Crossing the Blues

Monday, January 14, 2008

New Audi A6 Avant - In Depth


Page 1 - Design
Page 2 - Engines and transmissions
Page 3 - Engines and transmissions (cont.)
Page 4 - The chassis
Page 5 - The chassis (cont.)
Page 6 - The body
Page 7 - Comfort and communication electronics
Page 8 - Comfort and communication electronics (cont.)
Page 9 - Standard equipment
Page 10 - Optional equipment


Engines and transmissions

The Audi A6 Avant will initially be available with a choice of no fewer than six engines installed longitudinally – three petrol and three TDI power units. All these engines share a level of power and torque that is outstanding in this segment of the market:

  • 4.2 V8 developing 246 kW (335 bhp), 420 Newton-metres
  • 3.2 V6 FSI developing 188 kW (255 bhp), 330 Newton-metres
  • 2.4 V6 developing 130 kW (177 bhp), 230 Newton-metres
  • 3.0 V6 TDI developing 165 kW (225 bhp), 450 Newton-metres
  • 2.7 V6 TDI developing 132 kW (180 bhp), 380 Newton-metres
  • 2.0 TDI developing 103 kW (140 bhp), 320 Newton-metres (mid-2005)
All engines comply with the limits of the EU4 emission standard.

The six and eight-cylinder power units come from Audi's new V-engine family. Their highlights in design and construction are the 90° cylinder angle and a distance of 90 millimetres between the cylinders, compact dimensions, maintenance-free camshaft drive via a chain and low-friction roller-arm valve drive.

The petrol engines

4.2 V8

The powerful 4.2 V8 with chain drive made an outstanding debut in the Audi S4 at the end of 2002. Now it has been retuned for the Audi A6 and A6 Avant, offering powerful torque up to nominal engine speed plus an agile response and superior fuel economy all in one – these are the characteristics of this new engine.

This engine is notable not only for its assertive output of 246 kW (335 bhp) at 6,600 rpm and a peak torque of 420 Nm at 3,500 rpm. The resulting road performance is also impressive, even in this demanding sector.

The new A6 4.2 quattro accelerates from a standstill to 100 km/h in a mere 6.2 seconds, continuing smoothly all the way to the car's electronically limited top speed of 250 km/h. Its overall fuel consumption is just 11.7 litres of Super Plus per 100 kilometres.

The unbeatably short design of this engine is also impressive, especially in view of the fact that its compact dimensions enable it to fit in the engine compartment without the front end having to be increased in size, as was the case on the previous model.

To make this compactness possible, the Audi engine developers have installed a chain drive for camshafts and ancillaries on the engine output side. This made it possible to reduce the length by no less than 52 millimetres compared with the previous unit which had the same displacement.

An additional advantage is that, weighing a mere 195 kg, the entire V8 power unit is extremely light. On the road, this means significant benefits in terms of both balance and driving dynamics.

The V8 power unit breathes through a two-stage variable intake manifold made of magnesium. The length of the ram pipe in the torque position is 705 mm, reducing to a length of just 322 mm in the power position. Engine management is the task of the advanced Bosch Motronic ME 7.1.1. This system provides the option of activating the starter electronically, thus enabling the driver to start the engine keylessly, simply by pressing a button (advanced key).

Exhaust emissions are cleaned by two multi-stage catalytic converters which are positioned close to the engine so that they heat up quickly. Thanks to the efficiency of this system, the new Audi A6 4.2 easily outperforms the EU4 emission limits, even with the standard features of quattro drive and tiptronic transmission.

3.2 V6 FSI

The 3.2 V6 FSI, which made its debut in the A6 saloon, boasts all the features of an ultramodern petrol engine: FSI petrol direct injection with demand-controlled fuel supply, four valves per cylinder, a variable intake manifold and continuous camshaft adjustment on both the intake and exhaust sides.

This V6 engine delivers its maximum output of 188 kW (255 bhp) at 6,500 rpm; its peak torque of 330 Nm is available at just 3,250 rpm. The A6 3.2 FSI with 6-speed manual gearbox and front-wheel drive accelerates to 100 km/h in 7.1 seconds, while its top speed is electronically limited to 250 km/h (this also applies to the version with quattro permanent four-wheel drive and 6-speed tiptronic transmission).

More than 90 percent of the engine's maximum torque is available across a wide speed range from 2,400 to 5,500 rpm – a unique characteristic for a naturally aspirated V6. As far as the driver is concerned this means a dynamic and forceful response to every movement of the accelerator pedal plus a broad usable speed range up to 7,200 rpm, hefty torque and excellent fuel efficiency: an average consumption of 9.9 litres of Super grade fuel per 100 km is the best evidence of this engine’s efficiency and the special abilities of FSI technology.

FSI engines develop more power and dynamism than conventional units with indirect manifold injection – and they do so with a very high standard of fuel economy. Boosting efficiency in this way, Audi is adding a new dimension to the operating efficiency of standard petrol engines, once again demonstrating the "Vorsprung durch Technik" that is so typical of the brand.

In June 2001, FSI direct petrol injection system confirmed its unique potential in what must be the most challenging endurance test in the world: a power unit with FSI direct injection drove the Audi R8 to victory in the Le Mans 24 Hours.

So how does FSI technology differ from a conventional engine? The term "petrol direct injection" makes the central feature clear: in contrast to indirect injection where fuel is injected into the inlet manifold, the fuel is injected directly into the combustion chamber.

A common rail high-pressure injection system with a newly developed, demand-controlled single-piston high-pressure pump ensures exactly the right supply of fuel, delivering precisely the volume required for building up operating pressure to between 30 and 100 bar.

In the intake tract, also comprising the two-stage variable intake manifold, moving charge movement flaps swirl the induced air around as necessary. Together with the optimum geometry of the combustion chambers and the supremely accurate metering of injected fuel down to the last millisecond, this allows a significant increase in compression: while conventional production engines generally have a compression ratio of not more than 10.5:1, the compression ratio of the Audi 3.2 FSI power unit is 12.5:1 – a record for production cars and the essential prerequisite for the new engine's high standard of efficiency.

New base engine

New in its design, the 3.2-litre V6 has been developed with the specific goal of maximum space efficiency: measuring only 360 mm in length and 430 mm in width, and weighing a mere 169.5 kg thanks to the use of aluminium, the engine offers significant benefits in terms of driving dynamics.

As on Audi’s other new V-configuration engines in general, the cylinders are arranged at an angle of 90o and the distance between cylinders is 90 millimetres. Cylinder bore of 84.5 mm and cylinder lift of 92.8 mm add up to an overall engine capacity of 3,123 cc.

The four-valve cylinder head with a side opening for the injection valve is another special feature designed specifically for this 3.2-litre power unit. Both the inlet and exhaust camshafts come with variable adjustment to ensure optimum results, in terms of both maximum output and an extremely broad peak-torque range.

The camshafts, oil pump and balancing shaft are all driven by four-piece chain drive of the same type as in the 4.2-litre eight-cylinder unit.

Emissions control in the 3.2 FSI is optimised by two ceramic catalytic converters positioned close to the engine. As a result, this high-performance power unit easily undercuts the EU4 emissions standard.

Fine-tuning of the exhaust system offers the driver yet another bonus: the distinctly sporty but never intrusive sound of a genuine six-cylinder unit, making the qualities of the engine a truly sensory experience.

The Audi A6 Avant 3.2 FSI with front-wheel drive is available with a manual 6-speed gearbox or multitronic. The permanent quattro four-wheel-drive model comes with a choice of either a manual 6-speed gearbox or 6-speed tiptronic, whatever the customer prefers.

2.4 V6

Another premiere for the new generation of the A6 Avant: the 2.4 V6 is the smaller version of the 3.2-litre power unit with a smaller displacement and featuring intake manifold fuel injection. In all, the two engines differ through just 33 components – apart from the combustion process as such, these include the intake tract and the two-stage variable intake manifold.

Considering this close resemblance, it is no surprise that the smaller of the two six-cylinder units has all the basic virtues of the 3.2 FSI: sports character combined with exemplary smoothness and refinement, plus a high degree of all-round efficiency.

As on the 3.2-litre version, the engine's silky-smooth, vibration-free running results not least from the balance shaft module which is able to eliminate oscillations extremely efficiently.

The cylinder stroke of 77.4 mm and the bore of 81 mm combine to provide an overall engine displacement of 2393 cc. From this capacity the new V6 engine delivers a maximum output of 130 kW (177 bhp) at 6,000 rpm and a maximum torque of 230 Nm between 3,000 and 5,000 rpm.

This is an excellent basis for an extremely sporty performance: this version of the A6 Avant accelerates to 100 km/h in 9.2 seconds and on to a top speed of 226 km/h. The combined-cycle fuel consumption is 9.9 litres of Super fuel per 100 kilometres. And in common with all other A6 engines, its emissions are below the limits of the EU4 standard.

The front-wheel-drive Audi A6 Avant 2.4 will be available at launch with either a 6-speed manual gearbox or with the continuously variable multitronic transmission. The A6 Avant 2.4 is also offered as a quattro model with 6-speed manual gearbox.



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