Gas-Generating Composition for Temperature-Stable Airbag Combustion
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Solution Overview
Problem
Existing gas generators for airbag apparatuses face challenges in maintaining stable output due to ambient temperature fluctuations, with previous solutions either increasing the generator's size or failing to actively stabilize the combustion performance.
Innovation Solution
A gas generating composition comprising 15% to 25% melamine cyanurate and 75% to 85% nitroguanidine as fuel, combined with 60% to 70% basic copper nitrate and 30% to 40% basic copper carbonate as oxidizing agents, which maintains a combustion temperature within 10 K of copper's melting point and ensures a temperature difference of less than 125 K across the ambient temperature range of -40°C to 85°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gas generator uses conventional gas generating compositions, then the output fluctuates with ambient temperature changes, but if the generator size is increased to stabilize output, then the device complexity and volume increase
Solution Approach 1:
The patent changes the chemical composition parameters of the gas generating agent by using specific ratios of fuel (melamine cyanurate and nitroguanidine) and oxidizing agent (basic copper nitrate and basic copper carbonate), and by controlling the combustion temperature to match the melting point of copper, thereby stabilizing the gas generation output across different ambient temperatures without increasing generator volume
Solution Approach 2:
The patent employs a composite gas generating composition consisting of multiple components: fuel (melamine cyanurate and nitroguanidine), oxidizing agent (basic copper nitrate and basic copper carbonate), and binder (carboxymethyl cellulose sodium salt). This composite formulation enables stable combustion characteristics and consistent gas output across varying ambient temperatures
2Productivity
If the combustion temperature is increased to improve gas generation speed, then the temperature control precision decreases and output stability worsens
Solution Approach 1:
The patent utilizes the phase transition of copper from solid to liquid at its melting point (1358 K) as a natural temperature regulator. By designing the combustion temperature to coincide with copper's melting point, the system automatically maintains stable temperature during combustion, ensuring both rapid gas generation and precise temperature control
Solution Approach 2:
The copper component in the composition serves a dual function: as a structural/material component and as a self-regulating temperature control mechanism. The combustion temperature naturally stabilizes at copper's melting point, providing self-regulation without external control systems
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 composition ensures stable combustion performance and output across varying ambient temperatures, preventing temperature rises during combustion and maintaining consistent ignition and pressure, thus addressing the instability issues in previous gas generator technologies.
Implementation Method 1
when ignited for combustion at an ambient temperature within a range of -40°C to 85°C
Implementation Method 2
the combustion temperature is the melting point of a substance included in the combustion residue
Implementation Method 3
the combustion temperature is the melting point of a substance included in the combustion residue
Implementation Method 4
the combustion temperature is the melting point of a substance included in the combustion residue
Data Source
Figure 1
AI summary
Provided is a gas generating composition which can maintain stable combustion performance even under variation of ambient temperature. The gas generating composition includes (a) a fuel and (b) an oxidizing agent and meets the following requirements (I) and (II): (I) a combustion temperature at a time of ignition and combustion at any ambient temperature within a range of -40°C to 85°C is a melting point of a substance included in a combustion residue; and (II) a difference between combustion temperatures at the time of ignition and combustion at ambient temperatures of -40°C and 85°C is less than 125 K.