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shift to neutral takes a second - why?

Discussion in 'Gen 2 Prius Technical Discussion' started by zsnark, Jul 22, 2008.

  1. zsnark

    zsnark New Member

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    Why does it take a second for one to shift from drive to neutral? Going from drive to "B" or drive to reverse it instantaneous, but drive to neutral always takes about a second.

    During the first week or so after purchasing my Prius, I was completely embarrassed when I took my car to a drive through car wash. When prompted to shift into neutral, I proudly tapped the shifter from drive to neutral, only to find the car wash person yelling "neutral! neutral!", while I was thinking - "I did! I did!"

    On the rare occasions that I did put it in neutral during the first few months I owned the car, I was always surprised to find that I never quite made it to neutral at all - I was still in drive! It was very frustrating, although of course I'm obviously used to it now.

    Granted, neutral has minimal utility, but there are times when it does have a purpose. Coming from 20+ years of driving only a standard transmission, I still have a habit or at least the desire of putting the car into neutral on rare occasions.

    So why can't I just flick the shifter in to neutral? (Let me guess - safety? They don't want you to accidentally shift the car into neutral? I had done that standard trans. cars several times w/out any ill effects.)
     
  2. PriuStorm

    PriuStorm Senior Member

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    I don't know, but if I had to guess I would say because it's an electronically controlled CVT, and as such, the transmission is engaged whether you are in D, B or R. The only difference is direction or type of travel, but you're traveling nonetheless. With neutral, you actually have to disengage, and that is not as 'easy' as with a traditional transmission, hence the short delay. Am I close?
     
  3. jiepsie

    jiepsie New Member

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    If the delay wasn't there, the car would shift to neutral and then to drive everytime you shift to drive.
     
  4. JimboK

    JimboK One owner, low mileage

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    I can't answer the question definitively, but that was my thought as well.
     
  5. patsparks

    patsparks An Aussie perspective

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    Worse than that, it would always shift back to neutral as the shift lever passed through the neutral position on its way back to the at rest position.

    As you say, you get used to it then it is no big deal.
     
  6. ZA_Andy

    ZA_Andy Member

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    The delay for selecting neutral not only allows the transition between drive, reverse and braking without having to pass through neutral to do so, but I think it is also a deliberate safety feature - the delay ensures that you can't shift into neutral by accident should you move the selector when not intending to.
     
  7. Ichabod

    Ichabod Artist In Residence

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    It saves space too. If there were another position on the selector to choose neutral I'd guess it would have to be something like right-up from the center position (again for safety) but then the space for the selector would have to be bigger... it consolidates the operation of the lever into fewer possible directions as well, actually simplifying operation for the driver.

    D, R and PARK have electronic safeties: If you're traveling forward, it won't let you shift to R or PARK, so I rather like that you have to *want* to shift to neutral to get neutral. As others have stated, once I got used to it, hitting N is second-nature now and I don't have to think about it.

    I do sympathize with your embarrassing car wash moment though; when you get flustered it's even harder to figure out the right way to do something like that!
     
  8. efusco

    efusco Moderator Emeritus
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    Note that when in motion you can shift to R...the car will go into neutral immediately.
     
  9. qbee42

    qbee42 My other car is a boat

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    Not close at all. There is no "disengage" with the HSD.

    Neutral on the Prius is mostly there for legal reasons. I assume there are some old laws which require it. The Prius shifter lever uses a pattern similar to that of a manual transmission. Without the delay it would shift into and out of neutral every time you moved the lever except for B. The delay is a simple and effective way to avoid this.

    Tom
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Well, there is also a practical reason - suppose you need to push the car due to a powertrain failure. Also, this facilitates brake pad cleaning, as you can coast at a relatively high speed in N, then apply the friction brakes.
     
  11. PriuStorm

    PriuStorm Senior Member

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    If there is no disengage, then it isn't a true neutral. One of the complaints with my eCVT maxi scooter (Burgman) is that there is no neutral. Sure, I can push it around the garage but I have to overcome the friction of the drivetrain. But once in motion and with the scooter on, I can not reach 'neutral' because the drivetrain is always engaged. How is this 'neutral' in motion accomplished in the Prius if there is no disengage?
     
  12. hschuck

    hschuck Member

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    Neutral is accomplished by opening the field winding circuit on both motor generaters. This allows the wheels or the engine to turn independently of the other.
     
  13. PriuStorm

    PriuStorm Senior Member

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    OK, thanks.