Design Ideas - "Alpha in a stick"

Discussion on Stirling or "hot air" engines (all types)
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rand3289
Posts: 2
Joined: Thu Apr 28, 2011 2:16 pm

Design Ideas - "Alpha in a stick"

Post by rand3289 »

I am new to the Sterling engines and was thinking for a couple of days about them.
I wanted to find out if anyone has build this type of an engine:
my_sterling.png
my_sterling.png (23.48 KiB) Viewed 5320 times
(see file attached or geocities.ws/rand3289/images/my_sterling.png)
Instead of inline alpha, I would call it Alpha in a stick :)

This is a very convenient configuration since one could just throw the hot end into a camp fire and have electric wires from an internal generalter or water hoses from an internal pump be on the other end of the stick.

Another thing I wanted to talk about is replacing a flywheel.
Flywheel operates on a principle: "Things set in motion tend to stay in motion".
There are 2 other mediums other than solid mass that could in theory produce the same effect: water and electricity.
These effects are less efficient since they are based on interrupting the flow.
Water inertia is used in a ram pump. Electricity flow generates back EMF. Has anyone tried to harness these?

Electical effect could be harnesed by moving a permanent magnet stator inside a coil of a solenoid on the same axis as pistons which would generate EMF during a forward (expansion) stroke.
When the flow of electricity is interrupted by a switch, EMF tries to "shrink" back and produces current in the conductor.
Would this current be enough to drive a solenoid back together with the pressure drop during the cooling phase?

Water pump build in the cold end of the stick would increase the efficiency greately. And we already have a piston there!
To get the effect the pump might have to be a bit below the source water level. This would be a high flow low pressure pump to keep the rpm high.
water flow could be interrupted when piston reaches the right-most position during the expansion swing.
At which point the water coming in will drive the piston back. The valve will be opened in the left-most shaft position during the contraction phase.

I envision the valve as a "sliding piston on the same shaft but a separate chamber that moves only during the left most part of a swing and the right most part of the swing.
It stays stationary during the other say 80% of the cycle to block or keep the flow open.

Let me know what you think... I can be reached directly at rand3289 (at) yahoo dot com
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Design Ideas - "Alpha in a stick"

Post by Ian S C »

Andrey, what you are proposing is a free piston engine,I'v got a GAMMA type free piston engine(I started with a BETTA), the piston, and displace are supported on springs, the springs take place of a flywheel. On the power piston is a magnet (from a microwave oven) this passes through a coil, an acts as a linear alternator, it would work better if I could increase the fequency. About your idea for a ALPHA free piston motor, I'll have to think on that, both pistons will need independant springing, either gas or mechanical. Ian S C
Chriske
Posts: 87
Joined: Sat Oct 02, 2010 1:24 am

Re: Design Ideas - "Alpha in a stick"

Post by Chriske »

This is an example, a very small one.
http://gti-duffel.be/4B/gamma.wmv
Just finished making this drawing and animation, planning to build this one in the near futur.
It's actually a project out of 'Onder Stoom' a dutch journal.


Chris
Mijn thuis is waar mijn draaibank staat...
Ian S C
Posts: 2218
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Design Ideas - "Alpha in a stick"

Post by Ian S C »

Thats a nice design for a BETA type motor, it could be made with a bore ranging in size from 5/8" /15 mm to 60 mm / 1 1/4 "you just scale it to suit, I like the bell crank system, it gets rid of the two crank crankshaft. Well proportioned air cooling works well, if you want to get fancy, you can drive a fan from the crankshaft, or like one of my motors the fan is electric (ex computor), powered by the engine powered generator, it also poweres a radio. You could use water cooling by replacing the fins with a water jacket fot even better cooling. Ian S C
rand3289
Posts: 2
Joined: Thu Apr 28, 2011 2:16 pm

Re: Design Ideas - "Alpha in a stick"

Post by rand3289 »

This configuration has both pistons fixed on the same shaft. Right side's inner diameter would be larger than the left, so when the air expands it moves both pistons to the right thus increasing the volume and moving away from the hot source. Does displacement have to be 90 degrees out of phase with expansion? It would probably not work if they were "in phase" as in this design... What if you make the cold side piston spring-loaded on the shaft?
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