Mercedes-Benz Builds M-Class for SUV-To-Car Crash Compatibility; M-Class Sport Utility Designed With Collision 'Kindness' in Mind
5 February 1998
Mercedes-Benz Builds M-Class for SUV-To-Car Crash Compatibility; M-Class Sport Utility Designed With Collision 'Kindness' in Mind
MONTVALE, N.J., Feb. 5 -- The new Mercedes-Benz M-Class sport
utility vehicle is designed to be compatible with passenger cars in
collisions. Unlike SUVs that are based on existing truck platforms, the
Mercedes M-Class features a clean-sheet design which allowed its developers to
take a fresh approach to occupant safety as well as compatibility with other
vehicles.
Mercedes-Benz engineers have already given considerable thought to what
happens when a small car collides with a larger vehicle. While people in the
smaller vehicle are usually at greater risk, thoughtful engineering can help
protect the occupants of both vehicles.
Frame Structures Should Meet Squarely; Crumple Zones Can Be Fine-Tuned
Auto safety experts maintain that two key factors determine crash
compatibility, especially between vehicles of disparate size. First and
foremost, the main structures of the two colliding vehicles must align and
meet squarely, which means that the frame members of both vehicles must be
about the same height above the road. This not only reduces the possibility
of one vehicle overriding the other catastrophically, but also helps the
protective crumple zones designed into both vehicles to serve their purpose in
absorbing crash energy.
Secondly, the crumple zone performance of a larger vehicle should be
"equalized" to a smaller car, since a larger vehicle can safely absorb the
same crash energy and thus help protect the occupants of both vehicles.
Mercedes-Benz designers have been fine-tuning crumple zone stiffness relative
to vehicle size for several years, and this sophisticated new concept is
likely to be adopted by other automakers.
Mercedes-Benz Safety In An SUV For The First Time
To address the first point, the frame rails of the Mercedes-Benz M-Class
are about 19.5 inches above the ground, within an inch in height of typical
passenger cars. In most other sport utility vehicles, this dimension
(measured from the mid-point of the longitudinal frame rails to the ground)
varies from about 21 inches to as high as 28 inches. However, the M-Class
still has 8.5 inches of ground clearance for good off-road performance.
Although the M-Class sport utility uses a body-on-frame design, the
dynamics of its crash protection are roughly equal to the Mercedes-Benz E-
Class luxury sedan which has a highly acclaimed unibody structure. In
addition to a conventional front crumple zone built into the nose of the
vehicle, the M-Class incorporates a special structure in front of the lower
"A" pillars. In a severe frontal offset collision, this extra crumple zone
can actually help absorb additional crash energy, providing even more
protection for the occupants of both vehicles.
M-Class Also Performs at Ultra-Low-Emission Levels
In general, the new M-Class is designed to be compatible with the world
around it, and the super-clean M-Class sport utility is already performing at
"Ultra-Low-Emission-Vehicle" (ULEV) levels, a feat many passenger cars have
yet to attain. Thanks to its new-generation 215-horsepower V6 engine, the new
M-Class sport utility yielded exhaust emissions of only 0.032 grams per mile
of HC (unburnt hydrocarbons), 0.25 gpm of CO (carbon monoxide) and 0.07 gpm of
NOx (oxides of nitrogen) in certification tests conducted by the U.S.
Environmental Protection Agency.
In terms of fuel efficiency, the M-Class is rated higher than any other
premium sport utility vehicle by the EPA. The M-Class tops its market segment
with EPA numbers of 17 miles per gallon in the city and 21 mpg on the highway.
Overall, the new-generation Mercedes-Benz powerplants get up to 40 percent
lower exhaust emissions, 13 percent better fuel-efficiency, are 25 percent
lighter in weight, and have a broader torque range than previous Mercedes
engines. The new engines feature two spark plugs and three valves per
cylinder, for cleaner-burning combustion and smoother, stronger performance.
A Chassis Designed Exclusively For A Sport-Utility Vehicle
Another key part of the M-Class safety story is its independent front and
rear suspension. Many SUVs have only independent front suspension, while some
even use "solid" axles front and rear. Four-wheel independent suspension
gives the M-Class impressive handling, stability and ride comfort, both on and
off-road.
Compared to rigid axles, independent suspension reduces unsprung weight by
two-thirds, resulting in both better handling and ride quality. The M-Class
suspension features upper and lower control arms in a double-wishbone
configuration at the front and rear, with stabilizer bars and double-tube gas
shocks as well.
Even One Wheel Makes It Go
The M-Class employs a sophisticated four-wheel adaptation of the company's
proven electronic traction control system to help maintain stability and
traction under a wide range of road conditions. The M-Class system senses
wheel slip electronically and brakes the slipping wheels, which delivers the
right amount of torque to those tires with the most grip, on virtually any
road surface. Unlike conventional four-wheel-drive systems, the M-Class
system provides mobility even when three wheels lose traction.
Using four-wheel traction control rather than locking differentials aids
maneuverability, both on and off-road. In tight steering situations there is
no axle "binding," which the driver would experience as sluggish steering
response and vibration.
Like every 1998 Mercedes-Benz passenger vehicle, the M-Class is also
equipped with dual front airbags, emergency seatbelt tensioning retractors
(ETRs) and belt force limiters as well as front door-mounted side-impact
airbags.
M-Class Dominates Auto Industry Awards
The new M-Class has won 20 of the top automotive industry awards this
year. Among these, the new M-Class was voted the North American Truck of the
Year by an independent jury of 48 top automotive journalists and was named
Motor Trend's Truck of the Year by their editors.
SOURCE Mercedes-Benz of North America