吴 东，杨运平

（重庆潍柴发动机有限公司，重庆 402262）

摘要：某型柴油机单缸功率由140kW提升到150kW后，活塞出现了拉缸问题。针对该问题，本文从增强活塞的冷却入手，基于活塞的冷却方式及冷却油道结构等方面进行分析，对机油供油压力、供油喷孔大小及活塞进、出油口尺寸进行了优化改进；通过CFD仿真计算，活塞油腔的机油填充率从优化前的34%提高到优化后的46%，接近50%的理想机油填充率；最终经柴油机耐久试验验证：活塞冷却良好，无拉缸现象。

关键词：柴油机；活塞冷却；机油填充率

Abstract: With the power per cylinder of a certain diesel engine increased from 140kW to 150kW, cylinder-scoring caused by piston happened. In order to solve the problem, piston cooling is increased by optimizing oil supply pressure, orifice size of oil jet, as well as inlet and outlet size of piston oil passage based on analysis of piston cooling method and structure of cooling oil passage.With the aid of CFD simulation, oil filling ratio in oil chamber in the piston is increased from 34% before the improvement to 46%, approaching the ideal oil filling ratio of 50%. Finally, durability testing of this diesel engine model shows that piston cooling is enough with the improved design, and there is no more cylinder-scoring.

Keywords: Diesel Engine；Piston Cooling；Oil Filling Ratio