Method and apparatus for receiving signals from a sensor into a tire pressure monitoring system

• US 7,705,717 B2
• Filed: 11/30/2005
• Issued: 04/27/2010
• Est. Priority Date: 11/30/2005
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Pearce, Robert, McQuade, Thomas
• Primary Examiner(s): BLOUNT, ERIC
• Application Number:
  US11/164,624
• Publication Number:
  US 20070120659A1
• Time in Patent Office: 1,609 Days
• Field of Search: 340442-447, 340/426.33, 731/46, 116/34.R, 116/34.A, 116/34.B
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0433 Radio signals
• 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

Abstract

A tire pressure monitoring system (12) for an automotive vehicle (10) has a receiver circuit (28). The vehicle (12) has a plurality of wheels (14A-14D). A plurality of antennas (31A-31D) are adjacent to one of the wheels (14A-14D). The plurality of antennas receive RF signals from a pressure sensor (16A). An adder circuit (30) is coupled to the receiver circuit and the plurality of antennas. The adder circuit receives the RF signals and adds them together to form a sum signal. The sum signal is coupled to the receiver circuit.

Claims

1. An adder circuit of a tire pressure monitoring system for coupling to a receiver having a receiver impedance comprising:

a parallel circuit comprising a plurality of branches in parallel with a receiver impedance, each branch comprising an antenna output in series with a circuit element so that each antenna output is added together and provided to the receiver;

wherein the circuit element comprises a first capacitor in parallel with an inductor.

2. An adder circuit as recited in claim 1 wherein each circuit element has a resistance approximately equal to the receiver impedance.

4. An adder circuit as recited in claim 1 wherein the circuit element comprises a series combination of a second capacitor in series with a parallel combination of said first capacitor and said inductor.

5. An adder circuit as recited in claim 1 wherein the circuit element comprises a series combination of a second capacitor in series with a parallel combination of said first capacitor and said inductor and in further series combination with a third capacitor.

3. An adder circuit of a tire pressure monitoring system for coupling to a receiver having a receiver impedance comprising:

a parallel circuit comprising a plurality of branches in parallel with a receiver impedance each branch comprising an antenna output in series with a circuit element so that each antenna output is added to ether and provided to the receiver;

wherein the circuit element comprises a resistor.

6. A tire pressure monitoring system having a receiver circuit for a vehicle having a plurality of wheels comprising:

a plurality of antennas, each of the plurality of antennas being adjacent to a respective one of the plurality of wheels, said plurality of antennas receiving RF signals from a respective one of a plurality of RF transmitters;

an adder circuit coupled to said receiver circuit and the plurality of antennas, said adder circuit receiving said RF signals and adding them together to form a sum signal, said sum signal coupled to said receiver circuit;

wherein said adder circuit comprises a first capacitor in parallel with an inductor.

7. A tire pressure monitoring system as recited in claim 6 further comprising a metal housing coupled to a ground circuit, said adder circuit disposed within the housing.

8. A tire pressure monitoring system as recited in claim 6 further comprising a plurality of coaxial connectors coupled to the housing receiving a respective one of the RF signals.

9. A tire pressure monitoring circuit as recited in claim 6 wherein the adder circuit is simultaneously coupled to each of the plurality of antennas.

10. A method for operating a tire pressure monitoring system for a vehicle having a plurality of wheels comprising:

providing a plurality of receiving antennas, each of the plurality of antennas being adjacent to a respective one of the plurality of wheels;

generating RF signals at a pressure sensor at each wheel;

coupling each of the RF signals to a respective one of the plurality of receiving antennas;

adding the output of the plurality of receiving antennas to form a sum signal;

wherein adding comprises coupling each antenna output in series with a circuit element; and

coupling the sum signal to a receiver circuit.

11. A method as recited in claim 10 wherein said circuit element comprises either a resistor or a first capacitor in parallel with an inductor.

12. A method as recited in claim 10 wherein said circuit element comprises a series combination of a second capacitor in series with a parallel combination of a first capacitor and an inductor.

13. A method as recited in claim 10 wherein the circuit element comprises a series combination of a second capacitor in series with a parallel combination of a first capacitor and an inductor and in further series combination with a third capacitor.

14. A method as recited in claim 10 wherein the receiver has a receiver impedance, wherein each circuit element has an impedance substantially equal to the receiver impedance.

15. A method as recited in claim 10 wherein adding comprises coupling each antenna output in series with a first reactive element, the parallel combination of which is coupled in series with a second reactive element.

16. A method as recited in claim 15 wherein the first and second reactive circuit element comprises a first capacitor in parallel with an inductor.

17. A method as recited in claim 15 wherein the first and second reactive circuit element comprises a series combination of a second capacitor in series with a parallel combination of a first capacitor and an inductor.

18. A method as recited in claim 15 wherein the first and second reactive circuit element comprises a series combination of a second capacitor in series with a parallel combination of a first capacitor and an inductor and in further series combination with a third capacitor.