Abstract: The paper built a numerical model for analyzing friction of piston ring-liner system, which considered the influence of cavitation and mixed lubrication. To investigate the synergistic effect of low viscosity and surface texture, two types of low viscosity oils, i.e. SAE0W20 and SAE5W20, were selected. Besides, the friction of piston ring with spherical texture, which was with a radius of 30μm and a depth of 3μm, was compared to the friction of piston ring without surface texture. The results show that the impact of surface texture is closely related to the viscosity of lubricating oil. Under condition of lubricating oil SAE0W20, the spherical texture helps to reduce friction, while under condition of lubricating oil SAE 5W20, the spherical texture increases friction power loss and friction mean effective pressure.

Key words: piston ring-liner system; low viscosity oil; surface texture; friction characteristic; mixed lubrication