hydraulic drive bike

Discussion in 'Cycling Equipment' started by Mark Vieselmeye, May 5, 2003.

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  1. Have you folks seen this before:

    http://www.powerengine.com/aitx001hydbiksum.htm

    It looks ungainly, but the claim is it's as efficient as a chain/deraileur setup, and potentially
    lighter. It gives continuously variable shifting by changing the pump volume. It's not clear what
    range of gearing you can get.

    What do you think, does this concept seem like it would work? What kind of drawbacks might there be?

    - mark
     
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  2. Tim Cain

    Tim Cain Guest

    "Mark Vieselmeyer" <[email protected]> wrote in message
    news:[email protected]...
    > Have you folks seen this before:
    >
    > http://www.powerengine.com/aitx001hydbiksum.htm
    >
    > It looks ungainly, but the claim is it's as efficient as a chain/deraileur setup, and potentially
    > lighter. It gives continuously variable shifting
    by
    > changing the pump volume. It's not clear what range of gearing you can
    get.
    >
    > What do you think, does this concept seem like it would work? What kind
    of
    > drawbacks might there be?
    >

    If anybody has devised a hydraulic drive that is 95+% efficient, while still light, rugged and
    maintenance-free, why are they messing around with bikes? Once Caterpillar and all the other earth
    shifting appliance manufacturers have gratefully taken this device on board, surely the inventor can
    relax, while regarding the Bahamas over the top of a large gin sling, while their pondering their
    sole remaining problem which is: Which island should I buy next?

    Tim.
     
  3. Rlbeldon

    Rlbeldon Guest

    Mark Vieselmeyer <[email protected]> wrote in news:[email protected]:
    > Have you folks seen this before:
    >
    > http://www.powerengine.com/aitx001hydbiksum.htm
    >
    > It looks ungainly, but the claim is it's as efficient as a chain/deraileur setup, and potentially
    > lighter. It gives continuously variable shifting by changing the pump volume. It's not clear what
    > range of gearing you can get.

    Low - 0.5:1 Mid - 1.5:1 High - 3.5:1

    >
    > What do you think, does this concept seem like it would work? What kind of drawbacks might
    > there be?
    >
    > - mark
    >
    Another solution in search of a problem. When will the titanium version be available? :) Ron
     
  4. RLBeldon <[email protected]> wrote:
    : Mark Vieselmeyer <[email protected]> wrote in news:[email protected]:
    :> Have you folks seen this before:
    :>
    :> http://www.powerengine.com/aitx001hydbiksum.htm
    :>
    :> It looks ungainly, but the claim is it's as efficient as a chain/deraileur setup, and potentially
    :> lighter. It gives continuously variable shifting by changing the pump volume. It's not clear what
    :> range of gearing you can get.

    : Low - 0.5:1 Mid - 1.5:1 High - 3.5:1

    Ok. I still can't find this on the website, though. Unless it's in one of the video clips, which
    aren't working for me. Do you know if those numbers are for the two-piston or the four piston model?

    :> What do you think, does this concept seem like it would work? What kind of drawbacks might
    :> there be?

    : Another solution in search of a problem.

    Hmm, so I take you don't think it's a worthwhile idea. I don't suppose you could be more specific
    about it? I mean, the bike pictured obviously isn't ready for prime time, but the question is
    whether the concept is sound.

    : When will the titanium version be available? :) Ron

    No, I think this is ideally suited for magnesium.

    - mark
     
  5. Jon Isaacs

    Jon Isaacs Guest

    >What do you think, does this concept seem like it would work? What kind of drawbacks might
    >there be?

    Reality. Chains are as efficient a drive mechanism as one can find.

    Fluid systems are just not that efficient. As someone else said, make a fluid system that is as
    efficient as a chain and you will retire off the boys like CAT and GM.

    jon isaacs
     
  6. Jon Isaacs <[email protected]> wrote:
    :>What do you think, does this concept seem like it would work? What kind of drawbacks might
    :>there be?

    : Reality. Chains are as efficient a drive mechanism as one can find.

    : Fluid systems are just not that efficient. As someone else said, make a fluid system that is as
    : efficient as a chain and you will retire off the boys like CAT and GM.

    I'm not sure I get the reference. Are you saying bulldozers and such use a chain drive? I imagine in
    that application a hydraulic drive would have other issues like higher pressures and greater heat
    build-up. Just speculating -- I have no background in this stuff.

    - mark
     
  7. Doug Huffman

    Doug Huffman Guest

    Obvious to even the casual observer.

    "Mark Vieselmeyer" <[email protected]> wrote in message
    news:[email protected]...
    > Jon Isaacs <[email protected]> wrote:
    > :>What do you think, does this concept seem like it would work? What kind
    of
    > :>drawbacks might there be?
    >
    > : Reality. Chains are as efficient a drive mechanism as one can find.
    >
    > : Fluid systems are just not that efficient. As someone else said, make a
    fluid
    > : system that is as efficient as a chain and you will retire off the boys
    like
    > : CAT and GM.
    >
    > I'm not sure I get the reference. Are you saying bulldozers and such use
    a
    > chain drive? I imagine in that application a hydraulic drive would have other issues like higher
    > pressures and greater heat build-up. Just speculating -- I have no background in this stuff.
    >
    > - mark
     
  8. Jon Isaacs <[email protected]> wrote:
    :>I'm not sure I get the reference. Are you saying bulldozers and such use a chain drive? I imagine
    :>in that application a hydraulic drive would have other issues like higher pressures and greater
    :>heat build-up. Just speculating -- I have no background in this stuff.

    : Bulldozers use hydraulic drives, but they are not as efficient as a chain.

    : That heat build up you are thinking would be part of a hydraulic system, that heat is work which
    : is lost, a measure of inefficiency.

    : One does not worry about a chain heating up so there is a message in there.

    That it's well suited for dissipating heat into the air?

    : Pushing that fluid through a piece of tubing, pumping it, converting it back into mechanical
    : energy, these things are lossy processes.

    But how lossy? Pistons can be quite efficient can't they? Does the diameter and length of the tubing
    affect how much energy is lost?

    : Then think about a chain going over a couple of sprockets, not many losses there, efficiency can
    : be something like 98%.

    The web site claims 96+% efficiency. Still not as good an ideal chain setup, but an acceptable
    compromise for some of us. So I guess the question is, is 96% a reasonable claim?

    : 200 watts = 2 gal/min at 240 psi.

    Hmm, this brings up another question -- is the efficiency constant over different power levels?

    - mark
     
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