Diesel technology has improved by leaps and bounds, but the trouble is, it still runs on diesel. In the American market, at least, finding a diesel pump is still a pain compared to filling up with conventional gasoline. Mercedes-Benz says it's found the solution with a new developmental powertrain concept it calls DiesOtto.
We first reported on the project a couple of years ago, but the German automaker now has a functioning prototype. Rather than actually running on diesel, the DiesOtto engine is said to incorporate the benefits of a diesel engine, but runs on regular old unleaded. The prototype is a 1.8-liter four-cylinder engine that uses direct injection, variable compression, turbocharging and something MB calls "controlled auto ignition" to deliver 238 horsepower and 295 lb-ft of torque, with a claimed return of "less than 6 liters per 100 kilometers", which translates to 39.2 mpg. Those numbers, Benz claims, are not based on a small car (like the C-Class or smaller) but on a large sedan (like the S-Class). They may not be entirely revolutionary figures, but any way you look at it, they're damn impressive.
Mercedes hasn't put a timeline on producing and marketing a powertrain based on the DiesOtto prototype, but says it's a "feasible proposition in the midterm". We certainly hope so.