Analysis of diverse simulation models for combustion engine journal bearings and the influence of oil condition

The paper deals with the comparison of different models, from simple to complex, for the simulation of non-stationary response of the journal bearings used in combustion engines. The variety of simulation models covers classical methods from Holland, Butenschoen and numerical methods based on the Hydrodynamic (HD), Elasto-hydrodynamic (EHD) and Thermo-elasto-hydrodynamic (TEHD) lubrication theory. Several crankshaft main bearings and connecting rod big end bearings are investigated. The comparison includes the following bearing parameters: Peak Oil Film Pressure (POFP), Minimum Oil Film Thickness (MOFT) and oil flow. Calculation time is compared, too. Estimation of oil viscosity is discussed over a typical temperature and pressure range found in combustion engines, including the influence of the fuel dilution as an example of the oil aging phenomena.