johnsmachines

machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment. I read every comment and respond to most. n.b. There is a list of my first 800 posts in my post of 17 June 2021, titled "800 Posts"

Category: coffee cup engine

July 1, 2017

Koffiekop Modification

I have been considering this modification for some time, and today I located the aluminium heat sink-radiator material which I needed, and which I knew was somewhere in my stuff.

The Koffiekop Sirling engine requires differential temperatures between the top and bottom plates.  I wondered if installing some heat shedding plates on the top plate might increase the running time on a cup of coffee.

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The heat sink material is glued to the top plate with a heat transmitting electronic silicone glue.

Afterwards I ran a test with a cup of hot water.

The engine ran for 26 minutes!  That is an improvement of about 25% on the best previous runs.  Success!

The Horizontal Mill Engine (HME) is assembled and ready for the D valve to be timed.  This is how it looks.  I wont get to it for a couple of weeks now.

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I did squirt some compressed air into the valve chest, but minimal movement.  Not surprising, considering the position of the eccentric was just a guess.  When I get it going there will be a video.  That crankshaft pin is temporary.  It is a 3mm cap screw going through a 4mm cap screw.  go figure.

 

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September 27, 2015

KoffieKop Engine Working!

I assembled the engine today.  The flywheel was required to be balanced, but I decided to give the engine a run in its unbalanced state, and was quite amazed to see it start up, hesitatingly at first, but then got into its stride, and ran for 13 minutes.

Quite excited at this point, I spent some time balancing the system.  That required the base to be removed, then multiple holes, 7 in all, drilled in the flywheel, to balance the mechanical components.

Then another run.   14 minutes.  Then another, 19 minutes.  Then the best run at 21 minutes.  Very exciting.

So I took it home, and showed SWMBO.   Hmmm.   But what does it do???  She asks.

It just goes…..   It is like an architectural folly.   Just interesting in its own right.   OK?

So this is what you have been spending your spare time on for the last 2 weeks?   Yes.

A bit of a credibility gap here.

The engine, sitting on a cup of hot water, running at about 100rpm.

The engine, sitting on a cup of hot water, running at about 100rpm.

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Best run…. 21 minutes.

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