Audi shows Q7 V12 TDI with 1,000Nm of torque
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Image Gallery ( 7 images )Attached to the outside of the engine's V are the two turbochargers which each supply compressed air to one bank of cylinders. Their variable vane geometry ensures that the full exhaust flow is directed through the turbine at all times – the turbochargers offer fast response even at low rev speeds and attain a high degree of efficiency.
Both turbochargers generate up to 2.6 bar of absolute boost pressure and therefore have a vital role to play in achieving the formidable peak torque of 1,000 Nm which the new V12 TDI constantly has on tap between 1,750 rpm and 3,000 rpm. The diesel's 368 kW/500 bhp equates to a specific output of 62.0 kW/84.3 bhp per litre.
The temperature of the compressed air is reduced by two large intercoolers. The V12 comes with a double-flow exhaust system featuring two particulate filters. The intake system is similarly structured – for each bank of cylinders there is an air cleaner followed immediately by a hot-film air mass meter. Two control units operating based on the master-slave principle orchestrate proceedings inside the engine.
The Audi Q7 V12 TDI already complies with the Euro 5 emissions standard, which is due to come into force in mid-2010 and will make especially tough demands in terms of reducing nitrogen oxides. It was with this in mind that the Audi engineers devoted particular attention not only to the new common-rail system and its high-precision fuel metering, but also to the exhaust gas recirculation system.
At partial throttle, up to 50 percent of the exhaust gases are fed back into the intake air in order to reduce NOx emissions. The extensive recirculation system incorporates a water cooler which reduces the temperature of the exhaust gases sharply.
The awesome V12 TDI directs its power as standard to a fast-action, smooth-shifting new six-speed tiptronic transmission. From here, the forces flow to a quattro driveline, which splits the drive power 40:60 between the front and rear wheels under normal driving conditions. This results in slightly tail-heavy, sporty handling characteristics, exceptional agility and exemplary steering precision.
To ensure that its phenomenal performance can be safely harnessed, the Audi Q7 V12 TDI is equipped with powerful, ventilated disc brakes. The ESP dynamic handling control system features a hill descent assist as well as a special off-road mode. The safety specification is rounded off by the pairs of front, side and head airbags in the interior.
An elaborate double-wishbone independent suspension has been used for each of the four wheels, while the majority of the axle components are made from aluminium. The adaptive air suspension, incorporating an electronically controlled damper system, comes as standard, creating a perfect synthesis of sporty handling on the one hand and silky ride comfort on the other. The body's ride height can be adjusted from its starting position of 180 mm above the ground up to the lift mode offering a whole 240 mm of ground clearance. The Audi Q7 V12 TDI study rides on 20-inch cast aluminium wheels.
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