With Audi keen to further its e-tron electric technology, as seen recently in the Audi R8 e-tron and Audi A6 L e-tron, the German manufacturer has debuted two new diesel-hybrid R18 e-tron race cars destined for Le Mans at the Spa Six Hour race over the weekend.

The two Audi R18 e-tron Le Mans prototype cars ran alongside two diesel-powered Audi R18 ultras – with Le Mans wins in 2006, 2007, 2008, 2010 and 2011 repeatedly proving the strength of Audi's diesel performance. Audi claimed a 1-2-3-4 victory on the weekend with the conventional diesel cars taking the top two podium spots.

The electric quattro system developed for the R18 e-tron (pictured top) sees a V6 TDI engine drive the rear axle while the front axle is powered by recuperated energy and fed into a flywheel energy storage system that returns it to the front wheels under acceleration.

The idea is not a new one for the brand as Head of Audi Motorsport Dr Wolfgang Ullrich explained: "We started to think about the hybridisation of a Le Mans sports car relatively soon after the first TDI successes."