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开展了4缸直喷柴油机燃用二甲醚时的燃烧和排放特性的研究。结果表明,适当增加喷油器伸出缸盖底平面的距离,采用流通截面较大的喷油器,降低启喷压力,可以提高CA498发动机燃用二甲醚时的热效率。燃用二甲醚时,发动机缸内的最大爆发压力和压力升高率低于燃用柴油时的情况。二甲醚发动机在所有工况下均可实现无碳烟排放,NOx排放约为柴油机的50%,CO和HC排放与柴油机相当。试验结果表明二甲醚是一种高效、低排放、燃烧噪声低的柴油机新型代用燃料。
The combustion and emission characteristics of 4-cylinder direct-injection diesel engine with DME were studied. The results show that when the fuel injector extends the distance from the bottom of cylinder head, the fuel injector with larger flow cross section is adopted to reduce the pressure of start - up spray, which can increase the thermal efficiency of CA498 engine when DME is consumed. When DME is used, the maximum burst pressure and pressure rise rate in the engine cylinder is lower than when diesel fuel is used. Dimethyl ether engine can achieve soot emission under all working conditions, NOx emission is about 50% of diesel engine, CO and HC emissions are comparable with diesel engine. The experimental results show that DME is a new generation of diesel fuel with high efficiency, low emission and low noise.