Method and apparatus for sensing tire pressure

• US 20030201879A1
• Filed: 04/30/2002
• Published: 10/30/2003
• Est. Priority Date: 04/30/2002
• Status: Active Grant

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Munch, Carl A., DeZorzi, Timothy
• Granted Patent: US 6,914,523 B2
• Time in Patent Office: Days
• US Class Current: 340/442
• 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 23/042 cooperating with wheel hub mounted speed sensors
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00

Abstract

An apparatus for sensing pressure in vehicle tires includes an interrogator (102) for providing a tire pressure interrogation signal, and a tire pressure monitor (70) for sensing pressure within a first tire (24) of the vehicle (20) and providing an actual tire pressure signal. A first wheel speed sensor (42) associated with the first tire (24) provides a reference wheel speed signal upon movement of the vehicle (20). A second wheel speed sensor (40) associated with a second tire (22) of the vehicle (20) provides a wheel speed signal upon movement of the vehicle. A controller (60) activates the interrogator (102), monitors the actual tire pressure signal, and correlates the reference wheel speed signal with the wheel speed signal from the second wheel speed sensor (40) for determining a tire pressure value of the second tire (22).

Claims

1. An apparatus for sensing pressure in vehicle tires comprising:

an interrogator, when actuated, providing an interrogation signal;

a tire pressure monitor for sensing pressure within a first tire of the vehicle in response to the interrogation signal and providing an actual tire pressure signal;

a first wheel speed sensor associated with the first tire for providing a reference wheel speed signal upon movement of the vehicle;

a second wheel speed sensor associated with a second tire of the vehicle and providing a wheel speed signal upon movement of the vehicle; and

a controller connected to said interrogator for actuating said interrogator, monitoring the actual tire pressure signal, and correlating the reference wheel speed signal with the wheel speed signal from the second wheel speed sensor for determining a tire pressure value of the second tire.

2. The apparatus of claim 1 wherein said tire pressure monitor is mounted internal to the first tire.

3. The apparatus of claim 2 wherein said tire pressure monitor includes an RF transmitter for transmitting the actual tire pressure signal as an RF signal.

4. The apparatus of claim 3 wherein said interrogator is mounted adjacent the first tire, said tire pressure monitor including means for responding to said interrogation signal so as to take a tire pressure measurement and transmit the actual tire pressure RF signal in response thereto.

5. The apparatus of claim 4 wherein said interrogation signal is an LF signal.

6. The apparatus of claim 3 wherein said controller includes a receiver for receiving the RF tire pressure signal.

7. The apparatus of claim 6 wherein said receiver includes means for receiving a remote convenience function request and said controller includes means for responding to the remote convenience function request.

8. The apparatus of claim 1 further including display means and wherein said controller further includes means for comparing the determined tire pressure value of the second tire against predetermined limits, said controller activating said display means for notifying a vehicle operator when said determined tire pressure value of the second tire is outside of said limits.

9. The apparatus of claim 1 wherein said first tire and said second tire are located on the same side of the vehicle.

10. The apparatus of claim 1 wherein said first wheel speed sensor and said second wheel speed sensor include variable reluctance sensors.

11. The apparatus of claim 1 wherein said tire pressure monitor is mounted internal to the first tire and includes an RF transmitter for transmitting the actual tire pressure signal as an RF signal, and wherein said interrogator is mounted adjacent the first tire for providing an LF interrogation signal to said tire pressure monitor, said tire pressure monitor including means for responding to said LF interrogation signal so as to take a tire pressure measurement and transmit the actual tire pressure RF signal in response thereto.

12. The apparatus of claim 11 wherein said first wheel speed sensor includes variable reluctance sensor and wherein said variable reluctance sensor functions as both a transmitting antenna for the LF interrogation signal and a receiving antenna for the RF tire pressure signal.

13. The apparatus of claim 12 wherein said controller includes multiplexing means for multiplexing the LF interrogation signal and the RF tire pressure signal to process the signals separately.

14. The apparatus of claim 1 further including a third wheel speed sensor associated with a third tire of the vehicle and providing a wheel speed signal upon movement of the vehicle and a forth wheel speed sensor associated with a forth tire of the vehicle and providing a wheel speed signal upon movement of the vehicle, said controller correlating the reference wheel speed signal with the wheel speed signals from the third and forth wheel speed sensors for determining tire pressure values of the third and forth tires, respectively.

15. The apparatus of claim 14 further including display means and wherein said controller further includes means for comparing the determined tire pressure value of the second, third and forth tires against predetermined limits, said controller activating said display means for notifying a vehicle operator when any of said determined tire pressure values are outside of said limits.

16. The apparatus of claim 14 wherein said display means includes means for displaying information about the vehicle'"'"'s four tires separately and wherein said controller includes means for controlling said display to identify which tires are outside of said limits.

17. The apparatus of claim 14 wherein said tire pressure monitor is mounted internal to the first tire and includes an RF transmitter for transmitting the actual tire pressure signal as an RF signal, and wherein said interrogator is mounted adjacent the first, second, third, and forth tires of the vehicle for providing LF interrogation signals, said tire pressure monitor including means for responding to said LF interrogation signal so as to take a tire pressure measurement and transmit the actual tire pressure RF signal in response thereto, said controller including means for sequentially activating said interrogator to separately provide LF interrogation signals to the four tires and monitoring from which of the tires said RF tire pressure signal is received.

18. The apparatus of claim 17 wherein said separate activation of said interrogator for the four tires occurs each time the vehicle is started.

19. The apparatus of claim 17 wherein said first, second, third, and forth wheel speed sensors are variable reluctance sensors, each functioning as both a transmitting antenna for its associated LF interrogation signal and a receiving antenna for the RF tire pressure signal, said controller including multiplexing means for multiplexing the LF interrogation signals and the RF tire pressure signal so as to process the signals separately.

20. The apparatus of claim 14 further including an antilock braking means for monitoring the wheel speed sensors associated with the first, second, third, and forth tires and controlling a braking system in response thereto.

21. The apparatus of claim 1 wherein said apparatus further includes display means for displaying tire pressure information and wherein said controller includes fault detection means for determining if a fault condition exists in the tire pressure monitor and the first or second wheel speed sensors and activating said display means to notify a vehicle operator when a fault condition is detected.

22. The apparatus of claim 21 wherein said controller includes means for establishing a default pressure correlation value for the reference wheel speed signal when a fault condition is detected with the tire pressure monitor.

23. The apparatus of claim 1 wherein the first and second wheel speed sensors each provide a predetermined number of pulse signals for each rotation of their associated tire.

24. The apparatus of claim 23 wherein said controller correlates the reference wheel speed signal with the wheel speed signal from the second wheel speed sensor based on the count of the pulse signals from both of the wheel speed sensors.

25. The apparatus of claim 23 wherein said controller correlates the reference wheel speed signal with the wheel speed signal from the second wheel speed sensor based on the counts per unit of time of the pulse signals from both of the wheel speed sensors.

26. An apparatus for sensing pressure in vehicle tires comprising:

means for providing an interrogation signal;

means for sensing pressure within one of the tires in response to the interrogation signal;

means for sensing wheel speeds of the vehicle tires and providing wheel speed signals, a wheel speed signal of the one tire in which pressure is sensed being a reference wheel speed signal; and

means for correlating the reference wheel speed signal with other of the wheel speed signals for determining tire pressure within associated tires.

27. The apparatus of claim 26 wherein said means for sensing pressure is mounted internal to the one tire and includes an RF transmitter for transmitting the sensed tire pressure as an RF signal.

28. The apparatus of claim 27 wherein said means for providing the interrogation signal is mounted adjacent the one tire for providing the interrogation signal to said means for sensing pressure, said means for sensing pressure including means for responding to said interrogation signal so as to take a tire pressure measurement and transmit the sensed RF tire pressure signal in response thereto.

29. The apparatus of claim 28 wherein said means for correlating includes a receiver for receiving the RF tire pressure signal.

30. The apparatus of claim 29 wherein said receiver includes means for receiving a remote convenience function request and said apparatus further includes means for responding to the remote convenience function request.

31. The apparatus of claim 26 further including display means and wherein said means for correlating further includes means for comparing the determined tire pressure value of each of the other tires against predetermined limits and activating said display means for notifying a vehicle operator when said determined tire pressure is outside of said limits.

32. The apparatus of claim 26 wherein said means for sensing pressure is mounted internal to the one tire and includes an RF transmitter for transmitting an actual tire pressure signal as an RF signal, said means for providing an interrogation signal is mounted adjacent the one tire and provides an LF interrogation signal to said means for sensing pressure, said means for sensing pressure including means for responding to said LF interrogation signal to take a tire pressure measurement and transmit the actual RF tire pressure signal in response thereto.

33. The apparatus of claim 26 further including an antilock braking means for monitoring the means for sensing wheel speeds and for controlling a braking system in response thereto.

34. The apparatus of claim 26 further including display means for displaying tire pressure information and fault detection means for determining if a fault condition exists, said fault detection means activating said display means to notify a vehicle operator when a fault condition is detected.

35. The apparatus of claim 26 wherein the wheel speed signals each provide a predetermined number of pulse signals for each rotation of their associated tire.

36. The apparatus of claim 35 wherein said means for correlating correlates based on the count of the pulse signals from of the wheel speed signals.

37. The apparatus of claim 35 wherein said means for correlating correlates based on the counts per unit of time of the pulse signals of the wheel speed signals.

38. An apparatus for sensing pressure in vehicle tires comprising:

wheel speed sensors for providing associated wheel speed sensor signals including a plurality of pulses for each revolution of an associated tire;

an interrogator for providing an interrogation signal;

a tire pressure monitor for, in response to an interrogation signal, sensing pressure in the tire and providing a pressure signal indicative of the sensed pressure;

first correlating means for correlating the sensed pressure with an associated wheel speed sensor signal to establish a reference wheel speed signal; and

second correlating means for correlating the reference wheel speed signal with signals from other of the wheel speed sensors for determining a pressure value of associated tires.

39. An apparatus for sensing pressure in tires on a vehicle having at least two wheel speed sensors, each wheel speed sensor providing an associated wheel speed signal indicative of wheel speed of its associated ti re, said apparatus comprising:

an interrogator for providing an interrogation signal;

a tire pressure monitor mounted within a tire having an associated one of said at least two wheel speed sensors for, in response to the interrogation signal, measuring tire pressure and providing a signal indicative of measured pressure; and

a controller for actuating said interrogator to provide the interrogation signal, monitoring the wheel speed signals from the at least two wheel speed sensors, establishing a reference wheel speed signal for the wheel speed sensor of the tire having said tire pressure monitor based on the measured pressure, and determining pressure in other tires having an associated wheel speed sensor by correlation with the reference wheel speed signal.

40. The apparatus of claim 39 wherein the at least two wheel speed sensors each provide a predetermined number of pulse signals for each rotation of their associated tire.

41. The apparatus of claim 40 wherein said controller correlates based on the count of the pulse signals from the at least two wheel speed sensors.

42. The apparatus of claim 40 wherein said controller correlates based on the counts per unit of time of the pulse signals from the at least two wheel speed sensors.

43. An apparatus for sensing tire pressure in vehicle tires comprising;

wheel speed sensors, at least two vehicle tires having an associated wheel speed sensor, each wheel speed sensor providing a signal having an electrical characteristic indicative of pressure within its associated tire when the vehicle is moving;

an interrogator for, when actuated, providing an interrogation signal;

a tire pressure monitor located within one tire of the vehicle having an associated wheel speed sensor, said tire pressure monitor, in response to the interrogation signal, measuring tire pressure and providing a signal indicative of actual tire pressure;

controller for actuating the interrogator, monitoring the signal indicative of actual tire pressure, and correlating the wheel speed sensor signal associated with the tire having the tire pressure monitor with the wheel speed signals from the other tires having associated wheel speed sensors for determining pressure in such other tires.

44. The apparatus of claim 43 wherein the wheel speed sensors each provide a predetermined number of pulse signals for each rotation of their associated tire.

45. The apparatus of claim 44 wherein said controller correlates based on the count of the pulse signals from the at least two wheel speed sensors.

46. The apparatus of claim 44 wherein said controller correlates based on the counts per unit of time of the pulse signals from the at least two wheel speed sensors.

47. An apparatus for sensing pressure in vehicle tires comprising:

means for sensing pressure within one of the tires;

means for detecting in which tire the pressure sensor is located;

means for sensing wheel speeds of the vehicle tires and providing wheel speed signals, a wheel speed signal of the one tire in which the means for sensing pressure is detected being a reference wheel speed signal; and

means for correlating the reference wheel speed signal with other of the wheel speed signals for determining tire pressure within associated tires.

48. A method for sensing pressure in vehicle tires comprising the steps of:

interrogating a pressure measurement with a remote signal;

sensing pressure within a first tire of the vehicle in response to the interrogation and providing an actual tire pressure signal;

providing a reference wheel speed signal for the first tire of the vehicle upon movement of the vehicle;

providing a wheel speed signal for a second tire of the vehicle upon movement of the vehicle;

monitoring the actual tire pressure signal; and

correlating the reference wheel speed signal with the wheel speed signal from the second tire and determining a tire pressure value of the second tire in response to the correlating.

49. The method of claim 48 further comprising the step of transmitting the actual tire pressure signal as an RF signal.

50. The method of claim 48 wherein the step of providing a reference wheel speed signal for the first tire of the vehicle includes providing a plurality of pulse signals for each rotation of the first tire and wherein the step of providing the wheel speed signal for the second tire of the vehicle upon movement of the vehicle includes providing a plurality of pulse signals for each rotation of the second tire.

51. The apparatus of claim 50 wherein said step of correlating is based on the count of the pulse signals from the reference wheel speed signal and the wheel speed signal fro the second tire.

52. The apparatus of claim 50 wherein said step of correlating is based on the counts per unit of time of the pulse signals from the at reference wheel speed signal and the wheel speed signal fro the second tire.

53. The method of claim 50 further including the step of notifying a vehicle operator when said determined tire pressure value is outside of predetermined limits.

54. The method of claim 50 wherein the step of interrogating includes transmitting a LF signal.

55. A method for sensing pressure in vehicle tires comprising the steps of:

interrogating a pressure measurement with a remote signal;

sensing pressure within one of the tires in response to the interrogating;

sensing wheel speeds of the vehicle tires and providing wheel speed signals, a wheel speed signal for the one tire in which pressure is sensed being a reference wheel speed signal; and

correlating the reference wheel speed signal with other of the wheel speed signals for determining tire pressure within associated tires.

56. A method for sensing pressure in vehicle tires comprising the steps of:

providing associated wheel speed sensor signals including a plurality of pulses for each revolution of an associated tire;

interrogating a tire pressure measurement;

sensing pressure in one of the tires in response to the interrogating and providing a pressure signal indicative of the sensed pressure;

correlating the sensed pressure with an associated wheel speed sensor signal to establish a reference wheel speed signal; and

correlating the reference wheel speed signal with signals from other of the wheel speed sensors for determining a pressure value of associated tires.

57. A method for sensing pressure in tires on a vehicle having at least two wheel speed sensors, each wheel speed sensor providing an associated wheel speed signal indicative of wheel speed of its associated tire, said method comprising the steps of:

interrogating a tire pressure measurement;

measuring tire pressure within a tire having an associated one of the at least two wheels speed sensors in response to the interrogating and providing a signal indicative of measured pressure;

monitoring the wheel speed signals from the at least two wheel speed sensors;

establishing a reference wheel speed signal for the wheel speed sensor of the tire having said tire pressure monitor based on the measured pressure; and

determining pressure in other tires having an associated wheel speed sensor by correlation with the reference wheel speed signal.

58. A method for sensing pressure in vehicle tires comprising the steps of:

sensing pressure within one of the tires;

detecting in which tire the pressure sensor is located;

sensing wheel speeds of the vehicle tires and providing wheel speed signals, a wheel speed signal of the one tire in which the means for sensing pressure is detected being a reference wheel speed signal; and

correlating the reference wheel speed signal with other of the wheel speed signals for determining tire pressure within associated tires.