Second-generation 3.0L V6 Diesel for Audi Q7 Cuts Fuel Consumption 19%; Lower-Emission Variant Meets Euro 6 or US Regs

.0 TDI engine weighs less than before: 198 kilograms (437 lbs), a reduction of 20 kg (44 lbs). 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 Euro 6 emissions limits as well as the US regulations. 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 550 N·m (405.66 lb-ft) of torque between 2,000 and 2,250 rpm. It takes the Q7 from a standstill up to 100 km/h (62 mph) in 8.1 seconds and gives it a top speed of 215 km/h (134 mph), or 218 km/h (135 mph) with adaptive air suspension. Its average fuel consumption is 8.4 liters per 100 km (28 mpg US).

3.0 TFSI. The new 3.0 TFSI gasoline engine replaces 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.

Two versions of the supercharged V6 are available. The basic version develops 200 kW (272 hp) and has a maximum torque of 400 N·m (295 lb-ft) over a broad engine-speed range from 2,250 to 4,750 rpm. It accelerates the Q7 in 7.9 seconds from a standing start to 100 km/h and gives it a top speed of 222 km/h (138 mph), or 225 km/h (140 mph) with adaptive air suspension.

The more powerful version of the 3.0 TFSI delivers 245 kW (333 hp) and a torque of 440 N·m (325 lb-ft) between 2,900 and 5,300 rpm. Acceleration from 0 to 100 km/h takes 6.9 seconds,; top speed is 243 km/h (151 mph), or 245 km/h (152 mph) with adaptive air suspension. In the EU fuel consumption test cycle, the engines consume 10.7 liters per 100 kilometers (22 mpg US). 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% respectively.

V8 4.2 TDI. The Q7 4.2 TDI has also had its fuel consumption reduced—from 9.9 (24 mpg US) to 9.2 liters per 100 km (26 mpg US)—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 N·m (590 lb-ft) between engine speeds of 1,750 and 2,750 rpm. The big TDI accelerates from 0 to 100 km/h in 6.4 seconds and has a top speed of 242 km/h (150 mph).

8-Speed Transmission. Audi has given all six- and eight-cylinder Q7 versions a new automatic transmission. The eight-speed tiptronic lowers fuel consumption by about 5%. 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.

At 7.25 to 1, the overall spread of ratios in the eight-speed tiptronic is unusually wide. In the lower ratios the Q7 accelerates powerfully; in the higher ratios it rolls along efficiently at low engine speeds.

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.

Drivers can choose between the D and S programs – or make their own gear shifts at the transmission selector lever or the optional steering-wheel paddles. In combination with the 3.0 TDI the new eight-speed tiptronic achieves an exceptionally high level of efficiency. Its oil cooler is heated after a cold start by hot coolant from the engine’s cooling system. An electric oil pump makes operation of the Q7’s start-stop system possible: it maintains oil pressure in the hydraulic circuit when the engine stops, and closes the clutch for restarting.

The eight-speed tiptronic transmission transfers engine power to the quattro permanent all-wheel drive train. This splits the power in a sporty manner, with 40% going to the front and 60% to the rear wheels, but in certain on- or off-road situations, the mechanical-action center differential can direct up to 65% of the power to the front or up to 85% to the rear.

The Audi Q7 V12 TDI quattro. Audi says that its Q7 V12 TDI quattro is the most powerful diesel SUV in the world. the 6-liter twelve-cylinder TDI engine develops 368 kW (500 hp) and delivers 1,000 N·m (738 lb-ft) of torque between 1,750 and 3,250 rpm to the six-speed tiptronic transmission. With a time of just 5.5 seconds from zero to 100 km/h and a governed top speed of 250 km/h (155 mph), the Audi Q7 V12 TDI has a fuel consumption 11.3 liters per 100 kilometers (21 mpg US).