Auto Car Magazine: New Mercedes-Benz CL-Class in Depth

1: Overview (I)

Overview (I)

In autumn 2006 Mercedes-Benz is launching the culmination of more than 50 years of coupé tradition with the new CL-Class. The new two-door model combines peerless exclusivity and charismatic design with trailblazing technology which no other car brand is able to offer. The luxury coupé enters new dimensions in vehicle safety with PRE-SAFE® Brake, a unique system which automatically brakes the Coupé when a rear-end collision threatens. Standard equipment also includes Mercedes innovations such as an active ABC suspension (Active Body Control), the Intelligent Light System with five lighting functions and the anticipatory occupant protection system PRE-SAFE®. There is a choice of two powerful engines with eight or twelve cylinders. These generate significantly more output and torque, while exhibiting an exemplary smoothness which lives up to the Mercedes heritage of superb motoring refinement.

The large Mercedes Coupés have been the epitome of elegance and exclusivity in automotive engineering for many decades. They set standards in design and equipment, combining outstanding safety with the greatest comfort and a superior driving experience. In short, Mercedes Coupés are dream cars of a very special kind - automotive classics.

The new CL-Class is yet another masterpiece by Mercedes-Benz. Just as this luxury coupé points the way into the future with its innovative technology, its design is a protagonist for a new aesthetic appearance - a new Mercedes style. This is characterised by an interplay between taut, striking lines and large, tranquil surfaces. This design idiom lends the Coupé a very special presence, underlining the unruffled calm and strength of its unique character.

Familiar Mercedes characteristics are reinterpreted and incorporated into the design concept to form a harmonious composition of tradition and modernity. Examples are the typical Mercedes radiator grille with its wide chrome louvres and the design of the C-pillar. This unique, slightly downwards-tapering pillar configuration is a typical feature of the large coupés whose roots go right back to the 1950s: in 1956 the Model 220 S/SE Coupé (model series W 180/W 128) first captured attention with such a C-pillar design, and a few years later it was further perfected in the succeeding model, the 220 SE Coupé (W 111/112).

Other design features which were already acclaimed at that time have also been reinterpreted in the new CL-Class, keeping alive the great coupé tradition of the Mercedes-Benz brand: for example the fully retractable side windows, whose continuous aperture is not interrupted by a B-pillar, and the large, curving panoramic rear windscreen. In the early years this was a typical styling feature of Mercedes Coupés, and in its stylistically evolved form it is just as appealing as in the 220 SE Coupé of 1961.

Interior: appointments for even the most discerning

The same elegance is found in the interior: the large window aperture draws the eye to the stylish dashboard, exquisite wood trim and soft leather upholstery. It is immediately apparent that everything in the interior is designed for comfort and relaxation. The atmosphere is reminiscent of an exclusive club: take a seat and enjoy. There is a choice of five stylish colour combinations, while automatic climate control, COMAND with a car radio and CD/DVD player and a glass sliding sunroof are other standard equipment items which contribute to the uniquely comfortable driving experience.

In the top-of-the-line model CL 600, an interior in PASSION leather, specially selected poplar wood trim and an Alcantara roof liner with quilted seams contribute to a luxurious, first-class atmosphere which is also echoed by designo seats, chromed door sill panels and deep-pile floor mats with leather edging. The standard specification also includes dynamic multicontour seats with massage function and seat ventilation, the hard-disc navigation system COMAND APS, the LOGIC7® surround sound system with DVD changer and the KEYLESS-GO access and drive authorisation system.

Compared with the outgoing model, the new Mercedes-Benz top-of-the-range coupé has grown slightly in every dimension. 5065 millimetres long, 1871 millimetres wide and 1418 millimetres high, the body is 75 millimetres longer, 14 millimetres wider and 20 millimetres higher than before, providing even more comfort and space on all four seats. The boot capacity has been increased by 40 litres to 490 litres (VDA measuring method).

Control system: fewer switches for more functions

A newly developed control system, which has already been successfully imple-mented in the S Class worldwide, refines driver-vehicle interaction even further. Its main advantage is that it provides convenient, rapid access to frequently used functions such as the radio, DVD player, car phone or navigation system. Depending on the driver's own preference, these systems can be controlled using switches in the centre console, pressing a button on the multifunction steering wheel or using the COMAND controller on the centre console. This central con-trol element is linked to the large, pivoting COMAND colour display next to the instrument cluster, providing access to the user-friendly main and sub-menus that activate the various functions.

The standard automatic climate control with four independently adjustable temperature zones is also integrated into the new control system. The driver and front passenger can select temperature, air distribution and other settings either using the COMAND controller and menu-based control, or by means of an attractively styled switch array beneath the air vents. The COMAND system allows other individual climate settings to be adjusted, such as air distribution and the footwell temperature.

The newly developed integral seats in the CL-Class provide maximum individual seating comfort. "Integral" means that all components of the seat belt system are incorporated directly into the seat; hence the seats form an important component in the occupant protection system. The standard specification already provides electric adjustment of the longitudinal setting, inclination of the seat and backrest, seat height, head restraint and length of the front seat cushions. Pneumatic lumbar supports allow the driver and front passenger to adjust the backrest contour to suit their build and consequently reduce the strain on the back muscles.

Optional extras include luxury seats with active ventilation (standard in the CL 600) that provide even more individual comfort, along with the further enhanced multicontour seats with nine air cushions, and dynamic multicontour seats with massage function (standard in the CL 600).

The driver and front passenger seats with multicontour function have been awarded the AGR ("healthy back campaign") seal of approval.

Active Body Control: superb combination of dynamism and comfort

The standard specification in the new Mercedes Coupé features technological innovations that no other manufacturer can match anywhere in the world. First and foremost is the Active Body Control (ABC) suspension system, which in its latest, even more sophisticated guise delivers unprecedented handling dynamics while offering an equally appreciable improvement in ride comfort. Based on sensor signals and using specially designed hydraulic cylinders at the axles, ABC all but entirely eliminates the customary pitch and roll of the body that occur when moving off, cornering and braking. ABC responds with split-second speed to ensure the body damping is adjusted instantly to any situation. At speeds above 60 km/h, ABC lowers the body by up to ten millimetres in the "Sport" programme to reduce drag and improve handling stability.

Another special feature of Active Body Control is its variable distribution of body roll between the front and rear axles according to vehicle speed, which combines agile handling with outstanding stability.

Intelligent Light System: five lighting functions to match driving and weather conditions

The Intelligent Light System, which makes driving even safer in the dark, is equally unique. Together with bi-xenon headlamps it forms part of the standard specification for the new CL-Class and provides five different lighting functions that are activated to match driving and weather conditions: the new country road mode illuminates the driver's-side edge of the road more widely and brightly than the existing low-beam headlamps.

Motorway mode, which comes on automatically when driving above 90 km/h, delivers a uniform cone of light that illuminates the entire road width. In the centre of this cone the driver is able to see around 50 metres further. The enhanced fog lamps are also new, which Mercedes-Benz uses to provide better orientation in adverse weather conditions. The active light function and cornering light function are also part of the standard-fit Intelligent Light System on the CL-Class.

2: Overview (II)

Overview (II)

PRE-SAFE®: automatic partial braking before an impending accident

Mercedes-Benz is the world's first car brand to develop an anticipatory occupant protection system that recognises a potential accident situation in its early stages and initiates appropriate occupant protection measures: PRE-SAFE® is standard in the new CL-Class. During emergency braking or when skidding is imminent, the system moves the passenger seat into a more favourable position so that seat belts and airbags have maximum effect on impact. It also inflates air cushions in the dynamic multicontour seats (standard in the CL 600), which envelop and support the driver and front passenger. PRE-SAFE® also closes the side windows and the sunroof in critical situations where high lateral dynamics are generated.

Mercedes-Benz has just made this multi-award-winning anticipatory protection system even better in the CL-Class with the newly developed PRE-SAFE® Brake system. This operates in tandem with Brake Assist PLUS (BAS PLUS), which warns the driver of an imminent rear-end collision via visual and audible signals and automatically calculates the required braking pressure to prevent an accident. This braking-power support is available as soon as the brake pedal is operated. If the driver does not react to the BAS PLUS warnings, the PRE-SAFE® Brake system triggers automatic partial braking where an accident is imminent and slows the CL Class down using around 40 percent of the total braking power.

The automatic partial braking provides the driver with another clear warning to act. If the driver then immediately applies the brakes, the maximum braking force is available and the accident can - depending on the situation - be averted at the last moment. If an accident is unavoidable, the PRE-SAFE® Brake system reduces the impact severity and, in turn, the risk of injury to the vehicle occupants.

As with Brake Assist PLUS, the new PRE-SAFE® Brake system also utilises state-of-the-art radar technology to scan the situation in front of the car and detect a potential accident. Two short-range radar sensors with a range of 30 metres and a scanning angle of 80° are located behind the front bumper fascia on the CL-Class. The additional long-range radar in the radiator grille has a range of 150 metres.

Mercedes-Benz also offers BAS PLUS and the PRE-SAFE® Brake system in conjunction with the optional DISTRONIC PLUS proximity cruise control.

Driver-support systems: radar sensors make parking child’s play

The newly developed parking guidance system (optional extra, available from December 2006) also works on the basis of radar technology: the sensors measure the length of a parking space when driving past and show on the cockpit display whether there is sufficient space to park. Once reverse gear is engaged, the display includes a symbolic representation of the parking manoeuvre; guide lines show the required steering angle and indicate the path into the parking space. Night view assist with infrared headlamps, a reversing camera, voice control for car radio, a DVD changer and navigation as well as a tyre pressure monitoring system are other optional Mercedes assistance systems for increased handling safety and comfort.

Engines: eight and twelve-cylinder powerplants with noticeably more power

The new luxury Coupé is ready for any challenge on motorways and rural roads thanks to the most powerful Mercedes engines to date. The eight-cylinder powerplant in the CL 500 delivers 285 kW/388 hp and generates a maximum torque of 530 Newton metres from 2800 rpm. As such the newly developed engine outperforms the existing V8 unit by 26 percent in terms of output and 15 percent when it comes to torque. Equipped with four-valve technology, variably adjustable shifting camshafts, a two-stage intake module and tumble flaps in the intake ducts, the new V8 is among the most advanced and powerful engines in its displacement class. The CL 500 accelerates from zero to 100 km/h in just 5.4 seconds (previous model: 6.3 seconds).

An ultra-modern biturbo twelve-cylinder engine under the bonnet of the new CL 600 generates its impressive power. Mercedes engineers have enhanced numerous details of the power unit and, compared to the predecessor model, have increased output by 12 kW/17 hp to 380 kW/517 hp. The maximum torque, already on tap from 1900 rpm, has been improved further by 30 Newton metres to 830 Newton metres and remains constant up to 3500 rpm. The new CL 600 accelerates from 0 to 100 km/h in just 4.6 seconds (previous model: 4.8 seconds). And despite the significant performance boost the V12 engine consumes 0.4 litres less fuel than the previous CL 600 per 100 kilometres.

Mercedes-Benz has combined the standard-fit automatic transmission with the new DIRECT SELECT gearshift: the driver can select the transmission settings “P”, “N”, “R” and “D” by nudging a lever on the steering column. Operating commands are transmitted electronically by wire.

Tradition: seven generations of the Mercedes-Benz Coupé

The new CL-Class ushers in the seventh generation of the large Mercedes Coupés. The two-door model replaces the world-beating outgoing model, which joins the ranks of the best-selling luxury coupés with around 46,800 units sold. The history of the large Mercedes Coupés stretches back to 1952 when Mercedes Benz launched the legendary 300 S Coupé - a “car for the world's elite” was the verdict of the motoring press in its day. In 1956 it was followed by the 220 S Coupé as part of the W 180 model series, which fired the public’s imagination with its unitised “Pontoon” body in particular. And in 1961 the220 SEb Coupé (W 111 model series) took up the baton with its stylish elongated body.

In 1981 the SEC Coupés from the C 126 model series were based on the then S Class and remained in the Mercedes-Benz line-up for 10 years with over 74,000 units produced. In 1992 the Geneva Motor Show was host to the launch of the successor model (C 140 model series), powered for the first time by a 290 kW/394 hp twelve-cylinder engine. The predecessor to the new CL-Class Coupé celebrated its world premiere in March 1999, setting new standards with leading edge Mercedes innovations such as the Active Body Control (ABC) suspension system and bi-xenon headlamps.

Mercedes-Benz has built over 178,000 luxury coupés since 1952.

3: At a Glance

7G-TRONIC seven-speed automatic transmission: The world’s only automatic car transmission with seven gears works in tandem with DIRECT SELECT, the electronic control system.	Standard for CL 500
Active Body Control: The active suspension is even more sophisticated than before, delivering superb comfort and dynamic handling.	Standard
Active light function: The headlamps in the Intelligent Light System follow the driver’s steering movements.	Standard
Adaptive brake lights: Flashing brake lights warn drivers behind in emergency braking situations.	Standard
ADAPTIVE BRAKE: The newly developed braking system provides driver-assistance functions to make hill-starts and driving in heavy traffic easier.	Standard
Adaptive front airbags: The front airbags are deployed in two stages depending on impact severity.	Standard
Automatic climate control: The newly developed system operates with four temperatures zones and provides numerous settings for individual climate control.	Standard
Belt force limiters: This technology reduces the belt forces acting on the occupants during a crash.	Standard for all seats
Belt tensioners: Any slack in the seat belt is instantly taken up in a crash.	Standard for all seats
Bi-xenon headlamps: Gas-discharge lamps for main and low beam improve safety when driving at night.	Standard
Brake Assist PLUS: The radar-based system identifies critical situations involving a rear-end collision and calculates the required braking power to prevent a possible accident. The optimum braking pressure is available immediately when braking.	Optional in conjunction with DISTRONIC PLUS
Child seat recognition: A transponder system automatically detects whether a rear-facing child seat is installed and deactivates the front passenger airbag if this is the case.	Standard
COMAND APS: The navigation system data is stored on a hard disc - making it even faster to plan the route.	Optional, standard for CL 600
COMAND: This system integrates the radio, DVD player, navigation and telephone operation.	Standard
Cornering light function: This lighting function in the Intelligent Light System provides enhanced safety at junctions or when driving slowly around tight bends.	Standard
Country road mode: This function in the Intelligent Light System replaces the low-beam headlamps and illuminates the driver’s-side edge of the road more brightly and widely.	Standard
DISTRONIC PLUS: The enhanced proximity control brakes the CL-Class in stop-and-go traffic down to a standstill.	Optional
Dynamic multicontour seat: Thanks to new piezo valves the seat responds even faster to steering movements and provides superb lateral support.	Optional, standard for CL 600
Electric parking brake: Thanks to the electric motor, the parking brake can be activated comfortably and conveniently.	Standard
ESP^®: This safety system can reduce the risk of skidding when cornering and alerts the driver to any loss of tyre pressure.	Standard
Extended fog lamps: This function in the Intelligent Light System means the outer headlamp swivels outwards to provide better illumination of the edge of the road.	Standard
Headlamp Assist: A sensor on the windscreen detects low light conditions and automatically switches on the vehicle lights.	Standard
Integral seats: The seat belt system along with the pneumatic lumbar supports are integrated into the front seats.	Standard
Intelligent Light System: The new headlamp technology provides five lighting functions that are activated to match the driving and weather conditions (see also cornering light function, country road mode, motorway mode, active light function and enhanced fog lamps).	Standard
KEYLESS-GO: The doors and tailgate can be opened without using a key.	Optional, standard for CL 600
LINGUATRONIC: The voice control system can be used to operate the radio, navigation system and telephone.	Optional, standard for CL 600
Massage function: Seven air chambers in the backrest, which fill and empty alternately, massage the back muscles.	Optional in conjunction with dynamic multicontour seat, standard for CL 600
Memory function: Three different settings can be saved for the driver and front passenger seat respectively. The settings for steering wheel and exterior mirrors are also saved.	Standard
Motorway mode: From a speed of 90 km/h the entire width of the road is illuminated and the driver’s range of vision is increased by around 50 metres.	Standard
Multicontour seat: Air cushions enable the seat contours to be individually adjusted to suit the occupant’s body.	Optional, standard for CL 600
Multifunction steering wheel: The radio, telephone, navigation system and other units can be operated from the steering wheel.	Standard
Night view assist: Infrared headlamps and a display in the cockpit significantly increase the driver’s range of vision in the dark.	Optional
Paintwork: Nano-technology makes the standard metallic paint finish more scratch-resistant and ensures a higher sheen.	Standard
Parking Assist system: The system assists with parking and warns if there is a risk of a collision when reversing.	Optional in conjunction with DISTRONIC PLUS
Parking guidance system: Radar sensors measure the size of a parking space when driving past and a cockpit display helps the driver park inch-perfect.	Optional
PARKTRONIC: Ultrasound sensors assist the driver when parking.	Standard
PRE-SAFE® brakes: The system initiates automatic partial braking when a rear-end collision appears imminent.	Optional in conjunction with DISTRONIC PLUS
PRE-SAFE®: Anticipatory occupant protection measures are taken before an impending collision.	Standard
Reversing camera: The area behind the car can be seen on the display to aid reversing.	Optional
Seat ventilation: The further improved technology is based on six mini fans in the seat cushion and backrest.	Optional, standard for CL 600
Sidebags: The side-mounted airbags (front and rear) reduce the risk of injury in a lateral collision.	Standard
Sound system: Multi-channel system with innovative digital technology provides surround sound on every seat.	Optional, standard for CL 600
TV reception: The tuner receives both terrestrial digital TV (DVB-T) and analogue programmes.	Optional
Windowbags: The large curtain-type airbags drop down from the A-pillar to the C-pillar in the event of a side impact.	Standard

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4: Design

Design

Another example of a new Mercedes design idiom

Interplay between taut lines and calm, elegantly contoured surfaces

Modern interpretation of traditional coupé characteristics

Serene luxury and the highest quality in the interior

Breaking new ground and setting trends – that is the goal of Mercedes design development. It reflects the principle of Mercedes-Benz never to stand still, but always to think further and stay ahead.

The new CL-Class is a prime example of this philosophy: just as this luxury coupé with its innovative technology points the way into the future, its design joins the S-Class in being a protagonist for a new aesthetic appearance – a new Mercedes style. It is based on the principles of modern purism, i.e. on a clear, unostentatious design idiom with an interplay between striking lines and calm surfaces. This lends the Coupé a very special presence, underlining the unruffled calm and strength of its unique character.

Yet design progress at Mercedes-Benz also always means creating a link with the past to emphasise the heritage of passenger cars bearing the Mercedes star. This is done by including familiar Mercedes characteristics, which are reinterpreted and incorporated into the design concept to form an exciting composition of progress and tradition. One example is the front end, where the louvred radiator grille with its central Mercedes star unmistakably confirms the car’s identity. The designers in Sindelfingen have positioned this traditional feature of sporty Mercedes models at a steeper angle than in the preceding series, also equipping it with wide, highly expressive chrome louvres. This contributes to the extremely powerful and self-assured appearance of the new CL-Class, which is further reinforced by the more pronounced arrow-shape of the entire front end.

The headlamps are highlights in two respects. In technical terms, with the Intelligent Light System, they represent the very best available anywhere, while in styling terms they are one of the most striking features of this Mercedes Coupé and lend a special touch to its overall appearance. The bi-xenon module and an additional high-beam headlamp are enclosed in highly polished cylinders reminiscent of expensive camera lenses, suggesting attributes such as precision, high value and high technology.

Viewed from the front, the transparent lenses of the headlamps form a single unit with the radiator grille which impressively emphasises the visual width of the vehicle body. The side view shows that the headlamps are perfectly blended into the wings, creating a flowing transition from the front end to the flanks. As a result the entire front section appears to have been moulded from a single piece. The indicator strip horizontally arranged in the lower headlamp section harmoniously follows the sweeping contours of the front bumper, which likewise extends well into the flanks to frame the lighting units.

Wings: expressive anatomy

The eye is directed towards the wheel arches and wings, where new highlights are to be found in the body language of the Mercedes Coupé. The stylishly contoured wings enable the two-door car to flex its muscles discreetly yet purposefully. Intentionally rather taut and physical, the pronounced, rounded contours of the wings arch over the wheels and symbolise the power residing beneath the elegant outer skin of the CL-Class.

Athleticism coupled with confidence, power with prestige: the body "anatomy" created by the designers ensures that from every angle, the two-door Coupé has a wide, self-assured presence on the road. The interplay between lines and surfaces is equally expressive, as the soft, rounded forms of the bumper and wings contrast with the taut outside lines of the bonnet – visual demarcation lines which lend additional contours to the front end and mark a transition to the large, calm surface of the bonnet itself.

The sharp outer lines of the bonnet have another importance for the design concept, as they form a gentle, flowing transition to the A-pillars, elegantly connecting the front end to the passenger compartment.

Flanks: intriguing lines

One of the distinguishing aspects of the modern purism inherent to the new Mercedes style is the interplay between taut lines and elegantly contoured, calm surfaces. A coupé like the CL-Class particularly lends itself to this design theme: two lines drawn at different heights give the flanks their formal structure, subdivide the large areas and act as major styling features to define the dignified appearance of the car’s stretched silhouette. These lines have a special visual impact, attract attention and appeal to the emotions of the observer.

The designers refer to one of them as the character line; this structures the upper third of the vehicle flanks, also providing an appealing refractive edge between the concave and convex door surfaces. In this way the design uses light and shade very effectively, ensuring a variety of contrasts when viewed from any perspective. At the rear this character line precisely meets the rear light cluster, which extends well into the flanks and continues its course gently downwards.

The shoulder line lies above the character line, emerging organically from the front wings and extending to the rear via the bottom line of the windows. This muscular shoulder supports the slim, almost filigree A-pillar which in turn gives rise to the third characteristic line of the Mercedes Coupé, namely the roofline. This spans the body in a light but pronounced curve, defines the line of the C-pillar and gently dips down with it into the rear end of the Mercedes Coupé. A fine chrome strip on the upper frame of the side windows follows the roofline and emphasises its curved contour.

C-pillar: living tradition

The design of the C-pillar demonstrates how Mercedes designers are at pains to combine tradition with modernity. This unique, slightly tapering pillar configuration is a typical coupé feature whose roots go right back to the 1950s: in 1956 the Model 220 S/SE Coupé (model series W 180/W 128) first captured attention with such a C-pillar design, and a few years later it was further perfected in the succeeding model, the 220 SE Coupé (W 111/112).

Rear end: a beautiful back

The masterly blend of surfaces and lines which characterises the flanks of the luxury Coupé is continued at the rear. The eye is immediately drawn to the large, panoramic rear windscreen, which makes for a rounded, exquisitely modelled rear end together with the soft lines of the C-pillar and the boot lid. The rear light clusters extending well into the sides of the rear end are intended to shorten the visual impression of the rear and create sporty, muscular proportions. Both rear light clusters act as a continuation of the character lines along the flanks, cleverly extend these by means of a colour division in the lens and thereby act together with the V-shaped joins of the boot lid to produce the typical Mercedes rear-end design.

The rear-end design makes a statement on two levels: by virtue of its muscular proportions it confirms the sporty attributes of the new CL Coupé, which are also emphasised by the horizontally structured rear bumper and the two prominent exhaust tailpipes. On the other hand the beautifully sculptured rear light clusters, the wide chrome strip on the boot lid and other details provide a touch of elegance. They dominate the overall visual impression and thereby reflect the true character of the Mercedes Coupé.

Interior: welcome to the club

There is no doubt that the sweeping flanks are the most appealing visual aspects of the new CL-Class – especially when the windows are open to afford an unimpeded view of the interior. No window frame or B-pillar interrupts this continuous aperture. This is where the fascination of a coupé begins, blending the exterior and interior into a single unit for the observer.

The large window aperture invites the eye into the interior, where it is drawn to the attractive contours of the dashboard. It immediately becomes obvious that everything in the interior is designed for comfort and relaxation. The atmosphere is like that of an exclusive club: take a seat and indulge your senses of vision, smell and touch in pleasing forms, fine materials, tasteful colour combinations and the unmistakable attention to detail for which Mercedes designers are known.

This first impression – seeing and feeling – is without doubt always the most important when it comes to emotional appeal. Nonetheless a car must demonstrate its qualities on a daily basis, both on short trips and on long journeys. It must therefore possess further attributes if the atmosphere of wellbeing created by its designers is to endure – good ergonomics, comfort and reliable technology to relieve the driver’s workload. In these areas too the CL-Class sets a new standard among luxury coupés: spaciousness, freedom of movement, noise comfort, seating quality, operating comfort and typical Mercedes innovations make the driving experience perfect - in every respect.

The interior design reflects these strengths. In the area of the dashboard and centre console it has a vertically arranged architecture which already proved highly successful in the preceding series. It is in line with current design concepts for sporty vehicles and shows that in addition to elegance and exclusivity, the CL-Class is certainly no slouch in the performance stakes. Due to the principle of vertically oriented design, the centre console and tunnel trim form a single stylistic and functional unit which extends right back into the rear, carries important control features such as the COMAND controller and provides a great deal of stowage space. In addition, the continuous tunnel trim with its comfortable armrest emphasises the spacious dimensions of the interior.

Materials: only the very finest

It is immediately obvious to anybody sitting in one of the integral seats that the new CL-Class fits like a tailor-made suit. Everything is perfectly coordinated: forms, colours and materials. There is a choice of five tasteful colour combinations: black/black, basalt grey/dark basalt grey, cognac brown/black, savanna beige/cashmere beige and sahara beige/black.

Mercedes customers are also able to satisfy their individual wishes with a choice of fine wood trim for the centre console, doors and rear side panels: even the burr walnut coming from California is available in two variations – with a dark gloss or matt silk finish. Black ash wood is another option, and hand-selected poplar wood is specially reserved for the CL 600. In the top-of-the-line V12 model it is also used for the wood/leather steering wheel and for the handrest of the COMAND controller.

The seat upholstery is also to the highest standards. Three different grades of leather are available, all with a low level of pre-tensioning for a ruffled effect and a soft, comfortable appearance even at first glance. This appealing visual impression is enhanced even further by the feel of the particularly soft PASSION leather upholstery. If PASSION leather upholstery is ordered as an optional extra (standard in the CL 600), the dashboard, centre console and interior door panels are also lined in this fine nappa leather. Choosing this top-of-the-line interior means that the roof lining and the A and C-pillar linings are also enhanced with high-quality Alcantara -- haute couture on wheels.

At a glance: design and equipment features of the CL models*

CL 500	CL 600
Wood trim in black ash wood, alternatively dark or silk matt burr walnut	Poplar wood trim with wood/leather steering wheel
Leather upholstery	PASSION leather interior with Alcantara roof liner
Door sill panels in high-gloss aluminium	Chromed stainless steel door sill panels and chromed boot sill
17-inch seven-spoke light-alloy wheels	18-inch light-alloy wheels in a special V12 design
	designo seats
	Brake callipers with Mercedes-Benz lettering
	Chrome inserts on lower air intake and chrome fog lamp surrounds
	V12 emblem on both front wings

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Control system: intuitive interface

"User interface design" is a new term in the world of automotive development. It refers to the clear layout and design of the dashboard displays, switches and controls, so that the driver intuitively understands their functions while they blend attractively into the overall design concept. The new CL-Class also sets standards in this field.

The newly developed control system (see page 52) combines high-quality materials and elegant surroundings with an appealing clarity and exemplary practicality. The engineers and designers have worked together closely to ensure that the visual appearance and technology are in harmony.

Immediately obvious features include the luxurious switches and controls, which are all designed to a uniform style: all the switches, buttons and rotary controls are of aluminium, or have a finely structured metallic surface, which lends them an appearance of being cast in the same mould. The highly polished black display surfaces form a pleasant contrast to the metallic, silver-coloured switches. They are internally illuminated and carry symbols to denote their function.

The designers and engineers had the shared aim of reducing the number of switches and controls. Important functions still remain directly accessible to the driver, while less frequently used systems can be conveniently controlled using COMAND. Controls with similar functions have been grouped into arrays, for example the seat adjustment controls, the switches for the power windows or the air conditioning/ventilation controls. Many of these function groups feature fine chrome surrounds which further underline the very high quality of this top-class Mercedes Coupé. The effect is also enhanced by the COMAND controller and the handrest with its fine leather or fine wood trim. Beneath its lid – as if nestling in a jewel case – lies the telephone handset.

The designers were also responsible for the appearance of the displays and controls, therefore the lettering, graphics and layout bear a uniform signature. To create a user-friendly display interface the specialists developed photo-realistic illustrations which clearly and logically support the relevant control process. For the COMAND display they developed an intuitive and easily operated menu system, placing great emphasis on large, easily legible lettering and a clear structure to ensure that operation is as simple and precise as possible.

5: Safety (I)

Safety (I)

PRE-SAFE®: automatic partial braking before an impending rear-end collision

Night view assist: infra-red light for better visibility

Intelligent Light System: adaptive headlamps as standard

Body structure: effective all-round occupant safety

Restraint systems: crash sensors for situation-related protection

For Mercedes-Benz, automotive safety is not merely a matter of crash tests during which specific types of impact are simulated under laboratory conditions. The specialists in Sindelfingen are primarily interested in reality: in what actually happens in traffic situations and accidents, and in the many critical situations where cars must prove their capabilities. The comprehensive Mercedes-Benz concept takes all the aspects of safe driving into account – from accident prevention to occupant protection and the quickest possible recovery of accident victims.

One of the mainstays of this philosophy is the anticipatory occupant protection system PRE-SAFE®, which is standard equipment in the new CL-Class. Accordingly the Mercedes Coupé features a safety technology which no other car in this class offers, worldwide. For the first time this system is able to create a synergy between active and passive safety: on the basis of sensor information from active handling safety systems, which register the danger of a skid or very heavy braking within milliseconds, PRE-SAFE® uses the time between detection of a potential accident and activation of the protective systems in the vehicle interior. During this interval PRE-SAFE® prepares the occupants for the impending collision as a precaution.

In other words, PRE-SAFE® gives the car reflexes. When danger is detected, the new CL-Class responds as reflexively as a living being and activates the appropriate protective measures to avoid the risk of injuries or reduce their severity. This Mercedes invention is in line with the findings of accident researchers, which show that more than two thirds of all serious accidents are preceded by critical driving manoeuvres that allow an impending collision to be predicted in advance. In the new CL-Class, PRE-SAFE® uses this advance accident detection phase, which can have a duration of several seconds in some cases, to ...

move the front passenger seat to a more favourable position with respect to height and fore-and-aft adjustment, as well as cushion and backrest angle, during emergency braking, so that the seat belt and airbag are able to work most effectively during an impact, and to inflate the air chambers in the dynamic multicontour seats (optional) to support the driver and front passenger and press them more firmly into their seats.
additionally close the front side windows and sliding sunroof if the car starts to skid, so that the occupants are not thrown out and the windowbags have better support during a side impact or rollover.

Automatic partial braking when a collision is imminent

The newly developed PRE-SAFE® Brake system improves this preventive occupant protection even further. This system, which is absolutely unique worldwide in the extent of its functions, automatically brakes the CL-Class before an impending accident and operates in tandem with the Brake Assist PLUS (BAS PLUS) system introduced last year, which warns the driver of an imminent rear-end collision with visual and audible signals and automatically calculates the required braking pressure to prevent an accident. This braking-power support is available as soon as the brake pedal is operated.

The PRE-SAFE® Brake system goes one step further: if the driver does not react to the BAS PLUS warnings, the PRE-SAFE® Brake system triggers automatic partial braking where an accident is imminent and slow the CL Class down at a rate of up to 0.4 g (around 4 m/s²), corresponding to around 40 percent of the total braking power. The automatic partial braking provides the driver with another clear warning to act. If the driver then immediately applies the brakes, the maximum braking force is available and the accident can - depending on the situation - be averted at the last moment. If an accident is unavoidable, the PRE-SAFE® Brake system reduces the impact severity and, in turn, the risk of injury to the vehicle occupants.

The anticipatory PRE-SAFE® measures on board the new Mercedes Coupé are also activated automatically when the PRE-SAFE® Brake system goes into action: as soon as the system commences automatic partial braking, the supporting bolsters in the dynamic multicontour seats are inflated, the seat cushion and backrest angles are adapted and the front passenger seat is moved to the most favourable position.

Radar sensors in the bumper and behind the radiator grille

The anticipatory Brake Assist PLUS and the new PRE-SAFE® Brake system are part of the DISTRONIC PLUS equipment package. In addition to the 77 Gigahertz long-range radar of the proximity control system, these systems use newly developed short-range radar based on 24 Gigahertz technology. While the DISTRONIC radar is configured to monitor three lanes of a motorway up to a range of 150 metres with a scanning angle of nine degrees, the new 24 Gigahertz radar monitors the area immediately in front of the vehicle to a range of 30 metres and with a scanning angle of 80 degrees.

Accident severity reduced by 40 percent

Mercedes-Benz has intensively tested the effectiveness of the new PRE-SAFE® Brake system. In the DaimlerChrysler Research driving simulator in Berlin, Mercedes engineers conducted a series of tests with 70 drivers who were deliberately distracted by an accident on the opposite carriageway during their journey, while the traffic ahead of them suddenly braked at the same time.

The results of these tests demonstrate the increased safety made possible by the state-of-the-art support systems in the CL-Class: thanks to the rapid reaction of the drivers and the help of BAS PLUS with the PRE-SAFE® brakes, an accident was avoided during 70 percent of these journeys. In one third of these simulator tests the participants were unable to prevent an accident. In these cases the automatic partial braking function ensured a reduction of around 40 percent in impact severity.

Flashing brake lights: effective warning when danger threatens

Mercedes-Benz has developed flashing brake lights as a further contribution to the prevention of rear-end collisions. These are standard equipment in the new CL-Class. If the driver is obliged to brake hard from a speed of more than 50 km/h, or if Brake Assist is activated to support the driver in an emergency, the brake lights flash to warn traffic following behind. If the CL-Class is brought to a standstill after such an emergency braking manoeuvre, the brake lights revert to continuous operation and the hazard warning flashers are switched on at the same time.

Studies carried out by Mercedes engineers show that drivers’ braking reaction time can be shortened by up to 0.2 seconds on average if a flashing red warning light is substituted for a conventional brake light in emergency braking situations. As a result, the braking distance can be reduced by around 4.4 metres at a speed of 80 km/h, and by as much as 5.5 metres at 100 km/h.

ABS, ASR, ESP®, Brake Assist – all these are further driving safety systems on board the new CL-Class which can effectively contribute to accident prevention.

Night view assist: even better visibility at night

Mercedes-Benz has developed the night view assist system to improve driving safety even further, especially during the hours of darkness. This increases the driver’s range of visibility to up to 200 metres to reduce his workload when driving at night. This means that the system provides roughly the same range of visibility as high beam headlamps – but without dazzling oncoming traffic.

Night view assist, which celebrated its debut in the S-Class in autumn 2005 and is also available for the CL Coupé, features two additional, infrared headlamps. Their light is invisible to the human eye, and therefore does not dazzle oncoming drivers. An infrared-sensitive camera on the inside of the windscreen shows the scene ahead of the vehicle on a display in the instrument cluster of the luxury Coupé, enabling road signs, pedestrians, cyclists, debris or other obstacles in the road to be identified much sooner.

When night view assist is active, the infrared headlamps are automatically switched on when a speed of 15 km/h is reached and remain on when braking down to about 10 km/h.

As soon as night view assist is activated, the display in the centre of the instrument cluster switches over to show the camera image. The large eight-inch display is directly in the driver’s field of vision, and provides a clear greyscale image of the road ahead. The driver is able to glance down at the infrared image regularly, monitor the situation ahead of the vehicle and adapt his style of driving accordingly.

Up to 125 percent increase in safety

Mercedes engineers have examined the capabilities of this technology in a series of practical trials. During comparative test drives with low-beam bi-xenon headlamps and the new night view assist system, male and female test drivers recognised obstacles in the road much sooner when assisted by the infrared light system. During tests, drivers were already able to discern test dummies at the roadside dressed in light-coloured clothing at a range of around 210 metres, which is about 41 metres sooner than with low-beam bi-xenon headlamps.

The system proves even more effective in the case of pedestrians in dark clothing. In these situations the night view assist system already enabled the drivers to identify the test dummies at a range of around 164 metres, compared with only at about 72 metres when driving with low-beam bi-xenon headlamps alone. This represents a safety improvement of no less than 125 percent.

Even when the headlamps of oncoming vehicles dazzle the driver and severely obscure the view, visibility is much better with this assistance system: a test dummy in light-coloured clothing standing at the road edge 50 metres behind an oncoming vehicle was detected from an average distance of 140 metres with the help of night view assist – around 53 metres sooner than with low-beam bi-xenon headlamps.

The state-of-the-art CMOS sensor (Complementary Metal Oxide Semiconductor) and the infrared camera specially developed for Mercedes-Benz are able to reduce dazzle by electronic means, while enhancing the rest of the image to ensure that even smaller details are easily recognised.

Important contribution to safer driving in the dark

Night view assist is able to contribute greatly to improved road safety, as accident analyses carried out by Mercedes-Benz have confirmed: on the basis of data obtained from a joint accident research project conducted by German vehicle manufacturers and the federal office for roads and traffic, specialists at Mercedes-Benz analysed accidents occurring during the hours of darkness and found that the night view assist system has a very high safety potential.

The risk of serious injury in road traffic is much greater in twilight and in the dark than during daylight hours. Collisions at night are predominantly driver-induced accidents during which drivers lose control of their vehicles – often because they have not recognised the course of the road soon enough in the dark, and failed to adjust their speed. As a result around half of the vehicles in question leave the road, while more than one quarter collide with oncoming traffic. Night view assist can also help to improve the safety of pedestrians. According to German accident statistics, more than 55 percent of fatal accidents involving pedestrians occur in twilight or at night.

Intelligent Light System: latest lighting technology as standard

The Intelligent Light System developed by Mercedes-Benz also contributes to driving safety at night. This represents the most advanced headlamp technology currently available, and is standard equipment in the new CL-Class. This intelligent lighting system is based on powerful bi-xenon headlamps. These are variably controllable, and are networked with other electronic control units on board the new luxury Coupé, from which the headlamps obtain information about the current driving situation and distribute their beam patterns accordingly.

The familiar low-beam headlamps with their well-proven, asymmetrical light distribution are replaced by the new country road mode, which illuminates the driver’s-side edge of the road more widely and brightly than before. In the dark, this enables the driver to appraise the situation and respond more rapidly when other road users cross his path.

Motorway mode, which comes on automatically when driving above 90 km/h, increases the driver’s range of vision by up to 60 percent. This lighting function is activated in two stages: the Intelligent Light System first increases the output of the bi-xenon lamps from 35 to 38 watts, thereby increasing the light intensity and providing noticeably better illumination of the road ahead and the side verges. The second stage of motorway mode becomes available at 110 km/h and above. The beam of the bi-xenon module on the driver’s side is elevated slightly, while the high-beam spotlights of the CL-Class are switched on as well. A baffle in front of these spotlamps projects a light/dark cutoff onto the road to prevent oncoming drivers from being dazzled.

The new motorway mode has a range of around 120 metres, and the driver is able to see about 50 metres further at the centre of this cone of light than with conventional low-beam headlamps.

Headlamp automatically pivots outwards

With the enhanced fog lamps, Mercedes-Benz also provides drivers with better orientation in adverse weather conditions. This new lighting function is activated at speeds below 70 km/h, as soon as the rear fog light is switched on. The variable headlamp technology of the Intelligent Light System makes it possible to pivot the bi-xenon headlamp on the driver’s side outwards by eight degrees, while lowering its beam. This illuminates that side of the road more brightly and reduces the glare from reflected light in foggy conditions. The enhanced fog lamp function remains active up to a speed of 100 km/h.

The Intelligent Light System also includes the active headlamp and cornering light functions. These are switched on automatically: depending on the steering angle, yaw rate and vehicle speed, with the active headlamp function the headlamps pivot sideways by up to 15 degrees in fractions of a second, thereby greatly improving road illumination. On a gradual bend with a radius of 190 metres, the driver is able to see 25 metres further than with conventional low-beam headlamps thanks to this system. This function operates with both low and main-beam headlamps.

The cornering light function integrated into the main headlamps improves safety when entering junctions, openings and tight bends. It is automatically activated if the driver operates the indicators at a speed below 40 km/h or turns the steering wheel at a speed below 70 km/h. The headlamps 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 new, adaptive headlamp technology has been made possible by a ruling by the UN Economic Commission for Europe (ECE), which also applies within the European Union. Mercedes-Benz is the world’s first automotive brand to offer intelligent car headlamps.

6: Safety (II)

Safety (II)

Passive safety: to the highest Mercedes standards

The new CL-Class has an equally pioneering role in the field of passive safety. This is mainly due to the sophisticated bodyshell structure and highly effective restraint systems.

The forces generated during a frontal impact are dissipated at several levels to ensure that the passenger cell remains substantially undamaged. The front-end module and the so-called integral member, on which the engine, steering and front axle are mounted, join the front side members and the second level of side members together. During a frontal crash this creates two important energy dissipation channels which substantially contribute to occupant protection in the CL-Class. At the same time the robust, multi-skinned side members are able to absorb large forces and direct impact energy past the passenger cell. During severe offset collisions, the front wheel affected is braced by a specially designed energy-absorbing element acting as a forward extension of the side member.

The concept of the continuous firewall cross-member is also new in the CL-Class. During an offset frontal crash, this widely distributes the impact forces into the transmission tunnel and the side members. An additional, upper member increases the rigidity of the firewall and reduces pedal intrusion into the interior in the event of a frontal impact.

The V-engines of the CL-Class make a further, important contribution to occupant protection. Thanks to their compact construction, they allow a higher deformation of the front-end structure during a frontal impact, reducing the loads acting on the passengers. The propshaft is also equipped with special deformation elements.

Distributing impact forces over several vertical and horizontal structures with specifically defined energy levels not only benefits occupant protection, but also serves the interests of compatibility during collisions with smaller vehicles. The front-end structure of the new CL-Class is designed to ensure that crash energy is also dissipated for the other vehicle.

Robust floor structure with eight longitudinal members

Whether during a frontal or rear-end crash, lateral impact or rollover, the passenger cell is an extremely robust structure which is able to offer the occupants an intact survival space even at high impact speeds. High-strength steels and thicker steel panels play an important part in this, as does the installation of additional structural members.

An intelligently designed floor structure forms the robust basis for effective occupant protection: eight longitudinal members, four cross-members and triple tunnel reinforcement stabilise the passenger cell during a crash, and ensure that the impact forces are distributed over a wide area.

Side structure of higher-strength steel

During a side impact, the robust side members, the B-pillars, the four cross-members at floor level and a solid steel section below the dashboard are responsible for the stability of the passenger cell. For the first time Mercedes-Benz has used higher-strength steel alloys for the side members and B-pillars. In terms of tensile strength these are far superior to any other material. Side impact protection is also the purpose of the high-tensile reinforcing sections of aluminium integrated into the doors. Mercedes engineers also devoted particular attention to the door hinges, for which they developed special, high-strength mounting plates. This creates a robust, integrated structure which is able to provide effective protection to the occupants in the event of a lateral collision.

Rear-end structure designed to withstand extreme impact loads

As for frontal and side impacts, the new CL-Class meets the most stringent safety standards where a rear-end impact is concerned, for example the new US legislation which prescribes an offset crash (70 percent overlap) with an impact speed of 80 km/h.

The fact that the passenger cell remains substantially undamaged despite this extremely high load is due to the sophisticated deformation zone at the rear. In addition to an aluminium cross-member and the steel crash boxes of the bolt-on rear-end module, this consists of two robust side members and a cross-member in the area of the boot floor. The rear axle subframe also forms an energy-absorbing level during an impact. The fuel tank is located in a protected area in front of the rear axle.

Restraint systems: activation according to accident severity

During a crash, an effective restraint system goes into action to protect the vehicle occupants as the situation requires. To this end a computer not only uses various sensors to evaluate the severity of an impact, but also the personal data of the front passenger. If the sensors in the seat cushion identify the front passenger as small, then depending on the type of accident, they initially only activate the first airbag stage for less than maximum inflation. If a larger front passenger is detected, both airbag stages are activated. The well-proven automatic child seat recognition system is also on board. This deactivates the front passenger airbag as soon as a rear-facing child seat with a transponder is detected. The airbag, sidebag and belt tensioner are deactivated when the front passenger seat is unoccupied.

The engineers in Sindelfingen have also made further improvements to the sensor systems. The new CL-Class has a total of eleven sensors which supply information about the type and severity of an impact at an early stage:

Frontal impact: In addition to the central sensor in the airbag control unit, the CL-Class is equipped with so-called up-front sensors. By virtue of their exposed position on the front-end module, these are able to detect the severity of a collision even earlier and with greater accuracy, which enables the time between the crash and activation of the airbags and belt tensioners to be reduced even further. The belts can therefore be tensioned at a very early stage, so that the occupants are connected to the passenger cell during an impact and benefit from the deceleration of the body structure.
Side impact: New pressure sensors rapidly and reliably inform the control unit when a lateral impact occurs in the door area. These sensors respond when the air between the outer skin and the interior panel of the door is compressed by an impact. Additional side sensors are installed in the B-pillars of the new CL-Class.
Rear-end collision: The central crash sensor in the interior of the new CL-Class recognises a rear-end collision. If the impact is severe, the belt buckle tensioners in the front and rear are activated to hold the occupants more firmly in their seats.
Rollover: In the event of a rollover, a rollover sensor integrated into the airbag control unit is able to activate the belt tensioners, and if necessary the windowbags.

Belt tensioner and belt force limiter for every seat

In addition to the two-stage front airbags for the driver and front passenger, the standard occupant protection system in the new CL-Class includes a total of six side protection airbags: two sidebags in the front seat backrests, two sidebags in the rear side panels and two large windowbags.

All the occupants have the benefit of three-point inertia-reel seat belts with belt tensioners and belt force limiters. The loads acting on the occupants are also reduced by the newly developed steering column, which collapses telescopically by up to 80 millimetres during a frontal collision.

Mercedes safety even after an accident

The comprehensive Mercedes safety concept PRO-SAFE also takes the post-accident phase into consideration. In order to prevent consequential damage, the fuel supply to the engine is automatically interrupted if the new CL-Class is involved in an accident of sufficient severity. The hazard warning system is also switched on to warn following traffic and prevent further accidents.

After an accident with airbag activation, all the side windows are opened very slightly to ventilate the interior. The door locks are also automatically unlocked so that helpers are able to recover injured passengers more rapidly. Specially designed crash joins prevent the doors from being jammed shut by the wings. The occupants are also able to open the doors after an accident, as Mercedes-Benz uses Bowden cables, which remain intact after deformation, to operate the door catches from the inside. Like the S-Class, the new CL-Class has markings on the rear windscreen which indicate the points where the emergency services should cut through the C-pillars after a serious accident, in order to reach the occupants rapidly for medical treatment.

7: Body

Body

Materials: combination of high-tech steel and aluminium

Processes: high-strength bonding for outstanding load-resistance

Aero-acoustics: quietest car in its class

The bodyshell of the new CL-Class is another excellent example of how very different aspects can be successfully integrated. As a robust backbone it stabilises the running gear, ensures precise handling and prevents uncomfortable vibrations. It also meets the most stringent Mercedes safety standards with its intelligent lightweight construction, has exemplary aerodynamic properties and has made audible progress in the field of vehicle acoustics.

These results are based on the careful selection of materials on the well-tried Mercedes principle of "the right material in the right place". The material mix consists of steel, aluminium and plastics, with steel continuing to play the major role. Here too, a technological change is taking place: conventional deep-drawn steels are becoming less important, and only account for around 26 percent in the new Mercedes-Benz CL-Class. Instead the specialists in Sindelfingen have opted for high or higher-strength steel alloys, which achieve maximum strength with minimum weight. Accordingly the proportion of these steel types has increased from eleven to around 44 percent compared to the preceding model.

In addition, ultra high-strength, high-tech steel alloys are used in body areas which are important for occupant protection. These are already formed in a warm state, thereby achieving an extremely high tensile strength which exceeds that of conventional steels by a factor of three. This means that half the bodyshell of the new CL-Class consists of high-tech steel alloys.

Mercedes-Benz uses the lightweight material aluminium where it has most advantages compared to steel. In the new CL-Class these areas are:

Bonnet
Front wings
Exterior door panels
Front-end module member
Rear-end module member
Bulkhead behind the rear seat backrest
Rear end centre assembly

The boot lid and spare wheel recess are likewise of lightweight material, namely plastic.

High-tech adhesive in addition to welded connections

In addition to these high-tech materials, a combination of modern joining techniques contributes to the exemplary torsional and flexural rigidity of the bodyshell. A new, high-strength structural adhesive supplements conventional processes such as spot/laser welding and low-stress clinching. The adhesive creates a firm bond between the steel flanges, significantly increasing the load resistance and transfer of forces in safety-related areas. The total length of high-strength bonded seams in the new CL-Class has more than doubled versus the preceding series.

The precise dimensions of the body components, low-stress joining techniques and the latest spot or laser welding processes make additional brazed connections and MAG welding seams between the steel panels almost completely unnecessary – a major contribution to the durability of the bodyshell.

Easily repaired modules at the front and rear ends

The engineers in Sindelfingen adopted the well-proven modular concept for the front and rear ends of the new CL-Class, though with certain detailed design improvements. The flexible cross-members of these modules are now of high-strength extruded aluminium sections. These are connected to the longitudinal members via steel crash boxes, and designed so that the impact energy of a low-speed collision is first absorbed by the aluminium sections and crash boxes. This means that the downstream body structure remains undamaged. During an offset frontal collision, the robust cross-members also have the task of transferring impact energy to the unaffected side of the body structure.

The front and rear-end modules are bolted to the bodyshell, and can be replaced without troublesome welding work if repairs are required. The individual components within the modules are also connected with bolts.

Hybrid construction of two lightweight materials for the doors

The doors are of frameless, lightweight aluminium/magnesium construction: the interior parts are of magnesium, while the outer skin is of aluminium alloy. Side impact protection is provided by internal reinforcing sections of high-tensile aluminium. Mercedes engineers also devoted particular attention to the door hinges, for which they developed special, high-strength mounting plates. This creates a robust, integrated structure which provides effective protection to the occupants in the event of a lateral collision.

In addition to a high level of safety, the doors of the new CL-Class also have functions which make access and egress easier. A newly developed hydraulic system ensures that the open doors remain in position above an opening angle of 15 degrees – even on gradients or in strong wind. An electric servo mechanism pulls both doors (and the boot lid) closed.

Long-term protection: fully galvanised bodyshell and paint with nano-particles

Mercedes-Benz has developed an effective package of measures for long-term anti-corrosion protection. This is based on fully galvanised body panels, some of which have an additional organic coating on both sides depending on their location, e.g. on the doors or on the front, side and rear longitudinal members. This coating also contains rust-inhibiting zinc pigments. Mercedes-Benz also protects the most vulnerable structural areas of the bodywork with a cavity-fill preserving agent, for example on the front side members, the upper side member plane, the side members and the rear wheel arches.

The Mercedes-Benz experts also weather-seal the welding seams in order to prevent the onset of corrosion. This seam sealing benefits not only the bonnet, doors, tailgate, rear wheel arches and fuel filler flap, but also a large proportion of the welded joins in the floor structure of the new CL-Class. Using plastic for a large area of the underbody panelling has allowed Mercedes engineers to dispense with conventional PVC underseal. This underbody panelling protects the body from stone chippings, water and soiling.

In keeping with all Mercedes passenger cars, the new CL-Class is also protected by the 30-year MobiloLife warranty.

Mercedes-Benz also makes a major contribution to exemplary long-term quality and value retention with a scratch-resistant clearcoat based on nano-technology. This innovative paint system, which celebrated its world debut at Mercedes-Benz, is a standard feature of the new CL-Class and is used for both metallic and non-metallic finishes.

Thanks to advances in the field of nano-technology, it was possible to integrate the tiny ceramic particles measuring less than one millionth of a millimetre into the molecular structure of the paint binder. These particles effect a three-fold improvement in the scratch-resistance of the paint finish and ensure a visibly brighter, long-lasting sheen.

Aerodynamics: exemplary wind resistance and wind noise

The aerodynamics engineers at Mercedes-Benz have achieved another triumph where the new CL-Class is concerned. Despite larger wheel arches and greater demands in terms of engine cooling and interior climate control, the luxury Coupé has an even better coefficient of drag than its predecessor, with a Cd value of 0.27. This means that the new Mercedes Coupé also sets the standard for its class where aerodynamic efficiency is concerned.

The key aerodynamic figures for the new CL-Class at a glance:

Coefficient of drag (Cd value)	0.27-0.28
Frontal area (A)	2.28-2.30
Wind drag area (Cd x A)	0.62-0.64
Front axle lift (c_FL)	0.08-0.09
Rear axle lift (c_RL)	0.04-0.05

The fact that the good aerodynamics of the CL-Class not only produce an exemplary Cd value, but also have a positive effect on handling safety, is demonstrated by the favourable values for front and rear axle lift. These are up to eleven percent lower than those of the preceding model, and are reliable indicators of high braking stability, good roadholding and a low susceptibility to side winds.

Comfort as an audible experience

The good aerodynamics of the CL-Class are also noticeable in acoustic terms, for if the airstream passes across the outer skin with minimal turbulence in the interests of low drag, this also leads to less noise. As early as the conceptual phase, Mercedes engineers took pains to ensure that the bodyshell was optimally streamlined so that wind noise was reduced.

It was with this in mind that they designed the airflow-efficient A-pillars, developed a more rigid bodyshell with reinforced outer surfaces and achieved a new sealing concept for the doors, which is acoustically even more efficient than in the preceding model. This exemplary noise insulation is also helped by the side windows, which have a thickness of six millimetres in the new CL-Class.

Many other components were also developed with a view to aero-acoustic efficiency: for example the windscreen wipers, which are positioned very low down, out of the airstream, when parked. A narrow stem between the exterior mirror housings and the doors also prevents wind noise, and a specially designed rubber seal between the rear window and the boot lid also makes for aero-acoustic efficiency. The tilting/sliding sunroof features serrated wind deflectors whose ridges create designed-in longitudinal air turbulence, thereby reducing thrumming noises when the roof is open.

Noise analyses with a three-metre parabolic mirror

To carry out their aero-acoustic measurements, Mercedes engineers developed a new procedure involving a three-metre parabolic mirror fitted with numerous microphones, which acts as a sound reflector. From a distance of five metres, the microphones at the focal point of the mirror record the noises caused by the airstream as it passes around the vehicle body.

While numerous individual measurements were formerly necessary for such analytical procedures, the new parabolic mirror process requires only a single measurement to examine complete areas of the vehicle body, e.g. the A-pillar, exterior mirror, side window and roof.

A video camera makes the area under examination visible on the computer screen. At the same time the system superimposes the wind noises onto the video image as different-coloured areas, depending on the sound volume and frequency. This enables sources of irritating noise and its distribution to be identified and examined.

During the development of the new CL-Class this innovative aero-acoustic measuring procedure was supplemented with well-proven artificial head technology: a dummy with an artificial head, whose anatomically accurate auditory passages were equipped with capacitor microphones, was seated behind the steering wheel. These made both spatial sound recordings and precise measurements of sound pressure and frequency possible.

Subsequent evaluation of the test results showed how effective the noise reduction methods were. The acoustically sensitive area at the driver’s head level appears as a blue, particularly quiet zone on the computer screen of the parabolic mirror microphone system. At a wind speed of 140 km/h, the interior noise level in this area is below 66 decibels.

Background noise subjectively perceived as pleasant

In addition to taking measurements, Mercedes engineers also consider it important to establish how male and female drivers perceive the level of acoustic comfort. This is because some noises which the equipment registers as quiet can in fact be irritating, and compromise comfort on long journeys. They therefore use analytical methods which better reflect human audio-perception and provide key psycho-acoustic information about subjective perception of background noise.

One of these parameters is loudness, for example. This is calculated on the basis of different frequency groups, and is better able to describe how humans perceive loudness than the noise level in decibels. At a wind speed of 140 km/h, an outstanding result of just 19 sone was measured in the new CL-Class. Other criteria for noise comfort include harshness, which predominantly evaluates high frequency noises such as hissing or whistling, and the articulation index. This indicates how easily the car occupants are able to converse during a journey. For example, it is irritating if the airstream creates a continuous, high-frequency rushing sound which makes conversation more difficult.

Mercedes engineers arrived at an articulation index of 78 percent for the new CL-Class. This is more than ten percentage points above that of the preceding model, and significantly exceeds the value for other cars in the luxury class. The ideal conditions are therefore in place for easy communication between the driver, front passenger and rear seat occupants.

Hearing tests with 60 male and female drivers confirmed the effectiveness of these aero-acoustic developments in the new Mercedes Coupé. They were asked to evaluate certain noises, and thereby helped the engineers to achieve favourable aero-acoustic values.

Windscreen wipers: aero-technology with two motors

The windscreen wipers of the new CL-Class were also developed in the wind tunnel: they are known as aero-wipers. Instead of the articulated retention system used for conventional wiper blades, in which the rubber blades are claw-mounted, the aero wiper consists of a one-piece rubber section with an integral spoiler and externally mounted spring rails; these precisely follow the curve of the windscreen. The spring rails ensure an even distribution of wiper pressure along the entire length of the wiper blade, so that it always operates with the greatest possible contact pressure. The result is significantly better wiping quality, while wiper noise is considerably reduced.

The wipers on the driver and front passenger sides are powered by two motors, and have different kinematics: while the driver's-side wiper arm moves around a fixed axis, its counterpart on the passenger side executes an additional lifting movement to wipe an even larger area of the windscreen. The rain sensor which controls the windscreen wipers according to rain intensity is standard equipment, and can be adjusted in two sensitivity stages using the multifunction stalk on the steering column.

Windows: silver foil as an infrared reflector

The new CL-Class leaves the production line with infrared-reflecting, laminated glass which also has an invisible coating of pure silver. This not only filters out UV radiation, but also light in the infra-red spectrum which is mainly responsible for heating up the interior. Compared to green-tinted glass, this reduces the energy radiation into the interior from 60 to around 47 percent at the windscreen.

8: Support Systems

Support Systems

DISTRONIC PLUS: proximity control from zero to 200 km/h

Parking guidance system: convenient parking with radar

In 1998 a long-held dream for many drivers was fulfilled with the Mercedes-developed DISTRONIC proximity control system: an electronic co-pilot which keeps the car at a set speed and at a set distance from the vehicle ahead – for more convenience and less stress. Mercedes-Benz has now developed this highly efficient support system even further, hence the name DISTRONIC PLUS.

By combining the previous DISTRONIC radar (77 GHz) with a newly developed close-range radar (24 GHz), which is also used for Brake Assist PLUS, Mercedes engineers have been able to extend the working range of the proximity control system even further, so that it can now scan a distance of anything from 0.2 to 150 metres. While the 77-Gigahertz radar monitors the road ahead over a long distance, the signals from the 24-Gigahertz sensors have a range of around 30 metres and monitor the immediate vicinity of the vehicle. The electronic control unit analyses the information received from both radar systems and calculates the engine, automatic transmission and braking parameters required for proximity control.

In addition, the speed range for this control function has been increased from the previous 30 - 180 km/h to zero - 200 km/h. This means that when the traffic tails back, DISTRONIC PLUS automatically brakes the CL-Class to a standstill and accelerates back to the set speed as soon as the traffic situation allows. To move off automatically, the driver only needs to operate the DISTRONIC stalk on the steering column or briefly depress the accelerator.

As before, the required interval can be set according to the traffic flow and density: using a control function on the DISTRONIC stalk, the driver is able to variably adjust the time lapse between one and two seconds if required by the traffic situation. The medium setting corresponds to a time lapse of 1.5 seconds, representing a gap of around 42 metres at a speed of 100 km/h. The target and actual distances between the CL-Class and the vehicle ahead are shown in the central display of the instrument cluster.

Automatic braking to a standstill

As more dynamic proximity control intervention is often required at lower speeds, i.e. in stop-and-go traffic with frequent starting and braking, the acceleration and deceleration values of the system have been reconfigured. Depending on the speed, automatic deceleration of up to four m/s² (previously two m/s²) is now possible. If DISTRONIC PLUS detects that heavier braking is required, a warning light appears in the instrument cluster. This is accompanied by an intermittent, audible warning which tells the driver to watch the traffic situation and apply the brakes himself if necessary.

The electronic proximity control system can be activated independently of DISTRONIC PLUS. In this case too, the system continuously monitors the distance from the vehicles ahead and gives the driver an audible warning if he is approaching another vehicle too rapidly at a speed of more than 30 km/h, and lights up a warning lamp if the gap is too small.

Parking guidance system: radar technology shows the way into a parking space

A newly developed parking guidance system is celebrating its series production debut in the CL-Class. This uses radar technology to help the driver find a suitable parking space and park the vehicle. When driving past at a speed of up to around 40 km/h, side-mounted radar sensors in the front and rear bumpers of the new luxury Coupé measure whether the parking spaces on the driver and front passenger sides are sufficiently large for the vehicle. Once the system has found a suitable parking space on the front passenger side, a blue "P" symbol appears in the instrument cluster if the vehicle speed is below 16 km/h. Parking spaces on the driver’s side are shown if the indicator on that side is operated.

Once the driver has stopped the Coupé in the position shown on the display and engaged reverse gear, the display shows a symbolic, bird’s-eye-view representation of the parking situation. Coloured guide lines show the driver how best to park: a red line indicates the current steering angle, while a blue line shows the steering angle required for parking. The driver now turns the steering wheel until the two lines coincide, and can then begin to reverse slowly.

As soon as the ideal and actual steering angles coincide, the guide lines on the display change to green. When reversing, an acoustic signal informs the driver when it is time to countersteer.

During the parking manoeuvre, the guidance system continuously monitors the steering angle and vehicle position. If the driver stops before reaching the recommended position, for example, the system automatically recalculates the ideal steering angle for smooth parking.

The new, radar-based parking guidance system, which will be optionally available for the new CL-Class from the end of 2006, works in tandem with the Parking Assist feature familiar from the S-Class. This system uses radar to measure the distance to obstacles in front of and behind the car, informing the driver by means of the display and an intermittent acoustic warning.

The system uses the four close-range sensors at the front and two radar sensors in the rear bumper to assist the driver when parking or warn him of obstacles when reversing. The newly developed system operates with a much greater range and coverage than PARKTRONIC, which is based on ultrasound technology. The radar sensors of Parking Assist operate up to a distance of eleven metres and have a scanning angle of 40 degrees, which means that the driver is warned of an impending collision much sooner. This is an advantage which becomes particularly obvious when reversing over a longer distance. In this case the system is active from a speed of seven km/h, and warns the driver with an audible signal if a collision threatens. This allows enough time to prevent the collision with firm operation of the brake pedal.

When parking the vehicle, the system assists the driver within a speed range from zero to 16 km/h. When moving forward, the colour display in the instrument cluster shows two segments which indicate the distance from an obstacle within the range of the radar sensors on the left and right sides. When the first red segment lights up an intermittent warning is also sounded. A constant warning note is sounded when the second red segment is reached, informing the driver that the minimum distance has been reached. When reversing, a display in the rear roof liner is switched on and indicates the distance from any obstacles – once again for each side of the vehicle and with an acoustic warning over the last few centimetres.

Reversing camera: electronic eye in the boot lid

The new CL-Class can also be supplied with the proven PARKTRONIC ultrasound-based parking system, which assists the driver when parking. A special reversing camera provides further assistance. The reversing camera, mounted in the boot lid above the licence plate, is activated automatically when the driver engages selector position "R". It projects an image of the area behind the vehicle onto the COMAND display. Based on the vehicle dimensions, speed and steering angle, a control unit calculates the optimal path the vehicle should take into the parking slot. Coloured lines are superimposed on the camera image to guide the driver.

LINGUATRONIC: voice control for radio, audio, telephone and navigation

For a number of years now, this Mercedes-Benz-developed voice control system has been establishing itself as an important support system which enhances both safety and convenience. In the new CL-Class, the driver can use LINGUATRONIC (optional) to control the telephone, audio system and navigation system. After activating LINGUATRONIC using a button on the steering wheel, all the driver has to do is say the word - or words - and the radio will search for or store another station, switch to the next track on a CD or enter the desired destination in the navigation system. In this way LINGUATRONIC reduces driver stress, allowing him to devote more attention to the road and traffic conditions.

9: Interior (I)

Interior (I)

Control system: clear and intuitive with the

COMAND controller

COMAND: even more efficient with navigation data on hard disc

Automatic climate control: individually adjustable for all the seats

Integral seat: massage and ventilation for perfect comfort

The driver and vehicle form a perfect team in the interior of the new CL-Class. This is made possible by a newly developed control concept adopted from the S-Class, which is based on extensive ergonomic and perceptual psychology studies, and takes into account the findings from many months of acceptance testing conducted with Mercedes customers all over the world.

The key aims in the development of the operating system for the new S-Class were adaptation and integration, i.e. tailoring technology to the needs of people as effectively as possible (adaptation) in order to optimise safety and enhance comfort, and ensuring clearly and logically arranged controls (integration).

Mercedes engineers have moved the infrequently used seat and climate control adjustment functions, which were operated using separate switches or buttons in the outgoing model, into the central control system COMAND. The Sindelfingen-based experts have grouped together other functions, for which switches and buttons are still the most effective solution, into functionally related control clusters. These control clusters can be found in the door trim, instrument panel and roof lining. The principle behind the modifications is "everything in its place".

Rapid access to frequently used functions is a major characteristic of the intelligent control system in the S-Class. This means that the driver is not required to relearn, is able to retain old habits and feels at home immediately. The control system is designed for redundancy: the radio, TV receiver, CD/DVD changer, telephone and navigation system can be accessed either via the new COMAND controller and its menu structure, or directly using buttons. The relevant control buttons are ergonomically located in front of the controller, so that the driver can operate them by feel without having to look down. The "Return" button takes the driver back to the next-higher menu level.

The buttons and controls on both sides of the COMAND controller are just as easily accessible. The buttons on the right switch the system on or off, regulate the sound volume or activate the mute function, while the switch array on the left allows the driver to select the transmission mode and adjust the rear head restraints. As another special feature, there is also an individually programmable button for specific functions chosen by the driver. It can be programmed to operate the rear window blind, activate the interior monitoring and tow-away protection system or repeat the route recommendations given by the navigation system, for example.

Operation of the standard automatic climate control system is also possible in two ways, i.e. on a redundancy basis: using the COMAND controller and menu-based control via the colour display, or by means of an attractively styled switch array beneath the air vents. The COMAND system allows further individual climate adjustments such as air distribution and footwell adjustment.

The new functions which are now also controlled via COMAND include individual adjustment of the standard lumbar supports and multicontour seats (see page 59). The display shows a photo-quality image of the seat with the different air cushions highlighted in colour. These can be individually selected using the controller, then adjusted as required. As before, all other seat adjustments and functions are grouped into clearly arranged control clusters in the doors.

Colour cockpit display with clear menu-controlled functions

The steering wheel and instrument cluster are the primary areas in the newly developed control system. These integrate all the important information and functions required by the driver. The centrepiece is an eight-inch (16 : 9) high-resolution colour display with the latest TFT (Thin Film Transistor) technology for an impressively clear image. There is a graphically animated dial speedometer whose needle is partially overlapped to highlight the information presented by the central display. The graphics computer generates a text bar on the lower edge of the TFT display, where up to seven main menus – depending on the equipment levels specified and – and various sub-menus governing individual settings, displays and control functions can be accessed:

Trip	Odometer and trip recorder, trip computer, range, digital speedometer.
Navi	Directional instructions (indicated by arrows) by the navigation system.
Audio	Radio programme, TV programme, title display for CD player, CD-changer and video DVD.
Telephone	Number dialled, caller number, telephone directory.
Assistance	Distance display for DISTRONIC, proximity warning, settings for reversing camera.
Service	Tyre pressure control, ASSYST PLUS, messages.
Settings	Daytime driving lights, digital secondary speedometer, SPEEDTRONIC, activation of radar sensors.

Five-way buttons on the steering wheel

For rapid selection of these functions Mercedes-Benz has developed the controls on the standard multifunction steering wheel further, using circular, illuminated five-way buttons which the driver operates by light thumb pressure. The relevant selection or setting is confirmed by pressing the "OK" button at the centre of the disc. A separate "Return" button enables the driver to return to the next-higher menu level immediately.

The five-way button on the right of the multifunction steering wheel is used to regulate the sound volume (vertical) and operate the car phone (horizontal). Below this there is an additional button with which the driver can activate the LINGUATRONIC voice control system (optional). A few verbal commands are then enough to operate the car phone, audio equipment and navigation system.

COMAND: screen in the driver’s line of vision

The successful Cockpit Management and Data System – COMAND for short – has undergone further technical development with enhanced styling. The result is a considerable increase in its capabilities. In addition to the familiar telematics and audio units, Mercedes engineers have now integrated various vehicle functions which previously required individual controls. Two new features are immediately obvious:

The large eight-inch 16:9 colour display, which is now positioned at the same level as the instrument cluster and is therefore even more visible to the driver and front passenger. The display can also be electrically pivoted to the left or right by ten degrees.
The new aluminium COMAND controller with the handrest trimmed in fine wood (CL 600) or leather (CL 500), which serves as the mechanical and electronic interface between the front occupants and COMAND. The main and sub-menus for the control system are selected by rotating or nudging the controller, which is then pressed to confirm the relevant function. A geared electric motor assists the movements of the controller and provides tactile feedback. The rotary function is automatically locked when the end of a display sequence has been reached, for example. If a car phone is fitted ex factory, the handrest can be flipped up to reveal the telephone keypad.

A new operating structure, up-to-date colours and clear, photo-quality graphics also make the COMAND menu selection procedure a gratifying visual experience. The screen content is horizontally divided into separate areas which are easily accessed using the controller. As in the central display in the instrument cluster, the system is accessed via a menu bar which contains up to five main functions:

Navi	Road map, destination input, destination memory.
Audio	Radio, CD player or changer, DVD audio, MP3, rear entertainment (optional), auxiliary port.
Tel	Telephone, address book, news.
Video	TV reception, DVD video, auxiliary port.
Vehicle	Rear blind, exterior mirrors (convenience settings), easy entry and exit (steering wheel), headlamp switch-off delay, ambient lighting (optional), locator lighting, automatic locking, interior monitoring, tow-away protection, boot lid stop.

Calling up one of the menus activates further menu bars on the lower edge of the COMAND display. When the radio is switched on, for example, these allow additional settings to be accessed, including sound, balance/fader, waveband and a list of stations. The newly designed radio dial clearly displays radio stations, which the driver or front passenger can change by rotating the controller. The usage principle behind the menus is straightforward and easy to get to grips with: functions or lists arranged under the sub-menus are called up by pressing the controller, while elements within the lists are activated by turning the controller or nudging it up or down, then pressing it. To close one of the lists, it is sufficient to move the controller to the side or press the "Return" button in front of the controller.

A radio, CD player and PC card player in one

The COMAND system in the CL-Class combines the latest audio, video and navigation technology. The following functions are included in the standard configuration:

Radio	SW, MW, LW and FM reception. Twin FM tuner with RDS/TMC. Automatic station memory for all receivable radio programmes. 20 station memory presets per waveband.
Amplifier	Four x 25 watts. Ten loudspeakers.
CD/DVD	Single deck for music CDs and for audio or video DVDs. Also for MP3 formats.
PC cards	Slot for PCMCIA cards below the CD/DVD player.

Navigation data on a computer hard disc

COMAND can be ordered with a navigation system as an option (standard for CL 600). In addition to the satellite receiver (Global Positioning System) and yaw-rate sensor, this system also contains a 20-gigabyte hard drive, which allows impressively high-speed access to navigation data and even quicker route planning than with a DVD-based navigation system. During the route guidance procedure, the navigation system provides even more precise information than ever and recommends which lane the driver should get into on a motorway, for example. Audible traffic congestion reports are also an option, meaning that the driver no longer has to read this information on the display and can therefore focus more effectively on what's happening on the road ahead.

Sound experience based on the latest digital audio technology

The sound system developed specially for the new Mercedes-Benz S-Class is also available as an option for the luxury Coupé. It offers a live-concert-quality musical experience. Mercedes-Benz sound engineers joined forces with audio experts harman/kardon® to introduce technology never before seen in a car and create a whole new three-dimensional sound experience. The system delivers a previously inconceivable, natural 360-degree musical experience for all passengers, whether from a DVD or CD source and from 5.1 surround or normal stereo recordings. The musical signals are distributed via a 600-watt amplifier located in the rear of the Coupé.

Among the factors influencing sound quality are not only signal processing and transmission, but also special, innovative metal matrix loudspeakers. The rigidity-to-weight ratio of their sophisticated membranes is three times greater than conventional loudspeakers. This gives them extra sensitivity.

Dimensional concept: comfort made to measure

As with the control system, Mercedes engineers followed a clear principle when developing the dimensional concept for the interior: the car had to adapt to the people inside it, rather than vice versa. With this aim in mind, they developed an interior whose spaciousness and ergonomics are rooted in scientific research findings. The result for the occupants is an outstanding feeling of space, freedom of movement and long-distance comfort. The new flagship Coupé by Mercedes-Benz is slightly larger than its predecessor: with a length of 5065 millimetres, a width of 1871 millimetres and a height of 1418 millimetres, the body is 75 millimetres longer, 14 millimetres wider and 20 millimetres higher than before. The boot capacity has increased by 40 litres to 490 litres (acc. to VDA measuring method).

Passengers in the new CL-Class thus benefit from even greater spaciousness: elbow room for the driver and front passenger has increased by 54 millimetres, and shoulder room in the rear by 16 millimetres.

10: Interior (II)

Interior (II)

Seats: wellness on wheels

With individually adaptable backrest and cushion contours, active ventilation and an innovative massage function, the integral seats of the new Mercedes-Benz CL-Class increase the personal wellbeing of the occupants on long journeys. The seal of approval by an independent jury representing "Aktion Gesunder Rücken", a German organisation which tests products for spine-friendly design, confirms the high quality of the newly developed multicontour seat and its health-promoting effects.

The front seats of the CL-Class are designed as so-called integral seats. All the components of the seat belt system are mounted directly on the seat: the inertia-reel mechanism with belt force limiter, automatic comfort-fit, belt buckle and the upper reversing point for the belt. This ensures that the seat belt is in the best possible position for any seat adjustment, and can therefore carry out its protective function to best effect. Accordingly the seats are important components of the occupant protection system. Thanks to robust seat rails of extruded aluminium sections and their sophisticated, weight-optimised welded construction using high-strength steel, they are able to withstand even the most extreme forces during a crash.

Even the newly developed standard seat provides the driver and front passenger with first-class comfort. The fore-and-aft position, backrest and cushion angle, seat height, head restraint and seat cushion depth are electrically adjustable – independently and variably, so that each occupant is able to choose the best individual seating position. This also applies to comfort and support for the lower back, as pneumatic lumbar supports are also standard equipment for the front seats. These enable the driver and front passenger to adapt the backrest contours to their own anatomy, relieving stress on the back muscles.

The technical construction of the newly developed seats for the CL-Class meets the traditionally high standards of quality maintained by the Mercedes-Benz brand in this area. This means sinus springs with a polyurethane foam pad in the seat cushion and Pullmaflex suspension padding with a breathable natural fibre/rubberised mat in the backrest.

Active seat ventilation even more effective

The seat development specialists at Mercedes are not only concerned with classic comfort characteristics such as the springs and padding, but also with the all-round wellbeing of the car’s occupants. The materials and structure of a Mercedes seat must ensure comfort in all weather and temperature conditions. This is ensured by breathable materials and the high-quality leather upholstery used for CL-Class seats.

Even more climatic comfort is provided by actively ventilated luxury seats, which are standard equipment in the CL 600: miniature fans in the seat cushion and backrest take in cool air at floor level and evenly distribute this via an air-permeable fabric under the surface of the seat. This gentle airflow ensures that the occupants remain cool and comfortable even at high outside temperatures.

Specialists have now improved this technology even further. The heated, actively ventilated luxury seats in the new CL-Class are equipped with even more efficient fan controllers, which regulate likewise improved mini-fans in the seat cushion (4) and backrest (2) of each front seat. The upholstery materials have also been modified to improve the efficiency of the heating and ventilation functions even further. The heating elements are now located directly beneath the seat covers.

New multicontour seat with two additional air chambers

Like active seat ventilation, the multicontour seat is a very successful Mercedes invention which greatly contributes to the high level of long-distance comfort in cars bearing the Mercedes star. Multicontour means that the occupants are able to adapt the contours of the seat to their individual anatomical or comfort requirements. This is made possible by air chambers within the seat padding.

A new-generation multicontour seat is used in the CL-Class. This has even more functions – and therefore provides even greater comfort. While the previous multicontour seat featured seven air chambers, the driver and front passenger are now able to adjust four zones in their seats with the help of nine air chambers. These are ...

the two side bolsters of the seat cushion;
the lumbar support, which is also height-adjustable;
the two side bolsters of the seat backrest;
the shoulder support.

Thanks to new piezo valves, the pneumatics of the multicontour system operate even more quietly and precisely than before. Moreover, the valves are now in a decentralised configuration and therefore respond more rapidly, which means that for the first time, the multicontour seats can also be integrated into the PRE-SAFE® anticipatory occupant protection system: if PRE-SAFE® detects the risk of a collision, it not only tensions the front seat belts but also inflates the air chambers in the side bolsters of the seat cushions and backrests as a precaution. These bolsters enclose and support the occupants, also increasing the distance to the interior door panels during an impact and enabling the sidebag to fulfil its protective function more effectively.

Lateral support tailored to the driving situation

Customers can enjoy the ultimate in seat comfort by specifying the dynamic variant of the multicontour seat for the new CL-Class (standard in the CL 600). The new, decentralised piezo valves for the air chambers noticeably improve the dynamic function of the multicontour seat by responding more rapidly to steering movements. The pressure and volume of the side air chambers in the seat backrests are adjusted in a matter of seconds according to the steering angle, lateral acceleration and speed of the car in order to offer the driver and front passenger even better lateral support. The chambers respond to the driving situation in hand, the system pumping more air into the chambers on the right-hand side of the backrest in left-hand corners, for example, while the left-hand chambers are given extra air through right-hand bends. This dynamic multicontour function relieves stress on the muscles and thus promotes physical wellbeing.

Separate air chambers for a relaxing back massage

The massage function for the dynamic multicontour seat is also a completely new development by Mercedes specialists. This no longer makes use of the air chambers with which the seat contours are adjusted, but rather a separate package of air chambers which is directly integrated into the seat padding. This means that the individual comfort settings are retained.

A micro-computer controls the seven separate massage air chambers. This inflates and empties the air chambers according to a fixed programme, which passengers in the new CL-Class perceive as a pleasant, pulsing motion across the entire back. This stimulates the muscles, improves the circulation and helps to prevent early fatigue. The massage programme lasts for five minutes and can be restarted at any time once the cycle has finished. The intensity and speed of the massage function can also be individually adjusted, from "slow and gentle" to "fast and powerful".

Climate control: four temperature zones for individual comfort

The numerous series of tests conducted by the passenger car development department at Mercedes-Benz and DaimlerChrysler Research provide clear evidence that a high-performance air conditioning system is one of the most important elements in keeping a driver alert and focused during long journeys. A driver's powers of concentration and reactions are influenced critically by the climate inside the vehicle.

The automatic climate control system of the new CL-Class is based on the system used in the S-Class since autumn 2005, and meets the highest standards. Each passenger can adjust the temperature in their area of the car individually, the system working according to a new concept based on four independently controlled temperature zones. The engineers refer to upper and lower temperature zones:

The two lower zones correspond to the air vents in the front and rear footwells and the two central vents in the rear.
The upper temperature zones include the vents in the centre of the dashboard and the defroster outlets on the driver's and front passenger sides of the car.

Whereas conventional air conditioning systems work according to pre-programmed stratification of head and footwell temperatures, the new zone concept in the new CL-Class now allows continuous adjustment of the temperature stratification inside the car. Flaps in the climate control unit are responsible for regulating the temperature in the four zones, ensuring a mixture of cold and warm air and thus controlling the desired airflow temperatures. A total of 15 electric motors control these cold and warm-air flaps in the mixture zones, and the air outlet flaps for the vents.

Personalised settings are also possible in automatic mode

The automatic climate control system also offers a range of other individual adjustment options, which the driver and front passenger can select using the COMAND controller and the COMAND display. One example is the footwell temperature. The system features five settings which can be selected to raise the outflow temperature specifically in the footwell area.

Since the definition of what constitutes climatic comfort is highly subjective, even in automatic mode the system in the new CL-Class works according to individual settings and preferences. In addition to individually adjustable footwell heating, there are three different types of ventilation to choose from, which the driver and front passenger can select using the COMAND controller:

Medium airflow: This setting is equivalent to the previous automatic mode in a Mercedes air conditioning system.
Diffuse airflow: This mode delivers the lightest possible airflow. The cooled or warmed air is not channelled directly towards the passengers, but flows predominantly out of the defroster vents in the dashboard, the air outlets in the footwells and from the direct ventilation level.
Focused airflow: In this setting, the automatic climate control pushes out larger quantities of air and channels it mainly through the vents in the direct ventilation level.

In the interests of raising individual comfort levels still further, the air conditioning system in the new CL-Class now allows the driver and passengers to adjust the quantity of air separately for the left and right-hand sides of the car, as well as the temperature and air distribution. They can do this at the touch of a button on the attractively styled dashboard control panel, or by going into the climate control menu bar on the COMAND display.

Sensors for temperature, humidity, solar radiation and pollutants

The system is controlled by a total of eight climate control sensors. As well as outflow temperature sensors in the four temperature zones, the central temperature sensor next to the ignition switch, the solar sensor and the evaporator sensor, the automatic climate control system also uses a special dew point sensor to respond to changes in humidity. Working in conjunction with the fully variable refrigerant compressor, this humidity sensor allows the system to respond as required. Intake air is first cooled according to its humidity, then dried and heated to the desired temperature. The air conditioning system works far more efficiently than conventional systems and offers higher levels of comfort.

In addition, the automatic climate control in the new CL-Class is fitted with a pollutant sensor, which measures the amount of carbon monoxide and nitrogen oxide in the outside air. If pollutant concentrations rise beyond a certain level, the air conditioning system switches automatically to recirculation mode. In fresh-air mode, two combined filters arranged in a "V" are permanently in use. These absorb pollutants, separate out plant pollen and dust particles and reduce irritation for the passengers caused by odours.

Interior lighting: pleasant ambient lighting during the journey

Light is synonymous with safety, but it also influences comfort. The Mercedes engineers took both aspects into account in the development of the interior lighting system for the new CL-Class. In order to ensure that the occupants feel as comfortable in darkness as during the day, the switches and controls benefit from indirect lighting, and the footwells and door handle recesses feature lamps which give off a pleasant amber light. This helps to create a pleasant ambience during the journey. An LED in the rear-view mirror casing also contributes to the interior lighting and is directed towards the centre console.

The diffuse light for the front of the car has five dimmer settings and can be adjusted individually using the buttons on the multifunction steering wheel and the central display in the instrument cluster. The brightness of the front and rear footwell lighting automatically dims when the doors are closed.

Mercedes-Benz is offering a special optional extra (standard in the CL 600) which makes night driving in the CL-Class even more of a special experience: indirectly illuminated wood trim elements in the doors and dashboard. Thin optical fibres located behind the trim strips and illuminated by LEDs generate a harmonious and continuous band of light below the waistline, improving orientation for the passengers and at the same time enhancing comfort and the feeling of spaciousness. The brightness of this ambient lighting can be individually adjusted and is automatically activated as soon as the doors are closed.

11: Chassis

Chassis

Active Body Control: second-generation system with even more capabilities

Axles and steering: further development of well-proven technology

ADAPTIVE BRAKE: New braking system with support functions

In 1999, with the introduction of the predecessor to the new CL-Class, Mercedes-Benz opened up new dimensions in handling dynamics: the flagship Coupé was the world’s first car to feature the Active Body Control (ABC) suspension system. This innovative system has been developed and improved even further for the new CL-Class.

Active Body Control resolves the traditional conflict of aims when configuring a passenger car suspension: should wheel vibrations caused by the road surface be kept to a minimum by a sports, stiff shock absorber configuration, or should the damping be made more comfortable and soft at the expense of handling safety and performance? Thanks to ABC, which is standard equipment in the new CL-Class, this conflict of aims is a thing of the past: the suspension configuration is automatically adapted to suit the current driving situation. A high level of comfort is accompanied by dynamic performance - or vice versa.

To this end, the four spring struts are equipped with microprocessor-controlled plunger cylinders which almost completely compensate yawing, pitching and rolling movements of the vehicle body. The computer receives information about the relevant driving situation from the various acceleration sensors, then compares this with the data from the pressure sensors in the spring struts and the level sensors in the steering control arms. The ABC system translates this information into control signals, which are implemented as precisely metered oil flows by hydraulic servo-valves on the front and rear axles. When oil flows into the plunger cylinders, these adjust the tracing point of the steel springs integrated into the spring struts, generating the forces necessary to counteract movements of the vehicle body.

Under pressure: body is stabilised within fractions of a second

Owing to the constantly available hydraulic pressure of up to 200 bar, ABC is able to stabilise the vehicle body immediately - in fractions of a second. The system operates in the vibration range up to five hertz, the range which causes pitching and rolling movements on uneven road surfaces, side-roll on bends and the typical body dive experienced during braking. Higher-frequency vibrations and wheel damping are the responsibility of passive twin-tube gas-pressure shock absorbers, which can be configured for excellent comfort.

Every component in the active suspension control system has been revised for the new CL-Class. The specialists have now arranged various components into groups, in order to improve the control functions with shorter connecting lines and reduce the installation space required.

On fast bends: body roll reduced by up to 45 percent

The major advantage of second-generation Active Body Control is its greater efficiency in reducing body movements according to the driving situation: the body roll angle during a dynamic driving manoeuvre is reduced by more than 45 percent – from the previous 2.2 to 1.2 degrees. When taking bends at speed – for example when leaving a motorway – this second-generation ABC suspension reduces the roll angle to just 0.7 degrees.

Other special features of Active Body Control include variable anti-roll control between the front and rear axles, which the system carries out automatically as a function of vehicle speed to combine agile handling with outstanding stability. The system also takes the vehicle load into account: on the basis of the plunger and spring travel, the ABC computer calculates the actual vehicle weight and takes it into consideration for the active control function.

At the touch of a button: individual suspension and transmission characteristics

In addition the new CL-Class features an S/C/M button in the centre console with which the driver is able to modify the overall characteristics of the Coupé from "comfortable" to "sporty":

Comfort: In this mode the automatic transmission changes the gears at lower engine speeds, and the CL Coupé moves off in second gear. The ABC suspension operates in Comfort mode, comfortably smoothing out uneven road surfaces and bumps.
Sport: The automatic transmission makes full use of the engine speed range in this setting. The ABC suspension operates in Sport mode, with a stiffer damping effect on uneven surfaces and bumps. The characteristic map of the accelerator is also modified, so that the engine responds more rapidly when acceleration is required.
Manual: The automatic transmission is operated manually using gearshift buttons on the steering wheel, with significantly reduced gearshift times compared to "Sport" mode. The suspension configuration selected by Active Body Control is the same as in Sport mode, as is the characteristic map of the accelerator.

If the CL-Class is travelling on poor roads which make a higher ground clearance advisable, the driver is able to raise the suspension by 45 millimetres at the touch of a button. When travelling at high speed in Sport mode, ABC automatically lowers the suspension by up to ten millimetres to reduce aerodynamic drag and lower the fuel consumption.

Front axle: four-link technology improved even further

In addition to improving the ABC system, the Mercedes development engineers turned their attention to the choice of axle designs for the new luxury Coupé. The results of digital design and test procedures, as well as exhaustive practical trials, confirmed them in their view that four-link technology offers the greatest advantages for the front axle. Accordingly this was refined in detail – especially where comfort is concerned.

Wheel location at the front is by means of a so-called high-link axle. This consists of an aluminium wishbone at the upper level, a lower aluminium torque strut and a spring link of forged steel. The two levels are connected by steering knuckles. The fourth component, the one that gives the four-link axle its name, is the track rod; this creates the link between the front wheels and the transverse rack-and-pinion steering system.

Another major advantage of the Mercedes four-link axle is the design of the lower link level. This provides favourable axle kinematics, and is almost completely insensitive to vibrations caused by unbalanced tyres or fluctuations in braking force. It was on this positive basis that the engineers reconfigured the kinematics and elasto-kinematics of the new CL-Class, with a great improvement over the preceding series. Safety specialists at the Mercedes-Benz Technology Centre provided another important reason for choosing the four-link system: in a frontal crash it offers longer deformation paths at the lower link level than other axle designs, and is therefore able to absorb kinetic energy more efficiently.

Compared to the preceding model, the wider track (front + 24, rear + 29 millimetres) and the longer wheelbase (+ 70 millimetres) create other important conditions for the even better ride comfort and exemplary handling dynamics of the new CL-Class. The figures at a glance:

Wheelbase mm	2955
Track front mm	1601
Track rear mm	1607

Steering: mid-centred for safe, stable handling

As before, the steering gear is located in front of the wheel centre and therefore supports the easily controlled understeer characteristic of the luxury Mercedes Coupé on bends. The servo-assisted rack-and-pinion steering has a variable ratio (50.1 to 60.5 millimetres per turn of the wheel), which is slightly more indirect in the mid-range than in the outer positions. The lower the vehicle speed, the greater the servo-assistance: below 200 km/h the steering effort is continuously reduced depending on speed, which means that the driver only needs to exert one third of the maximum steering effort when parking at low speed.

Variable mid-centring is a new feature in the CL-Class: the electrohydraulic, speed-sensitive servo valve is used to create a centring force which increases with the vehicle speed and gives the driver a feeling of safety and stability in the centre position. This additional steering force is not activated when the vehicle is at a standstill, enabling the advantages of the speed-sensitive steering to be fully exploited.

The telescopic steering column is electrically adjustable for height and reach, and also provides an automatic entry/exit aid as an additional convenience feature: once the driver has withdrawn the electronic ignition key, the steering wheel moves upwards to provide more legroom. The wheel then remains in this position until the key is reinserted into the ignition lock, when it returns to its preset position.

Mercedes-Benz has developed a four-spoke steering wheel with a diameter of 390 millimetres for the new CL-Class, whose diecast magnesium structure specifically deforms during a frontal impact to reduce the risk of injury to the driver. With its ergonomically located, illuminated control buttons, the steering wheel is a major component of the operating system in the new CL-Class. An electrically heated steering wheel is available on request.

Rear axle: made completely from aluminium

Because multi-link axle technology remains unsurpassed, the engineers at Mercedes have remained faithful to it in the new CL-Class, but have made certain detailed improvements: the rear axle housing is derived from the previous unit as an aluminium construction which is open to the front and features a bolted front cross-member. The major advantages of this new sub-assembly are lower weight, greater strength and more compact dimensions.

The use of uncompromising lightweight construction methods has enabled Mercedes engineers to reduce the weight of unsprung masses at the rear axle considerably, thereby improving both handling and ride comfort. Four of the five links are of forged aluminium, while the spring link is of single-skin sheet aluminium and the wheel carrier is of diecast aluminium. The rigidity of the wheel-locating components has also been increased.

The specialists in Sindelfingen also gave their attention to insulating vibrations which might be transmitted from the final-drive unit to the vehicle interior via the axle housing. Three large rubber bearings were developed to minimise this effect.

Braking system: high-tech for outstanding safety and comfort

ADAPTIVE BRAKE – this newly developed braking system familiar from the S-Class is also standard equipment in the new CL Coupé. It allows electronic control of the hydraulic, dual-circuit braking system and provides a number of support functions for additional safety and comfort:

HOLD: Once the luxury Coupé has been braked to a stop, briefly depressing the brake pedal a little further activates this function. The CL-Class is then held in position by the brakes – even when the driver removes his foot from the brake pedal. In this way the HOLD function prevents the vehicle from rolling forward unintentionally at traffic lights or in stop-and-go traffic.
Hill holder: With this auxiliary function, ADAPTIVE BRAKE prevents the CL-Class from rolling backwards when the driver switches from the brake pedal to the accelerator to move off on an uphill gradient. When the sensor system detects that the Coupé has come to a stop on a gradient, the hill holder function is activated automatically and maintains a constant brake pressure for a short time to make moving off easier.
Priming: The braking system interprets rapid removal of the driver’s foot from the accelerator as an emergency braking situation. In this case ADAPTIVE BRAKE increases the pressure in the brake lines and brings the brake linings into light contact with the brake discs, so that they are then able to bite immediately and with full force when the brake pedal is depressed. In this way the system supports the functions of Brake Assist and Brake Assist PLUS.
Brake drying: In the wet ADAPTIVE BRAKE applies regular, brief braking impulses to wipe the film of water from the brake discs and ensure that the brakes are able to perform at their peak. The automatic brake drying function is always activated when the windscreen wipers of the CL-Class have been operating for a certain time. The driver does not notice the finely metered braking impulses.

Large-diameter front and rear brake discs create the technical basis for reliable deceleration with ADAPTIVE BRAKE. Depending on the engine version, their diameter is up to 360 millimetres at the front and up to 330 millimetres at the rear. The front brake discs are perforated. The perforations conduct water and dirt away, ensuring that the brakes operate reliably and with good deceleration performance in poor weather conditions. The figures at a glance:

Front axle	CL 500	CL 600
Callipers Lining area Discs Diameter Thickness	4-piston fixed callipers 2 x 77 sq. cm Int. ventilated, perforated 350 mm 32 mm	6-piston fixed callipers 4 x 120 sq. cm Int. ventilated, perforated 360 mm 36 mm
Rear axle
Callipers Lining area Discs Diameter Thickness	1-piston floating calliper 2 x 38 sq. cm Internally ventilated 320 mm 24 mm	4-piston fixed calliper 2 x 48 sq. cm Internally ventilated 330 mm 26 mm

Parking brake: electric motor for added convenience

The new CL-Class is equipped with an outstandingly convenient, electric parking brake as standard. The brake is activated by simply pressing a button on the dashboard. The brake is automatically released as soon as the driver selects a gear and moves off. The major components of this new development are two separate servo drum brakes at the rear wheels and an electric motor with a reduction gear, which applies the brake drums by means of cables. The electric parking brake can also be applied when the engine is switched off.

Dynamic safety systems: new functions for even better performance

ABS, ASR, ESP®, Brake Assist – these well-proven dynamic safety systems developed by Mercedes-Benz are standard equipment in the new CL-Class, and now have a number of additional functions.

Mercedes engineers have enhanced the anti-lock braking system (ABS) with additional technology that makes braking even safer on surfaces which are slippery on one side. The system recognises these situations and controls the brake pressure in such a way that the driver is given optimal assistance in staying on track and braking efficiently. The ABS system in the new CL-Class also ensures more safety when braking on bends, as it distributes the braking forces to create a yawing moment which counteracts and stabilises the vehicle’s tendency to break away. The braking system uses data supplied by the ESP® sensors to detect these situations reliably.

The Electronic Stability Program also improves the functions of acceleration skid control (ASR): ESP® sensors supply online information about the slip at each wheel and enable the traction control to be activated even more precisely, particularly allowing much better progress on icy roads. What is termed “snow-chain logic” is another enhanced ASR function. On the basis of the drive torque and driving resistance, this system automatically detects whether snow-chains have been fitted and adapts the acceleration skid control accordingly.

When taking fast bends, a yaw moment control system now registers the stiffness of the tyres and improves ESP® control intervention if the CL-Class is fitted with winter tyres. The new, electronically controlled braking system ADAPTIVE BRAKE offers additional advantages because the brake servo unit is selectively controlled by electronic means, allowing ESP® to operate particularly sensitively and comfortably. The system is also faster and more efficient than before: ESP® automatically reduces the distance between the brake pad and the brake disc if there is a risk of skidding and the CL-Class needs to be stabilised by specific braking impulses.

Tyre pressure loss warning as standard

Tyre pressures are monitored by the Electronic Stability Program ESP® or a special control system based on radio technology:

ESP® continuously compares the wheel rotation speeds, which mainly depend on the vehicle speed, vehicle load and tyre pressures. In addition the control unit automatically monitors other dynamic parameters such as the lateral acceleration, yaw rate and wheel torque in order to diagnose any pressure loss in a tyre reliably. It is therefore able to detect any significant deviations and inform the driver via the central display: "Tyre pressure, check tyres". This tyre pressure loss warning system based on ESP® technology is standard equipment in the CL-Class.
An optional electronic tyre pressure monitoring system is also available; it uses sensors in the tyre valves to monitor both the air pressure and temperature inside the tyre. The data are transmitted by radio to a special underfloor aerial at regular intervals. Intelligent software is used to identify the wheel positions automatically, so that the driver can be given specific information about the air pressure in each tyre via the central display.

To ensure continued mobility in the event of a flat tyre, Mercedes-Benz also offers run-flat tyres as an optional extra. These have self-supporting walls, and enable Mercedes customers to continue for a distance of up to 100 kilometres at a maximum speed of 80 km/h despite the flat tyre.

12: Engines

Engines

New V8engine with 285 kW/388 hp and high-tech features

Up to 26 percent more output and 15 percent more torque

Seven-speed automatic transmission with three shift modes

The new CL-Class is equipped with the most powerful Mercedes engines: the eight-cylinder unit in the CL 500 is a new development which celebrated its debut in the S-Class in autumn 2005, while the Stuttgart engineers have developed the biturbo V12 unit of the CL 600 further to generate 12 kW/17 hp more output and 30 Newton metres more torque than before. In specific terms this means 380 kW/517 hp and 830 Newton metres in an engine speed range of 1900 to 3500 rpm. Despite this higher output, the V12 engine consumes 0.4 litres less fuel per 100 kilometres than the previous CL 600.

The new eight-cylinder unit in the CL 500 develops 285 kW/388 hp from a displacement of 5.5 litres, an increase of more than 26 percent versus the previous V8. At 530 Newton metres the torque also comfortably exceeds the maximum for the preceding engine by around 15 percent. This high level of torque is available from 2800 rpm and remains constant throughout a wide engine speed range up to 4800 rpm, providing ideal conditions for powerful acceleration and fast intermediate sprints.

With a specific fuel consumption of 233 grams per kilowatt hour (g/kWh) at peak efficiency and 345 g/kWh at part-throttle (2000 rpm, 2 bar), this engine is easily the most fuel-efficient unit in this displacement and output class.

Key data for the CL engines at a glance:

	CL 500	CL 600
Cylinder arrangement/ valves per cylinder	V8/4	V12/3
Displacement cc	5461	5514
Bore/stroke mm	98.0/90.5	82.0/87.0
Compression ratio	10.7 : 1	9.0 : 1
Output kW/hp	285/388	380/517
Max. torque Nm at rpm	530 2800-4800	830 1900-3500
Fuel consumption combined l/100 km	12.1	14.3
Accel. 0-100 km/h s 60-120 km/h s	5.4 5.9	4.6 4.8
Top speed km/h*	250	250

*Electronically limited

Lightweight construction for smooth running and dynamic agility

A crankcase of diecast aluminium with low-friction aluminium/silicon cylinder liners is the solid and durable core of the new Mercedes-Benz eight-cylinder engine. It houses a five-bearing, forged steel crankshaft with induction-hardened main and big-end bearings. The connecting rods are also of forged steel, with specific areas milled away to make them around one fifth lighter than those of the previous V8 engine in the CL-Class.

Saving weight was not the only important aspect during the design work on the new engine, however. The engineers were just as determined to achieve the best possible results where smooth running and flexibility are concerned. Lightweight construction principles were helpful in this respect, for the lower the moving masses in the crankcase, the lower the vibrations and the more responsive the engine is to movements of the accelerator pedal.

Shifting camshafts for a perfect charge cycle and higher torque

Mercedes engineers used an intelligent valve control system, achieving remarkable progress and a major contribution to the good performance characteristics and low fuel consumption of the unit. In addition to four-valve technology, continuously adjustable intake and exhaust camshafts ensure that the cylinders are optimally supplied with fresh mixture. The valves are opened at precisely the right moment in any driving situation, significantly improving the gas cycle in the combustion chambers and reducing energy losses.

The camshafts are controlled by electro-hydraulically operated vane-type adjusters, which are located at the forward ends of the camshafts and are controlled by four integral hydraulic valves. The intake camshafts are driven by a duplex chain, while the exhaust camshafts are directly driven by the intake camshafts via a braced pair of gears.

The engineers at Mercedes-Benz have optimised the effect of this four-fold, continuous camshaft adjustment by using what are known as shifting camshafts. These control the opening of the exhaust valves and improve the engine’s charge cycle even further. Depending on the ignition sequence, the exhaust cams are designed in such a way that the valves open at different times during the exhaust cycle. This reduces the pressure fluctuations in the exhaust tract which are inherent to a V8 engine, and which lead to fluctuations in the residual gas content in the cylinders. The valve lift interval on the exhaust sides of the Mercedes eight-cylinder engine is as follows:

Cylinder 3, 4, 5, 7: 180 degrees crankshaft with 2 mm valve lift
Cylinder 1, 2, 6, 8: 190 degrees crankshaft with 2 mm valve lift

The newly developed shifting camshafts improve the torque and smoothness of the V8 engine by ensuring a more uniform residual gas content, a higher knock limit and better cylinder charging in the lower to medium engine speed range. At 2000 rpm, for example, the effective mean pressure is around six percent (10.3 : 11.0 bar) higher than in a comparable engine without shifting camshafts.

Two-stage intake module and tumble flaps for better combustion

In addition, the V8 features further technical innovations for adaptive control of the combustion processes:

Two-stage intake module for a controlled air supply depending on the engine load and engine speed: the length of the intake ducts leading to the cylinders is varied by flaps. At high engine speeds – from approx. 3500 rpm - the flaps are open and the air flows directly to the combustion chambers. This allows high outputs to be achieved. At low engine speeds the flaps are closed to increase the length of the intake ducts. This creates pressure waves which support the intake process and improve the torque yield in the lower engine speed range. As a result 435 Newton metres of torque, and therefore more than 82 percent of the maximum torque, are already available from 1500 rpm.
Optimised airflow for the best possible engine aspiration. Mercedes engineers used highly sophisticated flow calculations to optimise the airflows in the eight-cylinder power unit. Particular attention was for instance paid to the airflow from the twin-chamber air filter, the housing of the hot film air mass sensor and the intake manifold.
Tumble flaps for more complete combustion: electro-pneumatically driven flaps at the end of each intake duct increase the turbulence of the air flow, which is thus more uniformly distributed in the combustion chambers. At part-throttle the tumble flaps pivot up, optimising the airflow and increasing the speed of combustion; under higher engine loads the tumble flaps are not required, and can be completely recessed into the intake manifold so as not to impede the intake process. The use of these tumble flaps has two positive effects in practical operation, namely smoother running and a reduction in fuel consumption by up to 0.2 litres per 100 kilometres, depending on engine speed.

Combustion of the fuel/air mixture is by means of a direct coil ignition system. The spark plugs project into the centre of each cylinder between the four valves, with the ignition coils located directly above them.

Electronically controlled thermostat for adaptive heat management

The developers of the new Mercedes eight-cylinder engine have also made a major contribution to fuel economy with a sophisticated heat management system. Coolant circulation is interrupted during the warm-up phase, for example, so that the engine reaches its normal operating temperature more rapidly. This in turn improves the oil flow and considerably reduces friction in the engine. When the engine is warm and under full load, the heat flows are directed in such a way that the engine oil and coolant are always at an optimal temperature. This is ensured by an innovative, logic-controlled thermostat which is active in all operating situations and adjusts the coolant temperature according to the style of driving and the prevailing conditions. This also enables the heat supply to the heater core to be controlled as needed.

Twin catalytic converters und linear oxygen sensors for low exhaust emis-sions

The emission control system of the new Mercedes eight-cylinder engine follows a two-stage concept and is therefore highly effective. In addition to in-engine measures such as continuous camshaft adjustment, adaptive combustion control by tumble flaps, internal exhaust gas recirculation and secondary air injection, which ensure low engine-out emissions, the new CL 500 is equipped with two close-coupled catalytic converters as standard. These consist of two individual monoliths or bricks, each of which is monitored by two oxygen sensors: a control sensor and a diagnostic sensor which analyses the exhaust flow in the gap between the two bricks.

This oxygen sensing is linear, which means that the oxygen sensors are already active immediately after a cold start, supplying information about the exhaust gas constituents for the electronic control unit of the V8 engine to process when controlling the warm-up phase. This enables the catalytic converters to reach their normal operating temperature more rapidly.

Thanks to its ultra-modern technology and efficient emission control system, the new eight-cylinder engine complies with the most stringent exhaust emission standards currently in force; it also has the potential to meet limits which are planned for the future.

Transmission: seven gears and three different modes for the CL 500

The eight-cylinder engine of the CL 500 is specified as standard with the 7G-TRONIC seven-speed automatic transmission, the only passenger car transmission of this type in the world. The V12 engine of the CL 600 is paired with a five-speed automatic transmission.

The conventional, centre-console-mounted automatic selector lever is replaced by a DIRECT SELECT shift lever on the steering column, which allows the driver to select the "P", "N", "R" and "D" positions by slight finger pressure. The commands are transmitted electronically by cable.

The S/C/M/ mode selector switch on the centre console allows the driver to choose between three different modes: Sport, Comfort and Manual. As well as the transmission characteristics, these modes also allow the characteristics of the accelerator pedal and the suspension (springing and damping) settings to be varied. In Manual mode, the driver changes gear using the steering-wheel gearshift buttons.

13: Specifications

Mercedes-Benz CL 500

Engine

No. of cylinders/arrangement		8/V, 4 valves per cylinder
Displacement	cc	5461
Bore x stroke	mm	98.0 x 90.5
Rated output	kW/hp	285/388 at 6000 rpm
Rated torque	Nm	530 at 2800-4800 rpm
Compression ratio		10.7 : 1
Mixture formation		Microprocessor-controlled petrol injection with hot-film air mass measurement

Power transfer

Drive

Standard drive

Transmission

Seven-speed automatic transmission

Ratios

Final drive

1st gear

2nd gear

3rd gear

4th gear

5th gear

6th gear

7th gear

Reverse

2.65

4.377

2.859

1.921

1.368

1.000

0.820

0.728

-3.416/-2.231

Chassis

Front axle	Four-link axle, Active Body Control suspension
Rear axle	Multi-link independent suspension with Active Body Control
Braking system	Internally ventilated disc brakes all-round, front discs perforated, electrically operated drum-type parking brake at the rear, ABS, Brake Assist, ESP^®
Steering	Speed-sensitive rack-and-pinion power steering with steering damper
Wheels	8 J x 17 ET 43
Tyres	235/55 R 17

Dimensions and weights

Wheelbase	mm	2955
Track front/rear	mm	1601/1607
Overall length	mm	5065
Overall width	mm	1871
Overall height	mm	1418
Turning circle	m	11.6
Boot capacity*	l	490
Kerb weight acc. to EC**	kg	1995
Payload (at kerb weight acc. to EC)	kg	515
Gross vehicle weight	kg	2510
Tank capacity/reserve	l	90/11

Performance and fuel consumption

Acceleration 0-100 km/h Acceleration 60-120 km/h	s s	5.4 5.9
Top speed	km/h	250
Fuel consumption***	l/100 km	12.1

*Acc. to VDA measuring method; **Incl. 75 kg for driver and luggage; ***Combined

Mercedes-Benz CL 600

Engine

No. of cylinders/arrangement		12/V, 3 valves per cylinder
Displacement	cc	5513
Bore x stroke	mm	82 x 87
Rated output	kW/hp	380/517 at 5000 rpm
Rated torque	Nm	830 at 1900-3500 rpm
Compression ratio		9.0 : 1
Mixture formation		Microprocessor-controlled petrol injection with hot-film air mass measurement, biturbo system

Power transfer

Drive

Standard drive

Transmission

Five-speed automatic transmission

Ratios

Final drive

1st gear

2nd gear

3rd gear

4th gear

5th gear

Reverse

2.65

3.60

2.19

1.41

1.0

0.83

-3.17/-1.93

Chassis

Front axle	Four-link axle, Active Body Control suspension
Rear axle	Multi-link independent suspension with Active Body Control
Braking system	Internally ventilated disc brakes all-round, front discs perforated, electrically operated drum-type parking brake at the rear, ABS, Brake Assist, ESP^®
Steering	Speed-sensitive rack-and-pinion power steering with steering damper
Wheels	Front: 8.5 J x 18 ET 43; rear: 9.5 J x 18 ET 43
Tyres	Front: 255/45 R 18; rear: 275/45 R 18

Dimensions and weights

Wheelbase	mm	2955
Track front/rear	mm	1601/1607
Overall length	mm	5065
Overall width	mm	1871
Overall height	mm	1419
Turning circle	m	11.6
Boot capacity*	l	490
Kerb weight acc. to EC**	kg	2185
Payload (at kerb weight acc. to EC)	kg	435
Gross vehicle weight	kg	2620
Tank capacity/reserve	l	90/11

Performance and fuel consumption

Acceleration 0-100 km/h Acceleration 60-120 km/h	s s	4.6 4.8
Top speed	km/h	250 (limited)
Fuel consumption***	l/100 km	14.3

*Acc. to VDA measuring method; **Incl. 75 kg for driver and luggage; ***Combined

Auto Car Magazine

Blog Archive

Saturday, December 22, 2007

New Mercedes-Benz CL-Class in Depth

Interior: appointments for even the most discerning

Control system: fewer switches for more functions

Active Body Control: superb combination of dynamism and comfort

Intelligent Light System: five lighting functions to match driving and weather conditions

PRE-SAFE®: automatic partial braking before an impending accident

Driver-support systems: radar sensors make parking child’s play

Engines: eight and twelve-cylinder powerplants with noticeably more power

Tradition: seven generations of the Mercedes-Benz Coupé

* Selection

Wings: expressive anatomy

Flanks: intriguing lines

C-pillar: living tradition

Rear end: a beautiful back

Interior: welcome to the club

Materials: only the very finest

Control system: intuitive interface

Automatic partial braking when a collision is imminent

Radar sensors in the bumper and behind the radiator grille

Accident severity reduced by 40 percent

Flashing brake lights: effective warning when danger threatens

Night view assist: even better visibility at night

Up to 125 percent increase in safety

Important contribution to safer driving in the dark

Intelligent Light System: latest lighting technology as standard

Headlamp automatically pivots outwards

Passive safety: to the highest Mercedes standards

Robust floor structure with eight longitudinal members

Side structure of higher-strength steel

Rear-end structure designed to withstand extreme impact loads

Restraint systems: activation according to accident severity

Belt tensioner and belt force limiter for every seat

Mercedes safety even after an accident

High-tech adhesive in addition to welded connections

Easily repaired modules at the front and rear ends

Hybrid construction of two lightweight materials for the doors

Long-term protection: fully galvanised bodyshell and paint with nano-particles

In keeping with all Mercedes passenger cars, the new CL-Class is also protected by the 30-year MobiloLife warranty.

Aerodynamics: exemplary wind resistance and wind noise

Comfort as an audible experience

Noise analyses with a three-metre parabolic mirror

Background noise subjectively perceived as pleasant

Windscreen wipers: aero-technology with two motors

Windows: silver foil as an infrared reflector

*Electronically limited

Mercedes-Benz CL 500

Engine

Power transfer

Chassis

Dimensions and weights

Engine

Power transfer

Chassis

Dimensions and weights

Performance and fuel consumption

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