第40卷(2018)第3期结构与可靠性
柴油机.Diesel Engine
Vol. 40(2018)No. 3
某型柴油机锻钢活塞开裂故障分析及改进
钱立宏，戴湘利，束铭宇
（玉柴联合动力股份有限公司，安徽芜湖241080）
摘要：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。
关键词：柴油机；活塞；开裂；结构
中图分类号：TK423.3*3
文献标识码：A
文章编号：1001-4357(2018)03-0034-04
AnalysisandImprovementoftheForgedSteelPistonCrackfor
a CertainType of Diesel Engine Qian Lihong, Dai Xiangli, Shu Mingyu(Y&C Engine Co., Lid., Anhui Wuhu 241080)
Abstract: 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.
Key words: diesel engine; piston; crack; structure
0引言
活塞作为内燃机的核心零部件，承受交变的机械负荷和热负荷，是内燃机中工作条件最恶劣的零部件之一，其性能对内燃机的可靠性及性能与排放有重要影响。近年来，柴油机强化程度和可靠性要求不断提高，其缸内最高燃烧压力越来越高，传统铸铝活塞已不能满足重型柴油机要求，锻钢活塞将逐渐成为一种趋势。
锻钢活塞结构如图1（a）所示，其主要由顶部、环槽区（或称为头部）和裙部三部分组成(2)。锻钢活塞一般设计有内冷油腔，发动机冷却喷钩将机油喷人活塞内冷油腔，机油在其内部振荡、流动，从而带走活塞热量，降低其热负荷[3]；流出的机油通过飞溅进一步润滑连杆小头衬套和活塞销座孔。活塞燃烧室、内冷油腔、内腔顶部、销座以及销座孔如图1（b）、（c）所示。本文后续所述活塞均指锻钢活塞。
收稿日期：2017-10-23
作者简介：钱立宏（1986-），男，工程师，主要研究方向为柴油机结构设计及机械开发，qianlihong@kengine.cn。