Analysis And Optimization Of Vibration Isolation Performance Of A SUV Powertrain Mounting System

As one of the commonly used vehicles,NVH performance is a key indicator to evaluate the ride comfort and handling stability of the car,and the design of the powertrain suspension system has a great impact on the performance of the car NVH,in order to obtain good vibration isolation effect and thus improve the NVH performance of the car.How to design the suspension system is very important for the development of the car.In this paper,a certain model is taken as the research object,and the suspension system is optimized to improve its vibration isolation performance.The suspension system is mainly studied from the following aspects:Firstly,the research on vibration isolation performance at home and abroad is summarized.The types of suspension components and the roles of different layouts are clarified,and the excitation force formulas of single cylinder and four cylinder engine are analyzed in detail.Based on the vibration isolation theory,it is found that the natural frequency of the mounting system should be less than One-half of the root number the excitation frequency,so that the mounting system will not resonate with the excitation frequency.Secondly,the physical parameters of the engine are measured.The simulation model of the six degrees of freedom of the suspension system is established in ADAMS according to the parameters.The mathematical differential equation of the suspension system is established in MATLAB by Lagrange equation to verify the correctness of the simulation model.Then the inherent characteristics and decoupling rate of the suspension system and the dynamic characteristics under three operating conditions are analyzed.The analysis results show that the inherent characteristics of the suspension system are unreasonable,and there are serious coupling phenomena in several main vibration directions.The vibration generated under idle condition is the strongest.Therefore,the isolation performance of the suspension system is poor,and the optimal design of the suspension system is needed.Finally,under the premise that the decoupling rate is the target,the suspension stiffness is the design variable,and the natural frequency,decoupling rate and suspension stiffness of the system are the constraints,the influence degree of the design variable on the objective function is analyzed by sensitivity.Based on the multi-objective optimization method of ISIGHT integrated ADAMS software,the optimization of the suspension system is realized by adjusting the weight of the design variables.Comparing the suspension system before and after optimization,the optimization results show that the vibration isolation performance of the suspension system is improved,and the effectiveness of the optimization results is verified.