Transfer and Perception of Automotive Transmission Rattle 2015-01-1124

In order to improve the acoustic comfort inside passenger cars in terms of transmission noise, a special method has been developed. For a structured and comprehensive analysis of the transmission noise, the generation and transfer mechanisms are divided into four separate but nevertheless connected parts. Although simulation and components tests are used to analyze vibration excitation which may cause rattle and the mechanisms causing rattle in detail [1, 2], they are not the main part of the analysis. The focus of this study is on the transfer of automotive transmission rattle and the passengers' perception. The noise characteristics, which can be specified using conventional analysis methods as well as assessments by test persons, are important for the transfer path of the disturbing noise. By combining different methods of transfer path analysis (TPA), direct airborne-sound transmission is identified as a significant transfer path of the rattling noise. Based on assessments by test persons, which in turn are based on measurements with identical excitation of rattling noise, vehicle-specific differences in transfer are pointed out on the one hand. On the other, objective parameters to specify the transmission rattling noise independent of the vehicle are identified. Based on the presented analyses, the acoustic comfort in terms of transmission rattling noise can already be optimized during the development phase without affecting the efficiency of the full vehicle.