Thermo-elasto-hydrodynamic mixed lubrication analysis of main bearings for high power-density diesel engine

Based on the Reynolds function considering lubrication oil filling rate and Greenwood-Tripp asperity contact theory, as well as mass-conserving boundary condition, the thermo-elasto-hydrodynamic lubrication controlling equations were solved simultaneously with finite different method and finite element method. Taking a main bearing of high power-density diesel engine as a example to conduct the thermo-elasto-hydrodynamic mixed lubrication study. Through analyzing the mechanism of the influence of power boost on bearing performance, the structural parameters need to be improved were determined. The influences of bearing lubrication performance at different oil hole positions, elliptic oil holes, shell surface roughness and lubrication oil grades were studied. Through reasonable matching the structure parameters, the minimum oil film thickness increases by 45.04%, peak contact pressure decreases by 76.85%, and average asperity friction loss power decreases by 76.62%. It is shown that the minimum shear rate is an important dynamic indicator to evaluate bearing lubrication property, surface roughness have deterrent effect on oil-film oscillation, oil hole has great effect on bearing lubrication performance. Thus, matching the structural parameters reasonably is significant.