Gas Generator Combustion Chamber Segmentation for Elongated Airbag Designs
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Solution Overview
Problem
Existing gas generators for lateral collision air bags face issues with incomplete combustion and pressure buildup due to the gas generating agent burning first, leading to potential component failure and inefficient gas flow, especially in elongated designs.
Innovation Solution
A gas generator with a tubular housing and a tubular member that includes an ignition device at one end and a diffuser portion at the other, featuring first and second gas passage holes and an opening portion that allows combustion gas to flow back into the combustion chamber, enhancing ignition and combustion efficiency by reducing blockages and improving gas discharge timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the gas generator is designed in an elongated shape to meet attachment location restrictions, then the device can be installed in limited spaces, but the gas generating agent burns first causing pressure buildup and incomplete combustion
Solution Approach 1:
The gas generator is divided into multiple combustion chambers separated by partition walls with communication holes. This segmentation allows different zones to burn the gas generating agent simultaneously or sequentially, preventing pressure buildup in any single chamber and ensuring complete combustion across the entire generator.
Solution Approach 2:
The tubular member is nested inside the tubular housing, creating a compact elongated structure that fits attachment location restrictions while maintaining internal combustion chambers. The nested design allows the combustion chambers to be arranged along the length of the generator without increasing overall volume excessively.
2Speed
If the gas generating agent burns first, then gas is generated quickly to inflate the air bag, but the gas passes through unburned agent causing flow blockage and pressure increase
Solution Approach 1:
The combustion chamber is divided into multiple zones separated by partition walls with communication holes. Gas can flow through these holes from one zone to another, preventing blockage by unburned agent in any single zone while maintaining rapid overall gas generation.
Solution Approach 2:
The partition walls with communication holes are pre-positioned to guide gas flow through specific paths. This preliminary arrangement ensures that gas flows through burned regions rather than unburned agent, preventing flow blockage before it occurs.
3Ease of manufacture
If the gas generator uses a simple tubular design, then the structure is simple to manufacture, but the ignition and combustion performance is insufficient
Solution Approach 1:
The tubular member is divided into multiple combustion chambers by partition walls, which can be manufactured as a single integrated piece or assembled from separate sections. This segmentation improves combustion performance while maintaining manufacturing simplicity through standardized components.
Solution Approach 2:
The tubular member serves multiple functions: it contains the gas generating agent, provides structural support, creates combustion chambers through partition walls, and guides gas flow through communication holes. This multi-functionality maintains structural simplicity while improving ignition and combustion performance.
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 the overall combustibility of the gas generating agent and ensures smooth gas flow, preventing blockages and advancing gas discharge timing, even in elongated housings with a length-to-diameter ratio of 4 or more, thereby enhancing the gas generator's performance and reliability.
Implementation Method 1
an ignition device (16) attached to one end of the housing (10), a combustion chamber (25) provided in an inside of the tubular member (30) for accommodating a gas generating agent (90) that generates a combustion gas
Implementation Method 2
a tubular gap (35) leading to a gas discharge port (15) is formed, the first gas passage hole (37), the second gas passage hole (39) and the opening portion (38) communicating the combustion chamber (25) with the tubular gap (35)
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3~4
AI summary
Gas generator including: a tubular housing (10), an ignition device (16) attached at one end and a diffuser (12) having a gas discharge port (20), attached at the other end, a tubular member (30), being disposed inside the tubular housing (10) and a tubular gap (36) leading to the gas discharge port is formed, a combustion chamber (25) provided inside the tubular member (30) for accommodating a gas generating agent, a first gas passage hole and a second gas passage hole formed on the first end side and the second end side, respectively, and an opening portion formed between the first gas passage hole and the second gas passage hole, such that they are communicating the combustion chamber (25) with the tubular gap (36), a projecting portion (50) provided in the opening portion such that the projecting portion projects into at least one of the combustion chamber (25) and the tubular gap (36).