METHOD AND APPARATUS FOR DETECTING DECREASE IN TIRE AIR PRESSURE AND PROGRAM FOR DETERMINING DECREASE IN TIRE AIR PRESSURE

• US 20090261961A1
• Filed: 03/20/2009
• Published: 10/22/2009
• Est. Priority Date: 04/16/2008
• Status: Abandoned Application

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: MIYAMOTO, Kazuyoshi
• Application Number:
  US12/408,307
• Publication Number:
  US 20090261961A1
• Time in Patent Office: Days
• US Class Current: 340/444
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00

Abstract

A method of detecting a decrease in a tire air pressure based on wheel rotation information obtained from tires attached to a four-wheel vehicle. The method includes: a step of calculating wheel rotation information obtained from the respective wheel tires; a step of computing the first to the third judgment values DEL1, DEL2, and DEL3; a step of storing the wheel rotation information, the first judgment value, the second judgment value, and the third judgment value; a step of setting judgment conditions for the first judgment value, the second judgment value, and the third judgment value with regard to the respective wheel tires; and a step of judging, based on the judgment conditions, a decrease in the air pressures of the respective wheel tires. The step of setting the judgment condition sets threshold values used for the judgment conditions depending on a status of a road on which a vehicle runs, a turning level of the vehicle, or a level of the running of the vehicle running on an uphill or a downhill.

Claims

1. A method of detecting a decrease in a tire air pressure based on wheel rotation information obtained from tires attached to a four-wheel vehicle, comprising:

a step of calculating wheel rotation information obtained from the respective wheel tires;

a step of computing a first judgment value obtained by dividing a difference in the sum of wheel rotation information between two pairs of wheel tires on diagonal lines by a predetermined average wheel speed, a second judgment value obtained by dividing a difference between a sum of wheel rotation information of front wheel tires and a sum of wheel rotation information of rear wheel tires by a predetermined average wheel speed, and a third judgment value obtained by dividing a difference between a sum of wheel rotation information of right wheel tires and a sum of wheel rotation information of left wheel tires by a predetermined average wheel speed;

a step of storing the wheel rotation information, the first judgment value, the second judgment value, and the third judgment value;

a step of setting judgment conditions for the first judgment value, the second judgment value, and the third judgment value with regard to the respective wheel tires; and

a step of judging, based on the judgment conditions, a decrease in the air pressures of the respective wheel tires,

wherein the step of setting the judgment condition sets threshold values used for the judgment conditions depending on a status of a road on which a vehicle runs, a turning level of the vehicle, or a level of the running of the vehicle running on an uphill or a downhill.

2. An apparatus of detecting a decrease in a tire air pressure based on wheel rotation information obtained from tires attached to a four-wheel vehicle, comprising:

a rotation information detection means for calculating wheel rotation information obtained from the respective wheel tires;

a judgment value computation means for computing a first judgment value obtained by dividing a difference in the sum of wheel rotation information between two pairs of wheel tires on diagonal lines by a predetermined average wheel speed, a second judgment value obtained by dividing a difference between a sum of wheel rotation information of front wheel tires and a sum of wheel rotation information of rear wheel tires by a predetermined average wheel speed, and a third judgment value obtained by dividing a difference between a sum of wheel rotation information of right wheel tires and a sum of wheel rotation information of left wheel tires by a predetermined average wheel speed;

a storage means for storing the wheel rotation information, the first judgment value, the second judgment value, and the third judgment value;

a judgment condition setting means for setting judgment conditions for the first judgment value, the second judgment value, and the third judgment value with regard to the respective wheel tires; and

a judgment means for judging, based on the judgment conditions, a decrease in the air pressures of the respective wheel tires,

wherein the judgment condition setting means sets threshold values used for the judgment conditions depending on a status of a road on which a vehicle runs, a turning level of the vehicle, or a level of the running of the vehicle running on an uphill or a downhill.

3. A program for determining a decrease in a tire air pressure for causing, in order to detect a tire having a decreased pressure based on wheel rotation information obtained from tires attached to a four-wheel vehicle, a computer to function as:

a rotation information detection means for calculating wheel rotation information obtained from the respective wheel tires;

a judgment value computation means for computing a first judgment value obtained by dividing a difference in the sum of wheel rotation information between two pairs of wheel tires on diagonal lines by a predetermined average wheel speed, a second judgment value obtained by dividing a difference between a sum of wheel rotation information of front wheel tires and a sum of wheel rotation information of rear wheel tires by a predetermined average wheel speed, and a third judgment value obtained by dividing a difference between a sum of wheel rotation information of right wheel tires and a sum of wheel rotation information of left wheel tires by a predetermined average wheel speed;

a storage means for storing the wheel rotation information, the first judgment value, the second judgment value, and the third judgment value;

a judgment condition setting means for setting judgment conditions for the first judgment value, the second judgment value, and the third judgment value with regard to the respective wheel tires; and

a judgment means for judging, based on the judgment conditions, a decrease in the air pressures of the respective wheel tires,

wherein the judgment condition setting means sets threshold values used for the judgment conditions depending on a status of a road on which a vehicle runs, a turning level of the vehicle, or a level of the running of the vehicle running on an uphill or a downhill.