Auto-Ignition Gas Generant Composition for Airbag Inflators
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Solution Overview
Problem
Current gas generating compositions in automotive airbag inflators do not auto-ignite at temperatures below 250 degrees Celsius, making them unsuitable for safe deployment in fires, and they are also hygroscopic, affecting ignitability and stability, while manufacturing processes are complex and costly.
Innovation Solution
A gas generant system comprising a primary fuel, a salt of tetrazole, a metallic oxidizer, and a catalyst, such as 5-aminotetrazole, dinitrobenzoic acid, potassium nitrate, and molybdenum trioxide, which auto-ignites at temperatures below 215 C, enhancing stability and reducing hygroscopicity, thus simplifying the composition into a single gas generating and auto-ignition composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gas generating compositions are used to produce large amounts of gas, then gas generation capability is improved, but auto-ignition temperature increases to above 250 degrees Celsius
Solution Approach 1:
The patent combines the auto-ignition function and gas generation function into a single integrated composition. The gas generating composition is formulated to simultaneously exhibit both auto-ignition capability at low temperatures and high gas generation capacity, eliminating the need for separate auto-ignition and gas generating compositions.
Solution Approach 2:
The patent modifies the chemical composition parameters by incorporating specific fuels (tetrazole derivatives, nitro compounds), oxidizers (metal nitrates, metal carbonates), and catalysts (transition metal compounds). These parameter changes enable the composition to auto-ignite at temperatures below 250°C while maintaining high gas generation capability.
2Reliability
If separate auto-ignition and gas generating compositions are used, then auto-ignition function is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The gas generating composition is designed to perform multiple functions: it serves as both the auto-ignition composition and the main gas generating composition. This multi-functional design simplifies the overall system structure, reducing the number of components and manufacturing steps while ensuring reliable auto-ignition function.
3Quantity of substance
If traditional gas generating compositions are used, then gas production is sufficient, but hygroscopicity adversely affects ignitability and stability
Solution Approach 1:
The patent selects specific chemical compounds with controlled hygroscopic properties. The fuel components (tetrazole derivatives, nitro compounds), oxidizers (metal nitrates, metal carbonates), and catalysts are chosen to minimize moisture absorption while maintaining gas generation performance and thermal stability.
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 system achieves improved effluent quality, booster performance, and auto-ignition at lower temperatures with enhanced stability, reducing the need for separate auto-ignition and gas generating compositions, leading to lighter, more efficient inflators with reduced manufacturing costs and improved safety.
Implementation Method 1
gas generating compositions typically produce relatively larger amounts of gas as compared to auto-ignition compositions. The gas generating composition must not only burn with sustained combustion
Implementation Method 2
A composition in accordance with the present invention includes a primary fuel, a salt of tetrazole, a metallic oxidizer, and a catalyst
Implementation Method 3
An oxidizer is selected from metal oxidizers including alkali metal oxidizers such as potassium nitrate, sodium nitrate
Implementation Method 4
The gas generating composition must not only burn with sustained combustion
Data Source
AI summary
The present invention generally relates to auto-ignition/booster compositions for inflators of occupant restraint systems, for example. An auto-ignition/booster and/or gas generant composition in accordance with the present invention includes an aromatic acid selected from tetrazoles, carboxylic acid/benzene-based fuels, nitrotriazoles, aminonitrotriazoles, aminotriazoles, bistetrazolylamines, bitetrazoles, and mixtures thereof; an alkali metal nitrate selected from potassium nitrate and sodium nitrate, and mixtures thereof; a basic constituent; and a catalytic non-oxidizing molybdenum-containing additive. A gas generator and a gas generating system including compositions of the present invention are also contemplated.