New diesels deserve a second look
In the short term, one of the most expedient things we could do to reduce carbon dioxide emissions from new cars and trucks is what the Europeans have already done: switch to diesel engines.
Approximately half of all new light-duty vehicles purchased in the EU are diesel powered. And that figure applies across the whole range of vehicle segments.That success is driven primarily by economic considerations: diesel fuel is typically much cheaper than gasoline, thanks to favourable tax structures, and diesel engines inherently consume 25 per cent to 30 per cent less fuel than corresponding gasoline engines.
Combine the two and consumers may save close to 50 per cent in fuel costs. That is a serious incentive in lands where gasoline typically costs twice what it does here.
Even that financial motivation might not be enough if the engines did not perform well. But they do – better than gasoline engines in many respects.
Today's high-tech diesels are almost as quiet as gasoline engines, and much more responsive in the relatively low engine-speed ranges where most drivers operate, which makes them almost ideally suited for the North American driving environment.
Jeep and Mercedes-Benz are currently offering diesels here and several other automakers, including Acura, Audi, BMW and Volkswagen, are expected to introduce or reintroduce them soon.
They have been absent recently because, as clean as they already are in Europe, new emissions regulations currently in effect in North America are dramatically tougher to meet.
And they are getting tougher still. By 2010, diesels across the continent will have to be as clean as gasoline engines in every respect.
To meet those regulations, most manufacturers will adopt sophisticated exhaust after-treatment systems that include catalytic converters, a particulate trap and a urea injection system in the exhaust.
The latter is the extra step needed to get from where we are now to where we need to be. A urea solution called AdBlue is ahead of the final catalyst, whose purpose is neutralizing smog-forming oxides of nitrogen (NOx).
I recently drove an Audi A5, equipped with the same 3.0-litre V6 diesel that will be used here in the Q7 and the urea injection system, from Niagara to Toronto, and can confirm that it performs admirably. In fact, with its instant response to just a squeeze of the accelerator at highway cruising speed, I prefer it to the gasoline-engined A5, which is itself a highly desirable car.
Given all its advantages, the acceptance of today's diesels by Canadian consumers would seem to be a sure thing – but for the cost.
Diesels inherently cost more because they must be mechanically more robust – they operate at much higher compression and ignition pressures – and because they require highly sophisticated fuel-delivery systems that operate at pressures as high as 2000 bars (29,000 p.s.i.).
Audi Canada's president, Diego Ramos, is cautious about committing to diesel vehicles for Canada. He wants to see how the Q7 diesel does in the market before confirming the availability of other models here.
If our politicians are really serious about supporting alternative technologies to reduce greenhouse gases, they could help things along by reconsidering the tax structure on diesel fuels, thus helping to offset some of that cost premium.
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