Audi: no local release of clean diesel or flexfuel

The installation of the new 3.0-litre clean diesel V6 Audi first rolled out in the Q7 turns the A4 3.0 TDI quattro into a hot new competitor for BMW's 330d.

Cursory on-paper investigation shows the engine matches BMW's almost to the digit: an identical 180kW takes the A4 from 0-100km/h in an identical 6.2sec, via 500Nm of torque -- 20 less than the BMW. Audi claims average combined-cycle fuel consumption of 6.7 L/100km for the sedan, against BMW's 6.8.

Audi also claims the engine deploys 'the world's cleanest diesel technologies', including a new high-pressure common-rail injection system, with pressure sensors in the combustion chamber providing real-time data to an EMS capable of setting injection pressure at up to 2000 bars.

Toxic exhaust emissions are dealt with in several phases -- first through a manifold recirculation system, then through Audi's AdBlue-fuelled DeNOX filter and a catalytic converter.

AdBlue is a urea solution that, squirted into a passing stream of hot exhaust gases, decomposes into ammonia. In doing so breaks up nitrogen oxide molecules, turning them into nitrogen and water. Little enough of it is used that the car's supply doesn't need refilling.

The engine complies with the EU's Euro 6 standard, only set to become law in 2014.

Audi simultaneously announced a modified version its 2.0 TFSI A4 and A4 Avant to ready it for flexfuel, enabling it to run on ethanol blends up to E85.

To help offset the fuel consumption hike of up to 40 per cent stemming from bioethanol's lower energy density, much of the tweaking has been to make the most of its higher 110 RON octane rating.

Audi claims no noticeable differences in drivability or performance regardless of fuel blend. The flexfuel version generates the same 132kW power and 320Nm torque figures as the donor engine, and retains the company's 'valvelift' variable valve timing and auto start-stop systems.

Audi claims the engine is good for 9.0L/100 km running E85 in the A4 sedan, dropping to 6.4L/100 km running PULP. The figures are slightly higher for the Avant wagon.

The company points out that much of the fuel economy disadvantage incurred running E85 in Europe is absorbed by differences in tax -- it's much lower in ethanol than fossil fuels.

The sedan accelerates from zero to highway speed in 7.9sec on its way to a top speed of 236km/h; for the Avant these figures are 8.1sec and 228km/h. Both models transfer power to the road via the front wheels and a six-speed manual transmission.

The changes to the engine were minimal, with Audi having designed the engine from scratch with the flexfuel modification in mind. A sensor in the fuel line keeps the EMS informed of the ethanol to petrol ratio, allowing it to adjust injection and ignition to suit.

With fuel lines and seals already made of materials able to withstand ethanol's corrosive properties, the only other modifications entailed the use of new materials for the valve seat rings to account for ethanol's lack of lubricant qualities.

At this point the company is only releasing the car in Sweden, where E85 is relatively common.

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