Audi proved the worth of its diesel engine technology with a win at the 2006 Le Mans, breaking new ground for the legendary endurance race. This year, Audi ups the ante with two cars using hybrid diesel-electric drive systems.
The drive technology, branded by Audi as e-tron, uses a V-6 turbo-diesel engine on the rear axle, and an electric motor on the front axle. Similar to Kinetic Energy Recovery Systems (KERS) being deployed in F1 racing, the Audi R18 e-tron quattro captures braking energy in a flywheel. The car can then convert the energy of the spinning flywheel into electricity, to drive the front axle.
Audi did not specify whether, similar to F1 KERS, the driver would call up the electric boost at the push of a button. The company does say that part of the challenge of building the new system involved designing power control electronics to balance the output of front and rear axles.
Two features of this system could make it another winner for Audi. Its inherent all-wheel-drive nature could give the Audi cars an edge in the corners. And, similar to how the higher fuel economy of the diesel engine allowed fewer pit stops in 2006, capturing and deploying braking energy should help the cars get better fuel economy. At Le Mans, fewer refueling stops is a solid victory strategy. That is, as long as Audi's technology holds up over 24 hours of to-the-limit driving.
Toyota announced last year that it would return to Le Mans in 2012 with a hybrid race car. Toyota's car will use a gasoline engine coupled to a hybrid electric drive system.
In 2009, Le Mans changed its regulations to allow brake energy recovery systems, such as those Audi will deploy.
Depending on the success of Audi's approach, this technology could trickle down to its production cars, and even find expression among Volkswagen's many brands, Audi being one of them.