Method for detection of low leak rates in a tire

• US 20060122747A1
• Filed: 12/03/2004
• Published: 06/08/2006
• Est. Priority Date: 12/03/2004
• Status: Active Grant

• Current Assignee: Goodyear Tire & Rubber Company
• Original Assignee: Goodyear Tire & Rubber Company
• Inventors: Brown, Jack Edward Jr.
• Granted Patent: US 8,565,959 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• 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

Multiple leak rate methodologies are combined and operate in parallel in a system for providing optimal results under different tire conditions. The methodologies may operate continuously or alternatively. Tandem large leak rate and low leak rate algorithms and methodology, for example, may deployed in a system in which, for large leak rates, a large leak rate methodology is employed and used to trigger a warning. At some pre-designated low leak rate threshold value, the system employs a low leak rate methodology either as an exclusive diagnostic monitor or in parallel with the companion large leak rate methodology. In the low leak rate analytical system, a change in tire pressure is correlated to a change in energy within a vehicle system pursuant to the algorithm W=∫ΔP*dx and derivative algorithms are used to calculate a final time and pressure drop at the final time as a basis for issuing a low pressure warning.

Claims

1. A method for monitoring a measured tire parameter comprising the steps:

a. identifying at least one monitored tire parameter;

b. measuring the tire parameter;

c. selecting at least one analytic system for optimally evaluating the tire parameter measurement from a plurality of analytic systems;

d. analyzing the measured tire parameter by means of the selected analytic system; and

e. communicating a conclusion based upon the analysis of the measured tire parameter.

2. A method according to claim 1 wherein the measured tire parameter is tire air pressure.

3. A method according to claim 2 wherein the selection of at least one analytic system is at least partly based upon a leakage rate of air pressure within the tire.

4. A method according to claim 3 wherein the communication of the conclusion based upon the analysis of the measured tire parameter comprises a low pressure warning.

5. A method according to claim 3 wherein selecting at least one analytic system comprises the steps:

establishing a minimum leak rate limit (RateLimit);

establishing a low pressure threshold difference band (LowPth);

measuring a leak rate (K); and

using an analytic system optimally suited for the measured leak rate.

6. A method according to claim 5, wherein the plurality of analytic systems comprise at least a relatively low leak rate analytic system and a relatively high leak rate analytic system.

7. A method according to claim 6, wherein the low leak rate and the high leak rate analytic systems are selectively employed in the alternative.

8. A method according to claim 6, wherein the low leak rate and the high leak rate analytic systems are employed simultaneously.

9. A method according to claim 5 wherein the at least one analytic system comprises the steps:

representing system energy (W) as a function of tire pressure change Δ

P;

thresholding system energy (Wth) by the value of a lower rate limit as tire pressure crosses a low pressure threshold;

calculating final time (tF) at which the smaller leak rate magnitudes will cross the Wth threshold; and

computing pressure drop at tF.

10. A method according to claim 9, further comprising the step of computing leak rate from the system energy W.

11. A method according to claim 9, further comprising the step of computing the RateLimit as a function of LowPth and a pre-selected warn time.

12. A method according to claim 5 wherein at least one analytic system comprises the steps:

representing system energy (W) as a function of tire pressure change Δ

P;

thresholding system energy (Wth) by the value of a lower rate limit as tire

pressure crosses a low pressure threshold difference band (LowPth).

13. A method according to claim 12, further comprising the step of computing a leak rate from system energy W.

14. A method according to claim 13, further comprising the step of computing the RateLimit as a function of LowPth and a pre-selected warn time.

15. A method for providing a warning when air pressure within a tire changes at a relatively low rate comprising the steps:

a. representing system energy (W) as a function of tire pressure change Δ

P;

b. thresholding system energy (Wth) by the value of a lower rate limit as tire pressure crosses a low pressure threshold;

c. calculating final time (tF) at which the smaller leak rate magnitudes will cross the Wth threshold;

d. computing pressure drop at tF; and

e. issuing a warning predicated on the pressure drop at tF.

16. A method according to claim 15, further comprising the step of computing a leak rate from the system energy W.

17. A method according to claim 15 wherein the representation of system energy W as a function of tire pressure change is represented by the algorithm W=∫

Δ

P*dx.

18. A method for providing a warning when air pressure within a tire changes at a relatively low rate comprising the steps:

a. representing system energy (W) as a function of tire pressure change Δ

P;

b. thresholding system energy (Wth) by the value of a lower rate limit as tire pressure crosses a low pressure threshold difference band (LowPth);

c. issuing a warning predicated on the system energy (W) being larger than the threshold value (Wth).

19. A method according to claim 18, further comprising the step of computing a leak rate from the system energy W.

20. A method according to claim 18 wherein the representation of system energy W as a function of tire pressure change is represented by the algorithm W=∫

Δ

P*dx.