Fret not. The diesel no longer needs to be dirty, smelly, black belching or clattering. That negative image is so 20th Century.

A new era has dawned for diesel. German car makers especially are striving to erase from American memory that outdated view of diesel's drawbacks. This at a time when diesel's strengths like longevity and superior fuel economy are particularly relevant.

The North American side of the Atlantic is far behind Europe in embracing the diesel. Some 40-45% of all continental cars are diesel while in the US market penetration is still in single digits. Fuel in Europe costs two to three times the peak US prices making the news lately. Economy is serious business in Europe and diesel at its worst is 25% more economical than gasoline at its best.

Besides being stars of the miles-per-gallon sweepstakes diesels are low maintenance (service this new M-B every 30,000 miles and its likely to be good for 300,000.) Since 1936 when Mercedes put the first diesel engine into an automobile some half-million diesel cars have found U.S. garage space. Half of them, MB says, are still on the road, still driven by dogged diesel partisans.

Those loyalists who just might crave a more sybaritic setting for their admiration of the diesel can now rejoice. After a five-year absence of the "D" in a sedan for the US it has returned in the 2005 Mercedes-Benz E320 CDI.

Outwardly the diesel E-Class is indistinguishable from the gasoline-powered version, but will cost about $1000 more (starting at just under $50,000.) That premium may well be paid back before the year is out through fewer stops for refills at the pump.

The "CDI" designation in this E-Class encodes breakthrough innovations in diesel technology. The letters stand for "common-rail direct injection" which in this 3.2 in-line-six serves to transport the inherent efficiency of diesels into even greater efficiency. The fuel metering system manages to deliver to the engine (in concert with the Variable Nozzle Turbine or VNT turbocharger) the optimum amount of fuel needed for the task of the moment and is laboratory precise.

Thus the new quiet, the new smokelessness, the smart takeoff from a stop and the mileage rating upwards of 30 mpg in mixed city and highway.

Comparing the diesel E to the gasoline-powered E: both have a five-speed automatic transmission. The diesel produces 201 HP, the gas engine 240. But the diesel delivers 369 foot-pounds of torque in the 1800-2600 RPM segment of the tachometer. The higher-horsepower gas version is rated at 232 ft-lb of torque at a higher point on the tach.

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