Acoustic simulation for evaluating loudspeaker location for pedestrian warning systems in EV/HEV

This paper presents results of a study aiming at establishing a simulation approach to predict the sound field around a passenger car generated by a loudspeaker mounted below the engine compartment. The activities were conducted in the context of a Pedestrian Warning System Development Program at Audi AG. A first requirement is the characterization of the loudspeaker as an acoustic source. Based on a combination of measurement and simulation of the loudspeaker in laboratory conditions, three different source models are developed. These source models are validated experimentally and subsequently integrated into a proper acoustic model to predict the noise radiated around the vehicle. Two different acoustic models are built: the first is based on the Acoustic Finite Element Method, the second on a Ray Tracing approach. Results from both simulation methods are compared to measured data and discussed.