机体弹性变形对主轴承润滑特性的影响

Effects of engine block elastic deformation on the lubrication characteristics of main bearings

为揭示机体弹性变形对曲轴主轴承润滑特性的影响,在考虑整机体和曲轴弹性的条件下,建立发动机曲柄连杆机构多柔体动力学模型,耦合基于质量守恒边界条件的广义雷诺方程和Greenwood/Tripp接触模型,分析机体弹性变形对曲轴主轴承润滑特性的影响。结果表明:与刚性机体相比,计入机体弹性变形后,各主轴承的润滑特性随曲轴转角的变化趋势与将缸体处理为刚性时基本一致;润滑油平均端泄量和总摩擦功耗在一个工作循环内均变化较小;润滑油最小油膜厚度、最大油膜压力和轴承的最大粗糙接触压力在一个工作循环内的某些时刻变化明显。

To investigate the effect of the engine block elastic deformation on the lubrication characteristics of main bearings,a multi-flexible body dynamic model was developed with considering the elastic deformation of the whole engine block and crankshaft.Coupled with the generalized Reynolds equation and Greenwood/Tripp contact model based on the mass conserving boundary condition,the lubrication performances of main bearings were obtained.The results show that when the block elastic deformation is taken into account,the variation trend of the lubrication characteristics are coincident with that without considering the deformation of the engine block;the average of outflow and the total friction power loss show little difference,at the same time,the minimum oil film thickness,the peak oil film pressure and the peak asperity contact pressure have significant variation at certain times of an operating cycle.