Peugeot will unveil the 208 Hybrid Air 2L during this year Paris Motor Show. The car is just a concept, meant to explore the alternative of a hybrid architecture, which uses a compressed air engine, along a conventional petrol unit.
HYbrid Air technology uses compressed air to assist and even replace the petrol engine to enable maximum efficiency during transition phases, such as acceleration and starts.
The system includes a compressed-air tank below the boot, a low-pressure tank near the rear axle acting as an expansion chamber, a hydraulic system consisting of a motor and a pump in the engine bay. 
In Air mode, the 208 Hybrid Air 2L runs only on compressed air. This mode does not consume fuel emits 0 CO2. In Petrol mode, the car is powered only by the petrol engine, which is suitable for travelling on main roads and motorways. The Combined mode is designed for transition phases in urban environments and on the road, such as standing starts and acceleration. The compressed-air tank is recharged like an electric battery: while braking or taking the foot of the pedal or by using the three-cylinder petrol engine to compress the air.
In addition, the design was modified to improve aerodynamics. It has a lower stance with smaller air intakes, a tailgate spoiler and an air extractor and efficient underbody fairing.