Running on air

Transport: Powering hybrid cars with compressed air rather than electric motors could be a cheaper way to increase fuel efficiency

See article

Readers' comments




An interesting article; but a misguided idea - hybrids of any type are an un-necessary, heavy and expensive combination - and a distraction from the real solution.

Moving to electric only vehicles for urban use solves all the problems:
- no complicated petrol or diesel engine & their systems (eg exhaust, oil, ignition, fuel tanks, cooling radiator & pipework)
- no complicated gearbox & drivetrain and their systems (propshafts, driveshafts)
- only a handful of moving parts, few of which need any maintenance during the vehicle's lifetime.
- very low (especially fuel & maintanence) running costs; a vehicle as easy to own as a hoover.
- transforms the quality of life in urban areas by reducing foul emissions and vehicle noise

For these very reasons, electric cars have been opposed & ferociously resisted by the oil industry (who lose their so lucrative monopoly) & the car industry (who make most of their money selling replacement parts which electric cars don't need [filters, spark plugs, clutches, exhausts, brake pads, etc] & maintenance) & the garage & filling-station sector (who are redundant) & even governments (who currently gain billions from fuel taxes).

Electric cars will be as big a change as moving from horses a century ago. Many vested interests will suffer.
This is why you hear such nonsense as "electric cars are not green - power stations recharge them". Ignoring that power stations generate energy many times more efficiently than an infernal combustion engine - and that power stations can be modified to be even cleaner than now - the real benefits of electric will be cities with air fit to breathe and cars as easy to own as a domestic appliance. Their batteries have an effective life of eight years and an adequate range for most users (certainly for the home's second car). Electric won't suit everyone - efficient diesel vehicles designed for economy rather than acceleration will meet the needs of "road-warriers".

Hybrids are great for protecting oil company and car manufacturer, but are a lousy deal for consumers.


Using a normal car engine for compressed air would result in fairly low pressure. The pistons are large and the compression ratio quite low. This limits the energy that can be stored from normal braking. The incoming air will cool one or more pistons and result in uneven engine heating. There will be a weight increase for the air tank of many kilos. Overall I see this as making the car very expensive and more complicated with probably more maintenance.

Using compressed air from diesel engines to power air starts is better than the current practice of dumping the Jacobs Brake air into the exhaust pipe, and will significantly reduce noise. This is a much better application of the system described in the article.


I would still put my money on electric cars with batteries and a fuel-powered generator for additional range. Electric engines are much simpler than hybrids, or internal combustion engines for that matter. The motor for the generator, because it is not attached to a transmission, can be simple and small, running at a single efficient high speed. How about a natural gas powered gas turbine, for instance?

Friend of Speckled Hen

The idea sounds absurd in a convential way, yet with thinking out of the box, it sounds like a feasible concept. Since there are no batteries that have a large carbon footprint, a lot of weight and cost a fortune to replace, the idea intrigues me.
Perhaps electric cars are the future, yet to produce the electricity to charge them will also be an issue. There are many ideas in the interim that will lead to the best answer down the road and all must be considered.


In reading your article, I noticed you indicated the Toyota Hybrid has the best fuel econo in the USA. Please check out the 2010 Ford Fusion Hybrid. It's a full Hybrid and with an EPA of 41 city 36 hwy is currently the highest in America. Check it out.



Products and events


Take our weekly news quiz to stay on top of the headlines

