发动机冷却系统的检修与故障分析

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摘要

目前，随着我国汽车保养行业的快速发展，汽车维修也发展迅速，因此对发动机冷却系统的检修与故障分析尤为重要。

本文就从冷却系统入手论述了发动机冷却系统的作用、类型与组成、工作原理、维护与保养，并结合具体的案例，通过对发动机冷却系统的故障现象做出相应的分析，利用技术手段,最终使故障得到排除。使发动机始终处于最佳工作温度，从而发挥发动机的最佳功效。

懂得发动机冷却系统的结构、工作原理和检测方法，使得驾驶员及时了解发动机的工作状态，并能及时掌握并维修冷却系统的故障，使发动机始终处于最佳工作状态。可以减少发动机因冷却系统问题出现的故障。 关键词：冷却系统；节温器；故障检测

Abstract

Now, with the industry's rapid development of China's vehicle maintenance, vehicle maintenance is also developing rapidly, so the engine cooling system maintenance and fault analysis is particularly important.

This article discusses the role of the engine cooling system, cooling system from the start, type and composition, working principle, care and maintenance, combined with specific cases, the phenomenon of the failure of the engine cooling system and make appropriate use of technical means, the final so that the fault has been eliminated. So that the engine is always in the optimum operating temperature, to play the best efficiency of the engine.

Understand the structure of the engine cooling system works and testing methods, allowing the driver to keep abreast of the state of the engine, and can grasp and maintenance of cooling system failure, the engine is always in top working condition. You can reduce engine failures due to cooling system problems. Key words: cooling systems; thermostat; fault detection

目 录

摘要 ........................................................................................................................... 1 1 冷却系统的概述 ................................................................................................... 6 1.1冷却系统的作用 ................................................................................................ 6 1.2冷却系统的分类 ................................................................................................ 6 1.3冷却系统的组成及其工作原理 ........................................................................ 6 1.3.1小循环 ............................................................................................................ 7 1.3.2大循环 ............................................................................................................ 8 1.3.3大小循环同时运行 ........................................................................................ 8 2冷却系统的主要部件、结构及其特点 ............................................................... 9 2.1冷却系统的主要部件 ........................................................................................ 9 2.1.1散热器 ............................................................................................................ 9 2.1.2冷却风扇 ........................................................................................................ 9 2.1.3冷却水泵 ...................................................................................................... 10 2.1.4节温器 .......................................................................................................... 10 2.1.5冷却液温度传感器 ...................................................................................... 11 2.2 冷却液介质 ..................................................................................................... 12 2.2.1 冷却介质的功能 ......................................................................................... 12 2.2.2冷却介质的类型 .......................................................................................... 13 3冷却系统的维护与保养 ...................................................................................... 14 3.1冷却系统的维护 .............................................................................................. 14 3.1.1检查冷却液 .................................................................................................. 14 3.1.2冷却液使用注意事项 .................................................................................. 14 3.1.3清洗冷却系 .................................................................................................. 14 3.2气缸水套 .......................................................................................................... 15 3.3冷却水泵和节温器 .......................................................................................... 15

3.4散热水箱和冷却风扇 ...................................................................................... 16 3.5夏季保养 .......................................................................................................... 16 3.5.1确保冷却系统效能良好 .............................................................................. 16 3.5.2时刻关注冷却液温度 .................................................................................. 17 3.6冬季的保养 ...................................................................................................... 17 3.6.1保养发动机冷却系统 .................................................................................. 17 4冷却系统的常见故障及排除方法 ...................................................................... 18 4.1冷却系统水温高的原因分析 .......................................................................... 18 4.1.1冷却液不足 .................................................................................................. 18 4.1.2散热器的散热能力差 .................................................................................. 18 4.1.3风扇工作不良 .............................................................................................. 19 4.1.4气缸垫的烧蚀 .............................................................................................. 19 4.1.5水泵的工作不良 .......................................................................................... 19 4.1.6节温器的主阀门开度过小 .......................................................................... 20 4.1.7点火正时的过早或过迟 .............................................................................. 20 4.1.8其他可能导致发动机冷却液温度过高的原因 ......................................... 21 4.2冷却液流失 ...................................................................................................... 21 4.2.1冷却液的外渗 .............................................................................................. 21 4.2.2冷却液的内渗 .............................................................................................. 22 4.3节温器损坏 ...................................................................................................... 23 4.4冷却系统的“困气” ...................................................................................... 23 4.5 发动机过冷故障现象 ..................................................................................... 24 5电子控制发动机冷却系统 .................................................................................. 25 5.1系统组成示意图 .............................................................................................. 25 5.2冷却系统布局图与冷却液分配单元图 ......................................................... 25 5.3温度调节单元 .................................................................................................. 26

5.4温度调节单元在各工况时的状态.................................................................. 27 5.4.1发动机冷起动、小负荷时 .......................................................................... 27 5.4.2发动机全负荷时 .......................................................................................... 27 5.5带电子控制冷却系统的发动机控制单元与系统工作原理 ......................... 28 5.5.1带电子控制冷却系统的发动机控制单元 ................................................. 28 5.5.2输入与输出信号 .......................................................................................... 28 5.5.3基本工作原理 .............................................................................................. 28 5.5.4开暖风时的控制 .......................................................................................... 29 5.5.5两个冷却液温度传感器（G62和G83）及散热风扇控制 ....................... 29 6结论 ...................................................................................................................... 31 致 谢 ....................................................................................................................... 32 参考文献 ................................................................................................................. 33