A method of measuring the powertrain noise for the indoor prediction of pass-by noise

Abstract This paper proposes a method of measuring the powertrain noise, which enables for the indoor prediction of the sound pressure level (SPL) of pass-by noise in an early stage of vehicle development phase. The proposed method is implemented in two steps. Firstly, the indoor tyre/roller noise is obtained by the indoor coast-by experiment based on the proposed single coast-by approach. Secondly, the powertrain noise is computed by subtracting the tyre/roller noise from the total vehicle noise. Then the powertrain noise is synthesized with the outdoor tyre/road noise energetically to predict the level of pass-by noise, with the purpose of reducing the influence caused by the difference between indoor and outdoor tyre/road noise. The proposed method is validated by experimental comparisons with the existing methods, shielding method and slick-tyre experiment method, respectively. The results show that the proposed method not only produces better prediction accuracy than the existing ones, but also has the ability to predict the pass-by noise SPL for a realistic case in an evaluation time of less than one hour.