Chevrolet Beat diesel Owner's Manual page 42

38 Seats and Restraints
This crash severity level at which the air
bag will deploy was selected to assure
inflation of air bags in our vehicles at or
below the crash severity at which a
statistical risk of death begins for
frontal collisions.
In the real world, cars rarely crash
squarely into immovable walls; air bags
most often deploy when a vehicle
collides with another vehicle. The
actual speed at which the air bags will
inflate may be higher in the real world,
because real-world accidents usually
involve more complicated multi-
vehicle impacts, angled impacts, and
incomplete frontal impacts (e.g.
sideswipes), and because the object
struck is usually not immovable.
Note
An air bag can also inflate in
moderate to severe non-collision
situations (e.g., slamming the
undercarriage or other solid
component of the vehicle in a dip in
the driving surface) where the crash
sensors generate a signal equivalent
to a crash into a solid immovable
barrier at 15 to 23 km/h (9.3 ~ 14.3
mph).
Air bags inflate when a sensor detects a
front-end crash of a severity sufficient
for air bag deployment. The crash
sensor sends an electric signal to initiate
the air bag's inflation. A propellant is
ignited which rapidly burns inside the
air bag module, producing enough
nitrogen gas to fully inflate the air bag.
The chemical process and nitrogen gas
are harmless to the vehicle's occupants.
Within 0.045 seconds of the crash
detection, the pressure of the inflating
air bag splits open the plastic trim
covering on the module, which is stored
on the inside surface to allow the trim of
the steering wheel hub or passenger-
side instrument panel to split open
under force.
The air bag fully inflates to create a
surface that can catch the forward
movement of the front occupant's head
and upper torso. As the occupant comes
into contact with the air bag, the gas in
the bag empties through holes at the
base of the bag to soak up the force from
the occupant's forward movement.
Note
Air bags cannot smother you and
they don't restrict your movement.
Air bags have vents, so they deflate
immediately after cushioning you.
The entire process, from initial contact
through the air bag's inflation and
deflation, occurs within 0.2 seconds,
faster than the blink of an eye. Because
the collision is over in a fraction of a
second, and vehicles involved in an
accident usually come to the final point
of rest only one or two seconds after
initial contact, the supplemental
restraint system must sense the crash
and cause the air bags to deploy nearly
instantaneously to protect the vehicle's
occupants.
Warning
The best protection can be provided
only when the seat is in a proper
position.
No obstacles are allowed within the
inflation area of airbag.
Wear the seat belt correctly so that
the air bag can provide protection.