This is the F700, Mercedes-Benz's new showcase for a series of high-end features it aims to include on future production models, unveiled today at the Frankfurt motor show.
The dramatically styled large luxury saloon is said to plot a direct path to the next-generation S-class due out in 2012, with state-of-the-art engine and suspension technology as well as an advanced avatar-based controller system and radical new styling themes dreamed up by its US-based design studio in Irvine, California.
Mercedes describes the F700 as "a futuristic interpretation of the classic saloon" and predicts much of the technology it previews will begin appearing on production models within the next decade.
Radical new look
While officials are quick to play down the relevance of the new four-door's styling, sources we spoke to suggest various themes explored within its body are likely to be developed further before being committed to production. These include the bold front end and individual elements such as the prominent wheelarches and flowing C-pillars.
In a novel approach, Mercedes has provided the F700 with three conventional front-hinged doors and a fourth rear-hinged door at the rear on the right. That's designed to ease entry and exit for those seated in the right rear seat, which can be set either in the direction of travel or turned through 180 degrees.
At 5180mm long, 1960mm wide and 1438mm high, the F700 is a scant 25mm shorter but a considerable 90mm wider and 37mm lower than today's long-wheelbase S-class, and on a 285mm longer wheelbase, at 3450mm.
Frugal and fast
More than its radically styled exterior, it is the F700's compact variable-compression twin-turbocharged 1.8-litre four-cylinder DiesOtto petrol engine that Mercedes promises will have the biggest bearing on its future model range.
Claimed to offer the power, smoothness and low emissions of a typical petrol engine in combination with the torque, flexibility and frugal properties of a diesel, the new unit is capable of switching between two distinctively different ignition processes depending on the driving conditions.
When started, the aluminium block engine runs in so-called petrol mode, with an air/fuel mixture being injected into the cylinders and ignited by a spark plug. But once temperatures have risen sufficiently and the engine is under light loads it automatically switches to diesel mode, where the compression ratio is raised and the spark plug is deactivated in a move aimed at enhancing overall efficiency.
Despite its relatively meager capacity by luxury car standards, the F700's advanced engine punches well above its weight with an output that compares more than favourably with Mercedes' existing four-valve-per-cylinder 3.5-litre V6 petrol and 3.0-litre V6 common rail diesel units at a claimed 238bhp.