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engines without intake valves?

Discussion in 'Road Side Pub' started by 1QUICK10TH, Apr 26, 2012.

  1. 1QUICK10TH

    1QUICK10TH Just A GT Established Member

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    Just a thought that has crossed my mind so bare with me if its ridiculous. Every one knows we have direct injection, and we all know its proven to be an excellent development. What if they were to develop a way to inject the perfect amount of air directly into the combustion chamber also? I know its a stretch but maybe it would be beneficial?
     
  2. GloomySVT

    GloomySVT LolUMad? Established Member

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    Good idea, but that's already done with boost lol. The perfect amount of air to make traction a rare commodity :lol1:
     
  3. SID297

    SID297 OWNER/ADMIN Staff Member Administrator

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    It's called a 2 stroke diesel engine. The perfect amount of air is always every molecule that can possibly be crammed in.
     
  4. bodge323

    bodge323 New Member Established Member

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    Modern 2 stroke engines use reed valves.
     
  5. thomas91169

    thomas91169 # of bans = 5203 Established Member

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    How would you expel the expended fuel/air mixture?
     
  6. Mr. Mach-ete

    Mr. Mach-ete Liberals Suck Established Member

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    Call me stupid but don't all compression devices need intake and discharge valves? Intake valves allow air in but slam shut during the compression/ignition stroke?
     
  7. Ironhand

    Ironhand Banned

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    Nope. Some diesels use intake ports(without valves) with a blower to cram air in and they have 4 exhaust valves wrapped around an injector.

    IIRC it was a 8V92TA, it powers the Armys HEMTT.

    Compound Boost anyone? :)
    [​IMG]
     
    Last edited: Apr 26, 2012
  8. Silverstrike

    Silverstrike It's to big to move FAST! Established Member

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    Another engine without any intake or exhaust valves is the Wankle Rotary
     
  9. Digital

    Digital New Member Established Member

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    Aww it's my cars daddy.
     
  10. Rubenk

    Rubenk Wasn't me. Premium Member

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    I've made a post about this before too, no idea where.

    My idea was a big "air injector" that would work jsut like a fuel injector, and then have exhaust ports similiar to a 2 stroke engine.

    I think it was determine that the amount of energy required to power those air injectors would be quite detrimental and rediculous to engineer as well.
     
  11. 10splaya22

    10splaya22 Active Member Established Member

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    A blower/turbo is the air injector you are looking for
     
  12. Rubenk

    Rubenk Wasn't me. Premium Member

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    Except they still rely on a valvetrain.

    My idea is a big direct injection of air from the top of the cylinder head, nearly identical to current direct fuel injection.

    Lets assume a typical 2-stroke engine, except the intake ports dont exist, only an exhaust port near the bottom of the chamber. As soon as the piston comes up and seals past that port, the air is "injected" directly into the chamber with the exact amount you wanted, the piston compresses and the fuel is injected, then spark ignites it all, power is made and the piston moves back down allowing the exhaust to go out of the port. To make it work you would also need a blast of air while the exhaust port is exposed to clear the cylinder.

    This would all require pretty crazy engineering and some extreme precision that just makes it all totally unfeasible.

    I base this only referencing how the below 2stroke engine works(RC nitro engines), I assume larger 2 strokes are the same?

    [​IMG]
     
  13. thepizz

    thepizz OP is a faggit Established Member

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    In because i can be.
     
  14. James Snover

    James Snover Hi-Energy Photon Wrangler Premium Member

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    I think the problem you're going to have is volume. You need 12-14 times more air than fuel. An injector made for that kind of volume would probably look something like ... an intake port. Sleeve valve engines, and Wankels, as far as I know, have been the only real competition to traditional poppet valves in a four stroke engine. Both sleeve valves and Wankels have their limitations. Wankels waste a lot of heat, more than 50%; and sleeve valves are very complicated and induce a lot of friction.


     
  15. Rubenk

    Rubenk Wasn't me. Premium Member

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    All good points...Perhaps you use half of an engines cylinders as the air "pumps" for the remaining cylinders?!

    :poke:
     
  16. Ry_Trapp0

    Ry_Trapp0 Condom Model Established Member

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    why don't we go back to square one and ask what we're actually trying to achieve here. because i'm definitely not seeing the benefit to this.
     
  17. slowr w/o blowr

    slowr w/o blowr New Member Established Member

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    If you are looking at an "air injector", and don't want to be reliant on superchargers or turbochargers, you are still limited with atmospheric pressure. In order to inject the air into the cylinder, you have to draw the air into the "air injector" by causing a low air pressure event. So, now instead of the piston drawing the air in, now you are trying to draw it into the injector.

    Same war, different battlefield.
     
  18. Rubenk

    Rubenk Wasn't me. Premium Member

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    My concept when I thought about it before this thread, was to get a perfect A/F ratio everytime by injecting precise amounts of air and fuel, instead of measuring air and injecting the corresponding fuel to make it right.

    We have direct injection down, and pretty precise valvetrain making it happen now, so I was wondering other ways to make it happen.
     
  19. shanezt

    shanezt corn fed Established Member

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  20. James Snover

    James Snover Hi-Energy Photon Wrangler Premium Member

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    You could, but traditional turbos and centrifugal blowers are more efficient at moving air than reciprocating air pumps.

     

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