Airbags | How do they work?

Summary

This video explains the life-saving technology behind airbags, detailing their evolution from early designs using compressed air to modern systems powered by chemical reactions. It highlights the engineering challenges involved in reducing injury during high-speed accidents and the breakthroughs made by Allen K. Breed, including the use of sodium azide to rapidly inflate airbags. The video also covers the safety issues surrounding sodium azide, such as the Takata recall, and how advancements in sensor technology have improved crash detection. Finally, it emphasizes the importance of wearing seatbelts to ensure the airbag functions effectively and safely.

Takeaways

• 😀 Airbags are crucial for preventing severe injury in high-speed accidents by cushioning the impact and preventing head injuries.
• 😀 Modern seatbelts are designed to slightly release tension in a crash, reducing internal injuries caused by excessive chest force.
• 😀 The initial airbag designs using compressed air failed because they were too slow and inaccurate in detecting crashes.
• 😀 Mr. Allen K. Breed's breakthrough involved using a ball-and-tube sensor to trigger airbags more accurately during collisions.
• 😀 Sodium azide was used to inflate airbags rapidly by converting into nitrogen gas, but it posed risks due to toxicity and moisture sensitivity.
• 😀 The infamous Takata airbag recall was caused by the absorption of moisture by sodium azide, leading to violent explosions and passenger injuries.
• 😀 Guanidine nitrate has replaced sodium azide in modern airbags, offering a safer, less toxic, and moisture-resistant alternative.
• 😀 MEMS sensors and advanced ECUs are now used to more accurately detect crash severity, ensuring airbags deploy at the right moment and with the correct force.
• 😀 Airbags inflate at speeds of up to 320 km/h, making it dangerous if they deploy when the driver isn't wearing a seatbelt.
• 😀 Modern airbags not only inflate but also deflate in a controlled manner, slowing the occupant's movement and reducing impact forces.
• 😀 Continuous innovation in airbag technology has significantly improved vehicle safety, with new materials and sensors addressing previous design issues.

Q & A

What is the main engineering challenge in a high-speed accident?

The main challenge is bringing the human body to rest from a high speed within 100 milliseconds without causing significant harm to the body.

How do seat belts protect the body in a crash?

Seat belts prevent excessive movement of the upper body during a crash, but they can exert large forces on the chest area, potentially causing internal injuries.

What is the role of airbags in vehicle safety?

Airbags cushion the impact during a crash and prevent the occupant from hitting the dashboard, reducing the risk of injury.

Why was the first airbag design using compressed air unsuccessful?

It failed because the compressed air system couldn't fill the airbag quickly enough, and the sensor wasn't precise enough to detect crashes accurately.

What innovation did Allen K. Breed contribute to airbag technology?

Allen K. Breed improved crash detection with a ball and tube sensor and introduced sodium azide as a chemical for inflating airbags quickly.

How does sodium azide work to inflate an airbag?

When triggered by heat, sodium azide rapidly converts into nitrogen gas, inflating the airbag within milliseconds.

What problem arose from using sodium azide in airbags?

Sodium azide could absorb moisture, which could cause dangerous, violent explosions when the airbag was triggered, leading to the Takata airbag recall.

How was the toxicity of sodium azide addressed in airbag design?

To reduce toxicity, potassium nitrate and silicon dioxide were added, and sodium azide was later replaced by guanidine nitrate, which is less toxic and less sensitive to moisture.

What issue did older airbag sensors face during accidents?

Older sensors could not distinguish between a crash and other events like potholes, which led to false airbag deployments.

How do modern airbags detect a crash more accurately?

Modern airbags use MEMS sensors and advanced electronic control units that evaluate the crash's severity based on inputs from various sensors, ensuring accurate deployment timing.