Hailing the Diesel’s Return
2005 Mercedes-Benz E320 CDI


Mercedes-Benz, the company that invented the diesel car, is trying to reinvent the market for diesel automobiles in the United States.

The strategy is to start small, with the introduction this spring of the 2005 Mercedes-Benz E320 CDI.

The car has an advanced common-rail, direct-injection (CDI) engine that runs quietly, burns cleanly and produces enough power to move the mid-size luxury sedan from 0 to 60 miles per hour in 6.8 seconds.

Yet, the E320 CDI gets better mileage than an automatic compact Toyota Echo economy sedan, which weighs 1,730 pounds less than the Mercedes-Benz car.

In fact, when driven at legal speeds with the air conditioner and entertainment systems turned off, the E320 CDI gets real-world mileage comparable to that of the much-ballyhooed Toyota Prius gas-electric hybrid.

I know this to be true because I joined journalists from around the nation here last week in an extensive highway-and-city mileage test of the E320 CDI. My team finished third with an average highway-city mileage of 40.7 miles per gallon. The top finishers, led by automotive writers Brian Armstead and Frank Washington, averaged 45 mpg. (Hints: The Armstead-Washington team used no electrical appliances, not even turn signals. They drove at steady, moderate speeds, which means they used brakes as little as possible; and they coasted in neutral gear at every conceivable opportunity.)

By comparison, my family’s gasoline-fueled four-cylinder Toyota Echo generally gets 34 miles per gallon in highway-city driving. The best real-world mileage I’ve ever gotten out of many drives in past and current versions of the Toyota Prius is 46 mpg, and that was mostly highway running.

The E320 CDI’s collective virtues should be enough to bring diesel-skeptical Americans into the diesel camp. But Mercedes-Benz executives aren’t taking any chances. They view the U.S. market as being hostile to automotive diesel technology. So they are proceeding cautiously with initial plans to sell 3,000 E20 CDI models annually — mostly to former and current owners of older Mercedes-Benz diesel cars.

Those people are true believers. They were upset when Mercedes-Benz stopped selling the E300 Turbodiesel in the United States at the end of 1999. That sales disruption stemmed from a redesign of the company’s E-Class cars, which now include sedans and station wagons available with rear-wheel drive, or with Mercedes-Benz’s patented “4Matic” all-wheel-drive system.

The company redesigned the E-Class body in model year 2000, giving it a lower hood line that was at odds, in terms of proper fit, with the big diesel engine.

But in addition to being cleaner, quieter and more powerful (201 peak horsepower for the E320 CDI compared with 174 hp for the Turbodiesel), the new 3.2-liter, inline si x-cylinder engine is also more compact.

Key elements in its design include an electronically operated direct fuel-injection system, a common-rail fuel loop, an engine-driven fuel pump and a Variable Nozzle Turbine (VNT). Those components work together to ensure consistent fuel pressure, a more thorough dispersion of fuel in the engine’s combustion chambers and a cleaner, more powerful burn of the air-fuel mixture.

The result is a diesel engine that pollutes less, runs faster and practically eliminates any reasonable opposition to the reintroduction of high-caliber diesel passenger cars in the United States.

At least, that is what Mercedes-Benz executives are hoping.

They want to appeal to true believers by giving them a car that justifies their continued faith. They hope that E320 CDI buyers will be so thrilled by the new car that they will go forth and spread the New Diesel Gospel according to Mercedes-Benz. If things go right, there will b lots of converts. Amen.

Nuts & Bolts

Downside: Although diesel engines generally get up to 30 percent better fuel economy and produce 20 to 30 percent fewer carbon monoxide (CO) and carbon dioxide (CO 2 ) emissions than comparable gasoline models, diesels generate more parts per million of oxides of nitrogen (NOx) and particle pollutants. As a result, sales of the 2005 E320 CDI will be limited to 45 states where the car meets air pollution standards. Mercedes-Benz executives hope to extend sales to all 50 states by 2006.

Ride, acceleration and handling: Excellent in all three categories. The car has unbelievable torque. And despite its weight of 3,835 pounds, it handles with the aplomb of a lighter sports car along the winding, twisting roads of the Texas hill country.

Head-turning quotient: It’s a Mercedes-Benz E-Class. People look at the car and assume that you’re rich. Wealth has its own appeal.

Engine/transmission: The E320 CDI is equipped with a 3.2-liter turbocharged in-line six-cylinder, common-rail, direct-injection diesel engine that develops 201 horsepower at 4,200 revolutions per minute and 369 foot-pounds of torque between 1,800 and 2,600 rpm. The engine is linked to an electronically controlled five-speed automatic transmission.

Body/style layout: Front-engine, rear-wheel-drive luxury sedan.

Capacities: The car has comfortable seating for five people. Luggage capacity is 15.9 cubic feet. The fuel tank holds 21.1 gallons of required low-sulfur diesel fuel.

Mileage: Our team averaged 40.7 miles per gallon in the E320 CDI mileage contest in San Antonio. We finished third. Our first-place rivals finished with a 45-mpg average using extreme fuel-conservation measures.

Safety: Everything you would expect in a Mercedes-Benz car, including eight air bags — two in front, four side bags and two curtain window (head) bags.

Historical note: The 1936 Mercedes-Benz 260D was the world’s first production diesel passenger car.

Price: The 2005 Mercedes-Benz E320 CDI goes on sale this spring. Prices have not been announced at this writing. Initial estimates are in the range of $40,000 to $50,000.

Purse-strings note: If you can find a better diesel car, buy it. But my hunch is that, in America, you’ll have to wait at least two more years before the appearance of a worthy rival.

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