Diesel owners are a fanatical lot. They’ll buy, they’ll drive for decades, and when their diesel finally gives up the ghost, they’ll buy another one. And don’t get us started on the folks who fill the tank with French fry grease and make fellow rush-hour motorists hunger for a biggie-size container of cholesterol. Appealing to diesel loyalists and newcomers alike, the 2007 Mercedes-Benz E320 Bluetec debuted at the 2006 North American International Auto Show in Detroit.

This is, however, a new kind of diesel. With the advent of common-rail direct fuel injection and four-valve cylinder heads in 1997, much of the clatter and smoke of older diesels was replaced with cleaner exhaust, more refined operation, and boosted power and torque ratings. Despite this upgrade, however, diesel engines have been unable to pass the most recent emissions regulations in the Northeastern U.S. and California. Bluetec technology will allow diesel-powered Mercedes-Benz products to be sold in those regions starting in the fall of 2006, and will meet the most stringest regulations worldwide through the end of the decade.

Bluetec arrives first under the hood of the 2007 Mercedes E-Class, but will be added to the company’s three SUVs shortly thereafter. The production version of the 2007 Mercedes-Benz E320 Bluetec blends one of the nicest luxury sedans on the market with a 35-mpg highway fuel economy rating and the torque of a V8 engine. But the best news is that when the E320 Bluetec hits the road, it will do so in California and New England, regions of the U.S. that are currently verboten to turbodiesel engines in passenger cars.

Editor’s Note: If you want to know how Bluetec technology makes a turbodiesel engine clean, read on. Otherwise, you’ll get bored, so skip to the end.

Diesel fuel sold in the United States contains large amounts of sulfur, and this sulfur content, among other factors, is what causes a diesel engine to run dirty with nitrous-oxide emissions. With Bluetec technology, emissions are reduced through the use of an oxidizing catalytic converter, a particulate filter, and what Mercedes calls a DeNOx nitrogen-oxide reducing system. DeNOx is the key here, a storage catalytic converter designed to treat engine exhaust gases before they are emitted from the tailpipe, and it reduces nitrogen-oxides by up to 80 percent. A reducing agent called AdBlue is injected into the gases contained in the storage catalytic converter, releasing ammonia which converts the nitrogen oxides into harmless nitrogen. The separate tank that stores the AdBlue is refilled whenever the car returns to the dealer for service.

To work properly, Bluetec technology requires the use of low-sulfur diesel fuel, defined as that with a sulfur content below 15 parts per million. This type of fuel will be available in the U.S. starting in the fall of 2006, at the same time the E320 Bluetec goes on sale, but may not be widely available. Over time, however, the fuel will become the standard in North America, and DaimlerChrysler will be ready to capitalize on this with a fleet of Bluetec-equipped cars and SUVs wearing Chrysler, Dodge, Jeep, and Mercedes-Benz nameplates.

Designed to meet upcoming 2009 emissions regulations and beyond, Bluetec is no temporary fix. In Europe, where half of all new vehicle buyers choose a diesel model, more than 10,000 heavy-duty trucks already use Bluetec. Plus, Mercedes-Benz plans to connect Bluetec diesels to hybrid drive systems to create even cleaner, greener, and more efficient vehicles in the future. Clearly, DaimlerChrysler thinks that diesel will power tomorrow’s cars in greater numbers, and Bluetec will be the instrument it uses to ensure success.

Photo courtesy of Mercedes-Benz