Airbag Gas Generator Segmented Chamber Design

Solution Overview

Problem

Existing gas generators for airbags have complex internal architectures leading to high manufacturing costs and issues with residual pressure and lid opening, which can result in insufficient gas flow and reduced inflation efficiency.

Innovation Solution

A gas generator with a simple and reliable opening mechanism, featuring two chambers with an adjustable gas passage that allows for independent control of gas flow, using a single discharge orifice and separate actuators for each chamber, enabling flexible design and robust storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If duplicate mechanisms are used to open each pressurized gas reserve discharge orifice, then the gas generator can adapt the quantity of gas diffused into the airbag, but the manufacturing cost increases due to numerous components

Engineering Contradiction:

Improveadaptability of gas flow quantityVSAvoidcomplexity of internal architecture

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The first gas reserve is divided into two chambers (first chamber and second chamber) separated by a partition. This segmentation allows independent control of gas release from each chamber, enabling adaptation of gas flow quantity without requiring duplicate discharge orifice mechanisms. The partition contains two gas passages that can be selectively opened to regulate the amount of gas entering the diffusion chamber.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If duplicate mechanisms are used to open each pressurized gas reserve discharge orifice, then the gas generator can adapt the quantity of gas diffused into the airbag, but the manufacturing cost increases due to numerous components

Engineering Contradiction:

Improveadaptability of gas flow quantityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The first gas reserve is divided into two chambers (first chamber and second chamber) separated by a partition. This segmentation allows independent control of gas release from each chamber, enabling adaptation of gas flow quantity without requiring duplicate discharge orifice mechanisms. The partition contains two gas passages that can be selectively opened to regulate the amount of gas entering the diffusion chamber.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If the opening mechanism supports a thin lid during storage and removes support to open, then the mechanism is simple, but the residual pressure reduction may prevent sufficient pressing force to open the lid

Engineering Contradiction:

Improvesimplicity of opening mechanismVSAvoidreliability of lid opening

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The lid is designed as a movable component that transitions between a closed position (supported during storage) and an open position. The igniter creates a pressure wave that dynamically overcomes the residual pressure, pushing the lid from the closed to open position. This dynamic approach ensures reliable opening even when residual pressure is present.

Inventive Principle:

Principle #15Dynamics

4Speed

If the first chamber is placed in direct communication with the discharge orifice, then rapid gas emptying is achieved, but the second chamber cannot control gas flow rate

Engineering Contradiction:

Improvespeed of gas emptyingVSAvoidcontrol of gas flow rate

Core Design Contradiction:

SpeedVSAdaptability or versatility

Solution Approach 1:

The partition between the first and second chambers contains two gas passages with adjustable opening. The second gas passage can be dynamically opened or closed to control the flow rate from the second chamber to the first chamber. This allows regulation of gas transfer speed while maintaining direct communication between the first chamber and the discharge orifice for rapid ejection.

Inventive Principle:

Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides adaptable gas flow rates and maintains combustion equilibrium between hydrogen and oxygen, ensuring effective airbag inflation by restoring concentration ratios and compensating for volume loss during combustion, thus enhancing the inflation power and reliability of the airbag deployment.

Implementation Method 1

The first igniter, during its operation, creates a pressure wave which opens the first discharge orifice and ruptures the lid

Methodology Applied

Scientific EffectPressure wave: Shock Wave

Implementation Method 2

The second igniter, during its operation, creates a pressure wave which opens the second gas passage

Methodology Applied

Scientific EffectPressure wave: Shock Wave

Implementation Method 3

maintains combustion equilibrium between hydrogen and oxygen, ensuring effective airbag inflation by restoring concentration ratios

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentEP2740635B1Gas generator

Publication Date: 2017.04.26 AUTOLIV DEV AB

Figure 1~2

AI summary

The generator has a gas reservoir (100) partitioned into two chambers (110, 120), where one of the chambers is in communication with a discharge opening (130) while the other chamber is separated from the former chamber by a wall (121). The wall includes a gas passage (111) with an opened passage surface, and a closed gas passage (112). A blocking mechanism (400) blocks and opens the closed gas passage independent of an actuator (310) i.e. pyrotechnical electro lighter.