This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Dimethyl Ether as an Ignition Enhancer for Methanol-Fueled Diesel Engines
Annotation ability available
Sector:
Language:
English
Abstract
Methanol-fueled diesels may be an attractive means of meeting future, more restrictive diesel particulate standards since methanol combustion forms very little soot. Unfortunately, methanol's autoignition temperature is high, and some means of improving its ignition is required. Therefore, we have investigated the use of dimethyl ether (DME), aspirated with the combustion air, to enhance the ignition of the injected methanol. A small, on-board catalytic reactor could be used to generate DME from the methanol fuel. This system requires minimal modifications to the engine design, and does not require use of an additive or fuel other than methanol.
In this study, we measured maximum cylinder pressure and rate of pressure rise, ignition delay, emissions, and relative efficiencies for a single-cylinder, direct injection, high-speed diesel engine operated on both diesel fuel and methanol-DME. The tests showed DME to be an effective ignition-enhancer over the engine's entire operating range, without excessive maximum cycle pressures, with lower maximum rates of pressure rise, and with efficiencies equivalent to those achieved on diesel fuel. Additionally, ignition timing was controllable (within limits) by adjusting the concentration of DME in the inlet air. At a given operating point, acceptable operation was achieved with a wide range of DME concentrations.
Particulate emissions were greatly reduced during operation on methanol-DME. NOx emissions were also reduced when compared to diesel-fuel operation, but were more a function of ignition timing than fuel. Moderate increases were seen in unburned hydrocarbons. As with diesel-fueled operation, CO emissions were negligible, but were slightly higher during operation on methanol-DME. However, in the air-rich exhaust of a diesel engine, HC and CO are considerably easier to control with catalytic converters than particulates and NOx.
Recommended Content
Authors
Topic
Citation
Karpuk, M., Wright, J., Dippo, J., and Jantzen, D., "Dimethyl Ether as an Ignition Enhancer for Methanol-Fueled Diesel Engines," SAE Technical Paper 912420, 1991, https://doi.org/10.4271/912420.Also In
References
- Cartelleri, W.P. Wachter W.F. 1987 Status Report on a Preliminary Survey of Strategies to Meet US-1991 HD Diesel Emission Standards Without Exhaust Gas Aftertreatment SAE Paper # 870342 Warrendale, PA Society of Automotive Engineers
- Engine Manufacturers Association (EMA) 1988 The Potential of Methanol as an Alternative Fuel for Heavy Duty Engines SAE B-532 Warrendale, PA Society of Automotive Engineers
- Karpuk, M.E. Cowley S.W. 1988 On Board Dimethyl Ether Generation to Assist Methanol Engine Cold Starting International Fuels and Lubricants Meeting and Exposition Portland, Oregon Oct. 10-13 SAE Paper # 881678 Warrendale, PA Society of Automotive Engineers
- Brook, D.L. Rallis C.J. Lane N.W. Cipolat D. 1984 “Methanol with Dimethyl Ether Ignition Promoter as Fuel for Compression Ignition Engines,” Proc. 19 th IECEC San Francisco August 19-24
- Galvin, M.P. 1988 “Aspirated Ether Ignition Systems for Methanol Fuelled Diesel Engines,” VIII Int. Symp. on Alcohol Fuels Tokyo, Japan
- Green, C.J. Cockshutt N.A. King L. 1990 Dimethyl Ether as a Methanol Ignition Improver: Substitution Requirements and Exhaust Emissions Impact SAE Paper # 902155 Warrendale, PA Society of Automotive Engineers
- Siebers, D.L. Edwards C.F. 1987 Autoignition of Methanol and Ethanol Sprays under Diesel Engine Conditions SAE Paper #807588 Warrendale, PA SAE
- Bechtold, R.L. 1988 Status of Alcohol Fuels Utilization Technology for Highway Transportation: A 1986 Perspective II Compression Ignition Engines , ORNL/Sub/85-22007/3 Springfield, VA NTIS
- Allsup, J.R. 1983 Emissions, Efficiency, and Durability of Agricultural Diesel Engines Using Low-Proof Ethanol SAE Paper # 831353 Warrendale, PA Society of Automotive Engineers
- Jiang, Q. Ottikkutti P. VanGerpen J. VanMeter D. 1990 The Effect of Alcohol Fumigation on Diesel Flame Temperature and Emissions SAE Paper # 900386 Warrendale, PA SAE