Effect of roundness and coaxiality error on the lubrication performance of ICE main bearings

Nowadays, with higher power density trend and lightweight design requirements in internal combustion engine, more factors are considered in bearing lubrication analysis to improve the lubrication performance and to decrease the risk of failure. The effect of roundness and coaxiality on the lubrication performance of a V-type diesel engine main bearings were investigated systematically and comprehensively using numerical simulation method based on elasto-hydrodynamic lubrication theory. The average flow model, the asperity contact theory and the multi-body dynamics based on component mode synthesis were used to improve simulation accuracy and efficiency. The results showed that out-of-roundness has an apparent negative effect on the lubrication performance of main bearings and the out-of-roundness wave height and the wave number should not exceed 2μm and 10 respectively. In addition, the lubrication performance increased slightly when the bearing house coaxiality tilt angle is the same as the journal load bending direction. The study has some guiding significance for improving the lubrication performance and tolerance requirements design of main bearings.