为研究某发动机活塞底部强制喷油冷却对活塞在缸内二阶运动和受力的影响，采用硬度塞测温法获得活塞表面的单点温度数据，借助有限元法求取活塞和缸套的温度场和热变形场，并进一步采用多体动力学分析强制冷却前后不同热变形下活塞的二阶运动和受力。研究结果表明，采用强制冷却后活塞的温度梯度减小，相应的热变形量也随之减小。活塞的横向运动、绕活塞销的摆动由于受到热变形量减小的影响，其运动幅度峰值分别增大25%和27.8%，而活塞与气缸之间的作用力峰值增加36.8%，明显加剧对活塞裙部的磨损。

To study the influence of forced cooling on the secondary motion and force of piston, this research measured discrete temperature on the surface of the piston by hardness bolt, simulated temperature and deformation field with finite element method software, and analyzed the secondary motion and force in different deformation through multi-body dynamics method. The results show that：The temperature and deformation with forced cooling differ from the original one with decreased temperature and deformation range. Due to those changes, the max amplitudes of the piston’s lateral motion and swing around the pin increase with 25% and 27.8% respectively, while the force acted on the piston increase by 36.8% which results in the abrasion deterioration on the piston shirt.