Gas Generator Guide Member Flow Control

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Solution Overview

Problem

Existing gas generators for airbag systems face challenges in achieving uniform ignition and combustion of the gas generating agent, leading to incomplete burning and reduced performance due to inefficient flow of combustion products from the ignition chamber to the combustion chamber.

Innovation Solution

The design incorporates a guide member within the gas generator to direct combustion products from the ignition chamber towards the bottom plate of the combustion chamber, ensuring they flow radially outward and ignite the gas generating agent more effectively, with the outlet for combustion products positioned closer to the bottom plate than the gas discharge port.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If combustion products are discharged directly from the ignition chamber without directional guidance, then the structure is simpler, but the ignition and combustion performance of the gas generating agent is insufficient

Engineering Contradiction:
Improveignition and combustion performanceVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A guide member is introduced as an intermediary component between the ignition chamber and combustion chamber. This guide member directs the flow of combustion products from the ignition chamber toward the bottom plate and radially outward, ensuring uniform distribution over the gas generating agent. The guide member acts as a mediator that transforms the direct discharge into a controlled, directional flow pattern, improving ignition reliability without requiring complex multi-component systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The guide member utilizes the vertical dimension by positioning its outlet closer to the bottom plate than to the gas discharge port. This vertical arrangement allows combustion products to flow downward and then radially outward, creating a three-dimensional flow pattern that enhances contact with the gas generating agent. The vertical positioning of the outlet enables better distribution across the combustion chamber floor

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the outlet for combustion products is positioned at the top near the gas discharge port, then the gas can be discharged quickly, but the combustion products do not effectively ignite the entire gas generating agent

Engineering Contradiction:
Improvecombustion completenessVSAvoidignition time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The guide member is designed to preliminarily direct combustion products toward the bottom plate before they reach the gas generating agent. By positioning the outlet near the bottom and using the guide member's geometry to shape the flow, combustion products are pre-positioned to maximize contact with the gas generating agent surface, ensuring complete ignition before the main gas discharge occurs

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The guide member creates localized high-temperature zones by concentrating combustion products at specific areas near the bottom plate where the gas generating agent is most needed. The outlet positioning and guide member geometry ensure that combustion products are delivered precisely where they can most effectively initiate and propagate combustion across the entire agent

Inventive Principle:
Principle #3Local quality

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

This configuration enhances the ignition and combustion performance of the entire gas generating agent, ensuring complete burning and improved efficiency in generating combustion gas for airbag deployment.

Implementation Method 1

a guide member provided at least in an outer side or an inner side of the circumferential wall, so that combustion products generated inside the ignition chamber are discharged from the nozzles and guided towards the bottom plate of the second shell

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

an ignition device disposed inside the ignition chamber; and a solid gas generating agent charged in the combustion chamber to generate combustion gas

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP2841312B1Gas generator
Publication Date: 2017.07.05 DAICEL CORP
  • EP2841312B1 patent drawingFigure 1~2
  • EP2841312B1 patent drawingFigure 3~4(c)
  • EP2841312B1 patent drawingFigure 5(a)~5(b)

AI summary

The present invention provides a gas generator including a housing, an inner cylindrical member defining an ignition chamber therein and a combustion chamber outside, an ignition device disposed inside the ignition chamber, a solid gas generating agent charged in the combustion chamber, the inner cylindrical member including, a plurality of nozzles provided in a circumferential wall to communicate the ignition chamber with the combustion chamber, a guide member provided at least in the outer side or the inner side of the circumferential wall, so that combustion products from the ignition chamber is discharged from the nozzles and guided towards a bottom plate of the housing, the combustion chamber defined by the circumferential wall of the inner cylindrical member and the circumferential wall portion of the housing, an outlet from the inner cylindrical member being formed closer to the bottom plate than to the gas discharge port.