Author Topic: A new gearless 4 stroke engine model  (Read 3099 times)

Offline Zephyrin

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A new gearless 4 stroke engine model
« on: February 25, 2016, 10:53:00 AM »
Hi,
As I have said in another thread on the Duclos's gearless by "Yogi", i'm in the way of completing the building of a gearless four stroke engine of my own design.

The base of this model is an aluminium casting of a vertical engine of the early pillar type, reminiscent of steam engines, 22 mm bore and 25 mm stroke, i.e. a model of "moderate" size.
I thought that this model was well adapted to the fitting of a gearless mechanism for exhaust valve, and an atmospheric intake valve as expected on an ancient model, so gearless mechanisms there is ; namely an eccentric drives a ratchet wheel in front of an anchor lever to allow the exhaust valve pushrod to be actuated each 2 turns; a mechanism similar to the one found on some early "Olds" farm engines.

The early phase of the build were described in another forum, in French I confess, but I would bet that pictures would help as it is useless to repeat the same in several forums.
http://www.usinages.com/threads/un-moteur-4-temps-sans-arbre-a-cames.82383/

My engine is now running regularly, and I'm pretty happy with that, specially with the gearless mechanism, which up to now works faultless and faithfully, really amazing, I can't believe it.
My engine lacks of power, clearly, impossible for it to drive a small electric generator from a moped.

After a breaking in period at 900-1000 rpm, for about 2 hours in about 15 min sessions, and two changes of flywheel, my engine runs now at about 1600 rpm, and this seems to be the maximum I can get (and the minimum too !) and  running is still not that regular, it occurs by burst of 3-6 explosions, followed by short "silent" periods, as you may hear.
As there is no hit and miss regulation, I'm now looking at the source of these irregularities. The home made contact breaker maybe does not follow the rhythm, the spring being too soft, or more likely, the limits of this exhaust mechanism are reached as speed increases, exhaust valve stays open owing to inertia? This is a difficult point to analyse.

 I will put a water cooling circuit too, for cosmetics, since i do only short running sessions, and this engine never shows overheat. And more difficult, to replace the ugly wooden block, I will try to cast a new stand in alu, a large step to get over for me.

the last video

and the first run


« Last Edit: March 08, 2016, 05:43:03 PM by Zephyrin »

Offline Roger B

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Re: A new gearless 4 stroke engine model
« Reply #1 on: February 25, 2016, 11:00:31 AM »
Very nice  :praise2:  :praise2:

The inlet valve not fully closing/floating could be causing the misfires.
Best regards

Roger

Offline Alyn Foundry

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Re: A new gearless 4 stroke engine model
« Reply #2 on: February 25, 2016, 11:29:41 AM »
Hello Zephyrin.

That's a nice looking engine.

For the record a patent was granted to Horace Robinson for a " Ratchet wheel " in 1890 !! Yes the idea is that old.

They were fitted to AE & H Robinson " Oblique " style gas engines. Or more affectionately " Chippie " engines. The reason was to get around N A Otto's four stroke patent stranglehold.

I liked the idea so much I used it on my second design " Sphinx " engine. The secret to good operation is a highly finished and polished surface for both wheel and pawl.

Kind regards, Graham.

Offline Zephyrin

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Re: A new gearless 4 stroke engine model
« Reply #3 on: February 25, 2016, 05:50:00 PM »
Hi,
Thanks for the input. As regard the inlet valve, the spring is actually really weak, hard to give a figure but nothing to compare with camshaft driven valve ! since during early test, I could hardly see the admission valve to open on the admission stroke, then, on a guesstimate basis I put a light spring...easy to test stiffer ones and see if it improves running.

I will try to get this patent, and read it,  thanks.
I see pictures on the Internet of your Sphinx engine, wow, about 20 kg weight, my bench will not survive...

Offline yogi

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Re: A new gearless 4 stroke engine model
« Reply #4 on: February 25, 2016, 09:35:46 PM »
That's a fantastic engine!  :ThumbsUp:
I really like the proportions. Did you cast the cylinder/base?

Thanks for sharing.  :cheers:

Offline b.lindsey

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Re: A new gearless 4 stroke engine model
« Reply #5 on: February 25, 2016, 11:39:45 PM »
Nice looking and running engine Zephyrin, especially with the final flywheel. Very well proportioned!  Thanks also for the videos.

Bill

Offline Don1966

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Re: A new gearless 4 stroke engine model
« Reply #6 on: February 25, 2016, 11:59:41 PM »
Nice looking engine and a great runner ........... :ThumbsUp:

  8) Don

Offline littlelocos

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Re: A new gearless 4 stroke engine model
« Reply #7 on: February 26, 2016, 01:36:53 AM »
Hello Zephryn,
Nicely done!  I love the non-typical valve gear engines.
Thank you,
Todd.

Offline Zephyrin

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Re: A new gearless 4 stroke engine model
« Reply #8 on: February 26, 2016, 08:49:48 AM »
thanks for all these kind words.

For the answers, the main alloy casting was made by a young buddy here in France, a true buffs of engine, which happily has found a job in a research lab working on engines and get married, therefore sharing his time with its model engines became very difficult...but maybe he have some castings left over.
http://fabrication-moteur.over-blog.com/pages/Kit_moteur_proposes_casting_kits-1726109.html

Thus I started to do homemade aluminum castings, up to now I made the cylinder head only (a somewhat porous casting)...

For the new flywheel, at first I found it oversized, but it is the result of several trials with lumps of metal, I realized that most of these old engines bear two flywheels to cope with the weight, anyway, he will stay like that.

I cant stop watching at this mechanism, even if nothing is visible while running...
Best regards

PS
I added a new album on the build of my engine on Google photos which now replaces Picasa.
https://photos.google.com/share/AF1QipO2LDkmVEPl_Lk9ZjvvmFo7e4d4A7L1TQ-6-6GBqgxiojhas_pSdAH9rlDCiP6plQ?key=UU5TZzlfcEtLUVZkcERNRld4WjEyRmVObmZSOVBR


« Last Edit: March 08, 2016, 05:46:12 PM by Zephyrin »

Offline Zephyrin

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Re: A new gearless 4 stroke engine model
« Reply #9 on: March 20, 2016, 11:16:00 PM »
 To finish this engine, I did the base with a homemade castings, higher to cope with the larger flywheel, but alas, the inside of the base is a trifle too narrow for the coil and the battery, can you believe that !

hence I had to do the little crate you can see to put all the electrical stuff. Anyway, I think it's still in the proper style.

I also added a cooling circuit, mainly for the show, since the engine do not hoverheat after 10 min.

The engine runs around 1400 rpm and does not slow down or speed up; carby settings for air and gasoline (=petrol?) are weakly active, as is the ignition: some speed up with earlier ignition, and more noise upon delayed ignition.
 
The final video



Offline zeeprogrammer

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Re: A new gearless 4 stroke engine model
« Reply #10 on: March 20, 2016, 11:22:21 PM »
Looks pretty cool. Sounds good too.
And I like that crate.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline yogi

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Re: A new gearless 4 stroke engine model
« Reply #11 on: March 20, 2016, 11:33:19 PM »
Very nice setup! That turned out great!  :ThumbsUp:
It's definitely a smooth runner.
Thanks for sharing.  :cheers:

Offline fumopuc

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Re: A new gearless 4 stroke engine model
« Reply #12 on: March 21, 2016, 05:39:28 AM »
A nice and smooth runner and a very good looking set up of the engine.
Kind Regards
Achim

Offline Zephyrin

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Re: A new gearless 4 stroke engine model
« Reply #13 on: March 21, 2016, 09:27:30 AM »
Hi,
Thanks for the kind comments !
I'm very happy that the ratchet wheel works so reliably and faultless, I'm really amazed. I would not believe that at first.

I can't start it by a flip on the flywheel, I guess that I can't turn it fast enough by hand, to much compression. I need external help to start it !
My engine has no power at all; he can't drive neither a pump or an electric generator, nothing.

I like to see it running anyway, endlessly, but I have to think to the next engine too...
all the best