Fuel containment for fluid fueled airbag inflators

• US 5,803,492 A
• Filed: 09/30/1996
• Issued: 09/08/1998
• Est. Priority Date: 05/31/1994
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Miller, Harry W., Smith, Bradley W., Lang, Gregory J., Green, David J., Rink, Karl K., Ravenberg, Michael J., Pierotti, L. John, Moore, Walter A.
• Primary Examiner(s): English, Peter C.
• Application Number:
  US08/723,796
• Time in Patent Office: 708 Days
• Field of Search: 280/736, 280/737, 280/740, 280/741, 280/742, 137/68.13, 137/68.19, 137/68.23, 137/68.25, 222/3, 222/5, 102/530, 102/531
• US Class Current: 280/737
• 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 21/272 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

Apparatus for inflating an inflatable device, methods for inflating an inflatable safety device and a method of manufacturing an apparatus for inflating an inflatable device are provided having a fuel containment assembly to contain a fuel in the form of a fluid. The fuel, upon proper initiation, is burned to produce gas used in the inflation of the inflatable device.

Claims

1. An apparatus for inflating an inflatable device, said apparatus comprising:

a closed first chamber wherein at least one fuel in the form of a fluid is burned to produce combustion products, with said first chamber openable at predetermined conditions to permit release of the combustion products;

a fuel containment assembly including a capsule having a unitary fixed outer wall defining an enclosed storage volume, with the storage volume containing at least a supply of the at least one fuel in the form of a fluid prior to installation of the capsule in the apparatus, with the capsule adapted to open at predetermined operating conditions to be in fluid communication with said first chamber; and

an initiator to initiate burning of the at least one fuel in said first chamber.

2. The apparatus of claim 1 wherein the at least one fuel comprises a fluid in the form of a gas, liquid, finely divided solid or a combination thereof.

3. The apparatus of claim 1 wherein the at least one fuel comprises a fluid in the form of a gas.

4. The apparatus of claim 1 wherein the at least one fuel comprises a fluid in the form of a liquid.

5. The apparatus of claim 1 wherein the at least one fuel comprises a fluid in the form of a finely divided solid.

6. The apparatus of claim 1 wherein the at least one fuel is stored free of combustion oxidant within said fuel containment assembly.

7. The apparatus of claim 1 wherein the at least one fuel and an oxidant are stored together within said fuel containment assembly as a single material.

8. The apparatus of claim 7 wherein the single material comprises a hydroxyl ammonium nitrate-based liquid monopropellant.

9. The apparatus of claim 1 wherein the capsule is formed from plastic.

10. The apparatus of claim 1 wherein the first chamber contains an oxidizing environment and the capsule is fabricated of a material at least in part consumable in the oxidizing environment of the first chamber.

11. The apparatus of claim 1 wherein the outer wall of the capsule is shaped to form a profile adapted to correspond to the external shape of said initiator.

12. The apparatus of claim 1 wherein the capsule includes integral therewith a retainer adapted to permit direct attachment of the capsule within the apparatus.

13. The apparatus of claim 1 wherein the capsule has been pre-weakened by selectively reducing the thickness of the outer wall.

14. The apparatus of claim 13 wherein said selective reduction in the thickness of the capsule outer wall comprises at least one axially extending score.

15. The apparatus of claim 13 wherein said selective reduction in the thickness of the capsule outer wall comprises at least one radially extending score.

16. The apparatus of claim 13 wherein said selective reduction in the thickness of the capsule outer wall comprises at least one cylindrical helix axially extending score.

17. The apparatus of claim 13 wherein said selective reduction in the thickness of the capsule outer wall comprises at least one non-continuous score.

18. The apparatus of claim 13 wherein said selective reduction in the thickness of the capsule outer wall comprises at least one multiple depth score.

19. The apparatus of claim 1 wherein the capsule includes at least one stiffening feature.

20. The apparatus of claim 19 wherein the capsule outer wall has an inner surface and the stiffening feature comprises a ring adjacent the inner surface of the capsule outer wall.

21. The apparatus of claim 1 wherein said fuel containment assembly is adapted to moderate the rate of introduction of the fuel into the first chamber dependent on selected design parameters including sizing of said initiator, fracturability of the capsule and selection, amount and fill fraction of the fuel.

22. The apparatus of claim 1 wherein said fuel containment assembly is adapted to self-compensate for the influence of ambient temperature.

23. The apparatus of claim 1 wherein the capsule outer wall has an external surface and said fuel containment assembly additionally comprises a housing adjacent at least a portion of the capsule outer wall external surface.

24. The apparatus of claim 23 wherein said housing is fabricated of metal.

25. The apparatus of claim 23 wherein said housing is fabricated of a material impervious to the at least one fuel.

26. The apparatus of claim 23 wherein said housing comprises a screen material.

27. The apparatus of claim 23 wherein said housing comprises an outer wall and the housing outer wall has been pre-weakened by selectively reducing the thickness of the housing outer wall.

28. An apparatus for inflating an inflatable device, said apparatus comprising:

a closed first chamber wherein at least one fuel in the form of a fluid is burned to produce combustion products, said first chamber openable at predetermined conditions to permit release of the combustion products; and

a fuel containment assembly including;

a closed housing having an outer wall and containing, free of combustion oxidant, a supply of the at least one fuel in the form of a fluid with the outer wall impervious to the at least one fuel, with the housing adapted to open at predetermined operating conditions to be in fluid communication with said first chamber;

the assembly also having, along a second wall of the housing, an initiator to initiate burning of the at least one fuel in said first chamber.

29. The apparatus of claim 28 wherein the at least one fuel comprises a fluid in the form of a gas, liquid, finely divided solid or a combination thereof.

30. The apparatus of claim 28 wherein the at least one fuel comprises a fluid in the form of a gas.

31. The apparatus of claim 28 wherein the at least one fuel comprises a fluid in the form of a liquid.

32. The apparatus of claim 28 wherein the at least one fuel comprises a fluid in the form of a finely divided solid.

33. The apparatus of claim 28 wherein the housing is formed from metal.

34. The apparatus of claim 28 wherein the housing has been pre-weakened by selectively reducing the thickness of the outer wall.

35. The apparatus of claim 34 wherein said selective reduction in the thickness of the housing outer wall comprises at least one axially extending score.

36. The apparatus of claim 34 wherein said selective reduction in the thickness of the housing outer wall comprises at least one radially extending score.

37. The apparatus of claim 34 wherein said selective reduction in the thickness of the housing outer wall comprises at least one cylindrical helix axially extending score.

38. The apparatus of claim 34 wherein said selective reduction in the thickness of the housing outer wall comprises at least one non-continuous score.

39. The apparatus of claim 34 wherein said selective reduction in the thickness of the housing outer wall comprises at least one multiple depth score.

40. The apparatus of claim 28 wherein the housing includes at least one stiffening feature.

41. The apparatus of claim 40 wherein the housing outer wall has an inner surface and the stiffening feature comprises a ring adjacent the inner surface of the housing outer wall and adapted to increase the external load capacity of the housing.

42. The apparatus of claim 28 wherein said fuel containment assembly is adapted to moderate the rate of introduction of the fuel into the first chamber dependent on selected design parameters including sizing of said initiator, fracturability of the housing and selection, amount and fill fraction of the fuel.

43. The apparatus of claim 28 wherein said fuel containment assembly is adapted to self-compensate for the influence of ambient temperature.

46. The apparatus of claim 43 wherein the at least one fuel and an oxidant are stored together within said fuel containment assembly as a single material.

47. The apparatus of claim 46 wherein the single material comprises a hydroxyl ammonium nitrate-based liquid monopropellant.

48. The apparatus of claim 43 wherein the capsule has been pre-weakened by selectively reducing the thickness of the outer wall.

49. The apparatus of claim 48 wherein said selective reduction in the thickness of the capsule outer wall comprises at least one multiple depth score.

44. An apparatus for inflating an inflatable device, said apparatus comprising:

a closed fuel containment assembly including a capsule having a unitary fixed outer wall and defining an enclosed storage volume, with the storage volume containing, prior to installation of the capsule in the apparatus, contents including at least a supply of at least one fuel in the form of a fluid, with said fuel containment assembly adapted to open at predetermined operating conditions;

a first chamber in fluid communication with at least a portion of the supply of the at least one fuel from the capsule upon opening of said fuel containment assembly, wherein the at least one fuel is burned to produce combustion products including hot combustion gas, the combustion of the at least one fuel increasing the temperature and pressure within said first chamber with said first chamber adapted to open when a predetermined increase in pressure within said first chamber is realized, whereby at least a portion of the hot combustion gas is expelled from said first chamber;

a second chamber containing a supply of pressurized stored gas, said second chamber in fluid communication with said first chamber upon the opening of said first chamber with the hot combustion gas expelled from said first chamber mixing with the pressurized stored gas to produce inflation gas, said second chamber adapted to open when a predetermined increase in pressure within said second chamber is realized after the hot combustion gas expelled from said first chamber mixes with the pressurized stored gas to produce the inflation gas, whereby at least a portion of the inflation gas is expelled from said second chamber to inflate the device; and

an initiator to initiate burning of at least a portion of the at least one fuel in said first chamber.

45. The apparatus of claim 44 wherein the at least one fuel is stored free of combustion oxidant within said fuel containment assembly.

50. The apparatus of claim 44 wherein said fuel containment assembly is adapted to moderate the rate of introduction of the fuel into the first chamber dependent on selected design parameters including sizing of said initiator, fracturability of the capsule and selection, amount and fill fraction of the fuel.

51. The apparatus of claim 44 wherein said fuel containment assembly is adapted to self-compensate for the influence of ambient temperature.

52. The apparatus of claim 44 wherein the capsule outer wall has an external surface and said fuel containment assembly additionally comprises a housing adjacent at least a portion of the capsule outer wall external surface.

53. The apparatus of claim 52 wherein the housing comprises a screen material.

54. The apparatus of claim 52 wherein the housing comprises an outer wall and wherein the housing outer wall has been pre-weakened by selectively reducing the thickness of the housing outer wall.

55. An apparatus for inflating an inflatable device, said apparatus comprising:

a fuel containment assembly including a closed housing having an outer wall and containing, free of combustion oxidant, contents including a supply of at least one fuel in the form of a fluid, the outer wall being impervious to the at least one fuel, with the housing outer wall adapted to open at predetermined operating conditions;

a first chamber in fluid communication with said fuel containment assembly upon opening of the housing outer wall, wherein at least a portion of the supply of the at least one fuel is burned to produce combustion products including hot combustion gas, the combustion of the at least one fuel increasing the temperature and pressure within said first chamber with said first chamber adapted to open when a predetermined increase in pressure within said first chamber is realized, whereby at least a portion of the hot combustion gas is expelled from said first chamber;

a second chamber containing a supply of pressurized stored gas, said second chamber in fluid communication with said first chamber upon the opening of said first chamber with the hot combustion gas expelled from said first chamber mixing with the pressurized stored gas to produce inflation gas, said second chamber adapted to open when a predetermined increase in pressure within said second chamber is realized after the hot combustion gas expelled from said first chamber mixes with the pressurized stored gas to produce the inflation gas, whereby at least a portion of the inflation gas is expelled from said second chamber to inflate the device; and

an initiator to initiate the burning of the at least one fuel in said first chamber.

56. The apparatus of claim 55 wherein the housing has been pre-weakened by selectively reducing the thickness of the outer wall.

57. The apparatus of claim 56 wherein said selective reduction in the thickness of the housing outer wall comprises at least one multiple depth score.

58. The apparatus of claim 55 wherein said fuel containment assembly is adapted to moderate the rate of introduction of the fuel into the first chamber dependent on selected design parameters including sizing of said initiator, fracturability of the housing and selection, amount and fill fraction of the fuel.

59. The apparatus of claim 55 wherein said fuel containment assembly is adapted to self-compensate for the influence of ambient temperature.

60. A method for inflating an inflatable safety device in a vehicle using an inflation apparatus, said method comprising the steps of:

opening at least one of;

a) a closed capsule having a unitary fixed outer wall defining an enclosed storage volume containing, prior to installation in the apparatus, at least a supply of at least one fuel in the form of a fluid, and

b) a closed fuel housing of a fuel containment assembly, the housing containing, free of combustion oxidant, at least a supply of at least one fuel in the form of a fluid prior to said opening,

with said opening resulting in a release of at least a portion of the supply of the at least one fuel into a first sealed chamber;

burning the released portion of the supply of the at least one fuel in the first sealed chamber to produce combustion products including hot combustion gas; and

releasing inflation gas comprising at least a portion of the combustion gas from the apparatus to inflate the inflatable safety device.

61. The method of claim 60 wherein prior to the release of the inflation gas, said method additionally comprises the step of:

mixing at least a portion of the hot combustion gas from the first chamber with a pressurized stored gas in a second chamber to produce the inflation gas.

62. The method of claim 61 wherein the first sealed chamber includes at least one gas exit opening normally closed by a sealing means, said burning increasing the temperature and pressure within the first chamber, with the first chamber sealing means opening when a predetermined increase in pressure within the first chamber is realized to expel the hot combustion gas from the first chamber into the second chamber, and

wherein the second chamber includes at least one gas exit port normally closed by a sealing means, said mixing increasing the temperature and pressure within the second chamber, with the second chamber port sealing means opening after the hot combustion gas expelled from the first chamber has mixed with the pressurized stored gas to produce the inflation gas and when a predetermined increase in pressure within the second chamber is realized, to expel the inflation gas from the second chamber to inflate the inflatable safety device.

63. The method of claim 60 wherein:

a) when opening the closed capsule, said opening comprises rupturing an outer wall of the closed capsule and

b) when opening the closed fuel housing, said opening comprises rupturing an outer wall of the closed fuel housing.

64. The method of claim 60 wherein the degree to which either the capsule or the housing, respectively, opens and the rate at which the fuel is released into the sealed first chamber is dependent on the ambient temperature at which the method is conducted.

65. A method of manufacturing an apparatus for inflating an inflatable device, said method comprising the steps of:

at least partially filling an enclosed storage volume in a capsule with a supply of least one fuel in the form of a fluid, the enclosed storage volume defined by a unitary fixed outer wall of the capsule and

loading the fuel-containing capsule into an apparatus subcombination including;

a closed first chamber in fluid communication with the fuel-containing capsule upon opening of the capsule, wherein the at least one fuel is burned to produce combustion products, the first chamber openable at predetermined conditions to permit release of the combustion products, and

an initiator to initiate burning in said first chamber of at least a portion of the supply of the at least one fuel.