Low Noise Design of Cylinder Head Cover Based on Multi-objective Topography Optimization

In order to reduce the structural radiation noise of a diesel engine cylinder head cover, the finite element method (FEM) and boundary element method (BEM) were used for its virtual prediction and obtained the critical modal with dominant contribution to the structural radiation noise. Considering the static stiffness and several critical dynamic frequencies as Euclidean distance's multi-objective function, weighted compromise programming approach was applied to multi-objective topography optimization of the cylinder head cover. With the optimization result, the CAD model of the cover was redesigned taking manufacturing and assembling process into account. Finally, the radiation noise of the optimized cylinder head cover was analyzed under the same boundary conditions. The results show that the integral stiffness is improved, the critical frequencies avoid the original resonance frequency range that radiates noise most and the total acoustic power level has dropped by 3.5 dB (A).