In 2006, Audi brought its first TDI engine to Le Mans, and even though that 5.5 liter V12 monster didn’t win, it put the world on notice that diesel power was not just for heavy duty trucks any more. Audi has gone on to dominate endurance racing with its diesel-powered hybrid racers ever since, and the cars continue to get more and more efficient.
Fuel efficiency is a key component of Le Mans rules these days, so what was cutting edge in 2006 is hopelessly outdated in 2014. To meet the challenge of today’s rules, Audi will campaign its R18 e-tron Quattro racer at the Circuit de la Sarthe 24 hour race this weekend. This latest diesel hybrid car features a 4.0 liter V-6 engine that is a stunning 40% more fuel efficient than the 2006 engine. Yet despite such a dramatic increase in mpg, the 2014 car is just as fast on track as its predecessor.
Green Car Congress explains that in addition to the internal combustion diesel engine, the R18 has two on-board energy recovery systems. The ERS-K recaptures kinetic energy from the front wheels under braking, and that energy is converted into electricity and stored in a flywheel system alongside the driver. The ERS-H unit is an electrical generator powered by the engine’s turbocharger. Output from the ERS-H is added to the energy stored by the flywheel, and the combined energy from both is then used to provide additional acceleration at the driver’s discretion.
Corporate sibling Porsche will be back at Le Mans in 2014 after a 16 year absence. The Porsche 919 Hybrid will compete with an all-new turbocharged V-4 gasoline engine. Unlike the Audi flywheel system, the Porsche will store all the electricity from its ERS-K and ERS-H systems in on-board lithium batteries. Porsche also thinks it scored a coup when it signed former Red Bull Formula One driver Mark Webber to its driver line up for the race.
Endurance racing is a test of drivers and machines. Results are often more about reliability then outright fastest lap times. The winner is whoever completes the most laps within the 24 hours allotted, so time spent in the pits for refueling and mechanical repairs must be kept to a minimum.
Will Audi continue to rule Le Mans with its new R18 race car? Or will Porsche pull an upset in its return to the sport? At noontime on Sunday, (6 am EDT) we will know the answer.