(from Mercedes-Benz Press Release) Performance, luxury, refinement -- just
three of the outstanding characteristics of the new SL 600 which will
complete the successful Mercedes-Benz SL-Class Roadster model range from
spring 2003.
A look under the bonnet reveals a technological tour de force in the
shape of the newly developed Mercedes twelve-cylinder engine. Equipped
with two turbochargers, an air/water intercooler, three valves per
cylinder, twin-spark AC ignition and other high-tech innovations, the
new unit is one of the most advanced car engines in the world. And one
of the most powerful in its class, too: the V12 engine has an output of
368 kW/500 hp and maximum torque of 800 newton metres, which is
available from just 1800 rpm and remains on tap at a constant level all
the way up to 3600 rpm.
With figures like these, it is clear that the SL 600 has ample resources
to cope with every driving situation. It accelerates from 0 to 100 km/h
in only 4.7 seconds and polishes off the 60 to 120 km/h sprint in 4.9
seconds. The maximum speed is electronically limited to 250 km/h.
The twelve-cylinder unit combines its impressive performance with
exemplary smoothness and extremely quiet operation -- ideal conditions
for a refined, highly enjoyable driving experience.
Standard equipment: COMAND, CD changer and sound system
The theme of refinement and enjoyment is also picked up by the
exceptionally high level of standard equipment in the new
top-of-the-range SL-Class Roadster. Based on the features found in the
already luxurious SL 500, it includes interior appointments such as
ruffled leather, embossed V12 emblems on the head restraints,
soft-texture floor mats with chrome-coloured lettering as well as an
elegant wood/leather steering wheel and a wood/leather automatic
transmission selector lever. The COMAND system, a CD changer and a sound
system are also standard equipment in the new twelve-cylinder sports car
from Mercedes-Benz.
The external cues which identify the SL 600 comprise a radiator grille
with discreet chrome elements, silver-painted brake callipers, V12
emblems on the side air intakes and bi-xenon headlamps. The light-alloy
wheels which are fitted as standard are distinguished by their exclusive
rim design. At the front, the sports car is equipped with 255/40 R 18
tyres, while the rear wheels have 285/35 R 18 tyres.
Parking and manoeuvring is made more convenient by the PARKTRONIC system
which also forms part of the standard equipment. Superb high-tech
systems, such as Active Body Control (ABC), Sensotronic Brake Control
(SBC™) (a new type of electrohydraulic brake system), the automatic
climate control system which is equipped with advanced sensors, and the
innovative vario roof add the perfect finishing touches to the driving
experience and also reflect the special position which the SL 600
occupies among the sports cars in its class.
In addition to the new V12 model, SL-Class customers have a choice of
three other engine versions: the six-cylinder SL 350 sports car with 180
kW/245 hp, the SL 500 with a 225 kW/306 hp V8 engine and the SL 55 AMG
which develops
368 kW/500 hp.
V12 engine: state-of-the-art lightweight power plant features aluminium,
steel and magnesium components
The newly developed twelve-cylinder engine of the SL 600 reflects the
wealth of experience and expertise which Mercedes-Benz brings to the
development of high-tech power plants. The Stuttgart-based automaker is
the world's largest manufacturer of V12 engines for passenger cars.
Diecast aluminium is used for the crankcase of the twelve-cylinder
engine while the two cylinder-head covers are made from diecast
magnesium. Fracture-split conrods made from high-strength forged-steel
alloy, pistons made from a high-quality aluminium alloy, hollow
camshafts of induction-hardened forged steel, a weight-optimised
forged-steel crankshaft and a diecast aluminium sump feature among the
other lightweight components of the engine which weighs just 263
kilograms and has a power-to-weight ratio of 0.71 kg/kW.
This exemplary lightweight design is complemented by the engine's
equally impressive credentials with regard to its noise emissions and
vibration characteristics. These qualities are inherent in the design of
the new V12 unit: the V-angle of 60 degrees balances inertia forces and
moments at source, without the need for special balancer shafts.
Cylinder head: rapid warm-up of catalytic converters thanks to
three-valve technology
A camshaft in each of the two banks of cylinders controls the three
valves per cylinder via low-friction roller-type cam followers. Each
valve has a cam follower and is adjusted hydraulically.
The three-valve technology reduces thermal losses at the exhaust stage
and speeds catalytic converter warm-up after a cold start. In
conjunction with two large ceramic catalytic converters positioned close
to the engine this has a decisive influence on ensuring that the new V12
reliably complies with the strict EU-4 limits. Emissions are controlled
by two catalytic converters which are arranged close to the engine and
which contain two ceramic monoliths each.
Turbochargers: bi-turbo system with two water-cooled intercoolers
The space-saving positioning of the twin turbocharger turbines in the
exhaust manifold maximises their efficiency. A wastegate control system
enables the flow of exhaust gases to the turbines to be matched to the
current operating point of the engine. Wastegate valves are integrated
into each turbocharger and operate electropneumatically, receiving their
commands from the engine control unit.
The compressed air flows through two engine-mounted water-cooled
intercoolers located on the cylinder head covers. Depending on the
engine load the air is cooled here by up to 100 degrees Celsius, so that
its temperature and density are optimised for the combustion process.
The water-intercoolers are integrated in a special low-temperature
circuit. A demand-controlled, electric circulation pump transfers the
heat between the water-intercoolers and the low-temperature cooler
located in front of the engine which passes the heat from the water to
the cooling air.
Ignition: AC system with constant ionic current measurement
A powerful microprocessor controls all the engine functions, making use
of various additional sensor data to control the two turbochargers:
• Pressure and temperature sensors in the charge air distributor are
used to calculate the intake air mass.
• A sensor in front of the throttle valve actuator registers the charge
pressure.
• Sensors upstream and downstream of the air filter monitor the pressure
on the clean air side so that the speed of the turbochargers can always
be adjusted to suit the situation.
In addition, the engine computer controls an advanced
alternating-current twin-spark ignition system whose outstanding feature
is constant ionic current measurement at the spark plugs. This
recognises any misfires and therefore has a major role in protecting the
catalytic converters -- should the ionic current fall below a certain
value the fuel injection for the cylinder concerned is automatically
interrupted at once. Ionic current measurement is supplemented with
torsional vibration analysis at the crankshaft. The combination of both
control signals in this way not only results in an unprecedented degree
of accuracy in the detection of misfires, but also does so across the
entire load and speed range of a twelve-cylinder engine for the very
first time.
