Theoretical Study On Piston Ring-Cylinder Contacts With Different Surface Texture

The friction loss caused by piston ring cylinder liner friction pair accounts for about 20% of the total loss of the internal combustion engine.Therefore,a lot of researches have been made on the piston ring cylinder liner friction pairs from the aspects of structural parameters,viscosity and quantity of lubricating oil,surface morphology,contact model of piston ring cylinder liner and so on,in order to improve the friction performance of the pair.In recent years,the researches on improving the contact friction performance of ring cylinder liner by contact surface texture have attracted wide attentions of scholars.Based on the one-dimensional contact model of piston ring cylinder liner by Biboulet et al.[48-50],the influences of the surface texture on the contact pressure and performance of the piston ring cylinder liner are discussed.The main work includes:First,one dimension contact lubrication model of piston ring-oil film-cylinder liner system is established on the basis of one dimensional mean Reynolds equation,and the piston ring cylinder liner friction pair with surface texture.On this basis,a simplified analytical solution for the contact pressure of the piston ring cylinder liner is derived,and the contact pressure between the piston ring and cylinder sleeve is analyzed and compared.The cylinder sleeve with three kinds of surface texture,i.e.single and multiple rectangular,triangular and elliptical textures are derived.The results show that the three surface texture structures on the cylinder have different effects on the distribution and change of contact pressure,and the contact pressure changes in the elliptical surface texture region are more slow than the contact pressure in the triangular and rectangular surface texture regions.Therefore,the elliptical surface texture can better improve the contact pressure distribution of piston ring cylinder liner.In order to optimize the structure parameters and distribution position of the surface texture,the influence of the contact pressure between the piston ring and the cylinder is compared by changing the parameters of the surface texture size and the position distribution of the texture.The results show that when the width of the texture is certain,the contact pressure between the piston ring and the cylinder is inversely proportional to the depth of the texture,that is,the greater the depth of the texture is,the smaller the contact pressure is.When the depth of the texture is fixed,the speed of the contact pressure decreasing in the piston ring and the cylinder is inversely proportional to the width of the texture,that is,the greater the width of the texture is,the slower the contact pressure decreases;when the texture position is reduced,the lower the texture is the texture position.When the middle position is placed,the contact pressure distribution between piston ring and cylinder sleeve can be obviously improved.This work shows that the simplified analytical formula based on the surface texture model are suitable for studying the influence of some typical texture parameters on the contact friction properties of the piston ring cylinder liner friction pair,and provide guidance for the optimization design of the friction pair.Compared with numerical simulation,this method can also reduce the workload of complex numerical computation.