Mercedes-Benz M-Class - 2012

Lily

B.R
Staff member

















(from Mercedes-Benz Press Release) The new Mercedes-Benz M-Class: Champion of refined efficiency


Stuttgart. The third generation of the Mercedes-Benz M-Class sets a new benchmark in the SUV world. Its low fuel consumption and emission figures are especially impressive. Across the range, fuel consumption is an average of 25 percent lower than for the previous model. Particularly noteworthy in this respect is the ML 250 BlueTEC 4MATIC, which has an NEDC consumption of just 6.0 l/100 km (158 g CO2/km) and can travel up to 1500 kilometres on a single tank of fuel. Yet for all this efficiency, the M-Class retains its fascination, in the way it uniquely combines agility with driving enjoyment and superior comfort. Further impressive features of the ML include 4MATIC permanent all-wheel drive, new developments to the chassis and innovative driving dynamics systems, all of which improve performance in both on-road and off-road situations. Its active and passive safety features are typical for the brand. A characteristic body design, together with a versatile interior that is highly conducive to its occupants' wellbeing, enhance the driving experience in the new M-Class.

Dr Thomas Weber, Member of the Board of Management of Daimler AG for Group Research and Mercedes-Benz Cars development, commented: "The M-Class embodies all the automotive experience that we have accumulated over 125 years and thus represents – in short – a quantum leap in terms of efficiency, safety, agility, driving enjoyment and design!"

Long-distance runner: high efficiency ensures extensive range

State-of-the-art engines, a clear policy of engine downsizing, a best-in-class Cd value of 0.32 and a comprehensive range of BlueEFFICIENCY measures all contribute to delivering superb energy efficiency. BlueTEC diesel engines and the new generation of BlueDIRECT petrol engines provide the basis for the excellent economic efficiency and outstanding environmental performance of the new M-Class. As far as the diesel models are concerned, now only available as BlueTEC units with SCR emissions technology, the focus is firmly on downsizing and on the new version of the V6 CDI engine.
In the ML 250 BlueTEC, 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 uses a completely reworked 3.0-litre V6 engine, which also more than meets the EU6 emissions standard and delivers far better performance, yet with considerably reduced fuel consumption. The efficiency improvements have been achieved, above all, through the use of the innovative TWAS (twin-wire-arc spraying) technology already used with great success since 2005 in AMG's high-performance engines. The positive results here have led Mercedes-Benz to adapt this cylinder wall coating technology for use in the V6 diesel engine as well. The process reduces internal friction in the engine significantly. At the same time, the weight has been reduced by 4.3 kg, as there is no longer any need for the grey cast iron cylinder liners that, until now, had to be pressed into the engine block. The benefits are striking: with these measures alone, fuel consumption could be reduced by around 3 percent.

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 engineering. In addition to the ECO start/stop function that comes as standard, these measures include the new seven-speed 7G-TRONIC PLUS automatic transmission with a new fuel-economy converter, friction-optimised bearings and a transmission oil thermal management system. Low-friction axle drives, electric steering and tyres with low rolling resistance also play their part in reducing fuel consumption.

The optimised belt drive system with decoupler, together with 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. 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 (Selective Catalytic Reduction) emission control technology.

An intelligent use of lightweight construction techniques has enabled the development engineers to stop the steadily increasing weight spiral. The control arms of the front and rear axles, for example, as also 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.

Detailed analysis: the "energy-transparent vehicle" makes things clear

The development tool "energy-transparent vehicle", created in-house by Mercedes-Benz, was used for the first time as part of the M-Class development process. The pioneering opportunities presented by this method, which detects the possibilities for optimisation right down to 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 wheel bearings.

Air flow optimisation: the most aerodynamically efficient SUV in its class

With a drag coefficient, or Cd value, of 0.32, the new M-Class (ML 250 BlueTEC) also sets a new best figure for this vehicle class (total aerodynamic drag Cd x A = 0.92 m2; predecessor 0.94 m2). Intensive 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 body shell, 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

The result: excellent comfort and driving dynamics

A high level of comfort, dynamic on-road handling and excellent off-road capability are part of even the standard equipment package on the new M-Class. For the first time, the steel suspension of the M-Class chassis now includes selective damping. During normal driving on only moderately uneven roads or during slow off-road driving, the system responds with a soft ride that enhances the occupants' wellbeing as well as the car's off-road capability. In order to maintain this sense of wellbeing during hard driving or abrupt evasive manoeuvres, the shock absorbers work even harder in such circumstances, so ensuring a high level of driving stability. The M-Class driver is supported here by an electric steering system that provides the optimum level of steering power assistance to suit the particular driving situation. Parking or manoeuvring off-road is made so much easier, thanks to the availability of maximum power 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. At higher speeds, the power assistance is reduced, to the benefit of the car's handling.

For those who want to venture off surfaced roads, the ML 350 BlueTEC 4MATIC and ML 350 4MATIC BlueEFFICIENCY models feature a comprehensive off-road programme as part of their standard equipment. This considerably improves the options once the going gets tough. It includes the permanent all-wheel drive system 4MATIC and the electronic traction control system ETS, as well as an off-road button that activates a special off-road transmission mode.

• To improve traction, the slip thresholds and shift points of the 7G-TRONIC PLUS system have been raised
• A flatter accelerator pedal curve improves the sensitivity with which the driver can accelerate
• Off-road ABS ensures optimum braking on a loose surface

Start-off Assist and the HOLD function are further features helping the driver to pull away on a slope. Downhill Speed Regulation, or DSR, enables the M-Class to maintain automatically the speed set via the cruise control lever.

For those wishing to drive the M-Class more extensively away from surfaced roads, we recommend the optional ON&OFFROAD package.

Full programme: ON&OFFROAD package for all eventualities

The ON&OFFROAD package for the new M-Class uses a range of six transmission modes to optimise driving dynamics and handling safety, by ensuring that the necessary drive control is there to cope with the very different operating conditions encountered on and off-road. One automatic mode, two specifically off-road modes and three on-road modes are available.
The system is controlled via a rotary actuator on the centre console. The settings for AIRMATIC, and the drive line, are adapted to accommodate these specific requirements. The six transmission modes in detail:

Automatic – covers most everyday driving operations
Offroad 1 – light terrain, dirt roads and tracks
Offroad 2 – challenging off-road terrain with hilly stretches
Winter – for driving in wintry conditions on slippery roads, on snow, ice or with snow chains
Sport – more adventurous, dynamic driving on winding roads
Trailer – optimises moving off, manoeuvring and braking with a trailer

Despite so many options, for the driver the decision is always very clear: the setting is made intuitively, and the programme selected is shown in the multifunction display as well as in very realistic, almost photo-quality imagery on the screen of the COMAND system. Irrespective of which underlying programme is set, the gear reduction, lock, DSR or the self-levelling suspension of the AIRMATIC system can all be adjusted individually. As with the basic settings of the ON&OFFROAD package, it is practically impossible for the driver to make mistakes. Illogical settings, which might have a negative impact on handling, safety or traction, are ruled out. If there is any doubt, the system will revert to automatic mode.

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