I think you mean an airbag that would absorb the impact energy of the
cars relative to each other. As research_help says, front and side
impact airbags spread the forward or sideways energy of the
passenger's deceleration over a longer period of time relative to the
car they are in. In general the seat and headrest are designed (or
should be) to do this in a rear end collision.
Dissipating the energy of motion of the cars relative to each other
would be a much more challenging task for an airbag. The car frame is
designed to do this to some extent. Similar systems are in place to
abate the severity of rear end collisions on highway repair trucks and
other vehicles. As far as I know, they do not use air bags, but rather
collapsible metal honeycombs that spend energy in plastic deformation
(by bending - like the car's frame), or water or sand filled
compartments that use energy in accelerating the water or sand mass
out of the compartments.
I'm not sure what type or size airbag would be able to dissipate the
energy of an automobile collision. Perhaps the type used to bounce
space capsules to a safe stop... or not.
If you are not talking about dissipating the energy of the cars
relative to each other, but are trying to do a better job than the
current seats of protecting the passengers from rapid
acceleration/deceleration, that is a different story, and again might
be better served by something other than an airbag. But I wouldn't
totally rule out some deflation mechanism to dissipate that energy.
Maybe a pre-inflated bag in the hollow of the seat back. But then you
still have the second part of that movement - when the backward motion
relative to the passenger compartment ceases, and a forward
acceleration relative to same begins - the lash part of whiplash. You
would need to handle that too. Read how Volvo does it:
http://www.autoworld.com/news/volvo/s80_safety.htm
Look for the text "WHIPS seat". |
