Thermo-Hydrodynamic (THD) Analysis of Oil Film Lubrication in the Connecting-Rod Big End Bearing

This paper presents the theory and temperature calculation of the connecting-rod big end bearing in the experimental device. Using the numberical method, Reynolds equation solution model for the hydrodynamic bearing, and Reynolds boundary conditions for the erosion phenomenon and oil film flow interruption, the research can calculate the pressure of the bearing. On that basis along with using the energy equation, we can build the temperature calculation model of the oil film. The research carries out the temperature differences of the connectingrod big end bearing oil film at different speeds. Also, it showes that the oil film temperature corresponds with the load on the connecting-rod. At the positon 0 o of the connecting-rod, the oil film temperature reaches the maximum value at the angle 360o of the crankshaft, which is where the explosion happens. At the opposite position, which is the 180o angle of the connecting-rod, the oil film temperature reaches the smallest value when the explosion happens because the oil film thickness is the biggest and the pressure is the smallest. At different positions of the connectingrod, the temperature range decreases from the position 0 o of the bearing to the position 180o and increases gradually from the position 180 o of the bearing to the position 360o . The temperature increases a lot during the first working cycles, and after that when the bearing operates stably, the oil film temperature will increase slightly along with the working time of the bearing