Numerical analysis of lubrication in a journal bearing by a thermoelastohydrodynamic lubrication (TEHL) model

Abstract

In recent years, in high power, compact, and light weight automotive engines, the bearing load has been increasing and the housing stiffness has been decreasing. The engine bearing performance is significantly influenced by both an elastic deformation and an increase in temperature. Under these harsh operating conditions, an extreme temperature rise of the bearing is expected to occur in the thin oil-film region when the oil-film thickness is not kept thick enough within the bearing. Consequently, the high-temperature rise sometimes causes the bearing to have a seizure. Thus, it is necessary to predict accurately the bearing performance in a design stage. A thermoelastohydrodynamic lubrication (TEHL) analysis could theoretically predict the bearing performance under these harsh conditions with high reliability. In order to clarify the validity of the theoretical TEHL model, a rig test was conducted under dynamic load conditions. The test conditions simulated the connecting rod bearings in real automotive engines. The bearing temperatures in the circumferential direction were measured under various load conditions. The bearing performances at each test condition were calculated by the TEHL analysis including a three-dimensional model. In comparison with the simulation test results, TEHL has a high correlation with the experimental results on the bearing temperature.