Abstract: The transport of lubricating oil between the piston skirt and the cylinder liner has important influence on the lubrication status of piston assembly frictional pair, the consumption of lubricating oil, the emission and the performance degradation of lubrication oil. Based on the models of piston secondary motion, fluid lubrication and lubricating oil flow, the transports of lubricating oil between the piston skirt and the cylinder liner at the different engine conditions are calculated. The detained lubricating oils on the surface of cylinder liner behind the movement of piston skirt in the strokes in which the piston moves downward are analyzed mainly. The results show that the change rule of detained lubricating oil is same basically in the corresponding stroke at different operating cycle, the detained lubricating oil is different at different time, and the detained lubricating oil is same basically at the top and bottom dead center. Under the condition of same load of engine, when the speed increases, the detained lubricating oil in the intake stroke and the middle and later stage of expansion stroke will decrease and the detained lubricating oil in the earlier stage of expansion stroke will increase. Under the condition of same speed of engine, the detained lubricating oil in the earlier stage of expansion stroke will increase generally with the increase of load, the detained lubricating oil in the middle and later stage of expansion stroke will not change basically against the load, and the detained lubricating oil in the intake stroke will have different change rule against the load in the different speed.

Key words: cylinder liner, lubricating oil, piston skirt, transport, internal combustion engine