The programme was set up by the French government with the objective to reduce the impact of vehicle running costs on household expenditure and to reduce the eco-footprint of car travel.

Citroën's response to the project uses its newest model – the C4 Cactus – with the carmaker saying that the vehicle lent itself to the task of developing a very-low consumption high-tech concept that is both efficient and attractive more than other.

The resultant C4 Cactus AIRFLOW 2L concept – which will be displayed at the Paris Motor Show – delivers consumption of 2l/100 km – 141mpg – through the use of various measures including the implementation of Hybrid Air technology, which cuts fuel consumption by 30%.

The drivetrain includes a three-cylinder 1.2-litre PureTech petrol engine that’s already part of the C4 Cactus line-up along with a compressed air energy storage unit, a hydraulic pump/motor unit and an automatic transmission with an epicyclic gear train. An intelligent electronic management system manages input from the driver to optimise energy efficiency.

Three operating modes are available:

• Air power (zero emissions) where the compressed air motor takes over from the petrol engine
• Petrol power, using only the combustion engine
• Combined power, drawing upon both the combustion engine and the compressed air

Other features include optimised aerodynamic design including lower rolling resistance (“tall & narrow” tyres), with an overall 20% improvement in aerodynamics, and use of lighter parts such as carbon-based composite materials, which shaved a further 100kg of the overall vehicle weight by 100kg. 

Both Peugeot and Renault have also unveiled ultra fuel-efficient models in response to the French government's challenge.