Dubbed C4 Cactus Airflow 2L, not one of the eye-catching external features of this concept could possibly match its official fuel figure for headline-grabbing glory: just 2.0 l/100km.
That’s 141.2 miles per gallon in the ‘old’ language, or 117.6 MPG if you live in the US. More importantly, it means the days of the unofficial ‘race to 100 MPG’ among the French carmakers are long gone.
Officially, the Airflow is Citroen’s answer to a challenge from the French government to create a 2.0 l/100km car.
To achieve this remarkable fuel figure, Citroen has made a ‘regular’ C4 Cactus lighter and 20 percent more aerodynamic.
Power comes from a ‘PureTech’ 82 three-cylinder petrol engine combined with ‘Hybrid Air’ compressed air propulsion technology, which alone reduces fuel consumption by 30 percent.
The concept is 100kg lighter than the regular Cactus at 865kg, with carbon-fibre, aluminium, high-yield steel and translucent polycarbonate all used in its construction.
A range of ‘variable geometry’ components are perhaps the real stars of the show, including a front bumper than can continuously adjust airflow for both engine cooling and aerodynamics.
Side deflectors have been fitted to guide air away from the body, while the wheels contain ‘shutters’ which are controlled by centrifugal force and wear tall, narrow tyres from Michelin with low rolling resistance.
Non-variable components have also been optimised for fuel economy, including ‘air curtain’ wheel arches and rear-view cameras in place of conventional side mirrors.
No mention from Citroen on what a road-going version of the concept - complete with the full kit of fuel-saving tech - might cost.
Potential owners wishing to replicate that 2.0 l/100km fuel figure regularly might want to consider the engine’s longevity, as the French carmaker used “very low viscosity” oil to achieve it.
The regular Citroen C4 Cactus is under consideration for the Australian market, and in its most economical guise can use as little as 3.1 l/100km.
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