Gamma Type Troubleshooting

Discussion on Stirling or "hot air" engines (all types)
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Osama
Posts: 14
Joined: Wed Sep 04, 2013 12:36 am

Gamma Type Troubleshooting

Post by Osama » Fri Nov 22, 2013 7:24 am

I have made a gamma type Stirling engine with the following specs:

Power cylinder volume = 70 cc
Displacer cylinder volume = 100 cc
Compression ratio of displacer = 2
Crank angle = 90 degrees
Cylinder pressure = 101 kPa
Displacer piston stroke = 41.4 mm
Displacer piston length = 47 mm

The power piston and cylinder I used was of Honda 70cc motorbike.

The engine did not run when tested under a bunsen burner's flame. I have ruled out the following tweaks to the engine: Increasing the initial cylinder pressure and reducing frictional effects from the power piston. I am attaching the image of my design.

My piston seals the power cylinder with a teflon piston ring but it creates a lot of frictional effects. Can you suggest a better option? And any other suggestions as to why the engine did not run will be greatly appreciated.
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Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Gamma Type Troubleshooting

Post by Ian S C » Sat Nov 23, 2013 1:11 am

Have another look at pressurised Stirling Engines, both sides of the power piston are pressurised, thus the need for seals at the crankshaft bearings. Your motor should work at atmospheric pressure, but by the photo, I'm not sure of the size of your displacer, it should be about three timed longer than the diameter, the ratio of swept volume is about 1.5 (disp):1 (pwr piston), not sure where you get the compression ratio of two for the displacer. In a GAMA motor the displacer is not in the true sense, a piston, if it were the motor would be an ALPHA type.
Don't pressurise your motor at the hot end of the displacer, but at the crank case end of the motor.
Ian S C

faizan2410
Posts: 4
Joined: Thu Mar 07, 2013 1:08 pm

Re: Gamma Type Troubleshooting

Post by faizan2410 » Sun Nov 24, 2013 10:48 am

In my opinion, the following changes might help in running this engine.
1. Make a new power piston and cylinder of smaller size.
OR
2. Reducing the length of pipe between both cylinders.
OR
3. Using a piston rod and connecting rod mechanism similar to the Displacer Cylinder for the Power Piston Cylinder and then pressurize the engine.
More experienced members are welcome to give their opinions.

Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Gamma Type Troubleshooting

Post by Ian S C » Mon Nov 25, 2013 3:42 am

Osama, where is the fly wheel? Is it the V pulley? In my opinion, you should start again with a basic atmospheric motor of a known design, and get that working, even that can sometimes take a bit of work getting it right. Then read up about pressurised motors, understand how they work, and, using good engineering, you might get a working engine. It's frustrating I know, but you have to start at the bottom and work up. Ian S C

dongita
Posts: 2
Joined: Thu Feb 04, 2016 12:53 am

Re: Gamma Type Troubleshooting

Post by dongita » Sat Feb 06, 2016 10:09 am

hello

dongita
Posts: 2
Joined: Thu Feb 04, 2016 12:53 am

Re: Gamma Type Troubleshooting

Post by dongita » Sat Feb 06, 2016 10:12 am

hello am simon from Nigeria,I built a gamma engine bt its not starting can anyone help me please,tanks.

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