The Le Mans 24 Hours endurance race is perhaps the ultimate laboratory for automotive innovation. On the venerable Circuit de la Sarthe, carmakers have field-tested – indeed, torture-tested – systems and technologies that will continue to influence production cars for years after the chequered flag has waved.
The Federation Internationale de l'Automobile (FIA) and Le Mans organisers understand this is, first and foremost, an epic race of automotive endurance. But they also feel they have a greater purpose to further development of energy-efficient cars. More than a simple test of speed, Le Mans is a contest of going faster and farther on a given allotment of fuel: a meritocracy where cylinder count, engine configuration and fuel choice shouldn’t matter.
That quest for decreased fuel consumption has also benefited two other completely different areas of the car: ergonomics and aerodynamics. Lighting at Le Mans has always been a challenge, since at least six hours of the race happens in total darkness. For 2014, Audi employed laser-powered headlamps to give drivers the greatest edge possible.
With all these factors in mind, BBC Autos shadowed the Audi Sport team, tagging along with Audi head of engine design Ulrich Baretsky and three-time Le Mans winner Allan McNish, to uncover all these elements – fuel use and engine efficiency, aerodynamics, lighting and ergonomics – which will all sooner or later see the light of day in a production car.
On 14 June, they also translated to an epic 13th Audi win at the Circuit de la Sarthe.
- monitoring and real-time data
Because fuel is now the regulated element rather than airflow, as it has been for many years, knowing the car's fuel consumption during the race is a top priority for team and driver – and for the officials as well. This is also common sense for how production-car owners drive in daily life. You don’t go to an "air" station to refuel your car, after all.
With fuel as focus, Audi designed an all-new 4-litre, 120-degree V6 turbocharged diesel engine for the R18 E-tron Quattro. Audi first brought a diesel to Le Mans in 2006 to use a fuel-sipping strategy with fewer pit stops. Diesel engines are more thermally efficient; they expel less energy in the form of exhaust heat than petrol engines, so in an endurance race, diesels can have an advantage.
Current Audi TDI engines use very high fuel and injector pressures (2,000bar, or 29,400psi) to achieve high efficiency, a preference that stemmed from of the company's earlier engines that debuted at Le Mans in 2001. The high-pressure fuel systems in some road cars are direct descendants of these breakthroughs. Fuel pressure will go even higher in the future.
Baretsky: “It’s our job in motorsport to not respect manufacturing rules and conventions. We must come up with alternatives in the quick-turnaround environment where we operate to gain the best advantage to win races. Production-car engineers do not have that freedom.”
- multifunction display
- simple indicator lights
Drivers of the winning Audi R18s are presented with reams of information, much of it regarding fuel use. How that information is presented consequently becomes paramount; nobody wants to overload a driver negotiating a turn at 160mph in a lashing rain. But fuel use and flow per lap influence how that driver actually drives. Coloured lights on the steering wheel indicate over/under balance on permissible fuel use, and a resourceful driver can conserve fuel by coasting at the highest-speed portions of the track, thereby recovering energy and picking up mileage.
McNish: "The ability of imparting information to the driver is critical now because that information on fuel use will determine how he drives. The steering wheel used to be a device to turn the front wheels. Now it’s got lots of adjustments and indicators but you’ve got to know where everything is without looking. It’s all got to be done by feel because when you’re honkin’ up to that first chicane at 210mph, you kinda need to be looking at the 100m braking board. So it’s changed in that you need to use as little brain capacity as possible to drive the car round the circuit and use the rest of it and hopefully a large part of it for other things.”
- dual-concept (LEDs with laser)
- production car debut this summer
Audi essentially owns the conversation around vehicle lighting. Whether it’s throwing as much useful light at night in front of drivers, or the nearly blinding bright white walls of their global auto show stands, Audi is not subtle about vision. It has introduced another lighting system on the new R18 racecar to complement the existing LEDs from years past.
A blue laser runs through a crystal lens that casts a white beam very close to the colour temperature of sunlight. Swivelling headlights on road cars is nothing new, but using a laser to do so is.
Audi also claims the laser lights' beam reaches twice as far up the road. The lasers operate in addition to existing LED high beams.
This is not just a racing exercise. A production version of this system, where the lasers are active only above 37mph, was recently announced for the Audi R8 LMX Edition sports car. However, as with Audi’s sequential turn signals and Matrix Beam lighting, arcane regulations do not allow them for sale in the US. Indeed, there has been a battle royale between Audi and BMW to be the first manufacturer offering laser lights on a road car. With the R8 LMX hitting the European market this summer, Audi will beat BMW by a few months, as the i8 model goes on sale this fall.
McNish: "Imagine that in 1998, we were driving around here 20 seconds slower in lap times, but 20mph faster in absolute top speed. So where's the difference? Cornering speeds. Here at Le Mans, if you can get up to your top speed as quick as possible and get round the corners faster than your competitors, you've got a real advantage. If better vision at night helps your cornering speeds rise, then as a driver, I say 'gimme light!'"
- low drag at high speed = better efficiency
Cheat the wind and you not only go faster, but you burn less fuel doing so. And of all the tracks in the world, Le Mans is still the fastest with prototype cars doing a lap average speed – yes, average – of about 150mph. Aerodynamic refinement is consequently as important as that for fuel.
But the circuit at Le Mans is not just flat-out straight track. A very large portion of any one lap is spent negotiating high-speed corners where downforce is key. Rules this year have banned the blown diffuser where exhaust is routed through the downforce-generating cavity under the rear of the car, which Audi used last year. However, rules now permit a front-mounted wing: Le Mans giveth and Le Mans taketh away.
This extreme aero environment will pay dividends in production cars where burgeoning undercar airflow research picks up with lessons learned in motorsports and where wings, flaps and moveable elements will spring up, as on a possible future S3 sports sedan.