Compressed air hybrid Citroen C3 set for Geneva
Citroen is set to preview a fascinating new drivetrain that uses
compressed air as part of a fully enclosed hybrid system.
Working in much the same way as the well-known hybrid setups
from Toyota/Lexus, the Hybrid Air system combines a small petrol
engine with compressed air and hydraulic power to achieve fuel
economy reportedly in the region of 97mpg.
It has no need for batteries and weight has been minimised as a
result. The prototype, fitted to a C3 with a 1.2-litre VTi 82
three-cylinder engine, will be displayed at the Geneva Motor Show
alongside information detailing its low nitrous oxide and CO2
emissions; the latter of which is just 69g/km.
Citroen cites 80 patents having been registered in the
development of the system, which at low engine loads shuts down the
combustion cycle and instead transfers energy from compressed air
to the wheels via a hydraulic motor and gearbox. This `Air Mode'
can be active up to 43mph, and Citroen estimates that a typical
driver will spend 60-80% of their urban driving time in this
The compressed air tank can be `recharged' by recovering energy
from braking and decelerating, with on-board systems compressing
air and re-filling the tank.
The system can also be used in petrol-only mode when speeds rise
above 43mph or when the compressed air tank is empty. Finally there
is a combined mode, where the two propulsion streams give faster
acceleration than either could manage alone.
Pricing for the new system can be kept down, since battery
production costs are avoided altogether, and Citroen boasts that
the system, which operates through an epicyclic transmission,
always operates at the same efficiency levels regardless of driving
conditions or weather - although this doesn't mean it will always
achieve the same miles per gallon.
Special new low rolling resistance tyres from Michelin help to
lower fuel consumption further.
- Click here for more news from across the county...