Airbags

Present and Future

Air-bags

• GM was first to mass-produce air-bags in 1974 (Oldmobiles and Cadillacs)

• Basic components are similar in all vehicles

• Sensing devices/sensors could be anywhere

• 8-14 mph impact needed• +/- 30 degrees from frontal impact

Air-bags

• Since 1987, at least 60 million vehicles have factory equipped airbags

• 90% of 1997 cars have airbags• Driver deaths reduced 14%• Passenger deaths reduced 11%• There is a 33% increase in deaths in

children from passenger side bags

Air-bag tips

• Look for larger, rectangular steering wheel hubs

• Always have the battery disconnected• Sodium Azide is toxic, but when it

burns it turns into harmless nitrogen• Powdery residue after deflation is only

corn starch, talcum powder or baking soda

Sequence of Events

• Sensors detect sufficient inertia causing ball or switch to complete ground circuit

• Igniter squib detonates• Squib generates thermal reaction• Thermal reaction ignites Sodium Azide• Sodium Azide releases large quantity of

nitrogen gas• Nitrogen gas inflates the bag• All occurs in 50 milliseconds

Disarming the system

• Disconnect ground cable of battery• Disconnect the yellow squib

connector at the base of the steering wheel

• GM systems and others have a reserve charge

• All systems should be assumed to be able to discharge for the next 5-10 minutes after disarming

Kids & air-bags

• Kids don’t have the weight or height• Car seats smash kids into seat back• Child’s head gets full

impact/hyperextension• Bag inflates at a speed of 200 mph• Most killed by air-bags are small women• Kids should be in rear/center• Consider air-bag when assessing kids

Side impact air-bags

• Found on cars after 1995• Expect more manufacturers to follow• Works similar to front air-bags• Side-impact air-bags WILL deploy if

the sensor is hit or under pressure• To disarm, cut black, ribbed cable

running from sensor unit to air-bag– Found between seat back and seat

bottom

Curtain air-bags

• Covers side windows• Deploy downward in 25 milliseconds• Stay inflated for about three

minutes• Work in conjunction with side air-

bags from seat• Will be found in 1999 vehicles

More !@#$%^&* Airbags

Inflatable Tubular Structure (ITS)

• Attach to posts and roof rails• Has no exhaust ports (may remain

inflated)• Cut out of the way• Deflate (very little pressure)

SmartBelt

• Works with existing vehicle airbags• Expect to see in two years• Inflates within the first 10

milliseconds of a crash– Airbags deploy after 25-30

milliseconds

Air-bag video