Possibility of single stroke engine.

Discussion in '2-Stroke Aircaft Engines' started by Ethan Appleton, Jun 17, 2019.

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  1. Jun 17, 2019 #1

    Ethan Appleton

    Ethan Appleton

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    Looking into for the future of building my own plan. I like the common engines but I just want something unique per say. Would a single stroke engine be possible in the case that fuel and air would be pre mixed and injected just before top dead center then ignited and burned for the down stroke/combustion. Before starting what would be the new compression stroke a valve would open pulling a strong enough vacuum to pull the exhaust and close letting the piston rise to another spot before top dead and open a valve with the fuel and air mixture already mixed and under pressure for the combustion to be pushed into the cylinder to be burned next?
     
  2. Jun 17, 2019 #2

    gtae07

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    Where's the pre-compressed air getting compressed?


    The place for brand-new engine concepts is the test bench and the lab, not a flying airplane. You'd be better off using an existing engine, especially on a unique airplane.
     
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  3. Jun 17, 2019 #3

    Jerry Lytle

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    Piston down stroke, piston rises (up stoke) moves up, sounds like a two stroke to me.
    I have true single stroke in my closet, a Springfield model 1903 caliber 30, it has no return stroke what so ever.
     
  4. Jun 17, 2019 #4

    akwrencher

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    The level of complexity to make something like that work would be an order of magnitude more complicated than existing engines. Plus, you really can't fit more than one combustion event per revolution. It's just not practical (possible?). There are plenty of unique engine solutions just in the conversion realm and they are plenty challenging enough of a project for even the "advanced" guys to get right.
     
  5. Jun 17, 2019 #5

    Ethan Appleton

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    I was thinking an electric driven compressor when the engines starting then let it be engine driven or geared up from the engine.
     

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  6. Jun 17, 2019 #6

    Ethan Appleton

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    Well it would be if your piston was at that top level. Fuel and air would be injected under pressure (same as if the piston compressed it) infighter that’s my Down stroke- at the very bottom of the stroke just before it would return up a valve opens and pulls via a vacuum the exhaust then leaves the piston chamber and as the piston rises just before it is at its peak fuel and air is pushed in then infighter and it repeated. One stroke per revolution via one intake and one exhaust.
     
  7. Jun 17, 2019 #7

    akwrencher

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    The thing is, it still has two strokes, an up stroke and a down stroke. It can't have less than that. Perhaps you could explain in more detail the process you are envisioning and the benefits you hope to achieve.
     
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  8. Jun 17, 2019 #8

    Riggerrob

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    The inventor is going to need to devote much time to developing intake compressors and exhaust suction pumps. The external plumbing will probably exceed the weight and complexity of the combustion chamber.

    The only way I can see making this a true 'single-stroke" is installing a floating piston that fires when moving in both directions. Install intake and exhaust valves at opposite ends of the cylinder.
    The next challenge is figuring out how to attach a single floating piston to a crankshaft??????
    The nearest I have seen - so far - is a Scotch Yoke connecting a pair of pistons. ?????????

    An intriguing concept ......
    Wanders off scratching head .........
     
  9. Jun 17, 2019 #9

    akwrencher

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    Perhaps a linear generator used as a hybrid?
     
  10. Jun 17, 2019 #10

    Hephaestus

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    It seems to me you're talking a 2stroke like an old Cox 049...
     
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  11. Jun 17, 2019 #11

    pictsidhe

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    Description sounds like a steam or CO2 engine. Neither of which have found much use in man sized aircraft.
     
  12. Jun 17, 2019 #12

    poormansairforce

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    Sounds to me like your trying to reinvent the wheel except this time its a square one....
     
  13. Jun 17, 2019 #13

    Swampyankee

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    Gee, you could do something like this:

    Compressor -> Combustion chamber -> expander; it's called the Brayton or Joule cycle.

    There would be a shaft connecting the expander to the compressor. Google Brayton (or Joule) cycle. You could make the combustion chamber a wave rotor.

    Wave rotor:
    https://www.egr.msu.edu/mueller/NMR...eviewOfWaveRotorTechnologyAndApplications.pdf
    https://www.grc.nasa.gov/www/cdtb/projects/waverotor/index.html

    Positive-displacement Brayton Cycle

    https://thecornishengineer.files.wordpress.com/2015/06/the-joule-cycle-engine-23102003.pdf



    https://watermark.silverchair.com/v...8iIjKpQJNhH57h3QParuTy4KnSwFx4zHvnoqJFNN1dllQ
     
  14. Jun 17, 2019 #14

    pictsidhe

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    Wave rotors are gas driven compressors. Combustion is not done inside them.
    Are you thinking of pulse jets?
     
  15. Jun 18, 2019 #15

    Swampyankee

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    No, a topping cycle with a wave rotor. I’m not sure anyone actually built a wave rotor topping cycle anywhere except a test cell.
     
  16. Jun 18, 2019 #16

    pictsidhe

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    I think that Brown Boveri built a few. Combustion was not in the rotor.
     
  17. Jun 18, 2019 #17

    bmcj

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    I’m with Jerry and AK, the new design described by the OP is still a 2-stroke engine. Hephaestus hit the nail on the head, this sounds like a reed-valve engine used in model airplanes.

    The only real difference between a 2-stroke and the OP’s idea is the pre-compression of the air and fuel before it is injected into the combustion chamber, which means extra complexity as well as compressing an explosive mixture in part of the engine NOT designed for explosive expansion.
     
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  18. Jun 18, 2019 #18

    Aerowerx

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    (Somehow the quote from pictsidhe didn't get quoted.)

    Ah, shucks!

    You stole my answer!

    As I recall, they were rather finicky little beasties to get working properly. And tended to make a mess with all the unburnt castor oil and alcohol flying everywhere when that port opened. Not very efficient either, I would guess.


    Hmmm. Wonder what a 40 HP one would sound like. Freight train in your living room???
     
  19. Jun 18, 2019 #19

    bmcj

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    Remember, engines like the Rotax 503 are also 2-stroke.
     
  20. Jun 18, 2019 #20

    Turd Ferguson

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    single stroke engine would have to fire at TDC and BDC, no?
     
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