【作者】 莫森泉；

【导师】 张勇；

【作者基本信息】 华南理工大学 ， 动力机械及工程， 2010， 硕士

【摘要】 活塞环-气缸套系统的气密性能和润滑摩擦状态对内燃机的整体性能有重大影响,随着功率密度的不断增加,活塞环的摩擦功损失和磨损也越来越严重。基于保证密封,尽量降低摩擦功的出发点,本文对内燃机活塞环—气缸套气体密封系统进行了详细的研究,建立了气体泄漏的理论计算模型,并分析了开口间隙、环间容积及转速对气体泄漏量的影响。针对传统活塞环开口间隙是影响系统泄漏的主要因素,提出一种上下两环配对的新型组合式活塞环来提高气密性,理论计算和搭建的发动机静态气密性试验台的研究结果表明,新型组合式活塞环比传统两气环有更好的密封效果。此外,为研究新型组合式活塞环在摩擦功耗方面的特性,建立了活塞环—气缸套润滑研究模型。对活塞环—气缸套摩擦学系统润滑性能研究时运用混合润滑理论模型,采用二维瞬态平均Reynolds方程与Greenwood和Tripp建立的微凸体接触模型,综合考虑表面粗糙效应、润滑油的粘温粘压及变密度效应,考虑了活塞环—气缸套间接触压力的分布及活塞系统二阶运动的影响,采用雷诺气穴边界条件,使理论分析更切合实际,研究结果更具应用价值与指导意义。结果表明,新型组合式活塞环在摩擦功耗方面表现良好。综合新型组合式密封性能分析、摩擦功耗分析和试验研究的结果,新型组合式活塞环在保证气密性的前提下,可以有效减少摩擦功耗,是对活塞环结构设计的一种有效尝试,也为今后活塞环的设计提供新的思路。更多还原

【Abstract】 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.更多还原