Determination of wheel sensor position using a wireless solution

• US 20030197603A1
• Filed: 04/18/2002
• Published: 10/23/2003
• Est. Priority Date: 04/18/2002
• Status: Active Grant

• Current Assignee: Sensata Technologies Incorporated (Sensata Technologies Holding Plc)
• Original Assignee: Schrader-Bridgeport International Incorporated (Pacific Industrial Company Limited)
• Inventors: McCall, Alan Kenneth, Strahan, Samuel Kane, Jordan, Trevor Anthony, Molyneaux, Nevin Robert, Boudaoud, Idir, Stewart, William David
• Granted Patent: US 7,010,968 B2
• Time in Patent Office: Days
• US Class Current: 340/442
• CPC Class Codes: B60C 23/0416 allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right
• CPC Class Codes: B60C 23/0444 Antenna structures, control or arrangements thereof, e.g. for directional antennas, diversity antenna, antenna multiplexing or antennas integrated in fenders
• CPC Class Codes: B60C 23/0462 Structure of transmission protocol

Abstract

A tire monitor for use in conjunction with a remote tire monitoring system of a vehicle includes in one embodiment a dual-axis accelerometer and a control circuit. The control circuit determines position information such as the right/left position of the tire monitor on the vehicle in response to an acceleration signal from the dual axis accelerometer. The tire monitor transmits tire data and the position information to a control unit of a remote tire monitor system. The control unit determines additional position information such as front/rear position of the transmitting tire monitor by detecting signal strength of the transmission. This allows the system to automatically re-learn the position of tire monitors on the vehicle, even after tire rotation.

Claims

1. A tire monitor for use in conjunction with a remote tire monitoring system of a vehicle, the tire monitor comprising:

a dual-axis accelerometer; and

a control circuit configured to determine position information about position of the tire monitor on the vehicle in response to an acceleration signal from the dual axis accelerometer.

2. The tire monitor of claim 1 further comprising:

a tire sensing device which detects a tire condition and produces tire data in response thereto;

a radio frequency stage coupled with the control circuit to transmit tire information including tire information based on the tire data and position information.

3. The tire monitor of claim 1 wherein the dual-axis accelerator comprises:

an output coupled with the control circuit to provide the acceleration signal.

4. The tire monitor of claim 3 wherein the acceleration signal comprises:

a first axis acceleration signal representative of acceleration along a first axis; and

a second axis acceleration signal representative of acceleration along a second axis;

5. The tire monitor of claim 4 wherein the first axis and the second axis are orthogonal with a rotation axis.

12. The remote tire monitoring system of claim 11 wherein the accelerometer is configured to provide accelerometer signals indicative of acceleration in two or more axes substantially in a rotational plane of the respective tire with which the each tire monitor is associated.

13. The remote tire monitoring system of claim 12 wherein the monitor position information determining circuit is configured to receive the accelerometer signals and determine right/left position information for the each tire monitor.

14. The remote tire monitoring system of claim 13 wherein the control circuit is configured to determine an amount of signal received from each respective position information radio transmitting circuit.

15. The remote tire monitoring system of claim 14 wherein the respective tire monitor position determining circuit is configured to determine front/rear position information based on the amount of signal received for each respective position information radio transmitting circuit.

6. A tire monitor method comprising:

at a tire monitor, determining first acceleration along a first axis and second acceleration along a second axis; and

based on the first acceleration and the second acceleration, determining position information about position of the tire monitor on a vehicle.

7. The tire monitor method of claim 6 further comprising:

based on the first acceleration and the second acceleration, determining rotational direction of a wheel associated with the tire monitor; and

determining the position information based on the rotational direction.

8. The tire monitor method of claim 7 further comprising:

producing a first acceleration signal based on the first acceleration and a second acceleration signal based on the second acceleration;

determining a lag/lead relationship of the first acceleration signal and the second acceleration signal; and

determining the rotational direction based on the lag/lead relationship.

9. The tire monitor method of claim 6 further comprising:

transmitting radio signals to communicate data representative of the position information;

determining a received amount of the radio signals; and

based on the received amount, determining additional position information about the position of the tire monitor on the vehicle.

10. The tire monitor method of claim 9 wherein the position information comprises right/left position information and the additional position information comprises front/rear position information.

11. A remote tire monitoring system for a vehicle, the remote tire monitoring system comprising:

a plurality of tire monitors associated with respective tires of the vehicle,

each tire monitor including

an accelerometer,

a monitor position information determining circuit responsive to an acceleration signal from the accelerometer, and

a position information radio transmitting circuit; and

a control circuit including

a position information radio receiving circuit, and

a respective tire monitor position determining circuit.

16. A tire monitor for use in a remote tire monitor system for tires of a vehicle, the tire monitor comprising:

means for determining a direction of rotation of an associated wheel;

means for determining right/left position information based on the direction of rotation; and

transmitting means for transmitting data related to the right/left position information for the tire monitor.

17. A tire monitor method for a tire monitor positioned at a wheel of a vehicle, the tire monitor method comprising:

receiving a tire motion indication;

sampling an accelerometer signal produced by a multiple-axis accelerometer;

determining rotation direction for the wheel based on the accelerometer signal;

determining position information for the wheel based on the rotation direction; and

transmitting data to a remote receiver based on the position information.

18. The tire monitor method of claim 17 further comprising:

powering up the accelerometer prior to sampling the accelerometer signal; and

powering down the accelerometer after determining the rotation direction of the wheel.

19. A tire monitor method for a tire monitor positioned at a wheel of a vehicle, the tire monitor method comprising:

sampling an accelerometer signal produced by a multiple-axis accelerometer;

if an acceleration indication of the accelerometer signal exceeds a threshold,

determining rotation direction for the wheel based on the accelerometer signal;

determining position information for the wheel based on the rotation direction; and

transmitting data to a remote receiver based on the position information.

20. The tire monitor method of claim 19 further comprising:

waiting for a predetermined triggering event;

powering up the accelerometer to sample the accelerometer signal;

if vehicle speed as indicated by the accelerometer signal does not exceed a threshold, powering down the accelerometer; and

waiting for a subsequent triggering event.

21. The tire monitor method of claim 20 further comprising:

comparing the acceleration indication with a turn on threshold to determine the vehicle speed.

22. The tire monitor method of claim 20 further comprising:

comparing the acceleration indication with a turn on threshold to determine if the vehicle is travelling forward or in reverse.

23. The tire monitor method of claim 20 further comprising:

if the vehicle speed exceeds the threshold, determining if the vehicle speed has previously exceeded the threshold;

if the vehicle speed has previously exceeded the threshold, powering down the accelerometer; and

waiting for a subsequent triggering event.

24. A tire monitor method comprising:

at a tire monitor associated with a tire of a vehicle, determining right/left position data based on acceleration detected at a dual axis accelerometer;

at the tire monitor, determining a vehicle acceleration condition from the dual axis accelerometer;

at the tire monitor, determining tire pressure data associated with the acceleration condition; and

transmitting from the tire monitor tire pressure information, acceleration information related to the acceleration condition and right/left position information for determination of position of the tire monitor on the vehicle.

25. The tire monitor method of claim 24 further comprising:

at a control unit of the vehicle, receiving the tire pressure information, the acceleration information and the right/left position information;

determining one of a braking and an accelerating condition for the vehicle based on the acceleration information; and

determining front/rear position information for the tire monitor based on the determined braking or accelerating condition.

26. The tire monitor method of claim 24 further comprising:

at a control unit of the vehicle, receiving respective tire pressure information, respective acceleration information and respective right/left position information from a plurality of tire monitors;

selecting two or more tire monitors based on the respective right/left position information;

determining one of a braking and an accelerating condition for the vehicle based on the respective acceleration information; and

determining front/rear position information for each tire monitor of the two or more tire monitors based on the determined respective braking or accelerating condition.

27. The tire monitor method of claim 24 further comprising:

detecting acceleration of the vehicle based on an acceleration signal from the dual axis accelerometer;

comparing the detected acceleration with an acceleration threshold; and

transmitting the acceleration information only when the detected acceleration exceeds the acceleration threshold.

28. The tire monitor method of claim 24 wherein determining tire pressure data comprises:

determining a variation in tire pressure from a tire pressure baseline value.

29. The tire monitor method of claim 28 wherein transmitting tire pressure information comprises:

transmitting information about the variation in tire pressure.

30. A tire monitor method for a tire monitor system of a vehicle, the tire monitor method comprising:

receiving tire monitor transmissions from tire monitors positioned at all wheels of the vehicle,

determining left/right position information for each of the tire monitors to identify right side tire monitors and left side tire monitors; and

subsequently, determining which right side tire monitor is a right-front tire monitor and which right side tire monitor is a right-rear tire monitor, and determining which left side tire monitor is a left-front tire monitor and which left side tire monitor is a left-rear tire monitor.

31. The tire monitor method of claim 30 further comprising:

determining amount of signal received for respective tire monitor transmissions; and

distinguishing the right-rear tire monitor from the right-front tire monitor and the left-rear tire monitor from the left-front tire monitor based on the amount of signal received.

32. The tire monitor method of claim 31 wherein determining left/right position information for each of the tire monitors comprises:

detecting left/right position data contained in each respective tire monitor transmission.