表面形貌对活塞环密封及摩擦性能的影响

综合考虑活塞环表面形貌、弹性变形、运动面型线影响,建立柴油机活塞环-缸套摩擦副的弹性流体动压润滑计算模型,分析活塞环表面纹理方向及粗糙度大小对活塞环窜气及摩擦功耗的影响。研究发现,随着转速的提升,活塞的窜气量及摩擦功耗会加剧,导致发动机效率降低;活塞环-缸套摩擦副的表面纹理方向影响窜气量和摩擦功耗,采用活塞环横向纹理和缸套纵向纹理配合时,对活塞环窜气量及摩擦功耗的改善效果较好;活塞环和缸套的表面粗糙度对密封和润滑特性有较大影响,当缸套表面粗糙度增大时,窜气量先减小后增大,摩擦功耗先增大后减小,而在一定范围内,当活塞环表面粗糙度增大时,窜气量和摩擦功耗都减小。

Influence of Surface Morphology of Piston Ring on Its Friction and Sealing Performances

Considering the influence of piston ring surface texture,elastic deformation and moving surface profile,a calculation model of elastohydrodynamic lubrication for piston ring cylinder liner friction pair of diesel engine was established.The influence of texture direction and roughness of the piston ring surface on air channeling and friction power loss were analyzed.It is found that with the increase of the engine speed,the piston air channeling and friction power loss will increase,resulting in the reduction of engine efficiency.The direction of surface texture of piston ring and cylinder liner friction pair affects the air channeling and friction power loss.There is a better improvement effect on the piston air channeling and friction power loss when the piston ring with a transverse texture is matched with the cylinder liner with a longitudinal texture.The surface roughness of the piston ring and the cylinder liner has a great influence on the sealing and lubrication characteristics of diesel engine.The air channeling is first decreased and then increased,and the friction power loss is first increased and then decreased with the increasing of the surface roughness of the cylinder liner.The air channeling and the friction power loss are both decreased with the increasing of the surface roughness of the piston ring in a certain range.