Optimization of Oil Bores on Connecting Rod Small End to Prevent Bushing Failures at Maximum Speed

Abstract The bushing of connecting rod small end is one of the most prone components to failure in diesel engines. According to the previous study, the oil flowrate and storage of small-end bearing with splash lubrication are both minimal at maximum speed. Thus, the optimization of oil bores was performed using a model based on smooth particle hydrodynamics. By adjusting the angle between the axes of two oil bores to 90 deg, the oil flowrate and storage increase from 0.036 mL/s and 0.04 mL to 0.094 mL/s and 0.045 mL, respectively. A semicolumn baffle above the oil bore away from the piston cooling nozzle further increases them to 3.564 mL/s and 0.8 mL. The optimization greatly enhances the cooling intensity and oil supply stability of small-end bearing, conducing to prevent bushing failures.