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Thread: Radical New Valve Idea

  1. #1
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    Radical New Valve Idea

    I was thinking recently about engines and came up with an idea. I highly doubt this would be possible but tell me if any of you technical geniuss think this could possibly be pulled off. Ok so my idea is that you could have all of the valves within a cylinder concentrating solely on whatever cycle the engine is on. So if it's in the intake cycle then all four valves in that cylinder (let's just say this is a four valve per cylinder engine) are opened up letting in the air/fuel mixture, and then once we get into the exhuast cycle some type of other little valve mechanism located very closely to above the cylinder moves and switches the path of flow and instead of connecting it to the intake manifold it instead is now connected to the exhaust. And all four valves could open up to let the exhaust gasses out. Then once it went back to the intake stage that other valve mechanism could reconnect it to the intake manifold. Since airflow is such an important factor in an engine's performance i figured this idea would be very beneficial. The one drawback i thought of though is that there would be no valve timing overlap. But possibly you could have just one valve opened for the exhaust slightly into the intake cycle and then quickly closed to provide a little bit of valve overlap. Or maybe you wouldn't even need that because the benefits of 4 interchangeable intake and exhaust valves would be such a gain that valve overlap wouldnt be a concern anymore. So what do you guys think? Plausible idea or just not possible?

  2. #2
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    if its possible to be made......wouldn't that add a lot more parts to the allready many parts in the engine?, and then friction and all the other associated things with that?(may or may not be much, but doesn't addin parts mean more troubleshooting incase something fails?, thats 1 thing you'd want to lower).

    not a bad idea though, since its a way of gettin more air in.
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  3. #3
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    Not sure how the cam-shafts would work though, you'd effectively need two seperate cams (for intake and exhaust) actuating the same valves. Seems like that could be an insurmountable problem tbh.

    Also there is the problem of where you'd put the fuel injectors. Normally they sit just above the inlet valves, but if all 4 valves have to do both intake and exhaust surely you'd need 2 injectors for each valve. Also the injectors would end up getting blasted by exhaust gasses unless they were situated WAY up in the intake system, not very efficient methinks.

    Also there is the issue of the complexities of the gas flow through the intake-cylinder-exhaust. Modern engines are optimised so that you get as effective a flow and 'swirl' of the air/fuel mixture into the engine so that you get the most effective combustion possible. These days a lot of this is done with fancy CFD technology and the angle, size and positioning of the valve openings and the manifolds is refined in this mind bogglingly precise way. I'd imagine the transition between the exhaust and intake phases would be a nightmare in terms of efficient gasflow. Plus it's way easier in terms of packaging to just have air going in on one side of the block, and exiting on the opposite side.

    Also there is the issue of size and complexity that TheOne referred to. As well as over-complicating matters it will surely increase the size and therefore weight of the cylinder head with all the fancy camshafts and plumbing it would require. NOT a good thing.

    Plus as you said yourself, timing overlap would be impossible so that would hinder high-revving performance engines in a big way.

    Nice try, but I don't think it's a feasible solution.
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  4. #4
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    All the camshafts could just have two lobes on them, one lobe for intake one for exhaust.

    I suppose you would have to make the engine a direct injection engine.

    You're right about how that would probably mess up all those good gas flow techniques that they've already developed.

    And yes it would be bigger, heavier, raise the Center of gravity (unless it was a boxer)
    but still with all those problems it seems the benefits would outweigh them, at least to me.

    Having four intake valves would certainly help high performance breathing wouldn't it, I know valve overlap helps alot two but completely doubling the area of which air/fuel can be intaked and exhaustedc certainly seems valuable. I've read articles about how the performance of an engine is closely related to how good and how much the air flow is.

    I dunno, maybe your right, maybe it'll never work, but still i'm sure sometime in the future something like this will come along.

  5. #5
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    http://www.pumaracing.co.uk/pp01.htm
    here's one of the articles i was talking about.

  6. #6
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    I know something similar was used before, a long time ago on single cylinder, single valve engines. The name of the car escapes me..........
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  7. #7
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    You'd lose the ability to oeverlap the gas flows IN the cylinder.

    The exhaust and the inlet valves slightly overlap at the end of the exhust, beginning of the intake cycles.

    This becomes more prevalent in high performance engines with high rate gas flows.

    The exhuast gas flow has an inertia which is used to assist in the drawing of gases down the inlet manifold passed an opening inlet valve. This significantly improves the engines intake of fuel/air at high revs.

    Also additiional valves means more weight, more complexity and more RESTRICTIONS to flow. THe extra valve would have to be ultra efficient to be able to not take off MORE energy from the airflow than the extra valve area by opening all in the cylinder valves does.
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  8. #8
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    the camshaft problem could be overcome by electric cams.i think BMW experimented/poduced an engine with that.

    how about the very few parts of the air/fuel mixture that would be left on the valve. if the hot exhaust gasses rach theese there will be a small unwanted combustion !!.

  9. #9
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    its a good idea but i think rotary valves have it beat and they already exist
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