某型柴油机锻钢活塞开裂故障分析及改进

针对某型柴油机试验过程中活塞燃烧室底部位置出现开裂、穿孔,造成发动机漏气量急剧上升,活塞内腔顶部发黑严重故障,对活塞进行理化分析和FEA分析。分析结果表明:故障的主要原因是活塞内冷油腔结构设计不合理,造成燃烧室底部位置结构强度不够及内冷油腔冷却效果不足。据此提出改进措施,改进后的活塞经FEA分析及台架试验验证:其结构强度得到明显改善,满足使用要求。

Analysis and Improvement of the Forged Steel Piston Crack fora Certain Type of Diesel Engine

As cracks and perforation appeared in the bottom of the combustion chamber during the test of a certain type of diesel engine, which lead to rapidly increase of air leakage and the inner cavity of the forged piston was severely black, physical and chemical analysis and FEA analysis were carried out on the piston. The analysis results showed that the main cause was that the structure of the inner cooling oil chamber of the piston was not well designed, and therefore the structural strength of the combustion chamber bottom, as well as the cooling effect of inner cooling oil chamber were not sufficient. Based on the research, improvement solutions were given. The optimized piston was verified by FEA analysis and bench test. It shows that its structural strength is obviously improved and could meet with the application requirements.