The Volkswagen XL1 was born out of the company’s desire to build an ultra-efficient vehicle to be able to travel 100 km on only one liter of diesel fuel or around 240 U.S. mpg. The first concept was shown to the world in 2002, with an improved model, dubbed L1, showcased in 2009. The study gained the XL1 shape we’re all familiar with in 2011 as a diesel plug-in hybrid prototype. An updated production version rolled out in early 2012, when Volkswagen announced a limited-edition car will be built starting 2013. The XL1 is propelled by a 0.8-liter, two-cylinder TDI engine rated at 48 horsepower and an electric motor generating 27 ponies. The XL1 is expected to achieve a fuel economy of 260 mpg using both units, and return 120 mpg on diesel fuel alone. The all-electric range sits at 31 miles. As the 250 units slated to hit public roads are still being assembled as of October 2014, the company has developed a brand-new iteration of the XL1, named XL Sport.