GENEVA MOTOR SHOW: Makeover for Mercedes C-Class

Bad news, BMW and Audi. Mercedes-Benz's mid-size premium juggernaut just got better.

The C-Class has shown its rivals a clean pair of heels, running out of showrooms so fast it's a regular in the top 10 model sales lists around the world, including claiming fourth position on the UK charts at least twice last year.

Benz sold an astonishing 415,000 C-Class sedans, wagons and coupes last year, built at its main Bremen plant in Germany, as well as East London in South Africa, Tuscaloosa in the US and Beijing, which also makes the long-wheelbase C-Class for China, the car's biggest market.

You might not know it's new to look at it, because the metalwork and the overall design theme are scarcely changed.

You have to look mighty hard inside, too, because Benz hasn't fitted it with the double-width digital infotainment unit it debuted in the S-Class and which has now migrated down into the new A-Class.

You wouldn't know it from the powerplants, either, because Benz is being decidedly cagey about how the 2018 Mercedes-Benz C-Class will move, how fast it will move and how much energy it will use doing it.

It's far from certain, though, that Benz will slot its new mild hybrid-equipped inline six-cylinder petrol engines into the C-Class, which would leave the C-Class continuing to fight with a range of inline four and V6 engines.

Daimler blames Germany's transport authority, the KBA, for being too slow to certify the updated C-Class and insists it can't publish official power, torque, performance, consumption and emissions data until it receives KBA approval.

The KBA insists it's not going slowly, but following its normal course of validating manufacturer claims against its test results for the new WLPT real-world tests.

Either way, there's an unseemly kerfuffle over what ought to be a fairly straightforward procedure of homologating the facelift of an existing model.

Not only will Benz not confirm what powerplants the C-Class will be using, it won't even confirm the transmission, though its in-house nine-speed automatic will be used throughout the range.

Sources at Daimler have insisted, though, that the car will move to three versions of the OM645 four-cylinder turbo-diesel engine to power the C 200d, the C 220d and the new C 300d.

The entry-level diesel will receive a 10kW boost over the old 2.2-litre motor to 110kW, the mid-level car will rise by 18kW to 143kW and the 300d climbs 30kW higher than the old 250d to hit 180kW of power.

There is no confirmation from Benz's official sources, but unofficial internal documents reveal that it will have just two initial petrol-powered models, both using the M264 four-cylinder turbocharged engine.

It will use 48-volt electrical systems to give the C 200 EQ-Boost mild-hybrid capability for added low-speed urge and better economy, though the more expensive C 300, bewilderingly, goes without the system (which usually adds about $US950 to a car's production cost).

The C 300 receives a 10kW boost to 190kW, though the mild-hybrid C 200 will deliver 140kW of power to rise by just 5kW over the outgoing car under normal circumstances. When the integrated starter-generator kicks in, though, it jumps to a 13kW advantage over the current car.

The C 200 will add the EQ-Boost tag to link it to its upcoming all-electric EQ brand, to which Benz will add two plug-in hybrid C-Classes, neither of which will be available from the start of production.

A step up from the current plug-in hybrid C-Class, the system benefits from the research and development of the stand-alone EQ brand's team and will be paired with both petrol and diesel power.

The modular plug-in hybrid system will mate up with the 2.0-litre petrol four to create the C 300e and the C 300de, both of which will deliver 50 per cent more electrical power than the C 300h thanks to a 90kW electric motor. That motor will mate to a 155kW version of the 2.0-litre petrol motor and a 142kW version of the diesel engine.

It also uses a far bigger lithium-ion battery, jumping up from 64kWh to 13.8kWh as Benz belatedly recognises China's demand for at least 50km of pure electrically driven range.

Instead of tangible areas like engines and gearboxes, Mercedes-Benz's official information focuses on the C-Class's optional headlights and a new AMG-Line model, with its diamond-pattern radiator grille.

The AMG-Line will also receive tweaks to the front and rear bumpers plus its "tailpipe trim varies according to the engine variant". Whatever that might possibly be.

The base-level headlight remains a halogen system with an LED daytime running light, then it can be stepped up to a full LED then a multibeam LED, with each headlight containing 84 separate LEDs that can illuminate individually.

The top-spec light incorporates an adaptive high-beam assistant system that allows the driver to keep using high-beam even around other cars, by simply blacking out or dimming an area around the oncoming car.

Above 40km/h, the car switches automatically to Ultra Range, which delivers what Benz claims is the maximum light intensity allowed by law, which still delivers 1 lux even 650 metres ahead of the car. It will then automatically mask out a u-shaped area around any oncoming car, allowing high-beam to continue lighting up the surrounding area.

That all feeds in to Benz's advanced safety features, which let the car see better even without the fancy (and doubtless expensive) headlights.

Its updated radar and camera systems allow it to see up to 500 metres ahead of the car at all times, delivering data to the computer that governs all of its safety and driver-assistance systems.

The new radar scans up to 250 metres in front of the car, 80 metres behind it and 40 metres to each side, while the analogue camera is responsible for reaching out to 500 metres. It also delivers a 3D picture to the computer covering up to 90 metres in front of the car.

Its optional Driver Assistance package delivers active cruise control that is paired up with the car's navigation data, just like in the E-Class and S-Class sedans, so it can pre-empt when it needs to speed up or slow down for corners or roundabouts.

While the entry-level models retain the two-tube instrument cluster, the higher-spec models use a fully digital version, complete with three different layouts (Classic, Sport and Progressive).

Even the analogue dials flank a 5.5-inch digital screen for detailed information, and Benz calls it the 'Classic' dash.

The fully digital screen is a 12.3-inch unit, boasting 1920x720 pixel resolution, which can be ordered to display navigation data for the first time (though Audi's been doing it for years).

Both the 7.0-inch and optional 10.25-inch infotainment screens sit high on the dashboard, with the bigger screen offering its three display styles of its own.

It has the Blackberry-style touch pads on the steering wheel to navigate around the car's options, plus a scroller mounted on the centre console to move around the infotainment screen.

The navigation system features car-to-X networking for traffic alerts, petrol station data and even parking availability

Besides engine data, Benz has also studiously avoided the trend towards touchs-creens, though, which leaves the scroller, the touchpads and voice control as its only options.

There are also two USB ports, Bluetooth, Apple CarPlay and Android Auto, while Qi-standard smartphones and devices can be charged wirelessly.