Gas Generator Partition Wall Flame Propagation
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Solution Overview
Problem
Existing gas generators for airbag systems face challenges in achieving efficient ignition and charging of gas generating agents due to limitations in the design of the cylindrical housing and partition walls, which affect the combustion process and airbag inflation efficiency.
Innovation Solution
A gas generator design featuring an axially-movable metallic partition wall with through-holes and a metallic annular member around the ignition portion, enhancing ignition ability and charging operability by facilitating uniform distribution of gas generating agents and improving flame propagation within the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cylindrical housing with an elongated combustion chamber is used, then the gas generator structure is simple and manufacturable, but the ignition ability and flame propagation efficiency are insufficient
Solution Approach 1:
The combustion chamber is segmented into multiple regions by partition walls with through-holes, creating a multi-zone combustion structure. This segmentation allows flame to propagate through the partition walls, improving ignition efficiency while maintaining the overall cylindrical structure for ease of manufacture
Solution Approach 2:
The partition walls are equipped with through-holes at specific locations to enhance flame propagation in critical areas. The igniter is positioned to protrude toward the partition wall, creating localized high-temperature zones that improve ignition ability without changing the overall cylindrical housing design
2Reliability
If a partition wall with through-holes is introduced to improve flame propagation, then ignition ability is enhanced, but the device complexity increases
Solution Approach 1:
The partition walls serve multiple functions: they structurally divide the combustion chamber, provide pathways for flame propagation through their through-holes, and support the gas generating agent. This multi-functionality reduces the need for additional components, thereby limiting the increase in device complexity
Solution Approach 2:
The gas generator employs a composite structure combining the cylindrical housing, partition walls with through-holes, and gas generating agent. This composite design integrates multiple functions into a unified structure, improving flame propagation while controlling overall complexity
3Reliability
If the igniter protrudes toward the partition wall to improve ignition, then flame propagation is enhanced, but the risk of direct flame contact with the partition wall increases
Solution Approach 1:
The partition wall with through-holes acts as an intermediary structure between the protruding igniter and the combustion chamber. The through-holes allow controlled flame passage while the partition wall material protects against direct flame damage, mediating the interaction between igniter and combustion environment
4Ease of operation
If a metallic annular member is added around the ignition portion, then assembling operability is improved, but the weight of the gas generator increases
Solution Approach 1:
The metallic annular member is designed to be axially movable, allowing it to be easily positioned and adjusted during assembly. This dynamic capability improves assembling operability while the limited displacement requirement keeps the component size and weight minimal
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 design improves ignition ability and assembling operability, reducing the weight of the gas generator while ensuring efficient airbag inflation by optimizing the partition wall structure and using a combination of annular members to enhance flame and gas distribution.
Implementation Method 1
the chamber contains, adjacent to the sealed generant cartridge, a coolant cartridge such as to form a coolant chamber... by the pressure within the sealed generant cartridge, central side portions and shear, rupture or otherwise permit the passage of the hot gas from the gas generant cartridge into the coolant cartridge
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
The present invention provides a gas generator wherein a diffuser portion having a gas discharge port is disposed at one end of a cylindrical housing; an ignition device is disposed at the other end of the cylindrical housing; an axially-movable metallic partition wall having a plurality of through-holes is disposed between the ignition device and the diffuser portion; a space between the partition wall and the ignition device is an ignition device chamber charged with a molded article of a first gas generating agent; a space between the partition wall and the diffuser portion is a combustion chamber charged with a molded article of a second gas generating agent; the partition wall has a circular bottom surface and an annular wall extending, in a single direction, perpendicularly to an outer circumference of the circular bottom surface, and the circular bottom surface is disposed so as to be on the diffuser portion side; the ignition device has an igniter having a disk-shaped ignition portion protruding toward the partition wall and a metallic annular member having an annular wall and disposed around the ignition portion; and the annular wall of the annular member protrudes to the partition wall further than the distal end surface of the ignition portion.