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某某纺织高等专科学校机械工程与自动化系
毕业设计
班级：层次：□本科□专科
学生学号：指导教师：
学生某某：学生专业：汽车检测与维修
某某纺织高等专科学校机械工程与自动化系
年月日
摘要
随着我国居民生活水平的不断提高，汽车行业也迅速开展开来。而随着科技开展，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。症状表现比拟明显，发生原因比拟复杂，主要是汽车内部有故障没有被注意，开展成突发性损坏。
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判断汽车故障，一般响声比拟沉闷并且伴有较强烈的抖振时故障比拟严重，应停车、降低发动机转速或关闭发动机来查，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。
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与排除方法。
关键词：性能，工况，异响
Abstract
China's 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 plicated 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 car's 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 fort 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 brkeof automobile brake; winter car won't start; engine flameout won't start; running sudden steering malfunction; what is more a vehicle tyre and auto spontaneous bustion. Symptoms obviously, causes more plex, mainly automotive internal fault without being noticed, develop into sudden damage.
Automobile use, failure, often the most easily to the abnormal noise of forms. Under normal circumstances, the driver and passengers can be heard. Have the experience can be based on different sound occurring position and the sounds of different frequencies and timbre judgment fault, general sound rather boring and acpanied by a strong chattering when fault is more serious, it should stop, reduce the engine speed or stop the engine to find, some sounds are certain parts of a fault occurs, the vehicle is not influenced, temporarily do not check out, the car back to the base or the nearest into the Department of vehicle maintenance and repair please experienced staff search.
This article from the automobile starting system, ignition system, fuel injection system, analyzes the fault reason and elimination method.
Keywords: performance, operating conditions, different sound
目录
目录3
第1章前言1
第2章启动系统故障与分析2
启动系统的的概述2
2.2 接通起动开关，起动机不转故障2
2.3 起动机运转无力故障3
2.4 起动机空转故障3
2.5 起动机转动时有撞击声故障4
2.6 维修案例5
第3章燃油喷射系统故障与分析7
3.1 燃油喷射系统概述7
3.2 检测诊断与维修电控汽油喷射系统须知事项7
3.3 根本的诊断方法8
3.4 电子控制燃油喷射系统的常见故障8
3.5 几种最常见故障的诊断程序9
电控系统的故障诊断与检修10
3.7 电喷车启动困难分析11
3.8 维修案例13
第4章冷却系统故障与分析21
4.1 发动机冷却系统概述21
水温过高21
4.3 冷却液泄漏22
4.4 冷却液消耗异常22
4.5 发动机过热23
4.6 发动机工作温度过低23
4.7 维修案例23
发动机冷却系案例分析23
第5章润滑系统故障与分析25
5.1 润滑系统概述25
汽车爆胎5.2 润滑系统出现报警25
5.3 发动机机油压力过高25
5.4 机油消耗过大26
5.5机油变质26
5.6 机油压力表针出现抖动28
5.7 维修案例28
第6章电控点火系统故障与分析30
6.1 电控点火系统概述30
6.2 火花塞故障30
6.3 点火系统低压电路局部故障30
6.4 点火系统高压电路局部故障31
6.5 凸轮轴位置传感器与点火系统关系31
6.6 维修案例32
第7章氧传感器在电控汽车故障检修中的应用33
7.1 氧传感器的概述33
7.2 氧传感器对维修检测的作用33
氧传感器故障波形与分析34
7.4 维修案例38
第8章电控燃油喷射发动机故障自诊断42
8.1 电喷发动机故障自诊断系统概述42
8.3 传感器的检测43
8.4 主要执行元件的检测44
8.5 ECU 电脑控制单元的检测45
8.6 维修案例45
第9章总结体会48
致谢49
声明50
参考文献51
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