Tire pressure, speed and acceleration monitoring system and method

• US 20090085733A1
• Filed: 07/22/2008
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Abandoned Application

• Current Assignee: Kisan Technologies, Inc.
• Original Assignee: Kisan Technologies, Inc.
• Inventors: Gandhi, Shrikant, Charles, Kis
• Application Number:
  US12/220,113
• Publication Number:
  US 20090085733A1
• Time in Patent Office: Days
• US Class Current: 340/443
• CPC Class Codes: B60C 23/006 having two wheels only
• CPC Class Codes: B60C 23/0428 using passive wheel mounted resonance circuits

Abstract

The tire pressure, speed and acceleration monitoring system of the present invention has a transducer mounted to the wheel of a motor vehicle and a controller mounted to a non-rotating part of the vehicle. The transducer is passive and receives its power from an interrogation signal from the controller. The transducer replies with a pressure signal. The tire pressure may be frequency encoded. This is accomplished by having a resonant circuit whose resonant frequency depends on the tire pressure. Speed and acceleration are calculated by determining when the transducer passes the receiver of the controller. Since the range of the transducer is very limited, the transducer will only respond to an interrogation signal when the transducer is next to the controller receiver. The transducer has a tire pressure fill valve.

Claims

1. A tire pressure, speed and acceleration monitoring system, comprising:

a transducer mounted to a wheel, the transducer receiving power wirelessly and transmitting a pressure signal;

a controller receiving the pressure signal.

2. The system of claim 1, wherein the controller transmits power wirelessly to the transducer.

3. The system of claim 1, wherein the pressure signal is frequency encoded.

4. The system of claim 3, wherein the transducer has a resonant circuit with a resonant frequency that is dependent upon a pressure of a tire.

5. The system of claim 4, wherein the resonant frequency of the transducer adjusts for temperature changes.

6. The system of claim 1, wherein the controller determines a speed based on a time between responses from the transducer.

7. The system of claim 1, wherein the transducer has a tire pressure fill valve.

8. A method of operating a tire pressure, speed and acceleration monitoring system, comprising the steps of:

a) transmitting an interrogation signal from a controller;

b) receiving the interrogation signal at a transducer on a rotating wheel;

c) powering the transducer using the interrogation signal.

9. The method of claim 8, further including the step of:

d) transmitting a response signal from the transducer to the controller.

10. The method of claim 8, wherein the step of transmitting the response signal includes transmitting a pressure signal.

11. The method of claim 10, wherein the step of transmitting the pressure signal includes the step of frequency encoding a tire pressure.

12. The method of claim 8, wherein the step of transmitting the interrogation signal is repeated until a response signal is received.

13. The method of claim 12, further including the step of once at least two response signals are received estimating a time for transmitting a next interrogation signal.

14. The method of claim 13, further including the step of estimating a speed based on a time differential between response signals.

15. The method of claim 14, further including the step of estimating an acceleration based on the speed measurements.

16. A tire pressure, speed and acceleration monitoring system, comprising:

a controller having an acquisition algorithm transmitting an interrogation signal; and

a transducer mounted to a wheel transmitting a response signal when the interrogation signal is received.

17. The system of claim 16, wherein the controller has a speed estimation algorithm that determines a speed based on a time interval between a pair of response signals.

18. The system of claim 16, wherein the transducer is passive.

19. The system of claim 18, wherein the response includes a pressure signal.

20. The system of claim 16, wherein the pressure transducer includes a tire pressure fill valve.