一、引言目前,柴油机已成为热力机械中使用最广泛、最经济的一种机型。由于柴油机具有比油耗低、废气中有害物排放量少等优点,在七十年代能源危机和废气排放法规日益严格的情况下,愈加得到广泛的应用。目前,柴油机的研究重点是如何进一步降低其噪声、氮氧化物排放量与比油耗。不同用途的柴油机有不同的要求,固定动力和载货汽车用的柴油机,要求有尽可能低的燃油消耗,而轿车用柴油机,则首先要求有较低的噪声和有害物排放。柴油机燃 I. Introduction At present, diesel engines have become the most widely used and the most economical type of thermal machinery. Because diesel engines have the advantages of low fuel consumption and less harmful emissions in exhaust gas, they have been widely used in the increasingly stringent energy crisis and exhaust emission regulations in the 1970s. At present, diesel engine research focuses on how to further reduce its noise, nitrogen oxide emissions and fuel consumption. Diesel engines of different uses have different requirements. Diesel engines with fixed power and truckloads require the lowest possible fuel consumption. In the case of diesel engines for passenger cars, low noise and harmful emissions are first of all required. Diesel fuel