New air powered engine - WIP

[piterx]

hi guys!

im trying to develop a new air powered engine that wastes less air than usual ones and that is way much smaller...

i was looking at the ceilings when it came in my mind that usual lego pistons could work perfectly...the problem was the air that kept wasting through the cylinder...when i noticed that pistons have grooves for straps.... after a few tries i've found the perfect solution: plumber oakum :) (easy to find, removable and easy to apply)

so i came up with a nice diameter that doesnt allow air to get wasted but doesnt give too much friction at the same time.

and here's the final version of the cylinders

...nothing more nothing less than the usual lego V set...i just need to seal better the cylinder heads to avoid air losses...

now i need to invent something better than the air switch...something that makes the air get into the cylinders in that order you see in the pic...

the nice thing is that with this concept the engine is gonna work like the real one, an "explosion" of air will pull down the pistons one by one, and in that order they will make the axis turn...and i think it's not gonna require too much pressure to run fast...

any ideas on how air should go in that way?

[AndyCW]

Interesting idea. Any idea how to also get the air out of the cylinders? The same approach might be usefull on a two stroke design, but you would need to build your own cylinder case. I think the barriers infront of you in this project are quite significant, but no one ever did anything new by sitting around a claiming that it was impossible.

[piterx]

cylnders are not hermetically sealed, but anyway lets say that

when piston 3 is activated the air in the 1 gets pushed again into the tube...

that's why i definetly need an idea on how to direct air flood...

it's quite tricky :P but i tested it by blowing some air in every cylinder and it works great even because you need just a few amount of air and pressure :P

my main idea was to make a vehicle with a pressurized air tank (it could be enough even the gas to reload lighters that's pressurized) and an air engine with low consumes :)

but it's gonna be enough even if it just works blowing in it lol

[T_Tank]

interesting idea though for firing order your gonna possibly need 1 or 2 pneumatic valves that been modified for minimum friction switching back an forth so you can get it running, also to flip the switch will need some sort of cam mechanic.

[piterx]

yeah i knew about those switches but they seem to require a lot of energy to be activated...

i have something in mind but i dont know how to make it with legos...let me draw it maybe someone of you has an idea :)

[piterx]

ok...i need 4 stupid valves moved by the axis of the pistons...any idea on how to make one :P?

something like this...that you can open and close using not too much energy...there has to be a way

i got also another idea...let me build this and ill show you, but it's not good because it loses lot of air

[Tamas Juhasz]

Very interesting idea with that pistons. I also thought about it a time ago, but because of the air loose it seemed to me impossible. What's the exact diameter and thickness of the "plumber oakum(what's that?)" you used? I thought about O-rings, they are just like a strong rubber band.

You need a very simple valve mechanics, should work like in the real engines a camshaft and valves. But I think the motor will be very weak because of the very short stroke. Will be powerful only in high rpm(like the short stroked F1 engines) imho.

[piterx]

something like this but you really need a few wires...then it's useful if you wet them in water so they will be more tidy and remain in position once you've managed to twist them around the piston's groove...another cool thing is that the oakum doesnt have too much friction inside the cylinder

yeah i think it's not gonna give too much power but that also depends on how much air gets lost during the process...the more air we can save the best it's gonna work...but anyway it's gonna be great even if it just works by itself :P

the problem is that powering a lego car with a pneumatic V8 requires a compressor....it's like if to power your real car you need to attach it to a container lol

this model has almost no friction at all...i just need to improve the sealing of the cylinder heads...im using the wrong piece i have another one in mind...a 2by 2 studs with a single hole in the middle would be perfect...

[allanp]

I thought of doing something similar but could not get it to work with 100% lego. For the valves I was going to use pneumatic tubing that is bent almost to the point of kinking. Then it would take very little power to bend the pipe (via cranks and pushrods or whatever) just that bit more to kink the pipe, closing the valve.

Edited August 27, 2012 by allanp

[ciken]

i think i have found the solution for powering it

you need four switches

only use one output to power your engine then if switch it to the other sid een the air will flow out

i c'ant explain it really good srry for my bad english

[Tamas Juhasz]

Last year I made an LPE(isn't publicized yet), and the valves were operated by a 9V PF M motor, and that was also the regulator of the speed. If the M motor powered faster the valves, the LPE worked on higher rpm. In this case the valves don't need power from the LPE or a piston motor, like yours.

[piterx]

ok, here's how i solved the sealing issue... the old 4x2 plate was losing air in the middle of it so i took a normal 2x2 plate and drilled it to fit the blue piece in it...

i know it's not so orthodox but it was the only way :P

Last year I made an LPE(isn't publicized yet), and the valves were operated by a 9V PF M motor, and that was also the regulator of the speed. If the M motor powered faster the valves, the LPE worked on higher rpm. In this case the valves don't need power from the LPE or a piston motor, like yours.

the problem is that a pf motor goes always at the same speed...

what i'm really trying to do is something like a "real car" system... an engine, a fuel tank and a "carburetor" controlled by a PF M motor working in the same way of an autocenter steering, so it releases pressurized air only when you require it

[Tamas Juhasz]

I made it, runs reliable(but requires a compressor). Can be regulated the rpm. If you don't mind, I can upload a video, of course, I will write that the idea is yours.

Edited August 27, 2012 by Mbmc

[piterx]

sure mate :)

dont worry about writin my name :) knowledge is free

[piterx]

here's an idea of a possible valve system...a soft tube gets squeezed so air can't reach the piston...

i definetly need to make a scheme of the tubes to figure out if it works or not...

[pluto7443]

I'd love a video!

[piterx]

here it is :)

mbmc made a test and it's working...but we need to make it work properly

i really hope one day we can substitute the pf engine with an air/gas one :)

video

[Meatman]

That is a really interesting idea and also pretty cool. One thing though is that I really could never figure out what the purpose is of these engines. You are using one motor to created air pressure just to make another engine move. I really like Nicjasno's engines too except for the fact that the car model has to be followed around by a air hose.

[Tamas Juhasz]

One thing though is that I really could never figure out what the purpose is of these engines. You are using one motor to created air pressure just to make another engine move. I really like Nicjasno's engines too except for the fact that the car model has to be followed around by a air hose.

You are absolutely right. These engines aren't useful for example in a drive around the garden, because of the huge air consumption. They are more interesting and realistic than useful. And this piston engine is even more realistic(compared with internal combustion engines) because of one thing: an internal combustion engine doesn't pull the crank shaft(like LPEs), only push it. And that's why we need at least 4 cylinder.

Edited August 27, 2012 by Mbmc

[allanp]

Well there are single cylinder engines. It's not a problem because most engines spin fast and have flywheels. To get this engine working right will also require massive air consumption. But one advantage you will have over LPE engine is its size. However the LPE engines have tons of power, more than enough to power a vehicle that's to scale to the engine and so are very useful, just not for small models.

[piterx]

this one doesnt need so much air...i sealed it enough good and with a really weak blow the piston goes down...my aim was to use something like this lighter's gas bottle to power it...

it has a good pressure because from liquid state it turnes into gas...i think it could be enough to power it...but i absolutely dont know how much torque it's gonna generate :P

[SNIPE]

How is your engine supposed to suck up air rather than just push it out, the air will escape when it gets to where the crankshaft is of the engine.

[piterx]

if i understood what you meant, the air is not gonna escape anywhere because of the oakum around the piston working like the real car piston's straps

[SNIPE]

when the air is sucked into the cylender hole it will just come out of the other side and escape into the atmosphere.

[piterx]

FINALLY! drivin in my car i was thinking about the damn valve...and i came with this :)

the problem now is how the hell can i make it with lego pieces ... :P

help is well accepted !!!