Study On Anti-Friction Performance Of Compound Lubricated Structure Under Oil Lubrication

Cylinder liner-piston ring friction pair is one of the most rubbing pairs in internal combustion engine,and its reliability and durability have always been the focus of attention.The dead zone of cylinder liner works in the environment of high mechanical load and heat load,its lubrication conditions is poor,and always have high friction,when the engine starts frequently prone to severe wear or even pull cylinder.The composite lubricating structure combines the surface texture with the solid lubricant,and the solid lubricant stored in the surface texture can be released to the friction interface in the friction process,which can improve the lubricating performance and exert a good antifriction effect.The alloy plated iron cylinder liner is taken as the research object in this paper,the compound lubricating structure was designed and constructed in the region of the cylinder liner’s dead zone based on the research of the arrangement of micro-pit textures and the treatment of filler materials.The effects of diameter,area rate,depth,distribution angle of micro-pit textures and the types of solid lubricants on the tribological properties of the friction pairs were investigated by reciprocating friction and wear tester under the condition of supplying lubricating oil.The main conclusions are as follows:(1)When the diameter of the micro-pit increases,the storage of the solid lubricant increases,and when the solid lubricant is dragged onto the surface of the cylinder,the range of action becomes larger.When the solid lubricant is mixed with the lubricating oil,The process is easy to fly,and difficult to fix the problem in the micro-pit;the solid lubricant and the lubricating oil are mixed and filled,which can effectively solve the problem that the nano powder is easy to fly in the filling process and difficult to fix in the micro pit.(2)The friction and wear test results show that,the diameter and area ratio of the micro-pit have a significant effect on the friction performance,and the depth and distribution angle of micro-pit have little effect on the friction performance.When the micro-pit’s diameter is 0.7mm,the area ratio is 15.58%,the depth is 0.3mm and the distribution angle is 56°,the friction coefficient is the smallest,which is about 11.81%lower than the untreated original cylinder.(3)In the process of friction and wear,solid lubricant,lubricating oil,micro-pit texture plays a synergistic role in friction reduction.The compound lubricating structure on the surface of the cylinder liner can effectively reduce the abrasive wear.(4)Among the solid lubricants tested,Cu in soft metal solid lubricants,MoS2 and CuO in metal compound solid lubricants all have remarkable effect on reducing friction,and the friction coefficient decreased about 11%compared with the untreated original ones.