System for monitoring the pressure of tires of a motor vehicle

• US 20040066290A1
• Filed: 04/02/2003
• Published: 04/08/2004
• Est. Priority Date: 09/25/2002
• Status: Active Grant

• Current Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Hernando, Serge, Pinard, Thierry, Peghaire, Jean-Pierre
• Granted Patent: US 6,922,140 B2
• Time in Patent Office: Days
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0416 allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right
• CPC Class Codes: B60C 23/0437 Means for detecting electromagnetic field changes not being part of the signal transmission per se, e.g. strength, direction, propagation or masking
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00

Abstract

According to one exemplary embodiment, a system for monitoring the pressure of tires of a motor vehicle with location of the wheels comprises a monitoring element and a pressure sensor. Each pressure sensor is associated with a transmitter with which it transmits to the monitoring element a radio signal comprising sensor identification data. The system comprises a means for determining the phase shift between two radio signals transmitted at two distinct times for each wheel. The system further comprises a means for determining the rotation angle, modulo 2π, traveled by each of the wheels between the two times. The system further comprises a means for comparison between the phase shifts and the rotation angles.

Claims

1. A system for monitoring the pressure of tires of a motor vehicle with location of the wheels, comprising a monitoring element, one pressure sensor per wheel i associated with a transmitter with which it transmits to the monitoring element a radio signal comprising sensor identification data, the system comprising:

a means for determining the phase shift (di) between two radio signals transmitted at two distinct times (T1 and T2) for each wheel i;

a means for determining the rotation angle (Dj), modulo 2π

, traveled by each of the wheels j between the two times (T1 and T2); and

a means for comparison between the phase shifts (di) and the rotation angles (Dj).

2. The system as defined in claim 1, wherein the means for determining the rotation angle traveled by each wheel comprise means for determining the speed of each wheel.

3. The system as defined in claim 2, wherein the means are speed sensors of the vehicle'"'"'s antilock braking system.

4. The system as defined in claim 1, wherein the monitoring element comprises a means for storing the digital data at the two times (T1 and T2) corresponding to the radio signals.

5. A method of identifying the locations of wheels on a vehicle, comprising:

determining phase shifts between radio frequency signals transmitted at a plurality of times from each wheel;

determining rotation angles traveled by each wheel at the plurality of times; and

identifying the locations of the wheels on the vehicle based on the phase shifts and the rotation angles.

6. The method of claim 5, further comprising:

identifying a first period, in the range [T1, T1+t1] of a radio frequency reception level S1[T1, T1+t1] of the radio frequency signals;

identifying a second period, in the range [T2, T2+t2] of the radio frequency reception level S2[T2, T2+t2] of the radio frequency signals, wherein t1 and t2 represent one period of the radio frequency signals; and

determining the phase shifts based on the first and second periods.

7. The method of claim 5, wherein the rotation angles are determined based on the speed traveled by each wheel.

8. The method of claim 7, wherein the speed traveled by each wheel is received from an antilock braking system of the vehicle.

9. The method of claim 5, further comprising:

determining first wheel angles based on the phase shifts and second wheel angles based on the rotation angles;

ranking the first wheel angles and second wheel angles in order to create pairs of wheel angles; and

identifying the locations of the wheels based on the ranking.

10. A method of identifying the locations of wheels on a vehicle, comprising, for each of a plurality of wheels:

receiving a radio frequency signal having a periodic modulation at first and second times and determining a phase shift in the periodic modulation between the first and second times;

receiving a speed signal from a wheel speed sensor; and

identifying the locations of the wheels on the vehicle based on the phase shifts and the speed signals.

11. The method of claim 10, further comprising:

for each of the plurality of wheels, receiving the speed signal at the first and second times and determining a wheel rotation angle based on the speed signals.

12. The method of claim 11, wherein the wheel speed sensor is associated with an antilock braking system.

13. The method of claim 11, further comprising:

ranking the phase shifts and wheel rotation angles in order to create pairs of wheel angles; and

identifying the locations of the wheels based on the ranking.

14. The method of claim 10, wherein the periodic modulation is an amplitude modulation.

15. The method of claim 10, further comprising:

identifying a first period, in the range [T1, T1+t1] of a radio frequency reception level S1[T1, T1+t1] of the radio frequency signal;

identifying a second period, in the range [T2, T2+t2] of the radio frequency reception level S2[T2, T2+t2] of the radio frequency signal, wherein t1 and t2 represent one period of the radio frequency signal; and

determining the phase shifts based on the first and second periods.