Variable time venting algorithm

• US 20040084883A1
• Filed: 03/17/2003
• Published: 05/06/2004
• Est. Priority Date: 10/31/2002
• Status: Active Grant

• Current Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Key Safety Systems, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Gioutsos, Tony, Tabar, Daniel
• Granted Patent: US 6,789,818 B2
• Time in Patent Office: Days
• US Class Current: 280/739
• CPC Class Codes: B60R 2021/01218 control of expansion speed
• CPC Class Codes: B60R 21/01504 detecting bag displacement

Abstract

An algorithm for evaluating information from sensors interacting with strips that are extended during activation of the airbag determines whether the airbag has contacted an out-of-position occupant. In one embodiment, each strip includes an alternating pattern that generates a frequency in a sensor through which the strip passes during deployment. The frequency generated is based upon the speed with which the strip passes by the sensor and, in turn, the speed of deployment of the airbag. A controller evaluates the frequency and the changes in frequency from the sensor during deployment. Depending upon the specific configuration of the system and the specific vehicle, a decrease in the speed of deployment of the airbag may be indicated by a decrease in the frequency of the signal. A decrease in speed of deployment may indicate that the airbag is in contact with an occupant

Claims

1. A vehicle airbag system comprising:

an airbag;

an airbag inflator for selectively inflating the airbag and reducing inflation of the airbag based upon a determination that the airbag has contacted an occupant.

2. The system of claim 1 wherein the airbag inflator reduces inflation of the airbag based upon a velocity of deployment of the airbag.

3. The system of claim 2 further including means for determining a deployment velocity of the airbag.

4. The system of claim 1 further including a sensor determining a velocity of deployment of the airbag, the airbag inflator reducing inflation of the airbag based upon the velocity of deployment.

5. The system of claim 4 wherein the airbag inflator reduces inflation of the airbag based upon a decrease in velocity of deployment of the airbag.

6. The system of claim 5 further including at least one strip connected to the airbag, the sensor determining a velocity of the strip to determine the velocity of deployment of the airbag.

7. The system of claim 6 wherein the at least one strip includes a pattern that generates a frequency in the sensor that varies based upon the velocity of the strip.

8. The system of claim 7 further including a controller applying a frequency domain transform to a signal from the sensor, the controller analyzing the frequency domain transform to determine whether the airbag has contacted an occupant.

9. The system of claim 8 wherein the controller applies a Welsh transform of the signal from the sensor.

10. The system of claim 9 wherein the controller determines whether the airbag has contacted an occupant by analyzing a change in the frequency from the sensor.

11. A method for activating an airbag including the steps of:

a. initiating inflation of an airbag;

b. determining whether the airbag has contacted an occupant; and

c. ceasing or continuing inflation of the airbag based upon said step b.

12. The method of claim 11 wherein said step b is based upon a speed of travel of the airbag.

13. The method of claim 12 wherein said step b is based upon a change in the velocity of travel of the airbag.

14. The method of claim 13 further including the step of generating a frequency proportional to the speed of travel of the airbag.

15. The method of claim 14 further including the step of:

d. analyzing the frequency;

said step b based upon said step d.

16. The method of claim 15 wherein said step d further includes the step of analyzing a change in the frequency.

17. The method of claim 16 wherein said step d further includes the steps of:

e. applying a frequency domain transform to the frequency;

f. analyzing the frequency domain transform to determine whether the airbag has contacted an occupant.

18. The method of claim 17 further including the step of ceasing inflation of the airbag based upon a determination that the airbag has contacted an out-of-position occupant.

19. The method of claim 18 further including the step of venting an airbag inflator in order to perform the step of ceasing inflation.

20. The method of claim 19 wherein the frequency domain transform is a Walsh transform.

21. A computer readable medium storing a computer program which when executed by a computer performs the steps of:

a. analyzing a speed of deployment of an airbag;

b. determining whether the airbag has contacted an out-of-position occupant; and

c. controlling an airbag to cease or continue inflation based upon said step b.

22. The computer readable medium of claim 21 further performing the steps of:

d. receiving a signal indicative of the speed of deployment of the airbag; and

e. analyzing frequency components of the signal in order to perform said step b.

23. The computer readable medium of claim 22 further performing the steps of:

f. performing a frequency domain transform in order to analyze the frequency components of the signal in said step e.

24. The computer readable medium of claim 23 wherein the frequency domain transform is a Walsh transform.