计及机体变形的内燃机主轴承弹性流体动力润滑分析

针对某四行程四缸内燃机曲轴主轴承,考虑机体变形因素的影响,进行了曲轴轴承弹性流体动力润滑分析.计算中采用动力学法进行曲轴轴承的润滑分析,采用变形矩阵法计算油膜压力作用下轴承表面的变形.结果表明,与不考虑机体变形影响相比,计入机体变形影响时轴承轴心轨迹基本没有改变,在1个工作循环中的大部分时间轴承最大油膜压力、最小油膜厚度、端泄流量和轴颈摩擦系数几乎没有变化,仅在某些时刻附近轴承最大油膜压力略有减少,轴承最小油膜厚度略有增加.因此在计算精度要求不是非常高的情况下,曲轴主轴承润滑分析可以不考虑轴承表面因油膜压力作用产生的弹性变形的影响.

Elastohydrodynamic Lubrication Analysis of Main Bearing for Internal Combustion Engine Considering Block Deformation

The analyses of elastohydrodynamic lubrication of crankshaft bearings were carried out considering the deformation of engine block for the main bearings of a four-stroke four-cylinder internal combustion engine. The lubrication of crankshaft bearing was analyzed by kinetics method. The deformation of bearing surface under pressure of oil film was calculated by deformation matrix method. Comparison on with and without considering the deformation of engine block, the journal orbit, maximum film pressure, minimum film thickness, end flow-rate and journal frictional coefficient of bearings showed little variation nearly in one engine working cycle. Only in a certain peroid of one engine working cycle, the maximum film pressures of bearings decreased slightly while the minimum film thicknesses of bearings increased slightly. Therefore, the effect of elastic deformation of bearing surface under film pressure can be excluded in a lubrication analysis of engine main bearing when a high calculation accuracy is not required.