Supplemental restraint deployment method providing rough road immunity

• US 6,154,698 A
• Filed: 07/30/1998
• Issued: 11/28/2000
• Est. Priority Date: 07/30/1998
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delco Electronics Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Bubolz, Gretchen Elizabeth, Reprogle, Kristi Kay, Walden, Michael K., Dalum, Joseph Thomas, Patterson, Sheri Lynn
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): MARC-COLEMAN, MARTHE Y
• Application Number:
  US09/124,775
• Time in Patent Office: 852 Days
• Field of Search: 701/45, 701/46, 180/271, 180/282, 280/734, 280/735, 307/10.1
• US Class Current: 701/45
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value

Abstract

An improved deployment method for a vehicular supplemental restraint system, wherein the existence of a rough road condition is indicated if a measure of crash severity obtained from an acceleration sensor exceeds a rough road threshold and the crash event reset criteria are subsequently met with no intervening deployment of the restraint device. The rough road indication is maintained for a timed period, and normal deployment of the restraint device is inhibited during the timed period unless the acceleration signal exceeds a minimum threshold and the measure of crash severity exceeds an additional deployment threshold which is initially higher than the normal deployment threshold. When the rough road condition is detected, a counter is initialized to a predefined value, and then periodically indexed so long as no potential crash event is in progress. If the counter is indexed to another predefined value prior to another rough road detection, the rough road condition is reset. A severe rough road will produce multiple initializations of the counter, resulting in a prolonged rough road indication, whereas a single rough road impact will result in a much shorter rough road indication. Raising the crash severity threshold in the presence of a rough road condition increases immunity to rough road events and allows the use of relatively aggressive reset criteria, while retaining the ability to properly deploy the restraints in a concatenated crash event.

Claims

1. A deployment method for vehicular supplemental restraint system having an acceleration sensor and a restraint device to be deployed for occupant protection in a crash event, the method comprising the steps of:

monitoring an output signal of the acceleration sensor to generate an indication of a potential crash event initiation;

resetting the indication of crash event initiation if the output signal falls below a reset threshold for at least a predetermined period of time;

processing the acceleration sensor output signal to obtain a measure of crash severity, beginning each time said indication of potential crash event initiation is generated;

normally deploying the restraint device if the measure of crash severity exceeds a primary deployment threshold indicative of a severe crash event;

generating an indication of a rough road condition if (a) the measure of crash severity exceeds a rough road threshold and (b) the indication of crash event initiation is subsequently reset with no intervening deployment of the restraint device;

inhibiting the normal deploying of the restraint device in response to the generation of said indication of a rough road condition; and

deploying the restraint device despite the indication of a rough road condition if the measure of crash severity exceeds a secondary deployment threshold which is initially higher than said primary deployment threshold.

2. The method set forth in claim 1, including the step of:

resetting said indication of a rough road condition a predetermined period of time after the generation of such indication unless another indication of a potential crash event initiation is generated.

3. The method set forth in claim 1, wherein the generation of an indication of a rough road condition includes the steps of:

initializing a counter to a predefined value;

periodically indexing said counter so long as another indication of a potential crash event initiation is not generated; and

resetting said indication of a rough road condition when said counter reaches a reference value.

4. The method of claim 3, including the step of:

re-initializing said counter to said predefined value each time the measure of crash severity exceeds the rough road threshold and the indication of crash event initiation is subsequently reset with no intervening deployment of the restraint device.

5. A deployment method for vehicular supplemental restraint system having an acceleration sensor and a restraint device to be deployed for occupant protection in a crash event, the method comprising the steps of:

monitoring an output signal of the acceleration sensor to generate an indication of a potential crash event initiation;

resetting the indication of crash event initiation if the output signal falls below a reset threshold for at least a predetermined period of time;

processing the acceleration sensor output signal to obtain a measure of crash severity, beginning each time said indication of potential crash event initiation is generated;

normally deploying the restraint device if the measure of crash severity exceeds a primary deployment threshold indicative of a severe crash event;

generating an indication of a rough road condition for a timed period if (a) the measure of crash severity exceeds a rough road threshold and (b) the indication of crash event initiation is subsequently reset with no intervening deployment of the restraint device;

inhibiting the normal deploying of the restraint device during said timed period if the measure of crash severity is less than a secondary deployment threshold which is initially higher than said primary deployment threshold; and

deploying said restraint device during said timed period if the measure of crash severity exceeds said secondary deployment threshold.

6. The method set forth in claim 5, including the step of:

extending a duration of said timed period if another indication of a potential crash event initiation is generated during said timed period.

7. The method set forth in claim 5, wherein the generation of an indication of a rough road condition includes the steps of:

initializing a counter to a predefined value;

periodically indexing said counter so long as another indication of a potential crash event initiation is not generated; and

resetting said indication of a rough road condition when said counter reaches a reference value.

8. The method of claim 7, including the step of:

re-initializing said counter to said predefined value each time the measure of crash severity exceeds the rough road threshold and the indication of crash event initiation is subsequently reset with no intervening deployment of the restraint device.

9. A deployment method for vehicular supplemental restraint system having an acceleration sensor and a restraint device to be deployed for occupant protection in a crash event, the method comprising the steps of:

monitoring an output signal of the acceleration sensor to generate an indication of a potential crash event initiation;

resetting the indication of crash event initiation if the output signal falls below a reset threshold for at least a predetermined period of time;

processing the acceleration sensor output signal to obtain a measure of crash severity, beginning each time said indication of potential crash event initiation is generated;

normally deploying the restraint device if the measure of crash severity exceeds a primary deployment threshold indicative of a severe crash event;

initializing a counter to indicate a rough road condition if (a) the measure of crash severity exceeds a rough road threshold and (b) the indication of crash event initiation is subsequently reset with no intervening deployment of the restraint device;

periodically indexing said counter so long as another indication of a potential crash event is not generated;

resetting said counter when a count stored in the counter reaches a predefined value; and

inhibiting the normal deploying of the restraint device between the initializing and resetting of said counter if the measure of crash severity is less than a secondary deployment threshold which is initially higher than said primary deployment threshold; and

deploying said restraint device between the initializing and resetting of said counter if the measure of crash severity exceeds said secondary deployment threshold.

10. The method of claim 9, including the step of:

re-initializing said counter each time the measure of crash severity exceeds the rough road threshold and the indication of crash event initiation is subsequently reset with no intervening deployment of the restraint device.