In the past I've written about cars that run on air (compressed air hybrid technology) and have been unconvinced that it's much more than, well, hot air. However, last week at the Geneva Auto Show, I saw another variation on the theme that appears to be more sensible and could possibly reach the mass market by 2016.
It's called the Hybrid Air and it's a prototype from the French auto maker PSA Peugeot Citroen. PSA is the second-largest car maker in Europe (after Volkswagen) and PSA claims that Hybrid Air is better, cheaper and simpler than hybrid electric systems from manufacturers like the hybrid leader Toyota Prius.
The Hybrid Air is a gasoline-hydraulic hybrid and not a gasoline-electric hybrid. Let me explain. The Hybrid Air uses a 1.2-litre, three-cylinder gasoline engine and a hydraulic motor under the hood to drive the front wheels. Like a Prius, the Hybrid Air system recovers energy each time the vehicle brakes or decelerates; but instead of capturing the energy with a generator that charges a battery, the Hybrid Air system uses a reversible hydraulic pump to compress nitrogen gas in two carbon-fibre tanks under the floor.
When you hit the accelerator, the compressed gas pushes hydraulic fluid through the gearbox to turn the wheels. The amount of energy that is stored is small, but it gives you a boost, and can even briefly replace the gasoline engine, at the times when you consume the most energy – which is starting and acceleration.
PSA claims that in city driving, depending on traffic, you can save 45 per cent of fuel while running with the gasoline engine off 60 to 80 per cent of the time. I have no way of knowing if this is true or not, but the main advantage of Hybrid Air over Hybrid Electric appears to be cost.
PSA says it can undercut existing hybrids significantly on price because the Hybrid Air does not require an expensive battery and electric motor. It is hoped that Hybrid Air could be viable even in emerging markets like China and India where gasoline-electric hybrids are expensive and complex to repair.
PSA Peugeot Citroen needs this to be a winner. The automobile market in Europe is a disaster and, last month, PSA reported a loss of $6.6-billion for 2012. General Motors bought a 7 per cent stake in the French company last year, but has not yet signed on to the Hybrid Air technology. PSA admits it must partner it with someone to cover development costs.
As well as the technical challenge of developing a brand-new innovation, there is the perhaps larger problem of achieving market acceptance.
Hybrid electrics, plug-in hybrids and battery-powered electric vehicles, all of which have a big head start in the market, have all been slow starters with customers. Are we ready to start driving around with high-pressure tanks under the floor? What if the hydraulics spring a leak?
Nevertheless, I found the Hybrid Air to be the most interesting new technology on display in Geneva.
The various forms of electric hybrid certainly save fuel, but nobody has come up with the answer on electricity storage. If they have, they haven't told you and me because that would make their current inventory of lithium ion and nickel metal hydride battery vehicles unsellable. Heavy, expensive, slow-to-charge, fast-to-discharge batteries are holding back hybrid acceptance.
Maybe a cheaper, simpler Hybrid Air can get us around the whole battery problem. It hasn't happened yet, but what I saw at Geneva with PSA Peugeot Citroen suggests an interesting possibility.