Gas Generator Filter Placement for Rapid Pressure Rise
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Solution Overview
Problem
Existing gas generators for air bag systems face challenges in downsizing and achieving stable output performance due to inefficient filter placement and cooling efficiency, leading to delayed pressure increase and potential filter damage during actuation.
Innovation Solution
The gas generator design incorporates a filter positioned within the pressurized gas chamber to cover the second rupturable plate, allowing combustion gas to increase internal pressure promptly and ensuring the filter is used as a gas filling space, while also being attached to the diffuser portion to prevent detachment during actuation, using crimped wire filters for enhanced rigidity and fraying resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the filter is disposed outside the pressurized gas chamber, then the filter can be easily accessed and replaced, but the overall device size increases and cooling efficiency decreases
Solution Approach 1:
The filter is integrated inside the pressurized gas chamber, merging the filtration function with the gas storage space. This eliminates the need for separate external filter housing, reducing overall device volume while maintaining filtration capability.
Solution Approach 2:
The filter serves as an intermediary component that both cools the combustion gas and filters it simultaneously. By positioning the filter within the pressurized gas chamber, it acts as a heat sink for cooling while also capturing combustion residues.
2Temperature
If the filter is positioned to cover the first rupturable plate, then the filter can cool the combustion gas early in the process, but the pressure increase is delayed and second rupturable plate breakage is delayed
Solution Approach 1:
The filter is positioned to cover the second rupturable plate rather than the first, allowing combustion gas to first rapidly increase pressure in the pressurized gas chamber. The filter then acts as a preliminary cooling and filtration stage before gas discharge, optimizing the sequence of actions.
3Device complexity
If the filter is not securely attached to the diffuser portion, then the assembly is simpler, but the filter may detach during actuation
Solution Approach 1:
The filter incorporates a flange with circumferential engagement teeth that flexibly engage with corresponding features on the diffuser portion. This thin-film-like engagement structure provides secure attachment without complex fastening mechanisms, preventing filter detachment during actuation.
4Ease of manufacture
If conventional filters are used without crimped wire construction, then manufacturing is simpler, but the filters are more susceptible to fraying and damage from gas flow
Solution Approach 1:
The filter employs crimped wire construction, creating a composite structure where individual wires are interlocked through crimping. This composite approach enhances the filter's resistance to fraying and gas flow damage while maintaining manufacturability through standardized wire crimping processes.
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 enables a downsized gas generator with improved cooling efficiency, stable output performance, and effective filtration of combustion residues, ensuring prompt and reliable gas discharge while minimizing filter damage from gas flow.
Implementation Method 1
a filter (60) disposed in the pressurized gas chamber (20) to cover the second rupturable plate (58), the filter allowing, during actuation, combustion gas from the combustion chamber (30) and the pressurized gas to pass therethrough
Implementation Method 2
using crimped wire filters for enhanced rigidity and fraying resistance
Data Source
Figure 1~2(b)
Figure 3~4
Figure 5~6
AI summary
The present invention provides a gas generator (10), including: a pressurized gas chamber (20) formed by a cylindrical pressurized gas chamber housing(22) and being filled with the pressurized gas; a combustion chamber (30) connected to a first end portion of the pressurized gas chamber (20) and including an ignition device (34) and a gas generating agent (36) therein, a diffuser portion (50) connected to a second end portion of the pressurized gas chamber (20) and provided with a gas discharge port (52); a first rupturable plate(40)blocking a first communication passage (38)between the pressurized gas chamber (20) and the combustion chamber (30); a second rupturable plate (58) blocking a second communication passage (56) between the pressurized gas chamber (20) and the diffuser portion (50); and afilter (60) disposed and positioned in the pressurized gas chamber (20) to cover the second rupturable plate (58), the filter (60) allowing, during actuation, the combustion gas from the combustion chamber (30) and the pressurized gas to pass therethrough and be discharged therefrom in response to rupturing the second rupturable plate (58).