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The
2003 Mercedes-Benz S-Class sedan is the world's first production
car equipped with an astonishing new system that can sense a possible
collision a few seconds in advance and take pre-crash protective
measures. Called Pre-Safe, this high-tech system inaugurates an
entirely new era in vehicle safety.
Mercedes
engineers concluded that cars can be equipped to sense an imminent
crash up to five full seconds before the actual impact. As a result,
they've designed the innovative Pre-Safe system to first tension
the seatbelts if the system senses an impending collision. The
system uses new resettable electric tensioners in addition to
the existing pyrotechnic belt tensioners that still deploy on
impact. What's more, if the front passenger seat and any of the
electrically adjustable rear seats are reclined, Pre-Safe moves
them to a more vertical position, and, if the vehicle skids (sometimes
a precursor to rollover), the system automatically closes the
sunroof. If a crash is averted, the electric belt tensioners automatically
relax and are ready to deploy again if necessary.
Pre-Safe
reacts to uncorrected fishtailing (or oversteer) as well as "plowing"
(or understeer) by using existing sensors for ESP stability control
that measure steering angle, vehicle yaw and lateral acceleration.
Emergency braking can also trigger Pre-Safe, which monitors sensors
for the Brake Assist system as well.
Mercedes-Benz
accident researchers found that about two-thirds of all accidents
are preceded by skidding, emergency braking or a sudden evasive
maneuver - all of which can provide several valuable seconds of
advance warning before impact. In the past, the auto industry
didn't make use of this relatively wide and potentially lifesaving
"window," since conventional airbags and seat belt tensioners
are only triggered when the impact actually occurs.
However,
Pre-Safe makes use of technology that reads these danger signals
in advance and uses the remaining seconds to react and take some
precautionary measures. In a sense, Pre-Safe equips the car with
reflexes, almost as if it's alive. Just as the perception of sudden
danger triggers a human reflex action, so the innovative safety
technology of the S-Class triggers special systems to reduce the
risk of occupant injury.
In
the future, Pre-Safe could include additional sub-systems such
as extending bumpers, smart crumple zones or moveable interior
door panels designed to help keep occupants further away from
dangerous deformation zones. Radar, infrared or ultrasound technology
could be used to monitor the vehicle's surroundings and measure
the speed, angle and mass of an approaching object. If it's a
truck or van, vehicle height might even be raised to improve crash
compatibility. |
