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Car Lunges in Park

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by walroose, Sep 11, 2006.

  1. walroose

    walroose New Member

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    2006 Prius
    Yesterday I was sitting in a parking lot after a football game waiting to be able to leave. No one was moving and I ended up sitting there for an hour. I had the A/C and radio running the whole time, the battery went down to purple and the ICE would kick in every now and then to charge the battery up to three bars or so. As I was sitting there, I decided to put the car in park since I knew I wasn't going anywhere. When the ICE would kick in to charge the battery, the car would lunge forward like it was going to move. Has anyone else had this problem? It was pretty disturbing, but I don't know, maybe it is normal.

    I just bought the vehicle, I am still on my first tank of gas. I bought the vehicle with 2 miles on it, so far (in a week) I have put a little over 300 miles on it. Sitting in the parking lot did kill my mpg, the average went from 48 to 40. The battery was back to 3/4 charged after one or two miles of driving.

    Thanks,
    Matthew

    PS: Magnetic Grey Package #4, only had to wait three weeks for it! I was worried I was going to miss the 9/30 deadline.
     
    #1 walroose, Sep 11, 2006
  2. benighted

    benighted New Member

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    As far as I can tell it is normal. Mine does the same thing and I've seen several posts like this one before.
     
    #2 benighted, Sep 11, 2006
  3. kDB

    kDB New Member

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    Depends on how you define lunging, two or three inches is normal. Unlike an automatic transmission, the CVT in a Prius leaves the ICE connected to the drivetrain while in park. Therefore, if your on a very, very slight upgrade, the car will move a bit between the parking prawl stops when the ICE turns on and off. Think of how in an automatic in park you can roll the car a bit by pushing it.
     
    #3 kDB, Sep 11, 2006
  4. Schmika

    Schmika New Member

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    It is not a problem, it is physics. When the transverse mounted engine spins, physics creates forward motion. No problem.
     
    #4 Schmika, Sep 11, 2006
  5. Godiva

    Godiva AmeriKan Citizen

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    Was the parking brake on?

    If so, you have a problem.

    If not, you don't.
     
    #5 Godiva, Sep 11, 2006
  6. Marlin

    Marlin New Member

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    The Prius's engine is always directly connected to the wheels using a planetary gear system. There is no clutch or "Neutral" gear. In the center of the planetary gear system is a motor/generator (MG1) that serves various purposes, including spining the engine to start it, and compensating for the rotation of the engine when the wheels are stopped (ie. in Park).

    What you are feeling is MG1 spinning up the engine to start it. Since the stopped engine has inertia which resists the sudden change in rotational speed from 0 RPMs to 1000 RPMs, you feel some of MG1's force being transferred to the wheels.

    Look at the following link for a very good explanation of how the Prius transmission works and all will become obvious.

    http://prius.ecrostech.com/original/Unders...gOnAsIDrive.htm
     
    #6 Marlin, Sep 12, 2006
  7. walroose

    walroose New Member

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    Vehicle:
    2006 Prius
    Thank you for all of the responses, I am glad to hear that what I am experiencing is normal. In my pre-Prius days, I have always driven a manual transmission car (and was initially hesitant to buy the Prius because I like using a stick so much). My main concern was that the engine was not completely disengaging when in Park, and it sounds like that is partly true, but that it is normal for this car.

    Thanks again,
    Matthew
     
    #7 walroose, Sep 12, 2006
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