Airbag inflators—also known as gas generators—are the core components that enable airbag deployment.
When a collision occurs, the inflator rapidly produces gas to fill the airbag cushion within 20–40 milliseconds.
Although compact, an inflator contains precise engineering, chemical formulations, and safety mechanisms.
This article explains the internal structure, working process, and common classifications of airbag inflators used in modern vehicles.
Most inflators share several essential components regardless of size or shape.
| Component | Description | Function |
|---|---|---|
| Initiator / Igniter | Electrical device that receives signal from SRS ECU | Starts the chemical reaction or gas release |
| Gas Generant (Propellant) | Solid chemical pellets | Burns rapidly to produce nitrogen gas |
| Filter / Cooling System | Metal mesh & chambers | Cools and cleans gas before entering airbag |
| Diffuser Housing | Outer metal shell with outlet holes | Directs gas into the airbag |
| Burst Disk / Seal | Thin sealed membrane | Breaks under pressure to release gas |
| Secondary Igniter (Dual-stage inflator) | Additional igniter | Controls second-stage inflation |
Inflators are designed to withstand extremely high temperature and pressure while maintaining safety during storage, transport, and operation.
Collision Detected
Sensors send signal to the SRS control unit.
Igniter Activation
The igniter receives an electrical current and starts combustion.
Chemical Reaction
Gas generant burns rapidly, producing high-pressure nitrogen gas.
Gas Filtration & Cooling
The hot gas passes through filters to reduce temperature and remove particles.
Burst Disk Opens
Pressure breaks the internal seal, releasing gas.
Airbag Inflation
Gas flows into the airbag cushion, deploying it within milliseconds.
This precise process is synchronized with seat belt pretensioner activation for optimal occupant protection.
Inflators are classified based on structure, deployment stages, and chemical composition.
| Type | Description | Features |
|---|---|---|
| Single-Stage Inflator | One igniter, one output stage | Common in older or low-cost models |
| Dual-Stage Inflator | Two igniters (independent or sequential) | Used in advanced SRS systems |
| Adaptive Multi-Stage | Multiple levels controlled by ECU | High-end U.S. & European vehicles |
| Type | Mechanism | Advantages |
|---|---|---|
| Pyrotechnic Inflator | Solid propellant burns to create gas | Compact, reliable, widely used |
| Stored Gas Inflator | Pre-filled compressed gas | Stable performance, no combustion |
| Hybrid Inflator | Combination of combustion + stored gas | Smooth inflation, used in curtain airbags |
| Application | Typical Inflator | Notes |
|---|---|---|
| Driver Airbag | Small pyrotechnic / hybrid | Usually 54–63 mm diameter |
| Passenger Airbag | Large pyrotechnic or hybrid | Higher gas volume |
| Side Airbag | Compact stored-gas | Fast deployment |
| Curtain Airbag | Long tubular hybrid inflator | Sustains inflation for rollover protection |
Airbag inflators must pass strict global standards:
FMVSS 208 / 214 (USA)
ECE R94 / R95 (Europe)
GB/T 19939 (China)
ISO 12097
| Parameter | Typical Value |
|---|---|
| Activation Time | 2–3 ms |
| Gas Output | 20–120 liters depending on airbag type |
| Operating Temperature | −35°C to +90°C |
| Storage Life | 10–15 years |
| Pressure Range | 20–300 bar depending on type |
Determines airbag deployment speed
Affects occupant protection level
Must remain stable for many years
Key to preventing over-inflation or under-inflation
Essential for compliance with global safety regulations
For manufacturers and repair markets, choosing a reliable inflator supplier ensures vehicle safety and reduces liability risks.
Airbag inflators may look simple but contain advanced engineering and strict safety requirements.
Understanding their internal structure and classification helps automakers, distributors, and repair shops select high-quality products that meet global standards.
Andaotong provides:
✔ Driver & passenger inflators
✔ Single-stage / dual-stage systems
✔ Sizes ∅54 / ∅60 / ∅62 / ∅59 mm
✔ For American, Asian, Middle Eastern, and Latin American vehicles
