The car of the future: compressed air

Transport and new transport: energy, pollution, engine innovations, concept car, hybrid vehicles, prototypes, pollution control, emission standards, tax. not individual transport modes: transport, organization, carsharing or carpooling. Transport without or with less oil.
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I Citro
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by I Citro » 10/11/10, 09:42

We will see when the vehicles will be marketed, and if they are accessible to the general public and at what price ...
Which still raises a lot of questions ...
Obamot wrote:... but the air that comes out of these engines in town is cleaner than the ambient air! : Cheesy: :P : Mrgreen:
This is one of Guy Nègre's great arguments ... It remains to confront him with reality ...
Regarding the noise of his engines, he is careful not to talk about it, on the other hand ...
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Cuicui
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by Cuicui » 10/11/10, 10:05

There was a time when the air motor seemed to me the ideal solution. Replacing heavy, complex, fragile and polluting batteries with a simple, indestructible scrap tank seemed particularly attractive and ecological to me. It was only later that I understood the drawbacks of the process, in particular the release of heat during compression, and of cold during expansion, the danger of a pressurized tank in the event of an accident, the difficulty linked to the very high pressures necessary for ultimately disappointing autonomy ...
Damage.
Last edited by Cuicui the 10 / 11 / 10, 10: 22, 3 edited once.
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chatelot16
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by chatelot16 » 10/11/10, 10:05

the flow rate of a compressed-air engine is lower than a gasoline engine of the same power, and it does not heat up: it should not be too difficult to put a filter to collect the oil

in addition the lubricating oil is made to stick to the parts to be lubricated, it has no reason to be finely sprayed
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Gaston
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by Gaston » 10/11/10, 11:17

Cuicui wrote:There was a time when the air motor seemed to me the ideal solution.
Me too : Wink:

Cuicui wrote:It was only later that I understood the drawbacks of the process, in particular the release of heat during compression.
So if the compressor is powered by electricity, a compressed air vehicle consumes almost twice as much electricity per km as a battery vehicle :?
The gain in consumption obtained by making the vehicle lighter (replacing the batteries with an air tank) does not fully compensate for this difference. :(
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bernardd
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by bernardd » 10/11/10, 11:24

citro wrote:Regarding the noise of his engines, he is careful not to talk about it, on the other hand ...


The expansion noise at the outlet is the counterpart of a residual pressure, therefore of an efficiency margin to be improved.

On the videos, we hardly hear anything anymore: we will also have to add noise, because it's too quiet for pedestrians?

When the oil is ejected into the air, with the natural cooling of the engine, there should not be much left, because the air does not come out at high speed either given the low flow.

The engines are in normal technology ie metallic, but we also know that at low temperature, it will be possible one day to use ceramics, with extremely low friction.

What prevents the use of ceramics today are mechanical and thermal shocks in internal combustion engines.

They are used on the bearings of racing bikes, for example:
http://www.rouesartisanales.com/article-1069980.html
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by bernardd » 10/11/10, 11:41

Cuicui wrote:a simple hard-wearing scrap tank

Cuicui wrote:the danger of a pressurized tank in the event of an accident,


Are you bringing out the great myth for Halloween?

On a mobile, the tank is made of composite, lighter and with behavior without fragmentation in the event of an impact.

The danger is only an overpressure, with release of cold.

Firefighters go into burning buildings with a 300 bar bottle on their backs ...

With a battery, you have both overpressure et combustion.

And with a gasoline car, aren't you afraid of it? I saw a space burn on the ring road, nothing was left in less than 2 minutes, and I'm not even talking about a gasoline truck stuck in a traffic jam on the ring road ...

Cuicui wrote:in particular the release of heat during compression,


You're only talking about volume compression, and the usual technologies, for which energy efficiency is the least of the concerns.

There is a huge field of optimization, since it is possible to achieve 90% efficiency:
http://www.sustainx.com/isothermal_cycling.html

This is all the difference with a heat engine: the theoretical limit of the Carnot cycle is impassable !

And if you compress at home, the heat is recovered in the room thus heated, it is no longer a loss.

Cuicui wrote: and cold when relaxing,


On the contrary, it is an advantage, it means that the engine uses ambient thermal energy, thus putting the theoretical limit of the engine energy efficiency at 230% for the Airpod engine ...

And you can cool the vehicle in summer.

Cuicui wrote: the difficulty linked to the very high pressures necessary for ultimately disappointing autonomy ...


There is no particular difficulty, the 200 or 300 bars, it is well known for diving or firefighters.

As for autonomy, how would it be disappointing?
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bernardd
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by bernardd » 10/11/10, 11:43

Gaston wrote:So if the compressor is powered by electricity, a compressed air vehicle consumes almost twice as much electricity per km as a battery vehicle


Why spread rumors? What figures are you using to say that?
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Gaston
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by Gaston » 10/11/10, 11:49

bernardd wrote:Why spread rumors? What figures are you using to say that?
I do not know of any high pressure compressor whose efficiency exceeds 50%.
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Cuicui
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by Cuicui » 10/11/10, 11:52

bernardd wrote:And with a gasoline car, aren't you afraid of it?
If you compress at home, the heat is recovered in the room thus heated, it is no longer a loss.
The engine uses ambient thermal energy, thus putting the theoretical limit of engine energy efficiency at 230% for the Airpod engine ...
The vehicle can be cooled in summer.
As for autonomy, how would it be disappointing?

Since the engine of my petrol BX caught fire due to a hose leak, (luckily I was next to a fountain), I only drive in diesel ...
Heat and cold recovery: a good idea, indeed. I did not think about it.
Guy Nègre's vehicles had until now a very reduced range. Could you inform us of the progress made in this area?
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bernardd
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by bernardd » 10/11/10, 12:03

Gaston wrote:
bernardd wrote:Why spread rumors? What figures are you using to say that?
I do not know of any high pressure compressor whose efficiency exceeds 50%.


Ask for example http://www.bch-compresseurs.fr/produits ... alogue.php they have a water-cooled range which is at 60% energy efficiency (efficiency is another thing in thermodynamics ...).

And hot water at 40 ° can be used elsewhere.

But it is at low pressures that the efficiency is worst, without anyone really understanding why ...

It is also a sign that manufacturers have not really worked on efficiency.

By going down from 20 ° C to 0 ° C for example, we gain 7%, but no manufacturer has tested lower to my knowledge, at least for consumer products.

With a hydraulic compressor, EnAirys is increased to more than 80% with a cycle efficiency between 60 and 70% (0,6 = 0,8 x 0,8 ...). Their 10kW power prototype will run at 70% of production cycle.

And SustainX claims more than 80% over the cycle, up to 90%: 0,8 = 0,9 x 0,9! And that's for massive storage.
http://www.sustainx.com/isothermal_cycling.html
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