PROXIMITY DETECTION DEVICE FOR A MOTOR VEHICLE

• US 20110156890A1
• Filed: 06/05/2009
• Published: 06/30/2011
• Est. Priority Date: 06/06/2008
• Status: Active Grant

• Current Assignee: Faurecia Bloc Avant (Stellantis NV)
• Original Assignee: Faurecia Bloc Avant (Stellantis NV)
• Inventors: Aubry, Jean-Marcel
• Granted Patent: US 8,791,801 B2
• Time in Patent Office: Days
• US Class Current: 340/435
• CPC Class Codes: B60R 19/483 with obstacle sensors of electric or electronic type
• CPC Class Codes: G01V 3/088 operating with electric fields G01V3/082 takes precedence

Abstract

This device (4) allows the detection of the presence of an object in a detection zone by measuring a variation in capacitance brought about by the presence of the object. It includes an element (6) for emitting an electric field, an element (8) for receiving an electric field, and elements for measuring the coupling capacitance between the emission element (6) and the reception element (8), the emission element (6) emitting an electrical signal received by the reception element (8) so that a coupling capacitance of a predetermined value is established between the emission element (6) and the reception element (8) when no object is present in the detection zone, a variation in the coupling capacitance indicating the displacement of an object in the detection zone and the establishment of a capacitance of a different value from the predetermined value indicating the presence of a static object.

Claims

1. A device (4) for detecting the presence of an object in a proximity detection zone of a motor vehicle by measuring a variation in capacitance brought about by the presence of said object, characterized in that it comprises an element (6) for emitting an electric field, an element (8) for receiving an electric field arranged away from the emission element (6), and means for measuring the coupling capacitance between the emission element (6) and the reception element (8), the emission element (6) emitting an electrical signal that is then received by the reception device (8) such that a coupling capacitance of a predetermined value is established between the emission element (6) and the reception element (8) when no object is present in the detection zone, a variation in the coupling capacitance between the emission element (6) and the reception element (8) indicating the displacement of an object in the detection zone and the establishment of a capacitance of a different value from the predetermined value indicating the presence of a static object in the detection zone, an information device for the vehicle'"'"'s driver informing said driver of the presence of a moving or stationary obstacle around the motor vehicle.

2. The detection device according to claim 1, characterized in that it comprises a second emission element (16) and a second reception element (18) of an electrical field, said pair of elements (16, 18) being arranged to calibrate the detection device (4) relative to the ground and to perform complementary measurements with the first emission (6) and reception (8) elements.

3. The detection device according to claim 2, characterized in that the two pairs of emission and reception elements (6, 8, 16, 18) are arranged to operate at different frequencies.

4. The detection device according to claim 1, characterized in that the emission element (6, 16) emits a modulated signal, the reception element (8, 18) or control electronics (10) comprising a synchronous demodulation device making it possible to demodulate the signal received by the reception element (8, 18).

5. The detection according to claim 4, characterized in that it comprises a signal generator transmitting a square or sinusoidal signal to the emission element (6, 16) and a square signal to the demodulation device of the reception element (8, 18).

6. The detection device according to claim 2, characterized in that it comprises computation means arranged to determine the distance from the object relative to the motor vehicle as a function of the capacitance or the capacitance variation measured over the two pairs of emission and reception elements (6, 8, 16, 18).

7. A motor vehicle bumper (1) comprising a device (4) for detecting the presence of an object in a proximity detection zone of a motor vehicle on which the bumper (1) is mounted, characterized in that the detection device (4) is according to claim 2.

8. The bumper according to claim 7, characterized in that the emission element (6) is fastened to an inner transverse end portion (12) of the bumper and the reception element is arranged at the other inner transverse end portion (14) of the bumper.

9. The bumper according to claim 7, characterized in that the emission element (6) and the reception element (8) are embedded in the material of the bumper.

10. The bumper according to claim 7, characterized in that the second emission and reception elements (16, 18) are arranged under the first emission and reception elements (6, 8) of the detection device.

11. The bumper according to claim 7, characterized in that it comprises at least one conductive or partially conductive surface (20) arranged on the bumper (1) and inserted between the emission element (6) and the reception element (8) of the detection device (4), said surface (20) being connected to the ground said detection device (4).

12. A motor vehicle comprising at least one bumper (1), characterized in that the bumper (1) is according to claim 7.

13. The motor vehicle according to claim 11, characterized in that it comprises a second bumper (1) according to claim 7, one of the bumpers (1) being fastened to the front of the motor vehicle and the other bumper being fastened to the back of said vehicle.

14. A motor vehicle bumper (1) comprising a device (4) for detecting the presence of an object in a proximity detection zone of a motor vehicle on which the bumper (1) is mounted, characterized in that the detection device (4) is according to claim 1.

15. The bumper according to claim 14, characterized in that the emission element (6) is fastened to an inner transverse end portion (12) of the bumper and the reception element is arranged at the other inner transverse end portion (14) of the bumper.

16. The bumper according to claim 14, characterized in that the emission element (6) and the reception element (8) are embedded in the material of the bumper.

17. The bumper according to claim 14, characterized in that it comprises at least one conductive or partially conductive surface (20) arranged on the bumper (1) and inserted between the emission element (6) and the reception element (8) of the detection device (4), said surface (20) being connected to the ground said detection device (4).

18. A motor vehicle comprising at least one bumper (1), characterized in that the bumper (1) is according to claim 14.

19. The motor vehicle according to claim 11, characterized in that it comprises a second bumper (1) according to claim 14, one of the bumpers (1) being fastened to the front of the motor vehicle and the other bumper being fastened to the back of said vehicle.