Compressed air power car
russbost - 9/1/12 at 08:00 PM
Linky
I know this is a repost in that I can recall it being discussed ages ago, does anyone know if they ever got any further with this project?
Personally, my suspicions would be that it's died a death, due to
1. High cost of "refuelling" due to losses compressing air etc.
2. Lack of range due to low Wh storage capacity of the compressed air
& before anyone bothers to point it out, I'm well aware that currently it would effectively be running on fossil fuels, just moving the point
of usage back up the line to the power station, nevertheless i find it interesting & if we don't persue different lines of thought we'll
never move forward.
Anyone got any further info?
Paul_C - 9/1/12 at 08:28 PM
Hello,
It's been used for rail locomotives where other propulsion systems were unwanted or dangerous. There are some listed at
http://www.douglas-self.com/MUSEUM/LOCOLOCO/airloco/airloco.htm
My guess is lack of range is the problem though someone cleverer than I can calculate the energy storage of a tank.
designer - 9/1/12 at 08:33 PM
A french bloke made a compressed air car years ago, will see if I can find referance to it.
Could lack of range be cured by an engine driven compressor?
snapper - 9/1/12 at 08:38 PM
Scuba tanks can run 232 bar and come in upto 15 litre volume.
Some high tec carbon tanks run 300 bar but tend to be smaller in physical capacity
Now it depends on flow volume for how long the tanks last.
balidey - 9/1/12 at 08:40 PM
Personally I think steam is the answer, but generate superheated steam by an onboard microwave heater.
Batteries could be topped up by regenerative braking and then connected to the national grid at night.
steve m - 9/1/12 at 08:44 PM
What a load of hot air
Liam - 9/1/12 at 09:56 PM
quote:
Originally posted by designer
A french bloke made a compressed air car years ago, will see if I can find referance to it.
Could lack of range be cured by an engine driven compressor?
Errrr, but if you're gonna have an engine, just drive the wheels - much more efficient than compressing air. :p
hughpinder - 10/1/12 at 08:50 AM
I saw an article a few years ago about a french town that runs its busses on compressed air, provided by direct compression from a windmill - just
can't find the reference now. It used carbon fibre tanks. I'm guessing you get free aircon as the gas expands! While trying to find the
article, I found a reference that says compressed air at 300bar = 0.1Mj per litre of stored energy, so 40 litres approx 1 kWh.(1l of petrol/diesel is
about 12 to 13kWh, but you maximum efficiency of an engine is 40-55% depending on type). I suppose you could also have electric motors to store/use
the braking energy, and for busses in busy towns, you dont need to use any while stationary!
Regards
Hugh
designer - 10/1/12 at 10:06 AM
quote:
Errrr, but if you're gonna have an engine, just drive the wheels - much more efficient than compressing air. :p
Same principle, the Deltic, diesel generated electric train, very efficient for that eras technology.
Neville Jones - 10/1/12 at 02:29 PM
quote:
Originally posted by designer
quote:
Errrr, but if you're gonna have an engine, just drive the wheels - much more efficient than compressing air. :p
Same principle, the Deltic, diesel generated electric train, very efficient for that eras technology.
No different to the hybrids of today.
An internal combustion engine with an electric transmission.
Interestingly, hybrids don't have to pass emissions testing, don't even have to be tested.
Now, what sort of twisted thinking is that?
You can have the worst polluting ic engine driving a generator, driving the electric motors driving the wheels, and get away with it. Even be
congratulated for being 'green'. Put a gearbox and gears driving the wheels from the same engine, and it's a polluter!
Cheers,
Nev.
britishtrident - 10/1/12 at 04:17 PM
Think about this
Electric angle grinder small motor.
Air angle grinder require a pretty big electric motor on the compressor to provide enough air to run it continuously.
russbost - 10/1/12 at 06:13 PM
quote:
Originally posted by britishtrident
Think about this
Electric angle grinder small motor.
Air angle grinder require a pretty big electric motor on the compressor to provide enough air to run it continuously.
That's basically what I thought when I first heard of this, but it's not an entirely fair analogy as this technology first compresses air in
the engine at aroiund 20:1 compression then injects the super compressed air into this hot air causing it to expand, hence you are releasing energy
from the air a little like a heat pump, but as no one has come up with anything going on with it at present one has to assume it has died a death -
not exactly a surprise!
Re the hybrid/combustion engine argument, we all know a decent diesel is way better than a hybrid, but it won't get the same congestion charge
& tax breaks - please don't try & apply logic to anything that's politically driven!
(No pun intended!)
MikeRJ - 10/1/12 at 07:01 PM
quote:
Originally posted by russbost
That's basically what I thought when I first heard of this, but it's not an entirely fair analogy as this technology first compresses air in
the engine at aroiund 20:1 compression then injects the super compressed air into this hot air causing it to expand, hence you are releasing
energy from the air a little like a heat pump,
Surely having the engine compress a cylinder full of air uses quite a bit of energy? Presumably you get even more back when the compressed air is
injected, but I'm struggling to understand how.
There is a fairly recent update (Nov 2011) on MDIs webiste, the company that invented the engine.
The "AirPod" looks like a bad joke though.
russbost - 10/1/12 at 07:40 PM
The Air Pod is certainly exceptional!!!
At 7kW & 45Nm torque the performance must be eeeeerrrrrrrrrrrrr, stunning!!!
Re the business of using energy to compress the air in the engine first, yes, this must obviously use some power, but presumably gives a bigger
payback in terms of power, I guess you could say the same thing about an ICE whether petrol or diesel as again you use power to compress the air fuel
mix b4 igniting - I haven't tried to examine the intricacies of the energy produded/transmitted in each case (what I actually mean is that I
wouldn't know how to calculate the difference between the 2 systems!!!
)
The more I look at this, the more I fail to see waht advantage it offers over electric, other than, possibly, cost???
hughpinder - 11/1/12 at 09:24 AM
Differences air car compared to an electric car:
1. use your source of power (say a windmill, nuclear when its producing too much, coal and gas stations to stop them having to cycle so much to deal
with renewables...) ) to compress the air directly into 'storage'. Cylinders for pressure storage considerably cheaper than batteries at the
moment.
2. possible to fill one high pressure cylinder from another at higher pressure much quicker than current battery recharge technology.
3. No emissions, except noise,if your initail power generation is 'clean'.
4. No mining of rare metals etc for the batteries - are there enough of these materials worldwide if everyone went to this technology? No batteries to
degrade.
5. Very large volume for energy storage - 30Kwh (about what a diesel engine gets from a gallon) ~ 1.5m3 at 300 bar! - I haven't worked out how
much that would weigh - Also if everyone did it, would there be enough air to compress, or would be all be asphixiated??
Hugh
russbost - 11/1/12 at 01:31 PM
quote:
Originally posted by hughpinder
Differences air car compared to an electric car:
1. use your source of power (say a windmill, nuclear when its producing too much, coal and gas stations to stop them having to cycle so much to deal
with renewables...) ) to compress the air directly into 'storage'. Cylinders for pressure storage considerably cheaper than batteries at the
moment.
2. possible to fill one high pressure cylinder from another at higher pressure much quicker than current battery recharge technology.
3. No emissions, except noise,if your initail power generation is 'clean'.
4. No mining of rare metals etc for the batteries - are there enough of these materials worldwide if everyone went to this technology? No batteries to
degrade.
5. Very large volume for energy storage - 30Kwh (about what a diesel engine gets from a gallon) ~ 1.5m3 at 300 bar! - I haven't worked out how
much that would weigh - Also if everyone did it, would there be enough air to compress, or would be all be asphixiated??
Hugh
Surely 1 & 3 are the same for air or battery?
2 is very relevant, being able to "refuel" in minutes rather than hours is very significant
4 is also very relevant, I have been told, tho' not sure about the veracity or accuracy that there is only enough Lithium on the planet to make
sufficient batteries for about 1/3 of current cars, so that ones a non-starter for me!
5 Not convinced on this one, from calcs other people have done it seems to be suggested that the amount of storage vs efficiency would mean that
something the size of a oxygen welding bottle would get you around 30 -40Km
If it can be made to work, I'm surprised we've not heard more about trialling prototypes by now - maybe they just have a cr*p PR
department!
jossey - 11/1/12 at 02:20 PM
by what ive heard in the Oil industry BP and companies like are buying up companies like this for SILLY money for 2 reasons .....
1 so they can slow production and in some cases stop the new inventions which will endanger the money they earn...
2 so when the oil does run out etc they have ownership of the majority of alternative energy companies. im unsure how real this is but i heard it
while working in an alternative energy company from the PR department.
Last year a USA company who sells AC solar cells (normal are DC so need an inverter) was bought by a ***UNKNOWN*** company for multi millions and then
pretty much dissapearded off the marketing map..
Whats stopping us getting those 100 MPG cars and the 0 FUEL bills with alternative energy... is the answer ENERGY COMPANIES????