Mercedes-Benz is developing a highly flexible three-seat Smart.

The plans, revealed in a series of patent drawings over several weeks and seen by Autocar, underline Mercedes' determination to build on its limited line-up of dedicated city cars.

See the Smart patent drawings here

Mercedes is reacting to increased competition from Toyota in the form of the iQ and the impending arrival of similar urban-based offerings from premium rivals Audi and BMW.

The new interior draws heavily on that used by McLaren in its mould-breaking F1 supercar, sitting the driver’s seat centrally up front with a pair of passenger seats set further back on either side of the cabin – an arrangement made possible by the retention of the rear-engined platform design used by today’s Smart Fortwo.

Early plans call for the unusual layout to be used in a replacement for the coupe and roadster pairing axed from Smart’s line-up back in 2005, after a run of 43,091 cars.

Merc/renault in Smart tie-up

The low-slung three-seater has been conceived as a sportier alternative to Smart’s upright second-generation Fortwo, with accommodation for up to three, along with limited boot space at the rear.

Nothing’s official at this stage, but Mercedes-Benz insiders contacted by Autocar suggest the new car could take the name 'Forthree' into showrooms by 2014 as part of plans to extend the Smart line-up into a complete range of models by the middle of the next decade.

The three-seat cabin incorporates a number of innovations aimed at solving the inherent problems in such a layout, including the long stretch upon entering and exiting the cabin.

Among them is a swivelling seat base as well as a transverse runner within the floor that allows the driver’s seat to be adjusted out towards the door. Patent application sketches obtained by Autocar also reveal a complex seatbelt arrangement for the driver.

The three-seat interior is housed within a new interpretation of Smart’s existing Tridion steel safety cell, with sturdy longitudinal and transverse members aimed at providing controlled deformation and added crash protection.

Although the patent applications do not make mention of the new car’s proposed mechanical package, Mercedes-Benz is already well advanced on a new line-up of modular three-cylinder petrol and diesel engines ranging in capacity from 800cc through to 1.4 litres.

Also in the pipeline is a new seven-speed dual-clutch gearbox. Both are planned to make an appearance in the third-generation A-class, due out in 2011, before making their way into other Mercedes-Benz models, including those from Smart.

Greg Kable

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