Audi shows Q7 V12 TDI with 1,000Nm of torque

While we love concept cars, and we’re enamoured with futuristic power train technologies, but we must admit that one of the most alluring vehicles at the Detroit (NAIAS) Motor Show was the diesel-engined, production-ready Audi Q7 V12 TDI. It’s now nearly two decades since Audi invented the TDI engine, so it’s nice to see the technology being presented it in an all-new high-tech, range-topping guise. Derived from the company’s all-conquering race car which won everything it entered in 2006, including the Le Mans 24 hour, the now production-ready version of V12 TDI engine produces 368 kW/500 bhp and 1,000Nm of torque.

The Audi Q7 V12 TDI raises the bar in the burgeoning sports utility vehicle segment. A time of just 5.5 seconds for the dash from zero to 100 km/h and an electronically governed top speed of 250 km/h give the high-performance SUV sports car calibre. The majestic V12 TDI power unit with its capacity of six litres endows the high-performance Audi Q7 SUV with sports car credentials. It is the harbinger of a wide-scale model initiative, as Audi seeks to make major inroads into the US market with its diesel models – courtesy of a new emission control technology which cuts emissions drastically. The engine limits its consumption to an average of just 11.9 litres/100 km.

Last year, Audi demonstrated the dynamic potential of diesel power in most memorable fashion on race tracks around the world. The V12 TDI in the R10 sports prototype unleashed in excess of 650 bhp and left its petrol-engined competitors in its wake in each of the eight races it competed in. Highlights of this winning streak included its triumph at the gruelling Le Mans 24 Hours as well as its victories in the LMP1 category of the American Le Mans Series.

The trend towards diesel engines is gathering strength all the time in the United States too. Audi is firmly convinced that the TDI engine represents the powerful and economical alternative for the future of motoring, and is therefore preparing a model drive to bolster this trend.

When working on the road-going version of the V12 TDI, which will be built in its Györ plant in Hungary, Audi drew on all of the know-how that underpins the racing engine. The range-topping diesel is the new flagship model in the Audi range of V engines, spanning petrol and diesel units with 6, 8 and 10 cylinders.

The V12 TDI's cylinders actually sweep a greater volume than the racing engine, which has a capacity of 5.5 litres. Its 5,934 cc are produced by a bore of 83.0 millimetres and a stroke of 91.4 mm, the same dimensions as the six-cylinder 3.0 TDI. The two banks of cylinders are positioned opposite one another with an offset of 17 millimetres. Measuring just 684 mm long, the V12 diesel has an extremely compact design. Indeed, its compact size was one of the key prerequisites for integrating the V12 into the Audi Q7.

The V12 TDI features the same 90 mm spacing between cylinders as the other models in the V engine series. However, the cylinder banks are placed at an angle of 60 degrees to one another instead of the customary 90 degrees. This particular V12 configuration suppresses all of the inertial forces and mass moments which would otherwise cause vibrations. Consequently, the engine's smoothness is flawless in every regard.

The V12 TDI's crankcase is made from a mixture of cast iron and vermicular graphite – Audi already uses this high-tech material, known as GJV-450, in the manufacture of the V6 TDI and V8 TDI. GJV-450, which is produced using a patented casting method, is around 40 percent more rigid than cast iron and twice as resistant to fatigue.

This enabled the development team to make the walls thinner, paving the way for a potential weight-saving of around 15 percent compared to conventional cast iron.

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