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New Engine technology: no camshafts!

  1. Apr 17, 2013 #1
  2. jcsd
  3. Apr 17, 2013 #2

    berkeman

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    I'm not able to watch YouTube videos from work. How is this done?
     
  4. Apr 17, 2013 #3

    AlephZero

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    Independent actuators on each valve. The actuators are cylinder shaped surrounding the valve stem. Unsurprisingly, they don't say EXACTLY how it works but the actuators appeared to be self contained apart from electrical connections.

    As well as an arbitrary valve timing, they are give close to a a "square wave" opening and closing cycle - about 3ms to move the valve fully, independent of engine RPM.

    They showed a modified cylinder head on a Saab 95, which has run 2 years / 60,000 km endurance testing.

    Since the valve cycle is completely arbitrary, one of their future ideas is to use the engine as an air pump for regenerative braking, and use the stored compressed air instead of a turbo boost.

    The company is a small Swedish sports car manufacturer.

    They claim a conventional 4-cyl engine could be replaced by a 3-cyl because of the increased valve efficiency, and after deleting the cam drive system etc, the engine would only be half the original length - and also shorter without the height of the cams over the valves.
     
  5. Apr 17, 2013 #4

    Danger

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    I didn't bother watching more than 1/3rd of that for one reason—it's nothing new. If you remember, soon after I joined here about 15 or so years ago, I mentioned that I had designed a 2,000hp engine for my Roadrunner back in the late 70's. It was based upon a McGee (Kangaroo) block/head assembly, but the main reason for the outrageous power was a computer-controlled hydraulic valve actuation system that had been designed in Sweden. Overall power is determined by the lift of the valves, but the power band relies upon duration. My modification to the Swedish design was that rather than plugging a programmed chip into the controller, I fed the signals from a tachometer. That way, no matter what rpm the engine was running at, the duration varied to make sure that the engine was always in the middle of its power band and at maximum allowable lift.
    Someone in the US, at the same time, came up with valve actuators called "helinoids" which also allowed for individually variable valve timing, but not lift. They were conical solenoids that, at 12VDC, could pull something like 200 lbs. in about a millisecond over a distance of 1/4" or so. Leverage was employed to get the desired lift.
    This is still an interesting topic, but let's not think that it's ground-breaking technology.
     
  6. Apr 18, 2013 #5
    I had wondered how old the technology was....video published 2/2013 so I hoped it was something new..
     
  7. Apr 18, 2013 #6

    Danger

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    What does seem different about this is that the fellow mentioned pneumatic actuation. To me, that seems a bit odd for such a high-speed operation, but I suppose that it would provide less noise and vibration than hydraulics would.
     
  8. Apr 18, 2013 #7

    AlephZero

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    I agree the basic idea of independent actuators seems a fairly obvious way to fix the limitations of a camshaft.

    But those cylinder actuators look neat compared with the "obvious" design of keeping everything the same, except for poking the end of the valve stem with something that isn't driven by a cam.
     
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