Using two gas lawnmower engines to make a Stirling

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aeiou_11375
Posts: 2
Joined: Sun Dec 23, 2007 8:30 pm
First Name: Walter
Last Name: Will

Using two gas lawnmower engines to make a Stirling

Post by aeiou_11375 »

I want to construct a two-cylinder or alpha configured Stirling
engine. See http://www.keveney.com/Vstirling.html

The plan is to connect the shafts of two conventional 3 hp gas
engines 90 degrees out of phase, removing the camshaft so that the
intake and exhaust valves will stay closed as the engines rotate.

I will use the spark plug orifice from each engine to connect the
two cylinders with a tube to allow the fluid to move between the hot
and cold cylinders. I may use a regenerator in that tube to get
better efficiency.

The hot cylinder will be heated with a propane torch and the cold
cylinder will be ice water cooled.

Will this work? Will there be too much friction of the piston rings
to keep the engine from spinning? I read somewhere that the engine
oil will clog the regenerator. Is that an issue?

Thanks,

Walter
bptdude___2569
Posts: 177
Joined: Sat Jan 13, 2007 3:31 am
First Name: Joe
Last Name: McLean

Response to Using two gas lawnmower engines to make a Stirling

Post by bptdude___2569 »

Good luck, I would be interested if you get this thing working.

From what I have been told with a similar attempt was that "normal" engines are just not designed to turn with such little effort to enable the Stirling cycle to function. The lawnmower engines would have to spin like a bicycle wheel, in that you could start it by hand, and have it go for a bit by itself to pass the friction test. The power of the Stirling would then be able to keep it going, once the engine was completed, with not enough left over to do real work.

Hopefully I am wrong, and I'm listening for the next response.
bwebb
Posts: 3
Joined: Fri Mar 21, 2008 1:29 pm
First Name: Bill
Last Name: Webb

Response to Using two gas lawnmower engines to make a Stirling

Post by bwebb »

Walter I am very interested in your idea. what if u use just the compression ring? Maybe try running the oil level a little lower
then normal since the rpm's will be lower and the heat build up
will not be as much as the original design.
drop me an e-mail with what u have so far.
very interested
Bill
bwebb
Posts: 3
Joined: Fri Mar 21, 2008 1:29 pm
First Name: Bill
Last Name: Webb

Response to Using two gas lawnmower engines to make a Stirling

Post by bwebb »

After thinking about your idea it came to me a couple weed eater engines
might work even better as they have roller bearings and use much less oil for lubrication. just block off the transfer ports in the cylinders.
Great now I got another project added to my list.
Thanks Walter I love it.
Bill
gandsnut
Posts: 1
Joined: Sun Sep 07, 2008 9:00 pm
First Name: Robert
Last Name: Magnuson

Response to Using two gas lawnmower engines to make a Stirling

Post by gandsnut »

(Just signed up...) This idea came into my head as well, but the more I cogitate on it, the more I figure it is, IMO, little more than a beefed-up model. If it's power you're after, I don't think the piston size of LM engines is sufficient, but what do I know, I've just started learning about Stirlings. But I have looked at hundreds of pics, articles and animations, and the Stirlings that _do_ some work are the big ones from the 1900's, and it's a fair bet the pistons in those are far larger than LM engine pistons. I'm very interested in projects and results, though, with particular interest in a Stirling that can produce, say, 15Kw for heat and electric generation, running on charcoal.
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