HyCam engine runs to make waste heat?

Discussion in 'Toyota Hybrids and EVs' started by CamryDriver, Nov 12, 2018.

  1. CamryDriver

    CamryDriver Active Member

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    So this could be a coincidence but I tested my theory that the engine in the HyCam will run just to make waste heat. At he end of a trip the heated seats were on and the climate control set to 71. The car was running in the driveway even thought the car was stopped. The instant I turned the climate control to off the engine also turned off.
     
  2. sam spade 2

    sam spade 2 Senior Member

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    Un-known to you, the climate control probably was running the A/C a little to keep; the humidity down a bit.

    The engine does NOT run just to waste......anything.

    It does, however, run sometimes to maintain a minimum engine temperature......and to make heat for the occupants.
    That is not exactly "waste heat".
     
  3. wjtracy

    wjtracy Senior Member

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    If the HV batt needs charge the engine will run, also depends on what warm-up stage the car is in...so we cannot tell. Also in winter if the cabin needs heat.

    How do you like the car though?
     
  4. bisco

    bisco cookie crumbler

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    what do you mean by waste heat? if the temp is set above low, you are asking for the engine to run if necessary to make heat
     
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    that's not waste heat, it's demand heat.
     
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  6. CamryDriver

    CamryDriver Active Member

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    Okay, "demand heat" then.

    The question was if perhaps leaving the heat off would impact mileage in the cooler months. Not having posted the question I can understand the confusion.

    Last year at a certain point it seemed as if the engine would rarely enter autostop/EV in the cold. It seems like perhaps dressing warmer and leaving the heat off will give the mileage a boost this Winter. I suspected the reason was to make "demand heat" and we are now half way to proving it.
     
  7. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    That's how it works. Nothing to prove. The only way for the car to make heat to keep the engine warm or to keep the humans warm is to run the engine. If you set the cabin temperature to 71F like you said, that would run all the time in some of the temps we get, the engine would never shut off.

    When driving the Prius in the cold, I generally turn the HVAC off when I am approaching a stop light and turn it on again before I go. Don't have to, it will work without any fancy button movement. But I hate the idling engine. On the highway, just let it do its thing. When you first turn the car on, all the stuff in the car has to absorb heat too. This is where cabin pre-heating is a nice thing.
     
  8. qettyz

    qettyz Active Member

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    Heat has to come from somewhere, its not free.
    I see my mpg drop during the winter, gas is used to make heat as engine is running more to heat itself. If one would turn climate all off and freeze then there is some mpg to gain;)

    Engine wants to be at least 40C and more if there is heat demand.
     
  9. CamryDriver

    CamryDriver Active Member

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    Well let me tell you. I recently saw a YouTube video where a couple car guys (one was Doug Dimero) discussed what car they would buy if cost was no object. It was not well explained what exactly that means but as a primary daily driver I'd pick the HyCam. As a second car maybe a Tesla. The newer Rolls Royce is very nice but it is just too much (waste) for me. Maybe a Rolls with a more efficient drive train but there is no such thing.

    There are a couple reviews around here that outline more details. I'd perhaps have some of the nitpicks fixed by a custom shop but I'd be driving a Camry. I love the car.
     
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  10. CamryDriver

    CamryDriver Active Member

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    Me too.

    The automatic functioning is adequate most of the time but there are times it could use a little predictive help as the car is reactive not predicative.

    I really hate it when the engine cuts on right as you are coming to a stop and then cuts off just as you are about to accelerate from a stop. This happens very rarely and I usually take steps to discourage this but it does still happen at times.

    One of the hybrids I read about evidently has some predictive ability. The GPS tracks your daily commutes and over time plans accordingly. Pretty cool idea! I think it was the Ioniq.
     
  11. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I've really come to think that Toyota's best cars are the stealth hybrids. Hybrid powerplants without all the in-your-face technology-for-the-sake-of-technology.

    You see similar heat behavior even in non-hybrid cars. A few from the newest generation will raise their idle or select lower gears specifically to burn more fuel for heat, if the cabin heat knobs are set high.

    You can use a block heater to bank up heat on grid power and cut fuel use. It's a free thermal battery and the charger is cheap. Might as well use it.
     
  12. sam spade 2

    sam spade 2 Senior Member

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    This is really NOT a good idea.

    The moisture just from your breath can, and often does, frost over the inside of the windshield and suddenly block your vision completely.
    Especially if you are facing into the sun.

    No need to be toasty warm but a little heat for the defroster really is required.
     
  13. Prodigyplace

    Prodigyplace Senior Member

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    We tend to think of Toyota Hybrids as fuel efficient vehicles, but that is really secondary. Foremost, they are low polluting vehicles.

    In order to minimize pollution, when the engine first starts, it runs until it is up to optimal operating temperature to minimize pollution. After that , it will run if climate control takes the temperature below optimal.

    The heat is not wasted but is needed to minimize pollution, given anticipated demands.
     
    #13 Prodigyplace, Nov 13, 2018
    Last edited: Nov 13, 2018
  14. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    [​IMG]

    It is not a bug, it is a feature.
     
    #14 JimboPalmer, Nov 13, 2018
    Last edited: Nov 13, 2018
  15. Prodigyplace

    Prodigyplace Senior Member

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    That's the one with a gasoline heater in the "frunk" to provide cabin heat. I remember those.

    [​IMG]
     
  16. Prodigyplace

    Prodigyplace Senior Member

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    Hey, no waste heat there, just frozen buns.;)
     
  17. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I've owned several aircooled VWs, some with the auxiliary gasoline heaters. Those heaters were amazing! Flick the switch and whoosh! hot air out the vent instantly.

    Yes, it burnt a lot of gasoline, but it was very efficient about safely turning it into heat, and that was the whole point.

    Some of the same manufacturers currently produce similar units that rapidly heat your watercooled engine antifreeze, and the latest models can talk to the cloud and start heating the car by remote command.
     
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  18. Prodigyplace

    Prodigyplace Senior Member

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    Do they use the Gen 2 antifreeze thermos too? ;)
     
  19. bisco

    bisco cookie crumbler

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    my wife's hycam has heated seats, which are nice for at least the backside, and allow lower heat settings resulting in some mpg gains.
    but cold weather still causes the engine to run more to maintain minimum programmed temp
     
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  20. wjtracy

    wjtracy Senior Member

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    ...although we have low MPG in cold weather, the nice thing about winter is how kind and gentle it is on the HV battery. You are always keeping batt charge in the safe range due to extra electrons due to the heater being on. Also the cold weather itself bathes the battery in low temperature which retards long term degradation reactions internally in the battery. At the same time battery power is lower due to low temp and MPG is a greater debit perhaps than regular ICE's.

    In contrast the A/C robs a lot of electrons and you see purple bars (low batt ) more often and hotter areas need replacement HV batteries more often. As a side benefit better MPG as partial compensation for the bad aspects.
     
    #20 wjtracy, Nov 13, 2018
    Last edited: Nov 13, 2018
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