PRESSURE AND ACCELERATION BASED PEDESTRIAN IMPACT SENSOR ASSEMBLY FOR MOTOR VEHICLES

• US 20140052341A1
• Filed: 08/14/2012
• Published: 02/20/2014
• Est. Priority Date: 08/14/2012
• Status: Active Grant

• Current Assignee: Arriver Software LLC
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Leach, William M., Forwerck, Joshua, Pietzsch, Sylvia, Celik, Mustafa Cuma, Hfelsauer, Herbert
• Granted Patent: US 8,972,116 B2
• Time in Patent Office: Days
• US Class Current: 701/45
• CPC Class Codes: B60R 19/02 Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects B60R19/56 takes precedence; initiating brake action by contact of bumper with an external object B60T7/22; for rail vehicles B61F19/04; safety equipment for cycles B62J27/00; integral with waterborne vessels or specially adapted therefor B63B59/02
• CPC Class Codes: B60R 19/483 with obstacle sensors of electric or electronic type
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• 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
• CPC Class Codes: B60R 21/34 Protecting non-occupants of a vehicle, e.g. pedestrians B60R19/02 takes precedence
• CPC Class Codes: G01L 19/0092 Pressure sensor associated with other sensors, e.g. for measuring acceleration or temperature G01L9/025, G01L9/045, G01L9/065, G01L9/085, G01L9/105, G01L9/125, G01L19/02, G01L19/04 take precedence; measuring two or more variable G01D21/02; temperature sensors with pressure compensation G01K1/26
• CPC Class Codes: G01L 5/0052 measuring forces due to impact G01L5/0061, G01L5/14 take precedence; impact testing of structures G01M7/08; impact testing of material G01N3/00

Abstract

A sensor assembly for a motor vehicle adapted for sensing impacts including pedestrian impacts. The sensor assembly integrates functions of pressure based sensors used in one embodiment with a compressible tube extending laterally across the front surface of the vehicle and the outboard front boundary areas of the front end of the vehicle. Both acceleration and pressure based sensors are mounted into an integrated sensor housing which is mounted in a desired position at the vehicle front fascia front boundary areas. The system optimizes pressure based sensing while providing acceleration based sensing at the lateral boundary areas where supporting structure does not enable pressure based sensing. The invention further including sensor arrangements including discrete pressure and acceleration sensors deployed for detecting pedestrian impacts at the center and front boundary areas of the vehicle front end.

Claims

1. A low-energy impact sensor assembly for mounting to the front end of a motor vehicle for detecting a low energy impact such as a pedestrian impact for deploying an impact countermeasure, comprising;

an acceleration sensor in a housing with a mounting feature for affixing the housing to the motor vehicle at a predetermined position, the acceleration sensor having at least one sensing axis oriented in a predetermined orientation with respect to the motor vehicle, the acceleration sensor acting to detect the impact due to acceleration of the acceleration sensor, and

a compression sensor acting to detect the impact by compression of a component of the motor vehicle, the compression sensor and the acceleration sensor acting together to detect the impact.

2. A low-energy impact sensor assembly according to claim 1 further comprising the compression sensor mounted to the housing.

3. A low-energy impact sensor assembly according to claim 1 further comprising the compression sensor in the form of a pressure sensor communicating with an enclosed volume of a gas, wherein the pressure sensor detects the impact when the enclosed volume is decreased by compression during the impact.

4. A low-energy impact sensor assembly according to claim 3 further comprising the enclosed volume defined by a deformable pressure tube.

5. A low-energy impact sensor assembly according to claim 3 further comprising, a pair of the housing assemblies connected with opposing ends of the pressure tube.

6. A low-energy impact sensor according to claim 5 further comprising,

a first of the pair of housing assemblies mounted to a front end of the vehicle at a left-side front boundary area of the front end and a second of the pair of housing assemblies mounted to a right-side front boundary area of the front end.

7. A low-energy impact sensor assembly according to claim 4 further comprising,

Wherein the housing assembly and the pressure tube are mounted behind a fascia covering at least a portion of the front end.

8. A low-energy impact sensor assembly according to claim 7 further comprising, the tube mounted between the fascia and a bumper beam.

9. A low-energy impact sensor assembly according to claim 1 further comprising,

wherein the direction of the at least one sensing axis is oriented in a direction parallel to the longitudinal axis of the motor vehicle.

10. A low-energy impact sensor assembly according to claim 1 further comprising,

wherein the direction of the at least one sensing axis is oriented in a direction oblique to the longitudinal axis of the motor vehicle.

11. A low-energy impact sensor assembly according to claim 1 further comprising,

wherein the direction of the at least one sensing axis is oriented in a direction perpendicular to the longitudinal axis of the motor vehicle.

12. A low-energy impact sensor assembly according to claim 3 further comprising, the compression sensor mounted to the housing, the housing forming a hollow body having a PC board mounted therein, and wherein the acceleration sensor is mounted to one surface of the PC board and the pressure sensor is mounted to an opposing surface of the PC board.

13. A low-energy impact sensor assembly according to claim 12 further comprising the housing forming an internal volume communicating the pressure tube with the pressure sensor whereby compression of the tube generates a pressure acting on the pressure sensor.

14. A low-energy impact sensor system for a front end of a motor vehicle for detecting a pedestrian impact for deploying an impact countermeasure, the front end including a laterally extending cross beam and a pair of front boundary areas extending laterally outboard of the cross beam comprising;

an acceleration sensor having at least one sensing axis oriented in a predetermined orientation with respect to the motor vehicle, the acceleration sensor mounted to or adjacent to the front fascia in the front boundary area,

a pressure sensor communicating with an enclosed volume of a gas, the enclosed volume of gas extending laterally across the width of the cross beam wherein the pressure sensor detects the pedestrian impact when the enclosed volume is decreased by compression, and the acceleration sensor detects the pedestrian impact due to acceleration of the acceleration sensor, and

a restraint system controller receiving signals from at least one of the pressure sensor and the acceleration sensor to deploy the countermeasures based on at least one of a pressure signal from the pressure sensor and an acceleration signal from the acceleration sensor.

15. The low-energy impact sensor system according to claim 14 further comprising the enclosed volume defined by a pressure tube extending across the cross beam.

16. The low-energy impact sensor system according to claim 14 further comprising the enclosed volume defined by an energy absorbing member positioned between the front fascia and a cross beam of the vehicle.

17. The low-energy impact sensor system according to claim 16 further comprising at least a pair of the acceleration sensors mounted to or adjacent to the front fascia at each of the front boundary areas.

18. The low-energy impact sensor system according to claim 14 further comprising an acceleration sensor mounted to the cross beam.

19. A low-energy impact sensor assembly according to claim 14 further comprising,

wherein the direction of the sensing axis is oriented in a direction parallel to the longitudinal axis of the motor vehicle.

20. A low-energy impact sensor assembly according to claim 14 further comprising,

wherein the direction of the sensing axis is oriented in a direction oblique to the longitudinal axis of the motor vehicle.

21. A low-energy impact sensor assembly according to claim 14 further comprising,

wherein the direction of the sensing axis is oriented in a direction perpendicular to the longitudinal axis of the motor vehicle.