Method and apparatus for detecting decrease in tire air-pressure, and selecting program for thresholds for judging decompression of tire

• US 20030034884A1
• Filed: 08/16/2002
• Published: 02/20/2003
• Est. Priority Date: 08/16/2001
• Status: Active Grant

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation), Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation), Sumitomo Rubber Industries Limited
• Inventors: Oshiro, Yuji
• Granted Patent: US 6,756,891 B2
• Time in Patent Office: Days
• US Class Current: 340/443
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00

Abstract

A method for detecting decrease in tire air-pressure for detecting decrease in internal pressure of a tire on the basis of rotational information obtained from tires attached to a vehicle. A threshold for judging decrease in air-pressure of following wheels is different from a threshold for judging decrease in air-pressure of driving wheels. Threshold for judging abnormalities in air-pressure are varied for judging abnormalities of tire air-pressures of following wheels and for judging abnormalities of tire air-pressure of driving wheels so that appropriate judgment of abnormalities in air-pressure can be performed.

Claims

1. A method for detecting decrease in tire air-pressure for detecting decrease in internal pressure of a tire on the basis of rotational information obtained from tires attached to a vehicle, wherein a threshold for judging decrease in air-pressure of following wheels is different from a threshold for judging decrease in air-pressure of driving wheels.

2. An apparatus for detecting decrease in tire air-pressure for detecting decrease in internal pressure of a tire on the basis of rotational information obtained from tires attached to a vehicle, comprising:

a rotational information detecting means for detecting rotational information of respective tires;

a steering angle detecting means for detecting a steering angle;

a memory means for storing the rotational information of the respective tires and the steering angle;

a straight-ahead drive judging means for judging, based on the steering angle, whether the vehicle is performing straight-ahead driving;

a turning radius calculating and processing means for calculating a turning radius on the basis of the rotational information of the tires;

a comparing and determining means for determining, on the basis of the turning radius as calculated by the turning radius calculating and processing means, whether the vehicle is performing straight-ahead driving or not in case it has been determined on the basis of the steering angle that the vehicle is performing straight-ahead driving;

a threshold selecting means for selecting a threshold for judging decrease in air-pressure on the basis of the determination of the comparing and determining means; and

a judged value calculating and processing means for calculating a judged value of decompression of air-pressure on the basis of the threshold.

3. The apparatus of claim 2, wherein the comparing and determining means judges whether tire air-pressure of the following wheels is abnormal or the air-pressure of the driving wheels is abnormal.

4. A selecting program for a threshold for judging decompression of a tire which is so arranged that, for selecting a threshold for judging decrease in tire air-pressure, a computer is made to function as a rotational information detecting means for detecting rotational information of respective tires, a steering angle detecting means for detecting a steering angle, a memory means for storing the rotational information of the respective tires and the steering angle, a straight-ahead drive judging means for judging, based on the steering angle, whether the vehicle is performing straight-ahead driving, a turning radius calculating and processing means for calculating a turning radius on the basis of the rotational information of the tires, a comparing and determining means for determining, on the basis of the turning radius as calculated by the turning radius calculating and processing means, whether the vehicle is performing straight-ahead driving or not in case it has been determined on the basis of the steering angle that the vehicle is performing straight-ahead driving, a threshold selecting means for selecting a threshold for judging decrease in air-pressure on the basis of the determination of the comparing and determining means, and a judged value calculating and processing means for calculating a judged value of decompression of air-pressure on the basis of the threshold.