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 decrease in air pressure of a tire attached to a vehicle, comprising:
- a rotation speed detection means for periodically detecting rotation speeds of tires of respective wheels of the vehicle;
a rotation wheel speed ratio calculation means for calculating, based on rotation speed information obtained by the rotation speed detection means, a rotation wheel speed ratio between front wheels and rear wheels of the vehicle with regard to a plurality of predetermined speed regions;
a wheel torque calculation means for calculating a wheel torque of the vehicle;
an initialization means for obtaining, with regard to the respective speed regions, a relation at a normal internal pressure between the wheel torque and the rotation 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, with regard to the respective speed regions, the rotation wheel speed ratio obtained by the rotation wheel speed ratio calculation means with the rotation 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 the storage means; and
a determination means for correcting the comparison result by the comparison means by a front-to-rear direction acceleration and for determining, based on the resultant corrected value, whether there is a tire having a decreased air pressure or not.
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Accused Products
Abstract
An apparatus for detecting a decrease in air pressure of a tire attached to a vehicle includes a rotation speed detection means for periodically detecting rotation speeds of tires of respective wheels of the vehicle; a rotation wheel speed ratio calculation means for calculating a rotation 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 rotation wheel speed ratio; a comparison means for comparing the rotation wheel speed ratio with the rotation wheel speed ratio at a normal internal pressure obtained from the wheel torque and the relation; and a determination means for correcting the comparison result by a front-to-rear direction acceleration and determining whether there is a tire having a decreased air pressure or not.
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Citations
21 Claims
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1. An apparatus for detecting a decrease in air pressure of a tire attached to a vehicle, comprising:
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a rotation speed detection means for periodically detecting rotation speeds of tires of respective wheels of the vehicle; a rotation wheel speed ratio calculation means for calculating, based on rotation speed information obtained by the rotation speed detection means, a rotation wheel speed ratio between front wheels and rear wheels of the vehicle with regard to a plurality of predetermined speed regions; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining, with regard to the respective speed regions, a relation at a normal internal pressure between the wheel torque and the rotation 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, with regard to the respective speed regions, the rotation wheel speed ratio obtained by the rotation wheel speed ratio calculation means with the rotation 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 the storage means; and a determination means for correcting the comparison result by the comparison means by a front-to-rear direction acceleration and for determining, based on the resultant corrected value, whether there is a tire having a decreased air pressure or not. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for detecting a decrease in air pressure of a tire attached to a vehicle, comprising:
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a processor configured to perform the following steps; a rotation speed detection step of periodically detecting rotation speeds of tires of respective wheels of the vehicle; a rotation wheel speed ratio calculation step of calculating, based on rotation speed information obtained in the rotation speed detection step, a rotation wheel speed ratio between front wheels and rear wheels of the vehicle with regard to a plurality of predetermined speed regions; a wheel torque calculation step of calculating a wheel torque of the vehicle; an initialization step of obtaining, with regard to the respective speed regions, a relation at a normal internal pressure between the wheel torque and the rotation wheel speed ratio between the front wheels and the rear wheels; a storage step of storing the relation obtained in the initialization step; a comparison step of comparing, with regard to the respective speed regions, the rotation wheel speed ratio with the rotation wheel speed ratio at a normal internal pressure obtained from the wheel torque and the stored relation; and a determination step for correcting the comparison result in the comparison step by a front-to-rear direction acceleration and for determining, based on the resultant corrected value, whether there is a tire having a decreased air pressure or not. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A computer program product for detecting a decrease in air pressure of a tire, the computer program product comprising a non-transitory computer-readable storage medium having computer-executable program code stored therein, the computer-executable program code causing, in order to detect a decrease in an air pressure of a tire attached to a vehicle, a computer to function as:
a rotation wheel speed ratio calculation means for calculating, based on rotation speed information obtained by a rotation speed detection means for periodically detecting rotation speeds of tires of respective wheels of the vehicle, a rotation wheel speed ratio between front wheels and rear wheels of the vehicle with regard to a plurality of predetermined 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 rotation wheel speed ratio between the front wheels and the rear wheels with regard to the respective speed regions;
a comparison means for comparing, with regard to the respective speed regions, the rotation wheel speed ratio obtained by the rotation wheel speed ratio calculation means with the rotation 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 determination means for correcting the comparison result by the comparison means by a front-to-rear direction acceleration and for determining, based on the resultant corrected value, whether there is a tire having a decreased air pressure or not.- View Dependent Claims (16, 17, 18, 19, 20, 21)
Specification