Analysis of Vibratory Response of Engine Block Coupled with Rotating Crankshaft and Its Radiated Noise

Abstract

Noise Control of the internal combustion engine in early design stage enjoins the analytical procedure to estimate the exciting forces, vibratory behavior of the engine block and the noise radiation properties. This paper presents a theoretical approach to predict the vibratory response of the engine block coupled with the rotating crankshaft considering the dynamic characteristics of the block, stiffness of the oil film and the main bearings, and exciting forces such as the gas force, inertia force, piston slap and so on. Engine noise radiated from the structure is estimated by use of the spatially averaged mean square velocity and the acoustic radiation efficiencies of the block surface. Numerical simulation offers the wave form of the vibration acceleration of the engine block and the estimated noise spectrum is compared with the measured one.