Ch. 22 Airbag Restraint Systems

Inflation Chemicals Most common chemicals used in front airbags?

1. Sodium Azide 2. Potassium Nitrate

Safety Note Use extra caution when cutting which pillar?

"B" Pillar -Make relief cut below the level of the pretensioner, adjacent to the rocker channel.

How do you very that the battery is disconnected?

-Attempt to turn on lights -Do not attempt to turn on ignition

Inflation Chemicals In a solid state, are these chemicals toxic or not toxic?

-Chemicals are extremely toxic. -Enclosed in metal canister -If does rupture, use gloves and eye pro

Are there standard for airbag placement?

-Driver and pasaanger front airbags. -All other airbag placement is of the makers discussion

Front Impact Airbags What is the speed needed for airbag deployment?

-Equivalent to 8-14mph or greater for frontal collisions -Some deploy at 150-180mph and inflate 2 1/2' across and fill 2.3cu.ft.

Inflation Chemicals How does Temperature Compensated Stored Gas work?

-NO chemical reaction -High-pressure (1400psi) stored gas cylinder with pyrotechnic initiator housing connected to the gas cylinder

Smart Airbag Systems What does it analyze?

-Seat occupancy, occupant weight and position, seatbelt use, point of impact and speed of impact to adjust airbag deployment to provide the best protection

Inflation Chemicals What byproducts are produced during airbag inflation?

-Talcum powder and cornstarch are used to lubricate the bag. -Also small amounts of sodium hydroxide (powdery residue) -Where gloves and eye pro

What will disconnecting the battery do/not do?

-Will reduce, but not illuminate potential for accidental deployment of pyrotechnic system. -discharge can take as long as 30 minutes after being disconnected

Duel Airbag System What would a partial inflation result in?

-first stage deployment, second stage occurs within milliseconds -First stage deployment with no second stage -Leaves potential for for secondary deployment

In what year did it become mandated for vehicle manufacturers to provide front impact airbags?

1997

Inflation Chemicals Temperature Compensated Stored Gas type of gasses?

95% Argon 5% Helium

Head/Thorax type impact bag Seat Mounted bags deploy from where?

A seam in the side of the seat. -Inflate upwards as high as the roof rails

Smart Airbag Systems What happens if occupant is not wearing seatbelt?

Airbag deploys at a lower speed impact

Safety Note Treat pretensioner systems with same caution you would when working around airbags. When would you cut or remove the Seat Belt?

As soon as practical is recommended so there is no accidental activation

Tubular Head Impact Airbags What type of vehicles will these be found?

BMW's -Deploys downward from the "A" pillar and roof rail, creating a rigid diagonal structure

What is the heart of a vehicles electrical system?

Battery -Wet Cell, acid type

Curtain design head impact Airbags Where are the cylinders?

Both sides of the vehicle

Seatbelt Pretensioner How do mechanical activated pretensioners activate?

By pressure or shock. -Stay live even when battery disconnected -Little force to activate

Sensors How do mechanical sensors activate?

By pressure or shock. -Will most likely be located near the airbag they deploy -Pin system, when depressed, small detonation occurs

Where is the battery located?

Can now be found in front wheel well, under rear seat, or in the trunk. -placed here to increase battery longevity along with vibrations found in hood

What should you do prior to disconnecting the battery?

Carefully operate the power seat, door locks, windows, or trunk releases

Inflation Chemicals What was recently introduced in front airbag applications two reduce byproducts or combustion associated with inflation

Cobalt/Copper

Control Module The Control Module typically contains what?

Contains the capacitors and pastor sensor for the supplemental restraint system

Sensors Remote sensors are used to send signals to where in a cash?

Control Module

Control Module Where can it be located?

Does not have specific location, found in variety of locations.

Head/Thorax type impact bag What is the alternative location for side impact bag?

Door Mounted -best removed from the hinge side -avoid spreading, pinching or cutting

Seatbelt Pretensioner How do electronically activated pretensioners activate?

Electric signal from a remote sensor

Curtain design head impact Airbags What area does it cover?

From the front "A" pillar to the rear pillar. -Deploys downward from roof rail 14"

Smart Airbag Systems What cars use this system?

High end vehicles, only a few used.

Inflation Chemicals How does the Azide work?

Ignited upon sensor contact and converts to nitrogen gas to inflate the airbag -No detectible amount of sodium azide will be present

Head/Thorax type impact bag Where are the sensors located?

In the door, outward side of the seat, near the "B" pillar/rocker channel area

Sensors How do electronically activated sensors activate?

May be remotely located from the bag they deploy and send and change in inertia or rear to negative g force or backward movement

Seatbelt Pretensioner What are the 2 ways they are activated?

Mechanically or Electronically

Sensors Can be activated in 2 different ways

Mechanically or electronically

Tubular Head Impact Airbags How long will it hold inflation?

Minimum of 6 seconds but normally remain inflated for up to several minutes

Front Impact Airbags Where is the drivers side front impact airbag located?

Mounted in the steering wheel hub concealed beneath the vinyl covering

Front Impact Airbags Where are the sensors located for the front impede airbags?

Mounted near the front fenders, under the dash, and under the drivers seat

System can either be negative or positive ground system. What is used primarily in the US?

Negative

Turn off all electrical units and the ignition. Carefully disconnect the ___ cable, then the ___ cable.

Negative 1st Positive

Duel Airbag System New or old technology?

New development, use of inflators with 2 deployment levers

Inflation Chemicals Most common chemical used in side impact airbags/seat belt pretensioner?

Nitrocellulose

Tubular Head Impact Airbags Will roof removal cause deployment?

No, but the open end of the "A" pillar should be considered a hot zone

Aftermarket cars along with diesel vehicles have 2 batteries. Will disconnecting the main battery suffice and protect the rescuers?

No, second battery also needs to be disconnected to ensure no power.

Duel Airbag System Designed to adjust the force of inflation based on what?

Occupants position, crash severity, and seat belt usage

Smart Airbag Systems What happens is seat is unoccupied or too close?

Prevents deployment

Seatbelt Pretensioner Most cars are equipped with what?

Pyrotechnically activated pretensioners -Take up seatbelt slack during impact just before airbag deployment

Pretensioner Location Inner front seat belt buckle area

See photo

Pretensioner Location Lower "B" Pillar

See photo

Pretensioner Location Mid "B" Pillar

See photo

Inflation Chemicals Name of the compressed gas or argon inflators?

Temperature Compensated Stored Gas -Found mostly on curtain design head impact airbags and some front and side airbags

What does it mean if you have a SRS warning light on the dashboard?

There is a fault in the system and an accidental deployment may occur

Front Impact Airbags Following inflammation, gas in the bag is released almost immediately where?

Through vents located on the bottom inner portion of the bags or the steering column

Curtain design head impact Airbags Where is the inflator attached?

To the rearward end of the curtain, in either the "C" or "D" pillar or roof rail of station wagons

Capacitors Designed as a backup power supply if battery is destroyed in crash. How long does it hold a back-up charge for?

Up top 30 minutes

Safety Note Where to cut on mid "B" pillar for roof removal?

Use inverted V, cutting up into the roof rails

Safety Note Inner front seatbelt Buckle. When do you remove?

Usually out of common extrication path, cut or remove seatbelt as soon as practice.

Seatbelt Pretensioner How are they mounted?

With hardened steel brackets

After disconnecting the battery, can static electricity still trigger a deployment?

Yes

Airbag Components Do most vehicles contain similar components?

Yes, smilier components but different locations depending on manufacturer