Hybrid inflator with foam as a fuel

Patent metadata

Field	Value
Publication number	US-10207671-B2
Application number	US-201615355165-A
Country	US
Kind code	B2
Filing date	Nov 18, 2016
Priority date	Nov 18, 2016
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

An inflator (10) is actuatable to provide inflation fluid for inflating an inflatable vehicle occupant protection device. The inflator (10) includes a volume of stored gas and a propellant (52) that is ignitable to undergo a reaction that produces reaction products. The reaction products include heat and gas that mix with the stored gas to produce a mixture of inflation fluid. The inflator (10) is configured to discharge the inflation fluid to inflate the protection device. The propellant (52) comprises an open cell foam fuel propellant (140). The reaction includes a combustion reaction in which the foam fuel propellant (140) reacts with a gas oxidizer comprising oxygen to produce heat and gas reaction products that mix with the stored gas.

First claim

Having described the invention, we claim the following:

1. An inflator that is actuatable to provide inflation fluid for inflating an inflatable vehicle occupant protection device, the inflator comprising:
a volume of stored gas stored at a pressure of al least 5000 psi; and
a propellant that is ignitable to undergo a reaction that produces reaction products, the reaction products comprising heat and gas that mix with the stored gas to produce a mixture of inflation fluid, the inflator being configured to discharge the inflation fluid to inflate the protection device,
wherein the propellant comprises an open cell foam fuel propellant, the reaction comprising a combustion reaction in which the foam fuel propellant reacts with a gas oxidizer comprising oxygen to produce heat and gas reaction products that mix with the stored gas.

2. The inflator recited in claim 1 , wherein the propellant further comprises a pyrotechnic propellant comprising a chemical composition, the reaction further comprising a self-sustaining chemical reaction in which a fuel component of the chemical composition reacts with an oxidizer component of the chemical composition to produce heat and gas reaction products that mix with the stored gas.

3. The inflator recited in claim 1 , wherein the foam fuel propellant comprises a foam polyhydrocarbon, carbonhydretes or polyolefin material.

4. The inflator recited in claim 1 , wherein the foam fuel propellant comprises at least one of a polyether, polyester, polystyrene, polypropylene, polyethylene, and polyurethane material.

5. The inflator recited in claim 1 , wherein the propellant further comprises reaction modifiers comprising at least one of aluminum, titanium, silicon, magnesium, aluminum metal oxides, titanium metal oxides, silicon metal oxides, magnesium metal oxides, aluminum alloys, titanium alloys, silicon alloys, magnesium alloys, an magnesium-aluminum alloy, all in at least one of granular, flaked, and powdered form, boron hydrides, and soot.

6. The inflator recited in claim 1 , further comprising a housing defining a reaction chamber for containing the propellant and the gas oxidizer, and a pressure chamber for containing the stored gas, the reaction chamber and the pressure chamber being separated by a first closure member that is rupturable in response to actuation of the inflator to permit the reaction products produced by the propellant to mix with the stored gas in the pressure chamber.

7. The inflator recited in claim 6 , further comprising an igniter that is actuatable to ignite the propellant in the reaction chamber, the igniter being configured to produce a shock wave when actuated, and wherein the foam fuel propellant in the reaction chamber is configured to permit the shock wave to propagate through the reaction chamber without a significant loss of intensity, the shock wave acting on and rupturing the first closure member separating the reaction chamber from the pressure chamber, thereby allowing the reaction products to enter the pressure chamber and mix with the stored gas.

8. The inflator recited in claim 7 , further comprising an inflator outlet portion positioned at an end of the pressure chamber opposite the first closure member, and a second closure member that closes the inflator outlet, wherein the shock wave produced by actuation of the ignitor is configured to also propagate through the pressure chamber and rupture the second closure member after rupturing the first closure member.

9. The inflator recited in claim 8 , further comprising an inflator outlet portion positioned at an end of the pressure chamber opposite the first closure member, and a second closure member that closes the inflator outlet, wherein the first closure member is configured to produce a shock wave in response to being ruptured, the shock wave produced by rupture of the first closure member propagating through the pressure chamber and rupturing the second closure member.

10. The inflator recited in claim 6 , wherein the first closure member provides a gas permeable seal between the reaction chamber and the pressure chamber.

11. The inflator recited in claim 1 , wherein the propellant comprises foam fuel propellant only.

12. The inflator recited in claim 1 , wherein the foam fuel propellant is compressed in a reaction chamber or the inflator and conforms to the inflator structures in the reaction chamber.

13. The inflator recited in claim 12 , wherein the foam fuel propellant does not fill the entire reaction chamber, and wherein the foam fuel propellant is held in place in the reaction chamber by at least one of adhesives and a frictional engagement resulting from the foam being compressed within the reaction chamber.

14. The inflator recited in claim 11 , wherein the volume of the foam fuel propellant is selected to tailor the output of the inflator without adjusting the structure of the inflator to accommodate the selected volume.

15. The inflator recited in claim 11 , wherein the foam fuel propellant fills an entire reaction chamber of the inflator.

16. The inflator recited in claim 11 , wherein the foam fuel propellant comprises one or more bores that extend through the foam fuel propellant.

17. The Inflator recited in claim 11 , wherein the foam fuel propellant comprises a single mass of foam fuel propellant material.

18. The inflator recited in claim 11 , wherein the foam fuel propellant comprises a plurality of foam fuel propellant bodies.

19. The inflator recited in claim 18 , wherein different ones of the foam fuel propellant bodies are made of different types of foam fuel propellant material.

20. The inflator recited in claim 19 , wherein the foam fuel propellant bodies have at least one of shapes and colors that correspond to the type of foam fuel propellant material from which the bodies are constructed.

21. The inflator recited in claim 1 , wherein the stored gas, the propellant, and the oxidizing gas are all stored in a single chamber in the inflator, wherein the stored gas and the oxidizing gas comprise a gas mixture including oxygen and at least one inert gas.

22. The inflator recited in claim 2 , wherein the pyrotechnic propellant comprises a plurality of pyrotechnic, propellant rings arranged axially in a stacked configuration in the inflator.

23. The inflator recited in claim 22 , wherein the pyrotechnic propellant rings comprise aligned central openings, the foam fuel propellant comprising a cylindrical portion that extends through the aligned central openings.

24. The Inflator recited in claim 22 , wherein the pyrotechnic propellant rings are spaced from each other axially in the inflator, and wherein the foam fuel propellant comprises disc shaped spacers positioned between the pyrotechnic propellant rings.

25. The inflator recited in claim 22 , wherein the pyrotechnic propellant rings are spaced from each other axially in the inflator and comprise aligned central openings, and wherein the foam fuel propellant comprises disc shaped spacers positioned between the pyrotechnic propellant rings and cylindrical portions that extend through the aligned central openings.

26. The inflator recited in claim 2 , wherein the tom fuel propellant comprises one or more bores that extend through the foam fuel propellant, and wherein the propellant comprises a plurality of pyrotechnic propellant tablets that are supported in the bores through an interference fit in which the tablets de

Assignees

• Trw Airbag Sys Gmbh

Inventors

• Last Detlef
• Rolf Ruckdeschel

Classifications

• B60R21/2644

  using only solid reacting substances, e.g. pellets, powder · CPC title

• C06D5/10

  by reaction of solids with liquids · CPC title

• B60R21/272 Primary

  with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators · CPC title

• B60R21/274

  characterised by means to rupture or open the fluid source · CPC title