织构类型对活塞润滑性能影响的数值分析

Numerical Analysis of Effect of Texture Type on Lubrication Performance of Piston

作为内燃机的关键部件,活塞-缸套间的润滑性能可以有效改善整机的动力性和经济型。从流体润滑基本理论出发,通过流场特性分析,结合雷诺方程和膜厚方程,比较了相同深度的圆形凹坑织构和三角形凹坑织构对内燃机活塞-缸套摩擦副之间的润滑减摩性能的影响。结果表明:圆形凹坑微织构较三角形微织构可以产生更明显的动压减摩效应,而三角形凹坑微织构对润滑油膜内产生的空化效应更明显。进一步对比圆形织构和三角形织构的承载力和摩擦系数发现:三角形织构形成的承载能力整体小于圆形凹坑微织构下的承载能力,在前半个周期约为圆形织构的68%,在后半个周期内约为圆形织构的82%;相同工况下,圆形织构的摩擦系数约为三角形微合织构的30%~50%,在上下止点处两者的摩擦系数接近。

As a key component of internal combustion engine, the lubrication performance between piston and cylinder liner can effectively improve the dynamic and economic performance of the whole machine. Based on the basic theory of fluid lubrication, through the analysis of flow field characteristics, combined with Reynolds equation and film thickness equation, the influence of circular pit texture and triangular pit texture on the lubrication and friction reduction performance of piston-cylinder liner friction pair in internal combustion engine is compared. The results show that the circular pit micro-texture can produce more obvious dynamic pressure friction reduction effect than the triangular micro-texture, while the triangular pit micro-texture has more obvious cavitation effect on the lubricating oil film. Further comparing the bearing capacity and friction coefficient of circular texture and triangular texture, it is found that the bearing capacity of triangular texture is smaller than that of circular pit micro-texture, which is about 68 % of that of circular texture in the first half cycle and about 82 % of that of circular texture in the second half cycle. Under the same conditions, the friction coefficient of circular texture is about 30%~50% of that of triangular micro texture, and the friction coefficient is close at the upper and lower stop points.