Gas Generator Diffuser with Cylindrical Filter for Residue Trapping

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Solution Overview

Problem

Existing gas generators for airbag deployment systems face issues with high-temperature combustion residues damaging the airbag due to excessive discharge of combustion residues from the gas generator.

Innovation Solution

A gas generator design incorporating a cylindrical filter with an annular inclined surface and a trapping space within the diffuser portion to effectively capture and retain combustion residues, reducing their discharge through the gas discharge port.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gas generating agent is combusted to generate combustion gas for airbag deployment, then the airbag can be deployed effectively, but high-temperature combustion residues are discharged and may damage the airbag

Engineering Contradiction:

Improveairbag deployment effectivenessVSAvoidcombustion residue damage to airbag

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A cup-shaped partition wall is introduced as an intermediary component between the combustion chamber and the gas discharge port. This partition wall creates a trapping space that captures combustion residues before they can exit through the discharge port, while still allowing combustion gas to pass through to deploy the airbag effectively.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The diffuser portion is segmented into multiple functional zones: a trapping space for capturing combustion residues, a gas discharge port for releasing combustion gas, and a cylindrical filter for further residue filtration. This segmentation allows simultaneous achievement of effective airbag deployment and combustion residue containment.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If the diffuser portion structure is simplified, then manufacturing is easier, but combustion residues cannot be effectively trapped

Engineering Contradiction:

Improvediffuser portion manufacturing simplicityVSAvoidcombustion residue trapping effectiveness

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The cup-shaped partition wall is designed to perform multiple functions simultaneously: it creates the trapping space for combustion residues, serves as a structural component of the diffuser portion, and guides the flow of combustion gas. This merging of functions achieves effective residue trapping without significantly complicating the manufacturing process.

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If a complex filtering system is used to trap combustion residues, then residue discharge is reduced, but device complexity increases

Engineering Contradiction:

Improvecombustion residue discharge amountVSAvoidgas generator structure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of implementing a complex filtering system throughout the entire gas generator, the invention applies a localized cup-shaped partition wall with specific geometric features (inclined inner surface, trapping space) at the critical location where combustion residues accumulate. This localized approach effectively traps residues without requiring complex filtering systems throughout the entire device.

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

Significantly reduces the amount of combustion residues discharged from the gas generator, enhancing the safety and integrity of the airbag deployment system by trapping residues within the diffuser portion's trapping space.

Implementation Method 1

The diffuser portion includes therein a cylindrical filter covering from an inside of the diffuser portion the gas discharge port

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Implementation Method 2

a trapping space for trapping a combustion residue contained in the combustion gas is provided so as to be surrounded by the bottom surface of the diffuser portion and the annular inclined surface

Methodology Applied

Scientific EffectGravitational settling: Gravitation

Data Source

PatentUS11091119B2Gas generator

Publication Date: 2021.08.17 DAICEL CORP

AI summary

A gas generator, including an igniter provided in a cylindrical housing, a combustion chamber filled with a gas generating agent, and being provided within the cylindrical housing; and a diffuser portion including a gas discharge port being coupled to the cylindrical housing, the diffuser portion including a bottom surface, a peripheral wall having the gas discharge port, and an opening, the diffuser portion including therein a cylindrical filter covering, from an inside of the diffuser portion, the gas discharge port, the cylindrical filter being disposed such that a first annular end face thereof abuts against the bottom surface of the diffuser portion and a second annular end face thereof is located to be on a side of the opening of the diffuser portion, the cylindrical filter having an annular inclined surface extending in an obliquely inward direction from the first annular end face, and a trapping space for trapping a combustion residue contained in the combustion gas being provided so as to be surrounded by the bottom surface of the diffuser portion and the annular inclined surface.