Airborne transfer path analysis for an e-compressor

The goal of this paper is to provide a method for airborne source description of the EC and to determine the airborne sound contribution at the driver's ear. The radiation of the EC was approximated by six acoustic monopoles emitting a volume acceleration. The characterization was conducted with the help of noise transfer functions (NTFs) and operational measurements in an anechoic chamber. Volume acceleration sources were used to measure the NTFs. The validation of the source identification was performed in a changed environment and a vehicle. The first results for the sound pressure predictions at the driver's ear showed good agreement to the reference measurements. However, in the high-frequency range, the prediction was partly deviating from the reference. To further improve the accuracy, an artificial EC was constructed to replace the volume sources for the NTF measurements. Thereby the predictions could be improved in the high-frequency range. These results are also validated in a changed environment.