Simulation of acceleration pass–by noise considering the acoustic radiation characteristics of a vehicle body

The principal noise sources of acceleration pass–by noise are engine and exhaust discharge noise in most cases. In this paper, to improve the prediction accuracy of engine noise and exhaust discharge noise, the acoustic radiation characteristics of the vehicle body are investigated in detail. The characteristic values representing the magnitude of sound insulation and the directivity due to the body are introduced to engine noise propagation and exhaust discharge noise propagation. Furthermore, additional sources such as exhaust surface noise (radiation noise from the surface of exhaust system) and tyre noise are also evaluated utilizing the sound intensity method for exhaust surface noise and the point–source models for tyre noise. Combining the vehicle acceleration performance simulation also available to the vehicle with automatic transmission and the prediction method outlined in this paper, the accuracy of the pass–by noise prediction is considerably improved for instantaneous change of noise levels as well as the peak levels.