First viable compressed air car: get 200-300km per tank of air.
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First viable compressed air car: get 200-300km per tank of air.
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Re: First viable compressed air car: get 200-300km per tank of air.
#2Compressed air has great power density, but awful energy density. I.e., you can unload power very quickly from it but can't store much at all.
Looking at this http://www.popularmechanics.com/automotive/new_cars/4217016.... popular mechanics article, this engine uses 340 Liters of air (under STP) compressed at 4350 PSI.
If my math is right, that only provides a theoretical maximum of about 55 MJ of energy, which is about the same as about 1.5 liters of gasoline.
A combustion engine runs at about 20% efficiency and, if memory serves, compressed air engines at around 30%. But let's give MDI the benefit of the doubt and assume their engines are 50% efficient.
That means this car claims to be able to go 200-300KM (125-185 miles) on the equivalent of about 4 Liters (or 1 gallon) of gasoline.
Now, getting 150 miles/gallon isn't physically impossible, but it seems pretty difficuly and does raise some red flags to me. And that's assuming they have a 50% efficient engine, which is extraordinarily unlikely. Assuming a 30% efficient engine, this car is doing the equivalent of 250 miles/gallon.
Re: First viable compressed air car: get 200-300km per tank of air.
#3Compressed air has great power density, but awful energy density. I.e., you can unload power very quickly from it but can't store much at all. Looking at this http://www.popularmechanics.com/automotive/new_cars/4217016.... popular mechanics article, this engine uses 340 Liters of air (under STP) compressed at 4350 PSI. If my math is right, that only provides a theoretical maximum of about 55 MJ of energy, which is ab…
Maybe part of the explanation is that it's very light-weight - the car in the photo looks tiny, it says it's made of fiberglass, and my guess is that the engine must also weigh much less than a comparable internal combustion engine (you don't need as much metal to contain the combustion...).
Of course, that probably comes with a heavy price to passenger safety. Fiberglass won't give you any protection in a crush. That may be the reason why Tata is involved and not some European manufacturer. The Euro market has some serious safety regulations.
Re: First viable compressed air car: get 200-300km per tank of air.
#4Compressed air has great power density, but awful energy density. I.e., you can unload power very quickly from it but can't store much at all. Looking at this http://www.popularmechanics.com/automotive/new_cars/4217016.... popular mechanics article, this engine uses 340 Liters of air (under STP) compressed at 4350 PSI. If my math is right, that only provides a theoretical maximum of about 55 MJ of energy, which is ab…
The Quasiturbine engine can be run on compressed air, and in transportation applications, it should (http://qtusa.promci.qc.ca/QTEfficaciteComparative.html) have better than 50% efficiency.
But great power density and awful energy density sounds like something an engineer should work with a little before declaring viability: A hybrid design with some other power source having high energy density, even if it can't deliver it very quickly.
Re: First viable compressed air car: get 200-300km per tank of air.
#5Ok, we won't be burning gasoline in a vehicle, we'll be burning it to compress air when refueling.
For similar reasons I don't get the fuss about electric "zero-emission" cars. Zero? Like electricity just magically comes out of nowhere...
Re: First viable compressed air car: get 200-300km per tank of air.
#6Ok, we won't be burning gasoline in a vehicle, we'll be burning it to compress air when refueling. For similar reasons I don't get the fuss about electric "zero-emission" cars. Zero? Like electricity just magically comes out of nowhere...
Most likely we wouldn't be burning gasoline to compress air for these cars: gas is expensive. Instead, we'd probably use electricity derived from coal, natural gas, or nuclear, with the possibility of better sources in the future.
"Zero-emission" is a reasonable description, as the car itself doesn't give off emissions while running. If you're going to include the emissions given off in the process of producing the fuel, a gasoline-based solution is suddenly much worse, as you need to include the emission costs of finding, extracting, refining, and transporting the gas.
Re: First viable compressed air car: get 200-300km per tank of air.
#7Ok, we won't be burning gasoline in a vehicle, we'll be burning it to compress air when refueling. For similar reasons I don't get the fuss about electric "zero-emission" cars. Zero? Like electricity just magically comes out of nowhere...
It's like software. If you cleanly separate the front-end and back-end it's very easy to tune and swap out the back-end without the user noticing.
Re: First viable compressed air car: get 200-300km per tank of air.
#8"tubular chassis that is glued not welded"
Oh yeah I feel safe already. I wonder what its crash rating will be?
Re: First viable compressed air car: get 200-300km per tank of air.
#9Compressed air has great power density, but awful energy density. I.e., you can unload power very quickly from it but can't store much at all. Looking at this http://www.popularmechanics.com/automotive/new_cars/4217016.... popular mechanics article, this engine uses 340 Liters of air (under STP) compressed at 4350 PSI. If my math is right, that only provides a theoretical maximum of about 55 MJ of energy, which is ab…
Maybe part of the explanation is that it's very light-weight - the car in the photo looks tiny, it says it's made of fiberglass, and my guess is that the engine must also weigh much less than a comparable internal combustion engine (you don't need as much metal to contain the combustion...). Of course, that probably comes with a heavy price to passenger safety. Fiberglass won't give you any protection in a crush. Tha…
Fiberglass won't give you any protection in a crush
Damn, just put the tank of air in front. Any wreck will cause a mighty explosion balancing out the various vectors involved. I haven't done (and couldn't do, really) the math, but this seems perfectly reasonable.
Re: First viable compressed air car: get 200-300km per tank of air.
#10That felt like reading a press release.