New engines and eight-speed gearbox for Audi Q7

The two gasoline engines, both V6 units but with different power outputs, are new, and so is the second-generation V6 TDI. A mighty V8 diesel completes the range. All the engines for the Q7 combine two technologies: forced induction and direct fuel injection. A high-performance recuperation system that recovers energy during braking is also a standard item with all six- and eight-cylinder engines.

The new 3.0 TFSI gasoline engine embodies Audi’s downsizing strategy: replacing engine displacement with supercharging. Within the 90-degree angle formed by its cylinder blocks there is an engine-driven supercharger that compresses the intake air. Two charge-air intercoolers prevent the air temperature from rising, so that the engine draws in more oxygen for the combustion process. Vigorous thrust and spontaneous throttle response make the 3.0 TFSI engine, with its sonorous note, an ideal source of power for the large high-performance SUV from Audi.

Two versions of the supercharged V6 are available. The basic version develops 272bhp and has a maximum torque of 400Nm over a broad engine-speed range from 2,250 to 4,750rpm. It accelerates the Q7 in 7.9 seconds from a standing start to 100km/h and gives it a top speed of 222km/h, or 225km/h with adaptive air suspension.

The more powerful version of the 3.0 TFSI delivers 333bhp and a torque of 440Nm between 2,900 and 5,300rpm. 100km/h are reached in 6.9 seconds, with powerful forward progress continuing until 243km/h are reached; with adaptive air suspension the top speed is 245km/h. Both versions of the 3.0 TFSI are impressively efficient: in the EU fuel consumption test cycle they are content with 10.7 liters per 100 kilometers. Compared with the previous engines, the 3.6 FSI and the 4.2 FSI, fuel consumption has been reduced by 1.4 and 2.0 l/100 km – 12 and 16 percent respectively.

The second-generation 3.0 TDI, a new development, has effectively nothing in common with its predecessor – apart from plenty of power! It has a rated output of 240bhp and a constant 550 Nm of torque all the way from 1,750 to 2,500rpm. This V6 diesel accelerates the Q7 from a standstill to a typical main-road speed of 100km/h in 7.9 seconds and reaches its top speed at 215 km/h or, with adaptive air suspension, 218 km/h. Its fuel consumption is impressively low, averaging 7.4 liters per 100 km, which is equivalent to CO2 emissions of 195 grams per kilometer. This is an improvement of 1.7 l/100 km or 19 percent.

The latest 3.0 TDI engine weighs much less than before: 198 kilograms, a reduction of 20 kg. A new chain-driven timing gear and a complex cylinder wall machining process have reduced internal friction. The new turbocharger is exceptionally responsive, making itself felt as rapid torque buildup. The common rail injection system has also undergone further development: it has a maximum operating pressure of 2,000 bar and can therefore inject fuel in an extremely precise spray pattern.

The crankcase and cylinder heads of the new 3.0 TDI have separate cooling water circuits connected together by valves. During the warm-up phase and when loads are not high, the coolant is not circulated in the engine block. This saves energy and raises the oil more quickly to its regular operating temperature. The new start-stop system switches off the engine when the Q7 comes to a standstill.

Audi also offers its customers a second version of the V6 TDI: the 3.0 TDI clean diesel. It already meets the exhaust emission limits laid down in the Euro 6 standard, which does not come into force until 2014, and the tough US regulations as well. Sensors in the combustion chambers, a common-rail fuel injection system with a delivery pressure of up to 2,000 bar and a high-performance exhaust gas recirculation system keep untreated exhaust emissions to a minimum. A DeNox catalytic converter in the exhaust system reduces the remaining oxides of nitrogen by means of an additive. The 3.0 TDI clean diesel also develops 176 kW (240 hp) and has an impressive 550 Nm of torque between 2,000 and 2,250 rpm. It takes the Q7 from a standstill up to 100 km/h in 8.1 seconds and gives it a top speed of 215 km/h , or 218 km/h with adaptive air suspension. Its average fuel consumption is 8.4 liters per 100 km.

The Q7 4.2 TDI has also had its fuel consumption drastically reduced – from 9.9 to 9.2 liters per 100 km – by installing a 2,000-bar fuel injection system and minimizing internal friction. Yet at the same time the V8 diesel, with its unchanged power output of 250 kW (340 hp), delivers more torque than before. It now supplies a vigorous 800 Nm between engine speeds of 1,750 and 2,750 rpm. The big TDI engine gives the Q7 performance figures worthy of a sports car. It accelerates from 0 to 100 km/h in 6.4 seconds and has a top speed of 242 km/h.

Audi has given all six- and eight-cylinder Q7 versions a new automatic transmission. The eight-speed tiptronic lowers fuel consumption by about five percent. It is based on the six-speed unit, but with another friction-clutch shift element added. Being able to shift between eight ratios keeps the jumps in engine speed low: the engine always runs close to its ideal operating point. All gear shifts are fast, flexible and take place extremely smoothly without delay.

To cut fuel consumption still further, the torque converter lockup clutch eliminates slip even at low engine speeds. Any engine vibration that could occur as a result is suppressed by the new damper in the torque converter until scarcely any trace can be detected.

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