Patent ID: 9134194
Filing Date: 2015-09-15
Classification: B60C,G01L

Abstract:
1. A tire pressure decrease detection apparatus comprising: rotation speed information detection means for regularly detecting rotation speed information of tires of wheels of a vehicle, rotation acceleration information calculation means for calculating rotation acceleration information of the tires from the rotation speed information obtained by the rotation speed information detection means, resonance frequency estimate means for time-series estimating a torsional resonance frequency of the rotation acceleration information from the rotation acceleration information obtained by the rotation acceleration information detection means, correlation calculation means for, regarding front and rear wheels, respectively calculating wheel acceleration differences between left and right wheels based on the rotation acceleration information calculated by the rotation acceleration information calculation means, and calculating a time series correlation of the wheel acceleration differences of the front and rear wheels using the calculated wheel acceleration differences between the left and right wheels, and judgment means for judging a decrease in pressure of the tires based on the estimated torsional resonance frequency, wherein in a case where the time series correlation calculated by the correlation calculation means exceeds a predetermined threshold value, the resonance frequency estimate means takes 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.