Research On Parameters Design And Mechanism Of Surface Texture On The Cylinder Liner In Hydrodynamic Lubrication

Nowadays, people put higher requirements for energy-saving, environmental protectionand high reliability of engine，and reducing the friction loss between piston ring and cylinderliner is an important aspect of improving the mechanical efficiency of internal combustionengine. So the research of the application of surface texture technology in the friction pair ofcylinder liner-piston ring which can improve the friction properties is necessary.Surface textures are technical means which machined with certain sizes, shapes andarrays on frictional surface. In order to study the lubrication and anti-friction mechanism, lookfor the best shape and sizes of the surface textures, this paper analyzed the lubrication effectsof different shapes and sizes under the hydrodynamic lubrication, using the CFD methodbased on navier-stokes equation and numerical solution based on Reynolds equation. Whichprovides some reference for application and study on surface textures.Firstly, the CFD analysis model about surface texture which based on Navier-Stokes(N-S) equation was solved in this paper, where the Fluent software was used. It turned out thatthe left trapezoidal groove which slips right with depth h ’3.375and width d ’0.867leadsto better lubrication results among micro-groove typed textures. And the lubrication effectwill be better if we mixed the left and right trapezoidal groove texture which slips right. Themicro-pit of elliptic paraboloid with depth h’28.75and diameter d ’0.56leads to betterlubrication results among micro-pit typed textures. Comparing these two types of texture wecan found the micro-pit of elliptic paraboloid leads to better lubrication results than that ofsemi-trapezoidal groove. The major factors affect the texture lubricating property are wedgeeffect and backward flow which has a changing center of vortex.Secondly, the model of the hydrodynamic lubrication which based on Reynolds equation was solved by using finite difference method. The results showed that the micro-pit of ellipticparaboloid with the depth of d20mcan lead to better lubrication results, increasing thediameter of the micro-pit properly will be better if they can satisfy the strength requirementson cylinder liner inner surface. At the same time we should try to increase the minimum oilfilm thickness. The major factor affects the texture lubricating property in this part we foundis cavitation.Comparing these two results we found: Increasing the depth and the diameter of themicro-pit properly is beneficial to reduce friction if they can satisfy the strength requirements.Three main factors of the surface texture affect the lubrication are backward flow, cavitationand wedge effect.