一 引言 汽车在当今交通运输中的重要地位,决定了汽车节能在国民经济发展中的特殊意义。多年来,人们为改善汽车的操作和经济性能,对汽车总体与部件设计进行了大量的改造与更新。然而,现用的汽车,特别是城市内行驶的客车与货车,耗油性能还不能显著改善,其原因有如下几点: I. INTRODUCTION The importance of automobiles in today’s transportation determines the special significance of automobile energy conservation in the development of the national economy. Over the years, people have done a lot of revamping and updating of the car’s overall and component design to improve the operation and economic performance of the car. However, the current consumption of vehicles, especially in the city of passenger cars and trucks, fuel consumption performance can not be significantly improved for the following reasons: