Mercedes-Benz F700

So, another big lumbering Mercedes saloon then? Not a bit of it. Although the F700 might be 5.17m long – somewhere between the S-class and long-wheelbase S-class – the F700 is supposedly cleaner and more frugal than any current S-class.

This is thanks to its innovative ‘Diesotto’ engine. The F700 also features a hybrid drive and suspension that reads the road ahead. And, for those who are familiar with the online world Second Life, there's an avatar too.

Diesotto? Sounds like a mix of diesel and the Otto cycle. That’s just what this engine is. The F700 has a 1.8-litre four-cylinder engine that is supposed to combine the low emissions of a petrol engine with the consumption of a diesel. With the Diesotto engine, this very large F700 manages 55.3mpg and emits just 127g/km of the dirty stuff.

But don't think this engine lacks power, as there are two sequential turbochargers, plus a hybrid system to assist when the car moves off. The hybrid system allows stop/start running. There's also direction injection, variable valve lift and a variable crank.
This crank allows for the especially clever bit: the ignition. Running on conventional petrol, the Diesotto engine operates with spark ignition under start-up and full loads, but under partial loads (low and medium speeds) it switches to diesel-style compression ignition. Mercedes calls this controlled auto ignition (CAI) and it means lower operating temperatures. This in turn means fewer nitrogen oxide emissions, while a three-way catalytic converter mops up the rest.

The Diesotto engine makes 235bhp and 295lb ft, and the electric motor adds another 20bhp. This means a 0-62mph time of 7.5 seconds, and the aforementioned impressive consumption and emission figures. And not only is the engine very clean and efficient, but because it's smaller and lighter, it helps the F700 weigh 1700kg, whereas a base S280 is 1880kg.

• What about this fancy suspension?

You mean Pre-Scan. Mounted in the headlights of the F700 are two lasers that scan the road ahead. The hydraulically controlled active suspension then adjusts according to their feedback. Merc claims this gives the F700 a ‘flying carpet’ feel.

Pre-Scan also has a laser scanner in the base of the driver’s door and a hydraulic cylinder stops the door being opened should the car detect a possible collision.

• So what's all this about an avatar?

Mercedes calls its new system Servo-HMI. The F700 comes with an avatar, a virtual operating assistant. So rather than telling the car your destination, you can 'discuss' it instead. Quite why this needs discussion is another matter. And as an avatar is supposed to be your own persona in a virtual world, you might as well just talk to yourself.

Mercedes seems to have thought of this, though. Rather than rich bankers having to talk to themselves on the journey home – if they should happen be driving themselves – the avatar in the F700 is a young woman. No word yet on whether she can be personalized.

• What else should I know about the inside of the F700?

That if this car ever makes production you won't want to sit up front. At 5180mm long, it’s only 29mm shorter than a long wheelbase S-class. However, thanks primarily to the compact engine, the F700’s wheelbase is 285mm longer than the biggest S-class's. It’s very slightly lower than an S-class too but, because it's wider than the current S, there's lots of interior room.

This allows for Mercedes’ Reverse seat. The right rear seat (in this left-hand drive car) can split apart and move to face away from the direction of travel so that the two rear passengers can interact.

Two large glazed areas in the roof allow light in, while the interior trim is made from natural materials including leather and cork.

• The outside is somewhat challenging

Indeed, but apparently the F700’s design is ‘perfectly compliant with the brand identity of Mercedes-Benz’. To these eyes that doesn’t bode well, especially having seen the Ocean Drive concept as well.

The F700's design language is called ‘aqua dynamic’, though it isn’t quite as extreme of that of the 2005 Bionic Car concept. That car was heavily based on a Boxfish.
The doors of the F700 are asymmetrical, as the right rear door is a ‘suicide door’, a la Rolls-Royce.

• Anything else?

There’s a transparent cover over the rear wheels to improve aerodynamic efficiency. There are also recessed door handles and tiny wing mirrors. And those big 21-inch wheels are wrapped in low rolling resistance rubber that is said to be 17 percent less resistant than regular tires.

Why has Mercedes made this car? Because, apparently, with increased traffic in mega cities we need ‘mobile living spaces which afford the highest comfort on wheels’. So Mercedes has kindly built a large car to take up more space. And it's not exactly for the masses either...

Some of these technologies, especially Diesotto, are worthwhile, others are not. Either way, big Mercedes always point towards what the rest of us will eventually drive. This is the future.