Audi has announced a smaller, lighter, "even more efficient" diesel engine for the June 2009 Le Mans 24-hour race. Alternative and fuel-saving power concepts will be a focus at the next Le Mans, and Audi plans to address the issues with the new LMP (Le Mans Prototype) 1 R15 TDI racecar. It will differ markedly from its predecessor, the highly successful R10 TDI, and will feature many technically innovative details, says the company. Three cars will be entered for Le Mans.
"The step from R10 to R15 is significantly larger than it was from the R8 to the R10," said Dr. Wolfgang Ullrich, Audi’s Head of Motorsport, who explained that only the basic concept was carried over from the previous racecar.
The R15 TDI is described rather oddly by Audi as being "an open-topped roadster," which makes it sound something of a boulevard cruiser, though it certainly is not. No further official details will be released until the car makes its public debut at the Sebring 12-hour race next March.
Michael Dick, Chairman of the Board for Technical Development and responsible for the Audi’s motorsport program, added: "We know just how important motorsport is for the success of the brand. Audi must also be present on the racetrack in economically hard times. It is all the more important for us to enter a motorsport category in which the cost-benefit calculation is positive."
That cost benefit centers both on winning races and on demonstrating the reality on which Audi’s "Vorsprung durch Technik" motto is founded, notably its powertrains and approach to the use of alternative fuels.
Wolfgang Hatz, Head of Powertrain Development for the Volkswagen Group, underlined the importance of alternative fuels including GTL (gas-to-liquid) technology: "Together with Shell, we have pushed GTL to the fore, and a percentage of the 2008 winning diesel Audi R10’s fuel comprised GTL. The fuel is very important as are other types, including LPG (liquid petroleum gas), which is very significant in China for taxis. We are introducing it for the Golf in Europe. CNG (compressed natural gas) is another significant alternative. The pressure on energy will mean that there will be a diversity of fuels in the future."
While biofuels plainly have a significant role, he does not believe that corn-based fuel is the right solution: "I think that is a mistake, but second-generation biofuels are a very good thing. Audi is very much focused on that area. We have a share (with Daimler) in SunDiesel manufacturer Choren Industries in eastern Germany, for the production of biomass, and a close partnership with clean renewable fuels developer, Iogen, in Ottawa, Canada, who produce ethanol from biomass including straw. We will have a variety of energies in the future."
Audi’s emphasis on diesel engines and the continuing potential of gasoline underlines the company’s confidence in both, and Hatz stressed that there was no prospect of a single ICE (internal combustion engine) solution combining both technologies: "There are some people who may believe that, but I do not think so: convergence is not for me."
Although VW has been researching a Combined Combustion System (CCS) engine, which does see the convergence of gasoline and diesel technology, Hatz said the company had not claimed it to be the single engine type of the future: "We will continue to have gasoline and diesel engines. But CCS may come into a range where we can burn middle distillates (although it can burn diesel). Gasoline will continue to need light distillates, and diesel, heavy."
Any radical engine changes would come slowly, said Hatz: "Today’s global car population is 600-800 million. So the change will take decades, and for a long time, we will need to feed today’s cars."
Diesels and turbocharged direct-injection gasoline engines would dominate the immediate future, but electric cars would be seen in "fairly large" numbers in 15-20 years.
Production diesels may not be classed as high-revving in a gasoline sense, but they are revving more highly than they were even two or three years ago. Audi’s TT diesel sports car signals a new direction; its engine can be revved close to 5000 rpm.
Will the diesel’s rev range open up still further? "We can run a diesel at 6000 rpm—we do on our racecar engine (although it was limited to 5500 rpm at Le Mans 2008)—but does it make sense for road cars if you look at our current gasoline TFSI (turbo/supercharged direct-injection) engines?" questioned Hatz.
"Those engines already have the power and torque very low down the rev range. So do they need to be revved to 6500 or 7000 rpm when they produce maximum output at 5000 rpm or less?" continued Hatz. "No. The Audi 1.8-L TFSI in the A4 produces maximum power of 88 kW at 3650 rpm, and this remains constant to the engine speed limit." Even more important is the value of lower-end torque with early upshifts to the next gear, he added.
As for Audi’s planned diesel advances, Hatz said that bi-turbos (one smaller and the second larger) would give greater lower-end torque: "Driveability will be unbelievably good!" Maximum torque spread could be from about 1400 to about 4700 rpm.
"To improve diesel emissions, we need as much air as possible; air management is another of the keys to handle enhanced EGR (exhaust gas recirculation) and improved combustion systems," said Hatz. "And we will see further downsizing."
Already, many 1.6-L diesels have comparable power outputs to previous generation 2.0-L units. Hatz sees this trend continuing, with 1.2-L Golfs as well as Audi A3s and A1s in five to seven years’ time, although the emphasis would be more on reducing emissions and increasing efficiency than generating higher power. "I do not see specific high-performance diesels in future as really necessary. There are certain power limits to meet Euro 6 emissions requirements."
He said that achieving the 130-g/km fleet target for 2012 was already very tough: "The French manufacturers may have very good CO2 figures, but their fleets are not as broad as ours; we are selling cars from the VW Fox to the Bugatti Veyron—and a Polo today is larger than the first-generation Golf! However, in our class, we are very competitive, and that will improve greatly. But you can’t just decrease emissions by 10% time after time—there are limits imposed by physics."
Complementing engine developments will be advances in transmissions, and double-clutch systems are already prominent across the VW Group’s model ranges. Although not officially confirmed by Audi, the next-generation A8, expected to be announced for MY2010, is likely to have an eight-speed torque-converter transmission. Other VW Group companies might also use it.
That just could include Bentley, whose lowest CO2-emitting model range is the Continental, producing 396 g/km, while the Arnage range, including the Brooklands, puts out 465 g/km.
Hatz and Bentley Chairman Dr. Franz-Josef Paefgen have houses next to one another, and it is reasonable to imagine that sometimes the two men continue their workday conferences at home, maybe over a drink and an apfel strudel.
"We will improve Bentley emissions quite a lot," said Hatz. "Using biofuels, we can achieve much lower emissions figures. We have to."
Could that need also mean using Audi’s next-generation 3.0-L diesel with bi-turbo technology rather than a gasoline hybrid (which is another possibility) even though Bentley sales are mainly in the still diesel-doubting U.S. car market? It could, because stranger things have happened in the automotive world; who would have thought even five years ago that a diesel Audi could beat Ferrari and Porsche to win at Le Mans?
So it is at least possible to imagine that the potential for diesels to power some of the world’s most high-profile luxury cars just may be discussed over the apfel strudels.