Vibration Performance Study Of Powertrain Mount System Based On Powertrain-body Coupling Model

Design and Research of powertrain mounting system has gone through a long process of development,from the initial design based on pure experience to the combination of computer simulation technology and theoretical system,its optimization methods and theoretical system has improved steadily.Currently,for the design and optimization of powertrain mounting systems,the traditional methods based on grounded 6-DOF rigid body model has been very mature,but the methods based on powertrain-body coupling model has a great space to explore.the traditional 6-DOF model ignored the coupling of each subsystems,so it can't accurately express its modal and kinematic coupling conditions while mounting on a vehicle.a model containing all subsystems can do a better job to obtian more reasonable mounting position,installation angle and stiffness parameters,thus design a more reasonable mounting system to reduce vehicle vibration and noise.This article will construct a powertrain-body coupling model including body and unsprung mass to complete the design of powertrain mounting system.main work are showing below:Firstly,the theoretical modeling process of 13-DOF powertrain-body coupling model has been derived in details,and constructed both in Matlab and Adams.then proved its correctness through a mode cross-comparison among two simulation results and modal test.Secondly,the concept of generalized decoupling rate has been proposed for the multiple DOF model to describe the energy decoupling between powertrain and body,body and wheels.Thirdly,the powertrain mount system's vibration performance has been Evaluated with idle shake analysis,key-off/on shake analysis and road excitation shake analysis.The detailed description of the three conditions and the theoretical calculation process of powertrain mounting system forced vibration are also given.Finally,a MPV's powertrain mount system has been analyzed and optimized with NSGA-?.Evaluated the optimization schemes with three conditions mentioned above to find out a best scheme which decoupling rate and vibration performance are both improved.the experimental results show that the noise performance of the car has been improved significantly after optimization.