Gas Generator Closure Deformation for High-Temperature Pressure Relief
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Solution Overview
Problem
Existing gas generators for airbag apparatuses face issues when exposed to high temperatures, as the pressure increase in the combustion chamber can lead to housing fracture due to the generation of combustion gas, and existing solutions like U.S. Pat. No. 6,447,008 are uncertain in operation and prone to sealing issues under high pressure.
Innovation Solution
A gas generator design featuring a combustion chamber, a pressurized gas chamber, and a diffuser chamber with a first and second closing member, where the first closing member can deform or move to allow communication between the combustion and diffuser chambers, preventing excessive pressure from building up and fracturing the housing, using a retainer or deformable member to facilitate this movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the combustion chamber is sealed to maintain pressure for airbag deployment, then the airbag can be effectively inflated, but the housing may fracture under high temperature due to pressure buildup from combustion gas
Solution Approach 1:
The combustion chamber is segmented into two separate closing members (first closing member and second closing member) instead of a single sealed structure. This segmentation allows one closing member to fail safely under high temperature while the other maintains the seal for normal operation, resolving the contradiction between maintaining pressure reliability and preventing housing fracture under heat stress
Solution Approach 2:
The first closing member is designed with a space for deformation or movement that is prepared in advance. Under high temperature conditions, this pre-designed space allows the first closing member to deform or move toward the combustion chamber, opening a communication path before the housing can fracture, thus preventing catastrophic failure while maintaining normal sealing function
2Strength
If the combustion chamber is made robust to withstand high pressure, then the housing can prevent fracture, but the pressure buildup from combustion gas cannot be released and may cause housing fracture
Solution Approach 1:
The first closing member acts as an intermediary safety mechanism between the combustion chamber and the housing. It is designed to deform or move under high temperature conditions, creating a communication path that allows combustion gas to escape. This intermediary structure protects the housing from direct exposure to excessive pressure buildup while maintaining the robustness needed to prevent fracture
Solution Approach 2:
The potential harmful effect of combustion gas pressure buildup is converted into a beneficial safety feature. The first closing member is designed to fail in a controlled manner (deformation or movement) under high temperature, transforming the harmful pressure into a controlled release mechanism that prevents housing fracture while maintaining the benefit of a robust housing structure
3Device complexity
If a single closing member is used to seal the combustion chamber, then the structure is simple, but it cannot provide both normal operation sealing and high temperature pressure relief
Solution Approach 1:
The single closing member is segmented into two distinct closing members with different functions. The first closing member is designed to deform or move under high temperature to provide pressure relief, while the second closing member maintains the seal for normal operation. This segmentation enables the system to adapt to different temperature conditions while maintaining reasonable structural complexity
Solution Approach 2:
The two closing members together provide multi-functionality: one closing member handles normal operation sealing while the other handles high temperature pressure relief. This universal design allows the combustion chamber to respond appropriately to different temperature conditions, achieving adaptability without excessive complexity
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
Ensures safe operation by allowing combustion gas to be discharged without excessive pressure on the housing, preventing fracture and ensuring reliable function even in high-temperature conditions like a fire.
Implementation Method 1
When an airbag apparatus including such a gas generator is placed in a high temperature state caused by fire or the like, a gas is expanded in the pressurized gas chamber to a high-pressure state
Implementation Method 2
the gas generating agent in the combustion chamber which is a closed space is eventually ignited and burned to generate a combustion gas
Data Source
AI summary
The present invention provides a gas generator, including; a combustion chamber accommodating an igniter and a gas generating agent; a pressurized gas chamber filled with a gas selected from a rare gas or a nitrogen gas; a diffuser chamber located between the combustion chamber and the pressurized gas chamber and provided with a gas discharge port;a first closing member closing between the combustion chamber and the diffuser chamber, a second closing member closing between the pressurized gas chamber and the diffuser chamber;the combustion chamber having at least one of a space in which the first closing member deforms or moves, and a member which forms the space for enabling the first closing member to deform or move,when the gas generator is placed in a high-temperature atmosphere, due to a pressure increase or an impact caused by the gas inflow into the diffuser chamber, the first closing member being deformed or the first closing member being moved toward the combustion chamber, thereby making the combustion chamber and the diffuser chamber communicate with each other and making an inside of the combustion chamber and an outside of the gas generator communicate with each other.