of free carbon particles in both the burning and the burned gas is observed within 10 microseconds after passage of the knock disturbance through the gases.

  8. Effects of a catalytic volatile particle remover (VPR) on the particulate matter emissions from a direct injection spark ignition engine.

    PubMed

    Xu, Fan; Chen, Longfei; Stone, Richard

    2011-10-15

    Emissions of fine particles have been shown to have a large impact on the atmospheric environment and human health. Researchers have shown that gasoline engines, especially direct injection spark ignition (DISI) engines, tend to emit large amounts of small size particles compared to diesel engines fitted with diesel particulate filters (DPFs). As a result, the particle number emissions of DISI engines will be restricted by the forthcoming EU6 legislation. The particulate emission level of DISI engines means that they could face some challenges in meeting the EU6 requirement. This paper is an experimental study on the size-resolved particle number emissions from a spray guided DISI engine and the performance of a catalytic volatile particle remover (VPR), as the EU legislation seeks to exclude volatile particles. The performance of the catalytic VPR was evaluated by varying its temperature and the exhaust residence time. The effect of the catalytic VPR acting as an oxidation catalyst on particle emissions was also tested. The results show that the catalytic VPR led to a marked reduction in the number of particles, especially the smaller size (nucleation mode) particles. The catalytic VPR is essentially an oxidation catalyst, and when post three-way catalyst (TWC) exhaust was introduced to the catalytic VPR, the performance of the catalytic VPR was not affected much by the use of additional air, i.e., no significant oxidation of the PM was observed.

  9. Particulate Matter Sampling and Volatile Organic Compound Removal for Characterization of Spark Ignited Direct Injection Engine Emissions

    SciTech Connect

    Matthias, Nicholas; Farron, Carolyn; Foster, David E.; Andrie, Michael; Krieger, Roger; Najt, Paul; Narayanaswamy, Kushal; Solomon, Arun; Zelenyuk, Alla

    2011-08-30

    More stringent emissions regulations are continually being proposed to mitigate adverse human health and environmental impacts of internal combustion engines. With that in mind, it has been proposed that vehicular particulate matter (PM) emissions should be regulated based on particle number in addition to particle mass. One aspect of this project is to study different sample handling methods for number based aerosol measurements, specifically, two different methods for removing volatile organic compounds (VOCs). One method is a thermodenuder (TD) and the other is an evaporative chamber/diluter (EvCh). These sample handling methods have been implemented in an engine test cell with a spark ignited direct injection (SIDI) engine. The engine was designed for stoichiometric, homogeneous combustion. SIDI is of particular interest for improved fuel efficiency compared to other SI engines, however, the efficiency benefit comes with greater PM emissions and may therefore be subject to the proposed number based PM regulation. Another aspect of this project is to characterize PM from this engine in terms of particle number and composition

  10. Particulate Matter Sampling and Volatile Organic Compound Removal for Characterization of Spark Ignited Direct Injection Engine Emissions

    SciTech Connect

    Matthias, Nicholas; Farron, Carrie; Foster, David E.; Andrie, Michael; Krieger, Roger; Najt, Paul M.; Narayanaswamy, Kushal; Solomon, Arun S.; Zelenyuk, Alla

    2012-01-01

    More stringent emissions regulations are continually being proposed to mitigate adverse human health and environmental impacts of internal combustion engines. With that in mind, it has been proposed that vehicular particulate matter (PM) emissions should be regulated based on particle number in addition to particle mass. One aspect of this project is to study different sample handling methods for number based aerosol measurements, specifically, two different methods for removing volatile organic compounds (VOCs). One method is a thermodenuder (TD) and the other is an evaporative chamber/diluter (EvCh). These sample handling methods have been implemented in an engine test cell with a spark ignited direct injection (SIDI) engine. The engine was designed for stoichiometric, homogeneous combustion. SIDI is of particular interest for improved fuel efficiency compared to other SI engines, however, the efficiency benefit comes with greater PM emissions and may therefore be subject to the proposed number based PM regulation. Another aspect of this project is to characterize PM from this engine in terms of particle number and composition.

  11. Performance and Emissions of a Small Compression Ignition Engine Run on Dual-fuel Mode (Diesel-Raw biogas)

    NASA Astrophysics Data System (ADS)

    Ambarita, H.; Sinulingga, E. P.; Nasution, M. KM; Kawai, H.

    2017-03-01

    In this work, a compression ignition (CI) engine is tested in dual-fuel mode (Diesel-Raw biogas). The objective is to examine the performance and emission characteristics of the engine when some of the diesel oil is replaced by biogas. The specifications of the CI engine are air cooled single horizontal cylinder, four strokes, and maximum output power of 4.86 kW. It is coupled with a synchronous three phase generator. The load, engine revolution, and biogas flow rate are varied from 600 W to 1500 W, 1000 rpm to 1500 rpm, 0 to 6 L/minute, respectively. The electric power, specific fuel consumption, thermal efficiency, gas emission, and diesel replacement ratio are analyzed. The results show that there is no significant difference of the power resulted by CI run on dual-fuel mode in comparison with pure diesel mode. However, the specific fuel consumption and efficiency decrease significantly as biogas flow rate increases. On the other hand, emission of the engine on dual-fuel mode is better. The main conclusion can be drawn is that CI engine without significant modification can be operated perfectly in dual-fuel mode and diesel oil consumption can be decreased up to 87.5%.

  12. Application of multicriteria decision making methods to compression ignition engine efficiency and gaseous, particulate, and greenhouse gas emissions.

    PubMed

    Surawski, Nicholas C; Miljevic, Branka; Bodisco, Timothy A; Brown, Richard J; Ristovski, Zoran D; Ayoko, Godwin A

    2013-02-19

    Compression ignition (CI) engine design is subject to many constraints, which present a multicriteria optimization problem that the engine researcher must solve. In particular, the modern CI engine must not only be efficient but must also deliver low gaseous, particulate, and life cycle greenhouse gas emissions so that its impact on urban air quality, human health, and global warming is minimized. Consequently, this study undertakes a multicriteria analysis, which seeks to identify alternative fuels, injection technologies, and combustion strategies that could potentially satisfy these CI engine design constraints. Three data sets are analyzed with the Preference Ranking Organization Method for Enrichment Evaluations and Geometrical Analysis for Interactive Aid (PROMETHEE-GAIA) algorithm to explore the impact of (1) an ethanol fumigation system, (2) alternative fuels (20% biodiesel and synthetic diesel) and alternative injection technologies (mechanical direct injection and common rail injection), and (3) various biodiesel fuels made from 3 feedstocks (i.e., soy, tallow, and canola) tested at several blend percentages (20-100%) on the resulting emissions and efficiency profile of the various test engines. The results show that moderate ethanol substitutions (~20% by energy) at moderate load, high percentage soy blends (60-100%), and alternative fuels (biodiesel and synthetic diesel) provide an efficiency and emissions profile that yields the most "preferred" solutions to this multicriteria engine design problem. Further research is, however, required to reduce reactive oxygen species (ROS) emissions with alternative fuels and to deliver technologies that do not significantly reduce the median diameter of particle emissions.

  13. The Effect of Compression Ratio, Fuel Octane Rating, and Ethanol Content on Spark-Ignition Engine Efficiency.

    PubMed

    Leone, Thomas G; Anderson, James E; Davis, Richard S; Iqbal, Asim; Reese, Ronald A; Shelby, Michael H; Studzinski, William M

    2015-09-15

    Light-duty vehicles (LDVs) in the United States and elsewhere are required to meet increasingly challenging regulations on fuel economy and greenhouse gas (GHG) emissions as well as criteria pollutant emissions. New vehicle trends to improve efficiency include higher compression ratio, downsizing, turbocharging, downspeeding, and hybridization, each involving greater operation of spark-ignited (SI) engines under higher-load, knock-limited conditions. Higher octane ratings for regular-grade gasoline (with greater knock resistance) are an enabler for these technologies. This literature review discusses both fuel and engine factors affecting knock resistance and their contribution to higher engine efficiency and lower tailpipe CO2 emissions. Increasing compression ratios for future SI engines would be the primary response to a significant increase in fuel octane ratings. Existing LDVs would see more advanced spark timing and more efficient combustion phasing. Higher ethanol content is one available option for increasing the octane ratings of gasoline and would provide additional engine efficiency benefits for part and full load operation. An empirical calculation method is provided that allows estimation of expected vehicle efficiency, volumetric fuel economy, and CO2 emission benefits for future LDVs through higher compression ratios for different assumptions on fuel properties and engine types. Accurate "tank-to-wheel" estimates of this type are necessary for "well-to-wheel" analyses of increased gasoline octane ratings in the context of light duty vehicle transportation.

  14. Residual Fuel Expulsion from a Simulated 50,000 Pound Thrust Liquid-Propellant Rocket Engine Having a Continuous Rocket-Type Igniter

    NASA Technical Reports Server (NTRS)

    Messing, Wesley E.

    1959-01-01

    Tests have been conducted to determine the starting characteristics of a 50,000-pound-thrust rocket engine with the conditions of a quantity of fuel lying dormant in the simulated main thrust chamber. Ignition was provided by a smaller rocket firing rearwardly along the center line. Both alcohol-water and anhydrous ammonia were used as the residual fuel. The igniter successfully expelled the maximum amount of residual fuel (3 1/2 gal) in 2.9 seconds when the igniter.was equipped with a sonic discharge nozzle operating at propellant flow rates of 3 pounds per second. Lesser amounts of residual fuel required correspondingly lower expulsion times. When the igniter was equipped with a supersonic exhaust nozzle operating at a flow of 4 pounds per second, a slightly less effective expulsion rate was encountered.

  15. Model predictions of higher-order normal alkane ignition from dilute shock-tube experiments

    NASA Astrophysics Data System (ADS)

    Rotavera, B.; Petersen, E. L.

    2013-07-01

    Shock-induced oxidation of two higher-order linear alkanes was measured using a heated shock tube facility. Experimental overlap in stoichiometric ignition delay times obtained under dilute (99 % Ar) conditions near atmospheric pressure was observed in the temperature-dependent ignition trends of n-nonane ( n-C9H20) and n-undecane ( n-C11H24). Despite the overlap, model predictions of ignition using two different detailed chemical kinetics mechanisms show discrepancies relative to both the measured data as well as to one another. The present study therefore focuses on the differences observed in the modeled, high-temperature ignition delay times of higher-order n-alkanes, which are generally regarded to have identical ignition behavior for carbon numbers above C7. Comparisons are drawn using experimental data from the present study and from recent work by the authors relative to two existing chemical kinetics mechanisms. Time histories from the shock-tube OH* measurements are also compared to the model predictions; a double-peaked structure observed in the data shows that the time response of the detector electronics is crucial for properly capturing the first, incipient peak near time zero. Calculations using the two mechanisms were carried out at the dilution level employed in the shock-tube experiments for lean {({φ} = 0.5)}, stoichiometric, and rich {({φ} = 2.0)} equivalence ratios, 1230-1620 K, and for both 1.5 and 10 atm. In general, the models show differing trends relative to both measured data and to one another, indicating that agreement among chemical kinetics models for higher-order n-alkanes is not consistent. For example, under certain conditions, one mechanism predicts the ignition delay times to be virtually identical between the n-nonane and n-undecane fuels (in fact, also for all alkanes between at least C8 and C12), which is in agreement with the experiment, while the other mechanism predicts the larger fuels to ignite progressively more slowly.

  16. Review of homogeneous charge compression ignition (HCCI) combustion engines and exhaust gas recirculation (EGR) effects on HCCI

    NASA Astrophysics Data System (ADS)

    Akma Tuan Kamaruddin, Tengku Nordayana; Wahid, Mazlan Abdul; Sies, Mohsin Mohd

    2012-06-01

    This paper describes the development in ICE which leads to the new advanced combustion mode named Homogeneous Charge Compression Ignition (HCCI). It explains regarding the theory and working principle of HCCI plus the difference of the process in gasoline and diesel fuelled engines. Many of pioneer and recent research works are discussed to get the current state of art about HCCI. It gives a better indication on the potential of this method in improving the fuel efficiency and emission produced by the vehicles' engine. Apart from the advantages, the challenges and future trend of this technology are also included. HCCI is applying few types of control strategy in producing the optimum performance. This paper looks into Exhaust Gas Recirculation (EGR) as one of the control strategies.

  17. Compression Ignition Engines - revolutionary technology that has civilized frontiers all over the globe from the Industrial Revolution into the 21st Century

    SciTech Connect

    Ciatti, Stephen A.

    2015-06-24

    The history, present and future of the compression ignition engine is a fascinating story that spans over 100 years, from the time of Rudolf Diesel to the highly regulated and computerized engines of the 21st Century. The development of these engines provided inexpensive, reliable and high power density machines to allow transportation, construction and farming to be more productive with less human effort than in any previous period of human history. The concept that fuels could be consumed efficiently and effectively with only the ignition of pressurized and heated air was a significant departure from the previous coal-burning architecture of the 1800s. Today, the compression ignition engine is undergoing yet another revolution. The equipment that provides transport, builds roads and infrastructure, and harvests the food we eat needs to meet more stringent requirements than ever before. How successfully 21st Century engineers are able to make compression ignition engine technology meet these demands will be of major influence in assisting developing nations (with over 50% of the world’s population) achieve the economic and environmental goals they seek.

  18. Schlieren Imaging and Pulsed Detonation Engine Testing of Ignition by a Nanosecond Repetitively Pulsed Discharge

    DTIC Science & Technology

    2016-05-16

    temperature is sufficiently high so that chain branch- ing chemistry can occur. Figure 9b presents the effect of different degrees of O atom ...indicated that reactions of excited species mainly lead to the production of O atoms and the increase of gas temperature, which shortens induction... chemistry timescales, and thus reduces the flame-development time through both kinetic and thermal mechanisms. Ignition of aviation gasoline–air mixtures

  19. A numerical study on combustion process in a small compression ignition engine run dual-fuel mode (diesel-biogas)

    NASA Astrophysics Data System (ADS)

    Ambarita, H.; Widodo, T. I.; Nasution, D. M.

    2017-01-01

    In order to reduce the consumption of fossil fuel of a compression ignition (CI) engines which is usually used in transportation and heavy machineries, it can be operated in dual-fuel mode (diesel-biogas). However, the literature reviews show that the thermal efficiency is lower due to incomplete combustion process. In order to increase the efficiency, the combustion process in the combustion chamber need to be explored. Here, a commercial CFD code is used to explore the combustion process of a small CI engine run on dual fuel mode (diesel-biogas). The turbulent governing equations are solved based on finite volume method. A simulation of compression and expansions strokes at an engine speed and load of 1000 rpm and 2500W, respectively has been carried out. The pressure and temperature distributions and streamlines are plotted. The simulation results show that at engine power of 732.27 Watt the thermal efficiency is 9.05%. The experiment and simulation results show a good agreement. The method developed in this study can be used to investigate the combustion process of CI engine run on dual-fuel mode.

  20. Ignition problems in scramjet testing

    SciTech Connect

    Mitani, Tohru

    1995-05-01

    Ignition of H{sub 2} in heated air containing H{sub 2}O, radicals, and dust was investigated for scramjet testing. Using a reduced kinetic model for H{sub 2}{minus}O{sub 2} systems, the effects of H{sub 2}O and radicals in nozzles are discussed in relation to engine testing with vitiation heaters. Analysis using linearized rate-equations suggested that the addition of O atoms was 1.5 times more effective than the addition of H atoms for ignition. This result can be applied to the problem of premature ignition caused by residual radicals and to plasma-jet igniters. Thermal and chemical effects of dust, inevitable in storage air heaters, were studied next. The effects of heat capacity and size of dust were expressed in terms of an exponential integral function. It was found that the radical termination on the surface of dust produces an effect equivalent to heat loss. The inhibition of ignition by dust may result, if the mass fraction of dust becomes 10{sup {minus}3}.

  1. Maximizing Power Output in Homogeneous Charge Compression Ignition (HCCI) Engines and Enabling Effective Control of Combustion Timing

    NASA Astrophysics Data System (ADS)

    Saxena, Samveg

    Homogeneous Charge Compression Ignition (HCCI) engines are one of the most promising engine technologies for the future of energy conversion from clean, efficient combustion. HCCI engines allow high efficiency and lower CO2 emission through the use of high compression ratios and the removal of intake throttle valves (like Diesel), and allow very low levels of urban pollutants like nitric oxide and soot (like Otto). These engines, however, are not without their challenges, such as low power density compared with other engine technologies, and a difficulty in controlling combustion timing. This dissertation first addresses the power output limits. The particular strategies for enabling high power output investigated in this dissertation focus on avoiding five critical limits that either damage an engine, drastically reduce efficiency, or drastically increase emissions: (1) ringing limits, (2) peak in-cylinder pressure limits, (3) misfire limits, (4) low intake temperature limits, and (5) excessive emissions limits. The research shows that the key factors that enable high power output, sufficient for passenger vehicles, while simultaneously avoiding the five limits defined above are the use of: (1) high intake air pressures allowing improved power output, (2) highly delayed combustion timing to avoid ringing limits, and (3) using the highest possible equivalence ratio before encountering ringing limits. These results are revealed by conducting extensive experiments spanning a wide range of operating conditions on a multi-cylinder HCCI engine. Second, this dissertation discusses strategies for effectively sensing combustion characteristics on a HCCI engine. For effective feedback control of HCCI combustion timing, a sensor is required to quantify when combustion occurs. Many laboratory engines use in-cylinder pressure sensors but these sensors are currently prohibitively expensive for wide-scale commercialization. Instead, ion sensors made from inexpensive sparkplugs

  2. Principles of models based engineering

    SciTech Connect

    Dolin, R.M.; Hefele, J.

    1996-11-01

    This report describes a Models Based Engineering (MBE) philosophy and implementation strategy that has been developed at Los Alamos National Laboratory`s Center for Advanced Engineering Technology. A major theme in this discussion is that models based engineering is an information management technology enabling the development of information driven engineering. Unlike other information management technologies, models based engineering encompasses the breadth of engineering information, from design intent through product definition to consumer application.

  3. Cycle-by-cycle combustion variations in spark-ignited engines

    SciTech Connect

    Daw, C.S.; Finney, C.E.A.; Connolly, F.T.

    1997-09-01

    Under constant nominal operating conditions, internal combustion engines can exhibit substantial variation in combustion efficiency from one cycle to the next. Previous researchers have attempted to explain these variations as resulting from stochastic, linear, or chaotic physical processes. Our investigations indicate that cyclic combustion variations can be explained as the result of interactions between a global low-dimensional nonlinearity and small-scale, high-dimensional processes that perturb the nonlinearity. Using this approach, we have proposed a simple model that accurately simulates experimentally observed patterns in cyclic combustion variations. Our model also explains the apparent discrepancies among previous investigators regarding the basic nature of cyclic variations. Further, it appears that symbol dynamics are useful for characterizing the observed model and experimental behavior.

  4. ALE3D Simulations of Gap Closure and Surface Ignition for Cookoff Modeling

    SciTech Connect

    Howard, W M; McClelland, M A; Nichols, A L

    2006-06-22

    We are developing ALE3D models to describe the thermal, chemical and mechanical behavior during the heating, ignition and explosive phases of various cookoff phenomena. The candidate models and numerical strategies are being evaluated using benchmark cookoff experiments. ALE3D is a three-dimensional computer code capable of solving the model equations in a coupled fashion through all the phases of the cookoff in a single calculation. For the cookoff experiments, we are interested in representing behavior on widely varying timescales. We have used an implicit hydrodynamics option during the heating phase and an explicit solution method during the explosive phase. To complicate the modeling problem, high heat fluxes cause rapid temperature increases in boundary layers and lead to the formation of gaps between energetic and structural materials and ignition on surfaces. The initially solid energetic and structural materials react to produce gases, which fill the gaps. These materials can also melt and flow. Since an implicit solution method is used, simple no-strength materials models can no longer be used for liquids and gases. In this paper, we discuss and demonstrate choices of materials models for solid/liquid/gas mixtures to be used in conjunction with the implicit solution method. In addition, results are given for mesh movement strategies applied to the opening, closing, and surface ignition within gaps.

  5. Ignition-and-Growth Modeling of NASA Standard Detonator and a Linear Shaped Charge

    NASA Technical Reports Server (NTRS)

    Oguz, Sirri

    2010-01-01

    The main objective of this study is to quantitatively investigate the ignition and shock sensitivity of NASA Standard Detonator (NSD) and the shock wave propagation of a linear shaped charge (LSC) after being shocked by NSD flyer plate. This combined explosive train was modeled as a coupled Arbitrary Lagrangian-Eulerian (ALE) model with LS-DYNA hydro code. An ignition-and-growth (I&G) reactive model based on unreacted and reacted Jones-Wilkins-Lee (JWL) equations of state was used to simulate the shock initiation. Various NSD-to-LSC stand-off distances were analyzed to calculate the shock initiation (or failure to initiate) and detonation wave propagation along the shaped charge. Simulation results were verified by experimental data which included VISAR tests for NSD flyer plate velocity measurement and an aluminum target severance test for LSC performance verification. Parameters used for the analysis were obtained from various published data or by using CHEETAH thermo-chemical code.

  6. High-speed fuel tracer fluorescence and OH radical chemiluminescence imaging in a spark-ignition direct-injection engine

    NASA Astrophysics Data System (ADS)

    Smith, James D.; Sick, Volker

    2005-11-01

    An innovative technique has been demonstrated to achieve crank-angle-resolved planar laser-induced fluorescence (PLIF) of fuel followed by OH* chemiluminescence imaging in a firing direct-injected spark-ignition engine. This study used two standard KrF excimer lasers to excite toluene for tracking fuel distribution. The intensified camera system was operated at single crank-angle resolution at 2000 revolutions per minute (RPM) for 500 consecutive cycles. Through this work, it has been demonstrated that toluene and OH* can be imaged through the same optical setup while similar signal levels are obtained from both species, even at these high rates. The technique is useful for studying correlations between fuel distribution and subsequent ignition and flame propagation without the limitations of phase-averaging imaging approaches. This technique is illustrated for the effect of exhaust gas recirculation on combustion and will be useful for studies of misfire causes. Finally, a few general observations are presented as to the effect of preignition fuel distribution on subsequent combustion.

  7. High-speed fuel tracer fluorescence and OH radical chemiluminescence imaging in a spark-ignition direct-injection engine.

    PubMed

    Smith, James D; Sick, Volker

    2005-11-01

    An innovative technique has been demonstrated to achieve crank-angle-resolved planar laser-induced fluorescence (PLIF) of fuel followed by OH* chemiluminescence imaging in a firing direct-injected spark-ignition engine. This study used two standard KrF excimer lasers to excite toluene for tracking fuel distribution. The intensified camera system was operated at single crank-angle resolution at 2000 revolutions per minute (RPM) for 500 consecutive cycles. Through this work, it has been demonstrated that toluene and OH* can be imaged through the same optical setup while similar signal levels are obtained from both species, even at these high rates. The technique is useful for studying correlations between fuel distribution and subsequent ignition and flame propagation without the limitations of phase-averaging imaging approaches. This technique is illustrated for the effect of exhaust gas recirculation on combustion and will be useful for studies of misfire causes. Finally, a few general observations are presented as to the effect of preignition fuel distribution on subsequent combustion.

  8. Effect of air-entry angle on performance of a 2-stroke-cycle compression-ignition engine

    NASA Technical Reports Server (NTRS)

    Earle, Sherod L; Dutee, Francis J

    1937-01-01

    An investigation was made to determine the effect of variations in the horizontal and vertical air-entry angles on the performance characteristics of a single-cylinder 2-stroke-cycle compression-ignition test engine. Performance data were obtained over a wide range of engine speed, scavenging pressure, fuel quantity, and injection advance angle with the optimum guide vanes. Friction and blower-power curves are included for calculating the indicated and net performances. The optimum horizontal air-entry angle was found to be 60 degrees from the radial and the optimum vertical angle to be zero, under which conditions a maximum power output of 77 gross brake horsepower for a specific fuel consumption of 0.52 pound per brake horsepower-hour was obtained at 1,800 r.p.m. and 16-1/2 inches of Hg scavenging pressure. The corresponding specific output was 0.65 gross brake horsepower per cubic inch of piston displacement. Tests revealed that the optimum scavenging pressure increased linearly with engine speed. The brake mean effective pressure increased uniformly with air quantity per cycle for any given vane angle and was independent of engine speed and scavenging pressure.

  9. Ignition and combustion of lunar propellants

    NASA Technical Reports Server (NTRS)

    Burton, Rodney L.; Roberts, Ted A.; Krier, Herman

    1993-01-01

    The ignition and combustion of Al, Mg, and Al/Mg alloy particles in 99 percent O2/1 percent N2 mixtures is investigated at high temperatures and pressures for rocket engine applications. The 20 micron particles contain 0, 5, 10, 20, 40, 60, 80, and 100 weight percent Mg alloyed with Al, and are ignited in oxygen using the reflected shock in a shock tube near the endwall. Using this technique, the ignition delay and combustion times of the particles are measured at temperatures up to 3250 K as a function of Mg content for oxygen pressures of 8.5, 17, and 34 atm. An ignition model is developed which employs a simple lumped capacitance energy equation and temperature and pressure dependent particle and gas properties. Good agreement is achieved between the measured and predicted trends in the ignition delay times. For the particles investigated, the contribution of heterogeneous reaction to the heating of the particle is found to be significant at lower temperatures, but may be neglected as gas temperatures above 3000 K. As little as 10 percent Mg reduces the ignition delay time substantially at all pressures tested. The particle ignition delay times decrease with increasing Mg content, and this reduction becomes less pronounced as oxidizer temperature and pressure are increased.

  10. Effect of different charged particle stopping power models on ICG ignition

    NASA Astrophysics Data System (ADS)

    Terry, Matthew R.

    Thermonuclear fusion holds the potential to be a source of clean abundant energy. Inertial confinement fusion (ICF) is one means of achieving significant, controlled fusion burn. In ICF, a small amount of frozen deuterium/tritium fuel is compressed to many times solid density and temperatures greater than 10,000 eV. In these targets, fusion burn initiates in a low density hot spot and then propagates into the cold fuel. The burn wave propagates by way of fusion products being born in the hot spot then slowing down in the fuel and heating it in the process. In this thesis, we study the stopping power models that describe charged particle slowing. In particular, we analyze the assumptions made in theses models and how those assumptions limit the use of these models in ICF ignition conditions. We implement twelve of these models in a stopping power library called "Deeks" that includes both the stopping power calculations and the consistency constraints of the models. We then integrate Deeks into a 1D multi-physics radiation-hydrodynamics code called "Bucky" to perform integrated target implosions with the stopping power calculations of the fusion product transport performed by Deeks. We use a shock ignition target as a test bed to compare the effect of different stopping power models on target performance. As some fraction of target conditions are expected to be outside many models consistency constraints, we use a three tiered model for calculating stopping powers that gradually degrades to simpler models as target conditions get further away from conditions consistent with the stopping power model's derivation. We find the conditions of the cold fuel to be substantially inconsistent with the ubiquitous assumption of weak plasma coupling and the application of weakly coupled stopping power models to ICF ignition to be very limited. Finally, facilitate the use of shock ignition targets as a fusion burn test-bed, we have developed a program for automatically tuning a

  11. SHOCK INITIATION EXPERIMENTS ON THE TATB BASED EXPLOSIVE RX-03-GO WITH IGNITION AND GROWTH MODELING

    SciTech Connect

    Vandersall, K S; Garcia, F; Tarver, C M

    2009-06-23

    Shock initiation experiments on the TATB based explosive RX-03-GO (92.5% TATB, 7.5% Cytop A by weight) were performed to obtain in-situ pressure gauge data, characterize the run-distance-to-detonation behavior, and calculate Ignition and Growth modeling parameters. A 101 mm diameter propellant driven gas gun was utilized to initiate the explosive sample with manganin piezoresistive pressure gauge packages placed between sample slices. The RX-03-GO formulation utilized is similar to that of LX-17 (92.5% TATB, 7.5% Kel-f by weight) with the notable differences of a new binder material and TATB that has been dissolved and recrystallized in order to improve the purity and morphology. The shock sensitivity will be compared with that of prior data on LX-17 and other TATB formulations. Ignition and Growth modeling parameters were obtained with a reasonable fit to the experimental data.

  12. Shock initiation experiments with ignition and growth modeling on low density composition B

    NASA Astrophysics Data System (ADS)

    Vandersall, Kevin S.; Garcia, Frank; Tarver, Craig M.

    2017-01-01

    Shock initiation experiments on low density (˜1.2 and ˜1.5 g/cm3) Composition B were performed to obtain in-situ pressure gauge data, characterize the run-distance-to-detonation behavior, and provide a basis for Ignition and Growth reactive flow modeling. A 101 mm diameter gas gun was utilized to initiate the explosive charges with manganin piezoresistive pressure gauge packages placed between packed layers (˜1.2 g/cm3) confined in Teflon rings or sample disks pressed to low density (˜1.5 g/cm3). The shock sensitivity was found to increase with decreasing density as expected. Ignition and Growth model parameters were derived that yielded reasonable agreement with the experimental data at both initial densities. The shock sensitivity at the tested densities are compared to prior published work with near full density material.

  13. SHOCK INITIATION EXPERIMENTS ON PBX9501 EXPLOSIVE AT 150?C FOR IGNITION AND GROWTH MODELING

    SciTech Connect

    Vandersall, K S; Tarver, C M; Garcia, F; Urtiew, P A

    2005-07-19

    Shock initiation experiments on the explosive PBX9501 (95% HMX, 2.5% estane, and 2.5% nitroplasticizer by weight) were performed at 150 C to obtain in-situ pressure gauge data and Ignition and Growth modeling parameters. A 101 mm diameter propellant driven gas gun was utilized to initiate the PBX9501 explosive with manganin piezoresistive pressure gauge packages placed between sample slices. The run-distance-to-detonation points on the Pop-plot for these experiments showed agreement with previously published data and Ignition and Growth modeling parameters were obtained with a good fit to the experimental data. This parameter set will allow accurate code predictions to be calculated for safety scenarios involving PBX9501 explosives at temperatures close to 150 C.

  14. Shock initiation experiments with ignition and growth modeling on low density HMX

    NASA Astrophysics Data System (ADS)

    Garcia, Frank; Vandersall, Kevin S.; Tarver, Craig M.

    2014-05-01

    Shock initiation experiments on low density (~1.2 and ~1.6 g/cm3) HMX were performed to obtain in-situ pressure gauge data, characterize the run-distance-to-detonation behavior, and provide a basis for Ignition and Growth reactive flow modeling. A 101 mm diameter gas gun was utilized to initiate the explosive charges with manganin piezoresistive pressure gauge packages placed between packed layers (~1.2 g/cm3) or sample disks pressed to low density (~1.6 g/cm3). The measured shock sensitivity of the ~1.2 g/cm3 HMX was similar to that previously measured by Sheffield et al. and the ~1.6 g/cm3 HMX was measured to be much less shock sensitive. Ignition and Growth model parameters were utilized that yielded good agreement with the experimental data at both initial densities.

  15. Shock Initiation Experiments Plus Ignition and Growth Modeling of PBXN-112

    NASA Astrophysics Data System (ADS)

    Garcia, Frank; Vandersall, Kevin; Tarver, Craig

    2011-06-01

    Shock initiation experiments on the HMX based explosive PBXN-112 (89% HMX, 11% polyaurylmethacrylate by weight) were performed to obtain in-situ pressure gauge data, to characterize the run-distance-to-detonation behavior, and to provide a basis for Ignition and Growth reactive flow modeling. A 101 mm diameter gas gun was utilized to initiate the explosive charge with manganin piezoresistive pressure gauge packages placed between sample slices. The shock sensitivity of PBXN-112 is compared to that of other HMX formulations. Ignition and Growth model parameters were derived that yielded a good fit to the experimental data. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  16. Shock Initiation Experiments on the Tatb Based Explosive RX-03-GO with Ignition and Growth Modeling

    NASA Astrophysics Data System (ADS)

    Vandersall, Kevin S.; Garcia, Frank; Tarver, Craig M.

    2009-12-01

    Shock initiation experiments on the TATB based explosive RX-03-GO (92.5% TATB, 7.5% Cytop A by weight) were performed to obtain in-situ pressure gauge data, characterize the run-distance-to-detonation behavior, and calculate Ignition and Growth modeling parameters. A 101 mm diameter propellant driven gas gun was utilized to initiate the explosive sample with manganin piezoresistive pressure gauge packages placed between sample slices. The RX-03-GO formulation utilized is similar to that of LX-17 (92.5% TATB, 7.5% Kel-f by weight) with the notable differences of a new binder material and TATB that has been dissolved and recrystallized in order to improve the purity and morphology. The shock sensitivity will be compared with that of prior data on LX-17 and other TATB formulations. Ignition and Growth modeling parameters were obtained with a reasonable fit to the experimental data.

  17. Models to estimate the minimum ignition temperature of dusts and hybrid mixtures.

    PubMed

    Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

    2016-03-05

    The minimum ignition temperatures (MIT) of hybrid mixtures have been investigated by performing several series of tests in a modified Godbert-Greenwald furnace. Five dusts as well as three perfect gases and three real were used in different combinations as test samples. Further, seven mathematical models for prediction of the MIT of dust/air mixtures were presented of which three were chosen for deeper study and comparison with the experimental results based on the availability of the input quantities needed and their applicability. Additionally, two alternative models were proposed to calculate the MIT of hybrid mixtures and were validated against the experimental results. A significant decrease of the minimum ignition temperature of either the gas or the vapor as well as an increase in the explosion likelihood could be observed when a small amount of dust which was either below its minimum explosible concentration or not ignitable itself at that particular temperature was mixed with the gas. The various models developed by Cassel, Krishma and Mitsui to predict the MIT of dust were in good agreement with the experimental results as well as the two models proposed to predict the MIT of hybrid mixtures were also in agreement with the experimental value.

  18. A High-Speed Motion-Picture Study of Normal Combustion, Knock and Preignition in a Spark-Ignition Engines

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Spencer, R C; Miller, Cearcy D

    1941-01-01

    Combustion in a spark-ignition engine was investigated by means of the NACA high-speed motion-picture cameras. This camera is operated at a speed of 40,000 photographs a second and therefore makes possible the study of changes that take place in the intervals as short as 0.000025 second. When the motion pictures are projected at the normal speed of 16 frames a second, any rate of movement shown is slowed down 2500 times. Photographs are presented of normal combustion, of combustion from preignitions, and of knock both with and without preignition. The photographs of combustion show that knock may be preceded by a period of exothermic reaction in the end zone that persists for a time interval of as much as 0.0006 second. The knock takes place in 0.00005 second or less.

  19. Ignition of an automobile engine by high-peak power Nd:YAG/Cr⁴⁺:YAG laser-spark devices.

    PubMed

    Pavel, Nicolaie; Dascalu, Traian; Salamu, Gabriela; Dinca, Mihai; Boicea, Niculae; Birtas, Adrian

    2015-12-28

    Laser sparks that were built with high-peak power passively Q-switched Nd:YAG/Cr(4+):YAG lasers have been used to operate a Renault automobile engine. The design of such a laser spark igniter is discussed. The Nd:YAG/Cr(4+):YAG laser delivered pulses with energy of 4 mJ and 0.8-ns duration, corresponding to pulse peak power of 5 MW. The coefficients of variability of maximum pressure (COV(Pmax)) and of indicated mean effective pressure (COV(IMEP)) and specific emissions like hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO(x)) and carbon dioxide (CO2) were measured at various engine speeds and high loads. Improved engine stability in terms of COV(Pmax) and COV(Pmax) and decreased emissions of CO and HC were obtained for the engine that was run by laser sparks in comparison with classical ignition by electrical spark plugs.

  20. Modeling and cold start in alcohol-fueled engines

    SciTech Connect

    Markel, A.J.; Bailey, B.K.

    1998-05-01

    Neat alcohol fuels offer several benefits over conventional gasoline in automotive applications. However, their low vapor pressure and high heat of vaporization make it difficult to produce a flammable vapor composition from a neat alcohol fuel during a start under cold ambient conditions. Various methods have been introduced to compensate for this deficiency. In this study, the authors applied computer modeling and simulation to evaluate the potential of four cold-start technologies for engines fueled by near-neat alcohol. The four technologies were a rich combustor device, a partial oxidation reactor, a catalytic reformer, and an enhanced ignition system. The authors ranked the competing technologies by their ability to meet two primary criteria for cold starting an engine at {minus}25 deg C and also by several secondary parameters related to commercialization. Their analysis results suggest that of the four technologies evaluated, the enhanced ignition system is the best option for further development.

  1. Conversion of a Micro, Glow-Ignition, Two-Stroke Engine from Nitromethane-Methanol Blend Fuel to Military Jet Propellant (JP-8)

    DTIC Science & Technology

    2012-01-01

    encased in a ceramic coating. This ceramic coating was then coated with platinum catalysis paint . During the compression stroke of the engine, a small...experiments, the adhesive that held the probe’s internal components together was melted and the sensor failed. If another micro engine test stand is built...turns open, but no ignition was observed. Calling on personal experience, a propane torch was used to heat the cylinder head to 80°C. Again, the

  2. Effects of Corona, Spark and Surface Discharges on Ignition Delay and Deflagration-to-Detonation Times in Pulsed Detonation Engines (Postprint)

    DTIC Science & Technology

    2006-12-01

    AFRL-RZ-WP-TP-2008-2034 EFFECTS OF CORONA, SPARK AND SURFACE DISCHARGES ON IGNITION DELAY AND DEFLAGRATION-TO-DETONATION TIMES IN PULSED ...DETONATION ENGINES (POSTPRINT) Kenneth Busby, Jennifer Corrigan , Sheng-Tao Yu, Skip Williams, Campbell D. Carter, Frederick Schauer, John Hoke...DELAY AND DEFLAGRATION-TO-DETONATION TIMES IN PULSED DETONATION ENGINES (POSTPRINT) 5c. PROGRAM ELEMENT NUMBER 61102F 5d. PROJECT NUMBER 2308 5e

  3. Optimization of a Small-Scale Engine Using Plasma Enhanced Ignition

    DTIC Science & Technology

    2013-03-01

    incapable of motoring the engine, a 24 V DC electric motor was mounted next to the engine. A timing belt pulley (M in Figure 4) with a one way bearing (L...associated hardware; body of the engine and dynamometer are not shown: A) engine shaft, B) engine hub, C) 60 minus 2 tooth spur gear flywheel, D) single...keyed dynamometer collar, J) dynamometer shaft, K) rear side shaft extension, L) one-way bearing, M) starter timing belt pulley , N) encoder timing

  4. Performance of a small compression ignition engine fuelled by liquified petroleum gas

    NASA Astrophysics Data System (ADS)

    Ambarita, Himsar; Yohanes Setyawan, Eko; Ginting, Sibuk; Naibaho, Waldemar

    2017-09-01

    In this work, a small air cooled single cylinder of diesel engine with a rated power of 2.5 kW at 3000 rpm is tested in two different modes. In the first mode, the CI engines run on diesel fuel mode. In the second mode, the CI engine run on liquified petroleum gas (LPG) mode. In order to simulate the load, a generator is employed. The load is fixed at 800 W and engine speed varies from 2400 rpm to 3400 rpm. The out power, specific fuel consumption, and brake thermal efficiency resulted from the engine in both modes are compared. The results show that the output power of the CI engine run on LPG fuel is comparable with the engine run on diesel fuel. However, the specific fuel consumption of the CI engine with LPG fuel is higher 17.53% in average in comparison with the CI engine run on diesel fuel. The efficiency of the CI engine with LPG fuel is lower 21.43% in average in comparison with the CI engine run on diesel fuel.

  5. Performance of a Compression-ignition Engine with a Precombustion Chamber Having High-Velocity Air Flow

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Moore, C S

    1931-01-01

    Presented here are the results of performance tests made with a single-cylinder, four stroke cycle, compression-ignition engine. These tests were made on a precombustion chamber type of cylinder head designed to have air velocity and tangential air flow in both the chamber and cylinder. The performance was investigated for variable load and engine speed, type of fuel spray, valve opening pressure, injection period and, for the spherical chamber, position of the injection spray relative to the air flow. The pressure variations between the pear-shaped precombustion chamber and the cylinder for motoring and full load conditions were determined with a Farnboro electric indicator. The combustion chamber designs tested gave good mixing of a single compact fuel spray with the air, but did not control the ensuing combustion sufficiently. Relative to each other, the velocity of air flow was too high, the spray dispersion by injection too great, and the metering effect of the cylinder head passage insufficient. The correct relation of these factors is of the utmost importance for engine performance.

  6. Investigation on the gaseous and particulate emissions of a compression ignition engine fueled with diesel-dimethyl carbonate blends.

    PubMed

    Cheung, C S; Zhu, Ruijun; Huang, Zuohua

    2011-01-01

    The effect of dimethyl carbonate (DMC) on the gaseous and particulate emissions of a diesel engine was investigated using Euro V diesel fuel blended with different proportions of DMC. Combustion analysis shows that, with the blended fuel, the ignition delay and the heat release rate in the premixed combustion phase increase, while the total combustion duration and the fuel consumed in the diffusion combustion phase decrease. Compared with diesel fuel, with an increase of DMC in the blended fuel, the brake thermal efficiency is slightly improved but the brake specific fuel consumption increases. On the emission side, CO increases significantly at low engine load but decreases at high engine load while HC decreases slightly. NO(x) reduces slightly but the reduction is not statistically significant, while NO(2) increases slightly. Particulate mass and number concentrations decrease upon using the blended fuel while the geometric mean diameter of the particles shifts towards smaller size. Overall speaking, diesel-DMC blends lead to significant improvement in particulate emissions while the impact on CO, HC and NO(x) emissions is small.

  7. Physicochemical characterization of particulate emissions from a compression ignition engine employing two injection technologies and three fuels.

    PubMed

    Surawski, N C; Miljevic, B; Ayoko, G A; Roberts, B A; Elbagir, S; Fairfull-Smith, K E; Bottle, S E; Ristovski, Z D

    2011-07-01

    Alternative fuels and injection technologies are a necessary component of particulate emission reduction strategies for compression ignition engines. Consequently, this study undertakes a physicochemical characterization of diesel particulate matter (DPM) for engines equipped with alternative injection technologies (direct injection and common rail) and alternative fuels (ultra low sulfur diesel, a 20% biodiesel blend, and a synthetic diesel). Particle physical properties were addressed by measuring particle number size distributions, and particle chemical properties were addressed by measuring polycyclic aromatic hydrocarbons (PAHs) and reactive oxygen species (ROS). Particle volatility was determined by passing the polydisperse size distribution through a thermodenuder set to 300 °C. The results from this study, conducted over a four point test cycle, showed that both fuel type and injection technology have an impact on particle emissions, but injection technology was the more important factor. Significant particle number emission (54%-84%) reductions were achieved at half load operation (1% increase-43% decrease at full load) with the common rail injection system; however, the particles had a significantly higher PAH fraction (by a factor of 2 to 4) and ROS concentrations (by a factor of 6 to 16) both expressed on a test-cycle averaged basis. The results of this study have significant implications for the health effects of DPM emissions from both direct injection and common rail engines utilizing various alternative fuels.

  8. Modeling of Plasma-Induced Ignition and Combustion

    DTIC Science & Technology

    2008-01-11

    model adapted from work by Keidar et al [9]. To model a propellant we require the vapor pressure, enthalpy of sublimation (∆H), specific heat at...neutral density is found from the PPI model, where the neutral number density is given by nn = PV (Ts)/(kTs), where PV (Ts) is the propellant vapor ... vapor pressure. It was found for the surface temperature range predicted by the PPI model (300 K ≤ Ts ≤ 1200 K) and for the conditions of the

  9. Numerical Analysis of Autoignition and Combustion of n-Butane and Air Mixture in Homogeneous-Charge Compression-Ignition Engine Using Elementary Reactions

    NASA Astrophysics Data System (ADS)

    Yamasaki, Yudai; Iida, Norimasa

    The present study focuses on clarifying the combustion mechanism of the homogeneous-charge compression-ignition (HCCI) engine in order to control ignition and combustion as well as to reduce HC and CO emissions and to maintain high combustion efficiency by calculating the chemical kinetics of elementary reactions. For the calculations, n-butane was selected as fuel since it is a fuel with the smallest carbon number in the alkane family that shows two-stage autoignition (heat release with low-temperature reaction (LTR) and with high-temperature reaction (HTR)) similarly to higher hydrocarbons such as gasoline. The CHEMKIN code was used for the calculations assuming zero dimensions in the combustion chamber and adiabatic change. The results reveal the heat release mechanism of the LTR and HTR, the control factor of ignition timing and combustion speed, and the condition need to reduce HC and CO emissions and to maintain high combustion efficiency.

  10. Report on Investigation of Alcohol Combustion Associated Wear in Spark Ignition Engines, Mechanisms and Lubricant Effects.

    DTIC Science & Technology

    1984-12-01

    investigated four - alcohol -containing fuels: pure methanol , pure ethanol, methanol in unleaded gaso- line, and ethanol in unleaded gasoline (gasohol...testing indicated that pure alcohol fuels reduced the buildup of engine .. deposits. Also neat methanol greatly increased engine wear rates at engine...results from reactions between methanol combustion products and the cast-iron cylinder liner, where the presence of liquid methanol in the combustion

  11. Extending Lean and EGR-Dilute Operating Limits of a Modern GDI Engine Using a Low Energy Transient Plasma Ignition System

    SciTech Connect

    Sevik, James; Wallner, Thomas; Pamminger, Michael; Scarcelli, Riccardo; Singleton, Dan; Sanders, Jason

    2016-11-01

    The efficiency improvement and emissions reduction potential of lean and exhaust gas recirculation (EGR)-dilute operation of spark-ignition gasoline engines is well understood and documented. However, dilute operation is generally limited by deteriorating combustion stability with increasing inert gas levels. The combustion stability decreases due to reduced mixture flame speeds resulting in significantly increased combustion initiation periods and burn durations. A study was designed and executed to evaluate the potential to extend lean and EGR-dilute limits using a low-energy transient plasma ignition system. The low-energy transient plasma was generated by nanosecond pulses and its performance compared to a conventional transistorized coil ignition (TCI) system operated on an automotive, gasoline direct-injection (GDI) single-cylinder research engine. The experimental assessment was focused on steady-state experiments at the part load condition of 1500 rpm 5.6 bar indicated mean effective pressure (IMEP), where dilution tolerance is particularly critical to improving efficiency and emission performance. Experimental results suggest that the energy delivery process of the low-energy transient plasma ignition system significantly improves part load dilution tolerance by reducing the early flame development period. Statistical analysis of relevant combustion metrics was performed in order to further investigate the effects of the advanced ignition system on combustion stability. Results confirm that at select operating conditions EGR tolerance and lean limit could be improved by as much as 20% (from 22.7 to 27.1% EGR) and nearly 10% (from λ = 1.55 to 1.7) with the low-energy transient plasma ignition system.

  12. EXTENDING LEAN AND EGR-DILUTE OPERATING LIMITS OF A MODERN GDI ENGINE USING A LOW-ENERGY TRANSIENT PLASMA IGNITION SYSTEM

    SciTech Connect

    Sevik, James Michael; Wallner, Thomas; Pamminger, Michael; Scarcelli, Riccardo; Singleton, Dan; Sanders, Jason

    2015-01-01

    The efficiency improvement and emissions reduction potential of lean and EGR dilute operation of spark-ignition gasoline engines is well understood and documented. However, dilute operation is generally limited by deteriorating combustion stability with increasing inert gas levels. The combustion stability decreases due to reduced mixture flame speeds resulting in significantly increased combustion initiation periods and burn durations. A study was designed and executed to evaluate the potential to extend lean and EGR-dilute limits using a low-energy transient plasma ignition system. The low-energy transient plasma was generated by nano-second pulses and its performance compared to a conventional transistorized coil ignition system operated on an automotive, gasoline direct injection (GDI) single-cylinder research engine. The experimental assessment was focused on steady-state experiments at the part load condition of 1500 rpm 5.6 bar IMEP, where dilution tolerance is particularly critical to improving efficiency and emissions performance. Experimental results suggest that the energy delivery process of the low-energy transient plasma ignition system significantly improves part load dilution tolerance by reducing the early flame development period. Statistical analysis of relevant combustion metrics was performed in order to further investigate the effects of the advanced ignition system on combustion stability. Results confirm that at select operating conditions EGR tolerance and lean limit could be improved by as much as 20% (from 22.7 to 27.1% EGR) and nearly 10% (from λ=1.55 to 1.7) with the low-energy transient plasma ignition system.

  13. Modeling Laser-Plasma Interactions at Direct-Drive Ignition-Relevant Plasma Conditions at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Solodov, A. A.; Rosenberg, M. J.; Myatt, J. F.; Epstein, R.; Seka, W.; Hohenberger, M.; Short, R. W.; Shaw, J. G.; Regan, S. P.; Froula, D. H.; Radha, P. B.; Bates, J. W.; Schmitt, A. J.; Michel, P.; Moody, J. D.; Ralph, J. E.; Turnbull, D. P.; Barrios, M. A.

    2016-10-01

    Laser-plasma interaction instabilities, such as two-plasmon decay (TPD) and stimulated Raman scattering (SRS), can be detrimental for direct-drive inertial confinement fusion because of target preheat by generated high-energy electrons. The radiation-hydrodynamics code DRACO has been used to design planar-target experiments that generate plasma and interaction conditions relevant to direct-drive-ignition designs (IL 1015 W / cm 2 , Te > 3 KeV density gradient scale lengths of Ln 600 μm) . The hot-electron temperature of 40to50keV and the fraction of laser energy converted to hot electrons of 0.5to were inferred based on comparing the simulated and experimentally observed x-ray emission when the laser intensity at the quarter-critical surface increased from 6 to 15 ×1014 W / cm 2 . The measured SRS energy was sufficient to explain the observed total energy in hot electrons. Implications for ignition-scale direct-drive experiments and hot-electron preheat mitigation using mid- Z ablators will be discussed. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  14. Mathematical modeling of forest canopy ignition by the Tunguska meteorite with allowance for the dual temperature of the medium

    SciTech Connect

    Grishin, A.M.; Perminov, V.A. )

    1992-12-01

    The ignition of the forest canopy during the Tunguska event is examined by using a mathematical model of forest fires. The dimensions of the ignition zone for fixed explosion energies are determined for different parameters of the forest canopy. Based on mathematical experiments, the explosion energy that agrees best with the available data is determined. The temperature fields and the velocities and concentrations of the gas phase components are determined for different points in time. 8 refs.

  15. Impact of Fire Resistant Fuel Blends on Compression Ignition Engine Performance

    DTIC Science & Technology

    2011-07-01

    mass flowrate system and logged with PRISM.  Inlet air is drawn in from the building ventilation system at ambient conditions.  Engine exhaust is...exhaust backpressure.  Emissions are sampled from an exhaust probe installed between the engine and exhaust system butterfly valve.  Crankcase

  16. Fabrication and testing of an enhanced ignition system to reduce cold-start emissions in an ethanol (E85) light-duty truck engine

    SciTech Connect

    Gardiner, D; Mallory, R; Todesco, M

    1997-09-01

    This report describes an experimental investigation of the potential for an enhanced ignition system to lower the cold-start emissions of a light-duty vehicle engine using fuel ethanol (commonly referred to as E85). Plasma jet ignition and conventional inductive ignition were compared for a General Motors 4-cylinder, alcohol-compatible engine. Emission and combustion stability measurements were made over a range of air/fuel ratios and spark timing settings using a steady-state, cold-idle experimental technique in which the engine coolant was maintained at 25 C to simulate cold-running conditions. These tests were aimed at identifying the degree to which calibration strategies such as mixture enleanment and retarded spark timing could lower engine-out hydrocarbon emissions and raise exhaust temperatures, as well as determining how such calibration changes would affect the combustion stability of the engine (as quantified by the coefficient of variation, or COV, of indicated mean effective pressure calculated from successive cylinder pressure measurements). 44 refs., 39 figs.

  17. CARS temperature measurements and the cyclic dispersion of knock in spark ignition engines

    SciTech Connect

    Bradley, D. |; Kalghatgi, G.T.; Morley, C.; Snowdon, P.; Yeo, J.

    1994-12-31

    The use is described of the coherent anti-Stokes Raman spectroscopy (CARS) technique in a single-cylinder research engine to measure end-gas temperature in the regime that leads to the onset of knock. The investigations, under nominally the same running conditions, covered a large cyclic dispersion of knock, with knock occurring in about 80% of the cycles. In-cylinder pressures were measured with a transducer, and an ion gap signified flame arrival towards the end of the flame travel and just before autoignition. In general, the temperature increased by over 100 K, both with and without knock, as a result of exothermic preflame reactions. This measured elevation was supported by computations with a simple five-step model of autoignition, calibrated against measured autoignition times in a rapid compression machine. The temperatures measured just prior to knock increased with the severity of the knock. The observed severe cyclic dispersion of knock, under the conditions of the study, is attributed primarily to the cyclic dispersion of flame speeds. An increase in flame speed is associated with an increase in temperature and greater propensity to knock.

  18. Performance and Emission Characteristics of a Compression Ignition Engine Operating on Blends of Castor Oil Biodiesel-Diesel

    NASA Astrophysics Data System (ADS)

    Kanwar, Roopesh; Sharma, Pushpendra Kumar; Singh, Aditya Narayan; Agrawal, Yadvendra Kumar

    2016-06-01

    Diesel vehicles are the nerves and veins of transportation, particularly in developing countries. With the rapid rate of modernization, increasing demand of fuel is inevitable. The exponential increase in fuel prices and the scarcity of its supply from the environment have promoted interest in the development of alternative sources of fuel. In this work, genus Ricinus communis L. was studied in order to delimit their potential as a raw material for biodiesel production. Further, castor oil, ethyl ester were prepared by transesterification using potassium hydroxide (KOH) as a catalyst and tested on a four-stroke, single-cylinder compression ignition engine. The test was carried out at a constant speed of 3000 rpm at different loads. The results represent a substantial decrease in carbon monoxide (CO) emission with an increasing biodiesel percentage. The reduction of CO in B05, B10, B15 and B20 averaged 11.75, 22.02, 24.23 and 28.79 %, respectively, compared to mineral diesel. The emission results of the comparative test indicated that CO, oxygen (O2) and smoke density emissions are found to be lower when the engine is filled with B05, B10, B15 and B20 as compared to mineral diesel, while carbon dioxide (CO2) and nitrogen oxide (NOx) with B05, B10, B15 and B20 are found to increase marginally. Brake thermal efficiency and brake specific fuel consumption decrease and increase respectively in biodiesel with different blends in comparison of mineral diesel.

  19. Performance and Emission Characteristics of a Compression Ignition Engine Operating on Blends of Castor Oil Biodiesel-Diesel

    NASA Astrophysics Data System (ADS)

    Kanwar, Roopesh; Sharma, Pushpendra Kumar; Singh, Aditya Narayan; Agrawal, Yadvendra Kumar

    2017-04-01

    Diesel vehicles are the nerves and veins of transportation, particularly in developing countries. With the rapid rate of modernization, increasing demand of fuel is inevitable. The exponential increase in fuel prices and the scarcity of its supply from the environment have promoted interest in the development of alternative sources of fuel. In this work, genus Ricinus communis L. was studied in order to delimit their potential as a raw material for biodiesel production. Further, castor oil, ethyl ester were prepared by transesterification using potassium hydroxide (KOH) as a catalyst and tested on a four-stroke, single-cylinder compression ignition engine. The test was carried out at a constant speed of 3000 rpm at different loads. The results represent a substantial decrease in carbon monoxide (CO) emission with an increasing biodiesel percentage. The reduction of CO in B05, B10, B15 and B20 averaged 11.75, 22.02, 24.23 and 28.79 %, respectively, compared to mineral diesel. The emission results of the comparative test indicated that CO, oxygen (O2) and smoke density emissions are found to be lower when the engine is filled with B05, B10, B15 and B20 as compared to mineral diesel, while carbon dioxide (CO2) and nitrogen oxide (NOx) with B05, B10, B15 and B20 are found to increase marginally. Brake thermal efficiency and brake specific fuel consumption decrease and increase respectively in biodiesel with different blends in comparison of mineral diesel.

  20. Modeling risk of ignition as a function of landscape and human presence using satellite observations

    NASA Astrophysics Data System (ADS)

    Loboda, T. V.; Hight-Harf, C.; French, N. H.

    2012-12-01

    Wildland fire is an integral component of many ecosystems worldwide. However, relatively little is known about the patterns of fire ignitions as a function of landscape and how they influence regional fire occurrence. Conventional methods of identifying the patterns of ignition are limited especially in areas where field-based data are not available. Satellite observations of fire activity from the Moderate Resolution Imaging Spectroradiometer (MODIS) now provide a 12-year record of fire activity globally. In this study we show how Fire Spread Reconstruction approach is applied to the MODIS active fire detections to analyze the spatial patterns and drivers of fire ignition in three different ecoregions: 1) boreal forests the Russian Far East (RFE), 2) Mediterranean ecosystems of Southern California, and 3) North American tundra. The resultant spatio-temporal patterns are used to develop a Risk of Ignition (ROI) coefficient within the Fire Occurrence modeling framework. Our results show pronounced differences in the spatial patterns of the ROI between the three regions. Only in tundra's remote and unpopulated regions temporal patterns of ROI coincide with the known patterns of fire occurrence and spread. In Southern California and the RFE ROI is more closely linked to spatial and temporal patterns of human activity on the landscape and thus does not correlate well with seasons when large burns occur. Fig. 1 shows the spatial and temporal distribution of ROI in the Russian Far East. The success rate of this method is limited by the amount of observations and fire occurrence within the ecosystems of interest: ROI is established with higher accuracy in the RFE for a single month of April when more than 4000 individual fire events were observed between 2001 and 2010. In tundra and in the winter months within the RFE, where relative amount of fire occurrence is low, the results are less robust. However, the accuracy of the ROI modeling will grow as the MODIS era

  1. An analysis of a highly compounded two-stroke-cycle compression-ignition engine

    NASA Technical Reports Server (NTRS)

    Tauschek, Max J; Sather, Bernard I; Biermann, Arnold E

    1949-01-01

    Presents an analysis of a compound engine operating with manifold pressures ranging from 60 to 110 lb/sq in. absolute. The effects of engine limits (peak cylinder pressure and turbine-inlet temperature) and component efficiency are discussed. A range analysis is used to evaluate the merit of the engine. The analysis indicates that specific-fuel-consumption values of 0.32 lb/bhp-hr and specific weights of 0.8 lb/bhp are obtainable at high manifold pressures.

  2. Modeling of laser-induced damage and optic usage at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Liao, Zhi M.; Nostrand, Mike; Carr, Wren; Bude, Jeff; Suratwala, Tayyab I.

    2016-07-01

    Modeling of laser-induced optics damage has been introduced to benchmark existing optic usage at the National Ignition Facility (NIF) which includes the number of optics exchanged for damage repair. NIF has pioneered an optics recycle strategy to allow it to run the laser at capacity since fully commissioned in 2009 while keeping the cost of optics usage manageable. We will show how the damage model is being used to evaluate strategies to streamline our optics loop efficiency, as we strive to increase the laser shot rate without increasing operating costs.

  3. Heavy-Duty Stoichiometric Compression Ignition Engine with Improved Fuel Economy over Alternative Technologies for Meeting 2010 On-Highway Emission

    SciTech Connect

    Kirby J. Baumgard; Richard E. Winsor

    2009-12-31

    The objectives of the reported work were: to apply the stoichiometric compression ignition (SCI) concept to a 9.0 liter diesel engine; to obtain engine-out NO{sub x} and PM exhaust emissions so that the engine can meet 2010 on-highway emission standards by applying a three-way catalyst for NO{sub x} control and a particulate filter for PM control; and to simulate an optimize the engine and air system to approach 50% thermal efficiency using variable valve actuation and electric turbo compounding. The work demonstrated that an advanced diesel engine can be operated at stoichiometric conditions with reasonable particulate and NOx emissions at full power and peak torque conditions; calculated that the SCI engine will operate at 42% brake thermal efficiency without advanced hardware, turbocompounding, or waste heat recovery; and determined that EGR is not necessary for this advanced concept engine, and this greatly simplifies the concept.

  4. Microstructural Effects on the Ignition Behavior of Various HMX Materials

    NASA Astrophysics Data System (ADS)

    Welle, Eric

    2013-06-01

    The detonation physics community has embraced the idea that initiation of high explosives proceeds from an ignition event through subsequent growth to steady detonation. This construct is the basis for the well-known Lee-Tarver reactive flow model. A weakness of all the commonly used ignition and growth models is that microstructural characteristics are not explicitly incorporated in their ignition terms. This is the case in spite of a demonstrated, but not well-understood, empirical link between morphology and initiation of energetic materials. Morphological effects have been parametrically studied in many ways, with the majority of efforts focused on establishing a tie between bulk powder metrics and ignition of the consolidated material. More recently, there has been a shift toward characterizing the microstructure of consolidated materials in order to understand the underlying mechanisms governing performance. We have assessed the utility of using the James' Ignition model as a tool to quantify effects of bed microstructure on ignition behavior. We have studied the ignition behavior of four types of HMX materials ranging from fine particle fluid energy milled to course particle material. We will also report characterization of the pressed microstructure of each of the various materials and discuss how the measured ignition behavior may have been influenced. DISTRIBUTION A. Approved for public release, distribution unlimited. (96ABW-2013-0063) R.R. Wixom, Sandia National Laboratories/Explosives Technologies Group; C. Molek, Air Force Research Laboratory/Munitions Directorate; and P. Samuels, Army Research Development and Engineering Center/Picatinny Arsenal.

  5. Twin engine afterbody model

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    1994-01-01

    This test was originally conducted to determine the effects of several empennage and afterbody parameters on the aft-end aerodynamic characteristics of a twin-engine fighter-type configuration. Model variables were as follows: horizontal tail axial location and incidence, vertical tail axial location and configuration (twin-vs single-tail arrangements), tail booms, and nozzle power setting. Jet propulsion was simulated by exhausting high-pressure, cold-flow air from the nozzles. Following a successful test conducted on a single engine nacelle model to validate a CFD code, this model was chosen to be instrumented with pressure taps on the afterbody and nozzles and used as a follow-on test, providing a more complex geometry for the CFD code validation. A more limited test matrix was run to collect the pressure data, employing only the twin-tail configuration and varying only the horizontal and vertical tail locations. Mach number was varied from 0.6 to 1.2. Nozzle pressure ratio was varied from jet-off to 8. Angle-of-attack varied from 0 to 8 deg.

  6. TOPICAL REVIEW: Plasma assisted ignition and combustion

    NASA Astrophysics Data System (ADS)

    Starikovskaia, S. M.

    2006-08-01

    In recent decades particular interest in applications of nonequilibrium plasma for the problems of plasma-assisted ignition and plasma-assisted combustion has been observed. A great amount of experimental data has been accumulated during this period which provided the grounds for using low temperature plasma of nonequilibrium gas discharges for a number of applications at conditions of high speed flows and also at conditions similar to automotive engines. The paper is aimed at reviewing the data obtained and discusses their treatment. Basic possibilities of low temperature plasma to ignite gas mixtures are evaluated and historical references highlighting pioneering works in the area are presented. The first part of the review discusses plasmas applied to plasma-assisted ignition and combustion. The paper pays special attention to experimental and theoretical analysis of some plasma parameters, such as reduced electric field, electron density and energy branching for different gas discharges. Streamers, pulsed nanosecond discharges, dielectric barrier discharges, radio frequency discharges and atmospheric pressure glow discharges are considered. The second part depicts applications of discharges to reduce the ignition delay time of combustible mixtures, to ignite transonic and supersonic flows, to intensify ignition and to sustain combustion of lean mixtures. The results obtained by different authors are cited, and ways of numerical modelling are discussed. Finally, the paper draws some conclusions on the main achievements and prospects of future investigations in the field.

  7. Active flow control for maximizing performance of spark ignited stratified charge engines. Final report

    SciTech Connect

    Fedewa, Andrew; Stuecken, Tom; Timm, Edward; Schock, Harold J.; Shih, Tom-I.P.; Koochesfahani, Manooch; Brereton, Giles

    2002-10-15

    Reducing the cycle-to-cycle variability present in stratified-charge engines is an important step in the process of increasing their efficiency. As a result of this cycle-to-cycle variability, fuel injection systems are calibrated to inject more fuel than necessary, in an attempt to ensure that the engines fire on every cycle. When the cycle-to-cycle variability is lowered, the variation of work per cycle is reduced and the lean operating limit decreases, resulting in increased fuel economy. In this study an active flow control device is used to excite the intake flow of an engine at various frequencies. The goal of this excitation is to control the way in which vortices shed off of the intake valve, thus lowering the cycle-to-cycle variability in the flow field. This method of controlling flow is investigated through the use of three engines. The results of this study show that the active flow control device did help to lower the cycle-to-cycle variability of the in-cylinder flow field; however, the reduction did not translate directly into improved engine performance.

  8. Quantitative Analysis of Mixture Preparation Processes in New Direct-Injection Spark Ignition Engines

    NASA Astrophysics Data System (ADS)

    Itoh, Teruyuki; Kakuho, Akihiko; Hiraya, Koji; Takahashi, Eiji; Urushihara, Tomonori

    Visualization plays an effective role in the establishment of a new combustion concept by helping to find the optimal results quickly among many different parameters and contributing to a shorter development period. Laser-induced fluorescence, Raman scattering and infrared absorption were used to measure the air/fuel ratio quantitatively in a third-generation direct-injection gasoline (DIG) engine with a spray-guided mixture formation process and comparisons were made with the mixture formation concepts of the first- and second-generation DIG engines. The optimum combination of fuel spray, gas flow and combustion chamber configuration was found to be different for the three generations of DIG engines. The characteristics of the stable combustion region for obtaining higher thermal efficiency and cleaner exhaust emissions differed among the three mixture formation concepts.

  9. Studies on exhaust emissions of mahua oil operated compression ignition engine.

    PubMed

    Kapilan, N; Reddy, R P

    2009-07-01

    The world is confronted with fossil fuel depletion and environmental degradation. The energy demand and pollution problems lead to research for an alternative renewable energy sources. Vegetable oils and biodiesel present a very promising alternative fuel to diesel. In this work, an experimental work was carried out to study the feasibility of using raw mahua oil (MO) as a substitute for diesel in dual fuel engine. A single cylinder diesel engine was modified to work in dual fuel mode and liquefied petroleum gas (LPG) was used as primary fuel and mahua oil was used as pilot fuel. The results show that the performance of the dual fuel engine at the injector opening pressure of 220 bar and the advanced injection timing of 30 degrees bTDC results in performance close to diesel base line (DBL) operation and lower smoke and oxides of nitrogen emission.

  10. Emissions and new technology programs for conventional spark-ignition aircraft engines

    NASA Technical Reports Server (NTRS)

    Wintucky, W. T.

    1976-01-01

    A long-range technology plan in support of general aviation engines was formulated and is being implemented at the Lewis Research Center. The overall program was described, and that part of the program that represents the in-house effort at Lewis was presented in detail. Three areas of government and industry effort involving conventional general-aviation piston engines were part of a coordinated overall plan: (1) FAA/NASA joint program, (2) NASA contract exhaust emissions pollution reduction program, and (3) NASA in-house emissions reduction and new technology program.

  11. Understanding the ignition mechanism of high-pressure spray flames

    SciTech Connect

    Dahms, Rainer N.; Paczko, Günter A.; Skeen, Scott A.; Pickett, Lyle M.

    2016-10-25

    A conceptual model for turbulent ignition in high-pressure spray flames is presented. The model is motivated by first-principles simulations and optical diagnostics applied to the Sandia n-dodecane experiment. The Lagrangian flamelet equations are combined with full LLNL kinetics (2755 species; 11,173 reactions) to resolve all time and length scales and chemical pathways of the ignition process at engine-relevant pressures and turbulence intensities unattainable using classic DNS. The first-principles value of the flamelet equations is established by a novel chemical explosive mode-diffusion time scale analysis of the fully-coupled chemical and turbulent time scales. Contrary to conventional wisdom, this analysis reveals that the high Damköhler number limit, a key requirement for the validity of the flamelet derivation from the reactive Navier–Stokes equations, applies during the entire ignition process. Corroborating Rayleigh-scattering and formaldehyde PLIF with simultaneous schlieren imaging of mixing and combustion are presented. Our combined analysis establishes a characteristic temporal evolution of the ignition process. First, a localized first-stage ignition event consistently occurs in highest temperature mixture regions. This initiates, owed to the intense scalar dissipation, a turbulent cool flame wave propagating from this ignition spot through the entire flow field. This wave significantly decreases the ignition delay of lower temperature mixture regions in comparison to their homogeneous reference. This explains the experimentally observed formaldehyde formation across the entire spray head prior to high-temperature ignition which consistently occurs first in a broad range of rich mixture regions. There, the combination of first-stage ignition delay, shortened by the cool flame wave, and the subsequent delay until second-stage ignition becomes minimal. A turbulent flame subsequently propagates rapidly through the entire mixture over time scales

  12. Microgravity ignition experiment

    NASA Technical Reports Server (NTRS)

    Motevalli, Vahid; Elliott, William; Garrant, Keith; Marcotte, Ryan

    1992-01-01

    The purpose of this project is to develop a flight-ready apparatus of the microgravity ignition experiment for the GASCAN 2 program. The microgravity ignition experiment is designed to study how a microgravity environment affects the time to ignition of a sample of alpha-cellulose paper. A microgravity environment will result in a decrease in the heat transferred from the sample due to a lack of convection currents, which would decrease time to ignition. A lack of convection current would also cause the oxygen supply at the sample not to be renewed, which could delay or even prevent ignition. When this experiment is conducted aboard GASCAN 2, the dominant result of the lack of ignition will be determined. The experiment consists of four canisters containing four thermocouples and a sensor to detect ignition of the paper sample. This year the interior of the canister was redesigned and a mathematical model of the heat transfer around the sample was developed. This heat transfer model predicts an ignition time of approximately 5.5 seconds if the decrease of heat loss from the sample is the dominant factor of the lack of convection currents.

  13. A High-Resolution Integrated Model of the National Ignition Campaign Cryogenic Layered Experiments

    DOE PAGES

    Jones, O. S.; Callahan, D. A.; Cerjan, C. J.; ...

    2012-05-29

    A detailed simulation-based model of the June 2011 National Ignition Campaign (NIC) cryogenic DT experiments is presented. The model is based on integrated hohlraum-capsule simulations that utilize the best available models for the hohlraum wall, ablator, and DT equations of state and opacities. The calculated radiation drive was adjusted by changing the input laser power to match the experimentally measured shock speeds, shock merger times, peak implosion velocity, and bangtime. The crossbeam energy transfer model was tuned to match the measured time-dependent symmetry. Mid-mode mix was included by directly modeling the ablator and ice surface perturbations up to mode 60.more » Simulated experimental values were extracted from the simulation and compared against the experiment. The model adjustments brought much of the simulated data into closer agreement with the experiment, with the notable exception of the measured yields, which were 15-40% of the calculated yields.« less

  14. Investigation of a Spark Ignition Internal Combustion Engine via IR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sakai, Stephen; White, Allen R.; Gross, Kevin; Devasher, Rebecca B.

    2010-06-01

    Previous work has shown that the automotive fuel components of isopropanoland ethanol can be excited by a 10.2 um and 9.3 um CO2 lasers, respectively. Through the use of a monochromator and an indium antimonide detector, the decay time of the excited molecules was measured and found to be significantly long enough to allow for the possibility of experimentation in an internal combustion (IC) engine. In order to pursue In Situ measurements in an internal combustion engine, a MegaTech Mark III transparent engine was modified with a sapphire combustion chamber. This modification will allow the transmission of infrared radiation for time-resolved spectroscopic measurements by an infrared spectrometer. By using a Telops FIRST-MWE imaging Fourier transform spectrometer, temporally and spatially resolved infrared spectral data can be acquired and compared for combustion in the engine both with and without laser excitation. Measurements performed with system provide insight into the energy transfer vectors that precede combustion as well as provide an in situ measurement of the progress of combustion.

  15. Modeling of hybrid vehicle fuel economy and fuel engine efficiency

    NASA Astrophysics Data System (ADS)

    Wu, Wei

    "Near-CV" (i.e., near-conventional vehicle) hybrid vehicles, with an internal combustion engine, and a supplementary storage with low-weight, low-energy but high-power capacity, are analyzed. This design avoids the shortcoming of the "near-EV" and the "dual-mode" hybrid vehicles that need a large energy storage system (in terms of energy capacity and weight). The small storage is used to optimize engine energy management and can provide power when needed. The energy advantage of the "near-CV" design is to reduce reliance on the engine at low power, to enable regenerative braking, and to provide good performance with a small engine. The fuel consumption of internal combustion engines, which might be applied to hybrid vehicles, is analyzed by building simple analytical models that reflect the engines' energy loss characteristics. Both diesel and gasoline engines are modeled. The simple analytical models describe engine fuel consumption at any speed and load point by describing the engine's indicated efficiency and friction. The engine's indicated efficiency and heat loss are described in terms of several easy-to-obtain engine parameters, e.g., compression ratio, displacement, bore and stroke. Engine friction is described in terms of parameters obtained by fitting available fuel measurements on several diesel and spark-ignition engines. The engine models developed are shown to conform closely to experimental fuel consumption and motored friction data. A model of the energy use of "near-CV" hybrid vehicles with different storage mechanism is created, based on simple algebraic description of the components. With powertrain downsizing and hybridization, a "near-CV" hybrid vehicle can obtain a factor of approximately two in overall fuel efficiency (mpg) improvement, without considering reductions in the vehicle load.

  16. Particulate Matter Sampling and Volatile Organic Compound Removal for Characterization of Spark Ignited Direct Injection Engine Emissions

    SciTech Connect

    Matthias, Nick; Farron, Carrie; Foster, David E.; Andrie, Mike; Krieger, Roger; Najt, Paul; Narayanaswamy, Kushal; Solomon, Arun; Zelenyuk, Alla

    2012-01-01

    More stringent emissions regulations are continually being proposed to mitigate adverse human health and environmental impacts of internal combustion. With that in mind, it has been proposed that vehicular particulate matter (PM) emissions should be regulated based on particle number in addition to particle mass. One aspect of this project is to study different sample handling methods for number based aerosol measurements, specifically, two different methods for removing volatile organic compounds (VOCs) from an aerosol sample. One method is a Dekati Thermodenuder (TD) and the other is an evaporative chamber/diluter (EvCh). These sample handling methods have been implemented for this project in an engine test cell built around a direct injection spark ignited (DISI) engine. The engine was designed for stoichiometric, homogeneous combustion. Direct injection is of particular interest for improved fuel efficiency but this comes with the production of a significant amount of (PM) and may therefore be subject to the proposed number based regulation. Another aspect of this project is to characterize PM from this engine in terms of particle number and composition. The first interesting observation is that PM number distributions, acquired using a TSI SMPS, have a large accumulation mode (30-294 nm) but a very small nuclei mode (8-30 nm). This is understood to represent a lack of condensation particles meaning that neither the exhaust conditions nor the sample handling conditions are conducive to condensation. This lack of nuclei mode does not, however, represent a lack of VOCs in the sample. It has been observed, using mass spectral analysis (limited to PM>50 nm), that PM from the DISI engine has approximately 40% organic content through varying operating conditions. This begs the question of how effective different sample handling methods are at removing these VOCs. For one specific operating condition, called Cold Start, the un-treated PM was 40% organic. The TD

  17. Advanced aircraft ignition CRADA final report

    SciTech Connect

    Early, J.W.

    1997-03-01

    Conventional commercial and military turbo-jet aircraft engines use capacitive discharge ignition systems to initiate fuel combustion. The fuel-rich conditions required to ensure engine re-ignition during flight yield less than optimal engine performance, which in turn reduces fuel economy and generates considerable pollution in the exhaust. Los Alamos investigated two approaches to advanced ignition: laser based and microwave based. The laser based approach is fuel ignition via laser-spark breakdown and via photo-dissociation of fuel hydrocarbons and oxygen. The microwave approach involves modeling, and if necessary redesigning, a combustor shape to form a low-Q microwave cavity, which will ensure microwave breakdown of the air/fuel mixture just ahead of the nozzle with or without a catalyst coating. This approach will also conduct radio-frequency (RF) heating of ceramic elements that have large loss tangents. Replacing conventional systems with either of these two new systems should yield combustion in leaner jet fuel/air mixtures. As a result, the aircraft would operate with (1) considerable less exhaust pollution, (2) lower engine maintenance, and (3) significantly higher fuel economy.

  18. A novel miniaturized passively Q-switched pulse-burst laser for engine ignition.

    PubMed

    Ma, Yufei; Li, Xudong; Yu, Xin; Fan, Rongwei; Yan, Renpeng; Peng, Jiangbo; Xu, Xinrui; Sun, Rui; Chen, Deying

    2014-10-06

    A novel miniaturized Cr⁴⁺:YAG passively Q-switched Nd:YAG pulse-burst laser under 808 nm diode-laser pulse-pumping was demonstrated for the purpose of laser-induced plasma ignition, in which pulse-burst mode can realize both high repetition rate and high pulse energy simultaneously in a short period. Side-pumping configuration and two different types of laser cavities were employed. The pumping pulse width was constant at 250 μs. For the plane-plane cavity, the output beam profile was flat-top Gaussian and the measured M² value was 4.1 at the maximum incident pump energy of 600 mJ. The pulse-burst laser contained a maximum of 8 pulses, 7 pulses and 6 pulses for pulse-burst repetition rate of 10 Hz, 50 Hz and 100 Hz, respectively. The energy obtained was 15.5 mJ, 14.9 mJ and 13.9 mJ per pulse for pulse-burst repetition rate of 10 Hz, 50 Hz and 100 Hz, respectively. The maximum repetition rate of laser pulses in pulse-burst was 34.6 kHz for 8 pulses at the incident pump energy of 600 mJ and the single pulse width was 13.3 ns. The thermal lensing effect of Nd:YAG rod was investigated, and an plane-convex cavity was adopted to compensate the thermal lensing effect of Nd:YAG rod and improve the mode matching. For the plane-convex cavity, the output beam profile was quasi-Gaussian and the measured M2 value was 2.2 at the incident pump energy of 600 mJ. The output energy was 10.6 mJ per pulse for pulse-burst repetition rate of 100 Hz. The maximum repetition rate of laser pulses in pulse-burst was 27.4 kHz for 6 pulses at the incident pump energy of 600 mJ and the single pulse width was 14.2 ns. The experimental results showed that this pulse-burst laser can produce high repetition rate (>20 kHz) and high pulse energy (>10 mJ) simultaneously in a short period for both two different cavities.

  19. Application of a four-step HMX kinetic model to an impact-induced fraction ignition problems

    SciTech Connect

    Perry, William L; Gunderson, Jake A; Dickson, Peter M

    2010-01-01

    There has been a long history of interest in the decomposition kinetics of HMX and HMX-based formulations due to the widespread use of this explosive in high performance systems. The kinetics allow us to predict, or attempt to predict, the behavior of the explosive when subjected to thermal hazard scenarios that lead to ignition via impact, spark, friction or external heat. The latter, commonly referred to as 'cook off', has been widely studied and contemporary kinetic and transport models accurately predict time and location of ignition for simple geometries. However, there has been relatively little attention given to the problem of localized ignition that results from the first three ignition sources of impact, spark and friction. The use of a zero-order single-rate expression describing the exothermic decomposition of explosives dates to the early work of Frank-Kamanetskii in the late 1930s and continued through the 60's and 70's. This expression provides very general qualitative insight, but cannot provide accurate spatial or timing details of slow cook off ignition. In the 70s, Catalano, et al., noted that single step kinetics would not accurately predict time to ignition in the one-dimensional time to explosion apparatus (ODTX). In the early 80s, Tarver and McGuire published their well-known three step kinetic expression that included an endothermic decomposition step. This scheme significantly improved the accuracy of ignition time prediction for the ODTX. However, the Tarver/McGuire model could not produce the internal temperature profiles observed in the small-scale radial experiments nor could it accurately predict the location of ignition. Those factors are suspected to significantly affect the post-ignition behavior and better models were needed. Brill, et al. noted that the enthalpy change due to the beta-delta crystal phase transition was similar to the assumed endothermic decomposition step in the Tarver/McGuire model. Henson, et al., deduced the

  20. Fire in a Changing Climate: Stochastic versus Threshold-constrained Ignitions in a Dynamic Global Vegetation Model

    NASA Astrophysics Data System (ADS)

    Sheehan, T.; Bachelet, D. M.; Ferschweiler, K.

    2015-12-01

    The MC2 dynamic global vegetation model fire module simulates fire occurrence, area burned, and fire impacts including mortality, biomass burned, and nitrogen volatilization. Fire occurrence is based on fuel load levels and vegetation-specific thresholds for three calculated fire weather indices: fine fuel moisture code (FFMC) for the moisture content of fine fuels; build-up index (BUI) for the total amount of fuel available for combustion; and energy release component (ERC) for the total energy available to fire. Ignitions are assumed (i.e. the probability of an ignition source is 1). The model is run with gridded inputs and the fraction of each grid cell burned is limited by a vegetation-specific fire return period (FRP) and the number of years since the last fire occurred in the grid cell. One consequence of assumed ignitions FRP constraint is that similar fire behavior can take place over large areas with identical vegetation type. In regions where thresholds are often exceeded, fires occur frequently (annually in some instances) with a very low fraction of a cell burned. In areas where fire is infrequent, a single hot, dry climate event can result in intense fire over a large region. Both cases can potentially result in large areas with uniform vegetation type and age. To better reflect realistic fire occurrence, we have developed a stochastic fire occurrence model that: a) uses a map of relative ignition probability and a multiplier to alter overall ignition occurrence; b) adjusts the original fixed fire thresholds with ignition success probabilities based on fire weather indices; and c) calculates spread by using a probability based on slope and wind direction. A Monte Carlo method is used with all three algorithms to determine occurrence. The new stochastic ignition approach yields more variety in fire intensity, a smaller annual total of cells burned, and patchier vegetation.

  1. Fractal approach to the evaluation of burning rates in the vicinity of the piston in a spark-ignition engine

    SciTech Connect

    Foucher, F.; Mounaim-Rousselle, C.

    2005-11-01

    The burning rate in the vicinity of a piston is estimated from a fractal analysis. The fractal parameters are determined from laser sheet tomography flame images for methane-air mixtures with three equivalence ratios (1, 0.9, 0.8) in a transparent spark-ignition engine. Two imaging configurations were used: five horizontal planes placed at different distances from the piston (0, 1, 2, 3, and 5 mm) and a vertical one passed through the center of the combustion chamber. The methodology proposed by Foucher et al. [F. Foucher, S. Burnel, C. Mounaim-Rousselle, Proc. Combust. Inst. 29 (2002) 751-757] allows the effect of cyclic variations to be avoided. The fractal formulation is modified to take into account the flame-piston distance and flame quenching. Far from the piston, evolution of the fractal dimension versus q{sup '}/S{sub L}{sup 0} is found to be in good agreement with literature results. Near the piston, the fractal dimension evolves significantly when the distance is about twice the integral length scale and tends toward 2, the fractal dimension of a laminar flame front. The quenching ratio parameter Q{sub R} is introduced to consider the quenching of the flame by the piston. Finally, the burning rate is determined as a function of the distance between the wall and the mean flame contour and compared to a flame density approach, and similar results are found.

  2. THREE-DIMENSIONAL IGNITION AND GROWTH REACTIVE FLOW MODELING OF PRISM FAILURE TESTS ON PBX 9502

    SciTech Connect

    Garcia, M L; Tarver, C M

    2006-06-20

    The Ignition and Growth reactive flow model for shock initiation and detonation of solid explosives based on triaminotirnitrobenzene (TATB) is applied to three-dimensional detonation wave propagation. The most comprehensive set of three-dimensional detonation wave propagation data is that measured using the trapezoidal prism test. In this test, a PBX 9501 (95% HMX, 2.5% Estane, and 2.5% BDNPA/F) line detonator initiates a detonation wave along the trapezoidal face of a PBX 9502 (95% TATB and 5% Kel-F binder) prism. The failure thickness, which has been shown experimentally to be roughly half of the failure diameter of a long cylindrical charge, is measured after 50 mm of detonation wave propagation by impact with an aluminum witness plate. The effects of confinement impedance on the PBX 9502 failure thickness have been measured using air (unconfined), water, PMMA, magnesium, aluminum, lead, and copper placed in contact with the rectangular faces of the prism parallel to the direction of detonation propagation. These prism test results are modeled using the two-dimensional PBX 9502 Ignition and Growth model parameters determined by calculating failure diameter and tested on recent corner turning experiments. Good agreement between experimentally measured and calculated prism failure thicknesses for unconfined and confined PBX 9502 is reported.

  3. Modeling down-scattered neutron images from cryogenic fuel implosions at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Raman, Kumar; Casey, Dan; Callahan, Debra; Clark, Dan; Fittinghoff, David; Grim, Gary; Hatchett, Steve; Hinkel, Denise; Jones, Ogden; Kritcher, Andrea; Seek, Scott; Suter, Larry; Merrill, Frank; Wilson, Doug

    2016-10-01

    In experiments with cryogenic deuterium-tritium (DT) fuel layers at the National Ignition Facility (NIF), an important technique for visualizing the stagnated fuel assembly is to image the 6-12 MeV neutrons created by scatters of the 14 MeV hotspot neutrons in the surrounding cold fuel. However, such down-scattered neutron images are difficult to interpret without a model of the fuel assembly, because of the nontrivial neutron kinematics involved in forming the images. For example, the dominant scattering modes are at angles other than forward scattering and the 14 MeV neutron fluence is not uniform. Therefore, the intensity patterns in these images usually do not correspond in a simple way to patterns in the fuel distribution, even for simple fuel distributions. We describe our efforts to model synthetic images from ICF design simulations with data from the National Ignition Campaign and after. We discuss the insight this gives, both to understand how well the models are predicting fuel asymmetries and to inform how to optimize the diagnostic for the types of fuel distributions being predicted. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  4. Combustion parameters of spark ignition engine using waste potato bioethanol and gasoline blended fuels

    NASA Astrophysics Data System (ADS)

    Ghobadian, B.; Najafi, G.; Abasian, M.; Mamat, R.

    2015-12-01

    The purpose of this study is to investigate the combustion parameters of a SI engine operating on bioethanol-gasoline blends (E0-E20: 20% bioethanol and 80% gasoline by volume). A reactor was designed, fabricated and evaluated for bioethanol production from potato wastes. The results showed that increasing the bioethanol content in the blend fuel will decrease the heating value of the blended fuel and increase the octane number. Combustion parameters were evaluated and analyzed at different engine speeds and loads (1000-5000 rpm). The results revealed that using bioethanol-gasoline blended fuels will increase the cylinder pressure and its 1st and 2nd derivatives (P(θ), P•(θ) and P••(θ)). Moreover, using bioethanol- gasoline blends will increase the heat release (Q•(θ)) and worked of the cycle. This improvement was due to the high oxygen percentage in the ethanol.

  5. Experimental Study of Ignition by Hot Spot in Internal Combustion Engines

    NASA Technical Reports Server (NTRS)

    Serruys, Max

    1938-01-01

    In order to carry out the contemplated study, it was first necessary to provide hot spots in the combustion chamber, which could be measured and whose temperature could be changed. It seemed difficult to realize both conditions working solely on the temperature of the cooling water in a way so as to produce hot spots on the cylinder wall capable of provoking autoignition. Moreover, in the majority of practical cases, autoignition is produced by the spark plug, one of the least cooled parts in the engine. The first procedure therefore did not resemble that which most generally occurs in actual engine operation. All of these considerations caused us to reproduce similar hot spots at the spark plugs. The hot spots produced were of two kinds and designated with the name of thermo-electric spark plug and of metallic hot spot.

  6. Cold start fuel/air mixture supply device for spark ignition internal combustion engines

    SciTech Connect

    Ross, G.E.D.

    1984-06-05

    A combined accelerator pump and cold start fuel/air mixture supply device has an automatic throttle valve in a mixture supply passage, a fuel control valve controlling flow of fuel drawn into the passage through an inlet upstream of the throttle valve, and an air valve upstream of the fuel inlet. A primary spring tends to seat the air valve. A light, secondary spring urges a plunger against the air valve to augment the load of the primary spring for a predetermined time interval after the engine begins to run under its own power. A valve in a pipe opens automatically at the end of the predetermined time interval to apply engine inlet manifold depression to the end of the plunger remote from the air valve and thereby to separate the plunger from the air valve so that only the primary spring acts on the air valve.

  7. Direct Observation of Oil Consumption Mechanisms in a Production Spark Ignition Engine Using Fluorescence Techniques

    DTIC Science & Technology

    1994-05-01

    investigated for different piston ring end-gap configurations. A radiotracer was used to perform direct measurement of the oil consumption while Laser- induced ...and Instrumentation . . . . 43 3.1 General .......... ................... .. 43 3.2 Engine Description ....... ............. .. 43 3.3 Laser Induced ...Duty Diesels h" Non-dimensionalized Ah. k Proportionality constant for surface tension 11 (NI [mK]). Kpa kilo-Pascal LIF Laser Induced Fluorescence

  8. Performance of a Fuel-Injection Spark-Ignition Engine Using a Hydrogenated Safety Fuel

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Young, Alfred W

    1934-01-01

    This report presents the performance of a single-cylinder test engine using a hydrogenated safety fuel. The safety fuel has a flash point of 125 degrees f. (Cleveland open-dup method), which is high enough to remove most of the fire hazard, and an octane number of 95, which permits higher compression ratios to be used than are permissible with most undoped gasolines.

  9. Evaluation of Knock Behavior for Natural Gas - Gasoline Blends in a Light Duty Spark Ignited Engine

    DOE PAGES

    Pamminger, Michael; Sevik, James; Scarcelli, Riccardo; ...

    2016-01-01

    The compression ratio is a strong lever to increase the efficiency of an internal combustion engine. However, among others, it is limited by the knock resistance of the fuel used. Natural gas shows a higher knock resistance compared to gasoline, which makes it very attractive for use in internal combustion engines. The current paper describes the knock behavior of two gasoline fuels, and specific incylinder blend ratios with one of the gasoline fuels and natural gas. The engine used for these investigations is a single cylinder research engine for light duty application which is equipped with two separate fuel systems.more » Both fuels can be used simultaneously which allows for gasoline to be injected into the intake port and natural gas to be injected directly into the cylinder to overcome the power density loss usually connected with port fuel injection of natural gas. Adding natural gas at wide open throttle helps to reduce knock mitigating measures and increases the efficiency and power density compared to the other gasoline type fuels with lower knock resistance. The used methods, knock intensity and number of pressure waves, do not show significant differences in knock behavior for the natural gas - gasoline blends compared to the gasoline type fuels. A knock integral was used to describe the knock onset location of the fuels tested. Two different approaches were used to determine the experimental knock onset and were compared to the knock onset delivered by the knock integral (chemical knock onset). The gasoline type fuels show good agreement between chemical and experimental knock onset. However, the natural gas -gasoline blends show higher discrepancies comparing chemical and experimental knock onset.« less

  10. High gain preamplifier module (PAM) engineering prototype for the National Ignition Facility (NIF) laser system

    SciTech Connect

    Braucht, J; Browning, D; Crane, J K; Crawford, J; Deadrick, F J; Hawkins, S; Jones, B; Martinez, M; Penko, F; Skulina, M; Tilley, R; Wing, R

    1998-10-29

    We describe recent results and developments in the preamplifier module (PAM) engineering prototype located in NIF's front end or Optical Pulse Generation (OPG) system. This prototype uses the general laser design developed on a physics testbed and integrates NIP type packaging as well as controls and diagnostics. We will present laser, mechanical and electrical hardware designed and built to date as well as laser energetics measurements.

  11. Evaluation of Knock Behavior for Natural Gas - Gasoline Blends in a Light Duty Spark Ignited Engine

    SciTech Connect

    Pamminger, Michael; Sevik, James; Scarcelli, Riccardo; Wallner, Thomas; Wooldridge, Steven; Boyer, Brad; Hall, Carrie M.

    2016-10-17

    The compression ratio is a strong lever to increase the efficiency of an internal combustion engine. However, among others, it is limited by the knock resistance of the fuel used. Natural gas shows a higher knock resistance compared to gasoline, which makes it very attractive for use in internal combustion engines. The current paper describes the knock behavior of two gasoline fuels, and specific incylinder blend ratios with one of the gasoline fuels and natural gas. The engine used for these investigations is a single cylinder research engine for light duty application which is equipped with two separate fuel systems. Both fuels can be used simultaneously which allows for gasoline to be injected into the intake port and natural gas to be injected directly into the cylinder to overcome the power density loss usually connected with port fuel injection of natural gas. Adding natural gas at wide open throttle helps to reduce knock mitigating measures and increases the efficiency and power density compared to the other gasoline type fuels with lower knock resistance. The used methods, knock intensity and number of pressure waves, do not show significant differences in knock behavior for the natural gas - gasoline blends compared to the gasoline type fuels. A knock integral was used to describe the knock onset location of the fuels tested. Two different approaches were used to determine the experimental knock onset and were compared to the knock onset delivered by the knock integral (chemical knock onset). The gasoline type fuels show good agreement between chemical and experimental knock onset. However, the natural gas -gasoline blends show higher discrepancies comparing chemical and experimental knock onset.

  12. Ignition of Aluminum Particles and Clouds

    SciTech Connect

    Kuhl, A L; Boiko, V M

    2010-04-07

    Here we review experimental data and models of the ignition of aluminum (Al) particles and clouds in explosion fields. The review considers: (i) ignition temperatures measured for single Al particles in torch experiments; (ii) thermal explosion models of the ignition of single Al particles; and (iii) the unsteady ignition Al particles clouds in reflected shock environments. These are used to develop an empirical ignition model appropriate for numerical simulations of Al particle combustion in shock dispersed fuel explosions.

  13. Shock Initiation Experiments with Ignition and Growth Modeling on Low Density HMX

    NASA Astrophysics Data System (ADS)

    Garcia, Frank; Vandersall, Kevin; Tarver, Craig

    2013-06-01

    Shock initiation experiments on low density (1.24 and 1.64 g/cm3) HMX were performed to obtain in-situ pressure gauge data, characterize the run-distance-to-detonation behavior, and provide a basis for Ignition and Growth reactive flow modeling. A 101 mm diameter gas gun was utilized to initiate the explosive charges with manganin piezoresistive pressure gauge packages placed between packed layers (1.24 g/cm3) or sample disks pressed to low density (1.64 g/cm3) . The measured shock sensitivity of the 1.24 g/cm3 HMX was similar to that previously measured by Dick and Sheffield et al. and the 1.64 g/cm3 HMX was measured to be much less shock sensitive. Ignition and Growth model parameters were derived that yielded good agreement with the experimental data at both initial densities. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  14. Shock Initiation Experiments with Ignition and Growth Modeling on Low Density Composition B

    NASA Astrophysics Data System (ADS)

    Vandersall, Kevin S.; Garcia, Frank; Tarver, Craig M.

    2015-06-01

    Shock initiation experiments on low density (~1.2 and ~1.5 g/cm3) Composition B were performed to obtain in-situ pressure gauge data, characterize the run-distance-to-detonation behavior, and provide a basis for Ignition and Growth reactive flow modeling. A 101 mm diameter gas gun was utilized to initiate the explosive charges with manganin piezoresistive pressure gauge packages placed between packed layers (~1.2 g/cm3) confined in Teflon rings or sample disks pressed to low density (~1.5 g/cm3) . The shock sensitivity was found to increase with decreasing density as expected. Ignition and Growth model parameters were derived that yielded reasonable agreement with the experimental data at both initial densities. The shock sensitivity at the tested densities will be compared to prior work published as near full density material. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This work was funded in part by the Joint DoD-DOE Munitions Program.

  15. Ignition Rate Measurement of Laser-Ignited Coals

    SciTech Connect

    Chen, J.C.; Kabadi, V.

    1997-05-01

    We are proposing to establish a novel experiment to study the ignition of pulverized coals under conditions relevant to utility boiler. Specifically, our aims are to determine the ignition mechanism, which is either homogeneous or heterogeneous, of pulverized coal particles under various condition of particle size, coal type, freestream oxygen concentration, and heating rate. Furthermore, we will measure the ignition rate constants of various coals by direct measurement of the particle temperature at ignition, and incorporating this measurement into a mathematical model for the ignition process.

  16. Conversion of a micro, glow-ignition, two-stroke engine from nitromethane-methanol blend fuel to military jet propellant (JP-8)

    NASA Astrophysics Data System (ADS)

    Wiegand, Andrew L.

    The goal of the thesis "Conversion of a Micro, Glow-Ignition, Two-Stroke Engine from Nitromethane-Methanol Blend Fuel to Military Jet Propellant (JP-8)" was to demonstrate the ability to operate a small engine on JP-8 and was completed in two phases. The first phase included choosing, developing a test stand for, and baseline testing a nitromethane-methanol-fueled engine. The chosen engine was an 11.5 cc, glow-ignition, two-stroke engine designed for remote-controlled helicopters. A micro engine test stand was developed to load and motor the engine. Instrumentation specific to the low flow rates and high speeds of the micro engine was developed and used to document engine behavior. The second phase included converting the engine to operate on JP-8, completing JP-8-fueled steady-state testing, and comparing the performance of the JP-8-fueled engine to the nitromethane-methanol-fueled engine. The conversion was accomplished through a novel crankcase heating method; by heating the crankcase for an extended period of time, a flammable fuel-air mixture was generated in the crankcase scavenged engine, which greatly improved starting times. To aid in starting and steady-state operation, yttrium-zirconia impregnated resin (i.e. ceramic coating) was applied to the combustion surfaces. This also improved the starting times of the JP-8-fueled engine and ultimately allowed for a 34-second starting time. Finally, the steady-state data from both the nitromethane-methanol and JP-8-fueled micro engine were compared. The JP-8-fueled engine showed signs of increased engine friction while having higher indicated fuel conversion efficiency and a higher overall system efficiency. The minimal ability of JP-8 to cool the engine via evaporative effects, however, created the necessity of increased cooling air flow. The conclusion reached was that JP-8-fueled micro engines could be viable in application, but not without additional research being conducted on combustion phenomenon and

  17. Technology Development of a Fiber Optic-Coupled Laser Ignition System for Multi-Combustor Rocket Engines

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew E.; Bossard, John A.

    2002-01-01

    This paper addresses the progress of technology development of a laser ignition system at NASA Marshall Space Flight Center (MSFC). The first two years of the project focus on comprehensive assessments and evaluations of a novel dual-pulse laser concept, flight- qualified laser system, and the technology required to integrate the laser ignition system to a rocket chamber. With collaborations of the Department of Energy/Los Alamos National Laboratory (LANL) and CFD Research Corporation (CFDRC), MSFC has conducted 26 hot fire ignition tests with lab-scale laser systems. These tests demonstrate the concept feasibility of dual-pulse laser ignition to initiate gaseous oxygen (GOX)/liquid kerosene (RP-1) combustion in a rocket chamber. Presently, a fiber optic- coupled miniaturized laser ignition prototype is being implemented at the rocket chamber test rig for future testing. Future work is guided by a technology road map that outlines the work required for maturing a laser ignition system. This road map defines activities for the next six years, with the goal of developing a flight-ready laser ignition system.

  18. Ignition Quality Tester (IQT): An Alternative for Characterizing the Combustion Kinetics of Low Volatility Fuels

    SciTech Connect

    Osecky, E.; Bogin, G.; Ratcliff, M.; Luecke, J.; Chen, J. Y.; Zigler, B. T.

    2013-01-01

    The Ignition Quality Tester (IQT) is a constant volume spray combustion system that can be heated and pressurized to conditions that are similar to a diesel engine at top dead center. With no moving parts and the ability to handle low volatility fuels, the IQT can be a bridge between engines and traditional methods for studying chemical kinetics. By comparing experimental data with model predictions, the IQT has been used to validate skeletal kinetic models of ignition. CFD modeling of the IQT using KIVA-3V was used to predict ignition of n-heptane accurately. Operating the IQT in a regime where chemical kinetics dominates (long ignition delays) allowed NTC behavior to be observed for some isomers of heptane. Experimental results with the low volatility fuel heptamethylnonane also show NTC behavior. At long ignition delays, experimental results can be compared with 0-D detailed chemical mechanisms.

  19. Three-dimensional modeling of diesel engine intake flow, combustion and emissions

    NASA Technical Reports Server (NTRS)

    Reitz, R. D.; Rutland, C. J.

    1992-01-01

    A three-dimensional computer code (KIVA) is being modified to include state-of-the-art submodels for diesel engine flow and combustion: spray atomization, drop breakup/coalescence, multi-component fuel vaporization, spray/wall interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, soot and radiation, and the intake flow process. Improved and/or new submodels which were completed are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo'vich NOx, and spray/wall impingement with rebounding and sliding drops. Results to date show that adding the effects of unsteadiness and compressibility improves the accuracy of heat transfer predictions; spray drop rebound can occur from walls at low impingement velocities (e.g., in cold-starting); larger spray drops are formed at the nozzle due to the influence of vaporization on the atomization process; a laminar-and-turbulent characteristic time combustion model has the flexibility to match measured engine combustion data over a wide range of operating conditions; and finally, the characteristic time combustion model can also be extended to allow predictions of ignition. The accuracy of the predictions is being assessed by comparisons with available measurements. Additional supporting experiments are also described briefly. To date, comparisons with measured engine cylinder pressure and heat flux data were made for homogeneous charge, spark-ignited and compression-ignited engines. The model results are in good agreement with the experiments.

  20. Impact of Various Compression Ratio on the Compression Ignition Engine with Diesel and Jatropha Biodiesel

    NASA Astrophysics Data System (ADS)

    Sivaganesan, S.; Chandrasekaran, M.; Ruban, M.

    2017-03-01

    The present experimental investigation evaluates the effects of using blends of diesel fuel with 20% concentration of Methyl Ester of Jatropha biodiesel blended with various compression ratio. Both the diesel and biodiesel fuel blend was injected at 23º BTDC to the combustion chamber. The experiment was carried out with three different compression ratio. Biodiesel was extracted from Jatropha oil, 20% (B20) concentration is found to be best blend ratio from the earlier experimental study. The engine was maintained at various compression ratio i.e., 17.5, 16.5 and 15.5 respectively. The main objective is to obtain minimum specific fuel consumption, better efficiency and lesser Emission with different compression ratio. The results concluded that full load show an increase in efficiency when compared with diesel, highest efficiency is obtained with B20MEOJBA with compression ratio 17.5. It is noted that there is an increase in thermal efficiency as the blend ratio increases. Biodiesel blend has performance closer to diesel, but emission is reduced in all blends of B20MEOJBA compared to diesel. Thus this work focuses on the best compression ratio and suitability of biodiesel blends in diesel engine as an alternate fuel.

  1. Practical Possibilities of High-Altitude Flight with Exhaust-Gas Turbines in Connection with Spark Ignition Engines Comparative Thermodynamic and Flight Mechanical Investigations

    NASA Technical Reports Server (NTRS)

    Weise, A.

    1947-01-01

    As a means of preparing for high-altitude flight with spark-ignition engines in conjunction with exhaust-gas turbosuperchargers, various methods of modifying the exhaust-gas temperatures, which are initially higher than a turbine can withstand are mathematically compared. The thermodynamic results first obtained are then examined with respect to the effect on flight speed, climbing speed, ceiling, economy, and cruising range. The results are so presented in a generalized form that they may be applied to every appropriate type of aircraft design and a comparison with the supercharged engine without exhaust-gas turbine can be made.

  2. Engineering workstation: Sensor modeling

    NASA Technical Reports Server (NTRS)

    Pavel, M; Sweet, B.

    1993-01-01

    The purpose of the engineering workstation is to provide an environment for rapid prototyping and evaluation of fusion and image processing algorithms. Ideally, the algorithms are designed to optimize the extraction of information that is useful to a pilot for all phases of flight operations. Successful design of effective fusion algorithms depends on the ability to characterize both the information available from the sensors and the information useful to a pilot. The workstation is comprised of subsystems for simulation of sensor-generated images, image processing, image enhancement, and fusion algorithms. As such, the workstation can be used to implement and evaluate both short-term solutions and long-term solutions. The short-term solutions are being developed to enhance a pilot's situational awareness by providing information in addition to his direct vision. The long term solutions are aimed at the development of complete synthetic vision systems. One of the important functions of the engineering workstation is to simulate the images that would be generated by the sensors. The simulation system is designed to use the graphics modeling and rendering capabilities of various workstations manufactured by Silicon Graphics Inc. The workstation simulates various aspects of the sensor-generated images arising from phenomenology of the sensors. In addition, the workstation can be used to simulate a variety of impairments due to mechanical limitations of the sensor placement and due to the motion of the airplane. Although the simulation is currently not performed in real-time, sequences of individual frames can be processed, stored, and recorded in a video format. In that way, it is possible to examine the appearance of different dynamic sensor-generated and fused images.

  3. Shock Initiation Experiments Plus Ignition and Growth Modeling of Damaged LX-04 Charges

    NASA Astrophysics Data System (ADS)

    Chidester, Steven K.; Garcia, Frank; Vandersall, Kevin S.; Tarver, Craig M.

    2009-12-01

    Shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX and 15% Viton by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. The LX-04 charges were damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermal damaged LX-04 charges were heated to 190° C for a long enough time for the beta to delta phase transition to occur and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while the thermally damaged LX-04 was much more shock sensitive. The pristine LX-04 Ignition and Growth model, modified only by igniting a larger amount of explosive during shock compression based on the damaged charge density, accurately calculated the increased shock sensitivity of the three damaged charges.

  4. SHOCK INITIATION EXPERIMENTS PLUS IGNITION AND GROWTH MODELING OF DAMAGED LX-04 CHARGES

    SciTech Connect

    Chidester, S K; Garcia, F; Vandersall, K S; Tarver, C M

    2009-06-23

    Shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX and 15% Viton by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. The LX-04 charges were damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermal damaged LX-04 charges were heated to 190 C for a long enough time for the beta to delta phase transition to occur and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while the thermally damaged LX-04 was much more shock sensitive. The pristine LX-04 Ignition and Growth model, modified only by igniting a larger amount of explosive during shock compression based on the damaged charge density, accurately calculated the increased shock sensitivity of the three damaged charges.

  5. Relative importance of fuel management, ignition management and weather for area burned: Evidence from five landscape-fire-succession models

    Treesearch

    Geoffrey J. Cary; Mike D. Flannigan; Robert E. Keane; Ross A. Bradstock; Ian D. Davies; James M. Lenihan; Chao Li; Kimberley A. Logan; Russell A. Parsons

    2009-01-01

    The behaviour of five landscape fire models (CAFE, FIRESCAPE, LAMOS(HS), LANDSUM and SEMLAND) was compared in a standardised modelling experiment. The importance of fuel management approach, fuel management effort, ignition management effort and weather in determining variation in area burned and number of edge pixels burned (a measure of potential impact on assets...

  6. Status on Technology Development of Optic Fiber-Coupled Laser Ignition System for Rocket Engine Applications

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew; Bossard, John

    2003-01-01

    To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concept: not only offer system simplicity, but also enhance the combustion performance. Test results have shown that chamber performance is markedly high even at a low chamber length-to-diameter ratio. This incentive can be translated to a convenience in the thrust chamber packaging.

  7. Status on Technology Development of Optic Fiber-Coupled Laser Ignition System for Rocket Engine Applications

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew; Bossard, John

    2003-01-01

    To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concept: not only offer system simplicity, but also enhance the combustion performance. Test results have shown that chamber performance is markedly high even at a low chamber length-to-diameter ratio. This incentive can be translated to a convenience in the thrust chamber packaging.

  8. A study of combustion of hydrogen-enriched gasoline in a spark ignition engine

    SciTech Connect

    Apostolescu, N.; Chiriac, R.

    1996-09-01

    An investigation has been done on the influence of small amounts of hydrogen added to hydrocarbons-air mixtures on combustion characteristics. The effect of hydrogen addition to a hydrocarbon-air mixture was firstly approached in an experimental bomb, to measure the laminar burning velocity and the shift of lean flammability limit. Experiments carried out with a single-cylinder four stroke SI engine confirmed the possibility of expanding the combustion stability limit, which correlates well with the general trend of enhancing the rate of combustion. An increase of brake thermal efficiency has been obtained with a reduction of HC emissions; the NO{sub x} emissions were higher, except for very lean mixtures.

  9. Particle-In-Cell modeling of Fast Ignition experiments on the Titan Laser

    NASA Astrophysics Data System (ADS)

    Link, Anthony; Akli, K. U.; Beg, F.; Chen, C. D.; Davies, J. R.; Freeman, R. R.; Kemp, G. E.; Li, K.; McLean, H. S.; Morace, A.; Patel, P. K.; Schumacher, D. W.; Sorokovikova, A. V.; Stephens, R.; Streeter, M. J. V.; Wertepny, D.; Westhover, B.

    2012-10-01

    We report on particle-in-cell-modeling (PIC) of fast ignition experiments conducted on the Titan laser. The Titan laser was used to irradiate multilayer planar targets at intensities greater than 10^20 Wcm-2 to diagnose the laser to electron coupling, electron beam divergence, and energy spectrum of the hot electrons at relativistic intensities. Hot electron beam properties were inferred through buried fluors, escaping electrons and bremsstrahlung measurements. The PIC simulations of the experiment were conducted in two stages: a high resolution laser plasma interaction (LPI) simulation using measured on shot laser parameters but with a subscale target; and a lower resolution transport simulation containing the full scale multilayer target. The transport simulation utilized the electron source based on the output of the LPI simulation and included necessary models to simulate the experimental diagnostics. Comparison of the predicted electron source properties and the experimental data will be presented.

  10. Analysis of the dynamics of coal char combustion with ignition and extinction phenomena: Shrinking core model

    SciTech Connect

    Sadhukhan, A.K.; Gupta, P.; Saha, R.K.

    2008-09-15

    Single-particle combustion of coal char is analyzed using a generalized shrinking core model. Finite volume method, which was earlier employed by the authors in solving moving boundary problems involving fluid-solid noncatalytic reactions in general, is used to solve fully transient mass and energy equations. The model takes into account convection and diffusion inside the particle as well as in the boundary layer. The computed results are compared with the experimental data of the authors for combustion of coal char in a fluidized bed combustor. The effects of parameters such as bulk temperature and initial particle radius on the combustion dynamics are examined. The phenomena of ignition and extinction are also investigated. Finally, the importance of Stefan flow, originating due to nonequimolar counterdiffusion, on combustion of coal char is analyzed.

  11. Ignition Delay Experiments with Small-scale Rocket Engine at Simulated Altitude Conditions Using Various Fuels with Nitric Acid Oxidants / Dezso J. Ladanyi

    NASA Technical Reports Server (NTRS)

    Ladanyi, Dezso J

    1952-01-01

    Ignition delay determinations of several fuels with nitric oxidants were made at simulated altitude conditions utilizing a small-scale rocket engine of approximately 50 pounds thrust. Included in the fuels were aniline, hydrazine hydrate, furfuryl alcohol, furfuryl mercaptan, turpentine, and mixtures of triethylamine with mixed xylidines and diallyaniline. Red fuming, white fuming, and anhydrous nitric acids were used with and without additives. A diallylaniline - triethylamine mixture and a red fuming nitric acid analyzing 3.5 percent water and 16 percent NO2 by weight was found to have a wide temperature-pressure ignition range, yielding average delays from 13 milliseconds at 110 degrees F to 55 milliseconds at -95 degrees F regardless of the initial ambient pressure that ranged from sea-level pressure altitude of 94,000 feet.

  12. Hypersonic research engine project. Phase 2: Aerothermodynamic Integration Model (AIM) test report

    NASA Technical Reports Server (NTRS)

    Andersen, W. L.; Kado, L.

    1975-01-01

    The Hypersonic Research Engine-Aerothermodynamic Integration Model (HRE-AIM) was designed, fabricated, and tested in the Hypersonic Tunnel Facility. The HRE-AIM is described along with its installation in the wind tunnel facility. Test conditions to which the HRE-AIM was subjected and observations made during the tests are discussed. The overall engine performance, component interaction, and ignition limits for the design are evaluated.

  13. Microgravity ignition experiment

    NASA Technical Reports Server (NTRS)

    Motevalli, Vahid; Elliott, William; Garrant, Keith

    1992-01-01

    The purpose of this project is to develop a flight ready apparatus of the microgravity ignition experiment for the GASCan 2 program. This involved redesigning, testing, and making final modifications to the existing apparatus. The microgravity ignition experiment is intended to test the effect of microgravity on the time to ignition of a sample of alpha-cellulose paper. An infrared heat lamp is used to heat the paper sample within a sealed canister. The interior of the canister was redesigned to increase stability and minimize conductive heat transfer to the sample. This design was fabricated and tested and a heat transfer model of the paper sample was developed.

  14. Engineering architecture of the neutron Time-of-Flight (nToF) diagnostic suite at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Clancy, T. J.; Caggiano, J.; McNaney, J.; Eckart, M.; Moran, M.; Glebov, V. Y.; Knauer, J.; Hatarik, R.; Friedrich, S.; Zacharias, R.; Carpenter, A.; Shoup, M. J.; Buczek, T.; Yeoman, M.; Zeid, Z.; Zaitseva, N.; Talison, B.; Worden, J.; Rice, B.; Duffy, T.; Pruyne, A.; Marshall, K.

    2014-09-01

    This paper describes the engineering architecture and function of the neutron Time-of-Flight (nToF) diagnostic suite installed on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL). These instruments provide key measures of neutron yield, ion temperature, drift velocity, neutron bang-time, and neutron downscatter ratio. Currently, there are five nToFs on three collimated lines-of-site (LOS) from 18m to 27m from Target Chamber Center, and three positioned 4.5m from TCC, within the NIF Target Chamber but outside the vacuum and confinement boundary by use of re-entrant wells on three other LOS. NIF nToFs measure the time history and equivalent energy spectrum of reaction generated neutrons from a NIF experiment. Neutrons are transduced to electrical signals, which are then carried either by coaxial or Mach-Zehnder transmission systems that feed divider assemblies and fiducially timed digitizing oscilloscopes outside the NIF Target Bay (TB) radiation shield wall. One method of transduction employs a two-stage process wherein a neutron is converted to scintillation photons in hydrogen doped plastic (20x40mm) or bibenzyl crystals (280x1050mm), which are subsequently converted to an electrical signal via a photomultiplier tube or a photo-diode. An alternative approach uses a single-stage conversion of neutrons-to-electrons by use of a thin (0.25 to 2 mm) Chemical Vapor Deposition Diamond (CVDD) disc (2 to 24mm radius) under high voltage bias. In comparison to the scintillator method, CVDDs have fast rise and decay times (

  15. NIF Ignition

    DTIC Science & Technology

    2005-07-01

    particles created by the DT fusion reaction ) at an ion temperature of about 10 keV. Reaching these conditions is primarily controlled by the implosion...confinement fusion (ICF) ignition at the National Ignition Facility (NIF) by 2010, including the use of beryllium targets. 14. SUBJECTTERMS 15. NUMBER OF...itigation ............................................................................ 37 3.6 D iagnostics

  16. Comparative combustion studies on various plant oil esters and the long term effects of an ethyl ester on a compression ignition engine

    SciTech Connect

    Hawkins, C.S.; Fuls, J.

    1982-01-01

    Combustion studies on both ethyl and methyl esters of various plant oils were carried out using the same engine for all the tests so that comparative studies could be achieved. Twelve esters were tested and the pertinent data was recorded. Some of the more important results are published in this paper to serve as a comparative guide to the study of plant oil esters as fuel. Bruwer et. al. (1980) suggested the use of plant oil esters to prevent injector coking in modern compression ignition engines. Very little information is available on the long term effects of such ester use. Cyclic endurance tests have been carried out on Perkins engines running on ethyl esters of sunflower oil. The exciting results of this work are reported, with specific reference to one tractor engine which has recorded more than 1 300 trouble free hours. 3 tables.

  17. Experimental Investigation of Piston Heat Transfer in a Light Duty Engine Under Conventional Diesel, Homogeneous Charge Compression Ignition, and Reactivity Controlled Compression Ignition Combustion Regimes

    DTIC Science & Technology

    2014-01-15

    and cylinder liners [10, 11]. More recently, measurements have been made on the piston surface with engines operating under RCCI and CDC combustion...An experimental study has been conducted to provide insight into heat transfer to the piston of a light-duty single- cylinder research engine under...timing or injection timing, when a single fuel is used. RCCI utilizes in- cylinder fuel reactivity stratification by utilizing a second fuel. Typically

  18. On the effect of Di-Ethyl-Ether (DEE) injection upon the cold starting of a biodiesel fuelled compression ignition engine

    NASA Astrophysics Data System (ADS)

    Clenci, Adrian; Niculescu, Rodica; Iorga-Simǎn, Victor; Tricǎ, Alina; Danlos, Amélie

    2017-02-01

    The use of biodiesel fuel in compression ignition engines has the potential to reduce CO2, which can lead to a reduction in global warming and environmental hazards. Biodiesel is an attractive fuel, as it is made from renewable resources. A major drawback associated with the use of biodiesel, however, is its poor cold flow properties, which have a direct influence on the cold starting performance of the engine. This paper is a consequence of a study on assessing the cold-starting performance of a compression ignition engine fueled with different blends of fossil diesel fuel and biodiesel. Through experimental investigations, it was found that the engine starting at -20°C was no longer possible in the case of using B50 (50% diesel + 50% biofuel made from sunflower oil). In order to "force" the engine starting in this particular situation, Di-Ethyl-Ether (DEE) was injected into the intake manifold. DEE being a highly flammable substance, the result was a sudden and explosive engine starting, the peak pressure in the monitored cylinder in the first successful engine cycle being almost twice the one which is usually considered as normal. Thus, to explain the observed phenomena, we launched this work relying on the analysis of the in-cylinder instantaneous pressure evolution, which was acquired during cranking, stabilizing and idling phases. Moreover, since the cause of the sudden and explosive engine starting was the DEE, by using a CFD approach, we also obtained results regarding the inter-cylinder distribution of the injected DEE.

  19. A Review of Sub-Scale Test Methods to Evaluate the Friction and Wear of Ring and Liner Materials for Spark- and Compression Ignition Engines

    SciTech Connect

    Blau, P.J.

    2002-01-22

    A review was conducted of past laboratory-scale test methods and to assess their validity for ranking materials and lubricants for use as piston and liner materials in compression-ignition (CI) and spark-ignition (SI) engines. Most of the previous work was aimed at simulating SI engine environments. This report begins with a discussion of the numerous factors that can affect the validity of an approach to simulating engine conditions in a laboratory. These include not only mechanical, chemical and thermal factors, but also human factors as regards how the vehicle is operated and maintained. The next section provides an annotated review of open literature publications that address the issues of laboratory simulation of engine components. A comparison of these studies indicates a lack of sufficient standardization in procedures to enable a systematic comparison of one publication to another. There were just a few studies that compared several laboratory test methods to engine test results, and these indicated that some test methods correlate, at least qualitatively, better than others. The last section provides a series of recommendations for improving the accuracy and validity of laboratory-scale simulations of engine behavior. It became clear that much of the engine wear damage occurs during start-up when the engine is cold, and this calls into the question the usefulness of test methods that attempt to simulate steady-state running conditions. It is recommended that a new standard test method, perhaps developed with the help of the ASTM wear and erosion committee, be developed. It would use cold start-up conditions in the presence of degraded oil, or simulated degraded oil.

  20. Experimental Investigation of Fuel-Reactivity Controlled Compression Ignition (RCCI) Combustion Mode in a Multi-Cylinder, Light-Duty Diesel Engine

    SciTech Connect

    Cho, Kukwon; Curran, Scott; Prikhodko, Vitaly Y; Sluder, Scott; Parks, II, James E; Wagner, Robert M

    2011-01-01

    An experimental study was performed to provide the combustion and emission characteristics resulting from fuel-reactivity controlled compression ignition (RCCI) combustion mode utilizing dual-fuel approach in a light-duty, multi-cylinder diesel engine. In-cylinder fuel blending using port fuel injection of gasoline before intake valve opening (IVO) and early-cycle, direct injection of diesel fuel was used as the charge preparation and fuel blending strategy. In order to achieve the desired auto-ignition quality through the stratification of the fuel-air equivalence ratio ( ), blends of commercially available gasoline and diesel fuel were used. Engine experiments were performed at an engine speed of 2300rpm and an engine load of 4.3bar brake mean effective pressure (BMEP). It was found that significant reduction in both nitrogen oxide (NOx) and particulate matter (PM) was realized successfully through the RCCI combustion mode even without applying exhaust gas recirculation (EGR). However, high carbon monoxide (CO) and hydrocarbon (HC) emissions were observed. The low combustion gas temperature during the expansion and exhaust processes seemed to be the dominant source of high CO emissions in the RCCI combustion mode. The high HC emissions during the RCCI combustion mode could be due to the increased combustion quenching layer thickness as well as the -stratification at the periphery of the combustion chamber. The slightly higher brake thermal efficiency (BTE) of the RCCI combustion mode was observed than the other combustion modes, such as the conventional diesel combustion (CDC) mode, and single-fuel, premixed charge compression ignition (PCCI) combustion mode. The parametric study of the RCCI combustion mode revealed that the combustion phasing and/or the peak cylinder pressure rise rate of the RCCI combustion mode could be controlled by several physical parameters premixed ratio (rp), intake swirl intensity, and start of injection (SOI) timing of directly