乘用车柴油机气缸盖裂纹失效分析及解决措施

Analysis and Solution to the Crack of Cylinder Head of Diesel Engines for Passenger Cars

乘用车用某四缸涡轮增压柴油机在试验过程中出现气缸盖裂纹问题。为解决此问题,首先对裂纹形态进行分析,进而对可能造成裂纹的原因逐一排查,再通过仿真分析、对标分析、试验验证等方法对问题真因进行确认。结果表明:气缸盖整体刚度低及局部结构薄弱导致裂纹处疲劳安全系数低为裂纹产生的原因。针对气缸盖裂纹问题,制定了提高气缸盖整体结构刚度,优化局部结构强度的更改措施。经过仿真分析和试验验证,确认更改措施可以有效避免气缸盖裂纹的发生。

This paper shows a problem of cylinder head crack occurring on a four-cylinder diesel engine.To solve this problem, firstly, it＇s necessary to inspect the form of the crack. Secondly, we need to find out the possible reasons which could cause the cracks. Finally, find out the reason by means of simulation analysis/benchmark and test verification. The test results indicate, the structure rigidity of the entire cylinder head is insufficient and local strength is weak, that caused fatigue safety factor unacceptable,which leads to the crack. Aiming to solve this crack issue, we enhanced the structure rigidity of the cylinder head and optimized the regional structure. At last, we got obvious benefits from this kind of solution verified by test results.