Philip Duglos Oddball Hit &Miss six Stroke Engine

[Bruno Mueller]

I took the drawings for this engine from Philip Duclos' book “The Shop Wisdom”.
I converted the dimensions to the metric scale and changed them slightly.
I have already finished the first parts.

[crueby]

Looks like a great start!




But, six stroke? How does that work?   

[Sanjay F]

I just wondered that - I found this video, but doesn't explain the 6 strokes?

<a href="https://www.youtube.com/watch?v=81wEKaSo6wM" target="_blank">http://www.youtube.com/watch?v=81wEKaSo6wM</a>

[crueby]

Did a bit of searching on 6 cycle engines - what I found was that they take an extra revolution and fire a second time to more completely burn some un-burnt gasses left in the cylinder from the main firing. So, it does intake/compress/fire/exhaust on the first two revolutions, then compress/fire again on the third revolution, then starts over again. An old concept that does work, more efficient, but with a little less overall power. Interesting!

[Sanjay F]

I have enough trouble with 2 strokes, let alone 6! I have the similar problems with 7 string guitars!

I like the engine though, a wonderful chugging noise, I'm intent on building a hit 'n' miss in future just for that 

[Roger B]

Looks to be a fun project, I will be following along     

I guess that this design allows for extra expansion of the fuel mixture, which gives a similar effect to the Atkinson cycle 

[wbernhard]

Regarding the answer from "crueby"
"Did a bit of searching on 6 cycle engines - what I found was that they take an extra revolution and fire a second time to more completely burn some un-burnt gasses left in the cylinder from the main firing. So, it does intake/compress/fire/exhaust on the first two revolutions, then compress/fire again on the third revolution, then starts over again."

After looking at Phillip Duclos's drawings, my conclusions are as follows:
Based on the shape of the exhaust valve cam and the crankshaft-to-camshaft ratio of 3:1, I conclude the following:
The engine simply makes an additional third revolution with the exhaust valve open. With the exhaust valve open, it can neither draw in nor generate compression. It won't fire a second time either! Why should it?

Best regards, Charly

[rdean33422]

This is my 6 cycle double acting engine I completed a while back.
<a href="https://www.youtube.com/watch?v=jmu07b3MqHA" target="_blank">http://www.youtube.com/watch?v=jmu07b3MqHA</a>

It does operate like Charly said but it does suck in air and blow it out during the 5 and 6 cycles..

Ray

[Bruno Mueller]

I made the next parts.
The bronze bushings are due to arrive next week.
I still have to make the crank bolt.  The crankshaft axles made of 1.7225 (42CrMo4) were pressed in with Loctite 638.
I plan to start the engine with a round pulley and starter cord. That's why there are no claws on the flywheel axle.

After the two flywheels were finished, I had to clean the lathe and the surrounding area from the gray cast iron dust.