Design and experimental validation of a sound source model for engine of vehicles

Community noise regulations put stringent requirements on the exterior noise emission of vehicles. Noise from engines and tyres is the main contribution to noise pollution caused by traffic. It is imperative that automotive manufactures invest a lot of effort and money to improve the vibro-acoustics performance of their products. The enhancement effort may be very difficult and time-consuming if one relies only on trial and error´ method without prior knowledge about the sources itself. The implementation of sound source models is much faster than the trial and error´ methods. The purpose of this paper is to develop simple source models for engine noise using a mock-up panel of loudspeakers set up following the substituted monopole technique. The number and quantification of the sub-source factors is established here by the different cases under study. The real-life experience of listening to this sound is assessed by the implementation of DIN 45631/ISO 532B Loudness representation and the evaluation of the related sound quality, together with the annoyance level, are determined in a quick and economical manner.