内燃机活塞裙部的流体动力润滑特性

在最小油膜厚度不能小于气缸壁面和裙部表面粗糙度的前提下，用有限元方法解雷诺方程，得出分布的油膜压力。用油膜压力合力与侧压力是否平衡来判断裙部型面的设计是否合适，在计算过程中还考虑了活塞的摆动、横向位移以及中凸点附近曲率的影响。

Hydrodynamic Lubricating Characters of Piston Skirt Profile in Internal Combustion Engine

To choose an optimum profile of piston skirt is the purpose of the research, with which the hydrodynamic lubricating between piston skirt surface and cylinder liner must be very effective. First, an oval-hyperboloid was employed to express piston skirt surface in working conditions. Second, the Reynolds equation, with which the lubrication of piston skirt was described, was solved with FEM. Good behavior of hydrodynamic lubricating between piston skirt and liner should satisfy the following two criterions: (1) the resultant of hydrodynamic pressure and the thrust force were equilibrant; (2) minimal thickness of oil film was larger than the sum of roughness of piston skirt surface and cylinder liner. Finally, The optimum profile of piston skirt was decided through computer program. The swinging and lateral velocities of piston, the place of the center of piston pin and the curvature of the piston skirt surface were also taken into account.