Our local paper published this recent article/review on MBZ's new diesels. My hope is that this will bring an influx of used diesels to the market as owners upgrade. It will be a buyers market.
Mercedes-Benz brings back its diesel cars
Saturday, May 22, 2004
By BOB HILL
-- DRIVETIME EDITOR
Even for auto writers, who tend to love high-performance and luxury cars, the high cost of gasoline is having an adverse effect. Test-drives of economy cars are more welcome as they promise a week's respite from the nightmare at the pumps.
But the recent arrival of a 3,835-pound Mercedes-Benz luxury sedan, which can go 0-60 mph in 6.8 seconds, was no cause for mixed emotions because this Mercedes carries a mileage rating of 27 mpg city and 37 mpg highway.
It's the new E320 CDI diesel-powered Mercedes, and if you already have an opinion about diesel engines this car will change it. The car is quiet, there is no diesel smell, and the acceleration is better than the comparable gas-powered E320, which gets gas mileage that is 40 percent worse.
With its mileage and 21-gallon fuel tank, the 2005 E320 CDI -- available at dealers now -- should take you from Portland to San Francisco on one tank. For that extra mileage, you pay $1,000 more for the CDI than the gas-powered E320.
Of course, people who pay more than $45,000 for a car may not worry much about the price of either gasoline or diesel. That is probably why Mercedes emphasizes performance and luxury more than mileage in its marketing and why it only expects to sell 3,000 CDIs a year. (The low sales projection is also partly because Mercedes cannot sell the car in California, Maine, Vermont, Massachusetts and New York because it can't meet those states' air pollution regulations.)
Mercedes sold the first production diesel car in the world in 1936 and has a long history in diesel-powered car sales. In the 1980s, around 75 percent of the cars it sold in the United States were diesels -- many of which are still on the road.
Diesel cars lost much of their popularity in the United States in the 1990s for a variety of reasons, including noise, smell, lack of acceleration and a paucity of diesel refueling stations. Mercedes last sold a diesel car here in 1999. But in Europe, because of the extremely high cost of fuel in many countries, about 40 percent of the cars sold are diesels.
Diesels are looming larger here. Volkswagen has sold diesel cars in this country for many years and will offer a diesel in its Touareg SUV this year. Jeep is bringing out a diesel Liberty SUV this year. The U.S. government also has regulations in place to drastically cut the sulfur content of diesel by 2007, which will make diesels more viable from an environmental standpoint. This cleaner diesel is already in use in Europe.
The new technology controlling engine fuel intake is what has really changed diesels in the last few years. In late 1997, Mercedes-Benz introduced the world's first diesel engine with CDI, which stands for "common-rail direct injection." The first truly electronic fuel injection system for diesels, the CDI system provides more precise control of injection quantity, simultaneously making more power, lower exhaust emissions and quieter operation.
The power ratings of the E320 CDI give an indication of this power: The car's turbocharged, 3.2-liter, 24-valve inline 6-cylinder is rated at 201 horsepower and 369 ft-lbs. of torque -- a torque rating typically found on a big V-8 gas engine. Unlike previous diesels, power is available quickly with this engine -- enough acceleration to push you back in your seat.
(Editor's Note: Those not interested in the intricacies of the Mercedes diesel's operation might want to skip the next three paragraphs.)
Although many non-turbo diesels have compression ratios of more than 20:1, Mercedes engineers found that in conjunction with the CDI's exhaust-driven turbocharger, the engine is most efficient with a compression ratio of 18:1. (The compression ratio of diesel engines is much higher than gas engines because diesels don't use spark plugs; they rely on the heat generated from the extreme compression of the air-fuel mixture for ignition.)
In the CDI system, a common rail, or line, delivers fuel to each cylinder simultaneously and under incredibly high pressure -- almost 23,000 pounds per square inch. The fuel goes to six electronic injector valves, each with the latest seven-hole nozzles that disperse the fuel evenly in an extra-fine mist.
Mercedes engineers also found that by taking advantage of the speed and precision of CDI, they could do "pilot injection" -- ignite small quantities of fuel twice in rapid succession a few milliseconds before the main combustion in each cylinder. This makes combustion temperature and pressure increases more gradual, softening the typical diesel noise and cutting oxides of nitrogen, which are the main pollutants from diesel.
Sitting inside the rear-wheel-drive E320 CDI, there is no sound that would indicate the car has a diesel engine. If you are standing by the car when it first starts up you can hear some faint diesel clatter, but it soon disappears as the engine warms up.
The only external indication that the E320 is diesel-powered is the "CDI" logo on the trunk. Otherwise, the car looks the same inside and out as any other E-Class sedan.
The CDI does weigh about 200 pounds more than the gas-powered E-Class, but this doesn't seem to affect ride or handling. The ride has a European firmness to it without being unpleasant. The handling is precise and stable with a little sportiness. Braking is excellent.
The car comes with all the other standard and optional luxury amenities one would expect in a $50,000 Mercedes -- fine leather and walnut wood, comfortable power seats, an excellent stereo, electronic trunk closing, rain-sensing wipers and a navigation system. Safety equipment includes standard ABS, electronic stability system and eight airbags -- two front, four side and two side curtains.
Bob Hill can be reached at 503-294-4103 or
bobhill@news.oregonian.com. For online archives of recent DriveTime reviews, go to
www.oregonlive.com/info/drivetime.Mercedes-Benz brings back its diesel cars