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

• US 7,305,288 B2
• Filed: 05/11/2004
• Issued: 12/04/2007
• Est. Priority Date: 06/09/2003
• Status: Expired due to Fees

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: SRI Sports Limited (Sumitomo Rubber Industries Limited)
• Inventors: Yanase, Minao
• Primary Examiner(s): Chin; Gary
• Application Number:
  US10/842,579
• Publication Number:
  US 20040249528A1
• Time in Patent Office: 1,302 Days
• Field of Search: 701/1, 701/29, 340442-445, 731/46, 731/465
• 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

Abstract

A method for detecting decrease in tire air-pressure on the basis of wheel rotational information obtained from tires attached to a four-wheeled vehicle. The method includes the steps of: obtaining wheel rotational information obtainable from the respective tires, storing the wheel rotational information, and judging decrease in air-pressure of a tire. The step of judging decrease in air-pressure includes the step of adjusting a sensitivity of judgment upon multiplying a specified sensitivity coefficient to the wheel rotational information of the respective wheels of a front axis or those of the respective wheels of a rear axis of the vehicle and of judging a running condition of the vehicle. When it is determined that the vehicle is performing straight-ahead running, the judgment of decrease in tire air-pressure is performed only on the basis of wheel rotational information when performing straight-ahead running. It is possible to maintain detection accuracy of decrease in tire air-pressure and to prevent erroneous alarm.

Claims

1. A method for detecting decrease in tire air-pressure on the basis of wheel rotational information obtained from tires attached to a four-wheeled vehicle, comprising the steps of:

obtaining wheel rotational information by subjecting rotational information obtained from the respective tires to an initial correction on the basis of the rotational information, to eliminate the influence of initial differences in the tires;

storing the wheel rotational information; and

judging decrease in air-pressure of a tire to obtain a judgment of decrease in tire air-pressure, wherein

the step of judging decrease in air-pressure includes (1) adjusting a sensitivity of judgment by multiplying a specified sensitivity coefficient to the wheel rotational information of (a) the respective wheels of a front axis or (b) the respective wheels of a rear axis of the vehicle and (2) judging a running condition of the vehicle, and wherein

when it is determined that the vehicle is performing straight-ahead running, the judgment of decrease in tire air-pressure is performed only on the basis of said wheel rotational information by eliminating data during turning movements when performing said straight-ahead running.

2. A method for detecting decrease in tire air-pressure on the basis of wheel rotational information obtained from tires attached to a four-wheeled vehicle, comprising the steps of:

obtaining wheel rotational information by subjecting rotational information obtained from the respective tires to an initial correction on the basis of the rotational information, to eliminate the influence of initial differences in the tires;

storing the wheel rotational information; and

judging decrease in air-pressure of a tire, wherein

the step of judging decrease in air-pressure includes (1) adjusting a sensitivity of judgment by multiplying a specified sensitivity coefficient to the wheel rotational information of (a) the respective wheels of a front axis or (b) the respective wheels of a rear axis of the vehicle and (2) judging a running condition of the vehicle, and wherein

a judged value for judging decease in tire air-pressure when performing turning movements is corrected on the basis of said wheel rotational information, said sensitivity coefficient, tread width and tuning radius when it is determined that the vehicle is performing said turning movements.

3. An apparatus for detecting decrease in tire air-pressure in which decrease in tire air-pressure is detected on the basis of wheel rotational information obtained from tires attached to a four-wheeled vehicle, comprising:

rotational information detecting means which obtain wheel rotational information by subjecting rotational information obtainable from the respective tires to an initial correction on the basis of the rotational information, to eliminate the influence of initial differences in the tires;

a storing means which stores the wheel rotational information; and

a decompression judging means which judges decrease in air-pressure of a tire, wherein the decompression judging means includes

a sensitivity adjusting means which adjusts a sensitivity of judgment by multiplying a specified sensitivity coefficient to the wheel rotational information of (a) the respective wheels of a front axis or (b) the respective wheels of a rear axis of the vehicle,

a running judging means which judges a running condition of the vehicle, and

a decompression judgment starting means which performs judgment of decrease in tire air-pressure, when it is determined that the vehicle is performing straight-ahead running, only on the basis of wheel rotational information by eliminating data during turning movements when performing straight-ahead running.

4. An apparatus for detecting decrease in tire air-pressure in which decrease in tire air-pressure is detected on the basis of wheel rotational information obtained from tires attached to a four-wheeled vehicle, comprising:

rotational information detecting means which obtain wheel rotational information by subjecting rotational information obtainable from the respective tires to an initial correction on the basis of the rotational information, to eliminate the influence of initial differences in the tires;

a storing means which stores the wheel rotational information; and

a decompression judging means which judges decrease in air-pressure of a tire to obtain a judged value, wherein the decompression judging means includes

a sensitivity adjusting means which adjusts a sensitivity of judgment by multiplying a specified sensitivity coefficient to the wheel rotational information of (a) the respective wheels of a front axis or (b) the respective wheels of a rear axis of the vehicle,

a ring judging means which judges a running condition of the vehicle, and

a correcting means which corrects the judged value when performing turning movements obtained by the decompression judging means on the basis of said wheel rotational information, said sensitivity coefficient, tread width and tuning radius when it is determined that the vehicle is performing said tuning movements.

5. A computer readable medium for storing a program for judging decompression of a tire, in which for judging decrease in tire air-pressure on the basis of wheel rotational information obtained from tires attached to a four-wheeled vehicle, a computer uses said program to function as

a storing means which stores wheel rotational information, obtained by subjecting rotational information obtained from the respective tires to an initial correction on the basis of the rotational information, to eliminate the influence of initial differences in the tires,

a decompression judging means which judges decrease in air-pressure of a tire,

a sensitivity adjusting means which adjusts a sensitivity of judgment by multiplying a specified sensitivity coefficient to the wheel rotational information of (a) the respective wheels of a front axis or (b) the respective wheels of a rear axis of the vehicle,

a running judging means which judges a running condition of the vehicle, and

a decompression judgment staring means which performs judgment of decrease in tire air-pressure, when it is determined that the vehicle is performing straight-ahead running, only on the basis of said wheel rotational information by eliminating data during turning movements when performing said straight-ahead running.

6. A computer readable medium for storing a program for judging decompression of a tire, in which for judging decrease in tire air-pressure on the basis of wheel rotational information obtained from tires attached to a four-wheeled vehicle, a computer uses said program to function as

a storing means which stores the wheel rotational information, obtained by subjecting rotational information obtained from the respective tires to an initial correction on the basis of the rotational information, to eliminate the influence of initial differences in the tires,

a decompression judging means which judges decrease in air-pressure of a tire to obtain a judged value,

a sensitivity adjusting means which adjusts a sensitivity of judgment upon multiplying a specified sensitivity coefficient to the wheel rotational information of (a) the respective wheels of a front axis or (b) the respective wheels of a rear axis of the vehicle,

a running judging means which judges a running condition of the vehicle, and

a correcting means which corrects the judged value when performing turning movements obtained by the decompression judging means on the basis of said wheel rotational information, said sensitivity coefficient, tread width and turning radius when it is determined that the vehicle is performing said turning movements.