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Thread: the clean two-stroke thread

  1. #151
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    Quote Originally Posted by lohring View Post
    Does this mean I need to get my dog a 3D printer. LOL I love mine for prototyping off the wall ideas. With the current (at least here) opposed piston two stroke fever, I'm inspired to join two of our RC engines into an opposed piston twin. The compact design will make a great speed record engine. I doubt that I'll worry about emissions, though.

    Lohring Miller
    Yes Lohring - get one for your dog as well, why not? at least it won't complain if it doesn't work perfectly!

    When there's OP two stroke fever, then there's still life in the old dog (the two stroke) - so it aint dead yet!! ......... otherwise what else is there?
    Strokers Galore!

  2. #152
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    ceci, trouble is electronics are so accurite, both sensors and delivery. A box of infinitely adjustable electronic parts (ECU) are so cheap compared to the manufacture of mechanical injection parts. As well as the ability to pull 'tricks' that nothing mechanical can do.
    Surrender to the dark side, you will. Smile Emoji.

  3. #153
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    Quote Originally Posted by WilDun View Post
    Ken,
    I am interested in seeing how your scheme works and I don't think that the reeds will overheat but could they possibly hit the piston at certain revs?
    Head mounted intake reeds have been used in millions of reciprocating compressors for over a hundred years.
    As they are the major component affecting the units performance, efficiency & reliability, quite a bit of serious scientific study has been done on their dynamics.

    Under normal circumstances the intake reeds must close when the pressure above the (rising) piston exceeds the static & dynamic pressure of the transfer flow.

    If the engine speed was to exceed the design range by Very significant amounts, harmonics could mess up their behavior a bit.

    Click image for larger version. 

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    The above illustration does not include the damping effect of the sealing face or any travel limiter, if used.

    Cheers, Daryl.

  4. #154
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    Quote Originally Posted by ceci View Post
    You refer to this employee a century ago in Goliath CP 700 engine which is from Bosch.
    In exchange I mean this Spanish (I know you understand Spanish, but I don't know if you know how to read it, that's why I will try to translate it "googletraslate" .
    The system is made up of three parts: two pumps, one of membranes (with carbon fiber sheets) and another line, and an injector.
    The first is located behind the rear transfer of the cylinder and through a hole made in it sucks the gasoline from the tank taking advantage of the upward stroke of the piston. When it goes down, it creates a compression in the crankcase, from which a fitting emerges that drives the piston pump, located after the first pump and sends the mixture to the injector. This, coming from a kart carburettor with a carbon fiber guillotine, thus receives an injection of constant fuel, self-regulated by the engine rotation speed.
    The whole secret of the operation of such a simple and ingenious system lies in the adequate calculation of the surfaces and diameters of the two pumps, to take advantage of the internal pressure and depression effects of the two-stroke engine.
    Thanks for the translation Ceci. I understand spoken and written Spanish (and Italian, French, English, German and even some Dutch) but not everyone will, so translations are always welcome. Of course we have Google Translator, but its capacities are limited; it still thinks a stroke is a medical condition.
    The Martin Clerch system of using the crankcase pressure fluctuation reminds me of a Tillotson pumper carb. I cannot see a real difference. Am I missing something?

  5. #155
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    Quote Originally Posted by Niels Abildgaard View Post
    Please enjoy my more than twenty year old proposal for the ultimate ligthweight two stroke genset.

    https://archive.vn/s7gTY/49bac5b7a1b...09943819dd.jpg

    Two wheel drive with an electric motor in front and rearwheel is within reach.
    Neils,
    Glad to see you have been toying with this idea for so long!
    Next we have to convince people that the present two stroke design will not be able to cope with what is expected of it (by the powers that be) as the bar continues to rise!
    But will any manufacturer want to take the risk? (they have more or less given up except in the area of simple scooters or in certain sporting areas such as Snowmobiles or Karting!).
    Will a driven front wheel ever be necessary?
    Strokers Galore!

  6. #156
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    Quote Originally Posted by Frits Overmars View Post
    The Martin Clerch system of using the crankcase pressure fluctuation reminds me of a Tillotson pumper carb. I cannot see a real difference. Am I missing something?
    The three indicated systems (Martin Clerch, Stihl and Bosch) are not valid to be used in TPI ?.

    The fluctuation in crankcase pressure may not be sufficient to pump at the proper pressure for the present-day injection (Spray creation), which implies that a suitable injector must be developed for this system.

    The pumping pressure can also be increased, interacting with effects that occur in other parts of the 2S process.

  7. #157
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    Progress, but slow.
    It will fit but it will be tight.
    Building the top crankcase pattern next.

    ceci, this one could run carburetors, rival DI?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  8. #158
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    Niel, any chance of a simple pencil drawing of the cylinder piston crank set up you have in mind..im thinking of alternatives to bolting to an existing engine with your casting expertise.. and room for the set up....are there pulley wheels and belts involved for the drive off the crank/cranks?

  9. #159
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    Quote Originally Posted by Flettner View Post
    ceci, this one could run carburetors, rival DI?


    If the OP system can be the future of 2S

  10. #160
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    Possibly not directly related to this thread, but something about some more bits for the cause.

    In this case, the next version of the UHV, which will feature an assymetric layout, this needed new head and reeds. So, you can see the unfinished head (no combustion bowl as yet), the reed valve to suit and the "waste" piece which is a leftover from the wire cutting process. The very thin arms are only 0.5 radially wide.

    Click image for larger version. 

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    "Success is the ability to go from one failure to another with no loss of enthusiasm.”

  11. #161
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    Ken, if you ever need a UHV logo:
    Click image for larger version. 

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    (maybe a bit prickly)

  12. #162
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    Quote Originally Posted by breezy View Post
    Niel, any chance of a simple pencil drawing of the cylinder piston crank set up you have in mind..im thinking of alternatives to bolting to an existing engine with your casting expertise.. and room for the set up....are there pulley wheels and belts involved for the drive off the crank/cranks?
    Do you want last weeks layout, or next weeks layout?
    Surprisingly the design is still in a state of revision, even at this late stage. Ill draw up a general layout if you like and post it.

  13. #163
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    Quote Originally Posted by ceci View Post
    If the OP system can be the future of 2S
    Perhaps,
    But Im going to have a go anyway and have a bit of fun trail riding it, if it runs well enough. I am confident I will get some track time.

  14. #164
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    Quote Originally Posted by Frits Overmars View Post
    Ken, if you ever need a UHV logo:

    (maybe a bit prickly)
    Hahaha Frits, you're right. I often think it is a prick of a thing and what am I doing...
    "Success is the ability to go from one failure to another with no loss of enthusiasm.”

  15. #165
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    Quote Originally Posted by ken seeber View Post
    Hahaha Frits, you're right. I often think it is a prick of a thing and what am I doing...
    Just keep plugging on ......... Proof of the pudding is in the eating!
    Strokers Galore!

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