Study on the lubrication of piston skirt-cylinder liner under the engine working conditions of different speeds and loads

The working condition (speed and load) of internal combustion engine is one of important factors affecting the lubrication performance of piston skirt-cylinder liner. In actual normal use, the working condition of internal combustion engine is constantly changed under different speeds and loads. However, the current lubrication performance of piston skirt-cylinder liner is analyzed generally under only one or several working conditions of internal combustion engine, in which the working conditions does not cover full range of different engine speeds and loads. In addition, it is generally assumed in current studies that the piston skirt is fully lubricated in all strokes of an engine working cycle. In this paper, a four-stroke internal combustion engine is taken as the research object, the lubrication performance of piston skirt-cylinder liner under full working condition range of internal combustion engine with different engine speeds and loads are analyzed, in which the lubrication status of piston skirt is determined by considering the actual lubricating oil transport. The results show that there are differences in the lubrication performance of piston skirt-cylinder liner under different working conditions of internal combustion engine. The rated working condition of internal combustion engine may not be the most unfavorable working condition to the lubrication performance of piston skirt. Therefore, it is necessary to analyze the lubrication performance of piston skirt under full working condition range of internal combustion engine with different speeds and loads when the piston assembly is designed.