Method for detection of low leak rates in a tire

• US 8,565,959 B2
• Filed: 12/03/2004
• Issued: 10/22/2013
• 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.
• Primary Examiner(s): Algahaim, Helal A
• Assistant Examiner(s): NGUYEN, CHUONG P
• Application Number:
  US11/003,261
• Publication Number:
  US 20060122747A1
• Time in Patent Office: 3,245 Days
• Field of Search: 701 29- 31, 701 316- 321, 701/32.9, 340/426.33, 340442-449, 73146-1468, 116/34.R
• US Class Current: 701/29.1
• 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 tire air pressure as a monitored tire parameter;

b. measuring the tire parameter;

c. formulating an analytic system strategy for an evaluation of the tire parameter based upon a plurality of analytic systems, the strategy formulation selecting between the use of a single analytic system and, in the alternative, the simultaneous parallel use of a plurality of analytic systems;

d. selecting at least one analytic system for evaluating the tire parameter measurement from the plurality of analytic systems, wherein selecting at least one analytic system comprises the steps;

establishing a non-zero minimum leak rate limit (RateLimit);

establishing a non-zero low pressure threshold difference band (Low Pth);

measuring a leak rate (k); and

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

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

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

2. A method according to claim 1 wherein the communication of the conclusion based upon the analysis of the measured tire parameter comprises a low tire air pressure warning.

3. A method according to claim 1, wherein the plurality of analytic systems comprise at least a relatively lower leak rate analytic system and a relatively higher leak rate analytic system.

4. A method according to claim 3, wherein the lower leak rate and the higher leak rate analytic systems are selectively employed in the alternative based on the analytic system strategy.

5. A method according to claim 3, wherein the lower leak rate and the higher leak rate analytic systems are employed simultaneously based on the analytic system strategy.

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

measuring tire air pressure as a tire parameter;

formulating an analytic system strategy for an evaluation of the tire parameter based upon a plurality of analytic systems, the strategy formulation selecting between the use of a single analytic system and, in the alternative, the simultaneous parallel use of a plurality of analytic systems;

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

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

communicating a conclusion based upon the analysis of the measured tire parameter;

wherein the selection of at least one analytic system is at least partly based upon a leakage rate of air pressure within the tire;

wherein the communication of the conclusion based upon the analysis of the measured tire parameter comprises a low tire air pressure warning;

wherein selecting at least one analytic system comprises the steps;

establishing a non-zero minimum leak rate limit (RateLimit);

establishing a non-zero low pressure threshold difference band (Low Pth);

measuring a leak rate (k); and

using an analytic system optimally suited for the measured leak rate; and

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.

7. A method according to claim 6, further comprising the step of computing leak rate from the system energy W.

8. A method according to claim 6, further comprising the step of computing the RateLimit as a function of LowPth and a pre-selected warn time.