The usability of modern measuring and simulation techniques for psychoacoustical evaluation of combustion-engine noise was investigated. Assuming a linear time invariant (LTI) system, the sound generation process was divided into a sequence of filters that are applied to a source signal. The first transfer function of interest was the mobility of the structure. It was measured by a laser vibrometer, whereby the structure was excited by a shaker connected to a force transducer. Using these results, the second transfer function, i.e., the sound radiation of the engine into the free held was calculated by BEM. Although a very simplified model was used for this first step, comparison of computational results with microphone measurements showed good agreement. Finally, the car-engine sound was auralised. Recorded cylinder-pressure time histories were used as excitation signals and convolved with the entire impulse response. The synthesised sound was quite realistic. The final goal of the ongoing work is a complete simulation of car-interior sound, leading to shorter product development cycles. [References: 7]
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