Multiple level fluid fueled airbag inflator

• US 5,836,610 A
• Filed: 07/01/1997
• Issued: 11/17/1998
• Est. Priority Date: 05/31/1994
• Status: Expired due to Fees

• Current Assignee: Morton International Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Beus, Glen S., Green, David J., Rink, Karl K., Moore, Walter A.
• Primary Examiner(s): Dickson, Paul N.
• Application Number:
  US08/886,778
• Time in Patent Office: 504 Days
• Field of Search: 280/737, 280/735, 280/741, 280/736
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 2021/2725 using a fluid fuel gas generator
• CPC Class Codes: B60R 21/01526 using piezoelectric elements
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators
• CPC Class Codes: C06D 5/00 Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets explosive compositions containing an oxidizer, fuels for rocket engines intended for reaction with an oxidant other than air C06B

Abstract

An improvement in an air bag system for a motor vehicle relating to a multiple level fluid fueled air bag inflator and method of operation thereof are provided. Such a multiple level inflator includes a stored gas chamber, a combustion chamber wherein, upon actuation, a fluid fuel and an oxidant are burned, an opener to open the stored gas chamber and an initiator device to initiate the burning of the fluid fuel and oxidant in the combustion chamber. Various performance levels can be obtained through the proper selected actuation and sequencing of actuation of the opener and the initiator device.

Claims

1. In an air bag system for a motor vehicle, the system comprising at least one air bag module containing at least one inflatable air bag and sensor means for sensing at least one air bag system operating condition selected from the group of ambient temperature, occupant presence, seat belt usage and deceleration of the motor vehicle, the improvement comprising:

a multiple level air bag inflator coupled to the at least one air bag module, said multiple level air bag inflator adapted to produce and release, to the air bag, inflation gas at multiple inflation levels, said multiple level air bag inflator containing at least one fluid fuel and at least one oxidant and comprising;

a first chamber containing a supply of pressurized stored gas, said first chamber including at least one gas exit port and having sealing means normally closing the at least one gas exit port;

opening means to open the at least one gas exit port whereby at least a portion of the contents of said first chamber are expelled from said first chamber;

directing means for directing the expelled contents of said first chamber to the air bag;

a second chamber containing the at least one fluid fuel stored separately from the at least one oxidant wherein, upon actuation, the at least one fluid fuel and the at least one oxidant are contacted and burned to produce combustion products including hot combustion gas, said second chamber including at least one gas exit opening and having sealing means normally closing the at least one gas exit opening, the second chamber sealing means having a first surface adjacent said first chamber and a second surface adjacent said second chamber such that upon opening of the second chamber sealing means said second chamber is in fluid communication with said first chamber, the second chamber sealing means adapted to open when the difference in pressure at the first and the second surfaces becomes sufficiently large, whereby at least a portion of the contents of said second chamber are passed into said first chamber; and

initiator means for initiating the burning of the at least one fluid fuel and the at least one oxidant in said second chamber;

wherein, upon receipt by the module of a first level output from the sensor means, the gas released from said multiple level air bag inflator is free of combustion products and

wherein, upon receipt by the module of a third level output from the sensor means, the gas released from said multiple level air bag inflator comprises at least a portion of the stored gas and at least a portion of the combustion products produced by burning the at least one fluid fuel and the at least one oxidant in said second chamber.

2. The improvement of claim 1 wherein the fluid fuel of the multiple level air bag inflator comprises a gaseous form.

3. The improvement of claim 1 wherein the fluid fuel of the multiple level air bag inflator comprises a liquid form.

4. The improvement of claim 1 wherein the fluid fuel of the multiple level air bag inflator comprises a C₁ -C₄ paraffinic hydrocarbon.

5. The improvement of claim 4 wherein the fluid fuel of the multiple level air bag inflator comprises butane.

6. The improvement of claim 1 wherein the fluid fuel of the multiple level air bag inflator comprises an alcohol of no more than four carbon atoms.

7. The improvement of claim 6 wherein the fluid fuel of the multiple level air bag inflator comprises ethyl alcohol.

8. A method of operation of a multiple level air bag inflator in an air bag system for a motor vehicle, the system comprising at least one air bag module containing at least one inflatable air bag and sensor means for sensing at least one air bag operating condition selected from the group of ambient temperature, occupant presence, seat belt usage and deceleration of the motor vehicle, the air bag inflator containing at least one fluid fuel and at least one oxidant and having:

a) a first chamber containing a supply of pressurized stored gas, the first chamber including at least one gas exit port and having sealing means normally closing the at least one gas exit port;

b) opening means to open the at least one gas exit port whereby at least a portion of the contents of the first chamber are expelled from the first chamber;

c) directing means for directing the expelled contents of the first chamber to the inflatable air bag;

d) a second chamber containing a supply of the at least one fluid fuel stored separately from the at least one oxidant and wherein, upon actuation, the at least one fluid fuel and the at least one oxidant are contacted and burned to produce combustion products including hot combustion gas, the second chamber including at least one gas exit opening and having sealing means normally closing the gas exit opening, the second chamber sealing means having a first surface adjacent the first chamber and a second surface adjacent the second chamber such that upon opening of the second chamber sealing means the second chamber is in fluid communication with the first chamber, the second chamber sealing means adapted to open when the difference in pressure at the first and the second surfaces becomes sufficiently large, whereby at least a portion of the contents of the second chamber are passed into the first chamber; and

e) initiator means for initiating the burning of the at least one fluid fuel and the at least one oxidant in the second chamber;

wherein;

1) in response to receipt by the module of a first level output from the sensor means, said method comprises the steps of;

opening the at least one gas exit port, and

releasing, to the inflatable air bag, inflation gas free of combustion products; and

2) in response to receipt by the module of a third level output from the sensor means, said method comprises the steps of;

initiating and burning the at least one fluid fuel and the at least one oxidant in the second chamber,

opening the at least one gas exit port and the second chamber sealing means, and

releasing, to the inflatable airbag, inflation gas comprising at least a portion the stored gas and at least a portion of the combustion products produced by burning the at least one fluid fuel and the at least one oxidant in the second chamber.

9. The method of claim 8 wherein the fluid fuel of the multiple level air bag inflator comprises a gaseous form.

10. The method of claim 8 wherein the fluid fuel of the multiple level air bag inflator comprises a liquid form.

11. The method of claim 8 wherein the fluid fuel of the multiple level air bag inflator comprises a C₁ -C₄ paraffinic hydrocarbon.

12. The method of claim 11 wherein the fluid fuel of the multiple level air bag inflator comprises butane.

13. The method of claim 8 wherein the fluid fuel of the multiple level air bag inflator comprises an alcohol of no more than four carbon atoms.

14. The method of claim 13 wherein the fluid fuel of the multiple level air bag inflator comprises ethyl alcohol.