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Does the ICE always come on after startup?

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Species5618w, Jun 9, 2013.

  1. Species5618w

    Species5618w Member

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    I understand that the ICE comes on to warm up the coolant and recharge the battery if low. However, in the middle of summer and with a full battery, my ICE still comes on even if I have just parked for a short while. Is that normal? I have heard that it doesn't come on for some people if the battery is not lower than 2 bars and the coolant should stay warm for a couple of days.
     
  2. fuzzy1

    fuzzy1 Senior Member

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    Hours, not days. But the exhaust catalyst also cools, and needs to be warmed to function correctly.
     
  3. lachrisb

    lachrisb Junior Member

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    I have been able to get my C to start in EV mode the past few days by holding down the EV button then starting the car. That way if I am pulling the car in or out of the garage to grab something I don't waste fuel.
     
  4. fuzzy1

    fuzzy1 Senior Member

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    Your warm location helps make this possible.

    I don't know if the 'c' is the same, but the U.S. version of the Liftback needs the coolant to be 68F (20C) or warmer to allow this. Otherwise, EV mode is refused. In my climate the garage is too cold about 360 mornings of the year, but it works very well in warmer places. Outside of North American markets, this EV threshold temperature is usually set much lower.

    Can any 'c' owners confirm whether it has the same EV threshold temperature?
     
  5. lachrisb

    lachrisb Junior Member

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    That's interesting, although it makes sense. I wonder if it could damage anything.... That would be a bummer. :-/
     
  6. Fauxknight

    Fauxknight Active Member

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    Minutes not hours even. Depending on the weather of course, if left in the sun on a scorching hot windless day it won't cool down very fast. I do a lot of back to back short trips, and, even in 70-80 degree weather, if I'm not on the road again within 5-10 minutes I usually have another warm up cycle.


    When you force EV mode with the button the car has two different states it can enter, Cold EV or Hot EV. Either way you must have a decent charge on the battery to use the EV mode button. In pure EV mode force by the button you get a lot more power than Stealth EV* mode and can even go well into the ICE's normal range on the Eco meter.

    Cold EV - You pushed the button before the ICE is warmed up, possibly before its even been turned over. Max speed in cold EV is 10 mph.

    Hot EV - You pushed the button after the engine has properly warmed up. Max speed in Hot EV is 25 mph.

    Cold EV is good for preventing the ICE from wasting gas when all you want to do is move the car out of the driveway or change parking spots. Hot EV isn't as usefull, but I've played with it occasionally when the circumstances line up perfectly. I've only used Hot EV in a 25 mph speed limit area where I want to get up to speed fast (cars behind me, or turning off a major road with cross traffic), but I don't want to bother firing the ICE up for just a few seconds.


    *Stealth EV mode is not forced by the EV mode button, it's the state the car enters when it decides it doesn't need the ICE. Power output is much lower, maxxed at half of the Eco bar, but the max speed is much higher than a forced EV mode, somewhere around 43 mph.
     
  7. Species5618w

    Species5618w Member

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    Interesting, no wonder I get another warm up cycle after a coffee stop. So that's normal.


    I can't seem to be able get into EV button mode at all unless I have 6 bars of battery. That also explains why I got kicked out of EV mode (without warmup) this morning almost right away, even though I could usually get out of my neighbourhood on EV (after warm up).

    Thank you all for your replies.
     
  8. Fauxknight

    Fauxknight Active Member

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    Yeah, forcing with the EV mode button requires a decent charge on the battery. Normally I find forcing EV with a warmed up engine worthless, because once the engine is warmed up you might as well coax the car into Stealth EV mode and not be restricted by the silly 25 mph speed maximum. Only real downside to Stealth EV is the power output restriction.
     
  9. Fauxknight

    Fauxknight Active Member

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    Also remember that depleting the battery means it isn't available to assist the ICE, forcing more gas usage when the ICE is running, and, of course, draining the battery too low forces the ICE on to recharge it. Because of these things, running in EV mode doesn't save you much gas in the long term, except in the case of Cold EV to move the car out of the driveway or change parking spots, where a warm up cycle would be a complete waste.
     
  10. It works for me at 4 or more (out of 8) bars of battery... I've never seen the battery lower than 2 or higher than 6.
     
  11. fuzzy1

    fuzzy1 Senior Member

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    My ScanGauge shows that the engine coolant temperature doesn't cool enough in 5-10 minutes to force another warmup cycle. Something else is forcing it.
    Make that three different states, not two:
    No EV: engine coolant 67F or colder;
    Cold EV: engine coolant 69F to something warmer (132F ???), max speed 9 mph;
    Hot EV: engine coolant above 132F (???), max speed 25 mph.

    (I don't know what happens right at 68F. In over a hundred tries, I could never trap my ScanGauge displaying this particular value.)
     
  12. ztanos

    ztanos All-around Geek!

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    The EV only button will only turn on with more than half a charge, but you can run it all the way down to 2 bars as long as you don't turn it off, or press the throttle too hard.
     
  13. Fauxknight

    Fauxknight Active Member

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    Perhaps a little longer than 5-10 minutes, but not too much longer than that, it's certainly not a low battery ICE cycle (I do get those too on occasion). Is it not possible to stop one trip just on the verge of entering a warm up cycle, causing another one no more than a couple of minutes later? I don't have a ScanGauge, but I doubt I'm heating it up much outside of the warm up cycle, we're talking about lots of short trips that are sometimes only 6-9 minutes in length, counting a minute or two to complete the delivery. ICE usage is usually under 50% of the distance traveled (I'm at 50% EV distance travelled for the last 2k miles driven).

    On the other hand, if one was driving on the freeway a lot and making high ICE usage for their trip, then I can see where your coolant temperatures would be on the higher end and take longer to drop back to a required warm up cycle.


    I've always had access to Cold EV when I wanted it, but I didn't own the car over the winter.
     
  14. Fauxknight

    Fauxknight Active Member

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    2 bars is minimum (allowed by the computer at least), before you drop below 2 bars the ICE will kick on and start charging the battery. This is the second type of forced ICE cycle. When you drop this low you the ICE can't get an assist from the battery, so you'll have reduced power output.

    6 bars is the maximum that it will charge off the ICE, the remaining space is left for regenerative braking. I've seen 7 a few times after a normal long stop, but you see it a lot more often when going down a long hill that is steep enough to require at least some regenerative braking.
     
  15. Ah awesome, I had been wondering if it was possible to overcharge the battery since I never saw past 6, even though I've pulled the gear into B off the highway.
     
  16. Rob.au

    Rob.au Active Member

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    With the ScanGauge you can compare the State of Charge against the display - it hits 8/8 in the mid 70s% so you still have a little way to go before the real maximum of 80%, after which the car will start spinning the ICE to get rid of any additional energy.

    In short - don't stress, the car has it under control.
     
  17. Rob.au

    Rob.au Active Member

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    My Australian 'c' never starts the ICE until the HSI is pushed past the half-way line in the ECO area. If I keep it below the mid point I can drive it around using EV only, without needing to press the EV mode button. Once started, it will then warm the coolant up to at least 40°C. I was away for a few weeks and missed our coldest outside temperatures this year and I park in an underground car park that's a relatively stable environment, so I've actually never yet seen the coolant below 20°C on start up, but it's probably coming.
     
  18. minkus

    minkus Active Member

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    My ICE comes on about 10 seconds after starting the car, regardless of what I'm doing.
     
  19. Rob.au

    Rob.au Active Member

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    Okay so an update.

    At home my morning starts now show a coolant temperature of 18°C, with no change in behaviour, just takes a little longer to warm up to 40°C.

    Last night, parked outside in our capital city of Canberra, my poor c was subjected to -4.7°C overnight (23.5°F... yes, yes, all you real winter "I have to drive in snow" people may scoff) and the coolant was showing +1°C on the ScanGaugeII when I got in, by which time the sun had started melting the coating of frost that I never thought it would see.

    As a test, I sat there for a couple of minutes in READY mode with no cabin heating on and confirmed that the ICE did not start by itself. However, the moment I so much as touched the accelerator pedal, it came on and stayed on. Clearly it took far longer than normal to reach 40°C but it didn't stop there... from recollection it went to about 55°C and even then, it would come on much more readily than normal. By the time I stopped, I had a fairly high SoC from all that.

    EDIT: This is without using the EV button, as I've never needed to use it on startup before.
     
  20. Species5618w

    Species5618w Member

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    Interesting, they might have different firmwares for the Aussie version. My comes on regardless. However, in very hot days, short stops would not trigger another warm up cycle.