How Peugeot-Citroen's Hybrid Air System Works: The Car That Runs on Air

Peugeot-Citroen's Hybrid Air System

Hybrid cars seems to be the mantra of the automobile industry to garner fuel efficiency. While other car companies are relying on the conventional battery to save fossil fuel, Peugout-Citroen has rather opted an unconventional fuel 'Air'.

You see, Citroen has always been the sort of car company that has a strong fascination with fluids and gasses, long before Toyota made its first Prius. And so, when they decided to invent the new hybrid engine, they replaced the hardy donkey, the electric motor, with a puffer fish, an air compressor. We'd call it the "Puffahorse" (like a Pokemon), but Citroen call it simply "Hybrid Air".

Air Hybrid System explained

But first, let’s talk physics. In simplified terms, combustion engines transform fuel into power, which is then used to propel the cars up to speed. But all the energy used to get you up to speed is then wasted when you have to brake again, as calipers bite into your disk rotors and slow you down using friction force. The fact that your brakes are really hot to the touch is the most obvious indication that, from a kinetic point of view, you are wasting energy.

Conventional hybrids get around this problem using electric motors and generators. Instead of slamming on the brakes, they convert the braking energy into electricity which is then stored into a battery. The distance a car travels while braking looks very small because modern disk brakes are very strong, so it might seem like an insignificant problem, but in theory hybrids recapture the energy used to get you up to speed in the first place.

Hybrid Air Setup in the car

Hybrid Operating System explained

The Hybrid Air system uses much the same principle to run. It still uses a conventional but very efficient 3-cylinder combustion engine for highway cruising, but also has a motor that runs on air around town. This is stored in a pressurized tank situated in a tunnel under the middle of the car is compressed using a regenerative braking pump.

Just like a hybrid can run on petrol or electricity, or a combination of the two, so too will Citroen’s system run on gasoline or air, or both. Air power would be used only during city driving, automatically activated below 43mph (70 km/h) and available for ‘“60 to 80 percent of the time in city driving,” according to the French. The air tank has enough pressure for a daily commute of up to 50 minutes under ideal conditions, a lot better than the 15 or so km range some hybrids of today offer.

Currently the concept is under research and the feasibility study is still going on and the system may only be introduced by 2016 as of now Hybrid Air is only the stuff of prototypes and dreams. But the automotive world will definitely welcome a cheaper, simpler to service hybrid with few compromises.

Here's a video below for better explanation of the concept.