Citroen's latest fuel-economy focused concept car promisies to cut consumption by 30 percent by storing waste kinetic energy as compressed air which can power the car for short distances with zero emissions. Matthew Stock reports.
STORY: This is the C4 Cactus airflow, the latest concept car from French manufacturer Citroen. It's an upgrade on the existing Cactus production model that promises to cut fuel consumption drastically - delivering a range of 100 kilometres on just 2 litres of fuel. It pairs a petrol engine with HybridAir technology, which - as Citroen's Pierre Monferrini explains - uses waste kinetic energy to compress air which can then be used to help provide thrust. (SOUNDBITE) (English) HEAD OF PROJECT FOR CITROEN RANGE PIERRE MONFERINI SAYING: "On the front you have an optimised petrol engine of 1.2 litres, on the rear, under the trunk, you have a compressed air tank then, when you decelerate, the engine compresses the air and when the car restarts, when you go forwards the compressed air helps the car to move so you save a lot of energy and a lot of fuel." The prototype is lighter than the current production model and has enhanced aerodynamics, including front air intakes on the bumper and shutters on the wheels which automatically adjust to improve airflow. Monferini says the HybridAir powertrain stores the compressed air in tanks that are lighter and less expensive than equivalent lithium-ion batteries. (SOUNDBITE) (French) HEAD OF PROJECT FOR CITROEN RANGE PIERRE MONFERINI SAYING: "It's more simple, it works in very bad climate conditions for example, in all countries, it doesn't use some expensive materials like lithium for example so it has a lot of advantages." All in all Monferini says fuel consumption can be reduced by up to 30 percent. Citroen's French rival Renault also presented its small concept car, which only has three gears; the first two working with the electric engine and the third gear starting the petrol engine. It boasts an ambitious target of just one litre of fuel per 100 kilometres. Time will tell if battery power or air power or a combination of both will prove the most efficient way forward. Europe's car sales are on the up again after a six-year slump, and car companies are hoping to gain market share by offering hybrid cars to combat rising fuels costs and a stagnant EU economy.