Hybrid gas generator, method for operating a hybrid gas generator, airbag module and vehicle safety system

Patent metadata

Field	Value
Publication number	US-11766988-B2
Application number	US-201716477540-A
Country	US
Kind code	B2
Filing date	Nov 20, 2017
Priority date	Jan 18, 2017
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

The invention relates to a hybrid gas generator ( 10 ) which comprises a compressed gas chamber ( 20 ) and an igniting unit ( 30 ), wherein the compressed gas chamber ( 20 ) is closed by a first igniter-side bursting membrane ( 21 ) and a second bursting membrane ( 22 ). According to the invention, a first, rapidly burning-off pyrotechnic agent ( 51 ) and a second pyrotechnic agent ( 52 ) burning off slowly in comparison to the first pyrotechnic agent ( 51 ) are located in the hybrid gas generator ( 10 ), wherein the second bursting membrane ( 22 ) is openable by positive pressure which can be generated in the compressed gas chamber ( 20 ) and the first pyrotechnic agent ( 51 ) is separated from the second pyrotechnic agent ( 52 ) in such a manner that the positive pressure in the compressed gas chamber ( 20 ) for opening the second bursting membrane ( 22 ) can be generated by the first pyrotechnic agent ( 51 ).

First claim

The invention claimed is:

1. A hybrid gas generator comprising:
a compressed gas chamber closed off by a first bursting membrane and a second bursting membrane;
an igniting unit comprising an igniter;
a first pyrotechnic agent configured to be ignited by the igniter; and
a second pyrotechnic agent configured to be ignited by burning off of the first pyrotechnic agent, the second pyrotechnic agent being configured to burn off slowly as compared to the first pyrotechnic agent;
wherein the second pyrotechnic agent is disposed in the compressed gas chamber and the first pyrotechnic agent is contained within a holder of the igniting unit outside the compressed gas chamber, the first bursting membrane being secured to the holder and separating the first pyrotechnic agent in the holder from the second pyrotechnic agent in the compressed gas chamber;
wherein the separation of the first and second pyrotechnic agents is configured so that the second bursting membrane opens due to a pressure rise in the compressed gas chamber resulting from the burning off of the first pyrotechnic agent, wherein the second pyrotechnic agent is disposed in a combustion chamber within the compressed gas chamber, the combustion chamber being axially separated from a pyrotechnic chamber in the holder where the first pyrotechnic agent is contained, and wherein the combustion chamber is spaced apart from the pyrotechnic chamber by a resilient element.

2. The hybrid gas generator recited in claim 1 , wherein the holder is configured to support the first bursting membrane, the holder defining a chamber within the compressed gas chamber that contains the first pyrotechnic agent, wherein the holder and the first bursting membrane isolate the first pyrotechnic agent from the second pyrotechnic agent prior to activation of the inflator.

3. The hybrid gas generator recited in claim 2 , wherein the igniter is configured to ignite the first pyrotechnic agent and rupture the first bursting membrane, which opens the holder and releases burn-off gases of the first pyrotechnic agent into the compressed gas chamber, which creates the pressure rise in the compressed gas chamber that opens the second bursting membrane.

4. The hybrid gas generator recited in claim 1 , wherein the gas generator is configured so that the pressure rise in the compressed gas chamber opens the second bursting membrane without influence from a shockwave and with the hybrid gas generator being free from projectiles for puncturing the second bursting membrane.

5. The hybrid gas generator according to claim 1 , wherein the burning off of the first pyrotechnic agent forms positive pressure in the compressed gas chamber that directly opens the second bursting membrane.

6. An airbag module configured for installation in a vehicle, comprising the hybrid gas generator according to claim 1 and an airbag inflatable by the hybrid gas generator.

7. A vehicle safety system for protecting a person, comprising a hybrid gas generator, an airbag inflatable by the gas generator as part of an airbag module, and an electronic control unit configured to activate the hybrid gas generator when a release situation is given, wherein the hybrid gas generator is configured according to claim 1 .

8. A method for operating the hybrid gas generator according to claim 1 , comprising steps of:
a) activating the igniting unit of the hybrid gas generator;
b) igniting the first pyrotechnic agent, which ruptures the first bursting membrane and releases burn-off gases into the combustion chamber;
c) building up, via the burn-off gases released into the compressed gas chamber, positive pressure in the compressed gas chamber;
d) igniting the second pyrotechnic agent and partially generating propelling gas;
e) opening the second bursting element due to the built-up positive pressure in the compressed gas chamber;
f) generating further propelling gas by the second pyrotechnic agent; and
g) discharging the further propelling gas through the opened second bursting element.

9. The method for operating the hybrid gas generator according to claim 8 , wherein the first pyrotechnic agent acts as ignition booster for the second pyrotechnic agent and as positive pressure generator, wherein the positive pressure required for opening the second bursting element is generated prior to reaching a maximum gas generation rate of the second pyrotechnic agent.

10. The method according to claim 8 , wherein the maximum gas generation rate of the second pyrotechnic agent is reached subsequent to the method step e), and/or wherein bursting of the first bursting element is carried out subsequent to the step a) or the step b).

Assignees

• Trw Airbag Sys Gmbh

Inventors

• Jung Christian
• Bierwirth Sebastian
• Ebner Johannes
• Neumayer Hans-Peter
• Oberstarr Martin
• Hillmann Daniel
• Isenmann Uta
• Last Detlef

Classifications

• B60R21/272 Primary

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

• B60R21/2644

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

• B60R21/36

  using airbags · CPC title

• B60R2021/2648

  comprising a plurality of combustion chambers or sub-chambers · CPC title

• B60R21/274

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