Patent ID: 6061642
Filing Date: 2000-05-09
Classification: B60C,B60T,G01P

Abstract:
A tire pressure drop detecting device for detecting drops in air pressure in a tires mounted on a vehicle, the tires including a driving tire and a following tire, the vehicle having a rotational velocity detector which detects, and provides an output indicative of the rotational velocities of the mounted tires, comprising:a slip factor calculating device, includingan initial correction factor calculating device havingmeans for accepting the output of said rotational velocity detector in a case where the vehicle is linearly coasting, andmeans for finding an initial correction factor for eliminating an effect of a relative difference in effective rolling radius depending on an initial difference among the mounted tires, on the rotational velocities, based on the accepted output of the rotational velocity detector,rotational velocity correcting means for correcting the accepted output of the rotational velocity detector, using the initial correction factor found by the initial correction factor calculating device, to determine corrected rotational velocities of the tires, andmeans for calculating a slip factor of the driving tire based on the corrected rotational velocities of the driving tire and the following tire;lateral acceleration determining means for determining a lateral acceleration exerted on the vehicle based on the corrected rotational velocities of the tires;substituting means for substituting the corrected rotational velocities of the tires in a predetermined expression, to determine an initial judged value;judged value correcting means for correcting the determined initial judged value based on the calculated slip factor and the determined lateral acceleration, to obtain a corrected judged value; andmeans for detecting a drop in air pressure in one of the tires based on the corrected judged value.