Application of Micro-Perforated Panel in Automotive Vehicle Noise Refinement 2020-01-5078

To meet the regulatory requirements and improve passenger comfort inside the automotive vehicles, there is a need to reduce the interior noise levels. Generally, several components contribute to the interior noise rise in vehicles. The noise from the components can be reduced by directly working on the source or with passive methods. This paper focuses on the passive noise reduction methods. The passive method involves the usage of porous or fibrous sound-absorbing materials to absorb sound energy. The acoustic performance of these materials degrades because of heat, oil, and aging. In this paper, the application of acoustic material named micro-perforated panel (MPP) in an innovative way for sound absorption purposes is presented. These panels generally contain circular or slit-shaped perforations. The perforation sizes are generally in the submillimeter range. These panels are made with aluminum or steel, and hence these can be used in high temperatures and fire-resistant applications. This panel, when placed in front of a rigid wall with some backing cavity depth, forms an MPP absorber. The sound absorption coefficient (SAC) of an MPP absorber is validated in an impedance tube for various backing cavity depths. The study of the effect of sound incidence angle, sidewall material, and backing cavity partitioning on the sound absorption performance is carried out in an enclosure. The comparison of the absorber performance with polyurethane foam (PUF) is also shown. Later the MPP absorber is used for the noise reduction of a heating, ventilation, and air conditioning (HVAC) blower and for the development of a silencer for the air compressor noise reduction.