Autoignition of a fluid fueled inflator

• US 5,494,312 A
• Filed: 02/02/1995
• Issued: 02/27/1996
• Est. Priority Date: 05/31/1994
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Rink, Karl K.
• Primary Examiner(s): Dickson, Paul N.
• Application Number:
  US08/382,559
• Time in Patent Office: 390 Days
• Field of Search: 280/737, 280/741, 280/740, 280/736, 280/742, 222/3, 222/5
• US Class Current: 280/737
• CPC Class Codes: B60R 2021/26064 characterised by auto-ignition means
• 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

An apparatus and method for autoignition operation of a fluid fueled inflator used in inflating a vehicle occupant restraint. The inflator device in addition to a fluid fuel, also contains stored pressurized gas.

Claims

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

a fluid fuel storage element storing at least one fuel in the form of a fluid and free of combustion oxidant,

a first chamber in fluid communication with said fluid fuel storage element upon opening of said fluid fuel storage element, said first chamber including at least one gas exit opening and having sealing means normally closing said gas exit opening, and wherein, in normal operation, the at least one fuel and at least one stored oxidant are burned to produce combustion products including hot combustion gas, with the combustion of the at least one fuel and the at least one stored oxidant increasing the temperature and pressure within said first chamber, said first chamber sealing means adapted to open when a predetermined increase in pressure within said first chamber is realized,

whereby, in normal operation, at least a portion of said 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 sealing means, with said second chamber including at least one gas exit port and having sealing means normally closing said gas exit port, in normal operation said hot combustion gas expelled from said first chamber mixing with said pressurized stored gas to produce inflation gas, the mixing of said hot combustion gas with said pressurized stored gas increasing the temperature and pressure within said second chamber, said second chamber sealing means adapted to open when a predetermined increase in pressure within said second chamber is realized after said hot combustion gas expelled from said first chamber mixes with said pressurized stored gas to produce said inflation gas,

whereby, in normal operation, at least a portion of said inflation gas is expelled from said second chamber to inflate said device, and

initiator means for initiating the burning of the at least one fuel and the at least one oxidant in normal operation,

wherein under autoignition operation, at a predetermined first temperature greater than the ambient temperature range to which said inflation apparatus is normally subjected, said fluid fuel storage element opens and at least a portion of the at least one fuel contacts an oxidant in said first chamber, with the at least one fuel being characterized in igniting when exposed to the oxidant at a predetermined second temperature, greater than the ambient temperature range to which said inflation apparatus is normally subjected.

2. The apparatus of claim 1 wherein the fuel in the form of a fluid includes a liquid form.

3. The apparatus of claim 1 wherein the fuel in the form of a fluid comprises a multi-phase combination of liquid and finely divided solid.

4. The apparatus of claim 1 wherein the fuel in the form of a fluid is a hydrocarbon-based fuel.

5. The apparatus of claim 1 wherein the fuel in the form of a fluid includes ethyl alcohol.

6. The apparatus of claim 1 wherein the fuel in the form of a fluid includes propyl alcohol.

7. The apparatus of claim 1 wherein the fuel in the form of a fluid includes at least one C₂ -C₄ alkane.

8. The apparatus of claim 1 wherein, under autoignition operation, the oxidant with which the at least one fuel is burned comprises the at least one stored oxidant.

9. The apparatus of claim 1 where in, under autoignition operation, the oxidant with which the at least one fuel is burned comprises air.

10. The apparatus of claim 1 wherein said fluid fuel storage element stores a mixture comprising a primary fuel and an autoignition enhancing material.

11. The apparatus of claim 10 wherein the autoignition enhancing material is a paraffinic fuel selected from the group consisting of n-octane, n-heptane and n-hexane.

12. The apparatus of claim 10 wherein the autoignition enhancing material is a petroleum distillates selected from the group consisting of diesel fuel, JP-4, and gasoline.

13. The apparatus of claim 10 wherein the autoignition enhancing material is a mineral oil.

14. The apparatus of claim 1 wherein the predetermined second temperature is at least as great as the predetermined first temperature.

15. The apparatus of claim 1 wherein the predetermined first temperature and the predetermined second temperature are substantially the same.

16. The apparatus of claim 1 wherein the predetermined first temperature is greater than the predetermined second temperature.

17. The apparatus of claim 1 wherein the predetermined first temperature is less than the predetermined second temperature.

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

a liquid fuel storage element storing at least one liquid fuel free of combustion oxidant,

a first chamber in fluid communication with said liquid fuel storage element upon opening of said liquid fuel storage element, said first chamber including at least one gas exit opening and having sealing means normally closing said gas exit opening, and wherein, in normal operation, the at least one liquid fuel and at least one stored oxidant are burned to produce combustion products including hot combustion gas, with the combustion of the at least one liquid fuel and the at least one stored oxidant increasing the temperature and pressure within said first chamber, said first chamber sealing means adapted to open when a predetermined increase in pressure within said first chamber is realized,

whereby, in normal operation, at least a portion of said 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 sealing means, with said second chamber including at least one gas exit port and having sealing means normally closing said gas exit port, in normal operation said hot combustion gas expelled from said first chamber mixing with said pressurized stored gas to produce inflation gas, the mixing of said hot combustion gas with said pressurized stored gas increasing the temperature and pressure within said second chamber, said second chamber sealing means adapted to open when a predetermined increase in pressure within said second chamber is realized after said hot combustion gas expelled from said first chamber mixes with said pressurized stored gas to produce said inflation gas,

whereby, in normal operation, at least a portion of said inflation gas is expelled from said second chamber to inflate said device, and

initiator means for initiating the burning of the at least one liquid fuel and the at least one oxidant in normal operation,

wherein under autoignition operation, at a predetermined first temperature greater than the ambient temperature range to which said inflation apparatus is normally subjected, said liquid fuel storage element opens and at least a portion of the at least one liquid fuel contacts an oxidant in said first chamber, with the at least one liquid fuel being characterized in igniting when exposed to the oxidant at a predetermined second temperature at least as great as the predetermined first temperature.

19. The apparatus of claim 18 wherein, under autoignition operation, the oxidant with which the at least one fluid fuel is burned comprises the at least one stored oxidant.

20. The apparatus of claim 18 wherein, under autoignition operation, the oxidant with which the at least one fluid fuel is burned comprises air.

21. The apparatus of claim 18 wherein said fluid fuel storage element stores a mixture comprising a primary fuel and an autoignition enhancing material.

22. A method for autoignition operation of an apparatus for inflating an inflatable device, wherein the apparatus includes a fluid fuel storage element storing at least one fuel in the form of a fluid and free of combustion oxidant, with the apparatus also including a closed combustion chamber in fluid communication with the fluid fuel storage element upon opening of the fluid fuel storage element, said method comprising the step of:

heating the inflation apparatus whereby at a predetermined first temperature greater than the ambient temperature range to which the inflation apparatus is normally subjected, the fluid fuel storage element opens and at least a portion of the fuel contacts an oxidant in the closed combustion chamber, with the fuel igniting when exposed to the oxidant at a predetermined second temperature, greater than the ambient temperature range to which the inflation apparatus is normally subjected to produce combustion products, with the closed combustion chamber opening when a predetermined increase in pressure within the first chamber is realized.

23. The method of claim 22 wherein the predetermined second temperature is at least as great as the predetermined first temperature.

26. The method of claim 22 wherein the predetermined first temperature is less than the predetermined second temperature.

27. A method of autoignition operation of an apparatus for inflating an inflatable device, wherein the apparatus includes a fluid fuel storage element storing at least one fuel in the form of a fluid and free of combustion oxidant, said method comprising the steps of:

heating the inflation apparatus whereby at a predetermined first temperature greater than the ambient temperature range to which the inflation apparatus is normally subjected, the fluid fuel storage element opens and at least a portion of the at least one fuel contacts an oxidant, with the at least one fuel igniting when exposed to the oxidant at a predetermined second temperature, greater than the ambient temperature range to which said inflation apparatus is normally subjected,

burning the at least one fuel with the oxidant in a first sealed chamber to produce combustion products including hot combustion gas, 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,

opening the first chamber sealing means to expel the hot combustion gas from the first chamber into a second chamber containing a supply of pressurized stored gas,

mixing the expelled hot combustion gas with the pressurized stored gas in the second chamber to produce inflation gas, 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, and

opening the second chamber port sealing means to expel the inflation gas from the second chamber to inflate the inflatable safety device.

28. A method of autoignition operation of an apparatus for inflating an inflatable device, wherein the apparatus includes a fluid fuel storage element storing at least one fuel in the form of fluid and free of combustion oxidant, said method comprising the step of:

heating the inflation apparatus whereby at a predetermined first temperature greater than the ambient temperature range to which the inflation apparatus is normally subjected, the fluid fuel storage element opens and at least a portion of the at least one fuel contacts an oxidant, with the at least one fuel igniting when exposed to the oxidant at a predetermined second temperature, greater than the ambient temperature range to which the inflation apparatus is normally subjected, wherein the inflation apparatus also includes;

a first chamber containing a supply of stored oxidant, the first chamber in fluid communication with the fluid fuel storage element upon opening of the fluid fuel storage element, the first chamber including at least one gas exit opening and having sealing means normally closing the gas exit opening, and

a second chamber containing a supply of pressurized stored gas, the second chamber in fluid communication with the first chamber upon the opening of the gas exit opening sealing means, with the second chamber including at least one gas exit port and having sealing means normally closing the gas exit port,

wherein said method, prior to the igniting of the at least one fuel, additionally comprises the steps of;

opening the second chamber sealing means to vent at least a portion of the pressurized stored gas,

followed by, opening the first chamber sealing means to vent at least a portion of the stored oxidant to vent through the open second chamber.

29. A method for autoignition operation of an apparatus for inflating an inflatable device, wherein the apparatus includes a fluid fuel storage element storing at least one fluid fuel in the form of a fluid and free of combustion oxidant, with the apparatus also including a closed combustion chamber in fluid communication with the fluid fuel storage element upon opening of the fluid fuel storage element, said method comprising the steps of:

opening the closed combustion chamber,

followed by opening the fluid fuel storage element when the inflation apparatus is heated to a predetermined first temperature greater than the ambient temperature range to which the inflation apparatus is normally subjected whereby at least a portion of the fuel contacts an oxidant in the combustion chamber, with the fuel igniting when exposed to the oxidant at a predetermined second temperature, greater than the ambient temperature range to which the inflation apparatus is normally subjected.

24. The method of claim 32 wherein the predetermined first temperature and the predetermined second temperature are substantially the same.

25. The method of claim 32 wherein the predetermined first temperature is greater than the predetermined second temperature.

30. The method of claim 29 wherein the predetermined second temperature is at least as great as the predetermined first temperature.

31. The method of claim 29 wherein the predetermined first temperature and the predetermined second temperature are substantially the same.

32. The method of claim 29 wherein the predetermined first temperature is greater than the predetermined second temperature.

33. The method of claim 29 wherein the predetermined first temperature is less than the predetermined second temperature.