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What happens in Warp Stealth

Discussion in 'Gen 3 Prius Technical Discussion' started by kgall, Jan 15, 2010.

  1. kgall

    kgall Active Member

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    So I'm cruising at 70 or so, and go out of cruise and the instantaneous MPG goes to 100, or if I'm looking at the energy flow diagram, energy flow from the ICE disappears.
    Ken1784 tells me this is the condition folks call "warp stealth" because you are going so fast that the ICE has to turn, but it is not burning gas, and if you are using energy, its coming from the battery. Indeed, if I'm going downhill, I find I'm sometimes charging the battery slightly.

    So, what's going on with the ICE? Is it freewheeling? Is something driving it?
    Just curious . . .
     
  2. bestmapman

    bestmapman 04, 07 ,08, 09, 10, 16, 21 Prime

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    In the Gen III, Warp Stealth is not the same as the Gen II. It is much harder to obtain, and if you do not have a scan guage or something that can determine fuel flow, then you have no indication of when you are burning gas or are not.
     
  3. dogfriend

    dogfriend Human - Animal Hybrid

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    In the Gen 2, MG1 will use battery power to spin the ICE, but no fuel will be used. You can see this with a Scangauge if you use fuel flow (GPH).

    The reason that the ICE is spun is to prevent overspeed of MG1; by spinning the ICE, MG1 can spin slower than it would if the ICE were stopped.
     
  4. lenjack

    lenjack Active Member

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    You, very quietly, end up on the other side of the universe. :)
     
  5. usbseawolf2000

    usbseawolf2000 HSD PhD

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    ICE would be idling around 1,000 RPM on HV battery instead of using gas.
     
  6. dogfriend

    dogfriend Human - Animal Hybrid

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    Yep. It is usually about 960 rpm, but I have seen it climb to 1100 - 1200 rpm at higher road speeds (> 75 mph). There is a long downhill that I have gone down many times - if I crest the top of the hill at 60 - 65 mph, I will end up at about 78 - 82 by the time I hit the bottom.
     
  7. 924danimal

    924danimal New Member

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    And if you reach 88 mph, you can go anywhere in time. :)
     
  8. dogfriend

    dogfriend Human - Animal Hybrid

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    I have made it to 88, but no time transport occurred. I think that the ICE may restart at 92 - 93 mph, but so far I haven't had the opportunity to try it. ;)
     
  9. qbee42

    qbee42 My other car is a boat

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    You probably needed more plutonium.

    Tom
     
  10. dogfriend

    dogfriend Human - Animal Hybrid

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    What if I just collected a couple of hundred smoke detectors and stowed them in the cargo area? Would that be an acceptable substitute? :madgrin:
     
  11. kgall

    kgall Active Member

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    Maybe not. Toyota has announced some new metal purchases, allegedly to power their new batteries.
    But Scottie tells me it's to synthesize di-lithium crystals.
     
  12. RebelScum

    RebelScum New Member

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    And, as we all know, the only place to get that is from Libyan terrorists.
     
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  13. Bob64

    Bob64 Sapphire of the Blue Sky

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    If it doesn't work, then you can always try a lighting bolt.
     
  14. Philosophe

    Philosophe 2010 Prius owner

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    Which you may find here, but they seem to sell only uranium.
     
  15. Flaninacupboard

    Flaninacupboard Senior Member

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    I'm afaird you'll need more than a few hundred, try 1,955.
     
  16. lonestar

    lonestar New Member

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    There is an explanation now for Gen II. So what happens in Gen III and how do you get into Warp Stealth with a ScanGuage?
     
  17. cit1991

    cit1991 New Member

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    Without getting into discussions about used pinball machine parts:

    My understanding of what people call warp stealth is just an overrun fuel cutoff, but with (some) positive electric drive torque. Cars have had fuel cutoff since the early 80's.

    In a regular car: You're at high speed and don't need engine power (for whatever reason). You back off the gas totally, and fuel shuts off, but the engine still turns, being overdriven by the transmission.

    In the Prius, instead of waiting until zero power is called for, they can cut the fuel when the power demand drops below some number of hp that the motors can provide. The engine still has to spin because there's an RPM limit on MG1, but the power to the wheels and power the spin the (fuel-cut) engine comes from the motors. You're on battery power, and the fuel's cutoff, but there's still some power to the wheels, from the motors.

    When the speed drops slow enough that MG1 can keep up with the ring gear, at 0 planetary carrier speed, then it lets the engine stop turning, and you're in regular stealth.
     
  18. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I don't know but you might ask over in the fuel economy forum.

    Bob Wilson