A new stage, significant for the reduction of fuel consumption, ultimately involves the hybrid diesel technology, in which an HDi DPFS engine is coupled with an electric motor. The central system management unit controls the three main operating modes of both the heat engine and the electric motor: the electric motor operates alone at low speed and during deceleration and the heat engine operates alone at stabilised speed on highways and motorways, while for sharp acceleration both motors operate simultaneously.

For equivalent power, this technology provides a fuel consumption and CO2 emission saving of approximately 35% by comparison with the conventional diesel engine.

Developments made since the presentation of the first 307 HybrideHDi demonstrator in 2006 confirm the validity of the initial strategic and technical options.

The latest concept car, the 308 HybrideHDi presented at the 2007 Frankfurt Motor Show, has a 1.6-litre HDi DPFS heat engine of 80 kW (approx. 110 hp) combined with a 16 kW electric motor (approx. 22 hp). Its combined cycle fuel consumption is 3.4 litres per 100 km, with 90 g/km of CO2, i.e. a 38% gain by comparison with the equivalent 308 HDi.