Citroen C4 Cactus Airflow chases 141 mpg

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The Cactus Airflow in its natural environment - the wind tunnel

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Citroen has never been one to follow convention in the automotive world. The French manufacturer is best known for its DS, which coupled pioneering hydro-pneumatic suspension with a gorgeous aerodynamic body to wow crowds at the 1955 Paris Motor Show. Fast forward to 2014 and Citroën is again using the Paris Motor Show to showcase its innovative creations, this time in the form of the C4 Cactus Airflow 2L Concept.

Based on a C4 Cactus SUV, the Airflow is in response to a fuel efficient vehicle program set up by the Plateforme de la Filiere Automobile (Automotive Industry Group) in France. Thanks to a raft of aerodynamic changes and Peugeot/Citroën’s Hybrid Air system, the Cactus Airflow should reach the Industry Group's fuel economy target of 2l/100km (141 mpg).

If the Airflow moniker didn't give it away, Citroën has paid particular attention to the C4 Cactus' aerodynamics in the quest for better fuel economy. The car's front bumper takes advantage of three variable-geometry air intakes, which constantly adjust to facilitate a smooth profile or let more air into the engine. Mobile air deflectors guide the air flowing around the car, and the car's "Air Curtain" wheels are fitted with shutters that are controlled by centrifugal force.

Not all of the Airflow's aerodynamics are active: small slats fitted to the ends of the front bumper channel air along the wheels and the extended rear spoiler has been coupled with an air-extractor in the rear bumper to cut down on drag-increasing turbulence. The car's underbody has also been made smooth in search of better fuel efficiency.

The car sits on 19 inch “ultra ultra” low rolling resistance tires, which are tall and narrow for optimum aerodynamics.

Traditional door mirrors also get the boot on the Cactus concept, with slimline rear-view cameras taking their place.

Overall, Citroën claims its changes (which are painted orange on the car) improve aerodynamic performance by 20 percent.

Another enemy of fuel efficiency is weight, so the Cactus Airflow 2L has been put on a serious diet. Aluminum is used for the inner-side members and rear floorpan, and high-yield steel components replace structural chassis elements like the heel board and front-side rails. These aluminum and high-yield components are supplemented by composites used in the car's floor, and contribute to 100 kg (220 lb) of weight saving, or 11 percent over the standard Cactus.

As well as lightening the car's structure, Citroën has scattered lightweight components throughout the Cactus. Carbon-composite materials make up the concept's springs, tailgate, rear bench, side panels, roof and roof cross members, wings and doors, while aluminum engine mounts further reduce weight. Even the glass in the car's panoramic sunroof has been replaced by lightweight polycarbonate, a move usually reserved for trackday specials like the RenaultSport Megane.

Power comes from a"Hybrid Air drivetrain, which couples Citroën’s 3-cylinder PureTech engine with a compressed air system to give drivers the choice of three drive modes. In "air power" mode the car is powered by compressed air stored in two composite tanks mounted at the car's rear. When running in petrol-only mode, the Cactus' engine takes advantage of low viscosity oil, carbon-coated moving parts and polymer componentry to reduce fuel-sucking friction, and improves operating efficiency by 5 percent.

When combined in hybrid mode, Citröen claims that the Airflow's HybridAir drivetrain improves fuel consumption by 30 percent over running the engine on its own.

The C4 Cactus Airflow Concept will be displayed at the Paris Motor Show, where Gizmag will be on the ground covering all the action.

Source: Citroën

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