Hybrid inflator

• US 6,170,868 B1
• Filed: 07/13/1999
• Issued: 01/09/2001
• Est. Priority Date: 03/18/1994
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Renz, Robert N., Baglini, James L., Grages, Dean W., Butt, Ron J., Hamilton, Brian K., Parks, Brent A.
• Primary Examiner(s): English, Peter C.
• Application Number:
  US09/352,899
• Time in Patent Office: 546 Days
• Field of Search: 280/737, 280/736, 280/741, 280/742, 280/740
• US Class Current: 280/737
• CPC Class Codes: B60R 2021/26094 characterised by fluid flow controlling valves
• 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: C06B 45/10 the organic component containing a resin
• 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
• CPC Class Codes: C06D 5/06 by reaction of two or more solids
• CPC Class Codes: C06D 5/10 by reaction of solids with liquids
• CPC Class Codes: Y10T 137/1647 Explosive actuation

Abstract

A hybrid inflator that includes a solid propellant and a pressurized medium comprising oxygen and at least one inert gas is provided. The solid propellant can be fuel-rich in that without excess oxygen it generates significant amounts of CO and H₂. The at least one inert gas is contained in an inflator housing and the amount thereof is greater, on a molar basis, than the oxygen. The propellant has acceptable long-term stability in that such propellant does not ignite when exposed to a temperature of 107° C. for a period of 400 hours.

Claims

1. An inflator for inflating an inflatable in a vehicle, comprising:

an inflator housing;

a gas generator assembly interconnected with said inflator housing and including a gas generator housing;

a solid propellant including a secondary explosive that constitutes at least 50% by weight of said propellant, and wherein said propellant has the property that said propellant remains functional in the inflator when subject to a temperature of 107°

C. for a period of 400 hours and, when the inflator is activated, said solid propellant produces propellant gases that include amounts of carbon monoxide gas and hydrogen gas;

a pressurized medium stored in said inflator housing that includes at least one inert gas and oxygen, wherein said at least one inert gas, on a molar basis, is greater in amount than any nitrogen present in said pressurized medium and said oxygen is less in amount, on a molar basis, than said at least one inert gas and in which at least a majority, on a molar basis, of said pressurized medium is different from air and, when the inflator is activated, said oxygen combines with said carbon monoxide gas and said hydrogen gas to reduce said amounts thereof, said at least one inert gas and said oxygen together with said propellant gases, providing inflation gases that are received by the inflatable, with substantially all of said inflation gases that are received by the inflatable being said propellant gases said at least one inert gas and said oxygen, and in which said inflation gases are produced substantially independently of any flammable fuel gas; and

an inflator activation assembly for use in activating said propellant.

2. A hybrid inflator, as claimed in claim 1, wherein:

said at least one inert gas consists essentially of argon.

3. An inflator, as claimed in claim 2, wherein:

said at least one inert gas includes helium for use in detecting any leak of said pressurized medium.

4. An inflator, as claimed in claim 1, wherein:

said secondary explosive is selected from the group consisting of;

RDX (hexahydrotrinitrotriazine), HMX (cyclotetramethylenetetranitramine), PETN (petaerythriltol tetranitrate) and TAGN (triaminoguanidine nitrate).

5. An inflator, as claimed in claim 1, wherein:

said propellant comprises up to about 90% by weight of said secondary explosive.

6. An inflator, as claimed in claim 1, wherein:

said propellant comprises up to about 90% by weight of said secondary explosive and from about 10% to 50% by weight of a binder system.

7. An inflator, as claimed in claim 1, wherein:

said at least one inert gas, on a molar basis, is about 70% to 90% of said pressurized medium.

8. An inflator, as claimed in claim 1, wherein:

said at least one inert gas is selected from the group that consists of;

argon, helium and neon.

9. An inflator, as claimed in claim 1, wherein:

said solid propellant is selected from the group consisting of;

single-base propellants, double-base propellants, triple-base propellants and nitramine propellants.

10. An inflator, as claimed in claim 1, wherein:

a weight ratio of said pressurized medium to said propellant ranges from about 10;

1 to about 20;

1.

11. An inflator, as claimed in claim 1, wherein:

said weight of said propellant is less than about 15 grams.

12. An inflator, as claimed in claim 1, wherein:

a ratio of the gram moles of said propellant gases and said pressurized medium to the gram weight of said propellant ranges from about 0.35 to about 0.6 gram moles per gram.

13. An inflator for use in a vehicle, comprising:

a gas generator assembly including a gas generator housing;

an inflator housing including a first housing assembly and a second housing assembly interconnected with said first housing assembly, said second housing assembly including said gas generator housing and first and third chambers, said first housing assembly being disposed about said second housing assembly and spaced from said second housing assembly, and with a second chamber defined between said first housing assembly and said second housing assembly;

a propellant including a secondary explosive that constitutes at least 50% by weight of said propellant, and wherein said propellant has the property that said propellant remains functional in the inflator when subject to a temperature of 107°

C. for a period of 400 hours;

a pressurized medium stored in said inflator housing that includes at least one inert gas and oxygen, wherein said at least one inert gas, on a molar basis, is greater in amount than any nitrogen present in said pressurized medium and said oxygen is less in amount, on a molar basis, than said at least one inert gas and in which at least a majority, on a molar basis, of said pressurized medium is different from air; and

an inflator activation assembly for use in activating said propellent.

14. An inflator, as claimed in claim 13, wherein:

said second housing assembly has first and second ports, said first port interconnecting said first chamber and said second chamber and said second port interconnecting said second chamber and said third chamber and in which a first closure disk is disposed between said third chamber and an inflatable and wherein said activation assembly is a dual function activation assembly which is positioned for rupturing said first closure disk and igniting said propellant.

15. An inflator, as claimed in claim 14, further including:

means for substantially preventing direct fluid communication between said first and third chambers at all times, wherein gas generated upon ignition of said propellant is forced to flow from said first chamber, into said second chamber and then into said third chamber.

16. An inflator, as claimed in claim 15, wherein:

said means for substantially preventing direct fluid communication comprises a partition disposed within said second housing assembly, said partition substantially isolating said first chamber from said third chamber.

17. An inflator, as claimed in claim 16, wherein:

said partition has a bottom wall and said partition bottom wall is generally domed.

18. An inflator, as claimed in claim 15, wherein:

said means for substantially preventing direct fluid communication comprises a partition disposed within said second housing assembly that separates said first chamber from said third chamber, an aperture extending through said partition and a projectile slidably received within said aperture.

19. An inflator, as claimed in claim 13, wherein:

said first housing assembly is substantially cylindrical.

20. An inflator, as claimed in claim 13, wherein:

said first housing assembly is generally torus-shaped.