Audi unwraps Sportback concept in Detroit

The new Audi Sportback concept has Detroit in a spin this week with a seamless blend of sports coupe desirability and five-door hatchback practicality that has made it one of the undisputed stars of the 2009 North American International Automobile Show.

The sleek five-door GT is the latest in a long line of Audi design studies, many of which have transferred virtually unchanged to the production line, and not only offers a glimpse of Audi's future design vocabulary, but also raises the stakes technologically with a new 47 mpg-plus TDI engine featuring the world's cleanest diesel technology.

The Sportback concept is a variation on the theme first defined in the Audi range by the A3 Sportback and signals the brand's intention - as previously demonstrated by the A1 Sportback concept - to dramatically expand its line-up of Sportback models.

Power comes courtesy of a new version of the acclaimed 3.0-litre V6 TDI. In its latest guise, this advanced unit can lay claim to offering the world's cleanest diesel technology thanks to numerous new efficiency optimisation measures that not only give it the potential to provide up to 47.8 mpg, but also to meet the emissions limits of all 50 US states and the forthcoming EU6 standard.

These measures include a downstream exhaust emission control system, which by injecting a biological additive called 'Ad Blue' upstream of the Denox catalytic converter helps to reduce harmful nitrogen oxide emissions by up to 90 per cent, and unique combustion chamber sensors that enable even more precise regulation of the combustion process - another world first for Audi.

More familiar components, including the piezo common rail injection system, highly efficient exhaust gas recirculation, optimised turbocharging and a highly efficient, regulated diesel particulate filter also help to significantly reduce raw engine emissions.

Thanks to its low emission levels, this modern direct-injection diesel engine can be put into service anywhere in the world, even in California, which has the world's most stringent emissions limits. Compared with the fleet average of the petrol engines typically found in the US, the TDI boasts a fuel-efficiency advantage of up to 40 per cent.

The Audi Sportback concept is equipped with ceramic brakes on all four wheels for effective deceleration even under the most demanding conditions. Compared with conventional steel disks, ceramic brakes not only last four times longer, up to 186,411 miles, but also offer high resistance to fading.

As with the exterior, the interior of the Sportback concept is characterised by the emphasis on horizontal lines and large surfaces.

This is especially true of the wide centre console - stretching from the dashboard to the back - which seems to be a pure expression of function. The flat display of the MMI system is realised as a retractable system in the show car. When the ignition is activated, it extends horizontally from a slot above the central air register before moving in an elegant arc into a vertical, easy-to-read position.

The large glass roof underscores the width and feeling of spaciousness, and the sumptuous oak blockboard trim and unusually liberal use of leather - which envelopes everything from the dashboard and headlining right through to the boot - emphasises the study's brief as a luxury grand tourer in the traditional sense.