Display:

Results

Viewing 22051 to 1 of 1
1984-09-01
Technical Paper
841284
D GRUDEN, H RICHTER
1984-09-01
Technical Paper
841256
D. R. Hamburg, M. J. Throop
Vehicle chassis dynamometer tests were performed to compare predicted and measured total feedgas emissions and fuel economy for dynamic operation of an engine. In general, these tests showed that predictions based on steady-state mapping data agreed well with measured values except for NOx emissions. Subsequent engine-dynamometer tests indicated that the discrepancy between predicted and measured NOx emissions was due to competing effects of combustion chamber wall temperature and dynamic EGR time response. A technique was developed which utilized the results of a simple transient test to improve the accuracy of predicting NOx emissions when EGR time response was not a factor. The effect of degraded EGR time response on both instantaneous and total NOx emissions was also explored.
1984-09-01
Technical Paper
841288
K P MAYER
SYNOPSIS The current status and development trends of light duty diesel engines equipped with a multi-spray direct injection combustion system are described. Fuel consumption maps of a naturally aspirated and a turbocharged engine show that competitive performance and best fuel economy can be achieved. As a means for the reduction of combustion noise a “split injection device” is installed in the high pressure part of the fuel system. It permits a reduction of the amount of fuel injected during the ignition delay and consequently reduces the rate of pressure rise and maximum cylinder pressure. In addition, also a reduction of exhaust emissions is experienced. Advanced piston technology is presented as a feature for a further improvement of performance and fuel economy.
1984-09-01
Technical Paper
841286
W R WADE, P H HAVSTAD, E J OUNSTED, F H TRINKER, I J GARWIN
SYNOPSIS An experimental, uncooled, single cylinder DI Diesel engine with ceramic coated cylinder head and valves, a heat insulated steel topped piston and a short, partially stabilized zirconia cylinder liner in the area above the piston rings provided 4 to 7% improvement in fuel consumption at operating conditions typical of the EPA CVS driving cycle for light duty vehicles relative to the baseline water-cooled engine. An engine simulation model was used to explain the measured improvements in fuel consumption. Generally, the uncooled engine provided reductions in HC, NOx and particulate emissions. The trend of lower HC and NOx emissions was explained by the reduction in the amount of premixed combustion resulting from the shortened ignition delay period. The trend of lower particulate emissions was explained by an increase in the diffusion combustion rate. Reduced rates of pressure rise for the uncooled engine were projected to result in lower noise levels.
1984-09-01
Technical Paper
841292
H-P WILLUMEIT, P STEINBERG, H HÖTTING, B SCHEIBNER, W LEE
SYNOPSIS Calculating the heat balance of Otto engines one can recognize that the ratio between heat transfer and power increases in the part load range, i.e. city driving. To improve the efficiency of such engines it is necessary to reduce the quantity of heat transfer and also of friction losses. Both effects can be achieved by increasing the temperatures of the coolant and the lubricant. This gives a reduction of fuel consumption as well as of exhaust emissions. Both effects are valid even in the warm-up phase as well as under steady state operating temperature as are confirmed by the results of our experiments.
1984-09-01
Technical Paper
841297
E M GAMBERG, T A HULS
The paper describes a method of improving the air/fuel (A/F) accuracy of a single point fuel injection system that is controlled by a microprocessor. The method develops correction factors as a function of engine speed and manifold absolute pressure. The correction factors are stored in keep alive memory (KAM) for future use. The correction factors reduce A/F deviations during both open and closed loop operation thereby improving three way catalyst (TWC) efficiency and eliminating the need for a secondary air system.
1984-09-01
Technical Paper
841294
H KOBAYASHI, K YOSHIMURA, T HIRAYAMA
SYNOPSIS In this paper, feasibility of reducing knock and thereby achieving higher compression ratio in a spark ignition engine has been studied by controlling cylinder head and cylinder block coolant temperatures independently with the aim of reducing the temperature of unburnt portion of mixture during flame propagation, while preventing adverse effects on the engine performance. The study was performed using a 1.3 litre OHV water cooled engine equipped with a dual circuit cooling system. In a fundamental study at the base compression ratio of 9:1, it was found that when the cylinder head coolant temperature was lowered while maintaining the cylinder block coolant temperature at 80°C engine output at WOT was increased significantly, because of considerable knock reduction and increased charging efficiency without increase in friction torque. These results indicated a great potentiality of the dual circuit cooling system for raising the compression ratio.
1984-09-01
Technical Paper
841306
N A SCHILKE, A O DeHART, L O HEWKO, C C MATTHEWS, D J POZNIAK, S M ROHDE
Abstract The quest to improve the fuel economy of General Motors passenger cars has led to the investigation of an engine-flywheel hybrid powertrain at the GM Research Laboratories (GMR). An engine-flywheel system was designed for a compact car and its performance was predicted analytically. The system was estimated to achieve an improvement in EPA Composite fuel economy of 13% over a 1984 production compact car. This margin of improvement was judged insufficient to justify the complex drivetrain, and, therefore, a prototype system was not built. However, the current potential of engine-flywheel hybrids for GM passenger-car applications has been defined, and the technology areas requiring additional research attention have been identified.
1984-09-01
Technical Paper
841161
Tadashi Murayama, Young-taig Oh, Noboru Miyamoto, Takemi Chikahisa, Nobukazu Takagi, Koichiro Itow
The purpose of this investigation is to evaluate the feasibility of rapeseed oil and palm oil for diesel fuel substitution in a naturally aspirated D.I. diesel engine, and also to find means to reduce the carbon deposit buildup in vegetable oil combustion. In the experiments, the engine performance, exhaust gas emissions, and carbon deposits were measured for a number of fuels: rapeseed oil, palm oil, methylester of rapeseed oil, and these fuels blended with ethanol or diesel fuel with different fuel temperatures. It was found that both of the vegetable oil fuels generated an acceptable engine performance and exhaust gas emission levels for short term operation, but they caused carbon deposit buildups and sticking of piston rings after extended operation.
1984-09-01
Technical Paper
841159
Bahrain Eghbali
This paper will attempt to set forth a conceptual study of natural gas application as a vehicular fuel. In doing so it recognizes firstly, the critical importance of combustion and operational characteristics of the fuel in terms of fuelling, carburation, ignition parameters and etc. This is based on theoretical findings as well as experimental observation of different types of converted engines. Because of the strong mutual interactions involved, the value of any measure taken to optimize the engine performance should be conveniently judged within the framwork of a closed system. Then the paper examines the environmental and safety advantages of natural gas fuel, presenting a comparative emissions data with LPG and gasoline. Finally an analysis of the economics of natural gas -a direct substitute, along with data on estimated and proved reserves of the supply is given. This justifies economically also the shift to such a more decentralized, diffused and renewable energy resource.
1984-09-01
Technical Paper
841160
Takeshi Saito, Yasuhiro Daisho, Yasutoshi Aoki, Naokazu Kawase
From the viewpoint of utilizing methanol fuel in an automotive turbocharged direct-injection diesel engine, an intercooling system supplying liquid methanol has been devised and its effects on engine performance and exhaust gas emissions have been investigated. With an electronically controlled injector in this system, methanol as a supplementary fuel to diesel fuel can be injected into the intake pipe in order to intercool a hot air charge compressed by the turbocharger. It has been confirmed that especially at heavy load conditions, methanol-intercooling can yield a higher thermal efficiency, and lower NOx and smoke emissions simultaneously, compared with three other cases without using methanol: natural aspiration and the cases with and without an ordinary intercooler. However, methanol fueling must be avoided at lower loads since sacrifices in efficiency and hydrocarbon emissions are inevitably involved.
1984-09-01
Technical Paper
841195
Robert A. Frantz
Neutral rattle is a characteristic manual transmission gear rattle sound which is caused by the gears oscillating through the backlash inherent to the transmission. This oscillation is caused by engine firing impulses and the sensitivity to these impulses increases as transmission operating temperatures increase and when engine torque loads increase. Engine torque loads can be directly attributable to the rpm and the driven accessories on the engine (i.e., air conditioner, alternator, etc.). Neutral rattle can be eliminated by increasing the engine idle speed and/or by increasing the dynamic drag torque of the transmission. Each of these solutions, however, reduces the EPA mileage rating and, with the transmission, decreases cold weather shiftability performance. This paper will discuss previously used methods of removing neutral rattle and their design limitations.
1984-09-01
Technical Paper
841210
P. Dorn, A. M. Mourao
The relationship between the physical and chemical properties and performance of gasolines and diesel fuel are discussed. For gasolines, emphasis is placed on the effects of oxygenates when used as gasoline blending components. With the phase-out of leaded gasoline, the use of oxygenated blending agents is increasing in order to meet the octane demands for unleaded gasolines. Octane and volatility are the two most important quality aspects of gasolines. Oxygenates, particularly methanol and ethanol, have definite effects on these properties. The correlation between gasoline composition and its effect on other areas, e.g., emissions, water tolerance and elastomers, are also shown.
1984-09-01
Technical Paper
841225
James W. Walker, Robert F. Wiltse, Volker W. Harhaus
Two new 4.3 liter engines with 90° V-6 configurations were developed for use in Chevrolet's 1985 light duty trucks and rear wheel drive passenger cars. The new engines were optimized from the standpoint of oil sealing, performance, and fuel economy. A four-barrel quadrajet carburetor mounted on an open inlet plenum is used for truck applications and a 1×2 throttle body injection system mounted on a similar open inlet plenum is used for passenger car applications. Both engines are designed for optimum engine breathing and cylinder charging, and each requires a specific engine/emission control system. These engines are configured for even firing, have swirl inlet ports, and fast burn combustion chambers. The results obtained through the extensive engineering development program met and/or exceeded the program goals for performance, oil and coolant sealing, and fuel economy.
1984-09-01
Technical Paper
841077
Norimasa Iida, G. Takeshi Sato, Jun Hasebe
Reduction of particulate emissions from diesel engine is an important theme from the view point of air pollution. Experiments were carried out using a four-stroke single cylinder direct-injection diesel engine. A new method to measure diesel particulates has been developed. Particulates were sampled with a freezing method just behind an exhaust valve and examined through a scanning electron microscope. Shape and structure of particulates and the size distributions are measured under wide operating conditions obtained with above method. The total mass of particulate emissions was measured using a dilution tunnel sampling system. The heat release processes were analyzed using indicator diagrams and the relation between burning condition and particulate emissions were discussed, after systematic experiments under constant revolution speed of 2000 r/min for several load and injection timing conditions.
1984-09-01
Technical Paper
841080
Keiji Kishishita, Toshiaki Takatsuki, Kaoru Sato, Takehito Imai
This paper is the part II of the report of IDIS (Isuzu Dual Fuel Injection System) IDIS was applied to 5.8 liter L-6 DI diesel engine. The outlines of improved and simplified system, rate of alcohol blend, exhaust emission and performance of the engine were shown in the case of methanol blend as well as ethanol blend. For preventing the torque deviation just after start and end of alcohol blend caused by difference of calorific values between alcohol and diesel fuel, improved system with additional check valve was developed. It was confirmed that replacement of about 30% of diesel fuel by alcohol was possible without any fundamental problems. Basically no modification of the engine was required except the adoptions of new fuel tank and fuel line with low pressure pump for alcohol, some check valves and magnetic valves, a microswitch on the fuel lever and the new delivery valves with increased retraction volume.
1984-08-01
Technical Paper
840995
P. Belardini, C. Bertoli, F. E. Corcione, G. Police
The paper describes some experiments carried out on two d.i. Diesel engines running with insulated pistons. Three different thermal barriers were tested; namely, a stainless steel cup, a Si3N4 cup and a stainless steel piston crown. The combustion process was characterized by heat release calculation and ignition delay measurements. The experiments showed that the indicated efficiency is not affected by thermal insulation adoption, Nox level increases while smoke level decreases consistently.
1984-08-01
Technical Paper
840992
Gerhard F. W. Ziegler, Eberhard P. Wagner, B. Saggau, R. Maly, W. Herden
The performance of an experimental breakdown ignition (VFZ) system has been compared to a conventional transistorized coil ignition (TCI) system using a production four-cylinder engine with a compression ratio of 9:1 and a swept volume of 2.3 1. Spark ignition energy and electrode spacing were identical for both ignition systems. Results at quarter load, idling and overrun demonstrate that for optimal engine efficiency considerably less spark advance is necessary when the VFZ-system was employed since the initial combustion period is reduced substantially. This enhancement in initial flame development provides a wider range of optimization, when changing spark advance and air-fuel ratio. Therefore significant improvement are possible when focusing either on reductions of fuel consumption or pollutant emissions.
1984-08-01
Technical Paper
841053
A. C. Alkidas, R. M. Cole
Comparative experiments were performed on an experimental divided-chamber diesel engine for three coolant conditions: baseline (water at 82°C), high coolant temperature (glycol at 120°C) and a differential cooling condition where the antechamber was kept cold (water at 20°C) and the main chamber was kept hot (glycol at 120°C). High-temperature cooling was found to provide a significant brake-specific-fuel-consumption advantage at low-speed and low-load conditions and at very retarded combustion-timing conditions. In general, high coolant temperature caused an increase in hydrocarbon (HC) emissions. Lowering the antechamber surface temperature at the low-speed conditions was found to cause an increase in gaseous emissions and a reduction in smoke and particulate emissions.
HISTORICAL
1984-08-01
Standard
J254_198408
This SAE Recommended Practice establishes uniform laboratory techniques for the continuous and bag-sample measurement of various constituents in the exhaust gas of the gasoline engines installed in passenger cars and light-duty trucks. The report concentrates on the measurement of the following components in exhaust gas: hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), and nitrogen oxides (NOx). NOx is the sum of nitric oxide (NO) and nitrogen dioxide (NO2). A complete procedure for testing vehicles may be found in SAE J1094.
1984-07-01
Technical Paper
840939
Eugene H. Wissler, Sarah A. Nunneley
If thermal problems are to be avoided in both military and commercial aviation, a rational procedure is required for evaluating the effect of various environmental parameters on the condition of aircrew members. In this paper, the authors describe a computer model which has been shown to predict accurately human thermal responses over a wide range of conditions. The model allows one to evaluate the effect on aircrew members of important parameters, such as the work profile, regional and temporal variation in windspeed, temperature, and solar load, and the type of garment worn. It is also possible to simulate the use of liquid cooled garments to reduce thermal stress, and the effect of immersion in cold water. Representative applications involving three different situations are presented in the paper.
HISTORICAL
1984-06-01
Standard
J313_198406
Automotive and railroad diesel fuels, in general, are derived from petroleum refinery products which are commonly referred to as middle distillates. Middle distillates represent products which have a higher boiling range than gasoline and are obtained from fractional distillation of the crude oil or from streams from other refining processes. Finished diesel fuels represent blends of middle distillates. The properties of commercial distillate diesel fuels depend on the refinery practices employed and the nature of the crude oils from which they are derived. Thus, they may differ both with and within the region in which they are manufactured. Such fuels generally boil over a range between 163 and 371 °C (325 to 700 °F). Their makeup can represent various combinations of volatility, ignition quality, viscosity, sulfur level, gravity, and other characteristics. Additives may be used to impart special properties to the finished diesel fuel.
1984-04-01
Technical Paper
840850
Tim F. Lee
Electric forklifts have historically been used in military applications such as unloading ammunition from storage areas due to a regulation which prohibited use of gasoline, diesel, or liquid propane gas (LPG) powered engines. This regulation has been changed to allow diesel powered forklifts if inside ambient air quality remains within safe levels. Diesel powered trucks are preferred over electric power for many military applications due to operational and support advantages. A new requirement for exhaust emissions from diesel powered forklift trucks has been developed by the Army for use in procurement of warehouse diesel trucks in the 4000–6000 lb capacity size. Future procurement by the Army of warehouse diesel forklifts in the 4000 - 6000 lb size will require that engines meet the new requirement for hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOX), smoke and particulates.
1984-04-01
Technical Paper
840852
Herbert H. Dobbs
This paper discusses the impact of changing mission requirements on combat vehicle design and of new combat vehicle technology on tactics. A major shift in ground warfare tactics is predicted based on new developments in technology and historical precedents. It was written to provide an introduction and framework for the session on combat and tactical vehicles of which it was part.
1984-04-01
Technical Paper
840907
John D. States
The FMVSS were established to provide the public with uniform safety equipment and design standards based on sound research. Ongoing evaluation is essential to maintain the effectiveness and safety of FMVSS and to ensure that current technology is incorporated in standards development. Serious injury (AIS 3 or greater) reporting by NASS should be upgraded to facilitate standards evaluation and development. Although cost effectiveness is a mandated criteria for standards evaluation, the protection of human life and limb must remain the principle criteria for measuring effectiveness. A citizen's advisory panel, similar to the NMVSAC should be established to assist NHTSA in establishing priorities for standards evaluation, development and promulgation.
1984-04-01
Technical Paper
840908
Judith A. Graham, Larry D. Claxton, John J. O'Neil, David A. Otto, Bernard D. Goldstein
Mobile sources contribute to air pollution both directly and indirectly through emission of precursors to photochemical reactions. Numerous pollutants are emitted including those regulated by National Ambient Air Quality Standards (ozone, nitrogen oxides, particulate matter such as sulfuric acid, carbon monoxide, and lead) as well as others that are not regulated. These pollutants are known to cause a variety of health effects, and the effects of highest concern are to be discussed along with mention of key uncertainties.
1984-04-01
Technical Paper
840902
Charles Jesse Kahane
A history of the evaluation of existing motor vehicle safety devices by the National Highway Traffic Safety Administration and other researchers. The discussion emphasizes observations of researchers toward the safety standards and the extent to which these have influenced or were influenced by evaluations. Issues concerning energy absorbing steering columns, head restraints, side door beams and windshield glazing and bonding are covered in detail. This paper presents the views of the author and not necessarily those of the National Highway Traffic Safety Administration (NHTSA).
Viewing 22051 to 1 of 1

Filter