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How Do Airbags Work?

Car accident lawyers know that airbags save lives. Airbags are a standard safety feature in every modern car. An airbag inflates during a collision, with a safe amount of force (according to regulations) before it deploys. It inflates faster than you can blink your eye. It is designed that way to catch up with the rate of speed that your head is likely to hit the steering wheel or dashboard.

Parts of an Airbag

The airbag restraint system (ARS) is a complex system that has many parts. We will only discuss the most important parts.

The first one is the airbag module. It is the part that has the pillow or the airbag, the inflator that causes the airbag to expand, the gas that inflates the airbag, and the container that is compact enough to hold both of them. The airbag module has to be small enough to fit inside the steering wheel.

Next, you have the airbag sensors. This is the computer that processes the crash impact and makes the decision whether to inflate the airbag or not. If this fails, the airbag will not inflate. A defective sensor will also cause the airbag to deploy unnecessarily, which can cause an accident.

In most cars, the sensors or brains are found in the box between the driver and passenger’s seat. The sensors diagnose electrical signals that run within the airbag system. It is similar to black boxes found in airplanes. These sensors record data that allows authorities to analyze details about the crash.

There is a clockspring that controls the amount of electricity that flows in the airbag system. The electrical current needs to flow in the steering wheel to the airbag module to release the gas and deploy the airbag. If this is defective, the airbag will never inflate.

Lastly, one new technology found in airbags today is the passenger detection system. This is a group of sensors that detects the presence of a passenger and measures his weight. The brains of the airbag system know if the passenger’s seat is empty. Thus, it will not deploy. Additionally, the system will also know to what extent the airbag should be deployed, or what amount of force it needs in proportion to the passenger’s or driver’s weight. As car accident lawyers know, these new safety features were necessary because old airbag systems deployed with so much force that they caused serious injuries, if not death, to the passenger.

Phases of Airbag Inflation

All the components of the airbag work in a specific order to deploy it properly. If one fails, the entire system fails. The sequence is shown below.

  • Impact Detention – In a crash, the collision sensors in your car will detect the impact and send the data to the ECU or Electric Control Unit, found in the airbag sensors. Crash sensors are found outside the car, in your bumper and on the sides the door.
  • Impact Evaluation – The force of impact is calculated and analyzed. This goes to the ECU found between the driver and passenger, even if the car is hit on its side. If the ECU determines the impact to be serious, it sends a signal to the gas inflator found in the airbag module.
  • Gas Emission – The airbag module receives a signal from the ECU, telling it to release the gas. The gas inflator starts a chemical reaction which releases gas to the airbag pillow, and it balloons quickly. The chemical that is used here is called sodium azide. This is a gas that rapidly expands when ignited.
  • Airbag Deployment – As the collision forces the car to stop, the driver’s head is propelled forward. Before this happens, the airbag should be fully inflated, thus preventing the driver’s head from hitting the hard steering wheel. All of these happen within 20 to 30 milliseconds. Once the force is fully absorbed, the airbag begins to deflate.

In a crash where the airbag did not deploy, it is best to speak to experienced car accident lawyers. They specialize in investigating car mishaps, including a defective airbag. As a consumer, you have all the right to demand justice from the airbag and car manufacturers because the law mandates that they only sell cars that comply with the highest standards of safety.

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