2020 Hyundai Elantra Gains Efficiency Thanks to All-New CVT

Discussion in 'In the News' started by xcel, May 18, 2019.

  1. litesong

    litesong litesong

    Glad to hear the fake shifts don't occur, except at harder accelerations. I hated it, when I first heard about fake shifts. Under hard acceleration, the fake shifts must increase 0 to 60MPH times..... & I might think, lessen CVT reliability? My 2007 Dodge Caliber with CVT only had a 2000RPM at 60MPH range. Even at that, the Caliber came with a low setting for the CVT.
     
    Last edited: Jan 8, 2020
    BillLin and xcel like this.
  2. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Here in Illinois , we have ( don't laugh ) HILLS. I don't go at a steady 60 MPH ever ,
    but at 55 MPH , my RPM will be between 1400 and 2200. If memory serves.
    Yota feels there is no need for a tach , and my SG crapped out a few years ago.
    In my experience , a CVT will vary RPM a LOT . depending on hills and wind.
    Another good reason to have a manual transmission.
     
    RedylC94, xcel and BillLin like this.
  3. litesong

    litesong litesong

    My experience, too. Two things blur my knowledge tho. I had a less expensive Dodge Caliber with CVT (which I really wanted to experience), that didn't have a tachometer. Also, the engine was very smoothly quiet, & engine noise was masked by road & wind noise. Therefore, I could only determine in a very rough way, the rpms pushing through the CVT. Once tho, I was on a day trip to eastern Washington(known for lots of wind). Moving eastward downwind (steady winds at 20MPH(?) to 30+MPH(?), my gas gauge seemingly fell very slowly, indicating low rpms & high MPG. At one point I traveled north experiencing crosswinds & an increasing drop in the gas gauge. At another point, I turned westward, directly into the eastward wind. My gas gauge REALLY starting falling. Again, it was hard to hear the engine, but I could feel my foot was pressing the gas pedal fairly hard to maintain speed. I slowed down trying to reduce the wind effect. I suspect, if I had had a tachometer, I would have been flabbergasted by the rpms.
    Altho I did love the CVT in our Caliber, it wasn't a mistake that our next car had a manual transmission & we have never had another CVT.
     
    Last edited: Jan 8, 2020
    xcel and BillLin like this.
  4. RedylC94

    RedylC94 Well-Known Member

    Those can't be very serious hills if you can maintain 55 mph at only 2200 RPM.

    How could the CVT NOT allow engine speed to vary a lot, if it's going to pick the most fuel-efficient ratio for widely varying conditions? Remember the Prius engine produces (or is allowed to produce) a lot less torque at moderate engine speeds in proportion to the mass of the car than most cars you've driven with manual transmissions---even including the Mazda, by a wide margin. As a result, more engine revolutions are necessary to get up a hill. There's no way around that math, no matter how the transmission is programmed.
     
    xcel and BillLin like this.
  5. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    I didn't say they were serious hills. :)
    I understand how the CVT works. I was just pointing out that trying to calculate RPM
    for a given speed is pointless , since the tiniest change in load will cause revs to rise or fall.
    And as you know , the Prius is definitely lacking in the torque department.
     
    xcel and BillLin like this.
  6. Trollbait

    Trollbait Well-Known Member

    Prius doesn't have a true CVT, and has an electric side to draw upon. Depending on the charge in the battery, MG2 can provide more work, allowing the engine rpms to stay low.
     
    EdwinTheMagnificent, BillLin and xcel like this.
  7. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    That is correct , Trollbait.
     
    BillLin and xcel like this.
  8. RedylC94

    RedylC94 Well-Known Member

    That might depend on what "true" means. It's not "true," only in the sense that some of the power from the engine doesn't take a purely mechanical route to the wheels. In most---obviously not all---circumstances, most of the power MG2 sends to the wheels to climb a hill comes to MG2 from the engine (indirectly via an electrical detour through MG1 and the inverter), not from the battery. Combined with the comparatively low engine torque at moderate engine speeds, that's why on an uphill, or accelerating, it distinctly does NOT "[allow] the engine rpms to stay low," compared even to a very modestly powered manual-tranmission car such as the 1981 Mazda GLCs Edwin and I had. The times when the e-CVT does indeed save fuel by allowing engine speed to stay especially low are times of low power demand, e.g., level-road cruising. Of course engine speed can be zero on downhills or maneuvering at very low speeds.

    To pursue the example comparison with the old Mazdas more specifically:
    Torque of 2010 Prius at 4000 RPM (its peak), according to "Operating Line" plot published by Toyota: 104 ft-lb
    Torque of 2010 Prius at 3000 RPM, according to "Operating Line" plot published by Toyota: 74 ft-lb
    Torque of 1981 GLC 1.49L engine at 3000 RPM (its peak), according to Mazda: 82 ft-lb.

    3350 lb/74 ft-lb = ~45 pounds per foot-pound for the Prius
    2150 lb/82 ft-lb = ~26 pounds per foot-pound for the GLC
    That's why the Prius engine has to spin a lot faster than 3000 rpm to climb a steep hill the Mazda could climb at the same road speed at 3000 rpm---unless the Prius battery is contributing more power than it possibly can more than very briefly. The difference would be even greater for most newer manual-transmission cars, which generally offer much more power than the old GLC.
     
    EdwinTheMagnificent, BillLin and xcel like this.
  9. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    RedylC94 , you have a very good understanding of the Prius , and can certainly explain it well.

    We do have "hills" in NW Illinois , between Freeport and Galena/Dubuque. I don't get out there
    very often , but I have been there in the Prius , when my Scangauge was working.
    Unless I built up considerable speed (70 in a 55) going downhill , I needed a good 3000 or so RPM to climb the next hill.

    This lack of torque has me thinking about a modern non-hybrid manual trans car , at least for highway use.
    It's REALLY hard to beat the Prius as an urban/suburban transportation appliance.
     
  10. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    So what if it revs to 3k to top off a hill? I doubt you would give up that easy 50 MPG highway run in the Prius in exchange for the maybe 40-45 MPG highway ICE car, and let's not even think about the rest of the time... :) When it is time for your new car, I suspect you'll go for the next better hybrid. I don't quite see you in a BEV, but who knows. :)
     
  11. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    More likely a PHEV than a BEV , but...…….. really , who knows. It's not like I really NEED
    a new car. I did kinda promise the Prius to my youngest daughter , about a year from now.
    But a manual trans ICE car would be a fun 2nd car , if I could justify tit.
     
    xcel and BillLin like this.
  12. litesong

    litesong litesong

    Who here can spell the word, "ticket" or "ticet" or "tiket"? My old Dodge Caliber had a low setting on the CVT. It was nice, at times.
     
    BillLin and xcel like this.
  13. litesong

    litesong litesong

    Everyone can justify, "tit".
     
    BillLin and xcel like this.
  14. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    I wasn't touching that one. :D
     
    xcel likes this.
  15. litesong

    litesong litesong

    You're not getting a LIKE from me.:D:D
     
    BillLin and xcel like this.
  16. RedylC94

    RedylC94 Well-Known Member

    Thanks! Many people (not you!) have strange misconceptions about how a Prius manages energy. I can grasp the basic physics involved, although not the mysterious programming details or the inner workings of the inverter.

    According to the published "Operating Line," at 3000 rpm you were using a whopping 42 horsepower (31.6 kw) to climb that hill, under 44% of the claimed peak power. At the same speed, the old Mazda, with its more conventionally shaped "torque curve," provided 69% of its maximum power.

    A little less off-topic for this thread, I wonder whether the Elantra in question has to rev up so much to climb a hill. Some of the complaints people have with both mechanical CVTs and e-CVTs allowing allegedly excessive engine speeds are unfair, because the same engine in the same car with any other type of transmission would have to rev up almost as much to achieve the same results. ("Almost," because of losses.)
     
    BillLin likes this.
  17. litesong

    litesong litesong

    We have both a 6 speed 2013 automatic & a 6 speed 2016 manual Elantra. On flatland highways we have no problem keeping rpms down even on moderate highway hills with no hill causing the automatic to shift below 5th gear. Of course, the 6% lower geared manual Elantra never needs shifting down. There is a 50MPH country road with a very steep hill, that I pre-select before the hill, 4th gear & it goes right up the hill, maybe over 2500rpms, but I don't think 3000 rpms. The manual Elantra, only needs 5th gear to ascend the hill. On 4061 foot high Stevens Pass, here in Washington state, the automatic Elantra likes 4th gear to reach the Pass top, using 2500rpms, but I don't think 3000rpms. The manual needs only 5th gear, & that with no strain (& below 2500rpms?) & two people.
     
    Last edited: Jan 15, 2020
    BillLin and xcel like this.
  18. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    My spelling is impeckerable , but my typing is weak.
     
    xcel, litesong and BillLin like this.
  19. litesong

    litesong litesong

    Now I join Bill, & won't touch that........
     
    xcel and BillLin like this.

Share This Page