Volkswagen's newest Jetta TDI has just passed the world's most stringent diesel emissions test. As if there had been any doubt, the days of smoky diesels are now officially over. The Jetta TDI, expected to launch in 2008, perhaps as a 2009 model, conforms to the California "Tier 2 / Bin 5" emissions standard. This standard, also adopted by Massachusetts, New York, Vermont, and Maine, is considered to be the world's strictest, and limits emissions of oxides of Nitrogen to 70 mg per mile. The Jetta's 2.0-liter common-rail turbo diesel engine meets the standard by using a NOx reservoir that, like the particle filter, is automatically cleaned out by the engine management system while driving. Larger diesel cars, like the Passat, won't use the NOx reservoir. Instead, they will use Selective Catalytic Reduction (SCR) to lower emissions. The SCR system uses a catalytic converter that uses a fluid to convert the oxides of nitrogen into nitrogen and water. The problem with these systems is that the fluid will have to be refilled periodically. Volkswagen plans to incorporate a tank large enough to last through two service intervals. The members of the BlueTec consortium (VW, Audi, and Daimlerchrysler) cleverly call the fluid AdBlue to detract from the fact that it consists of 32.5% urea. Yeah, urine. AdBlue is, however, non-toxic, odorless, and completely biodegradeable, so this won't be the case of replacing diesel smells with NY subway smells. BlueTec was formed as a joint initiative to help bring diesel passenger cars to the US, and it couldn't have happened soon enough for our tastes. We've said it time and time again - Diesel engines suit the driving style of Americans almost perfectly and offer tremendous real-world fuel economy gains. They're quiet, smooth, seriously fast, and now seriously clean. It's time to wake up, America, and embrace that lovely diesel stink. Um, yeah, except that doesn't exist anymore.
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