Acoustic-Vibratory Characteristics of SF480 Diesel Engine Block

The sound radiation and vibration characteristics of the diesel engine block are studied in this paper with Finite Element Method (FEM) and Boundary Element method (BEM). First, the theoretical method to determine the vibratory and acoustic characteristics of the engine block is discussed. Secondly, based on the significance of its structural features, a 3D solid FEmodel of the engine block in software ANSYS was adopted to determine the dynamic characteristics including the natural frequencies and corresponding modal shapes. Meanwhile, the modal experiment is performed with impulse excitation method to verify the theoretical modal parameters. The frequency response functions from excitation point to the surface of noise radiation of the engine block are obtained by using the modal analysis technique and the dynamic characteristics. Then BEM is adopted to obtain the noise radiation property. The method proposed above was applied to the block of an actual dieselengine-SF480 four cylinders engine. The presented techniques are capable to investigate a low noise engine block structure.