Currently, research of sound quality of automobiles is mainly focused on the steady sound, and there are very few methods for transient sound quality evaluation. In addition, traditional FFT method is often adopted in sound signal processing, while the transient property of the acoustic signal has not been considered adequately. Automotive door closing sound is a transient impulse sound, and the quality of door closing sound can reflect the quality of vehicles. In this paper, first of all, the quality of door closing sound of some types of vehicles is evaluated using traditional evaluation parameters. Then, the wavelet transform method is used to analyze the sound signal of the door closing sound in time frequency domain. It is indicated that the traditional parameters such as loudness, sharpness, roughness, and so on can not sufficiently reflect the sound quality characteristics of transient sound, while the time-frequency analysis is a good complement for the sound quality evaluation. However, selection of the evaluation parameters remains a problem for further study.

The model of the RWD’s SUV for torsional vibration analysis is established, and the torsional vibration modes of the SUV are computed. The validity of the model and algorithm is proved by comparing the results with measured data. Subsequently, the model and algorithm are employed to study the sensibility of the driveline’s torsional modes to the clutch damper stiffness, transmission-shaft stiffness and axle shaft stiffness. Finally, the influence of the torsional stiffness of the driveline’s components, such as conventional clutch damper, transmission shaft and axle shaft, on the torsional vibration modes of the driveline is summarized. This work is of significance for target setting of driveline’s torsional vibration modes and the development of driveline’s NVH.

The vibration characteristics and the capability of sound insulation of multilayer panels are very important factors which dominate acoustic response in car cavity. A simplified car body model is made to investigate the effects of multilayer panels on interior sound levels. The relation between the acoustic response of the cavity and the damping treatment are achieved. Acoustic-structural sensitivity of car body damping treatment is evaluated synthetically. The damping treatment’ structure is optimized, and car interior sound level is improved.