Engine Vibration and Noise Reduction Using a Crank-Block System Model

A coupled engine-block and crankshaft model is developed and applied to predict the engine block vibration and radiated noise. Block surface vibration which is excited by combustion pulses and inertia loads is investigated as the source of radiated noise. The predicted response shows the dominant engine harmonics, resonant frequencies, global modes and local surfaces which participate to produce the radiated noise. A structural modification is evaluated which reduces the transmission of the loads through the bulkheads, and significant vibration and noise reduction is predicted.