The Frankfurt Auto Show gets underway tomorrow, and, according to the New York Times, European automakers, stung by criticisms from environmentalists and government regulators that they are late to the green party, are using it to showcase everything in their alternative fuel and powertrain arsenals.

Over the next week we’re going to spotlight a few new green models so we can enjoy their shiny greenness. First up, the Mercedes F700 concept…

The centerpiece of the newly emancipated DaimlerMinusChrysler is the F700 concept, an S-Class-sized vehicle with five doors and 40 miles per gallon economy. The F700 is a rolling test bed of new environmental technologies, including the DiesOtto engine. This four-cylinder gasoline engine, pronounced “Dees-Otto” (not De Soto), produces 238 horsepower and 295 foot-pounds of torque from just 1.8 liters , using a new technology known as homogenous charge compression ignition. The engine has two ignition modes — compression, under light loads, and spark at other times — to boost fuel mileage. The company said the DiesOtto engine has the strong low-end torque and fuel savings of a diesel, but with emissions that are lower than a diesel.

More to come over the next week.