Audi has revived the quattro name for its new hybrid Le Mans 24 Hours challenger. The hybrid version of the German manufacturer's turbo-diesel LMP1 coupe will be known as the R18 e-tron quattro. It takes the name because its hybrid systems recover kinetic energy and return it to the track through the front axle.
The R18 e-tron quattro follows in a line of successful Audi four-wheel-drive competition cars from the original Audi Quattro World Rally Championship winner of the early 1980s to its A4 quattro Super Tourer of the late 1990s. The car was unveiled in Munich on Wednesday evening, together with the conventional 2012-spec version, which has been christened the R18 ultra.
"To develop hybrid technology for Le Mans is at least as ambitious and challenging as our diesel project was in the early stages," Audi Sport boss Wolfgang Ullrich said. "The first results are very encouraging and we are intrigued to see just how this technology performs."
The R18 e-tron, which will also race in the new FIA World Endurance Championship, becomes a four-wheel-drive car within certain limits laid down in the Le Mans rulebook. The regulations allow 500kJ (approximately 70hp) of stored energy to be transferred to the wheels between two braking events at speeds above 75mph.
The rules allow energy retrieval on only one axle. The advantages of choosing the front wheels include improved traction and greater efficiency during the recovery process. Audi has chosen to use a flywheel or accumulator for energy storage rather than batteries or the super-capacitors favored by rival Toyota.
Christopher Reinke, Audi Sport's technical project leader LMP, said: "A high power density is crucial during energy recuperation. The accumulator must be capable of absorbing and lot of energy within a few seconds during the braking stage."
The flywheel has been developed by Williams Hybrid Power, which also produced the unit in sister marque Porsche's 911 GT3-R Hybrid.
The 2012 Audis will not race until the second round of the WEC at Spa in May. A revised version of last year's R18 TDI will be used in the Sebring 12 Hours series opener on March 17 when the German manufacturer enters three cars.
Audi will run its full four-car Le Mans lineup of two R18 e-tron quattros and two R18 ultras at Spa (see separate story). It will run one of each at each WEC round after the 24 Hours.