内燃机活塞裙部二次型线的弹性流体润滑分析

On the Elastic Fluid Dynamic Lubrication of Liner-piston System with Quadratic Skirt Profiles

在对活塞动力学和流体动压润滑行为进行耦合建模的基础上,以椭圆曲线为例分析了二次裙部型线对承压油膜形成的影响,并通过仿真计算考察了活塞裙部二次型线下的油膜力及其在活塞两侧的分布、裙部摩擦损失、活塞二阶运动等。通过分析可知,与直线型裙部型线相比,二次型线具有如下特点:裙部与缸套间的多段楔形有利于形成分布更加合理的多段承压油膜,从而有利于活塞的可靠润滑和导向;活塞裙部摩擦损失有所减小;活塞横向运动速度和位移有明显增加等。

The effects of the quadratic skirt profiles on the forming of the bearing force oil film were studied with the coupling model of the piston dynamics and the elastic fluid dynamic lubrication. By simulation, the oil film force and its distribution over the piston skirt, the friction loss of the piston skirt and the secondary motion of the piston were analyzed for elliptical skirt profile, which was taken as an example of quadratic skirt profiles. Comparing with the linear skirt profiles, the quadratic skirt profiles have the following characteristics. For quadratic skirt profiles multiple bearing force oil films can come into being with the multiple wedge shapes existing between the piston and the cylinder liner. This is beneficial for the lubrication and the guide of the piston. The friction loss of the piston skirt can minish for quadratic skirt profiles. The speed and displacement of the piston secondary motion increase obviously for quadratic skirt profiles.