Powerful, spontaneous and highly efficient – Audi is now equipping the Q7 with the company’s most powerful V6 engine. The 3.0 TFSI combines gasoline direct injection with mechanical forced induction via a supercharger. Two versions of the supercharged three-liter V6 are used, and both are impressively efficient: they each consume only 10.7 liters of fuel per 100 km (21.98 US mpg) in the EU cycle.

The base version of the 3.0 TFSI produces 200 kW (272 hp) and 400 Nm (295.02 lb-ft) of torque, the latter constant from 2,150 to 4,780 rpm. It powers the Q7 from zero to 100 km/h (62.14 mph) in 7.9 seconds on the way to a top speed of 225 km/h (139.81 mph) (in the version with air suspension). The more powerful version of the 3.0 TFSI delivers 245 kW (333 hp) and 440 Nm (324.53 lb-ft) between 2,900 and 5,300 rpm. Here the standard sprint is completed in 6.9 seconds; top speed (with air suspension) is 245 km/h (152.24 mph).

The brand with the four rings has a long tradition of supercharged engines.

The legendary Grand Prix racing cars built by Auto Union back in the 1930s already featured compressors, which coaxed as much as 440 kW (around 600 hp) out of the mighty 12-cylinder and 16-cylinder engines. Today the mechanical supercharger is once again current – as the perfect forced induction technology for the three-liter gasoline engine.

The compressor is so compact that it easily fits inside the 90-degree V of the cylinder banks in place of the intake manifold. It is driven by the engine via a Poly-V belt and can deliver its full boost right from idle. The gas pathways downstream of the compressor are very short, thus the torque develops extremely quickly. The 3.0 TFSI responds sportily to the throttle, and feels agile and snappy.

In the Audi V6, the compressor is located downstream of the throttle valve. In view of the low density of the intake air at engine loads below supercharging level and when coasting, its rotors are free-running and the amount of power required to drive them is low. Inside of the Roots blower, two four-vane rotary pistons counter-rotate at a speed of up to 23,000 rpm, with an air gap between them measuring just a few thousandths of a millimeter. The rotors can deliver 1,000 kilograms (2204.62 lb) of air per hour and compress it with a boost pressure of up to 0.8 bar.

Two water-to-air intercoolers made from aluminum and connected to a separate coolant circuit are integrated into the housing. Here, the compressed and thus heated intake air is cooled down again in order to increase the mass of air required for the combustion process. An extensive package of measures reduces compressor noise to a minimum.

The 3.0 TFSI is a member of the Audi V-engine family. Among its characteristics are systematic lightweight construction – the three-liter engine’s crankcase, which is made from cast aluminum/silicon, tips the scales at just 33 kilograms (72.75 lb). The entire engine, including the compressor, weighs 189 kilograms (416.67 lb). The bore measures 84.5 millimeters (3.33 in), the stroke 89.0 millimeters (3.50 in) and displacement is 2,995 cc.

The 3.0 TFSI features an entire package of refinements. The crankcase has been adapted to the higher prevailing pressures and all components are optimized for low friction. The two intake camshafts can be adjusted through 42 degrees crankshaft angle. In the intake ports, tumble flaps induce movement in the incoming air to promote optimum mixture preparation.

A common rail unit injects the fuel directly into the combustion chambers at a maximum pressure of 150 bar through six-port nozzles. Direct injection enables the engine to have a high 10.5:1 compression ratio, which also makes a major contribution to efficiency.

Click the title for the source