Explain the difference between active and passive
restraint systems.
Describe the function and operation of air bags.
List the major parts of a typical air bag system.
The correct answer and explanation is:
Difference Between Active and Passive Restraint Systems
Active Restraint Systems: These require the occupant to take some action to use them. For example, seat belts must be buckled manually by the user to provide protection.
Passive Restraint Systems: These operate automatically without requiring user action. Examples include airbags and automatic seat belts. These systems deploy or function without conscious effort when a crash occurs.
Function and Operation of Air Bags
Airbags are passive restraint systems designed to protect occupants during a collision by providing a cushioning effect. They reduce the risk of severe injuries by absorbing impact energy and preventing contact with hard surfaces inside the vehicle, such as the dashboard or steering wheel.
How Airbags Work:
- Collision Detection: Sensors detect rapid deceleration or collision forces.
- Signal Transmission: The sensor sends a signal to the airbag control module.
- Gas Inflation: An igniter triggers a chemical reaction, rapidly generating gas (usually nitrogen or argon) to inflate the airbag.
- Deployment: The airbag deploys in milliseconds, creating a cushion between the occupant and the vehicle’s interior.
- Deflation: Small vent holes in the airbag allow it to deflate immediately after deployment, enabling occupants to move freely.
Major Parts of a Typical Airbag System
- Airbag Module:
- Contains the airbag cushion, inflator, and housing.
- Crash Sensors:
- Detect impact forces and send signals to trigger the airbag deployment.
- Airbag Control Module (ACM):
- Processes data from sensors and determines if deployment is necessary.
- Inflator:
- Generates gas to inflate the airbag.
- Wiring Harness:
- Connects components and transmits electrical signals.
- Diagnostic Indicator:
- Monitors system health and alerts the driver to malfunctions.
- Clockspring:
- Maintains electrical connections for the driver’s airbag in the steering wheel.
These components work together to ensure timely and effective airbag deployment in a collision.