发动机冷凝水对EGR阀腐蚀卡滞机制分析  

Mechanism Analysis on Corrosion and Stuck of EGR Valve by Condensed Water in Engine

作　　者：周婷婷 蔺桂成 管奇贤 夏英子 夏志鹏 ZHOU Tingting;LIN Guicheng;GUAN Qixian;XIA Yingzi;XIA Zhipeng(Ningbo Geely Loyal Engine Components Co.,Ltd.,Ningbo,Zhejiang 315327,China)

机构地区：[1]宁波吉利罗佑发动机零部件有限公司,浙江宁波315327

出　　处：《汽车零部件》2024年第11期24-27,31,共5页Automobile Parts

摘　　要：首先根据车辆故障提示码ECM-P040477拆解发动机排气再循环(EGR)系统,发现EGR阀发生腐蚀,阀板与阀体卡滞失效。随后详细分析了EGR阀的腐蚀卡滞机制,通过分析发现:冷凝水的产生是EGR阀等零部件发生腐蚀的根本原因,其形成主要与饱和水蒸气、环境温度和湿度、EGR气体的排气压力、EGR率及汽油质量等因素有关;汽油中的硫化物、氮化物、氯化物等在冷凝水作用下易形成强酸,具备强腐蚀性,易发生电化学腐蚀;氯离子较硫酸根、硝酸根等离子半径较小、穿透和吸附能力较强,对EGR阀腐蚀起主导作用。最后,对EGR阀等零部件提出了腐蚀防护措施,包括减少冷凝水的产生、添加催化剂、选择合理材料、对材料表面进行改性处理等。Firstly,according to the vehicle fault prompt code ECM-P040477,it was found during the disassembly of the engine exhaust gas recirculation(EGR)system that the EGR valve was corroded,and the valve plate and valve body were stuck and failed.Then,by analyzing the working principle of the low-pressure EGR system,this article provided a detailed analysis of the corrosion and sticking mechanism of the EGR valve.Through analysis,it was found that the generation of condensed water is the fundamental cause of corrosion in components such as EGR valves.The formation of condensed water is mainly related to factors such as saturated water vapor,ambient temperature and humidity,exhaust pressure of EGR mixed gas,EGR rate,and gasoline quality.Sulfides,nitrides,chlorides,etc.in oil products are prone to form strong acids under the action of condensed water,possessing strong corrosiveness and prone to electrochemical corrosion.Chloride ions have a smaller radius and stronger penetration and adsorption capabilities compared to sulfate and nitrate ions,and play a dominant role in the corrosion of EGR valves.Finally,some measures have been proposed for corrosion protection of components such as EGR valves,including reducing the generation of condensed water,adding catalysts,selecting appropriate materials,and modifying the surface of materials.

关 键 词：排气再循环(EGR) 冷凝水 零部件腐蚀 腐蚀防护 

分 类 号：U464.149[机械工程—车辆工程]