Audi's turbodiesel, electric flywheel hybrid, all-wheel drive prototype race car

Audi has disclosed some of the details of its forthcoming R18 e-tron quattro, revealing a turbodiesel, electric flywheel hybrid, all-wheel drive prototype, and ensuring that the 2012 Le Mans 24 Hour Race will be a battle of the hybrids.

Though Audi's long-time rival Peugeot will not contest the race, Toyota is entering two hybrid race cars in the prototype class, as will Audi, and with Audi's plans for hybrid and electric e-tron road vehicles, the battle for the title of the world's fastest racing hybrids is now on.

And as an added side-show, two TDI Audi R18 ultras will contest the event - the cars are identical to their hybrid brethren apart from the hybrid system itself - so we'll really be able to see how much difference a hybrid makes to performance, particularly as a four-wheel drive vehicle which should offer much superior roadholding when it rains.