A Hybrid Solution Scheme for Performance Evaluation of Crankshaft Bearings

In the past few decades the research efforts towards efficient solutions of crankshaft bearing using both rapid (e.g., analytical, semi-analytical, curve fits) and rigorous numerical approaches have made sufficient progress. Analytical solutions compromise on accuracy. In contrast numerical methods require very high computational time and facilities with large memory requirements. These features make it very difficult to obtain a solution that is optimal with respect to memory requirements, computational speed and accuracy. Therefore, here a hybrid procedure for thermal analysis of crankshaft bearings is attempted, which uses a combination of both the analytical and numerical solution techniques. Operational parameters such as journal velocity and effective viscosity are calculated with reasonable accuracy using analytical method. Other parameters such as maximum pressure, oil-flow, and power loss are evaluated by numerical technique. Experiments to validate the proposed hybrid procedure are performed, by developing a test rig that simulates the speed and load conditions usually encountered in practice. A number of experiments at different speeds and loads are performed to check the reliability of the global energy balance (based on effective viscosity assumption) in dynamically loaded bearing. The hybrid methodology is described by a flow chart and can conveniently be programmed on a personal computer. The predictions of two crankshaft main bearings using the proposed methodology are compared with those obtained by rigorous transient thermohydrodynamic (THD) analysis. [S0742-4787(00)02103-2]