中文摘要：

为改善二甲醚发动机的燃油经济性,在一台直喷二甲醚发动机上进行台架试验,研究燃料供给系统结构参数以及往二甲醚里添加高热值的液化石油气（LPG）对二甲醚发动机经济性的影响。结果表明,适当增大喷射泵的柱塞直径、增加喷嘴喷孔数目并减小喷孔尺寸以及往二甲醚里掺混质量分数为30%的LPG燃料均能有效改善二甲醚发动机的燃油经济性。

英文摘要：

In order to improve the fuel economy of the dimethyl ether （DME） engine, bench tests were conducted on a direct injection DEM engine. The influences of parameters of DME fuel supply system and addition of high heat value liquefied petroleum gas（LPG） content in blended fuel on the fuel economy of the DME engine were investigated. The results show that the fuel economy of the DME engine has been improved with the increase of plunger diameter, the increase of orifice number and the decrease of hole diameter of injector nozzle at the same time, and the use of DME-LPG blended fuel with 30% LPG.