Self-Initiating Composition for Gas Generators
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Solution Overview
Problem
Current self-initiating compositions for gas generators in automobile safety applications face challenges such as instability at high temperatures, toxicity, and excessive self-initiation temperatures, leading to potential explosions and unsatisfactory performance in environmental tests.
Innovation Solution
A self-initiating composition comprising 20-80% alkali metal chlorate, 5-50% energetic organic compounds, and optional metal or metalloid reducing agents and transition metal oxides, optimized to achieve a self-initiation temperature between 130°C and 180°C, ensuring stability and controlled ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a self-initiating composition with low self-ignition temperature is used, then the combustion can be triggered at lower temperatures, but the composition becomes unstable at high temperatures and may decompose excessively
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing specific metal oxides (manganese oxide, cobalt oxide, copper oxide) and metal powders (zirconium, titanium, aluminum) into the self-initiating composition. These additives change the thermal decomposition characteristics, enabling the composition to remain stable at high temperatures while still achieving ignition at controlled temperatures between 130°C and 180°C.
Solution Approach 2:
The patent creates a composite self-initiating composition combining multiple components: alkali metal chlorates (potassium chlorate, sodium chlorate), energetic organic compounds (guanidinium nitrate, 5-aminotetrazole, azodicarbonamide), and catalytic metal oxides/metals. This composite structure leverages the complementary properties of each component to achieve both high-temperature stability and controlled low-temperature ignition.
2Reliability
If the self-initiation temperature is reduced below 180°C, then premature initiation is prevented, but the composition may become too sensitive and initiate too quickly
Solution Approach 1:
The patent introduces metal oxides (manganese oxide, cobalt oxide, copper oxide) and metal powders as intermediary substances that mediate the thermal decomposition process. These intermediaries act as catalysts that lower the activation energy barrier for decomposition, enabling controlled ignition at temperatures between 130°C and 180°C while preventing both premature initiation and excessively rapid combustion.
3Weight of moving object
If aluminum is used for the gas generator casing to reduce weight, then fuel consumption improves, but the casing loses mechanical integrity at high temperatures
Solution Approach 1:
The patent converts the harmful effect of high temperatures into a beneficial control mechanism. By designing the self-initiating composition to ignite at controlled temperatures between 130°C and 180°C, the system utilizes the thermal environment to trigger ignition precisely when needed, before the aluminum casing loses its mechanical integrity, thereby transforming a potential hazard into a safety feature.
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 composition provides stable operation at elevated temperatures, preventing unintended ignition during environmental tests and ensuring reliable initiation of gas-generating compositions, thus enhancing safety and performance in automotive applications.
Implementation Method 1
The self-initiating composition is therefore to decompose exothermically, so that the evolution of heat triggers the combustion of the gas-generating composition
Implementation Method 2
5 to 50% by mass of at least one energetic organic compound
Implementation Method 3
These are generally mixtures of oxidants and reducers, and in particular mixtures of oxidants and mineral reducers
Implementation Method 4
0 to 50% by mass of at least one transition metal oxide
Data Source
AI summary
The invention relates to a self-initiating composition for a gas generator comprising a main formulation which contains at least 20-80 mass % one type of alkali metal chlorate and 5-50 mass % energetic organic compound, preferably guanidine nitrate, and is characterised in that said main formulation also contains (a) at least 0-60 mass % one type of metal or metalloid selected from boron, manganese, cobalt and copper, (b) at least 0-60 mass % one type of metal or metal hydride selected from zirconium, titanium, TiH2, ZrH2, aluminium, silicium and iron, (c) at least 0-50 mass % one type of transition metal oxide, wherein the mass percentages are expressed in relation to the main formulation mass and the mass percentages of the components (a) and (c) can not simultaneously be equal to zeros. Said invention relates, in particular to self-initiating compositions whose self-initiation temperature ranges from 150 to 180 °C and which are stable during 408 hours at a temperature of 107 °C. The inventive compositions can be used for an electrical initiator and for a gas generator.