What Are the Three Main Parts of an Airbag?

The three main parts of a modern automotive airbag are the airbag cushion (the fabric bag), the inflator (the gas generator), and the crash-sensing/control unit (the electronic module that decides when to deploy). Together, they detect a severe impact and deploy a protective cushion in milliseconds to reduce injury.

The Core Components at a Glance

Automakers and safety engineers typically describe the airbag system in terms of its three essential building blocks. Here is what each part does and why it matters.

• Airbag cushion: A tightly packed, woven-nylon (often silicone- or neoprene-coated) bag designed to deploy, absorb energy, and vent in a controlled way. It unfolds through a trim cover and helps manage the forces on a driver or passenger’s head and torso.
• Inflator: A device that rapidly produces gas—via a pyrotechnic propellant, a stored compressed gas, or a hybrid system—to fill the cushion in roughly 20–40 milliseconds. Contemporary inflators favor propellants like guanidine nitrate and hybrid designs, moving away from older sodium-azide chemistry.
• Crash-sensing/control unit (ACU): An electronic module with accelerometers and algorithms (often aided by satellite sensors) that interprets a crash, checks inputs such as seatbelt usage and occupant detection, and triggers the inflator when deployment thresholds are met.

Taken together, these parts form a closed loop: the ACU detects and decides, the inflator generates gas on command, and the cushion manages impact forces to help prevent serious injury.

How the Parts Work Together in a Crash

In the first milliseconds of a severe collision, the airbag control unit reads acceleration spikes and other sensor data. If the event exceeds calibrated thresholds, it sends an electrical signal to the inflator. The inflator then releases gas—chemically generated, stored, or both—into the folded cushion. The cushion bursts through its cover, inflates, and immediately begins venting through calibrated holes to manage deceleration forces. The sequence, from detection to full inflation, typically occurs within about 15–50 milliseconds, depending on the airbag type and vehicle calibration.

Materials and Design Details

The cushion is usually a high-strength woven nylon fabric with heat-resistant coatings to tolerate hot inflator gases. Its seams and venting are engineered to balance quick deployment with controlled deflation, helping to reduce peak forces on the occupant.

Inflators come in three broad types: pyrotechnic (chemical gas generation), stored-gas (compressed argon or nitrogen), and hybrid (combining a smaller pyrotechnic charge with stored gas). The industry has largely transitioned away from sodium-azide propellants due to toxicity and stability concerns, favoring alternative generants and improved moisture control to enhance long-term reliability.

The ACU fuses data from onboard accelerometers, sometimes pressure sensors, and satellite sensors near the vehicle’s extremities. It also references seatbelt status, occupant presence/weight, and seat position to tailor deployment—single- or multi-stage inflators and, in many vehicles, suppression if a seat is unoccupied or a child seat is detected.

Modern Variations and Safety Considerations

Beyond frontal airbags, vehicles may include side torso bags, side-curtain bags for head protection, knee airbags, and center airbags to mitigate occupant-to-occupant contact. All rely on the same three-part architecture: cushion, inflator, and sensing/control. Regular recall checks remain important; inflator-related recalls in the past decade prompted widespread replacements. Owners can verify their vehicle’s status using their VIN via national safety databases or their automaker’s website. As with any safety system, components should never be tampered with or serviced outside manufacturer procedures.

Summary

An airbag system’s three main parts are the cushion, the inflator, and the crash-sensing/control unit. The control unit detects a crash, commands the inflator, and the cushion deploys to manage impact forces—all in a fraction of a second. Advances in materials, inflator design, and sensing algorithms continue to refine how effectively these three elements work together to protect vehicle occupants.

What are the three parts of an airbag?

The airbag module contains both an inflator unit and the lightweight fabric airbag. The airbag system consists of three basic parts: (1) An airbag module, (2) crash sensors, and (3) a diagnostic unit. Some systems may also have an on/off switch, which allows the airbag to be deactivated.

What are airbags made up of?

Airbags are primarily made of a durable, tear-resistant, and heat-resistant woven Nylon (polyamide) fabric, such as Nylon 6 or Nylon 6.6, coated for gas impermeability. The fabric is treated to prevent sticking, often with a silicone coating for sealing and talcum powder or cornstarch for assembly, and a heat shield coating may be added to protect against high temperatures during deployment.
 
Fabric Components

• Nylon fabric: Woven from strong, lightweight, and flexible Nylon 6 or Nylon 6.6 yarns. 
• Coatings:
  • Silicone coating: Applied to seal the fabric and prevent gas from escaping. 
  • Heat shield coating: Applied near the inflator to protect the fabric from the heat of the rapid chemical reaction during deployment. 
• Anti-stick agents: Talcum powder or cornstarch coats the airbag fabric to prevent it from sticking together before deployment. 

Other Materials

• Inflator: Contains a solid propellant, such as sodium azide, which produces the rapidly expanding, non-toxic nitrogen gas needed to inflate the airbag. 
• Sensor: Detects a collision and triggers the ignition system to start the inflation process. 
• Plastic parts: The entire assembly is housed in a plastic module that breaks open upon inflation. 

What are the basics of airbags?

An airbag or supplemental inflatable restraint is a vehicle occupant-restraint system using a bag designed to inflate in milliseconds during a collision and then deflate afterwards. It consists of an airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor.

What is the basic airbag system?

Airbags are actually one component of a three (3) part system designed to protect occupants of motor vehicles when they are involved in collisions. The system is comprised of 1) an airbag module, 2) a crash sensor and 3) a diagnostic unit.