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GM releases some teasers for Volt 2.0

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by Ashlem, Oct 28, 2014.

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  1. john1701a

    john1701a Prius Guru

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    Here's what one of the die-hard enthusiasts had to say in response to the recent info from GM about the next-gen Volt:

    "GM has made the right decision in emphasizing more EV range, more responsiveness, and a more refined ride in CS Mode. They completely nailed what is important, thankfully tuning out the demand for higher but inconsequential MPG in CS Mode."
     
    #61 john1701a, Oct 30, 2014
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  2. hill

    hill High Fiber Member

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    That was a good read! Inside Ev's is suggesting "FIFTY" miles EV? Are they getting that from GM? Or is it that just a guess/number they pulled out of their bung - allbeit carefully calculated. If 50 EV miles was wispered to Inside Ev's from GM . . . . . I sure hope GM isn't back to their old ways of promising the moon; ah la this article claiming 230mpg:

    Chevy Volt Rated at 230 MPG in City Driving : TreeHugger

    [​IMG]

    because SOME prospective buyers are rightly insulted, when manufacturers think their sales audience is so dumb, that they can't remember back a few years ago .... or alternatively, the manufacturers claim, "oh ... you gota forget about the past ... we're not like that any more". we'll see. Heck, I'd seriously consider buying one DESPITE uncomfortableness for my 6'-5" frame trying shove the seat back all the way (wiping out any chance for the {2 only} back seat passengers).
    .
     
  3. austingreen

    austingreen Senior Member

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    [/quote]
    It is not a number from gm. The numbers from gm are that currently commuters get 80% of their daily drive in, and would be much happier with 90% or more. That suggests to me that gm is only saying 38x90%/80% = 43 aer as a firm commitment. If we take other information that when you include long trips 62.5% of trips are electric should go to 65%, electric is 5%-12% electric(103 mpge), CS is at least 5% more (39mpg) efficient we can can guestimate as a fleet we will go from about 60 mpge to 67 mpge. Your greenhouse foot print will very, and these are the minimum improvements from gms information. Inside ev is speculating that in janauary we will find out its better than gm is saying.

    Yep that guy is no longer there. The marketing chief at the time, Mr. Chevy run deep, was fired for accounting fraud (internal not public) and now is running first element along with dr. brown from UCI which is getting most of california's hydrogen money and a $7M loan from toyota.

    Well the did fire the guys most responsable and now one is part of the hydrogen lobby. I didn't see any lying in the current information at all. In fact they seemed to o there homwork and picked an ice that will be quite like the one in the next gen prius. Ofcourse full details will be available a year from now, with most of them in January.
     
    #63 austingreen, Oct 30, 2014
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  4. Jeff N

    Jeff N The answer is 0042

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    No, I'm pretty sure they did the numbers themselves. If you look down in the comments section, I pointed out to them that the new pack has the same configuration as the 2015 Spark EV which has 19 kWh. Jay Cole updated the article with that angle after reading my comment.

    GM has hinted that the new pack will use a slightly wider SOC window. The existing 2015 Volt (and ELR) use about 68-69% on 17.1 kWh. Unlike your implication that GM exaggerates their specifications, they haven't updated the EPA window sticker EV since 2013 although the battery has gone from 16.5 kWh to 17.1 kwh and the SOC window has gone from 65% to 68-69%.

    If you assume they will use 70% of the new battery and you scale things based on the 2013 model year EPA estimate you get about 46-47 miles up from 38. Now adjust that for the efficiency improvements in the new motors and new inverter design and 50 seems like a reasonable guess although, as they article stated, it could be a few miles lower or higher. If I were driving it I would probably get closer to 65 miles of range.

    This is speculation so we will have to wait until January for all of the official numbers.
     
  5. john1701a

    john1701a Prius Guru

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    That in itself is speculation. We have only been told lots of detail will be revealed in January. There hasn't been mentioned of official numbers being part of that.
     
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  6. Jeff N

    Jeff N The answer is 0042

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    That's just someone's guess about CS Mode (hybrid mode) mpg on the new engine and transmission. We all know here that the Prius went from 1.5 to 1.8 liters and made significant mpg gains. The Volt may get similar relative improvements moving from 1.4 to 1.5. The new engine is part of a newly redesigned engine family and now has direct injection, EGR, 19% higher compression, wider dynamic valve control, and runs regular gas instead of premium.

    The transmission has also seen a major redesign with a new physical layout, new motors, and some type of change to the clutch and planetary arrangement that has not yet been fully described.

    I'm guessing the highway EPA rating will be at least 42 (from 40) and I'm guessing they will make bigger improvements on the city estimate which notably lagged the city/highway ratio typically seen in other full hybrid cars.

    This will let them exceed Ford's Energi hybrid mpg but with similar or better acceleration performance vs Energi in hybrid mode (and much better performance vs Energi EV mode) and well over twice the EV range.

    Are they going to match Prius hybrid mpg. No (but who else does?). But with further increased EV range, the 2016 Volt will be using its gas engine an even smaller overall percentage of the time meaning reduced total gasoline consumption.

    I'm not making a prediction and I don't know enough about transmission design to be sure about my preconceptions, but...

    I wouldn't be shocked if the new transmission is essentially the same as the Ford/Toyota design with the wheels and large MG on the ring gear, smaller MG on the Sun gear, and engine on the planetary carriers -- except that they add a clutch to disconnect the engine and a clutch/brake to lock the planetary carriers to the transmission case. Doing this gives them the simplicity advantages of the Prius design in that they would primarily change the clutch engagement when switching from EV to hybrid mode instead of more frequently while driving at different speeds in both modes.

    In EV mode, they could now additively use the two motors together under high torque demand at vehicle speeds below the peak smaller MG RPM limits with the carriers locked. In Volt 1.0 they can only spread the rpms across both motors under low torque demand for efficiency. At higher speeds (above 60-70 mph?) they could release the planetary carrier brake so it can free spin and just drive using the larger MG with the smaller MG only energized enough to keep the Sun and planetary carrier RPMs within limits.

    In hybrid mode, they would release the planetary carrier brake and clutch-in the gas engine thereby making it identical to the Prius-like arrangement which will get rid of series mode entirely (except while the vehicle is stopped) and allow them to drive at speeds under ~35 mph with gas engine on in the more efficient series/parallel configuration thereby bringing up their city EPA mpg to 42+ from 35.

    Doing this may hurt the EV mode highway efficiency slightly because they will no longer be able to share the load across both electric motors at high speed but no other EVs do that today so it's no loss versus the competition (Tesla, LEAF, etc. which use a single motor at high speeds).

    It also lets them drop from 3 clutches (2 clutches and one clutch/brake) by eliminating a clutch. It is rumored that Volt 2.0 did eliminate a clutch. Or, maybe it's possible to add a clutch to allow the larger MG and output to the differential to be detached from the ring gear to avoid the friction of free spinning the Sun and carriers during high speed EV. do not know whether that clutch design is practical.

    I think this is also where Toyota will go in the future when they have large enough battery packs (high enough peak kw output) to enable an EREV configuration.
     
    #66 Jeff N, Oct 30, 2014
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  7. austingreen

    austingreen Senior Member

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    GM gave us some details and a video. There are now two clutches insead of 3. My guess is serial mode or single motor EV is one cluch configuration, Dual motor ev a second clutch configuration, and prius like hybrid 2 motor psd the thrid configuration. The hood up of the psd is probably the same as gen I volt but gear counts may be different, this is a different psd configuration than ford or toyota and may be better for high speeds worse for low speeds where serial mode may be chosen by the volt software. It is likely that the ice attached to wheel mode is engaged at lower speeds than the gen I volt, but this is pure conjecture on my part.

    This should give the volt an advantage of lower friction during EV mode which if GM did its homeword right will be engaged 90%+ of the time for daily driving. The charge sustain mode should be at least 5% more efficient becuase of the new more efficient ice with better nvh and lower weight(GM).
     
  8. Jeff N

    Jeff N The answer is 0042

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  9. austingreen

    austingreen Senior Member

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    +1
    That is new information, and we will have to wait until January or maybe even launch to find all the details.

    I am sure there is too much in the motor trend piece that the haters will key off. Remember that isn't from gm
    Remember there promise is some of these assumptions are wrong. My best guess for what gm is actually promising before they are done is at least 43 aer. I don't expect epa numbers until right before the car is released but we should get a better ball park in january when we know how large the battery is. I am sure gm will be playing with SOC until the last minute, but the more powerful ice means that they can allow the battery to drop to a lower SOC without worrying about the power being needed. Inside Evs guess of 19kwh seems more reasonable to me, and even that is a guess until gm tells us something. Other cool information or opinons from motortrend.

    Key is though the redesign is more radical than the prius, it isn't as likely as important. The prius body changed radically which gave it looks that while some didn't like, actually appears to have not only boosted fuel economy but increased sales. The acceleration went from unacceptable to may to acceptable. The volt already had acceptable acceleration, now it probably has good acceleration. No one knows the body and seating changes, but I doubt its as big as the prius. That is why I don't think the volt will get a huge boost in sales. It may get to 30,000 or 40,000 /year in the us though, and GM may put voltec in a more popular body style.
     
  10. Jeff N

    Jeff N The answer is 0042

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    It took me a couple of attempts to parse out the details from GM's patent. It really helps to click the upper right button to download the PDF version and then print it out single-sided. That way you can follow the text while looking at the illustrations.

    The bottom line is that the first planetary gear set is identical to a Prius or Ford hybrid transmission. The big motor and wheels (via the differential) are connected to the ring gear. The smaller motor is connected to the Sun gear. The input torque comes in on the planetary carriers.

    The part that is different from Toyota/Ford is that the engine is connected to the second planetary gear set through its planetary carriers but there are 2 clutches which can connect either or both of the planetary carrier or the Sun gear to the engine input of the first planetary gear set (at its planetary carriers) instead of just directly connecting the engine to the first planetary gear set carriers. Doing this allows the engine to be connected either at a 1:1 ratio or at a fixed overdrive ratio under different driving speeds and conditions. They can also engage both clutches at the same time with the engine off which has the effect of holding the planetary carriers still.

    So, it's a "Prius" transmission but with an additional fixed gear ratio option between the engine and the power-splitting planetary gear set but it can also hold the engine still so it allows for the 2 electric motors to be additively used for transmitting torque.

    We don't know if this is the Volt 2.0 transmission design but it sure seems like a good possibility.
     
    #70 Jeff N, Oct 30, 2014
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  11. Trollbait

    Trollbait It's a D&D thing

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    There was once going to be a FWD 2-mode hybrid. Is this it, or descended from it?
     
  12. Jeff N

    Jeff N The answer is 0042

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    This is not the 2-mode FWD transmission. It's been a long time since I read the 2-mode patent so I can't say offhand how it's different but there are probably some similarities. I'll go back and read 2-mode again to remind myself how it relates to this new one.
     
  13. austingreen

    austingreen Senior Member

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    We won't know for sure what it is until January or Feb. It may be this recent gm patent but it could even use some toyota or ford patents as protection has now expired for some. The paice patents expired in 2012, so no problem using those. Lawyers were involved in last minute decissions last time, and they decided that gen I volt's software didn't violate toyota or ford's patents, this time gm may be using something from these old patents if they are better than in gen I. That is just specualtion on my part. It sounds like the engineers were more in charge of this design than lutz and gm lawyers, and many things have changed.
     
    #73 austingreen, Oct 30, 2014
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  14. KV1955

    KV1955 Member

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    This is a really interesting thread. I have another 18 months on my PIP lease, and a 50-mile range Volt will sure attract my attention...even though I really love the useful hatchback configuration of the Prius.
     
  15. john1701a

    john1701a Prius Guru

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    Interesting, you bet.

    We were told to expect much, for the next-gen design to leap-frog the competition... which would be great, considering what was needed.

    Instead, we're finding out the improvements are incremental and are already seeing downplay.
     
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  16. F8L

    F8L Protecting Habitat & AG Lands

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    No worries on the usefulness. The Volt is also a hatchback with flat folding seats. You do lose some space,however, and there is a lip from the bumper leading to the inside of the hatch vs. the flat opening in the Prius. This hasn't hurt me In any way and I can still roll out a sleeping bag and sleep in the hatch. I'm 6'3" too.
     
  17. telmo744

    telmo744 HSD fanatic

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    Thank you for the link, Jeff. (y)

    Right on the first sentence, the "Some 69,000 of what marketing director Steve Majoros describes as “the happiest owners on earth” have already racked up 650 million electric miles on their Chevy Volts, and the 2011 model currently ranks tops in class on J.D. Power’s Dependability index."
    Is there any source to this? Michael Karesh True Delta site shows Volt as average in class trip reports... :whistle:
     
  18. Jeff N

    Jeff N The answer is 0042

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  19. telmo744

    telmo744 HSD fanatic

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  20. Jeff N

    Jeff N The answer is 0042

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    TrueDelta doesn't list the 2011 Volt. I filled out their survey but apparently they don't have enough owners for that model year.

    There is no real doubt that Prius reliability is better (as usual for Toyota). The Volt problems, as far as I know, tend to be easily correctable as opposed to major component failures requiring replacement of expensive parts.

    The new CR survey data is available now. Volt owner satisfaction slipped from 91 to 85. Prius is 82 and PiP is 69.

    image.jpg image.jpg
     
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