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Saturday, January 26, 2008

Audi Q7 V12 TDI

Audi is proud to present a world first – the first twelve-cylinder diesel engine in a series passenger car. This six-litre V12 makes its debut in the Audi Q7. It produces a colossal 500 PS and 1,000 Nm of torque. With this engine Audi has opened a new chapter in diesel history.

The V12 TDI is reminiscent of the engine featured in the new R10 Le Mans racing car – it catapults the driving performance of the Audi Q7 into the echelons of top-class sports cars. The car sprints from 0 to 100 km/h in just 5.5 seconds, and has an electronically governed top speed of 250 km/h. Maximum torque is available from just 1,750 rpm. The high-tech diesel engine, with the world’s first 2,000 bar Bosch Common Rail system, provides the high-performance Audi SUV with superior power reserves in any situation. The impressive sound of the new Audi is provided by the ultra-modern piezo-injection system. The V12 TDI transmits this power through a new six-speed tiptronic gearbox to the quattro permanent four-wheel drive system.

Although the V12 TDI belongs to the Audi V-engine family, this model features a special cylinder angle of 60° – perfect for this engine type. Apart from the light and highly durable crankcase, a further highlight is the new chain drive assembly. This includes the two newly developed high-pressure pumps in the common rail injection system.

Up to 2,000 bar of pressure is kept within the twelve piezo injectors – a further technological breakthrough. Both performance and efficiency are optimised by this high injection pressure, and the running smoothness also remains excellent. Exhaust emissions are also low. The twin-turbo V12 TDI conforms to the Euro 5 emissions class which should come into force in 2010. Fuel consumption is only 11.9 litres per 100 kilometres. With the high-tech twelve-cylinder engine using TDI technology, the diesel pioneers at Audi have opened new horizons in motoring.

Twelve cylinders in the Audi Q7

Audi has stood at the forefront of diesel technology for the last three decades. The Ingolstadt brand now presents a further world first – the first V12 diesel engine in a passenger car. The new Audi Q7 V12 TDI is powered by a twelve-cylinder diesel engine containing a wealth of pioneering technology. With an outstanding 500 PS and 1,000 Nm of torque, the six-litre engine of the high-performance SUV provides the driving performance of a sports car.

Sprinting from 0 to 100 km/h in just 5.5 seconds and achieving an electronically governed top speed of 250 km/h, the Audi Q7 V12 TDI is catapulted into the echelons of top-class sports cars. New horizons have been set in the diesel market thanks to this outstanding power. None of our competitors can offer a comparable engine.

The big performance SUV from Audi accelerates with impressive ease. Superior power reserves in any situation are provided by the world’s first 2,000 bar Bosch Common Rail system. The ultra-modern piezo-injection system offers impressive acoustics at the highest levels of driving comfort.

Exceptional comfort

The new six-speed tiptronic gearbox, which features extensive reinforcements, shifts quickly and comfortably. It transfers the enormous power to the quattro permanent four-wheel drive system. The new Audi Q7 V12 TDI has an average fuel consumption of just 11.9 litres per 100 kilometres.

All diesel engines from Audi are highly dynamic thanks to their high performance and high torque characteristics. Audi has often proved its sporty character in series production, most recently through the six and eight-cylinder 3.0 TDI and 4.2 TDI engines. Audi also rewrote the record books earlier this year on the racetrack. Following its debut in Sebring, Florida, the premium R10 prototype sports car won every long-distance race it entered.

These included the Le Mans 24 Hours road race, probably the most difficult race in the world for both man and machine.

The V12 race engine in the R10 squeezed 650 bhp from its 5.5-litre engine capacity, reaching a top speed of 330 km/h. The power and endurance of the R10 was an immediate hit with fans and experts alike. However, what completely surprised them was the sound of the engine: unlike most racing engines, the powerful Audi diesel engine runs whisper-quiet.

Transferring race car technology into series production is an Audi tradition. The FSI engine in the predecessor to the R10, the R8, notched up five victories in Le Mans with its petrol direct injection. Audi has already transferred FSI performance to the production line. The most recent examples of this are the high-revving V8 in the RS 4 and the V10 FSI in the S6 and S8.

Pioneering technical performance

The new series-production V12 TDI, assembled in our plant in Györ, Hungary, reaches a still outstanding level of “only” 500 bhp. When designing the engine, it was kept in mind that the six-litre engine would be a derivative of the current family of Audi V-engines, which up to now were limited to six, eight and ten cylinders. The basic findings from the race car were of course transferred to the series-production engine. The V12 TDI aggregate has a cylinder clearance of

90 mm, which is standard for engines of this type. Nonetheless, the engine has a cylinder angle of 60° instead of 90°, leading to an elimination of inertia in this type of V12 design. Driving comfort is thus ensured in every situation.

The total engine capacity of 5,934 cm3 is derived from a bore measurement of 83 mm and a stroke of 91.4 mm, exactly the same as that of the 3.0 TDI. The large diesel engine is extremely compact. Measuring 684 mm in length, it is only 166 mm longer than the V8 TDI. These dimensions are the primary requirement for integrating the V12 into the Audi Q7.

The crankcase of the V12 TDI is constructed from cast-iron with vermicular graphite. This high-tech material, known as GJV-450, has already been used in the V6 and V8 models.

Produced in a patented casting procedure, GJV-450 is around 40 % more rigid and 100 % more fatigue-resistant than grey cast iron. This allowed the developers to reduce the wall thickness. The weight potential compared to conventional grey cast iron is around 15 %.

The crankshaft, forged from a chrome and molybdenum steel alloy, is held by an extremely rigid main bearing bracket made from cast iron reinforced by nodular graphite. The forged piston rods are cracked, whilst the forged pistons are made from aluminium.

Both cylinder heads are composed of three main elements. The lower section is made from a highly durable and light aluminium alloy where the intake and escape channels are integrated. The upper section guides the flow of engine oil, whilst both camshafts are stored within a reinforcing ladder frame.

The valves are actuated using low-friction roller cam followers with a compression ratio of 16:1. The engine characteristic swirl variations of combustion air were taken from the V6 and V8 TDI engines. The optimum swirl with respect to emissions and simultaneous high performance can therefore be set.

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Related entries:

Audi Q7 In Depth
Audi Q7 V12 TDI Concept at NAIAS
Audi Q7 V12 TDI to launch in 2008
Leaked: Audi R8 V12 TDI Study for Detroit


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