Effect of Operating and Sampling Conditions on the Exhaust Gas Composition of Small-Scale Power Generators

PubMed Central

Smits, Marianne; Vanpachtenbeke, Floris; Horemans, Benjamin; De Wael, Karolien; Hauchecorne, Birger; Van Langenhove, Herman; Demeestere, Kristof; Lenaerts, Silvia

2012-01-01

Small stationary diesel engines, like in generator sets, have limited emission control measures and are therefore responsible for 44% of the particulate matter (PM) emissions in the United States. The diesel exhaust composition depends on operating conditions of the combustion engine. Furthermore, the measurements are influenced by the used sampling method. This study examines the effect of engine loading and exhaust gas dilution on the composition of small-scale power generators. These generators are used in different operating conditions than road-transport vehicles, resulting in different emission characteristics. Experimental data were obtained for gaseous volatile organic compounds (VOC) and PM mass concentration, elemental composition and nitrate content. The exhaust composition depends on load condition because of its effect on fuel consumption, engine wear and combustion temperature. Higher load conditions result in lower PM concentration and sharper edged particles with larger aerodynamic diameters. A positive correlation with load condition was found for K, Ca, Sr, Mn, Cu, Zn and Pb adsorbed on PM, elements that originate from lubricating oil or engine corrosion. The nitrate concentration decreases at higher load conditions, due to enhanced nitrate dissociation to gaseous NO at higher engine temperatures. Dilution on the other hand decreases PM and nitrate concentration and increases gaseous VOC and adsorbed metal content. In conclusion, these data show that operating and sampling conditions have a major effect on the exhaust gas composition of small-scale diesel generators. Therefore, care must be taken when designing new experiments or comparing literature results. PMID:22442670

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

NASA Astrophysics Data System (ADS)

Lack, D. A.; Corbett, J. J.

2012-01-01

The International Maritime Organization (IMO) has moved to address the health and climate impact of the emissions from the combustion of low-quality residual fuels within the commercial shipping industry. Fuel sulfur content (FS) limits and an efficiency design index for future ships are examples of such IMO actions. The impacts of black carbon (BC) emissions from shipping are now under review by the IMO, with a particular focus on the potential impacts of future Arctic shipping. Recognizing that associating impacts with BC emissions requires both ambient and onboard observations, we provide recommendations for the measurement of BC. We also evaluate current insights regarding the effect of ship speed (engine load), fuel quality and exhaust gas scrubbing on BC emissions from ships. Observations demonstrate that BC emission factors (EFBC) increases 3 to 6 times at very low engine loads (<25% compared to EFBC at 85-100% load); absolute BC emissions (per nautical mile of travel) also increase up to 100% depending on engine load, even with reduced load fuel savings. If fleets were required to operate at lower maximum engine loads, presumably associated with reduced speeds, then engines could be re-tuned, which would reduce BC emissions. Ships operating in the Arctic are likely running at highly variable engine loads (25-100%) depending on ice conditions and ice breaking requirements. The ships operating at low load may be emitting up to 50% more BC than they would at their rated load. Such variable load conditions make it difficult to assess the likely emissions rate of BC. Current fuel sulfur regulations have the effect of reducing EFBC by an average of 30% and potentially up to 80% regardless of engine load; a removal rate similar to that of scrubbers. Uncertainties among current observations demonstrate there is a need for more information on (a) the impact of fuel quality on EFBC using robust measurement methods and (b) the efficacy of scrubbers for the removal of particulate matter by size and composition.

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

NASA Astrophysics Data System (ADS)

Lack, D. A.; Corbett, J. J.

2012-05-01

The International Maritime Organization (IMO) has moved to address the health and climate impact of the emissions from the combustion of low-quality residual fuels within the commercial shipping industry. Fuel sulfur content (FS) limits and an efficiency design index for future ships are examples of such IMO actions. The impacts of black carbon (BC) emissions from shipping are now under review by the IMO, with a particular focus on the potential impacts of future Arctic shipping. Recognizing that associating impacts with BC emissions requires both ambient and onboard observations, we provide recommendations for the measurement of BC. We also evaluate current insights regarding the effect of ship speed (engine load), fuel quality and exhaust gas scrubbing on BC emissions from ships. Observations demonstrate that BC emission factors (EFBC) increases 3 to 6 times at very low engine loads (<25% compared to EFBC at 85-100% load); absolute BC emissions (per nautical mile of travel) also increase up to 100% depending on engine load, even with reduced load fuel savings. If fleets were required to operate at lower maximum engine loads, presumably associated with reduced speeds, then engines could be re-tuned, which would reduce BC emissions. Ships operating in the Arctic are likely running at highly variable engine loads (25-100%) depending on ice conditions and ice breaking requirements. The ships operating at low load may be emitting up to 50% more BC than they would at their rated load. Such variable load conditions make it difficult to assess the likely emissions rate of BC. Current fuel sulfur regulations have the effect of reducing EFBC by an average of 30% and potentially up to 80% regardless of engine load; a removal rate similar to that of scrubbers. Uncertainties among current observations demonstrate there is a need for more information on a) the impact of fuel quality on EFBC using robust measurement methods and b) the efficacy of scrubbers for the removal of particulate matter by size and composition.

Transient Three-Dimensional Analysis of Nozzle Side Load in Regeneratively Cooled Engines

NASA Technical Reports Server (NTRS)

ng, Ten-See

2005-01-01

Nozzle side loads are potentially detrimental to the integrity and life of almost all launch vehicles. the lack of a detailed prediction capability results in reducing life and increased weight for reusable nozzle systems. A clear understanding of the mechanism that contribute to side loads during engine startup, shutdown, and steady-state operations must be established. A CFD based predictive tool must be developed to aid the understanding of side load physics and development of future reusable engine.

The effect of insulated combustion chamber surfaces on direct-injected diesel engine performance, emissions, and combustion

NASA Technical Reports Server (NTRS)

Dickey, Daniel W.; Vinyard, Shannon; Keribar, Rifat

1988-01-01

The combustion chamber of a single-cylinder, direct-injected diesel engine was insulated with ceramic coatings to determine the effect of low heat rejection (LHR) operation on engine performance, emissions, and combustion. In comparison to the baseline cooled engine, the LHR engine had lower thermal efficiency, with higher smoke, particulate, and full load carbon monoxide emissions. The unburned hydrocarbon emissions were reduced across the load range. The nitrous oxide emissions increased at some part-load conditions and were reduced slightly at full loads. The poor LHR engine performance was attributed to degraded combustion characterized by less premixed burning, lower heat release rates, and longer combustion duration compared to the baseline cooled engine.

Transient Three-Dimensional Side Load Analysis of a Film Cooled Nozzle

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Guidos, Mike

2008-01-01

Transient three-dimensional numerical investigations on the side load physics for an engine encompassing a film cooled nozzle extension and a regeneratively cooled thrust chamber, were performed. The objectives of this study are to identify the three-dimensional side load physics and to compute the associated aerodynamic side load using an anchored computational methodology. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and a transient inlet history based on an engine system simulation. Ultimately, the computational results will be provided to the nozzle designers for estimating of effect of the peak side load on the nozzle structure. Computations simulating engine startup at ambient pressures corresponding to sea level and three high altitudes were performed. In addition, computations for both engine startup and shutdown transients were also performed for a stub nozzle, operating at sea level. For engine with the full nozzle extension, computational result shows starting up at sea level, the peak side load occurs when the lambda shock steps into the turbine exhaust flow, while the side load caused by the transition from free-shock separation to restricted-shock separation comes at second; and the side loads decreasing rapidly and progressively as the ambient pressure decreases. For the stub nozzle operating at sea level, the computed side loads during both startup and shutdown becomes very small due to the much reduced flow area.

Investigating the pros and cons of browns gas and varying EGR on combustion, performance, and emission characteristics of diesel engine.

PubMed

Thangaraj, Suja; Govindan, Nagarajan

2018-01-01

The significance of mileage to the fruitful operation of a trucking organization cannot be downplayed. Fuel is one of the biggest variable expenses in a trucking wander. An attempt is made in this research to improve the combustion efficiency of a diesel engine for better fuel economy by introducing hydroxy gas which is also called browns gas or HHO gas in the suction line, without compromising performance and emission. Brown's gas facilitates the air-fuel mixture to ignite faster and efficient combustion. By considering safety and handling issues in automobiles, HHO gas generation by electrolysis of water in the presence of sodium bicarbonate electrolytes (NaHCO 3 ) and usage was explored in this research work over compressed pure hydrogen, due to generation and capacity of immaculate hydrogen as of now confines the application in diesel engine operation. Brown's gas was utilized as a supplementary fuel in a single-cylinder, four-stroke compression ignition (CI) engine. Experiments were carried out on a constant speed engine at 1500 rpm, result shows at constant HHO flow rate of 0.73 liter per minute (LPM), brake specific fuel consumption (BSFC) decreases by 7% at idle load to 16% at full load, and increases brake thermal efficiency (BTE) by 8.9% at minimum load to 19.7% at full load. In the dual fuel (diesel +HHO) operation, CO emissions decreases by 19.4, 64.3, and 34.6% at 25, 50, and 75% load, respectively, and unburned hydrocarbon (UHC) emissions decreased by 11.3% at minimum load to 33.5% at maximum load at the expense of NO x emission increases by 1.79% at 75% load and 1.76% at full load than neat diesel operation. The negative impact of an increase in NO x is reduced by adding EGR. It was evidenced in this experimental work that the use of Brown's gas with EGR in the dual fuel mode in a diesel engine improves the fuel efficiency, performance, and reduces the exhaust emissions.

Control system and method for a power delivery system having a continuously variable ratio transmission

DOEpatents

Frank, A.A.

1984-07-10

A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine. 4 figs.

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2013 CFR

2013-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2014 CFR

2014-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2012 CFR

2012-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2011 CFR

2011-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

The Grid Density Dependence of the Unsteady Pressures of the J-2X Turbines

NASA Technical Reports Server (NTRS)

Schmauch, Preston B.

2011-01-01

The J-2X engine was originally designed for the upper stage of the cancelled Crew Launch Vehicle. Although the Crew Launch Vehicle was cancelled the J-2X engine, which is currently undergoing hot-fire testing, may be used on future programs. The J-2X engine is a direct descendent of the J-2 engine which powered the upper stage during the Apollo program. Many changes including a thrust increase from 230K to 294K lbf have been implemented in this engine. As part of the design requirements, the turbine blades must meet minimum high cycle fatigue factors of safety for various vibrational modes that have resonant frequencies in the engine's operating range. The unsteady blade loading is calculated directly from CFD simulations. A grid density study was performed to understand the sensitivity of the spatial loading and the magnitude of the on blade loading due to changes in grid density. Given that the unsteady blade loading has a first order effect on the high cycle fatigue factors of safety, it is important to understand the level of convergence when applying the unsteady loads. The convergence of the unsteady pressures of several grid densities will be presented for various frequencies in the engine's operating range.

Overview of Aerothermodynamic Loads Definition Study

NASA Technical Reports Server (NTRS)

Povinelli, L. A.

1985-01-01

The Aerothermodynamic Loads Definition were studied to develop methods to more accurately predict the operating environment in the space shuttle main engine (SSME) components. Development of steady and time-dependent, three-dimensional viscous computer codes and experimental verification and engine diagnostic testing are considered. The steady, nonsteady, and transient operating loads are defined to accurately predict powerhead life. Improvements in the structural durability of the SSME turbine drive systems depends on the knowledge of the aerothermodynamic behavior of the flow through the preburner, turbine, turnaround duct, gas manifold, and injector post regions.

40 CFR 1045.505 - How do I test engines using discrete-mode or ramped-modal duty cycles?

Code of Federal Regulations, 2011 CFR

2011-07-01

... your own testing. If you submit certification test data collected with both discrete-mode and ramped...-use operation. (d) For full-load operating modes, operate the engine at wide-open throttle. (e) See 40...

23 CFR 661.5 - What definitions apply to this regulation?

Code of Federal Regulations, 2014 CFR

2014-04-01

... prescribed scope of work. Preliminary engineering (PE) means planning, survey, design, engineering, and... survey staking functions considered necessary for effective control of the construction operations... carrying capacity (comparison of the original design load to the State legal load), clearance, or approach...

23 CFR 661.5 - What definitions apply to this regulation?

Code of Federal Regulations, 2012 CFR

2012-04-01

... prescribed scope of work. Preliminary engineering (PE) means planning, survey, design, engineering, and... survey staking functions considered necessary for effective control of the construction operations... carrying capacity (comparison of the original design load to the State legal load), clearance, or approach...

23 CFR 661.5 - What definitions apply to this regulation?

Code of Federal Regulations, 2011 CFR

2011-04-01

... prescribed scope of work. Preliminary engineering (PE) means planning, survey, design, engineering, and... survey staking functions considered necessary for effective control of the construction operations... carrying capacity (comparison of the original design load to the State legal load), clearance, or approach...

23 CFR 661.5 - What definitions apply to this regulation?

Code of Federal Regulations, 2010 CFR

2010-04-01

... prescribed scope of work. Preliminary engineering (PE) means planning, survey, design, engineering, and... survey staking functions considered necessary for effective control of the construction operations... carrying capacity (comparison of the original design load to the State legal load), clearance, or approach...

23 CFR 661.5 - What definitions apply to this regulation?

Code of Federal Regulations, 2013 CFR

2013-04-01

... prescribed scope of work. Preliminary engineering (PE) means planning, survey, design, engineering, and... survey staking functions considered necessary for effective control of the construction operations... carrying capacity (comparison of the original design load to the State legal load), clearance, or approach...

Flow Separation Side Loads Excitation of Rocket Nozzle FEM

NASA Technical Reports Server (NTRS)

Smalley, Kurt B.; Brown, Andrew; Ruf, Joseph; Gilbert, John

2007-01-01

Modern rocket nozzles are designed to operate over a wide range of altitudes, and are also built with large aspect ratios to enable high efficiencies. Nozzles designed to operate over specific regions of a trajectory are being replaced in modern launch vehicles by those that are designed to operate from earth to orbit. This is happening in parallel with modern manufacturing and wall cooling techniques allowing for larger aspect ratio nozzles to be produced. Such nozzles, though operating over a large range of altitudes and ambient pressures, are typically designed for one specific altitude. Above that altitude the nozzle flow is 'underexpanded' and below that altitude, the nozzle flow is 'overexpanded'. In both conditions the nozzle produces less than the maximum possible thrust at that altitude. Usually the nozzle design altitude is well above sea level, leaving the nozzle flow in an overexpanded state for its start up as well as for its ground testing where, if it is a reusable nozzle such as the Space Shuttle Main Engine (SSME), the nozzle will operate for the majority of its life. Overexpansion in a rocket nozzle presents the critical, and sometimes design driving, problem of flow separation induced side loads. To increase their understanding of nozzle side loads, engineers at MSFC began an investigation in 2000 into the phenomenon through a task entitled "Characterization and Accurate Modeling of Rocket Engine Nozzle Side Loads", led by A. Brown. The stated objective of this study was to develop a methodology to accurately predict the character and magnitude of nozzle side loads. The study included further hot-fire testing of the MC-l engine, cold flow testing of subscale nozzles, CFD analyses of both hot-fire and cold flow nozzle testing, and finite element (fe.) analysis of the MC-1 engine and cold flow tested nozzles. A follow on task included an effort to formulate a simplified methodology for modeling a side load during a two nodal diameter fluid/structure interaction for a single moment in time.

Mutagenicity of biodiesel or diesel exhaust particles and the effect of engine operating conditions.

PubMed

Kisin, Elena R; Shi, X C; Keane, Michael J; Bugarski, Aleksandar B; Shvedova, Anna A

2013-03-01

Changing the fuel supply from petroleum based ultra-low sulfur diesel (ULSD) to biodiesel and its blends is considered by many to be a viable option for controlling exposures to particulate material (PM). This is critical in the mining industry where approximately 28,000 underground miners are potentially exposed to relatively high concentrations of diesel particulate matter (DPM). This study was conducted to investigate the mutagenic potential of diesel engine emissions (DEE) from neat (B100) and blended (B50) soy-based fatty acid methyl ester (FAME) biodiesel in comparison with ULSD PM using different engine operating conditions and exhaust aftertreatment configurations. The DPM samples were collected for engine equipped with either a standard muffler or a combination of the muffler and diesel oxidation catalytic converter (DOC) that was operated at four different steady-state modes. Bacterial gene mutation activity of DPM was tested on the organic solvent extracts using the Ames Salmonella assay. The results indicate that mutagenic activity of DPM was strongly affected by fuels, engine operating conditions, and exhaust aftertreatment systems. The mutagenicity was increased with the fraction of biodiesel in the fuel. While the mutagenic activity was observed in B50 and B100 samples collected from both light-and heavy-load operating conditions, the ULSD samples were mutagenic only at light-load conditions. The presence of DOC in the exhaust system resulted in the decreased mutagenicity when engine was fueled with B100 and B50 and operated at light-load conditions. This was not the case when engine was fueled with ULSD. Heavy-load operating condition in the presence of DOC resulted in a decrease of mutagenicity only when engine was fueled with B50, but not B100 or ULSD. Therefore, the results indicate that DPM from neat or blended biodiesel has a higher mutagenic potency than that one of ULSD. Further research is needed to investigate the health effect of biodiesel as well as efficiency of DOC or other exhaust aftertreatment systems.

Mutagenicity of biodiesel or diesel exhaust particles and the effect of engine operating conditions

PubMed Central

Kisin, Elena R; Shi, X.C; Keane, Michael J; Bugarski, Aleksandar B; Shvedova, Anna A

2015-01-01

Background Changing the fuel supply from petroleum based ultra-low sulfur diesel (ULSD) to biodiesel and its blends is considered by many to be a viable option for controlling exposures to particulate material (PM). This is critical in the mining industry where approximately 28,000 underground miners are potentially exposed to relatively high concentrations of diesel particulate matter (DPM). This study was conducted to investigate the mutagenic potential of diesel engine emissions (DEE) from neat (B100) and blended (B50) soy-based fatty acid methyl ester (FAME) biodiesel in comparison with ULSD PM using different engine operating conditions and exhaust aftertreatment configurations. Methods The DPM samples were collected for engine equipped with either a standard muffler or a combination of the muffler and diesel oxidation catalytic converter (DOC) that was operated at four different steady-state modes. Bacterial gene mutation activity of DPM was tested on the organic solvent extracts using the Ames Salmonella assay. Results The results indicate that mutagenic activity of DPM was strongly affected by fuels, engine operating conditions, and exhaust aftertreatment systems. The mutagenicity was increased with the fraction of biodiesel in the fuel. While the mutagenic activity was observed in B50 and B100 samples collected from both light-and heavy-load operating conditions, the ULSD samples were mutagenic only at light-load conditions. The presence of DOC in the exhaust system resulted in the decreased mutagenicity when engine was fueled with B100 and B50 and operated at light-load conditions. This was not the case when engine was fueled with ULSD. Heavy-load operating condition in the presence of DOC resulted in a decrease of mutagenicity only when engine was fueled with B50, but not B100 or ULSD. Conclusions Therefore, the results indicate that DPM from neat or blended biodiesel has a higher mutagenic potency than that one of ULSD. Further research is needed to investigate the health effect of biodiesel as well as efficiency of DOC or other exhaust aftertreatment systems. PMID:26457185

Transient and Steady-state Tests of the Space Power Research Engine with Resistive and Motor Loads

NASA Technical Reports Server (NTRS)

Rauch, Jeffrey S.; Kankam, M. David

1995-01-01

The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

Transient and steady-state tests of the space power research engine with resistive and motor loads

NASA Astrophysics Data System (ADS)

Rauch, Jeffrey S.; Kankam, M. David

1995-01-01

The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

Study on the combustion process in a modern diesel engine controlled by pre-injection strategy

NASA Astrophysics Data System (ADS)

Punov, P.; Milkov, N.; Perilhon, C.; Podevin, P.; Evtimov, T.

2017-10-01

The paper aims to study the combustion process in a modern diesel engine over the engine operating map. In order to study the rate of heat release (ROHR), an automotive diesel engine was experimentally tested using the injection parameters factory defined. The experimental test was conducted over the engine operating map as the engine speed was limited to 2400 rpm. Then, an engine simulation model was developed in AVL Boost. By means of that model the ROHR was estimated and approximated by means of double Vibe function. In all engine operating points we found two peaks at the ROHR. The first is a result of the pilot injection as the second corresponds to the main injection. There was not found an overlap between both peaks. It was found that the first peak of ROHR occurs closely before top dead center (BTDC) at partial load than full load. The ROHR peak as a result of main injection begins from 4°BTDC to 18°ATDC. It starts earlier with increasing engine speed and load. The combustion duration varies from 30 ºCA to 70 °CA. In order to verify the results pressure curve was estimated by means of defined Vibe function parameters and combustion duration. As a result, we observed small deviation between measured and simulated pressure curves.

Ultrafine particle emission characteristics of diesel engine by on-board and test bench measurement.

PubMed

Huang, Cheng; Lou, Diming; Hu, Zhiyuan; Tan, Piqiang; Yao, Di; Hu, Wei; Li, Peng; Ren, Jin; Chen, Changhong

2012-01-01

This study investigated the emission characteristics of ultrafine particles based on test bench and on-board measurements. The bench test results showed the ultrafine particle number concentration of the diesel engine to be in the range of (0.56-8.35) x 10(8) cm(-3). The on-board measurement results illustrated that the ultrafine particles were strongly correlated with changes in real-world driving cycles. The particle number concentration was down to 2.0 x 10(6) cm(-3) and 2.7 x 10(7) cm(-3) under decelerating and idling operations and as high as 5.0 x 10(8) cm(-3) under accelerating operation. It was also indicated that the particle number measured by the two methods increased with the growth of engine load at each engine speed in both cases. The particle number presented a "U" shaped distribution with changing speed at high engine load conditions, which implies that the particle number will reach its lowest level at medium engine speeds. The particle sizes of both measurements showed single mode distributions. The peak of particle size was located at about 50-80 nm in the accumulation mode particle range. Nucleation mode particles will significantly increase at low engine load operations like idling and decelerating caused by the high concentration of unburned organic compounds.

The effects of emission control strategies on light-absorbing carbon emissions from a modern heavy-duty diesel engine.

PubMed

Robinson, Michael A; Olson, Michael R; Liu, Z Gerald; Schauer, James J

2015-06-01

Control of atmospheric black carbon (BC) and brown carbon (BrC) has been proposed as an important pathway to climate change mitigation, but sources of BC and BrC are still not well understood. In order to better identify the role of modern heavy-duty diesel engines on the production of BC and BrC, emissions from a heavy-duty diesel engine operating with different emission control strategies were examined using a source dilution sampling system. The effect of a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) on light-absorbing carbon (LAC) was evaluated at three steady-state engine operation modes: idle, 50% speed and load, and 100% speed and load. LAC was measured with four different engine configurations: engine out, DOC out, DPF out, and engine out with an altered combustion calibration. BC and BrC emission rates were measured with the Aethalometer (AE-31). EC and BC emission rates normalized to the mass of CO₂emitted increased with increasing engine speed and load. Emission rates normalized to brake-specific work did not exhibit similar trends with speed and load, but rather the highest emission rate was measured at idle. EC and OC emissions were reduced by 99% when the DOC and DPF architecture was applied. The application of a DPF was equally effective at removing 99% of the BC fraction of PM, proving to be an important control strategy for both LAC and PM. BC emissions were unexpectedly increased across the DOC, seemingly due to a change aerosol optical properties. Removal of exhaust gas recirculation (EGR) flow due to simulated EGR cooler failure caused a large increase in OC and BrC emission rates at idle, but had limited influence during high load operation. LAC emissions proved to be sensitive to the same control strategies effective at controlling the total mass of diesel PM. In the context of black carbon emissions, very small emission rates of brown carbon were measured over a range of control technologies and engine operating conditions. During specific idle engine operation without EGR and adjusted fueling conditions, brown carbon can be formed in significant amounts, requiring careful management tactics. Control technologies for particulate matter are very effective for light-absorbing carbon, reducing black carbon emissions to near zero for modern engines equipped with a DPF. Efforts to control atmospheric brown carbon need to focus on other sources other than modern diesel engines, such as biomass burning.

Controllability of Free-piston Stirling Engine/linear Alternator Driving a Dynamic Load

NASA Technical Reports Server (NTRS)

Kankam, M. David; Rauch, Jeffrey S.

1994-01-01

This paper presents the dynamic behavior of a Free-Piston Stirling Engine/linear alternator (FPSE/LA) driving a single-phase fractional horse-power induction motor. The controllability and dynamic stability of the system are discussed by means of sensitivity effects of variations in system parameters, engine controller, operating conditions, and mechanical loading on the induction motor. The approach used expands on a combined mechanical and thermodynamic formulation employed in a previous paper. The application of state-space technique and frequency domain analysis enhances understanding of the dynamic interactions. Engine-alternator parametric sensitivity studies, similar to those of the previous paper, are summarized. Detailed discussions are provided for parametric variations which relate to the engine controller and system operating conditions. The results suggest that the controllability of a FPSE-based power system is enhanced by proper operating conditions and built-in controls.

Detailed characterization of particulate matter emitted by lean-burn gasoline direct injection engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zelenyuk, Alla; Wilson, Jacqueline; Imre, Dan

This study presents detailed characterization of the chemical and physical properties of PM emitted by a 2.0L BMW lean-burn turbocharged GDI engine operated under a number of combustion strategies that include lean homogeneous, lean stratified, stoichiometric, and fuel rich conditions. We characterized PM number concentrations, size distributions, and the size, mass, compositions, and effective density of fractal and compact individual exhaust particles. For the fractal particles, these measurements yielded fractal dimension, average diameter of primary spherules, and number of spherules, void fraction, and dynamic shape factors as function of particle size. Overall, the PM properties were shown to vary significantlymore » with engine operation condition. Lean stratified operation yielded the most diesel-like size distribution and the largest PM number and mass concentrations, with nearly all particles being fractal agglomerates composed of elemental carbon with small amounts of ash and organics. In contrast, stoichiometric operation yielded a larger fraction of ash particles, especially at low speed and low load. Three distinct forms of ash particles were observed, with their fractions strongly dependent on engine operating conditions: sub-50 nm ash particles, abundant at low speed and low load, ash-containing fractal particles, and large compact ash particles that significantly contribute to PM mass loadings« less

Impact of air conditioning system operation on increasing gases emissions from automobile

NASA Astrophysics Data System (ADS)

Burciu, S. M.; Coman, G.

2016-08-01

The paper presents a study concerning the influence of air conditioning system operation on the increase of gases emissions from cars. The study focuses on urban operating regimes of the automobile, regimes when the engines have low loads or are operating at idling. Are presented graphically the variations of pollution emissions (CO, CO2, HC) depending of engine speed and the load on air conditioning system. Additionally are presented, injection duration, throttle position, the mechanical power required by the compressor of air conditioning system and the refrigerant pressure variation on the discharge path, according to the stage of charging of the air conditioning system.

Effect of engine load and biogas flow rate to the performance of a compression ignition engine run in dual-fuel (dieselbiogas) mode

NASA Astrophysics Data System (ADS)

Ambarita, H.

2018-02-01

The Government of Indonesia (GoI) has released a target on reduction Green Houses Gases emissions (GHG) by 26% from level business-as-usual by 2020, and the target can be up to 41% by international supports. In the energy sector, this target can be reached effectively by promoting fossil fuel replacement or blending with biofuel. One of the potential solutions is operating compression ignition (CI) engine in dual-fuel (diesel-biogas) mode. In this study effects of engine load and biogas flow rate on the performance and exhaust gas emissions of a compression ignition engine run in dual-fuel mode are investigated. In the present study, the used biogas is refined with methane content 70% of volume. The objectives are to explore the optimum operating condition of the CI engine run in dual-fuel mode. The experiments are performed on a four-strokes CI engine with rated output power of 4.41 kW. The engine is tested at constant speed 1500 rpm. The engine load varied from 600W to 1500W and biogas flow rate varied from 0 L/min to 6 L/min. The results show brake thermal efficiency of the engine run in dual-fuel mode is better than pure diesel mode if the biogas flow rates are 2 L/min and 4 L/min. It is recommended to operate the present engine in a dual-fuel mode with biogas flow rate of 4 L/min. The consumption of diesel fuel can be replaced up to 50%.

Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, Reed; Ickes, Andrew; Wallner, Thomas

2015-01-01

Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection of a higher reactivity fuel, otherwise known as Reactivity Controlled Compression Ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on a 13Lmore » multi-cylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and direct injection of diesel fuel. Engine testing was conducted at an engine speed of 1200 RPM over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study. The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection quantity was reduced to keep peak cylinder pressure and maximum pressure rise rate under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar BMEP with a peak brake thermal efficiency of 47.6%.« less

NREL: News - Prototype Low-Emissions Natural Gas Engine Saves Fuel

Science.gov Websites

/heavy_vehicle/natgas_pub.html#engine for a copy of the full NREL report, "Development of a Throttleless engines. In testing, the prototype engine operated over the full speed and load range, delivering 250

Photochemical processing of diesel fuel emissions as a large secondary source of isocyanic acid (HNCO)

NASA Astrophysics Data System (ADS)

Link, M. F.; Friedman, B.; Fulgham, R.; Brophy, P.; Galang, A.; Jathar, S. H.; Veres, P.; Roberts, J. M.; Farmer, D. K.

2016-04-01

Isocyanic acid (HNCO) is a well-known air pollutant that affects human health. Biomass burning, smoking, and combustion engines are known HNCO sources, but recent studies suggest that secondary production in the atmosphere may also occur. We directly observed photochemical production of HNCO from the oxidative aging of diesel exhaust during the Diesel Exhaust Fuel and Control experiments at Colorado State University using acetate ionization time-of-flight mass spectrometry. Emission ratios of HNCO were enhanced, after 1.5 days of simulated atmospheric aging, from 50 to 230 mg HNCO/kg fuel at idle engine operating conditions. Engines operated at higher loads resulted in less primary and secondary HNCO formation, with emission ratios increasing from 20 to 40 mg HNCO/kg fuel under 50% load engine operating conditions. These results suggest that photochemical sources of HNCO could be more significant than primary sources in urban areas.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalaskar, Vickey B; Szybist, James P; Splitter, Derek A

In recent years a number of studies have demonstrated that boosted operation combined with external EGR is a path forward for expanding the high load limit of homogeneous charge compression ignition (HCCI) operation with the negative valve overlap (NVO) valve strategy. However, the effects of fuel composition with this strategy have not been fully explored. In this study boosted HCCI combustion is investigated in a single-cylinder research engine equipped with direct injection (DI) fueling, cooled external exhaust gas recirculation (EGR), laboratory pressurized intake air, and a fully-variable hydraulic valve actuation (HVA) valve train. Three fuels with significant compositional differences aremore » investigated: regular grade gasoline (RON = 90.2), 30% ethanol-gasoline blend (E30, RON = 100.3), and 24% iso-butanol-gasoline blend (IB24, RON = 96.6). Results include engine loads from 350 to 800 kPa IMEPg for all fuels at three engine speeds 1600, 2000, and 2500 rpm. All operating conditions achieved thermal efficiency (gross indicated efficiency) between 38 and 47%, low NOX emissions ( 0.1 g/kWh), and high combustion efficiency ( 96.5%). Detailed sweeps of intake manifold pressure (atmospheric to 250 kPaa), EGR (0 25% EGR), and injection timing are conducted to identify fuel-specific effects. The major finding of this study is that while significant fuel compositional differences exist, in boosted HCCI operation only minor changes in operational conditions are required to achieve comparable operation for all fuels. In boosted HCCI operation all fuels were able to achieve matched load-speed operation, whereas in conventional SI operation the fuel-specific knock differences resulted in significant differences in the operable load-speed space. Although all fuels were operable in boosted HCCI, the respective air handling requirements are also discussed, including an analysis of the demanded turbocharger efficiency.« less

Effect of steady flight loads on JT9D-7 performance deterioration

NASA Technical Reports Server (NTRS)

Jay, A.; Todd, E. S.

1978-01-01

Short term engine deterioration occurs in less than 250 flights on a new engine and in the first flights following engine repair; while long term deterioration involves primarily hot section distress and compression system losses which occur at a somewhat slower rate. The causes for short-term deterioration are associated with clearance changes which occur in the flight environment. Analytical techniques utilized to examine the effects of flight loads and engine operating conditions on performance deterioration are presented. The role of gyroscopic, gravitational, and aerodynamic loads are discussed along with the effect of variations in engine build clearances. These analytical results are compared to engine test data along with the correlation between analytically predicted and measured clearances and rub patterns. Conclusions are drawn and important issues are discussed.

Composite load spectra for select space propulsion structural components

NASA Technical Reports Server (NTRS)

Newell, J. F.; Ho, H. W.; Kurth, R. E.

1991-01-01

The work performed to develop composite load spectra (CLS) for the Space Shuttle Main Engine (SSME) using probabilistic methods. The three methods were implemented to be the engine system influence model. RASCAL was chosen to be the principal method as most component load models were implemented with the method. Validation of RASCAL was performed. High accuracy comparable to the Monte Carlo method can be obtained if a large enough bin size is used. Generic probabilistic models were developed and implemented for load calculations using the probabilistic methods discussed above. Each engine mission, either a real fighter or a test, has three mission phases: the engine start transient phase, the steady state phase, and the engine cut off transient phase. Power level and engine operating inlet conditions change during a mission. The load calculation module provides the steady-state and quasi-steady state calculation procedures with duty-cycle-data option. The quasi-steady state procedure is for engine transient phase calculations. In addition, a few generic probabilistic load models were also developed for specific conditions. These include the fixed transient spike model, the poison arrival transient spike model, and the rare event model. These generic probabilistic load models provide sufficient latitude for simulating loads with specific conditions. For SSME components, turbine blades, transfer ducts, LOX post, and the high pressure oxidizer turbopump (HPOTP) discharge duct were selected for application of the CLS program. They include static pressure loads and dynamic pressure loads for all four components, centrifugal force for the turbine blade, temperatures of thermal loads for all four components, and structural vibration loads for the ducts and LOX posts.

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 time (experimental or modeling based), a new fuel’s acceptability in a conventional engine could be assessed by determining that the total ignition delay is not too short or too long.« less

Experimental and Analytical Determination of the Motion of Hydraulically Operated Valve Stems in Oil Engine Injection Systems

NASA Technical Reports Server (NTRS)

Gelalles, A G; Rothrock, A M

1930-01-01

This research on the pressure variations in the injection system of the N.A.C.A. Spray Photography Equipment and on the effects of these variations on the motion of the timing valve stem was undertaken in connection with the study of fuel injection systems for high-speed oil engines. The methods of analysis of the pressure variations and the general equation for the motion of the spring-loaded stem for the timing valve are applicable to a spring-loaded automatic injection valve, and in general to all hydraulically operated valves. A sample calculation for a spring-loaded automatic injection valve is included.

Overview of aerothermodynamic loads definition study

NASA Technical Reports Server (NTRS)

Gaugler, Raymond E.

1991-01-01

The objective of the Aerothermodynamic Loads Definition Study is to develop methods of accurately predicting the operating environment in advanced Earth-to-Orbit (ETO) propulsion systems, such as the Space Shuttle Main Engine (SSME) powerhead. Development of time averaged and time dependent three dimensional viscous computer codes as well as experimental verification and engine diagnostic testing are considered to be essential in achieving that objective. Time-averaged, nonsteady, and transient operating loads must all be well defined in order to accurately predict powerhead life. Described here is work in unsteady heat flow analysis, improved modeling of preburner flow, turbulence modeling for turbomachinery, computation of three dimensional flow with heat transfer, and unsteady viscous multi-blade row turbine analysis.

Experimental investigation of regulated and unregulated emissions from a diesel engine fueled with Euro V diesel fuel and fumigation methanol

NASA Astrophysics Data System (ADS)

Zhang, Z. H.; Cheung, C. S.; Chan, T. L.; Yao, C. D.

2010-03-01

Experiments were conducted on a four-cylinder direct-injection diesel engine with part of the engine load taken up by fumigation methanol injected into the air intake of each cylinder to investigate the regulated and unregulated gaseous emissions and particulate emission of the engine under five engine loads at an engine speed of 1920 rev min -1. The fumigation methanol was injected to top up 10%, 20% and 30% of the engine load under different engine operating conditions. The experimental results show that at low engine loads, the brake thermal efficiency (BTE) decreases with increase in fumigation methanol; but at high engine loads, the BTE is not significantly affected by fumigation methanol. The fumigation methanol results in significant increase in hydrocarbon (HC), carbon monoxide (CO) and nitrogen dioxide (NO 2) emissions, but decrease in nitrogen oxides (NO x). For the unregulated gaseous emissions, unburned methanol, formaldehyde and BTX (benzene, toluene and xylene) emissions increase but ethyne, ethene and 1,3-butadiene emissions decrease. Particulate mass and number concentrations also decrease with increase in fumigation methanol. A diesel oxidation catalyst (DOC) is found to reduce significantly most of the pollutants, including the air toxics, when the exhaust gas temperature is sufficiently high.

Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, Reed; Ickes, Andrew; Wallner, Thomas

Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection (DI) of a higher reactivity fuel, otherwise known as reactivity controlled compression ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on amore » 13 l multicylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and DI of diesel fuel. Engine testing was conducted at an engine speed of 1200 rpm over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study. The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion (CDC) and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection (PFI) quantity was reduced to keep peak cylinder pressure (PCP) and maximum pressure rise rate (MPRR) under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar brake mean effective pressure (BMEP) with a peak brake thermal efficiency (BTE) of 47.6%.« less

40 CFR 1065.510 - Engine mapping.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the warm-up until the engine coolant, block, or head absolute temperature is within ± 2% of its mean... demand to minimum, use the dynamometer or other loading device to target a torque of zero on the engine's...-speed governor, operate the engine at warm idle speed and zero torque on the engine's primary output...

Effects of Gasoline Direct Injection Engine Operating Parameters on Particle Number Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, X.; Ratcliff, M. A.; Zigler, B. T.

2012-04-19

A single-cylinder, wall-guided, spark ignition direct injection engine was used to study the impact of engine operating parameters on engine-out particle number (PN) emissions. Experiments were conducted with certification gasoline and a splash blend of 20% fuel grade ethanol in gasoline (E20), at four steady-state engine operating conditions. Independent engine control parameter sweeps were conducted including start of injection, injection pressure, spark timing, exhaust cam phasing, intake cam phasing, and air-fuel ratio. The results show that fuel injection timing is the dominant factor impacting PN emissions from this wall-guided gasoline direct injection engine. The major factor causing high PN emissionsmore » is fuel liquid impingement on the piston bowl. By avoiding fuel impingement, more than an order of magnitude reduction in PN emission was observed. Increasing fuel injection pressure reduces PN emissions because of smaller fuel droplet size and faster fuel-air mixing. PN emissions are insensitive to cam phasing and spark timing, especially at high engine load. Cold engine conditions produce higher PN emissions than hot engine conditions due to slower fuel vaporization and thus less fuel-air homogeneity during the combustion process. E20 produces lower PN emissions at low and medium loads if fuel liquid impingement on piston bowl is avoided. At high load or if there is fuel liquid impingement on piston bowl and/or cylinder wall, E20 tends to produce higher PN emissions. This is probably a function of the higher heat of vaporization of ethanol, which slows the vaporization of other fuel components from surfaces and may create local fuel-rich combustion or even pool-fires.« less

Autonomous Cryogenics Loading Operations Simulation Software: Knowledgebase Autonomous Test Engineer

NASA Technical Reports Server (NTRS)

Wehner, Walter S.

2012-01-01

The Simulation Software, KATE (Knowledgebase Autonomous Test Engineer), is used to demonstrate the automatic identification of faults in a system. The ACLO (Autonomous Cryogenics Loading Operation) project uses KATE to monitor and find faults in the loading of the cryogenics int o a vehicle fuel tank. The KATE software interfaces with the IHM (Integrated Health Management) systems bus to communicate with other systems that are part of ACLO. One system that KATE uses the IHM bus to communicate with is AIS (Advanced Inspection System). KATE will send messages to AIS when there is a detected anomaly. These messages include visual inspection of specific valves, pressure gauges and control messages to have AIS open or close manual valves. My goals include implementing the connection to the IHM bus within KATE and for the AIS project. I will also be working on implementing changes to KATE's Ul and implementing the physics objects in KATE that will model portions of the cryogenics loading operation.

Generator voltage stabilisation for series-hybrid electric vehicles.

PubMed

Stewart, P; Gladwin, D; Stewart, J; Cowley, R

2008-04-01

This paper presents a controller for use in speed control of an internal combustion engine for series-hybrid electric vehicle applications. Particular reference is made to the stability of the rectified DC link voltage under load disturbance. In the system under consideration, the primary power source is a four-cylinder normally aspirated gasoline internal combustion engine, which is mechanically coupled to a three-phase permanent magnet AC generator. The generated AC voltage is subsequently rectified to supply a lead-acid battery, and permanent magnet traction motors via three-phase full bridge power electronic inverters. Two complementary performance objectives exist. Firstly to maintain the internal combustion engine at its optimal operating point, and secondly to supply a stable 42 V supply to the traction drive inverters. Achievement of these goals minimises the transient energy storage requirements at the DC link, with a consequent reduction in both weight and cost. These objectives imply constant velocity operation of the internal combustion engine under external load disturbances and changes in both operating conditions and vehicle speed set-points. An electronically operated throttle allows closed loop engine velocity control. System time delays and nonlinearities render closed loop control design extremely problematic. A model-based controller is designed and shown to be effective in controlling the DC link voltage, resulting in the well-conditioned operation of the hybrid vehicle.

Feasibility of CO/sub 2/ monitoring to assess air quality in mines using diesel equipment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, J.H. Jr.

1987-01-01

The methodology includes: (1) establishing pollutant to CO/sub 2/ ratios for in-service equipment, (2) estimating pollutant concentrations from the ratios and in-mine CO/sub 2/ measurements, and (3) using an air quality index to combine the pollutants into a single number, which indicates the health hazard associated with the pollutants. For the methodology to be valid, the pollutant to CO/sub 2/ ratios must remain constant if engine operating conditions do not significantly change. However, due to the complex dynamics of the fuel injection system, the fuel-air combustion process, and the engine speed-load governing system, the pollutant to CO/sub 2/ ratios maymore » vary during repetitive, but transient engine speed-and-load operation. These transient effects were investigated. In addition, the influence of changing engine conditions due to engine maladjustment, and a practical means to evaluate engine condition were investigated to advance the methodology. The laboratory investigation determined that CO/sub 2/ is an effective indicator of engine exhaust pollutants. It was shown that the exhaust concentrations of carbon monoxide, carbon dioxide, oxides of nitrogen, hydrocarbons, and particulate matter do not significantly vary among repetitive, but transient engine speed-and-load duty cycles typical of in-service equipment. Based on an air quality index and threshold limit values, particulate matter exhibited the greatest adverse effect on air quality. Particulate mass was separated into volatile (organic soluble fraction) and nonvolatile (insoluble carbon fraction) components. Due to particulate concentrations, the engine operating conditions of overfueling and advanced injector timing had greater adverse effects on air quality than the conditions of retarded injector timing, intake air restriction, and Federal certification specifications.« less

14 CFR 25.365 - Pressurized compartment loads.

Code of Federal Regulations, 2011 CFR

2011-01-01

... multiplied by a factor of 1.33 for airplanes to be approved for operation to 45,000 feet or by a factor of 1.67 for airplanes to be approved for operation above 45,000 feet, omitting other loads. (e) Any... an engine disintegration; (2) Any opening in any pressurized compartment up to the size Ho in square...

Filter-based control of particulate matter from a lean gasoline direct injection engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parks, II, James E; Lewis Sr, Samuel Arthur; DeBusk, Melanie Moses

New regulations requiring increases in vehicle fuel economy are challenging automotive manufacturers to identify fuel-efficient engines for future vehicles. Lean gasoline direct injection (GDI) engines offer significant increases in fuel efficiency over the more common stoichiometric GDI engines already in the marketplace. However, particulate matter (PM) emissions from lean GDI engines, particularly during stratified combustion modes, are problematic for lean GDI technology to meet U.S. Environmental Protection Agency Tier 3 and other future emission regulations. As such, the control of lean GDI PM with wall-flow filters, referred to as gasoline particulate filter (GPF) technology, is of interest. Since lean GDImore » PM chemistry and morphology differ from diesel PM (where more filtration experience exists), the functionality of GPFs needs to be studied to determine the operating conditions suitable for efficient PM removal. In addition, lean GDI engine exhaust temperatures are generally higher than diesel engines which results in more continuous regeneration of the GPF and less presence of the soot cake layer common to diesel particulate filters. Since the soot layer improves filtration efficiency, this distinction is important to consider. Research on the emission control of PM from a lean GDI engine with a GPF was conducted on an engine dynamometer. PM, after dilution, was characterized with membrane filters, organic vs. elemental carbon characterization, and size distribution techniques at various steady state engine speed and load points. The engine was operated in three primary combustion modes: stoichiometric, lean homogeneous, and lean stratified. In addition, rich combustion was utilized to simulate PM from engine operation during active regeneration of lean NOx control technologies. High (>95%) PM filtration efficiencies were observed over a wide range of conditions; however, some PM was observed to slip through the GPF at high speed and load conditions. The PM characterization at various engine speeds and loads will help enable optimized GPF design and control to achieve more fuel efficient lean GDI vehicles with low PM emissions.« less

40 CFR 90.404 - Test procedure overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust... engine operating conditions to be conducted on an engine dynamometer or equivalent load and speed... also designed to determine the brake-specific emissions of non-methane hydrocarbons. The test consists...

40 CFR 90.404 - Test procedure overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust... engine operating conditions to be conducted on an engine dynamometer or equivalent load and speed... also designed to determine the brake-specific emissions of non-methane hydrocarbons. The test consists...

40 CFR 90.404 - Test procedure overview.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust... engine operating conditions to be conducted on an engine dynamometer or equivalent load and speed... also designed to determine the brake-specific emissions of non-methane hydrocarbons. The test consists...

40 CFR 90.404 - Test procedure overview.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust... engine operating conditions to be conducted on an engine dynamometer or equivalent load and speed... also designed to determine the brake-specific emissions of non-methane hydrocarbons. The test consists...

Sources of variance in BC mass measurements from a small marine engine: Influence of the instruments, fuels and loads

NASA Astrophysics Data System (ADS)

Jiang, Yu; Yang, Jiacheng; Gagné, Stéphanie; Chan, Tak W.; Thomson, Kevin; Fofie, Emmanuel; Cary, Robert A.; Rutherford, Dan; Comer, Bryan; Swanson, Jacob; Lin, Yue; Van Rooy, Paul; Asa-Awuku, Akua; Jung, Heejung; Barsanti, Kelley; Karavalakis, Georgios; Cocker, David; Durbin, Thomas D.; Miller, J. Wayne; Johnson, Kent C.

2018-06-01

Knowledge of black carbon (BC) emission factors from ships is important from human health and environmental perspectives. A study of instruments measuring BC and fuels typically used in marine operation was carried out on a small marine engine. Six analytical methods measured the BC emissions in the exhaust of the marine engine operated at two load points (25% and 75%) while burning one of three fuels: a distillate marine (DMA), a low sulfur, residual marine (RMB-30) and a high-sulfur residual marine (RMG-380). The average emission factors with all instruments increased from 0.08 to 1.88 gBC/kg fuel in going from 25 to 75% load. An analysis of variance (ANOVA) tested BC emissions against instrument, load, and combined fuel properties and showed that both engine load and fuels had a statistically significant impact on BC emission factors. While BC emissions were impacted by the fuels used, none of the fuel properties investigated (sulfur content, viscosity, carbon residue and CCAI) was a primary driver for BC emissions. Of the two residual fuels, RMB-30 with the lower sulfur content, lower viscosity and lower residual carbon, had the highest BC emission factors. BC emission factors determined with the different instruments showed a good correlation with the PAS values with correlation coefficients R2 >0.95. A key finding of this research is the relative BC measured values were mostly independent of load and fuel, except for some instruments in certain fuel and load combinations.

Realization of station for testing asynchronous three-phase motors

NASA Astrophysics Data System (ADS)

Wróbel, A.; Surma, W.

2016-08-01

Nowadays, you cannot imagine the construction and operation of machines without the use of electric motors [13-15]. The proposed position is designed to allow testing of asynchronous three-phase motors. The position consists of a tested engine and the engine running as a load, both engines combined with a mechanical clutch [2]. The value of the load is recorded by measuring shaft created with Strain Gauge Bridge. This concept will allow to study the basic parameters of the engines, visualization motor parameters both vector and scalar controlled, during varying load drive system. In addition, registration during the variable physical parameters of the working electric motor, controlled by a frequency converter or controlled by a contactor will be possible. Position is designed as a teaching and research position to characterize the engines. It will be also possible selection of inverter parameters.

Expanded study of feasibility of measuring in-flight 747/JT9D loads, performance, clearance, and thermal data

NASA Technical Reports Server (NTRS)

Sallee, G. P.; Martin, R. L.

1980-01-01

The JT9D jet engine exhibits a TSFC loss of about 1 percent in the initial 50 flight cycles of a new engine. These early losses are caused by seal-wear induced opening of running clearances in the engine gas path. The causes of this seal wear have been identified as flight induced loads which deflect the engine cases and rotors, causing the rotating blades to rub against the seal surfaces, producing permanent clearance changes. The real level of flight loads encountered during airplane acceptance testing and revenue service and the engine's response in the dynamic flight environment were investigated. The feasibility of direct measurement of these flight loads and their effects by concurrent measurement of 747/JT9D propulsion system aerodynamic and inertia loads and the critical engine clearance and performance changes during 747 flight and ground operations was evaluated. A number of technical options were examined in relation to the total estimated program cost to facilitate selection of the most cost effective option. It is concluded that a flight test program meeting the overall objective of determining the levels of aerodynamic and inertia load levels to which the engine is exposed during the initial flight acceptance test and normal flight maneuvers is feasible and desirable. A specific recommended flight test program, based on the evaluation of cost effectiveness, is defined.

40 CFR 1039.505 - How do I test engines using steady-state duty cycles, including ramped-modal testing?

Code of Federal Regulations, 2011 CFR

2011-07-01

.... You may extend the sampling time to improve measurement accuracy of PM emissions, using good...-speed engines whose design prevents full-load operation for extended periods, you may ask for approval... designed to operate for extended periods. (e) See 40 CFR part 1065 for detailed specifications of...

JT9D performance deterioration results from a simulated aerodynamic load test

NASA Technical Reports Server (NTRS)

Stakolich, E. G.; Stromberg, W. J.

1981-01-01

The results of testing to identify the effects of simulated aerodynamic flight loads on JT9D engine performance are presented. The test results were also used to refine previous analytical studies on the impact of aerodynamic flight loads on performance losses. To accomplish these objectives, a JT9D-7AH engine was assembled with average production clearances and new seals as well as extensive instrumentation to monitor engine performance, case temperatures, and blade tip clearance changes. A special loading device was designed and constructed to permit application of known moments and shear forces to the engine by the use of cables placed around the flight inlet. The test was conducted in the Pratt & Whitney Aircraft X-Ray Test Facility to permit the use of X-ray techniques in conjunction with laser blade tip proximity probes to monitor important engine clearance changes. Upon completion of the test program, the test engine was disassembled, and the condition of gas path parts and final clearances were documented. The test results indicate that the engine lost 1.1 percent in thrust specific fuel consumption (TSFC), as measured under sea level static conditions, due to increased operating clearances caused by simulated flight loads. This compares with 0.9 percent predicted by the analytical model and previous study efforts.

Emission reduction from diesel engine using fumigation methanol and diesel oxidation catalyst.

PubMed

Zhang, Z H; Cheung, C S; Chan, T L; Yao, C D

2009-07-15

This study is aimed to investigate the combined application of fumigation methanol and a diesel oxidation catalyst for reducing emissions of an in-use diesel engine. Experiments were performed on a 4-cylinder naturally-aspirated direct-injection diesel engine operating at a constant speed of 1800 rev/min for five engine loads. The experimental results show that at low engine loads, the brake thermal efficiency decreases with increase in fumigation methanol; but at high loads, it slightly increases with increase in fumigation methanol. The fumigation method results in a significant increase in hydrocarbon (HC), carbon monoxide (CO), and nitrogen dioxide (NO(2)) emissions, but decrease in nitrogen oxides (NO(x)), smoke opacity and the particulate mass concentration. For the submicron particles, the total number of particles decreases. In all cases, there is little change in geometrical mean diameter of the particles. After catalytic conversion, the HC, CO, NO(2), particulate mass and particulate number concentrations were significantly reduced at medium to high engine loads; while the geometrical mean diameter of the particles becomes larger. Thus, the combined use of fumigation methanol and diesel oxidation catalyst leads to a reduction of HC, CO, NO(x), particulate mass and particulate number concentrations at medium to high engine loads.

Diesel Engine With Air Boosted Turbocharger

DTIC Science & Technology

2010-05-26

of the exhaust turbocharger over the entire RPM range of the internal combustion engine . To this end, the...Kriegler, discloses that in order to utilize recycling of exhaust gases at high engine loads in an internal- combustion engine with an exhaust gas...October 29, 2002) to Cook, discloses an apparatus for and method of exhaust gas recirculation in an internal combustion engine that operates

Control of the low-load region in partially premixed combustion

NASA Astrophysics Data System (ADS)

Ingesson, Gabriel; Yin, Lianhao; Johansson, Rolf; Tunestal, Per

2016-09-01

Partially premixed combustion (PPC) is a low temperature, direct-injection combustion concept that has shown to give promising emission levels and efficiencies over a wide operating range. In this concept, high EGR ratios, high octane-number fuels and early injection timings are used to slow down the auto-ignition reactions and to enhance the fuel and are mixing before the start of combustion. A drawback with this concept is the combustion stability in the low-load region where a high octane-number fuel might cause misfire and low combustion efficiency. This paper investigates the problem of low-load PPC controller design for increased engine efficiency. First, low-load PPC data, obtained from a multi-cylinder heavy- duty engine is presented. The data shows that combustion efficiency could be increased by using a pilot injection and that there is a non-linearity in the relation between injection and combustion timing. Furthermore, intake conditions should be set in order to avoid operating points with unfavourable global equivalence ratio and in-cylinder temperature combinations. Model predictive control simulations were used together with a calibrated engine model to find a gas-system controller that fulfilled this task. The findings are then summarized in a suggested engine controller design. Finally, an experimental performance evaluation of the suggested controller is presented.

The Waukesha Turbocharger Control Module: A tool for improved engine efficiency and response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zurlo, J.R.; Reinbold, E.O.; Mueller, J.

1996-12-31

The Waukesha Turbocharger Control Module allows optimum control of turbochargers on lean burn gaseous fueled engines. The Turbocharger Control Module is user programmed to provide either maximum engine efficiency or best engine response to load changes. In addition, the Turbocharger Control Module prevents undesirable turbocharger surge. The Turbocharger Control Module consists of an electronic control box, engine speed, intake manifold pressure, ambient temperature sensors, and electric actuators driving compressor bypass and wastegate valves. The Turbocharger Control Module expands the steady state operational environment of the Waukesha AT27GL natural gas engine from sea level to 1,525 m altitude with one turbochargermore » match and improves the engine speed turn down by 80 RPM. Finally, the Turbocharger Control Module improves engine response to load changes.« less

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.

Dynamic analysis of Free-Piston Stirling Engine/Linear Alternator-load system-experimentally validated

NASA Technical Reports Server (NTRS)

Kankam, M. David; Rauch, Jeffrey S.; Santiago, Walter

1992-01-01

This paper discusses the effects of variations in system parameters on the dynamic behavior of the Free-Piston Stirling Engine/Linear Alternator (FPSE/LA)-load system. The mathematical formulations incorporate both the mechanical and thermodynamic properties of the FPSE, as well as the electrical equations of the connected load. A state-space technique in the frequency domain is applied to the resulting system of equations to facilitate the evaluation of parametric impacts on the system dynamic stability. Also included is a discussion on the system transient stability as affected by sudden changes in some key operating conditions. Some representative results are correlated with experimental data to verify the model and analytic formulation accuracies. Guidelines are given for ranges of the system parameters which will ensure an overall stable operation.

Dynamic analysis of free-piston Stirling engine/linear alternator-load system - Experimentally validated

NASA Technical Reports Server (NTRS)

Kankam, M. D.; Rauch, Jeffrey S.; Santiago, Walter

1992-01-01

This paper discusses the effects of a variations in system parameters on the dynamic behavior of a Free-Piston Stirling Engine/Linear Alternator (FPSE/LA)-load system. The mathematical formulations incorporates both the mechanical and thermodynamic properties of the FPSE, as well as the electrical equations of the connected load. State-space technique in the frequency domain is applied to the resulting system of equations to facilitate the evaluation of parametric impacts on the system dynamic stability. Also included is a discussion on the system transient stability as affected by sudden changes in some key operating conditions. Some representative results are correlated with experimental data to verify the model and analytic formulation accuracies. Guidelines are given for ranges of the system parameters which will ensure an overall stable operation.

Effect of timed secondary-air injection on automotive emissions

NASA Technical Reports Server (NTRS)

Coffin, K. P.

1973-01-01

A single cylinder of an automotive V-8 engine was fitted with an electronically timed system for the pulsed injection of secondary air. A straight-tube exhaust minimized any mixing other than that produced by secondary-air pulsing. The device was operated over a range of engine loads and speeds. Effects attributable to secondary-air pulsing were found, but emission levels were generally no better than using the engine's own injection system. Under nontypical fast-idle, no-load conditions, emission levels were reduced by roughly a factor of 2.

14 CFR 33.5 - Instruction manual for installing and operating the engine.

Code of Federal Regulations, 2013 CFR

2013-01-01

... devices, maintenance checks, and similar equipment or procedures that are outside the control of the... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES General § 33.5 Instruction manual for... attaching the engine to the aircraft, and the maximum allowable load for the mounting attachments and...

14 CFR 33.5 - Instruction manual for installing and operating the engine.

Code of Federal Regulations, 2014 CFR

2014-01-01

... devices, maintenance checks, and similar equipment or procedures that are outside the control of the... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES General § 33.5 Instruction manual for... attaching the engine to the aircraft, and the maximum allowable load for the mounting attachments and...

14 CFR 33.5 - Instruction manual for installing and operating the engine.

Code of Federal Regulations, 2011 CFR

2011-01-01

... devices, maintenance checks, and similar equipment or procedures that are outside the control of the... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES General § 33.5 Instruction manual for... attaching the engine to the aircraft, and the maximum allowable load for the mounting attachments and...

14 CFR 33.5 - Instruction manual for installing and operating the engine.

Code of Federal Regulations, 2012 CFR

2012-01-01

... devices, maintenance checks, and similar equipment or procedures that are outside the control of the... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES General § 33.5 Instruction manual for... attaching the engine to the aircraft, and the maximum allowable load for the mounting attachments and...

14 CFR 33.5 - Instruction manual for installing and operating the engine.

Code of Federal Regulations, 2010 CFR

2010-01-01

... devices, maintenance checks, and similar equipment or procedures that are outside the control of the... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES General § 33.5 Instruction manual for... attaching the engine to the aircraft, and the maximum allowable load for the mounting attachments and...

Influence of load and sliding velocity on wear resistance of solid-lubricant composites of ultra-high molecular weight polyethylene

NASA Astrophysics Data System (ADS)

Panin, S. V.; Kornienko, L. A.; Buslovich, D. G.; Alexenko, V. O.; Ivanova, L. R.

2017-12-01

To determine the limits of the operation loading intervals appropriate for the use of solid lubricant UHMWPE composites in tribounits for mechanical engineering and medicine, the tribotechnical properties of UHMWPE blends with the optimum solid lubricant filler content (polytetrafluoroethylene, calcium stearate, molybdenum disulfide, colloidal graphite, boron nitride) are studied under dry sliding friction at different velocities (V = 0.3 and 0.5 m/s) and loads (P = 60 and 140 N). It is shown that the wear resistance of solid lubricant UHMWPE composites at moderate sliding velocities (V = 0.3 m/s) and loads (P = 60 N) increases 2-3 times in comparison with pure UHMWPE, while at high load P = 140 N wear resistance of both neat UHMWPE and its composites is reduced almost twice. At high sliding velocities and loads (up to P = 140 N), multiple increasing of the wear of pure UHMWPE and its composites takes place (by the factor of 5 to 10). The operational conditions of UHMWPE composites in tribounits in engineering and medicine are discussed.

Microbial load monitor

NASA Technical Reports Server (NTRS)

Caplin, R. S.; Royer, E. R.

1978-01-01

Attempts are made to provide a total design of a Microbial Load Monitor (MLM) system flight engineering model. Activities include assembly and testing of Sample Receiving and Card Loading Devices (SRCLDs), operator related software, and testing of biological samples in the MLM. Progress was made in assembling SRCLDs with minimal leaks and which operate reliably in the Sample Loading System. Seven operator commands are used to control various aspects of the MLM such as calibrating and reading the incubating reading head, setting the clock and reading time, and status of Card. Testing of the instrument, both in hardware and biologically, was performed. Hardware testing concentrated on SRCLDs. Biological testing covered 66 clinical and seeded samples. Tentative thresholds were set and media performance listed.

Ceramic combustor mounting

DOEpatents

Hoffman, Melvin G.; Janneck, Frank W.

1982-01-01

A combustor for a gas turbine engine includes a metal engine block including a wall portion defining a housing for a combustor having ceramic liner components. A ceramic outlet duct is supported by a compliant seal on the metal block and a reaction chamber liner is stacked thereon and partly closed at one end by a ceramic bypass swirl plate which is spring loaded by a plurality of circumferentially spaced, spring loaded guide rods and wherein each of the guide rods has one end thereof directed exteriorly of a metal cover plate on the engine block to react against externally located biasing springs cooled by ambient air and wherein the rod spring support arrangement maintains the stacked ceramic components together so that a normal force is maintained on the seal between the outlet duct and the engine block under all operating conditions. The support arrangement also is operative to accommodate a substantial difference in thermal expansion between the ceramic liner components of the combustor and the metal material of the engine block.

Performance of a supercharged direct-injection stratified-charge rotary combustion engine

NASA Technical Reports Server (NTRS)

Bartrand, Timothy A.; Willis, Edward A.

1990-01-01

A zero-dimensional thermodynamic performance computer model for direct-injection stratified-charge rotary combustion engines was modified and run for a single rotor supercharged engine. Operating conditions for the computer runs were a single boost pressure and a matrix of speeds, loads and engine materials. A representative engine map is presented showing the predicted range of efficient operation. After discussion of the engine map, a number of engine features are analyzed individually. These features are: heat transfer and the influence insulating materials have on engine performance and exhaust energy; intake manifold pressure oscillations and interactions with the combustion chamber; and performance losses and seal friction. Finally, code running times and convergence data are presented.

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.

Decrease of dynamic loads in mobile energy means

NASA Astrophysics Data System (ADS)

Polivaev, O. I.; Gorban, L. K.; Vorohobin, A. V.; Vedrinsky, O. S.

2018-03-01

The increase in the productivity of machine and tractor units is possible due to the increase in operating speeds, this leads to the emergence of increased dynamic loads in the system “engine-transmission-propulsion unit-soil”, which worsens the performance of machine-tractor aggregates. To reduce fluctuations in the “engine-transmission” system, special vibration dampers are used, which installed in close proximity to the engine and protect well the transmission from uneven engine operation; however, such dampers practically do not eliminate the oscillations of external loads. Reducing dynamic loads on the transmission and the mobile power engine (MPE) is an important issue directly related to improving the performance, reliability and durability of the tractor, as well as reducing the slippage of the drive wheels. In order to reduce effectively dynamic loads on the transmission and on the MPE, it is necessary to introduce resilient damping elements closer to the sources of oscillations, namely, to the driving wheels. At the same time, the elastic-damping element should provide accumulation of vibration energy caused by external influences and have a large energy capacity. The installation of an elastic-damping element in the final link of the tractor transmission ensures a reduction in the magnitude of external influences, thereby protecting the engine and transmission from large dynamic loads, and allows one to reduce the slippage of the propellers, which has a positive effect on the traction and energy characteristics of the tractor. Traction tests of the LTP-55 tractor on a concrete road showed that the use of an elasto-damping drive makes it possible to increase the maximum tractive power from 33.5 to 35.3 kW and to reduce the slipping of propellers by 12-30%, the specific fuel consumption by 6-10%. When driving on stubble, the use of an elastic-damping drive increases the maximum tractive power from 25 to 26 kW, reduces the skidding of propellers by 10-28%, and the specific fuel consumption by 10-12.5%.

Structural dynamic analysis of the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Scott, L. P.; Jamison, G. T.; Mccutcheon, W. A.; Price, J. M.

1981-01-01

This structural dynamic analysis supports development of the SSME by evaluating components subjected to critical dynamic loads, identifying significant parameters, and evaluating solution methods. Engine operating parameters at both rated and full power levels are considered. Detailed structural dynamic analyses of operationally critical and life limited components support the assessment of engine design modifications and environmental changes. Engine system test results are utilized to verify analytic model simulations. The SSME main chamber injector assembly is an assembly of 600 injector elements which are called LOX posts. The overall LOX post analysis procedure is shown.

In-Plume Emission Test Stand 2: emission factors for 10- to 100-kW U.S. military generators.

PubMed

Zhu, Dongzi; Nussbaum, Nicholas J; Kuhns, Hampden D; Chang, M-C Oliver; Sodeman, David; Uppapalli, Sebastian; Moosmüller, Hans; Chow, Judith C; Watson, John G

2009-12-01

Although emissions of air pollutants from some military tactical equipment are not subject to the emissions standards, local communities near military bases must conform to the National Ambient Air Quality Standards. Military diesel generators are widely used in training. A portable in-plume system was used to measure fuel-based emission factors (EFs) for particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HCs) for 30-, 60-, and 100-kW generators at five load levels and for cold starts. It was found that EFs depend on multiple parameters including engine size, engine load, unit age, and total running hours. The average CO EF of generators tested was 5% lower, and the average NOx EF was 63% lower than AP-42 estimates; average PM EF was 80% less than the AP-42 estimates. A 2002 model-year 60-kW engine produced 25% less PM than a 1995 engine of the same family with similar running hours. CO EFs decrease with increasing engine load, NOx EFs increase up to mid-loads and decrease slightly at high loads, PM EFs increase with loads for 30- and 60-kW engines. CO and PM have higher EFs and NOx has a lower EF during cold starts than during hot-stabilized operation. PM chemical source profiles were also examined.

Characterisation of diesel particulate emission from engines using commercial diesel and biofuels

NASA Astrophysics Data System (ADS)

Ajtai, T.; Pintér, M.; Utry, N.; Kiss-Albert, G.; Gulyás, G.; Pusztai, P.; Puskás, R.; Bereczky, Á.; Szabados, Gy.; Szabó, G.; Kónya, Z.; Bozóki, Z.

2016-06-01

In this paper, the number concentration and the size distribution of diluted diesel exhaust particulate matter were measured at three different engine operating points in the speed-load range of the engine as follows: 1600 rpm; 50% load, 1900 rpm; 25% load, 1900 rpm; 75% load, adopted from the UN ECE Vehicle Regulation no. 49 (Revision 2) test protocol using pure diesel and biodiesel fuels, as well as their controlled blends. The emitted particulate assembly had lognormal size distribution in the accumulation mode regardless of the engine operational condition and the type of fuel. The total number and volume concentration emitted by the diesel engine decreased with increasing revolution per minute and rated torque in case of all the fuel types. The mixing ratio of the fuels did not linearly affect the total emission but had a minimum at 75% biodiesel content. We also studied the thermal evolution of the emitted particulates using a specially designed thermodenuder (TD) heated at specific temperatures (50 °C, 120 °C, and 250 °C). The first transition, when the temperature was increased from 50 °C to 120 °C resulted in lower number concentrations with small relative shifts of the peak position. However, in case of the second transition, when the temperature reached 250 °C the individual volatile particulates adsorbed onto the surface of soot particles were completely or partly vaporised resulting in lower total number concentrations with a substantial shift in peak position.

Airworthiness Qualification Criteria for Rotorcraft with External Sling Loads

NASA Technical Reports Server (NTRS)

Key, David L.

2002-01-01

This report presents the results of a study to develop airworthiness requirements for rotorcraft with external sling loads. The report starts with a review of the various phenomena that limit external sling load operations. Specifically discussed are the rotorcraft-load aeroservoelastic stability, load-on handling qualities, effects of automatic flight control system failure, load suspension system failure, and load stability at speed. Based on past experience and treatment of these phenomena, criteria are proposed to form a package for airworthiness qualification. The desired end objective is a set of operational flight envelopes for the rotorcraft with intended loads that can be provided to the user to guide operations in the field. The specific criteria proposed are parts of ADS-33E-PRF; MIL-F-9490D, and MIL-STD-913A all applied in the context of external sling loads. The study was performed for the Directorate of Engineering, U.S. Army Aviation and Missile Command (AMCOM), as part of the contract monitored by the Aerothermodynamics Directorate, U.S. Army AMCOM.

Foil Bearing Starting Considerations and Requirements for Rotorcraft Engine Applications

NASA Technical Reports Server (NTRS)

Radil, Kevin C.; DellaCorte, Christopher

2009-01-01

Foil gas bearings under development for rotorcraft-sized, hot core engine applications have been susceptible to damage from the slow acceleration and rates typically encountered during the pre-ignition stage in conventional engines. Recent laboratory failures have been assumed to be directly linked to operating foil bearings below their lift-off speed while following conventional startup procedures for the engines. In each instance, the continuous sliding contact between the foils and shaft was believed to thermally overload the bearing and cause the engines to fail. These failures highlight the need to characterize required acceleration rates and minimum operating speeds for these applications. In this report, startup experiments were conducted with a large, rotorcraft engine sized foil bearing under moderate load and acceleration rates to identify the proper start procedures needed to avoid bearing failure. The results showed that a bearing under a 39.4 kPa static load can withstand a modest acceleration rate of 500 rpm/s and excessive loitering below the bearing lift-off speed provided an adequate solid lubricant is present.

Probabilistic structural analysis of space propulsion system LOX post

NASA Technical Reports Server (NTRS)

Newell, J. F.; Rajagopal, K. R.; Ho, H. W.; Cunniff, J. M.

1990-01-01

The probabilistic structural analysis program NESSUS (Numerical Evaluation of Stochastic Structures Under Stress; Cruse et al., 1988) is applied to characterize the dynamic loading and response of the Space Shuttle main engine (SSME) LOX post. The design and operation of the SSME are reviewed; the LOX post structure is described; and particular attention is given to the generation of composite load spectra, the finite-element model of the LOX post, and the steps in the NESSUS structural analysis. The results are presented in extensive tables and graphs, and it is shown that NESSUS correctly predicts the structural effects of changes in the temperature loading. The probabilistic approach also facilitates (1) damage assessments for a given failure model (based on gas temperature, heat-shield gap, and material properties) and (2) correlation of the gas temperature with operational parameters such as engine thrust.

Design study of RL10 derivatives. Volume 3, part 1: Preliminary interface control document. [development of baseline engines for space tug vehicles

NASA Technical Reports Server (NTRS)

Adams, A.

1973-01-01

The Interface Control Document contains engine information necessary for installation of the baseline RL10 Derivative engines in the Space Tug vehicle. The ICD presents a description of the baseline engines and their operating characteristics, mass and load characteristics, and environmental criteria. The document defines the engine/vehicle mechanical, electrical, fluid and pneumatic interface requirements.

Influence of Compression Ratio on High Load Performance and Knock Behavior for Gasoline Port-Fuel Injection, Natural Gas Direct Injection and Blended Operation in a Spark Ignition Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pamminger, Michael; Sevik, James; Scarcelli, Riccardo

Natural Gas (NG) is an alternative fuel which has attracted a lot of attention recently, in particular in the US due to shale gas availability. The higher hydrogen-to-carbon (H/C) ratio, compared to gasoline, allows for decreasing carbon dioxide emissions throughout the entire engine map. Furthermore, the high knock resistance of NG allows increasing the efficiency at high engine loads compared to fuels with lower knock resistance. NG direct injection (DI) allows for fuel to be added after intake valve closing (IVC) resulting in an increase in power density compared to an injection before IVC. Steady-state engine tests were performed onmore » a single-cylinder research engine equipped with gasoline (E10) port-fuel injection (PFI) and NG DI to allow for in-cylinder blending of both fuels. Knock investigations were performed at two discrete compression ratios (CR), 10.5 and 12.5. Operating conditions span mid-load, wide-open-throttle and boosted conditions, depending on the knock response of the fuel blend. Blended operation was performed using E10 gasoline and NG. An additional gasoline type fuel (E85) with higher knock resistance than E10 was used as a high-octane reference fuel, since the octane rating of E10-NG fuel blends is unknown. Spark timing was varied at different loads under stoichiometric conditions in order to study the knock response as well as the effects on performance and efficiency. As anticipated, results suggest that the knock resistance can be increased significantly by increasing the NG amount. Comparing the engine operation with the least knock resistant fuel, E10 PFI, and the fuel blend with the highest knock resistance, 75% NG DI, shows an increase in indicated mean effective pressure of about 9 bar at CR 12.5. The usage of reference fuels with known knock characteristics allowed an assessment of knock characteristic of intermediate E10-NG blend levels. Mathematical correlations were developed allowing characterizing the occurrence of knocking combustion by using the Livengood-Wu knock integral. For most of the fueling strategies and operating conditions, the mathematical correlations show good agreement when compared to experimental data.« less

System catalytic neutralization control of combustion engines waste gases in mining technologies

NASA Astrophysics Data System (ADS)

Korshunov, G. I.; Solnitsev, R. I.

2017-10-01

The paper presents the problems solution of the atmospheric air pollution with the exhaust gases of the internal combustion engines, used in mining technologies. Such engines are used in excavators, bulldozers, dump trucks, diesel locomotives in loading and unloading processes and during transportation of minerals. NOx, CO, CH emissions as the waste gases occur during engine operation, the concentration of which must be reduced to the standard limits. The various methods and means are used for the problem solution, one of which is neutralization based on platinum catalysts. A mathematical model of a controlled catalytic neutralization system is proposed. The simulation results confirm the increase in efficiency at start-up and low engine load and the increase in the catalyst lifetime.

Increasing the resource of high load compression springs

NASA Astrophysics Data System (ADS)

Zemlyanushnova, N. Y.; Zemlyanushnov, N. A.

2017-10-01

Valve springs of VAZ automobiles’ engines are manufactured by using a new method. The decrease of dispersion of operating load in experimental springs compared to serial ones has been proved. The springs have passed a stress cycling test. With the new method having been used, it has been proved that the resource of high load springs working at high loading speed with coils collision has increased up to 60%.

Load cell verification of the uprated high pressure oxygen turbopump for the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Beatty, R. F.; Hine, M. J.

1986-01-01

The high pressure turbomachinery of the Space Shuttle Main Engine has the highest power-to-weight ratio of any operational machine known. Subsynchronous rotor whirl of the high pressure oxygen turbopump occurred in development testing at full-power level (109 percent thrust). The means by which the turbopump was successfully uprated is presented herein. The subsynchronous motion was determined to be driven by impeller destabilizing forces in combination with low net damping and bearing degradation. The degradation resulted from ball wear due primarily to an excessive loading condition of operating too near the lightly damped rotor second critical speed while under a large static load and, secondarily, from reverse bearing loading or loss of internal clearance and coolant during simulated flight conditions. The rotor response was reduced by stiffening the shaft and supports, optimizing the stiffness and damping of annular seals, and increasing the bearing deadband. The uprated oxygen turbopump configuration was verified by converting the pump and bearing support into a load cell for the purpose of systematically quantifying the load reduction benefits relative to baseline turbopumps. The damped second critical speed margin and the load sharing have been substantially improved which has resulted in reduced bearing loads for improved service life of the machine at full-power level.

Research and Development for Robotic Transportable Waste to Energy System (TWES)

DTIC Science & Technology

2012-01-01

Engineers, April 2003. NFESC UG-2039-ENV, Qualified Recycling Program (QRP) Guide; July 2000 (NOTAL) Paisley, M.A., Anson, D., “ Biomass Gasification ...Full Load Biomass Simulation .............................19 Figure 9. Spreadsheet-Based Heat and Mass Balance—Diesel Operation at 5:00 p.m...diesel fuel. Based on simulation of full-load biomass operation, the diesel-fueled test was expected to demonstrate a 75% net fuel-to-steam efficiency

An evaluation of retrofit engineering control interventions to reduce perchloroethylene exposures in commercial dry-cleaning shops.

PubMed

Earnest, G Scott; Ewers, Lynda M; Ruder, Avima M; Petersen, Martin R; Kovein, Ronald J

2002-02-01

Real-time monitoring was used to evaluate the ability of engineering control devices retrofitted on two existing dry-cleaning machines to reduce worker exposures to perchloroethylene. In one dry-cleaning shop, a refrigerated condenser was installed on a machine that had a water-cooled condenser to reduce the air temperature, improve vapor recovery, and lower exposures. In a second shop, a carbon adsorber was retrofitted on a machine to adsorb residual perchloroethylene not collected by the existing refrigerated condenser to improve vapor recovery and reduce exposures. Both controls were successful at reducing the perchloroethylene exposures of the dry-cleaning machine operator. Real-time monitoring was performed to evaluate how the engineering controls affected exposures during loading and unloading the dry-cleaning machine, a task generally considered to account for the highest exposures. The real-time monitoring showed that dramatic reductions occurred in exposures during loading and unloading of the dry-cleaning machine due to the engineering controls. Peak operator exposures during loading and unloading were reduced by 60 percent in the shop that had a refrigerated condenser installed on the dry-cleaning machine and 92 percent in the shop that had a carbon adsorber installed. Although loading and unloading exposures were dramatically reduced, drops in full-shift time-weighted average (TWA) exposures were less dramatic. TWA exposures to perchloroethylene, as measured by conventional air sampling, showed smaller reductions in operator exposures of 28 percent or less. Differences between exposure results from real-time and conventional air sampling very likely resulted from other uncontrolled sources of exposure, differences in shop general ventilation before and after the control was installed, relatively small sample sizes, and experimental variability inherent in field research. Although there were some difficulties and complications with installation and maintenance of the engineering controls, this study showed that retrofitting engineering controls may be a feasible option for some dry-cleaning shop owners to reduce worker exposures to perchloroethylene. By installing retrofit controls, a dry-cleaning facility can reduce exposures, in some cases dramatically, and bring operators into compliance with the Occupational Safety and Health Administration (OSHA) peak exposure limit of 300 ppm. Retrofit engineering controls are also likely to enable many dry-cleaning workers to lower their overall personal TWA exposures to perchloroethylene.

Thermodynamic feature of a Brownian heat engine operating between two heat baths.

PubMed

Asfaw, Mesfin

2014-01-01

A generalized theory of nonequilibrium thermodynamics for a Brownian motor operating between two different heat baths is presented. Via a simple paradigmatic model, we not only explore the thermodynamic feature of the engine in the regime of the nonequilibrium steady state but also study the short time behavior of the system for either the isothermal case with load or, in general, the nonisothermal case with or without load. Many elegant thermodynamic theories can be checked via the present model. Furthermore the dependence of the velocity, the efficiency, and the performance of the refrigerator on time t is examined. Our study reveals a current reversal due to time t. In the early system relaxation period, the model works neither as a heat engine nor as a refrigerator and only after a certain period of time does the model start functioning as a heat engine or as a refrigerator. The performance of the engine also improves with time and at steady state the engine manifests a higher efficiency or performance as a refrigerator. Furthermore the effect of energy exchange via the kinetic energy on the performance of the heat engine is explored.

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

DOEpatents

Dec, John E [Livermore, CA; Sjoberg, Carl-Magnus G [Livermore, CA

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.

Structural dynamics verification facility study

NASA Technical Reports Server (NTRS)

Kiraly, L. J.; Hirchbein, M. S.; Mcaleese, J. M.; Fleming, D. P.

1981-01-01

The need for a structural dynamics verification facility to support structures programs was studied. Most of the industry operated facilities are used for highly focused research, component development, and problem solving, and are not used for the generic understanding of the coupled dynamic response of major engine subsystems. Capabilities for the proposed facility include: the ability to both excite and measure coupled structural dynamic response of elastic blades on elastic shafting, the mechanical simulation of various dynamical loadings representative of those seen in operating engines, and the measurement of engine dynamic deflections and interface forces caused by alternative engine mounting configurations and compliances.

Efficiency measurement and uncertainty discussion of an electric engine powered by a ``self-breathing'' and ``self-humidified'' proton exchange membrane fuel cell

NASA Astrophysics Data System (ADS)

Schiavetti, Pierluigi; Del Prete, Zaccaria

2007-08-01

The efficiency of an automotive engine based on a "self-breathing" and "self-humidified" proton exchange membrane fuel cell stack (PEM FC) connected to a dc brushless electrical motor was measured under variable power load conditions. Experiments have been carried out on a small scale 150W engine model. After determining the fuel cell static polarization curve and the time response to power steps, the system was driven to copy on the test bench a "standard urban load cycle" and its instantaneous efficiencies were measured at an acquisition rate of 5Hz. The integral system efficiency over the entire urban load cycle, comprising the losses of the unavoidable auxiliary components of the engine, was then calculated. The fuel cell stack was operated mainly in "partial" dead-end mode, with a periodic anode flow channel purging, and one test was carried out in "pure" dead-end mode, with no anode channel purging. An uncertainty analysis of the efficiencies was carried out, taking into account either type A and type B evaluation methods, strengthening the discussion about the outcomes obtained for a system based on this novel simplified FC type. For our small scale engine we measured over the standard urban cycle, on the basis of the H2 high heating value (HHV), a tank-to-wheel integral efficiency of (18.2±0.8)%, when the fuel cell was operated with periodic flow channel purging, and of (21.5±1.3)% in complete dead-end operation mode.

Efficiency measurement and uncertainty discussion of an electric engine powered by a "self-breathing" and "self-humidified" proton exchange membrane fuel cell.

PubMed

Schiavetti, Pierluigi; Del Prete, Zaccaria

2007-08-01

The efficiency of an automotive engine based on a "self-breathing" and "self-humidified" proton exchange membrane fuel cell stack (PEM FC) connected to a dc brushless electrical motor was measured under variable power load conditions. Experiments have been carried out on a small scale 150 W engine model. After determining the fuel cell static polarization curve and the time response to power steps, the system was driven to copy on the test bench a "standard urban load cycle" and its instantaneous efficiencies were measured at an acquisition rate of 5 Hz. The integral system efficiency over the entire urban load cycle, comprising the losses of the unavoidable auxiliary components of the engine, was then calculated. The fuel cell stack was operated mainly in "partial" dead-end mode, with a periodic anode flow channel purging, and one test was carried out in "pure" dead-end mode, with no anode channel purging. An uncertainty analysis of the efficiencies was carried out, taking into account either type A and type B evaluation methods, strengthening the discussion about the outcomes obtained for a system based on this novel simplified FC type. For our small scale engine we measured over the standard urban cycle, on the basis of the H(2) high heating value (HHV), a tank-to-wheel integral efficiency of (18.2+/-0.8)%, when the fuel cell was operated with periodic flow channel purging, and of (21.5+/-1.3)% in complete dead-end operation mode.

Fuel composition and secondary organic aerosol formation: gas-turbine exhaust and alternative aviation fuels.

PubMed

Miracolo, Marissa A; Drozd, Greg T; Jathar, Shantanu H; Presto, Albert A; Lipsky, Eric M; Corporan, Edwin; Robinson, Allen L

2012-08-07

A series of smog chamber experiments were performed to investigate the effects of fuel composition on secondary particulate matter (PM) formation from dilute exhaust from a T63 gas-turbine engine. Tests were performed at idle and cruise loads with the engine fueled on conventional military jet fuel (JP-8), Fischer-Tropsch synthetic jet fuel (FT), and a 50/50 blend of the two fuels. Emissions were sampled into a portable smog chamber and exposed to sunlight or artificial UV light to initiate photo-oxidation. Similar to previous studies, neat FT fuel and a 50/50 FT/JP-8 blend reduced the primary particulate matter emissions compared to neat JP-8. After only one hour of photo-oxidation at typical atmospheric OH levels, the secondary PM production in dilute exhaust exceeded primary PM emissions, except when operating the engine at high load on FT fuel. Therefore, accounting for secondary PM production should be considered when assessing the contribution of gas-turbine engine emissions to ambient PM levels. FT fuel substantially reduced secondary PM formation in dilute exhaust compared to neat JP-8 at both idle and cruise loads. At idle load, the secondary PM formation was reduced by a factor of 20 with the use of neat FT fuel, and a factor of 2 with the use of the blend fuel. At cruise load, the use of FT fuel resulted in no measured formation of secondary PM. In every experiment, the secondary PM was dominated by organics with minor contributions from sulfate when the engine was operated on JP-8 fuel. At both loads, FT fuel produces less secondary organic aerosol than JP-8 because of differences in the composition of the fuels and the resultant emissions. This work indicates that fuel reformulation may be a viable strategy to reduce the contribution of emissions from combustion systems to secondary organic aerosol production and ultimately ambient PM levels.

40 CFR 90.404 - Test procedure overview.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test... operating conditions to be conducted on an engine dynamometer or equivalent load and speed measurement... to determine the brake-specific emissions of non-methane hydrocarbons. The test consists of three...

Performance and operational improvements made to the Waukesha AT27-GL engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinbold, E.O.

1996-12-31

This paper presents the results of combustion and engine performance studies performed on the AT27GL lean burn engine. One study was to evaluate the effect of the pre-combustion chamber cup geometry on engine performance under several operating conditions including: Air-Fuel Ratio (AFR), ignition timing, and engine load. The study examined several combustion parameters; including IMEP, coefficient of variation of IMEP, heat release rates, and maximum combustion pressures. The study also examined engine thermal efficiency, and brake specific emissions of Oxides of Nitrogen, Carbon Monoxide, and Total Hydrocarbons (gaseous). Studies were also performed on different spark plug designs, comparing firing voltages,more » and electrode temperatures while operating under conditions of varying AFR, and ignition timing. In addition an Air-Fuel-Ratio controller was recently tested and released on the engine. The controller was tested under conditions of varying fuel quality, along with a detonation control system.« less

Vehicle Integrated Photovoltaics for Compression Ignition Vehicles: An Experimental Investigation of Solar Alkaline Water Electrolysis for Improving Diesel Combustion and a Solar Charging System for Reducing Auxiliary Engine Loads

NASA Astrophysics Data System (ADS)

Negroni, Garry Inocentes

Vehicle-integrated photovoltaic electricity can be applied towards aspiration of hydrogen-oxygen-steam gas produced through alkaline electrolysis and reductions in auxiliary alternator load for reducing hydrocarbon emissions in low nitrogen oxide indirect-injection compression-ignition engines. Aspiration of 0.516 ± 0.007 liters-per-minute of gas produced through alkaline electrolysis of potassium-hydroxide 2wt.% improves full-load performance; however, part-load performance decreases due to auto-ignition of aspirated gas prior to top-dead center. Alternator load reductions offer improved part-load and full-load performance with practical limitations resulting from accessory electrical loads. In an additive approach, solar electrolysis can electrochemically convert solar photovoltaic electricity into a gas comprised of stoichiometric hydrogen and oxygen gas. Aspiration of this hydrogen-oxygen gas enhances combustion properties decreasing emissions and increased combustion efficiency in light-duty diesel vehicles. The 316L stainless steel (SS) electrolyser plates are arranged with two anodes and three cathodes space with four bipolar plates delineating four stacks in parallel with five cells per stack. The electrolyser was tested using potassium hydroxide 2 wt.% and hydronium 3wt.% at measured voltage and current inputs. The flow rate output from the reservoir cell was measured in parallel with the V and I inputs producing a regression model correlating current input to flow rate. KOH 2 wt.% produced 0.005 LPM/W, while H9O44 3 wt.% produced less at 0.00126 LPM/W. In a subtractive approach, solar energy can be used to charge a larger energy storage device, as is with plug-in electric vehicles, in order to alleviate the engine of the mechanical load placed upon it by the vehicles electrical accessories through the alternator. Solar electrolysis can improve part-load emissions and full-load performance. The average solar-to-battery efficiency based on the OEM rated efficiency was 11.4%. The average voltage efficiency of the electrolyser during dynamometer testing was 69.16%, producing a solar-to-electrolysis efficiency of 7.88%. At varying engine speeds, HC emissions decreased an average of 54.4% at multiple engine speeds at part-load, while CO2 increased by 2.54% due to oxygen enrichment of intake air. However, the auto-ignition of a small amount of hydrogen (0.0035% of diesel fuel energy) had a negative impact on part-load power (-3.671%) and torque (-3.296%). Full-load sweep testing showed an increase in peak power (1.562%) and peak torque (2.608%). Solar electrolysis gas aspiration reduced soot opacity by 31.5%. The alternator-less part-load step tests show average HC and CO2 emissions decrease on average 25.05% and 1.14% respectively. The test also indicates an increase in average part-load power (1.57%) and torque (2.12%). Alternator-less operation can reduce soot opacity by 56.76%. Full-load testing of the vehicle with alternator unplugged indicates that alternator load upon an engine increase with engine ne speed even with no load and no pilot excitation. Alternator load elimination's performance and emissions improvements should be considered, however, practical limitations exist in winter-night, summer-midday scenarios and for longer duration of operation.

Effects of biodiesel, engine load and diesel particulate filter on nonvolatile particle number size distributions in heavy-duty diesel engine exhaust.

PubMed

Young, Li-Hao; Liou, Yi-Jyun; Cheng, Man-Ting; Lu, Jau-Huai; Yang, Hsi-Hsien; Tsai, Ying I; Wang, Lin-Chi; Chen, Chung-Bang; Lai, Jim-Shoung

2012-01-15

Diesel engine exhaust contains large numbers of submicrometer particles that degrade air quality and human health. This study examines the number emission characteristics of 10-1000 nm nonvolatile particles from a heavy-duty diesel engine, operating with various waste cooking oil biodiesel blends (B2, B10 and B20), engine loads (0%, 25%, 50% and 75%) and a diesel oxidation catalyst plus diesel particulate filter (DOC+DPF) under steady modes. For a given load, the total particle number concentrations (N(TOT)) decrease slightly, while the mode diameters show negligible changes with increasing biodiesel blends. For a given biodiesel blend, both the N(TOT) and mode diameters increase modestly with increasing load of above 25%. The N(TOT) at idle are highest and their size distributions are strongly affected by condensation and possible nucleation of semivolatile materials. Nonvolatile cores of diameters less than 16 nm are only observed at idle mode. The DOC+DPF shows remarkable filtration efficiency for both the core and soot particles, irrespective of the biodiesel blend and engine load under study. The N(TOT) post the DOC+DPF are comparable to typical ambient levels of ≈ 10(4)cm(-3). This implies that, without concurrent reductions of semivolatile materials, the formation of semivolatile nucleation mode particles post the after treatment is highly favored. Copyright © 2011 Elsevier B.V. All rights reserved.

29 CFR 1926.552 - Material hoists, personnel hoists, and elevators.

Code of Federal Regulations, 2011 CFR

2011-07-01

... engineer competent in the field. (2) Rated load capacities, recommended operating speeds, and special..., scrubbing, flattening, or peening, causing loss of more than one-third of the original diameter of the... station of the hoist. Such rules shall include signal system and allowable line speed for various loads...

29 CFR 1926.552 - Material hoists, personnel hoists, and elevators.

Code of Federal Regulations, 2014 CFR

2014-07-01

... engineer competent in the field. (2) Rated load capacities, recommended operating speeds, and special..., scrubbing, flattening, or peening, causing loss of more than one-third of the original diameter of the... station of the hoist. Such rules shall include signal system and allowable line speed for various loads...

29 CFR 1926.552 - Material hoists, personnel hoists, and elevators.

Code of Federal Regulations, 2013 CFR

2013-07-01

... engineer competent in the field. (2) Rated load capacities, recommended operating speeds, and special..., scrubbing, flattening, or peening, causing loss of more than one-third of the original diameter of the... station of the hoist. Such rules shall include signal system and allowable line speed for various loads...

29 CFR 1926.552 - Material hoists, personnel hoists, and elevators.

Code of Federal Regulations, 2012 CFR

2012-07-01

... engineer competent in the field. (2) Rated load capacities, recommended operating speeds, and special..., scrubbing, flattening, or peening, causing loss of more than one-third of the original diameter of the... station of the hoist. Such rules shall include signal system and allowable line speed for various loads...

29 CFR 1926.552 - Material hoists, personnel hoists, and elevators.

Code of Federal Regulations, 2010 CFR

2010-07-01

... engineer competent in the field. (2) Rated load capacities, recommended operating speeds, and special..., scrubbing, flattening, or peening, causing loss of more than one-third of the original diameter of the... station of the hoist. Such rules shall include signal system and allowable line speed for various loads...

Acoustic measurements for the combustion diagnosis of diesel engines fuelled with biodiesels

NASA Astrophysics Data System (ADS)

Zhen, Dong; Wang, Tie; Gu, Fengshou; Tesfa, Belachew; Ball, Andrew

2013-05-01

In this paper, an experimental investigation was carried out on the combustion process of a compression ignition (CI) engine running with biodiesel blends under steady state operating conditions. The effects of biodiesel on the combustion process and engine dynamics were analysed for non-intrusive combustion diagnosis based on a four-cylinder, four-stroke, direct injection and turbocharged diesel engine. The signals of vibration, acoustic and in-cylinder pressure were measured simultaneously to find their inter-connection for diagnostic feature extraction. It was found that the sound energy level increases with the increase of engine load and speed, and the sound characteristics are closely correlated with the variation of in-cylinder pressure and combustion process. The continuous wavelet transform (CWT) was employed to analyse the non-stationary nature of engine noise in a higher frequency range. Before the wavelet analysis, time synchronous average (TSA) was used to enhance the signal-to-noise ratio (SNR) of the acoustic signal by suppressing the components which are asynchronous. Based on the root mean square (RMS) values of CWT coefficients, the effects of biodiesel fractions and operating conditions (speed and load) on combustion process and engine dynamics were investigated. The result leads to the potential of airborne acoustic measurements and analysis for engine condition monitoring and fuel quality evaluation.

TOPSIS-based parametric optimization of compression ignition engine performance and emission behavior with bael oil blends for different EGR and charge inlet temperature.

PubMed

Muniappan, Krishnamoorthi; Rajalingam, Malayalamurthi

2018-05-02

The demand for higher fuel energy and lesser exhaust emissions of diesel engines can be achieved by fuel being used and engine operating parameters. In the present work, effects of engine speed (RPM), injection timing (IT), injection pressure (IP), and compression ratio (CR) on performance and emission characteristics of a compression ignition (CI) engine were investigated. The ternary test fuel of 65% diesel + 25% bael oil + 10% diethyl ether (DEE) was used in this work and test was conducted at different charge inlet temperature (CIT) and exhaust gas recirculation (EGR). All the experiments are conducted at the tradeoff engine load that is 75% engine load. When operating the diesel engine with 320 K CIT, brake thermal efficiency (BTE) is improved to 28.6%, and carbon monoxide (CO) and hydrocarbon (HC) emissions have been reduced to 0.025% and 12.5 ppm at 18 CR. The oxide of nitrogen (NOx) has been reduced to 240 ppm at 1500 rpm for 30% EGR mode. Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method is frequently used in multi-factor selection and gray correlation analysis method is used to study uncertain of the systems.

Comparison of two total energy systems for a diesel power generation plant. [deep space network

NASA Technical Reports Server (NTRS)

Chai, V. W.

1979-01-01

The capabilities and limitations, as well as the associated costs for two total energy systems for a diesel power generation plant are compared. Both systems utilize waste heat from engine cooling water and waste heat from exhaust gases. Pressurized water heat recovery system is simple in nature and requires no engine modifications, but operates at lower temperature ranges. On the other hand, a two-phase ebullient system operates the engine at constant temperature, provides higher temperature water or steam to the load, but is more expensive.

Experimental investigation of in-cylinder air flow to optimize number of helical guide vanes to enhance DI diesel engine performance using mamey sapote biodiesel

NASA Astrophysics Data System (ADS)

Kumar, A. Raj; Janardhana Raju, G.; Hemachandra Reddy, K.

2018-03-01

The current research work investigates the influence of helical guide vanes in to the intake runner of a D.I diesel engine operating by the high viscous Mamey Sapote biodiesel to enhance in-cylinder suction air flow features. Helical guide vanes of different number of vanes are produced from 3D printing and placed in the intake manifold to examine the air flow characteristics. Four different helical guide vane devices namely 3, 4, 5 and 6 vanes of the same dimensions are tested in a D.I diesel engine operating with Mamey Sapote biodiesel blend. As per the experimental results of engine performance and emission characteristics, it is found that 5 vanes helical guide vane swirl device exhibited in addition number of increased improvements such as the brake power and bake thermal efficiency by 2.4% and 8.63% respectively and the HC, NOx, Carbon monoxide and, Smoke densities are reduced by 15.62%, 4.23%, 14.27% and 9.6% at peak load operating conditions as collate with normal engine at the same load. Hence this investigation concluded that Helical Guide Vane Devices successfully enhanced the in-cylinder air flow to improve better addition of Mamey Sapote biodiesel with air leading in better performance of the engine than without vanes.

Testing and performance characteristics of a 1-kW free piston Stirling engine

NASA Technical Reports Server (NTRS)

Schreiber, J.

1983-01-01

A 1 kW single cylinder free piston Stirling engine, configured as a research engine, was tested with helium working gas. The engine features a posted displacer and dashpot load. The test results show the engine power output and efficiency to be lower than those observed during acceptance tests by the manufacturer. Engine tests results are presented for operation at the two heater head temperatures and with two regenerator porosities, along with flow test results for the heat exchangers.

Field Measurements of Particulate Matter Emissions, Carbon Monoxide, and Exhaust Opacity from Heavy-Duty Diesel Vehicles.

PubMed

Clark, Nigel N; Jarrett, Ronald P; Atkinson, Christopher M

1999-09-01

Diesel particulate matter (PM) is a significant contributor to ambient air PM 10 and PM 2.5 particulate levels. In addition, recent literature argues that submicron diesel PM is a pulmonary health hazard. There is difficulty in attributing PM emissions to specific operating modes of a diesel engine, although it is acknowledged that PM production rises dramatically with load and that high PM emissions occur during rapid load increases on turbocharged engines. Snap-acceleration tests generally identify PM associated with rapid transient operating conditions, but not with high load. To quantify the origin of PM during transient engine operation, continuous opacity measurements have been made using a Wager 650CP full flow exhaust opacity meter. Opacity measurements were taken while the vehicles were operated over transient driving cycles on a chassis dynamometer using the West Virginia University (WVU) Transportable Heavy Duty Vehicle Emissions Testing Laboratories. Data were gathered from Detroit Diesel, Cummins, Caterpillar, and Navistar heavy-duty (HD) diesel engines. Driving cycles used were the Central Business District (CBD) cycle, the WVU 5-Peak Truck cycle, the WVU 5-Mile route, and the New York City Bus (NYCB) cycle. Continuous opacity measurements, integrated over the entire driving cycle, were compared to total integrated PM mass. In addition, the truck was subjected to repeat snap-acceleration tests, and PM was collected for a composite of these snap-acceleration tests. Additional data were obtained from a fleet of 1996 New Flyer buses in Flint, MI, equipped with electronically controlled Detroit Diesel Series 50 engines. Again, continuous opacity, regulated gaseous emissions, and PM were measured. The relationship between continuous carbon monoxide (CO) emissions and continuous opacity was noted. In identifying the level of PM emissions in transient diesel engine operation, it is suggested that CO emissions may prove to be a useful indicator and may be used to apportion total PM on a continuous basis over a transient cycle. The projected continuous PM data will prove valuable in future mobile source inventory prediction.

76 FR 61033 - Airworthiness Directives; The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-03

... an inspection of the aft engine mount to determine if the center link assembly is correctly installed... reports indicating that operators found that the center link assembly for the aft engine mount was... prevent increased structural loads on the aft engine mount, which could result in failure of the aft...

Military Hybrid Vehicle Survey

DTIC Science & Technology

2011-08-03

III Composite 4.3% Integrated starter generator for engine shut down, regenerative braking and avoidance of inefficient engine operation [28]. FMTV...eliminating the inefficiencies associated with idling, vehicle braking and low engine speed part load efficiency, many improvements can be realized...literature. They can be divided into the following two categories : (1) Time dependent speed profiles, shown in Figure 4, usually defined by the federal

Current State of Military Hybrid Vehicle Development

DTIC Science & Technology

2011-08-31

Integrated starter generator for engine shut down, regenerative braking and avoidance of inefficient engine operation [28]. FMTV VI Composite 6-9% Fuel...and eliminating the inefficiencies associated with idling, vehicle braking and low engine speed part load efficiency, many improvements could be...different drive cycles were being used to evaluate vehicle performance. These cycles can be divided into the following two categories : (1) Time

Effect of compression ratio, nozzle opening pressure, engine load, and butanol addition on nanoparticle emissions from a non-road diesel engine.

PubMed

Maurya, Rakesh Kumar; Saxena, Mohit Raj; Rai, Piyush; Bhardwaj, Aashish

2018-05-01

Currently, diesel engines are more preferred over gasoline engines due to their higher torque output and fuel economy. However, diesel engines confront major challenge of meeting the future stringent emission norms (especially soot particle emissions) while maintaining the same fuel economy. In this study, nanosize range soot particle emission characteristics of a stationary (non-road) diesel engine have been experimentally investigated. Experiments are conducted at a constant speed of 1500 rpm for three compression ratios and nozzle opening pressures at different engine loads. In-cylinder pressure history for 2000 consecutive engine cycles is recorded and averaged data is used for analysis of combustion characteristics. An electrical mobility-based fast particle sizer is used for analyzing particle size and mass distributions of engine exhaust particles at different test conditions. Soot particle distribution from 5 to 1000 nm was recorded. Results show that total particle concentration decreases with an increase in engine operating loads. Moreover, the addition of butanol in the diesel fuel leads to the reduction in soot particle concentration. Regression analysis was also conducted to derive a correlation between combustion parameters and particle number emissions for different compression ratios. Regression analysis shows a strong correlation between cylinder pressure-based combustion parameters and particle number emission.

Identification and quantification analysis of nonlinear dynamics properties of combustion instability in a diesel engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Li-Ping, E-mail: yangliping302@hrbeu.edu.cn; Ding, Shun-Liang; Song, En-Zhe

The cycling combustion instabilities in a diesel engine have been analyzed based on chaos theory. The objective was to investigate the dynamical characteristics of combustion in diesel engine. In this study, experiments were performed under the entire operating range of a diesel engine (the engine speed was changed from 600 to 1400 rpm and the engine load rate was from 0% to 100%), and acquired real-time series of in-cylinder combustion pressure using a piezoelectric transducer installed on the cylinder head. Several methods were applied to identify and quantitatively analyze the combustion process complexity in the diesel engine including delay-coordinate embedding, recurrencemore » plot (RP), Recurrence Quantification Analysis, correlation dimension (CD), and the largest Lyapunov exponent (LLE) estimation. The results show that the combustion process exhibits some determinism. If LLE is positive, then the combustion system has a fractal dimension and CD is no more than 1.6 and within the diesel engine operating range. We have concluded that the combustion system of diesel engine is a low-dimensional chaotic system and the maximum values of CD and LLE occur at the lowest engine speed and load. This means that combustion system is more complex and sensitive to initial conditions and that poor combustion quality leads to the decrease of fuel economy and the increase of exhaust emissions.« less

Identification and quantification analysis of nonlinear dynamics properties of combustion instability in a diesel engine.

PubMed

Yang, Li-Ping; Ding, Shun-Liang; Litak, Grzegorz; Song, En-Zhe; Ma, Xiu-Zhen

2015-01-01

The cycling combustion instabilities in a diesel engine have been analyzed based on chaos theory. The objective was to investigate the dynamical characteristics of combustion in diesel engine. In this study, experiments were performed under the entire operating range of a diesel engine (the engine speed was changed from 600 to 1400 rpm and the engine load rate was from 0% to 100%), and acquired real-time series of in-cylinder combustion pressure using a piezoelectric transducer installed on the cylinder head. Several methods were applied to identify and quantitatively analyze the combustion process complexity in the diesel engine including delay-coordinate embedding, recurrence plot (RP), Recurrence Quantification Analysis, correlation dimension (CD), and the largest Lyapunov exponent (LLE) estimation. The results show that the combustion process exhibits some determinism. If LLE is positive, then the combustion system has a fractal dimension and CD is no more than 1.6 and within the diesel engine operating range. We have concluded that the combustion system of diesel engine is a low-dimensional chaotic system and the maximum values of CD and LLE occur at the lowest engine speed and load. This means that combustion system is more complex and sensitive to initial conditions and that poor combustion quality leads to the decrease of fuel economy and the increase of exhaust emissions.

Experimental investigation on the performance, gaseous and particulate emissions of a methanol fumigated diesel engine.

PubMed

Cheng, C H; Cheung, C S; Chan, T L; Lee, S C; Yao, C D

2008-01-15

Experiments were conducted on a 4-cylinder direct-injection diesel engine with fumigation methanol injected into the air intake of each cylinder. The fumigation methanol was injected to top up 10%, 20% and 30% of the power output under different engine operating conditions. The effects of fumigation methanol on engine performance, gaseous emissions and particulate emission were investigated. The experimental results show that there is a decrease in the brake thermal efficiency when fumigation methanol is applied, except at the highest load of 0.67 MPa. At low loads, the brake thermal efficiency decreases with increase in fumigation methanol; but at high loads, it increases with increase in fumigation methanol. The fumigation method results in a significant increase in hydrocarbon (HC), carbon monoxide (CO), and nitrogen dioxide (NO(2)) emissions. The concentration of nitrogen oxides (NOx) is significantly reduced except at close to full load condition. There is also a reduction in the smoke opacity and the particulate matter (PM) mass concentration. For the submicron particles, the total number of particles decreases at low and medium loads but increases at high loads. In all cases, there is a shift of the particles towards smaller geometrical mean diameter, especially at high loads. The increase in nano-sized particles and the increase in NO(2) emission could have serious impact on human health.

Application of an EGR system in a direct injection diesel engine to reduce NOx emissions

NASA Astrophysics Data System (ADS)

De Serio, D.; De Oliveira, A.; Sodré, J. R.

2016-09-01

This work presents the application of an exhaust gas recirculation (EGR) system in a direct injection diesel engine operating with diesel oil containing 7% biodiesel (B7). EGR rates of up to 10% were applied with the primary aim to reduce oxides of nitrogen (NOx) emissions. The experiments were conducted in a 44 kW diesel power generator to evaluate engine performance and emissions for different load settings. The use of EGR caused a peak pressure reduction during the combustion process and a decrease in thermal efficiency, mainly at high engine loads. A reduction of NOx emissions of up to 26% was achieved, though penalizing carbon monoxide (CO) and total hydrocarbons (THC) emissions.

Design and development of the Waukesha Custom Engine Control Air/Fuel Module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moss, D.W.

1996-12-31

The Waukesha Custom Engine Control Air/Fuel Module (AFM) is designed to control the air-fuel ratio for all Waukesha carbureted, gaseous fueled, industrial engine. The AFM is programmed with a personal computer to run in one of four control modes: catalyst, best power, best economy, or lean-burn. One system can control naturally aspirated, turbocharged, in-line or vee engines. The basic system consists of an oxygen sensing system, intake manifold pressure transducer, electronic control module, actuator and exhaust thermocouple. The system permits correct operation of Waukesha engines in spite of changes in fuel pressure or temperature, engine load or speed, and fuelmore » composition. The system utilizes closed loop control and is centered about oxygen sensing technology. An innovative approach to applying oxygen sensors to industrial engines provides very good performance, greatly prolongs sensor life, and maintains sensor accuracy. Design considerations and operating results are given for application of the system to stationary, industrial engines operating on fuel gases of greatly varying composition.« less

Advanced Earth-to-orbit propulsion technology program overview: Impact of civil space technology initiative

NASA Technical Reports Server (NTRS)

Stephenson, Frank W., Jr.

1988-01-01

The NASA Earth-to-Orbit (ETO) Propulsion Technology Program is dedicated to advancing rocket engine technologies for the development of fully reusable engine systems that will enable space transportation systems to achieve low cost, routine access to space. The program addresses technology advancements in the areas of engine life extension/prediction, performance enhancements, reduced ground operations costs, and in-flight fault tolerant engine operations. The primary objective is to acquire increased knowledge and understanding of rocket engine chemical and physical processes in order to evolve more realistic analytical simulations of engine internal environments, to derive more accurate predictions of steady and unsteady loads, and using improved structural analyses, to more accurately predict component life and performance, and finally to identify and verify more durable advanced design concepts. In addition, efforts were focused on engine diagnostic needs and advances that would allow integrated health monitoring systems to be developed for enhanced maintainability, automated servicing, inspection, and checkout, and ultimately, in-flight fault tolerant engine operations.

Passive SCR for lean gasoline NO X control: Engine-based strategies to minimize fuel penalty associated with catalytic NH 3 generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prikhodko, Vitaly Y.; Parks, James E.; Pihl, Josh A.

Lean gasoline engines offer greater fuel economy than common stoichiometric gasoline engines. However, excess oxygen prevents the use of the current three-way catalyst (TWC) to control nitrogen oxide (NO X) emissions in lean exhaust. A passive SCR concept, introduced by General Motors Global R&D, makes use of a TWC that is already onboard to generate NH 3 under slightly rich conditions, which is stored on the downstream SCR. The stored NH 3 is then used to reduce NO X emissions when the engine switches to lean operation. In this work, the effect of engine parameters, such as air-fuel equivalence ratiomore » and spark timing, on NH 3 generation over a commercial Pd-only TWC with no dedicated oxygen storage component was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine. NO X reduction, NH 3 formation, and reductant utilization processes were evaluated, and fuel efficiency was assessed and compared to the stoichiometric engine operation case. We found air-fuel equivalence ratio to be one of the most important parameters in controlling the NH 3 production; however, the rich operation necessary for NH 3 production results in a fuel consumption penalty. The fuel penalty can be minimized by adjusting spark timing to increase rich-phase engine out NO X emissions and, thereby, NH 3 levels. Additionally, higher engine out NO X during engine load increase to simulate acceleration resulted in additional fuel savings. Ultimately, a 10% fuel consumption benefit was achieved with the passive SCR approach by optimizing rich air-fuel equivalence ratio and spark timing while also utilizing acceleration load conditions.« less

Passive SCR for lean gasoline NO X control: Engine-based strategies to minimize fuel penalty associated with catalytic NH 3 generation

DOE PAGES

Prikhodko, Vitaly Y.; Parks, James E.; Pihl, Josh A.; ...

2016-02-18

Lean gasoline engines offer greater fuel economy than common stoichiometric gasoline engines. However, excess oxygen prevents the use of the current three-way catalyst (TWC) to control nitrogen oxide (NO X) emissions in lean exhaust. A passive SCR concept, introduced by General Motors Global R&D, makes use of a TWC that is already onboard to generate NH 3 under slightly rich conditions, which is stored on the downstream SCR. The stored NH 3 is then used to reduce NO X emissions when the engine switches to lean operation. In this work, the effect of engine parameters, such as air-fuel equivalence ratiomore » and spark timing, on NH 3 generation over a commercial Pd-only TWC with no dedicated oxygen storage component was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine. NO X reduction, NH 3 formation, and reductant utilization processes were evaluated, and fuel efficiency was assessed and compared to the stoichiometric engine operation case. We found air-fuel equivalence ratio to be one of the most important parameters in controlling the NH 3 production; however, the rich operation necessary for NH 3 production results in a fuel consumption penalty. The fuel penalty can be minimized by adjusting spark timing to increase rich-phase engine out NO X emissions and, thereby, NH 3 levels. Additionally, higher engine out NO X during engine load increase to simulate acceleration resulted in additional fuel savings. Ultimately, a 10% fuel consumption benefit was achieved with the passive SCR approach by optimizing rich air-fuel equivalence ratio and spark timing while also utilizing acceleration load conditions.« less

40 CFR 1065.110 - Work inputs and outputs, accessory work, and operator demand.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-current and water-brake dynamometers for any testing that does not involve engine motoring, which is... resistor load bank to simulate electrical loads. (3) Pump, compressor, and turbine work. Use pumps, compressors, and turbines that are of the type and capacity installed in use. Use working fluids that are of...

40 CFR 1065.110 - Work inputs and outputs, accessory work, and operator demand.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-current and water-brake dynamometers for any testing that does not involve engine motoring, which is... resistor load bank to simulate electrical loads. (3) Pump, compressor, and turbine work. Use pumps, compressors, and turbines that are of the type and capacity installed in use. Use working fluids that are of...

40 CFR 1065.110 - Work inputs and outputs, accessory work, and operator demand.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-current and water-brake dynamometers for any testing that does not involve engine motoring, which is... resistor load bank to simulate electrical loads. (3) Pump, compressor, and turbine work. Use pumps, compressors, and turbines that are of the type and capacity installed in use. Use working fluids that are of...

40 CFR 1065.110 - Work inputs and outputs, accessory work, and operator demand.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-current and water-brake dynamometers for any testing that does not involve engine motoring, which is... resistor load bank to simulate electrical loads. (3) Pump, compressor, and turbine work. Use pumps, compressors, and turbines that are of the type and capacity installed in use. Use working fluids that are of...

40 CFR 1065.110 - Work inputs and outputs, accessory work, and operator demand.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-current and water-brake dynamometers for any testing that does not involve engine motoring, which is... resistor load bank to simulate electrical loads. (3) Pump, compressor, and turbine work. Use pumps, compressors, and turbines that are of the type and capacity installed in use. Use working fluids that are of...

Nonlinear engine model for idle speed control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Livshiz, M.; Sanvido, D.J.; Stiles, S.D.

1994-12-31

This paper describes a nonlinear model of an engine used for the design of idle speed control and prediction in a broad range of idle speeds and operational conditions. Idle speed control systems make use of both spark advance and the idle air actuator to control engine speed for improved response relative to variations in the target idle speed due to load disturbances. The control system at idle can be presented by a multiple input multiple output (MIMO) nonlinear model. Information of nonlinearities helps to improve performance of the system over the whole range of engine speeds. A proposed simplemore » nonlinear model of the engine at idle was applied for design of optimal controllers and predictors for improved steady state, load rejection and transition from and to idle. This paper describes vehicle results of engine speed prediction based on the described model.« less

Gaseous and Particulate Emissions from Diesel Engines at Idle and under Load: Comparison of Biodiesel Blend and Ultralow Sulfur Diesel Fuels

PubMed Central

Chin, Jo-Yu; Batterman, Stuart A.; Northrop, William F.; Bohac, Stanislav V.; Assanis, Dennis N.

2015-01-01

Diesel exhaust emissions have been reported for a number of engine operating strategies, after-treatment technologies, and fuels. However, information is limited regarding emissions of many pollutants during idling and when biodiesel fuels are used. This study investigates regulated and unregulated emissions from both light-duty passenger car (1.7 L) and medium-duty (6.4 L) diesel engines at idle and load and compares a biodiesel blend (B20) to conventional ultralow sulfur diesel (ULSD) fuel. Exhaust aftertreatment devices included a diesel oxidation catalyst (DOC) and a diesel particle filter (DPF). For the 1.7 L engine under load without a DOC, B20 reduced brake-specific emissions of particulate matter (PM), elemental carbon (EC), nonmethane hydrocarbons (NMHCs), and most volatile organic compounds (VOCs) compared to ULSD; however, formaldehyde brake-specific emissions increased. With a DOC and high load, B20 increased brake-specific emissions of NMHC, nitrogen oxides (NOx), formaldehyde, naphthalene, and several other VOCs. For the 6.4 L engine under load, B20 reduced brake-specific emissions of PM2.5, EC, formaldehyde, and most VOCs; however, NOx brake-specific emissions increased. When idling, the effects of fuel type were different: B20 increased NMHC, PM2.5, EC, formaldehyde, benzene, and other VOC emission rates from both engines, and changes were sometimes large, e.g., PM2.5 increased by 60% for the 6.4 L/2004 calibration engine, and benzene by 40% for the 1.7 L engine with the DOC, possibly reflecting incomplete combustion and unburned fuel. Diesel exhaust emissions depended on the fuel type and engine load (idle versus loaded). The higher emissions found when using B20 are especially important given the recent attention to exposures from idling vehicles and the health significance of PM2.5. The emission profiles demonstrate the effects of fuel type, engine calibration, and emission control system, and they can be used as source profiles for apportionment, inventory, and exposure purposes. PMID:25722535

Balancing low cost with reliable operation in the rotordynamic design of the ALS Liquid Hydrogen Fuel Turbopump

NASA Technical Reports Server (NTRS)

Greenhill, L. M.

1990-01-01

The Air Force/NASA Advanced Launch System (ALS) Liquid Hydrogen Fuel Turbopump (FTP) has primary design goals of low cost and high reliability, with performance and weight having less importance. This approach is atypical compared with other rocket engine turbopump design efforts, such as on the Space Shuttle Main Engine (SSME), which emphasized high performance and low weight. Similar to the SSME turbopumps, the ALS FTP operates supercritically, which implies that stability and bearing loads strongly influence the design. In addition, the use of low cost/high reliability features in the ALS FTP such as hydrostatic bearings, relaxed seal clearances, and unshrouded turbine blades also have a negative influence on rotordynamics. This paper discusses the analysis conducted to achieve a balance between low cost and acceptable rotordynamic behavior, to ensure that the ALS FTP will operate reliably without subsynchronous instabilities or excessive bearing loads.

Wind Turbine Modeling Overview for Control Engineers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moriarty, P. J.; Butterfield, S. B.

2009-01-01

Accurate modeling of wind turbine systems is of paramount importance for controls engineers seeking to reduce loads and optimize energy capture of operating turbines in the field. When designing control systems, engineers often employ a series of models developed in the different disciplines of wind energy. The limitations and coupling of each of these models is explained to highlight how these models might influence control system design.

Shop test of the 501F; A 150 MW combustion turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Entenmann, D.T.; North, W.E.; Fukue, I.

1991-10-01

The 501F is a 150 MW-class 60 Hz engine jointly developed by Westinghouse Electric Corporation and Mitsubishi Heavy Industries, Ltd. This paper describes the full-load shop test program for the prototype engine, as carried out in Takasago, Japan. The shop test included a full range of operating conditions, from startup through full load at the 1260{degrees} C (2300{degrees} F) design turbine inlet temperature. The engine was prepared with more than 1500 instrumentation points to monitor flow path characteristics, metal temperatures, displacements, pressures, cooling circuit characteristics, strains, sound pressure levels, and exhaust emissions. The results of this shop test indicate themore » new 501F engine design and development effort to be highly successful. The engine exceeds power and overall efficiency expectations, thus verifying the new concepts and design improvements.« less

Fatigue Lifespan of Engine Box Influenced by Fan Blade Out

NASA Astrophysics Data System (ADS)

Qiu, Ju; Shi, Jingwei; Su, Huaizhong; Zhang, Jinling; Feng, Juan; Shi, Qian; Tian, Xiaoyu

2017-11-01

This provides precious experience and reliable reference data for future design. This paper introduces the analysis process of Fan-blade-out, and considers the effect of windmill load on the fatigue lifespan of the case. According to Extended Operations (ETOPS) in the airworthiness regulations, the fatigue crack of it is analyzed by the unbalanced rotor load, during FBO. Compared with the lifespan in normal work of the engine, this research provides valuable design experience and reliable reference data for the case design in the near future.

Rotary Stirling-Cycle Engine And Generator

NASA Technical Reports Server (NTRS)

Chandler, Joseph A.

1990-01-01

Proposed electric-power generator comprises three motor generators coordinated by microprocessor and driven by rotary Stirling-cycle heat engine. Combination offers thermodynamic efficiency of Stirling cycle, relatively low vibration, and automatic adjustment of operating parameters to suit changing load on generator. Rotary Stirling cycle engine converts heat to power via compression and expansion of working gas between three pairs of rotary pistons on three concentric shafts in phased motion. Three motor/generators each connected to one of concentric shafts, can alternately move and be moved by pistons. Microprocessor coordinates their operation, including switching between motor and generator modes at appropriate times during each cycle.

Low-cycle fatigue analysis of a cooled copper combustion chamber

NASA Technical Reports Server (NTRS)

Miller, R. W.

1974-01-01

A three-dimensional finite element elastoplastic strain analysis was performed for the throat section of regeneratively cooled rocket engine combustion chamber. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the engine operating cycle. The strain range was used in conjunction with OFHC copper isothermal fatigue test data to predict engine low-cycle fatigue life. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen chamber which was fatigue tested to failure at the NASA Lewis Research Center.

Joint Recovery and Distribution System (JRaDS) Joint Capability Technology Demonstration (JCTD), Technical Manager’s Report

DTIC Science & Technology

2013-09-01

observed missions, JRaDS’ approach could lead to as few as five variants in the F3T. The F3T Systems can differ by the amount of payload they can carry...The system missions include vehicle and helicopter recovery operations , cargo loading and transportation and engineer equipment loading and...The 40T is equipped with a built-in 99 HP Kubota diesel APU to provide power to operate its electrical and hydraulic systems , including: the tilt

Real-Time Aircraft Engine-Life Monitoring

NASA Technical Reports Server (NTRS)

Klein, Richard

2014-01-01

This project developed an inservice life-monitoring system capable of predicting the remaining component and system life of aircraft engines. The embedded system provides real-time, inflight monitoring of the engine's thrust, exhaust gas temperature, efficiency, and the speed and time of operation. Based upon this data, the life-estimation algorithm calculates the remaining life of the engine components and uses this data to predict the remaining life of the engine. The calculations are based on the statistical life distribution of the engine components and their relationship to load, speed, temperature, and time.

Loss terms in free-piston Stirling engine models

NASA Technical Reports Server (NTRS)

Gordon, Lloyd B.

1992-01-01

Various models for free piston Stirling engines are reviewed. Initial models were developed primarily for design purposes and to predict operating parameters, especially efficiency. More recently, however, such models have been used to predict engine stability. Free piston Stirling engines have no kinematic constraints and stability may not only be sensitive to the load, but also to various nonlinear loss and spring constraints. The present understanding is reviewed of various loss mechanisms for free piston Stirling engines and how they have been incorporated into engine models is discussed.

Optimization of automotive Rankine cycle waste heat recovery under various engine operating condition

NASA Astrophysics Data System (ADS)

Punov, Plamen; Milkov, Nikolay; Danel, Quentin; Perilhon, Christelle; Podevin, Pierre; Evtimov, Teodossi

2017-02-01

An optimization study of the Rankine cycle as a function of diesel engine operating mode is presented. The Rankine cycle here, is studied as a waste heat recovery system which uses the engine exhaust gases as heat source. The engine exhaust gases parameters (temperature, mass flow and composition) were defined by means of numerical simulation in advanced simulation software AVL Boost. Previously, the engine simulation model was validated and the Vibe function parameters were defined as a function of engine load. The Rankine cycle output power and efficiency was numerically estimated by means of a simulation code in Python(x,y). This code includes discretized heat exchanger model and simplified model of the pump and the expander based on their isentropic efficiency. The Rankine cycle simulation revealed the optimum value of working fluid mass flow and evaporation pressure according to the heat source. Thus, the optimal Rankine cycle performance was obtained over the engine operating map.

Characterization of Hydrocarbon Emissions from Gasoline Direct-Injection Compression Ignition Engine Operating on a Higher Reactivity Gasoline Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Storey, John; Lewis, Samuel; Moses-DeBusk, Melanie

Low temperature combustion engine technologies are being investigated for high efficiency and low emissions. However, such engine technologies often produce higher engine-out hydrocarbon (HC) and carbon monoxide (CO) emissions, and their operating range is limited by the fuel properties. In this study, two different fuels, a US market gasoline containing 10% ethanol (RON 92 E10) and a higher reactivity gasoline (RON 80 E0), were compared on a Delphi’s second generation Gasoline Direct-Injection Compression Ignition (Gen 2.0 GDCI) multi-cylinder engine. The engine was evaluated at three operating points ranging from a light load condition (800 rpm/2 bar IMEP g) to mediummore » load conditions (1500 rpm/6 bar and 2000 rpm/10 bar IMEP g). The engine was equipped with two oxidation catalysts, between which was located the exhaust gas recirculation (EGR) inlet. Samples were taken at engine-out, between the catalysts, and at tailpipe locations. In addition, part of the raw exhaust was diluted and sampled for HC speciation. Canisters and sorbent membranes were used to collect volatile HCs and semi-volatile HCs, respectively. Di-nitrophenyl hydrazine (DNPH) cartridges were also used for collecting oxygenated species. Results showed overall lower HC emissions with the RON 80 E0 fuel compared to the RON 92 E10 fuel. For both fuels, the percentage of aromatic HCs was higher in the exhaust than in the fuels themselves. High engine-out aldehyde and ketone emissions were observed for both fuels. The reported HC speciation information can be useful for the development of a robust emission control system.« less

Characterization of Hydrocarbon Emissions from Gasoline Direct-Injection Compression Ignition Engine Operating on a Higher Reactivity Gasoline Fuel

DOE PAGES

Storey, John; Lewis, Samuel; Moses-DeBusk, Melanie; ...

2017-02-05

Low temperature combustion engine technologies are being investigated for high efficiency and low emissions. However, such engine technologies often produce higher engine-out hydrocarbon (HC) and carbon monoxide (CO) emissions, and their operating range is limited by the fuel properties. In this study, two different fuels, a US market gasoline containing 10% ethanol (RON 92 E10) and a higher reactivity gasoline (RON 80 E0), were compared on a Delphi’s second generation Gasoline Direct-Injection Compression Ignition (Gen 2.0 GDCI) multi-cylinder engine. The engine was evaluated at three operating points ranging from a light load condition (800 rpm/2 bar IMEP g) to mediummore » load conditions (1500 rpm/6 bar and 2000 rpm/10 bar IMEP g). The engine was equipped with two oxidation catalysts, between which was located the exhaust gas recirculation (EGR) inlet. Samples were taken at engine-out, between the catalysts, and at tailpipe locations. In addition, part of the raw exhaust was diluted and sampled for HC speciation. Canisters and sorbent membranes were used to collect volatile HCs and semi-volatile HCs, respectively. Di-nitrophenyl hydrazine (DNPH) cartridges were also used for collecting oxygenated species. Results showed overall lower HC emissions with the RON 80 E0 fuel compared to the RON 92 E10 fuel. For both fuels, the percentage of aromatic HCs was higher in the exhaust than in the fuels themselves. High engine-out aldehyde and ketone emissions were observed for both fuels. The reported HC speciation information can be useful for the development of a robust emission control system.« less

40 CFR 86.1910 - How must I prepare and test my in-use engines?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (including auxiliary loads such as air conditioning in the cab), normal ambient conditions, and the normal... engines? 86.1910 Section 86.1910 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... document that the owner/operator of the prospective test vehicle has a history of normally using the fuel...

a Thermoacoustically-Driven Pulse Tube Cryocryocooler Operating around 300HZ

NASA Astrophysics Data System (ADS)

Yu, G. Y.; Zhu, S. L.; Dai, W.; Luo, E. C.

2008-03-01

High frequency operation of the thermoacoustic cryocooler system, i.e. pulse tube cryocooler driven by thermoacoustic engine, leads to reduced size, which is quite attractive to small-scale cryogenic applications. In this work, a no-load coldhead temperature of 77.8 K is achieved on a 292 Hz pulse tube cryocooler driven by a standing-wave thermoacoustic engine with 3.92 MPa helium gas and 1750 W heat input. To improve thermal efficiency, a high frequency thermoacoustic-Stirling heat engine is also built to drive the same pulse tube cryocooler, and a no-load temperature of 109 K was obtained with 4.38 MPa helium gas, 292 Hz working frequency and 400W heating power. Ideas such as tapered resonators, acoustic amplifier tubes and simple thin tubes without reservoir are used to effectively suppress harmonic modes, amplify the acoustic pressure wave available to the pulse tube cryocooler and provide desired acoustic impedance for the pulse tube cryocooler, respectively. Comparison of systems with different thermoacoustic engines is made. Numerical simulations based on the linear thermoacoustic theory have also been done for comparison with experimental results, which shows reasonable agreement.

Fumigation of Alcohol in a Light Duty Automotive Diesel Engine

NASA Technical Reports Server (NTRS)

Broukhiyan, E. M. H.; Lestz, S. S.

1981-01-01

A light-duty automotive Diesel engine was fumigated with methanol in amounts up to 35% and 50% of the total fuel energy respectively in order to determine the effect of alcohol fumigation on engine performance at various operating conditons. Engine fuel efficiency, emissions, smoke, and the occurrence of severe knock were the parameters used to evaluate performance. Raw exhaust particulate and its soluble organic extract were screened for biological activity using the Ames Salmonella typhimurium assay. Results are given for a test matrix made up of twelve steady-state operating conditions. For all conditions except the 1/4 rack (light load) condition, modest thermal efficiency gains were noted upon ethanol fumigation. Methanol showed the same increase at 3/4 and full rack (high load) conditions. However, engine roughness or the occurrence of severe knock limited the maximum amount of alcohol that could be fumigated. Brake specific nitrogen oxide concentrations were found to decrease for all ethanol conditions tested. Oxides of nitrogen emissions, on a volume basis, decreased for all alcohol conditions tested. Based on the limited particulate data analyzed, it appears that ethanol fumigation, like methanol fumigation, while lowering the mass of particulated emitted, does enhance the biological activity of that particulate.

CELCAP: A Computer Model for Cogeneration System Analysis

NASA Technical Reports Server (NTRS)

1985-01-01

A description of the CELCAP cogeneration analysis program is presented. A detailed description of the methodology used by the Naval Civil Engineering Laboratory in developing the CELCAP code and the procedures for analyzing cogeneration systems for a given user are given. The four engines modeled in CELCAP are: gas turbine with exhaust heat boiler, diesel engine with waste heat boiler, single automatic-extraction steam turbine, and back-pressure steam turbine. Both the design point and part-load performances are taken into account in the engine models. The load model describes how the hourly electric and steam demand of the user is represented by 24 hourly profiles. The economic model describes how the annual and life-cycle operating costs that include the costs of fuel, purchased electricity, and operation and maintenance of engines and boilers are calculated. The CELCAP code structure and principal functions of the code are described to how the various components of the code are related to each other. Three examples of the application of the CELCAP code are given to illustrate the versatility of the code. The examples shown represent cases of system selection, system modification, and system optimization.

Aircraft engine hot section technology: An overview of the HOST Project

NASA Technical Reports Server (NTRS)

Sokolowski, Daniel E.; Hirschberg, Marvin H.

1990-01-01

NASA sponsored the Turbine Engine Hot Section (HOST) project to address the need for improved durability in advanced aircraft engine combustors and turbines. Analytical and experimental activities aimed at more accurate prediction of the aerothermal environment, the thermomechanical loads, the material behavior and structural responses to loads, and life predictions for cyclic high temperature operation were conducted from 1980 to 1987. The project involved representatives from six engineering disciplines who are spread across three work disciplines - industry, academia, and NASA. The HOST project not only initiated and sponsored 70 major activities, but also was the keystone in joining the multiple disciplines and work sectors to focus on critical research needs. A broad overview of the project is given along with initial indications of the project's impact.

Simulations of the Fuel Economy and Emissions of Hybrid Transit Buses over Planned Local Routes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Zhiming; LaClair, Tim J; Daw, C Stuart

2014-01-01

We present simulated fuel economy and emissions city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but trends inmore » the tailpipe (post-aftertreatment) emissions involve more complex interactions that significantly depend on motor size and drive cycle details.« less

Application for managing model-based material properties for simulation-based engineering

DOEpatents

Hoffman, Edward L [Alameda, CA

2009-03-03

An application for generating a property set associated with a constitutive model of a material includes a first program module adapted to receive test data associated with the material and to extract loading conditions from the test data. A material model driver is adapted to receive the loading conditions and a property set and operable in response to the loading conditions and the property set to generate a model response for the material. A numerical optimization module is adapted to receive the test data and the model response and operable in response to the test data and the model response to generate the property set.

Engineering aspects of design and integration of ECE diagnostic in ITER

DOE PAGES

Udintsev, V. S.; Taylor, G.; Pandya, H. K.B.; ...

2015-03-12

ITER ECE diagnostic [1] needs not only to meet measurement requirements, but also to withstand various loads, such as electromagnetic, mechanical, neutronic and thermal, and to be protected from stray ECH radiation at 170 GHz and other millimeter wave emission, like Collective Thomson scattering which is planned to operate at 60 GHz. Same or similar loads will be applied to other millimetre-wave diagnostics [2], located both in-vessel and in-port plugs. These loads must be taken into account throughout the design phases of the ECE and other microwave diagnostics to ensure their structural integrity and maintainability. The integration of microwave diagnosticsmore » with other ITER systems is another challenging activity which is currently ongoing through port integration and in-vessel integration work. Port Integration has to address the maintenance and the safety aspects of diagnostics, too. Engineering solutions which are being developed to support and to operate ITER ECE diagnostic, whilst complying with safety and maintenance requirements, are discussed in this paper.« less

High-Temperature (1000 F) Magnetic Thrust Bearing Test Rig Completed and Operational

NASA Technical Reports Server (NTRS)

Montague, Gerald T.

2005-01-01

Large axial loads are induced on the rolling element bearings of a gas turbine. To extend bearing life, designers use pneumatic balance pistons to reduce the axial load on the bearings. A magnetic thrust bearing could replace the balance pistons to further reduce the axial load. To investigate this option, the U.S. Army Research Laboratory, the NASA Glenn Research Center, and Texas A&M University designed and fabricated a 7-in.- diameter magnetic thrust bearing to operate at 1000 F and 30,000 rpm, with a 1000-lb load capacity. This research was funded through a NASA Space Technology Transfer Act with Allison Advance Development Company under the Ultra-Efficient Engine Technology (UEET) Intelligent Propulsion Systems Foundation Technology project.

Hierarchical Discrete Event Supervisory Control of Aircraft Propulsion Systems

NASA Technical Reports Server (NTRS)

Yasar, Murat; Tolani, Devendra; Ray, Asok; Shah, Neerav; Litt, Jonathan S.

2004-01-01

This paper presents a hierarchical application of Discrete Event Supervisory (DES) control theory for intelligent decision and control of a twin-engine aircraft propulsion system. A dual layer hierarchical DES controller is designed to supervise and coordinate the operation of two engines of the propulsion system. The two engines are individually controlled to achieve enhanced performance and reliability, necessary for fulfilling the mission objectives. Each engine is operated under a continuously varying control system that maintains the specified performance and a local discrete-event supervisor for condition monitoring and life extending control. A global upper level DES controller is designed for load balancing and overall health management of the propulsion system.

Systems Engineering Management Procedures

DTIC Science & Technology

1966-03-10

load -..................................................... tch 2 1t55 𔄃 Trade Study-Companson ,f Methods for Measuring Quantities of Loaded... method of system operation and the ancillary equipment required such as instru- system elements is a highly involved process mentation. depot tooling...Installation and checkout. MiGI-Maintenance g-round equipment. IM-Item manager. NIP-Materiel improvement proipct. indenturo-A method of showing relationships

40 CFR 86.884-7 - Dynamometer operation cycle for smoke emission tests.

Code of Federal Regulations, 2014 CFR

2014-07-01

... provide the speed and load necessary to comply with the heavy-duty “curb idle” definition per § 86.084-2..., and held in, the fully open position. The inertia of the engine and the dynamometer, or alternately a... mode, motoring assist may be used to offset excessive dynamometer inertia load when necessary. No...

40 CFR 86.884-7 - Dynamometer operation cycle for smoke emission tests.

Code of Federal Regulations, 2012 CFR

2012-07-01

... be set to provide the speed and load necessary to comply with the heavy-duty “curb idle” definition..., and held in, the fully open position. The inertia of the engine and the dynamometer, or alternately a... mode, motoring assist may be used to offset excessive dynamometer inertia load when necessary. No...

40 CFR 86.884-7 - Dynamometer operation cycle for smoke emission tests.

Code of Federal Regulations, 2013 CFR

2013-07-01

... be set to provide the speed and load necessary to comply with the heavy-duty “curb idle” definition..., and held in, the fully open position. The inertia of the engine and the dynamometer, or alternately a... mode, motoring assist may be used to offset excessive dynamometer inertia load when necessary. No...

40 CFR 86.884-7 - Dynamometer operation cycle for smoke emission tests.

Code of Federal Regulations, 2011 CFR

2011-07-01

... be set to provide the speed and load necessary to comply with the heavy-duty “curb idle” definition..., and held in, the fully open position. The inertia of the engine and the dynamometer, or alternately a... mode, motoring assist may be used to offset excessive dynamometer inertia load when necessary. No...

Environmental and High-Strain Rate effects on composites for engine applications

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Smith, G. T.

1982-01-01

The Lewis Research Center is conducting a series of programs intended to investigate and develop the application of composite materials to structural components for turbojet engines. A significant part of that effort is directed to establishing resistance, defect growth, and strain rate characteristics of composite materials over the wide range of environmental and load conditions found in commercial turbojet engine operations. Both analytical and experimental efforts are involved.

Space Shuttle Main Engine Off-Nominal Low Power Level Operation

NASA Technical Reports Server (NTRS)

Bradley, Michael

1997-01-01

This paper describes Rocketdyne's successful analysis and demonstration of the Space Shuttle Main Engine (SSME) operation at off-nominal power levels during Reusable Launch Vehicle (RLV) evaluation tests. The nominal power level range for the SSME is from 65% rated power level (RPL) to 109% RPL. Off-nominal power levels incrementally demonstrated were: 17% RPL, 22% RPL, 27% RPL, 40% RPL, 45% RPL, and 50% RPL. Additional achievements during low power operation included: use of a hydrostatic bearing High Pressure Oxidizer Turbopump (HPOTP), nominal High Pressure Fuel Turbopump (HPFTP) first rotor critical speed operation, combustion stability at low power levels, and refined definition of nozzle flow separation heat loads.

40 CFR 91.404 - Test procedure overview.

Code of Federal Regulations, 2014 CFR

2014-07-01

... conducted on an engine dynamometer or equivalent load and speed measurement device. The exhaust gases... with an exponential relationship between torque and speed which span the typical operating range of...

Initial testing of a variable-stroke Stirling engine

NASA Technical Reports Server (NTRS)

Thieme, L. G.

1985-01-01

In support of the U.S. Department of Energy's Stirling Engine Highway Vehicle Systems Program, NASA Lewis Research Center is evaluating variable-stroke control for Stirling engines. The engine being tested is the Advenco Stirling engine; this engine was manufactured by Philips Research Laboratories of the Netherlands and uses a variable-angle swash-plate drive to achieve variable stroke operation. The engine is described, initial steady-state test data taken at Lewis are presented, a major drive system failure and subsequent modifications are described. Computer simulation results are presented to show potential part-load efficiency gains with variable-stroke control.

Real-time analysis of organic compounds in ship engine aerosol emissions using resonance-enhanced multiphoton ionisation and proton transfer mass spectrometry.

PubMed

Radischat, Christian; Sippula, Olli; Stengel, Benjamin; Klingbeil, Sophie; Sklorz, Martin; Rabe, Rom; Streibel, Thorsten; Harndorf, Horst; Zimmermann, Ralf

2015-08-01

Organic combustion aerosols from a marine medium-speed diesel engine, capable to run on distillate (diesel fuel) and residual fuels (heavy fuel oil), were investigated under various operating conditions and engine parameters. The online chemical characterisation of the organic components was conducted using a resonance-enhanced multiphoton ionisation time-of-flight mass spectrometer (REMPI TOF MS) and a proton transfer reaction-quadrupole mass spectrometer (PTR-QMS). Oxygenated species, alkenes and aromatic hydrocarbons were characterised. Especially the aromatic hydrocarbons and their alkylated derivatives were very prominent in the exhaust of both fuels. Emission factors of known health-hazardous compounds (e.g. mono- and poly-aromatic hydrocarbons) were calculated and found in higher amounts for heavy fuel oil (HFO) at typical engine loadings. Lower engine loads lead in general to increasing emissions for both fuels for almost every compound, e.g. naphthalene emissions varied for diesel fuel exhaust between 0.7 mg/kWh (75 % engine load, late start of injection (SOI)) and 11.8 mg/kWh (10 % engine load, late SOI) and for HFO exhaust between 3.3 and 60.5 mg/kWh, respectively. Both used mass spectrometric techniques showed that they are particularly suitable methods for online monitoring of combustion compounds and very helpful for the characterisation of health-relevant substances. Graphical abstract Three-dimensional REMPI data of organic species in diesel fuel and heavy fuel oil exhaust.

Shuttle Program Loads Integration: Going From Concept to Operations and Staying Successful

NASA Technical Reports Server (NTRS)

Bernstein, Karen; James, George; Mackey, alden; Murphy, Neil C.; Brolliar, Steve

2011-01-01

From the beginning of the Shuttle Program to its end, integrated loads and dynamics analyses and tests have been critical in shaping the vehicle design and operational decisions for NASA and its customers. Starting with scaled models and simple mathematical simulations of the structural dynamics, engineers defined the required structural stiffness and predicted the limit loads for each element of the system. Early structural tests provided reasonable confidence that the models and predictions were good. The first launch of the Space Shuttle brought surprises, though, when the ignition overpressure event caused a forward fuel tank support strut to buckle, among several unexpected effects. The launch pad and other ground equipment became an integral part of the system integration, especially where the acoustic and pressure environments of ignition and lift-off were concerned. Following the Challenger accident, operating limits were changed in response to new understandings of how the integrated system performed. Controlling loads while maximizing performance was a key tenet of the Performance Enhancement design process, which enabled construction of the International Space Station. During the return to flight after the Columbia accident, engineers grew to understand that loads during the roll maneuver were also important to the vehicle s structural margin and life. At this point the crawler transport from the Vehicle Assembly Building to the launch pad also became a part of the integrated loads analysis. Even in the last years of the Space Shuttle Program, new data still provided interesting insights into this complicated and fascinating spaceship. This paper will present some examples of the important findings by the team of specialists that supported the Integrated Loads and Dynamics Panel for the Space Shuttle Program.

Performance and emissions characteristics of aqueous alcohol fumes in a DI diesel engine

NASA Technical Reports Server (NTRS)

Heisey, J. B.; Lestz, S. S.

1981-01-01

A single cylinder DI Diesel engine was fumigated with ethanol and methanol in amounts up to 55% of the total fuel energy. The effects of aqueous alcohol fumigation on engine thermal efficiency, combustion intensity and gaseous exhaust emissions were determined. Assessment of changes in the biological activity of raw particulate and its soluble organic fraction were also made using the Salmonella typhimurium test. Alcohol fumigation improved thermal efficiency slightly at moderate and heavy loads, but increased ignition delay at all operating conditions. Carbon monoxide and unburned hydrocarbon emission generally increased with alcohol fumigation and showed no dependence on alcohol type or quality. Oxide of nitrogen emission showed a strong dependence on alcohol quality; relative emission levels decreased with increasing water content of the fumigant. Particulate mass loading rates were lower for ethanol fueled conditions. However, the biological activity of both the raw particulate and its soluble organic fraction was enhanced by ethanol fumigation at most operating conditions.

49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

Code of Federal Regulations, 2010 CFR

2010-10-01

... stationary locomotives at load cells: (1) Each noise emission test shall begin after the engine of the locomotive has attained the normal cooling water operating temperature as prescribed by the locomotive manufacturer. (2) Noise emission testing in idle or maximum throttle setting shall start after a 40 second...

Experimental Research and Method for Calculation of 'Upsetting-with-Buckling' Load at the Impression-Free (Dieless) Preforming of Workpiece

NASA Astrophysics Data System (ADS)

Kukhar, Volodymir; Artiukh, Victor; Prysiazhnyi, Andrii; Pustovgar, Andrey

2018-03-01

This paper presents the results of experimental studies of load characteristic changes during the upsetting of high billets with the upsetting ratio (height to diameter ratio) from 3.0 to 6.0, which is followed by buckling. Such pass is an effective way of preforming the workpiece for production of forgings with a bended axis or dual forming, and belongs to impression-free (dieless) operation of bulk forming. Based on the experimental data analysis, an engineering method for calculation of workpiece pre-forming load as a maximum buckling force has been developed. The analysis of the obtained data confirmed the possibility of performing of this pre-forming operation on the main forging equipment, since the load of shaping by buckling does not exceed the load of the dieforging.

Vande Hei exercises on COLBERT/T2 Treadmill

NASA Image and Video Library

2017-09-23

iss053e040103 (ept. 23, 2017) --- Astronaut Mark Vande Hei, Expedition 53 Flight Engineer, exercises on the COLBERT (Combined Operational Load Bearing External Resistance Treadmill) in the Tranquility module.

Composite load spectra for select space propulsion structural components

NASA Technical Reports Server (NTRS)

Newell, J. F.; Kurth, R. E.; Ho, H.

1986-01-01

A multiyear program is performed with the objective to develop generic load models with multiple levels of progressive sophistication to simulate the composite (combined) load spectra that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades, and liquid oxygen (LOX) posts. Progress of the first year's effort includes completion of a sufficient portion of each task -- probabilistic models, code development, validation, and an initial operational code. This code has from its inception an expert system philosophy that could be added to throughout the program and in the future. The initial operational code is only applicable to turbine blade type loadings. The probabilistic model included in the operational code has fitting routines for loads that utilize a modified Discrete Probabilistic Distribution termed RASCAL, a barrier crossing method and a Monte Carlo method. An initial load model was developed by Battelle that is currently used for the slowly varying duty cycle type loading. The intent is to use the model and related codes essentially in the current form for all loads that are based on measured or calculated data that have followed a slowly varying profile.

Utility gas turbine combustor viewing system: Volume 2, Engine operating envelope test: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morey, W.W.

1988-12-01

This report summarizes the development and field testing of a combustor viewing probe (CVP) as a flame diagnostic monitor for utility gas turbine engines. The prototype system is capable of providing a visual record of combustor flame images, recording flame spectral data, analyzing image and spectral data, and diagnosing certain engine malfunctions. The system should provide useful diagnostic information to utility plant operators, and reduced maintenance costs. The field tests demonstrated the ability of the CVP to monitor combustor flame condition and to relate changes in the engine operation with variations in the flame signature. Engine light off, run upmore » to full speed, the addition of load, and the effect of water injection for NO/sub x/ control could easily be identified on the video monitor. The viewing probe was also valuable in identifying hard startups and shutdowns, as well as transient effects that can seriously harm the engine.« less

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.

Large gas injection engine nearing completion in Japan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, K.

1994-04-01

One of the world's largest diesel engines to be operated on methane gas under pressure injection is now nearing completion at the Chiba works of Mitsui, in Japan. The MAN B W-designed 12K80MC-GI-S engine - built by Mitsui Engineering and Shipbuilding Co., in Tamano, Japan - will develop a total of 40,680 kW when operating at 103.4 r/min. It will drive an electrical generator of 39,740 kW output to provide power to Mitsui's Chiba works. The arrangement will be such that excess electrical energy can be taken into the local electrical supply system. Since the engine will be operating inmore » an area of strict emission control, the exhaust gas from the engine will pass through a large SCR before reaching the main chimney. Low-sulfur diesel oil will be used as the pilot fuel, and will amount to only eight percent of the fuel charge at full load. The MC-GI series of engines can be used as main propulsion engines in LNG carriers or stationary power plants. 3 figs.« less

Dynamic Loads Generation for Multi-Point Vibration Excitation Problems

NASA Technical Reports Server (NTRS)

Shen, Lawrence

2011-01-01

A random-force method has been developed to predict dynamic loads produced by rocket-engine random vibrations for new rocket-engine designs. The method develops random forces at multiple excitation points based on random vibration environments scaled from accelerometer data obtained during hot-fire tests of existing rocket engines. This random-force method applies random forces to the model and creates expected dynamic response in a manner that simulates the way the operating engine applies self-generated random vibration forces (random pressure acting on an area) with the resulting responses that we measure with accelerometers. This innovation includes the methodology (implementation sequence), the computer code, two methods to generate the random-force vibration spectra, and two methods to reduce some of the inherent conservatism in the dynamic loads. This methodology would be implemented to generate the random-force spectra at excitation nodes without requiring the use of artificial boundary conditions in a finite element model. More accurate random dynamic loads than those predicted by current industry methods can then be generated using the random force spectra. The scaling method used to develop the initial power spectral density (PSD) environments for deriving the random forces for the rocket engine case is based on the Barrett Criteria developed at Marshall Space Flight Center in 1963. This invention approach can be applied in the aerospace, automotive, and other industries to obtain reliable dynamic loads and responses from a finite element model for any structure subject to multipoint random vibration excitations.

Optimized scalar promotion with load and splat SIMD instructions

DOEpatents

Eichenberger, Alexander E; Gschwind, Michael K; Gunnels, John A

2013-10-29

Mechanisms for optimizing scalar code executed on a single instruction multiple data (SIMD) engine are provided. Placement of vector operation-splat operations may be determined based on an identification of scalar and SIMD operations in an original code representation. The original code representation may be modified to insert the vector operation-splat operations based on the determined placement of vector operation-splat operations to generate a first modified code representation. Placement of separate splat operations may be determined based on identification of scalar and SIMD operations in the first modified code representation. The first modified code representation may be modified to insert or delete separate splat operations based on the determined placement of the separate splat operations to generate a second modified code representation. SIMD code may be output based on the second modified code representation for execution by the SIMD engine.

Optimized scalar promotion with load and splat SIMD instructions

DOEpatents

Eichenberger, Alexandre E [Chappaqua, NY; Gschwind, Michael K [Chappaqua, NY; Gunnels, John A [Yorktown Heights, NY

2012-08-28

Mechanisms for optimizing scalar code executed on a single instruction multiple data (SIMD) engine are provided. Placement of vector operation-splat operations may be determined based on an identification of scalar and SIMD operations in an original code representation. The original code representation may be modified to insert the vector operation-splat operations based on the determined placement of vector operation-splat operations to generate a first modified code representation. Placement of separate splat operations may be determined based on identification of scalar and SIMD operations in the first modified code representation. The first modified code representation may be modified to insert or delete separate splat operations based on the determined placement of the separate splat operations to generate a second modified code representation. SIMD code may be output based on the second modified code representation for execution by the SIMD engine.

Analysis of possibilities of waste heat recovery in off-road vehicles

NASA Astrophysics Data System (ADS)

Wojciechowski, K. T.; Zybala, R.; Leszczynski, J.; Nieroda, P.; Schmidt, M.; Merkisz, J.; Lijewski, P.; Fuc, P.

2012-06-01

The paper presents the preliminary results of the waste heat recovery investigations for an agricultural tractor engine (7.4 dm3) and excavator engine (7.2 dm3) in real operating conditions. The temperature of exhaust gases and exhaust mass flow rate has been measured by precise portable exhaust emissions analyzer SEMTECH DS (SENSORS Inc.). The analysis shows that engines of tested vehicles operate approximately at constant speed and load. The average temperature of exhaust gases is in the range from 300 to 400 °C for maximum gas mass flows of 1100 kg/h and 1400 kg/h for tractor and excavator engine respectively. Preliminary tests show that application of TEGs in tested off-road vehicles offers much more beneficial conditions for waste heat recovery than in case of automotive engines.

Integrating Phase-Change Materials into Automotive Thermoelectric Generators

NASA Astrophysics Data System (ADS)

Klein Altstedde, Mirko; Rinderknecht, Frank; Friedrich, Horst

2014-06-01

Because the heat emitted by conventional combustion-engine vehicles during operation has highly transient properties, automotive thermoelectric generators (TEG) are intended for a particular operating state (design point). This, however, leads to two problems. First, whenever the combustion engine runs at low load, the maximum operating temperature cannot be properly utilised; second, a combustion engine at high load requires partial diversion of exhaust gas away from the TEG to protect the thermoelectric modules. An attractive means of stabilising dynamic exhaust behaviour (thereby keeping the TEG operating status at the design point for as long as possible) is use of latent heat storage, also known as phase-change materials (PCM). By positioning PCM between module and exhaust heat conduit, and choosing a material with a phase-change temperature matching the module's optimum operating temperature, it can be used as heat storage. This paper presents results obtained during examination of the effect of integration of latent heat storage on the potential of automotive TEG to convert exhaust heat. The research resulted in the development of a concept based on the initial integration idea, followed by proof of concept by use of a specially created prototype. In addition, the potential amount of energy obtained by use of a PCM-equipped TEG was calculated. The simulations indicated a significant increase in electrical energy was obtained in the selected test cycle.

Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine

NASA Technical Reports Server (NTRS)

Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.

1987-01-01

A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

Hige Compression Ratio Turbo Gasoline Engine Operation Using Alcohol Enhancement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heywood, John; Jo, Young Suk; Lewis, Raymond

The overall objective of this project was to quantify the potential for improving the performance and efficiency of gasoline engine technology by use of alcohols to suppress knock. Knock-free operation is obtained by direct injection of a second “anti-knock” fuel such as ethanol, which suppresses knock when, with gasoline fuel, knock would occur. Suppressing knock enables increased turbocharging, engine downsizing, and use of higher compression ratios throughout the engine’s operating map. This project combined engine testing and simulation to define knock onset conditions, with different mixtures of gasoline and alcohol, and with this information quantify the potential for improving themore » efficiency of turbocharged gasoline spark-ignition engines, and the on-vehicle fuel consumption reductions that could then be realized. The more focused objectives of this project were therefore to: Determine engine efficiency with aggressive turbocharging and downsizing and high compression ratio (up to a compression ratio of 13.5:1) over the engine’s operating range; Determine the knock limits of a turbocharged and downsized engine as a function of engine speed and load; Determine the amount of the knock-suppressing alcohol fuel consumed, through the use of various alcohol-gasoline and alcohol-water gasoline blends, for different driving cycles, relative to the gasoline consumed; Determine implications of using alcohol-boosted engines, with their higher efficiency operation, in both light-duty and medium-duty vehicle sectors.« less

Real-world exhaust temperature profiles of on-road heavy-duty diesel vehicles equipped with selective catalytic reduction.

PubMed

Boriboonsomsin, Kanok; Durbin, Thomas; Scora, George; Johnson, Kent; Sandez, Daniel; Vu, Alexander; Jiang, Yu; Burnette, Andrew; Yoon, Seungju; Collins, John; Dai, Zhen; Fulper, Carl; Kishan, Sandeep; Sabisch, Michael; Jackson, Doug

2018-09-01

On-road heavy-duty diesel vehicles are a major contributor of oxides of nitrogen (NO x ) emissions. In the US, many heavy-duty diesel vehicles employ selective catalytic reduction (SCR) technology to meet the 2010 emission standard for NO x . Typically, SCR needs to be at least 200°C before a significant level of NO x reduction is achieved. However, this SCR temperature requirement may not be met under some real-world operating conditions, such as during cold starts, long idling, or low speed/low engine load driving activities. The frequency of vehicle operation with low SCR temperature varies partly by the vehicle's vocational use. In this study, detailed vehicle and engine activity data were collected from 90 heavy-duty vehicles involved in a range of vocations, including line haul, drayage, construction, agricultural, food distribution, beverage distribution, refuse, public work, and utility repair. The data were used to create real-world SCR temperature and engine load profiles and identify the fraction of vehicle operating time that SCR may not be as effective for NO x control. It is found that the vehicles participated in this study operate with SCR temperature lower than 200°C for 11-70% of the time depending on their vocation type. This implies that real-world NO x control efficiency could deviate from the control efficiency observed during engine certification. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis of unregulated emissions from an off-road diesel engine during realistic work operations

NASA Astrophysics Data System (ADS)

Lindgren, Magnus; Arrhenius, Karine; Larsson, Gunnar; Bäfver, Linda; Arvidsson, Hans; Wetterberg, Christian; Hansson, Per-Anders; Rosell, Lars

2011-09-01

Emissions from vehicle diesel engines constitute a considerable share of anthropogenic emissions of pollutants, including many non-regulated compounds such as aromatic hydrocarbons and alkenes. One way to reduce these emissions might be to use fuels with low concentrations of aromatic hydrocarbons, such as Fischer-Tropsch (F-T) diesels. Therefore this study compared Swedish Environmental Class 1 diesel (EC1) with the F-T diesel fuel Ecopar™ in terms of emissions under varied conditions (steady state, controlled transients and realistic work operations) in order to identify factors influencing emissions in actual operation. Using F-T diesel reduced emissions of aromatic hydrocarbons, but not alkenes. Emissions were equally dependent on work operation character (load, engine speed, occurrence of transients) for both fuels. There were indications that the emissions originated from unburnt fuel, rather than from combustion products.

DOE/NASA Mod-0 100KW wind turbine test results

NASA Technical Reports Server (NTRS)

Glasgow, J. C.

1978-01-01

The Wind Turbine demonstrates the capability of automatic unattended operation, including startup, achieving synchronism, and shutdown as dictated by wind conditions. During the course of these operations, a wealth of engineering data was generated. Some of the data which is associated with rotor and machine dynamics problems encountered, and the machine modifications incorporated as a solution are presented. These include high blade loads due to tower shadow, excessive nacelle yawing motion, and power oscillations. The results of efforts to correlate measured wind velocity with power output and wind turbine loads are also discussed.

Orbit transfer rocket engine technology program. Phase 2: Advanced engine study

NASA Technical Reports Server (NTRS)

Erickson, C.; Martinez, A.; Hines, B.

1987-01-01

In Phase 2 of the Advanced Engine Study, the Failure Modes and Effects Analysis (FMEA) maintenance-driven engine design, preliminary maintenance plan, and concept for space operable disconnects generated in Phase 1 were further developed. Based on the results of the vehicle contractors Orbit Transfer Vehicle (OTV) Concept Definition and System Analysis Phase A studies, minor revisions to the engine design were made. Additional refinements in the engine design were identified through further engine concept studies. These included an updated engine balance incorporating experimental heat transfer data from the Enhanced Heat Load Thrust Chamber Study and a Rao optimum nozzle contour. The preliminary maintenance plan of Phase 1 was further developed through additional studies. These included a compilation of critical component lives and life limiters and a review of the Space Shuttle Main Engine (SSME) operations and maintenance manual in order to begin outlining the overall maintenance procedures for the Orbit Transfer Vehicle Engine and identifying technology requirements for streamlining space-based operations. Phase 2 efforts also provided further definition to the advanced fluid coupling devices including the selection and preliminary design of a preferred concept and a preliminary test plan for its further development.

Autonomous Cryogenics Loading Operations Simulation Software: Knowledgebase Autonomous Test Engineer

NASA Technical Reports Server (NTRS)

Wehner, Walter S., Jr.

2013-01-01

Working on the ACLO (Autonomous Cryogenics Loading Operations) project I have had the opportunity to add functionality to the physics simulation software known as KATE (Knowledgebase Autonomous Test Engineer), create a new application allowing WYSIWYG (what-you-see-is-what-you-get) creation of KATE schematic files and begin a preliminary design and implementation of a new subsystem that will provide vision services on the IHM (Integrated Health Management) bus. The functionality I added to KATE over the past few months includes a dynamic visual representation of the fluid height in a pipe based on number of gallons of fluid in the pipe and implementing the IHM bus connection within KATE. I also fixed a broken feature in the system called the Browser Display, implemented many bug fixes and made changes to the GUI (Graphical User Interface).

Progress of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting Radial Growth on a Rotating Disk

NASA Technical Reports Server (NTRS)

Clem, Michelle M.; Abdul-Aziz, Ali; Woike, Mark R.; Fralick, Gustave C.

2015-01-01

The modern turbine engine operates in a harsh environment at high speeds and is repeatedly exposed to combined high mechanical and thermal loads. The cumulative effects of these external forces lead to high stresses and strains on the engine components, such as the rotating turbine disks, which may eventually lead to a catastrophic failure if left undetected. The operating environment makes it difficult to use conventional strain gauges, therefore, non-contact strain measurement techniques is of interest to NASA and the turbine engine community. This presentation describes one such approach; the use of cross correlation analysis to measure strain experienced by the engine turbine disk with the goal of assessing potential faults and damage.

Advanced active health monitoring system of liquid rocket engines

NASA Astrophysics Data System (ADS)

Qing, Xinlin P.; Wu, Zhanjun; Beard, Shawn; Chang, Fu-Kuo

2008-11-01

An advanced SMART TAPE system has been developed for real-time in-situ monitoring and long term tracking of structural integrity of pressure vessels in liquid rocket engines. The practical implementation of the structural health monitoring (SHM) system including distributed sensor network, portable diagnostic hardware and dedicated data analysis software is addressed based on the harsh operating environment. Extensive tests were conducted on a simulated large booster LOX-H2 engine propellant duct to evaluate the survivability and functionality of the system under the operating conditions of typical liquid rocket engines such as cryogenic temperature, vibration loads. The test results demonstrated that the developed SHM system could survive the combined cryogenic temperature and vibration environments and effectively detect cracks as small as 2 mm.

Identification of secondary aerosol precursors emitted by an aircraft turbofan

NASA Astrophysics Data System (ADS)

Kılıç, Doğuşhan; El Haddad, Imad; Brem, Benjamin T.; Bruns, Emily; Bozetti, Carlo; Corbin, Joel; Durdina, Lukas; Huang, Ru-Jin; Jiang, Jianhui; Klein, Felix; Lavi, Avi; Pieber, Simone M.; Rindlisbacher, Theo; Rudich, Yinon; Slowik, Jay G.; Wang, Jing; Baltensperger, Urs; Prévôt, Andre S. H.

2018-05-01

Oxidative processing of aircraft turbine-engine exhausts was studied using a potential aerosol mass (PAM) chamber at different engine loads corresponding to typical flight operations. Measurements were conducted at an engine test cell. Organic gases (OGs) and particle emissions pre- and post-PAM were measured. A suite of instruments, including a proton-transfer-reaction mass spectrometer (PTR-MS) for OGs, a multigas analyzer for CO, CO2, NOx, and an aerosol mass spectrometer (AMS) for nonrefractory particulate matter (NR-PM1) were used. Total aerosol mass was dominated by secondary aerosol formation, which was approximately 2 orders of magnitude higher than the primary aerosol. The chemical composition of both gaseous and particle emissions were also monitored at different engine loads and were thrust-dependent. At idling load (thrust 2.5-7 %), more than 90 % of the secondary particle mass was organic and could mostly be explained by the oxidation of gaseous aromatic species, e.g., benzene; toluene; xylenes; tri-, tetra-, and pentamethyl-benzene; and naphthalene. The oxygenated-aromatics, e.g., phenol, furans, were also included in this aromatic fraction and their oxidation could alone explain up to 25 % of the secondary organic particle mass at idling loads. The organic fraction decreased with thrust level, while the inorganic fraction increased. At an approximated cruise load sulfates comprised 85 % of the total secondary particle mass.

Cryogenic, high speed, turbopump bearing cooling requirements

NASA Technical Reports Server (NTRS)

Dolan, Fred J.; Gibson, Howard G.; Cannon, James L.; Cody, Joe C.

1988-01-01

Although the Space Shuttle Main Engine (SSME) has repeatedly demonstrated the capability to perform during launch, the High Pressure Oxidizer Turbopump (HPOTP) main shaft bearings have not met their 7.5 hour life requirement. A tester is being employed to provide the capability of subjecting full scale bearings and seals to speeds, loads, propellants, temperatures, and pressures which simulate engine operating conditions. The tester design permits much more elaborate instrumentation and diagnostics than could be accommodated in an SSME turbopump. Tests were made to demonstrate the facilities; and the devices' capabilities, to verify the instruments in its operating environment and to establish a performance baseline for the flight type SSME HPOTP Turbine Bearing design. Bearing performance data from tests are being utilized to generate: (1) a high speed, cryogenic turbopump bearing computer mechanical model, and (2) a much improved, very detailed thermal model to better understand bearing internal operating conditions. Parametric tests were also made to determine the effects of speed, axial loads, coolant flow rate, and surface finish degradation on bearing performance.

The performance of a piezoelectric-sensor-based SHM system under a combined cryogenic temperature and vibration environment

NASA Astrophysics Data System (ADS)

Qing, Xinlin P.; Beard, Shawn J.; Kumar, Amrita; Sullivan, Kevin; Aguilar, Robert; Merchant, Munir; Taniguchi, Mike

2008-10-01

A series of tests have been conducted to determine the survivability and functionality of a piezoelectric-sensor-based active structural health monitoring (SHM) SMART Tape system under the operating conditions of typical liquid rocket engines such as cryogenic temperature and vibration loads. The performance of different piezoelectric sensors and a low temperature adhesive under cryogenic temperature was first investigated. The active SHM system for liquid rocket engines was exposed to flight vibration and shock environments on a simulated large booster LOX-H2 engine propellant duct conditioned to cryogenic temperatures to evaluate the physical robustness of the built-in sensor network as well as operational survivability and functionality. Test results demonstrated that the developed SMART Tape system can withstand operational levels of vibration and shock energy on a representative rocket engine duct assembly, and is functional under the combined cryogenic temperature and vibration environment.

Comparative Study of Different Methods for Soot Sensing and Filter Monitoring in Diesel Exhausts.

PubMed

Feulner, Markus; Hagen, Gunter; Hottner, Kathrin; Redel, Sabrina; Müller, Andreas; Moos, Ralf

2017-02-18

Due to increasingly tighter emission limits for diesel and gasoline engines, especially concerning particulate matter emissions, particulate filters are becoming indispensable devices for exhaust gas after treatment. Thereby, for an efficient engine and filter control strategy and a cost-efficient filter design, reliable technologies to determine the soot load of the filters and to measure particulate matter concentrations in the exhaust gas during vehicle operation are highly needed. In this study, different approaches for soot sensing are compared. Measurements were conducted on a dynamometer diesel engine test bench with a diesel particulate filter (DPF). The DPF was monitored by a relatively new microwave-based approach. Simultaneously, a resistive type soot sensor and a Pegasor soot sensing device as a reference system measured the soot concentration exhaust upstream of the DPF. By changing engine parameters, different engine out soot emission rates were set. It was found that the microwave-based signal may not only indicate directly the filter loading, but by a time derivative, the engine out soot emission rate can be deduced. Furthermore, by integrating the measured particulate mass in the exhaust, the soot load of the filter can be determined. In summary, all systems coincide well within certain boundaries and the filter itself can act as a soot sensor.

Comparative Study of Different Methods for Soot Sensing and Filter Monitoring in Diesel Exhausts

PubMed Central

Feulner, Markus; Hagen, Gunter; Hottner, Kathrin; Redel, Sabrina; Müller, Andreas; Moos, Ralf

2017-01-01

Due to increasingly tighter emission limits for diesel and gasoline engines, especially concerning particulate matter emissions, particulate filters are becoming indispensable devices for exhaust gas after treatment. Thereby, for an efficient engine and filter control strategy and a cost-efficient filter design, reliable technologies to determine the soot load of the filters and to measure particulate matter concentrations in the exhaust gas during vehicle operation are highly needed. In this study, different approaches for soot sensing are compared. Measurements were conducted on a dynamometer diesel engine test bench with a diesel particulate filter (DPF). The DPF was monitored by a relatively new microwave-based approach. Simultaneously, a resistive type soot sensor and a Pegasor soot sensing device as a reference system measured the soot concentration exhaust upstream of the DPF. By changing engine parameters, different engine out soot emission rates were set. It was found that the microwave-based signal may not only indicate directly the filter loading, but by a time derivative, the engine out soot emission rate can be deduced. Furthermore, by integrating the measured particulate mass in the exhaust, the soot load of the filter can be determined. In summary, all systems coincide well within certain boundaries and the filter itself can act as a soot sensor. PMID:28218700

HOT CELL BUILDING, TRA632. FIRST FLOOR FOUNDATION PLAN SHOWS SECTIONALIZED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HOT CELL BUILDING, TRA-632. FIRST FLOOR FOUNDATION PLAN SHOWS SECTIONALIZED FLOOR LOADINGS AND CONCRETE SLAB THICKNESSES, A TYPICAL FEATURE OF NUCLEAR ARCHITECTURE. IDAHO OPERATIONS OFFICE MTR-632-IDO-2, 11/1952. INL INDEX NO. 531-0632-62-396-110561, REV. 1. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Performance of a diesel engine operating on raw coal-diesel fuel and solvent refined coal-diesel fuel slurries. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, H.P.

1980-03-01

Performance tests using an 11 kW single cylinder diesel engine were made to determine the effects of three different micronized coal-fuel oil slurries being considered as alternative fuels. Slurries containing 20, 32, and 40%-wt micronized raw coal in No. 2 fuel oil were used. Results are presented indicating the changes in the concentrations of SO/sub X/ and NO/sub X/ in the exhaust, exhaust opacity, power and efficiency, and in wear rates relative to operation on fuel oil No. 2. The engine was operated for 10 h at full load and 1400 rpm on al fuels except the 40%-wt slurry. Thismore » test was discontinued because of extremely poor performance.« less

Performance of a diesel engine operating on raw coal-diesel fuel and solvent refined coal-diesel fuel slurries. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, H.P.

1980-03-01

Performance tests using an 11 kw single cylinder diesel engine were made to determine the effects of three different micronized coal-fuel oil slurries being considered as alternative fuels. Slurries containing 20, 32, and 40 percent by weight micronized raw coal in No. 2 fuel oil were used. Results are presented indicating the changes in the concentrations of SO/sub X/ and NO/sub X/ in the exhaust, exhaust opacity, power and efficiency, and in wear rates relative to operation on fuel oil No. 2. The engine was operated for 10 hrs at full load and 1400 rpm on all fuels except themore » 40% by weight slurry. This test was discontinued because of extremely poor performance.« less

Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

NASA Technical Reports Server (NTRS)

Macks, E Fred; Nemeth, Zolton N

1952-01-01

A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made by means of a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and the outer-race bearing operating temperatures are computed for the laboratory test rig and the turbojet engine. A method is given that enables the designer to predict the inner- and outer-race turbine roller-bearing temperatures from single curves, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter, or any combination of these parameters.

14 CFR 23.1193 - Cowling and nacelle.

Code of Federal Regulations, 2013 CFR

2013-01-01

... resist any vibration, inertia, and air loads to which it may be subjected in operation. (b) There must be... multiengine airplane with supercharged engines must be designed and constructed so that with the landing gear...

14 CFR 23.1193 - Cowling and nacelle.

Code of Federal Regulations, 2010 CFR

2010-01-01

... resist any vibration, inertia, and air loads to which it may be subjected in operation. (b) There must be... multiengine airplane with supercharged engines must be designed and constructed so that with the landing gear...

14 CFR 23.1193 - Cowling and nacelle.

Code of Federal Regulations, 2011 CFR

2011-01-01

... resist any vibration, inertia, and air loads to which it may be subjected in operation. (b) There must be... multiengine airplane with supercharged engines must be designed and constructed so that with the landing gear...

14 CFR 23.1193 - Cowling and nacelle.

Code of Federal Regulations, 2014 CFR

2014-01-01

... resist any vibration, inertia, and air loads to which it may be subjected in operation. (b) There must be... multiengine airplane with supercharged engines must be designed and constructed so that with the landing gear...

Investigation of the part-load performance of two 1.12 MW regenerative marine gas turbines

NASA Astrophysics Data System (ADS)

Korakianitis, T.; Beier, K. J.

1994-04-01

Regenerative and intercooled-regenerative gas turbine engines with low pressure ratio have significant efficiency advantages over traditional aero-derivative engines of higher pressure ratios, and can compete with modern diesel engines for marine propulsion. Their performance is extremely sensitive to thermodynamic-cycle parameter choices and the type of components. The performances of two 1.12 MW (1500 hp) regenerative gas turbines are predicted with computer simulations. One engine has a single-shaft configuration, and the other has a gas-generator/power-turbine combination. The latter arrangement is essential for wide off-design operating regime. The performance of each engine driving fixed-pitch and controllable-pitch propellers, or an AC electric bus (for electric-motor-driven propellers) is investigated. For commercial applications the controllable-pitch propeller may have efficiency advantages (depending on engine type and shaft arrangements). For military applications the electric drive provides better operational flexibility.

Torque sensor

NASA Astrophysics Data System (ADS)

Fgeppert, E.

1984-09-01

Mechanical means for sensing turning torque generated by the load forces in a rotary drive system is described. The sensing means is designed to operate with minimal effect on normal operation of the drive system. The invention can be employed in various drive systems, e.g., automotive engine-transmission power plants, electric motor-operated tools, and metal cutting machines. In such drive systems, the torque-sensing feature may be useful for actuation of various control devices, such as electric switches, mechanical clutches, brake actuators, fluid control valves, or audible alarms. The torque-sensing function can be used for safety overload relief, motor de-energization, engine fuel control transmission clutch actuation, remote alarm signal, tool breakage signal, etc.

49 CFR 174.112 - Loading Division 1.3 materials and Division 1.2 (explosive) materials (Also see § 174.101).

Code of Federal Regulations, 2012 CFR

2012-10-01

... materials and Division 1.2 (explosive) materials may not be loaded, transported or stored in a rail car equipped with any type of lighted heater or open-flame device, or in a rail car equipped with any apparatus or mechanism utilizing an internal combustion engine in its operation. (b) Except as provided in...

49 CFR 174.112 - Loading Division 1.3 materials and Division 1.2 (explosive) materials (Also see § 174.101).

Code of Federal Regulations, 2014 CFR

2014-10-01

... materials and Division 1.2 (explosive) materials may not be loaded, transported or stored in a rail car equipped with any type of lighted heater or open-flame device, or in a rail car equipped with any apparatus or mechanism utilizing an internal combustion engine in its operation. (b) Except as provided in...

49 CFR 174.112 - Loading Division 1.3 materials and Division 1.2 (explosive) materials (Also see § 174.101).

Code of Federal Regulations, 2013 CFR

2013-10-01

... materials and Division 1.2 (explosive) materials may not be loaded, transported or stored in a rail car equipped with any type of lighted heater or open-flame device, or in a rail car equipped with any apparatus or mechanism utilizing an internal combustion engine in its operation. (b) Except as provided in...

49 CFR 174.112 - Loading Division 1.3 materials and Division 1.2 (explosive) materials (Also see § 174.101).

Code of Federal Regulations, 2011 CFR

2011-10-01

... materials and Division 1.2 (explosive) materials may not be loaded, transported or stored in a rail car equipped with any type of lighted heater or open-flame device, or in a rail car equipped with any apparatus or mechanism utilizing an internal combustion engine in its operation. (b) Except as provided in...

49 CFR 174.112 - Loading Division 1.3 materials and Division 1.2 (explosive) materials (Also see § 174.101).

Code of Federal Regulations, 2010 CFR

2010-10-01

... materials and Division 1.2 (explosive) materials may not be loaded, transported or stored in a rail car equipped with any type of lighted heater or open-flame device, or in a rail car equipped with any apparatus or mechanism utilizing an internal combustion engine in its operation. (b) Except as provided in...

Increasing the reliability of labor of railroad engineers

NASA Technical Reports Server (NTRS)

Genes, V. S.; Madiyevskiy, Y. M.

1975-01-01

It has been shown that the group of problems related to temporary overloads still require serious development with respect to further automating the basic control operation - programmed selection of speed and braking. The problem of systems for warning the engineer about the condition of the unseen track segments remains a very serious one. Systems of hygenic support of the engineer also require constructive development. The problems of ensuring the reliability of work of engineers in periods of low information load, requiring motor acts, can basically be considered theoretically solved.

Cryogenic gear technology for an orbital transfer vehicle engine and tester design

NASA Technical Reports Server (NTRS)

Calandra, M.; Duncan, G.

1986-01-01

Technology available for gears used in advanced Orbital Transfer Vehicle rocket engines and the design of a cryogenic adapted tester used for evaluating advanced gears are presented. The only high-speed, unlubricated gears currently in cryogenic service are used in the RL10 rocket engine turbomachinery. Advanced rocket engine gear systems experience operational load conditions and rotational speed that are beyond current experience levels. The work under this task consisted of a technology assessment and requirements definition followed by design of a self-contained portable cryogenic adapted gear test rig system.

Dynamic Load Predictions for Launchers Using Extra-Large Eddy Simulations X-Les

NASA Astrophysics Data System (ADS)

Maseland, J. E. J.; Soemarwoto, B. I.; Kok, J. C.

2005-02-01

Flow-induced unsteady loads can have a strong impact on performance and flight characteristics of aerospace vehicles and therefore play a crucial role in their design and operation. Complementary to costly flight tests and delicate wind-tunnel experiments, unsteady loads can be calculated using time-accurate Computational Fluid Dynamics. A capability to accurately predict the dynamic loads on aerospace structures at flight Reynolds numbers can be of great value for the design and analysis of aerospace vehicles. Advanced space launchers are subject to dynamic loads in the base region during the ascent to space. In particular the engine and nozzle experience aerodynamic pressure fluctuations resulting from massive flow separations. Understanding these phenomena is essential for performance enhancements for future launchers which operate a larger nozzle. A new hybrid RANS-LES turbulence modelling approach termed eXtra-Large Eddy Simulations (X-LES) holds the promise to capture the flow structures associated with massive separations and enables the prediction of the broad-band spectrum of dynamic loads. This type of method has become a focal point, reducing the cost of full LES, driven by the demand for their applicability in an industrial environment. The industrial feasibility of X-LES simulations is demonstrated by computing the unsteady aerodynamic loads on the main-engine nozzle of a generic space launcher configuration. The potential to calculate the dynamic loads is qualitatively assessed for transonic flow conditions in a comparison to wind-tunnel experiments. In terms of turn-around-times, X-LES computations are already feasible within the time-frames of the development process to support the structural design. Key words: massive separated flows; buffet loads; nozzle vibrations; space launchers; time-accurate CFD; composite RANS-LES formulation.

Stratified charge rotary aircraft engine technology enablement program

NASA Technical Reports Server (NTRS)

Badgley, P. R.; Irion, C. E.; Myers, D. M.

1985-01-01

The multifuel stratified charge rotary engine is discussed. A single rotor, 0.7L/40 cu in displacement, research rig engine was tested. The research rig engine was designed for operation at high speeds and pressures, combustion chamber peak pressure providing margin for speed and load excursions above the design requirement for a high is advanced aircraft engine. It is indicated that the single rotor research rig engine is capable of meeting the established design requirements of 120 kW, 8,000 RPM, 1,379 KPA BMEP. The research rig engine, when fully developed, will be a valuable tool for investigating, advanced and highly advanced technology components, and provide an understanding of the stratified charge rotary engine combustion process.

Study of advanced radial outflow turbine for solar steam Rankine engines

NASA Technical Reports Server (NTRS)

Martin, C.; Kolenc, T.

1979-01-01

The performance characteristics of various steam Rankine engine configurations for solar electric power generation were investigated. A radial outflow steam turbine was investigated to determine: (1) a method for predicting performance from experimental data; (2) the flexibility of a single design with regard to power output and pressure ratio; and (3) the effect of varying the number of turbine stages. All turbine designs were restricted to be compatible with commercially available gearboxes and generators. A study of several operating methods and control schemes for the steam Rankine engine shows that from an efficiency and control simplicity standpoint, the best approach is to hold turbine inlet temperature constant, vary turbine inlet pressure to match load, and allow condenser temperature to float maintaining constant heat rejection load.

Multimode power processor

DOEpatents

O'Sullivan, G.A.; O'Sullivan, J.A.

1999-07-27

In one embodiment, a power processor which operates in three modes: an inverter mode wherein power is delivered from a battery to an AC power grid or load; a battery charger mode wherein the battery is charged by a generator; and a parallel mode wherein the generator supplies power to the AC power grid or load in parallel with the battery. In the parallel mode, the system adapts to arbitrary non-linear loads. The power processor may operate on a per-phase basis wherein the load may be synthetically transferred from one phase to another by way of a bumpless transfer which causes no interruption of power to the load when transferring energy sources. Voltage transients and frequency transients delivered to the load when switching between the generator and battery sources are minimized, thereby providing an uninterruptible power supply. The power processor may be used as part of a hybrid electrical power source system which may contain, in one embodiment, a photovoltaic array, diesel engine, and battery power sources. 31 figs.

Multimode power processor

DOEpatents

O'Sullivan, George A.; O'Sullivan, Joseph A.

1999-01-01

In one embodiment, a power processor which operates in three modes: an inverter mode wherein power is delivered from a battery to an AC power grid or load; a battery charger mode wherein the battery is charged by a generator; and a parallel mode wherein the generator supplies power to the AC power grid or load in parallel with the battery. In the parallel mode, the system adapts to arbitrary non-linear loads. The power processor may operate on a per-phase basis wherein the load may be synthetically transferred from one phase to another by way of a bumpless transfer which causes no interruption of power to the load when transferring energy sources. Voltage transients and frequency transients delivered to the load when switching between the generator and battery sources are minimized, thereby providing an uninterruptible power supply. The power processor may be used as part of a hybrid electrical power source system which may contain, in one embodiment, a photovoltaic array, diesel engine, and battery power sources.

Sweep-twist adaptive rotor blade : final project report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashwill, Thomas D.

2010-02-01

Knight & Carver was contracted by Sandia National Laboratories to develop a Sweep Twist Adaptive Rotor (STAR) blade that reduced operating loads, thereby allowing a larger, more productive rotor. The blade design used outer blade sweep to create twist coupling without angled fiber. Knight & Carver successfully designed, fabricated, tested and evaluated STAR prototype blades. Through laboratory and field tests, Knight & Carver showed the STAR blade met the engineering design criteria and economic goals for the program. A STAR prototype was successfully tested in Tehachapi during 2008 and a large data set was collected to support engineering and commercialmore » development of the technology. This report documents the methodology used to develop the STAR blade design and reviews the approach used for laboratory and field testing. The effort demonstrated that STAR technology can provide significantly greater energy capture without higher operating loads on the turbine.« less

CrossTalk: The Journal of Defense Software Engineering. Volume 20, Number 9, September 2007

DTIC Science & Technology

2007-09-01

underlying application framework, e.g., Java Enter- prise Edition or .NET. This increases the risk that consumer Web services not based on the same...weaknesses and vulnera- bilities that are targeted by attackers and malicious code. For example, Apache Axis 2 enables a Java devel- oper to simply...load his/her Java objects into the Axis SOAP engine. At runtime, it is the SOAP engine that determines which incoming SOAP request messages should be

Research of some operating parameters and the emissions level variation in a spark ignited engine through on-board investigation methods in different loading conditions

NASA Astrophysics Data System (ADS)

Iosif, Ferenti; Baldean, Doru Laurean

2014-06-01

The present paper shows research made on a spark ignited engine with port fuel injection in different operation conditions in order to improve the comprehension about the cold start sequence, acceleration when changing the gear ratios, quality of combustion process and also any measures to be taken for pollutant reduction in such cases. The engineering endeavor encompasses the pollutants investigation during the operation time of gasoline supplied engine with four inline cylinders in different conditions. The temperature and any other parameters were measured with specific sensors installed on the engine or in the exhaust pipes. All the data collected has been evaluated using electronic investigation systems and highly developed equipment. In this manner it has enabled the outline of the idea of how pollutants of engine vary in different operating conditions. Air quality in the everyday environment is very important for the human health, and thus the ambient air quality has a well-known importance in the European pollution standards and legislation. The high level of attention directed to the pollution problem in the European lifestyle is a driving force for all kinds of studies in the field of the reduction of engine emission.

Effects of diesel exhaust aftertreatment devices on concentrations and size distribution of aerosols in underground mine air.

PubMed

Bugarski, Aleksandar D; Schnakenberg, George H; Hummer, Ion A; Cauda, Emanuele; Janisko, Samuel I; Patts, Larry D

2009-09-01

Three types of uncatalyzed diesel particulate filter (DPF) systems, three types of high-temperature disposable filter elements (DFEs), and one diesel oxidation catalytic converter (DOC) were evaluated in underground mine conditions for their effects on the concentrations and size distributions of diesel aerosols. Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. The DPF systems reduced total mass of aerosols in the mine air approximately 10-fold for light-load and 20-fold or more for high-load test conditions. The DFEs offered similar reductions in aerosol mass concentrations. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the filter element The effectiveness of DPFs and DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. The effects of the DOC on mass and number concentrations of aerosols in mine air were relatively minor when compared to those of the DPF and DFE systems.

Experimental investigation on emission reduction in neem oil biodiesel using selective catalytic reduction and catalytic converter techniques.

PubMed

Viswanathan, Karthickeyan

2018-05-01

In the present study, non-edible seed oil namely raw neem oil was converted into biodiesel using transesterification process. In the experimentation, two biodiesel blends were prepared namely B25 (25% neem oil methyl ester with 75% of diesel) and B50 (50% neem oil methyl ester with 50% diesel). Urea-based selective catalytic reduction (SCR) technique with catalytic converter (CC) was fixed in the exhaust tail pipe of the engine for the reduction of engine exhaust emissions. Initially, the engine was operated with diesel as a working fluid and followed by refilling of biodiesel blends B25 and B50 to obtain the baseline readings without SCR and CC. Then, the same procedure was repeated with SCR and CC technique for emission reduction measurement in diesel, B25 and B50 sample. The experimental results revealed that the B25 blend showed higher break thermal efficiency (BTE) and exhaust gas temperature (EGT) with lower break-specific fuel consumption (BSFC) than B50 blend at all loads. On comparing with biodiesel blends, diesel experiences increased BTE of 31.9% with reduced BSFC of 0.29 kg/kWh at full load. A notable emission reduction was noticed for all test fuels in SCR and CC setup. At full load, B25 showed lower carbon monoxide (CO) of 0.09% volume, hydrocarbon (HC) of 24 ppm, and smoke of 14 HSU and oxides of nitrogen (NOx) of 735 ppm than diesel and B50 in SCR and CC setup. On the whole, the engine with SCR and CC setup showed better performance and emission characteristics than standard engine operation.

Micro-engineered first wall tungsten armor for high average power laser fusion energy systems

NASA Astrophysics Data System (ADS)

Sharafat, Shahram; Ghoniem, Nasr M.; Anderson, Michael; Williams, Brian; Blanchard, Jake; Snead, Lance; HAPL Team

2005-12-01

The high average power laser program is developing an inertial fusion energy demonstration power reactor with a solid first wall chamber. The first wall (FW) will be subject to high energy density radiation and high doses of high energy helium implantation. Tungsten has been identified as the candidate material for a FW armor. The fundamental concern is long term thermo-mechanical survivability of the armor against the effects of high temperature pulsed operation and exfoliation due to the retention of implanted helium. Even if a solid tungsten armor coating would survive the high temperature cyclic operation with minimal failure, the high helium implantation and retention would result in unacceptable material loss rates. Micro-engineered materials, such as castellated structures, plasma sprayed nano-porous coatings and refractory foams are suggested as a first wall armor material to address these fundamental concerns. A micro-engineered FW armor would have to be designed with specific geometric features that tolerate high cyclic heating loads and recycle most of the implanted helium without any significant failure. Micro-engineered materials are briefly reviewed. In particular, plasma-sprayed nano-porous tungsten and tungsten foams are assessed for their potential to accommodate inertial fusion specific loads. Tests show that nano-porous plasma spray coatings can be manufactured with high permeability to helium gas, while retaining relatively high thermal conductivities. Tungsten foams where shown to be able to overcome thermo-mechanical loads by cell rotation and deformation. Helium implantation tests have shown, that pulsed implantation and heating releases significant levels of implanted helium. Helium implantation and release from tungsten was modeled using an expanded kinetic rate theory, to include the effects of pulsed implantations and thermal cycles. Although, significant challenges remain micro-engineered materials are shown to constitute potential candidate FW armor materials.

Improving generalized inverted index lock wait times

NASA Astrophysics Data System (ADS)

Borodin, A.; Mirvoda, S.; Porshnev, S.; Ponomareva, O.

2018-01-01

Concurrent operations on tree like data structures is a cornerstone of any database system. Concurrent operations intended for improving read\\write performance and usually implemented via some way of locking. Deadlock-free methods of concurrency control are known as tree locking protocols. These protocols provide basic operations(verbs) and algorithm (ways of operation invocations) for applying it to any tree-like data structure. These algorithms operate on data, managed by storage engine which are very different among RDBMS implementations. In this paper, we discuss tree locking protocol implementation for General inverted index (Gin) applied to multiversion concurrency control (MVCC) storage engine inside PostgreSQL RDBMS. After that we introduce improvements to locking protocol and provide usage statistics about evaluation of our improvement in very high load environment in one of the world’s largest IT company.

Spit-Hole Effects on the Ballistics of a 7.62-mm Cartridge

DTIC Science & Technology

2014-02-01

barrel retains 0.50 in (12.7 mm) of rifling. The midchamber pressure transducer, Kistler Model 6215 (8), is consistent with previous experiments...Nemours and Company. 2 Kistler Model 9031A Load Washer (9). Force transducer selection was driven by the anticipated load and the necessity of an...Development and Engineering Center, Picatinny Arsenal, NJ, January 1986. 8. Kistler Operating Instructions, Quartz High-Pressure Sensor Type 6215

Fractional watt Vuillemier cryogenic refrigerator program engineering notebook. Volume 2: Stress analysis

NASA Technical Reports Server (NTRS)

Miller, W. S.

1974-01-01

A structural analysis performed on the 1/4-watt cryogenic refrigerator. The analysis covered the complete assembly except for the cooling jacket and mounting brackets. Maximum stresses, margin of safety, and natural frequencies were calculated for structurally loaded refrigerator components shown in assembly drawings. The stress analysis indicates that the design is satisfactory for the specified vibration environment, and the proof, burst, and normal operating loads.

Study of free-piston Stirling engine driven linear alternators

NASA Technical Reports Server (NTRS)

Nasar, S. A.; Chen, C.

1987-01-01

The analysis, design and operation of single phase, single slot tubular permanent magnet linear alternator is presented. Included is the no-load and on-load magnetic field investigation, permanent magnet's leakage field analysis, parameter identification, design guidelines and an optimal design of a permanent magnet linear alternator. For analysis of the magnetic field, a simplified magnetic circuit is utilized. The analysis accounts for saturation, leakage and armature reaction.

Wiseman on COLBERT in Node 3

NASA Image and Video Library

2014-05-31

ISS040-E-006091 (31 May 2014) --- NASA astronaut Reid Wiseman, Expedition 40 flight engineer, equipped with a bungee harness, exercises on the Combined Operational Load Bearing External Resistance Treadmill (COLBERT) in the Tranquility node of the International Space Station.

Monitoring of diesel engine combustions based on the acoustic source characterisation of the exhaust system

NASA Astrophysics Data System (ADS)

Jiang, J.; Gu, F.; Gennish, R.; Moore, D. J.; Harris, G.; Ball, A. D.

2008-08-01

Acoustic methods are among the most useful techniques for monitoring the condition of machines. However, the influence of background noise is a major issue in implementing this method. This paper introduces an effective monitoring approach to diesel engine combustion based on acoustic one-port source theory and exhaust acoustic measurements. It has been found that the strength, in terms of pressure, of the engine acoustic source is able to provide a more accurate representation of the engine combustion because it is obtained by minimising the reflection effects in the exhaust system. A multi-load acoustic method was then developed to determine the pressure signal when a four-cylinder diesel engine was tested with faults in the fuel injector and exhaust valve. From the experimental results, it is shown that a two-load acoustic method is sufficient to permit the detection and diagnosis of abnormalities in the pressure signal, caused by the faults. This then provides a novel and yet reliable method to achieve condition monitoring of diesel engines even if they operate in high noise environments such as standby power stations and vessel chambers.

Acoustic emission characteristics of a single cylinder diesel generator at various loads and with a failing injector

NASA Astrophysics Data System (ADS)

Dykas, Brian; Harris, James

2017-09-01

Acoustic emission sensing techniques have been applied in recent years to dynamic machinery with varying degrees of success in diagnosing various component faults and distinguishing between operating conditions. This work explores basic properties of acoustic emission signals measured on a small single cylinder diesel engine in a laboratory setting. As reported in other works in the open literature, the measured acoustic emission on the engine is mostly continuous mode and individual burst events are generally not readily identifiable. Therefore, the AE are processed into the local (instantaneous) root mean square (rms) value of the signal which is averaged over many cycles to obtain a mean rms AE in the crank angle domain. Crank-resolved spectral representation of the AE is also given but rigorous investigation of the AE spectral qualities is left to future study. Cycle-to-cycle statistical dispersion of the AE signal is considered to highlight highly variable engine processes. Engine speed was held constant but load conditions are varied to investigate AE signal sensitivity to operating condition. Furthermore, during the course of testing the fuel injector developed a fault and acoustic emission signals were captured and several signal attributes were successful in distinguishing this altered condition. The sampling and use of instantaneous rms acoustic emission signal demonstrated promise for non-intrusive and economical change detection of engine injection, combustion and valve events.

Performance Prediction and Simulation of Gas Turbine Engine Operation (La presision des performances et la simulation du fonctionnement des turbomoteurs)

DTIC Science & Technology

2002-04-01

configuration associated with the HSCT program was analyzed in terms of inlet unstart and the effect of the regurgitated shock wave. Inlet start is a...heavily loaded take off or dog -fight phases of flight. Less critical issues, such as thrust loss during supersonic operations, may also appear. From the

Intelligent Engine Systems: Alternate Fuels Evaluation

NASA Technical Reports Server (NTRS)

Ballal, Dilip

2008-01-01

The performance and gaseous emissions were measured for a well-stirred reactor operating under lean conditions for two fuels: JP8 and a synthetic Fisher-Tropsch fuel over a range of equivalence ratios from 0.6 down to the lean blowout. The lean blowout characteristics were determined in LBO experiments at loading parameter values from 0.7 to 1.4. The lean blowout characteristics were then explored under higher loading conditions by simulating higher altitude operation with the use of nitrogen as a dilution gas for the air stream. The experiments showed that: (1) The lean blowout characteristics for the two fuels were close under both low loading and high loading conditions. (2) The combustion temperatures and observed combustion efficiencies were similar for the two fuels. (3) The gaseous emissions were similar for the two fuels and the differences in the H2O and CO2 emissions appear to be directly relatable to the C/H ratio for the fuels.

Simulational nanoengineering: Molecular dynamics implementation of an atomistic Stirling engine.

PubMed

Rapaport, D C

2009-04-01

A nanoscale-sized Stirling engine with an atomistic working fluid has been modeled using molecular dynamics simulation. The design includes heat exchangers based on thermostats, pistons attached to a flywheel under load, and a regenerator. Key aspects of the behavior, including the time-dependent flows, are described. The model is shown to be capable of stable operation while producing net work at a moderate level of efficiency.

Thrust stand evaluation of engine performance improvement algorithms in an F-15 airplane

NASA Technical Reports Server (NTRS)

Conners, Timothy R.

1992-01-01

An investigation is underway to determine the benefits of a new propulsion system optimization algorithm in an F-15 airplane. The performance seeking control (PSC) algorithm optimizes the quasi-steady-state performance of an F100 derivative turbofan engine for several modes of operation. The PSC algorithm uses an onboard software engine model that calculates thrust, stall margin, and other unmeasured variables for use in the optimization. As part of the PSC test program, the F-15 aircraft was operated on a horizontal thrust stand. Thrust was measured with highly accurate load cells. The measured thrust was compared to onboard model estimates and to results from posttest performance programs. Thrust changes using the various PSC modes were recorded. Those results were compared to benefits using the less complex highly integrated digital electronic control (HIDEC) algorithm. The PSC maximum thrust mode increased intermediate power thrust by 10 percent. The PSC engine model did very well at estimating measured thrust and closely followed the transients during optimization. Quantitative results from the evaluation of the algorithms and performance calculation models are included with emphasis on measured thrust results. The report presents a description of the PSC system and a discussion of factors affecting the accuracy of the thrust stand load measurements.

Energy Engineering Analysis (EEA) program for Lone Star Army Ammunition Plant, Texas. Executive summary. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The objective of this Energy Engineering Analysis (EEA) for LSAAP is threefold: Develop a systematic plan of projects which will result in reducing energy consumption. Consider renewable energy sources with the objective of establishing an orderly procedure for reducing use of non-renewable energy sources. Determine the feasibility of Total Energy (TE), Selective Energy (SE), and Central Heating Plant (CHP) concepts using alternative fuels. In essence, an assessment of the entire energy picture at LSAAP was undertaken. This report is a summary of that effort. LSAAP was originally built during 1941 and 1942 as a shell loading plant for the Army.more » After World War II, the facility was deactivated until 1951 when it was reactivated as a Government Owned, Contractor Operated (GOCO) facility. Day and Zimmerman was selected as the operator in 1951 and has been the operating contractor ever since. Located just west of Texarkana, Texas, LSAAP encompasses an area of approximately 15,546 acres. The primary mission of LSAAP is to load, assemble and pack ammunition and ammunition components for the Army.« less

Wakata exercises on the COLBERT

NASA Image and Video Library

2013-11-15

ISS038-E-002210 (14 Nov. 2013) --- Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, equipped with a bungee harness, exercises on the Combined Operational Load Bearing External Resistance Treadmill (COLBERT) in the Tranquility node of the International Space Station.

Adaptive Development

NASA Technical Reports Server (NTRS)

2005-01-01

The goal of this research is to develop and demonstrate innovative adaptive seal technologies that can lead to dramatic improvements in engine performance, life, range, and emissions, and enhance operability for next generation gas turbine engines. This work is concentrated on the development of self-adaptive clearance control systems for gas turbine engines. Researchers have targeted the high-pressure turbine (HPT) blade tip seal location for following reasons: Current active clearance control (ACC) systems (e.g., thermal case-cooling schemes) cannot respond to blade tip clearance changes due to mechanical, thermal, and aerodynamic loads. As such they are prone to wear due to the required tight running clearances during operation. Blade tip seal wear (increased clearances) reduces engine efficiency, performance, and service life. Adaptive sealing technology research has inherent impact on all envisioned 21st century propulsion systems (e.g. distributed vectored, hybrid and electric drive propulsion concepts).

Measurements of NOx emissions and in-service duty cycle from a towboat operating on the inland river system.

PubMed

Corbett, J J; Robinson, A L

2001-04-01

This paper describes measurements of NOx emissions from one engine on a commercial towboat operating on the Upper Ohio River system around the Port of Pittsburgh. Continuous measurements were made over a one-week period to characterize emissions during normal operations. The average NOx emission factor is 70 +/- 4.2 kg of NOx per t of fuel, similar to that of larger marine engines. A vessel-specific duty cycle is derived to characterize the towboat's operations; more than 50% of the time the vessel engines are at idle. Although recently promulgated EPA regulations apply only to new marine engines, these data provide insight into inland-river operations, which can be used to evaluate these regulations within the inland river context. This vessel operates as a courier service, scheduling pickups and deliveries of single- or multiple-barge loads per customers' requests; as many as 30% of the 277 towboats in the Pittsburgh region operate in this fashion. The EPA-prescribed ISO E3 duty cycle does not accurately describe inland-river operations of this towboat: its application overestimates actual NOx emissions by 14%. Only 41% of this vessel's operations fall within the Not-To-Exceed Zone defined by the EPA regulations, which limits the effectiveness of this component of the regulations to limit emissions from vessels that operate in a similar fashion.

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

Impact of the injection dose of exhaust gases, on work parameters of combustion engine

NASA Astrophysics Data System (ADS)

Marek, W.; Śliwiński, K.

2016-09-01

This article is another one from the series in which were presented research results indicated the possible areas of application of the pneumatic injection using hot combustion gases proposed by Professor Jarnuszkiewicz. This publication present the results of the control system of exhaust gas recirculation. The main aim of this research was to determine the effect of exhaust gas recirculation to the operating parameters of the internal combustion engine on the basis of laboratory measurements. All measurements were performed at a constant engine speed. These conditions correspond to the operation of the motor operating an electrical generator. The study was conducted on the four-stroke two-cylinder engine with spark ignition. The study were specifically tested on the air injection system and therefore the selection of the rotational speed was not bound, as in conventional versions of operating parameters of the electrical machine. During the measurement there were applied criterion which used power control corresponding to the requirements of load power, at minimal values of engine speed. Recirculation value determined by the following recurrent position control valve of the injection doses inflator gas for pneumatic injection system. They were studied and recorded, the impact of dose of gases recirculation to the operating and ecological engine parameters such as power, torque, specific fuel consumption, efficiency, air fuel ratio, exhaust gas temperature and nitrogen oxides and hydrocarbons.

Treatment of munitions manufacturing airborne VOC`s by biofiltration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Severin, B.F.; Neilson, L.M.; Kim, B.J.

1997-12-31

The US Army Construction Engineering Research Laboratory contracted MBI International to perform a biofiltration study of industrial waste gas streams. Phase I of the study was a laboratory investigation of the treatability of a specific gas stream. The laboratory study was concluded in September, 1995. Phase II was the design, placement and operation of a full-scale biofilter. The project was completed in August, 1996. The specific gas stream originates from a munitions drying operation at the Olin Chemical Company, Lake City, AAP, Independence, MO. The production line is a blank bullet coating operation in the production line, slats of blankmore » ammunition are inverted and dipped into a coating material to seal the shell tips. The slats are then righted and moved into a drying box. The major solvent in the coating is ethyl acetate (70%) with about 30% of other solvent, such as, xylene and low molecular weight alcohols. The coating is thinned 50% with ethyl acetate, such that ethyl acetate represents more than 90% of the VOC load. The concentration of VOC`s is 400 ug/L at an air flow rate of 1000 ft{sup 3}/min. Laboratory results were collected on six test biofilter columns (15L). Steady state operations over a wide range of VOC loads were studied. The biofilters consistently destroyed 90-95% of the VOC`s. Square-wave dynamic loading cycles were studied to represent shift changes at the production facility. At high loadings, the biofilter performed well. At low organic loadings at applications of 5 hr/day of the gas stream, the filters required a small supplement of glucose to maintain column efficacy. A 1000 cubic foot bed volume, engineered media, biofilter was installed at Lake City AAP in January, 1996. The unit consists of a skid-mounted, class-1 division-1 explosion proof design including the blower package, biofilter media, nutrient addition, and automated VOC monitoring with PID. The unit was monitored for six months.« less

Start-up and control method and apparatus for resonant free piston Stirling engine

DOEpatents

Walsh, Michael M.

1984-01-01

A resonant free-piston Stirling engine having a new and improved start-up and control method and system. A displacer linear electrodynamic machine is provided having an armature secured to and movable with the displacer and having a stator supported by the Stirling engine housing in juxtaposition to the armature. A control excitation circuit is provided for electrically exciting the displacer linear electrodynamic machine with electrical excitation signals having substantially the same frequency as the desired frequency of operation of the Stirling engine. The excitation control circuit is designed so that it selectively and controllably causes the displacer electrodynamic machine to function either as a generator load to extract power from the displacer or the control circuit selectively can be operated to cause the displacer electrodynamic machine to operate as an electric drive motor to apply additional input power to the displacer in addition to the thermodynamic power feedback to the displacer whereby the displacer linear electrodynamic machine also is used in the electric drive motor mode as a means for initially starting the resonant free-piston Stirling engine.

Calculation of the Thermal Loading of the Cylinder-Piston Group of the Automobile Engine

NASA Astrophysics Data System (ADS)

Barchenko, F. B.; Bakulin, V. N.

2017-05-01

We propose a mathematical model for calculating thermal loods of parts of the cylinder-piston group of the automobile engine operating under unstable conditions in its complete life cycle. Methods have been described for calculating the boundary conditions to determine the thermal state of the parts of the cylinder-piston group of such an engine with the use of theoretical formulas, empirical and semiempirical relations, and tabulated data. In modeling, we calculated the work of all systems of the engine (pumps, pipelines, heat exchangers) influencing directly or indirectly the thermal state of its cylinder-piston group. The nonstationary thermal state was calculated once in the operating cycle of the engine with the use of the cycle-averaged values of the local heat transfer coefficients and the resulting temperature of the medium. The personal computer counting time for one time step of a transport diesel engine of typical design with a number of units of the order of 500 was 5 s.

14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

Code of Federal Regulations, 2011 CFR

2011-01-01

... § 25.363 Side load on engine and auxiliary power unit mounts. (a) Each engine and auxiliary power unit... the side load on the engine and auxiliary power unit mount, at least equal to the maximum load factor... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Side load on engine and auxiliary power...

14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

Code of Federal Regulations, 2010 CFR

2010-01-01

... § 25.363 Side load on engine and auxiliary power unit mounts. (a) Each engine and auxiliary power unit... the side load on the engine and auxiliary power unit mount, at least equal to the maximum load factor... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Side load on engine and auxiliary power...

14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

Code of Federal Regulations, 2013 CFR

2013-01-01

... § 25.363 Side load on engine and auxiliary power unit mounts. (a) Each engine and auxiliary power unit... the side load on the engine and auxiliary power unit mount, at least equal to the maximum load factor... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Side load on engine and auxiliary power...

14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

Code of Federal Regulations, 2014 CFR

2014-01-01

... § 25.363 Side load on engine and auxiliary power unit mounts. (a) Each engine and auxiliary power unit... the side load on the engine and auxiliary power unit mount, at least equal to the maximum load factor... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Side load on engine and auxiliary power...

14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.

Code of Federal Regulations, 2012 CFR

2012-01-01

... § 25.363 Side load on engine and auxiliary power unit mounts. (a) Each engine and auxiliary power unit... the side load on the engine and auxiliary power unit mount, at least equal to the maximum load factor... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Side load on engine and auxiliary power...

Cabin fuselage structural design with engine installation and control system

NASA Technical Reports Server (NTRS)

Balakrishnan, Tanapaal; Bishop, Mike; Gumus, Ilker; Gussy, Joel; Triggs, Mike

1994-01-01

Design requirements for the cabin, cabin system, flight controls, engine installation, and wing-fuselage interface that provide adequate interior volume for occupant seating, cabin ingress and egress, and safety are presented. The fuselage structure must be sufficient to meet the loadings specified in the appropriate sections of Federal Aviation Regulation Part 23. The critical structure must provide a safe life of 10(exp 6) load cycles and 10,000 operational mission cycles. The cabin seating and controls must provide adjustment to account for various pilot physiques and to aid in maintenance and operation of the aircraft. Seats and doors shall not bind or lockup under normal operation. Cabin systems such as heating and ventilation, electrical, lighting, intercom, and avionics must be included in the design. The control system will consist of ailerons, elevator, and rudders. The system must provide required deflections with a combination of push rods, bell cranks, pulleys, and linkages. The system will be free from slack and provide smooth operation without binding. Environmental considerations include variations in temperature and atmospheric pressure, protection against sand, dust, rain, humidity, ice, snow, salt/fog atmosphere, wind and gusts, and shock and vibration. The following design goals were set to meet the requirements of the statement of work: safety, performance, manufacturing and cost. To prevent the engine from penetrating the passenger area in the event of a crash was the primary safety concern. Weight and the fuselage aerodynamics were the primary performance concerns. Commonality and ease of manufacturing were major considerations to reduce cost.

Demand charge reduction with digester gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-02-01

This paper examines a rather sophisticated treatment system in the city of Whitewater, Wisconsin. The power generated is used to trim utility peak power loads and demand charges. Power is derived from four Waukesha VHP 3600G engine generator sets with provisions for a fifth as growth requires. The engine is a Waukesha F3521GU spark ignited, six-cylinder gas engine with 9.375 in. x 8.50 bore and stroke driving a Kato 350 kW generator rated at 480/277 volts and 1200 rpm. Normal operation is to reduce the peak demand.

Development and test of a 100 kVA superconducting transformer operated at 77 K

NASA Astrophysics Data System (ADS)

Kummeth, P.; Schlosser, R.; Massek, P.; Schmidt, H.; Albrecht, C.; Breitfelder, D.; Neumüller, H.-W.

2000-05-01

High-temperature superconducting (HTS) transformers are very promising candidates for application in electrical power engineering. Their main advantages are reduced size, weight, better efficiency and reduced potential fire and environmental hazards. We have designed, constructed and tested a 100 kVA HTS power transformer operated at 77 K. The nominal primary and secondary currents (voltages) are 18 A (5.6 kV) and 92 A (1.1 kV), respectively. No-load tests, short-circuit tests and load tests proved repeatedly that the transformer has the rated capacity. HTS winding losses of 20.6 W and iron losses of 403 W were measured.

Fuel Composition Effects at Constant RON and MON in an HCCI Engine Operated with Negative Valve Overlap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunting, Bruce G; Farrell, John T

2006-01-01

The effects of fuel properties on gasoline HCCI operation have been investigated in a single cylinder, 500 cc, 11.3 CR port fuel injected research engine, operated at lambda=1 and equipped with hydraulic valve actuation. HCCI is promoted by early exhaust valve closing to retain hot exhaust in the cylinder, thereby increasing the cylinder gas temperature. Test fuels were formulated with pure components to have the same RON, MON, and octane sensitivity as an indolene reference fuel, but with a wide range of fuel composition differences. Experiments have been carried out to determine if fuel composition plays a role in HCCImore » combustion properties, independent of octane numbers. Fuel economy, emissions, and combustion parameters have been measured at several fixed speed/load conditions over a range of exhaust valve closing angles. When the data are compared at constant combustion phasing, fuel effects on emissions and other combustion properties are small. However, when compared at constant exhaust valve closing angle, fuel composition effects are more pronounced, specifically regarding ignition. Operability range differences are also related to fuel composition. An all-paraffinic (normal, iso, and cycloparaffins) fuel exhibited distinctly earlier combustion phasing, increased rate of cylinder pressure rise, and increased rate of maximum heat release compared to the indolene reference fuel. Conversely, olefin-containing fuels exhibited retarded combustion phasing. The fuels with the most advanced ignition showed a wider operating range in terms of engine speed and load, irrespective of exhaust closing angle. These ignition differences reflect contributions from both fuel and EGR kinetics, the effects of which are discussed. The fuel composition variables are somewhat inter-correlated, which makes the experimental separation their effects imprecise with this small set of fuels, though clear trends are evident. The overall effects of fuel composition on engine performance and emissions are small. However, the results suggest that the effects on combustion phasing and engine operability range may need to be considered in the practical implementation of HCCI for fuels with large compositional variations.« less

Comprehensive Characterization Of Ultrafine Particulate Emission From 2007 Diesel Engines: PM Size Distribution, Loading And Indidividual Particle Size And Composition.

NASA Astrophysics Data System (ADS)

Zelenyuk, A.; Cuadra-Rodriguez, L. A.; Imre, D.; Shimpi, S.; Warey, A.

2006-12-01

The strong absorption of solar radiation by black carbon (BC) impacts the atmospheric radiative balance in a complex and significant manner. One of the most important sources of BC is vehicular emissions, of which diesel represents a significant fraction. To address this issue the EPA has issues new stringent regulations that will be in effect in 2007, limiting the amount of particulate mass that can be emitted by diesel engines. The new engines are equipped with aftertreatments that reduce PM emissions to the point, where filter measurements are subject to significant artifacts and characterization by other techniques presents new challenges. We will present the results of the multidisciplinary study conducted at the Cummins Technical Center in which a suite of instruments was deployed to yield comprehensive, temporally resolved information on the diesel exhaust particle loadings and properties in real-time: Particle size distributions were measured by Engine Exhaust Particle Sizer (EEPS) and Scanning Mobility Particle Sizer (SMPS). Total particle diameter concentration was obtained using Electrical Aerosol Detector (EAD). Laser Induced Incandescence and photoacoustic techniques were used to monitor the PM soot content. Single Particle Laser Ablation Time-of- flight Mass Spectrometer (SPLAT) provided the aerodynamic diameter and chemical composition of individual diesel exhaust particles. Measurements were conducted on a number of heavy duty diesel engines operated under variety of operating conditions, including FTP transient cycles, ramped-modal cycles and steady states runs. We have also characterized PM emissions during diesel particulate filter regeneration cycles. We will present a comparison of PM characteristics observed during identical cycles, but with and without the use of aftertreatment. A total of approximately 100,000 individual particles were sized and their composition characterized by SPLAT. The aerodynamic size distributions of the characterized particles were between 50 and 300 nm, depending on engine operating conditions and particle composition. We will show that while the drastically reduced diesel PM emissions often render the PM filter measurements inadequate due to organic vapor artifacts SPLAT demonstrated its capability to provide real-time information on size and composition of individual diesel exhaust particles as function of engine operating conditions with better than 1 minute resolution.

Development of a Stiffness-Based Chemistry Load Balancing Scheme, and Optimization of Input/Output and Communication, to Enable Massively Parallel High-Fidelity Internal Combustion Engine Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kodavasal, Janardhan; Harms, Kevin; Srivastava, Priyesh

A closed-cycle gasoline compression ignition engine simulation near top dead center (TDC) was used to profile the performance of a parallel commercial engine computational fluid dynamics code, as it was scaled on up to 4096 cores of an IBM Blue Gene/Q supercomputer. The test case has 9 million cells near TDC, with a fixed mesh size of 0.15 mm, and was run on configurations ranging from 128 to 4096 cores. Profiling was done for a small duration of 0.11 crank angle degrees near TDC during ignition. Optimization of input/output performance resulted in a significant speedup in reading restart files, andmore » in an over 100-times speedup in writing restart files and files for post-processing. Improvements to communication resulted in a 1400-times speedup in the mesh load balancing operation during initialization, on 4096 cores. An improved, “stiffness-based” algorithm for load balancing chemical kinetics calculations was developed, which results in an over 3-times faster run-time near ignition on 4096 cores relative to the original load balancing scheme. With this improvement to load balancing, the code achieves over 78% scaling efficiency on 2048 cores, and over 65% scaling efficiency on 4096 cores, relative to 256 cores.« less

Feasibility study of solid oxide fuel cell engines integrated with sprinter gas turbines: Modeling, design and control

NASA Astrophysics Data System (ADS)

Jia, Zhenzhong; Sun, Jing; Dobbs, Herb; King, Joel

2015-02-01

Conventional recuperating solid oxide fuel cell (SOFC)/gas turbine (GT) system suffers from its poor dynamic capability and load following performance. To meet the fast, safe and efficient load following requirements for mobile applications, a sprinter SOFC/GT system concept is proposed in this paper. In the proposed system, an SOFC stack operating at fairly constant temperature provides the baseline power with high efficiency while the fast dynamic capability of the GT-generator is fully explored for fast dynamic load following. System design and control studies have been conducted by using an SOFC/GT system model consisting of experimentally-verified component models. In particular, through analysis of the steady-state simulation results, an SOFC operation strategy is proposed to maintain fairly constant SOFC power (less than 2% power variation) and temperature (less than 2 K temperature variation) over the entire load range. A system design procedure well-suited to the proposed system has also been developed to help determining component sizes and the reference steady-state operation line. In addition, control analysis has been studied for both steady-state and transient operations. Simulation results suggest that the proposed system holds the promise to achieve fast and safe transient operations by taking full advantage of the fast dynamics of the GT-generator.

Transient Side Load Analysis of Out-of-Round Film-Cooled Nozzle Extensions

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike

2012-01-01

There was interest in understanding the impact of out-of-round nozzle extension on the nozzle side load during transient startup operations. The out-of-round nozzle extension could be the result of asymmetric internal stresses, deformation induced by previous tests, and asymmetric loads induced by hardware attached to the nozzle. The objective of this study was therefore to computationally investigate the effect of out-of-round nozzle extension on the nozzle side loads during an engine startup transient. The rocket engine studied encompasses a regeneratively cooled chamber and nozzle, along with a film cooled nozzle extension. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and transient inlet boundary flow properties derived from an engine system simulation. Six three-dimensional cases were performed with the out-of-roundness achieved by three different degrees of ovalization, elongated on lateral y and z axes: one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The results show that the separation line jump was the primary source of the peak side loads. Comparing to the peak side load of the perfectly round nozzle, the peak side loads increased for the slightly and more ovalized nozzle extensions, and either increased or decreased for the two significantly ovalized nozzle extensions. A theory based on the counteraction of the flow destabilizing effect of an exacerbated asymmetrical flow caused by a lower degree of ovalization, and the flow stabilizing effect of a more symmetrical flow, created also by ovalization, is presented to explain the observations obtained in this effort.

New Tools Being Developed for Engine- Airframe Blade-Out Structural Simulations

NASA Technical Reports Server (NTRS)

Lawrence, Charles

2003-01-01

One of the primary concerns of aircraft structure designers is the accurate simulation of the blade-out event. This is required for the aircraft to pass Federal Aviation Administration (FAA) certification and to ensure that the aircraft is safe for operation. Typically, the most severe blade-out occurs when a first-stage fan blade in a high-bypass gas turbine engine is released. Structural loading results from both the impact of the blade onto the containment ring and the subsequent instantaneous unbalance of the rotating components. Reliable simulations of blade-out are required to ensure structural integrity during flight as well as to guarantee successful blade-out certification testing. The loads generated by these analyses are critical to the design teams for several components of the airplane structures including the engine, nacelle, strut, and wing, as well as the aircraft fuselage. Currently, a collection of simulation tools is used for aircraft structural design. Detailed high-fidelity simulation tools are used to capture the structural loads resulting from blade loss, and then these loads are used as input into an overall system model that includes complete structural models of both the engines and the airframe. The detailed simulation (shown in the figure) includes the time-dependent trajectory of the lost blade and its interactions with the containment structure, and the system simulation includes the lost blade loadings and the interactions between the rotating turbomachinery and the remaining aircraft structural components. General-purpose finite element structural analysis codes are typically used, and special provisions are made to include transient effects from the blade loss and rotational effects resulting from the engine s turbomachinery. To develop and validate these new tools with test data, the NASA Glenn Research Center has teamed with GE Aircraft Engines, Pratt & Whitney, Boeing Commercial Aircraft, Rolls-Royce, and MSC.Software.

Fatigue Behavior and Deformation Mechanisms in Inconel 718 Superalloy Investigated

NASA Technical Reports Server (NTRS)

2005-01-01

The nickel-base superalloy Inconel 718 (IN 718) is used as a structural material for a variety of components in the space shuttle main engine (SSME) and accounts for more than half of the total weight of this engine. IN 718 is the bill-of-material for the pressure vessels of nickel-hydrogen batteries for the space station. In the case of the space shuttle main engine, structural components are typically subjected to startup and shutdown load transients and occasional overloads in addition to high-frequency vibratory loads from routine operation. The nickel-hydrogen battery cells are prooftested before service and are subjected to fluctuating pressure loads during operation. In both of these applications, the structural material is subjected to a monotonic load initially, which is subsequently followed by fatigue. To assess the life of these structural components, it is necessary to determine the influence of a prior monotonic load on the subsequent fatigue life of the superalloy. An insight into the underlying deformation and damage mechanisms is also required to properly account for the interaction between the prior monotonic load and the subsequent fatigue loading. An experimental investigation was conducted to establish the effect of prior monotonic straining on the subsequent fatigue behavior of wrought, double-aged, IN 718 at room temperature. First, monotonic strain tests and fully-reversed, strain-controlled fatigue tests were conducted on uniform-gage-section IN 718 specimens. Next, fully reversed fatigue tests were conducted under strain control on specimens that were monotonically strained in tension. Results from this investigation indicated that prior monotonic straining reduced the fatigue resistance of the superalloy particularly at the lowest strain range. Some of the tested specimens were sectioned and examined by transmission electron microscopy to reveal typical microstructures as well as the active deformation and damage mechanisms under each of the loading conditions. In monotonically strained specimens, deformation during the subsequent fatigue loading was mainly confined to the deformation bands initiated during the prior monotonic straining. This can cause dislocations to move more readily along the previously activated deformation bands and to pile up near grain boundaries, eventually making the grain boundaries susceptible to fatigue crack initiation. The mechanisms inferred from the microstructural investigation were extremely valuable in interpreting the influence of prior monotonic straining on the subsequent fatigue life of Inconel 718 superalloy.

Continuous bind-and-elute protein A capture chromatography: Optimization under process scale column constraints and comparison to batch operation.

PubMed

Kaltenbrunner, Oliver; Diaz, Luis; Hu, Xiaochun; Shearer, Michael

2016-07-08

Recently, continuous downstream processing has become a topic of discussion and analysis at conferences while no industrial applications of continuous downstream processing for biopharmaceutical manufacturing have been reported. There is significant potential to increase the productivity of a Protein A capture step by converting the operation to simulated moving bed (SMB) mode. In this mode, shorter columns are operated at higher process flow and corresponding short residence times. The ability to significantly shorten the product residence time during loading without appreciable capacity loss can dramatically increase productivity of the capture step and consequently reduce the amount of Protein A resin required in the process. Previous studies have not considered the physical limitations of how short columns can be packed and the flow rate limitations due to pressure drop of stacked columns. In this study, we are evaluating the process behavior of a continuous Protein A capture column cycling operation under the known pressure drop constraints of a compressible media. The results are compared to the same resin operated under traditional batch operating conditions. We analyze the optimum system design point for a range of feed concentrations, bed heights, and load residence times and determine achievable productivity for any feed concentration and any column bed height. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:938-948, 2016. © 2016 American Institute of Chemical Engineers.

Aerodynamic Heat-Power Engine Operating on a Closed Cycle

NASA Technical Reports Server (NTRS)

Ackeret, J.; Keller, D. C.

1942-01-01

Hot-air engines with dynamic compressors and turbines offer new prospects of success through utilization of units of high efficiencies and through the employment of modern materials of great strength at high temperature. Particular consideration is given to an aerodynamic prime mover operating on a closed circuit and heated externally. Increase of the pressure level of the circulating air permits a great increase of limit load of the unit. This also affords a possibility of regulation for which the internal efficiency of the unit changes but slightly. The effect of pressure and temperature losses is investigated. A general discussion is given of the experimental installation operating at the Escher Wyss plant in Zurich for a considerable time at high temperatures.

Evaluation of shuttle turbopump bearings

NASA Technical Reports Server (NTRS)

Dufrane, K. F.; Kannel, J. W.

1978-01-01

Because the high pressure turbopumps used on the space shuttle main engine (SSME) are high speed machines and rotor dynamics analysis of these units is very complicated, it was considered necessary to verify calculated turbomachinery shaft bearing loads by analysis of ball bearing load tracks. This report presents the methods used and the results of load track analysis on one set of bearings removed from a high pressure liquid oxygen turbopump which had been subjected to SSME static firing tests. This type of analysis was found useful in determining bearing operating conditions and for verifying rotor dynamics computer models.

Thermal-structural design study of an airframe-integrated Scramjet

NASA Technical Reports Server (NTRS)

Killackey, J. J.; Katinsky, E. A.; Tepper, S.; Vuigner, A. A.

1978-01-01

Design concepts are developed and evaluated for a cooled structures assembly for the Scramjet engine, for engine subsystems mass, volume, and operating requirements, and for the aircraft/engine interface. A thermal protection system was defined that makes it possible to attain a life of 100 hours and 1000 cycles. The coolant equivalence ratio at the Mach 10 maximum thermal loading condition is 0.6, indicating a capacity for airframe cooling. The mechanical design is feasible for manufacture using conventional materials. For the cooled structures in a six-module engine, the mass per unit capture area is 12.4 KN/sq m. The total weight of a six-module engine assembly including the fuel system is 14.73 KN.

Mariner Venus/Mercury 1973 rocket engine assembly

NASA Technical Reports Server (NTRS)

Snoke, D. R.; Williams, R. S.

1972-01-01

The fabrication and test of rocket engine assemblies (REA) for Mariner Venus/Mercury 1973 are reported. The fabrication, assembly and flight acceptance test of seven REA's including the type approval test of one engine and fabrication of one additional kit consisting of detail parts for an engine ready for catalyst loading are presented. The MV/M '73 REA which is a nominal 51 lbs thrust monopropellant engine is described. Under steady state operation the specific impulse is not less than 228 lb-sec at 55 lb and 218.5 lb-sec at 10 lb thrust varying linearly between these limits. The characteristic velocity is not less than 4100 ft/sec at any thrust level.

High Resolution Visualization Applied to Future Heavy Airlift Concept Development and Evaluation

NASA Technical Reports Server (NTRS)

FordCook, A. B.; King, T.

2012-01-01

This paper explores the use of high resolution 3D visualization tools for exploring the feasibility and advantages of future military cargo airlift concepts and evaluating compatibility with existing and future payload requirements. Realistic 3D graphic representations of future airlifters are immersed in rich, supporting environments to demonstrate concepts of operations to key personnel for evaluation, feedback, and development of critical joint support. Accurate concept visualizations are reviewed by commanders, platform developers, loadmasters, soldiers, scientists, engineers, and key principal decision makers at various stages of development. The insight gained through the review of these physically and operationally realistic visualizations is essential to refining design concepts to meet competing requirements in a fiscally conservative defense finance environment. In addition, highly accurate 3D geometric models of existing and evolving large military vehicles are loaded into existing and proposed aircraft cargo bays. In this virtual aircraft test-loading environment, materiel developers, engineers, managers, and soldiers can realistically evaluate the compatibility of current and next-generation airlifters with proposed cargo.

Mystery of Foil Air Bearings for Oil-free Turbomachinery Unlocked: Load Capacity Rule-of-thumb Allows Simple Estimation of Performance

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Valco, Mark J.

2002-01-01

The Oil-Free Turbomachinery team at the NASA Glenn Research Center has unlocked one of the mysteries surrounding foil air bearing performance. Foil air bearings are self-acting hydrodynamic bearings that use ambient air, or any fluid, as their lubricant. In operation, the motion of the shaft's surface drags fluid into the bearing by viscous action, creating a pressurized lubricant film. This lubricating film separates the stationary foil bearing surface from the moving shaft and supports load. Foil bearings have been around for decades and are widely employed in the air cycle machines used for cabin pressurization and cooling aboard commercial jetliners. The Oil-Free Turbomachinery team is fostering the maturation of this technology for integration into advanced Oil-Free aircraft engines. Elimination of the engine oil system can significantly reduce weight and cost and could enable revolutionary new engine designs. Foil bearings, however, have complex elastic support structures (spring packs) that make the prediction of bearing performance, such as load capacity, difficult if not impossible. Researchers at Glenn recently found a link between foil bearing design and load capacity performance. The results have led to a simple rule-of-thumb that relates a bearing's size, speed, and design to its load capacity. Early simple designs (Generation I) had simple elastic (spring) support elements, and performance was limited. More advanced bearings (Generation III) with elastic supports, in which the stiffness is varied locally to optimize gas film pressures, exhibit load capacities that are more than double those of the best previous designs. This is shown graphically in the figure. These more advanced bearings have enabled industry to introduce commercial Oil-Free gas-turbine-based electrical generators and are allowing the aeropropulsion industry to incorporate the technology into aircraft engines. The rule-of-thumb enables engine and bearing designers to easily size and select bearing technology for a new application and determine the level of complexity required in the bearings. This new understanding enables industry to assess the feasibility of new engine designs and provides critical guidance toward the future development of Oil-Free turbomachinery propulsion systems.

Tradeoff between magnet volume and tuning capacitor in a free piston Stirling engine power generation system

NASA Astrophysics Data System (ADS)

Fu, Z. X.; Nasar, S. A.; Rosswurm, Mark

This paper presents the criteria in selecting the size of the tuning capacitor, and the cost tradeoff between magnet volume and tuning capacitor in a free piston Stirling engine power generation system. The permissible range of capacitor size corresponding to different magnet volume, in order to prevent magnet demagnetization and stabilize the operation of the system, is determined. Within the permissible range suitable capacitor size may be selected to compensate the inductive load of the system to improve the overall power factor. If the capacitor size is not in the permissible range, there would exist a danger of losing magnet strength, or unstable operation of the engine that would destroy the engine due to unbounded amplitude of piston oscillations. The theory developed is then applied to a practical system, and the cost tradeoff between magnet volume and capacitor is studied.

Dynamometer Testing of Planar Mixed-Potential Sensors

DOE PAGES

Kreller, C. R.; Sekhar, P. K.; Prikhodko, V.; ...

2014-09-22

Mixed-potential sensors for vehicle on-board emissions monitoring applications have been fabricated in an automotive planar sensor configuration using high temperature ceramic co-fire methods. The sensing element consists of dense Pt and LaSrCrO electrodes and a porous 3 mol% YSZ electrolyte. This sensor construct exhibits preferential selectivity to NO x (NO+NO 2) when operated at a positive current bias. The performance of the planar sensors under engine-out conditions was recently evaluated at the Oak Ridge National Laboratory National Transportation Research Center on a GM 1.9L CIDI diesel engine. The sensor response qualitatively tracked transients in NO x measured via FTIR undermore » transient engine operation. Additionally, quantitative correlation between sensor voltage response and total NO x concentration was obtained under steady-state engine speed and load while varying exhaust gas recirculation (EGR) levels.« less

Testing of a variable-stroke Stirling engine

NASA Technical Reports Server (NTRS)

Thieme, Lanny G.; Allen, David J.

1986-01-01

Testing of a variable-stroke Stirling engine at NASA Lewis has been completed. In support of the DOE Stirling Engine Highway Vehicle Systems Program, the engine was tested for about 70 hours total with both He and H2 as working fluids over a range of pressures and strokes. A direct comparison was made of part-load efficiencies obtained with variable-stroke (VS) and variable-pressure operation. Two failures with the variable-angle swash-plate drive system limited testing to low power levels. These failures are not thought to be caused by problems inherent with the VS concept but do emphasize the need for careful design in the area of the crossheads.

Testing of a variable-stroke Stirling engine

NASA Technical Reports Server (NTRS)

Thieme, L. G.; Allen, D. J.

1986-01-01

Testing of a variable-stroke Stirling engine at NASA Lewis has been completed. In support of the DOE Stirling Engine Highway Vehicle Systems Program, the engine was tested for about 70 hours total with both He and H2 working fluids over a range of pressures and strokes. A direct comparison was made of part-load efficiencies obtained with variable-stroke (VS) and variable-pressure operation. Two failures with the variable-angle swash-plate drive system limited testing to low power levels. These failures are not thought to be caused by problems inherent with the VS concept but do emphasize the need for careful design in the area of the crossheads.

Miniaturization as a key factor to the development and application of advanced metrology systems

NASA Astrophysics Data System (ADS)

Furlong, Cosme; Dobrev, Ivo; Harrington, Ellery; Hefti, Peter; Khaleghi, Morteza

2012-10-01

Recent technological advances of miniaturization engineering are enabling the realization of components and systems with unprecedented capabilities. Such capabilities, which are significantly beneficial to scientific and engineering applications, are impacting the development and the application of optical metrology systems for investigations under complex boundary, loading, and operating conditions. In this paper, and overview of metrology systems that we are developing is presented. Systems are being developed and applied to high-speed and high-resolution measurements of shape and deformations under actual operating conditions for such applications as sustainability, health, medical diagnosis, security, and urban infrastructure. Systems take advantage of recent developments in light sources and modulators, detectors, microelectromechanical (MEMS) sensors and actuators, kinematic positioners, rapid prototyping fabrication technologies, as well as software engineering.

An Assessment of Gas Foil Bearing Scalability and the Potential Benefits to Civilian Turbofan Engines

NASA Technical Reports Server (NTRS)

Bruckner, Robert J.

2010-01-01

Over the past several years the term oil-free turbomachinery has been used to describe a rotor support system for high speed turbomachinery that does not require oil for lubrication, damping, or cooling. The foundation technology for oil-free turbomachinery is the compliant foil bearing. This technology can replace the conventional rolling element bearings found in current engines. Two major benefits are realized with this technology. The primary benefit is the elimination of the oil lubrication system, accessory gearbox, tower shaft, and one turbine frame. These components account for 8 to 13 percent of the turbofan engine weight. The second benefit that compliant foil bearings offer to turbofan engines is the capability to operate at higher rotational speeds and shaft diameters. While traditional rolling element bearings have diminished life, reliability, and load capacity with increasing speeds, the foil bearing has a load capacity proportional to speed. The traditional applications for foil bearings have been in small, lightweight machines. However, recent advancements in the design and manufacturing of foil bearings have increased their potential size. An analysis, grounded in experimentally proven operation, is performed to assess the scalability of the modern foil bearing. This analysis was coupled to the requirements of civilian turbofan engines. The application of the foil bearing to larger, high bypass ratio engines nominally at the 120 kN (approx.25000 lb) thrust class has been examined. The application of this advanced technology to this system was found to reduce mission fuel burn by 3.05 percent.

Effects on fatigue life of gate valves due to higher torque switch settings during operability testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richins, W.D.; Snow, S.D.; Miller, G.K.

1995-12-01

Some motor operated valves now have higher torque switch settings due to regulatory requirements to ensure valve operability with appropriate margins at design basis conditions. Verifying operability with these settings imposes higher stem loads during periodic inservice testing. These higher test loads increase stresses in the various valve internal parts which may in turn increase the fatigue usage factors. This increased fatigue is judged to be a concern primarily in the valve disks, seats, yokes, stems, and stem nuts. Although the motor operators may also have significantly increased loading, they are being evaluated by the manufacturers and are beyond themore » scope of this study. Two gate valves representative of both relatively weak and strong valves commonly used in commercial nuclear applications were selected for fatigue analyses. Detailed dimensional and test data were available for both valves from previous studies at the Idaho National Engineering Laboratory. Finite element models were developed to estimate maximum stresses in the internal parts of the valves and to identity the critical areas within the valves where fatigue may be a concern. Loads were estimated using industry standard equations for calculating torque switch settings prior and subsequent to the testing requirements of USNRC Generic Letter 89--10. Test data were used to determine both; (1) the overshoot load between torque switch trip and final seating of the disk during valve closing and (2) the stem thrust required to open the valves. The ranges of peak stresses thus determined were then used to estimate the increase in the fatigue usage factors due to the higher stem thrust loads. The usages that would be accumulated by 100 base cycles plus one or eight test cycles per year over 40 and 60 years of operation were calculated.« less

Nonlinear dynamic simulation of single- and multi-spool core engines

NASA Technical Reports Server (NTRS)

Schobeiri, T.; Lippke, C.; Abouelkheir, M.

1993-01-01

In this paper a new computational method for accurate simulation of the nonlinear dynamic behavior of single- and multi-spool core engines, turbofan engines, and power generation gas turbine engines is presented. In order to perform the simulation, a modularly structured computer code has been developed which includes individual mathematical modules representing various engine components. The generic structure of the code enables the dynamic simulation of arbitrary engine configurations ranging from single-spool thrust generation to multi-spool thrust/power generation engines under adverse dynamic operating conditions. For precise simulation of turbine and compressor components, row-by-row calculation procedures were implemented that account for the specific turbine and compressor cascade and blade geometry and characteristics. The dynamic behavior of the subject engine is calculated by solving a number of systems of partial differential equations, which describe the unsteady behavior of the individual components. In order to ensure the capability, accuracy, robustness, and reliability of the code, comprehensive critical performance assessment and validation tests were performed. As representatives, three different transient cases with single- and multi-spool thrust and power generation engines were simulated. The transient cases range from operating with a prescribed fuel schedule, to extreme load changes, to generator and turbine shut down.

Preliminary Flight Tests of the N.A.C.A. Roots Type Aircraft Engine Supercharger

NASA Technical Reports Server (NTRS)

Gardiner, Arthur W; Reid, Elliott G

1928-01-01

An investigation of the suitability of the N.A.C.A. Roots type aircraft engine supercharger to flight-operating conditions, as determined the effects of the use of the supercharger upon engine operation and airplane performance, is described in this report. Attention was concentrated on the operation of the engine-supercharger unit and on the improvement of climbing ability; some information concerning high speeds at altitude was obtained. The supercharger was found to be satisfactory under flight-operating conditions. Although two failures occurred during the tests, the causes of both were minor and have been eliminated. Careful examination of the engines revealed no detrimental effects which could be attributed to supercharging. Marked improvements in climbing ability and high speeds at altitude were effected. It was also found that the load which could be carried to a given moderate or high altitude in a fixed time was considerably augmented. A slight sacrifice of low-altitude performance was necessitated, however, by the use of a fixed-pitch propeller. From a consideration of the very satisfactory flight performance of the Roots supercharger and of its inherent advantages, it is concluded that this type is particularly attractive for use in certain classes of commercial airplanes and in a number of military types.

Progress on Shape Memory Alloy Actuator Development for Active Clearance Control

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan; Melcher, Kevin; Noebe, Ronald

2006-01-01

Results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine has been conducted. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 in. Design results show that an actuator comprised of 10 wires 2 in. in length is adequate for control at critical engine operating points and still exhibit acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

Utility gas turbine combustor viewing system: Volume 1, Conceptual design and initial field testing: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morey, W.W.

1988-12-01

This report summarizes the development and field testing of a combustor viewing probe (CVP) as a flame diagnostic monitor for utility gas turbine engines. The prototype system is capable of providing a visual record of combustor flame images, recording flame spectral data, analyzing image and spectral data, and diagnosing certain engine malfunctions. The system should provide useful diagnostic information to utility plant operators, and reduce maintenance costs. The field tests demonstrated the ability of the CVP to monitor combustor flame condition and to relate changes in the engine operation with variations in the flame signature. Engine light off, run upmore » to full speed, the addition of load, and the effect of water injection for NO/sub x/ control could easily be identified on the video monitor. The viewing probe was also valuable in identifying hard startups and shutdowns, as well as transient effects that can seriously harm the engine. 11 refs.« less

Co-Optima Project E2.2.2: Accelerate Development of ACI/LTC Fuel Effects on RCCI Combustion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musculus, Mark P.

Many advanced combustion approaches have demonstrated potential for achieving diesel-like thermal efficiency but with much lower pollutant emissions of particulate matter (PM) and nitrogen oxides (NOx). RCCI is one advanced combustion concept, which makes use of in-cylinder blending of two fuels with differing reactivity for improved control of the combustion phasing and rate (Reitz et al., 2015). Previous research and development at ORNL has demonstrated successful implementation of RCCI on a light-duty multi-cylinder engine over a wide range of operating conditions (Curran et al., 2015). Several challenges were encountered when extending the research to practical applications, including limits to themore » operating range, both for high and low loads. Co-optimizing the engine and fuel aspects of the RCCI approach might allow these operating limits to be overcome. The in-cylinder mechanisms by which fuel properties interact with engine operating condition variables is not well understood, however, in part because RCCI is a new combustion concept that is still being developed, and limited data have been acquired to date, especially using in-cylinder optical/imaging diagnostics. The objective of this work is to use in-cylinder diagnostics in a heavy-duty single-cylinder optical engine at SNL to understand the interplay between fuel properties and engine hardware and operating conditions for RCCI in general, and in particular for the light-duty multi-cylinder all-metal RCCI engine experiments at ORNL.« less

Materials and Manufacturing, Drafting 3: 9257.03.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

Designed for students interested in engineering fields pertaining to mechanical and electronic drafting, the course covers several types of drawings in the mechanical and electronic drafting field and many types of machine shop operations. The student will become familiar with stress, loading, safety factors, and manufacturing processes. The…

Design criteria monograph for high-load high-speed rolling-contact bearings

NASA Technical Reports Server (NTRS)

1972-01-01

Monograph was published which summarizes and systematically orders large body of successful techniques and practices developed for design of liquid rocket engine turbopump bearings. Document was written to organize and present significant experience and knowledge accumulated by NASA in development and operational programs.

Super Turbocharging the Direct Injection Diesel engine

NASA Astrophysics Data System (ADS)

Boretti, Albert

2018-03-01

The steady operation of a turbocharged diesel direct injection (TDI) engine featuring a variable speed ratio mechanism linking the turbocharger shaft to the crankshaft is modelled in the present study. Key parameters of the variable speed ratio mechanism are range of speed ratios, efficiency and inertia, in addition to the ability to control relative speed and flow of power. The device receives energy from, or delivers energy to, the crankshaft or the turbocharger. In addition to the pistons of the internal combustion engine (ICE), also the turbocharger thus contributes to the total mechanical power output of the engine. The energy supply from the crankshaft is mostly needed during sharp accelerations to avoid turbo-lag, and to boost torque at low speeds. At low speeds, the maximum torque is drastically improved, radically expanding the load range. Additionally, moving closer to the points of operation of a balanced turbocharger, it is also possible to improve both the efficiency η, defined as the ratio of the piston crankshaft power to the fuel flow power, and the total efficiency η*, defined as the ratio of piston crankshaft power augmented of the power from the turbocharger shaft to the fuel flow power, even if of a minimal extent. The energy supply to the crankshaft is possible mostly at high speeds and high loads, where otherwise the turbine could have been waste gated, and during decelerations. The use of the energy at the turbine otherwise waste gated translates in improvements of the total fuel conversion efficiency η* more than the efficiency η. Much smaller improvements are obtained for the maximum torque, yet again moving closer to the points of operation of a balanced turbocharger. Adopting a much larger turbocharger (target displacement x speed 30% larger than a conventional turbocharger), better torque outputs and fuel conversion efficiencies η* and η are possible at every speed vs. the engine with a smaller, balanced turbocharger. This result motivates further studies of the mechanism that may considerably benefit traditional powertrains based on diesel engines.

Modern high-strength steels for heavily loaded gearing (a review of engineering patents)

NASA Astrophysics Data System (ADS)

Voronenko, B. I.

1996-08-01

In order to increase the service life of machines the life of their parts should be increased. For example, in machine tool and lifting-and-transport manufacture the maintenance cost of the equipment over the duration of its operation often exceeds the cost of the new equipment by a factor of 10-20. This imposes strict requirements on structural materials for heavily loaded gearings, including the development of high-strength, wear-resistant, manufacture-adaptable, and economically alloyed steels.

Environmental and Mechanical Stability of Environmental Barrier Coated SA Tyrannohex SiC Composites Under Simulated Turbine Engine Environments

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Halbig, Michael Charles; Sing, Mrityunjay

2014-01-01

The environmental stability and thermal gradient cyclic durability performance of SA Tyrannohex composites were investigated for turbine engine component applications. The work has been focused on investigating the combustion rig recession, cyclic thermal stress resistance and thermomechanical low cycle fatigue of uncoated and environmental barrier coated Tyrannohex SiC SA composites in simulated turbine engine combustion water vapor, thermal gradients, and mechanical loading conditions. Flexural strength degradations have been evaluated, and the upper limits of operating temperature conditions for the SA composite material systems are discussed based on the experimental results.

Computer Review Can Cut HVAC Energy Use

ERIC Educational Resources Information Center

McClure, Charles J. R.

1974-01-01

A computerized review of construction bidding documents, usually done by a consulting engineer, can reveal how much money it will cost to operate various alternative types of HVAC equipment over a school's lifetime. The review should include a computerized load calculation, energy systems flow diagram, control system analysis, and a computerized…

Quantitative evolutionary design

PubMed Central

Diamond, Jared

2002-01-01

The field of quantitative evolutionary design uses evolutionary reasoning (in terms of natural selection and ultimate causation) to understand the magnitudes of biological reserve capacities, i.e. excesses of capacities over natural loads. Ratios of capacities to loads, defined as safety factors, fall in the range 1.2-10 for most engineered and biological components, even though engineered safety factors are specified intentionally by humans while biological safety factors arise through natural selection. Familiar examples of engineered safety factors include those of buildings, bridges and elevators (lifts), while biological examples include factors of bones and other structural elements, of enzymes and transporters, and of organ metabolic performances. Safety factors serve to minimize the overlap zone (resulting in performance failure) between the low tail of capacity distributions and the high tail of load distributions. Safety factors increase with coefficients of variation of load and capacity, with capacity deterioration with time, and with cost of failure, and decrease with costs of initial construction, maintenance, operation, and opportunity. Adaptive regulation of many biological systems involves capacity increases with increasing load; several quantitative examples suggest sublinear increases, such that safety factors decrease towards 1.0. Unsolved questions include safety factors of series systems, parallel or branched pathways, elements with multiple functions, enzyme reaction chains, and equilibrium enzymes. The modest sizes of safety factors imply the existence of costs that penalize excess capacities. Those costs are likely to involve wasted energy or space for large or expensive components, but opportunity costs of wasted space at the molecular level for minor components. PMID:12122135

Operational Weight Estimations of Commercial Jet Transport Aircraft

NASA Technical Reports Server (NTRS)

Anderson, Joseph L.

1972-01-01

In evaluating current or proposed commercial transport airplanes, there has not been available a ready means to determine weights so as to compare airplanes within this particular class. This paper describes the development of and presents such comparative tools. The major design characteristics of current American jet transport airplanes were collected, and these data were correlated by means of regression analysis to develop weight relationships for these airplanes as functions of their operational requirements. The characteristics for 23 airplanes were assembled and examined in terms of the effects of the number of people carried, the cargo load, and the operating range. These airplane characteristics were correlated for the airplanes as one of three subclasses, namely the small, twin-engine jet transport, the conventional three- and four-engine jets, and the new wide-body jets.

Quick look test report: MPT static firing no. 2 test MPT-S2

NASA Technical Reports Server (NTRS)

1978-01-01

The three engine cluster was fired at 70 percent power level for a nominal 15 seconds to evaluate the integrated performance of the main propulsion system. Engine ignition occurred at approximately 1403 with the planned mainstage duration achieved for all three engines. Operation of all systems was as expected with the exception of the recirculation pumps. The pumps were started while the propellant loading was in fast fill, but they cavitated and lost head at the termination of fast fill. The pumps were subsequently restarted after pressurizing the tank and draining back propellant to get good quality. Post test inspection of the engines revealed some discoloration on the inside of the thrust chamber and distorted drain lines for engine #2.

Artificial neural network (ANN)-based prediction of depth filter loading capacity for filter sizing.

PubMed

Agarwal, Harshit; Rathore, Anurag S; Hadpe, Sandeep Ramesh; Alva, Solomon J

2016-11-01

This article presents an application of artificial neural network (ANN) modelling towards prediction of depth filter loading capacity for clarification of a monoclonal antibody (mAb) product during commercial manufacturing. The effect of operating parameters on filter loading capacity was evaluated based on the analysis of change in the differential pressure (DP) as a function of time. The proposed ANN model uses inlet stream properties (feed turbidity, feed cell count, feed cell viability), flux, and time to predict the corresponding DP. The ANN contained a single output layer with ten neurons in hidden layer and employed a sigmoidal activation function. This network was trained with 174 training points, 37 validation points, and 37 test points. Further, a pressure cut-off of 1.1 bar was used for sizing the filter area required under each operating condition. The modelling results showed that there was excellent agreement between the predicted and experimental data with a regression coefficient (R 2 ) of 0.98. The developed ANN model was used for performing variable depth filter sizing for different clarification lots. Monte-Carlo simulation was performed to estimate the cost savings by using different filter areas for different clarification lots rather than using the same filter area. A 10% saving in cost of goods was obtained for this operation. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1436-1443, 2016. © 2016 American Institute of Chemical Engineers.

Speed And Power Control Of An Engine By Modulation Of The Load Torque

DOEpatents

Ziph, Benjamin; Strodtman, Scott; Rose, Thomas K

1999-01-26

A system and method of speed and power control for an engine in which speed and power of the engine is controlled by modulation of the load torque. The load torque is manipulated in order to cause engine speed, and hence power to be changed. To accomplish such control, the load torque undergoes a temporary excursion in the opposite direction of the desired speed and power change. The engine and the driven equipment will accelerate or decelerate accordingly as the load torque is decreased or increased, relative to the essentially fixed or constant engine torque. As the engine accelerates or decelerates, its power increases or decreases in proportion.

Compound Velocity Synchronizing Control Strategy for Electro-Hydraulic Load Simulator and Its Engineering Application.

PubMed

Han, Songshan; Jiao, Zongxia; Yao, Jianyong; Shang, Yaoxing

2014-09-01

An electro-hydraulic load simulator (EHLS) is a typical case of torque systems with strong external disturbances from hydraulic motion systems. A new velocity synchronizing compensation strategy is proposed in this paper to eliminate motion disturbances, based on theoretical and experimental analysis of a structure invariance method and traditional velocity synchronizing compensation controller (TVSM). This strategy only uses the servo-valve's control signal of motion system and torque feedback of torque system, which could avoid the requirement on the velocity and acceleration signal in the structure invariance method, and effectively achieve a more accurate velocity synchronizing compensation in large loading conditions than a TVSM. In order to facilitate the implementation of this strategy in engineering cases, the selection rules for compensation parameters are proposed. It does not rely on any accurate information of structure parameters. This paper presents the comparison data of an EHLS with various typical operating conditions using three controllers, i.e., closed loop proportional integral derivative (PID) controller, TVSM, and the proposed improved velocity synchronizing controller. Experiments are conducted to confirm that the new strategy performs well against motion disturbances. It is more effective to improve the tracking accuracy and is a more appropriate choice for engineering applications.

Performance evaluation of an advanced air-fuel ratio controller on a stationary, rich-burn natural gas engine

NASA Astrophysics Data System (ADS)

Kochuparampil, Roshan Joseph

The advent of an era of abundant natural gas is making it an increasingly economical fuel source against incumbents such as crude oil and coal, in end-use sectors such as power generation, transportation and industrial chemical production, while also offering significant environmental benefits over these incumbents. Equipment manufacturers, in turn, are responding to widespread demand for power plants optimized for operation with natural gas. In several applications such as distributed power generation, gas transmission, and water pumping, stationary, spark-ignited, natural gas fueled internal combustion engines (ICEs) are the power plant of choice (over turbines) owing to their lower equipment and operational costs, higher thermal efficiencies across a wide load range, and the flexibility afforded to end-users when building fine-resolution horsepower topologies: modular size increments ranging from 100 kW -- 2 MW per ICE power plant compared to 2 -- 5 MW per turbine power plant. Under the U.S. Environment Protection Agency's (EPA) New Source Performance Standards (NSPS) and Reciprocating Internal Combustion Engine National Emission Standards for Hazardous Air Pollutants (RICE NESHAP) air quality regulations, these natural gas power plants are required to comply with stringent emission limits, with several states mandating even stricter emissions norms. In the case of rich-burn or stoichiometric natural gas ICEs, very high levels of sustained emissions reduction can be achieved through exhaust after-treatment that utilizes Non Selective Catalyst Reduction (NSCR) systems. The primary operational constraint with these systems is the tight air-fuel ratio (AFR) window of operation that needs to be maintained if the NSCR system is to achieve simultaneous reduction of carbon monoxide (CO), nitrogen oxides (NOx), total hydrocarbons (THC), volatile organic compounds (VOCs), and formaldehyde (CH 2O). Most commercially available AFR controllers utilizing lambda (oxygen) sensor feedback are unable to maintain engine AFR within the required range owing to drift in sensor output over time. In this thesis, the emissions compliance performance of an AFR controller is evaluated over a 6-month period on an engine driving a gas compressor in an active natural gas production field. This AFR controller differentiates itself from other commercially available products by employing a lambda sensor that has been engineered against sensor drift, making it better suited for natural gas engine applications. Also included in this study are the controller's responses to transient loads, diurnal performance, adaptability to seasonal variations in ambient temperature, fuel quality variations (in wellhead gas), engine health considerations for proper AFR control, and controller calibration sensitivity when replacing lambda sensors. During the first three months of operation and subsequent diurnal tests, the controller's performance as a multi-point AFR control system was consistent, demonstrating appropriate AFR adjustments to variation in engine operation, over a wide range of ambient conditions, despite high consumption rate of engine lubrication oil. For the remainder the test, the high levels of lubrication oil consumption, compromised the ability to verify controller performance.

Performance and Exhaust Emissions in a Natural-Gas Fueled Dual-Fuel Engine

NASA Astrophysics Data System (ADS)

Shioji, Masahiro; Ishiyama, Takuji; Ikegami, Makoto; Mitani, Shinichi; Shibata, Hiroaki

In order to establish the optimum fueling in a natural gas fueled dual fuel engine, experiments were done for some operational parameters on the engine performances and the exhaust emissions. The results show that the pilot fuel quantity should be increased and its injection timing should be advanced to suppress unburned hydrocarbon emission in the middle and low output range, while the quantity should be reduced and the timing retarded to avoid onset of knock at high loads. Unburned hydrocarbon emission and thermal efficiency are improved by avoiding too lean natural gas mixture by restricting intake charge air. However, the improvement is limited because the ignition of pilot fuel deteriorates with excessive throttling. It is concluded that an adequate combination of throttle control and equivalence ratio ensures low hydrocarbon emission and the thermal efficiency comparable to diesel operation.

Comparative Performance Assessment of 5kW-Class Solid Oxide Fuel Cell Engines Integrated With Single/Dual-Spool Turbochargers

DTIC Science & Technology

2011-01-01

Comparative Performance Assessment of 5kW-Class Solid Oxide Fuel Cell Engines Integrated with Single/Dual-Spool Turbochargers So-Ryeok Oh, Jing Sun... Turbochargers 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT... fundamental operating regime to the part load performance. Two different mechanical designs are assumed: dual shaft and single shaft as the compressor

Viscoplastic analysis of an experimental cylindrical thrust chamber liner

NASA Technical Reports Server (NTRS)

Arya, Vinod K.; Arnold, Steven M.

1991-01-01

A viscoplastic stress-strain analysis of an experimental cylindrical thrust chamber is presented. A viscoelastic constitutive model incorporating a single internal state variable that represents kinematic hardening was employed to investigate whether such a viscoplastic model could predict the experimentally observed behavior of the thrust chamber. Two types of loading cycles were considered: a short cycle of 3.5 sec. duration that corresponded to the experiments, and an extended loading cycle of 485.1 sec. duration that is typical of the Space Shuttle Main Engine (SSME) operating cycle. The analysis qualitatively replicated the deformation behavior of the component as observed in experiments designed to simulate SSME operating conditions. The analysis also showed that the mode and location in the component may depend on the loading cycle. The results indicate that using viscoplastic models for structural analysis can lead to a more realistic life assessment of thrust chambers.

Overview of aerothermodynamic loads definition study

NASA Technical Reports Server (NTRS)

Gaugler, Raymond E.

1989-01-01

Over the years, NASA has been conducting the Advanced Earth-to-Orbit (AETO) Propulsion Technology Program to provide the knowledge, understanding, and design methodology that will allow the development of advanced Earth-to-orbit propulsion systems with high performance, extended service life, automated operations, and diagnostics for in-flight health monitoring. The objective of the Aerothermodynamic Loads Definition Study is to develop methods to more accurately predict the operating environment in AETO propulsion systems, such as the Space Shuttle Main Engine (SSME) powerhead. The approach taken consists of 2 parts: to modify, apply, and disseminate existing computational fluid dynamics tools in response to current needs and to develop new technology that will enable more accurate computation of the time averaged and unsteady aerothermodynamic loads in the SSME powerhead. The software tools are detailed. Significant progress was made in the area of turbomachinery, where there is an overlap between the AETO efforts and research in the aeronautical gas turbine field.

Beam Test of a Dielectric Loaded High Pressure RF Cavity for Use in Muon Cooling Channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freemire, Ben; Bowring, Daniel; Kochemirovskiy, Alexey

2016-06-01

Bright muon sources require six dimensional cooling to achieve acceptable luminosities. Ionization cooling is the only known method able to do so within the muon lifetime. One proposed cooling channel, the Helical Cooling Channel, utilizes gas filled radio frequency cavities to both mitigate RF breakdown in the presence of strong, external magnetic fields, and provide the cooling medium. Engineering constraints on the diameter of the magnets within which these cavities operate dictate the radius of the cavities be decreased at their nominal operating frequency. To accomplish this, one may load the cavities with a larger dielectric material. A 99.5% aluminamore » ring was inserted in a high pressure RF test cell and subjected to an intense proton beam at the MuCool Test Area at Fermilab. The results of the performance of this dielectric loaded high pressure RF cavity will be presented.« less

Engineering test facility design definition

NASA Technical Reports Server (NTRS)

Bercaw, R. W.; Seikel, G. R.

1980-01-01

The Engineering Test Facility (ETF) is the major focus of the Department of Energy (DOE) Magnetohydrodynamics (MHD) Program to facilitate commercialization and to demonstrate the commercial operability of MHD/steam electric power. The ETF will be a fully integrated commercial prototype MHD power plant with a nominal output of 200 MW sub e. Performance of this plant is expected to meet or surpass existing utility standards for fuel, maintenance, and operating costs; plant availability; load following; safety; and durability. It is expected to meet all applicable environmental regulations. The current design concept conforming to the general definition, the basis for its selection, and the process which will be followed in further defining and updating the conceptual design.

Space Electronic Test Engineering

NASA Technical Reports Server (NTRS)

Chambers, Rodney D.

2004-01-01

The Space Power and Propulsion Test Engineering Branch at NASA Glenn Research center has the important duty of controlling electronic test engineering services. These services include test planning and early assessment of Space projects, management and/or technical support required to safely and effectively prepare the article and facility for testing, operation of test facilities, and validation/delivery of data to customer. The Space Electronic Test Engineering Branch is assigned electronic test engineering responsibility for the GRC Space Simulation, Microgravity, Cryogenic, and Combustion Test Facilities. While working with the Space Power and Propulsion Test Engineering Branch I am working on several different assignments. My primary assignment deals with an electrical hardware unit known as Sunny Boy. Sunny Boy is a DC load Bank that is designed for solar arrays in which it is used to convert DC power form the solar arrays into AC power at 60 hertz to pump back into the electricity grid. However, there are some researchers who decided that they would like to use the Sunny Boy unit in a space simulation as a DC load bank for a space shuttle or even the International Space Station hardware. In order to do so I must create a communication link between a computer and the Sunny Boy unit so that I can preset a few of the limits (such power, set & constant voltage levels) that Sunny Boy will need to operate using the applied DC load. Apart from this assignment I am also working on a hi-tech circuit that I need to have built at a researcher s request. This is a high voltage analog to digital circuit that will be used to record data from space ion propulsion rocket booster tests. The problem that makes building this circuit so difficult is that it contains high voltage we must find a way to lower the voltage signal before the data is transferred into the computer to be read. The solution to this problem was to transport the signal using infrared light which will lower the voltage signal down low enough so that it is harmless to a computer. Along with my involvement in the Space Power and Propulsion Test Engineering Branch, I am obligated to assist all other members of the branch in their work. This will help me to strengthen and extend my knowledge of Electrical Engineering.

Performance of a Laser Ignited Multicylinder Lean Burn Natural Gas Engine

DOE PAGES

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

2017-06-06

Market demands for lower fueling costs and higher specific powers in stationary natural gas engines has engine designs trending towards higher in-cylinder pressures and leaner combustion operation. However, Ignition remains as the main limiting factor in achieving further performance improvements in these engines. Addressing this concern, while incorporating various recent advances in optics and laser technologies, laser igniters were designed and developed through numerous iterations. Final designs incorporated water-cooled, passively Q-switched, Nd:YAG micro-lasers that were optimized for stable operation under harsh engine conditions. Subsequently, the micro-lasers were installed in the individual cylinders of a lean-burn, 350 kW, inline 6-cylinder, open-chamber,more » spark ignited engine and tests were conducted. To the best of our knowledge, this is the world’s first demonstration of a laser ignited multi-cylinder natural gas engine. The engine was operated at high-load (298 kW) and rated speed (1800 rpm) conditions. Ignition timing sweeps and excess-air ratio (λ) sweeps were performed while keeping the NOx emissions below the USEPA regulated value (BSNOx < 1.34 g/kW-hr), and while maintaining ignition stability at industry acceptable values (COV_IMEP <5 %). Through such engine tests, the relative merits of (i) standard electrical ignition system, and (ii) laser ignition system were determined. In conclusion, a rigorous combustion data analysis was performed and the main reasons leading to improved performance in the case of laser ignition were identified.« less

Performance of a Laser Ignited Multicylinder Lean Burn Natural Gas Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

Market demands for lower fueling costs and higher specific powers in stationary natural gas engines has engine designs trending towards higher in-cylinder pressures and leaner combustion operation. However, Ignition remains as the main limiting factor in achieving further performance improvements in these engines. Addressing this concern, while incorporating various recent advances in optics and laser technologies, laser igniters were designed and developed through numerous iterations. Final designs incorporated water-cooled, passively Q-switched, Nd:YAG micro-lasers that were optimized for stable operation under harsh engine conditions. Subsequently, the micro-lasers were installed in the individual cylinders of a lean-burn, 350 kW, inline 6-cylinder, open-chamber,more » spark ignited engine and tests were conducted. To the best of our knowledge, this is the world’s first demonstration of a laser ignited multi-cylinder natural gas engine. The engine was operated at high-load (298 kW) and rated speed (1800 rpm) conditions. Ignition timing sweeps and excess-air ratio (λ) sweeps were performed while keeping the NOx emissions below the USEPA regulated value (BSNOx < 1.34 g/kW-hr), and while maintaining ignition stability at industry acceptable values (COV_IMEP <5 %). Through such engine tests, the relative merits of (i) standard electrical ignition system, and (ii) laser ignition system were determined. In conclusion, a rigorous combustion data analysis was performed and the main reasons leading to improved performance in the case of laser ignition were identified.« less

Emissions from diesel versus biodiesel fuel used in a CRDI SUV engine: PM mass and chemical composition.

PubMed

Gangwar, Jitendra; Gupta, Tarun; Gupta, Sudhir; Agarwal, Avinash K

2011-07-01

The diesel tailpipe emissions typically undergo substantial physical and chemical transformations while traveling through the tailpipe, which tend to modify the original characteristics of the diesel exhaust. Most of the health-related attention for diesel exhaust has focused on the carcinogenic potential of inhaled exhaust components, particularly the highly respirable diesel particulate matter (DPM). In the current study, parametric investigations were made using a modern automotive common rail direct injection (CRDI) sports utility vehicle (SUV) diesel engine operated at different loads at constant engine speed (2400 rpm), employing diesel and 20% biodiesel blends (B20) produced from karanja oil. A partial flow dilution tunnel was employed to measure the mass of the primary particulates from diesel and biodiesel blend on a 47-mm quartz substrate. This was followed by chemical analysis of the particulates collected on the substrate for benzene-soluble organic fraction (BSOF) (marker of toxicity). BSOF results showed decrease in its level with increasing engine load for both diesel and biodiesel. In addition, real-time measurements for organic carbon/elemental carbon (OC/EC), and polycyclic aromatic hydrocarbons (PAHs) (marker of toxicity) were carried out on the diluted primary exhaust coming out of the partial flow dilution tunnel. PAH concentrations were found to be the maximum at 20% rated engine load for both the fuels. The collected particulates from diesel and biodiesel-blend exhaust were also analyzed for concentration of trace metals (marker of toxicity), which revealed some interesting results.

Eucalyptus Biodiesel as an Alternative to Diesel Fuel: Preparation and Tests on DI Diesel Engine

PubMed Central

Tarabet, Lyes; Loubar, Khaled; Lounici, Mohand Said; Hanchi, Samir; Tazerout, Mohand

2012-01-01

Nowadays, the increasing oil consumption throughout the world induces crucial economical, security, and environmental problems. As a result, intensive researches are undertaken to find appropriate substitution to fossil fuels. In view of the large amount of eucalyptus trees present in arid areas, we focus in this study on the investigation of using eucalyptus biodiesel as fuel in diesel engine. Eucalyptus oil is converted by transesterification into biodiesel. Eucalyptus biodiesel characterization shows that the physicochemical properties are comparable to those of diesel fuel. In the second phase, a single cylinder air-cooled, DI diesel engine was used to test neat eucalyptus biodiesel and its blends with diesel fuel in various ratios (75, 50, and 25 by v%) at several engine loads. The engine combustion parameters such as peak pressure, rate of pressure rise, and heat release rate are determined. Performances and exhaust emissions are also evaluated at all operating conditions. Results show that neat eucalyptus biodiesel and its blends present significant improvements of carbon monoxide, unburned hydrocarbon, and particulates emissions especially at high loads with equivalent performances to those of diesel fuel. However, the NOx emissions are slightly increased when the biodiesel content is increased in the blend. PMID:22675246

Eucalyptus biodiesel as an alternative to diesel fuel: preparation and tests on DI diesel engine.

PubMed

Tarabet, Lyes; Loubar, Khaled; Lounici, Mohand Said; Hanchi, Samir; Tazerout, Mohand

2012-01-01

Nowadays, the increasing oil consumption throughout the world induces crucial economical, security, and environmental problems. As a result, intensive researches are undertaken to find appropriate substitution to fossil fuels. In view of the large amount of eucalyptus trees present in arid areas, we focus in this study on the investigation of using eucalyptus biodiesel as fuel in diesel engine. Eucalyptus oil is converted by transesterification into biodiesel. Eucalyptus biodiesel characterization shows that the physicochemical properties are comparable to those of diesel fuel. In the second phase, a single cylinder air-cooled, DI diesel engine was used to test neat eucalyptus biodiesel and its blends with diesel fuel in various ratios (75, 50, and 25 by v%) at several engine loads. The engine combustion parameters such as peak pressure, rate of pressure rise, and heat release rate are determined. Performances and exhaust emissions are also evaluated at all operating conditions. Results show that neat eucalyptus biodiesel and its blends present significant improvements of carbon monoxide, unburned hydrocarbon, and particulates emissions especially at high loads with equivalent performances to those of diesel fuel. However, the NOx emissions are slightly increased when the biodiesel content is increased in the blend.

Collection of ultrafine diesel particulate matter (DPM) in cylindrical single-stage wet electrostatic precipitators.

PubMed

Saiyasitpanich, Phirun; Keener, Tim C; Lu, Mingming; Khang, Soon-Jai; Evans, Douglas E

2006-12-15

Long-term exposures to diesel particulate matter (DPM) emissions are linked to increasing adverse human health effects due to the potential association of DPM with carcinogenicity. Current diesel vehicular particulate emission regulations are based solely upon total mass concentration, albeit it is the submicrometer particles that are highly respirable and the most detrimental to human health. In this study, experiments were performed with a tubular single-stage wet electrostatic precipitator (wESP) to evaluate its performance for the removal of number-based DPM emissions. A nonroad diesel generator utilizing a low sulfur diesel fuel (500 ppmw) operating under varying load conditions was used as a stationary DPM emission source. An electrical low-pressure impactor (ELPI) was used to quantify the number concentration distributions of diesel particles in the diluted exhaust gas at each tested condition. The wESP was evaluated with respect to different operational control parameters such as applied voltage, gas residence time, etc., to determine their effect on overall collection efficiency, as well as particle size dependent collection efficiency. The results show that the total DPM number concentrations in the untreated diesel exhaust are in the magnitude of approximately108/cm(3) at all engine loads with the particle diameter modes between 20 and 40 nm. The measured collection efficiency of the wESP operating at 70 kV based on total particle numbers was 86% at 0 kW engine load and the efficiency decreased to 67% at 75 kW due to a decrease in gas residence time and an increase in particle concentrations. At a constant wESP voltage of 70 kV and at 75 kW engine load, the variation of gas residence time within the wESP from approximately 0.1 to approximately 0.4 s led to a substantial increase in the collection efficiency from 67% to 96%. In addition, collection efficiency was found to be directly related to the applied voltage, with increasing collection efficiency measured for increases in applied voltage. The collection efficiency based on particle size had a minimum for sizes between 20 and 50 nm, but at optimal wESP operating conditions it was possible to remove over 90% of all particle sizes. A comparison of measured and calculated collection efficiencies reveals that the measured values are significantly higher than the predicted values based on the well-known Deutsch equation.

Role of fuel additives on reduction of NOX emission from a diesel engine powered by camphor oil biofuel.

PubMed

Subramanian, Thiyagarajan; Varuvel, Edwin Geo; Ganapathy, Saravanan; Vedharaj, S; Vallinayagam, R

2018-06-01

The present study intends to explore the effect of the addition of fuel additives with camphor oil (CMO) on the characteristics of a twin-cylinder compression ignition (CI) engine. The lower viscosity and boiling point of CMO when compared to diesel could improve the fuel atomization, evaporation, and air/fuel mixing process. However, the lower cetane index of CMO limits its use as a drop in fuel for diesel in CI engine. In general, NO X emission increases for less viscous and low cetane (LVLC) fuels due to pronounced premixed combustion phase. To improve the ignition characteristics and decrease NO X emissions, fuel additives such as diglyme (DGE)-a cetane enhancer, cumene (CU)-an antioxidant, and eugenol (EU) and acetone (A)-bio-additives, are added 10% by volume with CMO. The engine used for the experimentation is a twin-cylinder tractor engine that runs at a constant speed of 1500 rpm. The engine was operated with diesel initially to attain warm-up condition, which facilitates the operation of neat CMO. At full load condition, brake thermal efficiency (BTE) for CMO is higher (29.6%) than that of diesel (28.1%), while NO X emission is increased by 9.4%. With DGE10 (10% DGE + 90% CMO), the ignition characteristics of CMO are improved and BTE is increased to 31.7% at full load condition. With EU10 (10% EU + 90% CMO) and A10 (10% A + 90% CMO), NO X emission is decreased by 24.6 and 17.8% when compared to diesel, while BTE is comparable to diesel. While HC and CO emission decreased for DGE10 and CU10, they increased for EU10 and A10 when compared to baseline diesel and CMO.

Nacelle Aerodynamic and Inertial Loads (NAIL) project

NASA Technical Reports Server (NTRS)

1982-01-01

A flight test survey of pressures measured on wing, pylon, and nacelle surfaces and of the operating loads on Boeing 747/Pratt & Whitney JT9D-7A nacelles was made to provide information on airflow patterns surrounding the propulsion system installations and to clarify processes responsible for inservice deterioration of fuel economy. Airloads at takeoff rotation were found to be larger than at any other normal service condition because of the combined effects of high angle of attack and high engine airflow. Inertial loads were smaller than previous estimates indicated. A procedure is given for estimating inlet airloads at low speeds and high angles of attack for any underwing high bypass ratio turbofan installation approximately resembling the one tested. Flight procedure modifications are suggested that may result in better fuel economy retention in service. Pressures were recorded on the core cowls and pylons of both engine installations and on adjacent wing surfaces for use in development of computer codes for analysis of installed propulsion system aerodynamic drag interference effects.

Ultrafine particle emissions by in-use diesel buses of various generations at low-load regimes

NASA Astrophysics Data System (ADS)

Tartakovsky, L.; Baibikov, V.; Comte, P.; Czerwinski, J.; Mayer, A.; Veinblat, M.; Zimmerli, Y.

2015-04-01

Ultrafine particles (UFP) are major contributors to air pollution due to their easy gas-like penetration into the human organism, causing adverse health effects. This study analyzes UFP emissions by buses of different technologies (from Euro II till Euro V EEV - Enhanced Environmentally-friendly Vehicle) at low-load regimes. Additionally, the emission-reduction potential of retrofitting with a diesel particle filter (DPF) is demonstrated. A comparison of the measured, engine-out, particle number concentrations (PNC) for buses of different technological generations shows that no substantial reduction of engine-out emissions at low-load operating modes is observed for newer bus generations. Retrofitting the in-use urban and interurban buses of Euro II till Euro IV technologies by the VERT-certified DPF confirmed its high efficiency in reduction of UFP emissions. Particle-count filtration efficiency values of the retrofit DPF were found to be extremely high - greater than 99.8%, similar to that of the OEM filter in the Euro V bus.

Development of an Aeroelastic Modeling Capability for Transient Nozzle Side Load Analysis

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

2013-01-01

Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development. Currently there is no fully coupled computational tool to analyze this fluid/structure interaction process. The objective of this study was to develop a fully coupled aeroelastic modeling capability to describe the fluid/structure interaction process during the transient nozzle operations. The aeroelastic model composes of three components: the computational fluid dynamics component based on an unstructured-grid, pressure-based computational fluid dynamics formulation, the computational structural dynamics component developed in the framework of modal analysis, and the fluid-structural interface component. The developed aeroelastic model was applied to the transient nozzle startup process of the Space Shuttle Main Engine at sea level. The computed nozzle side loads and the axial nozzle wall pressure profiles from the aeroelastic nozzle are compared with those of the published rigid nozzle results, and the impact of the fluid/structure interaction on nozzle side loads is interrogated and presented.

Energy, variability and weather finance engineering

NASA Astrophysics Data System (ADS)

Roussis, Dimitrios; Parara, Iliana; Gournari, Panagiota; Moustakis, Yiannis; Dimitriadis, Panayiotis; Iliopoulou, Theano; Koutsoyiannis, Demetris; Karakatsanis, Georgios

2017-04-01

Most types of renewable energies are characterized by intense intermittency, causing significant instabilities to the grid; further requiring additional infrastructure (e.g. pumped-storage) for buffering hydrometeorological uncertainties, as well as complex operational rules for load balancing. In addition, most intermittent renewable units are subsidized, creating significant market inefficiencies. Weather derivatives comprise mature financial tools for integrating successfully the intermittent-load and base-load components into a unified hybrid energy system and establish their operation within a generalized uncertainty management market. With a growing global market share and 46% utilization of this financial tool by the energy industry and 12% by agriculture (that partially concerns biofuel resources), weather derivatives are projected to constitute a critical subsystem of many grids for buffering frequent hydrometeorological risks of low and medium impacts -which are not covered by standard insurance contracts that aim exclusively at extreme events and high financial damages. In this context, we study the attributes of hydrometeorological time series in a remote and small island in Greece, powered by an autonomous hybrid energy system. Upon the results we choose the optimal underlying index and we further compose and engineer a weather derivative with features of a typical option contract -which we consider most flexible and appropriate for the case- to test our assumptions on its beneficiary effects for both the budget of private energy producers and the island's public administration. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

Design and Performance of LPG Fuel Mixer for Dual Fuel Diesel Engine

NASA Astrophysics Data System (ADS)

Desrial; Saputro, W.; Garcia, P. P.

2018-05-01

Small horizontal diesel engines are commonly used for agricultural machinery, however, availability of diesel fuel become one of big problems especially in remote area. Conversely, in line with government policy for conversion of kerosene into LPG for cooking, then LPG become more popular and available even in remote area. Therefore, LPG is potential fuel to replace the shortage of diesel fuel for operating diesel engine in remote area. The purpose of this study was to design mixing device for using dual fuel i.e. LPG and diesel fuel and evaluate its performance accordingly. Simulation by using CFD was done in order to analyze mixture characteristics of LPG in air intake manifold. The performance test was done by varying the amount of LPG injected in intake air at 20%, 25%, 30%, 35%, until 40%, respectively. Result of CFD contour simulation showed the best combination when mixing 30% LPG into the intake air. Performance test of this research revealed that mixing LPG in air intake can reduce the diesel fuel consumption about 0.7 l/hour (without load) and 1.14 l/hour (with load). Diesel engine revolution increases almost 300 rpm faster than when using diesel fuel only. Based on economic analysis, using the fuel combination (diesel fuel – LPG) is not recommended in the area near SPBU where the price of diesel fuel is standard. However, using the fuel combination LPG-diesel fuel is highly recommended in the remote areas in Indonesia where price of diesel fuel is comparatively expensive which will provide cheaper total fuel cost for diesel engine operation.

Experimental investigation of regulated and unregulated emissions from a diesel engine fueled with ultralow-sulfur diesel fuel blended with ethanol and dodecanol

NASA Astrophysics Data System (ADS)

Cheung, C. S.; Di, Yage; Huang, Zuohua

Experiments were conducted on a four-cylinder direct-injection diesel engine using ultralow-sulfur diesel as the main fuel, ethanol as the oxygenate additive and dodecanol as the solvent, to investigate the regulated and unregulated emissions of the engine under five engine loads at an engine speed of 1800 rev min -1. Blended fuels containing 6.1%, 12.2%, 18.2% and 24.2% by volume of ethanol, corresponding to 2%, 4%, 6% and 8% by mass of oxygen in the blended fuel, were used. The results indicate that with an increase in ethanol in the fuel, the brake specific fuel consumption becomes higher while there is little change in the brake thermal efficiency. Regarding the regulated emissions, HC and CO increase significantly at low engine load but might decrease at high engine load, NO x emission slightly decreases at low engine load but slightly increases at high engine load, while particulate mass decreases significantly at high engine load. For the unregulated gaseous emissions, unburned ethanol and acetaldehyde increase but formaldehyde, ethene, ethyne, 1,3-butadiene and BTX (benzene, toluene and xylene) in general decrease, especially at high engine load. A diesel oxidation catalyst (DOC) is found to reduce significantly most of the pollutants, including the air toxics.

Direct Numerical Simulations of Microstructure Effects During High-Rate Loading of Additively Manufactured Metals

NASA Astrophysics Data System (ADS)

Battaile, Corbett; Owen, Steven; Moore, Nathan

2017-06-01

The properties of most engineering materials depend on the characteristics of internal microstructures and defects. In additively manufactured (AM) metals, these can include polycrystalline grains, impurities, phases, and significant porosity that qualitatively differ from conventional engineering materials. The microscopic details of the interactions between these internal defects, and the propagation of applied loads through the body, act in concert to dictate macro-observable properties like strength and compressibility. In this work, we used Sandia's ALEGRA finite element software to simulate the high-strain-rate loading of AM metals from laser engineered net shaping (LENS) and thermal spraying. The microstructural details of the material were represented explicitly, such that internal features like second phases and pores are captured and meshed as individual entities in the computational domain. We will discuss the dependence of the high-strain-rate mechanical properties on microstructural characteristics such as the shapes, sizes, and volume fractions of second phases and pores. In addition, we will examine how the details of the microstructural representation affect the microscopic material response to dynamic loads, and the effects of using ``stair-step'' versus conformal interfaces smoothed via the SCULPT tool in Sandia's CUBIT software. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the US DOE NNSA under contract DE-AC04-94AL85000.

Design and optimization of smart grid system based on renewable energy in Nyamuk Island, Karimunjawa district, Central Java

NASA Astrophysics Data System (ADS)

Novitasari, D.; Indartono, Y. S.; Rachmidha, T. D.; Reksowardojo, I. K.; Irsyad, M.

2017-03-01

Nyamuk Island in Karimunjawa District is one of the regions in Java that has no access to electricity grid. The electricity in Nyamuk Island relies on diesel engine which is managed by local government and only operated for 6 hours per day. It occurs as a consequence of high fuel cost. A study on smart micro grid system based on renewable energy was conducted in Combustion Engine and Propulsion System Laboratory of Institut Teknologi Bandung by using 1 kWp solar panels and a 3 kW bio based diesel engine. The fuels used to run the bio based diesel engine were diesel, virgin coconut oil and pure palm oil. The results show that the smart grid system run well at varying load and also with different fuel. Based on the experiments, average inverter efficiency was about 87%. This experiments proved that the use of biofuels had no effects to the overall system performance. Based on the results of prototype experiments, this paper will focus on design and optimization of smart micro grid system using HOMER software for Nyamuk Island. The design consists of (1) a diesel engine existing in Nyamuk Island whose fuel was diesel, (2) a lister engine whose fuel was from vegetable oil from Callophyllum inophyllum, (3) solar panels, (4) batteries and (5) converter. In this simulation, the existing diesel engine was set to operate 2 hours per day, while operating time of the lister engine has been varied with several scenarios. In scenario I, the lister engine was operated 5 hours per day, in scenario II the lister engine was operated 24 hours per day and in scenario III the lister engine was operated 8 hours per week in the weekend. In addition, a design using a modified diesel engine was conducted as well with an assumption that the modified cost was about 10% of new diesel engine cost. By modifying the diesel engine, the system will not need a lister engine. Assessments has been done to evaluate the designs, and the result shows that the optimal value obtains by the lister engine being operated for 24 hours a day in which the capacity of each component was 27 kWp PV, 7 kW lister engine, 26 kVA existing diesel engine, 40 kW converter and 128 batteries. The result is based on the lowest value of Net Present Cost (NPC) of 542.682 and Cost Of Electricity (COE) of 0.49.

Mechanical Properties Experimental Study of Engineering Vehicle Refurbished Tire

NASA Astrophysics Data System (ADS)

Qiang, Wang; Xiaojie, Qi; Zhao, Yang; Yunlong, Wang; Guotian, Wang; Degang, Lv

2018-05-01

The vehicle refurbished tire test system was constructed, got load-deformation, load-stiffness, and load-compression ratio property laws of engineering vehicle refurbished tire under the working condition of static state and ground contact, and built radial direction loading deformation mathematics model of 26.5R25 engineering vehicle refurbished tire. The test results show that radial-direction and side-direction deformation value is a little less than that of the new tire. The radial-direction stiffness and compression ratio of engineering vehicle refurbished tire were greatly influenced by radial-direction load and air inflation pressure. When load was certain, radial-direction stiffness would increase with air inflation pressure increasing. When air inflation pressure was certain, compression ratio of engineering vehicle refurbished tire would enlarge with radial-direction load increasing, which was a little less than that of the new and the same type tire. Aging degree of old car-case would exert a great influence on deformation property of engineering vehicle refurbished tire, thus engineering vehicle refurbished tires are suitable to the working condition of low tire pressure and less load.

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.

An optical method for measuring exhaust gas pressure from an internal combustion engine at high speed

NASA Astrophysics Data System (ADS)

Leach, Felix C. P.; Davy, Martin H.; Siskin, Dmitrij; Pechstedt, Ralf; Richardson, David

2017-12-01

Measurement of exhaust gas pressure at high speed in an engine is important for engine efficiency, computational fluid dynamics analysis, and turbocharger matching. Currently used piezoresistive sensors are bulky, require cooling, and have limited lifetimes. A new sensor system uses an interferometric technique to measure pressure by measuring the size of an optical cavity, which varies with pressure due to movement of a diaphragm. This pressure measurement system has been used in gas turbine engines where the temperatures and pressures have no significant transients but has never been applied to an internal combustion engine before, an environment where both temperature and pressure can change rapidly. This sensor has been compared with a piezoresistive sensor representing the current state-of-the-art at three engine operating points corresponding to both light load and full load. The results show that the new sensor can match the measurements from the piezoresistive sensor except when there are fast temperature swings, so the latter part of the pressure during exhaust blowdown is only tracked with an offset. A modified sensor designed to compensate for these temperature effects is also tested. The new sensor has shown significant potential as a compact, durable sensor, which does not require external cooling.

An optical method for measuring exhaust gas pressure from an internal combustion engine at high speed.

PubMed

Leach, Felix C P; Davy, Martin H; Siskin, Dmitrij; Pechstedt, Ralf; Richardson, David

2017-12-01

Measurement of exhaust gas pressure at high speed in an engine is important for engine efficiency, computational fluid dynamics analysis, and turbocharger matching. Currently used piezoresistive sensors are bulky, require cooling, and have limited lifetimes. A new sensor system uses an interferometric technique to measure pressure by measuring the size of an optical cavity, which varies with pressure due to movement of a diaphragm. This pressure measurement system has been used in gas turbine engines where the temperatures and pressures have no significant transients but has never been applied to an internal combustion engine before, an environment where both temperature and pressure can change rapidly. This sensor has been compared with a piezoresistive sensor representing the current state-of-the-art at three engine operating points corresponding to both light load and full load. The results show that the new sensor can match the measurements from the piezoresistive sensor except when there are fast temperature swings, so the latter part of the pressure during exhaust blowdown is only tracked with an offset. A modified sensor designed to compensate for these temperature effects is also tested. The new sensor has shown significant potential as a compact, durable sensor, which does not require external cooling.

A thermoacoustic-Stirling heat engine: detailed study

PubMed

Backhaus; Swift

2000-06-01

A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described. Measurements and analysis of its performance are presented. This new engine outperforms previous thermoacoustic engines, which are based on standing waves and intrinsically irreversible heat transfer, by more than 50%. At its most efficient operating point, it delivers 710 W of acoustic power to its resonator with a thermal efficiency of 0.30, corresponding to 41% of the Carnot efficiency. At its most powerful operating point, it delivers 890 W to its resonator with a thermal efficiency of 0.22. The efficiency of this engine can be degraded by two types of acoustic streaming. These are suppressed by appropriate tapering of crucial surfaces in the engine and by using additional nonlinearity to induce an opposing time-averaged pressure difference. Data are presented which show the nearly complete elimination of the streaming convective heat loads. Analysis of these and other irreversibilities show which components of the engine require further research to achieve higher efficiency. Additionally, these data show that the dynamics and acoustic power flows are well understood, but the details of the streaming suppression and associated heat convection are only qualitatively understood.

A Study on Performance, Combustion and Emission Characteristics of Compression Ignition Engine Using Fish Oil Biodiesel Blends

NASA Astrophysics Data System (ADS)

Ramesha, D. K.; Thimmannachar, Rajiv K.; Simhasan, R.; Nagappa, Manjunath; Gowda, P. M.

2012-07-01

Bio-fuel is a clean burning fuel made from natural renewable energy resource; it operates in C. I. engine similar to the petroleum diesel. The rising cost of diesel and the danger caused to the environment has led to an intensive and desperate search for alternative fuels. Among them, animal fats like the fish oil have proven to be a promising substitute to diesel. In this experimental study, A computerized 4-stroke, single cylinder, constant speed, direct injection diesel engine was operated on fish oil-biodiesel of different blends. Three different blends of 10, 20, and 30 % by volume were used for this study. Various engine performance, combustion and emission parameters such as Brake Thermal Efficiency, Brake Specific Fuel Consumption, Heat Release Rate, Peak Pressure, Exhaust Gas Temperature, etc. were recorded from the acquired data. The data was recorded with the help of an engine analysis software. The recorded parameters were studied for varying loads and their corresponding graphs have been plotted for comparison purposes. Petroleum Diesel has been used as the reference. From the properties and engine test results it has been established that fish oil biodiesel is a better replacement for diesel without any engine modification.

Engine System Loads Development for the Fastrac 60K Flight Engine

NASA Technical Reports Server (NTRS)

Frady, Greg; Christensen, Eric R.; Mims, Katherine; Harris, Don; Parks, Russell; Brunty, Joseph

2000-01-01

Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However, with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the new Fastrac engine program, the focus has been to reduce the cost to weight ratio; current structural dynamics analysis practices were tailored in order to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of Fastrac load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are discussed.

Load Model Verification, Validation and Calibration Framework by Statistical Analysis on Field Data

NASA Astrophysics Data System (ADS)

Jiao, Xiangqing; Liao, Yuan; Nguyen, Thai

2017-11-01

Accurate load models are critical for power system analysis and operation. A large amount of research work has been done on load modeling. Most of the existing research focuses on developing load models, while little has been done on developing formal load model verification and validation (V&V) methodologies or procedures. Most of the existing load model validation is based on qualitative rather than quantitative analysis. In addition, not all aspects of model V&V problem have been addressed by the existing approaches. To complement the existing methods, this paper proposes a novel load model verification and validation framework that can systematically and more comprehensively examine load model's effectiveness and accuracy. Statistical analysis, instead of visual check, quantifies the load model's accuracy, and provides a confidence level of the developed load model for model users. The analysis results can also be used to calibrate load models. The proposed framework can be used as a guidance to systematically examine load models for utility engineers and researchers. The proposed method is demonstrated through analysis of field measurements collected from a utility system.

Study of a High Voltage Ion Engine Power Supply

NASA Technical Reports Server (NTRS)

Stuart, Thomas A.; King, Roger J.; Mayer, Eric

1996-01-01

A complete laboratory breadboard version of a ion engine power converter was built and tested. This prototype operated on a line voltage of 80-120 Vdc, and provided output ratings of 1100 V at 1.8 kW, and 250 V at 20 mA. The high-voltage (HV) output voltage rating was revised from the original value of 1350 V at the beginning of the project. The LV output was designed to hold up during a 1-A surge current lasting up to 1 second. The prototype power converter included a internal housekeeping power supply which also operated from the line input. The power consumed in housekeeping was included in the overall energy budget presented for the ion engine converter. HV and LV output voltage setpoints were commanded through potentiometers. The HV converter itself reached its highest power efficiency of slightly over 93% at low line and maximum output. This would dip below 90% at high line. The no-load (rated output voltages, zero load current) power consumption of the entire system was less than 13 W. A careful loss breakdown shows that converter losses are predominately Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) conduction losses and HV rectifier snubbing losses, with the rectifier snubbing losses becoming predominant at high line. This suggests that further improvements in power efficiency could best be obtained by either developing a rectifier that was adequately protected against voltage overshoot with less snubbing, or by developing a pre-regulator to reduced the range of line voltage on the converter. The transient testing showed the converter to be fully protected against load faults, including a direct short-circuit from the HV output to the LV output terminals. Two currents sensors were used: one to directly detect any core ratcheting on the output transformer and re-initiate a soft start, and the other to directly detect a load fault and quickly shut down the converter for load protection. The finished converter has been extensively fault tested without failure. The finished converter has been packaged suitable for use as a laboratory prototype for further testing. The finished converter is readily transportable. An article on design issues for high voltage converters for ion engines is included as an attachement.

An Investigation in the Ames 40- by 80-Foot Wind Tunnel of a YT-56A Turboprop Engine Incorporating a Decoupler and a Controlled-Feathering Device

NASA Technical Reports Server (NTRS)

Rogallo, Vernon L.; Yaggy, Paul F.; McCloud, John L., III

1954-01-01

An investigation of a decoupler and a controlled-feathering device incorporated with the YT-56A turboprop engine has been made to determine the effectiveness of these devices in reducing the high negative thrust (drag) which accompanies power failure of this type of engine. Power failures were simulated by fuel cut-off, both without either device free to operate, and with each device free to operate singly. The investigation was made through an airspeed range from 50 to 230 mph. It was found that with neither device free to operate, the drag levels realized after power failures at airspeeds above 170 mph would impose vertical tail loads higher than those allowable for the YC-130, the airplane for which the test power package was designed. These levels were reached in approximately one second. The maximum drag realized after power failure was not appreciably altered by the use of the decoupler although the decoupler did put a limit on the duration of the peak drag. The controlled-feathering device maintained a level of essentially zero drag after power failure. The use of the decoupler in the YT-56A engine complicates windmilling air-starting procedures and makes it necessary to place operating restrictions on the engine to assure safe flight at low-power conditions,

System-Level Design of a Shape Memory Alloy Actuator for Active Clearance Control in the High-Pressure Turbine

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan A.; Melcher, Kevin J.; Noebe, Ronald D.

2005-01-01

This paper describes results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 inches. Design results show that an actuator comprised of 10 wires 2 inches in length is adequate for control at critical engine operating points and still exhibits acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

Evolution of deep-bed filtration of engine exhaust particulates with trapped mass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viswanathan, Sandeep; Rothamer, David A.; Foster, David E.

Micro-scale filtration experiments were performed on cordierite filter samples using particulate matter (PM) generated by a spark-ignition direct-injection (SIDI) engine fueled with tier II EEE certification gasoline. Size-resolved mass and number concentrations were obtained from several engine operating conditions. The resultant mass-mobility relationships showed weak dependence on the operating condition. An integrated particle size distribution (IPSD) method was used estimate the PM mass concentration in the exhaust stream from the SIDI engine and a heavy duty diesel (HDD) engine. The average estimated mass concentration between all conditions was ~77****** % of the gravimetric measurements performed on Teflon filters. Despite themore » relatively low elemental carbon fraction (~0.4 to 0.7), the IPSD mass for stoichiometric SIDI exhaust was ~83±38 % of the gravimetric measurement. Identical cordierite filter samples with properties representative of diesel particulate filters were sequentially loaded with PM from the different SIDI engine operating conditions, in order of increasing PM mass concentration. Simultaneous particle size distribution measurements upstream and downstream of the filter sample were used to evaluate filter performance evolution and the instantaneous trapped mass within the filter for two different filter face velocities. The evolution of filtration performance for the different samples was sensitive only to trapped mass, despite using PM from a wide range of operating conditions. Higher filtration velocity resulted in a more rapid shift in the most penetrating particle size towards smaller mobility diameters.« less

Work production of quantum rotor engines

NASA Astrophysics Data System (ADS)

Seah, Stella; Nimmrichter, Stefan; Scarani, Valerio

2018-04-01

We study the mechanical performance of quantum rotor heat engines in terms of common notions of work using two prototypical models: a mill driven by the heat flow from a hot to a cold mode, and a piston driven by the alternate heating and cooling of a single working mode. We evaluate the extractable work in terms of ergotropy, the kinetic energy associated to net directed rotation, as well as the intrinsic work based on the exerted torque under autonomous operation, and we compare them to the energy output for the case of an external dissipative load and for externally driven engine cycles. Our results connect work definitions from both physical and information-theoretical perspectives. In particular, we find that apart from signatures of angular momentum quantization, the ergotropy is consistent with the intuitive notion of work in the form of net directed motion. It also agrees with the energy output to an external load or agent under optimal conditions. This sets forth a consistent thermodynamical description of rotating quantum motors, flywheels, and clocks.

75 FR 2057 - Airworthiness Directives; Airbus Model A340-200 and A340-300 Series Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-14

... could lead to the loss of the load path for the forward engine mount and damage to other engine mount... loss of the load path for the forward engine mount and damage to other engine mount structures, which... loss of the load path for the forward engine mount and damage to other engine mount structures, which...

Modeling and simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanham, R.; Vogt, W.G.; Mickle, M.H.

1986-01-01

This book presents the papers given at a conference on computerized simulation. Topics considered at the conference included expert systems, modeling in electric power systems, power systems operating strategies, energy analysis, a linear programming approach to optimum load shedding in transmission systems, econometrics, simulation in natural gas engineering, solar energy studies, artificial intelligence, vision systems, hydrology, multiprocessors, and flow models.

76 FR 66660 - Special Conditions: Gulfstream Aerospace LP (GALP) Model G280 Airplane, Operation Without Normal...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-27

... distribution and equipment-loads-demand condition. 2. After the unrestorable loss of normal engine generator... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 25 [Docket No. FAA-2011-1172: Notice No. 25-11-17-SC] Special Conditions: Gulfstream Aerospace LP (GALP) Model G280 Airplane...

Particulate Emissions from Fall Tillage Operations as Determined via Inverse Modeling and Lidar Mass Balance Techniques

USDA-ARS?s Scientific Manuscript database

Preparation of soil for agricultural crops produces aerosols that may significantly contribute to seasonal atmospheric loadings, especially in areas with a high density of perennial crops. Emissions may originate from the tractor’s diesel engine, the tractor moving over the ground, and the equipment...

Oil-Free Turbomachinery Team Passed Milestone on Path to the First Oil-Free Turbine Aircraft Engine

NASA Technical Reports Server (NTRS)

Bream, Bruce L.

2002-01-01

The Oil-Free Turbine Engine Technology Project team successfully demonstrated a foil-air bearing designed for the core rotor shaft of a turbine engine. The bearings were subjected to test conditions representative of the engine core environment through a combination of high speeds, sustained loads, and elevated temperatures. The operational test envelope was defined during conceptual design studies completed earlier this year by bearing manufacturer Mohawk Innovative Technologies and the turbine engine company Williams International. The prototype journal foil-air bearings were tested at the NASA Glenn Research Center. Glenn is working with Williams and Mohawk to create a revolution in turbomachinery by developing the world's first Oil-Free turbine aircraft engine. NASA's General Aviation Propulsion project and Williams International recently developed the FJX-2 turbofan engine that is being commercialized as the EJ-22. This core bearing milestone is a first step toward a future version of the EJ-22 that will take advantage of recent advances in foil-air bearings by eliminating the need for oil lubrication systems and rolling element bearings. Oil-Free technology can reduce engine weight by 15 percent and let engines operate at very high speeds, yielding power density improvements of 20 percent, and reducing engine maintenance costs. In addition, with NASA coating technology, engines can operate at temperatures up to 1200 F. Although the project is still a couple of years from a full engine test of the bearings, this milestone shows that the bearing design exceeds the expected environment, thus providing confidence that an Oil-Free turbine aircraft engine will be attained. The Oil-Free Turbomachinery Project is supported through the Aeropropulsion Base Research Program.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zelenyuk, Alla; Reitz, Paul; Stewart, Mark L.

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 amore » 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.« less

Building Energy Management Open Source Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

This is the repository for Building Energy Management Open Source Software (BEMOSS), which is an open source operating system that is engineered to improve sensing and control of equipment in small- and medium-sized commercial buildings. BEMOSS offers the following key features: (1) Open source, open architecture – BEMOSS is an open source operating system that is built upon VOLTTRON – a distributed agent platform developed by Pacific Northwest National Laboratory (PNNL). BEMOSS was designed to make it easy for hardware manufacturers to seamlessly interface their devices with BEMOSS. Software developers can also contribute to adding additional BEMOSS functionalities and applications.more » (2) Plug & play – BEMOSS was designed to automatically discover supported load controllers (including smart thermostats, VAV/RTUs, lighting load controllers and plug load controllers) in commercial buildings. (3) Interoperability – BEMOSS was designed to work with load control devices form different manufacturers that operate on different communication technologies and data exchange protocols. (4) Cost effectiveness – Implementation of BEMOSS deemed to be cost-effective as it was built upon a robust open source platform that can operate on a low-cost single-board computer, such as Odroid. This feature could contribute to its rapid deployment in small- or medium-sized commercial buildings. (5) Scalability and ease of deployment – With its multi-node architecture, BEMOSS provides a distributed architecture where load controllers in a multi-floor and high occupancy building could be monitored and controlled by multiple single-board computers hosting BEMOSS. This makes it possible for a building engineer to deploy BEMOSS in one zone of a building, be comfortable with its operation, and later on expand the deployment to the entire building to make it more energy efficient. (6) Ability to provide local and remote monitoring – BEMOSS provides both local and remote monitoring ability with role-based access control. (7) Security – In addition to built-in security features provided by VOLTTRON, BEMOSS provides enhanced security features, including BEMOSS discovery approval process, encrypted core-to-node communication, thermostat anti-tampering feature and many more. (8) Support from the Advisory Committee – BEMOSS was developed in consultation with an advisory committee from the beginning of the project. BEMOSS advisory committee comprises representatives from 22 organizations from government and industry.« less

A Nomographic Methodology for Use in Performance Trade-Off Studies of Parabolic Dish Solar Power Modules

NASA Technical Reports Server (NTRS)

Selcuk, M. K.; Fujita, T.

1984-01-01

A simple graphical method was developed to undertake technical design trade-off studies for individual parabolic dish models comprising a two-axis tracking parabolic dish with a cavity receiver and power conversion assembly at the focal point. The results of these technical studies are then used in performing the techno-economic analyses required for determining appropriate subsystem sizing. Selected graphs that characterize the performance of subsystems within the module were arranged in the form of a nomogram that would enable an investigator to carry out several design trade-off studies. Key performance parameters encompassed in the nomogram include receiver losses, intercept factor, engine rating, and engine efficiency. Design and operation parameters such as concentrator size, receiver type (open or windowed aperture), receiver aperture size, operating temperature of the receiver and engine, engine partial load characteristics, concentrator slope error, and the type of reflector surface, are also included in the graphical solution. Cost considerations are not included.

Dynamic Rate Dependent Elastoplastic Damage Modeling of Concrete Subject to Blast Loading: Formulation and Computational Aspects

DTIC Science & Technology

1990-10-31

and ZIP Code) Dept. of Civil Fng. & Oper. Research Building 410 Princeton University Bolling AFB, D.C. 20332-6448 ?rinceton, NJ 08544 i. NAME OF FUNDING...Department of Civil Engineering & Operations Research Princeton University Princeton, N.J. 08544 31 October 1990 Final Technical Report Approved for public...release; Distribution is unlimited. I Prepared for Air Force Office of Scientific Research Building 410 Boiling AFB, D.C. 20332-6448 PREFACE This work

Strategic Reality and Tactical Mirages: Special Operations and the Iranian Hostage Rescue, 1979-1980

DTIC Science & Technology

2017-06-01

additional error. The noise of C -130 engines and whirling helicopter blades made communication nearly impossible at the loading site and added...first chapter will provide an historical overview of Operation Eagle Claw. The narrative conveys what shaped the military and geopolitical environment...of RH-53D helicopters and C -130 aircraft as the best and only mix of assets to overcome the tyranny of distance—the 865 nautical mile flight is the

Design considerations for a Space Shuttle Main Engine turbine blade made of single crystal material

NASA Technical Reports Server (NTRS)

Abdul-Aziz, A.; August, R.; Nagpal, V.

1993-01-01

Nonlinear finite-element structural analyses were performed on the first stage high-pressure fuel turbopump blade of the Space Shuttle Main Engine. The analyses examined the structural response and the dynamic characteristics at typical operating conditions. Single crystal material PWA-1480 was considered for the analyses. Structural response and the blade natural frequencies with respect to the crystal orientation were investigated. The analyses were conducted based on typical test stand engine cycle. Influence of combined thermal, aerodynamic, and centrifugal loadings was considered. Results obtained showed that the single crystal secondary orientation effects on the maximum principal stresses are not highly significant.

Engine Development Design Margins Briefing Charts

NASA Technical Reports Server (NTRS)

Bentz, Chuck

2006-01-01

New engines experience durability problems after entering service. The most prevalent and costly is the hot section, particularly the high-pressure turbine. The origin of durability problems can be traced back to: 1) the basic aero-mechanical design systems, assumptions, and design margins used by the engine designers, 2) the available materials systems, and 3) to a large extent, aggressive marketing in a highly competitive environment that pushes engine components beyond the demonstrated capability of the basic technology available for the hardware designs. Unfortunately the user must operate the engine in the service environment in order to learn the actual thrust loading and the time at max effort take-off conditions used in service are needed to determine the hot section life. Several hundred thousand hours of operational service will be required before the demonstrated reliability of a fleet of engines or the design deficiencies of the engine hot section parts can be determined. Also, it may take three to four engine shop visits for heavy maintenance on the gas path hardware to establish cost effective build standards. Spare parts drive the oerator's engine maintenance costs but spare parts also makes lots of money for the engine manufacturer during the service life of an engine. Unless competition prevails for follow-on engine buys, there is really no motivation for an OEM to spend internal money to improve parts durability and reduce earnings derived from a lucrative spare parts business. If the hot section life is below design goals or promised values, the OEM migh argue that the engine is being operated beyond its basic design intent. On the other hand, the airframer and the operator will continue to remind the OEM that his engine was selected based on a lot of promises to deliver spec thrust with little impact on engine service life if higher thrust is used intermittently. In the end, a standoff prevails and nothing gets fixed. This briefing will propose ways to hold competing engine manufacturers more accountable for engine hot section design margins during the entire Engine Development process as well as provide tools to assess the design temperature margins in the hot section parts of Service Engines.

Proceedings of the ISTVS (International Society for Terrain-Vehicle Systems) Workshop on Measurement and Evaluation of Tire Performance under Winter Conditions, Alta, Utah, 11-14 April 1983.

DTIC Science & Technology

1985-09-01

Transducers capable of measuring electro-hydraulic control system which fore-aft and vertical load on a driven controls the brake system to deactivate tire...power. * axle allows design of all load-carrying - System logic power. ENGINE I EXTERNAL COMPARTMENT COMPONENTS CAB Brake Levelin system I trans... brake con- The TWS DAS was designed to 1) pro- trol system . vide onboard data sampling and filtering, A simplified truck operational flow chart 2) make

Sustainability Metrics of a Small Scale Turbojet Engine

NASA Astrophysics Data System (ADS)

Ekici, Selcuk; Sohret, Yasin; Coban, Kahraman; Altuntas, Onder; Karakoc, T. Hikmet

2018-05-01

Over the last decade, sustainable energy consumption has attracted the attention of scientists and researchers. The current paper presents sustainability indicators of a small scale turbojet engine, operated on micro-aerial vehicles, for discussion of the sustainable development of the aviation industry from a different perspective. Experimental data was obtained from an engine at full power load and utilized to conduct an exergy-based sustainability analysis. Exergy efficiency, waste exergy ratio, recoverable exergy ratio, environmental effect factor, exergy destruction factor and exergetic sustainability index are evaluated as exergetic sustainability indicators of the turbojet engine under investigation in the current study. The exergy efficiency of the small scale turbojet engine is calculated as 27.25 % whereas the waste exergy ratio, the exergy destruction factor and the sustainability index of the engine are found to be 0.9756, 0.5466 and 0.2793, respectively.

An engineering evaluation of the Space Shuttle OMS engine after 5 orbital flights

NASA Technical Reports Server (NTRS)

David, D.

1983-01-01

Design features, performances on the first five flights, and condition of the Shuttle OMS engines are summarized. The engines were designed to provide a vacuum-fed 6000 lb of thrust and a 310 sec specific impulse, fueled by a combination of N2O4 and monomethylhydrazine (MMH) at a mixture ratio of 1.65. The design lifetime is 1000 starts and 15 hr of cumulative firing duration. The engine assembly is throat gimballed and features yaw actuators. No degradation of the hot components was observed during the first five flights, and the injector pattern maintained a uniform, enduring level of performance. An increase in the take-off loads have led to enhancing the wall thickness in the nozzle in affected areas. The engine is concluded to be performing to design specifications and is considered an operational system.

SPIKE-2: a Practical Stirling Engine for Kilowatt Level Solar Power

NASA Technical Reports Server (NTRS)

Beale, W. T.

1984-01-01

Recent advances in the art of free piston Stirling engine design make possible the production of 1-10kW free piston Stirling linear alternator engine, hermetically sealed, efficient, durable and simple in construction and operation. Power output is in the form of single or three phase 60 Hz. AC, or DC. The three phase capability is available from single machines without need of external conditioning. Engine voltage control regains set voltage within 5 cycles in response to any load change. The existing SPIKE-2 design has an engine alternator efficiency of 25% at 650 C heater wall temperature and a service life of over three years in solar service. The same system can be scaled over a range of at least 100 watts to 25kW.

Studies on biogas-fuelled compression ignition engine under dual fuel mode.

PubMed

Mahla, Sunil Kumar; Singla, Varun; Sandhu, Sarbjot Singh; Dhir, Amit

2018-04-01

Experimental investigation has been carried out to utilize biogas as an alternative source of energy in compression ignition (CI) engine under dual fuel operational mode. Biogas was inducted into the inlet manifold at different flow rates along with fresh air through inlet manifold and diesel was injected as a pilot fuel to initiate combustion under dual fuel mode. The engine performance and emission characteristics of dual fuel operational mode were analyzed at different biogas flow rates and compared with baseline conventional diesel fuel. Based upon the improved performance and lower emission characteristics under the dual fuel operation, the optimum flow rate of biogas was observed to be 2.2 kg/h. The lower brake thermal efficiency (BTE) and higher brake-specific energy consumption (BSEC) were noticed with biogas-diesel fuel under dual fuel mode when compared with neat diesel operation. Test results showed reduced NO x emissions and smoke opacity level in the exhaust tailpipe emissions. However, higher hydrocarbon (HC) and carbon monoxide (CO) emissions were noticed under dual fuel mode at entire engine loads when compared with baseline fossil petro-diesel. Hence, the use of low-cost gaseous fuel such as biogas would be an economically viable proposition to address the current and future problems of energy scarcity and associated environmental concerns.

Regulated and unregulated emissions from a diesel engine fueled with biodiesel and biodiesel blended with methanol

NASA Astrophysics Data System (ADS)

Cheung, C. S.; Zhu, Lei; Huang, Zhen

Experiments were carried out on a diesel engine operating on Euro V diesel fuel, pure biodiesel and biodiesel blended with methanol. The blended fuels contain 5%, 10% and 15% by volume of methanol. Experiments were conducted under five engine loads at a steady speed of 1800 rev min -1 to assess the performance and the emissions of the engine associated with the application of the different fuels. The results indicate an increase of brake specific fuel consumption and brake thermal efficiency when the diesel engine was operated with biodiesel and the blended fuels, compared with the diesel fuel. The blended fuels could lead to higher CO and HC emissions than biodiesel, higher CO emission but lower HC emission than the diesel fuel. There are simultaneous reductions of NO x and PM to a level below those of the diesel fuel. Regarding the unregulated emissions, compared with the diesel fuel, the blended fuels generate higher formaldehyde, acetaldehyde and unburned methanol emissions, lower 1,3-butadiene and benzene emissions, while the toluene and xylene emissions not significantly different.

Lessons Learned with Metallized Gelled Propellants

NASA Technical Reports Server (NTRS)

1996-01-01

During testing of metallized gelled propellants in a rocket engine, many changes had to be made to the normal test program for traditional liquid propellants. The lessons learned during the testing and the solutions for many of the new operational conditions posed with gelled fuels will help future programs run more smoothly. The major factors that influenced the success of the testing were propellant settling, piston-cylinder tank operation, control of self pressurization, capture of metal oxide particles, and a gelled-fuel protective layer. In these ongoing rocket combustion experiments at the NASA Lewis Research Center, metallized, gelled liquid propellants are used in a small modular engine that produces 30 to 40 lb of thrust. Traditional liquid RP-1 and gelled RP-1 with 0-, 5-, and 55-wt% loadings of aluminum are used with gaseous oxygen as the oxidizer. The figure compares the thrust chamber efficiencies of different engines.

Mission Evaluation Room Intelligent Diagnostic and Analysis System (MIDAS)

NASA Technical Reports Server (NTRS)

Pack, Ginger L.; Falgout, Jane; Barcio, Joseph; Shnurer, Steve; Wadsworth, David; Flores, Louis

1994-01-01

The role of Mission Evaluation Room (MER) engineers is to provide engineering support during Space Shuttle missions, for Space Shuttle systems. These engineers are concerned with ensuring that the systems for which they are responsible function reliably, and as intended. The MER is a central facility from which engineers may work, in fulfilling this obligation. Engineers participate in real-time monitoring of shuttle telemetry data and provide a variety of analyses associated with the operation of the shuttle. The Johnson Space Center's Automation and Robotics Division is working to transfer advances in intelligent systems technology to NASA's operational environment. Specifically, the MER Intelligent Diagnostic and Analysis System (MIDAS) project provides MER engineers with software to assist them with monitoring, filtering and analyzing Shuttle telemetry data, during and after Shuttle missions. MIDAS off-loads to computers and software, the tasks of data gathering, filtering, and analysis, and provides the engineers with information which is in a more concise and usable form needed to support decision making and engineering evaluation. Engineers are then able to concentrate on more difficult problems as they arise. This paper describes some, but not all of the applications that have been developed for MER engineers, under the MIDAS Project. The sampling described herewith was selected to show the range of tasks that engineers must perform for mission support, and to show the various levels of automation that have been applied to assist their efforts.

14 CFR 25.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the engine compressor from the turbine or from loss of the turbine blades are considered to be... § 25.367 Unsymmetrical loads due to engine failure. (a) The airplane must be designed for the unsymmetrical loads resulting from the failure of the critical engine. Turbopropeller airplanes must be designed...

14 CFR 25.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... the engine compressor from the turbine or from loss of the turbine blades are considered to be... § 25.367 Unsymmetrical loads due to engine failure. (a) The airplane must be designed for the unsymmetrical loads resulting from the failure of the critical engine. Turbopropeller airplanes must be designed...

14 CFR 25.367 - Unsymmetrical loads due to engine failure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... the engine compressor from the turbine or from loss of the turbine blades are considered to be... § 25.367 Unsymmetrical loads due to engine failure. (a) The airplane must be designed for the unsymmetrical loads resulting from the failure of the critical engine. Turbopropeller airplanes must be designed...

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 cooling requirements.

High Temperature Solid Lubricant Materials for Heavy Duty and Advanced Heat Engines

NASA Technical Reports Server (NTRS)

Dellacorte, C.; Wood, J. C.

1994-01-01

Advanced engine designs incorporate higher mechanical and thermal loading to achieve efficiency improvements. This approach often leads to higher operating temperatures of critical sliding elements (e.g. piston ring/cylinder wall contacts and valve guides) which compromise the use of conventional and even advanced synthetic liquid lubricants. For these applications solid lubricants must be considered. Several novel solid lubricant composites and coatings designated PS/PM200 have been employed to dry and marginally oil lubricated contacts in advanced heat engines. These applications include cylinder kits of heavy duty diesels, and high temperature Stirling engines, sidewall seals of rotary engines, and various exhaust valve and exhaust component applications. This paper describes the tribological and thermophysical properties of these tribomaterials and reviews the results of applying them to engine applications. Other potential tribological materials and applications are also discussed with particular emphasis on heavy duty and advanced heat engines.

A study on emission characteristics of an EFI engine with ethanol blended gasoline fuels

NASA Astrophysics Data System (ADS)

He, Bang-Quan; Wang, Jian-Xin; Hao, Ji-Ming; Yan, Xiao-Guang; Xiao, Jian-Hua

The effect of ethanol blended gasoline fuels on emissions and catalyst conversion efficiencies was investigated in a spark ignition engine with an electronic fuel injection (EFI) system. The addition of ethanol to gasoline fuel enhances the octane number of the blended fuels and changes distillation temperature. Ethanol can decrease engine-out regulated emissions. The fuel containing 30% ethanol by volume can drastically reduce engine-out total hydrocarbon emissions (THC) at operating conditions and engine-out THC, CO and NO x emissions at idle speed, but unburned ethanol and acetaldehyde emissions increase. Pt/Rh based three-way catalysts are effective in reducing acetaldehyde emissions, but the conversion of unburned ethanol is low. Tailpipe emissions of THC, CO and NO x have close relation to engine-out emissions, catalyst conversion efficiency, engine's speed and load, air/fuel equivalence ratio. Moreover, the blended fuels can decrease brake specific energy consumption.

Effects of Heat of Vaporization and Octane Sensitivity on Knock-Limited Spark Ignition Engine Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ratcliff, Matthew A; Burton, Jonathan L; Sindler, Petr

Knock-limited loads for a set of surrogate gasolines all having nominal 100 research octane number (RON), approximately 11 octane sensitivity (S), and a heat of vaporization (HOV) range of 390 to 595 kJ/kg at 25 degrees C were investigated. A single-cylinder spark-ignition engine derived from a General Motors Ecotec direct injection (DI) engine was used to perform load sweeps at a fixed intake air temperature (IAT) of 50 degrees C, as well as knock-limited load measurements across a range of IATs up to 90 degrees C. Both DI and pre-vaporized fuel (supplied by a fuel injector mounted far upstream ofmore » the intake valves and heated intake runner walls) experiments were performed to separate the chemical and thermal effects of the fuels' knock resistance. The DI load sweeps at 50 degrees C intake air temperature showed no effect of HOV on the knock-limited performance. The data suggest that HOV acts as a thermal contributor to S under the conditions studied. Measurement of knock-limited loads from the IAT sweeps for DI at late combustion phasing showed that a 40 vol% ethanol (E40) blend provided additional knock resistance at the highest temperatures, compared to a 20 vol% ethanol blend and hydrocarbon fuel with similar RON and S. Using the pre-vaporized fuel system, all the high S fuels produced nearly identical knock-limited loads at each temperature across the range of IATs studied. For these fuels RON ranged from 99.2 to 101.1 and S ranged from 9.4 to 12.2, with E40 having the lowest RON and highest S. The higher knock-limited loads for E40 at the highest IATs examined were consistent with the slightly higher S for this fuel, and the lower engine operating condition K values arising from use of this fuel. The study highlights how fuel HOV can affect the temperature at intake valve closing, and consequently the pressure-temperature history of the end gas leading to more negative values of K, thereby enhancing the effect of S on knock resistance.« less

Time-dependent constitutive modeling of drive belts—II. The effect of the shape of material retardation spectrum on the strain accumulation process

NASA Astrophysics Data System (ADS)

Zupančič, B.; Emri, I.

2009-11-01

This is the second paper in the series addressing the constitutive modeling of dynamically loaded elastomeric products such as power transmission belts. During the normal operation of such belts certain segments of the belt structure are loaded via tooth-like cyclical loading. When the time-dependent properties of the elastomeric material “match” the time-scale of the dynamic loading a strain accumulation (incrementation) process occurs. It was shown that the location of a critical rotation speed strongly depends on the distribution (shape) of the retardation spectrum, whereas the magnitude of the accumulated strain is governed by the strength of the corresponding spectrum lines. These interrelations are extremely non-linear. The strain accumulation process is most intensive at the beginning of the drive belt operation, and is less intensive for longer belts. The strain accumulation process is governed by the spectrum lines that are positioned within a certain region, which we call the Strain Accumulation Window (SAW). An SAW is always located to the right of the spectrum line, L i , at log ( ω λ i )=0, where ω is the operational angular velocity. The width of the SAW depends on the width of the material spectrum. Based on the following analysis a new designing criterion is proposed for use in engineering applications for selecting a proper material for general drive-belt operations.

Engine System Loads Analysis Compared to Hot-Fire Data

NASA Technical Reports Server (NTRS)

Frady, Gregory P.; Jennings, John M.; Mims, Katherine; Brunty, Joseph; Christensen, Eric R.; McConnaughey, Paul R. (Technical Monitor)

2002-01-01

Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the NASA MC-1 engine program, the focus was to reduce the cost-to-weight ratio. The techniques for structural dynamics analysis practices, were tailored in this program to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of MC-1 load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are important during the design and integration of a new engine system. During the final stages of development, it is important to verify the results of an engine system model to determine the validity of the results. During the final stages of the MC-1 program, hot-fire test results were obtained and compared to the structural design loads calculated by the engine system model. These comparisons are presented in this paper.

Experimental analysis of IMEP in a rotary combustion engine

NASA Technical Reports Server (NTRS)

Schock, H. J.; Rice, W. J.; Meng, P. R.

1981-01-01

A real time indicated mean effective pressure measurement system is described which is used to judge proposed improvements in cycle efficiency of a rotary combustion engine. This is the first self-contained instrument that is capable of making real time measurements of IMEP in a rotary engine. Previous methods used require data recording and later processing using a digital computer. The unique features of this instrumentation include its ability to measure IMEP on a cycle by cycle, real time basis and the elimination of the need to differentiate volume function in real time. Measurements at two engine speeds (2000 and 3000 rpm) and a full range of loads are presented, although the instrument was designed to operate to speeds of 9000 rpm.

Simulating the Impact of Premixed Charge Compression Ignition on Light-Duty Diesel Fuel Economy and Emissions of Particulates and NOx

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Zhiming; Daw, C Stuart; Wagner, Robert M

2013-01-01

We utilize the Powertrain Systems Analysis Toolkit (PSAT) combined with transient engine and aftertreatment component models implemented in Matlab/Simulink to simulate the effect of premixed charge compression ignition (PCCI) on the fuel economy and emissions of light-duty diesel-powered conventional and hybrid electric vehicles (HEVs). Our simulated engine is capable of both conventional diesel combustion (CDC) and premixed charge compression ignition (PCCI) over real transient driving cycles. Our simulated aftertreatment train consists of a diesel oxidation catalyst (DOC), lean NOx trap (LNT), and catalyzed diesel particulate filter (DPF). The results demonstrate that, in the simulated conventional vehicle, PCCI can significantly reducemore » fuel consumption and emissions by reducing the need for LNT and DPF regeneration. However, the opportunity for PCCI operation in the simulated HEV is limited because the engine typically experiences higher loads and multiple stop-start transients that are outside the allowable PCCI operating range. Thus developing ways of extending the PCCI operating range combined with improved control strategies for engine and emissions control management will be especially important for realizing the potential benefits of PCCI in HEVs.« less

Geographic Visualization of Power-Grid Dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sukumar, Sreenivas R.

2015-06-18

The visualization enables the simulation analyst to see changes in the frequency through time and space. With this technology, the analyst has a bird's eye view of the frequency at loads and generators as the simulated power system responds to the loss of a generator, spikes in load, and other contingencies. The significance of a contingency to the operation of an electrical power system depends critically on how the resulting tansients evolve in time and space. Consequently, these dynamic events can only be understood when seen in their proper geographic context. this understanding is indispensable to engineers working on themore » next generation of distributed sensing and control systems for the smart grid. By making possible a natural and intuitive presentation of dynamic behavior, our new visualization technology is a situational-awareness tool for power-system engineers.« less

An integrated eVoucher mechanism for flexible loads in real-time retail electricity market

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Tao; Pourbabak, Hajir; Liang, Zheming

This study proposes an innovative economic and engineering coupled framework to encourage typical flexible loads or load aggregators, such as parking lots with high penetration of electric vehicles, to participate directly in the real-time retail electricity market based on an integrated eVoucher program. The integrated eVoucher program entails demand side management, either in the positive or negative direction, following a popular customer-centric design principle. It provides the extra economic benefit to end-users and reduces the risk associated with the wholesale electricity market for electric distribution companies (EDCs), meanwhile improving the potential resilience of the distribution networks with consideration for frequencymore » deviations. When implemented, the eVoucher program allows typical flexible loads, such as electric vehicle parking lots, to adjust their demand and consumption behavior according to financial incentives from an EDC. A distribution system operator (DSO) works as a third party to hasten negotiations between such parking lots and EDCs, as well as the price clearing process. Eventually, both electricity retailers and power system operators will benefit from the active participation of the flexible loads and energy customers.« less

An integrated eVoucher mechanism for flexible loads in real-time retail electricity market

DOE PAGES

Chen, Tao; Pourbabak, Hajir; Liang, Zheming; ...

2017-01-26

This study proposes an innovative economic and engineering coupled framework to encourage typical flexible loads or load aggregators, such as parking lots with high penetration of electric vehicles, to participate directly in the real-time retail electricity market based on an integrated eVoucher program. The integrated eVoucher program entails demand side management, either in the positive or negative direction, following a popular customer-centric design principle. It provides the extra economic benefit to end-users and reduces the risk associated with the wholesale electricity market for electric distribution companies (EDCs), meanwhile improving the potential resilience of the distribution networks with consideration for frequencymore » deviations. When implemented, the eVoucher program allows typical flexible loads, such as electric vehicle parking lots, to adjust their demand and consumption behavior according to financial incentives from an EDC. A distribution system operator (DSO) works as a third party to hasten negotiations between such parking lots and EDCs, as well as the price clearing process. Eventually, both electricity retailers and power system operators will benefit from the active participation of the flexible loads and energy customers.« less

Distortion and regulation characterization of a Mapham inverter

NASA Technical Reports Server (NTRS)

Sundberg, Richard C.; Brush, Andrew S.; Button, Robert M.; Patterson, Alexander G.

1989-01-01

Output-voltage total harmonic distortion (THD) of a 20-kHz, 6-kVA Mapham resonant inverter is characterized as a function of its switching-to-resonant frequency ratio, f(s)/f(r), using the EASY5 Engineering Analysis System. EASY5 circuit simulation results are compared with hardware test results to verify the accuracy of the simulations. The effects of load on the THD versus f(s)/f(r) is investigated for resistive, leading, and lagging power factor load impedances. The effect of the series output capacitor on the Mapham inverter output-voltage distortion and inherent load regulation is characterized under loads of various power factors and magnitudes. An optimum series capacitor value which improves the inherent load regulation to better than 3 percent is identified. The optimum series capacitor value is different from the value predicted from a modeled frequency domain analysis. An explanation is proposed which takes into account the conduction overlap in the inductor pairs during steady-state inverter operation, which decreases the effective inductance of a Mapham inverter. A fault protection and current limit method is discussed which allows the Mapham inverter to operate into a short circuit, even when the inverter resonant circuit becomes overdamped.

Distortion and regulation characterization of a Mapham inverter

NASA Technical Reports Server (NTRS)

Sundberg, Richard C.; Brush, Andrew S.; Button, Robert M.; Patterson, Alexander G.

1989-01-01

Output voltage Total Harmonic Distortion (THD) of a 20kHz, 6kVA Mapham resonant inverter is characterized as a function of its switching-to-resonant frequency ratio, f sub s/f sub r, using the EASY5 engineering analysis system. EASY5 circuit simulation results are compared with hardware test results to verify the accuracy of the simulations. The effects of load on the THD versus f sub s/f sub r ratio is investigated for resistive, leading, and lagging power factor load impedances. The effect of the series output capacitor on the Mapham inverter output voltage distortion and inherent load regulation is characterized under loads of various power factors and magnitudes. An optimum series capacitor value which improves the inherent load regulation to better than 3 percent is identified. The optimum series capacitor value is different than the value predicted from a modeled frequency domain analysis. An explanation is proposed which takes into account the conduction overlap in the inductor pairs during steady-state inverter operation, which decreases the effective inductance of a Mapham inverter. A fault protection and current limit method is discussed which allows the Mapham inverter to operate into a short circuit, even when the inverter resonant circuit becomes overdamped.

Performance deterioration due to acceptance testing and flight loads; JT90 jet engine diagnostic program

NASA Technical Reports Server (NTRS)

Olsson, W. J.

1982-01-01

The results of a flight loads test of the JT9D-7 engine are presented. The goals of this test program were to: measure aerodynamic and inertia loads on the engine during flight, explore the effects of airplane gross weight and typical maneuvers on these flight loads, simultaneously measure the changes in engine running clearances and performance resulting from the maneuvers, make refinements of engine performance deterioration prediction models based on analytical results of the tests, and make recommendations to improve propulsion system performance retention. The test program included a typical production airplane acceptance test plus additional flights and maneuvers to encompass the range of flight loads in revenue service. The test results indicated that aerodynamic loads, primarily at take-off, were the major cause of rub-indicated that aerodynamic loads, primarily at take-off, were the major cause of rub-induced deterioration in the cold sectin of the engine. Differential thermal expansion between rotating and static parts plus aerodynamic loads combined to cause blade-to-seal rubs in the turbine.

Calculation of Dynamic Loads Due to Random Vibration Environments in Rocket Engine Systems

NASA Technical Reports Server (NTRS)

Christensen, Eric R.; Brown, Andrew M.; Frady, Greg P.

2007-01-01

An important part of rocket engine design is the calculation of random dynamic loads resulting from internal engine "self-induced" sources. These loads are random in nature and can greatly influence the weight of many engine components. Several methodologies for calculating random loads are discussed and then compared to test results using a dynamic testbed consisting of a 60K thrust engine. The engine was tested in a free-free condition with known random force inputs from shakers attached to three locations near the main noise sources on the engine. Accelerations and strains were measured at several critical locations on the engines and then compared to the analytical results using two different random response methodologies.

Reactivity-controlled compression ignition drive cycle emissions and fuel economy estimations using vehicle system simulations

DOE PAGES

Curran, Scott J.; Gao, Zhiming; Wagner, Robert M.

2014-12-22

In-cylinder blending of gasoline and diesel to achieve reactivity-controlled compression ignition has been shown to reduce NO X and soot emissions while maintaining or improving brake thermal efficiency as compared with conventional diesel combustion. The reactivity-controlled compression ignition concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load, allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. In this paper, a multi-mode reactivity-controlled compression ignition strategy is employed where the engine switches from reactivity-controlled compression ignition to conventional diesel combustionmore » when speed and load demand are outside of the experimentally determined reactivity-controlled compression ignition range. The potential for reactivity-controlled compression ignition to reduce drive cycle fuel economy and emissions is not clearly understood and is explored here by simulating the fuel economy and emissions for a multi-mode reactivity-controlled compression ignition–enabled vehicle operating over a variety of US drive cycles using experimental engine maps for multi-mode reactivity-controlled compression ignition, conventional diesel combustion, and a 2009 port-fuel injected gasoline engine. Drive cycle simulations are completed assuming a conventional mid-size passenger vehicle with an automatic transmission. Multi-mode reactivity-controlled compression ignition fuel economy simulation results are compared with the same vehicle powered by a representative 2009 port-fuel injected gasoline engine over multiple drive cycles. Finally, engine-out drive cycle emissions are compared with conventional diesel combustion, and observations regarding relative gasoline and diesel tank sizes needed for the various drive cycles are also summarized.« less

An LPV Adaptive Observer for Updating a Map Applied to an MAF Sensor in a Diesel Engine.

PubMed

Liu, Zhiyuan; Wang, Changhui

2015-10-23

In this paper, a new method for mass air flow (MAF) sensor error compensation and an online updating error map (or lookup table) due to installation and aging in a diesel engine is developed. Since the MAF sensor error is dependent on the engine operating point, the error model is represented as a two-dimensional (2D) map with two inputs, fuel mass injection quantity and engine speed. Meanwhile, the 2D map representing the MAF sensor error is described as a piecewise bilinear interpolation model, which can be written as a dot product between the regression vector and parameter vector using a membership function. With the combination of the 2D map regression model and the diesel engine air path system, an LPV adaptive observer with low computational load is designed to estimate states and parameters jointly. The convergence of the proposed algorithm is proven under the conditions of persistent excitation and given inequalities. The observer is validated against the simulation data from engine software enDYNA provided by Tesis. The results demonstrate that the operating point-dependent error of the MAF sensor can be approximated acceptably by the 2D map from the proposed method.

Analysis of high load dampers

NASA Technical Reports Server (NTRS)

Bhat, S. T.; Buono, D. F.; Hibner, D. H.

1981-01-01

High load damping requirements for modern jet engines are discussed. The design of damping systems which could satisfy these requirements is also discusseed. In order to evaluate high load damping requirements, engines in three major classes were studied; large transport engines, small general aviation engines, and military engines. Four damper concepts applicable to these engines were evaluated; multi-ring, cartridge, curved beam, and viscous/friction. The most promising damper concept was selected for each engine and performance was assessed relative to conventional dampers and in light of projected damping requirements for advanced jet engines.

78 FR 31851 - Harmonization of Airworthiness Standards-Gust and Maneuver Load Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-28

... airplanes equipped with wing-mounted engines; revise the engine torque loads criteria; add an engine failure... equipped with wing-mounted engines. Following an accident in which an airplane shed a large wing- mounted...-93-137, November 15, 1993). This recommendation was specifically aimed at gust loads on wing-mounted...

Modeling and Simulation of a Free-Piston Engine with Electrical Generator Using HCCI Combustion

NASA Astrophysics Data System (ADS)

Alrbai, Mohammad

Free-piston engines have the potential to challenge the conventional crankshaft engines by their design simplicity and higher operational efficiency. Many studies have been performed to overcome the limitations of the free-piston devices especially the stability and control issues. The investigations within the presented dissertation aim to satisfy many objectives by employing the approach of chemical kinetics to present the combustion process in the free-piston engine. This approach in addition to its advanced accuracy over the empirical methods, it has many other features like the ability to analyze the engine emissions. The effect of the heat release rate (HRR) on the engine performance is considered as the main objective. Understanding the relation between the HRR and the piston dynamics helps in enhancing the system efficiency and identifying the parameters that affect the overall performance. The dissertation covers some other objectives that belongs to the combustion phasing. Exhaust gas recirculation (EGR), equivalence ratio and the intake temperature represent the main combustion parameters, which have been discussed in this dissertation. To obtain the stability in system performance, the model requires a proper controller to simulate the operation and manage the different system parameters; for this purpose, different controlling techniques have been employed. In addition, the dissertation considers some other topics like engine emissions, fuels and fuels mechanisms. The model of the study describes the processes within a single cylinder, two stroke engine, which includes springs to support higher frequencies, reduce cyclic variations and sustain the engine compression ratio. An electrical generator presents the engine load; the generator supports different load profiles and play the key role in controlling the system. The 1st law of thermodynamics and Newton's 2nd law are applied to couple the piston dynamics with the engine thermodynamics. The model governing equations represent a single zone perfectly stirred reactor (PSR) which contain a perfect mixing ideal gas mixture. The chemical kinetics approach is applied using Cantera/ MATLABRTM toolbox, which presents the combustion process. In this research, a homogenous charge compression ignition (HCCI) at different operational conditions is used. HCCI engines have high efficiencies and low emissions and can work within a wide range of fuels. The results have been presented in a multi-cycle simulation and a parametric study forms. In the case of the multi-cycle simulation, a 100 cycles of the engine operation have been simulated. The overall work that is delivered to the electrical generator presents 47% of the total fuel energy. The model indicates an average frequency of 125 Hz along the operational cycles. In order to eliminate the cyclic variations and ensure a continuous operation, a proportional derivative (PD) controller has been employed. The controller adjusts the generator load in order to minimize the difference between the bottom dead center (BDC) locations along the operation cycles. The PD controller shows weakness in achieving the full steady state operation, for this purpose; a proportional integral (PI) controller has been implemented. The PI controller seeks to achieve a specific compression ratio. The results show that; the PI controller indicates unique behavior after 15 cycles of operation where the model ended to fluctuate between two compression ratios only. The complex relation between the thermodynamics and the dynamics of the engine is the greatest challenge in examining the effectiveness of the PI controller. In the parametric investigations, EGR examinations show that NOx emission is reduced to less than the half, as 30 % of EGR is used; this occurs due to the EGR thermal and dilution effects, which cause significant drop in the peak bulk temperature and CO emissions as well. Under the applied conditions, EGR has the ability to raise the work output ratio by increasing the engine compression ratio. The examination of the EGR temperature on the engine performance indicates that cooled EGR charges have the advantage over the hot EGR mixtures on enhancing the work output ratio. At the same time, EGR temperature affects the NOx formation by speeding its instantaneous reactions rate. The dissertation includes a study of the effect of the intake temperature and the equivalence ratio (φ) as well. The increasing in the intake temperature reduce the time needed for ignition, but leads to a reduction in the work output ratio at the same time. Such results can help in studying high knock resistance fuels where ignition delay is a matter. In the case of the equivalence ratio, lean mixtures show efficiencies that exceed 50% compared to those at the stoichiometric conditions. In the case of the ultra-lean (φ<0.5) combustion, the results show that the NOx emission is with the minimal levels as well as the CO and the unburned hydrocarbons (UHC) emissions. Sensitivity analysis to the chemical kinetic mechanism for the fuel combustion has been presented also in the dissertation. Many mechanisms for different fuels have been investigated, for example; a modified mechanism for Methane that includes 36 species and 222 reactions has been compared with the full GRI 3.0 mechanism (53 species and 325 reactions). The results of this comparison indicate that the modified mechanism has the potential to replace the full one in some cases like in demonstrating the engine operation, but not in the engine emissions analysis.

Diesel emission reduction using internal exhaust gas recirculation

DOEpatents

He, Xin [Denver, CO; Durrett, Russell P [Bloomfield Hills, MI

2012-01-24

A method for controlling combustion in a direct-injection diesel engine includes monitoring a crankshaft rotational position of a cylinder of the engine, monitoring an engine load, determining an intake stroke within the cylinder based upon the crankshaft rotational position, and when the engine load is less than a threshold engine load, opening an exhaust valve for the cylinder during a portion of the intake stroke.

A mobile test facility based on a magnetic cumulative generator to study the stability of the power plants under impact of lightning currents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shurupov, A. V.; Zavalova, V. E., E-mail: zavalova@fites.ru; Kozlov, A. V.

The report presents the results of the development and field testing of a mobile test facility based on a helical magnetic cumulative generator (MCGTF). The system is designed for full-scale modeling of lightning currents to study the safety of power plants of any type, including nuclear power plants. Advanced technologies of high-energy physics for solving both engineering and applied problems underlie this pilot project. The energy from the magnetic cumulative generator (MCG) is transferred to a high-impedance load with high efficiency of more than 50% using pulse transformer coupling. Modeling of the dynamics of the MEG that operates in amore » circuit with lumped parameters allows one to apply the law of inductance output during operation of the MCG, thus providing the required front of the current pulse in the load without using any switches. The results of field testing of the MCGTF are presented for both the ground loop and the model load. The ground loop generates a load resistance of 2–4 Ω. In the tests, the ohmic resistance of the model load is 10 Ω. It is shown that the current pulse parameters recorded in the resistive-inductive load are close to the calculated values.« less

Predicting the Effects of Powder Feeding Rates on Particle Impact Conditions and Cold Spray Deposited Coatings

NASA Astrophysics Data System (ADS)

Ozdemir, Ozan C.; Widener, Christian A.; Carter, Michael J.; Johnson, Kyle W.

2017-10-01

As the industrial application of the cold spray technology grows, the need to optimize both the cost and the quality of the process grows with it. Parameter selection techniques available today require the use of a coupled system of equations to be solved to involve the losses due to particle loading in the gas stream. Such analyses cause a significant increase in the computational time in comparison with calculations with isentropic flow assumptions. In cold spray operations, engineers and operators may, therefore, neglect the effects of particle loading to simplify the multiparameter optimization process. In this study, two-way coupled (particle-fluid) quasi-one-dimensional fluid dynamics simulations are used to test the particle loading effects under many potential cold spray scenarios. Output of the simulations is statistically analyzed to build regression models that estimate the changes in particle impact velocity and temperature due to particle loading. This approach eases particle loading optimization for more complete analysis on deposition cost and time. The model was validated both numerically and experimentally. Further numerical analyses were completed to test the particle loading capacity and limitations of a nozzle with a commonly used throat size. Additional experimentation helped document the physical limitations to high-rate deposition.

Experimental investigations of the hydrogen addition effects on diesel engine performance

NASA Astrophysics Data System (ADS)

Mirica, I.; Pana, C.; Negurescu, N.; Cernat, A.; Nutu, C.

2016-08-01

In the global content regarding the impact on the environmental of the gases emissions resulted from the fossil fuels combustion, an interest aspect discussed on the 21st Session of the Conference of the Parties from the 2015 Paris Climate Conference and the gradual diminution of the worldwide oil reserves contribute to the necessity of searching of alternative energy from durable and renewable resources. At the use of hydrogen as addition in air to diesel engine, the level of CO, HC and smoke from the exhaust gases will decrease due to the improvement of the combustion process. At low and medium partial loads and low hydrogen energetic ratios used the NOX emission level can decrease comparative to classic diesel engine. The hydrogen use as fuel for diesel engine leads to the improving of the energetic and emissions performance of the engine due to combustion improvement and reduction of carbon content. The paper presents, in a comparative way, results of the experimental researches carried on a truck compression ignition engine fuelled with diesel fuel and with hydrogen diesel fuel and hydrogen as addition in air at different engine operation regimes. The results obtained during experimental investigations show better energetic and pollution performance of the engine fuelled with hydrogen as addition in air comparative to classic engine. The influences of hydrogen addition on engine operation are shown.

Dual fuel diesel engine operation using LPG

NASA Astrophysics Data System (ADS)

Mirica, I.; Pana, C.; Negurescu, N.; Cernat, Al; Nutu, N. C.

2016-08-01

Diesel engine fuelling with LPG represents a good solution to reduce the pollutant emissions and to improve its energetic performances. The high autoignition endurance of LPG requires specialized fuelling methods. From all possible LPG fuelling methods the authors chose the diesel-gas method because of the following reasons: is easy to be implemented even at already in use engines; the engine does not need important modifications; the LPG-air mixture has a high homogeneity with favorable influences over the combustion efficiency and over the level of the pollutant emissions, especially on the nitrogen oxides emissions. This paper presents results of the theoretical and experimental investigations on operation of a LPG fuelled heavy duty diesel engine at two operating regimens, 40% and 55%. For 55% engine load is also presented the exhaust gas recirculation influence on the pollutant emission level. Was determined the influence of the diesel fuel with LPG substitution ratio on the combustion parameters (rate of heat released, combustion duration, maximum pressure, maximum pressure rise rate), on the energetic parameters (indicate mean effective pressure, effective efficiency, energetic specific fuel consumption) and on the pollutant emissions level. Therefore with increasing substitute ratio of the diesel fuel with LPG are obtained the following results: the increase of the engine efficiency, the decrease of the specific energetic consumption, the increase of the maximum pressure and of the maximum pressure rise rate (considered as criteria to establish the optimum substitute ratio), the accentuated reduction of the nitrogen oxides emissions level.

Transport Refrigeration Technician: Apprenticeship Course Outline. Apprenticeship and Industry Training. 4112

ERIC Educational Resources Information Center

Alberta Advanced Education and Technology, 2012

2012-01-01

The graduate of the Transport Refrigeration Technician apprenticeship program is a certified journeyperson who will be able: (1) to diagnose repair, maintain and operate transport refrigeration equipment used to heat or cool the load as well as of diesel engines, APUs and other prime movers; (2) to use tools and equipment in order to carry out…

Solar Hot Water for Motor Inn--Texas City, Texas

NASA Technical Reports Server (NTRS)

1982-01-01

Final report describes solar domestic-hot-water heater installation at LaQuinta Motor Inn, Texas City, Texas which furnished 63% of total hot-water load of new 98-unit inn. Report presents a description of system, drawings and photographs of collectors, operations and maintenance instructions, manufacturers' specifications for pumps, and an engineer's report on performance.

Control of harmful hydrocarbon species in the exhaust of modern advanced GDI engines

NASA Astrophysics Data System (ADS)

Hasan, A. O.; Abu-jrai, A.; Turner, D.; Tsolakis, A.; Xu, H. M.; Golunski, S. E.; Herreros, J. M.

2016-03-01

A qualitative and quantitative analysis of toxic but currently non-regulated hydrocarbon compounds ranging from C5-C11, before and after a zoned three-way catalytic converter (TWC) in a modern gasoline direct injection (GDI) engine has been studied using gas chromatography-mass spectrometry (GC-MS). The GDI engine has been operated under conventional and advanced combustion modes, which result in better fuel economy and reduced levels of NOx with respect to standard SI operation. However, these fuel-efficient conditions are more challenging for the operation of a conventional TWC, and could lead to higher level of emissions released to the environment. Lean combustion leads to the reduction in pumping losses, fuel consumption and in-cylinder emission formation rates. However, lean HCCI will lead to high levels of unburnt HCs while the presence of oxygen will lower the TWC efficiency for NOx control. The effect on the catalytic conversion of the hydrocarbon species of the addition of hydrogen upstream the catalyst has been also investigated. The highest hydrocarbon engine-out emissions were produced for HCCI engine operation at low engine load operation. The catalyst was able to remove most of the hydrocarbon species to low levels (below the permissible exposure limits) for standard and most of the advanced combustion modes, except for naphthalene (classified as possibly carcinogenic to humans by the International Agency for Research on Cancer) and methyl-naphthalene (which has the potential to cause lung damage). However, when hydrogen was added upstream of the catalyst, the catalyst conversion efficiency in reducing methyl-naphthalene and naphthalene was increased by approximately 21%. This results in simultaneous fuel economy and environmental benefits from the effective combination of advanced combustion and novel aftertreatment systems.

M.E.366-J embodiment design project: Portable foot restraint

NASA Technical Reports Server (NTRS)

Heaton, Randall; Meyer, Eikar; Schmidt, Davey; Enders, Kevin

1994-01-01

During space shuttle operations, astronauts require support to carry out tasks in the weightless environment. In the past, portable foot restraints (PFR) with orientations adjustable in pitch, roll, and yaw provided this support for payload bay operations. These foot restraints, however, were designed for specific tasks with a load limit of 111.2 Newtons. Since the original design, new applications for foot restraints have been identified. New designs for the foot restraints have been created to boost the operational work load to 444.8 Newtons and decrease setup times. What remains to be designed is an interface between the restraint system and the extravehicular mobility unit (EMU) boots. NASA provided a proposed locking device involving a spring-loaded mechanism. This locking mechanism must withstand loads of 1334.4 Newtons in any direction and weigh less than 222.4 Newtons. This paper develops an embodiment design for the interface between the PFR and the EMU boots. This involves design of the locking mechanism and a removable cleat that allows the boot to interface with this mechanism. The design team used the Paul Beitz engineering methodology to present the systematic development, structural analysis, and production considerations of the embodiment design. This methodology provides a basis for understanding the justification behind the decisions made in the design.

Using Advanced Tabu Search Approaches to Perform Enhanced Air Mobility Command Operational Airlift Analyses

DTIC Science & Technology

2009-02-28

2, No. 2, 2007, pp. 156-172. 21. Lambert, G.,J.W. Barnes, and D. Van Veldhuizen ,, "A Tabu Search Approach to the Strategic Airlift Problem...Industrial Engineering, accepted, to appear 2009, pp 1 -86, published by Taylor and Francis/CRC Press. 27. Roesener, A., J. W. Barnes, J. Moore, D. Van ... Veldhuizen , "An Advanced Tabu Search Approach To The Static Airlift Loading Problem," Military Operations Research, 2007, (in second review). 28. Burks

Trace Contaminant Control During the International Space Station's On-Orbit Assembly and Outfitting

NASA Technical Reports Server (NTRS)

Perry, J. L.

2017-01-01

Achieving acceptable cabin air quality must balance competing elements during spacecraft design, assembly, ground processing, and flight operations. Among the elements that contribute to the trace chemical contaminant load and, therefore, the cabin air quality aboard crewed spacecraft are the vehicle configuration, crew size and activities, mission duration and objectives, materials selection, and vehicle manufacturing and preflight ground processing methods. Trace chemical contaminants produced from pervasive sources such as equipment offgassing, human metabolism, and cleaning fluids during preflight ground processing present challenges to maintaining acceptable cabin air quality. To address these challenges, both passive and active contamination control techniques are used during a spacecraft's design, manufacturing, preflight preparation, and operational phases. Passive contamination control methods seek to minimize the equipment offgassing load by selecting materials, manufacturing processes, preflight preparation processes, and in-flight operations that have low chemical offgassing characteristics. Passive methods can be employed across the spacecraft's entire life cycle from conceptual design through flight operations. However, because the passive contamination control techniques cannot fully eliminate the contaminant load, active contamination control equipment must be deployed aboard the spacecraft to purify and revitalize the cabin atmosphere during in-flight operations. Verifying that the passive contamination control techniques have successfully maintained the total trace contaminant load within the active contamination control equipment's capabilities occurs late in the preflight preparation stages. This verification consists of subjecting the spacecraft to an offgassing test to determine the trace contaminant load. This load is then assessed versus the active contamination control equipment's capabilities via trace contaminant control (TCC) engineering analysis. During the International Space Station's (ISS's) on-orbit assembly and outfitting, a series of engineering analyses were conducted to evaluate how effective the passive TCC methods were relative to providing adequate operational margin for the active TCC equipment's capabilities aboard the ISS. These analyses were based on habitable module and cargo vehicle offgassing test results. The offgassing test for a fully assembled module or cargo vehicle is an important preflight spacecraft evaluation method that has been used successfully during all crewed spacecraft programs to provide insight into how effectively the passive contamination control methods limit the equipment offgassing component of the overall trace contaminant generation load. The progression of TCC assessments beginning in 1998 with the ISS's first habitable element launch and continuing through the final pressurized element's arrival in 2010 are presented. Early cargo vehicle flight assessments between 2008 and 2011 are also presented as well as a discussion on predictive methods for assessing cargo via a purely analytical technique. The technical approach for TCC employed during this 13-year period successfully maintained the cabin atmospheric quality within specified parameters during the technically challenging ISS assembly and outfitting stages. The following narrative provides details on the important role of spacecraft offgassing testing, trace contaminant performance requirements, and flight rules for achieving the ultimate result-a cabin environment that enables people to live and work safely in space.

Application of controllable pulverized-coal rich/lean combustion technology at the Hebi Wanhe Power Generation Co. Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jianzhong, L.; Xiang, Z.; Junhu, Z.

1999-07-01

The No.2 unit (670/H, 200MW) at Hebi Wanhe Power Generation C o. Ltd., was put into use in 1992. This is a coal-fired boiler with tangential fired method. The design coal is Hebi lean coal. To stabilize the combustion without oil at low load, eight original designed burners placed to No. 2 and 3 level on the No.2 boiler were replaced with the controllable pulverized rich/lean ones developed by the Institute for Thermal Power Engineering (ITPE) of Zhejiang University. The practice of successive operation shows that stable combustion can be achieved at 50% load without support oil, even at 45%more » load. The combustible matter in fly ash decreased to 1.12% and 1.17% from 1.83% and 1.32%, respectively at full load (200MW) and half load (100MW). The application has obvious economic benefits.« less

Load Capacity Estimation of Foil Air Journal Bearings for Oil-Free Turbomachinery Applications

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Valco, Mark J.

2000-01-01

This paper introduces a simple "Rule of Thumb" (ROT) method to estimate the load capacity of foil air journal bearings, which are self-acting compliant-surface hydrodynamic bearings being considered for Oil-Free turbo-machinery applications such as gas turbine engines. The ROT is based on first principles and data available in the literature and it relates bearing load capacity to the bearing size and speed through an empirically based load capacity coefficient, D. It is shown that load capacity is a linear function of bearing surface velocity and bearing projected area. Furthermore, it was found that the load capacity coefficient, D, is related to the design features of the bearing compliant members and operating conditions (speed and ambient temperature). Early bearing designs with basic or "first generation" compliant support elements have relatively low load capacity. More advanced bearings, in which the compliance of the support structure is tailored, have load capacities up to five times those of simpler designs. The ROT enables simplified load capacity estimation for foil air journal bearings and can guide development of new Oil-Free turbomachinery systems.

Testing of the Engineering Model Electrical Power Control Unit for the Fluids and Combustion Facility

NASA Technical Reports Server (NTRS)

Kimnach, Greg L.; Lebron, Ramon C.; Fox, David A.

1999-01-01

The John H. Glenn Research Center at Lewis Field (GRC) in Cleveland, OH and the Sundstrand Corporation in Rockford, IL have designed and developed an Engineering Model (EM) Electrical Power Control Unit (EPCU) for the Fluids Combustion Facility, (FCF) experiments to be flown on the International Space Station (ISS). The EPCU will be used as the power interface to the ISS power distribution system for the FCF's space experiments'test and telemetry hardware. Furthermore. it is proposed to be the common power interface for all experiments. The EPCU is a three kilowatt 12OVdc-to-28Vdc converter utilizing three independent Power Converter Units (PCUs), each rated at 1kWe (36Adc @ 28Vdc) which are paralleled and synchronized. Each converter may be fed from one of two ISS power channels. The 28Vdc loads are connected to the EPCU output via 48 solid-state and current-limiting switches, rated at 4Adc each. These switches may be paralleled to supply any given load up to the 108Adc normal operational limit of the paralleled converters. The EPCU was designed in this manner to maximize allocated-power utilization. to shed loads autonomously, to provide fault tolerance. and to provide a flexible power converter and control module to meet various ISS load demands. Tests of the EPCU in the Power Systems Facility testbed at GRC reveal that the overall converted-power efficiency, is approximately 89% with a nominal-input voltage of 12OVdc and a total load in the range of 4O% to 110% rated 28Vdc load. (The PCUs alone have an efficiency of approximately 94.5%). Furthermore, the EM unit passed all flight-qualification level (and beyond) vibration tests, passed ISS EMI (conducted, radiated. and susceptibility) requirements. successfully operated for extended periods in a thermal/vacuum chamber, was integrated with a proto-flight experiment and passed all stability and functional requirements.

Structural Life and Reliability Metrics: Benchmarking and Verification of Probabilistic Life Prediction Codes

NASA Technical Reports Server (NTRS)

Litt, Jonathan S.; Soditus, Sherry; Hendricks, Robert C.; Zaretsky, Erwin V.

2002-01-01

Over the past two decades there has been considerable effort by NASA Glenn and others to develop probabilistic codes to predict with reasonable engineering certainty the life and reliability of critical components in rotating machinery and, more specifically, in the rotating sections of airbreathing and rocket engines. These codes have, to a very limited extent, been verified with relatively small bench rig type specimens under uniaxial loading. Because of the small and very narrow database the acceptance of these codes within the aerospace community has been limited. An alternate approach to generating statistically significant data under complex loading and environments simulating aircraft and rocket engine conditions is to obtain, catalog and statistically analyze actual field data. End users of the engines, such as commercial airlines and the military, record and store operational and maintenance information. This presentation describes a cooperative program between the NASA GRC, United Airlines, USAF Wright Laboratory, U.S. Army Research Laboratory and Australian Aeronautical & Maritime Research Laboratory to obtain and analyze these airline data for selected components such as blades, disks and combustors. These airline data will be used to benchmark and compare existing life prediction codes.

Emission rates of particulate matter and elemental and organic carbon from in-use diesel engines.

PubMed

Shah, Sandip D; Cocker, David R; Miller, J Wayne; Norbeck, Joseph M

2004-05-01

Elemental carbon (EC), organic carbon (OC), and particulate matter (PM) emission rates are reported for a number of heavy heavy-duty diesel trucks (HHDDTs) and back-up generators (BUGs) operating under real-world conditions. Emission rates were determined using a unique mobile emissions laboratory (MEL) equipped with a total capture full-scale dilution tunnel connected directly to the diesel engine via a snorkel. This paper shows that PM, EC, and OC emission rates are strongly dependent on the mode of vehicle operation; highway, arterial, congested, and idling conditions were simulated by following the speed trace from the California Air Resources Board HHDDT cycle. Emission rates for BUGs are reported as a function of engine load at constant speed using the ISO 8178B Cycle D2. The EC, OC, and PM emission rates were determined to be highly variable for the HHDDTs. It was determined that the per mile emission rate of OC from a HHDDT in congested traffic is 8.1 times higher than that of an HHDDT in cruise or highway speed conditions and 1.9 times higher for EC. EC/OC ratios for BUGs (which generally operate at steady states) and HHDDTs show marked differences, indicating that the transient nature of engine operation dictates the EC/OC ratio. Overall, this research shows that the EC/OC ratio varies widely for diesel engines in trucks and BUGs and depends strongly on the operating cycle. The findings reported here have significant implications in the application of chemical mass balance modeling, diesel risk assessment, and control strategies such as the Diesel Risk Reduction Program.

Multifidelity, multidisciplinary optimization of turbomachines with shock interaction

NASA Astrophysics Data System (ADS)

Joly, Michael Marie

Research on high-speed air-breathing propulsion aims at developing aircraft with antipodal range and space access. Before reaching high speed at high altitude, the flight vehicle needs to accelerate from takeoff to scramjet takeover. Air turbo rocket engines combine turbojet and rocket engine cycles to provide the necessary thrust in the so-called low-speed regime. Challenges related to turbomachinery components are multidisciplinary, since both the high compression ratio compressor and the powering high-pressure turbine operate in the transonic regime in compact environments with strong shock interactions. Besides, lightweight is vital to avoid hindering the scramjet operation. Recent progress in evolutionary computing provides aerospace engineers with robust and efficient optimization algorithms to address concurrent objectives. The present work investigates Multidisciplinary Design Optimization (MDO) of innovative transonic turbomachinery components. Inter-stage aerodynamic shock interaction in turbomachines are known to generate high-cycle fatigue on the rotor blades compromising their structural integrity. A soft-computing strategy is proposed to mitigate the vane downstream distortion, and shown to successfully attenuate the unsteady forcing on the rotor of a high-pressure turbine. Counter-rotation offers promising prospects to reduce the weight of the machine, with fewer stages and increased load per row. An integrated approach based on increasing level of fidelity and aero-structural coupling is then presented and allows achieving a highly loaded compact counter-rotating compressor.

Research of Modulation of Bilateral Frequency Difference Based on Load Mode

NASA Astrophysics Data System (ADS)

Lin, Shenghong; Mao, Chizu; Zhu, Jianquan; Lu, Junyu

2017-05-01

Owning to high reliability, simple operation and easy acquirement of signals, modulation of bilateral frequency difference (MBFD) in HVDC is worthy for application in practical engineering. With the example of an AC/DC hybrid network and the software PSD-BPA, this paper analyses the effect of MBFD to DC block. The modulators parameters are setting by means of simulation. Two types of loads modes are considered to research the impact of them on simulation. The results indicate that in cooperation with operation modes adjusting at AC system, MBFD will effectively release the impact from DC block and shortage of reactive power caused by rapid variation of DC power owning to modulation. To achieve the best effect, only modulators of some HVDC systems instead of all of them are opened.

Development of heat flux sensors for turbine airfoils and combustor liners

NASA Astrophysics Data System (ADS)

Atkinson, W. H.

1983-10-01

The design of durable turbine airfoils that use a minimum amount of cooling air requires knowledge of the heat loads on the airfoils during engine operation. Measurement of these heat loads will permit the verification or modification of the analytical models used in the design process and will improve the ability to predict and confirm the thermal performance of turbine airfoil designs. Heat flux sensors for turbine blades and vanes must be compatible with the cast nickel-base and cobalt-base materials used in their fabrication and will need to operate in a hostile environment with regard to temperature, pressure and thermal cycling. There is also a need to miniaturize the sensors to obtain measurements without perturbing the heat flows that are to be measured.

Influence of fuel properties, nitrogen oxides, and exhaust treatment by an oxidation catalytic converter on the mutagenicity of diesel engine emissions.

PubMed

Bünger, Jürgen; Krahl, Jürgen; Weigel, Andreas; Schröder, Olaf; Brüning, Thomas; Müller, Michael; Hallier, Ernst; Westphal, Götz

2006-08-01

Particle emissions of diesel engines (DEP) content polycyclic aromatic hydrocarbons (PAH) these compounds cause a strong mutagenicity of solvent extracts of DEP. We investigated the influence of fuel properties, nitrogen oxides (NO( x )), and an oxidation catalytic converter (OCC) on the mutagenic effects of DEP. The engine was fuelled with common diesel fuel (DF), low-sulphur diesel fuel (LSDF), rapeseed oil methyl ester (RME), and soybean oil methyl ester (SME) and run at five different load modes in two series with and without installation of an OCC in the exhaust pipe. Particles from the cooled and diluted exhaust were sampled onto glass fibre filters and extracted with dichloromethane in a soxhlet apparatus. The mutagenicity of the extracts was tested using the Salmonella typhimurium/mammalian microsome assay with tester strains TA98 and TA100. Without OCC the number of revertant colonies was lower in extracts of LSDF than in extracts of DF. The lowest numbers of revertant colonies were induced by the plant oil derived fuels. In three load modes, operation with the OCC led to a reduction of the mutagenicity. However, direct mutagenic effects under heavy duty conditions (load mode A) were significantly increased for RME (TA98, TA100) and SME (TA98). A consistent but not significant increase in direct mutagenicity was observed for DF and LSDF at load mode A, and for DF at idling (load mode E) when emissions were treated with the OCC. These results raise concern over the use of oxidation catalytic converters with diesel engines. We hypothesise that the OCC increases formation of direct acting mutagens under certain conditions by the reaction of NO( x ) with PAH resulting in the formation of nitrated-PAH. Most of these compounds are powerful direct acting mutagens.

Bio-derived Fuel Blend Dilution of Marine Engine Oil and Imapct on Friction and Wear Behavior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ajayi, Oyelayo O.; Lorenzo-Martin, Cinta; Fenske, George R.

To reduce the amount of petroleum-derived fuel used in vehicles and vessels powered by internal combustion engines, the addition of bio-derived fuel extenders is a common practice. Ethanol is perhaps the most common bio-derived fuel used for blending, and butanol is being evaluated as a promising alternative. The present study determined the fuel dilution rate of three lubricating oils (E0, E10, and i-B16) in a marine engine operating in on-water conditions with a start-and-stop cycle protocol. The level of fuel dilution increased with the number of cycles for all three fuels. The most dilution was observed with i-B16 fuel, andmore » the least with E10 fuel. In all cases, fuel dilution substantially reduced the oil viscosity. The impacts of fuel dilution and the consequent viscosity reduction on the lubricating capability of the engine oil in terms of friction, wear, and scuffing prevention were evaluated by four different tests protocols. Although the fuel dilution of the engine oil had minimal effect on friction, because the test conditions were under the boundary lubrication regime, significant effects were observed on wear in many cases. Fuel dilution also was observed to reduce the load-carrying capacity of the engine oils in terms of scuffing load reduction.« less

An assessment of thermodynamic merits for current and potential future engine operating strategies

DOE PAGES

Wissink, Martin L.; Splitter, Derek A.; Dempsey, Adam B.; ...

2017-02-01

The present work compares the fundamental thermodynamic underpinnings (i.e., working fluid properties and heat release profile) of various combustion strategies with engine measurements. The approach employs a model that separately tracks the impacts on efficiency due to differences in rate of heat addition, volume change, mass addition, and molecular weight change for a given combination of working fluid, heat release profile, and engine geometry. Comparative analysis between measured and modeled efficiencies illustrates fundamental sources of efficiency reductions or opportunities inherent to various combustion regimes. Engine operating regimes chosen for analysis include stoichiometric spark-ignited combustion and lean compression-ignited combustion including HCCI,more » SA-HCCI, RCCI, GCI, and CDC. Within each combustion regime, effects such as engine load, combustion duration, combustion phasing, combustion chamber geometry, fuel properties, and charge dilution are explored. Model findings illustrate that even in the absence of losses such as heat transfer or incomplete combustion, the maximum possible thermal efficiency inherent to each operating strategy varies to a significant degree. Additionally, the experimentally measured losses are observed to be unique within a given operating strategy. The findings highlight the fact that in order to create a roadmap for future directions in ICE technologies, it is important to not only compare the absolute real-world efficiency of a given combustion strategy, but to also examine the measured efficiency in context of what is thermodynamically possible with the working fluid and boundary conditions prescribed by a strategy.« less

An assessment of thermodynamic merits for current and potential future engine operating strategies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wissink, Martin L.; Splitter, Derek A.; Dempsey, Adam B.

The present work compares the fundamental thermodynamic underpinnings (i.e., working fluid properties and heat release profile) of various combustion strategies with engine measurements. The approach employs a model that separately tracks the impacts on efficiency due to differences in rate of heat addition, volume change, mass addition, and molecular weight change for a given combination of working fluid, heat release profile, and engine geometry. Comparative analysis between measured and modeled efficiencies illustrates fundamental sources of efficiency reductions or opportunities inherent to various combustion regimes. Engine operating regimes chosen for analysis include stoichiometric spark-ignited combustion and lean compression-ignited combustion including HCCI,more » SA-HCCI, RCCI, GCI, and CDC. Within each combustion regime, effects such as engine load, combustion duration, combustion phasing, combustion chamber geometry, fuel properties, and charge dilution are explored. Model findings illustrate that even in the absence of losses such as heat transfer or incomplete combustion, the maximum possible thermal efficiency inherent to each operating strategy varies to a significant degree. Additionally, the experimentally measured losses are observed to be unique within a given operating strategy. The findings highlight the fact that in order to create a roadmap for future directions in ICE technologies, it is important to not only compare the absolute real-world efficiency of a given combustion strategy, but to also examine the measured efficiency in context of what is thermodynamically possible with the working fluid and boundary conditions prescribed by a strategy.« less

Identification of Load Categories in Rotor System Based on Vibration Analysis

PubMed Central

Yang, Zhaojian

2017-01-01

Rotating machinery is often subjected to variable loads during operation. Thus, monitoring and identifying different load types is important. Here, five typical load types have been qualitatively studied for a rotor system. A novel load category identification method for rotor system based on vibration signals is proposed. This method is a combination of ensemble empirical mode decomposition (EEMD), energy feature extraction, and back propagation (BP) neural network. A dedicated load identification test bench for rotor system was developed. According to loads characteristics and test conditions, an experimental plan was formulated, and loading tests for five loads were conducted. Corresponding vibration signals of the rotor system were collected for each load condition via eddy current displacement sensor. Signals were reconstructed using EEMD, and then features were extracted followed by energy calculations. Finally, characteristics were input to the BP neural network, to identify different load types. Comparison and analysis of identifying data and test data revealed a general identification rate of 94.54%, achieving high identification accuracy and good robustness. This shows that the proposed method is feasible. Due to reliable and experimentally validated theoretical results, this method can be applied to load identification and fault diagnosis for rotor equipment used in engineering applications. PMID:28726754

Hybrid Engine Powered City Car: Fuzzy Controlled Approach

NASA Astrophysics Data System (ADS)

Rahman, Ataur; Mohiuddin, AKM; Hawlader, MNA; Ihsan, Sany

2017-03-01

This study describes a fuzzy controlled hybrid engine powered car. The car is powered by the lithium ion battery capacity of 1000 Wh is charged by the 50 cc hybrid engine and power regenerative mode. The engine is operated with lean mixture at 3000 rpm to charge the battery. The regenerative mode that connects with the engine generates electrical power of 500-600 W for the deceleration of car from 90 km/h to 20 km/h. The regenerated electrical power has been used to power the air-conditioning system and to meet the other electrical power. The battery power only used to propel the car. The regenerative power also found charging the battery for longer operation about 40 minutes and more. The design flexibility of this vehicle starts with whole-vehicle integration based on radical light weighting, drag reduction, and accessory efficiency. The energy efficient hybrid engine cut carbon dioxide (CO2) and nitrogen oxides (N2O) emission about 70-80% as the loads on the crankshaft such as cam-follower and its associated rotating components are replaced by electromagnetic systems, and the flywheel, alternator and starter motor are replaced by a motor generator. The vehicle was tested and found that it was able to travel 70 km/litre with the power of hybrid engine.

Discrete Event Supervisory Control Applied to Propulsion Systems

NASA Technical Reports Server (NTRS)

Litt, Jonathan S.; Shah, Neerav

2005-01-01

The theory of discrete event supervisory (DES) control was applied to the optimal control of a twin-engine aircraft propulsion system and demonstrated in a simulation. The supervisory control, which is implemented as a finite-state automaton, oversees the behavior of a system and manages it in such a way that it maximizes a performance criterion, similar to a traditional optimal control problem. DES controllers can be nested such that a high-level controller supervises multiple lower level controllers. This structure can be expanded to control huge, complex systems, providing optimal performance and increasing autonomy with each additional level. The DES control strategy for propulsion systems was validated using a distributed testbed consisting of multiple computers--each representing a module of the overall propulsion system--to simulate real-time hardware-in-the-loop testing. In the first experiment, DES control was applied to the operation of a nonlinear simulation of a turbofan engine (running in closed loop using its own feedback controller) to minimize engine structural damage caused by a combination of thermal and structural loads. This enables increased on-wing time for the engine through better management of the engine-component life usage. Thus, the engine-level DES acts as a life-extending controller through its interaction with and manipulation of the engine s operation.

Design analysis of a self-acting spiral-groove ring seal for counter-rotating shafts

NASA Technical Reports Server (NTRS)

Dirusso, E.

1983-01-01

A self-acting spiral groove inter-shaft ring seal of nominal 16.33 cm (6.43 in.) diameter for sealing fan bleed air between counter-rotating hafts in advanced turbofan engines was analyzed. The analysis focused on the lift force characteristics of the spiral grooves. A NASA Lewis developed computer program for predicting the performance of gas lubricated face seals was used to optimize the spiral groove geometry to produce maximum lift force. Load capacity curves (lift force as function of film thickness) were generated for four advanced turbofan engine operating conditions at relative seal speeds ranging from 17,850 to 29,800 rpm, sealed air pressures from 6 to 42 N/sq cm (9 to 60 psi) absolute and temperatures from 95 deg to 327 C (203 deg to 620 F). The relative seal sliding speed range was 152 to 255 m/sec (500 to 836 ft/sec). The analysis showed that the spiral grooves are capable of producing sufficient lift force such that the ring seal will operate in a noncontacting mode over the operating range of typical advanced turbofan engines.

Design analysis of a self-acting spiral-groove ring seal for counter-rotating shafts. [o ring seals

NASA Technical Reports Server (NTRS)

Dirusso, E.

1983-01-01

A self-acting spiral groove inter-shaft ring seal of nominal 16.33 cm (6.43 in.) diameter for sealing fan bleed air between counter rotating shafts in advanced turbofan engines was analyzed. The analysis focused on the lift force characteristics of the spiral grooves. A NASA Lewis developed computer program for predicting the performance of gas lubricated face seals was used to optimize the spiral groove geometry to produce maximum lift force. Load capacity curves (lift force as function of film thickness) were generated for four advanced turbofan engine operating conditions at relative seal speeds ranging from 17,850 to 29,800 rpm, sealed air pressures from 6 to 42 N/sq cm (9 to 60 psi) absolute and temperatures from 95 to 327 C (203 to 620 F). The relative seal sliding speed range was 152 to 255 m/sec (500 to 836 ft/sec). The analysis showed that the spiral grooves are capable of producing sufficient lift force such that the ring seal will operate in a noncontacting mode over the operating range of typical advanced turbofan engines.

Design and upgrades for the Sloan Digital Sky Survey telescope's roll-off enclosure

NASA Astrophysics Data System (ADS)

Leger, R. French; Long, Dan; Klaene, Mark A.

2003-02-01

The SDSS telescope is housed, when not in use, in a roll-off enclosure. This enclosure rolls away from the telescope a distance of 60 feet, leaving the telescope fully exposed for operations. Design considerations for wind and solar loading, thermal venting, conditioning and stability are reviewed. Originally, the enclosure had been constructed to minimize its surface area obstruction to the telescopes field of view. This design feature, however, offered little room to perform engineering tasks during non-operational time. An upgrade to the structure, in the form of raising the roof, was instituted. This improvement greatly enhanced the engineering and testing functions performed on the telescope, thereby increasing operational efficiency and the time allotted to engineering tasks. Problems maintaining and associated with weather sealing, lightning protection, truck wheel alignment, altitude effects on truck controllers and thermal conditioning are examined. Communication and electrical connections between stationary and moving elements of the enclosure are described. Two types of systems, to date, have been used one a reel and the other a slider system. Advantages and disadvantages of both are examined from the perspective of four years experience.

Effect of E85 on RCCI Performance and Emissions on a Multi-Cylinder Light-Duty Diesel Engine - SAE World Congress

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2012-01-01

This paper investigates the effect of E85 on load expansion and FTP modal point emissions indices under reactivity controlled compression ignition (RCCI) operation on a light-duty multi-cylinder diesel engine. A General Motors (GM) 1.9L four-cylinder diesel engine with the stock compression ratio of 17.5:1, common rail diesel injection system, high-pressure exhaust gas recirculation (EGR) system and variable geometry turbocharger was modified to allow for port fuel injection with gasoline or E85. Controlling the fuel reactivity in-cylinder by the adjustment of the ratio of premixed low-reactivity fuel (gasoline or E85) to direct injected high reactivity fuel (diesel fuel) has been shownmore » to extend the operating range of high-efficiency clean combustion (HECC) compared to the use of a single fuel alone as in homogeneous charge compression ignition (HCCI) or premixed charge compression ignition (PCCI). The effect of E85 on the Ad-hoc federal test procedure (FTP) modal points is explored along with the effect of load expansion through the light-duty diesel speed operating range. The Ad-hoc FTP modal points of 1500 rpm, 1.0bar brake mean effective pressure (BMEP); 1500rpm, 2.6bar BMEP; 2000rpm, 2.0bar BMEP; 2300rpm, 4.2bar BMEP; and 2600rpm, 8.8bar BMEP were explored. Previous results with 96 RON unleaded test gasoline (UTG-96) and ultra-low sulfur diesel (ULSD) showed that with stock hardware, the 2600rpm, 8.8bar BMEP modal point was not obtainable due to excessive cylinder pressure rise rate and unstable combustion both with and without the use of EGR. Brake thermal efficiency and emissions performance of RCCI operation with E85 and ULSD is explored and compared against conventional diesel combustion (CDC) and RCCI operation with UTG 96 and ULSD.« less

Thrust stand evaluation of engine performance improvement algorithms in an F-15 airplane

NASA Technical Reports Server (NTRS)

Conners, Timothy R.

1992-01-01

Results are presented from the evaluation of the performance seeking control (PSC) optimization algorithm developed by Smith et al. (1990) for F-15 aircraft, which optimizes the quasi-steady-state performance of an F100 derivative turbofan engine for several modes of operation. The PSC algorithm uses onboard software engine model that calculates thrust, stall margin, and other unmeasured variables for use in the optimization. Comparisons are presented between the load cell measurements, PSC onboard model thrust calculations, and posttest state variable model computations. Actual performance improvements using the PSC algorithm are presented for its various modes. The results of using PSC algorithm are compared with similar test case results using the HIDEC algorithm.

Development of a Thin Gauge Metallic Seal for Gas Turbine Engine Applications to 1700 F

NASA Technical Reports Server (NTRS)

England, Raymond O.

2006-01-01

The goal of doubling thrust-to-weight ratio for gas turbine engines has placed significant demands on engine component materials. Operating temperatures for static seals in the transition duct and turbine sections for instance, may well reach 2000 F within the next ten years. At these temperatures conventional age-hardenable superalloys lose their high strength via overaging and eventual dissolution of the gamma precipitate, and are well above their oxidation stability limit. Conventional solid-solution-strengthened alloys offer metallurgical stability, but suffer from rapid oxidation and little useful load bearing strength. Ceramic materials can theoretically be used at these temperatures, but manufacturing processes are in the developmental stages.

Testing and analysis of the impact on engine cycle parameters and control system modifications using hydrogen or methane as fuel in an industrial gas turbine

NASA Astrophysics Data System (ADS)

Funke, H. H.-W.; Keinz, J.; Börner, S.; Hendrick, P.; Elsing, R.

2016-07-01

The paper highlights the modification of the engine control software of the hydrogen (H2) converted gas turbine Auxiliary Power Unit (APU) GTCP 36-300 allowing safe and accurate methane (CH4) operation achieved without mechanical changes of the metering unit. The acceleration and deceleration characteristics of the engine controller from idle to maximum load are analyzed comparing H2 and CH4. Also, the paper presents the influence on the thermodynamic cycle of gas turbine resulting from the different fuels supported by a gas turbine cycle simulation of H2 and CH4 using the software GasTurb.

Free-piston Stirling Engine system considerations for various space power applications

NASA Technical Reports Server (NTRS)

Dochat, George R.; Dhar, Manmohan

1991-01-01

Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (ac, dc, high or low voltage, and fixed or variable load). This paper reviews potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. This paper briefly outlines the program and recent progress.

Autonomous Cryogenic Load Operations: Knowledge-Based Autonomous Test Engineer

NASA Technical Reports Server (NTRS)

Schrading, J. Nicolas

2013-01-01

The Knowledge-Based Autonomous Test Engineer (KATE) program has a long history at KSC. Now a part of the Autonomous Cryogenic Load Operations (ACLO) mission, this software system has been sporadically developed over the past 20 years. Originally designed to provide health and status monitoring for a simple water-based fluid system, it was proven to be a capable autonomous test engineer for determining sources of failure in the system. As part of a new goal to provide this same anomaly-detection capability for a complicated cryogenic fluid system, software engineers, physicists, interns and KATE experts are working to upgrade the software capabilities and graphical user interface. Much progress was made during this effort to improve KATE. A display of the entire cryogenic system's graph, with nodes for components and edges for their connections, was added to the KATE software. A searching functionality was added to the new graph display, so that users could easily center their screen on specific components. The GUI was also modified so that it displayed information relevant to the new project goals. In addition, work began on adding new pneumatic and electronic subsystems into the KATE knowledge base, so that it could provide health and status monitoring for those systems. Finally, many fixes for bugs, memory leaks, and memory errors were implemented and the system was moved into a state in which it could be presented to stakeholders. Overall, the KATE system was improved and necessary additional features were added so that a presentation of the program and its functionality in the next few months would be a success.

Autonomous Cryogenic Load Operations: KSC Autonomous Test Engineer

NASA Technical Reports Server (NTRS)

Shrading, Nicholas J.

2012-01-01

The KSC Autonomous Test Engineer (KATE) program has a long history at KSC. Now a part of the Autonomous Cryogenic Load Operations (ACLO) mission, this software system has been sporadically developed over the past 20+ years. Originally designed to provide health and status monitoring for a simple water-based fluid system, it was proven to be a capable autonomous test engineer for determining sources of failure in. the system, As part.of a new goal to provide this same anomaly-detection capability for a complicated cryogenic fluid system, software engineers, physicists, interns and KATE experts are working to upgrade the software capabilities and graphical user interface. Much progress was made during this effort to improve KATE. A display ofthe entire cryogenic system's graph, with nodes for components and edges for their connections, was added to the KATE software. A searching functionality was added to the new graph display, so that users could easily center their screen on specific components. The GUI was also modified so that it displayed information relevant to the new project goals. In addition, work began on adding new pneumatic and electronic subsystems into the KATE knowledgebase, so that it could provide health and status monitoring for those systems. Finally, many fixes for bugs, memory leaks, and memory errors were implemented and the system was moved into a state in which it could be presented to stakeholders. Overall, the KATE system was improved and necessary additional features were added so that a presentation of the program and its functionality in the next few months would be a success.

Factors influencing load-haul-dump operator line of sight in underground mining.

PubMed

Eger, Tammy; Salmoni, Alan; Whissell, Robert

2004-03-01

The inability of load-haul-dump (LHD) equipment operators to see people, objects or hazards around the LHD machine they drive is a causal factor in a number of serious accidents. Line of sight evaluations were conducted on 11 different LHD models. Results indicated blind spots were caused by cab posts, and vehicles lights and light brackets. Line of sight impairments were caused by wheel well covers, buckets, fire extinguisher, light posts, radiator covers, booms, radio remote boxes, elevated engine profiles and air intake cylinders. These results were supported by questionnaires completed by 130 LHD operators. The operators indicated the bucket, lights and light brackets, boom and cab impaired line of sight. Line of sight testing and LHD operator feedback indicated line of sight to the right front corner and back right corner were typically worse than line of sight to the front left side of the vehicle. Results of this study have been used to conduct awareness campaigns within the Ontario mining industry and to suggest vehicle design modifications to LHD manufacturers.

Knock detection system to improve petrol engine performance, using microphone sensor

NASA Astrophysics Data System (ADS)

Sujono, Agus; Santoso, Budi; Juwana, Wibawa Endra

2017-01-01

An increase of power and efficiency of spark ignition engines (petrol engines) are always faced with the problem of knock. Even the characteristics of the engine itself are always determined from the occurrence of knock. Until today, this knocking problem has not been solved completely. Knock is caused by principal factors that are influenced by the engine rotation, the load or opening the throttle and spark advance (ignition timing). In this research, the engine is mounted on the engine test bed (ETB) which is equipped with the necessary sensors. Knock detection using a new method, which is based on pattern recognition, which through the knock sound detection by using a microphone sensor, active filter, the regression of the normalized envelope function, and the calculation of the Euclidean distance is used for identifying knock. This system is implemented with a microcontroller which uses fuzzy logic controller ignition (FLIC), which aims to set proper spark advance, in accordance with operating conditions. This system can improve the engine performance for approximately 15%.

Simulation of the transient processes of load rejection under different accident conditions in a hydroelectric generating set

NASA Astrophysics Data System (ADS)

Guo, W. C.; Yang, J. D.; Chen, J. P.; Peng, Z. Y.; Zhang, Y.; Chen, C. C.

2016-11-01

Load rejection test is one of the essential tests that carried out before the hydroelectric generating set is put into operation formally. The test aims at inspecting the rationality of the design of the water diversion and power generation system of hydropower station, reliability of the equipment of generating set and the dynamic characteristics of hydroturbine governing system. Proceeding from different accident conditions of hydroelectric generating set, this paper presents the transient processes of load rejection corresponding to different accident conditions, and elaborates the characteristics of different types of load rejection. Then the numerical simulation method of different types of load rejection is established. An engineering project is calculated to verify the validity of the method. Finally, based on the numerical simulation results, the relationship among the different types of load rejection and their functions on the design of hydropower station and the operation of load rejection test are pointed out. The results indicate that: The load rejection caused by the accident within the hydroelectric generating set is realized by emergency distributing valve, and it is the basis of the optimization for the closing law of guide vane and the calculation of regulation and guarantee. The load rejection caused by the accident outside the hydroelectric generating set is realized by the governor. It is the most efficient measure to inspect the dynamic characteristics of hydro-turbine governing system, and its closure rate of guide vane set in the governor depends on the optimization result in the former type load rejection.

39. VIEW OF CHRYSLER WORKERS LOADING A SATURN IB BOOSTER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. VIEW OF CHRYSLER WORKERS LOADING A SATURN IB BOOSTER INTO THE EAST POSITION ON THE STATIC TEST TOWER. AS THE MAIN CONTRACTOR OF THE SATURN IB BOOSTER, CHRYSLER TOOK OVER OPERATIONS OF THE EAST POSITION OF THE STATIC TEST TOWER IN 1963. THAT SAME YEAR, THE WEST POSITION OF THE TEST TOWER WAS MODIFIED (AS SEEN IN THE PHOTO) FOR RESEARCH AND DEVELOPMENT TESTS OF THE SATURN V BOOSTER'S ENGINE, THE F-1. MARCH 1963, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Electrically-Assisted Turbocharger Development for Performance and Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, Milton

2000-08-20

Turbocharger transient lag inherently imposes a tradeoff between a robust engine response to transient load shifts and exhaust emissions. By itself, a well matched turbocharger for an engine has limited flexibility in improving this transient response. Electrically-assisted turbocharging has been seen as an attractive option to improve response and lower transient emissions. This paper presents the results of a multi-year joint CRADA between DDC and ORNL. Virtual lab diesel simulation models characterized the performance improvement potential of an electrically assisted turbocharger technology. Operating requirements to reduce transient duration between load shift time by up to 50% were determined. A turbomachinemore » has been conceptualized with an integrated motor-generator, providing transient burst boost plus energy recovery capability. Numerous electric motor designs were considered, and a prototype motor was developed, fabricated, and is undergoing tests. Power controls have been designed and fabricated.« less

Snubber assembly for turbine blades

DOEpatents

Marra, John J

2013-09-03

A snubber associated with a rotatable turbine blade in a turbine engine, the turbine blade including a pressure sidewall and a suction sidewall opposed from the pressure wall. The snubber assembly includes a first snubber structure associated with the pressure sidewall of the turbine blade, a second snubber structure associated with the suction sidewall of the turbine blade, and a support structure. The support structure extends through the blade and is rigidly coupled at a first end portion thereof to the first snubber structure and at a second end portion thereof to the second snubber structure. Centrifugal loads exerted by the first and second snubber structures caused by rotation thereof during operation of the engine are at least partially transferred to the support structure, such that centrifugal loads exerted on the pressure and suctions sidewalls of the turbine blade by the first and second snubber structures are reduced.

Particle and gaseous emissions from compressed natural gas and ultralow sulphur diesel-fuelled buses at four steady engine loads.

PubMed

Jayaratne, E R; Ristovski, Z D; Meyer, N; Morawska, L

2009-04-01

Exhaust emissions from thirteen compressed natural gas (CNG) and nine ultralow sulphur diesel in-service transport buses were monitored on a chassis dynamometer. Measurements were carried out at idle and at three steady engine loads of 25%, 50% and 100% of maximum power at a fixed speed of 60 km h(-1). Emission factors were estimated for particle mass and number, carbon dioxide and oxides of nitrogen for two types of CNG buses (Scania and MAN, compatible with Euro 2 and 3 emission standards, respectively) and two types of diesel buses (Volvo Pre-Euro/Euro1 and Mercedez OC500 Euro3). All emission factors increased with load. The median particle mass emission factor for the CNG buses was less than 1% of that from the diesel buses at all loads. However, the particle number emission factors did not show a statistically significant difference between buses operating on the two types of fuel. In this paper, for the very first time, particle number emission factors are presented at four steady state engine loads for CNG buses. Median values ranged from the order of 10(12) particles min(-)(1) at idle to 10(15) particles km(-)(1) at full power. Most of the particles observed in the CNG emissions were in the nanoparticle size range and likely to be composed of volatile organic compounds The CO2 emission factors were about 20% to 30% greater for the diesel buses over the CNG buses, while the oxides of nitrogen emission factors did not show any difference due to the large variation between buses.

Calculation of reinforced-concrete frame strength under a simultaneous static cross section load and a column lateral impact

NASA Astrophysics Data System (ADS)

Belov, Nikolay; Yugov, Nikolay; Kopanitsa, Dmitry; Kopanitsa, Georgy; Yugov, Alexey; Kaparulin, Sergey; Plyaskin, Andrey; Kalichkina, Anna; Ustinov, Artyom

2016-01-01

When designing buildings with reinforced concrete that are planned to resist dynamic loads it is necessary to calculate this structural behavior under operational static and emergency impact and blast loads. Calculations of the structures under shock-wave loads can be performed by solving dynamic equations that do not consider static loads. Due to this fact the calculation of reinforced concrete frame under a simultaneous static and dynamic load in full 3d settings becomes a very non trivial and resource consuming problem. This problem can be split into two tasks. The first one is a shock-wave problem that can be solved using software package RANET-3, which allows solving the problem using finite elements method adapted for dynamic task. This method calculates strain-stress state of the material and its dynamic destruction, which is considered as growth and consolidation of micro defects under loading. On the second step the results of the first step are taken as input parameters for quasi static calculation of simultaneous static and dynamic load using finite elements method in AMP Civil Engineering-11.

14 CFR 23.371 - Gyroscopic and aerodynamic loads.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Flight Loads § 23.371 Gyroscopic and aerodynamic loads. (a) Each engine mount and its supporting... engine mount and its supporting structure must meet the requirements of paragraph (a) of this section and.... (c) For airplanes certificated in the commuter category, each engine mount and its supporting...

14 CFR 23.371 - Gyroscopic and aerodynamic loads.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Flight Loads § 23.371 Gyroscopic and aerodynamic loads. (a) Each engine mount and its supporting... engine mount and its supporting structure must meet the requirements of paragraph (a) of this section and.... (c) For airplanes certificated in the commuter category, each engine mount and its supporting...

14 CFR 23.371 - Gyroscopic and aerodynamic loads.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Flight Loads § 23.371 Gyroscopic and aerodynamic loads. (a) Each engine mount and its supporting... engine mount and its supporting structure must meet the requirements of paragraph (a) of this section and.... (c) For airplanes certificated in the commuter category, each engine mount and its supporting...

14 CFR 23.371 - Gyroscopic and aerodynamic loads.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Flight Loads § 23.371 Gyroscopic and aerodynamic loads. (a) Each engine mount and its supporting... engine mount and its supporting structure must meet the requirements of paragraph (a) of this section and.... (c) For airplanes certificated in the commuter category, each engine mount and its supporting...

14 CFR 23.371 - Gyroscopic and aerodynamic loads.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Flight Loads § 23.371 Gyroscopic and aerodynamic loads. (a) Each engine mount and its supporting... engine mount and its supporting structure must meet the requirements of paragraph (a) of this section and.... (c) For airplanes certificated in the commuter category, each engine mount and its supporting...

Evaluation of load tracks and wear of two sets of bearings from space shuttle main engine high pressure oxygen turbopumps

NASA Technical Reports Server (NTRS)

Kannel, J. W.; Dufrane, K. F.

1985-01-01

Bearings supporting the rotor in the High Pressure Oxygen Turbopump (HPOTP) were examined. The No. 1 bearings from both units were in good condition and had successfully completed 5000 seconds of operation. The No. 2 bearings, which were in service the same length of time, were significantly degraded in the form of ball wear, race pitting, and damage from high axial loads. The No. 3 and 4 bearings were in generally acceptable condition. The general conclusion from the examinations was that improved cooling on the No. 2 bearings and further improvements in controlling axial and radial load would likely result in the HPOTP meeting the qualification test results.

Analysis of Acceleration, Airspeed, and Gust-Velocity Data From a Four-Engine Transport Airplane Operating Over a Northwestern United States Alaska Route

NASA Technical Reports Server (NTRS)

Engel, Jerome N.; Copp, Martin R.

1959-01-01

Acceleration, airspeed, and altitude data obtained with an NACA VGH recorder from a four-engine commercial transport airplane operating over a northwestern United States-Alaska route were evaluated to determine the magnitude and frequency of occurrence of gust and maneuver accelerations., operating airspeeds, and gust velocities. The results obtained were then compared with the results previously reported in NACA Technical Note 3475 for two similar airplanes operating over transcontinental routes in the United States. No large variations in the gust experience for the three operations were noted. The results indicate that the gust-load experience of the present operation closely approximated that of the central transcontinental route in the United States with which it is compared and showed differences of about 4 to 1 when compared with that of the southern transcontinental route in the United States. In general, accelerations due to gusts occurred much more frequently than those due to operational maneuvers. At a measured normal-acceleration increment of 0.5g, accelerations due to gusts occurred roughly 35 times more frequently than those due to operational maneuvers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sevik, James; Wallner, Thomas; Pamminger, Michael

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 coilmore » 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.« less

Wave Phase-Sensitive Transformation of 3d-Straining of Mechanical Fields

NASA Astrophysics Data System (ADS)

Smirnov, I. N.; Speranskiy, A. A.

2015-11-01

It is the area of research of oscillatory processes in elastic mechanical systems. Technical result of innovation is creation of spectral set of multidimensional images which reflect time-correlated three-dimensional vector parameters of metrological, and\\or estimated, and\\or design parameters of oscillations in mechanical systems. Reconstructed images of different dimensionality integrated in various combinations depending on their objective function can be used as homeostatic profile or cybernetic image of oscillatory processes in mechanical systems for an objective estimation of current operational conditions in real time. The innovation can be widely used to enhance the efficiency of monitoring and research of oscillation processes in mechanical systems (objects) in construction, mechanical engineering, acoustics, etc. Concept method of vector vibrometry based on application of vector 3D phase- sensitive vibro-transducers permits unique evaluation of real stressed-strained states of power aggregates and loaded constructions and opens fundamental innovation opportunities: conduct of continuous (on-line regime) reliable monitoring of turboagregates of electrical machines, compressor installations, bases, supports, pipe-lines and other objects subjected to damaging effect of vibrations; control of operational safety of technical systems at all the stages of life cycle including design, test production, tuning, testing, operational use, repairs and resource enlargement; creation of vibro-diagnostic systems of authentic non-destructive control of anisotropic characteristics of materials resistance of power aggregates and loaded constructions under outer effects and operational flaws. The described technology is revolutionary, universal and common for all branches of engineering industry and construction building objects.

Wind loading on solar concentrators: some general considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roschke, E. J.

A survey has been completed to examine the problems and complications arising from wind loading on solar concentrators. Wind loading is site specific and has an important bearing on the design, cost, performance, operation and maintenance, safety, survival, and replacement of solar collecting systems. Emphasis herein is on paraboloidal, two-axis tracking systems. Thermal receiver problems also are discussed. Wind characteristics are discussed from a general point of view; current methods for determining design wind speed are reviewed. Aerodynamic coefficients are defined and illustrative examples are presented. Wind tunnel testing is discussed, and environmental wind tunnels are reviewed; recent results onmore » heliostat arrays are reviewed as well. Aeroelasticity in relation to structural design is discussed briefly. Wind loads, i.e., forces and moments, are proportional to the square of the mean wind velocity. Forces are proportional to the square of concentrator diameter, and moments are proportional to the cube of diameter. Thus, wind loads have an important bearing on size selection from both cost and performance standpoints. It is concluded that sufficient information exists so that reasonably accurate predictions of wind loading are possible for a given paraboloidal concentrator configuration, provided that reliable and relevant wind conditions are specified. Such predictions will be useful to the design engineer and to the systems engineer as well. Information is lacking, however, on wind effects in field arrays of paraboloidal concentrators. Wind tunnel tests have been performed on model heliostat arrays, but there are important aerodynamic differences between heliostats and paraboloidal dishes.« less

Emergy analysis of a farm biogas project in China: A biophysical perspective of agricultural ecological engineering

NASA Astrophysics Data System (ADS)

Zhou, S. Y.; Zhang, B.; Cai, Z. F.

2010-05-01

This paper aims to present a biophysical understanding of the agricultural ecological engineering by emergy analysis for a farm biogas project in China as a representative case. Accounting for the resource inputs into and accumulation within the project, as well as the outputs to the social system, emergy analysis provides an empirical study in the biophysical dimension of the agricultural ecological engineering. Economic benefits and ecological economic benefits of the farm biogas project indicated by market value and emergy monetary value are discussed, respectively. Relative emergy-based indices such as renewability (R%), emergy yield ratio (EYR), environmental load ratio (ELR) and environmental sustainability index (ESI) are calculated to evaluate the environmental load and local sustainability of the concerned biogas project. The results show that the farm biogas project has more reliance on the local renewable resources input, less environmental pressure and higher sustainability compared with other typical agricultural systems. In addition, holistic evaluation and its policy implications for better operation and management of the biogas project are presented.

Underway Recovery Test 6 (URT-6) - Day 5 Activities

NASA Image and Video Library

2018-01-21

Lead Instrumentation Engineer Kevin Taylor keeps an eye on the load levels during Underway Recovery Test 6 operations off the coast of San Diego. Kennedy Space Center’s NASA Recovery Team works with the U.S. Navy to improve recovery procedures and hardware ahead of Orion's next flight, Exploration Mission-1, when it splashes down in the Pacific Ocean.

Method for treating engine exhaust by use of hydrothermally stable, low-temperature NO.sub.x reduction NH3-SCR catalysts

DOEpatents

Narula, Chaitanya K.; Yang, Xiaofan

2017-07-04

A catalyst composition includes a heterobimetallic zeolite characterized by a chabazite structure loaded with copper ions and at least one trivalent metal ion other than Al.sup.3+. The catalyst composition decreases NO.sub.x emissions in diesel exhaust and is suitable for operation in a catalytic converter.

Supercruiser Arrow HS-8

NASA Technical Reports Server (NTRS)

Lord, Paul; Kao, Edward; Abobo, Joey B.; Collins, Todd A.; Ma, Leong; Murad, Adnan; Naran, Hitesh; Nguyen, Thuan P.; Nuon, Timithy I.; Thomas, Dimitri D.

1992-01-01

Technology in aeronautics has advanced dramatically since the last design of a production High Speed Civil Transport (HSCT) aircraft. Newly projected requirements call for a new High Speed Civil Transport aircraft with a range of approximately 550 nm and at least 275 passenger capacity. The aircraft must be affordable and marketable. The new HSCT must be able to sustain long-duration flights and to absorb the abuse of daily operation. The new aircraft must be safe and simple to fly and require a minimum amount of maintenance. This aircraft must meet FAA certification criteria of FAR Part 25 and environmental constraints. Several design configurations were examined and two designs were selected for further investigation. The first design employs the delta planform wings and conventional empennage layout. The other design uses a swing wing layout and conventional empennage. Other engineering challenges, including materials and propulsion are also discussed. At a cruise flight speed between Mach 2.2 and Mach 3.0, no current generation of materials can endure the thermal loading of supersonic flight and satisfy the stringent weight requirements. A new generation of lightweight composite materials must be developed for the HSCT. With the enforcement of stage 3 noise restrictions, these new engines must be able to propel the aircraft and satisfy the noise limit. The engine with the most promise is the variable cycle engine. At low subsonic speeds the engine operates like a turbofan engine, providing the most efficient performance. At higher speeds the variable cycle engine operates as a turbojet power plant. The two large engine manufacturers, General Electric and Pratt & Whitney in the United States, are combining forces to make the variable cycle engine a reality.

Analysis of heat recovery of diesel engine using intermediate working fluid

NASA Astrophysics Data System (ADS)

Jin, Lei; Zhang, Jiang; Tan, Gangfeng; Liu, Huaming

2017-07-01

The organic Rankine cycle (ORC) is an effective way to recovery the engine exhaust heat. The thermal stability of the evaporation system is significant for the stable operation of the ORC system. In this paper, the performance of the designed evaporation system which combines with the intermediate fluid for recovering the exhaust waste heat from a diesel engine is evaluated. The thermal characteristics of the target diesel engine exhaust gas are evaluated based on the experimental data firstly. Then, the mathematical model of the evaporation system is built based on the geometrical parameters and the specific working conditions of ORC. Finally, the heat transfer characteristics of the evaporation system are estimated corresponding to three typical operating conditions of the diesel engine. The result shows that the exhaust temperature at the evaporator outlet increases slightly with the engine speed and load. In the evaporator, the heat transfer coefficient of the Rankine working fluid is slightly larger than the intermediate fluid. However, the heat transfer coefficient of the intermediate fluid in the heat exchanger is larger than the exhaust side. The heat transfer areas of the evaporator in both the two-phase zone and the preheated zone change slightly along with the engine working condition while the heat transfer areas of the overheated zone has changed obviously. The maximum heat transfer rate occurs in the preheating zone while the minimum value occurs in the overheating zone. In addition, the Rankine working fluid temperature at the evaporator outlet is not sensitively affected by the torque and speed of the engine and the organic fluid flow is relatively stable. It is concluded that the intermediate fluid could effectively reduce the physical changes of Rankine working fluid in the evaporator outlet due to changes in engine operating conditions.

Analytical and experimental investigations of the oblique detonation wave engine concept

NASA Technical Reports Server (NTRS)

Menees, Gene P.; Adelman, Henry G.; Cambier, Jean-Luc

1990-01-01

Wave combustors, which include the oblique detonation wave engine (ODWE), are attractive propulsion concepts for hypersonic flight. These engines utilize oblique shock or detonation waves to rapidly mix, ignite, and combust the air-fuel mixture in thin zones in the combustion chamber. Benefits of these combustion systems include shorter and lighter engines which require less cooling and can provide thrust at higher Mach numbers than conventional scramjets. The wave combustor's ability to operate at lower combustor inlet pressures may allow the vehicle to operate at lower dynamic pressures which could lessen the heating loads on the airframe. The research program at NASA-Ames includes analytical studies of the ODWE combustor using Computational Fluid Dynamics (CFD) codes which fully couple finite rate chemistry with fluid dynamics. In addition, experimental proof-of-concept studies are being performed in an arc heated hypersonic wind tunnel. Several fuel injection design were studied analytically and experimentally. In-stream strut fuel injectors were chosen to provide good mixing with minimal stagnation pressure losses. Measurements of flow field properties behind the oblique wave are compared to analytical predictions.

Analytical and experimental investigations of the oblique detonation wave engine concept

NASA Technical Reports Server (NTRS)

Menees, Gene P.; Adelman, Henry G.; Cambier, Jean-Luc

1991-01-01

Wave combustors, which include the Oblique Detonation Wave Engine (ODWE), are attractive propulsion concepts for hypersonic flight. These engines utilize oblique shock or detonation waves to rapidly mix, ignite, and combust the air-fuel mixture in thin zones in the combustion chamber. Benefits of these combustion systems include shorter and lighter engines which will require less cooling and can provide thrust at higher Mach numbers than conventional scramjets. The wave combustor's ability to operate at lower combustor inlet pressures may allow the vehicle to operate at lower dynamic pressures which could lessen the heating loads on the airframe. The research program at NASA-Ames includes analytical studies of the ODWE combustor using CFD codes which fully couple finite rate chemistry with fluid dynamics. In addition, experimental proof-of-concept studies are being carried out in an arc heated hypersonic wind tunnel. Several fuel injection designs were studied analytically and experimentally. In-stream strut fuel injectors were chosen to provide good mixing with minimal stagnation pressure losses. Measurements of flow field properties behind the oblique wave are compared to analytical predictions.

Modeling Radiative Heat Transfer and Turbulence-Radiation Interactions in Engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul, Chandan; Sircar, Arpan; Ferreyro-Fernandez, Sebastian

Detailed radiation modelling in piston engines has received relatively little attention to date. Recently, it is being revisited in light of current trends towards higher operating pressures and higher levels of exhaust-gas recirculation, both of which enhance molecular gas radiation. Advanced high-efficiency engines also are expected to function closer to the limits of stable operation, where even small perturbations to the energy balance can have a large influence on system behavior. Here several different spectral radiation property models and radiative transfer equation (RTE) solvers have been implemented in an OpenFOAM-based engine CFD code, and simulations have been performed for amore » full-load (peak pressure ~200 bar) heavy-duty diesel engine. Differences in computed temperature fields, NO and soot levels, and wall heat transfer rates are shown for different combinations of spectral models and RTE solvers. The relative importance of molecular gas radiation versus soot radiation is examined. And the influence of turbulence-radiation interactions is determined by comparing results obtained using local mean values of composition and temperature to compute radiative emission and absorption with those obtained using a particle-based transported probability density function method.« less

Simulated Lunar Testing of Metabolic Heat Regenerated Temperature Swing Adsorption Technology

NASA Technical Reports Server (NTRS)

Padilla, Sebastian A.; Bower, Chad; Iacomini, Christie S.; Paul, H.

2011-01-01

Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal and carbon dioxide (CO2) control for a Portable Life Support System (PLSS), as well as water recycling. An Engineering Development Unit (EDU) of the MTSA subassembly was designed and assembled for optimized Martian operations, but also meets system requirements for lunar operations. For lunar operations the MTSA sorption cycle is driven via a vacuum swing between suit ventilation loop pressure and lunar vacuum. The focus of this effort is operations and testing in a simulated lunar environment. This environment was simulated in Paragon s EHF vacuum chamber. The objective of this testing was to evaluate the full cycle performance of the MTSA Subassembly EDU, and to assess CO2 loading and pressure drop of the wash coated aluminum reticulated foam sorbent bed. The lunar testing proved out the feasibility of pure vacuum swing operation, making MTSA a technology that can be tested and used on the Moon prior to going to Mars. Testing demonstrated better than expected CO2 loading on the sorbent and nearly replicates the equilibrium data from the sorbent manufacturer. This had not been achieved in any of the previous sorbent loading tests performed by Paragon. Subsequently, the increased performance of the sorbent bed design indicates future designs will require less mass and volume than the current EDU rendering MTSA as very competitive for Martian PLSS applications.

Pressure and temperature effects on fuels with varying octane sensitivity at high load in SI engines

DOE PAGES

Szybist, James P.; Splitter, Derek A.

2017-01-06

The octane sensitivity (S), defined as the difference between the Research Octane Number (RON) and the Motor Octane Number (MON), is of increasing interest in spark ignition (SI) engines because of its relevance to knock resistance at boosted high load conditions. In this study, three fuels with nearly constant RON (99.2-100) and varying S (S = 0, 6.5, and 12) are operated at the knock limited spark advance (KLSA) at nominal engine loads of 10, 15, and 20 bar IMEP in a single cylinder SI engine with side-mount direct injection fueling, at λ =1 stoichiometry. At each load condition, themore » intake manifold temperature is swept from 35 °C to 95 °C to alter the temperature and pressure history of the charge. Results show that at the 10 bar IMEP condition, knock resistance is inversely proportional to fuel S where the S=0 fuel is the most knock resist, but as load increases the trend reverses and knock resistance becomes proportional to fuel S, and the S=12 fuel is the most knock resistant. The reversal of knock resistance as a function of S with load it is attributed to changing fuel ignition delay, as bulk gas intermediate temperature heat release (ITHR) is observed for the S = 0 several crank angles prior to the spark command and ITHR magnitude is a function of increasing intake temperature. As intake temperature continued to increase, the S=0 fuel transitioned from ITHR to low-temperature heat release (LTHR) prior to the spark event. At the highest load and intake temperature, 95 C, the S=0 fuel exhibits distinct LTHR and negative temperature coefficient (NTC), and the intermediate S value fuel (S=6.5) exhibited distinct ITHR behavior several crank angles prior to the spark command. However, for the tested conditions, the S=12 fuel exhibits neither ITHR nor LTHR. To understand the measured trends, chemical kinetic modeling is used to elucidate the fuel specific dependencies on in-cylinder temperature and pressure history. Lastly, the bulk gas composition change that occurs for fuels and conditions exhibiting ITHR and LTHR is analyzed in the modeling, including their implications on flame speed and combustion stability at late phasing. Furthermore, the combined findings illustrate the commonality and utility of fuel S, ITHR, LTHR, and NTC across a wide range of conditions, and the associated implications of fuel S in highly boosted modern GDI SI engines relative to the RON and MON tests.« less

Differences between emissions measured in urban driving and certification testing of heavy-duty diesel engines

NASA Astrophysics Data System (ADS)

Dixit, Poornima; Miller, J. Wayne; Cocker, David R.; Oshinuga, Adewale; Jiang, Yu; Durbin, Thomas D.; Johnson, Kent C.

2017-10-01

Emissions from eight heavy-duty diesel trucks (HDDTs) equipped with three different exhaust aftertreatment systems (ATS) for controlling nitrogen oxide (NOx) emissions were quantified on a chassis dynamometer using driving schedules representative of stop-and-go and free-flow driving in metropolitan areas. The three control technologies were: 1) cooled exhaust gas recirculation (CEGR) plus a diesel particulate filter (DPF); 2) CEGR and DPF plus advanced engine controls; and 3) CEGR and DPF plus selective catalytic reduction with ammonia (SCR). Results for all control technologies and driving conditions showed PM emission factors were less than the standard, while selected non-regulated emissions (ammonia, carbonyls, and C4-C12 hydrocarbons) and a greenhouse gas (nitrous oxide) were at measurement detection limits. However, NOx emission factors depended on the control technology, engine calibration, and driving mode. For example, emissions from engines with cooled-exhaust gas recirculation (CEGR) were 239% higher for stop-and-go driving as compared with free-flow. For CEGR plus selective catalytic reduction (SCR), the ratio was 450%. A deeper analysis was carried out with the assumption that emissions measured for a drive cycle on either the chassis or in-use driving would be similar. Applying the same NTE rules to the chassis data showed emissions during stop-and-go driving often exceeded the certification standard and >90% of the driving did not fall within the Not-To-Exceed (NTE) control area suggesting the NTE requirements do not provide sufficient emissions control under in-use conditions. On-road measurement of emissions using the same mobile lab while the vehicle followed a free-flow driving schedule verified the chassis results. These results have implications for scientists who build inventories using certification values instead of real world emission values and for metropolitan populations, who are exposed to elevated emissions. The differences in values between real world emissions and certification cycles should be narrowed. For example, one might use a different mix of cold and hot start testing to greater emphasize low temperature/load operation, a separate cycle to specifically characterize low-load operation, or broaden the in-use compliance testing requirements and associated conformity factors to incorporate a wider envelope of vehicle operation, especially at low load conditions. .

INNOVATIVE HYBRID GAS/ELECTRIC CHILLER COGENERATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Todd Kollross; Mike Connolly

2004-06-30

Engine-driven chillers are quickly gaining popularity in the market place (increased from 7,000 tons in 1994 to greater than 50,000 tons in 1998) due to their high efficiency, electric peak shaving capability, and overall low operating cost. The product offers attractive economics (5 year pay back or less) in many applications, based on areas cooling requirements and electric pricing structure. When heat is recovered and utilized from the engine, the energy resource efficiency of a natural gas engine-driven chiller is higher than all competing products. As deregulation proceeds, real time pricing rate structures promise high peak demand electric rates, butmore » low off-peak electric rates. An emerging trend with commercial building owners and managers who require air conditioning today is to reduce their operating costs by installing hybrid chiller systems that combine gas and electric units. Hybrid systems not only reduce peak electric demand charges, but also allow customers to level their energy load profiles and select the most economical energy source, gas or electricity, from hour to hour. Until recently, however, all hybrid systems incorporated one or more gas-powered chillers (engine driven and/or absorption) and one or more conventional electric units. Typically, the cooling capacity of hybrid chiller plants ranges from the hundreds to thousands of refrigeration tons, with multiple chillers affording the user a choice of cooling systems. But this flexibility is less of an option for building operators who have limited room for equipment. To address this technology gap, a hybrid chiller was developed by Alturdyne that combines a gas engine, an electric motor and a refrigeration compressor within a single package. However, this product had not been designed to realize the full features and benefits possible by combining an engine, motor/generator and compressor. The purpose of this project is to develop a new hybrid chiller that can (1) reduce end-user energy costs, (2) lower building peak electric load, (3) increase energy efficiency, and (4) provide standby power. This new hybrid product is designed to allow the engine to generate electricity or drive the chiller's compressor, based on the market price and conditions of the available energy sources. Building owners can minimize cooling costs by operating with natural gas or electricity, depending on time of day energy rates. In the event of a backout, the building owner could either operate the product as a synchronous generator set, thus providing standby power, or continue to operate a chiller to provide air conditioning with support of a small generator set to cover the chiller's electric auxiliary requirements. The ability to utilize the same piece of equipment as a hybrid gas/electric chiller or a standby generator greatly enhances its economic attractiveness and would substantially expand the opportunities for high efficiency cooling products.« less

Physical properties, chemical composition, and cloud forming potential of particulate emissions from a marine diesel engine at various load conditions.

PubMed

Petzold, A; Weingartner, E; Hasselbach, J; Lauer, P; Kurok, C; Fleischer, F

2010-05-15

Particulate matter (PM) emissions from one serial 4-stroke medium-speed marine diesel engine were measured for load conditions from 10% to 110% in test rig studies using heavy fuel oil (HFO). Testing the engine across its entire load range permitted the scaling of exhaust PM properties with load. Emission factors for particle number, particle mass, and chemical compounds were determined. The potential of particles to form cloud droplets (cloud condensation nuclei, CCN) was calculated from chemical composition and particle size. Number emission factors are (3.43 +/- 1.26) x 10(16) (kg fuel)(-1) at 85-110% load and (1.06 +/- 0.10) x 10(16) (kg fuel)(-1) at 10% load. CCN emission factors of 1-6 x 10(14) (kg fuel)(-1) are at the lower bound of data reported in the literature. From combined thermal and optical methods, black carbon (BC) emission factors of 40-60 mg/(kg fuel) were determined for 85-100% load and 370 mg/(kg fuel) for 10% load. The engine load dependence of the conversion efficiency for fuel sulfur into sulfate of (1.08 +/- 0.15)% at engine idle to (3.85 +/- 0.41)% at cruise may serve as input to global emission calculations for various load conditions.

Analytical evaluation of the impact of broad specification fuels on high bypass turbofan engine combustors

NASA Technical Reports Server (NTRS)

Lohmann, R. P.; Szetela, E. J.; Vranos, A.

1978-01-01

The impact of the use of broad specification fuels on the design, performance durability, emissions and operational characteristics of combustors for commercial aircraft gas turbine engines was assessed. Single stage, vorbix and lean premixed prevaporized combustors, in the JT9D and an advanced energy efficient engine cycle were evaluated when operating on Jet A and ERBS (Experimental Referee Broad Specification) fuels. Design modifications, based on criteria evolved from a literature survey, were introduced and their effectiveness at offsetting projected deficiencies resulting from the use of ERBS was estimated. The results indicate that the use of a broad specification fuel such as ERBS, will necessitate significant technology improvements and redesign if deteriorated performance, durability and emissions are to be avoided. Higher radiant heat loads are projected to seriously compromise liner life while the reduced thermal stability of ERBS will require revisions to the engine-airframe fuel system to reduce the thermal stress on the fuel. Smoke and emissions output are projected to increase with the use of broad specification fuels. While the basic geometry of the single stage and vorbix combustors are compatible with the use of ERBS, extensive redesign of the front end of the lean premixed prevaporized burner will be required to achieve satisfactory operation and optimum emissions.

Feasibility Study of Vapor-Mist Phase Reaction Lubrication Using a Thioether Liquid

NASA Technical Reports Server (NTRS)

Morales, Wilfredo; Handschuh, Robert F.; Krantz, Timothy L.

2007-01-01

A primary technology barrier preventing the operation of gas turbine engines and aircraft gearboxes at higher temperatures is the inability of currently used liquid lubricants to survive at the desired operating conditions over an extended time period. Current state-of-the-art organic liquid lubricants rapidly degrade at temperatures above 300 C; hence, another form of lubrication is necessary. Vapor or mist phase reaction lubrication is a unique, alternative technology for high temperature lubrication. The majority of past studies have employed a liquid phosphate ester that was vaporized or misted, and delivered to bearings or gears where the phosphate ester reacted with the metal surfaces generating a solid lubricious film. This method resulted in acceptable operating temperatures suggesting some good lubrication properties, but the continuous reaction between the phosphate ester and the iron surfaces led to wear rates unacceptable for gas turbine engine or aircraft gearbox applications. In this study, an alternative non-phosphate liquid was used to mist phase lubricate a spur gearbox rig operating at 10,000 rpm under highly loaded conditions. After 21 million shaft revolutions of operation the gears exhibited only minor wear.

An evaluation of dry film lubricants and substrate materials for use on SSME gimbal bearings

NASA Technical Reports Server (NTRS)

Harp, J. A.

1976-01-01

Failure of the spherical bearing shaft of the Space Shuttle Main Engine (SSME) gimbal bearing assembly was encountered during Design Verification Specification testing of the full scale engine. Investigation revealed that the failure was caused by a deficiency in the lubrication system. Based upon the materials and gimbal operating conditions, a lubricant of MoS2 and graphite with a ceramic binder was the best lubricant candidate for this particular application; however, the decision to implement the change was not made without verification testing. Scaled down simulation testing was performed. Four different substrate materials and eight different dry film lubricants were subjected to tests under simulated SSME environmental and stress load conditions. The test specimens were evaluated for friction and operating life. Each test specimen was subjected to cyclic operation under load until failure. The force required to move the bearing surfaces relative to each other was monitored throughout the test, thus providing analytical data for derivation of the coefficient of friction. Results indicate that the MoS2/graphite lubricant with ceramic binder proved to be superior from the standpoint of endurance and also from the standpoint of friction reducing capabilities when applied to the titanium substrate material used on SSME. Endurance of this lubricant was approximately 16 times that of the lubricant which was being used when the SSME gimbal failed.

Present capabilities and future requirements for computer-aided geometric modeling in the design and manufacture of gas turbine

NASA Technical Reports Server (NTRS)

Caille, E.; Propen, M.; Hoffman, A.

1984-01-01

Gas turbine engine design requires the ability to rapidly develop complex structures which are subject to severe thermal and mechanical operating loads. As in all facets of the aerospace industry, engine designs are constantly driving towards increased performance, higher temperatures, higher speeds, and lower weight. The ability to address such requirements in a relatively short time frame has resulted in a major thrust towards integrated design/analysis/manufacturing systems. These computer driven graphics systems represent a unique challenge, with major payback opportunities if properly conceived, implemented, and applied.

Stability analysis of free piston Stirling engines

NASA Astrophysics Data System (ADS)

Bégot, Sylvie; Layes, Guillaume; Lanzetta, François; Nika, Philippe

2013-03-01

This paper presents a stability analysis of a free piston Stirling engine. The model and the detailed calculation of pressures losses are exposed. Stability of the machine is studied by the observation of the eigenvalues of the model matrix. Model validation based on the comparison with NASA experimental results is described. The influence of operational and construction parameters on performance and stability issues is exposed. The results show that most parameters that are beneficial for machine power seem to induce irregular mechanical characteristics with load, suggesting that self-sustained oscillations could be difficult to maintain and control.

Fuel Lubricity Impact on Shipboard Engine and Fuel Systems and Sensitivity of U.S. Navy Diesel Engines to Low-Sulfur Diesel Fuel

DTIC Science & Technology

2011-06-30

load fuel and operated with a dummy injector to make sure the system was clean. The rig was de -fueled and a fresh charge of 2000-gram fuel was added...the rocker arm on the injector. The rocker arm contact was repositioned when it was noted it was hitting the injector off-center, and it was felt...going up. Figure B6. DD 149 Unit Injector with Diesel Fuel and Centered Rocker Arm Figure B7. Wear Rate Deviation Attributed to Head

KSC-2012-3731

NASA Image and Video Library

2012-07-09

CAPE CANAVERAL, Fla. – Near the Hypergolic Maintenance Facility at NASA’s Kennedy Space Center in Florida, a groundbreaking ceremony was held to mark the location of the Ground Operations Demonstration Unit Liquid Hydrogen, or GODU LH2, test site. From left, are Johnny Nguyen, Fluids Test and Technology Development branch chief Emily Watkins, engineering intern Jeff Walls, Engineering Services Contract, or ESC, Cryogenics Test Lab engineer Kelly Currin, systems engineer Stephen Huff and Rudy Werlink partially hidden, cryogenics engineers Angela Krenn, systems engineer Doug Hammond, command and control engineer in the electrical division William Notardonato, GODU LH2 project manager and Kevin Jumper, ESC Cryogenics Test Lab manager. The GODU LH2 test site is one of the projects in NASA’s Advanced Exploration Systems Program. The site will be used to demonstrate advanced liquid hydrogen systems that are cost and energy efficient ways to store and transfer liquid hydrogen during process, loading, launch and spaceflight. The main components of the site will be a storage tank and a cryogenic refrigerator. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-3732

NASA Image and Video Library

2012-07-09

CAPE CANAVERAL, Fla. – Near the Hypergolic Maintenance Facility at NASA’s Kennedy Space Center in Florida, a groundbreaking ceremony was held to mark the location of the Ground Operations Demonstration Unit Liquid Hydrogen, or GODU LH2, test site. From left, are Johnny Nguyen, Fluids Test and Technology Development branch chief Emily Watkins, engineering intern Jeff Walls, Engineering Services Contract, or ESC, Cryogenics Test Lab engineer Kelly Currin, systems engineer Stephen Huff and Rudy Werlink partially hidden, cryogenics engineers Angela Krenn, systems engineer Doug Hammond, command and control engineer in the electrical division William Notardonato, GODU LH2 project manager and Kevin Jumper, ESC Cryogenics Test Lab manager. The GODU LH2 test site is one of the projects in NASA’s Advanced Exploration Systems Program. The site will be used to demonstrate advanced liquid hydrogen systems that are cost and energy efficient ways to store and transfer liquid hydrogen during process, loading, launch and spaceflight. The main components of the site will be a storage tank and a cryogenic refrigerator. Photo credit: NASA/Dimitri Gerondidakis

Method for reduction of the NOX emissions in marine auxiliary diesel engine using the fuel mixtures containing biodiesel using HCCI combustion.

PubMed

Puškár, Michal; Kopas, Melichar; Puškár, Dušan; Lumnitzer, Ján; Faltinová, Eva

2018-02-01

The marine auxiliary diesel engines installed in the large transoceanic ships are used in order to generate the electricity but at the same time these engines are able to produce a significant amount of the harmful exhaust gas emissions. Therefore the International Maritime Organisation (IMO) concluded an agreement, which has to control generating of gaseous emissions in maritime transport. From this reason started to be used some of the alternative fuels in this branch. There was performed a study, which investigated emissions of the auxiliary marine diesel engine during application of the experimental fuels. The different testing fuels were created using the ratios 0%, 50%, 80% and 100% between the biodiesel and the ULSDF (Ultra Low Sulphur Diesel Fuel). The experimental measurements were performed at the different engine loading levels and various engine speeds in order to investigate an influence of the mixed fuels on the engine operational characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development and applications of various optimization algorithms for diesel engine combustion and emissions optimization

NASA Astrophysics Data System (ADS)

Ogren, Ryan M.

For this work, Hybrid PSO-GA and Artificial Bee Colony Optimization (ABC) algorithms are applied to the optimization of experimental diesel engine performance, to meet Environmental Protection Agency, off-road, diesel engine standards. This work is the first to apply ABC optimization to experimental engine testing. All trials were conducted at partial load on a four-cylinder, turbocharged, John Deere engine using neat-Biodiesel for PSO-GA and regular pump diesel for ABC. Key variables were altered throughout the experiments, including, fuel pressure, intake gas temperature, exhaust gas recirculation flow, fuel injection quantity for two injections, pilot injection timing and main injection timing. Both forms of optimization proved effective for optimizing engine operation. The PSO-GA hybrid was able to find a superior solution to that of ABC within fewer engine runs. Both solutions call for high exhaust gas recirculation to reduce oxide of nitrogen (NOx) emissions while also moving pilot and main fuel injections to near top dead center for improved tradeoffs between NOx and particulate matter.

Development and Testing of a 6-Cylinder HCCI Engine for Distributed Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flowers, D L; Martinez-Frias, J; Espinosa-Loza, F

2005-07-12

This paper describes the technical approach for converting a Caterpillar 3406 natural gas spark ignited engine into HCCI mode. The paper describes all stages of the process, starting with a preliminary analysis that determined that the engine can be operated by preheating the intake air with a heat exchanger that recovers energy from the exhaust gases. This heat exchanger plays a dual role, since it is also used for starting the engine. For start-up, the heat exchanger is preheated with a natural gas burner. The engine is therefore started in HCCI mode, avoiding the need to handle the potentially difficultmore » transition from SI or diesel mode to HCCI. The fueling system was modified by replacing the natural gas carburetor with a liquid petroleum gas (LPG) carburetor. This modification sets an upper limit for the equivalence ratio at {phi} {approx} 0.4, which is ideal for HCCI operation and guarantees that the engine will not fail due to knock. Equivalence ratio can be reduced below 0.4 for low load operation with an electronic control valve. Intake boosting has been a challenge, as commercially available turbochargers are not a good match for the engine, due to the low HCCI exhaust temperature. Commercial introduction of HCCI engines for stationary power will therefore require the development of turbochargers designed specifically for this mode of operation. Considering that no appropriate off-the-shelf turbocharger for HCCI engines exists at this time, we are investigating mechanical supercharging options, which will deliver the required boost pressure (3 bar absolute intake) at the expense of some reduction in the output power and efficiency. An appropriate turbocharger can later be installed for improved performance when it becomes available or when a custom turbocharger is developed. The engine is now running in HCCI mode and producing power in an essentially naturally aspirated mode. Current work focuses on developing an automatic controller for obtaining consistent combustion in the 6 cylinders. The engine will then be tested for 1000 hours to demonstrate durability. This paper presents intermediate progress towards development of an HCCI engine for stationary power generation and next steps towards achieving the project goals.« less

Study of advanced rotary combustion engines for commuter aircraft

NASA Technical Reports Server (NTRS)

Berkowitz, M.; Jones, C.; Myers, D.

1983-01-01

Performance, weight, size, and maintenance data for advanced rotary aircraft engines suitable for comparative commuter aircraft system evaluation studies of alternate engine candidates are provided. These are turbocharged, turbocompounded, direct injected, stratified charge rotary engines. Hypothetical engines were defined (an RC4-74 at 895 kW and an RC6-87 at 1490 kW) based on the technologies and design approaches used in the highly advanced engine of a study of advanced general aviation rotary engines. The data covers the size range of shaft power from 597 kW (800 hp) to 1865 kW (2500 hp) and is in the form of drawings, tables, curves and written text. These include data on internal geometry and configuration, installation information, turbocharging and turbocompounding arrangements, design features and technologies, engine cooling, fuels, scaling for weight size BSFC and heat rejection for varying horsepower, engine operating and performance data, and TBO and maintenance requirements. The basic combustion system was developed and demonstrated; however the projected power densities and performance efficiencies require increases in engine internal pressures, thermal loading, and rotative speed.

An LPV Adaptive Observer for Updating a Map Applied to an MAF Sensor in a Diesel Engine

PubMed Central

Liu, Zhiyuan; Wang, Changhui

2015-01-01

In this paper, a new method for mass air flow (MAF) sensor error compensation and an online updating error map (or lookup table) due to installation and aging in a diesel engine is developed. Since the MAF sensor error is dependent on the engine operating point, the error model is represented as a two-dimensional (2D) map with two inputs, fuel mass injection quantity and engine speed. Meanwhile, the 2D map representing the MAF sensor error is described as a piecewise bilinear interpolation model, which can be written as a dot product between the regression vector and parameter vector using a membership function. With the combination of the 2D map regression model and the diesel engine air path system, an LPV adaptive observer with low computational load is designed to estimate states and parameters jointly. The convergence of the proposed algorithm is proven under the conditions of persistent excitation and given inequalities. The observer is validated against the simulation data from engine software enDYNA provided by Tesis. The results demonstrate that the operating point-dependent error of the MAF sensor can be approximated acceptably by the 2D map from the proposed method. PMID:26512675

Durability Testing of Biomass Based Oxygenated Fuel Components in a Compression Ignition Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ratcliff, Matthew A; McCormick, Robert L; Baumgardner, Marc E.

Blending cellulosic biofuels with traditional petroleum-derived fuels results in transportation fuels with reduced carbon footprints. Many cellulosic fuels rely on processing methods that produce mixtures of oxygenates which must be upgraded before blending with traditional fuels. Complete oxygenate removal is energy-intensive and it is likely that such biofuel blends will necessarily contain some oxygen content to be economically viable. Previous work by our group indicated that diesel fuel blends with low levels (<4%-vol) of oxygenates resulted in minimal negative effects on short-term engine performance and emissions. However, little is known about the long-term effects of these compounds on engine durabilitymore » issues such as the impact on fuel injection, in-cylinder carbon buildup, and engine oil degradation. In this study, four of the oxygenated components previously tested were blended at 4%-vol in diesel fuel and tested with a durability protocol devised for this work consisting of 200 hrs of testing in a stationary, single-cylinder, Yanmar diesel engine operating at constant load. Oil samples, injector spray patterns, and carbon buildup from the injector and cylinder surfaces were analyzed. It was found that, at the levels tested, these fuels had minimal impact on the overall engine operation, which is consistent with our previous findings.« less

Emission Studies in CI Engine using LPG and Palm Kernel Methyl Ester as Fuels and Di-ethyl Ether as an Additive

NASA Astrophysics Data System (ADS)

Dora, Nagaraju; Jothi, T. J. Sarvoththama

2018-05-01

The present study investigates the effectiveness of using di-ethyl ether (DEE) as the fuel additive in engine performance and emissions. Experiments are carried out in a single cylinder four stroke diesel engine at constant speed. Two different fuels namely liquefied petroleum gas (LPG) and palm kernel methyl ester (PKME) are used as primary fuels with DEE as the fuel additive. LPG flow rates of 0.6 and 0.8 kg/h are considered, and flow rate of DEE is varied to maintain the constant engine speed. In case of PKME fuel, it is blended with diesel in the latter to the former ratio of 80:20, and DEE is varied in the volumetric proportion of 1 and 2%. Results indicate that for the engine operating in LPG-DEE mode at 0.6 kg/h of LPG, the brake thermal efficiency is lowered by 26%; however, NOx is subsequently reduced by around 30% compared to the engine running with only diesel fuel at 70% load. Similarly, results of PKME blended fuel showed a drastic reduction in the NOx and CO emissions. In these two modes of operation, DEE is observed to be significant fuel additive regarding emissions reduction.

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.

Anomaly Detection Techniques with Real Test Data from a Spinning Turbine Engine-Like Rotor

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Woike, Mark R.; Oza, Nikunj C.; Matthews, Bryan L.

2012-01-01

Online detection techniques to monitor the health of rotating engine components are becoming increasingly attractive to aircraft engine manufacturers in order to increase safety of operation and lower maintenance costs. Health monitoring remains a challenge to easily implement, especially in the presence of scattered loading conditions, crack size, component geometry, and materials properties. The current trend, however, is to utilize noninvasive types of health monitoring or nondestructive techniques to detect hidden flaws and mini-cracks before any catastrophic event occurs. These techniques go further to evaluate material discontinuities and other anomalies that have grown to the level of critical defects that can lead to failure. Generally, health monitoring is highly dependent on sensor systems capable of performing in various engine environmental conditions and able to transmit a signal upon a predetermined crack length, while acting in a neutral form upon the overall performance of the engine system.

Large-Scale Operations Management Test of Use of the White Amur for Control of Problem Aquatic Plants. Report 2. First Year Poststocking Results. Volume IV. Nitrogen and Phosphorus Dynamics of the Lake Conway Ecosystem: Loading Budgets and a Dynamic Hydrologic Phosphorus Model.

DTIC Science & Technology

1982-08-01

AD-AIA 700 FLORIDA UN1V GAINESVILLE DEPT OF ENVIRONMENTAL ENGIN -ETC F/G 6/6 LARGE-SCALE OPERATIONS MANAGEMENT TEST OF USE OF THE WHITE AMOR--ENL...Conway ecosystem and is part of the Large- Scale Operations Management Test (LSOMT) of the Aquatic Plant Control Research Program (APCRP) at the WES...should be cited as follows: Blancher, E. C., II, and Fellows, C. R. 1982. "Large-Scale Operations Management Test of Use of the White Amur for Control

Sea level side loads in high-area-ratio rocket engines

NASA Technical Reports Server (NTRS)

Nave, L. H.; Coffey, G. A.

1973-01-01

An empirical separation and side load model to obtain applied aerodynamic loads has been developed based on data obtained from full-scale J-2S (265K-pound-thrust engine with an area ratio of 40:1) engine and model testing. Experimental data include visual observations of the separation patterns that show the dynamic nature of the separation phenomenon. Comparisons between measured and applied side loads are made. Correlations relating the separation location to the applied side loads and the methods used to determine the separation location are given.

Cabin-fuselage-wing structural design concept with engine installation

NASA Technical Reports Server (NTRS)

Ariotti, Scott; Garner, M.; Cepeda, A.; Vieira, J.; Bolton, D.

1993-01-01

The purpose of this project is to provide a fuselage structural assembly and wing structural design that will be able to withstand the given operational parameters and loads provided by Federal Aviation Regulation Part 23 (FAR 23) and the Statement of Work (SOW). The goal is to provide a durable lightweight structure that will transfer the applied loads through the most efficient load path. Areas of producibility and maintainability of the structure will also be addressed. All of the structural members will also meet or exceed the desired loading criteria, along with providing adequate stiffness, reliability, and fatigue life as stated in the SOW. Considerations need to be made for control system routing and cabin heating/ventilation. The goal of the wing structure and carry through structure is also to provide a simple, lightweight structure that will transfer the aerodynamic forces produced by the wing, tailboom, and landing gear. These forces will be channeled through various internal structures sized for the pre-determined loading criteria. Other considerations were to include space for flaps, ailerons, fuel tanks, and electrical and control system routing. The difficulties encountered in the fuselage design include expanding the fuselage cabin to accept a third occupant in a staggered configuration and providing ample volume for their safety. By adding a third person the CG of aircraft will move forward so the engine needs to be moved aft to compensate for the difference in the moment. This required the provisions of a ring frame structure for the new position of the engine mount. The difficulties encountered in the wing structural design include resizing the wing for the increased capacity and weight, and compensating for a large torsion produced by the tail boom by placing a great number of stiffeners inside the boom, which will result in the relocation of the fuel tank. Finally, an adequate carry through structure for the wing and fuselage interface will be designed to effectively transmit loads through the fuselage.

The composite load spectra project

NASA Technical Reports Server (NTRS)

Newell, J. F.; Ho, H.; Kurth, R. E.

1990-01-01

Probabilistic methods and generic load models capable of simulating the load spectra that are induced in space propulsion system components are being developed. Four engine component types (the transfer ducts, the turbine blades, the liquid oxygen posts and the turbopump oxidizer discharge duct) were selected as representative hardware examples. The composite load spectra that simulate the probabilistic loads for these components are typically used as the input loads for a probabilistic structural analysis. The knowledge-based system approach used for the composite load spectra project provides an ideal environment for incremental development. The intelligent database paradigm employed in developing the expert system provides a smooth coupling between the numerical processing and the symbolic (information) processing. Large volumes of engine load information and engineering data are stored in database format and managed by a database management system. Numerical procedures for probabilistic load simulation and database management functions are controlled by rule modules. Rules were hard-wired as decision trees into rule modules to perform process control tasks. There are modules to retrieve load information and models. There are modules to select loads and models to carry out quick load calculations or make an input file for full duty-cycle time dependent load simulation. The composite load spectra load expert system implemented today is capable of performing intelligent rocket engine load spectra simulation. Further development of the expert system will provide tutorial capability for users to learn from it.

Assessment of crack growth in a space shuttle main engine first-stage, high-pressure fuel turbopump blade

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali

1993-01-01

A two-dimensional finite element fracture mechanics analysis of a space shuttle main engine (SSME) turbine blade firtree was performed using the MARC finite element code. The analysis was conducted under combined effects of thermal and mechanical loads at steady-state conditions. Data from a typical engine stand cycle of the SSME were used to run a heat transfer analysis and, subsequently, a thermal structural fracture mechanics analysis. Temperature and stress contours for the firtree under these operating conditions were generated. High stresses were found at the firtree lobes where crack initiation was triggered. A life assessment of the firtree was done by assuming an initial and a final crack size.

Unbalance response of a two spool gas turbine engine with squeeze film bearings

NASA Technical Reports Server (NTRS)

Gunter, E. J.; Barrett, L. E.; Li, D. F.

1981-01-01

This paper presents a dynamic analysis of a two-spool gas turbine helicopter engine incorporating intershaft rolling element bearings between the gas generator and power turbine rotors. The analysis includes the nonlinear effects of a squeeze film bearing incorporated on the gas generator rotor. The analysis includes critical speeds and forced response of the system and indicates that substantial dynamic loads may be imposed on the intershaft bearings and main bearing supports with an improperly designed squeeze film bearing. A comparison of theoretical and experimental gas generator rotor response is presented illustrating the nonlinear characteristics of the squeeze film bearing. It was found that large intershaft bearing forces may occur even though the engine is not operating at a resonant condition.

The convertible engine: A dual-mode propulsion system

NASA Technical Reports Server (NTRS)

Mcardle, Jack G.

1988-01-01

A variable inlet guide vane (VIGV) convertible engine that could be used to power future high-speed rotorcraft was tested on an outdoor stand. The engine ran stably and smoothly in the turbofan, turboshaft, and dual (combined fan and shaft) power modes. In the turbofan mode with the VIGV open, fuel consumption was comparable to that of a conventional turbofan engine. In the turboshaft mode with the VIGV closed, fuel consumption was higher than that of present turboshaft engines because power was wasted in churning fan-tip air flow. In dynamic performance tests with a specially built digital engine control and using a waterbrake dynamometer for shaft load, the engine responded effectively to large steps in thrust command and shaft torque. Previous mission analyses of a conceptual X-wing rotorcraft capable of 400-knot cruise speed were revised to account for more fan-tip churning power loss that was originally estimated. The calculations confirm that using convertible engines rather than separate life and cruise engines would result in a smaller, lighter craft with lower fuel use and direct operating cost.

Outdoor test stand performance of a convertible engine with variable inlet guide vanes for advanced rotorcraft propulsion

NASA Technical Reports Server (NTRS)

Mcardle, Jack G.

1986-01-01

A variable inlet guide van (VIGV) type convertible engine that could be used to power future high-speed rotorcraft was tested on an outdoor stand. The engine ran stably and smoothly in the turbofan, turboshaft, and dual (combined fan and shaft) power modes. In the turbofan mode with the VIGV open fuel consumption was comparable to that of a conventional turbofan engine. In the turboshaft mode with the VIGV closed fuel consumption was higher than that of present turboshaft engines because power was wasted in churning fan-tip airflow. In dynamic performance tests with a specially built digital engine control and using a waterbrake dynamometer for shaft load, the engine responded effectively to large steps in thrust command and shaft torque. Previous mission analyses of a conceptual X-wing rotorcraft capable of 400-knot cruise speed were revised to account for more fan-tip churning power loss than was originally estimated. The new calculations confirm that using convertible engines rather than separate lift and cruise engines would result in a smaller, lighter craft with lower fuel use and direct operating cost.

A new technique for thermodynamic engine modeling

NASA Astrophysics Data System (ADS)

Matthews, R. D.; Peters, J. E.; Beckel, S. A.; Shizhi, M.

1983-12-01

Reference is made to the equations given by Matthews (1983) for piston engine performance, which show that this performance depends on four fundamental engine efficiencies (combustion, thermodynamic cycle or indicated thermal, volumetric, and mechanical) as well as on engine operation and design parameters. This set of equations is seen to suggest a different technique for engine modeling; that is, that each efficiency should be modeled individually and the efficiency submodels then combined to obtain an overall engine model. A simple method for predicting the combustion efficiency of piston engines is therefore required. Various methods are proposed here and compared with experimental results. These combustion efficiency models are then combined with various models for the volumetric, mechanical, and indicated thermal efficiencies to yield three different engine models of varying degrees of sophistication. Comparisons are then made of the predictions of the resulting engine models with experimental data. It is found that combustion efficiency is almost independent of load, speed, and compression ratio and is not strongly dependent on fuel type, at least so long as the hydrogen-to-carbon ratio is reasonably close to that for isooctane.

SSME/side loads analysis for flight configuration, revision A. [structural analysis of space shuttle main engine under side load excitation

NASA Technical Reports Server (NTRS)

Holland, W.

1974-01-01

This document describes the dynamic loads analysis accomplished for the Space Shuttle Main Engine (SSME) considering the side load excitation associated with transient flow separation on the engine bell during ground ignition. The results contained herein pertain only to the flight configuration. A Monte Carlo procedure was employed to select the input variables describing the side load excitation and the loads were statistically combined. This revision includes an active thrust vector control system representation and updated orbiter thrust structure stiffness characteristics. No future revisions are planned but may be necessary as system definition and input parameters change.

Dynamic and Transient Performance of Turbofan/Turboshaft Convertible Engine With Variable Inlet Guide Vanes

NASA Technical Reports Server (NTRS)

McArdle, Jack G.; Barth, Richard L.; Wenzel, Leon M.; Biesiadny, Thomas J.

1996-01-01

A convertible engine called the CEST TF34, using the variable inlet guide vane method of power change, was tested on an outdoor stand at the NASA Lewis Research Center with a waterbrake dynamometer for the shaft load. A new digital electronic system, in conjunction with a modified standard TF34 hydromechanical fuel control, kept engine operation stable and safely within limits. All planned testing was completed successfully. Steady-state performance and acoustic characteristics were reported previously and are referenced. This report presents results of transient and dynamic tests. The transient tests measured engine response to several rapid changes in thrust and torque commands at constant fan (shaft) speed. Limited results from dynamic tests using the pseudorandom binary noise technique are also presented. Performance of the waterbrake dynamometer is discussed in an appendix.

Experimental analysis of IMEP in a rotary combustion engine. [Indicated Mean Effective Pressure

NASA Technical Reports Server (NTRS)

Schock, H. J.; Rice, W. J.; Meng, P. R.

1981-01-01

This experimental work demonstrates the use of a NASA designed, real time Indicated Mean Effective Pressure (IMEP) measurement system which will be used to judge proposed improvements in cycle efficiency of a rotary combustion engine. This is the first self-contained instrument that is capable of making real time measurements of IMEP in a rotary engine. Previous methods used require data recording and later processing using a digital computer. The unique features of this instrumentation include its ability to measure IMEP on a cycle by cycle, real time basis and the elimination of the need to differentiate the volume function in real time. Measurements at two engine speeds (2000 and 3000 RPM) and a full range of loads are presented, although the instrument was designed to operate to speeds of 9000 RPM.

76 FR 44245 - Special Conditions: Gulfstream Model GVI Airplane; Limit Engine Torque Loads for Sudden Engine...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-25

... Conditions No. 25-441-SC] Special Conditions: Gulfstream Model GVI Airplane; Limit Engine Torque Loads for... transient dynamic loads resulting from: (a) The loss of any fan, compressor, or turbine blade; and (b...;Federal Register / Vol. 76, No. 142 / Monday, July 25, 2011 / Rules and Regulations#0;#0; [[Page 44245...

Ocean Engineering Studies Compiled 1991. Volume 9. External Pressure Housing - Conrete

DTIC Science & Technology

1991-01-01

by inserts of different rigidities would thus be obtained. Table 1. Description of Concrete Sphere Models and Test...relationship between the insert’s rigidity and the strain increase in its vicinity. Planned investigation by NCEL employing photoelastic analysis of models of ... structural , in which only the load -carrying ability of the structure was checked. In the operational tests, the small-scale model habitat

Design and evaluation of a 3 million DN series-hybrid thrust bearing. [stability tests and fatigue tests

NASA Technical Reports Server (NTRS)

Scibbe, H. W.; Winn, L. W.; Eusepi, M.

1976-01-01

The bearing, consisting of a 150-mm ball bearing and a centrifugally actuated, conical, fluid-film bearing, was fatigue tested. Test conditions were representative of a mainshaft ball bearing in a gas turbine engine operating at maximum thrust load to simulate aircraft takeoff conditions. Tests were conducted up to 16000 rpm and at this speed an axial load of 15568 newtons (3500 lb) was safely supported by the hybrid bearing system. Through the series-hybrid bearing principle, the effective ball bearing speed was reduced to approximately one-half of the shaft speed. It was concluded that a speed reduction of this magnitude results in a ten-fold increase in the ball bearing fatigue life. A successful evaluation of fluid-film bearing lubricant supply failure was performed repeatedly at an operating speed of 10,000 rpm. A complete and smooth changeover to full-scale ball bearing operation was effected when the oil supply to the fluid-film bearing was cut off. Reactivation of the fluid-film oil supply system resulted in a flawless return to the original mode of hybrid operation.

Rocket Engine Nozzle Side Load Transient Analysis Methodology: A Practical Approach

NASA Technical Reports Server (NTRS)

Shi, John J.

2005-01-01

At the sea level, a phenomenon common with all rocket engines, especially for a highly over-expanded nozzle, during ignition and shutdown is that of flow separation as the plume fills and empties the nozzle, Since the flow will be separated randomly. it will generate side loads, i.e. non-axial forces. Since rocket engines are designed to produce axial thrust to power the vehicles, it is not desirable to be excited by non-axial input forcing functions, In the past, several engine failures were attributed to side loads. During the development stage, in order to design/size the rocket engine components and to reduce the risks, the local dynamic environments as well as dynamic interface loads have to be defined. The methodology developed here is the way to determine the peak loads and shock environments for new engine components. In the past it is not feasible to predict the shock environments, e.g. shock response spectra, from one engine to the other, because it is not scaleable. Therefore, the problem has been resolved and the shock environments can be defined in the early stage of new engine development. Additional information is included in the original extended abstract.

LPG as a Fuel for Diesel Engines-Experimental Investigations

NASA Astrophysics Data System (ADS)

Cristian Nutu, Nikolaos; Pana, Constantin; Negurescu, Niculae; Cernat, Alexandru; Mirica, Ionel

2017-10-01

The main objective of the paper is to reduce the pollutant emissions of a compression ignition engine, fuelling the engine with liquefied petroleum gas (LPG), aiming to maintain the energetic performances of the engine. To optimise the engine operation a corelation between the substitute ratio of the diesel fuel with LPG and the adjustments for the investigated regimens must be made in order to limit the maximum pressure and smoke level, knock and rough engine functioning, fuel consumption and the level of the pollutant emissions. The test bed situated in the Thermotechnics, Engines, Thermal Equipments and Refrigeration Instalations Department was adapted to be fuelled with liquefied petroleum gas. A conventional LPG fuelling instalation was adopted, consisting of a LPG tank, a vaporiser, conections between the tank and the vaporiser and a valve to adjust the gaseous fuel flow. Using the diesel-gas methode, in the intake manifold of the engine is injected LPG in gaseous aggregation state and the airr-LPG homogeneous mixture is ignited from the flame appeared in the diesel fuel sprays. To maintain the engine power at the same level like in the standard case of fuelling only with diesel fuel, for each investigated operate regimen the diesel fuel dose was reduced, being energetically substituted with LPG. The engine used for experimental investigations is a turbocharged truck diesel engine with a 10.34 dm3 displacement. The investigated working regimen was 40% load and 1750 rpm and the energetic substitute ratios of the diesel fuel with LPG was situated between [0-25%].

The role of mechanical loading in ligament tissue engineering.

PubMed

Benhardt, Hugh A; Cosgriff-Hernandez, Elizabeth M

2009-12-01

Tissue-engineered ligaments have received growing interest as a promising alternative for ligament reconstruction when traditional transplants are unavailable or fail. Mechanical stimulation was recently identified as a critical component in engineering load-bearing tissues. It is well established that living tissue responds to altered loads through endogenous changes in cellular behavior, tissue organization, and bulk mechanical properties. Without the appropriate biomechanical cues, new tissue formation lacks the necessary collagenous organization and alignment for sufficient load-bearing capacity. Therefore, tissue engineers utilize mechanical conditioning to guide tissue remodeling and improve the performance of ligament grafts. This review provides a comparative analysis of the response of ligament and tendon fibroblasts to mechanical loading in current bioreactor studies. The differential effect of mechanical stimulation on cellular processes such as protease production, matrix protein synthesis, and cell proliferation is examined in the context of tissue engineering design.

Rotor-generated unsteady aerodynamic interactions in a 1½ stage compressor

NASA Astrophysics Data System (ADS)

Papalia, John J.

Because High Cycle Fatigue (HCF) remains the predominant surprise failure mode in gas turbine engines, HCF avoidance design systems are utilized to identify possible failures early in the engine development process. A key requirement of these analyses is accurate determination of the aerodynamic forcing function and corresponding airfoil unsteady response. The current study expands the limited experimental database of blade row interactions necessary for calibration of predictive HCF analyses, with transonic axial-flow compressors of particular interest due to the presence of rotor leading edge shocks. The majority of HCF failures in aircraft engines occur at off-design operating conditions. Therefore, experiments focused on rotor-IGV interactions at off-design are conducted in the Purdue Transonic Research Compressor. The rotor-generated IGV unsteady aerodynamics are quantified when the IGV reset angle causes the vane trailing edge to be nearly aligned with the rotor leading edge shocks. A significant vane response to the impulsive static pressure perturbation associated with a shock is evident in the point measurements at 90% span, with details of this complex interaction revealed in the corresponding time-variant vane-to-vane flow field data. Industry wide implementation of Controlled Diffusion Airfoils (CDA) in modern compressors motivated an investigation of upstream propagating CDA rotor-generated forcing functions. Whole field velocity measurements in the reconfigured Purdue Transonic Research Compressor along the design speedline reveal steady loading had a considerable effect on the rotor shock structure. A detached rotor leading edge shock exists at low loading, with an attached leading edge and mid-chord suction surface normal shock present at nominal loading. These CDA forcing functions are 3--4 times smaller than those generated by the baseline NACA 65 rotor at their respective operating points. However, the IGV unsteady aerodynamic response to the CDA forcing functions remains significant. The intra-vane transport of NACA 65 and CDA rotor wakes is also observed within the time-variant passage velocity data. In general, the wake width and decay rate increase with rotor speed and compressor steady loading respectively.

Investigation of the Impact of Fuel Properties on Particulate Number Emission of a Modern Gasoline Direct Injection Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCormick, Robert L; Fioroni, Gina; Fatouraie, Mohammad

Gasoline Direct Injection (GDI) has become the preferred technology for spark-ignition engines resulting in greater specific power output and lower fuel consumption, and consequently reduction in CO2 emission. However, GDI engines face a substantial challenge in meeting new and future emission limits, especially the stringent particle number (PN) emissions recently introduced in Europe and China. Studies have shown that the fuel used by a vehicle has a significant impact on engine out emissions. In this study, nine fuels with varying chemical composition and physical properties were tested on a modern turbo-charged side-mounted GDI engine with design changes to reduce particulatemore » emissions. The fuels tested included four fuels meeting US certification requirements; two fuels meeting European certification requirements; and one fuel meeting China 6 certification requirements being proposed at the time of this work. Two risk safeguard fuels (RSG), representing the properties of worst case market fuels in Europe and China, were also included. The particle number concentration of the solid particulates was measured in the engine-out exhaust flow at steady state engine operations with load and speed sweeps, and semi-transient load steps. The test results showed a factor of 6 PN emission difference among all certification fuels tested. Combined with detailed fuel analyses, this study evaluated important factors (such as oxygenates, carbon chain length and thermo-physical properties) that cause PN emissions which were not included in PMI index. A linear regression was performed to develop a PN predictive model which showed improved fitting quality than using PMI.« less

Biodiesel Impact on Engine Lubricant Dilution During Active Regeneration of Aftertreatment Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, X.; Williams, A.; Christensen, E.

Experiments were conducted with ultra low sulfur diesel (ULSD) and 20% biodiesel blends (B20) to compare lube oil dilution levels and lubricant properties for systems using late in-cylinder fuel injection for aftertreatment regeneration. Lube oil dilution was measured by gas chromatography (GC) following ASTM method D3524 to measure diesel content, by Fourier transform infrared (FTIR) spectrometry following a modified ASTM method D7371 to measure biodiesel content, and by a newly developed back-flush GC method that simultaneously measures both diesel and biodiesel. Heavy-duty (HD) engine testing was conducted on a 2008 6.7L Cummins ISB equipped with a diesel oxidation catalyst (DOC)more » and diesel particle filter (DPF). Stage one of engine testing consisted of 10 consecutive repeats of a forced DPF regeneration event. This continuous operation with late in-cylinder fuel injection served as a method to accelerate lube-oil dilution. Stage two consisted of 16 hours of normal engine operation over a transient test cycle, which created an opportunity for any accumulated fuel in the oil sump to evaporate. Light duty (LD) vehicle testing was conducted on a 2010 VW Jetta equipped with DOC, DPF and a NOx storage catalyst (NSC). Vehicle testing comprised approximately 4,000 miles of operation on a mileage-accumulation dynamometer (MAD) using the U.S. Environmental Protection Agency's Highway Fuel Economy Cycle because of the relatively low engine oil and exhaust temperatures, and high DPF regeneration frequency of this cycle relative to other cycles examined. Comparison of the lube oil dilution analysis methods suggests that D3524 does not measure dilution by biodiesel. The new back-flush GC method provided analysis for both diesel and biodiesel, in a shorter time and with lower detection limit. Thus all lube oil dilution results in this paper are based on this method. Analysis of the HD lube-oil samples showed only 1.5% to 1.6% fuel dilution for both fuels during continuous operation under DPF regeneration events. During the second stage of HD testing, the ULSD lube-oil dilution levels fell from 1.5% to 0.8%, while for B20, lube-oil dilution levels fell from 1.6% to 1.0%, but the fuel in the oil was 36% biodiesel. For the LD vehicle tests, the frequency of DPF regeneration events was observed to be the same for both ULSD and B20. No significant difference between the two fuels' estimated soot loading was detected by the engine control unit (ECU), although a 23% slower rate of increase in differential pressure across DPF was observed with B20. It appears that the ECU estimated soot loading is based on the engine map, not taking advantage of the lower engine-out particulate matter from the use of biodiesel. After 4,000 miles of LD vehicle operation with ULSD, fuel dilution in the lube-oil samples showed total dilution levels of 4.1% diesel. After 4,000 miles of operation with B20, total fuel in oil dilution levels were 6.7% consisting of 3.6% diesel fuel and 3.1% biodiesel. Extrapolation to the 10,000-mile oil drain interval with B20 suggests that the total fuel content in the oil could reach 12%, compared to 5% for operation on ULSD. Analysis of the oil samples also included measurement of total acid number, total base number, viscosity, soot, metals and wear scar; however, little difference in these parameters was noted.« less

Free-Piston Stirling Convertor Controller Development at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Regan, Timothy

2004-01-01

The free-piston Stirling convertor end-to-end modeling effort at NASA Glenn Research Center (GRC) has produced a software-based test bed in which free-piston Stirling convertors can be simulated and evaluated. The simulation model includes all the components of the convertor - the Stirling cycle engine, linear alternator, controller, and load. This paper is concerned with controllers. It discusses three controllers that have been studied using this model. Case motion has been added to the model recently so that effects of differences between convertor components can be simulated and ameliorative control engineering techniques can be developed. One concern when applying a system comprised of interconnected mass-spring-damper components is to prevent operation in any but the intended mode. The design mode is the only desired mode of operation, but all other modes are considered in controller design.

Calculation of the Strip Foundation on Solid Elastic Base, Taking into Account the Karst Collapse

NASA Astrophysics Data System (ADS)

Sharapov, R.; Lodigina, N.

2017-07-01

Karst processes greatly complicate the construction and operation of buildings and structures. Due to the karstic deformations at different times there have been several major accidents, which analysis showed that in all cases the fundamental errors committed at different stages of building development: site selection, engineering survey, design, construction or operation of the facilities. Theory analysis of beams on elastic foundation is essential in building practice. Specialist engineering facilities often have to resort to multiple designing in finding efficient forms of construction of these facilities. In work the calculation of stresses in cross-sections of the strip foundation evenly distributed load in the event of karst. A comparison of extreme stress in the event of karst and without accounting for the strip foundation as a beam on an elastic foundation.

Spherical Joint Piston and Connecting Rod Developed

NASA Technical Reports Server (NTRS)

1996-01-01

Under an interagency agreement with the Department of Energy, the NASA Lewis Research Center manages a Heavy-Duty Diesel Engine Technology (HDET) research program. The overall program objectives are to reduce fuel consumption through increased engine efficiency, reduce engine exhaust emissions, and provide options for the use of alternative fuels. The program is administered with a balance of research contracts, university research grants, and focused in-house research. The Cummins Engine Company participates in the HDET program under a cost-sharing research contract. Cummins is researching and developing in-cylinder component technologies for heavy-duty diesel engines. An objective of the Cummins research is to develop technologies for a low-emissions, 55-percent thermal efficiency (LE-55) engine. The best current-production engines in this class achieve about 46-percent thermal efficiency. Federal emissions regulations are driving this technology. Regulations for heavy duty diesel engines were tightened in 1994, more demanding emissions regulations are scheduled for 1998, and another step is planned for 2002. The LE-55 engine emissions goal is set at half of the 1998 regulation level and is consistent with plans for 2002 emissions regulations. LE-55 engine design requirements to meet the efficiency target dictate a need to operate at higher peak cylinder pressures. A key technology being developed and evaluated under the Cummins Engine Company LE-55 engine concept is the spherical joint piston and connecting rod. Unlike conventional piston and connecting rod arrangements which are joined by a pin forming a hinged joint, the spherical joint piston and connecting rod use a ball-and-socket joint. The ball-and-socket arrangement enables the piston to have an axisymmetric design allowing rotation within the cylinder. The potential benefits of piston symmetry and rotation are reduced scuffing, improved piston ring sealing, improved lubrication, mechanical and thermal load symmetry, reduced bearing stresses, reduced running clearances, and reduced oil consumption. The spherical joint piston is a monolithic, squeeze-cast, fiber-reinforced aluminum piston. The connecting rod has a ball end that seats on a spherical saddle within the piston and is retained by a pair of aluminum bronze holder rings. The holder rings are secured by a threaded ring that mates with the piston. As part of the ongoing research and development activity, the Cummins Engine Company successfully completed a 100-hr test of the spherical joint piston and connecting rod at LE- 55 peak steady-state engine conditions. In addition, a 100-hr transient cycle test that varied engine conditions between LE-55 no-load and LE-55 full-load was successfully completed.

3D Printing and Biofabrication for Load Bearing Tissue Engineering.

PubMed

Jeong, Claire G; Atala, Anthony

2015-01-01

Cell-based direct biofabrication and 3D bioprinting is becoming a dominant technological platform and is suggested as a new paradigm for twenty-first century tissue engineering. These techniques may be our next step in surpassing the hurdles and limitations of conventional scaffold-based tissue engineering, and may offer the industrial potential of tissue engineered products especially for load bearing tissues. Here we present a topically focused review regarding the fundamental concepts, state of the art, and perspectives of this new technology and field of biofabrication and 3D bioprinting, specifically focused on tissue engineering of load bearing tissues such as bone, cartilage, osteochondral and dental tissue engineering.

Effects of injection parameters, boost, and swirl ratio on gasoline compression ignition operation at idle and low-load conditions

DOE PAGES

Kodavasal, Janardhan; Kolodziej, Christopher P.; Ciatti, Stephen A.; ...

2016-11-03

In this study, we study the effects of injector nozzle inclusion angle, injection pressure, boost, and swirl ratio on gasoline compression ignition combustion. Closed-cycle computational fluid dynamics simulations using a 1/7th sector mesh representing a single cylinder of a four-cylinder 1.9 L diesel engine, operated in gasoline compression ignition mode with 87 anti-knock index (AKI) gasoline, were performed. Two different operating conditions were studied—the first is representative of idle operation (4 mg fuel/cylinder/cycle, 850 r/min), and the second is representative of a low-load condition (10 mg fuel/cylinder/cycle, 1500 r/min). The mixture preparation and reaction space from the simulations were analyzedmore » to gain insights into the effects of injection pressure, nozzle inclusion angle, boost, and swirl ratio on achieving stable low-load to idle gasoline compression ignition operation. It was found that narrower nozzle inclusion angles allow for more reactivity or propensity to ignition (determined qualitatively by computing constant volume ignition delays) and are suitable over a wider range of injection timings. Under idle conditions, it was found that lower injection pressures helped to reduce overmixing of the fuel, resulting in greater reactivity and ignitability (ease with which ignition can be achieved) of the gasoline. However, under the low-load condition, lower injection pressures did not increase ignitability, and it is hypothesized that this is because of reduced chemical residence time resulting from longer injection durations. Reduced swirl was found to maintain higher in-cylinder temperatures through compression, resulting in better ignitability. It was found that boosting the charge also helped to increase reactivity and advanced ignition timing.« less

Effects of injection parameters, boost, and swirl ratio on gasoline compression ignition operation at idle and low-load conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kodavasal, Janardhan; Kolodziej, Christopher P.; Ciatti, Stephen A.

In this study, we study the effects of injector nozzle inclusion angle, injection pressure, boost, and swirl ratio on gasoline compression ignition combustion. Closed-cycle computational fluid dynamics simulations using a 1/7th sector mesh representing a single cylinder of a four-cylinder 1.9 L diesel engine, operated in gasoline compression ignition mode with 87 anti-knock index (AKI) gasoline, were performed. Two different operating conditions were studied—the first is representative of idle operation (4 mg fuel/cylinder/cycle, 850 r/min), and the second is representative of a low-load condition (10 mg fuel/cylinder/cycle, 1500 r/min). The mixture preparation and reaction space from the simulations were analyzedmore » to gain insights into the effects of injection pressure, nozzle inclusion angle, boost, and swirl ratio on achieving stable low-load to idle gasoline compression ignition operation. It was found that narrower nozzle inclusion angles allow for more reactivity or propensity to ignition (determined qualitatively by computing constant volume ignition delays) and are suitable over a wider range of injection timings. Under idle conditions, it was found that lower injection pressures helped to reduce overmixing of the fuel, resulting in greater reactivity and ignitability (ease with which ignition can be achieved) of the gasoline. However, under the low-load condition, lower injection pressures did not increase ignitability, and it is hypothesized that this is because of reduced chemical residence time resulting from longer injection durations. Reduced swirl was found to maintain higher in-cylinder temperatures through compression, resulting in better ignitability. It was found that boosting the charge also helped to increase reactivity and advanced ignition timing.« less