Gas Generator Storage Chamber for Endothermic Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas generators for inflating motor vehicle airbags face issues with heavy and bulky filters that absorb energy without contributing to inflation, and the use of moveable parts like pistons complicates implementation and increases costs, while controlling gas temperature and gas loss remains challenging.
Innovation Solution
A gas generator design featuring a storage chamber for a liquid material that changes state endothermically under the effect of combustion gases, without using moveable parts, where the gas flow opens the storage chamber, allowing the liquid to escape and vaporize, reducing gas temperature and generator mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal filter is used to cool and filter combustion gases, then gas temperature is reduced and particles are filtered, but the filter becomes heavy and bulky and absorbs energy that could be used for airbag inflation
Solution Approach 1:
The patent uses water stored in the combustion chamber that undergoes phase transition from liquid to vapor when exposed to hot combustion gases. This phase change absorbs heat from the gases, cooling them effectively. The water vapor then mixes with the combustion gases and is expelled together to inflate the airbag, eliminating the need for a separate metal filter while achieving both cooling and particle filtration functions.
Solution Approach 2:
The combustion chamber serves multiple functions: it burns the pyrotechnic charge to generate expansion gases, stores water for cooling, and acts as the cooling mechanism itself through the phase transition of water. This self-service approach eliminates the need for a separate filter component, reducing weight and complexity while maintaining the cooling function.
2Temperature
If a piston or deformable chamber is used to expel water under combustion pressure, then water is effectively delivered to cool the gases, but the device complexity increases and implementation becomes more difficult
Solution Approach 1:
The patent removes the piston or deformable chamber mechanism from the system. Instead of using an active expulsion mechanism, the water is simply stored in the combustion chamber and allowed to be expelled passively by the pressure of combustion gases and water vapor themselves, significantly simplifying the device structure.
Solution Approach 2:
The combustion chamber is designed with specific geometric features including a conical bottom and strategically positioned openings (first opening for water entry, second opening for gas exit). This segmentation of functions within the chamber geometry allows water and gases to be properly managed without requiring complex mechanical components.
3Quantity of substance
If combustion chamber volume is increased to accommodate water storage, then sufficient water is available for cooling, but the generator length increases
Solution Approach 1:
The patent employs a conical bottom geometry in the combustion chamber, transitioning from a simple cylindrical shape. This dimensional change in the chamber geometry allows for more efficient space utilization, enabling adequate water storage volume within a more compact overall generator length by optimizing the three-dimensional arrangement of internal components.
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 design effectively lowers gas temperature to protect airbag materials, reduces generator mass, and simplifies operation by eliminating moveable parts, while minimizing gas loss, achieving efficient airbag inflation.
Implementation Method 1
a storage chamber for a material able to be released from said chamber under the effect of the combustion of said pyrotechnic charge, to change state endothermically under the effect of the gasses coming from this combustion
Implementation Method 2
the liquid to escape and vaporize, reducing gas temperature
Implementation Method 3
a combustion chamber containing at least one pyrotechnic charge able to be ignited by an initiator
Implementation Method 4
the hot gases given off by the combustion of the pyrotechnic charge provoke an increase in pressure in the combustion chamber
Implementation Method 5
The filter located inside the latter makes it possible to filter particles contained in the gases and also makes it possible to cool the exiting gases, due to its substantial thermal exchange surface
Data Source
Figure 1~2
Figure 3~5
Figure 6a~6b
AI summary
This invention relates to a gas generator which includes a case (1), in which is enclosed a combustion chamber (3) containing at least one pyrotechnic charge (30), a diffusion chamber (4), as well as a chamber (6) for storing a material (M) able to be released from said chamber (6) under the effect of the combustion of said charge (30), to change state endothermically under the effect of the gas coming from this combustion then be evacuated via said diffusion chamber (4), wherein the material (M) is a liquid stored at atmospheric pressure, said chamber (6) has at least one inlet opening (52), as well as a series of outlet openings (53), the latter are arranged within a wall (50) separating the chamber (6) from the diffusion chamber (4).