Concepts · 2007
An S-Class that sipped.
Frankfurt, 2007: Mercedes rolled out a five-meter touring sedan powered by a 1.8-liter four-cylinder — and claimed the comfort of a flying carpet.
The star of the Frankfurt Motor Show that year was not really a car. It was an engine the size of something you’d find in a C-Class, dropped into a machine longer than the long-wheelbase S-Class, and named after two nineteenth-century inventors at once: DiesOtto.
Rudolf Diesel. Nikolaus Otto. Gasoline that could burn like diesel. Around it, Mercedes wrapped a research sedan called F 700 — aqua-dynamic bodywork, coach doors, and lasers in the headlamps that read the road before the wheels did.
Chapter I
Petrol that thinks it’s diesel.
The DiesOtto was a twin-turbo 1.8-liter four-cylinder gasoline engine with direct injection and variable compression. On cold start and under hard load it fired with spark plugs, like any petrol engine. At cruise, it switched to controlled auto-ignition — a lean mixture that lights itself under pressure, diesel fashion, without the soot.
Output: 175 kW (238 hp) and 400 N·m, plus a 15 kW hybrid module for takeoff. Performance matched a contemporary S 350. Consumption did not: 5.3 liters per 100 km, 127 g/km of CO2 — roughly half the S 350’s appetite.
Mercedes said the technology could reach production within five years. It never quite did as a pure DiesOtto. The ideas inside it — downsizing, turbocharging, stratified combustion — reshaped every gasoline Mercedes that followed.
The F 700 itself weighed about 1,700 kg, lighter than a base S-Class of the day, because a small engine lets you build a lighter car around it.
- Displacement
- 1.8 L
- System power
- 238+20 hp
- Consumption
- 5.3 L
- per 100 km
- CO2
- 127 g
- per km
“A flying carpet that glides over uneven surfaces.”
Chapter II
Reading the road before you hit it.
PRE-SCAN was Active Body Control with foresight. Two laser sensors in the headlamps mapped the road surface; the hydraulic suspension then leveled each wheel for the bump that was still meters away. Mercedes billed it as the world’s first car that could anticipatively recognize road condition.
Six years later the idea reached production as Magic Body Control on the W222 S-Class — with stereo cameras instead of lasers, but the same promise: the car sees the pothole first.
The body around it was “Aqua Dynamic” design — fish-flow surfaces carried over from the Bionic Car — with a 3.45-meter wheelbase, coach-style rear doors and teardrop glass roof panels. California’s Advanced Design studio shaped a touring sedan that looked nothing like the W221 it was meant to succeed.
Epilogue
The engine that almost was.
DiesOtto never badge-engineered its way into an S-Class. HCCI gasoline combustion proved brutally hard to industrialize. What survived was the comfort argument: PRE-SCAN became Magic Body Control, and every modern Mercedes hybrid still chases the F 700’s trick of making a small powerplant feel like a large one. The research car sits in the museum as a reminder that Mercedes once tried to reinvent the spark-ignition engine from first principles — and got halfway there.