温度对缸套-活塞环摩擦性能的影响

Effect of Temperature on the Friction Performance of Cylinder Liner-Piston Ring

LNG燃料柴油机与传统燃料柴油机相比缸内燃烧温度更高。为探究不同温度下缸套-活塞环摩擦性能与温度的映射关系,设计室温和60、90、120℃4种不同温度,在相同载荷和转速下在往复式摩擦磨损试验机上对缸套-活塞环进行不同温度下的摩擦性能试验,通过测试摩擦过程中摩擦力的变化以及分析试验后缸套磨损表面形貌,探讨温度对缸套-活塞环摩擦性能的影响规律。试验缸套试样材质为耐磨合金铸铁,活塞环切片与缸套切片大小对应,材质为球墨铸铁。试验结果表明:随着温度的升高摩擦力呈现先减小后增大的趋势,与室温相比,60℃温度下摩擦力降幅为13.45%,且表现出较好的稳定性,但在120℃下摩擦力增幅为10.66%;试验工况下,60℃时缸套表面形貌参数均处于较优水平。研究表明,适当的温度环境对于摩擦配副之间的润滑性能有一定的促进作用,但温度过高会导致摩擦副的摩擦性能不稳定,破坏摩擦副间氧化膜,这不仅可能破坏润滑油膜的形成,也会影响摩擦副的磨损表面形貌。因此存在合适的温度使得缸套-活塞环的摩擦性能达到最优状态。

LNG fuel diesel engine has higher combustion temperature in the cylinder compared with traditional fuel diesel engine.In order to explore the mapping relationship between cylinder liner-piston ring tribological performance and temperature,four different temperatures were designed,namely room temperature,60℃,90℃and 120℃,the cylinder liner-piston ring friction performance at different temperatures was tested on a reciprocating friction and wear tester under the same load and speed.The effect of different temperatures on the friction performance of cylinder liner-piston ring was analyzed in terms of the friction force change in the friction process and the worn surface morphology of the cylinder liner after the friction test.The material of cylinder liner specimen was wear-resistant alloy cast iron,and the size of piston ring specimen corresponds to that of cylinder liner specimen,and the material of piston ring specimen was ductile iron.The test results show that the friction force shows a first decreasing and then increasing trend with the increase of temperature.Compared with room temperature,the friction force decreases by 13.45%at the temperature of 60℃,and shows good stability.However,the friction force increases by 10.66%at the temperature of 120℃.The surface morphology parameters of the cylinder liner surface are at a superior level under the test conditions at 60℃.The results prove that an appropriate temperature environment has a certain promotion effect on the lubrication performance between the friction mating pairs.However,too high temperature will lead to unstable friction performance of friction pairs and damage the oxide film between friction pairs,which may not only damage the formation of lubricating oil film,but also affect the wear surface morphology of the cylinder liner.Therefore,there is a suitable temperature to make the friction performance between cylinder liner and piston ring reach the optimal state.