（毕业设计论文）《汽车发动机部分故障与分析》.doc

PAGE 摘要 　　 　　随着我国居民生活水平的不断提高,汽车行业也迅速发展开来。而随着科技发展,大众不断追求高性能、高质量汽车,汽车生产、制造也应时代潮流不断运用各种新材料、新技术、新工艺,现代汽车的技术性能越来越好。由此,汽车结构越来越复杂,检测维修、故障诊断难度也相应增大。汽车故障常种类繁多比如汽车性能异常、汽车使用工况异常、汽车异常响声。 　　汽车性能异常就是汽车的动力性和经济性差，主要表现在汽车最高行驶速度明显低，汽车加速性能差；汽车燃油消耗量大和机油消耗量大。汽车乘坐舒适性差，汽车振动和噪声明显加大。汽车操纵稳定性差，汽车易跑偏，车头摆振；制动跑偏，制动距离长或无制动等。 　　汽车使用中突然出现某些不正常现象，应加以预防：行驶中发动机突然熄火；需要制动时汽车无制动；冬季汽车发动不起来；发动机熄火后发动不起来；行驶中转向突然失灵；更有甚者汽车爆胎和汽车自燃起火等。症状表现比较明显，发生原因比较复杂，主要是汽车内部有故障没有被注意，发展成突发性损坏。 汽车使用中，发生故障，往往最易以异常响声的形式表现出来。正常情况下驾驶员和乘坐者都可以听到。有经验者可以根据异响发生的部位和声音的不同频率和音色判断汽车故障，一般响声比较沉闷并且伴有较强烈的抖振时故障比较严重，应停车、降低发动机转速或关闭发动机来查找，有些声音是某些部位发生了故障，不影响汽车使用，一时查不出来，可将汽车驶回基地或就近驶入汽车维修部门请有经验的人员查找。 本文从汽车启动系统、点火系统、燃油喷射系统等分析起故障原因及排除方法。 关键词：性能，工况，异响 Abstract Chinas standard of living continues to improve, the automotive industry is developing rapidly. But with the development of science and technology, the constant pursuit of high performance, high quality car, automobile production, manufacturing should be the trend of the times the continuous use of a variety of new materials, new technology, new technology, the technology of modern automobile performance is getting better and better. Thus, the car more and more complicated structures, detection and repair, will also increase the difficulty of fault diagnosis. Automobile fault often variety such as car performance anomaly, automobile, automobile abnormal conditions of abnormal noise. Automobile performance anomaly is the cars power and economy performance is poor, mainly in the automobile the maximum speed was low, vehicle acceleration performance is poor; automobile fuel consumption and oil consumption. Vehicle ride comfort is poor, the automobile vibration and noise increase significantly. Vehicle handling stability is poor, auto deviation, the front pendulum; braking deviation, long braking distance and braking. The car used in the sudden appearance of some abnormal phenomena, should be amenable to prevention: running the engine cut out;when in need of brke of automobile brake; winter car wont s