柴油机全浮式活塞销连接副的运动及润滑特性研究

基于弹流润滑理论、平均流量模型及微凸峰接触理论，综合采用基于模态压缩法的多柔性体和有限差分法耦合求解了某柴油机全浮式活塞销连接副的运动特性及混合润滑特性，并考察了结构表面粗糙度对活塞销轴承摩擦损失功率的影响.结果表明:活塞销的转动角速度较小，在整个做功冲程几乎为0；工作过程中，活塞销轴承大多处于混合润滑状态，仅在吸气冲程和排气冲程连杆摆角最大的时刻附近处于流体润滑状态；可适当减小活塞销（孔）轴承的表面粗糙度来提高活塞销的转速，以显著降低活塞销轴承摩擦损失功率，继而改善润滑状况. 

Study on the Movement and Lubrication Characteristics of Floating Piston Pin for Diesel Engine

Based on the EHL theory, the average flow model and the asperity contact theory, both the finite difference method(FDM)and the multi-body dynamic (MBD) method were used synthetically with component mode to analyze the movement and lubrication characteristics of the floating piston pin for diesel engine. And the effect of the surface roughness on the friction power loss of piston pin bearing was also analyzed. The results show that, the angular velocity of piston pin is small, which is almost zero in the entire power stroke; the piston pin bearing works under mixed lubrication condition in most time, and works under fluid lubrication condition only when the connecting rod''s revolving angle is in maximum at the intake stroke and exhaust stroke. Through appropriately decreasing the surface roughness of piston pin (hole), the angular velocity of piston pin can be increased in the power stroke, and the total friction of piston pin bearing can be reduced significantly, which will improve the lubrication condition of piston pin.