Magnetic sensor

• US 6,587,048 B1
• Filed: 08/26/2000
• Issued: 07/01/2003
• Est. Priority Date: 08/26/1999
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Bomya, Timothy J.
• Primary Examiner(s): LA, ANH V
• Application Number:
  US09/648,606
• Time in Patent Office: 1,039 Days
• Field of Search: 340/573.1, 340/540, 340/547, 340/436, 340/435, 340/438, 340/545.1, 340/545.2, 340/430, 340/551, 180/274, 180/282, 280/735, 280/734, 307/10.1
• US Class Current: 340/573.1
• CPC Class Codes: B60R 2021/01122 Prevention of malfunction
• 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 coil operatively coupled to a ferromagnetic element of a vehicle body, at least one oscillating signal operatively connected to the at least one coil, a circuit for sensing a measure responsive to a self-inductance of the at least one coil, and a circuit for discriminating a crash from the measure.

Claims

1. A magnetic sensor, comprising:

a. at least one coil operatively coupled to a ferromagnetic element of a vehicle body;

b. at least one signal operatively connected to said at least one coil, wherein said at least one signal comprises an oscillating signal;

c. a means for sensing a measure corresponding to a self-inductance of said at least one coil; and

d. a means for discriminating a crash from said measure.

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

3. A magnetic sensor as recited in claim 1, wherein at least one said at last one 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.

4. A magnetic sensor as recited in claim 3, wherein at least one said at least one coil is around at least one said vehicle body element.

5. A magnetic sensor as recited in claim 1, wherein at least one said at least one 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.

6. A magnetic sensor as recited in claim 5, wherein at least one said at least one coil is around at least one said vehicle body element.

7. A magnetic sensor as recited in claim 2, wherein said plurality of coils arc located at distinct locations of said vehicle body.

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

9. A magnetic sensor as recited in claim 2, wherein at least two of said plurality of coils have common phasing.

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

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

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

13. 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 with a coil, wherein said first magnetic flux is oscillating and said first magnetic flux is responsive to a crash of said vehicle;

b. generating a signal corresponding to a self-inductance of said coil; and

c. discriminating said vehicle crash responsive to said signal.

14. A method of sensing a vehicle crash as recited in claim 13, wherein said magnetic flux is generated with at least one coil, further comprising determining a measure of power applied to said at least one coil and determining a proximity of an object to said vehicle body from said measure of power.

15. A method of sensing a vehicle crash as recited in claim 13, wherein the operation of generating a first magnetic flux is responsive to a temperature proximate to said first location.

16. A method of sensing a vehicle crash recited in claim 13, further comprising controlling an actuation of a safety restraint system responsive to the operation of discriminating said vehicle crash.

17. 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 with at least one coil, wherein said first magnetic flux is oscillating said first magnetic flux is responsive to a crash of said vehicle, said first location comprises a plurality of distinct first locations and at least one coil comprises a plurality of said coils;

b. generating a signal corresponding to a self-inductance of said at least one coil;

c. discriminating said vehicle crash responsive to said signal;

d. determining a measure of power applied to said at least one coil and determining a proximity of an object to said vehicle body from said measure of power; and

e. determining a plurality of measures of power applied to a respective plurality of said plurality of coils and estimating a direction of said proximate object from said plurality of measures of power.

18. A method of sensing a vehicle crash as recited in claim 17, wherein the operation of generating a first magnetic flux is responsive to a temperature proximate to said first location.

19. A method of sensing a vehicle crash as recited in claim 17, further comprising controlling an actuation of a safety restraint system responsive to the operation of discriminating said vehicle crash.