Audible Noise Simulation – an Attempt to Predict Idling Rattle in Manual Transmissions

In the previous paper⁽¹⁾, the authors reported the calculation method they developed for predicting the idling rattle in manual transmissions. This method provides data that represent noise levels to which human ear is not sensitive by numerical values.

In the study described in this paper, the authors attempted to produce audible noise through a speaker by the following process: create time-series data of fluctuation in the angular acceleration obtained by the calculation (which is considered to correspond to rattle noise); create next-stage data by applying convolution of a transmission case's vibration transfer characteristics filter obtained by the experiment to the above-mentioned time-series data; convert the filtered data into a wave file; and then input the file to a personal computer to obtain audible sound as output. The audible noise thus produced provides a means of evaluating the level and nature of noise in the way humans naturally experience it. This paper reports the above-mentioned study as an effective approach to noise-reducing efforts made by engineers working on the development stages of new vehicles.