Gas Generator Initiator With Hermetic Pyrotechnic Separation

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Solution Overview

Problem

Existing initiators for vehicle safety devices face performance shifts due to chemical incompatibility between primary and secondary pyrotechnic materials.

Innovation Solution

An initiator design that hermetically separates primary and secondary pyrotechnic materials using a separator member, ensuring mechanical separation and eliminating chemical incompatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If primary and secondary pyrotechnic materials are stored together in the initiator, then the device complexity is reduced, but chemical incompatibility causes performance shifts and reliability deterioration

Engineering Contradiction:
Improveinitiator performance consistencyVSAvoidinitiator structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The initiator is segmented into distinct compartments using a separator member that divides the interior space. The primary pyrotechnic material and secondary pyrotechnic material are stored in separate compartments, preventing direct contact while maintaining individual functionality. This segmentation resolves the chemical incompatibility issue without requiring complete structural redesign.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A separator member acts as an intermediary barrier between the primary and secondary pyrotechnic materials. This intermediate structure prevents harmful chemical interactions while allowing the initiator to function as intended. The separator member is specifically designed to withstand the operational conditions while maintaining hermetic separation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a separator member is added to hermetically separate the pyrotechnic materials, then chemical incompatibility is eliminated, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveperformance consistencyVSAvoidinitiator assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The separator member is designed as a modular component that divides the initiator interior into distinct compartments. This segmentation approach allows for standardized manufacturing of the separator and facilitates assembly by enabling pre-packaging of pyrotechnic materials in separate compartments before final assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separator member utilizes a thin-walled cup structure that provides hermetic separation while minimizing material usage and structural complexity. This thin-film approach maintains effectiveness in preventing chemical interactions while reducing manufacturing difficulty compared to thick-walled rigid separators.

Inventive Principle:
Principle #30Flexible shells and thin films

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 hermetic separation enhances the reliability and performance consistency of the initiator by preventing performance shifts caused by chemical interactions between the primary and secondary pyrotechnic materials.

Implementation Method 1

A separator member hermetically separates the primary pyrotechnic material from the secondary pyrotechnic material

Methodology Applied
Scientific EffectHermetic separation: Physical Containment

Implementation Method 2

The primary pyrotechnic material is ignited by an electrical signal

Methodology Applied
Scientific EffectElectrical ignition: Electric Spark

Implementation Method 3

Heat from combustion of the secondary pyrotechnic material ignites gas generant material

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

Heat from combustion of the secondary pyrotechnic material ignites gas generant material of the inflator device

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4122778B1Initiator for a gas generator of vehicle safety device
Publication Date: 2025.07.09 AUTOLIV ASP INC
  • EP4122778B1 patent drawingFigure 1
  • EP4122778B1 patent drawingFigure 2
  • EP4122778B1 patent drawingFigure 3

AI summary

An initiator (10) for a gas generator of a vehicle safety device includes a cup (12) defining an interior, a primary pyrotechnic material (14) disposed in the interior of the cup (12), and a secondary pyrotechnic material (16) disposed in the interior of the cup (12). A separator member (28) hermetically separates the primary pyrotechnic material (14) from the secondary pyrotechnic material (16).