Mercedes-Benz CLS: New four-cylinder diesel engine gives the ultimate in driving efficiency







Published by Gerald Ferreira Date: September 7, 2012
Categories: Mercedes-Benz, Mercedes-Benz CLS-Class

New four-cylinder diesel engine gives the ultimate in driving efficiency

  • Diesel engine: four-cylinder CDI available for the first time in the luxury coupé segment
  • Refined: ECO start/stop function for reduced consumption in urban traffic

Mercedes-Benz CLS 350

Efficiency at the highest level: this is the common characteristic shared by all engines used in the Mercedes-Benz CLS. All of the engines feature increased performance and torque compared with previous models, while at the same time boasting significantly reduced consumption and CO2 emission levels.

Setting entirely new standards for efficiency in the luxury segment is the CLS 250 CDI BlueEFFICIENCY. Available for the first time in the four-door Coupé segment, the four-cylinder direct injection diesel engine has already enthralled customers of the E-Class, C-Class and M-Class models. With an output of 150 kW, a top speed of 242 km/h and a full 500 Nm of torque, it provides complete driving pleasure, yet will astound you when filling up with its consumption figures comparable to those of a compact car: on average the CLS 250 CDI BlueEFFICIENCY uses between 5.1 – 5.3 litres per 100 km, which is equal to CO2 emissions of 134 g/km

In addition to optimisations in the powertrain the CLS 250 CDI BlueEFFICIENCY is fitted with the enhanced 7G-TRONIC PLUS automatic transmission as standard and the sophisticated ECO start/stop system helps to ensure extreme efficiency even when driving in urban traffic.

“As the appeal increases for coupé based diesel cars, we feel the time is right in bringing our diesel variant of our 4-cylinder four-door coupé,” says Selvin Govender, Divisional Manager, Mercedes-Benz Cars.

“The CLS 250 CDI BlueEFFICIENCY delivers on all the finer elements you would expect from a Mercedes-Benz CLS-Class, from futuristic design, to superlative quality of comfort features.  The CLS 250 CDI BlueEFFICIENCY gives our customers the opportunity of owning a CLS with an ECO friendly engine at an attractive price proposition,” adds Govender.

The new diesel engine of the new CLS at a glance

Model CLS 250 CDI BlueEFFICIENCY
Cylinder arrangement / number   4/in-line
Displacement [cc] 2143
Rated output [kW] at [r/min] 150 / 4200
Rated torque [Nm] at [r/min] 500 / 1600 - 1800
Fuel consumption combined [l/100 km] 5.1 – 5.3
CO2 emissions combined [g/km] 134

ECO start/stop function: significantly reduced consumption in urban traffic

When the car is at a standstill, the engine does not need to be running and therefore does not need to consume fuel. Recognition of this essentially simple fact is behind the ECO start/stop function is the 7G-TRONIC PLUS automatic transmission. In order to implement the auto start and auto stop function with a very high level of comfort in a Mercedes-Benz, it has been necessary to develop complex control logistics and a series of new or modified components, such as a Hall sensor for the crankshaft and a high-output starter motor.

7G-TRONIC PLUS automatic transmission available for the first time with the four-cylinder diesel

The CLS 250 CDI BlueEFFICIENCY model comes with the 7G-TRONIC PLUS automatic transmission as standard, for which the torque converter and main transmission have been developed and improved further with regard to fuel consumption and comfort. The new generation of the torque converter provides an improved dynamic response, better durability and reduced noise and vibration levels thanks to a new hydraulic circuit, as well as enhanced dampers and torque converter housing. The extreme wheel-slip reduction of the torque converter housing, combined with larger mechanical damper de-coupling, helps to reduce consumption significantly. In addition, the gearshift program in ECO mode has been changed in favour of lower engine r/min at cruising speeds.

With friction-optimised bearings and gaskets, as well as a new automatic transmission oil (FE-ATF) with reduced viscosity combined with an enhanced additive package, the transmission itself also contributes towards reducing consumption. When the cooling limits are observed, the increased service life of the new oil results in new oil change intervals of every 125,000 kilometres. The improved electrohydraulic assembly of the transmission and the new friction-reducing materials used on certain transmission parts, combined with optimised software, also lead to better shift quality.

The exterior: classic Coupé styling with distinctive front

As with other models in the CLS range, the CLS 250 CDI BlueEFFICIENCY continues its pioneering role as a trendsetter. What immediately strikes the eye is the innovative front design. Visually, the radiator grille is not integrated into the bonnet but is formed separately. This highlights the long, sporty bonnet even further. The grille is dominated by the large central star, which underlines the car's relationship to the other coupés of the brand and strengthens the brand identity.

The typical CLS outline, with its elegantly long proportions, is the dominating attribute of the new model. The effect of the dynamic, athletic form has been enhanced with a new interplay of lines and areas. The front edge of the structure above the wings slopes off towards the rear. This novel design feature, called the dropping line by designers, represents a new interpretation of a formal design element harking back to the uniquely rich wealth of forms present in historic Mercedes-Benz sports cars.

A distinctive and muscular sports car-like shoulder line above the rear axle highlights the athletic character of the new CLS. A total of 11 different paint finishes can be combined with the four interior colours - black, alpaca grey, almond beige and black/aubergine.

The interior: design brings quality to life

The interior of the CLS 250 CDI BlueEFFICIENCY is also distinguished by a timeless design which combines straightforward elegance with innovative details and handcrafted perfection. An eye-catching feature is the wrap-around effect of the cockpit: a high line sweeps from the driver's door over the instrument panel support and across to the front passenger door. The central display has also been integrated harmoniously into the upper part of the instrument panel. At the same time, the downward sweeping side line on the doors continues the dynamic dropping line of the exterior.

As a design trendsetter, the CLS 250 CDI BlueEFFICIENCY offers a wide variety of individualisation options. Four interior colours and four trim designs in high quality leather are available.The CLS also exudes refined sportiness with its lavish and high-class trim elements which can be found on the instrument panel support, the centre console and parts of the door trim. Customers can choose between two exclusive wood types: high-gloss brown burr walnut and high-gloss black ash at no additional charge.

COMAND APS multimedia system

Nowadays, nobody wants to miss out on the news, the telephone, route guidance or music listening pleasure when in the car. For this reason Mercedes-Benz has equipped the new CLS with state-of-the-art infotainment facilities, which stand out for their high performance capability, but above all for ease of use.

The COMAND APS multimedia system, developed by Mercedes-Benz, includes a DVD player for audio and video as well as a navigation system whose data is stored on a 40-gigabyte hard drive, allowing extremely fast access to the navigation data and, compared to DVD-based navigation, even faster route calculations. The high-resolution map appears on the 17.7 cm colour display in the centre of the instrument panel and excels in providing useful additional information. By way of example, the map shows the outlines of prominent buildings along the route to aid orientation.

Mercedes-Benz combines COMAND APS with the voice-operated control system LINGUATRONIC and a so-called text-to-speech function as standard. This makes it possible for SMS messages, address book entries or radio station names to be read out to the driver. The system automatically reads out new traffic reports that are relevant to the current route.

Features include speed-sensitive volume control, a keypad for entering telephone numbers and radio frequencies, a colour display in the centre of the dashboard, and a Bluetooth interface to connect a mobile phone to the hands-free system wirelessly. Eight loud-speakers supplied as standard and located in the doors ensure excellent sound quality.

Optional features include the Logic7 surround sound system developed by Mercedes-Benz together with the audio specialists Harman/Kardon® delivers an outstanding performance with three-dimensional sound as a natural 360-degree musical experience for all passengers.iPods, USB sticks or other external audio devices can link to the infotainment system of the CLS 250 CDI BlueEFFICIENCY through a media interface in the stowage compartment in the centre console.

Less drag and substantially quieter

Aerodynamics are a key contributory factor to the outstanding efficiency of the CLS range. Although the latest model is wider than its predecessor and thus offers the wind a larger frontal area, drag has been reduced by up to ten percent. As a result of fine-tuning measures on the body and the application of technical measures such as a cooling air louver and aerodynamically optimised wheels, the Cd value – which defines the drag coefficient – has been reduced by 13%, to 0.26. Other focuses of aerodynamic development have been on reducing wind noise and keeping all surfaces which contribute to visibility free of soiling – a key element of perceptual safety.

Specifically, the key focuses of aerodynamic development work were as follows:

  • Exterior mirrors, optimised in terms of aerodynamics, aeroacoustics and dirt deflection, positioned expediently on the beltline
  • Aerodynamically efficient design of the front and rear aprons and the boot lid
  • Improved sealing of the radiator section and utilisation of air flows to make efficient use of the available cooling air, deployment of a cooling air louver
  • Flow-optimised drip rails in the area of the A-pillars
  • Optimum coordination between the taper of the C-pillars and the shaping of the vehicle's rear end
  • Aerodynamically optimised underbody with wheel spoilers and extensive engine compartment and main floor panelling
  • Aerodynamically optimised wheels; Aero Wheel used for the first time on the CLS 250 CDI BlueEFFICIENCY
  • When the CLS is fitted with AIRMATIC air suspension, the body is lowered by 15 millimetres at speeds of over 140 km/h

Wind noise: a highly refined driving experience even at high speeds

In order to improve comfort and in the interests of a more refined driving experience at high speeds in particular, the aerodynamics and body experts have tweaked a number of details to attain a further reduction in the noise level in comparison to the predecessor model.

The following measures result in reduced wind noise:

  • Optimised sealing of joints between bonnet and radiator grille
  • Positioning of the exterior mirror on the beltline, optimised joint sealing between head and base of mirror
  • Elaborately designed wind deflector for the tilting/sliding sunroof
  • Sophisticated system of seals between the frameless doors and the body; improved sealing of door handles; increased rigidity of the doors themselves
  • Damping package at many points of the body to reduce low-frequency noise

Protection from soiling: further improvement in vision and visibility

The areas of the side and rear windows of relevance to safety remain free of soiling when driving in rain at between 80 and 160 km/h, thanks to effective channelling and drainage of the incoming water. A water runnel with continuously diminishing height and an optimised roof trim strip channel water which lands on the front windscreen along the roof. The mirror positioned on the beltline additionally helps to keep the side window free of soiling more effectively than a traditional bridge mirror.

The water flowing over the roof is diverted away from the rear window by means of a co-ordinated water management system comprising channels to the left and right of the rear window through which the water flows down.

Value proposition

Countless optional extras make it possible to individualise one's CLS further - including opting for active multicontour seats, heated front seats, LED High Performance headlamps, Keyless Go and the Harman/Kardon sound system.  Many optional support systems in the Driving Assist package include DISTRONIC PLUS, new Active Blind Spot Assist and Active Lane Keeping Assist with brake actuation.

Over and above this, Mercedes-Benz has put together the AMG Sports package offering exciting combinations of optional extras.

The AMG Sports package comprises a multifunction sports steering wheel in nappa leather in the 3-spoke design, with flattened bottom section, aluminium pedals, AMG bumpers to the front (with single-louvred grille) and rear, AMG alloy wheels in size 18 or 19, AMG floor mats, visible tailpipes, and in the interior, in combination with black leather seats, light-coloured felled seams on the seats, headrests and armrests. With the AMG Sports package, the automatic transmission has a third shift programme - M - which allows the gear to be selected manually using the paddles on the steering wheel. In addition to this, the adaptive suspension is more sportily tuned.

As with all Mercedes-Benz passenger cars, the CLS four-door coupé comes standard with the MobiloDrive 120 maintenance package of 6-years/120 000 km with and a 2-year /unlimited vehicle warranty as a standard feature.

“Due to low CO₂ emissions of 134 g/km, the CO₂ tax is extremely low for a vehicle in this segment, as is the exemplary fuel consumption of 5,1 litres per km,” concludes Govender.

  • CLS 250 CDI BlueEFFICIENCY R700 000
  • AMG Sports Package R28 700