Investigation of the performances of diesel engine fueled with dimethyl ether and vehicle driving tests

Experiments were carried out to investigate performance of a multi-cylinder direct-injection diesel engine with dimethyl ether (DME) as fuel. The results show that maximum torque of DME engine can exceed that of diesel engine by increasing fuel supply amount per cycle. Increasing the flowing area of nozzle orifices or the vertical distance of the nozzle tip into the cylinder and reducing opening pressure of nozzle can improve the thermal efficiency of DME engine. NO_x emission of DME engine is about 50% of that of diesel engine. Smokeless emission can be realized in all operating conditions. HC and CO emissions are close to those of diesel engine. DME engine modified with the above optimum data was mounted onto the vehicle and tested on the road. The maximum speed (120 km/h) and the accelerating performance of this vehicle could reach or exceed those of the corresponding diesel vehicle. Experiments confirm that DME is a kind of ideal alternative fuel for diesel engines.