Patent ID: 6804623
Filing Date: 2004-10-12
Classification: B60C

Abstract:
A method for detecting decrease in tire air-pressure in which decrease in internal pressure of a tire is detected on the basis of rotational information obtained from tires attached to a vehicle, comprising the steps of:detecting and storing rotational information of the respective tires; calculating and storing a slip rate; calculating and storing a correction coefficient for correcting a difference in effective rolling radii owing to initial differences between right and left front tires, a correction coefficient for correcting a difference in effective rolling radii owing to initial differences between right and left rear tires and a correction coefficient for correcting a difference in effective rolling radii owing to initial differences between front tires and rear tires; comparing a first correction coefficient between front tires and rear tires obtained from rotational information which are gained from tires attached to the vehicle when performing cornering running other than freewheeling with a second correction coefficient between the front tires and the rear tires preliminarily obtained when at normal internal pressure; and judging simultaneous decompression of two wheel tires of both front wheels or simultaneous decompression of two wheel tires of both rear wheels on the basis of a relationship between a value obtained through comparison of the first and second correction coefficients and a specified threshold.