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Stop light surging, lurching??

Discussion in 'Gen 3 Prius Technical Discussion' started by Hybrid_Motorsports, Aug 31, 2024 at 8:34 PM.

  1. Hybrid_Motorsports

    Hybrid_Motorsports New Member

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    Other Hybrid
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    I just got my 2014 and still getting used to my first hybrid but today I felt something strange. I was stopped at a red light in EV mode with the engine shut off and while holding the brakes, I could feel just a slight lurching like something behind me trying to push the car while I hold the brakes. It's hard to explain, its like the feeling when you let off the brake and the car moves forward but it was trying to do it when I was holding the brakes. it was very faint and I barely noticed it for a few seconds until the light turned green. I was never able to reproduce it and I'm questioning my sanity if it was just heavy wind pushing on the car..

     
    #1 Hybrid_Motorsports, Aug 31, 2024 at 8:34 PM
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Touring
    What’s the miles on it?
     
    #2 Mendel Leisk, Sep 1, 2024 at 12:45 PM
  3. ChapmanF

    ChapmanF Senior Member

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    IV
    The engine has a good bit of rotating mass, and the torque to start or stop it often comes through the transmission a little and rocks the car a bit.

    The car makes heroic-ish efforts to keep that rocking to a minimum—if you're parked in a gen 3 with your foot off the brake, you can even hear the car apply the brakes for you an instant before it cranks or stops the engine, just to restrain the motion as much as it can. They also can use MG2 to apply a countertorque trying to hold the car still while MG1 cranks or stops the engine, and they try to pass very quickly through the low-RPM range where the engine resonates with the car body.

    Still, despite all the efforts, you notice the lurch sometimes. Maybe we should just smile and remember how hard they worked to make it not worse.
     
    #3 ChapmanF, Sep 1, 2024 at 1:18 PM
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