Study on combustion and emission characteristics of a vehicle engine fuelled with dimethyl ether

This paper reports on basic investigations into identifying the optimum parameters of a fuel system for a four-cylinder, direct-injection diesel engine with dimethyl ether (DME) as fuel-such as nozzle opening pressure, nozzle type, etc. Combustion and emission characteristics of the DME engine are studied experimentally. Smokeless emission can be realized under all operating conditions; in addition, NOx, HC, CO and particulate matter (PM) emissions of the CA498 DME engine can meet Euro 3 regulations by using an oxidation catalytic converter. It is also indicated that NO, emissions can reduce by about 40 per cent at larger exhaust gas recirculation ratios with less penalty on the brake thermal efficiency of the DME engine. A DME-powered vehicle has been developed and is operating successfully on the highway. The maximum speed and accelerating performance are equivalent to those of diesel operation; the noise of the vehicle is lower than that of diesel vehicles. Very promising results with respect to emission, efficiency, durability, and combustion noise can be achieved in a DME engine.