Inflatable restraint system and method of controlling deployment thereof

• US 5,483,449 A
• Filed: 03/31/1994
• Issued: 01/09/1996
• Est. Priority Date: 03/31/1994
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delco Electronics Corporation (General Motors Company)
• Inventors: Caruso, Christopher M., Gray, Charles A., Nunan, Douglas A.
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): Walker, Tyrone V.
• Application Number:
  US08/220,646
• Time in Patent Office: 649 Days
• Field of Search: 364/424.05, 340/436, 340/669, 307/10.1, 280/734, 280/735, 180/274, 180/282
• US Class Current: 701/46
• CPC Class Codes: B60R 2021/01322 comprising variable thresholds, e.g. depending from other collision parameters
• 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 21/0133 by integrating the amplitude of the input signal
• CPC Class Codes: B60R 21/01336 using filtering

Abstract

A system and a method are provided wherein an air bag deployment command is issued if a crash event exceeds both an energy boundary curve and an oscillation boundary curve, and, furthermore, following detection of an onset of the crash event, filtered acceleration data exceeds an acceleration threshold. The threshold is preferably two-tiered to help discriminate between deployment and non-deployment events.

Claims

1. A method of controlling deployment of an inflatable restraint system for a motor vehicle, the method including the steps of sensing vehicle deceleration, comparing the vehicle deceleration sensed with a deceleration threshold to detect an onset of a crash event, integrating the sensed vehicle deceleration following detection of the onset of the crash event to determine a change in velocity value and comparing said change in velocity value with a velocity threshold value, wherein the improvement comprises the steps of:

filtering vehicle deceleration following detection of the onset of the crash event to obtain filtered deceleration;

comparing the filtered deceleration with a deceleration threshold value;

integrating the absolute value of a derivative of filtered deceleration to determine an oscillation value and comparing said oscillation value with an oscillation threshold value; and

commanding deployment of the restraint system when both said change in velocity value exceeds said velocity threshold value and said oscillation value exceeds said oscillation threshold value and when the filtered deceleration exceeds the said deceleration threshold value.

2. The method as defined in claim 1 wherein said velocity and oscillation threshold values are variable over a predetermined time from the onset of said crash event.

3. The method of claim 2 wherein the velocity threshold values form a velocity boundary curve which is a composite of a plurality of non-deployment events, and wherein the oscillation threshold values form an oscillation boundary curve which is a composite of a plurality of non-deployment events.

4. The method of claim 2 wherein the velocity threshold values form a velocity boundary curve which is a composite of peak velocity values at a plurality of points in time for each of a plurality of non-deployment events, and wherein the oscillation threshold values form an oscillation boundary curve which is a composite of peak oscillation values at said plurality of points in time for each of said plurality of non-deployment events.

5. The method of claim 1 wherein the deceleration threshold value is variable over a predetermined time from the onset of said crash event.

6. The method of claim 5 wherein the deceleration threshold value is two-tiered.

7. The method of claim 1 further comprising the steps of sampling vehicle deceleration and limiting the minimum and maximum oscillation change per sample.

8. The method of claim 1 wherein the step of filtering is accomplished with a software-based, low-pass filter.

9. An inflatable restraint system for a motor vehicle, the system including an inflatable device for protecting an occupant of the vehicle in a crash event, accelerometer means mounted on the vehicle, and processor means programmed to process data from said accelerometer means to detect an onset of a crash event and to thereafter determine whether the crash event is severe enough to deploy the device, wherein the improvement comprises:

the processor means is also programmed to filter the data from the accelerometer means to obtain filtered acceleration data following detection of the onset of the crash event and said crash event is determined to be severe enough to deploy the device if;

(1) the magnitude of a change of velocity of the vehicle following the onset of the crash event exceeds a time dependent change of velocity profile of a composite of a plurality of non-deployment events;

(2) the magnitude of an integral of the absolute value of a derivative of the filtered acceleration data exceeds a time dependent profile of at least one other non-deployment event; and

(3) the magnitude of the filtered acceleration data exceeds an acceleration threshold value.

10. The system of claim 9 wherein the acceleration threshold value is variable over a predetermined time from the onset of said crash event.

11. The system of claim 10 wherein the acceleration threshold value is two-tiered.