Audi is proud to present the 1st 12-cylinder diesel engine in a series passenger car. This 6-liter V12 makes its debut in the Audi Q7 and it produces a colossal 500 PS and 1,000 Nm of torque, opening thus a new chapter in diesel history.
Featured in the new R10 Le Mans racing car, the V12 TDI 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 is provided with the world’s first 2,000 bar Bosch Common Rail System that ensures 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 power is transmitted through a new six-speed tiptronic gearbox to the quattro permanent 4-wheel drive system.
Despite its belonging to the Audi V-engine family, this model features a special cylinder angle of 60 degree – perfect for this engine type. Apart from the light and highly durable crankcase, a further highlight is the new chain drive assembly, including also the 2 newly developed high-pressure pumps in the common rail injection system.
A further technological breakthrough consists in keeping up to 2,000 bar of pressure within the 12 piezo injectors. Both performance and efficiency are optimized by this high injection pressure and the running smoothness also remains excellent. Exhaust emissions are also low. Conforming to the Euro 5 emissions class which, the twin-turbo V12 TDI will come into force in 2010. Fuel consumption is only 11.9 liters per 100 km. The diesel pioneers at Audi has thus opened new horizons in motoring with this high-tech 12 cylinder engine using TDI technology.
The World’s Most Powerful Diesel Passenger Car
For the last 3 decades Audi has stood at the forefront of diesel technology. Ingolsadt brand presents now a further world first – the 1st V12 diesel engine in a passenger car. Containing a wealth of pioneering technology, the new Audi Q7 V12 TDI is powered by a 12-cylinder diesel engine. With an outstanding 500 PS and 1000 Nm of torque, the 6-liter engine of the high-performance SUV provides the driving performance of a sports car.
The big performance SUV from Audi accelerates with impressive ease. The world’s first 2,000 bar Bosch Common Rail system provides superior power reserves in any situation. Impressive acoustics at the highest levels of driving comfort is ensured by the ultra-modern piezo-injection system.
Featuring extensive reinforcement, the new 6-speed tiptronic gearbox shifts quickly and comfortably. It transfers the enormous power to the quattro permanent 4-wheel drive system. Having an average fuel consumption of just 11.9 liters per 100 km and the 6 and 8-cylinder 3.0 TDI and 4.2 TDI engines, Audi diesel engines are highly dynamic.
Audi also rewrote the record books earlier this year on the racetrack. The premium R10 prototype sports car won every long-distance race it entered. These included the Le Mans 24 Hours road race.
The V12 race engine in the R10 squeezed 650 bhp from its 5.5-liter 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.
The Audi tradition is to transfer race car technology into series production. The FSI engine is the predecessor to the R10, the R8, notched up 5 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 RS4 and the V10 FSI in the S6 and S8.
Pioneering Technical Performance
Assembled in the plant in Gyor, Hungary, the new series-production V12 TDI reaches a still outstanding level of only 500 bhp. When designing the engine, engineers kept in their mind that the 6-liter engine would be a derivative of the current family of Audi V-engines, that up to mow were limited to 6, 8 and 10 cylinders. They transferred the basic findings from the race car to the series – production engine. The V12 TDI aggregate has a cylinder clearance of 90 mm, which is standard for engines of this type. However, the engine has a cylinder angle of 60 degree instead of 90 degree that leads to an elimination of inertia in this type of V12 design.
The total engine capacity of 5,934 cc 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 compact diesel engine measures 684 mm in length and is only 166 mm longer than the V8 TDI. These dimensions are the primary requirement for integrating the V12 TDI into the Audi Q7.
The crankcase of the V12 TDI is made from cast-iron with vermicular graphite which is known as GJV-450, already used in 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%.
Forged drom a chrome and molybdenum steel alloy, the crankshaft 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 aluminum.
Both cylinder heads are compared of 3 main elements. The lower section is made from a highly durable and light aluminum 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 actuated valves use 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.
Like most Audi V-engines, the maintenance-free chain drive is located on the back of the engine in a space-saving arrangement. Using a new layout the chain wheel of the crankshaft locks into the gearwheel. From here 2 simplex chains drive the camshaft. Two further chains drive the oil pump and both high-pressure pumps in the common rail injection system.
Both new double stomped high-pressure pumps are part of the new common rail injection system developed by the specialists at Bosch. Both pumps amass up to 2000 bar of pressure in the rails: only 1600 bar was usually achieved up to now.
Updating the piezo injectors with their 8-hole jets, an optimal spray is created in the combustion chamber through the high pressure. This in turn allows the ignition process to take place quicker and more homogenously, leading to a much better sound. Performance is also improved by the efficient combustion whilst reducing emissions and fuel consumption.
The current generation of inline injectors use the piezo effect meaning that when an electric current is created, piezo crystals expand in milliseconds. This expention is then directly transported (inline) by the V12 TDI injectors - containing over 100 piezo plates – to the injection nozzle needles without the use of mechanism in between.
By using piezo technology the number of injection processes per power stroke can be widely varied.
In addition to the main injection, pre and post-injections are possible. Pre-injections reduce the acoustic hardness of the combustion procedure. Post-injections serve to increase the temperature of the emissions, helping regeneration of both standard-fit particulate filters.
You can find the both turbochargers on the exterior of the V-engine, each supplied with a cylinder bank. Thanks to its adjustable guide vane geometry, the complete gas emission stream is always fed through the turbines. The changers respond even at low levels of revolution and reach high levels of efficiency.
Amassing a charge pressure of up to 2.6 bar, both turbochargers are a key aspect of the exceptional torque levels of 1000 Nm that are supplied to the V12 TDI constantly between 1750 and 3000 rpm. With its 368 kw (500 bhp), the diesel reaches a specific performance of 62 kw (84,3 bhp) per liter of engine capacity.
Two large charge air coolers reduce the temperature of the compressed air. The V12 is provided with a double-flow exhaust system with 2 particulate filters. The suction unit is built in a similar way – each cylinder bank contains an air filter behind which an air mass meter is stored. Two control units manage what happens within the engine according to the master-slave concept.
Conforming to the Euro 5 emissions, a reduction of nitrogen oxide emissions is demanded. Aside from the precise analysis of the fuel injection system through the common rail system, the Audi engineers have focused especially on exhaust gas recirculation. Up to 50% of emissions are recirculated through the air intake in order to reduce nitrogen oxide emissions. The large-dimensions recirculation system is stored in the upper section of the V cylinder and includes a water cooler which reduces emission temperature significantly.
Impressive not only with regard to technology, but also in terms of appearance, the Audi Q7 V12 TDI’s most striking visual changes are the underbody panels at the front and rear. The chrome-plated single-frame radiator grille evokes the tradition of the Audi S6 and S8. these 2 cars, with their V10 FSI engines, are the top sports models in their class. The vehicle features a powerful braking system which is every bit its equal.
Diesel Milestones from Audi
Being the pioneer in the diesel domain for over 3 decades, the Ingolstadt brand has reached a further milestone with the advent of the new V12 TDI. The new 2.5 liter 5-cylinder engine offered 88 kw (120 bhp) and 261 Nm of torque in 1989.
In 1994, an expanded version was produced with 103 kw (140 bhp). The engine was also available with the option of 4-wheel drive – the first TDI quattro. At the same time, a new 4-cylinder diesel engine was introduced in the Audi 100 and Audi 80, the now legendary 1.9 TDI with 66 kw (90 bhp)
Towards the end of 1995, the 4-cylinder achieved new heights of 85 kw (115 bhp) through the use of pump-jet injection. At the beginning of 1997, the world’s first 2.5 V6 TDI made its debut. This engine came with 4 valves per cylinder and reached 110 kw (150 bhp). With a top speed of 220 km/h the Audi A8 became the quickest series-production diesel on the market. The first 8-cylinder TDI followed in 1999, a V8 with a displacement of 3.3 liters. The 3.0 TDI was introduced in the spring of 2004, the first V6 diesel engine with inline piezo injectors in the common rail system.
The 4.2-liter TDI currently spearheads the TDI range from Audi. Introduced last year in the A8, every third A8 buyer in Germany decided to opte for the V8. The V8 TDI will also become available for the Audi Q7 during the first half of 2007.