Research On Key Technology Of NVH For Powertrain Mounting System

Automotive NVH performancehas been an important factor,whichgreatly affects the customer decision to select the demandingvehicle.As the main source of vibration,the powertrain system has a great impact on ride comfort and NVH characteristics for modern vehicles.Predicting and optimizing the impact of powertrain system on the Vehicle NVH performanceby CAE in the development stage,can reduce development risks and shorten product development cycles.This paper firstly reviewsthe NVH researchhistorycorresponding to the powertrainsystem's development,the basic principle of the vibration noise of the powertrain system,and the design theory ofisolation.The key technology of NVH for powertrain mounting is divided into three part.They are suspension rubber analysis and optimizing,mount bracket nalysis and optimizing and related vehicle NVH test.The article will Expound and analyze the principle,implementation method and optimization method of key technology.The following is the three key technologies are briefly introduced in this paperSecondly,this paper construct thegeneral arrangement method of powertrainsystem,and the way to obtainpowertrainparameters by experiment.A model whichcontains the correct parameters of the powertrain system is proposedby Matlab software.The main factors that influence the vibration of powertrain system,i.e.the modal and decoupling rateare analyzed theoretically.Then the correlation coefficients of idle speed start-up condition are calculated.The performance of themount system of powertrain was improved by optimizing the parameters(i.e.stiffness of the mount,angel of installation and location of installation)of the mount system through commercialsoftware Isight.Furthermore,the CAE approaches of analyzing the mode and dynamic stiffnessof themount bracketsare studied.The main reasonswhichinfluence thevibration noiseof the mount bracketsare analyzed;then the mode and dynamic stiffnessare computed by CAE.As a result,the topological optimization of the mount bracketsis obtained through optimizing thestructure of mount bracket with not only meeting the performance requirementsbut also reducingthe weight of the mount brackets.After a topology optimization model not only can meet the performance requirements,can also reduce the weight.Finally,the related experimental methods and evaluation indexes of the powertrain suspension system are proposed.The experimental contents include vibration noise test?mode test and vibration isolation rate test.These experiments can help us not only findingproblems that are not appeared in the earlystage of the design process but also improving the accuracyof the CAE model.From the experimental results show: using the key technology in designing and manufacturing of suspended sample,harshness(NVH)of vehicles are well performance,which show the effectiveness of the key technologies and operability.