Inflator with multiple initiators

• US 6,189,922 B1
• Filed: 09/21/1998
• Issued: 02/20/2001
• Est. Priority Date: 09/21/1998
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Struckman, David W., Pierce, Stanley W., Hamilton, Brian K., Parks, Brent A., Butt, Ron J.
• Primary Examiner(s): English, Peter C.
• Application Number:
  US09/157,742
• Time in Patent Office: 883 Days
• Field of Search: 280/737, 280/736, 280/741, 280/735
• US Class Current: 280/735
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 21/01558 monitoring crash strength
• 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

A dual initiator inflator for selective activation, depending upon detection of a low impact vehicle collision or a high impact vehicle collision, is provided for use with an air bag in a vehicle. The inflator can be configured to function at any one of a number of vehicle locations, including a driver side inflator and a passenger side inflator. The inflator includes first and second initiators and first and second propellants. When a low impact vehicle collision is detected, the first initiator is triggered to ignite the first propellant. Essentially all inflation gases that are received in the air bag are due to products of combustion from the first propellant and stored gas contained in the inflator housing. After a predetermined time delay, the second propellant is ignited by the second initiator so that no combustible propellant remains after inflator usage. When a high impact vehicle collision is detected, both first and second propellants are ignited at essentially the same time so that inflation gases received by the air bag are the result of products of combustion from both the first and second propellants, together with the stored gas.

Claims

1. A dual initiator inflator for providing inflation gas to an inflatable located in a vehicle, comprising:

an inflator housing for storing a pressurized medium;

a first gas generating assembly including a first propellant that generates products of combustion including a first propellant gas;

a first initiator assembly for initiating ignition of said first propellant;

a second gas generating assembly including a second propellant that generates products of combustion including a second propellant gas;

a second initiator assembly for initiating ignition of said second propellant;

an outlet assembly through which inflation gas, which includes at least one of the first propellant gas and the second propellant gas, passes into the inflatable in the vehicle; and

a control system operatively associated with said first and second initiator assemblies for controlling activation thereof;

wherein, when the vehicle is subject to a low impact event, said first initiator assembly is activated using said control system and the inflatable is inflated using inflation gas to a first pressure and, after a delay beginning with activation of said first initiator assembly, said second initiator assembly is activated using said control system, with substantially all of the propellant gas that passes to the inflatable being generated by said first propellant and substantially no propellant gas is received in the inflatable from said second propellant when said low impact event is detected and, when the vehicle is subject to a high impact event, said first initiator assembly and said second initiator assembly are activated substantially at the same time and the inflatable is inflated using inflation gas that includes both the first propellant gas and the second propellant gas to a second pressure, with said second pressure being greater than said first pressure.

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

said delay is greater than about 100 msec.

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

said second gas generating assembly includes a second gas generating housing having an open end through which products of combustion from said second propellant exit said second gas generating housing when said second propellant is ignited and in which said first gas generating assembly includes a first gas generating housing having an outlet member with holes through which propellant gases generated by said first propellant exit said first gas generating housing, with said holes being non-coaxial with said open end of said second gas generating housing.

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

said holes are radially positioned on said outlet member of said first gas generating housing.

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

said second gas generating assembly includes an injector member having ports through which propellant gases pass when said second propellant is ignited and in which said injector member is disposed between said open end and said second propellant.

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

said first initiator assembly includes a first initiator and a first passageway and said first gas generating assembly includes a first chamber that contains said first propellant and a chamber closure member that has a first portion which opens when said first initiator is activated so that said first passageway communicates with said first chamber.

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

at least one of said first and second gas generating assemblies includes a chamber closure member and said second gas generating assembly includes a propellant cup and in which said chamber closure member is joined to a bottom of said propellant cup.

8. A dual initiator inflator for providing inflation gas to an inflatable located in a vehicle, comprising:

an inflator housing for storing a pressurized medium;

a first gas generating assembly including a first propellant that generates products of combustion including a first propellant gas;

a first initiator assembly for initiating ignition of said first propellant, said first initiator assembly including a first initiator and a first passageway, said first gas generating assembly including a first chamber that contains said first propellant and in which said first passageway communicates with said first chamber when said first initiator is activated, and with the inflator having a center axis spaced from said first initiator and said first initiator having a longitudinal, center axis and with said first passageway spaced laterally from said longitudinal, center axis of said first initiator;

a second gas generating assembly including a second propellant that generates products of combustion including a second propellant gas;

a second initiator assembly for initiating ignition of said second propellant;

an outlet assembly through which inflation gas, which includes at least one of the first propellant gas and the second propellant gas, passes into the inflatable in the vehicle; and

a control system operatively associated with said first and second initiator assemblies for controlling activation thereof;

wherein, when the vehicle is subject to a low impact event, said first initiator assembly is activated using said control system and, after a delay beginning with activation of said first initiator assembly, said second initiator assembly is activated using said control system.

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

said second initiator assembly includes a second initiator and a second passageway, said second gas generating assembly includes a second chamber that contains said second propellant and in which said second passageway communicates with said second chamber when said second initiator is activated, and with said second initiator having a longitudinal, center axis and with said second passageway spaced laterally from said longitudinal, center axis of said second initiator.

10. A dual initiator inflator for providing inflation gas to an inflatable located in a vehicle, comprising:

an inflator housing for storing a pressurized medium;

a first gas generating assembly including a first propellant that generates products of combustion including a first propellant gas;

a first initiator assembly for initiating ignition of said first propellant, said first initiator assembly including a first initiator and a first passageway and said first gas generating assembly including a first chamber that contains said first propellant and a chamber closure member that has a first portion which opens when said first initiator is activated so that said first passageway communicates with said first chamber;

a second gas generating assembly including a second propellant that generates products of combustion including a second propellant gas;

a second initiator assembly for initiating ignition of said second propellant, said second initiator assembly including a second initiator and a second passageway, said second gas generating assembly including a second chamber that contains said second propellant and in which said chamber closure member has a second portion that opens when said second initiator is activated so that said second passageway communicates with said second chamber;

an outlet assembly through which inflation gas, which includes at least one of the first propellant gas and the second propellant gas, passes into the inflatable in the vehicle; and

a control system operatively associated with said first and second initiator assemblies for controlling activation thereof;

wherein, when the vehicle is subject to a low impact event, said first initiator is activated using said control system and, after a delay beginning with activation of said first initiator, said second initiator is activated using said control system.

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

said second gas generating assembly includes a propellant cup in which said second propellant is contained and in which said chamber closure member is joined to said propellant cup.

12. A dual initiator inflator for providing inflation gas to an inflatable located in a vehicle, comprising:

an inflator housing for storing a pressurized medium;

a first gas generating assembly including a first propellant that generates products of combustion including a first propellant gas;

a first initiator assembly for initiating ignition of said first propellant;

a second gas generating assembly including a second propellant that generates products of combustion including a second propellant gas, at least one of said first and second gas generating assemblies including a chamber closure member and said second gas generating assembly including a propellant cup and in which said chamber closure member is joined to a bottom of said propellant cup;

a second initiator assembly for initiating ignition of said second propellant;

an outlet assembly through which inflation gas, which includes at least one of the first propellant gas and the second propellant gas, passes into the inflatable in the vehicle; and

a control system operatively associated with said first and second initiator assemblies for controlling activation thereof;

wherein said first initiator assembly including a first passageway and said second initiator assembly includes a second passageway and in which said chamber closure member covers said first and second passageways and, when the vehicle is subject to a low impact event, said first initiator assembly is activated using said control system and, after a delay beginning with activation of said first initiator assembly, said second initiator assembly is activated using said control system.

13. A dual initiator inflator for providing inflation gas to an inflatable located in a vehicle, comprising:

an inflator housing for storing a pressurized medium;

a first gas generating assembly including a first propellant that generates products of combustion including a first propellant gas;

a first initiator assembly for initiating ignition of said first propellant;

a second gas generating assembly including a second propellant that generates products of combustion including a second propellant gas, said second gas generating assembly including a propellant cup in which said second propellant is contained and a closure cup disposed outwardly of said propellant cup and in which said closure cup prevents products of combustion from entering into said propellant cup which said first propellant is ignited and said second propellant is not ignited;

a second initiator assembly for initiating ignition of said second propellant;

an outlet assembly through which inflation gas, which includes at least one of the first propellant gas and the second propellant gas, passes into the inflatable in the vehicle; and

a control system operatively associated with aid first and second initiator assemblies for controlling activation thereof;

wherein, when the vehicle is subject to a low impact event, said first initiator assembly is activated using said control system and, after a delay beginning with activation of said first initiator assembly, said second initiator assembly is activated using said control system.

14. A dual initiator inflator for providing inflation gas to an inflatable located in a vehicle comprising:

an inflator housing for storing a pressurized medium;

a first gas generating assembly including a first propellant that generates products of combustion including a first propellant gas;

a first initiator assembly for initiating ignition of said first propellant;

a second gas generating assembly including a second propellant that generates products of combustion including a second propellant gas, said second gas generating assembly including a propellant cup in which said second propellant is contained and a closure cup disposed outwardly of said propellant cup and in which said closure cup is movable relative to said propellant cup when products of combustion are generated due to ignition of said second propellant;

second initiator assembly for initiating ignition of said second propellant;

an outlet assembly through which inflation gas, which includes at least one of the first propellant gas and the second propellant gas, passes into the inflatable in the vehicle; and

a control system operatively associated with said first and second initiator assemblies for controlling activation thereof;

wherein, when the vehicle is subject to a low impact event, said first initiator assembly is activated using said control system and, after a delay beginning with activation of said first initiator assembly, said second initiator assembly is activated using said control system.

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

said propellant cup includes an opening that underlies portions of said closure cup.

16. A method for inflating an inflatable in a vehicle using an inflator and a control system, comprising:

detecting an impact event to which the vehicle is subjected using said control system, said impact event including at least one of a low impact event and a high impact event, when a low impact event is detected the inflatable is inflated to a first pressure and when a high impact event is detected the inflatable is inflated to a second pressure, with said second pressure being greater than said first pressure;

igniting firstly a first propellant using a first initiator when said low impact event is detected;

generating a first propellant gas using said first propellant when said low impact event is detected;

receiving said first propellant gas in the inflatable when said low impact event is detected;

delaying for a time interval after said igniting firstly step when said low impact event is detected;

igniting secondly a second propellant using a second initiator after said delaying step when said low impact is detected, wherein products of combustion are generated from said second propellant due to said igniting secondly step and in which substantially all the propellant gas received in the inflatable is from said first propellant and substantially no propellant gas is received in the inflatable from said second propellant;

igniting said first propellant and said second propellant at substantially the same time using said first initiator and said second initiator, respectively, when said high impact event is detected;

generating said first propellant gas and a second propellant gas using said first and second propellants, respectively when said high impact event is detected; and

receiving said first a second propellant gases in the inflatable when said high impact event is detected.

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

said time interval is greater than about 100 msec.

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

said step of generating said first propellant gas using said first propellant when a low impact event is detected includes outputting said first propellant gas radially from an outlet member of a first gas generating assembly that includes said first propellant.

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

said step of generating said first propellant gas and said second propellant gas when said high impact event is detected includes outputting products of combustion front an open end of a second gas generating assembly that includes said second propellant and in which said open end was open before said step of igniting said first and second propellants at substantially the same time.

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

said step of generating said first propellant gas using said first propellant when said low impact event is detected includes generating said first propellant gas in a first chamber containing said first propellant while propellant gas is not generated in a second chamber containing said second propellant and in which said second chamber is inwardly located relative to said first chamber.

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

each of said first and second initiators is offset from a center axis of the inflator.

22. A method for inflating an inflatable in a vehicle using an inflator and a control system, comprising:

detecting a low impact event to which the vehicle is subjected using said control system;

igniting firstly a first propellant using a first initiator, said igniting firstly step including using a first passageway between said first initiator and a first chamber to cause said first propellant located in said first chamber to ignite upon activation of said first initiator, said first passageway being offset from a longitudinal, center axis of said first initiator;

generating a first propellant gas using said first propellant;

receiving said first propellant gas in the inflatable;

delaying for a time interval after said igniting firstly step; and

igniting secondly a second propellant using a second initiator after said delaying step.

23. A method for inflating an inflatable in a vehicle using an inflator and a control system, comprising:

detecting a low impact event to which the vehicle is subjected using said control system;

igniting firstly a first propellant using a first initiator;

generating a first propellant gas using said first propellant;

receiving said first propellant gas in the inflatable;

delaying for a time interval after said igniting firstly step; and

igniting secondly a second propellant using a second initiator after said delaying step, said igniting secondly step including using a second passageway between said second initiator and a second chamber to cause said second propellant in said second chamber to ignite upon activation of said second initiator, said second passageway being offset from a longitudinal, center axis of said second initiator.

24. A method for inflating au inflatable in a vehicle using an inflator and a control system, comprising:

detecting a low impact event to which the vehicle is subjected using said control system;

igniting firstly a first propellant using a first initiator;

generating a first propellant gas using said first propellant;

receiving said first propellant gas in the inflatable;

delaying for a time interval after said igniting firstly step; and

igniting secondly a second propellant using a second initiator after said delaying step, said igniting secondly step including motoring a closure cup using products of combustion from said second propellant after ignition thereof.

25. A method for inflating an inflatable in a vehicle using an inflator and a control system, comprising:

detecting a low impact event to which the vehicle is subjected using said control system;

igniting firstly a first propellant using a first initiator;

generating a first propellant gas using said first propellant;

receiving said first propellant gas in the inflatable;

delaying for a time interval after said igniting firstly step; and

igniting secondly a second propellant using a second initiator after said delaying step and using a closure cup to prevent entry of products of combustion from said first propellant to said second propellant.