This document discusses the history and operation of airbags. It describes how airbags work by using sensors to detect impacts and inflate a nylon bag to prevent passengers from hitting hard surfaces. The document outlines the main airbag components like modules, sensors, and inflators. It also discusses limitations of airbags and applications beyond vehicles, such as airbag helmets and jackets.

2. CONTENTS
 History of Airbag
 Operation
 Limitations
 Airbag fatality statistics
 Applications
 Conclusion

3. Supplementary Restraint System for driver
and/or passenger safety in case of a crash.

4. HISTORY OF AIRBAG
 The airbag specified for automobile
use traces its origins as early as
1941
 First invented by Walter Lind and
John W. Hetrick
 At the beginning compressed air was
used

5. Types of Airbags
 Frontal Airbags
 Shaped airbag
 Side Airbag
 Side Torso Airbag
 Curtain airbag
 Knee Airbag
 Rear Curtain Airbag
 Centre Airbag

6. WORKING OF AIR BAG
Basic Mechanism
A thin nylon bag in the steering wheel /
above glove compartment inflates in the
event of an impact and prevents the
driver/passenger from hitting the steering
wheel/dashboard.

7. Main Components:
1) Airbag module
2) Diagnostic Unit
3) Crash sensors

8. Airbag Module
Contains both inflator unit and light-weight
fabric airbag and is located either inside:
1) Steering wheel hub
2) Above glove compartment
3) Near side compartment (as
separate/combined head/side/window-
curtain airbag)
Airbag: Thin nylon fabric bag folded neatly
into steering wheel that inflates to the size of
a large beach ball on impact.

9. Inflator unit:
 Contains a number of sodium azide pellets
which are electrically ignited to produce N2
that then fills the airbag. This is preferred to
storing compressed gas in the unit (space,
durability)

10. Diagnostic Unit:
Enables inflator unit and sensors when vehicle
is turned on, performs self check.
Constantly monitors airbag readiness and
indicates malfunctioning through an indicator
on dashboard
Usually stores electricity to activate airbag in
the event that a crash damages the battery /
link to battery

11. Sensors:
•Several crash sensors located in the front of
vehicle and in the passenger compartment.
•Each senses the sudden deceleration or
impact in the event of a crash and flips a
mechanical switch to indicate a crash.

12. Ball tube crash sensor

13. Airbag Deployment
Frontal crash scenario: Car crashes into an obstacle
(wall) at 20+ mph
Sensors detect the deceleration and inflator unit
activated
Deployment sensitivity: To guard against accidental
inflation on hard braking, sensors detect collisions into a
solid barrier at speeds greater than 8-14 mph only as
impacts

14. An electric current is used to heat a filament
wire that ignites the NaN3 capsules,
producing N2:
2NaN3  2Na + 3N2
10Na + 2KNO3 K2O + 5Na2O+ N2
K2O + Na2O SiO2 alkaline glass
(safe, unignitable)

15. Limitations ?

16. Airbag fatality statistics

17. Applications:
Airbag landing system

18. The Airbag Helmet
The unit is designed to shoot a protective,
inflatable nylon hood around the user’s head
within one tenth of a second of impact.

19. The Airbag Jacket
These jackets are designed to keep
motorcycle riders safe during a crash, and
typically have anchoring cables and a CO2
cartridge.

20. The Avalanche Airbag

21. The Cell Phone Airbag
• Honda teased tech aficionados with an idea of a
smartphone case that deploys an airbag when the phone
is accidently dropped.
• The case uses six small airbags placed around the
edges of the smartphone, which are deployed when the
case takes a spill.

22. Conclusion
Airbags are an effective secondary safety measure
that reduces the risk of injury for vehicle
occupants, in more severe collisions. RoSPA
supports the fitment of airbags in vehicles if they
are used in conjunction with - but not in place of -
seat belts.