Research On Hydrodynamic Lubrication Of Crankshaft Bearings In Internal Combustion Engines

Crankshaft bearings are critical movement components in ICE, which directly affect the performance reliability and the whole life of the engine. It has important significance when making research of the crankshaft bearings lubrication. In this paper, for a 4-cylinder diesel engine vehicle used, it makes a comprehensive study of hydrodynamic lubrication of the crankshaft bearings.In the base of the hydrodynamic lubrication theory on sliding bearings, it puts the research line of the crankshaft bearings lubrication. In the dynamics of the engine crank train analysis, it gains the load on the crankshaft bearings, and for load the main bearings separated with the determinate method and indeterminate method. After summarizing Hahn Method, Holland Method and Mobility Method, in the assumption of rigid and smooth surface, it makes orbital path calculation using the finite length bearing model with Mobility Method.Because the elastic deformation and the surface roughness can't be ignored, it considers the elastic deformation of the bearing wall, back steel, alloy steel, and the surface roughness of the journal and the shell, and makes a coupling analysis of oil film thickness, oil film pressure, elastic deformation, surface roughness when using the finite difference method and the finite element method. When compared with HD and ES (as a material, divided into Vanuatu back and antifriction alloy layer), we found that EHD analysis is more accord with the actual conditions. The elastic deformation factors are considered more fully, the greater the amount of elastic deformation, the greater the value of the film thickness, then the smaller oil pressure.Meanwhile, when considering the region of the oil groove, the relative clearance, the oil, the bearing width and other parameters on the engine crankshaft bearings, the paper makes a detailed EHD study. The results show that these parameters are significant effect to the bearing lubrication properties. It can be contributed to the optimal design of bearings if these factors are considered adequately.The analysis results show that the EHD study ,which considering the elastic deformation of the bearing wall, back steel, alloy steel, and the surface roughness of thejournal and the shell ,is more accord with the actual conditions. If coupling elastic deformation and surface roughness analysis, and considering the region of the oil groove, the relative clearance, the oil, the bearing width and other factors in the design of the crankshaft bearings lubrication, it would be great significance to the reliability of the ICE.