Mercedes-Benz diesel meets emission standards

It’s not surprising to see diesel priced at $5.50 per gallon in some sections of the country. With the current price of diesel fuel higher than gasoline, you’d laugh if I said your next car might be diesel-powered.

New diesel technology, however, can beat the price of gasoline by the better mileage it gets — by as much as up to 33 percent miles per gallon more.

Despite high diesel prices, Mercedes-Benz is optimistic that they’re setting the stage for a diesel revival with the launching of a trio of Sport Utility Vehicles equipped with diesel engines that are so emissions clean they can be sold in all 50 states.

California, and seven other states that use the same emissions standards, have banned diesel light-duty vehicles for several years. However, the introduction of low-sulfur diesel fuel (the cleanest burning diesels in history) has set the stage for the new diesel age.

The 2009 Mercedes BlueTEC diesel SUVs have remarkably clean emissions thanks to a new technology that uses AdBlue, a urea solution that’s sprayed directly into the diesel exhaust. This turns NOx — a major element that forms smog — into benign nitrogen and water vapor. An advanced catalytic converter and particulate filter will clean other emissions and trap soot particles so well that the exhaust, too, is very clean.

The 2009 ML, GL and R 320 with the BlueTEC engine, which go on sale this fall, are the first oil burners drivers in all 50 states can buy. Thomas Ruhl, director of the Mercedes BlueTEC project, is confident that Americans are ready for diesels again.

One thing that Mercedes has done is hold the premium for the diesel engine to about $1,000. Ruhl says Mercedes can hold the premium to such a low price because it builds high volumes of diesels for its other global markets.

Additionally, Mercedes has cautiously set the stage in recent years for a diesel revival, introducing the E320 BlueTEC in 2006 that now accounts for 7 percent of E-Class sales, even though it was not available in California and other big markets, including New York.

“We have the potential to build even further on this success,” Ruhl says.

Diesels are inherently more expensive because they cost more to make.

They require expensive high-pressure fuel injectors, as well as engine materials that are stiffer and heavier to tolerate the high pressures generated in diesel engines. Sensors used in diesel exhaust systems are also more expensive to make.

The 3.0-liter V-6 BlueTEC diesel generates 210 horsepower and 398 pounds-feet of torque. It is the cleanest diesel ever offered in the U.S.

Four engineering innovations were used to clean the diesel exhaust, including an oxidizing catalytic converter, a particulate filter that cuts soot by 98 percent and the AdBlue urea solution that is injected into the exhaust stream to turn 80 percent of NOx into emissions into harmless gases.

Cleaning the exhaust doesn’t bite into fuel economy because the diesel gives 20 to 33 percent greater miles per gallon than a comparable gas engine.

Ruhl claims this results in a six-cylinder engine that provides four-cylinder fuel economy, but with V-8 power and torque.

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