考虑热变形的活塞组件结构对活塞二阶运动的影响分析

结合活塞、缸套工作温度场的实测值,建立了2D25柴油机活塞组件动力学模型,分析了配缸间隙、活塞销偏置量和活塞头部型线等结构参数对活塞二阶运动的影响关系,并采用正交试验设计优化了2D25柴油机活塞组件结构参数。分析结果表明:对活塞二阶运动的影响主要体现在活塞敲击能量和摩擦功耗,其影响关系是此消彼长的;在计算的影响因素中,对活塞二阶运动影响最大的是配缸间隙,其次是活塞销偏置量和裙部椭圆度,影响最小的是中凸点位置;活塞头部结构的不同主要是影响活塞敲击能量,而对活塞的摩擦功耗影响较小。

Effect of Piston Set Structure on Piston Secondary Motion Considering Thermal Deformation

Based on measurement of temperature filed of piston and cylinder liner,the dynamic model of piston set in model 2D25 diesel engine was established using AVL Excite Piston and Rings.On the basis the effects of radial clearance between piston and cylinder inner wall,convex position and ovality of piston skirt profile,offset of piston pin and piston head profile on the piston secondary motion were analyzed,and these structural parameters were optimized by using orthogonal experimental design.The results indicate that the piston knock energy and friction power loss are the mainly evaluation indicators of piston secondary motion and their effects are opposite each other.Of them,the radial clearance between piston and cylinder inner wall gives the greatest impact on the piston secondary motion,followed by the offset of piston pin,then the piston skirt ovality,the least is convex position of piston skirt profile.Piston head profile mainly affects piston knock energy,hardly affects the friction power loss.