Research On Engine Mounting Design And Optimization Based On Cab Noise Control

With the development of domestic automobile industry in recent years,consumers and automobile companies pay more attention to the NVH performance.Considering that engine excitation is the largest source of excitation in the running vehicle and engine mounting can isolate engine excitation effectively,so,the engine mounting system is one of the major factors which influence the vehicle NVH performance.The traditional engine mount design focuses on controlling the vibration isolation performance of the spring element and improving the energy decoupling ratio of the suspension assembly while ignoring the energy transfer paths' characteristics involved in the mounting system.The high-energy vibration and noise transmission path analysis of the suspension system is combined to optimize the suspension-related parameters to effectively reduce the structural noise response in the cab caused by engine excitation.The main work is as follows:(1)Establishing a simulation model of the engine mount system and verify its accuracy.Simplifying the engine and body structure into a rigid structure to complete the simulation model which including an engine and a suspension system.Comparing with the experimental and simulation data of the engine mounting system rigid body modal to verify the accuracy of the model.(2)Identificating high energy transmission pathways through TPA.The power is synthesized by the frequency response function of the force and velocity of the suspension main and passive ends,Analysing vibration paths of suspensions based on power flow and identification of high energy transmission paths.Acquiring the force-sound transfer function from the passive side of the suspension point to the acoustic chamber of the cab through the test method,combining the passive side response and NTF to calculate the sound pressure response at the target point under the action of a single noise transmission path.(3)Optimization of mounting parameters combined with high energy path of engine suspension body.For the identified high-energy transmission path with the suspension involved,the three-dimensional stiffness of the suspension is adjusted.Based on this,the suspension stiffness and the elastic center point coordinates are optimized by the genetic algorithm.Suspended in decoupling performance has improved after the optimization.(4)The experimental verification of the optimized mounting performance was performed.The vibration of the suspension and the sound pressure in the cabin acoustic chamber were tested under various operating conditions to verify the improved performance of the rear mount vibration isolation.The research work in this paper has certain theoretical and engineering value to control the vibration of the body structure and improve the noise response of the cab.