Study of Cavitation and Wear Damages in Conrod Big End Bearing of a Heavy Duty Diesel Engine by Using Elasto-Hydrodynamic Method

Abstract

Wear and cavitation erosion are the common damages in engine bearing shells. In the case of cavitation damage, the generation and immediate collapse of small gas bubbles cause high pressure pulses and the bearing surface is being locally damaged. Cavitation damage is observed in heavy duty diesel engine due to highly dynamic loading, oscillation of pins, turbulence of oil flow and other factors. Wear damage induces adjustment in the bearing geometry and affects the oil film pressure and the durability of bearing shell. In this paper, wear and cavitation damages in connecting rod big end bearing have been studied. In order to compute the bearing lubrication characteristic such as minimum oil film thickness and maximum oil film pressure, Elasto-Hydrodynamic method that incorporates mass conserving algorithm has been utilized. Wear and cavitation damages in two different designs of connecting rod structure in a heavy duty diesel engine have been assessed and the results have been presented. Furthermore, the effect of connecting rod structure on wear damage has been investigated.