Less-Is-More Airbag Exploits Bernoulli Effect

Autoliv’s new Bernoulli Airbag fills larger airbag from a smaller inflator.

Dan Carney, Senior Editor

August 22, 2023

2 Min Read
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BERTRAND GUAY/AFP via Getty Images)

Swedish supplier Autoliv has developed a new airbag that leverages fundamental fluid dynamics to inflate larger airbags using a small single-stage inflator. The company is the world’s largest provider of airbag systems, modules, and components.

The Bernoulli Airbag meets FMVSS208 low-risk deployment requirements while filling a large 155-liter airbag from a compact single-stage inflator. It can do this because rather than generating all the gas needed to fill the bag, the Bernoulli Airbag draws in surrounding air in addition to the gas it generates.

Autoliv says this smaller inflator lets automakers shorten development time and reduce cost when deploying it in their vehicles.

“We have developed a way to inflate very large airbags, like the ones needed in newer electric vehicles with roomier cockpits and comfort seating, with a smaller single-stage inflator,” said Autoliv chief technical officer Jordi Lombarte. “Additionally, the Bernoulli Airbag generates less heat, is lighter, and can reduce customer development testing in the United States by more than 30 percent.”

You’ll recall that Swiss mathematician and physicist Daniel Bernoulli described fundamental principles of fluid dynamics that explain many phenomena such as how airplanes fly. Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure.

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Autoliv's Bernoulli Airbag.

Autoliv applies this theory to add outside air to the inflation gases generated by the Bernoulli Airbag’s inflator. It works like a carburetor, but rather than using airflow to draw in fuel, it pulls in more air.

The module fires inflation gases at supersonic speed through multiple inlet tubes to the airbag. As the gas flows through the tubes, it draws surrounding ambient air into the chamber with the gases, creating aspiration, and will inflate a much larger airbag with an even smaller inflator than required today.

Autoliv says the company will have the Bernoulli Airbag in production during the third quarter of 2023.

 

About the Author

Dan Carney

Senior Editor, Design News

Dan’s coverage of the auto industry over three decades has taken him to the racetracks, automotive engineering centers, vehicle simulators, wind tunnels, and crash-test labs of the world.

A member of the North American Car, Truck, and Utility of the Year jury, Dan also contributes car reviews to Popular Science magazine, serves on the International Engine of the Year jury, and has judged the collegiate Formula SAE competition.

Dan is a winner of the International Motor Press Association's Ken Purdy Award for automotive writing, as well as the National Motorsports Press Association's award for magazine writing and the Washington Automotive Press Association's Golden Quill award.

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He has held a Sports Car Club of America racing license since 1991, is an SCCA National race winner, two-time SCCA Runoffs competitor in Formula F, and an Old Dominion Region Driver of the Year award winner. Co-drove a Ford Focus 1.0-liter EcoBoost to 16 Federation Internationale de l’Automobile-accredited world speed records over distances from just under 1km to over 4,104km at the CERAM test circuit in Mortefontaine, France.

He was also a longtime contributor to the Society of Automotive Engineers' Automotive Engineering International magazine.

He specializes in analyzing technical developments, particularly in the areas of motorsports, efficiency, and safety.

He has been published in The New York Times, NBC News, Motor Trend, Popular Mechanics, The Washington Post, Hagerty, AutoTrader.com, Maxim, RaceCar Engineering, AutoWeek, Virginia Living, and others.

Dan has authored books on the Honda S2000 and Dodge Viper sports cars and contributed automotive content to the consumer finance book, Fight For Your Money.

He is a member and past president of the Washington Automotive Press Association and is a member of the Society of Automotive Engineers

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