World's cleanest

AUDI will commence production next year of what it claims are the cleanest diesel engines in the world, but question marks remain over whether Australia will get the benefit of them owing to our current and future diesel fuel standards.

Set to debut in the Audi A4 and Q7 models sold in the US and Europe from mid-2008, the new TDI engine will appear first as a 3.0-litre V6 that produces 176kW/500Nm and, with (unspecified) “outstanding fuel consumption figures and incomparably low emissions”, will meet highly stringent forthcoming standards such as Euro V (2009).

Nitrogen oxide emissions are claimed to have been reduced by up to 90 per cent.

However, Audi Australia confirmed to GoAuto this week that the engines require fuel with a sulphur content which is “ideally less than 10ppm (parts per million)”.

The current sulphur limit for diesel required by law is 50ppm, reducing to 10ppm in 2009. There is no timeframe for reducing this further.

“We are currently investigating the introduction of these engines for Australia, however the ultra-low emission TDI engines require very low sulphur content in fuels – at least less than 50ppm or ideally less than 10ppm,” said Audi Australia’s general manager of corporate communications Anna Burgdorf.

“It is highly likely that we will introduce the engines as soon as we are able. In the meantime, we are investigating any negative effects of 50ppm sulphur for these engines in Australia.”

Left: Current 3.0 TDI engine as used in A4, A6, A6 Allroad and Q7.

To improve on the current-generation direct-injection common-rail turbo-diesel engines, Audi said a “dramatic cut” in untreated engine emissions was achieved with a new piezoelectric common-rail system with an injection pressure of 2000 bar, along with “extremely efficient exhaust gas recirculation and optimised turbocharging”.

In a world first, combustion chamber sensors were also introduced to more precisely regulate the combustion process.

“Audi has been at the forefront of TDI introduction amongst the European brands in Australia – being the first to have a diesel engine in every major car line in Australia – and our intent is to continue to push forwards with this advanced technology, including low-emission engines and of course the use of diesel particulate filters,” Ms Burgdorf said.

The prospect of Audi Australia being able to introduce the German marque’s forthcoming new-generation direct-injection petrol engines looks gloomier than it does with diesel, considering local oil producers and their lobby group the Australian Institute of Petroleum have revealed to GoAuto that it would take until at least 2015 to reduce sulphur levels to 10ppm in premium unleaded.

There is currently no binding timeframe in Australia for reducing unleaded petrol to 10ppm, and the petroleum industry argues there is “no net benefit” to the Australian community in making such a move.

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