Research On Dynamic Characteristics And Radiated Noise Of The Engine Oil Pan

The engine is the main noise source of the vehicle,while the radiation noise created by the oil pan and other thin-walled parts which have being excited accounted for about 25% of the machine noise.Therefore,reducing the oil pan and other thin-walled parts of the noise is of great significance for the whole engine noise reduction.In this paper,EQ4 H engine oil pan is the object of research,based on the combination of finite element method and boundary element method,the vibration and noise radiation of the oil pan are calculated and predicted.Based on the analysis results,the oil pan is optimized and redesigned,by comparing the vibration and noise performance of the oil pan before and after optimization,the effectiveness of the optimized design is verified.This paper contains four parts:1.Modal analysis and experimental verification of the oil pan.The modal analysis of the oil pan and the oil pan with lubricants is carried out,including the experimental modal analysis and the finite element calculation modal analysis,and then experimental and calculation modal results were compared,including the modal frequencies and modal modes,are used to verify the correctness of the finite element model.2.Frequency response analysis of oil pan.The vibration acceleration of the oil pan connection bolt was measured on the engine bench,as the oil pan input excitations of frequency response analysis,the frequency response analysis of the oil pan was calculated,and the acceleration response of the oil pan was obtained.3.Radiation noise analysis of the oil pan.The boundary element model of the oil pan was established,and the acceleration response of the oil pan was calculated as the boundary condition.,the radiated noise of the oil pan was calculated by the boundary element method.4.Optimization of the oil pan and the comparison of vibration and noise performance between the oil pan before and after optimization.Based on the results of frequency response and radiation field analysis,the oil pan is optimized by the method of topography optimization,and the effectiveness of the optimization design is verified by comparing the vibration and noise performances between the oil pan before and after optimization.