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The initial startup delay...???

Discussion in 'Gen 2 Prius Technical Discussion' started by DeadPhish, Jul 27, 2008.

  1. DeadPhish

    DeadPhish Senior Member

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    A brief search here and on Google failed to turn up any definitive data so I thought I'd pose the question to the accumulated knowledge base herein.

    At startup, a cold startup, there is an initial delay of about 10 sec where 'nothing apparently happens'. The vehicle is READY thus is can be driven away or if it just sits the AC will begin to blow cold. After this initial delay the ICE will turn on and begin charging the traction battery, then it too will turn off after about 30 sec.

    My question: What's happening during this first minute or so?

    My own hypothesis is that MG1 draws some juice from the NiMH battery to get the ICE up and spinning in order to get the fluids pumping and to prepare the ICE for operation. During this time the ICE is spinning but not firing. After the 10 sec prep period the ICE begins to fire and if the vehicle is not moving it 'repays' the juice drawn from the traction battery. After repaying its debt it shuts down until needed.

    If the vehicle is moving the ICE both drives the wheels and repays the initial juice boost.

    How close is this viewpoint?
     
    #1 DeadPhish, Jul 27, 2008
  2. qbee42

    qbee42 My other car is a boat

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    The initial delay is just in case you move the vehicle a very short distance, and to provide time for boot up and fluid transfers. If you hit the gas it will start the ICE almost right away. After the initial delay, the Prius starts the ICE to warm it up and warm the emissions control system. How long this takes depends on the initial conditions and outside temperature. After the ICE and emissions system are warmed and all of the early stages are satisfied, the ICE can turn off when not needed.

    Any time the ICE is running it can supply power to MG2 to drive the wheels, power to charge the battery, or both. MG1 is used to spin the ICE and to generate electricity for the electrical portion of the drive train.

    Tom
     
    #2 qbee42, Jul 27, 2008
  3. Neicy

    Neicy Member

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    This should answer your questions:
     

    Attached Files:

    #3 Neicy, Jul 27, 2008
  4. DeadPhish

    DeadPhish Senior Member

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    Yep it's stage 0 to which I'm referring. My interest is...what's actually occurring during stage 0?
     
    #4 DeadPhish, Jul 27, 2008
  5. KMO

    KMO Senior Member

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    Nothing, really.

    It's just a delay giving you time to press the EV button (if you have it), or to select Reverse - which appears to inhibit the engine start-up for a while longer - it's not particularly efficient to reverse with the engine running, as the engine is pushing the car forward.

    I guess it also gives you a chance to change your mind and turn the car off again - I've done that, inadvertently selecting Ready mode when I only wanted to go into Acc mode.
     
    #5 KMO, Jul 28, 2008
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