Hybrid Inflator Shock Wave Amplification
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Solution Overview
Problem
Existing hybrid inflators require expensive high-pressure igniters and thick combustion chamber walls to generate a robust shock wave for opening the bursting disk, which increases costs and complexity.
Innovation Solution
A hybrid inflator design that includes a combustion chamber with a propellant charge and an igniting unit, featuring a bursting element and a restraint element to create a shock gas volume that acts as a gas pressure spring, increasing the shock wave intensity and allowing for a robust opening of the bursting disk without the need for high-pressure igniters or thick walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the bursting pressure of the bursting membrane is increased to generate a robust shock wave, then the shock wave intensity is sufficient to open large hybrid inflators, but the combustion chamber wall thicknesses must be massively reinforced and the igniter chamber pressures must be appropriately high
Solution Approach 1:
The patent applies preliminary action by pre-positioning a shock wave generator element at the discharge end of the combustion chamber, ahead of the propellant charge. This element is prepared in advance to receive and amplify the shock wave generated by propellant ignition, thereby intensifying the shock wave without requiring increased combustion chamber pressure or wall thickness. The shock wave generator is pre-configured with a specific geometry (such as a conical or curved surface) that focuses and amplifies the shock wave as it propagates through the gas supply chamber.
Solution Approach 2:
The patent introduces an intermediary element - the shock wave generator - positioned between the propellant charge and the gas supply chamber. This intermediary receives the shock wave from the propellant ignition and transforms/amplifies it before it enters the gas supply chamber. The shock wave generator acts as a mediator that converts the relatively weak shock wave from low-pressure ignition into a robust shock wave capable of opening large inflators, without requiring high ignition pressure or thick combustion chamber walls.
2Force
If high-pressure igniters with increased amount of pyrotechnics are used to generate robust shock wave, then the shock wave intensity is sufficient, but the igniters become very expensive
Solution Approach 1:
The shock wave generator serves as an intermediary that amplifies the shock wave from a simple, low-cost igniter. Instead of using an expensive high-pressure igniter, the system uses a basic igniter to initiate combustion, and the shock wave generator (with its specific geometric configuration) amplifies the resulting shock wave to the required intensity. This separates the ignition function from the shock wave intensification function, allowing each to be optimized independently.
Solution Approach 2:
The patent replaces the need for high-pressure mechanical/chemical ignition systems with a geometrically-based shock wave amplification system. Instead of relying on increased igniter pressure or more pyrotechnics (mechanical/chemical approach), the system uses the geometric configuration of the shock wave generator (aeroshape, conical surface, or curved structure) to amplify the shock wave. This substitutes a complex high-pressure ignition system with a simpler geometric amplification structure.
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 effectively generates a stable and intense shock wave to open the bursting disk, reducing the need for expensive igniters and high combustion chamber pressures, thereby simplifying and cost-reducing the hybrid inflator system while maintaining robust functionality.
Implementation Method 1
The shock wave generated in this way is sufficient to open also large hybrid inflators... The shock wave formed by opening the bursting membrane is intended to safeguard robust opening of the end-side bursting disk
Implementation Method 2
a shock gas volume which in the activated state of the hybrid inflator acts on the bursting element like a gas pressure spring
Implementation Method 3
The ignition of the propellant provided in the combustion chamber results in sudden pressure increase in the combustion chamber so that the bursting membrane is destroyed or is abruptly opened
Implementation Method 4
The ignition of the propellant provided in the combustion chamber results in sudden pressure increase in the combustion chamber
Data Source
AI summary
The invention relates to a hybrid inflator (10) includes at least one combustion chamber (15) in which propellant charge is arranged and which has a discharge end (20), the propellant charge being formed of at least one propellant element (26), at least one igniting unit (12) by which the propellant charge can be ignited. The hybrid inflator (10) also includes at least one bursting element (14, 14′, 14″) which in the inactivated state of the hybrid inflator (10) delimits the combustion chamber (15) against a gas supply chamber (16) at the discharge end (20). The bursting element (14, 14′, 14″) and a restraint element (18, 18′, 18″) maintain the propellant charge in its position and/or the bursting element (14, 14′, 14″) and the propellant charge delimit a shock gas volume (SGV), wherein in the activated state of the hybrid inflator (10) the shock gas volume (SGV) acts on the bursting element (14, 14′, 14″) like a gas pressure spring.