Effects of lubricant shear thinning on the mixed lubrication of piston skirt-liner system

A theoretical analysis is presented for the mixed lubrication of the piston skirt-liner system. The model is developed to consider the shear thinning effect of multigrade lubricant. The friction characteristics of the piston skirt-liner system for both monograde and multigrade lubricants are investigated. It is found that a decrease in the lubricant viscosity is effective in reducing the friction loss. However, the boundary friction at the expansion stroke will increase with low lubricant viscosity. Results in this study show a significant lubricant shear thinning effect on the piston skirt-liner system.