Tire condition monitoring system

• US 20050151634A1
• Filed: 12/16/2004
• Published: 07/14/2005
• Est. Priority Date: 01/09/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Okumura, Ryozo, Murayama, Koji, Tsuji, Hiroyuki
• Granted Patent: US 7,202,777 B2
• Time in Patent Office: Days
• US Class Current: 340/445
• CPC Class Codes: B60C 23/0413 Wireless charging of active radio frequency circuits
• CPC Class Codes: B60C 23/0416 allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right
• CPC Class Codes: B60C 23/0442 the transmitted signal comprises further information, e.g. instruction codes, sensor characteristics or identification data
• CPC Class Codes: B60C 23/0464 to avoid signal interference

Abstract

A tire condition monitoring system is composed of a detector installed in each tire, a transmitter positioned in the vicinity of each tire, and a monitor communicating with the transmitters and the detectors. An initiation signal for initiating operation of the detector is wirelessly sent from the transmitter to the detector, using a low frequency, and the pressure and temperature data detected by the detector are wirelessly sent to the monitor, using a radio frequency. A vehicle identification code differentiating the vehicle from other vehicles may be included in the initiation signal to avoid confusion with signals wirelessly sent from other vehicles. The detector is operated only when the tire condition data from that detector are required to minimize power consumption in the detector.

Claims

1. A system for monitoring tire conditions including pressure in a tire of a vehicle, the system comprising:

a detector for detecting tire conditions including pressure in the tire, the detector being installed in each tire of the vehicle, the detector wirelessly transmitting detected data concerning the tire conditions;

a transmitter for wirelessly transmitting an initiation signal for initiating detection of the tire conditions to the detector, the transmitter being installed in the vicinity of each tire; and

a monitor for sending the initiation signal to the transmitter and for receiving the detected data from the detector, the monitor informing a driver of the vehicle of detected tire conditions.

2. The monitoring system as in claim 1, wherein:

the initiation signal includes a vehicle identification code identifying this vehicle on which the monitoring system is installed; and

the detected data are transmitted only when the vehicle identification code included in the initiation signal coincides with the vehicle identification code memorized in the detector.

3. The monitoring system as in claim 2, wherein:

the initiation signal further includes a detector identification code identifying the detector installed in each tire taking respective positions; and

the detected data are transmitted from the detector only when both the vehicle identification code and the detector identification code included in the initiation signal coincide with the vehicle identification code and the detector identification code memorized in the detector.

4. The monitoring system as in claim 3, wherein:

the monitoring system further includes means for finding the detector identification code memorized in each detector installed in each tire taking respective positions by sequentially transmitting detector identification codes to the detector and by determining that the detector identification code memorized in the detector is the same as the detector identification code transmitted to the detector if the detected data concerning the tire conditions are transmitted from the detector.

5. The monitoring system as in claim 1, wherein:

the detector starts detection of the tire conditions upon receipt of the initiation signal; and

the detection of the tire conditions is terminated after the detected data concerning the tire conditions are transmitted to the monitor.

6. The monitoring system as in claim 5, wherein:

the initiation signal transmitted from the transmitter to the detector is a low frequency signal in a long wave band;

the detector includes a power source circuit that rectifies the initiation signal to generate a power source voltage for operating the detector; and

the detector starts its operation upon generation of the power source voltage.

7. The monitoring system as in claim 5, wherein:

the monitor includes a single receiver that receives the detected data from all of the detectors.

8. The monitoring system as in claim 7, wherein:

the detector transmits the detected data using radio frequency signals in either a very high frequency band or a ultra high frequency band.

9. The monitoring system as in claim 5, wherein:

the transmitter includes means for receiving the detected data transmitted from the detector and for sending the detected data to the monitor.

10. The monitoring system as in claim 9, wherein:

the detector and the transmitter include respective antennas that transmit and receive low frequency signals in a long wave band;

the initiation signal is transmitted from the transmitter to the detector and the detected data are transmitted from the detector to the transmitter, both using the low frequency signals; and

the detector includes a power source circuit that rectifies the initiation signal to formulate a power source voltage, and the detector starts its operation upon formulation of the power source voltage.

11. The monitoring system as in claim 5, wherein:

the initiation signal is sequentially sent to detectors to initiate operation thereof one by one, and the detected data are sequentially transmitted from the detectors to the monitor to avoid data confusion in the monitor.

12. The monitoring system as in claim 11, wherein:

the initiation signal is sent again to the detector which has been unable to transmit the detected data.

13. The monitoring system as in claim 5, wherein:

the initiation signal is simultaneously sent to all the detectors, and the detectors are adapted to transmit detected data at respectively different timing to avoid data confusion in the monitor.

14. The monitoring system as in claim 9, wherein:

the initiation signal is simultaneously transmitted from the transmitters to the corresponding detectors, and the detected data are simultaneously transmitted from the detectors to the corresponding transmitters.

15. The monitoring system as in claim 13, wherein:

the initiation signal is transmitted again to the detector which has been unable to transmit the detected data.

16. The monitoring system as in claim 5, wherein:

the initiation signal includes a detector identification code identifying the detector installed in each tire taking respective positions; and

the detected data are transmitted from the detector when the detector identification code included in the initiation signal coincides with the detector identification code memorized in the detector.