Audi Brings Quattro Back to Le Mans

Audi will have several R8sAudi R8 LMS UltraGermany, 2012 > present6 photos
racing in the Nürburgring 24 Hours this weekend, but the real race that it is getting ready for is the R18 E-Tron QuattroAudi R18 e-tron quattroGermany, 2012 > present8 photos
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at the 24 Hours of Le Mans on June 16 and 17. It will be the first time since 1998 that an all-wheel drive wil have competed at Le Mans

“Soon after the TDI phase had begun we started to think about the hybridization of a Le Mans sports prototype, when it was foreseeable that the regulations would open up this option. After exploring the concepts we quickly saw the opportunity of bringing a new technological specification of all-wheel drive back into motorsport. Unfortunately, it had been banned from circuit racing since 1998," said Head of Audi Motorsport Dr. Wolfgang Ullrich.

Audi and all-wheel drive are closely linked. From 1981 to 1997, Audi Quattro cars won four WRC titles, three Pikes Peak victories, a championship in Trans-Am, two DTM championships, 11 Super Touring Car Championships and a Touring Car World Championship title. The FIA banned all-wheel drive race cars in circuit racing in 1998. 

Audi found a loophole in the all-wheel drive regulations this year by fitting the hybrid system to the front axle and setting it up only to work above 120km/h. Despite the R18's relatively large size, the hybrid system had to be packaged around the driver's carbon fiber monocoque and front suspension components. There are also safety concerns with having a flywheel-based hybrid system too close to the driver. Audi also had to work to reduce the car's weight as much as possible to stay competitive. 

The R18 E-Tron Quattro poses with the original Audi Quattro

© photo courtesy of: Audi

The hybrid system works by converting braking energy to electricity which is used to drive a carbon fiber flywheel that sits beside the driver. The flywheel rotates at 45,000rpm and can supply up to 204hp to the front axle.

"After presenting our concept to the ACO and the FIA for the first time we received a relatively quick response. They saw that in the case of our hybrid solution in combination with all-wheel drive the Quattro factor certainly carries some weight. The FIA wanted to keep this within the limits of a reduced scope because its chief aim is hybridization, not the return of all-wheel drive. Therefore, a clause in the regulations was agreed that limits the advantage of a standard Quattro drive when accelerating out of tight corners. The electrified axle may only be additionally used for acceleration above a speed of 120 km/h," said Dr. Ulrich.

The FIA also ruled that hybrid cars must carry a 58l fuel tank, which is 2.0l smaller than on other LMP1 cars, and the hybrid system may only recuperate 500kJ (138.9 Watt hours) between two corners. 

This is the first time that Audi has admitted to the power created by its hybrid system. Now if ToyotaToyota TS030 HYBRIDJapan, 2012 > present5 photos
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would only release the figures from its capacitor-based hybrid system, a good comparison of the cars would be possible.

Given the problems that the Toyota team has been facing, it seems unlikely that it will challenge for the win at Le Mans this year. The real competition now is within the Audi team. Will the lighter R18 UltraAudi R18 ultraGermany, 2012 > present11 photos
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win again like in the 6 Hours of Spa or with the R18 E-Tron Quattro prove its worth in the longer, 24 hour race?

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