Apparatus and method for detecting decrease in tire air pressure and program for detecting decrease in tire air pressure
First Claim
1. An apparatus for detecting a tire attached to a vehicle having a decreased air pressure, comprising:
- a rotation velocity detection means for periodically detecting rotation velocities of tires of the respective wheels of the vehicle;
a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information obtained from the rotation velocity detection means, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle;
a wheel torque calculation means for calculating a wheel torque of the vehicle;
an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels;
a storage means for storing the relation obtained by the initialization means;
a comparison means for comparing the rotating wheel speed ratio obtained by the rotating wheel speed ratio calculation means with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation stored in the storage means; and
a judgment means for judging whether a tire air pressure is decreased or not based on a comparison result by the comparison means.
1 Assignment
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Accused Products
Abstract
An apparatus includes a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels; a storage means for storing the relation obtained; a comparison means for comparing the rotating wheel speed ratio obtained by the rotating wheel speed ratio calculation means with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation; and a judgment means for judging whether a tire air pressure is decreased or not based on a comparison result.
16 Citations
24 Claims
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1. An apparatus for detecting a tire attached to a vehicle having a decreased air pressure, comprising:
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a rotation velocity detection means for periodically detecting rotation velocities of tires of the respective wheels of the vehicle; a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information obtained from the rotation velocity detection means, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels; a storage means for storing the relation obtained by the initialization means; a comparison means for comparing the rotating wheel speed ratio obtained by the rotating wheel speed ratio calculation means with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation stored in the storage means; and a judgment means for judging whether a tire air pressure is decreased or not based on a comparison result by the comparison means. - View Dependent Claims (2, 3, 4)
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5. An apparatus for detecting a tire attached to a vehicle having a decreased air pressure, comprising:
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a rotation velocity detection means for periodically detecting rotation velocities of tires of the respective wheels of the vehicle; a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information obtained from the rotation velocity detection means, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle for a predetermined plurality of speed regions; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels for the respective speed regions; a storage means for storing the relation obtained by the initialization means; a comparison means for comparing, for the respective speed regions, the rotating wheel speed ratio obtained by the rotating wheel speed ratio calculation means with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation stored by in storage means; and a judgment means for judging whether a tire air pressure is decreased or not based on a comparison result by the comparison means. - View Dependent Claims (6, 7, 8)
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9. A method for detecting a tire attached to a vehicle having a decreased air pressure, comprising:
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a rotation velocity detection step of periodically detecting rotation velocities of tires of the respective wheels of the vehicle; a rotating wheel speed ratio calculation step of calculating, based on rotation velocity information obtained in the rotation velocity detection step, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle; a wheel torque calculation step of calculating a wheel torque of the vehicle; an initialization step of obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels; a storage step of storing the relation calculated in the initialization step; a comparison step of comparing the rotating wheel speed ratio with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque and the stored relation; and a judgment step of judging whether a tire air pressure is decreased or not based on a comparison result obtained in the comparison step. - View Dependent Claims (10, 11, 12)
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13. A method for detecting a tire attached to a vehicle having a decreased air pressure, comprising:
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a rotation velocity detection step of periodically detecting rotation velocities of tires of the respective wheels of the vehicle; a rotating wheel speed ratio calculation step of calculating, based on rotation velocity information obtained in the rotation velocity detection step, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle for a predetermined plurality of speed regions; a wheel torque calculation step of calculating a wheel torque of the vehicle; an initialization step of obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels for the respective speed regions; a storage step of storing the relation obtained in the initialization step; a comparison step of comparing, for the respective speed regions, the rotating wheel speed ratio with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque and the stored relation; and a judgment step of judging whether a tire air pressure is decreased or not based on a comparison result in the comparison step. - View Dependent Claims (14, 15, 16)
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17. A program for causing, in order to detect a decrease in an air pressure of a tire attached to a vehicle, a computer to function as;
- a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information obtained from a rotation velocity detection means for periodically detecting rotation velocities of tires of the respective wheels of the vehicle, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle;
a wheel torque calculation means for calculating a wheel torque of the vehicle;
an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels;
a comparison means for comparing the rotating wheel speed ratio obtained by the rotating wheel speed ratio calculation means with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation obtained by the initialization means; and
a judgment means for judging whether a tire air pressure is decreased or not based on a comparison result by the comparison means. - View Dependent Claims (18, 19, 20)
- a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information obtained from a rotation velocity detection means for periodically detecting rotation velocities of tires of the respective wheels of the vehicle, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle;
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21. A program for causing, in order to detect a decrease in an air pressure of a tire attached to a vehicle, a computer to function as;
- a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information obtained from a rotation velocity detection means for periodically detecting rotation velocities of tires of the respective wheels of the vehicle, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle for a predetermined plurality of speed regions;
a wheel torque calculation means for calculating a wheel torque of the vehicle;
an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotating wheel speed ratio between the front wheels and the rear wheels for the respective speed regions;
a comparison means for comparing, for the respective speed regions, the rotating wheel speed ratio obtained by the rotating wheel speed ratio calculation means with the rotating wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation obtained by the initialization means; and
a judgment means for judging whether a tire air pressure is decreased or not based on a comparison result by the comparison means. - View Dependent Claims (22, 23, 24)
- a rotating wheel speed ratio calculation means for calculating, based on rotation velocity information obtained from a rotation velocity detection means for periodically detecting rotation velocities of tires of the respective wheels of the vehicle, a rotating wheel speed ratio between front wheels and rear wheels of the vehicle for a predetermined plurality of speed regions;
Specification