Hybrid gas generator for filling a gas bag

• US 5,586,783 A
• Filed: 02/23/1995
• Issued: 12/24/1996
• Est. Priority Date: 02/24/1994
• Status: Expired due to Fees

• Current Assignee: TEMIC Bayern-Chemie Airbag GmbH
• Original Assignee: TEMIC Bayern-Chemie Airbag GmbH
• Inventors: Adam, Paul, Renn, Peter, Tillmann, deceased, Heinz, Reif, Joachim, Dolling, Uwe, Werner, Michael
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): English, Peter C.
• Application Number:
  US08/393,361
• Time in Patent Office: 670 Days
• Field of Search: 280/737, 280/736, 280/740, 280/741, 222/3, 137/68.2, 137/68.12, 137/68.13, 137/68.19, 137/68.28, 137/74, 137/72
• US Class Current: 280/737
• 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 5/06 by reaction of two or more solids
• CPC Class Codes: Y10T 137/1647 Explosive actuation
• CPC Class Codes: Y10T 137/1812 In fluid flow path

Abstract

A hybrid gas generator includes a pyrotechnic gas generator joined to a high-pressure vessel which is sealed with a sealing disk composed of a substance which chemically reacts with propellant gas produced in use so that the sealing disk is opened with an advantageously reduced acoustic pressure. The propellant gas is chemically reactive and is produced from a propellant composition which is present in a surplus amount and which is composed of a propellant which is oxidizable and at least one oxidant for oxidizing the propellant. The propellant gas attacks the sealing disk chemically and thermally, and continuously burns through it to release the gas from the high-pressure vessel into a mixing chamber in the pyrotechnic gas generator.

Claims

1. A hybrid gas generator, comprising:

a. a pyrotechnic gas generator which is comprised of;

a enveloping housing which is provided with a plurality of outlet openings;

an igniter which is positioned within the enveloping housing;

a mixing chamber which is provided within the enveloping housing and which is in communication with the plurality of outlet openings; and

a combustion chamber which is provided within the enveloping housing in communication with the igniter, which has defined therein a blow-out opening in communication with the mixing chamber, and which contains a propellant composition comprised of a propellant which is oxidizable and an amount in excess of a stoichiometric amount of at least one oxidant for oxidizing the propellant in use to generate a propellant gas which is chemically reactive by igniting the propellant composition with the igniter; and

b. a high-pressure vessel which is comprised of;

a housing which contains gas under pressure;

an outflow opening which is defined in the high-pressure vessel and at which the high-pressure vessel is joined to the pyrotechnic gas generator; and

a sealing disk which is sealingly joined to the housing and positioned between the outflow opening of the high-pressure vessel and the mixing chamber of the pyrotechnic gas generator opposite the blow-out opening of the combustion chamber so that the propellant gas produced in the combustion chamber in use impinges against the sealing disk, and which is comprised of a substance which chemically reacts with the propellant gas so that the propellant gas attacks the sealing disk chemically and thermally, and continuously burns through the sealing disk as in a welding process in use whereby the sealing disk opens with a substantially reduced acoustic pressure and without a bang, the gas from the high-pressure vessel flows into the mixing chamber, mixes with the propellant gas to provide a gas mixture, and the gas mixture flows through the plurality of outlet openings provided in the enveloping housing of the pyrotechnic gas generator into a gas bag.

2. The hybrid gas generator in accordance with claim 1, wherein the propellant composition comprises an amount of the at least one oxidant in excess of that required to oxidize the propellant.

3. The hybrid gas generator in accordance with claim 2, wherein the sealing disk is comprised of a substance which is easily combusted by the propellant gas.

4. The hybrid gas generator in accordance with claim 3, wherein the substance which is easily combusted by the propellant gas is selected from the group consisting of a steel foil and a light metal sheet.

5. The hybrid gas generator in accordance with claim 4, wherein the sealing disk has a structure such that the burning of the sealing disk generates a mass flow of the gas from the high-pressure vessel over a specific period of time.

6. The hybrid gas generator in accordance with claim 5, wherein the sealing disk is sealingly joined to the housing of the high-pressure vessel by a weld.

7. The hybrid gas generator in accordance with claim 6, wherein the sealing disk is sealingly joined to the housing of the high-pressure vessel in a gas tight manner, and wherein the weld is one of a laser weld or an electron-beam weld.

8. The hybrid gas generator in accordance with claim 7, further comprising a component which is positioned between the mixing chamber and the plurality of outlet openings which cleans and tempers the mixture of gases, which dampens sound produced, and which acts as a catalyst for reducing amounts of undesired gases.

9. The hybrid gas generator in accordance with claim 8, wherein the component is comprised of a material selected from the group consisting of a metal and a ceramic.

10. The hybrid gas generator in accordance with claim 9, wherein the component has a form selected from the group consisting of a grating, a mesh, and a felt.

11. The hybrid gas generator in accordance with claim 1, further comprising a component which is positioned between the mixing chamber and the plurality of outlet openings which cleans and tempers the mixture of gases, which dampens sound produced, and which acts as a catalyst for reducing amounts of undesired gases.

12. The hybrid gas generator in accordance with claim 11, wherein the component is comprised of a material selected from the group consisting of a metal and a ceramic.

13. The hybrid gas generator in accordance with claim 12, wherein the component has a form selected from the group consisting of a grating, a mesh, and a felt.

14. The hybrid gas generator in accordance with claim 1, further comprising a dam provided at the blow-out opening of the combustion chamber to keep the combustion chamber closed prior to use during which the production of hot propellant gas causes the dam to burst open and allows the propellant gas to escape from the combustion chamber through the blow-out opening into the mixing chamber.

15. The hybrid gas generator in accordance with claim 1, further comprising a pressure measuring device provided in the high-pressure vessel remote from the outflow opening.

16. In a hybrid gas generator comprised of:

a pyrotechnic gas generator which is comprised of a enveloping housing which is provided with a plurality of outlet openings;

an igniter which is positioned within the enveloping housing;

a mixing chamber which is defined within the enveloping housing and which is in communication with the plurality of outlet openings; and

a combustion chamber which is provided within the enveloping housing in communication with the igniter, which has defined therein a blow-out opening in communication with the mixing chamber, and which contains a propellant composition comprised of a propellant which is oxidizable and at least one oxidant for oxidizing the propellant in use to generate a propellant gas by igniting the propellant composition with the igniter; and

a high-pressure vessel which is comprised of a housing which contains gas under pressure;

an outflow opening which is defined in the high-pressure vessel and at which the high-pressure vessel is joined to the pyrotechnic gas generator; and

a sealing disk which is sealingly joined to the housing and positioned between the outflow opening of the high-pressure vessel and the mixing chamber of the pyrotechnic gas generator opposite the blow-out opening of the combustion chamber so that the propellant gas produced in the combustion chamber in use impinges against the sealing disk in use whereby the gas from the high-pressure vessel flows into the mixing chamber, mixes with the propellant gas to provide a gas mixture, and the gas mixture flows through the plurality of outlet openings provided in the enveloping housing of the pyrotechnic gas generator into a gas bag, the improvement in which;

the propellant composition contains an amount in excess of a stoichiometric amount of the at least one oxidant for oxidizing the propellant in use and generates in use propellant gas which is chemically reactive; and

the sealing disk is comprised of a substance which chemically reacts with the propellant gas so that the propellant gas attacks the sealing disk chemically and thermally, and continuously burns through the sealing disk as in a welding process in use whereby the sealing disk is opened with a substantially reduced acoustic pressure and without a bang.