Experimental Study of the Acoustics of a Electric Refrigerant Scroll Compressor 2024-01-2924

In electrified vehicles, auxiliary units can be a dominant source of noise, one of which is the refrigerant scroll compressor. Compared to vehicles with combustion engines, e-vehicles re-quire larger refrigerant compressors, as the battery and the electric motors must be cooled in addition to the interior. The compressor causes the acoustic excitation of other refrigeration circuit components and the chassis via pressure pulsations and vibration transmission, as well as emitting airborne sound directly. Sound measurements have been performed in an anecho-ic chamber to investigate the influence of operating conditions on the acoustics of an electric scroll compressor. This paper investigates the influence of the operating conditions on com-pressor acoustics and shows that rotation speed is the main factor influencing compressor noise. The sound spectra of fluid, structure and airborne noise are dominated by speed-dependent, tonal components. Additionally the effect of varying pressure, superheat and filling quantity in the refrigeration circuit on the acoustic properties of the scroll compressor have been investigated. A comparison with acoustic measurements of the compressor installed in the vehicle shows which sounds are perceived by people both inside and outside the vehicle. The findings provide insights into the physical relationship between operating conditions and acoustic parameters and enable the development of suitable sound reduction measures.