Author Topic: Two-Stroke Engine Basics  (Read 433 times)

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Offline Philbert

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Two-Stroke Engine Basics
« on: March 09, 2016, 04:15:59 pm »
Two-Stroke Basics Visible Training Aid

I had to learn how a two-stoke engine worked when I started working on chainsaws.  Went to the library and spent some time looking at books - took me a while to 'get it'.  More information is available on the web now.  But here is a simple training aid I made, for use in introductory chainsaw classes I sometimes teach, after seeing one posted on another site.

This is the cylinder from a cheap, garage sale, Homelite clamshell saw, cut in half to show the intake and exhaust ports, bearings, counter weight, transfer, etc.  I also have the clutch and flywheel I can add on.  Very easy to do with a hacksaw, vise, and a little patience.  Even easier if you have access to a metal-cutting bandsaw and belt sander.  I flattened the sides with 80 grit, then 120 grit sandpaper, then hit it with a ScotchBrite polishing wheel to smooth the surface, and eliminate sharp edges.

I added a handle to make it move.  Compression is a little low - might have an air leak somewhere?

Philbert

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Offline Cut4fun .

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Re: Two-Stroke Basics
« Reply #1 on: March 09, 2016, 05:31:12 pm »
I like seeing this type of stuff.  8)

Also like those clear saws the makers put out showing this type of stuff in the cut outs on them.
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Offline Philbert

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Two-Stroke Basics Animation
« Reply #2 on: March 09, 2016, 08:16:00 pm »
There are several Two Stroke animation videos on You Tube, that help illustrate how these engines work.
This one is pretty basic, but clear:

https://www.youtube.com/watch?v=xNLE8G3pC0k

Philbert

Offline Philbert

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Re: Two-Stroke Basics
« Reply #3 on: March 09, 2016, 08:22:04 pm »
Stratified Charge Two Stroke Engines

This video is pretty good at illustrating the Husqvarna X-Torq, 'strato' engines, which use a separate inlet of pure air to flush out the exhaust gas, instead of purging it with a fuel/air mixture. This results in less unburnt gas ('hydrocarbons') being released to the atmosphere as a pollutant.

https://www.youtube.com/watch?v=IY7zQKw4qsQ

Philbert

Offline 3000 FPS

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Re: Two-Stroke Engine Basics
« Reply #4 on: March 09, 2016, 09:25:30 pm »
Very Nice.   When I first started learning 2 stroke engines I got most of my information from the net. 
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Offline Philbert

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Re: Two-Stroke Engine Basics
« Reply #5 on: March 10, 2016, 12:02:54 pm »

Offline Chris-PA

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Re: Two-Stroke Engine Basics
« Reply #6 on: March 10, 2016, 06:25:51 pm »
Very nice!  Mine has been a most invaluable tool to understand how 2-strokes work.  For me anyway it is harder to get the same feel from a video or diagram - I can work that way but it's harder. 

Offline Philbert

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Re: Two-Stroke Engine Basics
« Reply #7 on: March 10, 2016, 06:30:18 pm »
Mine has been a most invaluable tool to understand how 2-strokes work.
Yours inspired me.  I showed it to a neighbor who works on OPE, and now he wants to cut a bunch of lawn mowers, snow blowers, etc. in half!

Philbert

 

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