EHD Mixed-Lubrication Analysis of Main Bearings for Marine Diesel Engine Based on Flexible Whole Block

Based on the whole flexible engine block and the flexible crankshaft reduced by CMS method, considering mass-conserving boundary conditions, the average flow Reynolds equation and Greenwood/Tripp asperity contact theory, an EHD mixed-lubrication model of the main bearings for the diesel engine is developed and researched with finite volume method and finite element method. The results show that under the whole flexible block model, maximum oil film pressure and maximum peak contact pressure decrease, while minimum oil film thickness increases. Oil flow over edge decreases, and friction loss also decreases. Therefore, coordination deformation ability of whole engine block is favourable to mean load. In the whole block model, friction contact happens in both upper shell and lower shell positions. So, wearing resistance of both upper and lower shells must be enhanced simultaneously. Therefore, it is very important to predict the mixed-lubrication performance of main bearings accurately, based on the whole flexible engine block.