1.前言今日的轿车用汽油机在经过了多项技术改进后,已经极大地提高了输出功率,实现了用户所期望的行驶性能。近年来为了适应越来越受重视的环保要求,并努力减轻地球温室化效应及大气污染,提高燃油经济性技术和降低排放技术的开发成为当务之急。在各项改良技术中,可变气门机构技术作为少 1. Introduction Today’s sedan gasoline engine has undergone a number of technical improvements and has greatly increased the output power to achieve the desired driving performance. In recent years, in order to meet the more and more attention to environmental protection requirements and efforts to mitigate the global warming effect and air pollution, improve fuel economy and reduce emissions technology development has become a top priority. In various improvements, variable valve train technology as less