Airbag Vent Passage Using External Air for Cooler Inflation
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Solution Overview
Problem
Existing airbag systems face challenges in preventing damage to the airbag cushion due to high-temperature and high-pressure gases generated by the inflator, and they struggle to inflate large volume airbags without increasing the inflator's capacity, leading to higher manufacturing costs and weights.
Innovation Solution
The airbag device incorporates an inflator, a retainer, and an airbag housing with external air holes. The retainer covers the inflator and forms a passage for the gas to flow at high speed, while the airbag housing has external air holes that allow external air to be introduced into the passage, reducing the gas temperature and enabling larger volume inflation without increasing the inflator's capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the airbag cushion is reinforced with multiple layers of reinforcing material to withstand high temperature and pressure, then the airbag cushion can resist damage from the gas, but the manufacturing cost and weight of the airbag increase excessively
Solution Approach 1:
The patent introduces external air through air holes in the airbag housing, allowing the harmful high-temperature gas to mix with cooler external air. This converts the harmful thermal effect into a beneficial cooling mechanism, reducing the temperature of the gas before it contacts the airbag cushion, thereby eliminating the need for excessive reinforcing materials and reducing weight.
Solution Approach 2:
The patent uses external air as an intermediary substance that mediates between the high-temperature gas and the airbag cushion. The external air mixes with the hot gas in the passage, acting as a thermal buffer that reduces the temperature before the gas reaches the airbag cushion, thus protecting it without requiring heavy reinforcement.
2Volume of stationary object
If a larger capacity inflator is used to inflate a larger volume airbag, then the airbag can achieve the required volume, but the manufacturing cost and weight of the airbag system increase
Solution Approach 1:
The patent merges the gas from the inflator with external air from the surrounding environment. By combining these two gas sources in the passage, the system achieves a larger total volume of gas to inflate the airbag cushion without requiring a proportionally larger inflator, thereby reducing the weight and cost of the inflator while achieving the desired airbag volume.
Solution Approach 2:
The patent introduces external air through air holes in the airbag housing, utilizing the spatial dimension outside the inflator to obtain additional gas volume. This external air source provides an additional dimension for gas supply, allowing the airbag to achieve larger volume without increasing the inflator's internal capacity.
3Speed
If the gas generated from the inflator is supplied directly into the airbag cushion, then the airbag can be inflated quickly, but the high temperature and pressure of the gas may damage the airbag cushion
Solution Approach 1:
The patent performs preliminary cooling of the gas by introducing external air through air holes in the airbag housing before the gas reaches the airbag cushion. This preliminary action occurs in the passage where external air mixes with the hot gas, reducing its temperature in advance, so that when the gas contacts the airbag cushion, it is already at a safe temperature that prevents damage while maintaining quick inflation.
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 effectively reduces the temperature of the gas filling the airbag cushion, preventing damage and allowing for the inflation of larger volume airbags without increasing the inflator's capacity, thus reducing manufacturing costs and weight.
Implementation Method 1
a pressure difference occurs where the pressure at the first end of each external air hole that is connected to the passage becomes lower than the surrounding pressure according to Bernoulli's law
Implementation Method 2
as the external air at a relatively low temperature is introduced into the airbag cushion with the gas of the inflator, the temperature of the gas filled in the airbag cushion is reduced
Data Source
AI summary
An airbag device includes an inflator to discharge a gas; a retainer configured to cover the inflator and to define a passage to linearly guide the gas; and an airbag housing having external air holes to allow external air to be supplied into the passage by the gas passing through the passage at high speed. The external air holes are disposed at a middle portion of the passage.