改革开放以来，随着经济的发展和人民生活水平的提高，我国的汽车保有量在不断增加。由于排放法规不完善和发动机技术的发展滞后，汽车尾气排放已经成为许多大中城市的主要污染源。为了治理汽车尾气对大气环境的污染，世界许多国家实行了越来越严格的排放法规，而严格的排放法? Since the reform and opening up, with the development of economy and improvement of people’s living standard, the car ownership in our country is constantly increasing. Due to imperfect emission laws and the slow development of engine technology, automobile exhaust emissions have become the major sources of pollution in many large and medium-sized cities. In order to control the pollution of automobile exhaust to the atmospheric environment, many countries in the world have implemented more stringent emission regulations and the strict emission law?