The sound generated in the passenger compartment of an automobile is an essential criterion of driving comfort. In this paper an analytical method is presented for getting further information on the sound generation mechanism of abnormal exhaust noise. There was a serious problem with the muffler system of a 2-litre engined car. At first acoustical and modal analytical investigations are described, as well as some gas dynamical calculation. The paper describes the sound generation mechanism at gas dynamical stimulation. Possibilities of reducing the sound levels are shown and the problems of the supplementary detuning of the exhaust system are described. In the last part a new method to find the best position of the find the best position of the mufflers in a 3-muffler-exhaust system is presented. (A)
Samenvatting