18 September 2006

Audi is launching a new model Q7—the most powerful diesel passenger car featuring a 12 cylinder TDI engine which is based on the V12 unit that powered the Audi R10 TDI to its victory at the Le Mans race earlier this year. The new engine has been designed to become a derivative of the current family of the Audi V engines, which includes six, eight, and ten cylinder units.

The new V12 engine develops 365 kW (500 hp) of power and 1000 Nm of torque, which is available between 1,750 and 3,000 rpm, making it possible for the model Q7 to accelerate from 0 to 100 km/h in 5.5 seconds. The maximum speed is electronically limited to 250 km/h. The average fuel consumption of the Q7 is only 11.9 l/100 km.

The engine displacement of 5,934 cm3 is derived from a bore of 83 mm and a stroke of 91.4 mm, the same as that in the 3.0 TDI. The V12 is very compact, measuring 684 mm in length—only 166 mm longer than the V8 TDI. The crankcase of the V12 is made from cast iron with vermicular graphite, a material known as GJV-450 which has also been used in the V6 and V8 units.

A new common rail fuel injection system for the V12 has been designed by Bosch. The system features two high pressure pumps that develop up to 2,000 bar of rail pressure, and eight-hole piezo injectors. The air charge system includes two turbochargers with a load pressure up to 2.6 bar.

The Q7 conforms to the proposed Euro 5 emission standards. PM emissions are controlled using two particulate filters regenerated through an engine management strategy. High rates of cooled exhaust recirculation—up to 50% at partial load—are used for NOx control.

Source: Audi