2012 Mercedes-Benz M-Class

The evolution of the dashboard in Mercedes-Benz off-road vehicles, from the early days of the G-Class through to today’s new M-Class, makes it clear how much aspects of comfort and wellbeing have now come to the fore:

• In the G model dating from 1979, square-edged shapes defined the flat dashboard. The angular instrument panel was laid on top of this, while the dashboard console, also angular in shape, and the glove compartment area were hung beneath. As if pieced together from modular sections, the individual elements reflected the clear look of a commercial vehicle. Their simple practicality dispensed with any embellishments, instead giving off an air of rustic charm with a rather metallic-like effect. At the time, this was totally appropriate for an off‑road vehicle.
• The dashboard in the first generation M-Class dating from 1998 was also primarily functional in nature, and made only tentative concessions to a design based around comfort. Nevertheless, the first hints of the more comfortable and friendlier interior design to be found in saloons were noticeable. Curves and sweeping lines helped to avoid an impression of austerity. Trim elements were not often incorporated into the sober visual design, however, and functionality continued to dominate.
• The design of the instrument panel in the new Mercedes-Benz M-Class is completely on a par with its counterparts found in luxury-class saloons: modern, friendly, equipped with high-quality materials and stylishly designed. At the same time, matching details reflect the superior character of a premium SUV.

SUV environment with the comfort of a luxury saloon

The modern Mercedes-Benz definition of the appropriate interior of an SUV becomes evident as soon as the pleasantly high seating position is accessed via the wide-opening doors. The spacious, bright interior provides noticeably more elbow room than its predecessor (34 mm more in the front, 25 mm more in the rear) and thus an enhanced sense of space and comfort. The driver takes to the wheel behind a 4-spoke multifunction steering wheel with twelve trapezoidal control buttons for trip computer, radio, telephone, etc. – which is also of a high saloon standard. The 7G-TRONIC PLUS automatic transmission is controlled via the DIRECT SELECT DIRECT SELECT lever as well as DIRECT SELECT shift paddles on the steering wheel.

The broad instrument panel stretches out behind the steering wheel. With its clear emphasis on width, it continues the horizontal lines from the exterior design in the interior. Exciting areas and powerful lines highlight the vehicle’s sporty aspirations.

An eye-catching feature of the instrument panel is a large decorative trim element that is then continued along the doors in a very harmonious wrap-around effect. These generously proportioned trim elements, in a three-dimensional design, are available in four high-quality wood finishes, or in aluminium. The interior of the new Mercedes-Benz M-Class can thus be appointed to reflect either exclusive refinement or sporty sophistication, according to the customer’s taste. The door openers and seat adjustment switches have been inset with precision craftsmanship into the side trim elements. The door centre panels feature distinctive decorative stitching, with a separate, exclusive look for the Sports package.

All clear: instruments and COMAND screen

The state-of-the-art instrument cluster with its two clear and extremely legible round dials and a large, 11.4 cm monochrome display between them, impresses with the high quality of its design. Dominating the centre of the instrument panel in the centre of the vehicle is the large colour screen for the infotainment system. There is a choice between CD radio, CD radio with integrated navigation system or the COMAND control and display system with the latest navigation system (14.7 cm screen diagonal for the CD radios, 17.8 cm for the internet-enabled COMAND Online). The control and display concept was developed specifically with user-friendly operation in mind. Infotainment, navigation and communication systems are intuitive and easy to operate using the metal Controller located on the centre console. Two buttons are used to switch the display on and off.

Vertical rectangular air intake vents either side of the large screen serve to emphasise the more functional aspects of the SUV. The outer air vents are the same shape but in this case horizontally positioned, thus giving an added design flair. The dashboard console and air intake vents feature edging with a quality Silver Shadow finish. The row of high-gloss silver switches in the dashboard console are characterised by their ergonomic design and discernible precision. The same applies to the air conditioning and ventilation setting, as already proven in Mercedes-Benz saloons.

The centre console incorporates an integrated arm and handrest, in front of which is located the Controller and various switches, such as those for the off-road programmes and AIRMATIC air suspension. All controls feature a quality, uniform look. They create a harmonious effect and the lend the interior a touch of class in the many places in which they are used.

Numerous stowage facilities, high degree of variability and temperature-controlled cup holder

Numerous, easily accessible stowage facilities in the M-Class can accommodate bottles, mugs, keys, coins and much more. Each of the four doors can also easily accommodate a large 1-litre bottle.

A light touch of the handrest in the centre console opens up a large stowage compartment which houses a 12V socket as well as easily accessible connections for mobile audio devices. To make long journeys and extensive off‑road excursions more enjoyable, the centre console also features two innovative cup holders which can keep drinks either cool or warm at temperatures of between 8°C and 55°C.

High-quality materials and strong colour values

The seats in the new Mercedes-Benz M-Class are designed to provide a high level of comfort on long journeys as well as excellent lateral support. All important parameters can be electrically adjusted, including height, backrest angle, seat cushion angle and reach. Generous seat adjustment travel of more than 350 millimetres lengthways and more than 90 millimetres in height ensure that drivers of all sizes will always find the ideal seating position.

A high level of variability characterises the rear seats, which are fitted with an armrest and cup holder. The angle of their backrests can be adjusted, and they can be also folded in the ratio 1/3:2/3, thus creating a through-loading feature for long objects, such as skis, without having to sacrifice all of the rear seat positions. Folding both backrests as well as the seat cushions forward creates a level load compartment with a capacity of 2010 litres up to the roof liner.

Exclusively available for the new M-Class are three seat and two sports seat variants in six different colour combinations. The sports seats reserved for the Sports package feature a different stitching pattern which is also incorporated into the door centre panels.

Four colours are available for the interior appointments: black, almond beige, alpaca grey and marron/tobacco brown. These can be combined with a wide range of materials: fabric/ARTICO man-made leather in black, ARTICO man-made leather and leather in six colour combinations, in conjunction with the Interior Sports package with DINAMICA microfibre and leather in black.

Chassis in detail: Dynamism meets comfort

All models in the new M-Class range offer excellent comfort and superb driving dynamics as standard – both on the road and away from the tarmac. Besides the steel suspension with selective damping, there are also some new chassis developments and innovative dynamic handling control systems available, which are designed to make driving the new premium SUV an even more effortlessly superior experience. These include the AIRMATIC air suspension with Adaptive Damping System (ADS), the ACTIVE CURVE SYSTEM for active roll stabilisation and the ON&OFFROAD package with six driving modes. A comprehensive package of measures has also been included to ensure that the M-Class is at the forefront of its segment for acoustic and vibration comfort too. To ensure that the driving experience continues to be a complete pleasure after hundreds of thousands of kilometres, the development engineers punish both chassis and body in practical trials staged worldwide and in series of selective laboratory tests. Some of the toughest examinations here include the body testing facility and the road-simulation test rig.

A high level of comfort, dynamic on-road handling and excellent off-road capability are ingrained into the new Mercedes-Benz M-Class as standard. The chassis of the steel-sprung M-Class now includes selective damping for the first time, meaning the shock absorbers’ compensatory forces are of a flexible nature, rather than having a rigid setting. During normal driving on moderately uneven roads or off-road excursions at low speeds, the system is tuned for a gentler ride to the benefit of the occupants’ sense of wellbeing and the vehicle’s off-road abilities. In order to keep the occupants feeling at their ease when driving at a brisker pace or performing abrupt evasive manoeuvres, the dampers switch to a firmer setting in such circumstances for a high level of handling stability. The M-Class driver is helped here by an electric steering system that provides the optimum level of power assistance to suit the particular driving situation. The system therefore makes light work of parking or off-road manoeuvres by maximising steering assistance. The SUV also scores here with the tightest turning circle in its market segment. The 180‑degree turn is negotiated within a circle diameter of just 11.8 metres. As the speed increases, however, assistance is reduced in favour of greater directional stability.

For those who want to venture off surfaced roads, the ML 350 BlueTEC 4MATIC and ML 350 BlueEFFICIENCY 4MATIC models feature an extensive off-road specification as standard, which considerably enhances their capabilities when the going gets tough. Apart from 4MATIC permanent all-wheel drive and the electronic traction control system 4ETS, this also includes an off-road button that activates a special off-road driving mode:

• To improve traction, the wheel slip thresholds and the shift points of the 7G-TRONIC PLUS transmission are raised
• A flatter accelerator response curve enables more sensitive throttle control
• Off-road ABS ensures optimum braking characteristics, especially on loose surfaces

Start-off Assist and the HOLD function furthermore come to the driver’s assistance when performing a hill start, while Downhill Speed Regulation, or DSR, enables the M-Class to automatically maintain the speed set with the cruise control lever on descents.

For anyone wishing to go exploring off the beaten track even more in the new M-Class, there is the optional ON&OFFROAD package.

Comfort system: AIRMATIC air suspension with ADS

The AIRMATIC full air suspension system including the Adaptive Damping System ADS offers a soft basic suspension setup with a low natural frequency, where full spring travel is available even when the vehicle is fully laden. This provides the basis for excellent ride comfort on road combined with noticeably superior handling stability. AIRMATIC compensates for variations in vehicle load and driving state, at the same time as acting as a level control system. Away from the tarmac, the air suspension increases the vehicle’s off-road prowess by offering additional ride heights. The body can be raised or lowered with the engine running at any time, either automatically or at the driver’s request with a simple turn of the rotary control in the centre console. The system is speed sensitive, meaning that it lowers the body at higher speeds to minimise aerodynamic drag while increasing handling stability too. The air suspension system’s basic components include:

• Air-filled spring struts on the front axle with integral ADS dampers
• Air springs with separate ADS dampers on the rear axle
• Electric compressor with central pressure reservoir and pressure sensor
• Air spring valves
• Electronic control unit
• Sensors for level control and damping control

The adaptive damping system ADS II is a fully automatic, electronically controlled system, which adapts the damping force at each wheel to suit changing requirements using a skyhook algorithm. In contrast to a passive system with a constant damper setting, the vehicle’s motion is controlled uniformly in all driving situations, leading to improved handling stability and a considerable reduction in body movement. The skyhook algorithm regulates the damping forces at each wheel so as to lessen the forces exerted on the body by the movement of the wheels. When there are low levels of body excitation, the Mercedes-Benz M-Class drives with damping level 1 active. Should the body speed exceed a certain threshold, however, the system will switch to the skyhook algorithm and constantly alternate between the second and third damping levels by means of fast-acting solenoid valves in order to counter the body’s rolling and pitching movements. Under even more dynamic handling conditions, level 4 is engaged, and when driving in Sport mode, level 4 damping is activated at all times. Damping control at each individual wheel takes place extremely fast – depending on the control command, the valves are capable of setting one of the characteristic curves described here in less than 0.05 seconds:

• Level 1 Soft rebound / soft compression for comfortable ride characteristics, gentle body movements and little longitudinal and lateral acceleration
• Level 2 Soft rebound / firm compression (skyhook mode)
• Level 3 Firm rebound / soft compression (skyhook mode)
• Level 4 Firm rebound / firm compression: for minimising wheel load fluctuations when cornering and braking, high longitudinal and lateral acceleration for enhanced handling safety

The current driving state is determined using a steering angle sensor, 4 turning angle sensors und the road speed as derived from the ESP®signal and the brake pedal switch. Based on these signals, the control unit calculates the current damping forces required and actuates the appropriate damper characteristic curves. The driver is able to choose between Sport and Comfort modes manually by pressing a switch.

New dynamic handling control system: cornering without rolling

Active roll stabilisation in the form of the ACTIVE CURVE SYSTEM can be optionally combined with both the AIRMATIC air suspension with Adaptive Damping System (ADS) and the ON&OFFROAD package. This system uses active anti-roll bars on the front and rear axles, which it controls automatically as a function of the lateral acceleration, road speed and the ADS Comfort/Sport switch setting. The ACTIVE CURVE SYSTEM compensates for the roll angle of the body through bends, greatly increasing agility and driving pleasure in the process. The system has the additional effect of increasing handing stability and therefore safety, particularly at higher speeds. Further benefits of the ACTIVE CURVE SYSTEM include even greater ride comfort both when cornering and driving in a straight line, together with enhanced off-road abilities. The various control strategies in detail:

• Comfort is improved when driving straight ahead as the rotary actuators decouple the two halves of the front and rear anti-roll bars in this situation, meaning that the anti-roll bars are “open” and do not react to a stimulus on just one side, such as bumps or potholes.
• Increased ride comfort and more dynamic handling when cornering, because the system actively influences the anti-roll bars’ torsional moments and twisting angles. The anti-roll bars’ torsional moment furthermore remains constant in response to a stimulus on one side, such as is the case when driving over a pothole on the outside of the bend. Thanks to the individual control at the front and rear axles, distribution of the roll momentum can be varied, allowing the self-steering properties to be actively adapted to the prevailing driving situation. The handling characteristics are adjusted for extra agility when driving along country roads and for even greater stability on the motorway.
• When driving in extreme off-road conditions at low speeds, the two anti-roll bars at the front and rear axles are decoupled. This leaves the anti-roll bars “open”, allowing greater axle articulation.

The key componentry of the ACTIVE CURVE SYSTEM comprises a belt-driven hydraulic pump and an oil reservoir in the engine compartment, as well as a valve block and active anti-roll bars at both the front and rear axles. In contrast to a passive anti-roll bar, the active variant is split into two in the middle, and the two halves are connected with one another by means of hydraulic rotary actuators. Using the CAN signals relayed to it by pressure sensors and a lateral acceleration sensor, the electronic control unit regulates the hydraulic pressure.

The complex workings of the ACTIVE CURVE SYSTEM

The hydraulic pump feeds oil to the system from the oil reservoir. The pressure control valves and directional control valves integrated into the valve blocks at the front and rear axles set the desired pressure and twist the active anti-roll bars in the appropriate direction for the driving situation. Inside the hydraulic rotary actuators that are built into the active anti-roll bars there are six oil-filled chambers, three of which are pressurised for each direction of travel, i.e. a left or right-hand bend. The front valve block additionally assumes the task of distributing the oil flow between the two axles, irrespective of load.

Full programme: ON&OFFROAD package for all eventualities

The ON&OFFROAD package for the new M-Class uses six different driving modes to optimise driving dynamics and handling safety by providing the optimum drive control needed to cope with the wide spectrum of operating conditions encountered both on and off the road. The added benefit compared to the Off-Road Pro Engineering package offered previously is plain to see: whereas before there was one optimum driving mode for the road and one for off-road, drivers now have the choice of an automatic mode, as well as two specially programmed off-road and three on-road modes.

The specific driving modes for all-wheel drive resolve a conflict of objectives that has previously hampered further development of 4MATIC and the 4ETS electronic traction system as well as ESP® and ASR. To take an example: on off-road tracks, it is important that the control systems respond very gently due to the low friction coefficients, but this makes a sporty setup virtually impossible. Conversely, a sporty basic setup impairs performance abilities in off-road terrain. In the past, the engineers always succeeded in finding excellent compromises which worked brilliantly under all conditions and continue to do so. The new ON&OFFROAD package with its specific driving modes, however, enables driving dynamics and handling safety to be optimised almost as far as is physically possible under all operating conditions by maximising networking between the individual control systems.

The system is operated using a rotary control on the centre console, which adapts the AIRMATIC settings and the drivetrain to suit the specific requirements. The six driving modes in detail:

• Automatic – covers the wide operating spectrum of everyday driving
• Offroad 1 – light terrain, tracks, driving over fields
• Offroad 2 – challenging off-road terrain with climbs
• Winter – for driving in wintry conditions on roads affected by freezing rain, snow or ice, or with snow chains
• Sport – for serious driving along winding roads
• Trailer – optimises start-off, manoeuvring and braking characteristics when towing a trailer

Despite so many options, the driver is never in any doubt about mode selection: the setting is made intuitively, while the driving mode selected is visualised in the multifunction display as well as in virtually photo-realistic quality on the screen of the COMAND system. If the driver selects the Winter mode, for instance, the display shows the M-Class in snow. The Sport setting displays a racetrack with red-and-white curbs, while images of off-road terrain with different profiles appear for Offroad 1 and 2. The display is interactive too: steering input and spring travel correspond to the actual values, while the graphics include additional information on the steering, gradient and tilt angles, the AIRMATIC level, the pre-selected speed for Downhill Speed Regulation (DSR), as well as the selected drivetrain settings including reduction gear and differential lock.

Irrespective of which basic mode is set, the reduction gear, differential lock, DSR and the AIRMATIC system’s level control can all be adjusted individually. As with the basic settings for the ON&OFFROAD package, it is not possible for the driver to make mistakes here either. Illogical settings, which would have a negative impact on handling stability, safety or traction, are precluded. If case of doubt, the system will revert to automatic mode.

In terms of “hardware”, the ON&OFFROAD package comprises an underguard, a two-stage transfer case with reduction gear, an inter-axle differential lock and enhanced AIRMATIC functionality that allows a maximum ground clearance of 285 millimetres and a fording depth of 600 millimetres.

Haven of calm: optimum vibration and acoustic comfort

The new M-Class promises relaxed and therefore safe motoring under all possible (and even impossible) conditions. By paying close attention to detail every step of the way, the development engineers in the Mercedes Technology Centre have significantly improved what they call the NVH comfort level (Noise, Vibration, Harshness). This is a decisive parameter for the general sense of wellbeing on board, whilst also contributing to driver-fitness safety, especially on long journeys.

The basis for the high level of NVH comfort is provided by the very rigid SUV bodyshell of the Mercedes-Benz M-Class. The development engineers were faced with some particular challenges here. For example, they had to make allowance for the optional panoramic glass sunroof’s large aperture in the construction. The objectives set for drive comfort were no less ambitious. Substantial improvements have been achieved in this regard compared to its predecessor, thanks to features such as map-controlled, hydraulic engine bearings, a resized aluminium transmission cross member with integral vibration damper, as well as the overhauled 7G-TRONIC PLUS with twin-turbine damper and centrifugal pendulum. Potential noise penetration from the engine compartment through to the interior is minimised by a major assembly partition wall made from plastic and the intelligent use of soundproofing to suit requirements. Aero-acoustic enhancements include the vehicle glazing with its high-insulation acoustic windscreen, additional sealing in the side sections, plus the streamlined add-on parts such as the restyled exterior mirror housings.

The measures at a glance:

• Improved rigidity of the front end structure thanks to struts between the upper and lower levels of side members
• Hybrid construction of front module increases comfort at the same time as reducing weight
• Cockpit cross member made from particularly rigid magnesium alloy
• Intelligent use of soundproofing to suit requirements: In the production facilities, insulation is applied to the bodyshell very precisely by computer-controlled robots. Insulation with varying mass distribution in parts is used in the firewall area in accordance with the potential noise penetration.
• Aluminium transmission cross member with integrated vibration damper on the diesel models
• Vibration-optimised 7G-TRONIC PLUS with twin-turbine damper, plus, on the diesel models, centrifugal pendulum
• Map-controlled engine bearings on the diesel models
• Decoupled exhaust system on the diesel models
• Standard chassis with selective damping, as an option: AIRMATIC air suspension with Adaptive Damping System or AIRMATIC air suspension with Adaptive Damping System and ACTIVE CURVE SYSTEM dynamic roll stabilisation
• Electric steering
• Major assembly partition wall made from plastic in order to minimise penetration of noise from engine compartment into the interior
• External noise minimised by acoustic encapsulation of engines
• High-insulation acoustic windscreen
• Additional aero-acoustic sealing in the side sections

Body testing facility: the M-Class on the road simulator

A totally dependable body and chassis systems that can cope with high levels of strain under even the most demanding conditions over hundreds of thousands of kilometres are particularly indispensable in an SUV such as the Mercedes-Benz M-Class, with its broad on-road and off-road performance spectrum. Besides practical tests with the prototypes, the engineers also subject the M-Class body to an exhaustive test of durability during the development phase that ranks amongst the toughest examinations in the world for body and chassis. Lasting several weeks, the load cycle covers a total of 3000 kilometres, which corresponds to an average of 300,000 kilometres of routine driving. This is because every kilometre driven on one of the state-of-the-art test rigs is 100 times more gruelling than in everyday driving. SUVs which come through this endurance test unscathed will be able to withstand the strain of a tough day’s driving on and off the road in the Mercedes-Benz M-Class.

The test programme comprises various “load spectra”, which the engineers refer to as virtual test tracks. The individual courses are not dreamt up by the team of testers, however. Instead, real routes were digitised, including the “Heide” test with its tortuous pothole and cobblestone sections, special off-road torsion drives with maximum torsion levels, and corrugated tracks in Africa with high-frequency excitation. Computers orchestrate the sophisticated test rigs on the basis of this data. The rigs’ servo-hydraulic cylinders mercilessly knock, jerk, shake and twist the bodies, just like on a real test drive. In all, 26 actuating cylinders arranged vertically and horizontally are responsible for stimulating the body on the test rig. A hydraulic system generates a pressure of 210 bar and pumps as much as 2000 litres of oil into the cylinders every minute. This enables the formidable forces of up to 20,000 Newtons to be produced, which shake the car thoroughly in quick succession at the computer’s command.

To allow them to detect any damage early, the Mercedes engineers halt the test rigs after around 100 kilometres each time, or when one of the 150 or so sensors that permanently monitor the vehicle emits a signal to automatically shut down the facility. The body is then inspected meticulously for the tiniest sign of damage. The experts are highly experienced, so they know exactly where the critical points are and what they should look out for. Apart from the weld points and bonded connections, the panels along the force transmission paths between the chassis and body are also carefully scrutinised, as these areas have to withstand very high forces in an SUV when negotiating rough roads or torsion sections. The candidate is deemed to have passed the endurance test if its body shows zero signs of damage. Even the finest of cracks, which can only be spotted with the aid of special fluorescent colours and under ultraviolet light, are unacceptable.

Road-simulation test rig: an ordeal for the chassis

The road-simulation test rigs are just as punishing as the body testing facility. Applying identical load spectra over the same distance, the test engineers torture the M-Class chassis in all of its different variants here – from the basic steel suspension with selective damping to the AIRMATIC ADS air suspension to the version with the new ACTIVE CURVE SYSTEM. In contrast to the body testing facility, only the chassis is installed on the test rig here. The pivot points are fixed to the solid test rig frame, while the wheel hubs are connected to the servo-hydraulic cylinders using special mounting fixtures. This test setup allows the complete chassis to be examined in isolation, producing even more exact findings.

Compared to the testing for road-going saloons, the programme for a Mercedes-Benz SUV is far more rigorous. As with the body testing facility, the chassis is also subjected to all manner of different on-road and off-road load cycles. In contrast to real-life driving with prototypes, which continues to take place too, the constant laboratory conditions on the road-simulation test rig allow the engineers to analyse individual chassis parameters more effectively, and thereby take targeted action to correct any vulnerabilities found during development. The several weeks of laboratory testing staged over a distance of 3000 kilometres would take about half a year if carried out under real-life conditions.

Engines and transmissions in detail: The SUV efficiency champion

The third-generation M-Class sets a new benchmark in the SUV segment. The low fuel consumption figures and exemplary emissions figures are particularly impressive. Compared with the outgoing model, the entire model range consumes 25 percent less fuel on average. This kind of formidable reduction in fuel consumption is unprecedented with any Mercedes-Benz SUV model changeover to date. An ultra-modern engine line-up, concerted engine downsizing, the best-in-class Cd value of 0.32, extensive BlueEFFICIENCY measures and new development tools such as the “energy-transparent vehicle” all play their part in delivering the good energy efficiency figures. The highlight comes in the guise of the ML 250 BlueTEC 4MATIC, which is 28 percent more economical than its predecessor, boasts NEDC fuel consumption of 6.0 l/100 km (158 g CO2/km) and has a range of up to 1500 kilometres on a single tank – figures that only a few years ago remained the preserve of the compact class.

BlueTEC diesel units and the new generation of BlueDIRECT direct-injection petrol engines form the basis for the excellent economy and outstanding life cycle assessment of the new M-Class. In this respect, downsizing takes centre stage as far as the diesel models are concerned:

• In the ML 250 BlueTEC 4MATIC, the 3.0-litre V6 of the previous model is replaced by the thrifty four-cylinder EU6-standard unit already familiar from, for instance, the S-Class.
• The ML 350 BlueTEC 4MATIC features an extensively revamped 3.0-litre V6, which also betters the EU6 standard and offers far better performance coupled with a substantial reduction in fuel consumption. Thanks to state-of-the-art AdBlue® emission control technology both diesel models comfortably meet the EU6 standard slated for introduction in 2014.

State-of-the-art engine technology from the inventor of the diesel passenger car

The 2.2-litre CDI engine turns the ML 250 BlueTEC 4MATIC into the most economical SUV in its class. With NEDC fuel consumption of 6.0 l/100 km, the model even outperforms any hybrid model currently offered by the competition. Despite the low fuel consumption figures, this Mercedes-Benz M-Class model boasts maximum torque of 500 Nm at 1600 rpm and rated output of 150 kW (204 hp) with outstanding performance: the M-Class accelerates from 0 to 100 km/h in 9.0 seconds before going on to a top speed of 210 km/h.

Two-stage turbocharging produces high torque even at low engine speeds. The compressor package – already fitted in the compact SUV GLK 250 CDI 4MATIC – made up of a small high pressure (HP) and a large low pressure (LP) turbocharger contributes decisively to the high output on a par with the 6 cylinder unit in the predecessor model ML 300 CDI BlueEFFICIENCY 4MATIC. The two turbochargers are connected in series, and each has a turbine and a compressor driven by this turbine. The HP turbine is located directly at the exhaust manifold and initially allows exhaust gas to flow through it; it then rotates at up to 215,000 revolutions per minute. The HP turbine housing features an integral bypass duct, which can be opened or closed by means of a charge-pressure control flap. If the flap is closed, the whole exhaust stream flows through the HP turbine, so that the exhaust-gas energy is available solely for the HP turbine drive. This means that the optimum charge pressure can be built up at low engine revs.

The two compressors are likewise connected in series, and are in addition connected to a bypass duct. The combustion air from the air filter first flows through the low-pressure compressor, where it is compressed as a function of the LP turbine’s output. This pre-compressed air then passes into the high-pressure compressor, which is coupled to the HP turbine, where it undergoes further compression. The result is a genuine two-stage turbocharging process. The major advantage of this sophisticated, demand-related control of the combustion air supply using two turbochargers is improved cylinder charging, and therefore high torque even at low engine speeds. Fuel consumption is also reduced. When the car is driven, this concept makes itself felt by harmonious driving characteristics with no turbo-lag, a favourable torque curve across the entire engine speed range, instant responsiveness and excellent performance.

The V6 diesel engine in the ML 350 BlueTEC 4MATIC guarantees effortlessly superior traction. It develops 190 kW (258 hp) and impressive torque of 620 Nm. Despite its extraordinary performance this version boasts combined NEDC fuel consumption of 6.8 litres of diesel per 100 kilometres. The highly efficient V6 diesel unit delivers effortlessly superior performance: the ML 350 BlueTEC 4MATIC accelerates from standstill to 100 km/h in 7.4 seconds before moving on to a top speed of 224 km/h. While delivering performance on a par with the predecessor model, the ML 450 CDI 4MATIC with V8 diesel engine, the new unit, however, boasts 36 percent lower fuel consumption.

Just like the ML 250 BlueTEC 4MATIC, the ML 350 BlueTEC 4MATIC also ranks among the world’s cleanest diesel models: BlueTEC is a technology developed by Mercedes-Benz to reduce emissions from diesel vehicles, especially nitrogen oxides. AdBlue®, an aqueous urea solution is injected into the exhaust gas stream as part of this process, releasing ammonia, which reduces up to 80 percent of the nitrogen oxides into harmless nitrogen and water in the downstream SCR (Selective Catalytic Reduction) catalytic converter. Upshot: both models already comply with the EU6 exhaust emissions standard due to be implemented in 2014. The AdBlue® tank is located under the luggage compartment floor to protect it in the event of a crash, has a capacity of 25.7 litres and is topped up every 25,000 kilometres at the regular service intervals. The filler opening is located behind the side fuel filler flap alongside the tank filler neck and is marked clearly with a luminous blue cap. This configuration allows the ML driver to top up the tank easily if they take full advantage of the off-road capabilities of the M-Class and are unable to find a service station off the beaten track. AdBlue® is available as a refill container from any Mercedes-Benz dealership; the instrument cluster provides a timely indication of the need to top up the tank.

Latest-generation BlueDIRECT direct-injection engine for the ML 350 4MATIC BlueEFFICIENCY

The ML 350 4MATIC BlueEFFICIENCY petrol-engined model features the groundbreaking technology of the new generation of V engines from Mercedes-Benz. At the heart of the BlueDIRECT technology package lies the enhanced third-generation spray-guided direct petrol engine with piezo-electric injectors. In combination with multi-spark ignition, this technology offers further possibilities for fuel savings.

The V6 engine in the ML 350 4MATIC BlueEFFICIENCY utilises a new stratified combustion process with a considerably extended characteristic map and fuel-efficient lean-burn technology (“homogeneous stratified mode”). As the name implies, HOS is a combination of homogeneous lean-burn and classic stratified combustion. The first injection is sprayed into the intake stroke, forming a homogeneous basic mixture. Actual “stratified” injection takes place during the compression stroke before ignition, and is a single or double injection depending on the characteristic map.

The third-generation direct-injection system also features rapid multi-spark ignition (MSI). How it works: following the first spark discharge and a brief combustion period, the coil is rapidly recharged and a further spark is discharged. The MSI system enables up to four sparks to be discharged in rapid succession within one millisecond, creating a plasma with a larger spatial expansion than conventional ignition. Controlling this rapid multi-spark ignition enables both the time lapse before the next spark and the combustion duration for the relevant operating point to be optimally adjusted. This provides scope for optimising the centre of combustion and improving residual gas compatibility, especially during stratified charge operation.

The ultra-modern 3.5-litre V6 unit has been designed as a naturally aspirated engine. As a major distinction from the preceding engine in the ML 350 4MATIC, the V-angle between the cylinder banks has been reduced from 90 degrees to 60 degrees. This has enabled the balancer shaft compensating primary vibrations to be omitted. As a result the driver notices an outstanding level of comfort. The design highlights of the 3.5-litre V6 include a completely new air intake and exhaust system in conjunction with a variable resonance intake manifold and optimised inflow and outflow. Result: with the same displacement, the output compared with the previous 200 kW (272 hp) model is increased by 12.5 percent to 225 kW (306 hp), while maximum torque has increased by 5.7 percent to 370 Nm (predecessor: 350 Nm) and now is available over a broader engine speed range from 3500 to 5250 rpm. In parallel with this substantial increase in power, Mercedes engineers have achieved an equally impressive reduction in fuel consumption. The predecessor’s NEDC fuel consumption has been reduced by 25 percent. The new V6 petrol engine in the ML 350 4MATIC BlueEFFICIENCY consumes 8.5 litres per 100 kilometres, making it the most economical petrol model in its class. The model combines excellent consumption figures with dynamic performance, accelerating from standstill to 100 km/h in 7.6 seconds, and with a top speed of 240 km/h.

New dimensions in energy efficiency

The performance of the Mercedes-Benz M-Class engines becomes particularly apparent when looking at the reduced energy requirements coupled with a marked increase in power output per litre for the three M-Class generations since 1997. Comparison of the weight-specific consumption figures (l/100 km per 100 kg) reveals the tremendous development potential of the conventional internal combustion engine:

Long-distance champion: a high level of efficiency ensures a long range

The range for a full tank of fuel on the new M-Class is particularly impressive. This parameter is very important for a vehicle that knows virtually no bounds. Here, the ML 250 BlueTEC 4MATIC – the most economical SUV in its class by far – stands out. With NEDC consumption of 6.0 l/100 km, the frugal diesel engine with the standard 70-litre tank can cover around 1170 kilometres before needing to stop for fuel. If the vehicle is fitted with the optional 93-litre tank, the car can even cover up to 1500 kilometres between refuelling stops.

Attention to detail: a fine finish adds efficiency

The excellent fuel economy is underpinned by a comprehensive package of BlueEFFICIENCY measures as well as by this state-of-the-art engine technology. In addition to the ECO start/stop function that comes as standard, these measures include the new seven-speed 7G-TRONIC PLUS automatic transmission. Low-friction axle drives, electric steering and tyres with low rolling resistance also play their part in reducing fuel consumption.

The re-engineered 7G-TRONIC PLUS, standard on all Mercedes-Benz M-Class models, boasts an integrated ECO start/stop function, even lower converter slip and optimised efficiency. A central role is played by the new torsion damper, which eliminates torsional eccentricities and vibrations in the transmission even more effectively. The lower the rpm and the lower the number of cylinders, the more severe these can be. This results in a conflict of aims between comfort and fuel-efficient operation. Mercedes-Benz developers resolved this by using a so-called twin-turbine damper, which is also fitted with a centrifugal pendulum on the diesel models. Depending on the rpm, this moves the centre of mass and allows comfortable operation even in the most economical operating range. Furthermore, the optimised damping allows a marked reduction in the slip of the torque converter lockup clutch even under low loads, which also contributes to fuel savings. In addition, the optimised damping of rotational irregularities and vibrations in the transmission allows an even faster response to driver commands via the accelerator pedal. Friction-optimised bearings and new transmission oil thermal management also help reduce fuel consumption.

The optimised belt drive system with decoupler, together with intelligent, on-demand control of all ancillary components and pumps, also helps to reduce the energy requirements of the new M-Class. The oil and water pumps in the engine, as well as the fuel pump in the rear section of the vehicle, are only activated according to actual need. The same control logic is used in the THERMATIC and THERMOTRONIC air conditioning systems. In these, the coolant compressor only runs when necessary. An internal heat exchanger and the sophisticated sensor system including a demisting sensor on the front windscreen ensure optimum efficiency of the air conditioning systems in the interior. A key factor in the diesel engines is also the optimisation that has been undertaken of the flow and counterpressure in the exhaust system with its SCR emission control technology.

A consistent use of lightweight construction techniques has enabled the development engineers to keep the weight of the new M-Class on a par with that of its predecessor, despite more equipment. The links on the front and rear axles, for example, along with the bonnet and wings, are made out of light and yet very strong aluminium alloys, while the cross member for the instrument panel is made of magnesium.

Optimised aerodynamics: the most aerodynamic SUV in its class

With a drag coefficient, or Cd value, of 0.32, the new Mercedes-Benz M-Class (ML 250 BlueTEC) also sets a new best figure for this vehicle class (total aerodynamic drag Cd x A = 0.92, predecessor 0.94). Painstaking simulations undertaken with the digital prototype, along with final touches added in the wind tunnel, ensure a perfect flow of air around the vehicle. The key factor determining the low wind resistance is the aerodynamic efficiency of the basic bodyshell, including the optimised design of the front bumper with its integrated spoiler, of the A‑pillars and of the roof spoiler, plus numerous other detailed improvements.

These include:

• Sealing around the radiator section with adjustable fan shutter
• Sealed joints between the bonnet and the headlamps
• Front wheel spoilers
• Air outlets in the front wheel well liners
• Redesigned exterior mirror housings
• Optimised roof spoiler
• Side spoilers on the rear window (ML 250 BlueTEC 4MATIC)
• Underfloor and engine compartment panelling
• Aerodynamically optimised light-alloy wheels for the diesel models

Detailed analysis: “energy-transparent vehicle” creates transparency

The “energy-transparent vehicle” development tool, created in-house by Mercedes-Benz, was piloted as part of the M-Class development process. The outstanding opportunities presented by this method, which can detect the possibilities for optimisation in even the most minute component, will be exploited on all new model series in the future. An exact and meticulous examination of the flow of energy throughout the vehicle (tank to wheel) helps the development engineers to optimise every single assembly that has an impact on fuel consumption, right down to individual components, such as wheel bearings.

The idea for the “energy-transparent vehicle” stemmed from the failure in the past to verify or demonstrate clearly the many factors affecting consumption and the interaction between fuel-saving measures. Using the “energy-transparent vehicle” tool, the engineers can now detect detailed potential optimisation measures by breaking down energy flows into cause and effect and analysing energy interactions within the entire vehicle.

The process draws on complex, highly precise metrology which records some 300 energy-relevant measurement points with a sampling rate of up to 1000 measured values per second. Every minute some 2.4 million measured values are generated, which can subsequently be analysed to reliably pinpoint optimisation potential. The process is complemented by energy simulation models which are validated by means of the measured variables. This enables the energy efficiency of individual major assemblies and components as well as the entire vehicle to be analysed and quantified.

Once the specialists have identified a vehicle component with energy shortcomings, they team up with the relevant specialist departments to devise solutions. This cooperation focuses on design, or the properties of the materials used in individual vehicle components such as wheel or axle bearings. In addition, modified control strategies can also produce the desired outcome.

The “energy-transparent vehicle” process which is exclusive to Daimler enables the development engineers to highlight and leverage optimisation potential both for cars with conventional internal combustion engines as well as hybrid, electric or fuel-cell drives. In future, this process may even give rise to a generally applicable development tool for all machines and help boost energy efficiency across the board. A wide range of applications are conceivable. Whether in industry for power stations, (wind) generators, pumps or conveyor systems, in the home for refrigerators, washing machines, dryers and lawnmowers, or for transportation applications involving ships, trains or planes – the optimisation potential of disparate technologies to save energy could be analysed in detail with the consistent usage of this technique and implementation recommendations made.

Safety in detail: Just one star is enough

In line with the Mercedes-Benz brand philosophy, the new M-Class represents the embodiment of the Mercedes-Benz holistic safety concept of REAL LIFE SAFETY, which is derived primarily from what happens in a real accident situation. The extremely robust occupant compartment of the Mercedes-Benz M-Class, together with the front and rear deformation zones, forms an effective basis for the occupant protection system. Both active safety and driver-fitness safety in the new M-Class are further improved by Assistance Systems, already primarily familiar from the S and E-Class.

As with all passenger car models from Mercedes-Benz, the philosophy behind the safety concept of the M-Class is broken down into four phases:

• Safe driving: avoiding danger, warning and assisting the driver in good time
• In the event of danger: anticipating and enabling preventive protective measures
• In an accident: providing protection as needed
• After an accident: avoiding even worse consequences and making rapid assistance possible

The very high level of safety already achieved in the previous model has been increased even further thanks to meticulous attention to detail during the development stage. The many “invisible” Mercedes-Benz solutions in particular bring measurable benefits in real accident situations. To support new technologies or the evolution of existing systems, the engineers carried out numerous crash tests which went way beyond the tests normally specified, such as the roof-drop test for example, as well as various rollover tests. When it detects the need to do so, a rollover sensor system can activate side and window airbags, as well as belt tensioners. In total, as part of the M-Class development Mercedes-Benz tested 36 totally different loads under real test conditions. This included comprehensive simulations for the digital prototype. Following this intensive development programme, the M-Class now has the potential to pass all international ratings with the best possible results.

The Mercedes-Benz M-Class is also able to demonstrate the highest possible protection potential when it comes to more vulnerable road users such as pedestrians or cyclists. In addition to yielding areas in the front section, folding exterior mirrors and smooth contours, the risk of injury caused by the vehicle has been reduced by adjusting the bonnet and increasing the distance to the components in the engine compartment. In addition, for the first time in the SUV segment, an active bonnet is fitted as standard equipment. It is able to reduce the acceleration forces of an impacting pedestrian or cyclist by intercepting them earlier.

“Electronic crumple zone”: even more safety in the M-Class

As ever, the best accident is one which does not happen at all. The safety engineers at the Mercedes Technology Center are working intensively on this rather simple sounding statement, which in practice is actually a lot more difficult to implement. Both active safety and driver-fitness safety in the new M-Class are further improved by the numerous active and passive assistance systems:

• ATTENTION ASSIST, warns the driver of drowsiness
• Speed Limit Assist, displays road signs in the instrument cluster
• Tyre pressure loss warning system
• Intelligent Light System with specific lighting functions to match the relevant road and weather conditions
• Night View Assist Plus with automatic person recognition
• ADAPTIVE BRAKE with the functions Hill-Start Assist, priming, brake drying and hold function
• Brake Assist BAS to support the driver in critical braking manoeuvres
• DISTRONIC PLUS with BAS PLUS
• Lane Keeping Assist warns the driver as soon as it detects that the driver has unintentionally left a recognised marked lane. In addition, Active Lane Keeping Assist can react with lane-correcting brake application
• Blind Spot Assist warns the driver when vehicles are detected in the area of poor visibility, the so-called “blind spot”. Additionally, Active Blind Spot Assist can counteract a possible collision by specific application of the brakes on one side of the vehicle, if the driver does not react to the warning.
• Park Assist with PARKTRONIC, a system which can detect parking spaces and carry out the steering manoeuvres required for the parking process, simply leaving the driver to operate the brake and accelerator
• Reversing camera, e.g. with “back-in” mode with dynamic guide lines for reversing into narrow parking bays or to aid with the coupling of trailers
• Adaptive brake light warns vehicles behind in an emergency braking situation with flashing brake lights

Standard equipment forming part of the safety concept of the new M-Class includes the anticipatory safety system PRE-SAFE®, which combines active and passive safety synergies to reduce the loads exerted on the vehicle occupants in the event of an accident by up to 40 percent. Depending on the potential accident situation detected, the following reversible measures can be initiated for preventive occupant protection:

• Driver and front passenger seat belts are tensioned
• Windows are closed
• Sliding sunroof is closed
• Front passenger seat is adjusted (when fitted with Memory package)

Body: high energy absorption in the event of a front impact

The extremely robust occupant compartment of the Mercedes-Benz M-Class, together with the front and rear deformation zones, forms an effective basis for the occupant protection system. The focus of the work here has been the tangible reduction of the loads exerted on the occupants. In the case of front impacts, the engineers were able to achieve more uniform deceleration, and therefore a lower peak load on the occupants. This was made possible by means of:

• Design of the front axle carrier as a crash element, which is able todeform in a specific manner and in the case of an offset crash, for example, can divert the energy to the side of the vehicle opposite the side of impact
• A novel aluminium gearbox crossmember mount with offset function: isolated against noise and vibration during normal operation, in the event of a crash this component is activated via hooks so that the centre tunnel can absorb additional energy in this area (diesel versions only)
• Guide ramp on the brake booster, thus preventing unwanted block formation between the brake booster and the damper dome. The brake booster is also rotated to minimise possible brake pedal intrusion
• A crash joint ensures that the mudguard is pushed away at the driver’s door, and prevents the door from jamming after the impact. For the most part the doors can be opened without much effort
• Ultra-high-strength steels in the A-pillar enhance the stability of the passenger compartment in both front impacts as well as in different rollover scenarios, primarily enabling doors to be opened easily after an offset crash
• Projected sills create a direct load path to the front wheel. As a result, any possible forcing or intrusion of the wheels into the footwell can be avoided
• Optimum energy conversion in the event of a front crash despite relatively short front-end length, thanks to enabling the load paths from the crashbox to the longitudinal body member, from the wheel to the sill, and due to the deformable subframe, which guides forces into the centre tunnel via the engine/transmission joint
• The energy-absorbing steering column deforms up to 100 millimetres when subjected to external forces, thus freeing up additional deformation space for energy conversion. As a result, the loads on the driver can be reduced in the area of the head, neck and thorax

Side-impact protection thanks to intelligent bodyshell

Similar to the design of the front area of the new M-Class, the vehicle’s intelligent bodyshell design also performs impressively in side-impact accident scenarios. The specific distribution of high rigidity and high deformability helps to ensure that the occupants benefit from favourable kinematics in the event of a side impact:

• The lower part of the B-pillar, an important component in side impacts, is highly compressible, whereas its upper part is extremely rigid. As a result, intrusions and the speed of intrusions in the lower area are reduced, while in the upper area high-strength steels on the exterior sides of the pillar prevent it from buckling unfavourably in a side impact. In addition, this design solution increases the stability of the passenger compartment in the event of a rollover
• The stiffening of the floor structure by means of a supporting element made of an ultra-high-strength material running across the entire width of the vehicle, and ultra-high-strength reinforcements in the driver’s seat crossmember, help to reduce deformations, primarily in the event of a pole impact. As a result, the occupant survival space benefits from even better protection, and the thorax load on the occupants is reduced
• The geometry and body connections of the pillars and the roof frame made of ultra-high-strength material have been optimised to provide the best possible crash safety

Brilliant finish: the rear assembly of the M-Class

The rear area too of the M-Class also protects the sturdy passenger compartment in crash situations thanks to specific deformation work, therefore minimising the loads on the occupants. A special impact test conducted to check tank leakage gives an indication of the exceptional load capabilities of the rear part of the Mercedes-Benz M-Class body. The test involved running a crash carriage into the rear of the M-Class at 80 km/h. The tank system survived this fatal impact without suffering any leaks.

To enhance rigidity, increase the energy absorbtion capability and improve deformation behaviour, the multi-piece rear longitudinal members feature a continuous closed cross-section with stepped plate thicknesses (tailored blanks). The spare wheel well forms an integrated part of the steel floor, and a steel flexible bumper bracket carries the rear bumper covering and is connected to the rear structure via two steel crashboxes.

Comprehensive restraint systems for even better occupant protection

The passive occupant protection systems, together with the “electronic crumple zone” and intelligent body design which have already been described, provide optimum protection potential, placing the M-Class at the top of its market segment. As part of this, a number of new deployment strategies are used. For example, the system can detect an impending rollover in the event of crash and if necessary deploy the head, side and window airbags, as well as the seat belt tensioners. Thanks to the new generously-sized side airbags and the window airbags with extended area of coverage, in the event of a crash the occupants can be more uniformly supported from the shoulder area down to the pelvic area, and thereby better protected. In side impacts too, the danger of injury is reduced thanks to extended coverage.

Additional protection potential is also provided for rear seat passengers with seat belt tensioners and force limiters on the outer seat positions. The integration of optional thorax bags in the tilt-adjustable folding seat backrests enables optimum airbag positioning for each backrest position. The components of the passive occupant protection systems include:

• Two-stage adaptive airbags for the driver and front passenger
• Kneebag for the driver
• Sidebags for driver and front passenger (combined thorax/pelvis bags)
• Sidebags in the rear row of seats as an option
• Windowbags across both rows of seats from the A to the C-pillar
• 3-point seat belts on all five seats
• Pyrotechnic reel tensioners and permanent belt force limiters as well as electrically reversible belt tensioners in the front, reel tensioners and single-stage force limiters for the outer seats in the rear
• ISOFIX child seat anchorage
• Belt height adjustment for the driver and front passenger
• Belt status display for rear-seat passengers in the instrument cluster Automatic child seat recognition (optional) with deactivation of the front passenger airbag if a special Mercedes-Benz child seat is used in a rear-end collision, a passive head restraint system developed specifically for this purpose can reduce the forces exerted on occupants

The M-Class also protects its occupants after a crash

As part of the POST-SAFE® functions, the new M-Class can activate a variety of systems which can contribute towards avoiding post-accident risks. After a more serious crash, the hazard warning lights are automatically activated to warn surrounding traffic. At the same time, the doors are automatically unlocked so that the emergency services have the best possible unrestricted access to the passengers. And thanks to partial opening of the side windows, the interior is better ventilated after deployment of the restraint systems.

On detecting a collision, the central control unit switches off the fuel system to reduce the risk of a possible fire. After determining the cylinder positions, the engine management system opens the injection valves of those cylinders which are not under compression and discharges the high-pressure fuel area by direct evacuation of the remaining fuel in the combustion chamber. This reduces the risk of fuel escaping. To avoid fuel losses, all Mercedes-Benz M-Class models are also fitted with cut-resistant fuel lines in all relevant locations. This also helps to reduce the risk of a possible fire breaking out.

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