Cylindrical Diffuser for Inflatable Airbag Gas Generator
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Solution Overview
Problem
Inflatable safety restraint devices, such as airbags, face issues with snap-load stress on airbag fabric and seams due to the high heat and velocity of inflation gases, which can lead to material stress and potential failure.
Innovation Solution
A gas generator system comprising a cylindrical diffuser with radially extending holes and a slot to surround and diffuse the inflation gases, reducing direct flow paths to the airbag fabric and seams, thereby mitigating snap-load stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a fabric bag with vent holes is used as a gas diffuser, then inflation gases are diffused through the fabric bag, but the high heat and velocity of gases still cause snap-load stress on the airbag fabric and seams
Solution Approach 1:
The patent introduces a solid diffuser structure with controlled openings as an intermediary component between the gas generator and airbag fabric. This solid diffuser mediates the gas flow by providing a rigid framework that distributes gas pressure more evenly, preventing direct high-velocity gas impact on the flexible airbag fabric and reducing snap-load stress.
Solution Approach 2:
The diffuser incorporates a porous structure with multiple openings of varying sizes distributed across its surface. This porous design allows gas to pass through in a controlled manner, breaking up concentrated high-velocity jets into distributed lower-velocity flows, thereby reducing the harmful snap-load effect on the airbag material while maintaining effective inflation.
2Productivity
If inflation gases are directed directly to the airbag, then rapid inflation is achieved, but significant snap-load stress is imposed on the airbag fabric and seams
Solution Approach 1:
The diffuser structure segments the single high-velocity gas stream from the generator into multiple smaller gas streams through its array of openings. This segmentation maintains the overall inflation speed by providing multiple parallel gas flow paths, while each individual stream exerts reduced force on the airbag fabric, collectively distributing the load and preventing fabric failure.
Solution Approach 2:
The diffuser changes the physical parameters of the gas flow by reducing velocity and distributing pressure across multiple openings. The solid structure converts a concentrated high-velocity, high-pressure stream into multiple lower-velocity, distributed streams, maintaining inflation effectiveness while reducing the harmful snap-load parameters that cause fabric stress.
3Object-affected harmful factors
If a deflector surrounds a portion of the inflator, then some gas diffusion is achieved, but the diffusion effect is limited compared to a full cylindrical diffuser
Solution Approach 1:
The cylindrical diffuser structure serves multiple functions simultaneously: it provides comprehensive gas diffusion across all directions, acts as a structural support element, and distributes mounting loads evenly around the generator. This multi-functionality achieves superior gas flow distribution compared to partial deflectors without proportionally increasing complexity, as the cylindrical form provides complete 360-degree coverage.
Solution Approach 2:
The cylindrical (curved) geometry of the diffuser provides superior gas flow management compared to flat or angular partial deflectors. The curved surface naturally distributes gas flow in all radial directions, creating more uniform diffusion patterns. The cylindrical shape also provides structural strength to contain gas pressure while maintaining a compact form factor.
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 diffuser system effectively reduces snap-load stress on airbag materials, allowing for the use of less expensive fabrics and improving airbag integrity by directing and diffusing inflation gases more evenly.
Implementation Method 1
A plurality of holes radially extend through the cylindrical sidewall to diffuse inflation gases generated by the inflator
Data Source
AI summary
A gas generator including a diffuser for diffusing inflation gases generated by an inflator of the gas generator. The gas generator includes at least a first mounting stud. The diffuser has a cylindrical sidewall axially extending between first and second axial ends and circumferentially extending between first and second axially extending sides. A gap is defined between the first and second axially extending sides. The cylindrical sidewall includes a plurality of holes radially extend therethrough and includes a slot having a closed end and an open end. The diffuser circumferentially surrounds a portion of the cylindrical housing of the inflator with the first mounting stud disposed in the slot.