No automobile company has a longer history with diesel engines than Mercedes-Benz. At the launch of the brand's new 50-state BlueTEC diesel SUVs, Mercedes-Benz had a display of several of its significant diesel-powered cars through the years.
Mercedes-Benz claims that the 260 D, introduced in 1936, was the first diesel-engine passenger car. This 1939 model was slightly reworked compared to the first-year cars, with a four-speed transmission, and was one of four body styles offered: Six-seat Pullman sedan and Landaulet, 4- or 5-seat sedan, and 4- or 5-seat Cabriolet B.
Mercedes-Benz began fitting a diesel engine to its "pontoon" sedan one year after the model's introduction in 1953. For '55, power increased from 40 hp all the way to 43 hp. This is the car with which Mercedes-Benz initiated diesel sales in the USA, in 1960.
The 1968 200 D is a classic example of the "fintail" Mercedes sedan, which first appeared in 1961. By the time this 1968 model arrived, Mercedes had sold 360,000 diesel-powered fintail sedans, a number bolstered, no doubt, by the availability of an automatic transmission, which was first paired with the diesel engine in the 1963 model year. The 200 D and the 220 D were the two diesel offerings for 1968. The four-cylinder 200 D cranked out all of 55 hp, giving the car a 0-to-62-mph time of 28 seconds and a top speed of 81 mph.
The C111-IID and the C111-III streamliners helped the diesel engine shed its reputation for pokiness. Both used the five-cylinder engine configuration, which first appeared in production cars in 1974. In this C111-III, the turbocharged 3.0-liter boasted an output of 230 hp. During a series of speed record runs on a racetrack in Nardo, Italy, the C111-III reached speeds just shy of 200 mph. That same year (1978) saw the introduction of the turbocharged diesel engine in the U.S. market, making 115 hp from five cylinders.
The turbo-diesel engine first appeared in the U.S. S-Class in 1978. Interestingly, a turbocharged diesel wouldn't appear in Europe until 1980 (in the 300 TD station wagon) and a diesel S-Class wouldn't be offered in Germany until 1992. Diesels had become very important to Mercedes' U.S. market, so much so that in the following year, 1981, four out of five Mercedes sold in America were diesels.
Direct injection technology came to the diesel engine in the 2000 C220 CDI. Direct injection ushered in the modern diesel era, paying benefits in fuel economy, smoothness, power, and, especially, torque. (The 221 lb-ft of torque in this C-Class doubled the torque output of the previous diesel.) In the USA, however, interest in diesel engines had waned, and Mercedes-Benz did not, and still does not, offer a C-Class diesel in the U.S. market.
Mercedes' U.S. diesel engine had grown to six cylinders, and a V configuration, by the time this 2005 E320 CDI took part in a 100,000-mile, high-speed endurance drive. Teams of six drivers drove each of the cars 20,000 laps over a track in Laredo, Texas, running 24 hours a day and averaging more than 136 mph.
The arrival of ultra-low-sulfur diesel fuel to the U.S. market in October 2006 set the stage for the introduction of the cleaner-burning E320 BlueTEC. The new diesel engine also provided Mercedes-Benz with the excuse to undertake another high-profile endurance drive, as three E320 BlueTECs joined a fleet of E320 CDIs trekking from Paris to Peking. Automobile Magazine's own Joe DeMatio, sharing wheel time with Denise McCluggage, drove one of the U.S. cars on the last leg of the trip.
Vision GLK BlueTEC hybrid
The Mercedes GLK BlueTEC diesel hybrid concept points to a possible future that merges clean-burning diesels and hybrid technology for even bigger fuel economy and lower emissions. The compact SUV pairs a 2.2-liter diesel with an electric motor for a combined output of 224 hp and 413 lb-ft of torque, with an estimated average fuel consumption of 40 mpg. No word yet on when this next chapter in the diesel story will see production.