2009 Jetta SportWagen, clean diesel

New diesels will get better mileage and have cleaner emissions than your average car. Pictured above: 2009 Jetta SportWagen 2L TDI Clean Diesel.

Later this year (see the timeline below), we will finally begin to see an influx of new model diesels in the United States. While diesels make up 50% of the market share of vehicles in Europe, they’re still trying to shrug off the stigma of being dirty, noisy beasts here in the US. So what changed?

What are “clean” diesels?

In 2006, the EPA required the introduction of Ultra Low Sulfur Diesel (ULSD), which removed a major polluting component of diesel fuel. Since sulfur would damage advanced emissions control systems, ULSD paved the way for better emissions control technology.

As early as August, we will start to see a new era of diesels that employ new technology to meet the strictest emissions standards in the world—BIN5/LEV II—which are enforced by 5 US states: California, Massachusetts, Maine, New York, and Vermont. BIN5/LEV II standards severely cap nitrogen oxide (NOx) emissions (0.05 g/mile), one of the two tailpipe pollutants that have given diesels a bad rap (that and particulate matter).

Newer filters in these emissions systems trap particulate matter, while each model uses its own method to process NOx. Several models, including those from BMW, Mercedes, and Audi, will require the maintenance of a six- to eight-gallon tank of urea. The ammonia-rich solution (for example: Mercedes BlueTEC) is injected into exhaust to neutralize smog-forming nitrogen oxides. Since the urea tanks only require replenishing every 12,000 miles or so, inconvenience seems minimal, and some models, like Honda and VW diesels, meet emissions requirements without them.

While you might expect most of these diesels to get exceptional mileage, some of them do surprisingly poor. For example, the Mercedes and Audi models only get around 18/25 MPG (making this a good reason to continue to avoid SUVs). I know that the new emissions technology is supposed to negatively affect mileage, but 25 MPG is unimpressive, considering that VW’s Jetta BlueTDI got a road tested 60 MPG.

While the high price of diesel fuel is eating into some of the economic advantage of buying a new diesel vehicle, the difference is offset by mileage gains of 25 to 40% over comparable gas models. You might not see too much difference in sticker prices, either. Some models could cost $1,500 to $3,500 more for this new emissions control technology, but VW says its Jetta SportWagens could cost $2,000 less. Also be on the lookout for Federal tax credits that could be as large as $3,400 per vehicle.

When can we expect to see clean diesels in the US? Here’s the timeline:

2009 Jetta BlueTDI, Clean Diesel

1. Volkswagen

  • When: August 2008
  • Models: 2009 Jetta BlueTDI sedans and SportWagens
  • Engine: 2-liter turbodiesel in-line 4
  • Est. Mileage: 29/40 m.p.g. Sedan road tested at 60 MPG.
  • Est. Base Price: $22,000 to $25,000

Mercedes ML320, clean diesel

2. Mercedes

BMW 335D, Clean Diesel

3. BMW

Audi Q7, clean diesel

4. Audi

When: January 2009

Honda Accord Clean Diesel

5. Honda (yes it’s true)

  • When: 2009
  • Models: Acura TSX sedan, other models could follow
  • Engine: 2.2-liter i-DTEC
  • Est. Mileage: 34/53 MPG
  • Est. Base Price: ?

Jeep Grand Cherokee

6. Jeep

  • When: 2009
  • Models: Jeep Grand Cherokee
  • 7. General Motors/Ford/Dodge

    2009 Nissan Maxima Sedan

    8. Nissan

    Subaru Diesel

    9. Subaru

    • When: 2010
    • Models: Legacy sedan or Outback wagon
    • Engine: 2-liter turbodiesel flat 4
    • Est. Mileage: 33/47 m.p.g. (Outback)
    • Est. Base Price: $28,000 (Outback)

    Header Photo Credit: VW

    For more, see: Diesel Engines Clean Up for an Encore (New York Times)

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