With CAI, when the engine is started or on full load, the air and fuel mixture is ignited by the heat created during the compression stroke - not by a spark plug, as in a conventional gasoline engine; hence the reference to diesel technology in the DiesOtto name (Otto refers to Nikolaus Otto, the German engineer who invented the four-stroke internal combustion engine in 1876, and the nickname Germans give to gasoline-powered cars). And with auto ignition, at low to medium engine speeds combustion occurs at much lower temperatures than during spark ignition--about 1200 degrees Celsius versus 2000 degrees Celsius. This results in fewer emissions of nitrogen oxides. 

Mercedes expects that DiesOtto can provide, on average, about 100 kilowatts, or 134 hp, per liter of displacement, and about 160 lb-ft of torque per liter. Thus, the 1.8-liter four-cylinder produces some 238 hp, and the hybrid module's electric motor kicks in another 20 hp during initial acceleration. The total torque figure of about 300 lb-ft is pretty amazing given the engine's small displacement. The 0-to-60-mph time is 7.5 seconds, yet fuel economy in this big, luxurious sedan is estimated to be about 44 mpg.

Aside from the powertrain, the F700 boasts some other cool toys. An active "Pre-Scan" suspension uses laser sensors built into the LED headlights to scan the roadway for bumps and holes, then submits the data to a control unit that adjusts hydraulic pressures at each wheel for the best possible ride quality. And the F700 finally presents a solution to the problem of dinged doors: lasers in the base of the side-view mirrors scan the ground where the door is swinging open for obstacles. If the door is about to hit something, hydraulics pull it back closed.

DiesOtto is at least five years away from production. GM and other automakers are working on similar systems. But it's interesting to note that many previous Mercedes-Benz "research" cars showcased seemingly outlandish technology that later made it into production cars, such as Distronic laser cruise control and the Active Body Control suspension.