考虑结构动态变形的缸套-活塞环润滑建模分析

Analysis of Lubrication Model between Piston Rings and Cylinder Liner Considering Structural Dynamic Deformation

缸套在燃烧冲击和活塞敲击激励下会产生接近表面粗糙度的动态变形,极有可能影响缸套-活塞环组件间的摩擦润滑过程。为了研究缸套动态变形潜在的影响,将动力学仿真获取的缸套内表面的动态变形经过处理后导入到润滑模型中,同时采用数值积分计算的方式对油液压力应力因子和剪切应力因子进行实时计算求解,使仿真计算更加符合实际情况。通过搭建同时考虑缸套变形与油液剪切特性影响的改进润滑模型,计算得到整个工作循环内活塞环上的最小油膜厚度和摩擦力曲线。结果表明:考虑缸套动态变形后的最小油膜厚度和摩擦力曲线出现了明显的波动,而且考虑缸套动态变形后的摩擦力比未考虑之前出现了明显下降。

Under the excitations of combustion shock and piston slap,the dynamic deformation of cylinder liner is close to the surface roughness magnitudes,this may affect the friction and lubrication performance between piston rings and cylinder assemblies. To investigate the potential influences of structural deformations on tribological behaviours of cylinder assemblies,the dynamic deformation of the inner surface of cylinder liner was obtained by dynamic simulation,then introduced into the lubrication model after processing. The pressure stress factor and shear stress factor were calculated in real time using numerical integration to achieve more realistic simulation. An improved piston rings-cylinder liner lubrication model was constructed by considering the effects of cylinder liner deformation and oil shear characteristics,the minimum oil film thickness and friction force curves were obtained by computation throughout the entire work cycle. The results indicate that the minimum oil film thickness and the friction force curves obtained from the improved model manifest some obvious fluctuations,and the friction force shows a significant reduction compared to the original model.