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Accuracy of Engine display in Energy Monitor Display

Discussion in 'Gen III 2010+ Prius Technical Discussion' started by JoeRaber, Feb 2, 2012.

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  1. JoeRaber

    JoeRaber Not my real name

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    Really silly question, but when there are no arrows going from the engine icon on the display, does that mean the engine is shut off? When I am going down hill at 70 there is too much noise to hear if the engine is running. If yes, how quickly do the arrows go away when it shuts down?
    Thanks.
  2. macman408

    macman408 Devil's Advocate General

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    The engine is always at least spinning when you're at about 46 mph or above, though it may not be injecting fuel. When there are no arrows, it simply means that the engine is not producing any (significant) power that is being sent to either the wheels or the battery. It may still be spinning in fuel cut-off, or it might just be idling. From the stock gauges, there's no way to tell for sure whether the engine is off or not - that's one reason why some of us get a ScanGauge.
  3. Rokeby

    Rokeby Member

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    +1

    This question has come up before with respect to the Gen II.
    I suspect that the answer remains valid for the Gen III.

    The ICE/Motor Generator/HV Battery/Wheel display is a simplification
    of the real power flows. It has been called a "mimic," though I don't
    know if that's a valid term in the formal sense of engineering/information
    display. At any rate, it is not an indication of the ICE on/off status.

    As a starter, the display cannot be wholly accurate as it only shows
    only one MG, and at times one of the MGs can be generating and the
    other motoring.

    Secondly, in a "no arrows glide" there is a small power flow from the
    HV battery to the MG. IIRC it's ~.75 HP which is not shown.
  4. JoeRaber

    JoeRaber Not my real name

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    Thank you both for your answers. The information helps a lot. I guess I will have to live with a bit of uncertainty because I am not interested enough to get a ScanGauge. I work with and on computers all day at work and so I am content being one of the "just drive it" Prius owners.
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