中文摘要：

通过理论分析的方法对汽车排气尾流中的微粒演变特性进行了研究．建立了描述汽车排气尾流中微粒演变过程的核化模型和凝并模型．在此基础上，对排气微粒在尾流中的核化与凝并过程以及影响因素进行了分析．研究结果表明：核化增加了尾流中超细微粒的数量；燃料硫含量、排气稀释比、尾流温度以及相对湿度等对微粒的核化有较大的影响；凝并将显著改变尾流中的微粒粒径分布；排气微粒的初始数密度和粒径分布对尾流中的微粒凝并具有较大的影响．

英文摘要：

The evolution characteristics of exhaust particles in vehicular plume have been studied by the method of theory analysis. The models of nucleation and coagulation of exhaust particles were built up, and based on these models the evolution characteristics of exhaust particles in the process of nucleation and coagulation in exhaust plume have been investigated parametrically. The simulated results showed that a large number of new nano-particles were created in the nucleation process, which was influenced strong- ly by the fuel sulfuric content, exhaust dilution ratio, temperature and relative humidity; particle size distribution in the plume was changed in the coagulation process; and the coagulation of particles was strongly dependent on the initial particle concentration and particle size distribution.