- 40 percent cleaner
- 20 percent lighter than competitors
- 13 percent more fuel-efficient
- Optimised torque from 2500rpm
Mercedes-Benz has debuted a striking, new range of all-alloy V6 engines designed to
power its passenger cars into a cleaner, greener 21st Century.
The new V6 engines are cleaner, lighter and more economical than their predecessors, which
had been in production since 1984.
The V6's (the first ever built by Mercedes-Benz) are marginally more powerful than the
former in-line powerplants but produce their maximum torque at lower engine speeds. This
adds up to smoother, quieter driving characteristics.
The first new V6 (of 3.2 litres capacity) features in Mercedes' latest E-class saloons and
the same powerplant will shortly appear in the dynamic, new CLK coupe'.
The new V6 is also smaller than former iron-block, in-line engine - giving designers
greater scope when creating new body shapes and styling cues.
The shorter dimensions of the V6 also contribute to greater safety by further reducing the
risk of mechanical intrusion into the passenger compartment during frontal impacts.
Already dubbed 'The World's Safest Car' the latest E-class, equipped with the new V6, has
the potential to raise automotive safety to new heights.
With the in-line engine configuration now developed to its fullest environmental capacity,
the most efficient answer to future emissions legislation is through the use of the
lighter V-engine design.
The new V6's rank among the world's most environmentally compatible six-cylinder
units. Emissions from the latest Mercedes powerplant are about 50 percent below
the current EU values and the strict American limits for 'low-emission-vehicles'.
Three Valves per Cylinder
To a large extent, this has been possible through the use of three-valve dual
ignition technology by Mercedes for the first time.
Better emissions have been achieved by dispensing with one exhaust valve per cylinder
which reduces exhaust gas heat loss enabling the catalytic converter to reach its optimum
temperature much quicker.
Additionally, dual ignition almost completely burns the fuel-air mixture in the first
instance ensuring that the untreated V6 emissions are already very low, in all operating
modes, before they reach the catalyst.
The combination of dual ignition, lightweight design and low-friction construction help
the new V6 achieve fuel economy figures up to 13 percent lower than the previous
straight-sixes making it one of the world's most efficient six-cylinder petrol
engines.
The all-alloy V6 produces the same 3 1 5 Nm torque as the previous in-line six. But
importantly, the V6 achieves its maximum torque performance lower in the engine revolution
band at 3OOOrpm (against 3850rpm for the in-line six).
And because of the new engine's brawnier torque pattern, around 95 percent of the
engine's available torque is on tap from just 25OOrpm.
The new V6 produces 165Kw power (up from 162kW). 90 Degrees
The new V6 is designed to a 90 degree configuration and uses a balancer shaft in the
crankcase to minimise noise and vibration. The shaft rotates in the opposite direction to
the crankshaft at the same speed compensating for the free vibrations normally found with
V6 engines. The result means the new V6 can match the former straight-six for its
smooth power delivery refinement.
The 90-degree configuration is also more rigid in design and installation producing lower
vibration than similar in-line sixes.
Engineers concentrated on noise reduction in the critical 500-1500 Hertz band - the
frequency which is the most sensitive to the human ear.
Technical data - Mercedes-Benz V6 3.2 litre engine
Capacity 3199cc
Max.Power 165kW (5600rpm
Max. Torque 315Nm (~3000-4800rpm
Cylinder diameter 89.9mm
Cylinder 5 acing I O6mm
Bore 89.9iTun
Stroke 84.0~
Connecting rod length 148.Smm
Crankcase height 221 .9mm
Main bearing diameter 64,Omm
Cold Start
The catalytic converter remains the key automotive emission control component but its
limitations mean it is unlikely to help engines comply with future regulations.
Current engine technology enables the catalyst to reach its optimum operating temperature
inside 90 seconds. Future European and American
regulations will demand a maximum one minute warm-up.
Mercedes' innovative engineers have again pioneered the answer, this time with three-valve
technology.
The new, V6 engines feature two inlet valves and one, large sodium- cooled exhaust valve.
By dispensing with one of the exhaust valves the exhaust port surface is about 30 percent
lower than the four-valve engine and this greatly reduces heat-loss from the exhaust gas
flow by a significant 70 degrees Celsius compared with the four-valve engine.
As a result the catalyst can reach its optimum efficiency, from a cold start, around 12
seconds earlier.
Emissions 40 percent lower
The use of three-valve, dual-spark technology and quicker responding catalysts reduce
emissions from Mercedes new V6 engines by an impressive 40 percent.
Two spark plugs per cylinder mean the V6 is able to bum fuel at practically 100 percent
efficiency. With only one spark plug, this cannot be guaranteed. Unburnt fuel equals
higher emissions - especially during engine warm-up.
More pioneering technology from Mercedes-Benz adds to greater emissions control: a new
process, which makes do without conventional welding seams, was used for construction of
the inner tubes of the exhaust manifold. Instead, the internal components are simply
interlocked and attached to the outer shell with laser welds.
This new technology (called internal high-pressure forming - IHU) has been jointly
developed and patented by Mercedes and Germany's Paderbord University.
Doing away with the welding seams increases the life of the manifold and reduces
its weight.
The catalytic converters for the V6 engines also feature a tri-metal coating made from
rhodium, palladium and platinum which heats up more quickly.
In the Long-Term
The proposed European emission regulations demand that manufacturers document the
performance of their componentry over the long-term:
160,OOOkms. And dual ignition helps here, too.
In case one ignition circuit should fail, a second system ensures an adequate mixture
combustion. Mercedes-Benz is investigating the durability of its exhaust systems in
comprehensive programs which have already clocked more than three million test kilometres
in Germany and the USA.
Fuel Efficient
Dual ignition, exhaust gas recirculation and a host of other intelligent fuel saving
measures result in a hefty 13 percent fuel saving for the new 3.2 litre V6 over its
in-line predecessor. The new, E320 E-class 5-speed automatic uses only 6.8 litres/I O0kms
on the highway.
The Mercedes V6 powerplants are among the most economical engines in their displacement
category worldwide.
E320 Saloon 5-speed automatic
fuel consumption:
I City 110.0 litres/IOOkms I
Highway 6.8 litres/lOOkms
AS 2877 figures
Lightweight
Intelligent use of high-tech materials like magnesium, as well as a greater use of
aluminium, have helped the V6 engines to a trimmer profile over the former in-line sixes.
The 3.2 V6 is around S0kgs lighter than the Mercedes in-line engine it replaces. This also
makes the new powerplant one of the lightest V6 engines in the world
weighing 50kg (25 percent) less than its predecessor and up to 20 percent less than
similar engines produced by competitors.
Weight saving have been made through the introduction of more lightweight metals.
Now made from aluminium are: crankcase (reduced from 55kg to 26 kg), oil sump,
cylinder head, pistons, roller-type rocker arms, engine control unit housing. Made from
magnesium are: intake pipe, cylinder head cover and closing covers. A hollow, single
camshaft per cylinder bank also saves weight.
Torque Spread
But, in addition to ecology and saving weight, driving enjoyment was high on the
priority list for the new V6 range. Before settling on the performance dynamics for the
new engines, a test program analysed the everyday, practical needs of motorists and logged
the engine-speed ranges most commonly used in everyday driving.
The two-year test involved 12 cars covering 400,000 kms and produced data during typical
road trips showing engine speed figures (normally in the 2000 to 5OOOrpm band).
The engineers set up the new, V6 engines for high elasticity and maximum torque available
over wide engine-speed band (3000 - 4800 rpm). This design means drivers can make more use
of fourth or fifth gear and save fuel by operating at lower engine speeds.
New Manufacturing Plant
The new range of V6 engines is manufactured at Mercedes-Benz' newly- built plant at
Bad Canstatt in the suburbs of Stuttgart. Fittingly, the plant now occupies the site of
Gottlieb Daimler's first workshop erected there in
1887.
Built at a cost of \$A615 million, the Bad Canstatt facility is now the world's most modern
engine plant employing 1200 people and producing more than 1600 engines per day.
In building the new plant, Mercedes-Benz placed environmental compatibility high on the
agenda. More than 5,000 sq.m of roof-mounted solar panels produce more than 500kW power
for the factory (equal to the amount of power needed for 120 average homes). And, through
effective treatment of waste, the factory produces no harmful effluent's.
Because of the similarities in production techniques of V6 and V8 engines it is possible
to achieve a number of production advantages at Canstatt, which compensate for the higher
cost of V-engine production.
Although the former in-line engine still has some minor technical and economic potential
Mercedes engineers found that genuine, forward looking innovation could only be achieved
by building a new engine from scratch.
And by constructing a new factory it will be possible to eventually build, under the same
root, six-cylinder and eight-cylinder engines which Mercedes currently manufactures in
different locations.
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