Mechanism Research On Impact Of Cylinder Liner Surface Parameters On Lubrication Performance And Oil Evaporation Consumption

With the requirements of high efficiency energy conservation and ultra-low emission of the internal combustion engine,the research on the low friction is becoming more and more urgent.Among them,the laser surface texture on the cylinder-piston ring crucial friction pair have got more and more attention by domestic and foreign scholars.However,only the optimal matching of texture parameter and the size and distribution function of roughness in non-texture regions,can the friction pair achieve the comprehensive effect of improving lubrication and friction,but the difference of cylinder surface roughness characteristics anter different machining technology and process are obvious,and the optimize of the allocation is to be further clear.Therefore,in order to solve this problem,a series of theoretical and experimental studies are carried out to provide theoretical basis and technical support for the development of texture technology.Taking into account the non-texture area roughness size,roughness probability distribution,mixed lubrication theory model and oil evaporation consumption calculation model of textured cylinder-piston ring friction pair are established,and the variation of the multi-grid methods are used to solve equations.Basing on the theoretical model,the influence of the average roughness and the roughness probability distribution of original mechanical surface(non-textured area)on the lubrication performance of the non-texture cylinder liner and the textured cylinder liner are simulated,and the differences are determined.The optimal parameters of the original mechanical surface are decide.The results show that for the texture cylinder liner,lubrication performance is better when the roughness of the non-texture area has a negative skewness(Sk<0)and lower roughness.The roughness probability distribution of the non-texture area and texture parameters are optimized to improve the friction performance and oil consumption.The results show that the lubricating performance decreases with the increase of the surface skewness and kurtosis,with the increase of the radius of the dimples,the rate of oil evaporation increases continuously and the rate of increase is fast in stare and then slow down.There are optimal texture area rate and depth making the lowest oil evaporation.Synthetic considering the oil consumption performance and lubrication performance,average roughness Ra=0.2-0.3?m,non-texture area parameters Sk=-5~-3,Ku=3~5 the texture region parameters rp = 25~40?m,Sp = 0.2~0.4,hp = 4~6 ?m.According to the simulation results,the cylinder liner with small roughness and near probability Gaussian distribution(mirror cylinder liner)and platform honing cylinder liner are selected,and the different texture schemes in the above parameters range are processed and installed.Reverse drag tests and oil consumption tests are conducted.The results show that the oil consumption of the large depth cylinder is larger than the small depth cylinder.Both too large and too small area occupancy rate have adversely affect the oil consumption.In addition,the oil consumption of the platform honing cylinder liner is slightly higher than the mirror cylinder,The reason may be that the irregular groove of cylinder liner surface storage more lubricants.The results of reverse drag tests show that the lubrication of the mirror cylinder liner is worse than the platform honing cylinder liner,and the advantage of the platform honing cylinder liner in the medium and low speed zones are more obvious.But after texture process on mirror cylinder liner,the lubrication performance is better than the platform honing cylinder liner.The effect of the small depth-diameter ratio is better than the large depth-diameter ratio case at all test speed conditions.The friction torque of the medium area occupation rate is the lowest.The lubrication of too small and too large area occupation rate cases are negative.All above test results are in good agreement with the results obtained from simulation,which verifies the accuracy of the model.