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regen quits if traction control engages?

Discussion in 'Gen 2 Prius Technical Discussion' started by abq sfr, Aug 12, 2008.

  1. abq sfr

    abq sfr New Member

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    I think that at speed, regen will quit and 100% friction brakes will engage if you hit a pothole or something else that kicks in traction control (or is it abs or stability control?), even if it's only for less than a second. Before a red light, at around 45 mph, I started a long slowdown run with brakes on lightly, hit a pothole and had the "glide effect" decreased braking caused by the trac for a second, and the scangauge indicated no SOC increase where I would have expected at least a couple percent increase as I slowed to a stop. Any opinions?
     
    #1 abq sfr, Aug 12, 2008
  2. firepa63

    firepa63 Former Prius Owner

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    It's the ABS kicking in momentarily when you hit a bump with the brake pedal depressed. It's normal.
     
    #2 firepa63, Aug 12, 2008
  3. rigormortis

    rigormortis Active Member

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    all regeneration can do is slow down (but not to a complete stop) the car by spinning in reverse and sucking power from the front axles. it cannot distinguish which side (left or right) of the car to suck power from, and there is no regenerative braking on the rear axle.
     
    #3 rigormortis, Aug 12, 2008
  4. abq sfr

    abq sfr New Member

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    If you're slowly slowing down at 30-40 mph and the friction brakes are not engaged, why would the friction ABS brakes do anything?? The brakes are not even taking part in the slowing, they don't have anything to do until you're down to 7 mph, unless you really stomp on the brakes. I think its traction control causing a switch from regen to friction, and there being a lag of a second, and you get no further regen as you slow to a stop.
     
    #4 abq sfr, Aug 13, 2008
  5. qbee42

    qbee42 My other car is a boat

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    You are correct. It's the traction control system, not ABS, and it kicks in to protect the HSD from shock. With regenerative braking, as soon as traction is lost, the Prius kicks over to 100% friction braking. There is a very short transition while the friction braking kicks in, and it causes the sensation that the Prius has surged ahead or accelerated. It hasn't, but the reduced g load in the braking direction tells your brain that it's an increased g load in the forward direction. Ours brains are easy to fool in this way. Many new Prius drivers insist that this is a horrible safety issue and Toyota should recall all of the Prius until it is fixed. If you keep your foot on the brake it's not an issue at all, unless you are tail-gating in the first place.

    Tom
     
    #5 qbee42, Aug 13, 2008
  6. FireEngineer

    FireEngineer Active Member

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    When it happens try throwing it in "B" mode. The fact this happens was the primary reason for me to install the BT plate.

    Wayne
     
    #6 FireEngineer, Aug 13, 2008
  7. abq sfr

    abq sfr New Member

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    Thanks for the confirmation Tom. Next time it happens, I'll take my foot off the brake and then reapply, that way it should reset and I'll get at least some regen. FireEngineer... that BT plate is starting to sound like a good idea. Thanks again for the EBH install! Hope all are well....
     
    #7 abq sfr, Aug 13, 2008
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