Data logging tire monitor with condition predictive capabilities and integrity checking

• US 5,559,484 A
• Filed: 02/07/1994
• Issued: 09/24/1996
• Est. Priority Date: 05/14/1991
• Status: Expired due to Term

• Current Assignee: Bendix Commercial Vehicle Systems LLC (Estate of Heinz Hermann Thiele)
• Original Assignee: EPIC Technologies Incorporated
• Inventors: Nowicki, Donald V., Munroe, Christopher A.
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US08/192,672
• Time in Patent Office: 960 Days
• Field of Search: 340/447, 340/445, 340/442, 73/146.4, 73/146.5, 200/61.25, 200/61.22
• US Class Current: 340/447
• CPC Class Codes: A44B 15/005 Fobs
• 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 23/0411 Piezoelectric generators
• CPC Class Codes: B60C 23/0433 Radio signals
• CPC Class Codes: G04B 47/005 combined with a key
• CPC Class Codes: G07C 1/30 Parking meters registering or indicating waiting time of vehicles by means driven by the vehicle G07C5/02; coin-freed parking meters G07F17/24
• CPC Class Codes: G07C 5/008 communicating information to a remotely located station transmission systems for measured values G08C
• CPC Class Codes: G08B 21/24 Reminder alarms, e.g. anti-loss alarms

Abstract

A device is provided for sensing a condition of a non-rotating pneumatic tire preferably of the type used on an automobile wherein the tire is mounted on a tire rim. The device comprises a housing, a band for mounting the housing to the tire rim, a sensor for monitoring the condition within the tire, circuitry operatively connected to the sensor for generating radio signals indicative of the tire condition, a power supply operatively connected to the circuitry, an externally controlled switch, and a receiver for receiving the radio signals. The externally controlled switch is manually or electromagnetically operable to cause the condition sensor to generate radio signals when the pneumatic tire is stationary. A method of mathematically cross-linking data and identification information is provided to ensure data integrity. Also, the system includes a data logging capability for storing time series tire condition information for use as a historical log of tire use. Predictive capabilities retrieve manufacturer'"'"'s specifications stored in a memory for comparison against real time use data to predict or otherwise anticipate possible hazardous conditions or tire life expectancy.

Claims

1. A method of monitoring the condition of a non-rotating pneumatic tire for use with a monitoring system having a transmitter device including a power supply, a condition sensor, a microcontroller, a radio signal generating circuit, and a receiver device for receiving radio siqnals, the method comprising the steps of:

disposing the transmitter device within the pneumatic tire;

sensing a vibration of said pneumatic tire while the tire is stationary;

enabling said microcontroller by connection of the microcontroller to the power supply through a first switch responsive to said sensed vibration by intermittently closing contacts of a vibration switch on the transmitter device and operating said first switch when said intermittently closing contacts of said vibration switch are closed;

sensing said pneumatic tire condition with said condition sensor;

controlling the radio signal generating circuit with the enabled microcontroller to generate a radio signal representative of said sensed pneumatic tire condition; and

,

receiving the generated radio signal with the receiver device;

wherein said step of operating said first switch when said intermittently closing contacts of said vibration switch are closed includes the steps of;

providing a buffering circuit in said first switch, the buffering circuit having a characteristic time constant;

connecting said microcontroller to the power supply through said first switch responsive to i) said intermittently closing contacts being closed and ii) said buffering circuit being in a first state; and

,

maintaining said microcontroller connected to said power supply while said buffering circuit remains in said first state for at least a time period corresponding to said buffering circuit characteristic time constant.

2. A method of monitoring the condition of a non-rotating pneumatic tire for use with a monitoring system having a transmitter device including a power supply, a condition sensor, a microcontroller, a radio signal generating circuit, and a receiver device for receiving radio signals, the method comprising the steps of:

disposing the transmitter device within the pneumatic tire;

sensing a vibration of said pneumatic tire while the tire is stationary;

enabling said microcontroller by connection of the microcontroller to the power supply through a first switch responsive to said sensed vibration by generating a first voltage signal in response to said sensed vibration and operating said first switch exclusively in response to said first voltage signal;

sensing said pneumatic tire condition with said condition sensor;

controlling the radio signal generating circuit with the enabled microcontroller to generate a radio signal representative of said sensed pneumatic tire condition; and

,

receiving the generated radio signal with the receiver device;

wherein said step of operating said first switch in response to said first voltage signal includes the steps of;

providing a buffering circuit in said first switch, the buffering circuit having a characteristic time constant;

providing an amplifier circuit amplifying said first voltage signal for direct use by said first switch;

connecting said microcontroller to the power supply through said first switch responsive to i) said amplified first voltage signal and ii) said buffering circuit being in a first state; and

,

maintaining said microcontroller connected to said power supply while said buffering circuit remains in said first state for at least a time period corresponding to said buffering circuit characteristic time constant.

3. A method of monitoring the condition of a non-rotating pneumatic tire for use with a monitoring system having a transmitter device including a power supply, a condition sensor, a microcontroller, a radio signal generating circuit, and a receiver device for receiving radio signals, the method comprising the steps of:

disposing the transmitter device within the pneumatic tire;

sensing an application of an external electromagnetic signal generated in close proximity to said pneumatic tire while the tire is stationary;

enabling said microcontroller by connecting the microcontroller to the power supply through a first switch responsive to said sensed external electromagnetic signal by;

providing a buffering circuit in said first switch, the buffering circuit having a characteristic time constant;

amplifying said sensed external electromagnetic signal to form an amplified first command signal for immediate and direct use by said first switch;

connecting said microcontroller to the power supply through said first switch responsive to i) said first command signal and ii) said buffering circuit being in a first state; and

,

maintaining said microcontroller connected to said power supply while said buffering circuit remains in said first state for at least a time period corresponding to said buffering circuit characteristic time constant;

sensing said pneumatic tire condition with said condition sensor;

controlling the radio signal generating circuit with the enabled microcontroller to generate a radio signal representative of said sensed pneumatic tire condition; and

,

receiving the generated radio signal with the receiver device.

4. A method of monitoring the condition of a non-rotating pneumatic tire for use with a monitoring system having a transmitter device including a power supply, a condition sensor, a microcontroller, a radio signal generating circuit, and a receiver device for receiving radio signals, the method comprising the steps of:

disposing the transmitter device within the pneumatic tire;

sensing an application of an external electromagnetic signal generated in close proximity to said pneumatic tire while the tire is stationary;

enabling said microcontroller by connecting the microcontroller to the power supply through a first switch responsive to said sensed external electromagnetic signal by;

providing a buffering circuit in said first switch, the buffering circuit having a characteristic time constant;

connecting said microcontroller to the power supply through said first switch responsive to i) said sensed external electromagnetic signal and ii) said buffering circuit being in a first state; and

,

maintaining said microcontroller connected to said power supply while said buffering circuit remains in said first state for at least a time period corresponding to said buffering circuit characteristic time constant;

sensing said pneumatic tire condition with said condition sensor;

controlling the radio signal generating circuit with the enabled microcontroller to generate a radio signal representative of said sensed pneumatic tire condition; and

,

receiving the generated radio signal with the receiver device.

5. A tire condition monitoring apparatus for transmitting a tire condition signal to an operatively associated remote receiver device, the apparatus comprising:

a tire condition sensor for generating a tire condition signal;

a radio transmitter adapted to generate a radio signal for transmitting said tire condition signal to an operatively associated external remote receiver device;

a buffer circuit for selectively activating said radio transmitter for a preselected first time period in response to a first input signal; and

,

a first switch for selectively generating said first input signal responsive to a physical event at said tire condition monitoring apparatus, said first switch including a vibration switch having an inherent mechanical time constant, the vibration switch selectively generating said first input signal responsive to a vibration of the tire condition monitoring apparatus, said preselected first time period defining an electrical time constant of said buffer circuit substantially corresponding to said mechanical time constant of said vibration switch.

6. The tire condition monitoring apparatus according to claim 5 wherein said buffer circuit includes a solid state switch device for connecting the radio transmitter to a power source.

7. A method of remotely monitoring the condition of a tire comprising the steps of:

sensing a vibration of the tire with a vibration sensor having a first time constant and being disposed on said tire, the vibration sensor generating a first signal in response to said sensed vibration;

receiving said first signal into a buffer device to generate a buffer output signal for a first predetermined time period in response to said first signal, the first predetermined time period substantially corresponding to said first time constant;

with a tire condition sensor disposed in said tire, generating a tire condition signal; and

,

transmitting said tire condition signal to an operatively associated external remote receiver device in response to said buffer output signal from said buffer device.

8. A method of remotely monitoring the condition of a tire comprising the steps of:

sensing a vibration of said tire with a piezo unit disposed on said tire and having a first time constant, the piezo unit generating a piezo signal in response to said vibration;

receiving said piezo signal into a buffer device to generate a buffer output signal for a first predetermined time period in response to said piezo signal, said first predetermined time period substantially corresponding to said first time constant;

with a tire condition sensor disposed in said tire, generating a tire condition signal; and

,

transmitting said tire condition signal to an operatively associated external remote receiver device in response to said buffer output signal from said buffer device.