PEUGEOT is showcasing its 208 HYbrid Air 2L Demonstrator at next month’s Paris Motor Show. The 2L stands for two liters per 100 km, equivalent to 118 mpg US, and is based on a production version of the Peugeot 208 1.2-liter PureTech 82 hp 5-seater Hatchback.

Peugeot’s Hybrid Air is a full-hybrid solution combining compressed air and hydraulic power, with no battery required for energy storage. Hybrid Air combines the PureTech gasoline engine; a compressed air energy storage unit located beneath the trunk; a hydraulic pump/motor unit in the engine bay; and and an automatic transmission with an epicyclic gear train.

The compressed air is used to assist and even replace the gasoline engine to enable maximum efficiency during transition phases, such as acceleration and starts.

• In Air (ZEV) mode, the car runs on compressed air alone. This method of driving does not consume fuel and gives off no CO₂ emissions, making it ideal for urban environments.
• In Gasoline mode, the car is powered only by the 1.2-liter gasoline engine. This is more suitable for travelling at a steady speed on main roads and highways.
• The Combined mode is designed for transition phases in urban environments, such as standing starts and acceleration. It draws on the two energy sources in proportions adjusted to achieve optimal fuel consumption.

The compressed-air tank is recharged when slowing down (while braking or taking the foot off the pedal) or by part use of the energy developed by the three-cylinder engine to compress the air. Both methods can achieve maximum pressure in just 10 seconds.

At the 2013 Geneva Motor Show, Peugeot showed an application of the Hybrid Air powertrain in a 2008 crossover.

Weighing just 860kg—100kg less than the production car—the 208 Hybrid Air 2L demonstrator is a mix of steel, aluminium and composites. Engineers selected only those materials compatible with existing production facilities and a high manufacturing output. In addition, the process involves reducing consumption without altering the car’s characteristics, retaining a style synonymous with high-end products and services.

Carbon composites are used for the body panels, sides, doors and roof, along with the coil springs providing suspension. In the latter case, the use of composites has a positive impact on dynamic handling by reducing unsprung weight. The car has also been fine-tuned aerodynamically, with a number of improvements to reduce drag, including a lower stance on the road.

The campaign to reduce weight has not focused solely on the use of new materials; it has also sought to redesign existing parts. This has led to changes in the thickness of the stainless steel exhaust system, enabling a 20% improvement on this part alone.