Segmented Gas Generator Filtration for Controlled Airbag Combustion
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Solution Overview
Problem
Existing gas generators for vehicle safety systems face limitations such as limited filter capacity, restricted gas flow, high internal pressure, and uncontrolled combustion rate due to the design of filters at a fixed position at the combustion chamber end, leading to inefficient gas generation and potential safety issues.
Innovation Solution
A gas generator design with a combustion chamber divided into multiple portions by filter units, allowing for step-like burning of fuel bodies and delayed ignition, reducing internal pressure and optimizing filter capacity through the use of permeable filter units that separate fuel beds and control combustion rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter unit is positioned at the combustion chamber end at a fixed predetermined position, then the filter can withhold slag and fuel particles from the entire fuel bed, but the filter capacity is limited and the gas flow throughput is restricted by axial backflow
Solution Approach 1:
The fuel bed is divided into multiple segments separated by filter units positioned at different axial locations. Each segment burns independently and sequentially, allowing the filter units to process slag and particles from smaller fuel portions rather than the entire fuel bed at once. This segmentation increases both filter capacity utilization and gas flow throughput by eliminating the bottleneck of a single end-positioned filter handling all combustion products simultaneously.
2Device complexity
If a filter unit is positioned at the combustion chamber end, then the structure is simple, but the internal pressure becomes detrimentally high requiring heavier housing design
Solution Approach 1:
The combustion chamber is segmented into multiple portions by filter units positioned at different axial locations along the fuel bed. This segmentation creates multiple pressure relief zones where combustion gases can pass through filter units at intermediate positions rather than accumulating at a single end position. The distributed filter positions reduce peak internal pressure by providing multiple egress paths for combustion products, eliminating the need for heavier housing design.
3Productivity
If a long continuous fuel bed is ignited once at the start end, then the combustion proceeds at a predeterminable constant speed, but the combustion rate cannot be controlled or varied
Solution Approach 1:
The continuous fuel bed is segmented into multiple discrete fuel portions separated by filter units. Each segment can be ignited independently or in sequence, allowing control over the combustion rate and timing. The igniter can activate different segments at different times, enabling variable gas generation rates and combustion profiles that adapt to different operational requirements, rather than forcing a single constant-speed combustion through the entire fuel bed.
Solution Approach 2:
The segmented fuel bed structure enables periodic or sequential ignition of different fuel segments. The igniter can activate fuel portions in a controlled sequence rather than all at once, creating periodic combustion events that provide adaptable gas generation rates. This periodic action allows the system to modulate the overall combustion rate by controlling the timing and duration of individual segment ignitions.
4Quantity of substance
If the fuel bed extends continuously over a large axial length, then the gas generation volume is high, but the temperature band of the performance curve exhibits high spread with high variation
Solution Approach 1:
The long fuel bed is divided into multiple shorter segments separated by filter units. Each segment burns more uniformly and completely, producing consistent gas generation from each portion. The segmented structure ensures that no single location in the fuel bed becomes a bottleneck or creates excessive temperature variations, as each segment has its own filter unit positioned nearby to manage combustion products. This results in a more stable performance curve with reduced temperature band spread while maintaining high total gas generation volume.
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 achieves a more efficient gas generation rate with reduced variation, improved filter efficiency, and controlled pressure release, enhancing the safety and performance of vehicle safety systems.
Implementation Method 1
Within the combustion chamber at least one filter unit is arranged which divides the combustion chamber along a longitudinal axis of the gas generator into a first combustion chamber portion having a first number of first fuel bodies and at least one additional combustion chamber portion having an additional number of additional fuel bodies
Implementation Method 2
improved filter efficiency, and controlled pressure release
Data Source
AI summary
The invention relates to a gas generator (100), especially for a vehicle safety system, comprising an exterior housing (34), an igniter unit (38) having an igniter (42), a combustion chamber (14) having fuel bodies (18, 24), the combustion chamber being arranged axially downstream of the igniter unit (38), at least one filter unit (10) being arranged within the combustion chamber (14), which filter unit (10) divides the combustion chamber (14) along a longitudinal axis (La) of the gas generator (100) into a first combustion chamber portion (15) having a first number of first fuel bodies (18) and at least one additional combustion chamber portion (20) having an additional number of additional fuel bodies (24).