Magnetic crash sensor

• US 7,514,917 B2
• Filed: 09/11/2006
• Issued: 04/07/2009
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Smith, Richard W., Baal, James D., Cech, Leonard S., Watson, W. Todd, Bauer, Scott E., Merrick, William, Bomya, Timothy J.
• Primary Examiner(s): WHITTINGTON, KENNETH
• Application Number:
  US11/530,492
• Publication Number:
  US 20090001976A1
• Time in Patent Office: 939 Days
• Field of Search: 324/209, 324/228, 324/233, 324/239, 324/240, 324/207.16, 324/207.17, 324326-329, 701 45- 48, 701/1, 701/36, 280/735, 180/232, 738/626.9
• US Class Current: 324/228
• CPC Class Codes: B60R 2021/0006 Lateral collision
• 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 time-varying signal is applied to at least one coil in magnetic communication with at least a portion of a vehicle susceptible to deformation responsive to a crash. A sense resistor in series with the at least one coil provides for detecting a current therethrough responsive to a voltage thereacross. The current is responsive to a magnetic condition affecting the magnetic field generated by the at least one coil, responsive to the reluctance of a magnetic circuit with which the at least one coil is in magnetic communication, and responsive to associated eddy currents in proximal conductive elements, responsive to the magnetic field generated by the at least one coil.

Claims

1. A magnetic crash sensor, comprising:

a. at least one coil in magnetic communication with at least a portion of a vehicle, wherein said portion of said vehicle is susceptible to deformation responsive to a crash;

b. a signal source operatively associated with said at least one coil, wherein said signal source provides for generating a first time-varying signal, said first time-varying signal comprises at least one pulse, and said first time-varying signal is operatively coupled to said at least one coil so as to cause said at least one coil to generate a magnetic field; and

c. at last one circuit, wherein said at least one circuit comprises at least one sense resistor in series with said at least one coil, said current through said at least one coil and through said at least one sense resistor is responsive to said first signal, said first signal comprises a time-varying voltage applied by said signal source, said current through said at least one coil and through said at least one sense resistor is also responsive to a magnetic condition of said at least one coil, said magnetic condition is responsive to said magnetic communication of said at least one coil with said portion of said vehicle, said at least one circuit generates a second signal responsive to a voltage across said at least one sense resistor, and said at least one circuit is adapted to charge said at least one coil through said at least one sense resistor with said pulse when said pulse is activated, and said at least one circuit is adapted to discharge said at least one coil through a second resistor after said at least one pulse is deactivated.

2. A magnetic crash sensor as recited in claim 1, wherein said at least one pulse is mono-polar, and said at least one circuit comprises a diode in series with said second resistor, wherein said diode is reverse biased by said at least one pulse.

3. A magnetic crash sensor as recited in claim 1, wherein said at least one pulse is bi-polar, and said at least one circuit comprises a switch in series with said second resistor, wherein said switch is turned off when said at least one pulse is activated, and said switch is turned off when said at least one pulse is deactivated.

4. A magnetic crash sensor as recited in claim 1, wherein said at least one pulse is mono-polar, said at least one circuit comprises a diode in series with said second resistor, wherein said diode is reverse biased by said at least one pulse, and said at least one circuit comprises an H-switch, wherein said H-switch is adapted to control a direction of current through said at least one coil, and said H-switch is adapted to periodically reverse a flow of current through said at least one coil responsive to said at least one pulse.