Hydrodynamic Lubrication Analysis Of The Main Bearings In Inner Combustion Engine

Elastohydrodynamic and thermoelstohydyodynamic lubrication analysis for the main bearings of an inline 4-cylinder inner combustion engine are performed, after the fifth main bearing was burnt. According to the obtained results, the reason of burning bearing are analyzed and the improved projects are proposed.According to Reynolds equation, the elstohydrodynamic lubrication model is built which considers the influence of surface roughness, cavity, elastic deformation and viscosity-pressure effect. The comparison and simulation include the following lubrication parameter: minimum oil thickness, peak oil film pressure peak asperity contact pressure and orbital path. As find that there exiting wear on the bearing and point out the reason of bearing wear and improved method. According to the analysis above, the improved projects are proposed, and the elstohydrodynamic lubrication of the improved ones are performed. By comparing the lubrication characteristic of the tow case, it is found that widening the bearing wall is better than thickening the journal.On the basis of the elastohydrodynanic lubrication analysis, combined with energy equation and viscosity-temperature equation, the thermoelastohydrodynamic lubrication model is created, which considers the influence of the oil viscosity change along the oil thickness direction and the viscosity-temperature effect. Then minimum oil thickness, peak oil film pressure, peak asperity contact pressure, oil flow and temperature distribution are studyed to analyze the thermal effect on oil lubrication and the significance in practical application.