PSA Peugeot Citroen will unveil two cars today which feature its new diesel-electric hybrid powertrain.

The engine will be shown in the Peugeot 307 and the Citroen Hybride HDi. Average diesel consumption for these two cars is 3.4 litres per 100 kilometres, with 90 grams of CO2 emitted per kilometre. Peugeot says this is 25% better than a similar vehicle equipped with a petrol hybrid system, or as much as a litre per 100 kilometres in combined urban and motorway driving.

PSA Peugeot Citroen’s Hybrid HDi technology comprises a 1.6-litre HDi diesel engine, a particulate filter system (DPFS), the latest generation Stop & Start system, an electric motor, inverter, high-voltage battery pack and control electronics. The cars are also equipped with an electronically managed manual gearbox.

The Hybride HDi features recovery of kinetic energy during deceleration and braking, all-electric mode and an extended all-electric mode mode, in which electrical power is used by default, depending on the battery charge level.

For main road and motorway driving, the electric motor can provide a 35% power boost for extra acceleration when needed.

PSA said it could market its Hybride HDi vehicles as early as 2010. However, their introduction rests on making this technology available at an affordable price.

The price gap between a Hybride HDi model and a comparable diesel HDi model is still too wide and would have to be halved to make diesel hybrid vehicles accessible to most consumers, said PSA.