Method and apparatus for detecting leakage rate in a tire pressure monitoring system

• US 20060010961A1
• Filed: 07/19/2004
• Published: 01/19/2006
• Est. Priority Date: 07/19/2004
• Status: Abandoned Application

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Gibson, Alex, McQuade, Thomas, Porter, Fred
• Application Number:
  US10/894,114
• Publication Number:
  US 20060010961A1
• Time in Patent Office: Days
• US Class Current: 73/40
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver

Abstract

A tire pressure monitoring system for a vehicle has been disclosed that can detect an excessive leakage rate of a tire. The system utilizes the starting pressure and starting temperature of a tire and the current pressure and current temperature of that tire with the time lapsed to determine the leakage rate of the tire. This leakage rate is compared to a leakage rate threshold. If the leakage rate is greater than the leakage rate threshold, an excessive leakage rate alert is generated.

Claims

1. A method for determining an excessive air leakage rate in a tire of a vehicle with a tire pressure monitoring system comprising:

determining a starting tire pressure of a tire of a vehicle at a first time;

determining a starting tire temperature of said tire at approximately said first time;

determining a current tire pressure of said tire at a second time;

determining a current tire temperature of said tire at approximately said second time;

determining a time lapse between said first time and said second time;

calculating a tire leakage rate of said tire based on said starting tire pressure, said starting tire temperature, said current tire pressure, said current tire temperature, and said time lapse.

2. The method of claim 1, wherein said current tire temperature is approximated by using an ambient temperature and said second time is at least two hours after said vehicle has come to rest.

3. The method of claim 1, further comprising the step of comparing said tire leakage rate to a tire leakage rate threshold.

4. The method of claim 3, further comprising the step of presenting an excessive leakage rate alert to a driver of said vehicle when said tire leakage rate exceeds said leakage rate threshold.

5. The method of claim 3, wherein said leakage rate threshold is approximately 2 psi per month.

6. The method of claim 1, wherein said first time is approximately immediately after said tire is refilled.

7. The method of claim 1, wherein said starting tire temperature is an ambient temperature and said first time is at least two hours after said vehicle has come to rest.

8. The method of claim 7, wherein said first time is approximately immediately two hours after said vehicle has come to rest after said tire is refilled.

9. The method of claim 1, further comprising the steps of storing said tire leakage rate in a performance record and associating said tire leakage rate with said second time.

10. The method of claim 1, wherein said determining said starting tire pressure comprises the step of filtering a sensed tire pressure and said determining said starting tire temperature comprises the step of filtering a sensed tire temperature.

11. The method of claim 1, wherein said determining said current tire pressure comprises the step of filtering a sensed tire pressure and said determining said current tire temperature comprises the step of filtering a sensed tire temperature.

12. A system for determining an excessive air leakage rate in a tire of a vehicle in a tire pressure monitoring system comprising:

a tire temperature sensor, said tire temperature sensor being capable of determining a starting tire temperature of a tire of a vehicle at a first time and a current tire temperature of said tire at a second time;

a tire pressure sensor, said tire pressure sensor being capable of determining a starting tire pressure of said tire at approximately said first time and a current tire pressure of said tire at approximately said second time;

a clock timer, said clock timer being capable of determining a time lapse between said first time and said second time; and

a processor, said processor being capable of calculating a tire leakage rate of said tire based on said starting tire pressure, said starting tire temperature, said current tire pressure, said current tire temperature, and said time lapse.

13. The system of claim 12, wherein said tire temperature sensor comprises an ambient temperature sensor and said second time is at least two hours after said vehicle has come to rest.

14. The system of claim 12, wherein said processor is capable of comparing said tire leakage rate to a tire leakage rate threshold.

15. The system of claim 14, wherein said leakage rate threshold is approximately 2 psi per month.

16. The system of claim 14, further comprising an output section, said output section being capable of presenting an excessive leakage rate alert to a driver of said vehicle when said tire leakage rate exceeds said leakage rate threshold.

17. The system of claim 16, wherein said output section comprises a visual display.

18. The system of claim 12, wherein said first time is approximately immediately after said tire is refilled.

19. The system of claim 12, wherein said tire temperature sensor comprises an ambient temperature sensor and said first time is at least two hours after said vehicle has come to rest.

20. The system of claim 19, wherein said first time is approximately immediately two hours after said vehicle has come to rest after said tire is refilled.

21. The system of claim 12, further comprising a filtering module, said filtering module being capable of determining said starting tire pressure based on a sensed tire pressure and determining said starting tire temperature based on a sensed tire temperature.

22. The system of claim 12, further comprising a filtering module, said filtering module being capable of determining said current tire pressure based on a sensed tire pressure and determining said current tire temperature based on a sensed tire temperature.