Prius Gen II modes of operation

Discussion in 'Gen 2 Prius Technical Discussion' started by spinkao, Aug 6, 2009.

  1. spinkao

    spinkao New Member

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    Hi everybody,
    I read some Internet articles on Prius modes of operation and also know them well from my own experience, but there is one thing that really puzzles me, and I was unable to find any relevant answer.

    I don’t understand why is it necessary to stop and wait with the ICE running in order to get from mode 3a to 4. I mean, I know it works this way, but I don’t understand why is it designed this way? I am sure there is a good technical reason behind this, but I don’t see it. Why cannot the transition occur immediately after ICE reaches the desired temperature?

    This is very inconvenient; it often happens that I have to drive wastefully in 3a, because I cannot stop to get into 4 for a relatively long time because of traffic conditions. After some time, the car goes to 3b, which is better, but the situation is solved only temporarily, as it gets into 3a again.

    I would be very grateful if somebody could explain me the technical reasons behind this. Also, does gen III Prii behave the same way, or are their operating modes different?


    Thanks for your time :)
     
  2. JimboK

    JimboK One owner, low mileage

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    No one has explained it in the 3+ years I've been hanging around PriusChat and related forums. Toyota engineers certainly could do so, but they haven't publicly. I agree it's a nuisance, but that's life; we have no choice but to live with it.

    I've made it more tolerable with the addition of the EV switch. Then I can shut the ICE down at will in sub-34 MPH conditions, where previously the S3a ICE run-on during deceleration was most frustrating.
     
  3. spinkao

    spinkao New Member

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    Thanks for your answer. I can comfortably live with it, but it arouses my curiosity, you know :). I tried to use the EV button to shut the engine at will, but it kicked in as soon as I disengaged the EV mode :rolleyes:.

    Do you know whether the Gen III Prius behaves in the same manner?
     
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