Variable output inflator for an air bag

• US 6,196,582 B1
• Filed: 09/22/1999
• Issued: 03/06/2001
• Est. Priority Date: 09/22/1999
• Status: Expired due to Fees

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Sparkman, John Paul, Ryan, Shawn Gregory, Niederman, Robert Raymond, Starner, Allen Richard
• Primary Examiner(s): Mar, Michael
• Assistant Examiner(s): JASMIN, LYNDA C
• Application Number:
  US09/400,588
• Time in Patent Office: 531 Days
• Field of Search: 280/741, 280/736, 280/740, 280/737, 280/742
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators

Abstract

The present invention presents an inflator providing variable output inflation of an air bag cushion in response to full or reduced level deployment conditions. The inflator of the present invention includes a first chamber for storing an inert gas, a second chamber in fluid communication with the first chamber, and a third chamber in selective fluid communication with the second chamber, the third chamber for storing a heat modifier for varying a heat value of the inert gas. The inflator also includes a pyrotechnic device having a combustible material for heating the inert gas and a first initiator for actuating the pyrotechnic device upon first and second deployment conditions. A second initiator for opening the third chamber to the second chamber is provided wherein actuation of the second initiator causing the heat modifier to fluidly communicate with the combustible material and vary the heat value of the inert gas during a combustion process. The second initiator is actuated during second deployment conditions.

Claims

1. An inflator for providing variable output inflation of an air bag cushion;

the inflator comprising;

a first chamber for storing an inert gas;

a second chamber in fluid communication with the first chamber,

a third chamber in selective fluid communication with the second chamber, the third chamber for storing a heat modifier for varying a heat value of the inert gas;

a pyrotechnic device having a combustible material for heating the inert gas;

a first initiator for actuating the pyrotechnic device upon first and second deployment conditions;

a second initiator for opening the third chamber to the second chamber, actuation of the second initiator causing the heat modifier to fluidly communicate with the combustible material and vary the heat value of the inert gas during a combustion process, the second initiator being actuated during second deployment conditions; and

a diffuser having a vent port for releasing the heated inert gas from the inflator.

2. The inflator as set forth in claim 1, wherein the heat modifier is selected from the group consisting of accelerants, inhibitors, and catalysts.

3. The inflator as set forth in claim 1, further comprising:

a first rupturable seal providing a gas tight barrier between the diffuser and the second chamber and a second rupturable seal providing a gas tight barrier between the second and third chambers.

4. The inflator as set forth in claim 1, wherein the first initiator opens a first fluid flow path permitting fluid communication between the diffuser and the first and second chambers upon the first and second deployment conditions.

5. The inflator as set forth in claim 3, wherein the first initiator includes a first projectile for rupturing the first rupturable seal, and a first squib that provides a charge to propel the first projectile upon first and second level deployment conditions;

and

wherein the second initiator includes a second projectile for rupturing the second rupturable seal, and a second squib that provides a charge to propel the second projectile upon the second level deployment condition.

6. The inflator as set forth in claim 1, wherein the heat modifier comprises an accelerant, whereby the output inflation under first level deployment condition is less than the output inflation under second level deployment condition.

7. The inflator as set forth in claim 1, wherein the heat modifier comprises a catalyst, whereby the output inflation under first level deployment conditions is less than the output inflation under second level deployment conditions.

8. The inflator as set forth in claim 1, wherein the heat modifier comprises an inhibitor, whereby the output inflation under first level deployment conditions is greater than the output inflation under second level deployment conditions.

9. The inflator as set forth in claim 1, wherein the second chamber is formed by an inner cylindrical wall extending between a housing, the inner cylindrical wall including first and second apertures permitting fluid communication between the first chamber and the second and third chambers.

10. A method for variably inflating an air bag cushion using an air bag inflator, the method comprising:

providing a first chamber for storing an inert gas;

providing a second chamber in fluid communication with the first chamber;

providing a third chamber in selective communication with the first chamber, the third chamber for storing a heat modifier for varying a heat value of the inert gas;

providing a diffuser having a vent port for releasing heated gas to the air bag cushion;

igniting a pyrotechnic device to heat the inert gas upon first and second level deployment conditions;

opening the third chamber to permit fluid communication of the heated gas from the third chamber to the second chamber causing the heat modifier to fluidly communicate with combustible material in the pyrotechnic device and vary the heat value of the inert gas during a combustion process, the third chamber being opened under second level deployment conditions; and

opening the second chamber to permit fluid communication of the heated gas from the second chamber to the diffuser upon the first and second level deployment conditions.

11. The method as set forth in claim 10, wherein the opening of the second chamber comprises actuating a first initiator to rupture a first gas tight seal disposed between the second chamber and the vent port of the diffuser;

and

wherein the opening of the third chamber comprises actuating a second initiator to rupture a second gas tight seal disposed between the second and third chambers, under second level deployment conditions.

12. The method as set forth in claim 10, wherein the heat modifier is selected from the group consisting of accelerants, inhibitors, and catalysts.

13. The method as set forth in claim 10, wherein the modifier is an accelerant, whereby the output inflation under the first level deployment conditions is less than the output inflation under second level deployment conditions.

14. The method as set forth in claim 10, wherein the modifier is a catalyst, whereby the output inflation under first level deployment conditions is less than the output inflation under second level deployment conditions.

15. The method as set forth in claim 10, wherein the modifier is an inhibitor, whereby the output inflation under first level deployment conditions is less than the output inflation under second level deployment conditions.