Mercedes-Benz M-Class Gets Top EPA Fuel Economy Among SUVs
20 January 1998
Mercedes-Benz M-Class Gets Top EPA Fuel Economy Among SUVs; Automaker Builds Sport Utility To Meet Passenger Car Standards
MONTVALE, N.J., Jan. 20 -- The new Mercedes-Benz M-Class gets
better gas mileage than any other premium sport utility vehicle, thanks in
large part to its new-generation 2l5-horsepower V6 engine. According to the
U.S. Environmental Protection Agency (EPA), the M-Class tops its market
segment with fuel economy ratings of 17 miles per gallon in the city and 21
mpg on the highway. The premium segment is comprised of all SUVs with a base
price over $28,000.
Mercedes-Benz designed its M-Class sport utility vehicle to be compatible
with the world around us. According to MBNA president Mike Jackson, "The
current two-tiered standards may have made sense back when light trucks were
driven mostly by farmers and craftsmen, but it's clear that these types of
vehicles are now being used primarily for everyday family transportation. For
this reason, we feel that SUVs should offer the same levels of safety and
environmental protection as passenger cars."
M-Class Performs at Ultra-Low-Emission Levels
In a feat many passenger cars have yet to attain, the super-clean M-Class
sport utility is already performing at "Ultra-Low-Emission-Vehicle" (ULEV)
levels. In EPA certification tests, 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).
The chart below (in grams per mile) puts this impressive performance in
perspective with current standards:
HC C0 NOx
M-Class certification 0.032 0.25 0.07
Current Federal standard: cars 0.25 4.4 0.4
trucks 0.32 4.4 0.7
California LEV standard: cars 0.075 3.4 0.2
trucks 0.16 4.4 0.4
California ULEV standard: cars 0.04 1.7 0.2
trucks 0.10 4.4 0.4
The LEV and ULEV emissions standards are being phased in gradually, and
for the 1998 model year, 25 percent of each automaker's sales in California
must be certified to the LEV standard.
New Twin-Plug Engine Technology Means Leaner, Cleaner Engines
In general, 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 per cylinder, and
the dual ignition system activates the twin spark plugs one after the other in
quick succession rather than simultaneously, with electronically varied
"stagger," for cleaner-burning combustion and smoother, stronger performance.
Three-Valve Technology Reduces Emissions by 40 Percent
The new Mercedes-Benz engines use innovative three-valve-per-cylinder
technology to reduce exhaust emissions dramatically -- over 40 percent during
the critical warmup stage when much of engine emissions are produced. There's
less surface area at the exhaust port, relative to a comparable four-valve
engine, which dramatically reduces exhaust between loss between the engine and
the catalytic converter. This translates to higher exhaust temperature and
earlier converter "light-off." In general, there is no tradeoff in horsepower
and torque with the new three-valve technology compared to a four-valve
design. In any efficient, well-designed engine, exhaust valve size needs to
be somewhat smaller than the intake valve area.
Another Mercedes-Benz First - Low-Friction Silicon-Aluminum Cylinder
Sleeves
Mercedes-Benz was the world's first automaker to use innovative cast-in
silicon-aluminum cylinder sleeves with a low-friction surface that allows
piston-ring spring tension to be reduced by 50 percent. Thanks to a number of
such friction-reducing measures, the internal "drag" of the new engine is 45
percent lower than other engines, and the efficiency pay-off for low internal
friction means fuel savings, increased power and longer engine life.
The Longest Intake Runners In The Industry
The new Mercedes-Benz engines also feature the longest intake pipes in the
industry, a plus which provides outstanding low- and mid-range power. Cast
into the super-lightweight magnesium intake manifold are long intake passages
which spiral around to each cylinder. Incorporated into the manifold are
flaps (one for each cylinder) that are closed below about 3,700 rpm, forcing
intake air to take the "long route" through the manifold and build up pressure
waves which boost the intake process and improve low- and mid-range torque.
At higher speeds, the flaps open electronically, allowing intake air to take a
shortcut -- a more direct route to the cylinders for maximum high-speed power
and efficiency.
M-Class Dominates Latest Automotive Awards
In a critical evaluation of both real-world performance and design
excellence, the new-generation 3.2-liter V6 engine from Mercedes-Benz was
recently named one of the "Best Engines of 1998" by Ward's Auto World, the
noted industry trade magazine. In their coverage of the new Mercedes-Benz
engine, Ward's editors said, "This is a solid, technically significant new
engine range." Ward's, which conducts the only competitive evaluation of
automotive powerplants, ran comprehensive tests of 28 different engines over a
two-month period.
In addition to the "Best Engine" accolade, the new M-Class has won many of
this year's top automotive awards. 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