Newsweek: end coming for Toyota's CVT?

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by Jack 06, Nov 16, 2005.

  1. Jonnycat26

    Jonnycat26 New Member

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    I think a lot of it has to do with the lag that Toyota has dialed into the transmission. With a manual, or conventional automatic, if you nail the gas pedal, the transmission kicks down and you get power. With the Prius, you nail the gas pedal, and it thinks about it for a second or two, then starts the rev building.
     
  2. jared2

    jared2 New Member

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    "the Prius to not have much low end torque"

    I have noticed this. The Prius has plenty of power for highway passing, but it has far less power than a Camry when starting from a stop. On the other hand, it is by far the quietest and smoothest ride I have had, except when really pressing the accelerator. You gain in one way and lose in another.
     
  3. Tideland Prius

    Tideland Prius Moderator of the North
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    I've noticed that but I just assumed it wanted to use the electric motors first then get the engine to rev as the accelerator passes a certain angle. However, I've also noticed a lag in our 02 Camry. I'd press the accelerator and nothing would happen. I'd accelerate but not as fast as I want to, so I'd have to press a bit harder, force the downshift, then I'll get the power I want. With the Prius, I get it almost immediately.

    Also, you can attribute this lag to the drive-by-wire throttle system. If you don't want the lag, drive a vehicle without one. It's annoying but I guess they'll improve in the future.
     
  4. hobbit

    hobbit Senior Member

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    One reason you don't get instant vroom from the throttle is that
    opening a throttle more slowly actually saves a lot of gas. If you
    want to snap a throttle open and expect results, you have to enrich
    the mixture quite a bit -- like the old accelerator pumps, without
    which many engines would backfire and stall out if you punched it.
    Modern injected systems but still with mechanical throttles read the
    throttle position constantly, and if there is a fast change toward
    open, the injection duty cycle promptly dumps more gas in to
    compensate.
    .
    The Prius makes up for this by using battery current as the "first
    response", and letting the engine follow along as the total power
    demand is figured out -- with a slower, more economical opening of
    the throttle flap. Maybe not as much neck snap, but a heck of
    a lot more sensible...
    .
    _H*
     
  5. hyo silver

    hyo silver Awaaaaay

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    The Prius is so smooth and quiet, I don't ever want to go back. Any one who thinks it's noisy has never driven a muscle car. The water pump on my uncle's souped up Nova is louder than my Prius at full roar. Or would 'meow' be more appropriate?
     
  6. richard schumacher

    richard schumacher shortbus driver

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    Ditto me those decades with clutches, or as we now say, old broken-down-sh!t transmissions. It took me about three minutes to fall in love with the Way of the Prius. They can have my HSD when they pri-us it from my cold, dead fingers.
     
  7. richard schumacher

    richard schumacher shortbus driver

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    The lag is probably unavoidable; it needs that time to spin up and start the ICE.

    Hmm, maybe we need an "anti-EV" button, a switch that keeps the ICE running regardless so that it is immediately available for jumping off the line.
     
  8. richard schumacher

    richard schumacher shortbus driver

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    Anyone have contact info for Dave Hermance?
     
  9. Jonnycat26

    Jonnycat26 New Member

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    Or for planned passing.

    Honda has something similar on their CVTs... it's an "S" button which moves the engine into it's peak HP/torque range and holds it there.
     
  10. Paul R. Haller

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    Comming from a muscle car background, I like the road feel through your seat, ears and chest. There is nothing that can compare to you being pressed into the seat HARD by the torque of a big block, feeling and hearing the power while rocketting from a dead stop. I do miss it. That said however, I don't miss doing tune ups evey 7500 miles and the fuel bill now to drive one.
    I have to say that I do not like the VROOM with no boom. I always look to see if my tranny is behind me in my rear view mirror. It never is, but I can't stop thinking that somthing is wrong.
    I force myself to accept this as a condition of the "ring of economy". I also feel that real cars don't have hard plastic dash boards and hard plastic door panels. I'll live with it but I don't like it.
    I'm a techno geek. I love new and unusual technology. I am the first to also admit that I am a cheap SOB. The prius is a near perfect fit. NEAR perfect! What I really want is a 426 Hemi pumping out 400 horsepower, the feel of a 60s muscle car and 50 miles to the gallon topped off with GPS and a smart key system. I can deam. Until then, I'll have to live with 2 cars in the garage. A 2005 Prius and a 1970 GTO Ram air 455.
    -Paul R. Haller- :rolleyes:
     
  11. spwolf

    spwolf Senior Member

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    p.s. dont you love how articles blow everything out of proportions? Toyota is soooo concerned with CVT's, that they equipped new Rav4 in Japan with only 1 type of transmission.... CVT with "7 gears".
     
  12. Bill60546

    Bill60546 Member

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    I drove a clutch for 17yrs; 1980 Audi 4000 4 speed and 1989 Honda Accord SEI 5 speed, for ~250K combined miles and the Toyota CVT does not slip. I think its smooth as silk and one of the reasons I bought the Prius. I did test drive a Nissan Murado and liked the smoothness of their CVT, however, the rest of the car, well, its not a Toyota or a Honda.
    (I cant believe its been 25 yrs since I owned that Audi, jeeeeeesh!)
     
  13. NuShrike

    NuShrike Active Member

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    Isn't this a repost of an article that was posted back in October, or September? I remember seeing it before, and how Ford? was redesigning the CVT to emulate gear-shift torque kicks.

    Unsubstantiated is how I read it. Been driving a CVT since '96 and it's only been getting more manufacturer/model exposure and use rather than less.
     
  14. jbarnhart

    jbarnhart New Member

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    The "CVT" (power split device) is integral to the way the hybrid drive operates. There's no way Toyota would put a 5 or 6 speed in its place because they just don't do the job needed. The Prius needs three shafts, trannies have only two.

    On low-end torque... The electric motor used in the main drive of the Prius is capable of producing gear-cracking torque at stall. I suspect the output is carefully regulated by the computer to avoid damage and maintain economy. I don't doubt the Prius could lay rubber for a city block if the electrics were not torque limited. (Interestingly, the same is done in electric R/C cars, where the speed controllers are programmed to limit current to the motor to control wheelspin at take off.)

    If people are complaining about the "vroom" at high ICE revs, how about better engine mounting/balancing and acoustic insulation?
     
  15. Jack 06

    Jack 06 New Member

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    I doubt you could muffle that much engine noise when the engine jumps from 1,500 RPM to 4,000-4,500 RPM like that. And I think it's probably even more noticeable because the car is otherwise so quiet in non-high-rev driving. I just quickly got used to it.

    To me, what IS startling is to be looking at the MFD and seeing that efficient little four-banger suddenly sucking gas at 15 MPG on a big hill. But then you have to remind yourself that most cars do that, unnoticed.

    NuShrike--Newsweek may be guilty of recycling info that others have covered in a similar fashion, but they did print it this week.
     
  16. jfschultz

    jfschultz Active Member

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    23 years for me and I never looked back. In fact when I see those four rings on the road I tend to pity the poor guy.
     
  17. Danny

    Danny Admin/Founder
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    Sounds to me like GM is having to "dumb-down" their planned Saturn Vue CVT to match their planned customer base.

    Some people just can't "get" something that's different.
     
  18. Jack 06

    Jack 06 New Member

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    Sometimes I think those marketing people listen to too many focus groups. Really.
     
  19. bookrats

    bookrats New Member

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    Well... there is sex.

    :D
     
  20. spwolf

    spwolf Senior Member

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    I really dont think there is absolutly anything from with Prius's CVT. Sure it is a bit loud at acceleration but not annoyingly so. Otherwise, it is VERY quiet.

    However, there is a bit of point when it comes to "feel". Now, with Prius, it might not matter, but with faster hybrids it might. Thats is possibly why several sources have cited Toyota using 6 speed AT for their GS450h sedan, to provide better feel for the speed (and it should be amazingly quick). Dont forget that their new 6 speed AT's are industry best.
     
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