Predicting frictional losses generated by piston connecting-rod big end journal bearing for an internal combustion engine

Abstract

The aim of the study is to investigate the tribological behaviour of the connecting-rod big end journal bearing under dynamic loading for a full engine cycle.In this study, a numerical analysis is used for solving the 2-D Reynolds equation based on Reynolds boundary condition. The 2-D Reynolds solution was derived by using a combination of approaches, namely finite difference method, Newton-Raphson method, and Taylor expansion series. Then, the formulated 2-D mathematical model is used to ascertain the tribological behaviour for both rigid and deformable bearing assumptions.For low loading conditions, the simulation results from both rigid and deformation models have only shown minor differences, demonstrating correlation with existing analytical and experimental results. However, once the loading capacity is increased, the simulation results from the deformation model assumption is shown to be much closer to the experimental results obtained from real engine analysis.In short, an elastic journal bearing assumption in simulating such tribological conjunction is believed to be more practical and reliable for real engine practices as compared to a rigid journal bearing assumption.