Well, it looks like Citroen has managed to make a car that runs on air! The Citroen Hybrid Air technology is a clever system that combines a petrol engine, compressed air and hydraulic power to achieve an amazing fuel economy of 94 mpg (less than 3l/100km) and CO2 emissions of 69 g/km.

To be more precise, the system consists of a PureTech petrol engine, a compressed air energy storage unit, a hydraulic pump/motor unit and an automatic transmission with an epicyclic gear train. It offers three modes: Air, Petrol, and Combined.

The interesting bit is the zero-emission Air mode – active up to 43mph (70kph) – in which compressed air is used to spin the wheels. Citroen does not get into details on how it works. They have, after all, filled more than 80 patents developing this technology.

Compared to a normal hybrid, this system has no batteries, which means you don’t have to worry about charging them or their heavy weight. It is also fairly compact and has no impact on interior space or boot capacity and is essentially mechanical, which means it is easy to service and repair.

Citroen really seems to be onto something here. How awesome it is having a car that runs on air. They will showcase this technology on a C3 Hybrid Air prototype at the Geneva Motor Show.