Honda Motor Co., Ltd.
ROTATIONAL SPEED DETECTING DEVICE

Abstract:

A rotational speed detecting device that detects an engine rotational speed includes: a frequency estimation unit for estimating a frequency of vehicle interior sound as an estimated frequency based on a period of the vehicle interior sound detected by a microphone; an analysis frequency band setting unit for setting an analysis frequency band based on the estimated frequency; a frequency detection unit for performing spectrum analysis of the vehicle interior sound by discrete Fourier transform in the analysis frequency band and detecting the frequency of the vehicle interior sound as a detection frequency; and a rotational speed calculation unit for calculating an engine rotational speed based on the detection frequency.