不同工况下活塞二阶运动和活塞裙部润滑研究

On the Piston Secondary Motion of Piston and Lubrication of Piston Skirt at Different Operating Conditions

目前研究内燃机活塞二阶运动和活塞裙-缸套摩擦副润滑时一般仅针对标定工况进行,不考虑实际使用内燃机工作中工况的不断变化。另外,分析中一般都假设活塞裙-缸套摩擦副在一个内燃机工作循环中处于充分润滑状况。以某四行程内燃机为研究对象,基于实测的气缸压力,考虑实际润滑油流动确定摩擦副的润滑状况,进行不同内燃机工况下的活塞二阶运动和活塞裙-缸套摩擦副润滑分析。结果表明,不同工况下的活塞二阶运动性能和活塞裙-缸套摩擦副润滑性能都存在差异,活塞二阶运动性能和活塞裙-缸套摩擦副润滑性能的最不利情况不一定出现在标定工况。因此,内燃机活塞组件设计时,如果仅分析标定工况下的活塞二阶运动和活塞裙-缸套摩擦副润滑性能将不够全面合理,需要进行不同工况下活塞二阶运动和活塞裙-缸套摩擦副润滑性能的分析计算。

Current research on the piston secondary motion and the lubrication of piston skirt-cylinder liner friction conjunction for internal combustion engine is generally carried out in rated operating condition,and the constant change of operating condition for actual used internal combustion engine is not considered.In addition,the piston skirt-cylinder liner friction conjunction is usually supposed to be lubricated sufficiently in all strokes of an operating cycle of internal combustion engine in current analysis.A four-stroke internal combustion engine is taken as the studying object,based on measured cylinder pressure,the piston secondary motion and the lubrication of piston skirt-cylinder liner friction conjunction considering the lubrication status determined by the actual flow of lubricating oil in different operating conditions of internal combustion engine are analyzed.The results show that there are the differences of the piston secondary motion and the lubricating characteristics of piston skirt-cylinder liner friction conjunction in different operating conditions,and the worst condition may not be in rated operating condition.Therefore,it is not comprehensive and reasonable that the piston secondary motion and the lubrication of piston skirt-cylinder liner friction conjunction are analyzed only in rated operating condition,and it is necessary to calculate the piston secondary motion and the lubrication of piston skirt-cylinder liner friction conjunction in different operating conditions in the design of piston set.