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During the pure electric vehicle high speed cruise driving condition, the unsteady air flow in the chassis cavity is susceptible to self-sustaining oscillations phenomenon. And the aerodynamic oscillation excitation could be coupled with the cabin interior acoustic mode through the body pressure relief vent, the low frequency booming noise may occur and seriously reduces the driving comfort. This paper systematically introduces the characteristics identification and the troubleshooting process of the low frequency aerodynamic noise case. Firstly, combined with the characteristics of the subjective jury evaluation and objective measurement, the acoustic wind tunnel test restores the cabin booming phenomenon. The specific test procedure is proposed to separate the noise excitation source.

With the continuous improvement of vehicle air leakage performance, an aural discomfort phenomenon had been occurred at the instant of vehicle door closing. There are many studies on door closing sound quality in past 20 years, but there is little publications on the study of the aural discomfort due to a transient high air pressure fluctuations. In this paper, the relationships of passenger’s aural discomfort produced by interior air pressure fluctuations are systematically studied. The ratio of door surface area to passenger compartment volume and other related parameters such as the cross-sectional area of a vehicle, the air extractor size, and the vehicle body air leakage under positive pressure are also studied through CAE analysis and verified through a large number of objective measurements and subjective vehicle evaluation.

An objective evaluation of sound quality is a technical bridge connecting sound pressure level (SPL) and human auditory sensation. In this paper, an algorithm is proposed for calculating objective evaluation parameters of sound quality (including loudness, sharpness and articulation index), considering acoustic characteristics of human external ear, middle ear and inner ear to reflect auditory sensation. A sound quality simulation (SQS) module is coded according to the algorithm. The module is used for evaluating sound quality of road noise from an SUV in three steps. Firstly, interior noise is predicted by integrating finite-element method (FEM), hybrid FE-SEA method, and statistical energy analysis (SEA) for low frequency (20~315 Hz), medium frequency (315~500 Hz), and high frequency (>500 Hz) in 1/3 octave band, respectively. The predicted interior noise SPLs are compared with the measured results, with deviations less than 3dB in average.