Hybrid inflator with a valve

• US 5,630,618 A
• Filed: 09/11/1995
• Issued: 05/20/1997
• Est. Priority Date: 03/18/1994
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: OEA Incorporated (Autoliv Incorporated)
• Inventors: Hamilton, Brian K., Parks, Brent A.
• Primary Examiner(s): Dickson, Paul N.
• Application Number:
  US08/518,925
• Time in Patent Office: 617 Days
• Field of Search: 280/736, 280/737, 280/741, 222/3, 222/5
• US Class Current: 280/736
• 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

Abstract

A hybrid inflator comprises an inflator housing which contains a pressurized medium and a gas generator. The gas generator comprises a gas generator housing, a propellant contained within the gas generator housing, a gas generator inlet port which fluidly interconnects the gas generator housing and the inflator housing, and a gas generator outlet port which fluidly interconnects the gas generator housing and the air/safety bag. The inflator also includes a propellant ignition assembly interconnected with the gas generator and a valve operatively associated with the gas generator inlet port. The valve substantially inhibits flow between the inflator housing and the gas generator housing through the gas generator inlet port until a pressure within the inflator housing exceeds a pressure within the gas generator housing by a predetermined degree after the propellant ignition assembly is activated.

Claims

1. A hybrid inflator for an automotive inflatable safety system comprising an air/safety bag, said inflator comprising:

a stored gas housing which contains a pressurized medium;

a gas generator comprising a gas generator housing, a propellant contained within said gas generator housing, at least one gas generator inlet port which fluidly interconnects said gas generator housing and said inflator housing, and at least one gas generator outlet port which fluidly interconnects said gas generator housing and the air/safety bag;

a propellant ignition assembly interconnected with said gas generator; and

valve means, operatively associated with said at least one gas generator inlet port, for substantially inhibiting flow between said inflator housing and said gas generator housing through said at least one gas generator inlet port until a pressure within said inflator housing exceeds a pressure within said gas generator housing by a predetermined degree after said propellant ignition assembly is activated.

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

said pressures within said inflator housing and said gas generator housing are substantially equally maintained before said propellant ignition assembly is activated.

3. A hybrid inflator as claimed in claim 1, further comprising:

a plurality of said gas generator inlet ports, wherein said valve means is operatively associated with each of said plurality of said gas generator inlet ports.

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

said gas generator housing comprises first and second fluidly interconnected chambers, said propellant being within said first chamber, said second chamber being positioned between said at least one gas generator outlet and said first chamber.

5. A hybrid inflator as claimed in claim 4, further comprising:

a closure disk between said at least one gas generator outlet and the air/safety bag;

means for pressurizing said second chamber of said gas generator housing at a greater rate than said inflator housing after ignition of said propellant; and

means for opening said closure disk, said means for opening comprising said means for pressurizing.

6. A hybrid inflator as claimed in claim 5, wherein:

said means for pressurizing comprises an aspirator nozzle disposed between said first and second chambers.

7. A hybrid inflator as claimed in claim 5, wherein:

said means for pressurizing comprises means for inducing a vortex flow within said second chamber.

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

said valve means is movable from a first position to a second position, said valve means being in said first position and substantially inhibiting said flow when operational and moving to said second position and allowing said flow when said pressure within said inflator housing exceeds said pressure within said gas generator housing by a predetermined degree, said second position being radially inward of said first position.

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

said valve means comprises a pliable member positioned within said gas generator housing, wherein said pliable member is pressed into substantial abutting relationship with said gas generator housing and thereby blocks said at least one gas generator inlet port until said pressure in said inflator housing exceeds said pressure in said gas generator housing by said predetermined degree, and wherein said pliable member moves away from said gas generator housing after said pressure in said inflator housing exceeds said pressure in said gas generator housing by said predetermined degree, whereby a flow from said inflator housing into said gas generator housing through said at least one gas generator inlet port is established.

10. A hybrid inflator as claimed in claim 9, wherein:

said pliable member is made of a metallic sheet.

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

said valve means comprises a plug associated with said at least one gas generator inlet port, said plug being movable from a first position for blocking said at least one gas generator inlet port to a second position for opening said inlet port.

12. A hybrid inflator as claimed in claim 11 wherein:

said plug is supported by a pliable member.

13. A method for operating an inflatable safety system comprising an air/safety bag and an inflator comprising an inflator housing, a pressurized medium contained within said inflator housing, a main closure disk disposed between said pressurized medium and the air/safety bag, and a gas generator fluidly interconnected with said inflator housing and comprising first and second fluidly interconnected chambers, said first chamber containing a propellant, wherein said second chamber is positioned between said first chamber and said main closure disk, interfaces with said main closure disk, and is fluidly interconnectable with said inflator housing by a plurality of ports, said method comprising the steps of:

generating propellant gases from said propellant;

providing at least a portion of said propellant gases from said first chamber to said second chamber;

substantially inhibiting a flow of said propellant gases from said second chamber into said inflator housing during a first portion of said generating step, said substantially inhibiting step comprising at least one of performing first and second steps, said performing a first step comprising biasing a valve assembly, disposed within said second chamber of said gas generator, toward sealing engagement with said gas generator to substantially seal said ports, said performing a second step comprising pressurizing said second chamber, wherein said ports are substantially sealed by said pressurizing step;

opening said main closure disk using said substantially inhibiting step;

allowing a flow from said inflator housing into said second chamber during a second portion of said generating step and after said substantially inhibiting step; and

directing a flow to the air/safety bag after said opening step.

14. A method, as claimed in claim 13, wherein:

said opening step comprises providing a flow path from said second chamber to said main closure disk and exerting a rupturing fluid pressure directly on said main closure disk through said flow path.

15. A method, as claimed in claim 13, wherein:

said generating step comprises generating propellant gases with a toxicity, said method further comprising the step of mixing said propellant gases and said pressurized medium to reduce said toxicity of said propellant gases and to combust said propellant gases.

16. A method, as claimed in claim 13, wherein:

said providing step comprises inducing a vortex flow within said second chamber.

17. A method, as claimed in claim 13, wherein:

said providing step comprises introducing a flow from said first chamber into said second chamber with at least a peripheral velocity component.

18. A method, as claimed in claim 13, wherein:

said substantially inhibiting step continues after said opening step.

19. A method, as claimed in claim 13, wherein:

said substantially inhibiting step comprises blocking a flow path between said inflator housing and said gas generator with said valve assembly.

20. A method, as claimed in claim 19, wherein:

said allowing step comprises moving said valve assembly out of said flow path between said inflator housing and said gas generator.

21. A method, as claimed in claim 20, wherein:

said moving step comprises collapsing at least a portion of said valve assembly.

22. A method, as claimed in claim 20, wherein:

said moving step comprises sensing a predetermined pressure differential between a pressure in said inflator housing and a pressure in said second chamber.

23. A method, as claimed in claim 13, wherein:

said opening step comprises pressurizing said second chamber at a greater rate than said inflator housing with said propellant gases from said generating step.

24. A method, as claimed in claim 13, wherein:

said allowing step is performed when a pressure within said inflator housing exceeds a pressure within said second chamber by a certain amount.

25. A method, as claimed in claim 13, wherein:

said allowing step comprises inducing a circulatory flow within said second chamber.

26. A method, as claimed in claim 13, wherein:

said allowing step comprises introducing said flow from said inflator housing into said second chamber with at least a peripheral velocity component.

27. A method, as claimed in claim 13, further comprising the step of:

monitoring a pressure within said inflator housing and a pressure within said second chamber, wherein a termination of said substantially inhibiting step and a starting of said allowing step is based upon said monitoring step.

28. A method, as claimed in claim 13, further comprising the step of:

providing a portion of said propellant gases from said first chamber to said inflator housing.

29. A method, as claimed in claim 13, further comprising the step of:

maintaining a predetermined differential pressure between said inflator housing and said second chamber for a predetermined period of time after said directing step.

30. A method, as claimed in claim 13, further comprising the steps of:

retaining a supply of said pressurized medium in said second chamber before said generating step; and

reacting said pressurized medium in said second chamber with said propellant gases before said allowing step.