Airbag Inflatable Duct Pressure Management
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Solution Overview
Problem
Existing airbag systems face challenges in achieving the necessary pressure differential between multiple chambers using a single inflator, leading to potential backflow and difficulties in inflating chambers to required pressures for effective impact protection.
Innovation Solution
The design incorporates an inflatable duct with valve sets that control the relative inflation rates and pressures of separate chambers, allowing one chamber to continue inflating after the other has reached its pressure, and minimizing fluid communication once the duct collapses to maintain pressure isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single inflator is used to deliver inflation gas to both chambers through a diffuser, then the device complexity is reduced, but the ability to achieve required pressure differentials deteriorates due to backflow
Solution Approach 1:
The airbag is divided into two separate chambers (first chamber and second chamber) with independent fluid communication paths through the inflatable duct. Each chamber can be inflated to different pressures independently, allowing the pelvis chamber to reach higher pressures while the thorax chamber maintains lower pressures, thus achieving the required pressure differential without backflow
Solution Approach 2:
The inflatable duct acts as an intermediary component between the single inflator and the two chambers. It provides controlled fluid communication pathways with valve sets that regulate gas flow to each chamber independently, enabling pressure differential achievement while using only one inflator
2Reliability
If the pelvis chamber is inflated to high pressure for firm protection, then the impact protection effectiveness is improved, but the thorax chamber cannot be maintained at low pressure due to backflow
Solution Approach 1:
The airbag is segmented into two independently controllable chambers with separate fluid communication pathways. The pelvis chamber can be inflated to high pressure for firm protection while the thorax chamber is maintained at low pressure through independent valve control, preventing backflow between chambers
Solution Approach 2:
Different regions of the airbag (pelvis vs. thorax chambers) are given different pressure characteristics tailored to their specific protection needs. The pelvis chamber receives high pressure for firm support, while the thorax chamber receives low pressure for soft cushioning, with each chamber's pressure independently controlled through its own valve set
3Stress or pressure
If valve sets are exposed to inflation gas during duct inflation, then independent pressure control is achieved, but the device complexity increases
Solution Approach 1:
The valve sets are integrated into the walls of the inflatable duct itself, combining the duct structure with the valve mechanism. As the duct inflates, the valve sets are naturally exposed to inflation gas through the duct wall, eliminating the need for separate valve housings or complex actuation mechanisms
Solution Approach 2:
The inflatable duct's own inflation process serves to expose the valve sets to inflation gas. The duct's expansion during normal operation automatically opens the valve pathways, using the system's own operational dynamics to achieve independent pressure control without external intervention
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 solution enables the airbag system to achieve the required pressure differentials between chambers, ensuring effective impact protection for both the pelvis and thorax regions by controlling the inflation rates and pressures independently, thereby preventing backflow and enhancing safety.
Implementation Method 1
The delivery of an inflation gas to the inlet causes the inflatable duct to inflate thereby exposing at least one of either the first valve set and the second valve set to the inflation gas
Implementation Method 2
a first valve set comprising at least one first valve providing fluid communication between the inflatable duct and the first chamber and a second valve set comprising at least one second valve providing fluid communication between the inflatable duct and the second chamber
Data Source
AI summary
An inflatable side airbag has an inflatable duct for the delivery of inflation gas. The inflatable duct of the inflatable side airbag provides for rapid deployment of a multi-chamber air bag while controlling the rate of inflation and the relative pressure of the chambers. The inflatable duct allows a single inflator to inflate a high pressure pelvis chamber and a lower pressure thorax chamber while preventing fluid communication between the two chambers upon completion of inflation.