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'[OT]: Air car'
2002\08\22@091325 by Diego Sierra

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Hi!

Is this true?

http://www.theaircar.com/

Cheers,
Diego.

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2002\08\22@105751 by Mike Mansheim

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> Is this true?

> http://www.theaircar.com/

If it is, I don't know that I would consider it "safe" to be sitting
on a 4000+ psi container of compressed air in an accident.

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2002\08\22@122201 by Brendan Moran

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> Hi!
>
> Is this true?
>
> http://www.theaircar.com/
>
It looks plausible, though the question of safety under crash
situations should be foremost in peoples' minds.

- --Brendan

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2002\08\22@131938 by Dave King

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At 09:21 AM 22/08/02 -0700, you wrote:
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA1
>
> > Hi!
> >
> > Is this true?
> >
> > http://www.theaircar.com/
> >
>It looks plausible, though the question of safety under crash
>situations should be foremost in peoples' minds.
>
>- --Brendan

Natural gas or propane powered vehicle have been around for a long time.
Most city or post vehicles here are powered by it. They have a fairly safe
track record considering they also used compressed gas/liquid which rather
easily forms a nice combustible mixture. Compressed air should be safer
if they do it right.

Dave

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2002\08\22@132153 by Nelson Hochberg
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It's a bunch of bull.

Using their own figures:

90m3 storage / (566 cm3 x 4 cylinders x 3500 rpm) = 11.4 minutes running
time with no losses computed.
Hard to go 300km in less than 110km/h in 11.4 minutes.

Of course they are hinting that they get additional energy from hot air (In
the engine, atmospheric air is compressed to 20 Bar by the piston and heated
in the process to 400ºC.)  This seems absolutely true although the hot air
is not created by the engine.

Diego, if you choose to invest with them, let me know if you become rich and
I will apologize for my error.

Nelson

{Original Message removed}

2002\08\22@132418 by Justin Grimm

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I've seen a piece of rhs explode at 3000psi, it aint a pretty sight.
What pressure do the gas cars run at?

Justin G

{Original Message removed}

2002\08\22@154657 by Magnus von Rosen

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> > Is this true?
>
> > http://www.theaircar.com/

There was a short article about it in the big Swedish car magazine after a
press show in Stockholm. A blonde beauty was bragging about all the benefits
(the authors of the article showed no mercy in describing her talents) such
as travelling 300km in 130 kmh, and just popping into the gas station for a
quick air refill using the tire refill hose/thingie.

The journalists quickly asked if it could really travel that far at that
high speed. The blonde beaty did not know. It turned out to of course only
driving 8 km or something at 130 kmh. And of course, the pressure of a
normal tire pump at a gas station is by far too low (3-4 bar) to do any good
when pumping up the car.

The electrical charging is done with a charger in classical Wall-Wart style,
extremely flimsy and ridicilous. The Wall-Wart drives a small pump-motor.
The tests made by the reporters showed that it took considerably longer to
charge the car, than the few hours stated in the specs. More like three
times that, if I rembember correctly.
One wonders why they don't install a high power compressor. If it could pump
up in 10 minutes, the car would be worth something!

The article also questioned the safety of the car with the high pressure
tank.

Regards
Magnus von Rosen, Sweden
{Original Message removed}

2002\08\22@172139 by Diego Sierra

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Hi!

> Natural gas or propane powered vehicle have been around for a long time.
>[...]
> easily forms a nice combustible mixture. Compressed air should be safer
> if they do it right.

Yes, the thing here is that there is neither combustible nor combustion at
all.

Cheers,
Diego.

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2002\08\22@172507 by Diego Sierra

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>Diego, if you choose to invest with them, let me know if you become rich
and

Oh, no!, I am just wondering to buy one ;-)

First I thought it was one of those fake web sites that only tell lies.

Cheers,
Diego.

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2002\08\22@191353 by Russell McMahon

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> > Is this true?
>
> > http://www.theaircar.com/

Not in the combination they mention.
The maximum possible energy storage capability is very very low compared
with any sort of combustion engine.

The peak speed claimed MAY be achievable - that would require about 5 kW on
a VERY well streamlined body but the range would then be small.

The range MAY be achievable at very very low speeds (say 10 to 30 kph range)
on a flat track in ideal conditions. Energy consumption of a well designed
vehicle approaches zero per km as speed approaches zero :-)

The cost of 1 cent a kilometre suggests 300 km x 1 cent = 300 cents = about
30 kWH energy. Even allowing for heat loss while compressing (see gas laws)
there is no way to store anything approaching that much compression energy
in  car that size even with liquid air. Even if it was, 300 km at 50 kph = 6
hours. 30 kWH/6 = 5 kW average energy. Quite apart from the inability to
travel at that speed in real conditions, how would you like to drive a car
in traffic with a mean power of 5 kW / 7 HP ? :-)

Roughly, Energy available (after heat losses during compression) = Volume x
Patmospheric x ln(Pmax/Patmos)  (and getting this out again from a high
pressure source requires a very clever motor). A rough calculation shows
that most people will be disappointed if they rely on the brochure figures.



       Russell McMahon

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2002\08\22@202241 by Peter L. Peres

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On Thu, 22 Aug 2002, Magnus von Rosen wrote:

>One wonders why they don't install a high power compressor. If it could pump
>up in 10 minutes, the car would be worth something!

Because it would have to be far too powerfull. You want to put in in 10
minutes the energy you get out in 1 hour. Then you want about six times
the motor power (neglecting losses). A small car will have 20+kW (is
20hp), so you want 20*6=120kW. That would be a rather large wall wart I
think, even if you don't have to remove the heat from the compressed air
(but you have to or bad things will happen).

Peter

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2002\08\23@032412 by Diego Sierra

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Hi!

About some of the things we talk here, a friend of mine (which read the
quotes) said:

> If it is, I don't know that I would consider it "safe" to be sitting
> on a 4000+ psi container of compressed air in an accident.

4K psi is the pressure of the bottle he uses for scuba diving, and he
doesn't know about an accident with them so far. "Is worse to sit over 50
liters of gasoline, isn't it ?".

>90m3 storage / (566 cm3 x 4 cylinders x 3500 rpm) = 11.4 minutes running
>time with no losses computed.

They didn't say how much of the stored (compressed) air is used when
injected into the cylinders.

Cheers,
Diego.

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2002\08\23@042845 by Richard Stevens

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Here are some more thoughts.  For reasons of ongoing personal stupidity they
all avoid gas dynamics....
You recharge the thing by plugging it in at home for four hours. The max
power you can get from a standard domestic outlet is about 3kw. (230V 13A.
That's how it is in this part of the world, I doubt it is orders of
magnitude different elsewhere).
If recharging takes 4 hours then the total energy in to the system is 3000 x
60 x 60 x 4 = about 43MJ.   That is about the same amount of energy as in
1Kg of gasoline.
To be fair, only about 20 - 25 % of the energy in gasoline is recoverable in
a IC engine, so we can say that the air car, fully charged, has the energy
equivalent of 1 gallon of gasoline on board.

190 mpg (300km/..) at moderate speeds in a superlight vehicle is not
stretching the credibility envelope too far. Don't forget the mileages
achived in competitions like the shell mileale marathon (>1000mpg,
admittedly in super specials)

Looking at my latest electricity bill, I see that the cost of night time
electricity is around 4.5 pence / Kw/h. So my gallon equivalent cost me 3 x
4 x 4.5 = 54 pence.
My gallon of gasoline would have cost me 3.30 GBP - 6 times as much.

So, if I was happy to drive a low powered vehicle at moderate speeds for
less than 300 km, i could save myself some money, and do my conscience a lot
of good.

This could have the edge on electric vehicles too, as storage will not
degrade over time and there will be no batteries to periodically replace /
dispose of.

Richard


{Original Message removed}

2002\08\23@044351 by Also-Antal Csaba

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> Natural gas or propane powered vehicle have been around for a long time.

The pb gas will be liquid on 16bar presure, this can be store on plastic
tank.
The cng is other thing. That not change to liquid state at (~) low
presure, that stored on composit made tank (at least in hungary) with
200bar presure. Its very dangerous, this used only in long ranges buses,
trucks and the tank is placed on the rof of the bus.


udv
Csaba

Ps:
During the ww2 my grandfather have a nice car, but no fuel for this.
With his brother build a wood gas reactor from old oil tank and some
pipe :))))

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2002\08\23@052644 by Jinx

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> Ps:
> During the ww2 my grandfather have a nice car, but no fuel
> for this.With his brother build a wood gas reactor from old
> oil tank and some pipe :))))

In the UK in WW2 cars also had a bag on the roof. I think it was
filled with town gas (coal gas ? from coke-making. That's coke,
not Coke. Coke produces cola gas)

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2002\08\23@053953 by Katinka Mills

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> -----Original Message-----
> From: pic microcontroller discussion list
> [.....PICLISTKILLspamspam.....MITVMA.MIT.EDU]On Behalf Of Jinx
> Sent: Friday, 23 August 2002 5:26 PM
> To: EraseMEPICLISTspam_OUTspamTakeThisOuTMITVMA.MIT.EDU
> Subject: Re: [OT]: Air car
>
>
> > Ps:
> > During the ww2 my grandfather have a nice car, but no fuel
> > for this.With his brother build a wood gas reactor from old
> > oil tank and some pipe :))))
>
> In the UK in WW2 cars also had a bag on the roof. I think it was
> filled with town gas (coal gas ? from coke-making. That's coke,
> not Coke. Coke produces cola gas)

Should that not be Coke produces Colon gas ? ;o)

Regards,

Kat.

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2002\08\23@054804 by Jinx

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> > In the UK in WW2 cars also had a bag on the roof. I think it was
> > filled with town gas (coal gas ? from coke-making. That's coke,
> > not Coke. Coke produces cola gas)
>
> Should that not be Coke produces Colon gas ? ;o)

Or if you've had a stomach bypass, semicolon gas

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2002\08\23@060502 by tony

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Or if you've had a stomach bypass, semicolon gas

LOL VERY LOUDLY

1000 points although the points don't matter
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2002\08\23@071512 by Jinx

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> Or if you've had a stomach bypass, semicolon gas
>
> LOL VERY LOUDLY
>
> 1000 points although the points don't matter

Yup, that's right, the points don't matter. Just like Piclist
"how to unsubscribe" instructions

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2002\08\23@074228 by Alan B. Pearce

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>> Is this true?

>> http://www.theaircar.com/

>If it is, I don't know that I would consider it "safe" to be sitting
>on a 4000+ psi container of compressed air in an accident.

Well I guess it would be safer than an LPG cylinder.  I do not know what
pressure the LPG is stored at, but it must be something pretty reasonable to
keep it liquid, instead of turning to CNG. CNG and LPG both get used in
motor vehicles out on the highway.

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2002\08\23@075324 by tony

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Yup, that's right, the points don't matter. Just like Piclist
"how to unsubscribe" instructions

Hi Jinx

With all the development that you do, do you
have time to watch  Drew Carrey  "Whose line is it anyway" --

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2002\08\23@075720 by Alan B. Pearce

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>During the ww2 my grandfather have a nice car, but no
>fuel for this. With his brother build a wood gas reactor
>from old oil tank and some pipe :))))

This was also done in the UK during the war. Anyone who has watched the TV
series "Dads Army" will have seen the gas bag on to of Corporal Jones truck
in the episodes where they go driving. In one episode I seem to remember
this inflating to a point where it (supposedly) lifted the truck off the
ground, but I could be wrong about this.

Also if you go to the Steam Train Museum at Nordlingen in Germany, you can
see a locomotive with this wood gas reactor equipment, and collection tanks
on it :)

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2002\08\23@082713 by Jinx

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> With all the development that you do, do you have time to
> watch  Drew Carrey  "Whose line is it anyway" --

Always got time for Ryan Stiles and Colin Mochrie

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2002\08\23@100425 by Michael Rigby-Jones

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> -----Original Message-----
> From: Alan B. Pearce [SMTP:RemoveMEA.B.Pearcespam_OUTspamKILLspamRL.AC.UK]
> Sent: Friday, August 23, 2002 12:40 PM
> To:   RemoveMEPICLISTTakeThisOuTspamspamMITVMA.MIT.EDU
> Subject:      Re: [OT]: Air car
>
> >> Is this true?
>
> >> http://www.theaircar.com/
>
> >If it is, I don't know that I would consider it "safe" to be sitting
> >on a 4000+ psi container of compressed air in an accident.
>
> Well I guess it would be safer than an LPG cylinder.  I do not know what
> pressure the LPG is stored at, but it must be something pretty reasonable
> to
> keep it liquid, instead of turning to CNG. CNG and LPG both get used in
> motor vehicles out on the highway.
>
At 100F, propane has a vapour pressure of only 205PSI.

Regards

Mike

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2002\08\23@100848 by Also-Antal Csaba

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Jinx wrote:
>
> > Ps:
> > During the ww2 my grandfather have a nice car, but no fuel
> > for this.With his brother build a wood gas reactor from old
> > oil tank and some pipe :))))
>
> In the UK in WW2 cars also had a bag on the roof. I think it was
> filled with town gas (coal gas ? from coke-making. That's coke,
> not Coke. Coke produces cola gas)

This not filed, this produce the (I think carbon monoxid) gas. They put
in some wood to the barell and strike fire. Then close the lid and the
slow oxigen-poor burning produce co gas.

udv
Csaba

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2002\08\23@105424 by Shawn Mulligan

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>Always got time for Ryan Stiles and Colin Mochrie
>
Ah yes. The great Canadian Colin Mochrie! -Shawn




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2002\08\23@122547 by Brendan Moran

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> >Always got time for Ryan Stiles and Colin Mochrie
> >
> Ah yes. The great Canadian Colin Mochrie! -Shawn

So, the question is... Who is Colin, and why is this guy mocking him?

--Brendan

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2002\08\23@195018 by Jinx

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> > >Always got time for Ryan Stiles and Colin Mochrie
> > >
> > Ah yes. The great Canadian Colin Mochrie! -Shawn
>
> So, the question is... Who is Colin, and why is this guy
> mocking him?

Mr Mochrie is a man who knows how to pronounce his first
name correctly, unlike the Secretary Of State for a certain
country to the south of Canada. Funny how things go full
circle - we're back to colons again

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2002\08\23@200124 by Brendan Moran

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> > > >Always got time for Ryan Stiles and Colin Mochrie
> > > >
> > > Ah yes. The great Canadian Colin Mochrie! -Shawn
> >
> > So, the question is... Who is Colin, and why is this guy
> > mocking him?
>
> Mr Mochrie is a man who knows how to pronounce his first
> name correctly, unlike the Secretary Of State for a certain
> country to the south of Canada. Funny how things go full
> circle - we're back to colons again

I should have something really clever to say in response to that, but ATM, I
just can't come up with one... :(

--Brendan

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2002\08\23@201138 by Dave King

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At 04:59 PM 23/08/02 -0700, you wrote:
> > > > >Always got time for Ryan Stiles and Colin Mochrie
> > > > >
> > > > Ah yes. The great Canadian Colin Mochrie! -Shawn
> > >
> > > So, the question is... Who is Colin, and why is this guy
> > > mocking him?
> >
> > Mr Mochrie is a man who knows how to pronounce his first
> > name correctly, unlike the Secretary Of State for a certain
> > country to the south of Canada. Funny how things go full
> > circle - we're back to colons again
>
>I should have something really clever to say in response to that, but ATM, I
>just can't come up with one... :(
>
>--Brendan

Don't worry Brendan I'm sure you'll figure out something in the "end"....

Dave ;-]

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2002\08\23@202229 by Brendan Moran

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> > > > > >Always got time for Ryan Stiles and Colin Mochrie
> > > > > >
> > > > > Ah yes. The great Canadian Colin Mochrie! -Shawn
> > > >
> > > > So, the question is... Who is Colin, and why is this guy
> > > > mocking him?
> > >
> > > Mr Mochrie is a man who knows how to pronounce his first
> > > name correctly, unlike the Secretary Of State for a certain
> > > country to the south of Canada. Funny how things go full
> > > circle - we're back to colons again
> >
> >I should have something really clever to say in response to that, but
ATM, I
> >just can't come up with one... :(
> >
> >--Brendan
>
> Don't worry Brendan I'm sure you'll figure out something in the "end"....

Maybe all I need to do is *back*track a bit, and a little to the *side* ;)

--Brendan

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2002\08\23@212332 by Jinx

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> > country to the south of Canada. Funny how things go full
> > circle - we're back to colons again
>
> I should have something really clever to say in response to that,
> but ATM, I just can't come up with one... :(

I'm sure you could work something out with a pencil and
piece of paper

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2002\08\24@070123 by Peter L. Peres

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Ok, I found a formula for the power in compressed air.

Pair [W] = Qv [m^3/sec] * Press [kgf/m^2]

300bar is ~3x10^6 kgf/m^2

Assuming you need 10hp to move the car at about half the max. speed (for
max. efficiency) you need 8kW for 6 hours (300km at 55km/h, half the max.
speed). That's 21600 seconds. Assuming 20bar equivalent pressure in the
motor (I just picked that number for reasonable end pressure in the tank -
20 bars is about ten times the pressure in a usual shop air end hose and a
usual working pressure in many pneumatic circuits):

Qv = Pair [W] / Press [kgf/m^2] = 8000/204000 = 0.04 [m^3/sec]

for 21600 seconds:

V = 864 [m^3]

which at 300 bars (15 times more than 20bars) are:

V1 = 57.6 [m^3]

which is less than their 90m^3 tank and very credible because I assumed
100% efficiency and theirs is lower, about 64% (based on the ratio of
their tank volume and V1 above).

There would be the small problem of keeping the whole thing from
*freezing* stiff, this requires about 6-7kW of heat *input* while working
(remember expanding gas cools it down). This is what they use the
compression of atmospheric air for I think.

Recharging the thing would require the same energy input (assuming 100%
efficiency as above but with their tank volume). Eg 6-8kW for 12 hours,
probably more like 6-8kW for 14-18hours to account for efficiency. 300bar
compressors do not grow on trees so I suppose it comes with the car (maybe
the motor is reversible and they have an electric motor to drive it).

Guy Negre was a F1 mechanic in a previous life I think, and he must know
what he is doing.

I liked the idea of soy oil lubrication ;-).

Peter

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2002\08\24@100713 by Russell McMahon

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> Ok, I found a formula for the power in compressed air.
> Pair [W] = Qv [m^3/sec] * Press [kgf/m^2]
> 300bar is ~3x10^6 kgf/m^2

Your calculations are probably approximately correct BUT they rely on a
statement by the manufacturer that was accidentally misleading AND there is
a need to alter your formula to account for the practical situation.

Firstly, the stated tank volume of 90 m^3 was (probably) intended as the
volume of gas at ambient after expansion (or before compression). The real
tank volume is less than a cubic metre. (Note the size of the car itself is
probably in the order of 5 cubic metres. They correct this error somewhere
on their site (in the FAQ?). For the E=QP formula to apply the pressure used
must be maintained throughout the "work stroke" represented here by the
Volume. (You use m^3/sec which is the instantaneous power but if you take
total volume and remove the time term you get total available energy).

Secondly, if you have a cylinder with a piston in it and you apply the
maximum pressure and the piston moves by the volume stated then the work
done would be equal to QP as you state.

This is a restatement of the well known formula

       work = force x distance.

Here volume = area x stroke.
Force = area x pressure
So work = Volume x pressure = area x stroke x pressure
= force x stroke
= force x distance.

With a gas, when you compress it from Pambient to Pmax then the average or
effective pressure is related to the natural logarithm (ln) of the pressure
ratios. For example if I compress air from 1 bar to 10 bar the effective
pressure is ln(10/1) = 2.3. ie the average pressure is 2.3 bar. This makes
sense if you consider the pressure on the piston as it moves down the
cylinder. After it has moved 50% of the way the pressure has double. After
it has moved 75% of the way the pressure has risen by 4 times. The maximum
pressure occurs only at the very end.

So, if you increase pressure from 1 bar to 300 bar the EFFECTIVE pressure =
ln(300)
BUT ln(300) ~= 6 !!!
A 300 bar "charge" expanding to ambient will only provide a MEAN pressure of
about 6 bar. This astounding result again makes sense when you look at the
pressure in the cylinder as you expand it.
Take a cylinder of 299 units volume and a "head" space of 1 unit volume. At
full expansion you have 300 units. At full compression you have 1 unit. Now
make it a 300 unit cylinder to make the sums very slightly easier.

Now start expansion.
At zero stroke you have 300 bar. At 1/300th of the stroke you are down to
150 bar (already) as volume has doubled. At 2/300 of stroke it's 100 bar. At
3/300 or 1% of stroke its 75 bar. And so it goes on. At 50% of stroke
pressure is about 2 bar ! You need a very special expansion engine to handle
such wide expansion ratios efficiently.

It actually gets worse. Intuitively we may feel that P1V1 = P2V2.
Unfortunately the gas laws state
PV^gamma = constant.
(Gamma is the specific heat of the gas at constant pressure compared to that
at constant volume).
For a perfect gas (and air is close enough) gamma = 1.414 ( = root two).
This reflects the equal division of energy between l=kinetic and potential
energies - heat and pressure. In most cases the heat of compression is lost.
Real thermodynamicists may wish to put on hobnail boots and take task with
how I have described this but the principles are essentially as stated.

Nice online tutorial in fluid dynamics here


http://www.cfdrl.uc.edu/WebPage/Courses/comp_flow/cf_index.html


The outcome of all this is that the available power is far less than it may
have appeared. Recalculating to see how little may leave you surprised.




       Russell McMahon







{Quote hidden}

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2002\08\24@114248 by Roman Black

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Russell McMahon wrote:

> Now start expansion.
> At zero stroke you have 300 bar. At 1/300th of the stroke you are down to
> 150 bar (already) as volume has doubled. At 2/300 of stroke it's 100 bar. At
> 3/300 or 1% of stroke its 75 bar. And so it goes on. At 50% of stroke
> pressure is about 2 bar ! You need a very special expansion engine to handle
> such wide expansion ratios efficiently.


Which is why turbines etc have rotors of differing
sizes as the gas reaches lower pressures and higher
velocities. Did they specifically say that the car
was piston powered?

A properly designed turbine may have other advantages,
ie; flywheel effect, which has already been considered
for electric vehicle use as it can give a bit of
"oomph" to a paltry 6kW average vehicle.

Slightly OT, but I once saw an "economy marathon" type
vehicle with variable-diameter flywheel, so energy could
be fed into it (or drawn out like a spinning ballerina)
-Roman

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2002\08\24@121447 by Peter L. Peres

picon face
On Sun, 25 Aug 2002, Russell McMahon wrote:

>> Ok, I found a formula for the power in compressed air.
>> Pair [W] = Qv [m^3/sec] * Press [kgf/m^2]
>> 300bar is ~3x10^6 kgf/m^2
>
>Your calculations are probably approximately correct BUT they rely on a
>statement by the manufacturer that was accidentally misleading AND there is
>a need to alter your formula to account for the practical situation.
>
>Firstly, the stated tank volume of 90 m^3 was (probably) intended as the
>volume of gas at ambient after expansion (or before compression). The real
>tank volume is less than a cubic metre. (Note the size of the car itself is
>probably in the order of 5 cubic metres. They correct this error somewhere
>on their site (in the FAQ?). For the E=QP formula to apply the pressure used
>must be maintained throughout the "work stroke" represented here by the
>Volume. (You use m^3/sec which is the instantaneous power but if you take
>total volume and remove the time term you get total available energy).

I know, I deliberately tried to calculate for the max. available energy,
with some shortcuts.

I missed the car volume (5m^3) vs tank volume (90m^3). The messages about
gas bags on top of cars suddenly make sense ;-)

Peter

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2002\08\24@141845 by Peter L. Peres

picon face
On Sun, 25 Aug 2002, Roman Black wrote:

>Russell McMahon wrote:
>
>> Now start expansion.
>> At zero stroke you have 300 bar. At 1/300th of the stroke you are down to
>> 150 bar (already) as volume has doubled. At 2/300 of stroke it's 100 bar. At
>> 3/300 or 1% of stroke its 75 bar. And so it goes on. At 50% of stroke
>> pressure is about 2 bar ! You need a very special expansion engine to handle
>> such wide expansion ratios efficiently.

>Which is why turbines etc have rotors of differing
>sizes as the gas reaches lower pressures and higher
>velocities. Did they specifically say that the car
>was piston powered?

Yes. Go read at their webpage.

>A properly designed turbine may have other advantages,
>ie; flywheel effect, which has already been considered
>for electric vehicle use as it can give a bit of
>"oomph" to a paltry 6kW average vehicle.

>Slightly OT, but I once saw an "economy marathon" type
>vehicle with variable-diameter flywheel, so energy could
>be fed into it (or drawn out like a spinning ballerina)

You mean the wheel had constant rpm and changed the interial moment by
physically changing the diameter of the moving part ? Clever but I suspect
'some' mechanical troubles. It could be done with liquid, pumping it in
and out at the hub to change Mi. The centrifugal force would keep it glued
to the circumference (on the inside of a hollow wheel). There would be
interesting things happening if the wheel would not be horzontal. Even a
h. wheel would do interesting things. Imagine driving into a pothole on
the right front and the car tilting left instead of falling in ...

You'd need two wheels mounted rigidly and counter-rotating to cancel these
effects. Double trouble.

Peter

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2002\08\24@142110 by Quentin

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>Guy Negre was a F1 mechanic in a previous life I think, and he must know
>what he is doing.
Prolly was pumping the tyres...
;)
Quentin
TakeThisOuTqscspamspamiptech.co.za
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2002\08\24@142926 by Nelson Hochberg

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So when you get all done, the endurance of the air car would be less than
ten minutes.  Sort of like the plastic toy cars with balloons on top that
you blow up and they shoot across the floor -- only bigger (and a lot more
expensive.)

{Quote hidden}

used
>must be maintained throughout the "work stroke" represented here by the
>Volume. (You use m^3/sec which is the instantaneous power but if you take
>total volume and remove the time term you get total available energy).

I know, I deliberately tried to calculate for the max. available energy,
with some shortcuts.

I missed the car volume (5m^3) vs tank volume (90m^3). The messages about
gas bags on top of cars suddenly make sense ;-)

Peter

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2002\08\24@151940 by Peter L. Peres

picon face
On Sat, 24 Aug 2002, Quentin wrote:

>>Guy Negre was a F1 mechanic in a previous life I think, and he must know
>>what he is doing.
>Prolly was pumping the tyres...
>;)
>Quentin

I am about as sure of the PR 'technical data' on the site not being his
doing, as I am sure that he knows his stuff.

Peter

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2002\08\24@153811 by Roman Black

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Peter L. Peres wrote:

> >Slightly OT, but I once saw an "economy marathon" type
> >vehicle with variable-diameter flywheel, so energy could
> >be fed into it (or drawn out like a spinning ballerina)
>
> You mean the wheel had constant rpm and changed the interial moment by
> physically changing the diameter of the moving part ? Clever but I suspect
> 'some' mechanical troubles. It could be done with liquid, pumping it in
> and out at the hub to change Mi. The centrifugal force would keep it glued
> to the circumference (on the inside of a hollow wheel).

From memory it had pivoting weights similar to
the system used for ignition advance weights in
older cars. A slipring and cable (or similar) were
used to "open" or "close" the wheel size when
running so the vehicle could feed some energy back
into movement for hills and soak it up on the
downhills. It was only a tiny one-man thing.
I suppose it's just a way of getting energy out
of a flywheel without doing much. :o)
-Roman

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2002\08\25@142340 by Peter L. Peres

picon face
On Sun, 25 Aug 2002, Roman Black wrote:

{Quote hidden}

The only problem being that Wi = I * omega^2 where omega is the rpm
expressed in rads/sec afair. So changing I would be quadratic unless you
are tapping a very small amount of energy wrt the total. Then why bother ?

Peter

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2002\08\26@185703 by Brendan Moran

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This is a parallel post of the [OT]: Gas and Taxes thread

http://www.toyota.com/html/shop/vehicles/ravev/rav4ev_0_home/index.html

"In addition to generating zero emissions, the revolutionary 67-hp motor is
capable of approaching 78 mph, more than adequate for both street and
highway driving."

"Utilizing 24 high-capacity, nickel-metal hydride batteries, the RAV4 can
travel up to 126 miles on a single charge. For most of us, that's enough to
get us to work and back.*"

"*Actual range will vary depending on your driving habits."

Say goodbye, aircar.

--Brendan

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2002\08\26@203843 by hard Prosser

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Interesting - they claim that the batteries should be replaced after
100,000 miles. (Due to wear & Tear)
Also -  "There is currently no charge for using the roadside charging
facilities"  - just a "get you home boost" or free motoring?

Richard P



This is a parallel post of the [OT]: Gas and Taxes thread

http://www.toyota.com/html/shop/vehicles/ravev/rav4ev_0_home/index.html

"In addition to generating zero emissions, the revolutionary 67-hp motor is
capable of approaching 78 mph, more than adequate for both street and
highway driving."

"Utilizing 24 high-capacity, nickel-metal hydride batteries, the RAV4 can
travel up to 126 miles on a single charge. For most of us, that's enough to
get us to work and back.*"

"*Actual range will vary depending on your driving habits."

Say goodbye, aircar.

--Brendan

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2002\08\26@213053 by Andrew Warren

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Richard Prosser <spamBeGonePICLISTEraseMEspammitvma.mit.edu> wrote:

> Also -  "There is currently no charge for using the roadside
> charging facilities"  - just a "get you home boost" or free
> motoring?

   Sounds like free long-distance telephony using digitized voice
   over your "free" internet connection, which Bob Metcalfe once
   likened to the free heating you could get by stealing rolls of
   toilet tissue from public restrooms and burning them in your
   furnace.

   In other words, it'll be free while no one's using it, but I
   wouldn't expect it to stay that way.

   -Andy

=== Andrew Warren -- aiwspamBeGonespamcypress.com
=== Principal Design Engineer
=== Cypress Semiconductor Corporation
===
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation

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2002\08\27@045312 by Russell McMahon

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Toyota RAV4e electric.

http://www.toyota.com/html/shop/vehicles/ravev/rav4ev_0_home/index.html


> "In addition to generating zero emissions, the revolutionary 67-hp motor
> is capable of approaching 78 mph, more than adequate for both street
> and highway driving."

67 HP (= suspiciously close to 50 kW.)
Suggesting a rather high power capability battery.

> "Utilizing 24 high-capacity, nickel-metal hydride batteries,

Spec page says 24 x 12v batteries (!)
Onboard charger rated at 30A x 220v and takes 7.5 hours
30 x 220 x 7.5 = 50 kWH
Allow inefficiency losses in charger and battery storage to give about 40
kWH energy storage.

40,000 / 12v / 24 batteries ~= 140 AH batteries. That's about 3 times the
capacity of a typical car battery. Even allowing for the superior capacity
of NiMH that's a top spec battery.

Pretend max range available at 30 mph so time = 126 miles /30 = 4 hours or
so.
(Note that 126 miles is suspiciously close to 200 km :-) )

40 kWH/4 = 10 kW ~= 13 HP average. Not vast and much less than the 67 HP
peak.

50 kW peak power /12v/24 =~ 175A peak - entirely believable.
(Batteries will not all be  in series almost certainly but sums work out the
same.)

100,000 mile battery life.
100000/126 miles per charge =~ 800 charges = about 2 years

> Say goodbye, aircar.

How much will 24 x 12v x 130 AH NiMH batteries cost?
I'd GUESS that a figure of $US200 per battery would be in the ballpark and
probably low - possibly very low. (A standard auto use battery half that
capacity in Lead Acid is $US40 ish trade here. Deep discharge and marine use
are far more. The NimH has to be very good at deep discharge.)

24 *$200/2 = $2400 per year or $6 per trip. Proportionately more if
batteries cost more.
126 miles @ $6 = 5c/mile or highly competitive with petrol (depending what
country you live in). On top of this there is a purchase incentive which I
think was $3000 pa for 3 years. May have read that wrong? Plus you get to
park in special car parks. Apparently battery disposal costs and energy
production at a distance are acceptable compared to smog.

I wonder how long the 100+ Californian recharge stations will continue to
give away 40 kWH = $4 charges for free?

Air cars may still have a place.
But, bureaucracy being what it is,  you probably wouldn't be allowed to park
one in spaces reserved for electric cars :-)



       Russell McMahon






>
> --Brendan
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2002\08\27@123619 by Brendan Moran

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>     Sounds like free long-distance telephony using digitized voice
>     over your "free" internet connection, which Bob Metcalfe once
>     likened to the free heating you could get by stealing rolls of
>     toilet tissue from public restrooms and burning them in your
>     furnace.

I'd say that Voice Over IP is here to stay.  Especially since you're already
paying for the data connection.  Once it's paid for, what data you send
where is your business.

--Brendan

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2002\08\27@142919 by Spehro Pefhany

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At 09:34 AM 8/27/02 -0700, you wrote:
>I'd say that Voice Over IP is here to stay.  Especially since you're already
>paying for the data connection.  Once it's paid for, what data you send
>where is your business.

OTOH, long distance rates are asymptotic to zero. Not that long ago, it
cost $60 an hour to call the Far East, now it costs more like $6. In that
time span, the amount I charge for an hour of my time has increased by
5:1 (and still a bargain, I might add). So, for me anyway, the cost of a
long distance call has gone down by 50:1.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
RemoveMEspeff@spam@spamspamBeGoneinterlog.com             Info for manufacturers: http://www.trexon.com
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2002\08\27@143258 by Peter L. Peres

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On Tue, 27 Aug 2002, Brendan Moran wrote:

>>     Sounds like free long-distance telephony using digitized voice
>>     over your "free" internet connection, which Bob Metcalfe once
>>     likened to the free heating you could get by stealing rolls of
>>     toilet tissue from public restrooms and burning them in your
>>     furnace.
>
>I'd say that Voice Over IP is here to stay.  Especially since you're already
>paying for the data connection.  Once it's paid for, what data you send
>where is your business.

You wish. Current pricing schemes are based on web surfing habits. If lots
of people talk a lot or use too much broadband they will charge more
and/or throttle. They are already doing both in most broadband places
afaik.

Peter

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2002\08\27@143915 by Spehro Pefhany

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At 09:29 PM 8/27/02 +0300, you wrote:

>You wish. Current pricing schemes are based on web surfing habits. If lots
>of people talk a lot or use too much broadband they will charge more
>and/or throttle. They are already doing both in most broadband places
>afaik.

Yes, they are starting to charge heavy users of broadband bandwidth
more money, BUT, voice over IP isn't going to be much of a bandwidth
user compared to downloading _Lord of the Rings_ as a VCD, or
filling your HDD with "shared" MP3's.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
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2002\08\27@152441 by Brendan Moran

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> >I'd say that Voice Over IP is here to stay.  Especially since you're
already
> >paying for the data connection.  Once it's paid for, what data you send
> >where is your business.
>
> You wish. Current pricing schemes are based on web surfing habits. If lots
> of people talk a lot or use too much broadband they will charge more
> and/or throttle. They are already doing both in most broadband places
> afaik.

Not really.  All they have is a packet and an IP, they don't know what it
is, and if your VOIP protocol is done properly, they will be unable to
figure it out.  All part of this little thing called privacy.

And as someone else mentioned, running Kazaa or Kazaa Lite (Or WinMx) will
take up roughly 10x that bandwidth.

--Brendan

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2002\08\27@155551 by Dale Botkin

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At work we have network connections between all of our offices.  VoIP is a
whole lot cheaper than maintaining separate T1 or DS3 voice lines or
paying long distance charges.

Dale
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Fusistance is retile.
Your ass will be laminated.

On Tue, 27 Aug 2002, Brendan Moran wrote:

> I'd say that Voice Over IP is here to stay.  Especially since you're already
> paying for the data connection.  Once it's paid for, what data you send
> where is your business.

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