Mercedes Benz F 700 with DIESOTTO engine

The Mercedes Benz F 700 was unveiled at the 2007 Frankfurt Motor Show, but was exhibited again at the Tokyo Motor Show a few weeks later. It’s what Mercedes Benz thinks a luxury long distance touring saloon of the future ideally should be, so we should expect it to point to the direction of the next generation S-Class.

Probably the first Mercedes Benz sedan with an A pillar window (hatchbacks like the A-Class already have an A pillar window if I’m not mistaken), the F 700 is certainly looks odd from the outside, with it’s strange curved side window profile, and its oversized front grille with vertical LED strip front headlamps. Mercedes Benz calls this design language “Aqua Dynamic”, which emulates the soft flowing forms of a fish.

But the interior looks fairly orthodox as far as luxury cruiser interiors go, designed to seat a driver and 3 passengers very comfortably. The front passenger seat can be put into relaxation mode - not for the front passenger of course as the seat has to be vacant for it to do this - but for the rear right passenger. The rear passenger seat situated behind the front passenger seat can even be turned around to face the rear of the car - Mercedes rather uncreatively calls this feature the REVERSE seat. He can have face to face conversations with the other rear passenger this way.

Despite the F 700 name, it does not indicate a 7 liter engine under the hood, or even the equivalent of a 7 liter engine. Instead, the engine used to power this concept is the Mercedes Benz DIESOTTO engine concept. This four cyclinder engine puts out the equivalent of a 3.5 liter normally aspirated V6 petrol or a 3.0 liter V6 turbodiesel in Mercedes terms. The name DIESOTTO seems to indicate something related to diesel, but the engine consumes petrol. This is just a guess but the word DIESOTTO is probably some combination of Diesel cycle combustion and Otto cycle combustion.


The DIESOTTO engine has 1.8 liters of displacement but puts out 238 horsepower with smoothness worthy of a luxury tourer thanks to a two-stage turbocharging system. Take-off is also assisted by a hybrid module, which uses a 15kW (20 horsepower) motor - this gives a total output of 258 horsepower and a maximum torque of about 400Nm. The F 700 can reach 100km/h in 7.5 seconds, up to a limited top speed of 200km/h. Fuel consumption is rated at 5.3 liters per 100km, and CO2 emissions is rated at 127g/km.

The engine works like a normal Otto cycle engine on starting and at full load, using spark ignition and the usual works. But at low and medium engine speeds, or generally partial load conditions the DIESOTTO engine uses something similiar to a Diesel cycle - controlled auto ignition or homogeneous combustion. I’ve previously blogged about homogeneous combustion here, so read up if you want to know more on that.

The F 700 at 5.18 meters is shorter than the current S-Class long wheel base, but it’s wheelbase is 3.45 meters, longer than the production model S-class by 28.5cm. Other technologies include PRE-SCAN suspension, which uses two laser sensors in the front headlamp units as “eyes”. These feed the car suspension system information on roadway conditions. This information helps the suspension hydraulic systems precisely calculate fluid flows and pressures for each single wheel, ensuring maximum comfort.