Patent ID: 9528899
Filing Date: 2016-12-27
CPC Classification: B60C,G01L

Claim Text:
1. A tire pressure decrease detection apparatus comprising: a rotation speed information detection mechanism configured to regularly detect rotation speed information of tires of wheels of a vehicle, a rotation acceleration information calculation mechanism configured to calculate rotation acceleration information of the tires from the rotation speed information obtained by the rotation speed information detection mechanism, a resonance frequency estimate mechanism configured to time-series estimate a torsional resonance frequency of the rotation acceleration information from the rotation acceleration information obtained by the rotation acceleration information detection mechanism, a correlation calculation mechanism configured to, regarding front and rear right wheels and front and rear left wheels, respectively calculate time series correlations of the rotation acceleration information calculated by the rotation acceleration information calculation mechanism, and a judgment mechanism configured to judge a decrease in pressure of the tires based on the estimated torsional resonance frequency, wherein in a case where the correlations calculated by the correlation calculation mechanism exceed predetermined threshold values, the resonance frequency estimate mechanism is configured to determine that a periodic noise from a road surface is generated in the vicinity of the torsional resonance frequency and stops estimating the torsional resonance frequency of the front and rear wheels of the side exceeding the threshold value.