Effects of piston elastic deformation on piston secondary motion and skirt lubrication characteristics

In order to reveal the effects of the piston elastic deformation on the piston secondary motion and skirt lubrication characteristics, the structural dynamics equations of the piston and liner were established based on the finite element modal reduction method, the piston secondary motion equation, the average Reynolds equation and the possible solid-to-solid contact equation in mixed lubrication were solved iteratively based on the parameters of a single-cylinder diesel engine, and the difference between the skirt lubrication performances with or without considering the elastic deformations of piston was analyzed. The results showed that the elastic deformation configurations of the piston skirt thrust and anti-thrust sides experienced different variations with crank angles and the deformation was significant at work stroke. It could be found that the piston secondary motion quantities including the piston deformation became bigger, when compared with those excluding the deformation of piston, especially at