Transient tribodynamic analysis of crankshaft-main bearing system during engines starting up

Abstract

The starting-up process of internal combustion engines presents a great challenge to the tribodynamic performance of the crankshaft-main bearing system. In this study, a transient mixed elastohydrodynamic lubrication model is presented to investigate the transient process. In the model, the average Reynolds equation is adopted with considering the influences of surface deformation and starting temperature. Then the oil film and friction loss of the system and the journal center trajectory during engines starting up are analyzed. The results at different starting temperatures show that the asperity contact under the hot start-up condition is more serious. However, during the engine run-up and transition to idling phases, more viscous friction loss is generated under the cold start-up condition.