The document discusses airbags as a safety restraint system in automobiles. It begins by providing background on the development of airbags, noting they were created as a soft cushion to land against in a crash. The basics section explains how airbags work based on Newton's second law of motion to slow a passenger's speed to zero during a collision. The main parts of an airbag are described as the bag itself, made of thin nylon fabric, as well as sensors and an inflation system using hot nitrogen gas. The working section then outlines how the system detects a crash and ignites the nitrogen gas to rapidly inflate the airbag. Modern airbag types including side, curtain, and door airbags are also discussed.

1. AIRBAGS: A Safety Restraint
System of an automobile

2. INTRODUCTION
Seat belts provided the sole form of safety in
cars.
Airbags were developed.
A soft pillow to land against in a crash.
They are gas-inflated cushions.
The first patent on an inflatable crash landing
device was filed during World War II.
Airbags are the subject of serious scientific
research and tests.

3. BASICS OF AIRBAGS
Newton’s second law of motion.
If objects aren’t restrained they will continue
moving at the speed of the moving car even if
the car is stopped by a collision.
All airbags need to do is slow down the
passengers speed to zero.

4. MAIN PARTS OF AN AIRBAG
 Bag
Made of thin nylon fabric,folded into a steering wheel
or dashboard or more recently the door or seat.
 Sensor
Tells the bag to inflate
 Inflation system
The rapid pulse of hot nitrogen gas to inflate the bag.

5. WORKING
 During collision, a mechanical switch is flipped
and an electrical contact takes place.
 Sensors send an electric current to the inflation
system.
 Inflation system contains sodium azide and
potassium nitrate.
 Electric current heats the filament which ignites
the capsule containing Nitrogen gas.
 The gas expands quickly and inflation of air
bags takes place, which literally bursts from its
storage site in the steering wheel.

6. 2 NaN3 → 2 Na + 3 N2 (g)
10 Na + 2 KNO3 → K2O + 5 Na2O + N2 (g)
K2O + Na2O + 2 SiO2 → K2O3Si + Na2O3Si (silicate glass)

7. This is how it takes place..

8. MECHANICAL CRASH SENSORS
• CRASH SENSOR WITH DAMPING
BALL IN-TUBE SENSOR
THE AIRFLOW GENEARTES AN AERODYNAMIC DRAG FORCE THAT DAMPENS THE
BALL MOTION.

9. • SPRING MASS SENSOR
ROLOMITE SENSOR
Roller- suspended with a tensioned baned.
Substantial collision- roller overcomes a spring force and rotates forward.
Impact-moving contact of the metallic band touches a fixed contact and
closes a circuit.
Parameters- distance of trigger
- magnitude of the spring.

10. Future of airbags

Smart Restraint Systems
Adapts its geometry, performance or behavior
to suit various impacts and occupant position.
Includes weight sensors.
Determine type of occupant in the seat. i.e
child or adult.
Detect the distance of passenger from airbags.

11. MODERN TYPES OF AIRBAGS

Side air bag
Cars that currently offer side airbags represent
the new wave of occupant protection.
Provides protection during side collisons.
This prevents the airbag on the undamaged
side of the car from inflating.

12. 
Curtain airbags
Inflates in front of windows to provide
passengers better head and neck protection.
 More efficient at tipping and side impacts.

Door air bag
The door has more space, allowing for a
bigger bag that provides more coverage.
Developed by Ford and Renault.
Door-mounted side air bags must begin
deploying in mere 5 or 6 milliseconds!

14. Airbag checks
Turn the key and look at the dashboard to find
the airbag light on for 7-10 sec. & then it goes
off.
Problems occur when
• 1. Light does not come on.
• 2. If light does not go off after the period.
• 3. If light comes while driving.

15. CONCLUSIONS
Since safety of human life is of high priority,
Air bags are of greater importance in the
present vehicles.
Safety bags must be implemented for safe
riding and for saving precious lives.
Let’s hope every automobile manufacturer
implements the same.

16. References
[1] A Safety Restraint System of an Automobile.
Tasnim N. Shaikh et al. Int. Journal of Engineering Research and Applications www.ijera.com
Vol. 3, Issue 5, Sep-Oct 2013, pp.615-621
[2] A Treatise on crash sensing for automotive airbag systems IEEE /ASME transactions on
Mechatronics, Vol. 7, No. 2, JUNE 2002 by Ching-Yao Chan .

17. THANK YOU