Magnetic sensor

• US 6,777,927 B1
• Filed: 08/26/2000
• Issued: 08/17/2004
• Est. Priority Date: 08/26/1999
• Status: Expired due to Fees

• Current Assignee: TK Holdings Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Bomya, Timothy J.
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): KINDER, DARRELL D
• Application Number:
  US09/649,416
• Time in Patent Office: 1,452 Days
• Field of Search: 324/207.13, 324/207.2, 324/251, 324/228, 324/207.16, 324/207.17, 738/626.9, 340/540, 340/547, 340/573.1, 340/436, 307/10.1, 280/735
• US Class Current: 324/207.17
• CPC Class Codes: B60R 2021/01027 Safing sensors
• CPC Class Codes: B60R 21/0134 responsive to imminent contact with an obstacle , e.g. using radar systems
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558

Abstract

A magnetic sensor comprises at least one first coil and at least one magnetic sensing element, operatively connected to respective first and second locations of a body of a vehicle and to a ferromagnetic element of the body. The first and second locations are distinct from one another and are in magnetic communication through a first portion of the vehicle and through a second portion of the vehicle, wherein the first portion of the vehicle comprises a portion of the body that is susceptible to deformation by a crash, and the first portion is distinct from the second portion. At least one signal is applied to the at least one first coil, and the at least one magnetic sensing element generates a second signal responsive thereto, from which a crash is discriminated.

Claims

1. A magnetic sensor, comprising:

a. at least one first coil at an associated at least one first location of a body of a vehicle, wherein said at least one first coil is operatively coupled to a ferromagnetic element of a vehicle body;

b. at least one magnetic sensing element operatively connected to at least one second location of said body of said vehicle, wherein said at least one first and at least one second locations are in magnetic communication through a first portion of said vehicle and through a second portion of said vehicle, said first portion of said vehicle comprises a portion of said body that is susceptible to deformation by a crash, and said first portion is distinct from said second portion;

c. at least one first signal operatively connected to said at least one first coil;

d. a means for sensing at least one second signal from said at least one magnetic sensing element, wherein said at least one second signal is responsive to a coupling of a magnetic field through said first portion of said vehicle, said magnetic field is generated by said at least one first coil responsive to said at least one first signal, and said magnetic field is responsive to said deformation of said first portion of vehicle by said crash; and

e. a means for discriminating a crash from said at least one second signal.

2. A magnetic sensor as recited in claim 1, wherein said at least one first signal is an oscillating signal.

3. A magnetic sensor as recited in claim 1, wherein said means for discriminating a crash comprises a means for comparing said second signal with a threshold.

4. A magnetic sensor as recited in claim 1, wherein said at least one first coil comprises a plurality of first coils.

5. A magnetic sensor as recited in claim 4, wherein said at least one first signal comprises a plurality of first oscillating Signals, one of said plurality of first oscillating signals has a first phase and is applied to one of said plurality of first coils, and another of said plurality of first oscillating signals has a second phase and is applied to another of said plurality of first coils.

6. A magnetic sensor as recited in claim 4, wherein said plurality of coils are located at distinct locations of said vehicle body.

7. A magnetic sensor as recited in claim 6, wherein said plurality of coils are associated with a same door.

8. A magnetic sensor as recited in claim 4, wherein at least two of said plurality of coils have common phasing.

9. A magnetic sensor as recited claim 1, wherein at least one said at least one first coil is proximate to a vehicle body element selected from a door hinge or a mounting bolt thereof, a door lock or latch mechanism or a mounting bolt thereof, a striker of a door lock or latch mechanism or a mounting bolt thereof, a door reinforcing element, and an end wall of a door.

10. A magnetic sensor as recited in claim 9, wherein at least one said at least one first coil is around at least one said vehicle body element.

11. A magnetic sensor as recited in claim 1, wherein at least one said at least one first coil is proximate to a vehicle body element selected from a door, a door opening, a portion of a side view mirror housing and a window opening.

12. A magnetic sensor as recited in claim 11, wherein at least one said at least one first coil is around at least one said vehicle body element.

13. A magnetic sensor as recited in claim 1, wherein at least one said at least one magnetic sensing element is proximate to a vehicle body element selected from a door, a door opening, a portion of aside view mirror housing and a window opening.

14. A magnetic sensor as recited in claim 13, wherein at least one said at least one magnetic sensing element comprises at least one coil around at least one said vehicle body element.

15. A magnetic sensor as recited in claim 1, wherein said at least one magnetic sensing element comprises a plurality of magnetic sensing elements at distinct second locations.

16. A magnetic sensor as recited in claim 1, wherein at least one said at least one first coil comprises a coil around one of either a lower door hinge or an upper door hinge, and said at least one magnetic sensing element comprises a second coil around the other of either said upper door hinge or said lower door hinge.

17. A magnetic sensor as recited in claim 1, wherein said first signal comprises an oscillating signal and a frequency of said first signal is modulated.

18. A magnetic sensor as recited in claim 1, further comprising a first circuit operatively connected to said at least one first coil, wherein said at least one first signal is applied to said at least one first coil by said first circuit and said first circuit is adapted so that said at least one first coil is substantially in resonance by said at least one first signal.

19. A magnetic sensor as recited in claim 1, further comprising a first circuit operatively connected to said at least one first coil, wherein said at least one first signal is applied to said at least one first coil by said first circuit, and said first circuit determines a measure of power delivered to said at least one first coil from said at least one first signal.

20. A magnetic sensor as recited in claim 1, wherein said means for sensing at least one signal comprises a second circuit that is in resonance with said magnetic sensing element.

21. A magnetic sensor as recited in claim 1, further comprising at least one second magnetic sensing element proximate to said at least one first coil for testing the operativeness of said at least one first coil.

22. A magnetic sensor as recited in claim 1, wherein said at least one second location is distinct from said at least one first location and said first and second portions of said vehicle constitute a closed magnetic path.

23. A magnetic sensor as recited in claim 1, wherein at least one said at least one magnetic sensing element is proximate to a vehicle body element selected from a door hinge or a mounting bolt thereof, a door lock or latch mechanism or a mounting bolt thereof, a striker of a door lock or latch mechanism or a mounting bolt thereof, a door reinforcing element, and an end wall of a door.

24. A magnetic sensor as recited iiclaim 23, wherein at least one said at least one magnetic sensing element comprises at least one coil around at least one said vehicle body clement.

25. A magnetic sensor as recited in claim 1, wherein said at least one magnetic sensing element is selected from at least one coil and at least one Hall effect sensor.

26. A magnetic sensor as recited in claim 1, wherein sad at least one magnetic sensing element comprises a plurality of magnetic sensing elements.

27. A method of sensing a vehicle crash, comprising:

a. generating a first magnetic flux at a first location of a vehicle in a ferromagnetic element of a vehicle body, wherein said first magnetic flux is responsive to a crash of said vehicle;

b. conducting said first magnetic flux between said first location and a second location of said vehicle along a first path, wherein said first path is through a body part of said vehicle;

c. conducting said first magnetic flux between said first location and said second location along a second path, wherein said first and second paths form a closed path, and a magnetic reluctance along at least one of said first path and said second path is responsive to said vehicle crash;

d. sensing at least a portion of said first magnetic flux at said second location;

e. generating a signal responsive to said magnetic flux sensed at said second location, wherein said magnetic flux sensed at said second location is responsive to said magnetic reluctance, and said magnetic reluctance is responsive to said vehicle crash; and

f. discriminating said vehicle crash responsive to said signal.

28. A method of sensing a vehicle crash as recited in claim 27, wherein said first magnetic flux is oscillating.

29. A method of sensing a vehicle crash as recited in claim 27, wherein said magnetic flux is generated with at least one first coil, further comprising determining a measure of power applied to said at least one first coil and determining a proximity of an object to said vehicle body from said measure of power.

30. A method of sensing a vehicle crash as recited in claim 29, wherein said first location comprises a plurality of distinct first locations and said magnetic flux is generated with a plurality of first coils, further comprising determining a plurality of measures of power applied to a respective plurality of said plurality of first coils and estimating a direction of said proximate object from said plurality of measures of power.

31. A method of sensing a vehicle crash as recited in claim 27, wherein the operation of generating a first magnetic flux is responsive to a temperature proximate to said first location.

32. A method of sensing a vehicle crash as recited in claim 27, wherein said second location comprises a plurality of second locations, further comprising comparing said signal with a reference signal and discriminating said vehicle crash responsive to said operation of comparing, wherein said operation of comparing comprises comparing waveform shapes of said signal and said reference signal and said reference signal is responsive to a first signal by which said magnetic flux is generated.

33. A method of sensing a vehicle crash as recited in claim 27, wherein said operation of discriminating said vehicle crash comprises comparing a phase of said signal with a phase of a first signal by which said magnetic flux is generated.

34. A method of sensing a vehicle crash as recited in claim 33, further comprising controlling an actuation of a safety restraint system responsive to said operation of discriminating said vehicle crash.

35. A method of sensing a vehicle crash as recited in claim 27, further comprising synchronously demodulating said signal so as to form a second signal, DC coupling said second signal so as to form a DC coupled second signal, and extracting a first component of said signal from said DC coupled second signal.

36. A method of sensing a vehicle crash as recited in claim 35, wherein said operation of discriminating said vehicle crash comprises comparing a magnitude of said first component of said signal with a second threshold.

37. A method of sensing a vehicle crash as recited in claim 35, wherein said operation of discriminating said vehicle crash comprises comparing a rate of change to of said first component of said signal with a third threshold.

38. A method of sensing a vehicle crash as recited in claim 35, further comprising AC coupling and amplifying said second signal so as to form and AC coupled second signal, and extracting a second component of said signal from said AC coupled second signal.

39. A method of sensing a vehicle crash as recited in claim 38, wherein said operation of discriminating said vehicle crash comprises:

a. comparing a rate of change of said second component of said signal with a first threshold;

b. comparing a magnitude of said first component of said signal with a second threshold;

c. comparing a rate of change of said first component of said signal with a third threshold; and

d. deploying a safety restraint system if a first condition is met and then a second condition is met, wherein said first condition is met if said rate of change of said second component of said signal exceeds said first threshold, and said second condition is met if said magnitude of said first component of said signal exceeds said second threshold and said rate of change of sad first component of said signal exceeds said third threshold.

40. A method of sensing a vehicle crash as recited in claim 27, further comprising synchronously demodulating said signal so as to form a second signal, AC coupling and amplifying said second signal so as to form and AC coupled second signal, and extracting a second component of said signal from said AC coupled second signal.

41. A method of sensing a vehicle crash as recited in claim 40, wherein said operation of discriminating said vehicle crash comprises comparing a rate of change of said second component of said signal with a first threshold.