air bag
TRANSCRIPT
CONTENTS
History of Airbag
Operation
Limitations
Airbag fatality statistics
Applications
Conclusion
Supplementary Restraint System for driver
and/or passenger safety in case of a crash.
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
Types of Airbags
Frontal Airbags
Shaped airbag
Side Airbag
Side Torso Airbag
Curtain airbag
Knee Airbag
Rear Curtain Airbag
Centre Airbag
WORKING OF AIR BAG
Basic MechanismA 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.
Main Components:
1) Airbag module
2) Diagnostic Unit
3) Crash sensors
Airbag ModuleContains 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.
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)
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 dashboardUsually stores electricity to activate airbag in the event that a crash damages the battery / link to battery
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.
Ball tube crash sensor
Airbag Deployment
Frontal crash scenario: Car crashes into an obstacle (wall) at 20+ mphSensors 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
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)
Limitations ?
Airbag fatality statistics
Applications:
Airbag landing system
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.
The Airbag Jacket
These jackets are designed to keep
motorcycle riders safe during a crash, and
typically have anchoring cables and a CO2
cartridge.
The Avalanche Airbag
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.
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.