Would you brew a cup of joe with a filter that spent time on a tailpipe? I wouldn’t either, but that’s the premise of a video on Volkswagen’s blog “TDI Truth & Dare.” A snowy-white coffee filter attached to a 2009 Touareg 2 TDI (turbocharged direct injection) diesel’s backside remains pristine, while a filter that’s connected to an old diesel model turns black. The message: Diesel isn’t dirty anymore.
Gasoline-electric hybrids -- and the soon-to-come plug-in hybrids -- still get most of the green ink, but clean diesels are vying for environmental street cred of their own. What skeptics may not know is that unlike the smoky, noisy diesels of the early ‘80s, today’s diesels are as clean as gasoline engines. The emissions rules that took effect two years ago forced manufacturers to retool their diesels to reduce smog-forming nitrogen oxides and soot. The new 2009 models meet California’s strict emissions standards and can be sold in all 50 states. In fact, diesels emit about 20% less carbon dioxide than gasoline engines do. And because diesel engines don’t have to be as large as gas engines to generate the same power, diesels are up to 40% more fuel-efficient.
The Price is Almost Right
To boost sales, diesels have to overcome. You’ll pay more for a diesel model than its gasoline-engine sibling, mostly because of the complex antipollution hardware and limited sales in the U.S. The premium ranges from $1,500 on Mercedes-Benz’s M-Class and R-Class diesels to $4,000 on the Audi Q7 TDI. The seven-seat Mercedes GL320 BlueTEC is a rarity – it’s $1,000 cheaper than the gas-engine model.
Until recently, diesel fuel cost more than gasoline. But in early June, the national average price for a gallon of diesel was almost 20 cents less than for regular gasoline. If you hold on to a diesel vehicle for five years (the typical ownership period), with diesel cheaper than gasoline, you’ll likely recoup the extra cost of the vehicle with savings at the fuel pump. Plus, tax credits are available for diesels; credits for the 2009 models range from $900 to $1,800.