Effect of Multiple Injection Strategies on the Emission Characteristics of Dimethyl Ether (DME)-Fueled Compression Ignition Engine

Abstract

An experimental investigation was conducted to evaluate the effect of multiple injection strategies on the performance of DME-fueled engine and the reduction of exhaust emissions. In this work, three types of multiple injection strategiesincluding split injection, pilot injection, and partial premixed charge compression ignition (PPCCI)are introduced, and the results are compared with those obtained by single injection under optimal operating conditions. To analyze the injection characteristics of dimethyl ether (DME) fuel, the injection rate profiles for multiple injections were investigated, in terms of their energizing current and injection rate. The result of an engine test reveals that multiple injection strategies of split and pilot injection showed a reduction in NOx emissions of ∼75% with a minor reduction in the indicated mean effective pressure (IMEP). PPCCI combustion offered a reduction in NOx emissions of ∼97.1%, whereas the IMEP was reduced by 23%. Under all operating conditions, no measureable soot emission was observed in the DME engine.