Gasoline hybrid pneumatic engine for efficient vehicle powertrain hybridization

• The hybrid pneumatic powertrain is an alternative solution for hybridization.
• The main advantages are the low cost and the direct transmission of the torque.
• The hybrid pneumatic powertrain suits for urban driving and mild hybridization.
• An efficiency improvement of 50% is reached for urban driving and C Segment vehicle.
• The CO2 emissions on the urban cycle are very low – only 51 g CO2/km.

The largest applied convertors in passenger cars are the internal combustion engines – gasoline, diesel, adapted also for operating on alternative fuels and hybrid modes. The number of components that are necessary to realize modern future propulsion system is inexorably increasing. The need for efficiency improvement of the vehicle energy system induces the search for an innovative methodology during the design process.In this article the compressed air is investigated as an innovative solution for hybridization of small gasoline engine. The combination of a conventional IC engine and a pneumatic short-term storage system is an interesting approach to achieve lower fuel consumption. Instead of using a battery, a hybrid pneumatic vehicle uses a robust and inexpensive air pressure tank for energy storage. The fuel consumption benefit of the hybrid air system is assessed and the vehicle usages leading to the maximal fuel consumption benefits of the hybrid pneumatic powertrain are investigated.The hybrid pneumatic concept is applied on a largely deployed C Segment commercial vehicle with 3 cylinder gasoline engine. The lowest fuel consumption results are investigated on the usage of this vehicle.