new design, would benefit from advice

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danskor
Posts: 2
Joined: Sun Jan 21, 2007 8:33 am
First Name: Daniel
Last Name: Skorupka

new design, would benefit from advice

Post by danskor »

I’m contemplating a semi-new configuration of Stirling engine. It is
a beta engine, with the power piston connected to a conventional
crank. However the displacer is free, as in a ringbom engine.
Unlike previous ringboms, at least those I have heard of, it has the
displacer sprung directly to the power piston, instead of the air
outside or an enclosed volume outside the displacer cylinder. I
intend to achieve this by attaching a rod to the top of the center
of the piston and boring a small cylinder with the same compression
ratio as the engine into the base of the displacer. Differences in
pressure inside the working space will cause the displacer to move
in an attempt to compress or expand the air inside the displacer’s
internal cylinder, it will also act as a bounce space.
The engine in its current design state is very simple. it
will have only 4 moving parts:the crank, connecting rod, power
piston and displacer The heater is a simple direct heated hot cap.
Instead of using steel wool for a regenerator, the outer surface of
the displacer will be placed close enough to the internal cylinder
wall that they will absorb a significant amount of heat. Most of the
cylinder wall will be made very thin to reduce parasitic short
circuiting of heat, as the base of the displacer cylinder will serve
as the cold end heat exchanger. The engine is intended to be
unpressurised, and small, at 41 cubic centimeters power piston
displacement. But it will hopefully be unusually powerful for its
size, as it will; in its current form have an IC like compression
ratio
I see a variety of uses for such an engine, such as
lawnmowers, or large leaf blowers. My purpose in designing it is to
put on a small boat. Does anyone have any advice or ideas on how to
improve it, and are there any dangers I should watch out for when
building/testing it, as I don’t have a lot of experience as a
machinist or financial room for error.

ps Should I post a sketch in images?
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