How does a car run on Compressed Air?

Now this is not a scam, unlike the water idea.

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Two types of motor. Single fuel, compressed air only giving zero pollution, in fact cleaning the air as it goes along due to the filters installed. Also a dual fuel engine which uses a small amount of fossil or bio fuel, giving a car which returns up to 140 mpg.

Of course they don't take into account the energy used to compress the air in the first place.

Reply to
Brian
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On Tue, 13 May 2008 14:59:57 +0100, Brian wrot= e:

So it's not a scam unless they've convincde you to invest in it.

Reply to
Duncan Wood

I assume from this comment that you don't believe it's possible. Well, only time will tell. Certainly compressed air can be used to power a vehicle, when you think about it, it's no different to steam in that respect. Or don't you believe steam engines work either?

Reply to
Brian

Hmmm, maybe if steam engines didn't produce steam and just stored it under pressure it might be a better comparison....

Reply to
Tony (UncleFista)

What, like this?

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Ian

Reply to
Ian

It's perfectly possible, but it won't be very effecient or go very far.

Not very well if you try & store the compressed steam.

Reply to
Duncan Wood

^^^^^^^^^^^^^^ Just a minor detail of course.

Biggles

Reply to
Biggles

Well they claim a range of up to 150 km per charge, which is rather better than you will get with electric propulsion. Add a bit pf petrol and the range goes up to 1000km. I doubt you can get that with your avarage petrol engined car. The cost of recharging is unlikely to be much different to that of recharging an electric vehicle.

Reply to
Brian

Small compressed air cars are used in a village in France as a form of personalised public transport. They cab be picked up at certain stations and workmen collect them in the evening. The range and power is modest, but sufficient for their purpose. Like electric cars, they don't pollute in area where they drive. But of course they don't produce zero net pollution to the global system; they just displace it.

Reply to
johannes

There's plenty of electric prototypes that exceedd that.

The last 3 I've had easily managed that

Because air compressors & battery chargers are very similar?

Reply to
Duncan Wood

And they have used electric cars only in Austrian mountain villages for many years to conserve the idyllic scenery. However, the noiseless operation can be quite hazardous to walkers.

Reply to
johannes

Or the efficiency of that process!

The conversion of high grade energy like electricity into stored mechanical energy as compressed air is only about 10% efficient. Most of the energy expended just makes the air hot and doesn't increase the pressure. If they have found a way of making more efficient compressors then every plant manager in the whole world will be beating down their doors.

The conversion of energy stored in compressed air into rotation to propel a car is also not going to be very efficient, maybe 15%.

Overall efficiency from mains plug to road = 1.5% (100 x 0.15 x 0.1). A typical car engine is 20% efficient from pump to road (25% if accessory load taken into account). If they manage a 40% efficiency for the compressed air motor the overall efficiency is still only 4% as the compressor efficiency cripples the whole process. Produce a super efficient air compressor at around 25% and it's still only 10% efficient overall. Even if initial power is produced from renewable sources it's a huge waste of that resource.

This very poor efficiency is unavoidable in any stored energy system that doesn't have very high efficiency (>95%) in at least one half of the process or very much better than normal efficiency in both.

Super capacitor charge/discharge cycle (regeneative braking) generator 90% inverter 95% charge 95% discharge 95% inverter 95% motor 90% =100 x 0.9 x 0.95 x 0.95 x 0.95 x 0.95 x 0.9 =73% overall.

BEV using LiPoly batteries at 85% in place of supercaps. =100 x 0.9 x 0.95 x 0.85 x 0.85 x 0.95 x 0.9 = 52.8% overall.

These are both effective and sufficiently close to being viable on cost that they are being actively developed by major makers/suppliers.

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Reply to
Peter Hill

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