1 前言 柴油机由于燃油经济性、可靠性和耐久性优越而成为商用车上的主流发动机。特别是中重型汽车用柴油机在欧洲、美国和日本等国市场上占有稳固的地位。一方面,出于环保考虑,人们还认定柴油机在防止地球变暖方面发挥越来越重要的作用。除了要求进一步降低PM和NO_x排放和油耗外,潜在性市场的需要也要求降低柴油机运行费用,提高其可靠性和寿命,提高动力性能和可操纵性,降低噪声, 1 Introduction Diesel engines are the mainstream engines on commercial vehicles due to their superior fuel economy, reliability and durability. In particular, diesel engines for medium and heavy vehicles occupy a solid position in the markets of Europe, the United States and Japan. On the one hand, for environmental reasons, people also recognize that diesel engines play an increasingly important role in preventing global warming. In addition to requiring further reductions in PM and NO x emissions and fuel consumption, the need for a potential market also requires a reduction in diesel operating costs, increased reliability and longevity, improved power performance and maneuverability, reduced noise,