Whats the best way to make an air powered go kart?

I have an old go kart I'm fixing up and decided I want to make it run on compressed air. My question is whats the best way to achieve this? I've been debating between having an air motor drive the wheels directly, or having the air motor turn an alternator/generator to power an electric motor. I figured having the compressed air doing the work would require more torque, and therefor more air, whereas if the air motor just had to turn an alternator/generator it would need less torque and more speed. Any help would be greatly appreciated!

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rickharris6 years ago
Mmm there is an air powered car that uses a conventional engine set up (more or less) It sucks in outside air, compresses it and then squirts in a blast of compressed stored air - this expands rapidly as it is heated by the already compressed normal air and provided drive power. Apparently it works quite well.

Invented by a French man.
thealeks (author)  rickharris6 years ago
i've read about engines like that(mdi air car, gas to air conversions) but i was hoping to skip all that and just go with a pneumatic motor and air tank, maybe make it air-electric hybrid
Issue is storing enough air to get any range AND how to store as it is a potential BOMB.

The links above as for a commercial effort that uses carbon fiber tanks as they tend to split rather than explode (I personally don't like the word "tendency") BUT then again petrol explodes as well.

I am only guessing here but to extract the energy from the air a piston system would be more effective than a turbine.

thealeks (author)  rickharris6 years ago
i was figuring i'd use a scuba tank or fireman's tank(if i could get a hold of one) seeing as theyre built for extreme conditions. and i dont need a huge range or anything, its just a go kart for driving up and down my street, maybe racing against my electric go kart. if i could get a few miles out of a tank of air i'd be just dandy! i do have the original motor(in working condition minus a tranny) that i could convert if need be. it'd probably save me some money too seeing as i wouldnt need to buy anything but an air tank. would it be hard to work out timing for air injection? its just a little 2 stroke single cylinder 32cc engine. thanks for your help by the way!
The timing for the Co2 type engine is injection just slightly before TDC - The pip is slightly linger then the piston so opens the valve just before TDC.

I guess that or TDC would work. The difficult bit might be getting a suitable valve - IF I were doing it and modifying an existing engine I would look for a 4 stroke so I didn't have to worry about lubrication and do the timing electronically from the crank shaft with an electrically operate valve.

The advantage of building from scratch is you don't have to use metal as there is little heat involved. There are may plastics that would be self lubricating and easier to work.
thealeks (author)  rickharris6 years ago
the Co2 type engine does seem to work out the timing on its own, no microcontrollers to control the timing of bursts of air, or anything like that. what kinds of plastics would work? pvc?
Have a look ar AIRHOG engines then - they are a compressed air drive engine for models but I guess it would scale up - They are of a type of engine called a popit valve engine.

The piston has a pip on the top that at TDC pushes open a ball valve in the cylinder head to allow a blast of compressed air through to send the piston back down again.

Link to an animation

http://www.animatedengines.com/co2.html

https://www.instructables.com/answers/Compressed-air-engine-help/

Lots of You tube air engine stuff

http://www.youtube.com/watch?v=G7sfo6drPvs
thealeks (author)  rickharris6 years ago
i was hopin not to have to fabricate an engine, as i would have absolutely no idea where to even begin. i did get some good info from the youtube link though so thanks for your help!
That explanation doesn't sound right. If the thing runs on compressed-air, that's it. "expands rapidly as it is heated by the already compressed normal air" is nonsense really.

Have you got a link to this machine?

L
here

http://gas2.org/2008/07/15/an-air-car-you-could-see-in-2009-zpms-106-mpg-compressed-air-hybrid/

And here

http://www.mechanicalengineeringblog.com/tag/how-compressed-air-car-works/http://www.mechanicalengineeringblog.com/tag/how-compressed-air-car-works/

and the original site

http://www.mdi.lu/english/

I am sure that my explanation was as on the original site a couple of years ago. However - Memory!!

Sorry for the links rich ed is playing up.

Thanks, http://www.mdi.lu refers to an external combustion chamber for heat, that makes sense.

L
thealeks (author)  rickharris6 years ago
also, any idea what word might have made the filters stop my question from posting?
A mystery to us all!
rickharris6 years ago
HDPE or Nylon are the traditional materials - Teflon for the cylinder and piston is self lubricating - needs care when working though.

Aluminium body and plastic piston - Graphite can be used for a piston if not too big.

thealeks (author)  rickharris6 years ago
great thanks ill look into it!
lemonie6 years ago
You'll not store enough air for it to be worthwhile. Liquid petroleum contains much more energy, and doesn't require heavy-steel pressurised tanks.

L
thealeks (author)  lemonie6 years ago
i'd only want to get a few miles out of a tank. its just for driving up and down my street, maybe racing against my electric go kart. i was hoping to shy away from fossil fuels and the like. but thanks for the idea!