A Study of Dynamically Loaded Engine Bearings Using a Transient Thermohydrodynamic Analysis

Abstract

A comprehensive, transient thermohydrodynamic (THD) analysis for dynamically loaded journal hearings presented earlier (1) is used to study the performance of dynamically loaded engine crankshaft hearings, i.e., main hearings and connecting rod. bearings. Oil film temperatures are found, to vary considerably over time and space. This variation can he explained, from the journal orbit diagram. A simplified thermal analysis which uses a single effective oil film temperature calculated from overall, energy conservation is also developed. Comparisons are made between the predictions of the full THD analysis, an adiabatic THD analysis and the simplified thermal analysis. The adiabatic THD analysis compares well with the full THD analysis. The simplified thermal analysis compares reasonably well with the full THD analysis and is a significant improvement over an isothermal analysis.