System and method for detecting a rapid leak from a tire

• US 20050280522A1
• Filed: 06/17/2005
• Published: 12/22/2005
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Johnson Controls Automotive Electronic (Johnson Controls International plc)
• Inventors: Verrier, Cyrille, Leberon, Regis
• Granted Patent: US 7,432,801 B2
• Time in Patent Office: Days
• US Class Current: 340/442
• 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 detecting a rapid leak of gas contained in an automobile tire based on periodic measurements of a pressure Pa and a temperature Ta of the gas. The method includes determining a reference pressure Pcref, calculating an alarm threshold pressure Sref from the reference pressure Pcref, calculating a temperature-compensated pressure Pc at each measurement acquisition period, and comparing the compensated pressure Pc with the alarm threshold pressure Sref, wherein the leak is detected if the compensated pressure Pc is less than the alarm threshold pressure Sref.

Claims

1. A method of detecting a rapid leak of gas contained in an automobile tire based on periodic measurements of a pressure Pa and a temperature Ta of the gas, the method comprising:

determining a reference pressure Pc_ref;

calculating an alarm threshold pressure S_ref from the reference pressure Pc_ref;

calculating a temperature-compensated pressure Pc at each measurement acquisition period; and

comparing the compensated pressure Pc with the alarm threshold pressure S_ref, wherein the leak is detected if the compensated pressure Pc is less than the alarm threshold pressure S_ref.

2. The method as claimed in claim 1, wherein the reference pressure Pc_ref is measured in a cold state and is temperature-compensated.

3. The method as claimed in claim 2, wherein the compensated pressure is calculated in accordance with a formula Pc=Pa*T₂₀/Ta, wherein T₂₀ is a reference Kelvin temperature.

4. The method as claimed in claim 1, wherein the reference pressure Pc_ref is measured at at least one of a predetermined time after a last stop and at a time of ignition of a vehicle including the tire.

5. The method as claimed in claim 1, wherein the alarm threshold pressure S_ref is determined as a function of a safety threshold So.

6. The method as claimed in claim 5, wherein the safety threshold So ranges between 2% and 25% of a nominal pressure of the tires, preferably between 10 and 15%.

7. The method as claimed in claim 5, wherein the alarm threshold pressure is calculated in accordance with a formula S_ref=Pc_ref−

So.

8. A system for detecting a rapid leak of gas contained in an automobile tire based on periodic measurements of a pressure Pa and a temperature Ta of the gas, the system comprising:

a tire pressure monitoring system configured to transmit temperature information and pressure information; and

a leak detection computing system configured to

receive the temperature information and pressure information;

determine a reference pressure Pc_ref and calculate an alarm threshold pressure S_ref from the reference pressure Pc_ref,

calculate a temperature-compensated pressure Pc at each measurement acquisition period, and

compare the compensated pressure Pc with the alarm threshold pressure S_ref, wherein the leak is detected if the compensated pressure Pc is less than the alarm threshold pressure S_ref.

9. The system as claimed in claim 8, wherein the reference pressure Pc_ref is measured in a cold state and is temperature-compensated.

10. The system as claimed in claim 9, wherein the compensated pressure is calculated in accordance with a formula Pc=Pa*T₂₀/Ta, wherein T₂₀ is a reference Kelvin temperature.

11. The system as claimed in claim 8, wherein the reference pressure PC_ref is measured at at least one of a predetermined time after a last stop and at a time of ignition of a vehicle including the tire.

12. The system as claimed in claim 8, wherein the alarm threshold pressure S_ref is determined as a function of a safety threshold So.

13. The system as claimed in claim 12, wherein the safety threshold So ranges between 2% and 25% of a nominal pressure of the tires, preferably between 10 and 15%.

14. The system as claimed in claim 12, wherein the alarm threshold pressure is calculated in accordance with a formula S_ref=Pc_ref−

So.

15. A program product for detecting a rapid leak of gas contained in an automobile tire based on periodic measurements of a pressure Pa and a temperature Ta of the gas, comprising machine-readable program code for causing, when executed, one or more machines to perform the following method steps, the method comprising:

determining a reference pressure;

calculating an alarm threshold pressure from the reference pressure Pc_ref;

calculating a temperature-compensated pressure at each measurement acquisition period; and

comparing the temperature-compensated pressure with the alarm threshold pressure, wherein the leak is detected if the temperature-compensated pressure is less than the alarm threshold pressure.

16. The system as claimed in claim 15, wherein the reference pressure is measured in a cold state and is temperature-compensated.

17. The system as claimed in claim 16, wherein the compensated pressure is calculated in accordance with temperature-compensated pressure equal to (an absolute pressure times a reference Kelvin temperature) divided by absolute temperature of the gas in the tire.

18. The system as claimed in claim 15, wherein the reference pressure is measured at at least one of a predetermined time after a last stop or at a time of ignition of a vehicle including the tire.

19. The system as claimed in claim 15, wherein the alarm threshold pressure S_ref is determined as a function of a safety threshold So.

20. The system as claimed in claim 19, wherein the alarm threshold pressure is calculated in accordance with a formula S_ref=PC_ref−

So.