Hydrate Gas Generant for Cool Combustion
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Solution Overview
Problem
Automotive inflatable restraint systems face challenges in achieving high gas output at low flame temperatures while maintaining performance across temperature extremes, with existing gas generants often resulting in excessive heat, burns, and increased system weight due to heat sink and filtration requirements.
Innovation Solution
A gas generant composition incorporating a thermally stable crystalline hydrate compound, such as copper phthalate hydrate, with a water release temperature of at least 140°C, which acts as a coolant and fuel, reducing flame temperature and sensitivity to temperature and pressure, thereby enhancing burn rate stability and gas yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional gas generants are used to achieve high gas output, then gas production is sufficient, but flame temperature becomes excessively high causing burns and requiring heavy heat sink and filtration systems
Solution Approach 1:
The patent changes the chemical composition parameters of the gas generant by incorporating specific hydrate compounds (copper phthalate, copper pyromellitate, copper fumarate, or copper 3-nitrophthalate) that release water at controlled temperatures (100-150°C). This parameter change in composition enables the system to maintain high gas output while reducing peak flame temperature through controlled water vapor release during combustion.
Solution Approach 2:
The hydrate compounds act as intermediary substances that mediate between the fuel and oxidizer components. During combustion, these intermediaries decompose to release water vapor, which serves as a cooling agent that reduces flame temperature without interfering with the overall gas generation process. The water release temperature of 100-150°C positions it as an optimal intermediary that activates before peak combustion temperatures.
2Object-affected harmful factors
If flame temperature is reduced to prevent burns, then safety improves, but gas output and mass flow rate decrease
Solution Approach 1:
The patent utilizes phase transitions of water within the hydrate structure. The hydrate compounds undergo decomposition phase transition at 100-150°C, releasing water vapor during combustion. This phase transition occurs at a temperature that allows cooling of the flame without significantly impacting the gas generation rate, as the water release is integrated into the combustion process rather than occurring separately.
Solution Approach 2:
The gas generant employs a composite material system combining traditional fuel and oxidizer components with hydrate compounds. This composite formulation creates a multi-functional material that simultaneously provides combustion reactions for gas generation and controlled water release for temperature regulation, achieving both safety and performance goals.
3Speed
If high gas output is achieved quickly, then inflation speed is sufficient, but temperature extremes cause performance variability
Solution Approach 1:
The hydrate compounds are pre-loaded into the gas generant formulation before use. The water release temperature of 100-150°C is deliberately selected to occur during the early-to-mid stage of combustion, providing proactive cooling before peak temperatures are reached. This preliminary cooling action ensures consistent performance across different ambient temperature conditions by stabilizing the combustion process.
Solution Approach 2:
The gas generant system is self-regulating through the inherent thermal properties of the hydrate compounds. As the combustion process generates heat, the hydrate automatically decomposes at its characteristic temperature range (100-150°C), releasing water vapor that cools the reaction zone. This self-service mechanism maintains performance consistency without requiring external control systems, ensuring reliable operation across temperature extremes from -40°C to 80°C.
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 solution enables a cool burning gas generant with reduced flame temperature, improved burn rate stability, and increased gas yield, minimizing the risk of burns and system weight, while maintaining performance across temperature extremes.
Implementation Method 1
a fuel comprising a thermally stable crystalline hydrate compound with a water release temperature of 100° C. to 150° C.
Implementation Method 2
measured by differential scanning calorimetry (DSC) with a heating rate of 5° C./minute
Implementation Method 3
a thermally stable crystalline hydrate compound with a water release temperature of greater than or equal to about 140° C.
Data Source
AI summary
A gas generant composition for an automotive inflatable restraint system is provided with a fuel having a thermally stable crystalline hydrate compound with a water release temperature of greater than or equal to about 140° C. The thermally stable crystalline hydrate compound serves as a ballistic modifier, which can serve to increase burn rate, reduce pressure sensitivity, reduce temperature sensitivity, and the like. The thermally stable crystalline hydrate compound may be selected from the group consisting of: a copper phthalate hydrate, copper pyromellitate dihydrate, copper fumarate dihydrate, copper (3-nitrophthalate) dihydrate, and combinations thereof.