Mercedes F700

Just when it looks like the days of the internal combustion engine are numbered, is it about to be reinvented? The F700’s “DiesOtto” engine runs on petrol but turns its spark plugs off part of the time, using diesel-style compression-ignition to burn fuel more cleanly and efficiently. That combines the advantages of petrol and diesel engines. The curvy appearance of this futuristic large limousine (think S-Class), and its innovative rear cabin with one backward-facing, one forward-facing seats (for better conversations) may or may not appeal. But if Mercedes can make the DiesOtto engine do what they claim it will, this concept marks a genuinely historic development.