Detecting tire decompression based on wheel speed

• US 7,551,992 B2
• Filed: 11/01/2004
• Issued: 06/23/2009
• Est. Priority Date: 11/25/2003
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Kitano, Masashi
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Peche; Jorge O
• Application Number:
  US10/977,440
• Publication Number:
  US 20050113992A1
• Time in Patent Office: 1,695 Days
• Field of Search: 701/29, 116/34, 137223-224, 141/38, 200/61.22, 338/37, 340/442, 425/15, 731/462, D10/86
• US Class Current: 701/29
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00
• CPC Class Codes: Y10T 137/3584 Inflatable article [e.g., tire filling chuck and/or stem]
• CPC Class Codes: Y10T 137/36 With pressure-responsive pressure-control means

Abstract

A method for detecting decompression of tires based on the rotational speed of wheels mounted on a vehicle, comprising the steps of: detecting the rotational speed of each of the above-mentioned wheels, determining the speed against ground of the vehicle, calculating the speed information of a fixed wheel from the rotational speeds of said wheels, calculating the judgment value of the wheel position by comparing the speed information of the wheels with the speed against ground of the vehicle, comparing the judgment value of the wheel position with the basis value of the wheel position obtained by preliminarily comparing the speed against ground of the vehicle with the speed information of the wheels at prescribed inner pressure, and judging decompression of tires based on relation between the comparison value of the basis value with the judgment value and a fixed threshold. A region of judging decompression of tires can be broadened and the accuracy of reduced pressure judgment can be improved.

Claims

1. A method for detecting decompression of tires based on rotational speeds of wheels mounted on a vehicle, comprising the steps of:

detecting a rotational speed of each of said wheels;

determining a ground speed of said vehicle;

calculating (1) speed information obtained from an average wheel speed of a front left wheel and a rear left wheel and (2) speed information obtained from an average speed of a front right wheel and a rear right wheel, from the rotational speeds of said wheels;

memorizing the rotational speed of each of the wheels and the speed informations;

calculating (1) a judgment value for the left side wheels by comparing the speed information obtained from the average wheel speed of the front left wheel and the rear left wheel with the ground speed of the vehicle and (2) a judgment value for the right side wheels by comparing the speed information obtained from the average wheel speed of the front right wheel and the rear right wheel with the ground speed of the vehicle;

comparing the judgment value for the left side wheels with a basis value for the left side wheels obtained by comparing a speed information obtained from an average speed of the front left wheel and the rear left wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for the left side wheels;

comparing the judgment value for the right side wheels with a basis value for the right side wheels obtained by comparing a speed information obtained from an average speed of the front right wheel and the rear right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for the right side wheels; and

judging decompression of tires by comparing the comparison values with a fixed threshold.

2. The method for detecting decompression of tires of claim 1, wherein the ground speed of said vehicle is determined by signals demodulated from received GPS radio waves and time.

3. A detection device for detecting decompression of tires based on rotational speeds of wheels mounted on a vehicle, comprising:

a wheel rotational speed-detecting means for detecting a rotational speed of each of said wheels;

a ground speed calculating means for determining a ground speed of the vehicle;

a speed information-calculating means for calculating (1) speed information obtained from an average wheel speed of a front left wheel and a rear left wheel and (2) speed information obtained from an average speed of a front right wheel and a rear right wheel, from the rotational speeds of said wheels;

a memory means for memorizing the rotational speed of each of the wheels and the speed information of said wheels;

a judgment value-calculating means for calculating (1) a judgment value for the left side wheels by comparing the speed information obtained from the average wheel speed of the front left wheel and the rear left wheel with the ground speed of the vehicle and (2) a judgment value for the right side wheels by comparing the speed information obtained from the average wheel speed of the front right wheel and the rear right wheel with the ground speed of the vehicle;

a comparison means for comparing the judgment value for the left side wheels with a basis value for the left side wheels obtained by comparing a speed information obtained from an average speed of the front left wheel and the rear left wheel with the ground speed of the vehicle at prescribed inner pressure to obtain a comparison value for the left side wheels;

a comparison means for comparing the judgment value for the right side wheels with a basis value for the right side wheels obtained by comparing a speed information obtained from an average speed of the front right wheel and the rear right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for the right side wheels; and

a reduced pressure-judging means for judging decompression of tires by comparing the comparison values with a fixed threshold.

4. The detection device for detecting decompression of tires of claim 3, wherein the ground speed of said vehicle is determined by signals demodulated from received GPS radio waves and time.

5. A computer-readable medium storing a program for judging decompression of tires based on rotational speeds of wheels mounted on a vehicle, the program comprising:

a speed information-calculating means for calculating (1) speed information obtained from an average wheel speed of a front left wheel and a rear left wheel and (2) speed information obtained from an average speed of a front right wheel and a rear right wheel, from the rotational speeds of said wheels;

a memory means for memorizing the rotational speed of each of the wheels and the speed information of said wheels;

a judgment value-calculating means for calculating (1) a judgment value for the left side wheels by comparing the speed information obtained from the average wheel speed of the front left wheel and the rear left wheel with a ground speed of the vehicle and (2) a judgment value for the right side wheels by comparing the speed information obtained from the average wheel speed of the front right wheel and the rear right wheel with the ground speed of the vehicle;

a comparison means for comparing the judgment value for the left side wheels with a basis value for the left side wheels obtained by comparing a speed information obtained from an average speed of the front left wheel and the rear left wheel with the ground speed of the vehicle at prescribed inner pressure to obtain a comparison value for the left side wheels;

a comparison means for comparing the judgment value for the right side wheels with a basis value for the right side wheels obtained by comparing a speed information obtained from an average speed of the front right wheel and the rear right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for the right side wheels; and

a reduced pressure-judging means for judging decompression of tires by comparing the comparison values with a fixed threshold.

6. A method for detecting decompression of tires based on rotational speeds of wheels mounted on a vehicle, comprising the steps of:

detecting a rotational speed of each of said wheels;

determining a ground speed of said vehicle;

calculating (1) speed information obtained from an average wheel speed of a front left wheel and a front right wheel and (2) speed information obtained from an average speed of a rear left wheel and a rear right wheel, from the rotational speeds of said wheels;

memorizing the rotational speed of each of the wheels and the speed informations;

calculating (1) a judgment value for wheels of a front axle by comparing the speed information obtained from the average wheel speed of the front left wheel and the front right wheel with the ground speed of the vehicle and (2) a judgment value for wheels of a rear axle by comparing the speed information obtained from the average wheel speed of the rear left wheel and the rear right wheel with the ground speed of the vehicle;

comparing the judgment value for wheels of the front axle with a basis value for wheels of the front axle obtained by comparing a speed information obtained from an average speed of the front left wheel and the front right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for wheels of the front axle;

comparing the judgment value for wheels of the rear axle with a basis value for wheels of the rear axle obtained by comparing a speed information obtained from an average speed of the rear left wheel and the rear right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for wheels of the front axle; and

judging decompression of tires by comparing the comparison values with a fixed threshold.

7. The method for detecting decompression of tires of claim 6, wherein the ground speed of said vehicle is determined by signals demodulated from received GPS radio waves and time.

8. A detection device for detecting decompression of tires based on rotational speeds of wheels mounted on a vehicle, comprising:

a wheel rotational speed-detecting means for detecting a rotational speed of each of said wheels;

a ground speed calculating means for determining a ground speed of the vehicle;

a speed information-calculating means for calculating (1) speed information obtained from an average wheel speed of a front left wheel and a front right wheel and (2) speed information obtained from an average speed of a rear left wheel and a rear right wheel, from the rotational speeds of said wheels;

a memory means for memorizing the rotational speed of each of the wheels and the speed informations;

a judgment value-calculating means for calculating (1) a judgment value for wheels of a front axle by comparing the speed information obtained from the average wheel speed of the front left wheel and the front right wheel with the ground speed of the vehicle and (2) a judgment value for wheels of a rear axle by comparing the speed information obtained from the average wheel speed of the rear left wheel and the rear right wheel with the ground speed of the vehicle;

a comparison means for comparing the judgment value for wheels of the front axle with a basis value for wheels of the front axle obtained by comparing a speed information obtained from an average speed of the front left wheel and the front right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for wheels of the front axle;

a comparison means for comparing the judgment value for wheels of the rear axle with a basis value for wheels of the rear axle obtained by comparing a speed information obtained from an average speed of the rear left wheel and the rear right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for wheels of the front axle; and

a reduced pressure-judging means for judging decompression of tires by comparing the comparison values with a fixed threshold.

9. The detection device for detecting decompression of tires of claim 8, wherein the ground speed of said vehicle is determined by signals demodulated from received GPS radio waves and time.

10. A computer-readable medium storing a program for judging decompression of tires based on the rotational speeds of wheels mounted on a vehicle, the program comprising:

a speed information-calculating means for calculating (1) speed information obtained from an average wheel speed of a front left wheel and a front right wheel and (2) speed information obtained from an average speed of a rear left wheel and a rear right wheel, from the rotational speeds of said wheels;

a memory means for memorizing the rotational speed of each of the wheels and the speed informations of said wheels;

a judgment value-calculating means for calculating (1) a judgment value for wheels of a front axle by comparing the speed information obtained from the average wheel speed of the front left wheel and the front right wheel with a ground speed of the vehicle and (2) a judgment value for wheels of a rear axle by comparing the speed information obtained from the average wheel speed of the rear left wheel and the rear right wheel with the ground speed of the vehicle;

a comparison means for comparing the judgment value for wheels of the front axle with a basis value for wheels of the front axle obtained by comparing a speed information obtained from an average speed of the front left wheel and the front right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for wheels of the front axle;

a comparison means for comparing the judgment value for wheels of the rear axle with a basis value for wheels of the rear axle obtained by comparing a speed information obtained from an average speed of the rear left wheel and the rear right wheel with the ground speed of said vehicle at prescribed inner pressure to obtain a comparison value for wheels of the front axle; and

a reduced pressure-judging means for judging decompression of tires by comparing the comparison values with a fixed threshold.