EHD analysis of a connecting rod bearing in a high-speed engine

A comprehensive numerical investigation is performed on a connecting rod bearing operating at 6,500 rpm. A procedure is developed to obtain the global deformation of the bearing surface by considering the effects of the inertial forces of the connecting rod assembly, the preloaded bolts and the interference fitted bearing shells. An efficient algorithm is developed to analyze a hydrodynamic lubricated deformed connecting rod bearing. Both the finite element and the finite difference methods are employed in this study.; An investigation of bearing structural deformation is conducted in order to evaluate the lubrication characteristics. The finite element method is applied to solve the elasticity equation of the structure including the contact problem between contacting pairs in a connecting rod assembly. The rod inertia force associated with the gas loading is found to have a significant effect on the variation of the rod bearing shape. This shape variation is commonly ignored in rod bearing analyses.; The performance of the non-circular connecting rod bearing is investigated based on the bearing surface deformation. The finite difference method is employed to numerically solve the Reynolds equation which governs the hydrodynamic pressure profile within the connecting rod bearing. An expression which calculates the oil film thickness using bearing surface nodal coordinates is presented in this study. The bearing surface deformation considerably affects the lubrication characteristics of the connecting rod bearing. It is found that a thinner minimum oil film thickness and a larger peak hydrodynamic pressure are predicted in a deformed connecting rod bearing than in a rigid connecting rod bearing. Multi-peaked hydrodynamic pressure is found to appear as well because of two or more converging-diverging film regions. The study provides a significant enhancement in the understanding of the behavior of the connecting rod bearings of high-speed automobile engines.