Over the last few years much interest has been shown in Dimethyl Ether (DME) as a new fuel for diesel cycle engines. DME combines the advantages of a high cetane number with soot-free combustion, making it eminently suitable for compression engines. According, however, to past engine test results, the engine output of a DME engine lacking compatibility as a DME injection system, is low in comparison with a diesel engine. Required is development of a DME injection system conforming to DME properties.
The purpose of this work is to investigate the feasibility of DME application for a conventional jerk-type in-line injection system that has the actual result of use of a comparatively low lubricity fuel such as methanol. This injection system has possibilities for DME application by means of 1) increasing the effective stroke, 2) spreading the nozzle orifice area, 3) compensating the injection quantity according to fuel temperature, and 4) optimizing the flow condition of a low-pressure fuel supply system.
The test engine was a four-cylinder, 4.57 liter, turbocharged, light-duty truck s diesel engine. The original diesel injection system was replaced by an optimized jerk-type in-line DME injection system. The engine test results showed that good engine performance and low exhaust emissions with optimized injection timing. The engine output and specific fuel consumption levels were as good as the base diesel engines.