Abstract
Abstract
This study investigates the influence of acoustic metric selection on vehicle sound power level estimation and the resulting noise emission curves derived from Controlled Pass-By (CPB) tests. Measurements were performed on seven light-duty vehicles with diesel, gasoline, hybrid-electric, and LPG powertrains over 30–90 km/h. Sound power levels were estimated using the maximum A-weighted sound pressure level (
L
AFmax
) and sound exposure level (
SEL
) related metrics through backward sound propagation. An average sound power level approach, based on instantaneous sound power within a 15 m reference space, was also proposed. Vehicle Noise Specific Power (VNSP) regression derived noise emission curves. Curves obtained from
L
AFmax
and the proposed approach agreed within 1 dB(A), whereas
SEL
-based metrics showed greater sensitivity to background noise at low speeds and integration window effects at higher speeds. The proposed approach provides a robust characterization of vehicle noise emissions and supports extending CPB-based methodologies to non-steady operating conditions.