50 MPG+ And Cleaner Than Gasoline: Where Are The ‘Clean-Diesels’?
Since last year, many of us have been eagerly awaiting the introduction of ‘clean-diesels’: the 2008-2009 models touted as having superior mileage and cleaner emissions than comparable gas models.
So where are they? Strangely, promised 2008 models didn’t materialize, and I had trouble finding more on the story. As far as I can tell, we’ll just have to look forward to next summer’s release of the 2009 VW Jetta TDI. The new Jetta gets similar mileage to older models, 50 mpg ( though VW engineers claim 30% better mileage under real world conditions). More importantly though, it’s the first diesel to meet the world’s toughest emissions standards, California’s Tier II, bin 5, earning it clean-diesel status. If you noticed the recent lack of diesel vehicles for sale (especially in CA), it was the direct result of reengineering emissions systems:
Although it won’t be wearing the “BlueTec” badge, the Jetta will be using emission-cleansing technologies developed under the cooperative formed by Audi, Mercedes-Benz and Volkswagen to make it 50-state legal. Most BlueTec vehicles control NOx emissions—one of the biggest environmental hurdles facing diesels, along with particulate matter—by injecting a urea-based solution into the exhaust system upstream from the catalytic converter, where NOx is then converted into nitrogen and water. The Jetta will instead use a NOx-storage catalyst, which is basically a reservoir that temporarily holds the noxious emissions, like a particulate filter, until they can be burned off during one of the engine cycles.
