Abstract:

With the continuous improvement of motor drive technology and aerodynamic technology， the trend of high-speed pure electric vehicles is becoming more and more obvious. At high speed， the peak value of low-frequency aerodynamic noise caused by chassis cavity may exceed 60 dB（A）， which seriously affects driving comfort. Taking the low-frequency noise problem of a pure electric vehicle under high-speed working conditions as a case， the investigation and analysis of low-frequency noise problems and the verification process of generation mechanism analysis are systematically expounded. Firstly， the type of high-speed driving excitation source is analyzed， and the excitation source separation test is carried out through the wind tunnel to lock the low-frequency noise as the type of aerodynamic noise. Secondly， the potential mechanism of low-frequency aerodynamic noise formation is inferred， and the test is designed to check and analyze the potential mechanism. It is determined that the vortex-acoustic coupling self-excited oscillation of the chassis cavity is the cause of low-frequency aerodynamic noise. Finally， the potential mechanism is verified by simulation analysis， semi-empirical formula calculation and real vehicle test， and the engineering scheme is designed to solve the problem. It has important engineering significance for the analysis， identification and solution of aerodynamic noise problems of pure electric vehicles at high-speed conditions.

Key words: electric vehicle, cavity, self-excited oscillation, coupling, aerodynamic noise