For 60 years the
two letters "SL" have had a mystical resonance among automotive
enthusiasts. They stand for powerful sportiness, exciting design,
effortlessly superior style, technical innovations and the ultimate in
engineering artistry. The
Mercedes-Benz SL-Class
inherited these genes from its forefather, designed as a racing car. In
1952 it came to the international race tracks, saw and conquered. It
was from this car that Mercedes-Benz derived the first series-production
model in 1954, the legendary
300 SL gullwing.
And ever since, Mercedes-Benz has been setting the bar high in the
luxury sports car segment with the SL over five model generations.
The
unique combination of systematic sportiness, refined luxury and yet
unrestricted suitability for everyday use at the same time is what makes
the Mercedes-Benz SL-Class the dream car it is - and it is also what
lies behind its success where sales are concerned. The SL was always
ahead of its time technically - even when it was rolling off the
production line for 18 years at a time, as was the case with the SL
bearing the internal code
R107
(from 1971 to 1989). Over 650,000 SL vehicles have left the production
halls in Sindelfingen and Bremen since 1954, and from the last model
generation alone - which celebrated its premiere in 2001 - nearly
170,000 specimens found their way into the hearts of the enthusiasts
amongst fans of high-calibre sports cars.
The new generation of the Mercedes-Benz SL-Class now being presented
is the sixth to follow the 1952 racing car. In the unique tradition of
the SL it is entering its era as an athlete, refined aesthete and
innovative trendsetter with an extraordinarily high utility value.
Mercedes-Benz is initially offering the new SL with two engines - as the
SL350 with a V6 engine and as the SL500 with a V8. The new BlueDIRECT
engines have an output of 225 kW (306 hp) in the SL350 and 320 kW (435
hp) in the SL500 (a 12-percent increase over the predecessor).
Moreover,
the new Mercedes-Benz SL-Class breathes new life into the meaning of
the famous abbreviation "SL" - super-light - through systematic weight
reduction. For the first time ever, Mercedes-Benz is implementing an
all-aluminium bodyshell in series production. The newly developed
vehicle weights approximately 110 kilograms less than a comparable
bodyshell made of sheet steel. Nevertheless it is even more rigid - and
safer - than its
predecessor.
Mercedes-Benz has achieved this through a systematic intelligent
material mix of aluminium alloys and aluminium components which are
tailor-made for the respective requirements, combined with just a few
portions of high-strength steel and magnesium.
Although the new SL
is even more comfortable and has more safety devices on board than its
predecessor and therefore does actually sacrifice some of the weight
saved through the aluminium bodyshell, the scales show some astonishing
figures: the new SL500 (1785 kg) weighs around 125 kilograms less than
its predecessor. On balance, the SL350 (1685 kg) is even 140 kilograms
lighter - all thanks to a host of other intelligent enhanced details to
reduce weight, which Mercedes-Benz has also implemented in the new SL in
addition to the aluminium bodyshell.
And these measurement
results do not just impress as figures on the page; they are very much
perceptible and tangible in practice, too. The resulting increase in
longitudinal and lateral dynamics facilitates superb performance with a
decided passion for cornering. The greater track width at both the front
(+ 38 mm) and rear (+ 77 mm) axle serves the handling which is at once
sporty and agile and keeps the car under safe control. Drivers will find
the new Mercedes-Benz SL-Class even more agile than its predecessor -
sheer pleasure for those of a sporty orientation.
There are two
suspension variants from which to choose. The SL is supplied as standard
with semi-active adjustable damping (lowered by ten millimetres in the
AMG sports package). The active suspension system ABC (Active Body
Control) is available as an optional extra. Unique the world over, it
has been enhanced especially for the new SL.
In keeping with the
Mercedes-Benz tradition, the new SL couples its sharpened athletic
profile and agile nimbleness with a luxurious ambience. Its high-quality
equipment and appointments contribute to the exquisite motoring
pleasure that can be experienced every kilometre of the way. Fine
materials, finished with great attention to detail, shape its style and
character. The levels of comfort here - unique in the segment of luxury
sports cars - blend with high everyday practicality, for the new SL
shines with top marks where open-top motoring, suspension comfort and
comfort on long journeys are
concerned - plus its exemplarily low
background noise, which is comparable with that of a saloon. This all
adds up to the fact that this vehicle is a Gran Turismo in the very best
sense of the word.
The safest and the most sparing
Thanks
to the crash-optimised aluminium structure, standard-fit PRE-SAFE® and
assistance systems on the same high level as the S-Class, the SL is the
world's safest roadster.
What's more, it is the most frugal one in
its class. The SL350 consumes 6.9 litres over 100 kilometres, which is
virtually 30 percent less than its predecessor (CO2 159 g/km). The
SL500, too, posts a persuasive set of efficiency figures: 9.1 litres per
100 kilometres (minus 22%) correspond to 212g/km CO2.
The design,
meanwhile, displays all the classic proportions so characteristic of
the SL. Right from the first glance the masculine-looking roadster with a
broad tail end is immediately identifiable as a member of the current
family of sports cars from Mercedes-Benz. It emphasises its autonomy
through a multitude of details created with loving care.
The sixth
generation of the Mercedes-Benz SL-Class also offers a vario-roof that
can be retracted into the boot using an electrohydraulic mechanism to
save space, converting the SL into a roadster or a coupé, depending on
the driver's wishes and the weather. Unlike its predecessor, three
versions are available for the new SL: painted, with a glass roof or
with the unique panoramic vario-roof featuring MAGIC SKY CONTROL. The
transparent roof switches to light or dark at the push of a button. When
light it is virtually transparent, offering an open-air experience even
in cold weather. In its dark state the roof provides welcome shade and
prevents the interior from heating up in bright sunlight.
With two innovations, the new SL remains true to its tradition as technological trendsetter:
- MAGIC
VISION CONTROL is a new intelligent, high-efficiency windscreen
wiper/washer system. Its system of channels supplies water to the
windscreen just in front of the laser-cut wiper blade lip. As a result,
when spraying, there are no gushes of water on the windscreen to disrupt
visibility, and yet the windscreen is kept clean.
- Also unique,
the Frontbass system uses the free spaces in the aluminium structures in
front of the footwell for housing the bass loudspeakers. As a result,
the new SL features clear, crisp bass sounds that facilitate a concert
hall ambience even with the top down.
Both innovations are part of the extensive standard equipment of the new SL.
Design: Masculine, muscular athlete's physique
The
design of every Mercedes-Benz SL has an obligation to a great legend,
and yet it is always very clearly looking to the future. The designers
have unmistakably showcased the youngest generation of the
style-defining roadster on the basis of tradition, but also with new
perspectives and visions. This has resulted in a formal identity and the
high overall aesthetic quality.
In the interplay between
innovation and tradition we have created a stylish, sporty and elegant
luxury sports car with the classic, well-balanced hallmark SL
proportions: the long bonnet is followed by a compact, set-back
passenger compartment. A broad, muscular, racy-looking tail end
completes the picture.
Design boss Professor Gorden Wagener: "The
athletic, sports star's physique with its masculine, muscular character
says a great deal about the new SL and confidently emphasises its status
as the high-performance heart of our brand. At the same time,
discerning athletic standards are met by powerfully sculpted surfaces
formed by just a few lines and beautifully crafted details. The
traditional design elements from our rich history are more than visual
quotations. They tell of the courage and the pioneering spirit which
have shaped our brand, and reflect these properties in a contemporary
way - with enthusiasm and passion. Alongside top technical performance
and innovations, it is also this which makes the new SL an unmistakable
character."
The front signals a self-confident presence
Visually,
the new SL is clearly marked out as a prestigious member of the current
Mercedes-Benz sports car family. At first glance this is evident from
the very upright classic sports car radiator grille which has featured
on all the Mercedes-Benz vehicles with a sporty character - right from
the initial generation of the SL. The central star in the radiator
grille points the way to the future: it is a contemporary
reinterpretation of the famous trademark, which now runs into the
centrepiece with organically flowing contours.
What's more, on the new roadster the designers have waived the classic
separation
of the bumper and the radiator grille. The lower edge of the grille now
dips into the bumper, supporting the pronounced V-shape and resulting
in more formal presence. In addition to this, the steeply positioned
radiator grille lengthens the bonnet in visual terms. Two air outlet
grilles, each with two chromed fins, have their roots in Mercedes-Benz's
traditional, dynamic design repertoire. A succinctly sculptured edge -
developing from the upright radiator grille - draws across the long
bonnet in a taut arch and flows organically into the A-pillar.
Dynamically
positioned at an angle, headlamps located far on the outside flank the
distinctive front and the broad air intake, giving the new roadster its
own inimitable look. It appears masculine and it does also radiate a
certain restrained aggressiveness.
The standard-specification ILS
headlamps are characterised by very high-quality tubes for the low and
main beam which have been styled with great attention to detail, plus a
chrome bracket surrounding the main headlamp and the flared arrangement
of the indicator lamps and sidelights. All the further functions feature
LED technology - such as the distinctively curved sidelights and the
horizontal band of the daytime running lamps in the outer sections of
the bumper.
The silhouette displays muscles with character
A
minimal amount of artistically styled lines define the athletic yet
smooth surfaces of the flanks. The shoulderline rises from the headlamps
and stretches like a tensed muscle over the entire length of the
vehicle and into the tail lights. Side grilles with fins in the front
wings stylishly cite the classic SL legend and form the starting point
for a feature line. This structures the proportions and lends the
vehicle a visual forwards thrust even at a standstill. It tapers out in
the tail light as a discreet line.
Free-standing exterior mirrors
located on the beltline not only support the modern character of the
side view; thanks to this position they also improve vision of the road.
Depending
on the engine variant, various light-alloy wheels are available in
17-inch and 18-inch versions. The exquisitely bordered wheel arches are
designed for a maximum size of 19 inches at the front and 20 inches
(only in the case of AMG) at the rear.
Muscular tail end
A
small number of sweeping lines shape the broad, clearly defined tail
end. Elegantly flowing and at the same time racy and muscular, it forms
the roadster's distinguished finishing flourish that is so full of
character. Thanks to the boot lid with its steel interior and plastic
panelling, it has been possible to stow the aerials out of sight inside
the vehicle so that they do not interrupt the flowing lines in the rear
area. This is also the case with the roll-over protection, which lies
hidden from view in the body and is only activated in case of danger.
Tail
lights with LED High Performance technology highlight the width of the
tail end. They taper inwards to a point and have a discreet kink in the
contour. The rear fog lamp is located centrally between two trapezoidal
exhaust tailpipes. A horizontal swage line in the lower area of the
bumper provides added emphasis of the broad effect.
The colour
range for the exterior encompasses twelve different paints. These
include the BRIGHT paint diamond white and the special colour cerussite
grey metallic SHAPE - the first matt paint in the standard-specification
paint range for a Mercedes-Benz model series.
Interior and appointments: Luxurious comfort and sporty precision
The
interior of the new SL impresses with its generous amount of space,
high-quality materials, high sense of perceived value and lovingly
crafted details displaying tangible and visible precision.
Compared
with its predecessor, the new generation of the SL is much longer (+ 50
mm to 4612 mm) and wider (+ 57 mm to 1877 mm), providing more room for
more comfort in the interior, too. Shoulder room (+ 37 mm) and elbow
room (+ 28 mm) have been increased, exceeding the dimensions normally
found in this vehicle class. Clear lines create a formally coherent
internal space within this comfortable interior. Perfectly in tune with
the roadster's character, it combines the unpretentious atmosphere of a
high-performance sports car with the comfortable, stylish ambience you
come to expect in a luxurious touring car.
The wrap-around effect has class
In
conjunction with the beltlines on the doors and the parcel shelf, the
upper section of the dashboard creates a formal unity and - with the
exception of the black interior - it is always styled in a contrasting
colour. Generously used wood trim extends from the centre console across
the dashboard into the doors, creating a pleasant wrap-around effect.
Three types of wood along with two different aluminium trim finishes are
available (high-gloss brown walnut, satin-finish light brown poplar,
high-gloss black ash), plus two differently treated longitudinal-grain
aluminium trim parts (light or dark). The links between the dashboard,
centre console and door trim panels have been styled so that they are
continuous and they support the wrap-around effect. Minimal gap
dimensions please the eye and represent the high precision with which
the SL is manufactured.
High-quality instruments add emotionally appealing flourishes
In
the area of the dashboard, four circular ventilation outlets provide
some striking eye-catching touches. Set in metal, these air vents are
reminiscent of jet engines and are a contemporary, emotively interpreted
way of paying homage to the history of Mercedes-Benz sports cars.
Inside
two tubes the sporty instrument cluster boasts classic round dials with
three-dimensional graduated rings, back-lit dials in the centre of the
tachograph and rev counter, plus high-quality needles. In the centre
between the two round dials, a colour display provides information from
the on-board computer and indicates vehicle functions. The system is
operated via a three-spoke sports steering wheel with shift paddles and
twelve function buttons. The steering wheel featuring a flattened bottom
section has an ergonomic grip area and galvanised spokes, and is
covered with nappa leather - in the airbag section, too.
A large
COMAND colour display in the centre of the vehicle takes care of the
numerous display functions for the entertainment, communication and
navigation facilities. A particularly eye-catching feature on the tunnel
of the centre console is a new DIRECT SELECT shift lever. Small and
fine, it is a true visual highlight. Like the central rotary knob for
operating the COMAND system, it is optimally positioned from an
ergonomic point of view. Located in front of these controls is the
lidded compartment for the two cup holders.
Spotlight on the stylish ambience
Making
dynamism visible is what it's all about where the ambient lighting in
the SL is concerned. The fibre-optic cables with three colour options to
choose from stretch between the beltline and the door centre panel in
one tier over virtually the entire length of the door, behind the trim
on the dashboard and in the front panelling.
Seats with a noble, sporty character
The
new Mercedes-Benz SL-Class's fully electric seats with a memory
function meet discerning and wide-ranging standards regarding seating
comfort, ergonomics, safety and sportiness. The ergonomically optimised
seats themselves are more slender than in the predecessor and emphasise
the noble, sporty character. This is underlined in visual terms by
sophisticated stitched seams and by a layout which varies depending on
the choice of leather. Alongside excellent lateral support, the seats
also offer high levels of comfort.
The superstructure of the seat
cushion and backrest is formed by a weight-optimised welded construction
of steel and sheet metal panel parts. This structure also makes a
significant contribution towards transverse support for the sidewall in
the event of a lateral collision. In addition, a thorax-sidebag is
installed in the backrest. A newly developed combination of a sine
spring core principle with rubberised matting and a foam layer as
damping ensures support and comfort.
Both the driver and the
passenger can adjust their seats precisely according to their
requirements and body measurements. Even in the standard equipment there
are extensive electrical adjustment options available for doing so,
enabling fore-and-aft and height adjustment to be made just as easily as
the seat cushion angle, cushion depth and backrest angle adjustment.
The crash-responsive head restraints are also adjustable for height. The
range of equipment also includes 4-way lumbar support adjustment - this
feature is housed in the centre section of the backrest cover. The
occupants can operate it via the central control panel and the head
unit. Using the memory buttons, the current seat position can be stored,
and on the driver's side this also applies to the positions of the
steering wheel and exterior mirror.
A very attractive solution has
been found for convenient access to the rear compartment for easy
loading - in both visual and functional terms. A button on the shoulder
of the backrest operates the backrest lock electrically and enables the
seats to be moved forwards and backwards in order to create sufficient
room to manoeuvre.
Also part of the standard specification is a
seat occupancy sensor with automatic child seat recognition on the
front-passenger side - for child seats with a transponder specially
approved for Mercedes-Benz.
For enhancing comfort even further, in
the case of the leather appointments the seats are covered with
sun-reflecting leather. This specially coated leather reflects the heat
of the sun and, in particular where the appointments colours are dark,
it reduces the extent to which the surface heats up. In combination with
the optional active ventilation the thermal seat comfort is tangibly
improved.
The following seat variants can be selected as an optional extra:
- Luxury
heated seats with active seat ventilation: it ensures a pleasant
seating climate. Leather appointments are a prerequisite for this option
- Active
multicontour seat package: three air chambers in the lumbar area can
vary the contour of the seats in order to prevent fatigue. Elongated air
chambers in both of the side cushions on the backrest ensure optimum
lateral support
- Dynamic multicontour seat: the dynamic
multicontour seat is an enhanced version of the multicontour seat. It
automatically adjusts the lateral structure of the backrest in
accordance with the current driving situation. In order to do this it
varies the air pressure in the seat bolsters on the backrest
electropneumatically, depending on the steering angle, lateral
acceleration and speed
Health and comfort-conscious climate
The
control panel for the standard-specification luxury automatic climate
control THERMOTRONIC featuring separate temperature adjustment for the
driver and passenger has been redesigned and revised. Mercedes-Benz has
placed particular emphasis on new technologies for saving energy. They
include a window demisting sensor integrated in the base of the interior
mirror. It measures the window temperature and interior humidity and
transmits these data to the climate electronics. They can use them to
determine whether the windscreen has misted up. If this is not the case,
in A/C operation it can continuously adjust the compressor in the
background if no dehumidification is necessary. In other words: thanks
to the sensor, the compressor can be operated as required, saving drive
energy. The A/C function can remain permanently active. A further
advantage is that, as the air conditioning only dehumidifies and cools
as much air as necessary, dry eyes are prevented - a tangible gain in
terms of comfort.
The air conditioning is also linked to the ECO
start/stop function and can therefore also regulate the climate during
the stop phases.
So that SL drivers can enjoy an open-air
experience even when the weather is cool, the innovative neck-level
heating system AIRSCARF is available as an optional extra - as was the
case with the predecessor. Warm air flows through a nozzle at the front
of the head restraints, and the system directs it around the head and
neck area of the occupants.
Room for luggage and lots of equipment
Suitability
for everyday use is a key word which is traditionally taken extremely
seriously at Mercedes-Benz - even in the case of vehicles designed to be
very sporty. This is why the occupants in the new SL will find plenty
of stowage facilities for larger and smaller items alike. In addition to
the glove compartment, the centre console offers three stowage
compartments within easy reach:
- One of these is at the front
beneath the air-conditioning control panel, which can be optionally
fitted with two cup holders or with an ashtray and one cup holder
- A large stowage compartment beneath the armrest can be used for the safe storage of a telephone, iPod ® or similar, for example
- A
centrally located rear box with a retractable luggage cover completes
the range. A bottle holder is fitted here as part of the standard
specification, whilst a fire extinguisher is available as an optional
extra
A lockable rear box behind the driver's seat creates
additional stowage space. Its catch is automatically closed when the
vehicle is locked.
In the lower section of the door trim, a long,
open door pocket offers further, easily accessible stowage space. As no
bass loudspeakers have to be fitted in the door thanks to the Frontbass
system, Mercedes-Benz makes sensible use of the space gained here by
adding an extra stowage compartment, which can be used for an umbrella,
for instance.
The designers have also thought the details through:
smaller but useful items can be fixed in place by a net on the centre
tunnel of the passenger's footwell.
The design of the boot is
largely determined by the vario-roof, which has to be housed in the
upper part of the boot when the roof is open. In total the new SL offers
luggage capacity of up to 504 litres - 364 litres with the roof stowed.
There is always room for stowing luggage or two golf bags without any
problems at all, thanks to the optimised boot design.
A luggage
cover which can be adjusted lengthwise with a handle prevents pieces of
luggage from colliding with roof elements in the boot when opening the
roof. Only when the cover is adjusted to the rear can the vario-roof be
opened. Anyone wanting to use the entire boot capacity when the roof is
closed can adjust the cover to the front or remove it completely.
At
the press of a button, the roof elements stowed in the boot can be
tilted upwards by about 25 degrees to make loading and unloading easier -
as was the case in the predecessor (Easy-Pack system).
The
compressor and the TIREFIT filler bottle are housed in a stowage
compartment in front of the recess which can be accessed by lifting up
the boot floor.
HANDS-FREE ACCESS - 'kick' to open
One
of the new products and features from Mercedes-Benz is a system known
as HANDS-FREE ACCESS, which is included in the KEYLESS-GO package. It is
available on request for the new SL for the first time anywhere in the
world, and it allows drivers to operate the boot lid without using their
hands. This work is taken care of by a hydraulic drive system, for
which the control signals are given by the SL owner without touching
anything, but by making as though to kick the area of the rear bumper
with their foot; doing so activates this fully automatic
comfort-increasing equipment. Mercedes-Benz is the only manufacturer to
offer a system which not only opens but also closes the boot lid
automatically.
With the innovative convenience function HANDS-FREE
ACCESS there is no longer any need for drivers to have to get annoyed
by having to put their purchases and other objects down on the - often
dirty - ground when out shopping and when they literally have their
hands full, in order to reach for the handle. Should an unintentional
'kick' result in the boot lid opening or closing without the driver
wanting this to happen, a second kick will correct it. When this occurs,
the automatic system interrupts the procedure and reverses the effect
of the signal given in error by actuating the boot lid against the
original direction of movement - in the case of unintended opening, the
second kick closes the boot lid again.
An appropriate safety
program facilitates unhindered use of the HANDS-FREE ACCESS system. An
acoustic signal provides the information that an opening or closing
procedure has been initiated, and an automatic reversing function stops
the boot lid as soon as the system recognises that there is an obstacle
blocking the boot lid.
For the HANDS-FREE ACCESS system to be
included, the vehicle must be fitted with KEYLESS-GO - this allows
non-contact access to the vehicle In addition to this the correct
KEYLESS-GO vehicle key has to be in the vicinity of the vehicle, so in
order to open the doors it can, for example, stay in the driver's coat
pocket or handbag. In order to activate the HANDS-FREE ACCESS system for
the boot lid, the KEYLESS-GO key must not be further than 1.5 metres
away from the rear end of the vehicle.
Body and bodyshell: Aluminium comes up trumps
Cars
are becoming increasingly safer, more comfortable, but often heavier as
well. The new Mercedes-Benz SL not only stops this trend, it turns it
around. In spite of increased comfort, performance and safety, it is 140
kilograms lighter than its predecessor.
The greater part of the
weight-reduction "diet" is hidden from the eyes of the observer of the
SL. Under the aluminium outer skin there is a bodyshell made almost
entirely from aluminium, only very few components being made from other
materials. The even lighter magnesium is used in part for the cover
behind the tank. The A-pillars and the roof frame are of steel sheet
metal incorporating high-strength steel tubing. For these elements steel
is the best solution to provide survival space for occupants in the
event of the vehicle overturning.
The bodyshell of the
Mercedes-Benz SL-Class is the first all-aluminium bodyshell to be
produced in large series at Mercedes-Benz. This entirely new development
weighs 254 kilograms and is thus 110 kilograms lighter than a
comparable steel bodyshell. Further extensive lightweight design
features compensate the additional weight unavoidably caused by the
increased comfort, the new assistance systems and other technical
features. Under the bottom line an enormous weight advantage remains for
the new SL. As the SL500 it weighs 125 kilograms less than its
predecessor, while the SL350 weighs 140 kilograms less than its previous
version. And its preceding model already had a lightweight aluminium
bonnet and doors.
"The effect is rather as if a heavyweight-class
passenger had got out of the car and taken their heavy flight luggage,
too" says Dr Thomas Rudlaff, responsible for the aluminium bodyshell at
Mercedes-Benz. "The result is perceptible and measurable. Less weight
means more dynamism and less consumption. In other words: the motoring
enjoyment increases and the environmental burden decreases."
For the roadster the aluminium bodyshell is superior to a steel construction
The
developers at Mercedes-Benz did not rest content achieving weight
benefits alone. The aluminium structure had to be superior to a steel
construction in terms of rigidity and comfort as well. In order to
attain this high objective, developers consistently went for an
intelligent lightweight construction, and explored many new paths to do
this. Every single component of the aluminium bodyshell was specifically
optimised for its particular function and expected loads. Thus, diverse
processes are used to make different kinds of aluminium depending on
the use the component is to be given: the parts are made by chill
casting or vacuum die casting, worked into extruded aluminium sections
or into aluminium plates of thicknesses that vary within one and the
same component; these are what are known as the tailored welded blanks.
Expressed in numbers, the bodyshell weight is made up of: 44 percent
cast aluminium, 17 percent aluminium sections, 28 percent aluminium
sheet metal, 8 percent steel and 3 percent of other materials.
At
the Bremen production facilities the parts are assembled using diverse
load-adequate joining methods, some of which are innovative processes.
Secure joints are ensured, for example, by MIG welding, hemming,
bonding, self-piercing rivets, flow hole bolting, or friction stir
welding - a joining method by which a highly resistant weld seam is
produced by means of friction heat; a method particularly well-suited to
aluminium on account of its low melting point.
Particular highlights of the bodyshell:
- The firewall is at present the largest aluminium cast component made in large series for vehicle bodywork
- Many
sheet metal parts are designed in such a way that for the first time
they can be made from 100-percent recycled aluminium, saving 80 percent
of the energy used in their production.
- The main floorpan
consists of a 3-layer shaped panel made from thin, extrusion-moulded
hollow sections, welded together by friction stir welding.
- The
longitudinal members in the vehicle front end are made using
high-pressure hydroforming (IHU) technology, which enables the creation
of highly complex and robust components, permitting optimum use of
reduced installation spaces.
- The door sills (longitudinal
members) consist of 1.7 metre-long, 7-chamber extrusion-moulded
aluminium sections; these provide rigidity in the lateral sectors and
safety in the event of a collision. Flexible chamber distribution makes
possible a minimum component weight coupled with optimum
characteristics.
- The tunnel is made of aluminium sheet metal
with a reinforcement of varying thickness (3 different thicknesses
depending on the sector, a so-called tailored welded blank, TWB).
- The
rear sector floor is a MIG welded frame with a hollow chilled cast
longitudinal member as its central element. This technique is employed
in the SL for the very first time in automotive bodyshell construction.
- The rear sector floor frame structure is closed by floor sheet metal panels and the boot tub made by vacuum die-casting.
- The boot recess is made from recycled sheet metal.
- The
central member connects the front end with the rear sector floor. The
mounting points for the drive shaft, the transmission cross beam, the
transmission tunnel braces and the seat bolting points on the tunnel
side are all integrated into a single element. The wall thicknesses and
rib distribution are oriented bionically towards the requirements and
loads.
- Many other components were optimised bionically, i.e.
based on examples from the natural environment. These structures reduce
the vehicle weight compared to a classic design even further.
The
sum total of all the design measures leads to a lightweight,
torsionally and flexurally rigid bodyshell with an optimum
rigidity/weight ratio. It was possible to increase the bodywork's
torsional rigidity by more than 20 percent over the already highly rigid
preceding model series. This is confirmed by measurements of the new
SL's torsional strength - at 19400 Nm per degree the roadster achieves
an absolute top value (its predecessor already reached 16400 Nm per
degree).
Meets the highest safety standards
At
the same time the high-strength structural elements of the aluminium
bodyshell make the new SL even safer than the preceding model in the
event of a collision. Extrusion-moulded sections, connecting cast nodes
and a double-thickness plate floor form a passenger compartment that is
just as lightweight as it is sturdy. Two aluminium sections in each door
together with the side sills (very rigid thanks to their internal
chamber structure) and crash-resistant seats provide the greatest
possible survival space in the event of a side collision.
A front
end deformation zone acting on several levels and in which the aluminium
front axle subframe is integrated as an additional third longitudinal
member, distributes collision forces to a large area, conducting them
past the passenger compartment. And in the rear, too, there is
sufficient energy-absorbing deformation potential. A structural cage
made from chilled cast longitudinal members, transversal sections and a
cast magnesium tank separation bulkhead also contribute to this. This is
also where the fuel tank is nested in a crash-protected manner above
the rear axle. This way all the
statutory safety requirements are met as well as the even stricter ones from Mercedes-Benz.
Best marks for NVH comfort
Thanks
to its innovative aluminium bodyshell concept, the new SL is also
unique among the roadsters in terms of NVH comfort (noise, vibration,
harshness). One contributing factor towards its optimum vibration and
road roar characteristics is a very rigid connection between the front
section and rear floor, allowing relaxing travel even over long
distances, and at the same time offering impressive driving dynamics.
Although
aluminium features a higher sound emission and radiation level than
steel, the new SL is the quietest vehicle in its class. Mercedes-Benz
compensates for the acoustic disadvantages of aluminium by means of a
consistent sound insulation concept with targeted adaptation of the
sound damping materials to each problem zone, and through the use of
innovative sound-insulation materials:
- A special firewall damping with variable mass distribution and a significant heavy layer proportion attenuates engine noise.
- In
conjunction with the plate floor, single-piece, foam-backed carpeting
with virtually no seams reduces the roll noise of the vehicle in the
interior.
- A spray-on lining attenuates the structure-borne sound in the vehicle interior and exterior.
- Textile
wheel arch linings, acoustically absorbing shield plates and bodyshell
foam elements for critical sectors also contribute towards a smooth
ride.
- Damping in the rear wall transversal cross member and boot
lateral elements as well as in the forced ventilation openings prevent
disruptive tyre and wind noises from making themselves unpleasantly
noticeable in the vehicle interior.
A further contribution
to the good interior acoustics is the laminated glass windscreen with
acoustic film. The transparent, highly resilient film absorbs the
vibrations of the windscreen and reduces the perceptible sound level in
many frequency ranges.
The precision workmanship on the acoustics
goes so far as to ensure that the hydraulic pump for the
electrohydraulic vario-roof is encapsulated and decoupled from the
bodyshell. In addition to this, a newly developed insert nozzle sees to
it that the pressure pulsation in the pump is reduced to a minimum right
from the outset. This means that pump noises are only barely audible
for the driver and passenger.
The doors and the bonnet, too, are lightweight
The
intelligent material mix is completed by the boot lid, of SMC-hybrid
design (SMC = sheet moulding compound). It consists of a single-shell
synthetic material panel mounted on a steel reinforcement. Both
materials have virtually identical thermal expansion coefficients and
complement each other very well. The interior steel construction permits
maximum rigidity with minimum use of space, while the plastic panelling
allows the full integration of the aerials for navigation, digital
radio and mobile telephony out of sight in the rear area so that the SL
does not need to carry a bothersome aerial stump on its aerodynamically
refined body.
The bonnet of the SL is made from aluminium, as was
that of its predecessor. It was optimised in terms of form and
materials, contributing towards the outstanding pedestrian protection.
The
doors, too, are of a lightweight design and made from aluminium. They
are fashioned from a combination of sheet metal, extruded sections and
cast metal parts, joined by diverse methods: riveting, bonding and
hemming. Their aluminium and steel hinges are friction-based and are
infinitely adjustable to any desired angle when opened, so that when
getting into or out of the car they can remain securely open at any
angle permitted by the space available at the side. This is particularly
desirable in cramped parking conditions such as in a garage or car
park.
Unique item of equipment: MAGIC SKY CONTROL
The
proven electrohydraulic vario-roof - which turns the roadster into a
closed coupé with a fixed roof in just a few seconds at the push of a
button - has been intelligently enhanced, with Mercedes-Benz continuing
to play the pioneering role here. For the new SL Mercedes-Benz is for
the very first time offering drivers the choice between three variants
of the lightweight-construction vario-roof:
- The base version is a roof painted in the vehicle colour
- As an alternative, a transparent variant with a roller blind can be selected
- The
third variant from which drivers can choose is the panoramic vario-roof
with MAGIC SKY CONTROL. This glass roof switches to light or dark as
required at the press of a button. When light it is virtually
transparent, offering an open-air experience even in cold weather. In
its dark state the roof provides welcome shade and prevents the interior
from heating up when the sun's rays are very intense. In other words: a
feel-good atmosphere at the touch of a button
The operating
principle is based on the physics of a plate condenser: if the glass
structure is subjected to an electrical voltage, particles in the
structure position themselves so that light is able to pass through the
glass. If the voltage remains switched off, however, the particles
position themselves randomly. This partially blocks the light, and the
glass remains dark. The control unit and converter are integrated into
the front section of the roof, and the switch is in the overhead control
console.
In addition to the unique panoramic effect and
transparency at the touch of a button, MAGIC SKY CONTROL also provides
an atmosphere of wellbeing. UV and infrared light are also effectively
blocked in transparent mode, while insulation increases even more
significantly in the darkened mode, thereby helping to keep the
temperature on interior parts such as armrests cooler by up to ten
degrees Celsius compared with conventional green glass.
Since the
innovative glass also shields against the sun's rays far more
effectively than conventional thermal insulation glass or sunblinds, the
occupants of the new Mercedes-Benz SL-Class will also enjoy the highest
level of climatic comfort at the same time. When driving with the roof
open would be unpleasant due to intense heat, the driver and passenger
are able to remain composed under the MAGIC SKY CONTROL roof - making an
important contribution towards driver-fitness safety, a concept which
Mercedes is well known for promoting. Even when the vehicle is at a
standstill the interior does not overheat, since the roof is switched to
darkened mode when powered off.
But MAGIC SKY CONTROL not only
benefits the occupants. Some of the strain is also taken off the air
conditioning, thereby saving on CO2 emissions.
The frame of the
three roof variants is now made of magnesium. This makes each roof
around six kilograms lighter than in the previous model, giving the car a
lower centre of gravity, and therefore better agility.
The
engineers have refined the operating mechanism for the roof and boot
lid. It now takes less than 20 seconds to open or close the roof
completely.
Sophisticated corrosion protection concept
The
aluminium bodyshell of the new SL offers no point of attack for
corrosion. A sophisticated surface protection concept ensures the
preservation of the brilliant look both of the outside skin and of the
underside of the sheet metal panels, thus simultaneously protecting the
renowned reliability and value stability of Mercedes-Benz vehicles. The
protection concept was developed and tested on the basis of the
environmental burden in different climate zones of the world and the
specific loads the vehicle is subjected to.
The foundation for
maximum corrosion resistance is formed by corrosion-resistant aluminium
alloys and design features, while the few steel vehicle components are
all fully galvanised. High-quality zinc/nickel coatings or special
electrochemical insulation measures prevent contact corrosion with
aluminium. All the seams are meticulously sealed, the surfaces protected
through cathodic dip priming and multiple coats of paint. Sectors
particularly exposed to corrosion are additionally protected with wax,
to ensure that the pristine aspect of the new car is preserved for a
long time.
Intelligent Light System and LED tail lights as standard
The
headlamps on the new SL have been enhanced. As part of its standard
specification, the new roadster is equipped with the Intelligent Light
System (ILS) featuring bi-xenon headlamps. A driving direction
indicator, sidelights and the daytime running lamps with LED technology
complete the Intelligent Light System.
The tail lights on the new
SL benefit from the advantages offered by the LED technology. LEDs light
up approximately 150 milliseconds faster than conventional bulbs, plus
they have a considerably longer life and conserve current. In the SL's
tail lights, the LEDs also light up with differing intensity in a
targeted manner in certain sections of the tail lights, depending on the
light function. This technology ensures an unmistakable night design.
Rear
reversing lights and rear fog lamps are integrated into the rear
bumper. The third brake light featuring LED technology is integrated in
the boot lid above the Mercedes star.
Lightweight construction under the microscope: Progress in detail
Right
from the word go the target was ambitious: the aim was for the new
Mercedes-Benz SL-Class to tip the scales weighing five percent less than
the previous model. Already declared the benchmark, the predecessor
itself was a shining example boasting various lightweight design
measures, even including bonnets made of aluminium. At the same time,
the specifications book prescribed more comfort, more output coupled
with considerably reduced consumption and fewer emissions, plus a more
rigid bodyshell and even more safety. These demands would render the
vehicle heavier and not lighter - that was clear. The experts calculated
a weight increase of at least 75 kilograms.
Only a lightweight
construction on a totally new level - which included all the vehicle
components in the equation - could reconcile these contradictory
requirements. In actual fact, the developers at Mercedes-Benz have
succeeded in undercutting the ambitious weight targets. The new SL500
weighs no less than 125 kilograms less than the predecessor of the same
name. This corresponds to a reduction of 6.5 percent. Meanwhile the
SL350 even manages to exceed the high expectations even further - with
its weight saving of 140 kilograms - equating to 7.7-percent less.
Bodyshell.
Converting the entire bodyshell to aluminium cuts its weight by 24
percent in contrast with a steel bodyshell featuring comparable
properties (a weight saving of 110 kg). Even the upper door hinges
consist of aluminium.
Damping. The switch from absorber foams to
sprayable acoustic compositions with variable layer thicknesses which
can be shaped according to requirements, plus modified underbody
panelling, results in weight savings in the order of 2.5 kg.
The
guide rails for the window lift mechanisms are now comprised of
aluminium instead of steel, amounting to a weight saving of 0.5 kg.
Vario-roof
in magnesium/plastic design.The front part of the roof and the C-pillar
are produced in magnesium/plastic, plus there are additional
optimisation measures regarding the design of the tubular frame, rear
shelf, rear window frame and roof frame. The weight reduction amounts to
15 kg.
Glazing. The windscreen is 0.5 millimetres thinner, with an acoustic film. The weight reduction amounts to over 1 kg.
The rear windscreen is 0.7 millimetres thinner, resulting in approximately 1 kg less weight.
Interior.
The dashboard mount consists of a continuous IHP aluminium tube with
magnesium struts and moulded-on polymer brackets. The weight reduction
is 2.2 kg.
With the introduction of shift-by-wire technology, the
large shift lever has been replaced by a joystick-like lever. This
DIRECT SELECT gearshift system weighs only one sixth as much as the
automatic selector lever used in the preceding model. The weight saving
is 1.4 kg.
The boot floor is in the form of a polyurethane
honeycomb plate instead of the wood plate previously used. The
passenger's foot plate has been switched over to plastic from steel,
saving 1.5 kg in weight.
Seat. New seat structure with new
adjustment motors, but a standard-fit 4-way lumbar support and
crash-responsive head restraint. Weight savings: 11 kg.
Electrics.
Thanks to an intelligent dynamic load management system, two batteries
are no longer necessary; one 95 Ah battery in the boot is sufficient,
supported by a 12 Ah battery for the ECO start/stop function. Weight
savings: approx. 4 kg.
Every vehicle is given a customer-specific
wiring harness for the interior, cockpit and engine compartment. Thanks
to this tailor-made cable harness, additional weight in the form of
wires which are surplus to requirements can be saved - to the tune of up
to 0.4 kg.
The innovative Frontbass system avoids the need for a separate woofer and door loudspeaker. Weight reduction: over 4 kg.
Axles.
The four-link front axle had already undergone extensive weight
optimisation for the preceding model, featuring steering knuckles and
spring links made of aluminium. The two front-axle halves now consist
entirely of this material. The integral support frame for the front-axle
halves, steering gear and engine is also produced in aluminium. Total
weight savings: 11 kg.
The rear-axle subframe consists of
high-strength steel with adapted panel thicknesses. It has been
optimised in accordance with the specific engine line-up for the SL350,
resulting in a weight reduction of 2.6 kg over the SL500.
Suspension,
Damping. The standard-specification semi-active adjustable damping in
the SL350 is lighter than the standard suspension system, saving 10 kg
in weight.
Brakes and pedals. Optimised brake cooling eliminates
the need for large and thus heavy brake discs on the front axle. Weight
savings: 3.8 kg.
Lightweight wheels. New standard-fit lightweight
wheels for the SL500 are around 15 percent lighter than cast wheels.
Weight saving: approx. 4 kg
Wheel bolts with a weight-optimised head. Weight saving: approx. ¼ kg.
MAGIC VISION CONTROL adaptive windscreen washing system: Visibility as if by magic
An
astonishing experience: the wiper blade glides over the badly soiled
windscreen of the new SL, without a sign of a cleaning water jet, the
occupants do not notice anything yet the windscreen is still cleaned!
The new SL is the first vehicle to be equipped with the adaptive MAGIC
VISION CONTROL wiper/washer system developed by Mercedes-Benz. It cleans
the windscreen without the splash of water that usually briefly
disrupts the driver's field of view in the case of conventional
windscreen washing systems - something that is especially unpleasant at
night or when the sun is low in the sky and at high speeds.
In
fact, the windscreen cleaning operation in the Mercedes-Benz SL-Class is
still performed with washer fluid in the conventional manner. The
innovation lies in the way the fluid is conducted to the windscreen in
order to clean it. This is done by means of water guides integrated on
both sides along the wiper blade - one on the left and one on the right -
with minute laser-cut spraying holes. Via these channels, the
innovative washer/wiper system always supplies washing fluid to the
windscreen discreetly, precisely where it is needed: just in front of
the wiper blade lip, according to the direction of movement of the
wiper. The holes are distributed along the entire length of the wiper
blade, being more closely spaced towards the outside of the blade, where
it sweeps a greater area, than closer in, where the area swept is
smaller.
Programs for summer, winter and cabriolet operation
Mercedes-Benz
controls the MAGIC VISION CONTROL system intelligently via three partly
autonomous wash programs - for summer, for winter and for cabriolet
driving. It is the first windscreen wipe/wash system anywhere in the
world to operate in this way. In summer, small quantities of water are
sufficient to remove a light powdering of dust. In winter the dirt mixed
with de-icing salt requires a greater amount of water. The MAGIC VISION
CONTROL system works in accordance with the outside temperature, and it
also automatically adapts the washer fluid quantity to the surrounding
conditions.
A particularly interesting feature of the SL Roadster
is the Cabriolet function: when the hardtop is down, the electronic
control system reduces the amount of water, apart from which it demands
the required water mainly on the downward stroke of the wiper arm. This
way the windscreen can be conveniently cleaned during the journey and
with an open roof, without any of the water spraying into the vehicle
interior. Another pleasant side effect is that, since the washer fluid
is directed specifically and in a well-metered manner to the area to be
cleaned, one doesn't douse anyone else in the surroundings with water,
either, and it also doesn't distribute any spray onto the vehicles
behind. At the end of the day, a better cleaning effect is attained with
up to half the amount of washer fluid. It has therefore been possible
to reduce the volume of the washer fluid reservoir by 1.7 litres
compared with the preceding model. This in turn contributes to a
reduction in weight and consequently to greater efficiency.
Winter-proof thanks to the heated system
On
request the MAGIC VISION CONTROL wiper blades are completely heated on
the new SL, making Mercedes-Benz the first manufacturer in the world to
offer a fully heated wiper/washer system. It consists of a washer fluid
container heated through coolant waste heat, electric heating for the
entire hose system and, as a newly-developed highlight, a fully heated
wiper blade. This effectively prevents the formation of snow on the
wiper blades, so typical in winter. To do this each of the spring rails
of the blade is equipped with a heater foil with an output of 35 watts
per blade. It heats the spoiler and the wipe lip. Snow and ice cannot
freeze onto the blade; it remains supple in winter, too, and always
cleans well.
The heating is also controlled as required according
to the duration of operation and the outside temperature. It is only
below a temperature of minus 20 degrees Celsius that the system makes
use of the entire system's maximum output, 270 watts. Between 5 degrees
above and 20 degrees below zero the heating operates in an energy-saving
mode and only requires the output needed to thaw out the wiper/washer
system and keep it free of snow and ice.
Aerodynamics: Breezy, but never bothersome
Open-top
motoring should be nothing but sheer pleasure: smelling the forests and
meadows, hearing the birds singing, savouring the sound of the sea,
feeling the warmth of the sun. And in spite of this proximity to the
natural world, the occupants in the new SL do not have to relinquish
comfort. Even at higher speeds they are largely unaffected by any strong
winds. In this respect, just like its predecessor, the new luxury
roadster is unsurpassed by no other open-top two-seater.
First and
foremost it is the rigid aluminium bodyshell and - one of the brand's
hallmarks - sophisticated aerodynamics which ensure excellent comfort
during open-top motoring. The designers' intelligent and highly
efficient work has resulted in superb aerodynamic properties for the SL
in several respects. This means that the roadster earns top marks in no
less than four important disciplines within its segment:
- Best cd figure
- Wind noise on a par with a saloon
- Open-top motoring in maximum comfort
- Best anti-soiling measures
Top-class: cd figure
The
new SL shines with a cd figure of 0.27 (in the SL350). Never before has
a vehicle in the roadster segment achieved such a low cd. At the same
time, the cLR value (the coefficient of lift at the rear axle), which is
decisive when it comes to braking stability, is reduced by 0.01. This
ensures a lower lift at the rear axle than at the front axle - which is
important for comfortable, safe handling at high speeds and/or when
there is a crosswind.
The fact that not only could the cd figure
be cut to a record low but that it was also possible to reduce the wind
resistance as a whole is even more astounding when taking into account
the fact that the new SL's frontal area is around four percent larger
than that of its predecessor - due in part to its wider track. The
product of the frontal area and the cd figure is, however, smaller.
Alongside a great deal of precision work, some of the other factors which contribute towards the low cd figure are:
- a complete engine compartment and underbody panelling concept,
- a spoiler lip on the top face of the boot lid,
- a specifically designed spoiler lip on the tail light,
- wheel spoilers in front of the front and rear wheels, and
- redesigned exterior mirrors positioned on the beltline and with a mirror base specially optimised for the new SL.
A
newly developed aero wheel which is part of the standard specification
for the SL350 also significantly reduces the wind resistance. Its rim
section is largely closed, which means that the air flowing through the
wheel to the exterior disturbs the air flowing past at the outside of
the wheel than is the case with a conventional wheel. Together with
tyres which have been specially tuned to this end, the aero wheel cuts
the frontal area - which is also a decisive factor in determining the
wind resistance - by 0.01 square metres. This pays off in the form of a
reduction in consumption, which results in one gram per kilometre fewer
carbon dioxide emissions.
In order to minimise wind resistance
even further, the six-cylinder version of the new SL also employs an
adjustable radiator shutter. This consists of a large number of louvres
and is positioned between the radiator and the radiator fan. An actuator
fixed to the engine's cooling module can be turned to close or open the
flow path of the cooling air. In this way the flow of air through the
radiator and through the engine compartment can be regulated as
necessary. This means that if the engine has low-level cooling
requirements, the wind resistance falls, as do the fuel consumption and
emissions.
Top-class: wind noise on a par with that in a saloon
Where
wind noise is concerned, the predecessor of the new SL was already the
benchmark in its segment. But its successor surpasses this high level.
It is even possible to hold a conversation, listen to the radio and make
a telephone call at high speeds. This is thanks in part to the new
stand for the exterior mirror. Its shape facilitates optimum flow; both
when the inflow is straight and in the case of crosswinds it causes only
low wind noise.
The windscreen fitted with multi-layer foil also
contributes towards the exemplarily low interior noise, combining a low
component weight with good acoustic properties. Low-frequency sounds
which can arise through vibrations in the vehicle's bodyshell can to a
large extent be prevented by the new SL's aluminium bodyshell, through
design measures which were taken into account and tested at an early
stage.
Top-class: maintaining a draught-free interior
Even
at speeds of around 200 km/h the new SL offers extraordinarily high
comfort during open-top motoring, setting new standards here. When the
vario-roof is closed and the side windows are lowered, a welcome breeze
can be felt during hot weather. Even putting the side windows up
tangibly reduces it. The occupants in the new SL enjoy a comfortable and
virtually draught-free ride as soon as they use a draught-stop. A
conventional, manually operated folding-frame draught-stop comes as part
of the standard specification. Covered with a finely meshed, synthetic
textile fabric, this draught-stop is mounted behind the seats and folded
up by hand. It covers the entire area behind the seat backrests as far
as the upper edge of the head restraints. It can be taken off and stowed
in the boot as necessary.
A highlight comes in the form of a new
electrically operated draught-stop which is available as an optional
extra. This new development can also be extended and retracted by the
driver or passenger during the journey, via a switch in the centre
console. If the switch is operated, a trapezoidal frame is unfolded
electrically, and when it reaches its final position a finely meshed
textile fabric covers it, thus keeping the area behind the occupants
virtually free of draughts. Once it has been retracted, the frame
disappears completely in the rear compartment trim cover.
The
innovative neck-level heating system AIRSCARF is also available as an
optional extra. It emits preheated air from an orifice in the head
restraint, and this warm air then wraps itself around the neck area of
the occupants like an invisible scarf, therefore even making it possible
to have the roof open when the temperature is cool, without any serious
inconvenience.
Top-class: anti-soiling measures
Clean
exterior mirrors and side windows are important factors where safety is
concerned, yet all too often drivers cannot take them for granted. In
this respect, the new SL profits from the detailed work carried out by
the aerodynamics engineers and can to a large extent ensure clear vision
for drivers - even when it is raining. This is achieved mainly through a
precisely tuned package of anti-soiling measures. The A-pillar trim
with a new shape features an aerodynamically and aeroacoustically tuned
front edge and a water guide channel on the top edge prevent water from
flowing from the windscreen to the side windows. The new exterior mirror
has also been optimised for journeys during rainy weather. Water guide
runnels and additional drip edges have been integrated into its housing,
and to a large extent they keep water away from the mirror glass, and
shift the break-away point of the droplets to the outside. As a
consequence of the aerodynamic measures the side windows soil only
slightly.
Engine and drive system: The power and the economy
Rich
power reserves plus modest fuel consumption - this formula describes
the fundamental characteristics of the new SL models. They owe this in
part to the two V6 and V8 units from the new generation of BlueDIRECT
engines from Mercedes-Benz. As is already the case with the S-Class and
the CLS, they now also enable the SL to achieve previously unattained
marks for efficiency in its segment. The V8 in the new SL500 has at its
disposal 4663 cubic centimetres of displacement from which it achieves
320 kW (435 hp) - so in spite of having around 0.8 litres less
displacement that's some 12 percent more than its predecessor (285
kW/388 hp). The consumption, meanwhile, falls by up to 22 percent, with
the torque increasing at the same time from 530 Nm to 700 Nm - an
increase of 32 percent. The V6 engine for the SL350 has the same
displacement as its predecessor - 3499 cubic centimetres - from which it
now achieves 225 kW (306 hp). Whilst this means that its output is 7 kW
less than the engine in its predecessor (232 kW/315 hp), as the torque
simultaneously climbs from 360 Nm to the current figure of 370 Nm, there
is no perceptible loss of power - on the contrary, in fact: when
accelerating, the new SL350 even proves superior. Plus the new V6
impresses with its outstanding consumption figures. It is content with
6.8 litres over 100 kilometres, making it almost 30 percent more
economical than its predecessor (9.7 l/100 km).
Thanks to the
economy of both engines, it has been possible to decrease the volume of
the fuel tank from 80 litres to 65 litres. Nevertheless a greater range
is available than was the case with the predecessor.
Of a torquey disposition when sprinting
The
acceleration times from 0 to 100 km/h go to prove that economy does
nothing to dampen torquey spirits. Despite a nominal reduction of 7 kW,
the SL350 covers this sprint in 5.9 seconds, which is three tenths
faster than its predecessor. From a standstill the SL500 races to the
100 km/h mark in 4.6 seconds, making it eight tenths faster than the
previous SL500.
Both engines are exemplary when it comes to
in-gear acceleration, too. Proof positive can be found in acceleration
from 80 to 120 km/h in 4th gear, for only good figures facilitate fast
and safe overtaking on rural roads. 5.5 seconds for the SL350 and 3.2
seconds for the SL500 make the new SL's excellent characteristics in
this discipline plain for all to behold.
"The new BlueDIRECT
engines in the SL with six and eight cylinders form a unique synthesis
of effortlessly superior power delivery, comfort and consuption",
comments Professor Dr Thomas Weber, responsible for corporate research
and development at Mercedes-Benz Cars on the Board of Management of
Daimler AG. "Both impress in the new SL, delivering refinement of the
highest calibre and exemplary environmental acceptability."
The V8 is in a new league of its own
The
new V8 was systematically enhanced on the basis of the very successful
predecessor. Mercedes-Benz engineers primarily achieved a high output
for a lower displacement by using one turbocharger for each bank of
cylinders. The turbochargers were configured to provide high torque even
at low engine speeds - compared to the previous engine, the result is
an increase of more than 40 percent at 2000 rpm. A superb 700 Nm are
available between 1600 and 4750 rpm.
The V6 impresses with its low fuel consumption and high comfort
The
new six-cylinder is a naturally aspirated engine. The most striking
change between the new V6 unit and its predecessor is a reduction in the
V-angle between the cylinder banks from 90 degrees to 60 degrees. This
enabled the balancer shaft counteracting primary vibrations to be
omitted, and as a result the driver registers an outstanding level of
comfort.
Innovative technology makes V6 and V8 engines fit for the future
Both
the new V6 and the new V8 from Mercedes-Benz are derived from their
predecessors. They have aluminium crankcases, pistons and cylinder
heads. The crankshaft, connecting rods and valves are of special forged
steel. Practically all the details were, however, newly developed or
revised with the aim of achieving more fuel economy, more output and
more refinement.
The technology package in the new engine generation includes a number of new developments that are unique in this combination:
- In
combination with multi-spark ignition, a further developed,
3rd-generation direct fuel injection system with spray-guided combustion
and piezo-electric injectors offers further possibilities for fuel
savings - in the V8 by means of an improved, homogeneous combustion
process, and in the V6 by a new, stratified combustion process with a
considerably extended characteristic map and fuel-efficient lean-burn
technology.
- In conjunction with the ECO start/stop function,
shift point adjustment and systematic friction-reducing measures,
improvements in day-to-day fuel consumption of up to 30 percent are
possible.
- Power consumption by ancillary units has been reduced.
These include an optimised water pump with 2nd-generation thermal
management, a demand-controlled oil pump, a volume-controlled
high-pressure fuel pump and an intelligent generator management system.
ECO start/stop function with direct-start
The
standard-specification ECO start/stop function operates with
starter-supported direct-start. This means that when the engine is
switched off, the attitude of the crankshaft is registered by a new
crankshaft sensor so that the engine control unit knows the positions of
the individual pistons. On restarting, it can then select the cylinder
that is in the most suitable position for first ignition. After the
starter has briefly turned over the engine, reliable injection, ignition
and combustion is immediately possible there.
An additional,
demand-controlled electric transmission oil pump supplies the clutches
of the automatic transmission with oil pressure prior to starting, so as
to enable a swift resumption of the journey after direct starting of
the combustion engine via the ECO start/stop function. The starter motor
(starter) has also undergone thorough modification: it is now designed
to be highly durable, ensuring that it will last a car's lifetime in
continuous urban driving involving frequent auto-starting. In addition,
the on-board electrical system is supported by a second battery. As is
the case with the starter battery (95 Ah), the "auxiliary battery" (12
Ah) also features maintenance-free AGM technology (AGM = absorbed glass
mat).
Intelligent alternator management
Its
intelligent alternator management also contributes to the luxury
roadster's sensitive treatment of energy. When the battery is charged to
more than 80 percent, the alternator is governed to take load off the
engine. The energy required in this operating state is supplied by the
battery. If the driver removes their foot from the accelerator pedal or
applies the brakes, kinetic energy is recovered and fed to the battery.
Automatic transmission for less consumption and more fun at the wheel
All
Mercedes-Benz SL-Class models come with the 7G-TRONIC PLUS automatic
transmission as standard. Now in its sixth generation, the multi-ratio
automatic transmission was developed by Mercedes-Benz and has been
produced since 1960. The new version has once again been thoroughly
revised to optimise consumption and comfort compared with its
predecessor. The new generation of the torque converter provides an
improved dynamic response and reduced noise and vibration levels thanks
to a new hydraulic circuit, as well as enhanced dampers and an optimised
torque converter housing. The extreme wheel-slip reduction of the
torque converter housing, combined with
- larger mechanical damper de-coupling, helps to reduce consumption significantly;
- in addition, the gearshift program in ECO mode has been changed in favour of lower engine rpm at cruising speeds;
- friction-optimised
bearings and seals plus a new automatic transmission oil (FE-ATF) with
reduced viscosity in conjunction with an optimised additive package.
This
results in more driving enjoyment than was the case with the
predecessor transmission - and also improved smoothness, not to mention
an average of seven percent less consumption (in the NEDC).
What's
more, the increased durability of the new oil also brings with it new
oil-change intervals from 50,000 (old) to 125,000 kilometres (new).
DIRECT SELECT gearshift with designer chic and athletic allure
Mercedes-Benz
is equipping the new SL with the newly developed DIRECT SELECT
gearshift in the centre console - the first vehicle with an automatic
transmission to receive this honour. In so doing, the premium brand is
establishing a completely new generation of central gearshift for
vehicles featuring shift-by-wire (ShW) transmission technology. Its
small control lever, reminiscent of a high-calibre joystick, has a
driver-oriented position, being installed on the centre console. Its
striking design not only underlines the sporty character of the
roadster; it also emphasises the high quality of the SL with its
exquisite touch and feel, superb ergonomics and unique look.
In
addition to an Eco program, the 7G-TRONIC PLUS in the new SL also offers
a sports-oriented automatic program. Over and above this, the driver
can also select a manual shift program which they operate via the
paddles on the steering wheel - which also come as part of the standard
specification.
The two automatic programs automatically adjust on a
continuous basis in line with the driver's behaviour. By way of
example, if they step on the accelerator pedal more dynamically than
before, the shift points automatically move towards more sportiness. In
the ECO mode, the shift program is configured differently for lower
engine speeds during cruising, thus saving fuel.
In the sportily
oriented automatic program, the output is available more spontaneously
and it shifts faster. The double-declutching function and active
downshifts have been systematically enhanced. During heavy braking, the
transmission shifts down considerably earlier, so higher engine speeds
make the acceleration which follows easier. The double-declutching
function, in which the engine speed is actively raised with an abrupt
acceleration, ensures faster and more comfortable downshifting. The
concomitant acoustic response underlines a sporty driving style and
enhances the unique roadster feel.
In the manual transmission mode
controlled using shift paddles on the steering wheel, the engine
responds to the throttle over a steeper characteristic pedal curve.
Selecting the gear via the steering-wheel gearshift buttons facilitates
minimal shift times and emphasises the sporty double declutching. In
manual mode, the gear indicator in the instrument cluster moves to a
separate section of the colour display, where it shows the seven
available gears plus the gear currently selected.
Chassis and suspension: Best contact with the road
Powerful
when accelerating, effortlessly superior at every speed, zappy on
winding stretches - the new SL is a shining example, displaying perfect
manners on all the world's roads and in all driving situations. What's
more, it also pampers all the senses with any amount of fun at the
wheel. For these emotive experiences SL drivers can thank the potent
engines - and above all the sporty, agile tuning of the suspension -
which is nevertheless very comfortable, being offered in the form of two
different systems for the SL:
The Mercedes-Benz SL-Class features
semi-active adjustable damping as standard. The optional active
suspension system ABC (Active Body Control) is offered as an
alternative.
The spring struts which come as part of the standard
equipment combine a steel spring with a continuously adjustable damper.
Its damping properties can be varied via an electrically controlled
valve.
Continuous adjustment of the damping in accordance with the
respective driving situation is taken care of fully automatically by
control electronics which record the driving condition in question via
sensors. The control unit uses the sensor data to determine the
necessary damping forces for optimum comfort and handling. On this basis
it steplessly regulates the damping valves at every wheel within a
broad damping characteristic so that sprung mass vibrations such as
lifting, rolling and pitching are minimised on uneven roads. As a
result, the new SL gives its occupants a smooth ride even on poor roads,
without relinquishing any driving dynamics.
The semi-active
adjustable damping also rapidly counteracts sprung mass vibrations
caused by the driver, by adjusting the damping characteristics. By way
of example, the dynamic anti-roll and anti-pitch support compensates for
pitch ensuing from braking and accelerating, and quickly and
effectively stems rolling motion which is initiated above all by
cornering or jerking the steering wheel during a dynamic evasive
manoeuvre. Torsion bars at the front and rear axle help to reduce wide
roll angles when cornering, and positively influence the
understeer/oversteer characteristics.
Setting the basic
characteristics of the suspension is still left to the driver, however,
using a switch that enables them to choose from a broad spectrum ranging
from comfortable to sporty damping characteristics. At the touch of a
button they can therefore have a chassis and suspension set-up available
which places more emphasis on comfort, for instance, whilst if they
choose the sports setting, they are opting for a driving experience with
a very high level of dynamic response.
Sports suspension in the AMG Sports package
A
variant of this suspension is offered in the AMG Sports package. This
sports suspension lowers the roadster by ten millimetres, the spring
strut and torsion bars are configured to be ten percent more rigid and
the parameterisation of the adjustable damping is selected in such a way
that the sprung mass vibration is dampened more strongly - all measures
which underline the vehicle's sporty character.
ABC suspension for high levels of comfort
As
an option the new Mercedes SL is available with the unique active
suspension system ABC (Active Body Control) as an alternative. It has
been further improved for the new SL by the Mercedes-Benz chassis and
suspension specialists. This system's highly effective control elements
are spring struts with a hydraulic steel cylinder arranged in line with
the steel spring. When this cylinder retracts and extends, it actively
adjusts the length of the spring and therefore the spring force in the
spring strut. This eliminates the need for torsion bars at the front and
rear axle.
With this technology an automatically controlled
electronic system permanently adjusts the suspension to suit the driving
situation and the road condition without any perceptible delay. This
means that the active suspension system ABC can raise comfort to a high
level, whilst simultaneously improving the roadster's driving dynamics.
This is possible as it almost completely compensates the vehicle body's
rolling and pitching movements when accelerating, braking and cornering.
In addition to this, at the touch of a button it offers a unique,
further increased spread of suspension settings between sports and
comfort.
As the vibrations initiated by irregularities in the road
surface are greatly reduced, the occupants in the SL experience a
vehicle with perfect absorption capacity on poor roads. Above all it is
alternating sprung mass vibrations ("cross-pitching") which are
extremely minimal.
Sprung mass vibrations which arise through the
driver's influence are also almost entirely ironed out - this is the
case, for instance, when the body rolls during steering or when there is
pitching during braking and accelerating. The occupants experience a
vehicle which drives "as if on rails", but without having to pay for
this with the usual reduction in ride comfort which is typical of sports
suspensions.
As the ABC system modifies the roll torque
distribution depending on the driving speed, the driver experiences
handling which changes with the driving speed. It varies from motoring
pleasure where one can afford it in driving dynamics terms to
directional stability where it is most needed. In other words, on
winding rural roads the roadster moves with nimble agility, and on
motorway stretches it stays safely on track and does not worry the
driver with any nervous reactions.
The ABC system is also fitted
with a hydraulic all-round level control system, thus ensuring a
constant vehicle level irrespective of the load. When the engine is
running, the driver can raise the level of the vehicle at the touch of a
button, both when the vehicle is at a standstill and during the
journey. Thanks to a new feature in the SL, if the level is raised by 50
millimetres in this way, the ground clearance for rough roads or ramps
is increased. In addition, the SL fitted with ABC is automatically
lowered by up to 13 millimetres at high speeds, thus lowering the centre
of gravity and wind resistance - and therefore also the fuel
consumption.
More track, less unsprung weight
The
track and wheel suspension are the same in the case of both suspension
variants. In favour of sporty, agile and handling which can be safely
kept under control, the new Mercedes-Benz SL-Class has a considerably
wider track than the predecessor (front axle plus 38 mm, rear axle plus
63 mm).
At the front axle, the tried-and-trusted principle of the
4-link front suspension has been adopted from the previous model series.
It achieved superb results where comfort, dynamism, agility plus active
and passive safety are concerned. Most importantly they are
characterised by two individual links (a torque strut and a spring
link), which are included in place of a lower wishbone. In conjunction
with the ABC suspension no torsion bar is necessary.
In order to
optimise the front axle even further in terms of weight, in the new SL
the steering knuckle and the spring link are also made of aluminium. The
lower front axle elements, the steering gear and the engine mounts are
linked with an aluminium assembly carrier which is directly bolted to
the body.
A lightweight construction was also systematically
implemented at the rear axle, too. In order to reduce the unsprung
masses, virtually all the suspension parts are made of aluminium, as is
the subframe with load-matched panel thicknesses. The weight-reduced
rear axle carrier consists of high-strength steel.
But the focus
was not just on saving weight when developing the rear axle; the
engineers have also optimised the kinematics and elastokinematics, with
the objective of achieving more agility. Other results of the new
configuration are lower forces, which considerably increases comfort. An
additional support linking the rear subframe bearing to the bodywork
also has a positive effect on the new SL's ride comfort. It increases
the introduction rigidity - a parameter whose properties include
excellent road roar characteristics where NVH (noise, vibration,
harshness) qualities are concerned. Thanks to these constructive
measures relating to materials technology, the new luxury roadster
offers a chassis with outstanding comfort coupled with excellent driving
dynamics.
Like its predecessor, the new SL with adjustable
damping also has an anti-roll bar, which is mounted directly at the rear
axle and assembled together with the subframe, and serves to reduce the
connection points with the bodyshell.
The chassis has a virtually
neutral configuration, pleasing sporty drivers. In particular in the
range from 60 to 130 km/h it reacts with enormous agility, and therefore
facilitates a great deal of fun at the wheel on rural roads. In so
doing the SL allows lateral accelerations which are impressive even for a
sports car. Two different programs can be selected for the ESP®. The
control interventions from the more sportily tuned variant allow
side-slip angles during accelerated cornering - offering adept drivers
plenty of motoring pleasure. At the same time it can be driven more
easily and safely at higher speeds.
Electric Direct-Steer system for more driving dynamics
The
broad spread of suspension settings is supported by a new
electromechanical Direct-Steer system with speed-sensitive steering
power assistance and a variable steering ratio that changes according to
the steering angle. The ratio is very indirect when the steering is
centred, which ensures good straight-line stability and therefore a high
level of safety. In contrast to other variable steering systems, the
ratio of the Direct-Steer system decreases rapidly after a steering
angle of 5 degrees, becoming extremely direct from a steering angle of
just 100 degrees. Only relatively small steering movements are then
needed to make course corrections.
In contrast to the predecessor,
the Direct-Steer system optimises the ratio course. This enables the
new SL to shine with yet more agility, making cornering even more fun as
a result. At the same time, through the new ratio course the maximum
steering effort required when parking or turning is reduced by about 15
percent. This means that only 2.2 turns of the steering wheel from limit
to limit are now necessary.
This has the following effect in
practice: even at urban driving speeds, the driver needs to perform less
pronounced steering movements, making changes in direction possible
more rapidly and with less effort. The effect of the Direct-Steer system
is even more impressive on winding country roads, where only small
steering movements are sufficient to steer the vehicle. Even on tighter
bends, the driver's hands hardly need to change their grip on the
steering wheel. Rapid sequences of bends can be mastered safely and
precisely, and with enormous enjoyment.
Despite its remarkable
effect, the key component of the Direct-Steer system is a simple
steering rack. Its secret lies in the teeth cut into it. In the mid-area
these are slightly wave-shaped, with varying flank profiles. To both
sides the teeth are spaced at varying distances apart. The change in
steering ratio is therefore produced by purely mechanical means. With
this ingenious solution, Mercedes engineers have been able to dispense
with the elaborate actuators and complex sensor systems used by other
variable steering systems. The advantages of the Direct-Steer system
therefore include very low susceptibility to faults and low weight.
Moreover, the system always responds predictably and in the same way at
each steering angle, while other variable steering systems sometimes
require rapid adaptation by the driver in rapidly changing situations.
Instead
of hydraulically, as is the case with the familiar speed-sensitive
steering from Mercedes-Benz, the Direct-Steer system in the SL regulates
the steering force electrically. This is taken care of by an electric
motor - positioned axially parallel to the toothed rack - which
transfers its power to the ball screw as a rotary movement via a toothed
belt. The electric motor, drive unit, control unit and sensor system
are integrated in a compact unit.
The control unit evaluates a
large number of input variables in order to configure the steering
torque optimally in accordance with the situation in question. A torque
sensor determines the necessary assistance required at the steering-gear
input shaft. In so doing the electronics take into account, for
example, different vehicle axle loads. Due to the different engine
weights, the characteristic maps for six-cylinder and eight-cylinder
models are proof positive of the engineering artistry that lies behind
the system.
Further advantages of the electric steering:
- More
active response: the electronics support the steering return, meaning
that drivers hardly need to steer in order to return to the centre
position.
- Lower consumption: as output is only called up when
the driver is actually steering, the consumption falls by up to 0.3
l/100 km compared with the hydraulic Direct-Steer system.
- Active
parking: with the electromechanical Direct-Steer system the Automatic
Parking Control (APC) system can be offered in the Mercedes-Benz
SL-Class for the first time.
Assistance for critical road surface conditions
A
further assistance function has been realised in the new SL thanks to
the electromechanical steering power assistance - the Steer Assist
system: it can support stabilisation of the vehicle if the vehicle
brakes on a road surface with different friction (µ-split) on the left
and right, making it pull to one side. Drivers can find themselves
confronted with this situation, for example, on a road surface which is
covered with ice on one side. When braking, the vehicle then turns in
the direction of the high friction - referred to by experts as a yaw
impulse.
In this case the steering assistance system indicates to
the driver via the steering wheel that they should countersteer in the
correct direction in order to compensate for the yaw impulse caused by
the difference in friction - until the vehicle has stabilised again. In
order to do this the control unit evaluates the difference between the
ABS pressures on the right and left, giving an indication of different
road surface friction coefficients, and it also includes the ESP® data
which register oversteer in this sort of situation.
By way of
indication, the electric steering power assistance impresses a steering
torque which supports the driver's own reaction like a suggestion. This
steering torque, which causes the driver to steer correctly through a
light impulse, is hardly perceptible, and most of the time it is not
even noticed at all. Nevertheless the assistance function is effective.
However the steering assistance system merely provides an indication of
the direction in which the driver should steer in order to stabilise the
vehicle; it does not overrule the driver.
Brakes for sporty driving enjoyment
The
new SL has adopted the proven braking system with a dual-circuit brake
and the split of the two braking circuits between the front and rear
axle from the predecessor model. At the front all the variants are
equipped with newly developed 4-piston fixed-calibre brakes with an
aluminium monobloc design and perforated brake discs. 1-piston combined
floating brake callipers are fitted at the rear.
In order to be
able to provide the required output from the braking system, the heat
arising at the brakes must be removed as quickly as possible. This is
why special attention was given to aerodynamically favourable and highly
effective brake cooling. On the basis of different wind tunnel and road
tests, the aerodynamics engineers developed a system comprising several
components for targeted air ducting in the front axle area. A brake air
channel has been integrated into the front engine compartment trim in
order to guide the air over the front wheel spoiler in a targeted manner
and steer it onto a guide blade. The guide blade fixed to the front
suspension link diverts the air coming from the brake air channel over
the brake discs to the exterior. Together with a front matched wheel
spoiler, this has achieved effective cooling of the brakes. The newly
developed brake cover plates consist of steel at the front axle and
aluminium at the rear axle.
Electric parking brake with emergency braking function
As
a new feature in the SL, the electrically operated parking brake helps
in the design of a generous interior. Its switch is located in the
dashboard, under the rotary light switch. Pressing this engages the
electric parking brake, and pulling releases it. It is also released
automatically as soon as the engine is running, the transmission is in
the D or R position, the driver has a fastened seat belt and the
accelerator is operated.
Under normal circumstances, irrespective
of the duration of operating, the electric parking brake only closes the
responsible combined floating brake calliper at the rear axle fully and
for a sustained period when the vehicle is at a standstill or at speeds
below 4 km/h. Provision has also been made for an emergency braking
function: if the driver pressed the electric parking brake at a speed
higher than 4 km/h, the SL brakes to a safe stop with the aid of the
service brake. In this case, the emergency braking function is taken
care of by the hydraulic unit of the ESP®, with the brake lights also
lighting up.
The emergency braking is interrupted as soon as the control element is no longer kept depressed.
Torque Vectoring Brakes: ESP® helps with the steering
The
new SL includes the Torque Vectoring Brakes system as part of its
standard specification. This ensures an additional safety margin at the
physical limits, makes the roadster even more agile and therefore
enhances its sportiness. The system achieves this with targeted,
one-sided braking intervention by the Electronic Stability Program ESP®
at the inside rear wheel when cornering. If ESP® detects a tendency to
understeer, the Torque Vectoring Brakes generate a defined turning or
yawing moment around the vehicle's vertical axis within fractions of a
second. Thanks to the different torque distribution that results, the SL
turns into the bend under precise control without any loss of handling
dynamics. The advantage of this solution over complex mechanical
components such as an active steering rear axle, additional multi-disc
clutches or an active differential is that the Torque Vectoring Brakes
can be implemented without an increase in vehicle weight and therefore
no disadvantages in terms of fuel consumption.
Wheels and tyres - a broad base for the SL
As
part of its standard specification the SL350 is fitted with 17-inch
light-alloy wheels with 255/45 R17 tyres - options ranging up to 19-inch
wheels are available for selection on request. The SL500 is shod as
standard with 18-inch wheels with mixed-size tyres (8.5 J x 18 ET 35.5
with 255/40 R 18 tyres at the front, and 9.5 J x 18 ET 47.5 wheels with
285/35 R 18 tyres at the rear).
Safety: Top technology for the greatest possible safety
Mercedes-Benz
drivers are safer than drivers of other brands when out on the roads.
This is the result of an investigation carried out by Mercedes-Benz
accident research on the basis of official, anonymised random data
checks by Germany's Federal Statistical Office. It underlines the
efficacy of the comprehensive Mercedes-Benz safety philosophy. This
involves the experts not contenting themselves with achieving rating
targets, but working intensively on attaining a level of safety which
far exceeds the standards stipulated by the world's legislators. An
important measure of their work is not the laboratory or crash test
facility, but actual accident incidents. The results of the work carried
out by the safety experts at Mercedes-Benz is known as Real Life
Safety, a concept which is based on research into thousands of
accidents. Using this irrefutable evidence, for their holistic safety
concept they have developed or initiated most of the assistance systems
which today effectively support drivers and have been adopted by many of
the company's competitors.
"The new Mercedes-Benz SL sets new
standards for roadsters and can confidently be referred to as the safest
roadster in the world", remarks Professor Dr Rodolfo Schöneburg,
Director of Passive Safety at Mercedes-Benz. "The rigid aluminium
bodyshell offers superb preconditions for a stable occupant cell, as
well as for precisely defined deformation zones. This provides optimum
protection for the occupants in the event of an accident. But we do not
just think about those inside the vehicle - we also consider the other
road users, for instance through effective pedestrian protection
measures or assistance systems which also protect other motorists."
During
the development process for the new Mercedes-Benz SL-Class the
requirements of Euro NCAP and other rating institutes were taken into
account. The basis for this is a new light-alloy bodyshell which is
formed mainly by extruded sections and cast nodes made of aluminium. It
facilitates a light yet stable cell compound for a highly rigid occupant
cell. In conjunction with this the tail end and front are designed in
such a way that in the event of an accident they can absorb high forces
through deformation, thus considerably reducing the strain on the
occupants in a crash in accordance with the principle of the crumple
zone. The crash boxes behind the bumper trim and an exchangeable front
module ensure that the damage sustained during a front impact at up to
15 km/h can be limited.
Protection in the event of an overturn
The
occupants in the new SL enjoy good protection in the case of a
potential overturn, too. A-pillars in a steel/aluminium material mix and
two roll-over bars can protect the passenger compartment. Normally the
two roll-over bars are completely recessed, so they do not interrupt the
look of the elegant, luxury roadster's flowing lines. They are located
in two cartridges fixed to the bodyshell in the area behind the seat
backrests. If the system of crash sensors detects a potential overturn,
the airbag control unit emits a signal and the deployment mechanism is
activated. Two preloaded pressure springs per cartridge see to it that
the roll-over protection shoots to the support position in fractions of a
second.
Headbag and crash-responsive head restraints
The
restraint systems with two-stage driver and front passenger airbags
have been enhanced. A headbag provides generous lateral protection for
the head impact area. An additional thorax airbag in the seat backrest
can protect the upper body in the event of a side impact. The seat
belts, with inertia-reel tensioners and belt force limiters, serve to
highlight the high safety standards of Mercedes-Benz.
Another new
feature finding its way into the standard equipment of the SL comes in
the form of the NECK-PRO crash-responsive head restraints, developed by
Mercedes-Benz. They can support the driver's and passenger's head in the
event of a rear impact and reduce the risk of whiplash. Also fitted as
standard is automatic child seat recognition. The ISOFIX system is
available as an optional extra.
Protection for pedestrians
The
new Mercedes-Benz SL-Class Roadster uses the latest technology in the
area of pedestrian protection, too. A sensor system is able to register
an impact with a pedestrian and can ensure that the bonnet is
immediately raised by 85 mm in the rear section. This creates additional
space between the bonnet and the components in the engine compartment.
This in turn results in comparatively lower acceleration values for the
head of a pedestrian during the impact, thus reducing the overall risk
of injury.
The deformation properties of the bonnet have also been
specifically designed to meet the requirements concerning pedestrian
protection. It consists of aluminium with a homogenous reinforcement on
the inside of the bonnet and can therefore further reduce the loads in
case of an accident. The SL's "soft nose" also provides a large impact
area, whilst the foam density and geometry in the front bumper have been
optimised for reduced loads during leg impact with the pedestrian.
Only available from Mercedes-Benz - the anticipatory occupant protection system PRE-SAFE®
An
additional safety highlight is the standard-specification anticipatory
occupant protection system PRE-SAFE®, a system developed by
Mercedes-Benz and unique throughout the world. If it detects an acute
risk of an accident, it reflexively activates precautionary protective
measures for the vehicle occupants, also including the reversible,
electromotive belt tensioning function which ensures that the occupants
are better secured so that the seat belts and airbags are able to
perform their protective function to the full during an impact.
Mercedes-Benz developed PRE-SAFE® on the basis of research into actual
accidents, and is the only manufacturer in the world to offer such a
system.
Following an accident - optimally prepared
Mercedes-Benz's
holistic safety concept involves considering the phase after an
accident. This is why the new SL has numerous post-crash measures
incorporated on board which facilitate rapid assistance should the worst
come to the worst: depending on the type of accident and the impact
severity, the doors can be automatically unlocked, the interior lighting
activated and the side windows opened by 50 millimetres to provide
better ventilation in the interior. In addition to this, the steering
wheel can be slid upwards. The concept is completed by the Guidelines
for Rescue Services and the rescue cards which can be downloaded from
the internet free of charge and which can serve as a valuable support
for fire brigades.
ATTENTION ASSIST and ADAPTIVE BRAKE as standard
The
new SL also features a unique combination of driver assistance systems
which help to avoid accidents. These include the drowsiness detection
system ATTENTION ASSIST, for example. Thanks to this system, the
roadster develops a precise feeling for the level of attentiveness of
the driver and can provide an early warning of overtiredness.
Also
making up part of the standard equipment specification is the ADAPTIVE
BRAKE. It comprises ABS, the acceleration skid control system ASR and
also active yaw control (GMR). In addition, it features the following
functions:
- it supports the driver when moving off uphill, by preventing the vehicle from unintentionally rolling back;
- it
also keeps the vehicle stationary without having to keep the brakes
applied continuously - for example when waiting at traffic lights;
- as
soon as the driver abruptly steps off the accelerator, it brings the
brake pads into light contact with the brake discs as a precautionary
measure, so that the necessary braking pressure can be attained quicker
in the possible event of emergency braking;
- in wet conditions it applies light brake contact, without the driver even noticing, to dry the brake discs.
The
ADAPTIVE BRAKE works in conjunction with the equally adaptive brake
lights. In emergency braking situations, it warns vehicles behind with
rapidly flashing brake lights.
PRE-SAFE® Brake: autonomous partial and emergency braking in response to a serious risk of a rear-end collision
Available
as optional extras are the DISTRONIC PLUS proximity control as well as
the PRE-SAFE® Brake, already tried and tested in other Mercedes-Benz
models. The two systems together and can initiate emergency braking
automatically on detecting an acute risk of an accident.
In normal
driving conditions, the radar-based DISTRONIC PLUS proximity control
adjusts the distance to the vehicle in front automatically. If
necessary, it can apply the brakes, even bringing the SL Roadster to a
stop, and accelerate it again. This takes some of the strain off the
driver, particularly in bumper-to-bumper driving conditions. If the
distance starts to narrow too quickly, the system gives the driver
visual and acoustic warnings, thereby prompting the driver to take
action, at which point they are also supported by Brake Assist PLUS (BAS
PLUS).
If the systems detect the acute danger of a rear-end
collision and the driver fails to respond to visual and acoustic
warnings, the electronics activate the PRE-SAFE® Brake in preparation
for autonomous braking. This happens in two stages:
Around 1.6
seconds before the calculated impact point, the car initiates autonomous
partial braking with around 40 percent (approx. four m/s²) of the
maximum braking power, gives the driver an additional, haptic warning of
the impending impact and as a precaution activates the reversible
PRE-SAFE® occupant protection systems.
If the driver still fails
to react, the PRE-SAFE® Brake activates the maximum braking power around
0.6 seconds before the now unavoidable collision - this emergency
braking can greatly reduce the severity of the impact. The system
therefore acts like an "electronic crumple zone", offering the car
occupants even greater protection.
The PRE-SAFE® Brake is active
at speeds of between 30 and 200 km/h when moving vehicles are detected
in front of the car. The system also reacts if the car approaches a
stationary queue of traffic, providing the car's speed is below 70 km/h.
The
functionality of DISTRONIC PLUS has been enhanced even further. It now
reacts earlier to vehicles which cut in, and the car accelerates quicker
when changing lanes itself and where the overtaking lane is clear.
Thanks to the incorporation of information from digital maps (navigation
mode), automatic control has also been further refined.
Intelligent Light System - good vision at all times
The
Intelligent Light System also comes as part of the standard
specification. It offers variably controllable headlamps with five
different light functions which are adapted to suit driving and weather
situations commonly encountered. They switch themselves on depending on
the prevailing driving situation, offering the motorist a considerably
greater field of vision:
- The country mode distributes the
light from the low-beam headlamps in such a way that the left edge of
the carriageway is illuminated more brightly and across a larger area.
- The motorway mode switches on from a speed of 90 kilometres per hour and enlarges the field of vision by as much 60 percent.
- The
cornering light function is automatically activated when the main
headlamps are on and if the driver operates the indicator or turns the
steering wheel at a speed below 40 km/h. The low-beam headlamps and fog
lamps then illuminate the side area ahead of the vehicle to a range of
around 30 metres at an angle of up to 65 degrees.
- The active light function improves illumination of the road on bends by up to 90 percent.
- The
enhanced fog light function works by pivoting the left-hand bi-xenon
headlamp outwards by several degrees and lowering its beam. This
provides brighter illumination of the inner half of the road.
Adaptive
Highbeam Assist is also on board as part of the standard specification:
when vehicles are detected ahead of or approaching the vehicle, this
system automatically dips the beams and adjusts the range of the
headlamps according to the distance.
The assistance systems spring into action
Those
wanting to can choose to extend the potpourri of assistance systems in
the new SL even further. They provide extra doses of both safety and
comfort. As an option Mercedes-Benz can equip the roadster with the
following helpful features:
- Speed Limit Assist: it is able to
detect speed limit signs using a camera on the inside of the windscreen
and indicate the respective detected speed limit on a display in the
instrument cluster and in COMAND. (Standard-fit in conjunction with
COMAND online).
- Active Blind Spot Assist: it warns the driver
when changing lanes if a risk of collision is detected due to another
vehicle in the neighbouring lane being in the blind spot of the exterior
mirror. If the driver ignores the warning and nevertheless initiates
the lane-changing manoeuvre, the Active Blind Spot Assist intervenes. A
brake actuation counteracts the collision course. (Part of the driver
assistance package with DISTRONIC PLUS including the PRE-SAFE® Brake and
Active Lane Keeping Assist).
- Active Lane Keeping Assist: this
system kicks into action if the Mercedes-Benz vehicle inadvertently
drifts over a solid line to the right or left of a lane. In such a case,
a warning sign in the instrument cluster and vibrations in the steering
wheel warn the driver. If the driver does not heed the warning in the
case of a solid line, Active Lane Keeping Assist can use the ESP® to
brake the opposite wheels and thereby prevent the vehicle from crossing
the solid line. (Also part of the driver assistance package - please see
above).
Hands off the steering wheel when parking
Active
Parking Assist will answer the prayers of many drivers in the
chronically congested traffic areas of Europe: the SL can not only
detect parking spaces, but also help with the parking itself. This is
made possible thanks to a combination of the new electromechanical
Direct-Steer system (please see the chapter on the chassis and
suspension) and a series of ultrasonic sensors. This convenience system
features the following functions:
- Measurement of potential
parking spaces lengthwise to the direction of travel - even in slightly
curved bends - up to a drive-by speed of 30 km/h. The parking spaces
must be at least one metre longer than the vehicle.
- Calculation of a suitable parking manoeuvre in order to park the vehicle parallel to the kerb.
- Automatic steering in order to perform this parking manoeuvre.
- Automatic
steering in order to exit the parking space. This is only possible if
the parking space was entered using Active Parking Assist.
Two
ultrasonic sensors take care of the search for suitable parking spaces
lengthwise in the direction of travel. They are integrated in the front
bumper, on the left and right. If the speed falls below 30 km/h, a "P"
symbol in the instrument cluster signals to the driver that the active
search for a parking place has been started automatically. If the system
has found a potential parking space, an arrow indicates this alongside
the "P" symbol. As standard, the arrow shows parking spaces on the
passenger side. If the indicator on the driver's side has been
activated, it shows potential parking spaces on the driver's side.
It
is up to the driver to assess whether the free area designated by the
system is indeed actually a parking space. Even during the parking
procedure the responsibility remains with the driver. They activate the
accelerator and brake pedals during parking. The Active Parking Assist
takes care of the steering and for orientation it uses the two front
ultrasonic sensors as well as four further sensors in the rear bumper.
During parking, the roadster must not move faster than 10 km/h. The
automatic parking manoeuvre is configured for a maximum of five turns
(backwards-forwards-backwards-forwards-backwards). Once the vehicle is
standing correctly in the automatically selected parking space, the
system aligns the wheels.
The Active Parking Assist switches
itself off as soon as the driver intervenes in the automatic turning of
the steering wheel, if the system is turned off via the PTS button
(Parktronic sensor), both if the driver's seat belt buckle or the
driver's door is open, or if there is a system error. Nevertheless the
familiar PARKTRONIC function remains available without any restrictions.
Infotainment: The fully integral sound of tomorrow
As
a rule, those gifted with a sensitive sense of hearing cannot expect
much listening enjoyment in a roadster. Even good car radios and CD
players are disappointing under these arduous acoustic conditions.
Instead, in open-top cars, the music flies away with the wind; it frays
and breaks up in all directions without its acoustic base - passengers
generally have to be satisfied with a woolly "sound carpet", or close
the roof. Open-air pleasure and musical enjoyment could hardly be
expected in a roadster. A great part of the blame for this lies with the
location of the bass loudspeakers in the doors or under a seat.
Mercedes-Benz now presents a solution to this conflict: the unique
Frontbass system, which at last creates the conditions for a concert
hall ambience in a roadster too. In the new SL, the Frontbass system is
celebrating its world premiere.
Crisp bass sound from the footwell
The
principle sounds simple: Instead of being placed in the doors in the
usual way, in the new SL generation the bass loudspeakers are installed
in the footwell in front of the driver and passenger. This is not
possible with traditional vehicle shell structures, but the two front
longitudinal members in the front aluminium skeleton of the new
Mercedes-Benz SL-Class provide the resonance space needed for this
arrangement. The loudspeakers are fitted directly in two openings in the
firewall on either side of the footwell. Cavities in the longitudinal
members behind the speakers act as resonating chambers. The outstanding
inherent rigidity of these structural components results in
ultra-precise low notes with extremely little distortion, right up to
very high signal levels. In order words, the new SL features clear,
crisp bass sounds with a high dynamic range as part of its standard
equipment.
The position of these two independent closed woofers in
the footwell permits the creation of ideal acoustic conditions, because
the firewall, the vehicle floor and the underside of the dashboard form
a sort of funnel that focuses and concentrates the sound - a better
sound performance is the result. The acoustic effectiveness improves
significantly. The formula 'low energy plus lots of sound volume' saves
energy on top of it all. This way, the Frontbass system also contributes
towards a CO2 reduction.
Precise, brilliant sound
With
the new Frontbass system, Mercedes-Benz is not only revolutionising
in-car bass sound reproduction - and in particular aboard an open-top
roadster - it is also creating the conditions for exceptional listening
enjoyment. Since the bass loudspeakers now do not need to be installed
in the doors, the disruptive acoustic vibrations typical of this
configuration no longer occur. In addition to this, the sound experts
have placed the mid-range and high-tone loudspeakers in the doors, the
dashboard and in the vehicle rear optimally close to the beltline and
thus almost at the same height as the SL occupants' ears. This way they
produce a precise, brilliant sound quality. The experts speak of an
exact stage reproduction with precise instrument representation and an
equally precise spatial graduation.
Even the standard entry-level
Frontbass system creates a pronounced encircling sound feel and an
emotive sound experience, independently of whether the vehicle roof is
open or closed. As Norbert Niemczyk, responsible for the new Frontbass
system at Mercedes-Benz, explains: "Our objective was not mere sound
volume - although in this respect, too, the system performs amazingly -
but a clear sound instead, one that never becomes "mushy". We have
achieved this. All those who experienced the sound with the Frontbass
system for the first time got out of the car with a big smile on their
face - in-house we call that the Frontbass smile."
Friendly to the surroundings: focused sound
Acoustic
enjoyment of the highest level is part of the programme in the new
Mercedes SL both with a closed and with an open top. As the Frontbass
system focuses the sound, the powerful sound is concentrated on the
vehicle occupants - the surroundings are significantly less disturbed
than is the case with conventional sound systems. Apart from this, the
amplifier automatically controls the loudspeakers in a different manner
depending on whether the passenger compartment is closed or open,
according to the acoustic conditions, in order to create the best
possible sound.
Frontbass is always on board
The
Frontbass concept is the standard basis in every version of the new
Mercedes-Benz SL. In the entry-level variant it is coupled with an
amplifier that is integrated in the COMAND head unit with an output of
4x25 watts, two Frontbass loudspeakers with a diameter of 217 mm, two
two-way systems for high and mid-range tones in the doors and two more
mid-range speakers in the rear.
The optionally available Harman
Kardon® Logic 7® surround sound system in conjunction with the Frontbass
concept offers a further enhancement and a musical delicacy of concert
hall quality. The heart of the matter is a Class D amplifier with a
total output of 600 W and a digital signal processor (DSP) for ten audio
channels. The two Frontbass loudspeakers and six two-way systems
provide an even more precise and better defined sound reproduction
quality.
Finally, the ultimate in high-calibre pleasure for the
eyes and ears comes courtesy of the high-end Bang&Olufsen BeoSound
AMG sound system, also available as an optional extra. The Class D ICE
power amplifier and the Class D DSP amplifier with a total output of 900
watts actively control the twelve high-end loudspeakers via separate
channels, thus ensuring the hallmark B&O crystal-clear sound
reproduction. Via the B&O-specific True Image menu various sound
settings such as the true-to-life studio-like reproduction in reference
mode or a space-optimised reproduction in surround mode can be selected -
and the sound fields can be precisely adjusted to the seats being used.
In addition to this, the automatic volume regulation function Vehicle
Noise Compensation automatically adjusts in accordance with the speed
and the exterior and interior noises measured with a microphone,
facilitating exclusive audiophile high-end sound at all times,
irrespective of external influencing factors such as noises caused by
the engine or the airflow.
High-end music enjoyment with the DVD "Mercedes-Benz Signature Sound"
So
that SL drivers can fully appreciate and enjoy the Surround Sound and
the unique Front Bass system, Mercedes-Benz has edited an exclusive,
limited music DVD with the title "Mercedes-Benz Signature Sound". The
name stands for the unique signature sound of the musical pieces. It
comprises 15 well-known pop/rock songs and 10 masterworks of classical
music, re-worked and fine-tuned to the exceptional acoustic conditions
of the roadster by Grammy-winning experts at one of the best sound
studios in the world. Its transparent, crystal-clear sound provides a
musical experience of the highest level. The DVD "Mercedes-Benz
Signature Sound" can be found in every new SL Roadster that has been
ordered with a Surround Sound system.
Bodyshell tuned to Frontbass
In
order to realise the Frontbass concept, the sound specialists worked in
close cooperation with the bodyshell designers right from the very
first planning stage. A small welcome side effect is that since the
Frontbass concept made the loudspeakers in the doors superfluous, the
designers were able to use the space made free in the doors for
additional stowage compartments.
