Just when you thought the whole world was turning diesel, Mercedes comes up with a new petrol-powered powertrain.

Unveiled in the swanky F700 concept that looks conspicuously like the future of S-class, the all-new 1.8-litre petrol hybrid offers the performance of a large 3.5-litre V6, but with vastly superior economy and emissions that would give even the finest diesels a decent run for their money.

The show car is said to average 53.3mpg yet sprints to 60mph in under 7.5 seconds, while the 1.8-litre uses direct injection and turbocharging plus electric motors to boost power to 258PS.

Other technological breakthroughs starring on the F700 include the ability to read the road with infrared sensors and adjust its suspension accordingly to ensure that ride comfort always remains paramount.

Mercedes will replace the current S-class come 2012.