Fuel injection pump driven by the crankshaft gear via gear trains is considered one of the major noise sources of the internal combustion engine because it injects instantly the fuel fluid at high pressure and induces the impulsive vibration of the gear trains and pump structure. This paper presents the theoretical procedure to predict the vibratory response of the engine block coupled with the rotating crankshaft and gear train shafts which drives the fuel injection pump and valve system. Moreover the engine noise radiated from the engine block surface is evaluated using the spatially averaged mean squared velocity and acoustic radiation efficiencies of the engine block. This method is applied to estimate the effect of the backlash of the gear system and the fuel injection pressure onto the engine block vibration and radiated noise.
