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Insignificant EV button "discovery"

Discussion in 'Gen 2 Prius Accessories & Modifications' started by efusco, Jan 10, 2006.

  1. efusco

    efusco Moderator Emeritus
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    I've been observing, over the past few weeks, that sometimes when EV mode (initiated with an EV button) disengages when speed exceeds 34mph that the ECU seems to put the car back into whatever condition it was in just prior to initiation of EV mode.

    IOW, if I was in an ICE-off situation coasting toward a stop and hit the EV button to keep the ICE from spinning back up before I was ready, but then I didn't have to stop after all and was able to keep coasting down the hill until I exceeded 34mph then I would get the triple beep of EV disengaging and the MFD would display either green arrows, yellow arrows (battery to wheels), or no arrow glide without ICE start up.

    OTOH, if I was in an ICE-on condition when I hit the EV button (approaching the crest of a hill or coasting and hit EV to force the ICE off) then continued to glide/coast until 34mph was exceeded the EV mode would disengage and I'll immediately see and feel ICE spin up, at least briefly.

    Of course, if EV is forced to disengage because of acceleration or battery SOC dropping too low the ICE will spin up right away too. But I thought this was interesting b/c I'd noticed the ICE spin up up for no apparent reason as I coasted down a hill near my home.

    I don't think this is of any great import, just an interesting observation...I may try to achieve an ICE-off condition before hitting the EV button in places I know I'm going to have the opportunity to coast down hill for a distance just to save those few Wh of power required for spin up.
     
  2. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    Tell ya what, give me a month and I'll be able to say, "hey that's right, Evan." :D
    Installation in T-18 days and counting.

    While I completely understand what you are saying, I can't understand that reasoning. What your saying means that the computer stops working to determine energy needs while the EV is engaged. It's as though it stores the most recent condition and simply reactivates it upon disengagement. Which causes me to wonder what would happen if you disengage the EV manually. The same results?

    But someone here posted about using EV to snail along and then went downhill. I remember the claim that "I was even able to maintain EV above 35 MPH." Your findings would seem to indicate that EV was actaully disengaged but that the ICE was not needed.

    It's all interesting all the same.
     
  3. efusco

    efusco Moderator Emeritus
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    Indeed, you get a triple beep at 34mph and EV mode disengages...that does NOT mean that the ICE will come on b/c we know we can stay in 'stealth' mode up to 41mph.
     
  4. tripp

    tripp Which it's a 'ybrid, ain't it?

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    Tony that was probably me. I mentioned it in my ice fishing blurb.

    For what it's worth I vastly exceeded the 34 mph "limit" the other day coming back down out of the mountains. I put the car in EV mod because we were in stop and go traffic coming down I-70 East. At one point the traffic broke loose and I was able to coast, still in EV mode, to speeds near or just above 50 mph. I never got the tripple beep. It is confusing though, because when the battery is green, it seems like you can accelerate much harder when you're not in EV mode but still only draw power from the battery. Basically, if you're in the green it seems that the car behaves as if you're in EV mode.
     
  5. Microamps

    Microamps New Member

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    So you are saying that if the state of charge is high (green bars) then the EV mode will allow you to go above 34mph?
    Can someone confirm this please?
    This is very interesting and I'd love to know if it is so, I might have to go and find a big hill.
     
  6. efusco

    efusco Moderator Emeritus
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    There is absolutely not a way to stay in EV mode above 34mph. You CAN stay in electric only mode up to 41mph. You can also go into an ICE spinning but zero fuel burn state at much higher speeds (there may be an upper limit, but I don't know what that limit is).
     
  7. Microamps

    Microamps New Member

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    Thats what I thought. I tried it today, when the battery bars turned green I went into EV mode and attempted to go higher and definitely no go, the ICE started every time. I have noticed that the car will 'coast' (with very light throttle push) showing only battery power to the wheels, I have seen this at up to 66mph, but I assume the ICE is still spinning in a 'no burn' scenario.
    Something else I noticed, our speedos here (Australia) are in km/h so the upper limit for EV use should be 54.71km/h (34mph * 1.609344 = 54.71kph) but in EV mode the ICE starts at 45kmh every time.
    This is a bit dissapointing. Does anyone have any ideas why this might be so? Is this adjustable at all given that the car has the ability to go faster than 45kph in EV mode?
     
  8. tripp

    tripp Which it's a 'ybrid, ain't it?

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    What I noticed is that I did not get the tripple beep when I was coasting down I-70 announcing that I was getting kicked out of EV mode. The SOC was really high and I've noticed that even when not in EV mode you can accelerate much harder if you're in the green than under more typical SOC levels.

    In fact, now that I think about it, the Coastal EV mod doesn't give you a notifying beep unless 1.) your request is denied or 2.) you're on the consumption (maybe we should call it the TB) screen. So what probably happened to me was that since my battery was in the green the car exhibited all the attributes of being in EV mode even though it had automatically switched out as I exceeded 34 mph.

    My only complaint about the mode is that there aren't audible signals that the car's state has changed unless you toggle the MTD. It'd be nice if you always got an audible confirmation when switching between modes.
     
  9. Microamps

    Microamps New Member

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    Even though the US cars are not equipped with the EV button originaly, do you still have the EV light on the dash to confirm that you are in EV mode?
    On an EV button equipped car, as far as I can remember if you have the MFD on the Energy Monitor screen and you press EV there is no audible beep, but if you are on another screen (eg on Consumption) and you press EV you do get an audible beep and the MFD returns to Energy Monitor screen.
    The three beeps when exiting EV mode are the same.
     
  10. efusco

    efusco Moderator Emeritus
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    Tripp,
    Something isn't right. NO matter what means you use to access the EV function the beeps are something programmed into your car, it has nothing to do with how you ground pin 27...once it's grounde d operation, beeps, everything are exactly the same. I suspect you just haven't been hearing/noticing the beeps. Try your experiment with the radio completely off.
     
  11. politically corrupt

    politically corrupt New Member

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    huh? I've run in electric mode upwards of 47 mph...of course the drain on the battery means I can only do it for about 2 miles or so
     
  12. KMO

    KMO Senior Member

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    You can run on electric only at all sorts of speeds, if going downhill - I've done so at over 60mph.

    The only difference is that above 42mph the engine will be spinning to prevent MG1 being over-revved. But it's not consuming fuel. I'd call that electric-only operation (and it appears as such on the MFD), but it appears Evan doesn't; he calls it "zero fuel burn". :rolleyes:

    The extra effort involved in turning the engine electrically normally rules out electric-only/zero-fuel-burn running on the level above 42mph. But this isn't absolute - a good tailwind might get you above 42.