System and method for diagnosing loss of pressure in tires of a vehicle

• US 5,764,137 A
• Filed: 12/09/1996
• Issued: 06/09/1998
• Est. Priority Date: 12/09/1996
• Status: Expired due to Term

• Current Assignee: FCA US LLC (Stellantis NV)
• Original Assignee: Chrysler Corporation (Stellantis NV)
• Inventors: Zarkhin, Mikhail
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US08/761,953
• Time in Patent Office: 547 Days
• Field of Search: 340/444, 340/443, 340/442, 73/146.2, 73/146, 73/146.5
• 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 system and method for diagnosing when a tire of a vehicle is beginning to lose pressure. The vehicle has four wheels, and four associated tires mounted thereon, each with an associated angular speed when the vehicle is in motion. Four wheel speed sensors are attached to one of the four wheels of the vehicle for sensing the angular speed of each wheel. A microprocessor is also included that is electrically coupled to each of the wheel speed sensors for receiving the angular speed of each wheel. The microprocessor integrates, over time, the angular speed of each wheel. An indicator is also provided that is coupled to the microprocessor for indicating that a tire of the vehicle is losing pressure if the microprocessor determines that the integral of the angular speed of one of the tires is greater than the integral of the angular speed of the other tires. A method is also provided for diagnosing when one of the vehicle tires is beginning to lose pressure, such as in the case of a slow leak.

Claims

1. A system for diagnosing loss of tire pressure in tires of a vehicle, the system comprising:

a wheel having a corresponding tire mounted thereon;

a wheel speed sensor attached to each wheel for sensing an angular speed of the wheel; and

a microprocessor electrically coupled to each of the wheel speed sensors for receiving the angular speed of each wheel, the microprocessor integrating, over time, the angular speed of each wheel to yield a set of integrated angular speeds determining a maximum value from the set of integrated angular speeds, determining a set of value differences consisting of the differences between the maximum value and each of the integrated angular speeds, determining a maximum value difference from among the set of value differences determining if the maximum value difference is greater than a predetermined threshold value and determining that there is loss of tire pressure in a tire if the determined maximum value difference is greater than the predetermined threshold value.

2. A method for diagnosing loss of tire pressure in tires of a vehicle, the method comprising the steps of;

measuring an angular speed of a wheel having a tire mounted thereon;

determining an integral of the angular speed of each wheel over time to yield a set of angular speed integrals;

determining a maximum angular speed integral value among the set of angular speed integrals;

determining for each wheel a value difference between the maximum angular seed integral value and the integral of the angular speed for each wheel, determining the maximum value difference among the value differences for each wheel and determining if the maximum value difference is above a predetermined threshold value; and

determining that there is loss of tire pressure in a tire if the determined maximum value difference is greater than the predetermined threshold value.

3. The method of claim 2 including the step of indicating there is a loss of tire pressure if a loss of tire pressure is determined.

4. The method of claim 2 including the step of determining whether another wheel on the same side of the vehicle as the wheel having a loss of tire pressure has a similar angular wheel speed.

5. The method of claim 4 including the step of determining that there is not a loss of pressure in the tire if the angular wheel speed of the wheel and the other wheel are similar.

6. A method for diagnosing loss of tire pressure in four tires of a vehicle, the method comprising the steps of:

measuring an angular speed of a wheel having a tire mounted thereon;

determining an integral of the angular speed of each wheel over time;

determining a maximum integral of the angular speed of each wheel to yield a set of maximum angular speed integrals;

determining a maximum value from the maximum angular speed integrals;

determining for each wheel a maximum value difference between the maximum value and maximum integral of the angular speed of each wheel;

determining a maximum difference from the maximum value differences;

determining if the maximum difference is above a predetermined threshold value; and

determining that a tire is losing pressure if the maximum difference is above the predetermined threshold value.

7. The method of claim 6 including the step of determining whether another wheel on the same side of the vehicle as the wheel having a loss of tire pressure has a similar angular wheel speed.

8. The method of claim 7 including the step of determining that there is not a loss of pressure in the tire if the angular wheel speed of the wheel and the other wheel are similar.