My alpha stirling engine not working

[shahzad_744]

ive made aplha type stirling engine but its not working can anyone tell me the possible reasons why its not working? ive attached picture of my engine
link: http://imageshack.us/photo/my-images/43/dq7w.jpg/

[derwood]

Bore? Stroke? No leakage?

[Hawke]

What Ive learned so far which I suppose applies to any Striling Engine type:
(besides ratios of cylinders to each other)

1. Keep the dead volume zones as low as possible
2. Maximize the heat source
3. Maximize the cooling system
4. Use a regenerator
5. Reduce friction and air leaks as low as possible

[shahzad_744]

bore is 4.8cm stoke is approx 6cm both cylinders are equal in volume.. should there be any difference in volume of both heat n sink cylinder?
Ive inserted steel wool inside the whole connection pipe between both cylinders to act as a regenerator and to reduce dead space as much possible..
Ive heated the heat cylinder with benson burner and cooled the sink cylinder with ice..
There's not leakage in cylinder or pipe joints but there's a slight leakage in piston cylinder joint during compression stoke if i manually rotate it with my hand slowly... actually ive used piston of petrol engine just with two compression rings(oil rings not inserted as they increase alot of friction.. even leakage still occurs inserting oil rings).. is that a cause of leakage?
and more over leakage and friction are inversely propositional how can reduce them both?
And ive used a small quantity of engine oil(Havoline API SF SAE 20W-40) between cylinders n pistons to reduce friction.. but when i heat one cylinder with benson burner the oil seems to thin and become like a water increasing friction in heat cylinder and theres also smoke comming out of cylinder.. does i even have to change the oil?

[shahzad_744]

bore is 4.8cm stoke is approx 6cm both cylinders are equal in volume.. should there be any difference in volume of both heat n sink cylinder?
Ive inserted steel wool inside the whole connection pipe between both cylinders to act as a regenerator and to reduce dead space as much possible..
Ive heated the heat cylinder with benson burner and cooled the sink cylinder with ice..
There's not leakage in cylinder or pipe joints but there's a slight leakage in piston cylinder joint during compression stoke if i manually rotate it with my hand slowly... actually ive used piston of petrol engine just with two compression rings(oil rings not inserted as they increase alot of friction.. even leakage still occurs inserting oil rings).. is that a cause of leakage?
and more over leakage and friction are inversely propositional how can reduce them both?
And ive used a small quantity of engine oil(Havoline API SF SAE 20W-40) between cylinders n pistons to reduce friction.. but when i heat one cylinder with benson burner the oil seems to thin and become like a water increasing friction in heat cylinder and theres also smoke comming out of cylinder.. does i even have to change the oil?

[Ian S C]

First, get rid of the piston rings, if you must use those pistons, pack the grooves with Teflon tape or similar. You would be better making new pistons from cast iron, and no rings. Have you fitted a Heylandt Crown to the hot piston, and a extended hot cap on the cylinder?
How smooth, and accurately bored are the cylinders?
A motor this size will need quite a bit of heat.
If you need oil, pure synthetic oil as used in gas turbine aero engines, but if things are well designed very little, if any oil should be used.
Try it without the steel wool regenerator, and fit a proper cooling system, either air, or water, preferably water. Ice is a bit silly, it only lasts a few miniutes.
Have you built a working hot air/Stirling Engine? Ian S C

[shahzad_744]

does it matter using piston rings? as i thought they wouldn't leak as they work fine in internal combustion engines. ive not fitted any crown on pistons they are totally the way they are in petrol engine. And cylinders are thick sleeves of same petrol engine for which pistons are designed. see picture of piston link : http://img543.imageshack.us/img543/9229/zfi2.jpg
ive not even used any extended cap on hot cylinder em heating it from the walls. benson burner is placed below the hot cylinder. bores are smooth i can easily move them with my hands and if i place piston at 180 degree angle and move the wheel with hands wheel rotate fine for 1-2 rotations i guess its quite enough.. but when it comes to 90 degree angle in both cylinders its hard to move cylinders to compression stoke and if i put force on them they start leaking little bit(maybe they would not leak at high speed).. maybe i should decrease my connecting rod pivot from the center of the wheel to reduce the length of piston stoke. Ive also tried it without steelwool regenerator but still it didnt worked..
Would a cast iron piston with head do good work then this piston?

[Ian S C]

Automotive piston rings cause too much friction. You need a thin walled hot cap, it looks similar to the hot end of a displacer cylinder, The Heylandt Crown keeps the direct heat away from the piston it's self. When running the hot end will probably get to at least a dull red heat, hotter the better, and you don't want an aluminium piston near the heat. Aluminium on steel(or anything else) = high friction, cast iron on steel, or better still cast iron = low friction, and minimum oil requirements. A IC engine piston is way too heavy, just think of the power of the IC engine compared to the hot air engine. Ian S C

[derwood]

I think your stroke is to long. Too much compression for the way you are heating it. try changing the stroke to half of the bore diameter. That would probably be a good place to start.

[Bumpkin]

Here's a good article that might relate:
http://www.solarheatengines.com/2012/02 ... g-engines/

Bumpkin