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Technical Paper

Extending Injector Life in Methanol-Fueled DDC Engines Through Engine Oil and Fuel Additives

1990-10-01
902227
Considerable development effort has shown that conventional diesel engine lubricating oil specifications do not define the needs for acceptable injector life in methanol-fueled, two-stroke cycle diesel engines. A cooperative program was undertaken to formulate an engine oil-fuel additive system which was aimed at improving performance with methanol fueling. The performance feature of greatest concern was injector tip plugging. A Taguchi matrix using a 100 hour engine test was designed around an engine oil formulation which had performed well in a 500 hour engine test using a simulated urban bus cycle. Parameters investigated included: detergent level and type, dispersant choice, and zinc dithiophosphate level. In addition, the influence of a supplemental fuel additive was assessed. Analysis of the Taguchi Matrix data shows the fuel additive to have the most dramatic beneficial influence on maintaining injector performance.
Technical Paper

Review of the Cold Starting Performance of Methanol and High Methanol Blends in Spark Ignition Engines: High Methanol Blends

1990-10-01
902181
This paper summarizes the results of a survey and analysis of cold starting data for spark ignition engines utilizing high methanol blends. All available published information, as well as additional data supplied by contributing agencies was considered. The report includes graphical comparisons of test results and a detailed discussion of the various factors which influence cold starting. Recommendations are made for further work needed to improve cold starting.
Technical Paper

Influence of Engine Buildup Variables on the ASTM Sequence VI Fuel Efficient Oil Test

1990-10-01
902164
Using a seven-step quality improvement process, some of the engine build-up factors adversely influencing the severity and precision of the Sequence VI dynamometer test were examined. Insights from engineering (theory) and database (statistical) analyses enabled a 23 factorial experiment to identify oil ring tension, piston ring side clearance, and piston fit as critical parameters in a 3-oil, 9-engine, 28-test program. High ring tension was shown to emphasize the friction reducing capability of higher performing oils and the deficiency of a lower performing oil. Interactions were noted. A helpful correlation of test severity with the engine calibration indicators was shown.
Technical Paper

Transit Bus Operation with a DDC 6V-92TAC Engine Operating on Ignition-Improved Methanol

1990-10-01
902161
The use of methanol as a fuel in transit buses is being demonstrated through the use of diesel engine retrofits and an ignition improver to methanol. This project is aimed at retrofitting the Detroit Diesel Corporation (DDC) 6V-92TAC diesel engine in a GM RTSII bus to operate on methanol. The engine is modified by installing higher compression ratio pistons, higher flowrate mechanical fuel injectors, and a different blower. The bus fuel system is also modified to accommodate the properties of methanol. New fuel lines are installed, and the diesel fuel tank is replaced with two stainless steel tanks. A high-pressure electric fuel pump and a fuel cooler are used to prevent methanol from boiling in the engine. Currently, three buses have been retrofitted. The buses operate at the Southern California Rapid Transit District (SCRTD) in Los Angeles, California.
Technical Paper

Dimethyl Ether as a Methanol Ignition Improver: Substitution Requirements and Exhaust Emissions Impact

1990-10-01
902155
Methanol is one of the leading alternatives to diesel fuel and gasoline. In Diesel applications methanol's low cetane number has necessitated the use of glowplugs, spark plugs or expensive additives for ignition assistance. This paper reports on the use of Dimethyl Ether (DME) as an ignition improver for neat methanol in a compression ignition engine. Gaseous DME was admitted to the intake air stream of a four stroke test engine operating on directly injected methanol. The amount of DME required to achieve stable operation over the load/speed range of the engine without the use of a glow plug was determined. DME's effect on ignition delay and rate of pressure rise is discussed. Exhaust emissions were measured and compared with operation on methanol with glow plug assisted ignition. Hydrocarbon emissions were reduced by a factor of 10 at light loads. Aldehyde emissions were also reduced.
Technical Paper

Laboratory Evaluation of Safety-Related Additives for Neat Methanol Fuel

1990-10-01
902156
An extensive literature search was conducted and potential additive candidates were identified to improve the safety aspects associated with the use of methanol as a motor fuel. Before any laboratory measurements were conducted, candidate additives were evaluated for possible formation of known or suspected toxic compounds as combustion products. The remaining potential additives were then screened for their effectiveness in improving methanol fuel properties in a laboratory test program emphasizing flame luminosity, lubricity, and flammability. Flame luminosity was measured with a specially designed system to monitor the light produced by the flame in lux. Lubricity was measured with a Ball-on-Cylinder Lubricity Evaluator (BOCLE). For flammability limits, a device was designed to determine the presence of flammable vapors above the liquid at different additive concentrations.
Technical Paper

Evaluation of Possible Methanol Fuel Additives for Reducing Engine Wear and/or Corrosion

1990-10-01
902153
The use of fuel additives is one possible approach to reduce wear and corrosion in methanol fueled automobile engines. One hundred and six compounds added to M100 fuel in modest concentrations (1%) were tested in a Ball on Cylinder Machine (BOCM) for their ability to improve lubricity. The most promising candidates were then tested in an engine using a modified ASTM Sequence V-D wear screening test. Additive performance was measured by comparing the buildup of wear metals in the oil to that obtained from an engine fueled with neat M100. The BOCM method of evaluating the additive candidates proved inadequate in predicting abrasive engine wear under the test conditions utilized for this research program.
Technical Paper

Methanol-Fueled Caterpillar 3406 Engine Experience in On-Highway Trucks

1990-10-01
902160
A variety of “alternative” fuels are being considered as potential future replacements for petroleum-based fuels. One of the leading contenders for replacing diesel fuel in some heavy duty applications is methanol, since methanol can be made from abundantly- available materials such as natural gas, coal, and biomass, and because neat methanol can result in reduced NOx and particulate exhaust emissions relative to diesel fuel. Because of various fuel property differences between methanol and diesel fuel, engine modifications must be made to the conventional diesel engine to allow it to utilize methanol fuel. A patented (1) ignition-assist combustion system initially applied to a 2 valve, 4 stroke Caterpillar 3306 DIT engine (121 mm bore) demonstrated methanol combustion feasibility in a tractor application (2).
Technical Paper

Ford Methanol FFV Performance/Emissions Experience

1990-10-01
902157
The progress and interim results of the New York State Energy Research and Development Authority's Flexible Fuel Vehicle (FFV) demonstration program are reported. Four FFVs have been operated for a total of more than 150,000 miles. Two FFVs were operated for 50,000 miles on gasoline and have switched over to using M85. The other two vehicles have been primarily using MB5. The FFVs were tested for exhaust emissions on a chassis dynamometer over the FTP, HFET and NYCC driving schedules. The vehicles were fueled with gasoline, M85 and in one test M60. In a series of tests they were also evaluated using inactive catalysts to measure catalyst effectiveness and deterioration. Results for the dependency of emissions on fuel composition, mileage and driving schedule are presented. In general, emissions decreased with increasing methanol content and increased with mileage.
Technical Paper

Technology Demonstration of U.S. Army Methanol-Fueled Administrative Vehicles

1990-10-01
902158
A technology demonstration program using modified administrative-type vehicles was conducted by the Army to determine the feasibility of using methanol as an alternative fuel. Over 1,026,000 miles (1,651,190 km) were accumulated using 64 sedan and pickup vehicles. Approximately 750,000 of these miles (1,207,010 km) were accumulated using M85 methanol fuel. Using M85 increases the fuel cost by a factor of approximately 3.0. No catastrophic engine failure occurred with the use of the M85 fuel. Even though wear rates, indicated from used oil samples analyses, obtained when using M85 fuel appear to be 2 to 4 times those obtained using unleaded gasoline, actual wear, from inspections and measurements, does not appear to be as severe. M85 refueling stations were set up at four fleet test sites, and no significant operational or safety problem was encountered during the program.
Technical Paper

Volvo's MEP and PCP Engines: Combining Environmental Benefit with High Performance

1991-01-01
910010
In two research programs, Volvo has investigated high performance turbocharged versions based on the new 3-litre inline six-cylinder naturally aspirated engine. Power and torque targets were 180 kW and 385 Nm respectively, with a wide usable torque range. The MEP-(Methanol Environment Performance)-project was linked to alternative fuel studies and focused on methanol (M85) and Flexible Fuel Vehicle-(FFV)-development. With alternative fuels, it is important to investigate not only the emissions and fuel efficiency, but also the performance potential, in particular when used in turbocharged engines. The MEP-engine could be reduced to 2.5 litre displacement, due to the good specific performance with M85 fuel. Higher charge pressures could be used compared to gasoline. An M85 turbocharged high performance engine must be designed for higher peak combustion pressures.
Technical Paper

Applications of High Performance P/M Aluminum in Internal Combustion Engines

1991-02-01
910156
Powder Metallurgy (P/M) renders the possibilities to tailor material properties using rapid solidification or mechanical alloying processes totally different to the options of ingot metallurgy (I/M). For demanding applications in internal combustion engines new materials have become more important because of environmental and/or performance reasons. Weight reductions to improve the performance or reduce the consumptions and consequently the amount of exhaust gases and increase of temperatures at different locations of an engine need better aluminum materials. P/M solutions are described from the point of view of material's processing and general properties. The potential for automotive pistons is discussed with several examples.
Technical Paper

Stratification of Swirl Intensity in the Axial Direction for Control of Turbulence Generation During the Compression Stroke

1991-02-01
910261
Control of turbulence during the compression stroke is suggested by both theoretical calculations and experimental results obtained with an LDV measurement in a motored engine. The authors have found experimentally that when an axial distribution of swirl intensity exists, a large-scale annular vortex is formed inside the cylinder during the compression stroke and this vortex generates and transports turbulence energy. A numerical calculation is adopted to elucidate this phenomenon. Then, an axial stratification of swirl intensity is found to generate a large-scale annular vortex during the compression stroke by an interaction between the piston motion and the axial pressure gradient. The initial swirl profile is parametrically varied to assess its effect on the turbulence parameters. Among calculated results, turbulence energy is enhanced strongest when the swirl intensity is highest at the piston top surface and lowest at the bottom surface of the cylinder head.
Technical Paper

Development of Brushless Fuel Pump

1991-02-01
910393
To achieve a clean atmospheric environment and a stable fuel supply, considerations are being given to the use of methanol fuel as one of the fuel used by alternative fuel vehicles. This report describes the development and studies of a brushless motor-driven fuel pump to be employed for a methanol electronic fuel injection system. Several problems remained to be solved for the fuel pumps used with methanol fuel, and hence considerations were given to the following items: (1) A control unit was developed that can be used in high-pressure fuel. This unit has been downsized substantially due to the adoption of a system in which it is subjected to forced cooling with the fuel.
Technical Paper

The Effects of Ceramic Coatings on Diesel Engine Performance and Exhaust Emissions

1991-02-01
910460
An experimental investigation of the effects of ceramic coatings on diesel engine performance and exhaust emissions was conducted. Tests were carried out over a range of engine speeds at full load for a standard metal piston and two pistons insulated with 0.5 mm and 1.0 mm thick ceramic coatings. The thinner (0.5 mm) ceramic coating resulted in improved performance over the baseline engine, with the gains being especially pronounced with decreasing engine speed. At 1000 rpm, the 0.5 mm ceramic coated piston produced 10% higher thermal efficiency than the metal piston. In contrast, the relatively thicker coating (1 mm), resulted in as much as 6% lower thermal efficiency compared to baseline. On the other hand, the insulated engines consistently presented an attractive picture in terms of their emissions characteristics. Due to the more complete combustion in the insulated configurations, exhaust CO levels were between 30% and 60% lower than baseline levels.
Technical Paper

A Study of Decrease Oil Consumption for NSOR-Two-Ring Package Piston

1991-02-01
910435
Furuhama(1)* proposed the new two ring package consist of a pressure ring and a narrow single-rail oil ring (NSOR) in 1985. Number of studies(2) have been done for the purpose of reducing the oil consumption (OC) in this ring package. However, OC reduction problem has been still remaining to solve as only one serious problem of this ring package. The reasons of a larger OC in the new ring package than the conventional three ring has been hardly understood, considering the OC control ability on second ring in three ring package will not so large since the fact that the oil film thickness is thicker than that of the oil ring. In this study, the mechanism of OC increase in new ring package was found out at last, as a result, OC of new ring package piston was improved up to the same level of conventional three ring package piston.
Technical Paper

Development of Light Weight High Strength Aluminum Alloy Piston with Cooling Gallery Manufactured Using Squeeze Casting Technique

1991-02-01
910434
In recent years, demands for increased output and low fuel consumption in automobile engines have been mounting. Light weight and high performance is demanded of the main operating parts, such as pistons. In response to these demands, the crown thickness and pin boss unit thickness has been reduced by tremendous improvements in the fatigue strength, compared to strength obtained by conventional methods, by utilizing Squeeze Casting techniques. In addition, the thickness of the inside face of the pistons has been reduced by making use of a split core. Furthermore, by manufacturing a cooling gallery, the heat load has been reduced; by introduction of hollow regions, an extremely light weight and compact piston has been developed. Three new techniques are indicated here. Firstly, the technique of attaining soundness in material and excellent fatigue strength by the Squeeze Casting technique, which is superior to those attained by conventional methods.
Technical Paper

Advances in High Temperature Components for the Adiabatic Engine

1991-02-01
910457
An advanced low heat rejection engine concept has been selected based on a trade-off between thermal insulating performance and available technology. The engine concept heat rejection performance is limited by available ring-liner tribology and requires cylinder liner cooling to control the piston top ring reversal temperature. This engine concept is composed of a titanium piston, headface plate and cylinder liner insert with thermal barrier coatings. Monolithic zirconia valve seat inserts, and thermal barrier coated valves and intake-exhaust ports complete the insulation package. The tribological system is composed of chrome oxide coated cylinder, M2 steel top piston ring, M2 steel valve guides, and an advanced polyol ester class lubricant.
Technical Paper

Development of an Optical Fuel Composition Sensor

1991-02-01
910498
Two types of the Fuel Composition Sensor (FCS) are under development for the following purposes; (1) Detection of methanol concentration in methanol blended gasoline fuel for FFV. (2) Detection of gasoline quality, heavy or light, for vehicles using ordinary gasoline at the fuel. Measurement of refractive index or dielectric constant is effective for the purpose of above (1), and measurement of refractive index is effective for the purpose of above (2). Of the sensors of these two types, the FCS of new optical type which has been developed earlier is descrived in this report. The FCS is designed compact, has a high response, and gives liner voltage output within any desired range of refractive index. As the primary advantages, the FCS is resistive to deposits on optical parts and is highly durable as a result of applying refractive method and photo-position detection system.
Technical Paper

The 1990 SAE Methanol Challenge: Summary of a Successful Student Design Competition

1991-02-01
910570
A follow-up to the 1989 Society of Automotive Engineers (SAE) Methanol Marathon called the Methanol Challenge was held in April 1990. One of a series of engineering student competitions using alternative fuels organized and conducted by the Center for Transportation Research at Argonne National Laboratory, the Methanol Challenge pushed the technology for dedicated M85 (85% methanol, 15% hydrocarbon fuel) methanol passenger cars to new levels. The event included complete federal exhaust emissions, cold-start and driveability, performance, and fuel economy testing. Twelve teams of student engineers from the United States and Canada competed in the Challenge using Chevrolet Corsicas donated by General Motors (GM) to the schools. The winning car, from the University of Tennessee, simultaneously demonstrated extremely low emissions, dramatically increased performance, and significantly improved fuel economy.
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