First look: Four cylinders for new Mercedes M-class

MERCEDES-BENZ has revealed full details and no fewer than 50 official images of its larger yet sleeker third-generation M-class, which brings four-cylinder power for the first time, just days after first images were leaked on the internet.

There is no confirmation of the Australian line-up that will be released here in the second quarter of next year, but in Europe the new M-class range will open with a 2.1-litre turbo-diesel variant that is as fuel-efficient as a hybrid Toyota Camry.

The new ML250 BlueTec emits just 158 grams of CO2 per kilometre and sips as little as six litres of diesel every 100km – 28 per cent less than the ML300 CDI BlueEfficiency it replaces – giving it a driving range of 1170km, or 1500km with an optional 93-litre fuel tank.

Despite that, the 2143cc ML250 BlueTec delivers the same 150kW and 500Nm outputs as the outgoing 3.0-litre V6-powered ML300 CDI and accelerates to 100km/h in 9.0 seconds (up from 8.3 seconds) on its way to the same 210km/h top speed.

The frugal Euro 6 emissions-compliant four-pot oil-burner, which also powers models including Europe’s S-class, is one of two diesel engines for the redesigned M-class, which will be launched in Europe and the US following its world debut at the Frankfurt motor show in September.

While a 4.6-litre turbocharged V8 will later replace the 5.5-litre V8 in the existing ML500, the two diesels and a more powerful yet more economical petrol V6 for the 2012 ML350 will make the new M-class range 25 per cent more efficient from launch.

The third-generation M-class, which shares chassis components with Jeep’s new Grand Cherokee because development began before Daimler’s split from Chrysler, will be topped by a replacement for the range-topping ML63 – powered by AMG’s new twin-turbo 5.5-litre V8 – and the petrol-electric V6 hybrid version not sold in Australia.

Key to the efficiency gains is the standard fitment across the range of an automatic idle-stop system, plus electric power steering, low-friction axle drives, low-resistance tyres, on-demand oil, water and fuel pump operation, intelligent air-conditioning compressor control and Selective Catalytic Reduction (SCR) emission control technology.

Also central is an upgraded seven-speed automatic transmission across the all-4Matic permanent four-wheel drive M-class range.

Dubbed ‘7G-Tronic Plus’, the new transmission comprises a new economy-biased torque converter including an optimised belt drive system with decoupler, friction-optimised bearings and a transmission oil thermal management system.

In addition, the new ML350 BlueTec’s “completely reworked” 3.0-litre V6 turbo-diesel employs the same twin-wire-arc-spraying (TWAS) cylinder wall coating technology seen in AMG V8s since 2005, reducing internal friction enough to negate the need for cast-iron cylinder liners, saving 4.3kg over the current ML350 BlueEfficiency engine.

The result is a Euro 6-compliant diesel V6 that displaces the same 2987cc but increases peak power from 170 to 190kW and torque from 540 to 620Nm – reducing 0-100km/h acceleration from 7.6 to 7.4 seconds and increasing top speed from 220 to 224km/h while slashing consumption from 8.9 to 6.8L/100km and CO2 emissions from 235 to 179g/km.

The 3.5-litre petrol V6-powered ML350 BlueEfficiency, meantime, gains third-generation direct-injection technology dubbed ‘BlueDirect’ and comprising new piezo injectors with injection pressure of 200 bar, multi-spark ignition and a new stratified spray-guided combustion process.

ML350 outputs rise from 200 to 225kW and from 350 to 370Nm – slashing the 0-100km/h sprint claim from 8.4 to 7.6 seconds and lifting top speed from 225 to 235km/h - while fuel consumption falls from 11.4 to 8.5L/100km and CO2 emissions drop from 266 to 199g/km.

Also aiding the new ML’s efficiency is an aerodynamic drag coefficient of just 0.32Cd in ML250 BlueTec guise, which Mercedes claims makes it the slipperiest SUV in its class.

Apart from its sleeker overall body design, contributing factors to the improved aero performance include an optimised rear roof spoiler and front bumper with integrated spoiler, smoother A-pillars, sealing around the radiator section and adjustable fan shutter, sealed joints between the bonnet and the headlights, front wheel spoilers, air outlets in the front wheel-well liners, redesigned wing mirrors, underfloor panelling, aerodynamic wheel designs and, for the ML250, rear-window side spoilers.

Other technical advances include the fitment of variable damping for the first time with steel springs and an electric steering system that is claimed to offer a best-in-class turning circle of 11.8 metres.

An off-road package will again be available - this time with six driving modes for the upgraded 7G-Tronic auto – and comprises a two-speed transfer case, longitudinal differential lock, underbody guard and enhanced Airmatic air suspension functionality to raise ground clearance to 285mm and fording depth to 600mm.

The new M-class will come standard with adaptive front airbags, a driver’s knee airbag, side curtain/window airbags and front side thorax/pelvis airbags, but rear side airbags will be optional.

There are also a pedestrian-friendlier Active Bonnet and seatbelt reminders for all five seats.

Naturally, it will also feature most of Mercedes’ latest driver-assist technologies from the E and S-class, including Attention Assist drowsiness detection, Pre-Safe collision preparation, adaptive brake lights, a reversing camera and tyre pressure monitors.

Optional safety features will include Intelligent Light System, Night View Assist Plus with automatic person recognition, Speed Limit Assist, Lane Keeping Assist, Blind Spot Assist, Distronic Plus with BAS Plus, Pre-Safe Brake and Active Park Assist.

Mercedes did not reveal precise exterior dimensions but claims the interior delivers 35mm more front and 25mm more rear elbow room.

The front seats now offer 350mm of longitudinal adjustment and 90mm of seat height adjustment, while the rear seats now have an adjustable backrest.

Folding both backrests and seat cushions forward is said to create a flat cargo compartment of up to 2010 litres, while a 114mm screen between the instrument dials will be accompanied by a standard 147mm central TFT colour screen for the twin-tuner MP3/WMA/AAC-compatible CD player with USB, Aux-in and Bluetooth connectivity – the latter for hands-free telephony and audio streaming.

An optional 178mm high-resolution TFT colour display will offer a six-DVD changer and, for the first time in the M-Class, internet access, while four interior colours will be available: black, almond beige, alpaca grey and tobacco brown/maroon (pictured).

In Europe, these will be combined with either Artico man-made leather, fabric/Artico or six leather colours, while an Interior Sports package will include Dinamica microfibre and black Artico.

Apart from narrower C-class-style headlights, a new-look lower front bumper, LED daytime running lights and smoother overall lines, the new M will feature new wheel designs ranging from 17 to 20 inches in diameter.

Mercedes’ original M-class went on sale in Australia in September 1998 and was replaced by the second-generation W164 model here in September 2005 – two years after BMW’s first X5 arrived here.

While the second-generation W164 brought a bigger and much sexier body with more power and better efficiency, a facelift in September 2008 comprised a new nose, new interior and upgraded infotainment systems.

M-class sales were down 20 per cent in May and remain five per cent down so far in 2011, accounting for 8.2 per cent of luxury SUV sales – less than Audi’s top-selling Q5 (11.4 per cent) and the X5 (10.2 per cent).