It won’t be the compressed air car but it is the closer step to the utopia that it’s possible today. We used to think about hybrid as the union between heat engine and the electrical one but in the following years “not so far according to the road map written by PSA” we could extend the concept, replacing the electrical component with the air.
Avoiding any mistakes, we talk about an optimization of system, an assistive device which can reduce the fuel consumption and really introduce itself in the market, waiting for something to supplant the conventional engines.
At the Geneva Motor Show 2013 the PSA group presented Hybrid-Air, the new way of hybrid, a system able to solve problems concerning cars with electric engine, that is the strong increase in weight due to the use of batteries that puts in operation the electrical unit and store energy otherwise lost as heat during deceleration.
Hybrid-Air has a simple scheme with its two compressed air thanks very similar to the bi-fuel ones at LPG or CNG, which ensure the “fuel” for the hydraulic unit.
How does it work? For a while let’s divide the thermal unit, clearly used to play the same rule, from the automatic gearbox the system core. Outside the slot we can see a pump and an hydraulic engine, responsible for double functions: they charge the air cylinders during deceleration and braking, they work on the gearshift and give back air, previously stored, in the form of torque.
Hybrid-cars advantages are generally put in evidence in the city because of the continuous stop&go and slow paces particularly not favorable to common thermal engine. Among the driving opportunities there is a zero emission mode, however, still waiting for feedback on the street- the first model will be put in the market in the 2016 and it will be a B-segment product- but the combined modality holds the interest.
Up to 70 km/h you can move only with the pressure of the compressed air, while the combined effort between the heat engine and hydraulic one shows its own advantages in the restarting and acceleration phases with a torque boost, this still to be defined in numbers and Newtonmetres as well. We know, however, the “combination” with thermal engines, that is 82hp for an economy car and 110hp for a touring car.
Going back to the diagram of operation, there are two air cylinders where compressed air is stocked: one at the backside at low pressure (a proper tank which is charged under the action of the hydraulic pump mounted on the gear) and the second one is placed to the centre of the platform. This is then pressurized and its rule is to activate the hydraulic motor in turn operating on the gearbox and transmission.
Another important aspect about the comparison between the two hybrid models - the electric car and the air one – concerns the battery maintenance of costs compared to air cylinders, clearly inferior for the second ones. You could wonder why we should prefer the hybrid choice. According to statistic studies there is a good relation between CO2 emissions and price list of models.
Faced with a value of 69g/Km, a hybrid air B-segment should place itself in the market sector of 15-20 thousand euro, approximately the price of the only two hybrid electric products in this category: Yaris and Jazz, but they can’t do better in emission than 79g/km.
Translated by Federica Izzo
