Connecting rod bearing EHD analysis including inertia effects due to the distributed rod mass

This paper attempts to address the limitations of quasi-static elastohydrodynamic (EHD) bearing lubrication analysis where the structural inertia of the distributed rod mass is neglected. A procedure is outlined where the big-end bearing distortions due to the structural inertia are pre-calculated using the finite element (FE) method and then included in a subsequent EHD analysis via a dynamic deformation file. The effect on results in terms of oil film thickness and pressure are investigated for a 2.0L gasoline engine. A validation is presented showing good comparison of the EHD bore shape with an instrumented engine test and also a full dynamic FE model. The conclusion is made that distributed inertia effects become significant above 3000rpm and that the outlined method is valid for including such effects.