Mercedes-Benz to Unveil Extraordinary Safety Concept At
Frankfurt
MONTVALE, N.J., Aug. 14 Mercedes-Benz will next month
unveil at the 59th International Automobile Fair in Frankfurt Germany
(September 13-23) the concept for a vehicle that can detect an imminent
collision and engage occupant protection systems before it occurs.
Known as PRE-SAFE(R) (for "Preventive Occupant Safety"), the experimental
Mercedes-Benz safety concept combines hazard-detection technology currently in
use in Mercedes-Benz passenger vehicles with new types of seatbelt tensioners
and automatically adjusting seats. Future versions of the concept would
include active body structure and interior components, as well. Mercedes-Benz
has already developed the sensor systems and actual protective components of
the PRE-SAFE concept to the point that they can be evaluated in test vehicles.
Mercedes-Benz pioneered many of the safety features used in today's
vehicles, including high-performance adaptive airbags, door-mounted side
airbags and side curtain airbags, seatbelt pretensioners and belt force
limiters and crash-optimized body structures. Company safety experts believe
that most of the potential in passive safety technology has now been exploited
and that further advances will require new concepts.
"Interval of Safety"
The PRE-SAFE concept is based on the findings of Mercedes-Benz accident
researchers, which show that in approximately two thirds of all traffic
accidents (as studied in Germany) there is a relatively long time interval
between the driver's recognition of an impending accident and the impact
itself. The researchers believe new technology can activate the vehicle's
protection systems during this interval.
"Our present protection systems such as airbags, side curtain airbags or
belt tensioners must ensure safety in a matter of milliseconds, even though
accident recognition can be measured in seconds," explains Dr. Rodolf
Schoneburg, the head of safety development. "Making use of this interval
opens up new dimensions in occupant protection."
Mercedes-Benz researchers have already been testing a number of
conceivable PRE-SAFE systems, including automatically extending bumpers,
"smart" crash boxes in the front-end structure and even active interior
components such as movable interior door panels, sensor-controlled seats and
other ideas for preventive occupant protection. If the collision is avoided
at the last moment, the PRE-SAFE systems would reset themselves to their
original status, thereby avoiding expensive repairs.
PRE-SAFE Foundation Already In Place Today
Mercedes-Benz researchers believe that the early recognition of an
impending accident and the development of suitable, situation-related occupant
protection technology represent the greatest safety engineering challenge of
the next few years. This innovative technology is based on systems that use
specialized sensors to continuously monitor the driver, vehicle and road
surface and are automatically activated when danger is detected.
Several such systems are already installed as standard in current
Mercedes-Benz models and recognize critical situations at an early stage to
help prevent accidents. The anti-lock braking system (ABS), Brake Assist
(BAS) and the Electronic Stability Program (ESP(R)) driving safety systems
form the basis for the innovative PRE-SAFE concept.
In the field of occupant protection, Mercedes-Benz introduced the concept
of preventive measures more than a decade ago. The outgoing-generation
Mercedes-Benz SL coupe/roadster models, introduced in 1989 (1990 in the US),
came equipped with the world's first automatic-deploying rollover bar, which
deploys in just three-tenths of a second if onboard inclinometer sensors
detect a potential rollover. The current CLK-Class Cabriolet is likewise
equipped with such an anticipatory rollover protection system.
Protection Can Begin Before an Accident Occurs
In a future PRE-SAFE equipped Mercedes vehicle, the new occupant
protection systems would go into action when sensors in the car detect that
the vehicle is on a collision course with another vehicle. Even before the
driver has time to react and apply the brakes, the seatbelts will tension and
restrain the driver's and passengers' torsos, preventing their bodies from
moving forward during the braking maneuver and ensuring a safe seating
position. At the same time, the seat cushions of the front passenger and rear
seats will automatically tilt to the rear, while the door panels will move
into the car's interior and mold themselves around the occupants' hips like
protective shields.
Accident analyses by Mercedes-Benz researchers show that in two thirds of
all collisions, enough time elapses before the impact to activate such
protective systems. In roughly 60 percent of the more than
1,000 reconstructed accidents, the vehicles involved were in a dynamic state
that indicated an impending impact.
"For Mercedes, PRE-SAFE means the logical continuation of our long-held
safety philosophy," says Dr. Schoneburg. "In the future we will also be able
to use the time interval between recognizing a dangerous situation and the
point at which the actual impact occurs to prepare the car for the impending
crash and therefore give the occupants the best possible protection. Our
previous protection concept will therefore be supplemented with an additional
PRE-SAFE phase."
Mercedes-Benz Protection Concept With PRE-SAFE
1 Warning phase Sensors on the axles and bodywork monitor the
vehicle's behavior. When the vehicle's dynamic
limits are reached, a yellow warning symbol
lights up in the cockpit.
2 Assistance Phase Standard dynamic systems such as ABS, Brake
Assist and ESP(R) automatically intervene in
critical situations and help to make these
controllable for the driver.
3 PRE-SAFE phase The sensors detect the enhanced probability of
an accident. Various safety systems are
activated as a precaution to prepare for the
possible accident and prepare both the vehicle
and its occupants. If the accident is avoided,
the PRE-SAFE systems are automatically reset to
their original status.
4 Light impact In the case of impacts up to about 9 mph, the
bumpers and crash boxes in the front-end module
absorb the impact energy. Sensors monitor the
impact severity and prevent activation of the
airbags if their additional protection is not
required.
5 Minor accident During a more serious impact, robust structural
members in the front end, sides and rear end
absorb energy and distribute the forces over a
wide area. The belt tensioners go into action.
Depending on impact severity, the front airbags
inflate less than fully to ensure optimal
occupant protection. Door-mounted airbags and
side curtain airbags provide protection during
a side impact. The automatic front passenger
and BabySmart(R) child safety seat recognition
system prevents activation of the front
passenger airbag and belt tensioner if they are
not required. The fuel supply to the engine is
cut off.
6 Serious accident In the event of even greater risk to the
occupants a second, additional stage is
activated in the front airbags. At the same
time, the belt force limiters are activated.
7 Recovery phase The doors are automatically unlocked after the
accident. The Tele Aid emergency call system
(available on all Mercedes-Benz models) alerts
emergency services and guides them to the scene
of the accident. The hazard warning flasher
system is switched on.
Calculating Accident Severity Before The Collision
The Mercedes-Benz PRE-SAFE system relies on sensors that not only
recognize a critical dynamic situation, but also provide data from which the
computer can predict an accident with a high degree of probability. This
enables the electronics to initiate suitable protective measures even before
the crash. Mercedes-Benz takes a multi-stage approach with this sophisticated
sensor system, which is divided into four sub-systems:
-- Dynamic sensor system: Evaluates the actual vehicle dynamics and
detects critical deviations from the nominal dynamic values. For this
purpose it measures, for example, vehicle speed, braking torque, brake
pedal speed, wheel slip, acceleration around the vertical axis (yaw),
suspension travel, steering speed and tire pressure.
-- Pre-crash sensor system: Monitors the surroundings using, for example,
ultrasonic, infrared or radar technology and image processing to
register the distance from a possible obstacle, its relative speed and
the possible angle of impact. This system provides information
concerning the nature and severity of a possible accident.
-- Crash sensor system: Recognizes an actual impact within a few
milliseconds with the help of acceleration, pressure, intrusion and
contact sensors that can even provide information about the ultimate
severity of the accident.
-- Interior sensor system: Establishes which seats in the vehicle are
occupied, measures the weights of the passengers, monitors the seatbelt
buckles and could in the future also register the exact positions of
the occupants using infra-red signals or image processing.
Matching Crash Compatibility With Larger Vehicles
On the basis of these sensor data, a powerful onboard computer prepares
the vehicle components and vehicle structure for an impending accident. This
involves, for example, extending the bumpers and activating the crash boxes in
the front-end structure. Depending on accident severity, these systems would
generate forces suitable to absorb a large proportion of the impact energy
before it can act on the vehicle occupants.
In the event of an impending side impact with a higher vehicle, such as a
large SUV, van or truck, the computer would engage the Active Body Control
system (currently used on the Mercedes-Benz CL-Class coupes and certain
S-Class sedans) to raise the vehicle body and enhance its crash compatibility
with the colliding vehicle. At the same time, the sunroof is automatically
closed to prevent the occupants from being ejected in the event of a rollover.
Interior: Seats, Steering Wheel and Door Panels Automatically In
Protection Position
In the PRE-SAFE concept, new safety systems in the interior deploy if the
electronics have calculated the high probability of an accident. These
measures ensure that the occupants are placed in the most protected position
possible even before the impact:
-- Automatic seat adjustment lowers the seat cushion to the rear if
required and adjusts the backrest to the best possible position so that
the airbag and seatbelt can function with optimum effect.
-- The belt tensioners are already activated before the impact, preventing
the occupants from moving too far forward during emergency braking or
preventing excessive lateral movements of the torso if the car begins
to skid. Tests carried out by Mercedes engineers show that the
PRE-SAFE belt tensioner is able to reduce forward body movement by up
to 150 millimetres and lateral movement by up to 300 millimetres. This
means that the occupants are in the best possible seating position when
the impact occurs, enabling the airbags to carry out their protective
function to the fullest.
-- A knee protector automatically extends from the instrument panel to
reduce the forces acting on the legs during a frontal impact. It would
also be conceivable to install interior door panels that move towards
the occupants before the crash and keep them away from any body
components that might penetrate into the interior during the accident.
Extending panels on the insides of the B-pillars could provide the same
protective function.
Long-Term Objective: Accident-Free Driving With "Thinking" Systems
Mercedes-Benz has set its safety objectives even higher for the long-term
future. Company engineers are planning a "thinking" car that is able to
recognize its surroundings. This means not only recognizing the road ahead or
other vehicles, but also traffic lights, road signs and pedestrians. In
addition, Mercedes cars of the future will be able to interpret traffic
scenarios and, if necessary, initiate accident prevention measures by
themselves.
