|Audi R8 V12 TDI Concept|
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Audi is presenting a revolution in the top class at the Detroit Auto Show 2008 - the first 12-cylinder diesel engine in a high-performance roadgoing sports car. The V12 TDI with a displacement of six liters powers a concept car based on the Audi R8. This unit generates a huge 500 hp and 1,000 Newtonmeters (737.56 lb-ft) of torque. Audi is writing a new chapter in diesel technology with this power unit. Equipped with the expertise that Audi has built up through its motor sport activities, the R8 V12 TDI in matt "Grace Silver" embodies superb road handling, pioneering technology and fascinating design.
The V12 TDI is closely related to the engine in the Audi R10, the two-time Le Mans winner - so it catapults the Audi R8 into supercar terrain concerning performance too. It sprints from zero to 100 km/h (62.14 mph) in just 4.2 seconds and its top speed is well over 300 km/h (186.41 mph). The peak torque, reached at only 1,750 rpm, paves the way for effortless acceleration that is unrivaled even at this level.
The new V12 TDI belongs to Audi's family of V engines but has the ideal included angle for this engine type of 60 degrees between cylinder banks. Its highlights include the new chain drive layout that includes the two newly developed high-pressure pumps for the common rail injection system. Its sound is as thrilling as you'd expect in a sports car of this caliber. For all the subtle smoothness that typifies this design principle, the twelve-cylinder unit is full-bodied and equipped with energetic overtones that make no secret of its performance potential.
Thanks to their high performance and pulling power, all Audi TDI engines are ultra-dynamic sources of power. The brand has often enough demonstrated its sporty character in its production cars, especially the six- and eight-cylinder 3.0 TDI and 4.2 TDI. Audi has also been writing a new chapter in its success story on the racetrack since 2006. The diesel engine in the R10 sports prototype won its very first endurance race at Sebring, Florida, when it was pitted against an entire field of gasoline-engined challengers. But its most crucial victories were surely in 2006 and 2007 in the 24 Hours of Le Mans, when it simply outclassed the international elite.
The V12 TDI race engine in the R10 produces over 650 hp from a displacement of 5.5 liters, giving it the potential for a top speed as high as 330 km/h (205.05 mph) depending on the gear ratios. Its power and sturdiness immediately impressed both fans and experts, who were impressed by its restrained noise level. Unusual for a race engine, this powerful Audi diesel makes barely more than a whisper.
Long traditions of motor racing and production technology complement each other at Audi. The FSI engine of the R10's predecessor, the R8, captured five wins at Le Mans with a direct gasoline injection system. Audi is also looking to maximize the advantage by using the race-tested FSI principle in its production models. The latest examples of this are the V8 with high-revving concept in the RS 4 and the production version of the Audi R8.
The roadgoing version of the new V12 TDI is built at the Györ plant, in Hungary. And the R8 V12 TDI still has a massive 500 hp on tap. In developing the six-liter engine, it was a clear priority to integrate it into the current family of Audi V engines, of which many thousands of versions with 6, 8 and 10 cylinders have already been built - both gasoline and TDI.
Audi's engineers were in an ideal position to use their experience building the racing engine to develop the road version. Like the other power units in this range, the distance between cylinder bore axes on the V12 TDI is 90 mm (3.54 in.). Yet its included angle is 60 degrees, not 90 degrees. This means no free inertial forces or mass moments of inertia can occur with the V12. The results are refined in every respect.
The 83.0 mm (3.27 in.) bore and 91.4 mm (3.60 in.) stroke produce a total displacement of 5,934 cc - just like the 3.0 TDI. At only 684 mm (26.93 in.) long, this large diesel engine is very compact and just 166 mm (6.54 in.) longer than the V8 TDI. This compact length is key to accommodating the V12 in the midengined Audi R8.
The V12 TDI crankcase is made from gray cast iron with vermicular graphite - a high-tech material referred to as GJV-450 that is already used on the V6 and V8 TDI engines. GJV-450, made by a patented casting process, is about 40 percent more rigid and 100 percent more fatigue-resistant than gray cast iron. This enabled the developers to make its walls thinner, cutting its weight by around 15 percent compared with conventional gray cast iron. The two cylinder heads are each made from three main elements. These are a base section made from a high-strength aluminium alloy incorporating the intake and exhaust ports, an oil-bearing upper section, and a reinforcing ladder frame supporting the two camshafts.
The valves are actuated by low-friction roller cam followers; the compression ratio is 16.0:1. Map-controlled swirl variation of the combustion air has been adopted from the V6 and V8 TDI engines. This produces permanently optimized swirl concerning both emissions and high performance.
As is the case in the Audi V engines, the no-maintenance chain drive is mounted at the back of the engine, where it occupies little space. Its layout has changed on the new V12 TDI. The camshafts' sprocket engages in an intermediate gear via which two Simplex chains drive the camshafts. Two more chains drive the oil pump and the two high-pressure pumps actuate the common rail injection system. The two new dual-piston high-pressure pumps form part of the common rail injection system supplied by specialty manufacturer Bosch. The two pumps build up a pressure of up to 2,000 bar in the rails. The piezo injectors with eight-hole nozzles have also been fundamentally revised.
The R8 V12 TDI concept with matt "Grace Silver" bodywork looks even wider and more resolute than the core model. It shows its potential through its muscular proportions, accentuated wheel arches and even larger air apertures. The rhombuspattern cover on the air inlets and outlets is the hallmark of Audi's sporty top models and a familiar feature of the current RS generation. Typical of the side view of the R8 is the sideblade. Much wider in the bottom third, it visually accentuates the engine's position as well as acting as an enlarged air deflector.
The continuous aluminium spoiler lip that connects the front and rear diffusers with side air baffles below the enlarged sills also pays tribute to this version's highly developed dynamic talents. And yet the R8 is unmistakable for its powerful, elegant basic proportions. The selective but always precise use of lines is another typical Audi characteristic, as is the curved arc of the roof. One new aspect is the glass roof of the passenger compartment with two large transparent sections. These, together with the glazed engine compartment behind, create a radically new formal element. The unmistakable NACA duct in the middle of the roof is a functional detail that is normally reserved for racing cars. Its ingenious shape accelerates the air drawn in here for the two cylinder banks of the V12 TDI engine.
The interior's design is as sporty and exclusive as the exterior: the characteristic element here is the monoposto - an expansive arc running around the steering wheel and instruments, connecting the driver to the car. The interior consequently picks up on the dynamism of the R8 V12 TDI concept and gives it tactile expression in a form that is accessible the moment you climb in.
The three-spoke sport steering wheel of course remains the focal point of the car's controls. With a diameter of 365 mm (14.37 in.), it is both sportily compact and ergonomic in shape. The steering wheel rim has a flat lower edge. This is a further aspect of the auto racing feel in the Audi R8 V12 TDI, but one that also brings major functional benefits, facilitating entry and exit for the driver. The steering wheel is covered in fine Valcona leather, with a diecast magnesium core providing strength.
The start/stop button for the engine and the Drive Select switch with the Dynamic/Sport/Race settings are arranged on the steering wheel. The latter controls the engine and transmission electronics as well as the magnetic ride dampeners in each of three different modes. In Race mode, the instrument lighting changes from white to red. The navigation system shows a combined display with lap timer and navigation information for the racetrack being driven. Or supplementary information such as centrifugal force and boost pressure can be called up.
Concentrating on the essentials was the priority in the ergonomic arrangement of all Audi R8 versions. The most important consideration - particularly for highspeed driving - is short reach distances for all controls, to keep the time that the driver has only one hand on the steering wheel to a bare minimum. In typical Audi style the monitor is well within the field of view, and the elements of the MMI operating system are located directly below it.
Compared with the production version, the R8 V12 TDI concept's interior has much larger aluminium applications, especially around the center console. The many carbon fiber elements give the interior a decidedly sporty feel. The R8's exceptional everyday practicality for a sports car is maintained in the study vehicle's spaciousness, even though the longer engine takes up more room. The two occupants have the generous wheelbase of 2.65 meters (8.69 ft.) to thank for the interior comfort. This means the driver and passenger will always be able to find their perfect seated position, whatever their build. The view is also very good for a mid-engine vehicle. Narrow A-posts optimize the field of view to the front and sides.
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