Study On Vibration And Noise Control Of Electric Drive Air Conditioning System Of Electric Vehicle

With the rapid development of China's automobile industry,NVH performance has become an important indicator of vehicle comfort and technical strength.Whether a car can win the favor of the market,NVH performance has become a measurement standard.Electric vehicle is an important direction in the development of China's automobile industry in recent years,the loss of engine power makes the air conditioning system need to adopt electric compressor,at the same time because of a lack of the engine noise masking effect,the NVH problem in the air conditioning system of pure electric vehicles is particularly prominent.In this paper,the electric drive air conditioning system of an electric vehicle is taken as the research object to study its performance control of vibration and noise.The followsings are the main research contents:(1)On the electric drive air conditioning system with the electric drive compressor as the noise and vibration source,the inside noise testing and the vibration isolation performance testing are carried out on the right mount with the two-stage vibration isolation mechanism.On this basis,the contribution of inside noise was tested and analyzed,and the right suspension and air conditioning pipeline paths were determined as the two main structural transmission paths of inside noise.(2)Through the derivation of the expression of the force transmissibility of the single and double stage vibration isolation system,the reason why the double stage vibration isolation system has better performance than the single stage vibration isolation system in medium and high frequency is analyzed.Then,based on MATLAB,the mechanical model of the 12-degree-of-freedom two-stage isolation mount system of electric drive air conditioning is established and the natural frequency and modal energy decoupling rate of the system is calculated.(3)On the basis of multi-body dynamics theory,the dynamics model of two-stage isolation mount system of electric drive air conditioning was established based on ADAMS and simulated.The correctness of the simulation model was verified by comparing and analyzing the calculated results with MATLAB.Taking the stiffness of each mounting and bushing element as the design variable and the energy decoupling rate of the system as the optimization goal,the parametric optimization design of the system was carried out based on ADAMS to improve the vibration isolation performance of the system.(4)The effectiveness of ADAMS simulation optimization scheme is verified by experiments.Based on the generating mechanism of the air conditioning pipeline pulsation noise,an engineering optimization scheme was adopted to control the air conditioning pipeline transmission path,and the effectiveness of the optimization scheme was verified by experiments.