As with most iterations of the Audi R18 race car , this year’s e-tron quattro machine has just received a number of updates ahead of the 24 Hours of Le Mans . The endurance event is scheduled to take place in mid-June in France.
Unlike the version used throughout the 2014 World Endurance Championship, the Le Mans racer’s body has been optimized for minimal aerodynamic drag, an essential property on Circuit de la Sarthe — an unusual track that consists of several long straights and high-speed turns.
The Le Mans body might not differ much at a first glance, but a closer look reveals the Germans have altered the fenders, which now have opening on the inside instead of at the top, and elongated the body at the rear, with the wing no longer hanging above the diffuser. Lastly, the exhaust configuration has also been changed and the tail pipes are now located above the diffuser, instead of exiting to the right and left of the huge central fin.
Through these updates, the R18 e-tron quattro will be capable of higher speeds, and aim for faster laps and average race speed. Last year, factory driver Andre Lotterer achieved an average speed of 150.37 mph on his fastest lap.
Audi will field three teams in this year’s 24 Hours of Le Mans race with the goal of winning its fifth consecutive even and the 12th title since 2000.
The powertrain of the R18 e-tron quattro in Le Mans configuration remains unchanged, with a revised, V-6, diesel engine motivating the rear wheels and with an e-tron quattro hybrid system spinning the front axle.
Click past the jump to read more about the Audi R18 e-tron quattro Le Mans.
Toyota has returned to Le Mans with the TS030 Hybrid in 2012, failing to win the famed event for two consecutive years. For 2014 the Japanese will be racing the TS040 version, one that had a great start in the 2014 World Endurance Championship. The brand new race car is keeping its gasoline-electric drivetrain, but the naturally-aspirated V-8 engine is now mated to an Aisin electric motor that spins the front wheels.
Additionally, a DENSO inverter will be in charge of grabbing energy during braking and sending it to a super-capacitor for that extra power kick on the long straights. Toyota will field two TS040 Hybrids in this year’s 24 Hours of Le Mans. The driver lineup will remain unchanged from last year’s race, with Alexander Wurz, Nicolas Lapierre, Kazuki Nakajima, Anthony Davidson, Sebastien Buemi and Stephane Sarrazin sharing driving duties.
Porsche is returning to Le Mans after no less than 15 years, and their weapon of choice is also a hybrid vehicle. But unlike Toyota and Audi , Porsche has developed a 2.0-liter V-4 engine that delivers 500 horsepower at 9,000 rpm. The turbocharged four-pot, also a structural component of the chassis, is joined by an electric motor and an energy recovery system for additional boost. The former is mounted on the front axles and powers the wheels, while the latter uses thermal energy collected from the exhaust system to power a generator.
Two Porsche 919 Hybrids will be seen at the Circuit de la Sarthe next month, where they will be driven by Brendon Hartley, Marc Lieb, Timo Bernhard, Romain Dumas, Neel Jani and Mark Webber. Porsche had a poor start to the WEC season, with both cars retiring during the first race, but the Germans faired better during the second event and now rank second in the manufacturers’ championships, behind Toyota but ahead of Audi.
Gallery Porsche 919 Hybrid
Gallery Audi R18 e-tron quattro LMP1
The Audi R18 e-tron quattro uses less fuel than any of its predecessors. In addition to the powertrain, aerodynamics makes a significant contribution to achieving excellent lap times with low fuel consumption. At round two of the FIA World Endurance Championship (WEC) at Spa (Belgium), the second body version of the new Audi R18 e-tron quattro made its debut. It has less aerodynamic drag for the Le Mans high-speed circuit.
Even the timeline shows the close link between the race car’s aerodynamic development and its basic concept. The aerodynamicists of Audi Sport were involved in the determination of the concept for the current race car from the summer of 2012. “We typically begin with a rough initial layout,” explains Jan Monchaux, Head of Aerodynamics at Audi Sport. “The engine concept, the wheelbase and the schematic drawing of the vehicle provide us with the key data. We subsequently design the first basic aerodynamic shape. In the next step, we analyze its performance potential by means of CFD.” Computational Fluid Dynamics (CFD) calculates phenomena of fluid dynamics using model equations. In the initial development stage, this eliminates the need for considerably more complex wind tunnel tests. “We then continue to elaborate the strengths of the initial design step by step and reduce potential deficits in the process,” adds Jan Monchaux.
The aim pursued by the developers is always the same. “To achieve the efficiency targets defined by the regulations, it is necessary to find the perfect ratio between aerodynamic drag and downforce,” says Dr. Martin Mühlmeier, Head of Technology at Audi Sport. “Using multiple simulations, we try to clarify even before the first test whether or not the car generates sufficient downforce to achieve the desired cornering speeds. At the same time, it is necessary to prevent excessive aerodynamic drag because we have to be fast on the straights as well. Another challenge resulting from the 2014 regulations is to design the aerodynamics in a way that optimally complies with the specified consumption targets.”
The unusual track characteristics of the Le Mans circuit pose a special challenge. The track in Western France with its long straights and many high-speed turns allows extreme parameters. A year ago, Audi factory driver André Lotterer on his fastest race lap (3m 22.746s) achieved an average speed of 242 km/h.
For this reason, Audi has developed two variants: one body version with minimal aerodynamic drag for Le Mans and one for the other seven WEC tracks that require higher downforce. Even at first glance, the two body versions clearly differ from each other, as could be seen during their joint fielding at Spa. “Nearly all the relevant areas of the bodywork have been optimized,” explains Jan Monchaux. At the front, the modified fenders with openings on the inside instead of at the top are noticeable. The differences at the rear are conspicuous. The body is now flush with the rear wing and fully uses the maximum length of 4,650 millimeters. By contrast, the high-downforce version has a shortened body. The tailpipes differ as well. For Le Mans, they do not exit to the right and left of the central fin but at the body surface above the diffusor.
“The challenge of minimizing aerodynamic drag has further increased under the new 2014 efficiency regulations,” says Monchaux. In the simulation, Audi calculates a parameter for aerodynamic drag that must not be exceeded so that compliance with the consumption targets established by the regulations is ensured. At the same time, certain downforce parameters must be achieved in order to make good cornering speeds possible. “We have to achieve pinpoint accuracy in this case while in the past there was more room for maneuver,” says the aerodynamicist. At Spa, on May 3, both body versions were concurrently fielded for the first time. The measurements obtained for car #3, the Audi R18 e-tron quattro designed for Le Mans and driven by Filipe Albuquerque (P) and Marco Bonanomi (I) confirmed the assumptions made by Audi Sport. As a result, Audi is targeting the Le Mans 24 Hours in June with sophisticated aerodynamics.