How to troubleshoot any Stirling engine

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info74
Posts: 70
Joined: Thu Aug 02, 2001 7:41 pm
First Name: Brent
Last Name: Van Arsdell

How to troubleshoot any Stirling engine

Post by info74 »

There are three common reasons that Stirling engines fail to run. If
you have a design that you know to be good, here are the things that
can keep it from running.

1. Inadequate thermal transfer. You have to keep the hot side hot
enough, and the cold side cold enough for a Stirling engine to run.
The temperature that really matters is the temperature of the metal
where the working fluid (often air) comes in contact with it. In
general, thinner pieces of metal conduct heat faster with smaller
temperature losses.

Sometimes when a Stirling engine does not run, you are simply not
getting the hot side hot enough, or keeping the cold side cold enough.

2. Too much friction. Many new engines suffer from mechanisms that
aretoo stiff. You want to have a very low friction machine.
Engineers need to remember that it is the absolute amount friction
that matters, not the coefficient of friction.

Make sure that your Stirling engine doesn't have any binding spots in
it's mechanism.

3. Air leaks. When the working fluid is allowed to leak into or out
of the engine there are tremendous losses. Finding and fixing leaks
can be a real challenge. It's even possible to have "internal" leaks
where the air leaks into or out of a hollow displacer. Do everything
you can to make sure that your engine has no external or internal leaks.

This is hardly an exhaustive list of the things they can keep a
Stirling engine from running, or running well, but it is a good
summary of the usual suspects. If you have an engine that fails to
run try spinning it in both the "right and the wrong" direction for
rotation. If the engine is partially working it will often turn over
more times in the right direction then in the wrong direction.
stevesat
Posts: 5
Joined: Sun Nov 26, 2006 12:30 am
First Name: Steve
Last Name: Graehl

Response to How to troubleshoot any Stirling engine

Post by stevesat »

Here is one to add. Make sure your crank is properly phased. It's real easy to set connecting rods 90 degrees apart and then not take into account any angles you may have between your displacer and power piston. Ask me how I know this :) Don't just look at the crank connections, watch the action of the piston and displacer to set your timing.
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