Is a high power unpressurised stirling engine possible

[Tom Booth]

I'm skeptical that arrangement could work as intended.

What is to prevent the air heating up more or less "instantly", as well as the tube being already filled with hot air from previous cycles?

To operate as described, wouldn't the engine have to run at a very slow RPM to give time for such "hanging around" of the air in the tube?

On the other hand, a two cycle engine relies on, what I guess you could call, the momentum of the air to charge and exhaust the cylinder simultaneously.

Are there any working examples of this kind of engine?

[Sockmonkey]

I'm skeptical that arrangement could work as intended.

What is to prevent the air heating up more or less "instantly", as well as the tube being already filled with hot air from previous cycles?

To operate as described, wouldn't the engine have to run at a very slow RPM to give time for such "hanging around" of the air in the tube?

On the other hand, a two cycle engine relies on, what I guess you could call, the momentum of the air to charge and exhaust the cylinder simultaneously.

Are there any working examples of this kind of engine?

Well, if the final exhaust valve C opened up at the bottom of the stroke before valve D closes, the air would exhaust fully from the tube and it's momentum might be enough to lower the pressure in it slightly below atmospheric. That would reduce back pressure a lot.
I don't know about this particular configuration, but I think it uses the Manson cycle.
I think I misspoke when I used the term "hanging around" as it's more a case of giving the air contact with as much hot surface area as possible for as long as possible by giving it a long path.

[Tom Booth]

The Manson engine is interesting.

manson_heat_engine.jpg (88.33 KiB) Viewed 5210 times

[Tom Booth]

this is an interesting thread: Tin Can with Power!!!

Someone says this is a "free piston Mason engine" but I think they mean Manson.

[Sockmonkey]

this is an interesting thread: Tin Can with Power!!!

Someone says this is a "free piston Mason engine" but I think they mean Manson.

Free piston generally means without a crankshaft, so it counts.

[Tom Booth]

I was wondering about the spelling of Mason vs. Manson (with an N), rather than the "free piston" part.

I tried finding information on "Mason" engines, but didn't find much of anything, so I assume it is just a misspelling of Manson (?)

Or is there such a thing as a Mason engine?

There is this:

https://youtu.be/SkpD0rt012U

[Sockmonkey]

I was wondering about the spelling of Mason vs. Manson (with an N), rather than the "free piston" part.

I tried finding information on "Mason" engines, but didn't find much of anything, so I assume it is just a misspelling of Manson (?)

Or is there such a thing as a Mason engine?

There is this:

https://youtu.be/SkpD0rt012U

I'm pretty sure it's Manson, and yeah it's frustrating how hard it is to find information on them.

[Tom Booth]

This is the most impressive "tin can" engine I've ever seen so far.

https://youtu.be/yG0Rv2jNdas

[Jagang]

What is "constant" about the volume in a Stirling engine?
It's constantly schrinking and expanding.
You couldn't operate an engine without it.

[Jagang]

The Manson engine is interesting.

manson_heat_engine.jpg

I wonder how this engine would do with a membrane displacer a-la TK.
And I wonder if that engine could be fired internally as well, since it draws in air with oxygen.
A tea light IN the hot chamber, or something of the likes.

[Tom Booth]

When I think of "overheating" a Stirling, (not necessarily to the point of causing any physical damage), I imagine it to be simply applying excessive heat over and above what the engine is able to effectively convert into work.

Any excess heat ends up at the "sink" or cold side of the engine, cumulatively, until finally the temperature difference is obliterated.

Stirling engines are generally very efficient at utilizing relatively meager quantities of applied heat. Adding more than the engine can use does not necessarily cause the engine to run any better or stronger or faster.

Ideally, heat should go into the engine and mechanical energy or "work" should come out, with no "excess" heat at all reaching the sink.

I'm not so sure that such an ideal balance is impossible as is almost universally supposed.

A "self-driveing" Vuilleumier heat pump, curiously, takes in heat from both the hot and cold end.

In some circumstances. With some Stirling engines, I think, or believe, a Stirling engine can act similarly to a heat pump. If heat is not added in excess, the engine may actually draw some heat from the cold "sink" as well as from the heat source.

The old "drinking bird" is perhaps an example.

Such an engine may end up using the bulk of it's gained heat-energy for self-refrigeration, being of no real practical value, but the point is, a balance is needed, not just an indiscriminate application of heat a drinking bird will not operate if too much heat is applied either.

https://youtu.be/c-0-zH4Ip7w