Study Of Lubrication And Seal Performance For The New Type Of Piston Ring

The seal performance and lubrication and friction state of the piston rings and cylinder liner have a significant impact on the overall performance of internal combustion engines, as the power density of engines increases, friction power loss and wear of piston rings and cylinder liner are more and more serious. On the pursue for maintaining seal performance and minimizing friction power, this paper has been studied in detail on the gas seal system of piston rings and cylinder, established a theoretical calculation model for gas leakage to investigate all the factors which influence gas leakage. Since the open gap of traditional piston rings is the main factor for gas leakage, a pair of upper and lower new composite piston ring are introduced to improve seal performance. According to the results of theoretical calculation and the static state seal performance investigation on the engine test bench, the new composite piston ring has a better seal performance than 2-piston rings seal system.Moreover, a lubrication model which uses mixed lubrication model, average two-dimensional transient Reynolds equation and Greenwood and Tripp's asperity contact model for piston rings and cylinder liner is developed to study the friction power loss characteristic of the new composite piston ring, considering the factors such as the effect of surface roughness, lubricant viscosity-temperature stick pressure and variable density effects, the piston ring - cylinder contact pressure distribution suite and the secondary motion of the piston system and adopting the Reynolds'cavitation boundary condition so that the theoretical analysis is more practical, and the results are of more application worth and significant guidance. The results show that the new composite piston ring has a good performance on friction power loss.The results of seal performance and friction power loss and experimental study on seal performance show that the new composite piston ring can effectively reduce friction power loss in the premise of ensuring seal performance. So the new composite piston ring is not only an effective attempt to the structure design of piston rings but also provides a new way of thinking for design in future.