Abstract：To reduce the diesel engine＇s overall noise, an improved noise reduction design method for the engine block was proposed based on virtual prediction method. A multi-body dynamics model, which ineludes a flexible cylinder block, crankshaft-flywheel and rigid connect rod, piston, and bal-shafts, was set up to perform simulation. The simulation result predicted the forces acting on the engine during operation, such as bearing loads and piston side thrust loads. The FEM/BEM was used to predict the radiated noise of the engine block. The result agrees well with the test data. Finally, by redesigning the structure of original engine block, the radiated sound level was reduced by 1.74 dB （A） , the excitations transferred to oil pan and gear cover were decreased and the block weight was reduced by about 5 kg.
2008, Vol. 29 
