Volkswagen take on future engines

Diesel engines remain the most efficient powertrains for personal mobility for the time being, Volkswagen's head of research and development Dr Ulrich Hackenberg told a briefing on the eve of the Los Angeles show.

However, he admits that in future car makers will need to offer a balance of efficient petrols and diesels, hybrids, all-electric cars and fuel cells, and says the VW Group is 'well-prepared for all possible scenarios'.

The company chose smog-ridden LA to wheel out its latest Clean Diesel engine a 222bhp 3.0-litre V6, initially for the Touareg and Audi Q7. It will be re-christened Blue TDI for Europe.

VW claims it meets the conflicting demands of American and European governments. The Americans are more concerned about nitrous oxide emissions (NOx), which have been linked with all sorts of respiratory problems, while in Europe we are more focused on cutting fuel consumption and CO2.

However, VW engine chief Wolfgang Hatz says the new V6 reduces normal NOx emissions by 90% and therefore meets emissions standards in all American states while offering improved economy and CO2 output. They will also meet European emissions laws not due until 2014.

At Los Angeles the V6 Touareg sits on the stand alongside the Clean Diesel (Blue TDI) Jetta saloon and estate that went on sale in the US in the summer. These are powered by a re-engineered version of VW's 138bhp 2.0-litre TDI. It is so clean that Americans get a $1300 tax credit for choosing it.

The immediate future of both engines in the UK is uncertain, though: they would cost considerably more than current diesels, but the Government would give you nothing back in the way of tax breaks for having a green conscience.