Newbie on Stirling Engines [Need HELP plz...]

Discussion on Stirling or "hot air" engines (all types)
Longboy
Posts: 106
Joined: Thu Oct 29, 2009 11:17 pm
Location: Tucson, AZ

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by Longboy »

Junkie wrote:I think the hog engine is an alpha type engine ? Not clear but it looks like it. Those don't have displacers, they have two pistons that are hot and cold. A displacer type engine won't work if it's not airtight.
.........The HOG Stirling is a Gamma type engine. That is a displacer in the horizontal cylinder. Longboy.
empty
Posts: 14
Joined: Mon Apr 05, 2010 9:18 am

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by empty »

updates2x, i had the cylinders closed, and soon test it out, hoping it will work this time... sigh...

basically my heat source is like a burning charcoal and the cold source are ice and some water, for the materials used on the cylinder and piston are steel tubes, rendered, and shaped perfectly like a piston and fits the cylinders... sigh
empty
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Joined: Mon Apr 05, 2010 9:18 am

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by empty »

sir, i got a question, should i make the tube connecting both cylinders as small as possible?
if its quite big is it a possible problem for the pressure and making the engine not to work?
empty
Posts: 14
Joined: Mon Apr 05, 2010 9:18 am

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by empty »

Please help me, the engine is made already.

The friction is fine, Minimal Leaks. Crankshaft is good, the angle's are good..

But it won't seem to work/run..

My first analysis is that it's the weight of the piston.. Both pistons are made from steel tubing/tube..

Attached is a design with measurements of the piston..Image



and also a design with measurements of the cylinders..
Image




in the second design the crankshaft support should be above the connecting rod of the displacer cylinder..

the lower cylinder is the displacer cylinder.. please help..
empty
Posts: 14
Joined: Mon Apr 05, 2010 9:18 am

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by empty »

here is another drawing with labels..
what do you mean by the boar and stroke should be the same? the power piston and displacer piston's stroke should be the same? sorry im just new to this, really..
the crankshaft support connected to the water box (cool source), so the end with the crankshaft is the cold end..

Some of my Ideas why it wont work:
Weight of Pistons
Heat Source: Burning Charcoal
Cold Source: Ice
Type of Material Used: Steel
Displacer Piston is fit perfectly to the displacer cylinder.

I'll be posting pictures of the engine in a while.. School Stuff, and Lack of Camera..

Image
Soeren
Posts: 11
Joined: Fri May 08, 2009 3:38 pm

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by Soeren »

empty wrote:...
Displacer Piston is fit perfectly to the displacer cylinder.
...
ok, so let's ask, what is the gap between the displacer and the displacer cylinder. If it "fits perfectly" then I guess, that there is no gap at all. And then we have the reason why your machine will not work. Indeed it cannot work in that case.

regards
Soeren
empty
Posts: 14
Joined: Mon Apr 05, 2010 9:18 am

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by empty »

yeah, that was one of my idea why it won't work..

do you think the weight of the piston is one also? it's made out of steel tubes made into piston-like?

what about the cold source, which is ice? do you think it's enough?
empty
Posts: 14
Joined: Mon Apr 05, 2010 9:18 am

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by empty »

Image
Image

Image

Image



pictures galore, here they are... any comments why it might not be working properly?
Junkie
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Location: England
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Re: Newbie on Stirling Engines [Need HELP plz...]

Post by Junkie »

Your crank is wrong, the two arms should be 90* apart, not 180!

Does it turn smoothly ? Those parts look too big to be easily turned by such a small
engine. I suspect your power piston stoke is too long too (but I'm not sure about that part)
http://www.scraptopower.co.uk My web site, Stirling engines and AE stuff.
Junkie
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Re: Newbie on Stirling Engines [Need HELP plz...]

Post by Junkie »

I can't believe I didn't notice the lack of a flywheel, doh!
http://www.scraptopower.co.uk My web site, Stirling engines and AE stuff.
ralph5656
Posts: 1
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Re: Newbie on Stirling Engines [Need HELP plz...]

Post by ralph5656 »

Sounds like somebody needs to study up on how these engines work. The displacer is not your ordinary piston. It fits loose as a goose in its cyl. The purpose is only to transfer air from one end to the other. The cyl needs to be sealed at both ends so when the air heats up it builds up pressure. Much like a gasoline can sitting out in the sun. Un seal it and the pressure is gone. The shaft from the displacer must have a good seal as it comes out the end of the cylinder yet not produce too much friction. The heated air in this sealed cyl. with its built up pressure is what provides power to push the power piston out its cyl. If you don't get any pressure in the displacer cyl its not going to run.
Longboy
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Joined: Thu Oct 29, 2009 11:17 pm
Location: Tucson, AZ

Re: Newbie on Stirling Engines [Need HELP plz...]

Post by Longboy »

ralph5656 wrote:Sounds like somebody needs to study up on how these engines work. The heated air in this sealed cyl. with its built up pressure is what provides power to push the power piston out its cyl. If you don't get any pressure in the displacer cyl its not going to run.
.........not really, not a good explanation. That's not Stirling principle and its not this pressure upon the power piston that makes Stirling run. A pressure differential between internal heated air and external atmospheric pressure moves the power piston. The displacer shuttles hot air within the engine and there is no build up of pressure in that cylinder ( but an increase of pressure within the engine) while the heat source applied to the displacer cyl. expands the internal air. Cooling of this internal air with a increase in internal volume ( by way of the 90 degree phazing) moves the mechanism. :mrgreen:
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