某型TGDI汽油机活塞销孔划伤原因分析

Analysis of Scratching Causes of Piston Pin Holes for A Certain Type of TGDI Gasoline Engine

涡轮增压缸内燃油直喷(Turbo Gasoline Direct-Injection,TGDI)汽油机以其高效的性能逐渐成为车用发动机的主流。由于热负荷和缸内压力高于传统的进气道喷射(Port Fuel Injection,PFI)汽油机,开发过程中对TGDI汽油机的耐久性考核强度也高于PFI汽油机。合理的耐久试验故障排查思路可以减少资源浪费,提高发动机的开发效率。本文针对一台2.0L TGDI汽油机冷热冲击耐久试验中出现的活塞销孔划伤故障,进行了详细的故障成因分析和排查,包括失效零部件强度计算校核、缸内最大燃烧爆发压力(爆压)测试、尺寸和装配工艺校核、失效表面分析等,发现零部件装配表面清洁度不达标是导致失效的原因,改进之后进行试验验证,证实上述分析是正确的。本文可为TGDI汽油机耐久试验故障排查提供经验参考。

TGDI gasoline engine has gradually become the mainstream of vehicle engines because of its efficient performance.As the heat load and cylinder pressure are higher than those of the traditional PFI gasoline engine,the durability assessment intensity of TGDI gasoline engine in the development process is also higher than that of PFI gasoline engine.Reasonable troubleshooting ideas for durability test can reduce the waste of resources and improve the efficiency of engine development.In this paper,the causes of the piston pin hole scratch fault in the cold and hot shock durability test of a 2.0L TGDI gasoline engine are analyzed and checked in detail,including the strength calculation and verification of the failed parts,the test of the maximum combustion explosion pressure(explosion pressure)in the cylinder,the verification of the size and assembly process,and the analysis of the failure surface.It is found that the failure is caused by the non-standard cleanliness of the assembly surface of the parts.After the improvement,the test verification is carried out,It is confirmed that the above analysis is correct.This paper can provide experience reference for troubleshooting TGDI gasoline engine durability test.