Research On Hydrodynamic Lubrication Of Crankshaft Main Bearings In Internal Combustion Engines

The main bearing is the main friction part of internal combustion engines which bearshigh pressure, high temperature and high rotating speed in working process. If the lubricationis poor, it absolutely will affect the reliability and the lifespan of the internal combustion dueto the friction. It is available to find key factors affecting the working performance, andpredict the bearing performance accurately by research of lubrication of bearing whichprovide references for the best design of bearing lubrication.This paper takes a four-cylinder engine as research subject. Refer to the phenomenon ofbush-burning occurred in power experiments of the fifth main bearing, a method thatcombines AVL-EXCITE multi-body dynamic simulation with ANSYS finite element methodis applied to carry on numerical simulation on the main bearings. The reasons of burningbearing are analyzed and the improvement projects are proposed as soon as obtain the results.The elstohydrodynamic lubrication model is developed based on the sliding bearinghydrodynamic lubrication theory, which takes the influence of surface roughness, elasticdeformation, viscosity-pressure and cavity effect into consideration. We can gain thefollowing lubrication parameters with calculation: minimum oil thickness, peak oil filmpressure, peak asperity contact pressure and orbital path. And find that there exits weary onthe bearing, therefore, two improvement methods proposed by studying the causes of friction.Based on the elastohydrodynamic lubrication analysis, the comparative study of these twoimprovement program was made to improve results of bearing lubrication performance. Bycomparing the lubrication characteristic of the two experiments, it is found that widening thebearing wall is better than thickening the journal.