Reversed-domed Piston and Bypass Valves for Alpha-type

[pete4513454]

I was wondering if it was fundamentally sound to consider constructing a stirling engine using components similar to regular car engines, such as aluminum cylinders, blocks and heads.

Where instead of heating the hot side by heating the cylinder walls, and or cylinder top, or by heating outside of the cylinder space you could have the heat exchanger protruding from the cylinder head straight down into the block. Where at top dead center a piston with a deep depression in its face that would fit the heating exchanger like a hand and glove (for minimal dead space). Inside the protrusion would be piping for the working gas to go from the regenerator to the middle of the protruding heat exchanger (which is hermatically sealed from the source heat) and then out into the cylinder space. I'm thinking that could allow for the hot side to use components similar to standard car engines. The edges or the top of the piston act as a "shield" to protect the working gas from the cold cylinder walls, and a tapered, protruding heat exchanger would allow the distance between protrusion to the piston to always be less than that of the actual stroke length of the piston and this can allow for a more efficient transfer of heat to the working gas as there would be less of an area of the gas to 'find somewhere to cool down' as the power stroke nears the bottom.

I was thinking that similar protruding heat exchanger can be used for the cold piston.

Also, on the compression stroke of the hot piston why pipe the working gas through the heater? why not have camshafts like on a 4 cycle engine that would divert the gas directly into the regenerator? and for the power stroke of the hot piston why not have the hot gas diverted into the heater just before top dead center similar to how car engines have spark advance? I was thinking that cams could be ground to allow heating possible until the cold piston reaches BDC and then a cam can divert working gas through the cooling heat exchanger through roughly the entire compression stroke of the cold side.

Perhaps a smaller diameter cold piston (for increased compressive pressure) and taking advantage of the exposed cold walls of the hot cylinder in it compression stroke could be used to make a more powerful stirling engine.

[Ian S C]

You'll proberbly need to make a new crankshaft for a start, throw away the aluminium pistons, and make new cast iron ones that fit well enough not to need rings. Forget about a camshaft and valves, have you seen an ALPHA motor working? Yes you can use a nest of tubes, could be quite a number per hot cylinder (3 or 4 dozen maybe more or less), all brazed in (no leaks), but you will need an extention on the hot piston (Heylandt Crown). The motor would proberbly work best with a shorter stroke than the IC motor. As it would be an atmospheric, ie., non pressurised motor, its not going to be starteling in power out put. Not really an ideal basis for a hot air motor in my oppinion. There is one interesting one on this forum, using a V two cylinder compressor, not sure how far its got so far, maybe the builder will see this and tell us. Ian S C

[Ferraccio]

Welcome however,
I remember a book of Andy Ross (also in net) "Macking stirling engines" that report the wordt results making use of parts of an internal combustion engine.
Those who claim to work with piston rings, high masses, and even valve, may be do not have well understood how a Stirling engine works.
The Stirling engine gives thrusts enormously lower than an internal combustion engine, and then are necessary very low masses, low frictions, and an high number of revolutions. For this, in parity of power, the engine is a lot larger, and lighter. But overall the Stirling engine works in closed cycle of gas (valves ?? Why?).
As build a car, nobody would start without seeing what has built Ford and Chevrolet, ...before.
Please look the theory of the Stirling engine, look what other people did about, and if you're able, after innovate and invent.
In other way is really difficult for us also understand.
May be that you do Not speak about a Stirling engine.
Ferraccio,

[Ferraccio]

I correct myself; ....that report the worSt results...
Ferraccio

[Ian S C]

Just a note on cylinder sizes; in an ALPHA motor the two cylinders are of equal volume, so if you made the cold piston smaller, you would need to lengthen the stroke. I imagine that if you are thinking of this large project, you have already built a number of reasonably advanced smaller motors so that you understand the workings of the stirling engines. Ian S C