Gas generating system

• US 20060005734A1
• Filed: 06/27/2005
• Published: 01/12/2006
• Est. Priority Date: 06/28/2004
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: TK Holdings Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: McCormick, David M.
• Granted Patent: US 7,814,838 B2
• Time in Patent Office: Days
• US Class Current: 102/530
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

A gas generating system (10) including a baffle system (42) for modifying the temperature and pressure of a gas generated by the system, and to remove particulates from the gas. The gas generating system includes a first combustion chamber (34a), a second combustion chamber (36a), and the baffle system (42) adjacent both the first and second combustion chambers so as to enable fluid communication with the combustion chambers upon activation of the gas generating system. In another aspect of the present invention, a baffle system (42) is provided including a first end plate (44) having an opening (44b) formed therein for enabling fluid communication with a first fluid source (34a), a second end plate (46) having an opening (46b) formed therein for enabling fluid communication with a second fluid source (36a), and a sequence of baffle elements (48) extending between the first and second end plates. A first baffle element (48a) of the sequence of baffle elements defines a chamber (60) for receiving therein a fluid through the openings in the first and second end plates. Each additional baffle element in the sequence of baffle elements is spaced outwardly apart from a preceding baffle element in the sequence of baffle elements. In another aspect of the invention, a method is provided for producing, in a gas generating system, a gas having a pressure within a predetermined pressure range and a temperature within a predetermined temperature range. In another aspect of the present invention, a vehicle occupant protection system is provided.

Claims

1. A gas generating system comprising:

a first combustion chamber;

a second combustion chamber; and

a baffle system positioned adjacent both the first and second combustion chambers so as to enable fluid communication with the first combustion chamber and the second combustion chamber upon activation of the gas generating system.

2. The gas generating system of claim 1 wherein the baffle system is adapted for providing a tortuous flow path for a fluid flowing through the baffle system.

3. The gas generating system of claim 1 further comprising

a housing having an outer wall;

and

wherein the baffle system comprises at least one baffle plate positioned within the housing, the at least one baffle plate defining a chamber having an entrance adapted for receiving therethrough a fluid from the first combustion chamber and a fluid from the second combustion chamber upon activation of the gas generating system, the at least one baffle plate having at least one opening therealong for enabling fluid communication between the chamber and an exterior of the chamber.

4. The gas generating system of claim 3 further comprising at least one opening in the housing wall to enable fluid communication between an interior of the housing and an exterior of the housing, and wherein the at least one opening in the housing wall is spaced apart from the at least one opening in the at least one baffle plate so as to provide a tortuous path for flow of a fluid between the chamber entrance and the at least one opening in the housing wall.

5. The gas generating system of claim 3 wherein the baffle system further comprises at least a second baffle plate and a third baffle plate, the second baffle plate being positioned interior of the housing wall and exterior of the at least one baffle plate so as to define a first fluid flow passage extending between the second baffle plate and the at least one baffle plate, the third baffle plate being positioned interior of the housing wall and exterior of the second baffle plate so as to define a second fluid flow passage extending between the second baffle plate and the third baffle plate, the second baffle plate having at least one opening therealong for enabling fluid communication between the first fluid flow passage and the second fluid flow passage, the third baffle plate having at least one opening therealong for enabling fluid communication between the second fluid flow passage and the housing wall.

6. The gas generating system of claim 5 further comprising at least one opening in the housing wall to enable fluid communication between an interior of the housing and an exterior of the housing, wherein the at least one opening in the housing wall is spaced apart from the at least one opening in the third baffle plate, the at least one opening in the third baffle plate is spaced apart from the at least one opening in the second baffle plate, the at least one opening in the second baffle plate is spaced apart from the at least one opening in the at least one baffle plate, so as to provide a tortuous path for flow of a fluid between the at least one baffle plate chamber entrance and the at least one opening in the housing wall.

7. The gas generating system of claim 5 wherein the baffle plates are generally cylindrical.

8. The gas generating system of claim 7 wherein the at least two of the baffle plates are positioned coaxially within the housing.

9. The gas generating system of claim 3 further comprising fluid flow passage positioned interior of the housing wall and extending along at least a portion of at least one of the first combustion chamber and the second combustion chamber, the fluid flow passage being in fluid communication with the baffle system, the housing wall having at least one opening formed therein along the fluid flow passage for enabling fluid communication between the fluid flow passage and an exterior of the housing.

10. The gas generating system of claim 1 wherein the first combustion chamber is positioned on an opposite side of the baffle system from the second combustion chamber.

11. The gas generating system of claim 1 further comprising a smokeless gas generant composition positioned in at least one of the first combustion chamber and the second combustion chamber.

12. A baffle system comprising:

a first end plate having at least one opening formed therein for enabling fluid communication with a first fluid source;

a second end plate having at least one opening formed therein for enabling fluid communication with a second fluid source;

a sequence of baffle elements extending between the first and second end plates, a first baffle element of the sequence of baffle elements defining a chamber for receiving therein a fluid through the at least one first end plate opening and for receiving therein a fluid through the at least one first end plate opening, each additional baffle element in the sequence of baffle elements being spaced outwardly apart from a preceding baffle element in the sequence of baffle elements, the first baffle element having an orifice configuration for enabling fluid communication between the chamber and an additional baffle element, each additional baffle element in the sequence of baffle elements having an orifice configuration for enabling fluid communication between a preceding baffle element and an exterior of the additional baffle element.

13. The baffle system of claim 12 wherein the first baffle element orifice configuration is spaced apart a first predetermined distance from the chamber entrance, and the orifice configuration in each additional baffle element is spaced apart an additional predetermined distance from the orifice configuration in the preceding baffle element, a sum of the first predetermined distance and the additional predetermined distances being approximately equal to an estimated total length per unit baffle element area of a flow path of a fluid necessary to cool a fluid flowing through the baffle system from a first temperature to a temperature within a predetermined temperature range.

14. A method for producing, in a gas generating system, a gas having a pressure within a predetermined pressure range and a temperature within a predetermined temperature range, the method comprising the steps of:

estimating a total length of a flow path of a gas along a given surface area of a predetermined baffle element material necessary to cool a gas to from a first temperature to a temperature within the predetermined temperature range; and

providing a baffle system positioned within the housing so as to enable fluid communication with the at least one combustion chamber upon activation of the gas generating system, the baffle system having a total internal gas flow path length per unit baffle element surface area substantially equal to the estimated length of gas flow path necessary to cool the gas to from a temperature in the at least one combustion chamber to a temperature within the predetermined temperature range, the baffle system having a baffle system orifice configuration within the baffle system along the internal flow path for the gas, the baffle system orifice configuration being adapted for reducing a pressure of a gas from a pressure in the at least one combustion chamber to a pressure within the predetermined pressure range.

15. The method of claim 14 wherein the step of providing a baffle system comprises the steps of:

providing a sequence of baffle elements formed from the baffle element material, a first baffle element of the sequence of baffle elements defining a chamber having an entrance adapted for receiving therethrough a gas from at least one combustion chamber upon activation of the gas generating system, each additional baffle element in the sequence of baffle elements being spaced outwardly apart from a preceding baffle element in the sequence of baffle elements;

providing an orifice configuration in the first baffle element for enabling fluid communication between the chamber and an additional baffle element, the first baffle element orifice configuration being spaced apart a first predetermined distance from the chamber entrance; and

providing an orifice configuration in each additional baffle element in the sequence of baffle elements for enabling fluid communication between a preceding baffle element and an exterior of the additional baffle element, the orifice configuration in each additional baffle element being spaced apart an additional predetermined distance from the orifice configuration in the preceding baffle element, a sum of the first predetermined distance and the additional predetermined distances being approximately equal to the estimated total length of a flow path of a gas necessary to cool the gas to a temperature within the predetermined temperature range.

19. The method of claim 14 wherein the step of providing a baffle system further comprises the step of varying the spacing between adjacent baffle plates such that the pressure of a gas flowing through an orifice configuration in the last baffle element in the sequence of baffle elements is at a pressure within the predetermined pressure range.

16. The method of claim 21 wherein the step of providing a baffle system further comprises the step of varying an orifice configuration in at least one of the baffle elements such that the pressure of a gas flowing through an orifice configuration in a last baffle element in the sequence of baffle elements is at a pressure within the predetermined pressure range.

17. The method of claim 16 wherein the step of varying an orifice configuration in at least one of the baffle elements comprises varying the sizes of the orifices in at least one of the baffle elements.

18. The method of claim 16 wherein the step of varying an orifice configuration in at least one of the baffle elements comprises varying the number of orifices in at least one of the baffle elements.

20. A vehicle occupant protection system comprising:

an airbag system including an airbag and a gas generating system coupled to the airbag so as to enable fluid communication with the airbag upon activation of the airbag system, the gas generating system having

a first combustion chamber;

a second combustion chamber; and

a baffle system positioned adjacent both the first and second combustion chambers

so as to enable fluid communication with the first combustion chamber and the second combustion chamber upon activation of the gas generating system.