Tribology and Characterization of Dynamically-Loaded Crankshaft Main Bearings with Surface Roughness

Crankshaft main bearings often operate in mixed lubrication due to the periodic impact of engine cylinder pressure. This study explores the tribology and dynamic response of crankshaft main bearing considering different surface roughness and engine dynamic load using a numerical model. The coupling effects of hydrodynamic force, engine dynamic load and unbalanced force are considered in the dynamic equation with the asperity contact and elastic deformation. The simulation results reveal that the effects of engine dynamic load and surface roughness on the dynamic behavior and lubrication characteristics, such as minimum oil film thickness, oil film pressure distribution, asperity contact friction and journal trajectory. In addition, the effects of operating speed and torque on the tribo-dynamic response of crankshaft are identified. The results of numerical spectrum analysis show that the operation condition influence asperity friction force greatly, which represents different lubrication condition of crankshaft. This research can provide a theoretical foundation for condition monitoring of vibration signals associated with crankshaft main bearing lubricity and asperity contact.