Visual Effect of Engine Automatic Start Timing Indicator on Impression of Unexpected Engine Start Sound of Hybrid Vehicle

Abstract

In this study, we carried out subjective evaluation tests employing engine automatic start sounds of hybrid electric vehicle with idling reduction function. The result showed uneasiness feeling was increased by the engine automatic start sound. On the other hand, the negative feeling was actually reduced effectively by presenting a visual indicator notifying the engine start timing to the participants. The effect was equivalent to 2 dB reduction of the start sound SPL. Consequently, the rotational speed at the engine idling has a possibility to be changed more flexibility according to the electricity charging efficiency by using the visual indicator.