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Infintely Variable Geared Transmission (D-Drive)

Discussion in 'Motors' started by Sin_Chase, 15 May 2010.

  1. Sin_Chase

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    Last edited: 15 May 2010
  2. PardonTheWait

    Capodecina

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    My brain is visibly pulsing and I have no idea how it works! Looks ace though.
     
  3. GravyMonster

    Capodecina

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    Wow! That's awesome, although I think I'd miss having clutch + manual shift.

    The possibilities for that are endless, although they don't mention any figures in terms efficiency savings.

    Also, surely if the drive can be set for maximum efficiency, it can be set for maximum performance... :D
     
    Last edited: 15 May 2010
  4. taximike

    Hitman

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    How did that guy come up with that.... looks very interesting!
     
  5. Tomsk

    Soldato

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    That bottom shaft is going to take some power (or friction component) to lock it stationary when full power is required on the output side.
     
  6. Clarkey

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    Not hugely convinced, seems like it has a max(min?) ratio of 1:1, and the higher the ratio the more power you have to waste in the system. Doesn't sound like an amazing option for a performance motor.
     
  7. *Moangroan*

    Wise Guy

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    Jeez where did I put those headach tablets.
     
  8. PardonTheWait

    Capodecina

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    I got the impression that it wouldn't need much torque to hold that shaft still? From what the presenter said anyway. Bear in mind I am quite thick so it's very possible I've misunderstood.
     
  9. GravyMonster

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    ^ That's what I thought. There was no torque involved, the lower shaft just needs to be spinning at the same rate/faster than the input.

    Although I'm not exactly an expert in anything mechanical.
     
  10. BigglesPiP

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    Nothing new. My grandad's old Punto had a CVT, and there was the old DAF.

    Edit: Just seen the video, it's an interesting diff being used backwards, you need 2 engines, the one controlling it doesn't need to be as powerful, but it wastes most power at low ratios and reverse. A massive planet gear would alleviate this.
     
    Last edited: 15 May 2010
  11. Sin_Chase

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    Geared? Which is where the biggest advantage of this system seems to be.
     
  12. BigglesPiP

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    The Punto used a belt which pushes.

    Granted this system is geared and has a high capacity for torque, but It's nether convenient or efficient in that it needs power input to achieve low ratios and reverse. We won't see this in cars.
     
  13. Sin_Chase

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    He seemed pretty confident the power inputs required for the shafts to modify the ratios would be pretty small and that a fully fledged build would start putting some figures on it.

    At that point they will know whether it's better than a clutch arrangement. :)
     
  14. uv

    Sgarrista

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    I think one of the main benefits over a CVT is the lack of friction. This device has infinitely less wear, and could handle much higher torque than a CVT.
     
  15. matthab

    Mobster

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    id say the concept is there and with abit of work could be a great alternative.
     
  16. Gribs

    Wise Guy

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    From the looks of things it won't be very efficent at anything other than full speed though
     
  17. Jonnycoupe

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    It strikes me as remarkably similar to the Power Split device in the Prius HSD (Hybrid Synergy Drive).
     
  18. Dogbreath

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    The Prius already has a transmission that works in a broadly similar way. IMO the main problem is that you need something to drive the two shafts that control the "gear ratio", and whatever drives those shafts has to be infinitely speed variable itself, so this suits an electric motor. However, in the scale model with no load on the output of the gearbox there is very little torque experienced by these motors. As the load gets larger, the more torque the speed controlling motors would need to apply, so I suspect in a full size gearbox behind an internal combustion engine, these would have to be quite large motors.
     
  19. markweatherill

    Mobster

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    When this is scaled up to a vehicle transmission, how much power will it really absorb to be able to control the gear ratio.

    It's a clever concept but it replaces the engine driven hyraulic pump that drives a conventional automatic, with another type of drive that will have to provide similar amounts of power.
     
  20. Tomsk

    Soldato

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    I'm no expert either, so I could be wrong.

    The way I see it is if the output side is getting all the power, then the ring and planet gear is driving against the sun gear, so the sun gear has to be held still against all that power.