Abstract
Sound Quality (SQ) finds it importance in gasoline engine since their noise levels are already low and the parameter that creates an impression on customers is its SQ. It is evident from the literature that there are limited researches exploring the SQ of gasoline engines. In present work a SQ index i.e. Pleasantness is formulated for gasoline engines that power the Indian passenger cars by identifying the relevant SQ metric. This is an extension of the work carried out on diesel powertrains previously [5]. Audio signals are recorded of engines on test bed. Jury evaluation of these signals is carried out to get the subjective ratings. Further this data is correlated with objective data to arrive at the psychoacoustic parameters that influence the subjective perception. 12 gasoline engines with the capacity of 1.0L – 1.6L with 3 - 4 cylinder are considered in the analysis and around 50 people were part of jury evaluation. All these engines have the SPL within 2dB range, hence the effect of SPL was nullified. The formulated pleasantness index is used to rate the gasoline engines which can give a single value to assess its SQ. It is found that the loudness and modulation metrics i.e. roughness and fluctuation strength, have the greater influence on subjective perception. The outcome of this work is an equation using which subjective responses can be predicted bypassing the actual time consuming jury evaluation.