中文摘要：

在一台增压二甲醚发动机上,研究了供油提前角和排气再循环（EGR）率的变化对发动机排放影响。结果表明,随着供油提前角的减小,发动机的NOx排放依次降低。随着EGR率的增加,发动机的NOx的排放大幅度下降,高负荷时下降幅度更大。比较了最佳EGR率和推迟喷油对二甲醚发动机排放的影响,EGR和推迟喷油均可以降低二甲醚发动机NOx排放,EGR的效果更为显著。EGR和推迟喷油都会引起HC和CO排放升高,EGR引起HC和CO的升高大于推迟喷油的影响。在降低二甲醚发动机排放方面,EGR技术比推迟喷油更具优势。

英文摘要：

Experimental investigation of fuel supply advance angle and EGR rate on emissions of a DME engine had been carried out. The results indicated that NOxemission of DME engine would be reduced with the reducing of DME fuel supply advance angle. NOxemission was reduced greatly with the increasing of EGR rate,especially at high load. The impacts of fuel supply advance angle and EGR on emissions of DME engine had been compared,both EGR rate and prolonged fuel injection would reduce NOxemission; EGR had greater impacts than that of prolonged fuel injection. Both EGR rate and prolonged fuel injection would increase HC and CO emission,while EGR had greater impact than that of prolonged fuel injection had. In all,EGR technologies showed better advantage than that of injection timing in reducing NOxemission of DME engine.