Method and device for monitoring tire pressure utilizing a reference value that evolves according to a predetermined function of time

• US 8,011,236 B2
• Filed: 04/13/2006
• Issued: 09/06/2011
• Est. Priority Date: 04/13/2005
• Status: Expired due to Fees

• Current Assignee: Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA), TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA), TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Branger, Laurent
• Primary Examiner(s): Caputo; Lisa M
• Assistant Examiner(s): JENKINS, JERMAINE L
• Application Number:
  US11/910,171
• Publication Number:
  US 20090308150A1
• Time in Patent Office: 1,972 Days
• Field of Search: None
• US Class Current: 73/146.2
• 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 method of monitoring a pressure (P) of a tire of a motor vehicle involves measuring a pressure (P) of the tire and comparing the measured pressure with at least one reference value (P_r^M, P_r^m, P_r). The reference value (P_r^M, P_r^m, P_r) varies in accordance with a temporal law that depends on at least one of the following parameters: a temporal benchmark, a speech of the vehicle, a temperature of the tire, and a parameter that is based on at least one of the previous three parameters. The reference value (P_r^M, P_r^m, P_r) varies between first and second extreme values.

Claims

1. A method for monitoring a pressure of a tire of a motor vehicle, comprising steps of:

measuring a pressure of the tire;

comparing the measured pressure with a reference value that varies in accordance with a temporal law,

wherein the temporal law depends on at least one of;

a temporal benchmark,

a speed of the vehicle, and

a temperature of the tire, and

wherein the reference value varies between first and second extreme values;

enabling the reference value to evolve according to a first predetermined function of time, if the vehicle is running at a speed greater than a predetermined threshold speed and so long as the second extreme value is not attained; and

enabling the reference value to evolve according to a second predetermined function of time, if the vehicle has stopped or is running at a speed less than the predetermined threshold speed and so long as the first extreme value is not attained.

2. The method of claim 1, wherein the temporal law depends on a type of the tire.

3. The method of claim 1,

wherein the reference value is a minimum pressure, and

further comprising a step of triggering a warning signal if the measured pressure is less than the reference value.

4. The method of claim 1,

wherein the reference value is a maximum pressure, and

further comprising a step of triggering a warning signal if the measured pressure is greater than the reference value.

5. The method of claim 1, wherein a range between the first and second extreme values is greater than or equal to about 100 mbar.

6. The method of claim 1, wherein a range between the first and second extreme values is less than or equal to about 200 mbar.

7. The method of claim 5, wherein the first and second extreme values correspond to first and second states of the tire, such that the tire is hotter in the second state than in the first state.

8. The method of claim 6, wherein the first and second extreme values correspond to first and second states of the tire, such that the tire is hotter in the second state than in the first state.

9. The method of claim 1, wherein the predetermined threshold speed is greater than or equal to about 30 km/h.

10. The method of claim 1, wherein the predetermined threshold speed is less than or equal to about 50 km/h.

11. The method of claim 1, wherein the first function of time is an affine function that increases according to a first predetermined director coefficient, and wherein the second function of time is an affine function that decreases according to a second predetermined director coefficient.

12. The method of claim 11, wherein the first director coefficient lies between about 500 and 700 mbar/h.

13. The method of claim 11, wherein the second director coefficient lies between about 150 and 250 mbar/h.

14. The method of claim 1, further comprising steps of:

determining whether the vehicle is in a stopped state or a running state;

on passing from a running state to a stopped state, storing data on when stoppage occurred and a reference value corresponding to when stoppage occurred; and

on returning to a running state, using an estimated reference value that takes into account the stored reference value and the stored data of when the stoppage occurred.

15. A device onboard a motor vehicle, the device comprising a processor programmed to implement a method in accordance with claim 1, for monitoring a pressure of a tire of the motor vehicle.

16. A computer system comprising a processor programmed to implement a method in accordance with claim 1, for monitoring a pressure of a tire of a motor vehicle.

17. A computer-readable storage medium storing a program that, when implemented, causes a computer to perform a method in accordance with claim 1, for monitoring a pressure of a tire of a motor vehicle.