Analysis Of Interior Noise Of Pure Electric Vehicle Under Power Train Excitation

Vehicle NVH performance is an important index to evaluate vehicle comfort.In this paper,a domestic pure electric vehicle as the research object,through the vehicle vibration noise test,analysis of the power train vibration and noise excitation on the impact of the interior noise.The LMS vibration and noise acquisition system was used to conduct 0-80 Km/h acceleration test of the vehicle,and the "source-path-receiver" analysis model was established.The vibration acceleration sensor and sound pressure sensor were arranged based on the vibration and noise excitation points of the pure electric vehicle power train,and the sound pressure sensor was arranged with the driver’s right ear as the output response point.The time domain data signals of vibration acceleration and noise sound pressure under acceleration conditions were collected as analysis samples for order analysis and partial coherence analysis to identify the source of internal noise and power train vibration noise.Based on the theory of order analysis,combined with the mechanism of vibration and noise generated by each part of the power train of pure electric vehicle,through the method of theoretical calculation analysis and test,the main order vibration noise excitation sources generated by the power train were identified,and the peak frequency of order vibration noise excitation was determined.The research shows that when the speed of pure electric vehicle is below 80Km/h,the impact of power train vibration noise on the interior noise is mainly within the frequency range of 500 Hz ～ 5000 Hz.The peak frequency of power train vibration noise is compared with the interior noise frequency.It is found that the peak frequency of the order vibration noise produced by the power train has a peak value under the corresponding frequency in the car.A multi-input single-output system model was established under the theory of partial coherence,the partial coherence function of input excitation to output response was calculated,and the contribution degree of vibration noise to the interior noise at each peak frequency was analyzed.The results show that the 24 order and 48 order vibration excitation generated by the motor are the main structural noise sources in the car,the 24 order electromagnetic noise generated by the motor and the 15 order gear meshing noise of the reducer are the main air noise sources in the car.In this paper,according to the structural characteristics and vibration and noise characteristics of the pure electric vehicle power train,the method of combining order analysis and partial coherence analysis is used to accurately identify the vibration and noise sources of the power train,as well as the impact of the vibration and noise excitation of the power train on the internal noise,which is suitable for the identification of the power train noise source and the contribution analysis of the internal noise source of the pure electric vehicle.It has engineering application value.