Experimental study on exhaust emissions from a multi-cylinder DME engine operating with EGR and oxidation catalyst

The recent increase in the world oil price and concern with the growing awareness of the environmental problems associated with the use of petroleum fuels, has led to more interests on alternative fuels. DME is found to be one kind of promising clean alternative fuel for diesel engine. Smokeless emission can be realized under all operating conditions. This characteristic provides a potential for a large EGR ratio on the DME engine. Experimental results indicate that NOx emission can be reduced about 40% at a large EGR ratio without visible smoke and deterioration in thermal efficiency of DME engine. However, CO emission increases with the rise of EGR ratio. A commercial oxidation catalytic converter is used to investigate its influence on CO emission. Very promising results with respect to CO emission reduction can be achieved in DME engine. It is obvious that vehicle DME engine can meet more strict emission regulation with an integrated system with EGR and oxidation catalytic after treatment.