For two decades Audi has driven forward the advancement of diesel technology – from the very top. Now the brand with the four rings is presenting another world first: the first V12 TDI in a passenger vehicle. The diesel, which generates an output of 368 kW (500 hp) and 1,000 Nm of torque (737.56 lb-ft) from a capacity of six liters, gives the new Audi Q7 V12 TDI quattro the performance of a sports car. It catapults from zero to 100 km/h (62.14 mph) in only 5.5 seconds and has an electronically capped top speed of 250 km/h (155.34 mph). The V12 diesel is opening up entirely new horizons in the diesel sector. The big-performance SUV from Audi completes all intermediate sprints with fascinating ease; in every driving situation it boasts superior reserves of power. The engine captivates its drivers not only with its sheer inexhaustible power but also with its highly cultivated manner of operation – the subtle engine sound takes on a voluminous, strong note when the throttle is open. In terms of fuel consumption the six-liter TDI, which features a completely redeveloped common rail injection system, requires an average of only 11.3 liters/100 km (20.82 US mpg), substantially less than the gasoline units produced by the competition. No competitor is able to match this achievement.

Engine
The new twelve-cylinder TDI, produced at the Györ plant in Hungary, is a member of the current family of V diesel engines from Audi, which up to now was restricted to 6 and 8-cylinder units. As with other inline engines, it has a spacing of 90 millimeters (3.54 inches) between cylinder centers. Yet its included angle is 60 degrees, not 90 – the reason is that on this layout of V12, no free inertial forces or mass moments of inertia can then occur. The results are refined in every respect.

The 83.0-millimeter bore (3.27 inches) and 91.4-millimeter stroke (3.60 inches) of the twelve-cylinder are the same as the 3.0 TDI, producing a total displacement of 5,934 cc. The two cylinder banks are positioned opposite one another with an offset of 17 millimeters (0.67 inch). Measuring 684 millimeters (26.93 inches) in length the powerful engine is extremely compact, only 166 millimeters (6.54 inches) longer than the V8 TDI. This dimension was the key prerequisite for integrating the V12 into the Audi Q7.

The V12 TDI crankcase is made from 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 crankshaft forged from chrome-molybdenum alloy steel is mounted with the aid of an extremely rigid main bearing bridge made of nodular cast iron. The forged connecting rods are cracked and the pistons are made of aluminum.

The two cylinder heads are each made from three main elements. The base section is made from a high-strength, lightweight aluminum alloy, through which the coolant flows and where the intake and exhaust ports are incorporated. Above this are an oil-bearing upper section and a reinforcing ladder-type frame supporting the two camshafts. The valves are actuated by low-friction roller cam followers. The compression ratio is 16.0:1.

As usual on the Audi V engines, the no-maintenance chain drive is mounted on the reverse of the engine, where it occupies little space. However, it has a new layout: the camshaft’s sprocket engages in an intermediate gear via which two simplex chains drive the camshafts. Two additional chains drive the oil pump and the high-pressure pumps for the common rail injection system – an important innovation for the V12 TDI.