Adaptive output, toroidal-shaped pyrotechnic inflator

• US 20040145166A1
• Filed: 01/24/2003
• Published: 07/29/2004
• Est. Priority Date: 01/24/2003
• Status: Active Grant

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Smith, Bradley W.
• Granted Patent: US 6,966,578 B2
• Time in Patent Office: Days
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/26094 characterised by fluid flow controlling valves
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

A toroidal-shaped adaptive output inflator is provided wherein the inflator includes a toroidal-shaped outer housing and an inner housing together defining an outer chamber and an inner chamber. A supply of gas-generating pyrotechnic material having a burn rate that is pressure dependent is contained within the outer chamber and at least a portion of the supply of gas-generating pyrotechnic material is reactable to generate a product gas. The inflator also includes a first plurality of apertures and a second plurality of apertures each formed in the inner housing, and each providing independent fluidic communication between the outer chamber and the inner chamber wherethrough at least a portion of the product gas can exit the outer chamber into the inner chamber. An output control device positioned within the inner chamber is movable or rotatable between a first or open position allowing fluidic communication between the outer chamber and the inner chamber through the first plurality of apertures and the second plurality of apertures, and a second or closed position at least partially obstructing fluidic communication between the outer chamber and the inner chamber through at least one of the first plurality of apertures. Also provided is a control assembly in operational control communication with the inflator and associated or related methods for adjusting inflation gas output from the inflator.

Claims

1. A toroidal-shaped adaptive output inflator comprising:

a toroidal-shaped outer housing;

an inner housing connected to said outer housing and together defining an outer chamber and an inner chamber;

a supply of gas-generating pyrotechnic material having a burn rate that is pressure dependent contained within said outer chamber and wherein at least a portion of said supply of gas-generating pyrotechnic material is reactable to produce a product gas;

a primary initiator in discharge communication with said outer chamber, and in operational initiation communication with said supply of gas-generating pyrotechnic material;

a first plurality of apertures and a second plurality of apertures each formed in said inner housing, and each providing independent fluidic communication between said outer chamber and said inner chamber; and

an output control device movable between a first position allowing fluidic communication between said outer chamber and said inner chamber through said first plurality of apertures and said second plurality of apertures, and a second position at least partially obstructing fluidic communication between said outer chamber and said inner chamber through at least one of said first plurality of apertures.

2. The toroidal-shaped adaptive output inflator of claim 1 further comprising a control initiator in discharge communication with said output control device effective to move said output control device between the first position and the second position.

3. The toroidal-shaped adaptive output inflator of claim 2 wherein said output control device includes a control cup disposed relative to said control initiator and moveable between the first position and the second position.

4. The toroidal-shaped adaptive output inflator of claim 1 wherein said first plurality of apertures and said second plurality of apertures each forms independent fluidic communication channels between said outer chamber and said inner chamber.

5. The toroidal-shaped adaptive output inflator of claim 1 wherein the pressure dependency of the burn rate of said supply of gas-generating pyrotechnical material, as represented by n in a burn rate expression:

r_b=k(P)ⁿ

where r_b is a burn rate of the gas-generating pyrotechnic material, k is a constant, P is a combustion pressure, and n is a slope of a linear regression line drawn through a log-log plot of burn rate versus pressure, is at least about 0.4.

6. The toroidal-shaped adaptive output inflator of claim 1 wherein said output control device includes a rotor valve selectively rotatable between the first position and the second position.

7. The toroidal-shaped adaptive output inflator of claim 6 wherein said rotor valve is operatively connected to a solenoid device.

8. The toroidal-shaped adaptive output inflator of claim 6 wherein said rotor valve is repeatedly rotatable between the first position and the second position.

9. The toroidal-shaped adaptive output inflator of claim 1 wherein said first plurality of apertures and said second plurality of apertures each are formed in a cylindrical wall formed by said inner housing.

10. The toroidal-shaped adaptive output inflator of claim 9 wherein said output control device is positioned within said inner chamber.

11. The toroidal-shaped adaptive output inflator of claim 9 wherein said cylindrical wall comprises at least one interfering projection limiting movement of said output control device in the second position.

12. A combination comprising:

a toroidal-shaped adaptive output inflator including a toroidal-shaped outer housing and an inner housing, containing a supply of gas-generating pyrotechnic material having a bum rate that is pressure dependent reactable to produce a product gas, said inflator including a first plurality of apertures and a second plurality of apertures each providing independent fluidic communication between an outer chamber and an inner chamber defined within said inflator; and

a control assembly in operational control communication with said inflator, and providing a reaction initiating signal to a primary initiator to initiate reaction of at least a portion of said supply of gas-generating pyrotechnic material and a control signal to effect movement of an output control device between a first position allowing fluidic communication between said outer chamber and said inner chamber through said first plurality of apertures and said second plurality of apertures, and a second position at least partially obstructing fluidic communication between said outer chamber and said inner chamber through at least one of said first plurality of apertures.

13. The combination of claim 12 wherein said output control device includes a control cup positioned within said inner chamber and moveable between the first position and the second position.

14. The combination of claim 12 wherein said output control device includes a rotor valve selectively rotatable between the first position and the second position.

15. The combination of claim 14 wherein said rotor valve is operatively connected to a solenoid device.

16. The combination of claim 14 wherein said rotor valve is repeatedly rotatable between the first position and the second position.

17. The combination of claim 12 wherein said control signal is provided to a control initiator to effect movement of a control cup between the first position and the second position.

18. The combination of claim 12 wherein said control signal is provided to a solenoid device to effect movement of a rotor valve between the first position and the second position.

19. A method for adaptively adjusting a mass flow rate of a product gas by controlling an internal combustion pressure in a toroidal-shaped inflator comprising a toroidal-shaped outer housing and an inner housing connected to the outer housing and together defining an outer chamber and an inner chamber, and a supply of gas-generating pyrotechnic material contained within the outer chamber having a burn rate that is pressure dependent, at least a portion of the supply of gas-generating pyrotechnic material reactable to produce the product gas, the method comprising:

at least partially selectively obstructing fluidic communication between the outer chamber and the inner chamber through at least one of a first plurality of apertures and a second plurality of apertures each formed in the inner housing, and each providing independent fluidic communication between the outer chamber and the inner chamber.

20. The method of claim 19 wherein a control cup disposed relative to a control initiator is moveable between a first position allowing fluidic communication between the outer chamber and the inner chamber through the first plurality of apertures and the second plurality of apertures, and a second position wherein the control cup at least partially obstructs fluidic communication between the outer chamber and the inner chamber through at least one of the first plurality of apertures.

21. The method of claim 19 wherein a rotor valve is selectively rotatable between an open position allowing fluidic communication between the outer chamber and the inner chamber through the first plurality of apertures and the second plurality of apertures, and a closed position at least partially obstructing fluidic communication between the outer chamber and the inner chamber through at least one of the first plurality of apertures.

22. The method of claim 21 wherein said rotor value is operatively connected to a solenoid device.