Apparatus for estimating tire air pressure

摘要

A signal processor (6) comprises wheel speed-detecting means (100) for detecting a wheel speed signal including vibrational components of a tire, extraction means (120, 130) for extracting a resonant frequency of the vibrational components of the tire or a tire spring constant based on the wheel speed signals, air pressure-estimating means (150) for estimating a tire air pressure based on the resonant frequency or the tire spring constant, and determining means (150) for determining whether the estimated tire air pressure is abnormal or not by comparing with a determination value. Further, correcting means (corrects at least one of the determination value, the estimated tire air pressure, the resonant frequency and the tire spring constant in response to a tire temperature. A temperature-sensing device is mounted inside the signal processor to detect a temperature associated with the tire temperature. <IMAGE>