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Hybrid System Prefers Electric to Gas Engine

Discussion in 'Prius c Main Forum' started by Ebs, Jan 14, 2017.

  1. Ebs

    Ebs Junior Member

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    Many times, I have some trip legs where the engine has been warm enough so the Hybrid System wouldn't need to turn on the gas engine.
    In that scenario, if I drive the car such that the car would run in EV mode for the first several hundred meters (i.e. below 45 mph), then once I increase the speed above 45 mph, even though the gas engine would kick in, however, the power would pretty much come from the electric motor. The gas engine would only charge the battery. I can tell since the sound of the gas engine is very muted; it doesn't roar. Also, I can tell that the acceleration would be softer. And as you might already suspect, the battery would eventually be drained until 2 bars left before the gas engine would roar more to take over the drive. This battery-sourced drive would continue even if the speed of the car is 60++mph.
    Has anyone experienced this? Is there anything we can do to make the Hybrid System switch the power to the gas engine? I've tried turning on/off the Eco mode with no avail.
     
  2. bisco

    bisco cookie crumbler

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    how many miles on her?
     
  3. Ebs

    Ebs Junior Member

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    It's 29K++ miles.
     
  4. bisco

    bisco cookie crumbler

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    what happens if you punch it?
     
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  5. Raytheeagle

    Raytheeagle Senior Member

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    A hurt hand;)?
     
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  6. scott9443

    scott9443 Junior Member

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    I have the same issue. I'll drive 15 minutes to the grocery store and the car will be running normally. After 15 or 20 minutes in the store I'll start driving again and the gas motor won't turn on and the battery will drain. I can only get up to about 40mph on the roads near the store. The car has under 10,000 miles.
     
  7. bisco

    bisco cookie crumbler

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    is it affecting your mpg's?
     
  8. Ebs

    Ebs Junior Member

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    If I push hard, most of the time the system will still use the electric motor as the main source.
    Once, today, it happened again. Then I pushed hard for several seconds, longer than I normally did, with the battery had 50%. Then the system would finally transferred the power to the gas engine.
    The gas mileage would be really good while the battery has enough juice. However, it would dwindle really fast once the battery is drained. So overall, as stated in the owner's manual (yes, I read that ;)), the mileage would suffer if the battery is drained.
     
  9. bisco

    bisco cookie crumbler

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    i have found that it likes to use the battery if the engine isn't completely warmed up.
     
  10. Sean Nelson

    Sean Nelson Active Member

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    Yeah, when the engine is stone cold it uses the battery to avoid unnecessary wear. Then when the engine is moderately warm it will actually feed power back into the battery if it can (i.e., when stopped at a light) so that it's doing useful work during the warm-up period. The battery gauge on my Prius C usually tops out at 6/8 bars (unless I'm recapturing energy via regeneration while going downhill), but during the warm-up period it often goes up to 7/8 bars.
     
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  11. Sam Spade

    Sam Spade Senior Member

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    Your complaint is exactly the OPPOSITE of what most C owners report.....including me.
    I find that the battery is used ONLY in very limited circumstances and switches over to all gas engine well below 40 MPH.
     
  12. Sam Spade

    Sam Spade Senior Member

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    I think both you guys need to go in for a dealer diagnostic......ESPECIALLY if your cars are still under warranty.
     
  13. Ebs

    Ebs Junior Member

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    Well, my scenario was different from what scott9443 experience. In my case, both gas and electric engine were working, however, the acceleration primarily came from electric motor. In scott9443's case, only the electric motor powered the car.
    I was thinking of going to dealer, since the powertrain is still under warranty. But it seems to me this is a bug within the software. Noting that there aren't many having this symptoms, I doubt Toyota would do anything. Or maybe I'm wrong ...
     
  14. Sam Spade

    Sam Spade Senior Member

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    And what exactly makes you think that is wrong.......or a bad thing ??

    The electric motor is SUPPOSED to provide power at times when the gas engine is at it's lowest efficiency. One of those times is during moderate to hard acceleration.
     
  15. Ebs

    Ebs Junior Member

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    Your statement is correct: "electric motor is SUPPOSED to provide power at times ... during moderate to hard acceleration". But it normally wouldn't drain the battery to below 50% of the capacity. Instead, it would conserve the battery at around 80% to 90% of capacity. In my case, since the acceleration primarily driven by the electric motor while the gas engine only charges the battery, then the battery will be drained until it goes down to 20%. And this is true whether I make soft, moderate, or hard acceleration; the electric motor practically powers the car.
    Leaving the battery drained until the minimum forces the gas engine to work harder later and hence, overall, will waste gas more than if the battery is not drained. This reality is consistent with the owner's manual that suggests not to use the battery excessively.
     
  16. bisco

    bisco cookie crumbler

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    sounds like an ecu issue. what has the dealer said?
     
  17. Sam Spade

    Sam Spade Senior Member

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    WHAT ? That makes no sense.
    There is a lot of room between 50% and 90%.

    And if you are saying that the car is designed to try and keep the battery charged up to 80% of it's total capacity.........that is just stupid. Why have a battery in that case ??

    And finally, the computers do make some guesses about what is likely to "happen next" but they are pretty broad assumptions.
    The power source choice is ALWAYS slated toward the most efficient choice AT THAT TIME and the future has to take car of itself.
     
  18. Aaron Vitolins

    Aaron Vitolins Senior Member

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    I think that it would be a good idea to a dealership and ask to test drive one or two other Prius C's. New or used! Just my thoughts
     
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  19. Sean Nelson

    Sean Nelson Active Member

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    What he's saying is that the car won't normally drain the battery if the engine is operating in an efficient range, because the losses associated with using the engine to charge the battery and then using that electricity to run the electric motor make that less efficient. If the battery is at 80%, it should stay at 80% under those conditions. And since he's expecting the engine to be operating in that range, he doesn't understand why the car is using electric power and running the battery down.

    I think that what's happening to him is that the engine control unit, for whatever reason, has decided that the engine is in a condition where running off battery power is preferable. Warming up from a cold start is an obvious example of that, although he's claiming that the engine isn't cold.
     
  20. Sam Spade

    Sam Spade Senior Member

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    The problem here IS......he has no good way to know which mode of power usage is the most efficient at any given moment.
    AND based on some things he has said, I think his conception probably is WAY off.

    With my C just puttering around town, the battery continuously goes up and down over every period of .....maybe 15 minutes or so......and stays at a high state of charge ONLY when my speed continuously exceeds about 45 MPH.