pbr Volkswagen are claiming that their new concept car, the XL1, is the most fuel-efficient car in the world.br ppbr The car has been unveiled by VW's Executive Vice President, Dr Ulrich Hackenberg, at the Qatar Motor show in Doha.br ppbr It has fuel consumption levels of 0.9 litres per 100 kilometres and also features lightweight construction materials, very low aerodynamic drag and a plug-in hybrid, consisting of a two cylinder TDI engine.br ppbr Also unveiled at the show was the world's "first hybrid supercar" the Porsche 918RSR.br ppbr General Motors have also been displaying their Hybrid Cadillac, the XTS, which has been picking up Car of the Year awards in the United States, since its release late last year.br ppbr The XTS is part of General Motor's move to promoting greener technologies as was witnessed earlier this year by the Chevrolet Volt, GM's first general release electric car.