Method and apparatus for identifying remote sending units in a tire pressure monitor system of a vehicle using secondary modulation of wheel rotation

• US 20020101340A1
• Filed: 01/11/2001
• Published: 08/01/2002
• Est. Priority Date: 01/14/2000
• Status: Active Grant

• Current Assignee: Sensata Technologies Incorporated (Sensata Technologies Holding Plc)
• Original Assignee: Schrader-Bridgeport International Incorporated (Pacific Industrial Company Limited)
• Inventors: Starkey, Fred L.
• Granted Patent: US 6,417,766 B1
• 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

Abstract

A remote tire monitoring system (10) includes tire monitors (12) positioned at respective wheels of a vehicle (V) for transmitting radio signals modulated by tire data and modulation means positioned above near the tire monitors for imposing a secondary modulation on the radio signals. A receiver (14) receives the radio signals and recovers the tire data (26) from the radio signals and associates the tire monitor with the respective wheels of the vehicle using the secondary modulation.

Claims

1. A method for operating a remote tire monitor system including a plurality of sending units associated with wheels positioned on a vehicle and a receiving unit, the method comprising:

at at least one of the sending units, transmitting radio signals including tire data related to a tire associated with the sending unit;

at the receiving unit, receiving the radio signals;

recovering the tire data from the radio signal;

detecting secondary variations in the radio signals; and

associating a particular secondary variation with a particular wheel position.

2. The method of claim 1 wherein receiving the radio signals comprises:

detecting a primary modulation of a carrier signal transmitted by the particular sending unit; and

detecting a secondary modulation of the carrier signal due to environmental variations associated with the particular wheel position.

3. The method of claim 2 wherein detecting a secondary modulation comprises:

detecting variation in the carrier signal associated with rotational movement of the particular sending unit past structures adjacent the particular wheel position.

4. The method of claim 1 further comprising:

comparing the secondary variations in the radio signals with stored data; and

when the particular secondary variation for the particular wheel position matches stored data, associating the tire data with stored tire information for the particular sending unit.

6. The method of claim 1 further comprising:

comparing the secondary variations in the radio signals with stored data; and

using the particular secondary variation, associating the tire data with a particular sending unit at the particular wheel position on the vehicle.

7. A remote tire monitoring system comprising:

a plurality of tire monitors associated with wheels of a vehicle and configured to transmit radio signals conveying tire data; and

a receiver configured to receive the radio signals, the receiver including a circuit which detects secondary variations in the radio signals due to movement of the plurality of tire monitors.

8. The remote tire monitoring system of claim 7 further comprising:

one or more components positionable near respective tire monitors for imposing the secondary variations on the radio signals.

9. The remote tire monitoring system of claim 8 wherein the one or more components comprise metallic elements positionable along circumferential paths of the tire monitors on the wheels of the vehicle to alter the radio signals received by the receiver.

10. The remote tire monitoring system of claim 7 wherein the receiver comprises:

an identification circuit responsive to the secondary variations to identify a particular wheel location based on the secondary variations.

11. The remote tire monitoring system of claim 10 wherein the receiver further comprises:

a decoder which detects position data in the secondary variations.

12. The remote tire monitor system of claim 11 wherein the decoder comprises a ratiometric decoder responsive to the relative duration of bits of the duration data to decode the position data.

13. The remote tire monitoring system of claim 10 wherein the receiver further comprises:

a demodulator which demodulates the radio signals to receive the tire data.

15. The remote tire monitoring system of claim 14 wherein the tire monitor means comprises:

a plurality of remote tire monitors mounted on the respective wheels of the vehicle and to monitor a tire condition and produce the tire data, each remote tire monitor transmitting respective radio signals.

16. The remote tire monitoring system of claim 15 modulation means comprises:

groupings of one or more components mountable near the circumferential path of respective tire monitors, a each grouping producing a unique secondary modulation on the radio signals transmitted by the respective tire monitor.

17. The remote tire monitoring system of claim 15 wherein the modulation means comprises alteration means for selectively absorbing and reflecting the radio signals. 18. The remote tire monitoring system of claim 14 wherein the decoding means comprises

a ratiometric decoder responsive to relative duration of the secondary modulation to decode position data for associating the tire monitor means with the respective wheels of the vehicle.

14. A remote tire monitoring system comprising:

tire monitor means positioned at respective wheels of a vehicle for transmitting radio signals modulated by tire data;

modulation means positionable near the tire monitor means for imposing a secondary modulation on the radio signals; and

receiving means for receiving the radio signals, the receiving means including;

demodulation means for recovering the tire data from the radio signals, and

decoding means responsive to the secondary modulation for associating the tire data with respective wheel locations of the vehicle.