Sep 27

GM Patent Application May be for the Chevrolet Volt’s Transmission

 

[ad#post_ad]It seems very likely that the GM patent application “Output Split Electrically-Variable Transmission with Electric Propulsion Using One or Two Motors” describes the Chevrolet Volt transmission (which GM has called the Electric Drive Unit). The file is a pdf and you’ll need the free Adobe reader to view it:

http://www.freepatentsonline.com/20090082171.pdf

Here is a snapshot of the title page:

I will apologize in advance to those of you who are less technically inclined. This posting contains a lot of engineer speak. I’ve tried to keep it as straightforward as possible, but this is a complex device. If you want help understanding how a planetary gearset works here is a link to help:

http://auto.howstuffworks.com/automatic-transmission2.htm

Figure 1 of the patent application is here:

It shows the internal combustion Engine connected via clutch C3 to Motor/Generator A which connects via clutch C2 to the Ring gear (labeled C) of a planetary gearset . The Ring gear also connects via clutch C1 to a stationary member of the transmission case. Motor/Generator B is connected to the Sun gear (labeled A) of the planetary gearset. The planet Carrier (labeled B) of the planetary gearset is connected to the Final Drive which, though this is not shown, is connected through the differential to the drive wheels of the car. (Don’t worry about the second, dashed, copies of Engine and M/G A, they just show an optional alternative configuration without clutch C3.)

The nature of a planetary gearset is that when the speeds of any two of the Ring, planet Carrier, and Sun gears are known the speed of the third is determined.

Figure 3a of the patent application is here:

It shows a truth table defining the available operating modes of the transmission. In the first three columns C1, C2, and C3 there is an X when that clutch is engaged or a blank when that clutch is disengaged. The rows of the table define six operating modes (plus a seventh, transition, mode).

In mode 1: 1 Motor Electric-only the Ring is held stationary and there is a fixed gear ratio from M/G B to the Final Drive.

In mode 2: Series we still have the fixed gear ratio from M/G B to the Final Drive. In addition, the Engine is connected to M/G A so that M/G A can start the Engine and the Engine can then drive M/G A to generate electricity for the battery and/or M/G B.

In mode 3: Output Split the Engine and M/G A work in unison to drive the Ring gear. This torque is blended with that from M/G B to the Final Drive. (This mode is just like the Toyota Prius’s Hybrid Synergy Drive.) Note that GM seems to have stated that the Volt never mechanically couples the Engine to the wheels. That would imply that mode 3 is never selected in the Volt, even though it could be. I don’t know what GM has really done in the Volt. We will presumably find out by the time the first Volts are delivered to dealers.

In mode 4: Neutral the Final Drive receives no torque since the Sun gear can spin freely.

In mode 5: Neutral / Battery Charge the Final Drive receives no torque, but the Engine is attached to M/G A and can drive M/G A to generate electricity for the battery.

In mode 6: 2 Motor Electric-only M/G A and M/G B are driven simultaneously and their torque is blended for delivery to the Final Drive. The combination of speeds of M/G A and M/G B determines the speed of the Final Drive. Alternately put, the speed of M/G A determines the gear ratio from M/G B to the Final Drive. This is the Electrically Variable Transmission (EVT).

You may ask how these six modes relate to the Charge Depleting (CD or Electric) mode of the Volt and to its Charge Sustaining (CS or Extended Range) mode. Here is my take:

In CD mode the 1 Motor Electric-only and 2 Motor Electric-only modes are used to optimize the electrical efficiency of M/G A and / or M/G B at the required road speeds. It is all about using the EVT to get the most miles of All Electric Range from the charge available from the battery. No gas is used.

In CS mode the Series mode is used to have the Engine, over time, drive M/G A to generate just enough electricity to keep the battery state of charge within the buffer range while M/G B is driving the wheels through the fixed gear ratio when the Ring gear is held stationary. As I said earlier, the Output Split mode could be used in CS but GM may have chosen not to do this for some reason.

Of course, there is no proof that the Volt’s transmission is what this patent application describes, but the timing (filed September 10, 2007) is right and it fits the statement by GM public relations guy Rob Peterson that the Volt has a planetary gearset and a number of clutches. It also fits the statements Volt powertrain engineer Alex Cattelan made in her interviews with Lyle last November: http://gm-volt.com/2009/11/09/engineering-design-of-the-chevy-volts-two-electric-motors/ . And there is NASAman’s statement from Bob Lutz that “the Volt will have a transmission like no other” In addition, several people who’ve ordered Volts have posted the following description from the myvolt.com order tracking site:

“Powertrain
TRANSMISSION AUTOMATIC, ELECTRONIC RATIO SELECT, GM, STRONG HYB RID, EVT, PLUG IN
ENGINE FLEXIBLE FUEL, (GAS/ALC), 4 CYL, 1.4L, MFI, DOHC E-FLEX, FAM 0″

In conclusion, if the patent application does describe the Volt’s transmission it means that the Volt is NOT a single speed only transmission. It is an Electrically Variable Transmission (EVT). In addition, if the clutches C2 and C3 are engaged simultaneously there is a mechanical power path from the engine to the wheels. It may be that GM has chosen to never engage C2 and C3 simultaneously, but they could if they wanted to. (I don’t know if that would be an infringement of Toyota’s Hybrid Synergy Drive patents; I’m an engineer, not a patent lawyer.)

For more discussion of this patent see the following thread in the Engineering forum:

http://gm-volt.com/forum/showthread.php?p=43109#post43109

Lyle tells me GM has said it plans to publicly unveil this system soon after the cars are out there, so we should get a definite resolution of all these questions by then. In the meantime it sure is fun to speculate.
[ad#postbottom]

This entry was posted on Monday, September 27th, 2010 at 7:13 am and is filed under Engineering. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

COMMENTS: 135


  1. 1
    kdawg

    +8

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Sep 27th, 2010 (7:27 am)

    I love the detailed engineering posts.. keep em coming.


  2. 2
    ziv

    +2

     

    Vote -1 Vote +1

    ziv
     Says

     

    Sep 27th, 2010 (7:29 am)

    Nice find, Rick but my initial response is, WHAT? The ICE is connected by a clutch to the generator which is connected to the ring gear of the planetary gearset which is connected by a clutch to a stationary member of the transmission case? What I can’t figure out is what a stationary member is and whether this is in fact a near direct linkage between the ICE and the drivetrain, which I thought that GM had ruled out.
    More importantly, what is the probably effect of this on the efficiency in CS mode? In CD mode?
    Sorry to be so obtuse, but I had thought I understood the interaction between the ICE and the genset but this is substantially different than I envisioned.
    Interesting days.


  3. 3
    JohnK

    +1

     

    Vote -1 Vote +1

    JohnK
     Says

     

    Sep 27th, 2010 (7:32 am)

    “at least one electric only forward operating mode”. Kind puts to rest the direct drive from the ICE issue. And the “not truly a serial hybrid” question.


  4. 4
    JohnK

    +1

     

    Vote -1 Vote +1

    JohnK
     Says

     

    Sep 27th, 2010 (7:46 am)

    OK, correction to post #3 – it doesn’t put anything to rest. Sorry about that.


  5. 5
    ziv

    +1

     

    Vote -1 Vote +1

    ziv
     Says

     

    Sep 27th, 2010 (7:46 am)

    Scratch the question about CD mode, talk about a clueless question…


  6. 6
    Dave K.

    +2

     

    Vote -1 Vote +1

    Dave K.
     Says

     

    Sep 27th, 2010 (7:47 am)

    An interesting system. Will be good to hear from the many engineers that frequent this site. I expected a simple in-line two collar system. One collar being fixed at three tuned rpm set points. The other being variable to match the demand of the accelerator. With both collars being fixed during mountain mode.

    =D-Volt


  7. 7
    Jim

    +6

     

    Vote -1 Vote +1

    Jim
     Says

     

    Sep 27th, 2010 (8:02 am)

    WHAT???, This is not anywhere close to the drive train I have been reading about for the last 3 years. We have heard it many times from Lyle’s post that the ICE is in now way connected to the wheels. This looks like a patent for a strong hybrid not the simple Voltec design that makes it so appealing.

    [ICE]===[Generator]——[Battery]—–[Power Control]—-[Drive Motor]====[Wheels]

    ==== Mechanical drive shaft
    ——- Electrical Wires

    This is going to confuse alot of people.


  8. 8
    carcus3

    -6

     

    Vote -1 Vote +1

    carcus3
     Says

     

    Sep 27th, 2010 (8:04 am)

    Maybe this is why GM hasn’t released the mpg — they’re still waiting on the lawyers to tell them whether the Volt will be configured as a series hybrid or a series/parallel hybrid.

    /sure sounds a lot like HSD to me


  9. 9
    Right Lane Cruiser

    +3

     

    Vote -1 Vote +1

    Right Lane Cruiser
     Says

     

    Sep 27th, 2010 (8:06 am)

    Very interesting! This leaves room for tweaking by GM and also smooths the path for different “generator” types (NG, Hydrogen, Diesel, more batteries?) through “simple” software upgrades to operational parameters. Planned modularity is a powerful concept and one GM should exploit to the fullest.

    The patent infringement question is the one that most worries me. Perhaps GM can reach a settlement with Toyota if this is in fact an issue. That is what Ford did. (Contrary to what appears to be popular opinion, Ford and Toyota eCVT units were developed separately and Ford does *not* license the tech from Toyota. Interestingly, both are derivative works of the PNGV – http://en.wikipedia.org/wiki/Partnership_for_a_New_Generation_of_Vehicles – program concept powertrains.)


  10. 10
    ziv

    +3

     

    Vote -1 Vote +1

    ziv
     Says

     

    Sep 27th, 2010 (8:11 am)

    Jim’s diagram, with one exception, is what I thought the drive system would look like. The only thing I think might be different is that the output from the generator would flow through a splitter with the electricity going straight from the generator to the power control device to avoid efficiency losses, with the balance of the extra electricity flowing from the generator to the battery when the generator is generating more power than the car needs. When the car is accelerating and needs more power than the genset is supplying the additional power is drawn from the battery.
    Or so I thought…

    Jim: WHAT???, This is not anywhere close to the drive train I have been reading about for the last 3 years. We have heard it many times from Lyle’s post that the ICE is in now way connected to the wheels. This looks like a patent for a strong hybrid not the simple Voltec design that makes it so appealing.[ICE]===[Generator]——[Battery]—–[Power Control]—-[Drive Motor]====[Wheels]==== Mechanical drive shaft
    ——- Electrical Wires .  


  11. 11
    bitguru

    +1

     

    Vote -1 Vote +1

    bitguru
     Says

     

    Sep 27th, 2010 (8:14 am)

    edit: I posted something trying to find a use for the “transition” mode, but it didn’t make any sense so I have redacted it.

    (But when the ICE is off, C3 can closed to use M/G A as a starting motor.)


  12. 12
    Rob

    +42

     

    Vote -1 Vote +1

    Rob
     Says

     

    Sep 27th, 2010 (8:20 am)

    Sighted this morning on eastbound I-94 outside Ann Arbor: a car hauler loaded with Chevy Volts! They all sported the white plastic protective film you see nowadays on vehicles en route to dealerships . . .


  13. 13
    kdawg

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Sep 27th, 2010 (8:26 am)

    So M/G B is always connected to the planetary gearset. Even in nuetral.


  14. 14
    Robert

    +1

     

    Vote -1 Vote +1

    Robert
     Says

     

    Sep 27th, 2010 (8:29 am)

    Very nice Post,
    This really makes me think GM is developing the most advanced cars out there, it could be that the transition to output split mode was just too rough and they decided not to use it, I would think transitioning between these differant modes would be the tricky part.
    And you dont want to engage all 3 clutches at the same time.
    But whats the second engine for? I cant figure how that would improve things, adding a second engine and third motor, just seems like more weight.


  15. 15
    JackA$$

    +1

     

    Vote -1 Vote +1

    JackA$$
     Says

     

    Sep 27th, 2010 (8:30 am)

    Rob, it would have been great to have a pic…. even from your phone. NPNS!


  16. 16
    herm

    +2

     

    Vote -1 Vote +1

    herm
     Says

     

    Sep 27th, 2010 (8:31 am)

    Rob: Sighted this morning on eastbound I-94 outside Ann Arbor: a car hauler loaded with Chevy Volts! They all sported the white plastic protective film you see nowadays on vehicles en route to dealerships . . .

    Must be dealer demo models, either that or important people back east are getting theirs… Lance Armstrong will take delivery of the first LEAF this week.. I think that beats GM to the market or maybe not, depending on what happens to this shipment.


  17. 17
    Neromancer

    -1

     

    Vote -1 Vote +1

    Neromancer
     Says

     

    Sep 27th, 2010 (8:32 am)

    Jim: WHAT???, This is not anywhere close to the drive train I have been reading about for the last 3 years. We have heard it many times from Lyle’s post that the ICE is in now way connected to the wheels. This looks like a patent for a strong hybrid not the simple Voltec design that makes it so appealing.[ICE]===[Generator]——[Battery]—–[Power Control]—-[Drive Motor]====[Wheels]==== Mechanical drive shaft——- Electrical WiresThis is going to confuse alot of people.  (Quote)

    I’m afraid that has long ago been dismissed on how the Volt works.

    GM has stated that the generator can also act as a drive motor. The generator can be used to drive the car. Also the main drive unit can be used for regen. The generator is connected to the battery but is also directly connected to the power control (as only residual energy charges the battery).

    The ICE does have a potential mechanical path to the wheels but through the generator. I’m not sure how much in losses would be endured by running mechanical power through the generator. Perhaps this is why GM doesn’t use this option. Also maybe this mode is less efficient on the ICE.


  18. 18
    Randy

     

    Vote -1 Vote +1

    Randy
     Says

     

    Sep 27th, 2010 (8:33 am)

    Not exactly on subject but just read another Peak OIL article and this one is really scary , I dont think they can get these volts out the door fast enough. At least once they start production ,they can always ramp up (to a certain extent) if Gas prices go nuts which i suspect they will in the near future. Check out the link.

    http://www.lifeaftertheoilcrash.net/


  19. 19
    Flaninacupboard

    +1

     

    Vote -1 Vote +1

    Flaninacupboard
     Says

     

    Sep 27th, 2010 (8:33 am)

    As soon as they said “two motors” some time ago it was obvious it would be a CVT in there. I am going to call it that the engine IS engaged to the wheels. why am i so sure?

    In CD mode MG1&2 work in tandem (via C2) as a CVT to get the best efficiency from the two motors. It’ll feel like the prius.

    In CS mode if C2 is -not- engaged you’ll be in mode one with a single speed transmission. Suddenly your response is completely different, and it would not be a great drive. You have to engage C2 to allow the CVT to work, and then you’re in power split. In one way this is good news, CS MPG would be a ton better with power split. in another it’s bad, it’s not what i thought the Volt was…

    I don’t -think- this infringes toyota’s IP because of the cluthces. Toyota’s system is still better (for efficiency) because of the losses involved with the clutches.


  20. 20
    Pat Joy

    +10

     

    Vote -1 Vote +1

    Pat Joy
     Says

     

    Sep 27th, 2010 (8:36 am)

    This has to be a patent for the two mode hybrid drive for GM cars and trucks, not the Volt!

    P


  21. 21
    Flaninacupboard

    +1

     

    Vote -1 Vote +1

    Flaninacupboard
     Says

     

    Sep 27th, 2010 (8:37 am)

    kdawg: So M/G B is always connected to the planetary gearset. Even in nuetral.  (Quote)

    Yep, same as Prius.


  22. 22
    carcus3

    +2

     

    Vote -1 Vote +1

    carcus3
     Says

     

    Sep 27th, 2010 (8:41 am)

    Flaninacupboard: I don’t -think- this infringes toyota’s IP because of the cluthces. Toyota’s system is still better (for efficiency) because of the losses involved with the clutches.  

    My impression as well — the clutches are the only thing that really stands out as a major difference between GM’s patent application and Toyota’s HSD.


  23. 23
    herm

    +6

     

    Vote -1 Vote +1

    herm
     Says

     

    Sep 27th, 2010 (8:43 am)

    This is a modified and simplified 2 Mode transaxle that GM has in their parts bin.. but the most important part is that they get to reuse most of the software that goes with that transaxle.. with the goal of extracting the highest possible electric range out of the least battery possible. GM designed the Volt at a time when lithium batteries were more expensive and their life was unknown.. thus this added expense was the insurance to get the 40 miles of range and still have the batteries last 10 years or longer.
    GenII Volts may just swap this transaxle for a simpler two motor setup with a slightly bigger battery and still achieve the 40 miles of range.. or perhaps mass production of the expensive 2 Mode transaxle will lower the cost to the benefit of other cars that GM has waiting on the wings.

    We recently learned of the 80% brake regen efficiency, a world record, and the 50 miles of AER.. both of these are the results of this device.

    Gen I Volts may end up being the most sophisticated and over-engineered ones of the series.


  24. 24
    CorvetteGuy

    +7

     

    Vote -1 Vote +1

    CorvetteGuy
     Says

     

    Sep 27th, 2010 (8:46 am)

    It looks like a lot of chum in the water for the trolls, assuming they can understand all that. It looks to me like there will be a lot of toggling between clutch C2 and C3. We have been told that in CS Mode, that the engine will run at one of several different RPMs based on electricity need at the time, and that is unrelated to vehicle speed. If C2 and C3 were to engage together, first of all you could ‘feel it’, and we have seen video of it coming online and it was ‘imperceptible’. So, from a standing start, both electric motors are engaged to the wheels, but when the ICE comes online, one of them is disengaged and starts to generate electricity. So, in stop and go traffic, it would toggle back and forth based on how much power is needed to the wheels. Is that about right?


  25. 25
    omnimoeish

    +1

     

    Vote -1 Vote +1

    omnimoeish
     Says

     

    Sep 27th, 2010 (8:50 am)

    Is it possible this is the system that GM was planning on using in their plug in hybrids? ie plug in Saturn Vue which got turned in to a plug in Buick, which got shelved for a later and still unknown model yet to be announced?


  26. 26
    herm

    +3

     

    Vote -1 Vote +1

    herm
     Says

     

    Sep 27th, 2010 (8:51 am)

    Flaninacupboard: I don’t -think- this infringes toyota’s IP because of the clutches. Toyota’s system is still better (for efficiency) because of the losses involved with the clutches.  

    What efficiency losses with clutches?.. these are friction clutches.. once they close they are locked and 100% efficient. I would worry more about wear but these will have a much lighter duty than the ones used in conventional automatic transmissions..


  27. 27
    Alexander

     

    Vote -1 Vote +1

    Alexander
     Says

     

    Sep 27th, 2010 (8:52 am)

    What does the clutch C1 do? Is it a parking brake or so?


  28. 28
    CorvetteGuy

    +2

     

    Vote -1 Vote +1

    CorvetteGuy
     Says

     

    Sep 27th, 2010 (8:54 am)

    Pat Joy: This has to be a patent for the two mode hybrid drive for GM cars and trucks, not the Volt!P  

    Hmmmm. I hope you are right. Then the whole question is “moo”. You know. A “cow’s opinion”. It doesn’t really matter. ;)


  29. 29
    Mike-o-Matic

    +1

     

    Vote -1 Vote +1

    Mike-o-Matic
     Says

     

    Sep 27th, 2010 (8:54 am)

    Rob: Sighted this morning on eastbound I-94 outside Ann Arbor: a car hauler loaded with Chevy Volts! They all sported the white plastic protective film you see nowadays on vehicles en route to dealerships . . .  

    Rob, that must have been pretty mind-blowing. Especially this early!

    Naturally, since we’re not even at “Job One” yet, they couldn’t have been headed for dealerships. Where do you think they *were* going?


  30. 30
    Loboc

    +1

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (8:55 am)

    If this is the Volt final configuration, it suggests that the ICE could be used to drive the wheels by merely changing the computer logic for the clutches. In that mode, however, the generator section would be spinning. Although, energizing the generator to actually produce power could be switched electronically. Interesting.

    I am thinking this is how the Karma is configured. The ICE and Electric Drive motor could be adding their power together for high output bursts. (Volt SS maybe?)

    Makes me wonder why Volt is limited to 104mph. If M/G-A and M/G-B are driving at the same time (Sport mode?), the final drive ratio could be adjusted so that 5,000 rpm for both would equal 10,000 rpm for a single motor. Keeping the motors closer to their torque band.

    This machine is going to be the ultimate tuner car.

    /Major detailed and hard-to-follow discussion of this and other possible M/G-A and M/G-B configuration is over in the engineering forum.


  31. 31
    Chris C.

    +3

     

    Vote -1 Vote +1

    Chris C.
     Says

     

    Sep 27th, 2010 (8:57 am)

    Robert: But whats the second engine for? I cant figure how that would improve things, adding a second engine and third motor, just seems like more weight.

    This is why it’s so tedious to plow through these comments looking for actual interesting info: many of the comments are from people who don’t even read the article before piping up with their trenchant commentary, and don’t think more than 15 seconds before inserting their insightful bon mot.

    FYI, I think carcus3′s comment further above (#8) is actually interesting but it looks like he’s being voted into oblivion.

    Thank you Rick for a great write up. I’m glad you mentioned the patent issue. I think THAT is what frames nearly everything we talk about here. We would love for systems to get designed and built according to technical requirements only, but the reality of the world is that there are patents and lawyers ‘n stuff and sometime you CAN’T build the system you want, because you don’t own the IP, and the owner won’t license it to you!

    I believe this is fundamentally why GM decided to not bother with a Prius-style hybrid and leapfrogged right over them to go straight to the EREV design. Now *GM* will have locked up the IP!


  32. 32
    Loboc

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (9:03 am)

    Flaninacupboard: Toyota’s system is still better (for efficiency) because of the losses involved with the clutches.

    Clutches don’t result in any appreciable losses. They just shift power on/off of the shaft. If you spin the shafts into synchronization before engaging, there would be no detectable loss at all.


  33. 33
    Flaninacupboard

    +2

     

    Vote -1 Vote +1

    Flaninacupboard
     Says

     

    Sep 27th, 2010 (9:06 am)

    CorvetteGuy: If C2 and C3 were to engage together, first of all you could ‘feel it’, and we have seen video of it coming online and it was ‘imperceptible’.   (Quote)

    In the Prius MG1 can go from -6500RPM and ICE at 0RPM, to MG1 at 0RPM and ICE at 1800RPM in less than a second and it could be described as “imperceptible”. i.e. you feel it less than a gear change, but you DO feel it. Volt will be the same, once you’ve been driving it a while you’ll feel the ICE cycling.

    I’m as certain as I can be that the Volt will operate in parallel mode at least some of the time (sometimes series is better, when drive power output is less than 5kw for instance) and i am half disappointed because it’s not the car i thought, but part excited, because it would be possible to rival prius highway mileage which means it’s worth me thinking about buying again!


  34. 34
    Flaninacupboard

    -1

     

    Vote -1 Vote +1

    Flaninacupboard
     Says

     

    Sep 27th, 2010 (9:10 am)

    Loboc: Clutches don’t result in any appreciable losses. They just shift power on/off of the shaft. If you spin the shafts into synchronization before engaging, there would be no detectable loss at all.  (Quote)

    I didn’t decide whether the loss was appreciable or not, simply that it exists. two clutches feeding a plnetary gearset can’t be as efficienct as 0 clutches feeding a planetary gear set. If they had some benefit to utility or economy Toyota would have put them in. they don’t, so they didn’t.


  35. 35
    herm

    +3

     

    Vote -1 Vote +1

    herm
     Says

     

    Sep 27th, 2010 (9:19 am)

    CorvetteGuy: So, from a standing start, both electric motors are engaged to the wheels, but when the ICE comes online, one of them is disengaged and starts to generate electricity. So, in stop and go traffic, it would toggle back and forth based on how much power is needed to the wheels. Is that about right?  

    You got it!.. the generator motor is not really driving the wheels but is does change the gear ratio of the EVT gears. Once it goes into CS mode then the whole thing reverts to a fixed gear ratio.. if you step on the brakes the generator disengages (ICE shuts off) and you get an EVT again to extract the most energy possible from braking. In other words, the generator is not running when the Volt is braking.

    This also means the Volt is more efficient in CD mode than in CS mode, Alex made a mention of that.


  36. 36
    DonC

    +1

     

    Vote -1 Vote +1

    DonC
     Says

     

    Sep 27th, 2010 (9:19 am)

    We know that there is an EVT from a number of sources, so the question is not whether there is such a transmission but how it works. Should be very interesting to find out. I’m sure the engineers want to explain this.

    herm: We recently learned of the 80% brake regen efficiency

    You’re kidding me. 80%? That’s amazing. Where did you learn about that?

    Flaninacupboard: I’m as certain as I can be that the Volt will operate in parallel mode at least some of the time

    I can see where you’d think this but they’ve sworn of the proverbial stack of bibles that it doesn’t.


  37. 37
    RB

    +1

     

    Vote -1 Vote +1

    RB
     Says

     

    Sep 27th, 2010 (9:21 am)

    Great post; thank you.
    It’s an elegant and versatile (though complicated) transmission.
    It could be that the cost of the complexity adds a bit to the manufacturing cost.


  38. 38
    Loboc

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (9:24 am)

    kdawg: So M/G B is always connected to the planetary gearset.Even in nuetral.  

    Since there is no ‘idle’ in an electric motor (you can go to zero rpm and still be ‘on’) this makes sense.


  39. 39
    Loboc

    +1

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (9:40 am)

    Flaninacupboard:
    I didn’t decide whether the loss was appreciable or not, simply that it exists. two clutches feeding a plnetary gearset can’t be as efficienct as 0 clutches feeding a planetary gear set. If they had some benefit to utility or economy Toyota would have put them in. they don’t, so they didn’t.  

    HSD is a different design in that there is no generator involved. If you have three devices and only two input shafts, some method of switching/clutching is needed.

    As far as appreciable losses. If the loss is not measurable or is a decimal point out on the edge of measurable, then, it is functionally the same as zero.

    Maybe Toyota should use a clutch to minimize that harshness of starting the engine while connected to the shaft.


  40. 40
    john1701a

    -15

     

    Vote -1 Vote +1

    john1701a
     Says

     

    Sep 27th, 2010 (9:51 am)

    (click to show comment)


  41. 41
    herm

    +3

     

    Vote -1 Vote +1

    herm
     Says

     

    Sep 27th, 2010 (9:55 am)

    carcus3: #8

    Maybe this is why GM hasn’t released the mpg — they’re still waiting on the lawyers to tell them whether the Volt will be configured as a series hybrid or a series/parallel hybrid.
    /sure sounds a lot like HSD to me  

    To some degree it sounds like HSD, but so does Ford’s system and they have their own patents.. the original design was by a TRW engineer in the late ’60s I believe… and the serial idea belongs to GM since the ’20s

    What this describes is a very versatile system.. it can be configured to be similar to the Ford and Toyota system with the single gearset ( 1 Mode?), or put back in the 2nd gear set and you have a 2 Mode suitable for towing or high speed sports mode, or just a serial configuration with a different software upload.

    GM even designed it so that you can easily use different size motors, longer motors just require a different backcover for the transmission.

    Maybe GM knew what it was doing when they designed the FWD 2 Mode powertrain unit.

    Its going to be scary once hackers get hold of this.


  42. 42
    Loboc

    +6

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (9:57 am)

    john1701a: the delay is a clear indication of a goal not being met yet

    The ‘goal’ is waiting on the EPA to provide a methodology. GM has not delayed anything.


  43. 43
    Loboc

    +1

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (10:00 am)

    herm: Its going to be scary once hackers get hold of this.

    We’re not hackers, we’re ‘tuners’. :) Although, technically, altering software (chipping a car) is ‘hacking’.


  44. 44
    herm

     

    Vote -1 Vote +1

    herm
     Says

     

    Sep 27th, 2010 (10:02 am)

    DonC: herm: We recently learned of the 80% brake regen efficiency

    You’re kidding me. 80%? That’s amazing. Where did you learn about that?

    In the engineering forum, posted by a GM service manager from their training.. I actually prefer the part about the once every 2 years oil change interval. A prudent driver should not use the brakes too often, is just wasting energy.


  45. 45
    Dave K.

     

    Vote -1 Vote +1

    Dave K.
     Says

     

    Sep 27th, 2010 (10:07 am)

    Rob: …a car hauler loaded with Chevy Volts!

    What colors were they? See any unusual panels or mirrors on the cars? NY plates? (hee hee)

    =D-Volt


  46. 46
    herm

    +1

     

    Vote -1 Vote +1

    herm
     Says

     

    Sep 27th, 2010 (10:07 am)

    herm: What this describes is a very versatile system.. it can be configured to be similar to the Ford and Toyota system with the single gearset ( 1 Mode?), or put back in the 2nd gear set and you have a 2 Mode suitable for towing or high speed sports mode, or just a serial configuration with a different software upload.

    If this is true then GM’s statement regarding the Voltec Cadillac Converj (?) is poppycock, this Voltec powertrain can be used pretty much for anything with the right batteries.


  47. 47
    Loboc

    +1

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (10:20 am)

    ziv: What I can’t figure out is what a stationary member is..

    “… while M/G B is driving the wheels through the fixed gear ratio when the Ring gear is held stationary. ”

    They are locking the ring gear through C1 to the case. That way it doesn’t just spin while C2 is disengaged. This effectively makes it a single-fixed-gear ratio from M/G-B through to the final drive (17). If both C2 and C1 are disengaged, it would be in neutral. (Modes 4 or 5.)


  48. 48
    kdawg

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Sep 27th, 2010 (10:26 am)

    Loboc: Since there is no ‘idle’ in an electric motor (you can go to zero rpm and still be ‘on’) this makes sense.

    I was just thinking if you had a problem w/the motor (locked rotor/whatever) and you needed to get towed, the motor would still be spinning (or trying to).


  49. 49
    Van

     

    Vote -1 Vote +1

    Van
     Says

     

    Sep 27th, 2010 (10:27 am)

    I am pretty slow so I cannot discern much of a difference between this and Toyota’s HSD. Instead of MGA and MGB we have MG1 and MG2. Same sun, planet, ring gear configuration. It looks like the idea is to drop in some clutches and claim it does not infringe on existing patent rights. Hope it works, this system is too good to be kept from the competition.


  50. 50
    kgurnsey

    +1

     

    Vote -1 Vote +1

    kgurnsey
     Says

     

    Sep 27th, 2010 (10:33 am)

    My question is: How long will it take the “tuners” to unlock the rest of the battery? If Mitsubishi can make an EV with a 16 kWh battery, I wouldn’t be too worried about unlocking an extra 20-30% of the Volt’s heavily pampered battery pack for some extra EV range.

    As for the transmission, I’ve thought all along that in the end, the Prius, the Volt, and Ford’s plug-in systems will all be splitting hairs from each other. I guessed a while back that the Volt is using a variation of the two mode transmission. It just makes sense technically. They are all hybrids, really, by definition anyway. The biggest difference between the Volt and the Prius is that the Volt has a bigger drive motor, to give EV only drive at a higher speed and rate of acceleration, and a bigger battery for more range. Not to knock those differences, mind you, they are game changing. Technically though there is very little keeping the Prius from operating like a Volt. There is a company that hacks Priuses that has already developed a system to give the Gen 3 Prius capabilities that are very, very similar to the Volt.

    http://green.autoblog.com/2010/07/26/piccs-latest-converted-plug-in-prius-boasts-40-mile-electric-ra/

    It does 70+ mph in EV only mode, and can do about 40 miles on electrons only. Sound familiar?

    As an aside, even if GM never chooses to use the connection between the engine and the final drive, the clutches to make it possible would be needed to allow the generator to drive the sun gear for the EVT anyway. Thus it’s a moot point. GM might as well drive the wheels with the engine when it’s most efficient, since the clutches are already there.

    The point is, electric only drive for as long a range as possible, at all speeds, with a generator to back you up. Who cares how the get ‘er done?


  51. 51
    iroc

     

    Vote -1 Vote +1

    iroc
     Says

     

    Sep 27th, 2010 (10:46 am)

    Isn’t this what GM uses in the Sierra/Tahoe 2-MODE HYBRIDS ?


  52. 52
    Flaninacupboard

    +1

     

    Vote -1 Vote +1

    Flaninacupboard
     Says

     

    Sep 27th, 2010 (10:46 am)

    Loboc: HSD is a different design in that there is no generator involved. If you have three devices and only two input shafts, some method of switching/clutching is needed.As far as appreciable losses. If the loss is not measurable or is a decimal point out on the edge of measurable, then, it is functionally the same as zero.Maybe Toyota should use a clutch to minimize that harshness of starting the engine while connected to the shaft.  (Quote)

    Prius does have a generator, in fact it has two MG’s, MG1 (small) and MG2 (big). In H mode (Heretical, because no-one though it ran this way) MG1 drives the car, using power scavenged by MG2, which is being turned by the ICE.

    No clutch is neccesary, and it’s definitely not harsh when the ICE starts.


  53. 53
    Flaninacupboard

    +1

     

    Vote -1 Vote +1

    Flaninacupboard
     Says

     

    Sep 27th, 2010 (10:48 am)

    kdawg: I was just thinking if you had a problem w/the motor (locked rotor/whatever) and you needed to get towed, the motor would still be spinning (or trying to).  (Quote)

    Yep, just like Prius.


  54. 54
    CorvetteGuy

     

    Vote -1 Vote +1

    CorvetteGuy
     Says

     

    Sep 27th, 2010 (10:54 am)

    Flaninacupboard: i.e. you feel it less than a gear change, but you DO feel it. Volt will be the same, once you’ve been driving it a while you’ll feel the ICE cycling.

    When I say you would ‘feel it’, I mean the same as you would feel a gear change in a regular car, or more specifically, just like the V8 in the 2-Mode Hybrid Tahoe coming online. That .25 second change in vehicle speed as the torque of the engine balances with vehicle speed.

    I’m sure in the Volt, because it is so quiet on the inside, that when the CS Mode starts and you are paying attention, you might feel a slight ‘shudder’ in the steering wheel. But if this C2 clutch is not engaged, that power coming online would not be felt throughout the drive train. IMO.


  55. 55
    pjkPA

    -2

     

    Vote -1 Vote +1

    pjkPA
     Says

     

    Sep 27th, 2010 (10:56 am)

    Looks like too much info to be posted… not sure if that’s a good thing.
    I’m sure this kind of dicussion is saving competitors some time and effort.
    We make it too easy for them.. then we wonder why our companies who can’t even sell cars in major competitor’s markets.. have come on hard times and millions of Americans lose their jobs.


  56. 56
    Larry McFall

    -4

     

    Vote -1 Vote +1

    Larry McFall
     Says

     

    Sep 27th, 2010 (11:01 am)

    What in the hell is this “Transmission” stuff. Are they referring to an electrical transmission of power to the electrical drive (i.e., traction motor) motor????

    My understanding was that the VOLTEC employed a none mechanical drive linkage to the drive wheels and if this is so, what is this that now seems to be another hot issue with the VOLT? Does it ever stop or are we to a point that every little stupid issue that comes becomes a major disaster.

    The Volt should be ready to hit the road and actually make some appearance in public. What does a patent have anything to do with anything at this late of date. If the “New GM” can’t take care of business in a timely manner can we really aspect the Volt to be available anytime soon.

    It sounds much like the shades of the past with GM. Being an old GM family member I have seen GM conduct themselves a lot better in the past and took much pleasure in what they developed without a lot of issues coming up that they didn’t work out quickly. So these young GM executives need to work it out and quit talking so much and just get the job done.


  57. 57
    Texas

    +1

     

    Vote -1 Vote +1

    Texas
     Says

     

    Sep 27th, 2010 (11:07 am)

    Ah! A Toyota-like hybrid. This is the best way to get good efficiency at highway speeds and also to be able to utilize all three motors (ICE, gen, main drive motor) for extra power. You also get the benefit of having more total horsepower.

    This is what I thought they should do, and said as such in dozens of past posts, but didn’t think they were actually going to do it, unless they had trouble getting good numbers with a pure serial drivetrain.

    Only a few months to go before we know the truth. Is it just a Toyota plug-in or a true pure series hybrid with no mechanical link? I’m hoping for the mechanical link because it will mean better performance but I’m guessing many people will be upset with this reality based on physics.

    The main disadvantages to this setup are increased complexity and cost. It prevents easy swapping of the genset because it will need to be carefully matched to the rest of the drivetrain and software.

    If this is true, I guess we can agree that our society continues to get more complex. Soon, no one person can understand all of the technologies in any one device. Too bad. The days of one man in his basement inventing things (other than software) seem to have already passed. Imagine how exciting it was to invent the airplane, phonograph, movie camera, etc…


  58. 58
    tom w

    +6

     

    Vote -1 Vote +1

    tom w
     Says

     

    Sep 27th, 2010 (11:12 am)

    Randy: Not exactly on subject but just read another Peak OIL article and this one is really scary ,

    Randy;
    Don’t think Peak Oil is ever off Topic, though that article isn’t a new one. The importance of reducing our use of oil drastically is the driving force behind the Volt. And I can’t wait to get one (though I may get a leaf if it become available in Ohio first, I’m on waiting list for Leaf as well as at local Chevy dealer for Volt).

    Of course Peak Oil is just one reason, but its certainly under the category of saving our standard of living (keeping Oil money in our economy etc.).

    Actually, I believe if managed correctly, Peak Oil could save our economy. If we can manage for example a yearly minimum 10% drop in yearly Oil Usage, this will keep Oil prices from raising too much as we can try and match the drop in supply with an equal drop in demand.

    This will create new industries (not just electric cars and batteries, but building out the GRID, home wind and solar energie, replacing fuel oil furnaces etc.).


  59. 59
    Mike D.

    +1

     

    Vote -1 Vote +1

    Mike D.
     Says

     

    Sep 27th, 2010 (11:19 am)

    pjkPA: Looks like too much info to be posted… not sure if that’s a good thing.
    I’m sure this kind of dicussion is saving competitors some time and effort.
    We make it too easy for them.. then we wonder why our companies who can’t even sell cars in major competitor’s markets..have come on hard times and millions of Americans lose their jobs.  

    That’s why it is a patent. Every car company knows how every other car companies stuff works, if not before, then right after they go on sale. The patent ensures that if anyone uses this setup, GM can sue them into oblivion.


  60. 60
    CorvetteGuy

    +3

     

    Vote -1 Vote +1

    CorvetteGuy
     Says

     

    Sep 27th, 2010 (11:35 am)

    Texas: Ah! A Toyota-like hybrid. This is the best way to get good efficiency at highway speeds and also to be able to utilize all three motors (ICE, gen, main drive motor) for extra power. You also get the benefit of having more total horsepower.

    Does this mean it took American know-how to make a Japanese idea better? ;)


  61. 61
    nasaman

    +7

     

    Vote -1 Vote +1

    nasaman
     Says

     

    Sep 27th, 2010 (11:36 am)

    Larry McFall, #55: What in the hell is this “Transmission” stuff. Are they referring to an electrical transmission of power to the electrical drive (i.e., traction motor) motor????

    My understanding was that the VOLTEC employed a none mechanical drive linkage to the drive wheels and if this is so, what is this that now seems to be another hot issue with the VOLT? Does it ever stop or are we to a point that every little stupid issue that comes becomes a major disaster…

    Great topic & a very well written description/explanation, Rick! And you’re right that much of what we know about it is really speculation at this time.

    Larry, I understand the word “transmission” as applied to Voltec to mean an EVT (electronically variable transmission) which, similar to a CVT (its mechanical distant cousin), does not shift abruptly between gear ratios like conventional manual or automatic transmissions. So if the motor control electronics “feather” all mode changes by controlling waveform rise and fall times (not hard to do), any gear ratio changes can be made virtually imperceptible. From the patent drawing above it’s also clear that the “engine” is connected electrically, NEVER mechanically, to the drive wheels.

    Therefore, if this patent actually applies to Voltec, we can conclude at least:

    1) that this “transmission” does NOT “shift” abruptly in the usual sense, and

    2) that the ICE is ONLY connected to a M/G, NEVER directly to the wheels.

    Also note that all new Volt purchasers are told in writing by GM that the Volt’s transmission is an “ELECTRONIC RATIO SELECT, STRONG HYBRID, EVT“. Or, as Bob Lutz would probably still say, a “transmission unlike any other”. Again, an excellent presentation, Rick!


  62. 62
    CorvetteGuy

     

    Vote -1 Vote +1

    CorvetteGuy
     Says

     

    Sep 27th, 2010 (11:48 am)

    One more thing, then back to work: Since the goal of the Volt is maximum use of the battery and not the ICE Gen, the fact that “in theory” both C2 and C3 clutches “could engage” at the same time really changes nothing. It’s not going to happen because there is no need for it. That design seems to eliminate a third Generator Motor by allowing Motor 2 to switch back and forth between Drive Motor and Generator while at the same time having the ICE ready to go online as needed.

    Nothing has changed! Nothing to see here people! Move along… Move along… !


  63. 63
    Cab Driver

    +1

     

    Vote -1 Vote +1

    Cab Driver
     Says

     

    Sep 27th, 2010 (11:52 am)

    Flaninacupboard: As soon as they said “two motors” some time ago it was obvious it would be a CVT in there. I am going to call it that the engine IS engaged to the wheels. why am i so sure?In CD mode MG1&2 work in tandem (via C2) as a CVT to get the best efficiency from the two motors. It’ll feel like the prius.In CS mode if C2 is -not- engaged you’ll be in mode one with a single speed transmission. Suddenly your response is completely different, and it would not be a great drive. You have to engage C2 to allow the CVT to work, and then you’re in power split. In one way this is good news, CS MPG would be a ton better with power split. in another it’s bad, it’s not what i thought the Volt was…I don’t -think- this infringes toyota’s IP because of the cluthces. Toyota’s system is still better (for efficiency) because of the losses involved with the clutches.  (Quote)

    Flan,

    Good comment. When I first considered the configuration in the patent app I had the reservation that it seemed like the performance in CS mode would be compromised relative to CD mode. GM has repeatedly said that Volt performance is the same in CD and CS.

    Since then I re-read the Alex Cattelan interview and realized that the dominant factor in performance is the 110 kW power limit of the power inverter and battery. Even though the sum of the power ratings for M/G A plus M/G B is greater than 110 kW, the Volt only uses 110 kW total.

    It is true that Mode 1: Electric Motor-only doesn’t have the flexible gear ratio that Mode 6: 2 Electric Motor-only does; but I believe the use of Mode 6 has been tuned to get the best possible efficiency in CD mode, not extra performance versus Mode 1.


  64. 64
    koz

    +1

     

    Vote -1 Vote +1

    koz
     Says

     

    Sep 27th, 2010 (12:04 pm)

    Could be used on the Volt, but instead it could be for the plug-in two-mode system that was supposed to be in the Vue. Interesting either way, but I’ld love to here more comments from GM on the subject.


  65. 65
    EricLG

    -16

     

    Vote -1 Vote +1

    EricLG
     Says

     

    Sep 27th, 2010 (12:06 pm)

    (click to show comment)


  66. 66
    nasaman

    +2

     

    Vote -1 Vote +1

    nasaman
     Says

     

    Sep 27th, 2010 (12:07 pm)

    Cab Driver, #63: …Since then I re-read the Alex Cattelan interview and realized that the dominant factor in performance is the 110 kW power limit of the power inverter and battery. Even though the sum of the power ratings for M/G A plus M/G B is greater than 110 kW, the Volt only uses 110 kW total…

    I’ve always found it interesting, although it may only be a coincidence, that each of the 2 M/G’s in the Vue’s 2-mode transmission are rated at 55kW …and the Volt’s able to supply up to 110kW.


  67. 67
    Cab Driver

     

    Vote -1 Vote +1

    Cab Driver
     Says

     

    Sep 27th, 2010 (12:14 pm)

    CorvetteGuy: It looks like a lot of chum in the water for the trolls, assuming they can understand all that. It looks to me like there will be a lot of toggling between clutch C2 and C3. We have been told that in CS Mode, that the engine will run at one of several different RPMs based on electricity need at the time, and that is unrelated to vehicle speed. If C2 and C3 were to engage together, first of all you could ‘feel it’, and we have seen video of it coming online and it was ‘imperceptible’. So, from a standing start, both electric motors are engaged to the wheels, but when the ICE comes online, one of them is disengaged and starts to generate electricity. So, in stop and go traffic, it would toggle back and forth based on how much power is needed to the wheels. Is that about right?  (Quote)

    Hi CorvetteGuy,

    You better be nice to me since I live near your dealership and I could become a customer! (Just kidding!)

    As I said in the post GM may have chosen to use only Mode 2: Series in CS mode. If they have chosen to also use Mode 3: Output Split, I am confident that engine starts and stops would happen in Mode 2 rather than in Mode 3 and they would be very smooth.

    Similarly any transitions between modes would be made smooth by careful management of the rotational speeds while engaging clutches.


  68. 68
    EricLG

    -11

     

    Vote -1 Vote +1

    EricLG
     Says

     

    Sep 27th, 2010 (12:15 pm)

    (click to show comment)


  69. 69
    JohnK

     

    Vote -1 Vote +1

    JohnK
     Says

     

    Sep 27th, 2010 (12:16 pm)

    Rob: Sighted this morning on eastbound I-94 outside Ann Arbor

    What would a load of Volts be doing going EAST? The manufacturing plant is on I94 about 30 miles EAST of there? This implies that they had first been carried somewhere WEST of Ann Arbor. Possibly by rail?


  70. 70
    EricLG

    -24

     

    Vote -1 Vote +1

    EricLG
     Says

     

    Sep 27th, 2010 (12:19 pm)

    (click to show comment)


  71. 71
    stas peterson

    +3

     

    Vote -1 Vote +1

    stas peterson
     Says

     

    Sep 27th, 2010 (12:24 pm)

    Lyle,

    I’m sorry but as an engineer this sounds more like the setup in the GM dual mode hybrid transmission used in the Trucks and in the aborted Buick RendezVUE. It does NOT sound like the drive-train setup in a VOLT.

    Sounds like the wrong Patent is being referenced, to me.


  72. 72
    john1701a

    -19

     

    Vote -1 Vote +1

    john1701a
     Says

     

    Sep 27th, 2010 (12:24 pm)

    (click to show comment)


  73. 73
    JeremyK

    +2

     

    Vote -1 Vote +1

    JeremyK
     Says

     

    Sep 27th, 2010 (12:25 pm)

    A lot of people like to quote Watt-hr/mile numbers from the Tesla on the EPA cycle. I think the Volt will be significantly better due to the EVT setup. Also consider that regen braking can be optimized, just as acceleration and cruising with be with EVT.

    I recently rode in one of GM’s fuel cell powered Equinox. It was able to dump about 30kW of regen back to the batteries during heavy braking, which is about 20% of the output. Note that this was limited by the software for drivability reasons, not the battery or mechanical systems.

    80% regen sounds feasible, since the discharge and charge power output to/from a battery is pretty much the same. The much larger battery in the Volt will be able to accept all kinds of regen power. In theory, the Volt should be able to decelerate at about the same rate as it accelerates using only regen. braking. As an aggressive driver, I can’t wait to drive this thing is in “L” in the city and recoup all those heat losses that I would normally incur.


  74. 74
    Cab Driver

    +1

     

    Vote -1 Vote +1

    Cab Driver
     Says

     

    Sep 27th, 2010 (12:37 pm)

    stas peterson: Lyle,I’m sorry but as an engineer this sounds more like the setup in the GM dual mode hybrid transmission used in the Trucks and in the aborted Buick RendezVUE. It does NOT sound like the drive-train setup in a VOLT.Sounds like the wrong Patent is being referenced, to me.  (Quote)

    Stas,
    I can’t prove that this patent app describes the Volt transmission, but I am sure that it doesn’t describe the 2 Mode hybrid transmission. This patent app has 1 planetary gearset which allows 1 EVT range (Output Split). The 2 Mode hybrids are called 2 Mode because they have 2 EVT ranges (Output Split and Compound Split). The second EVT range requires two planetary gearset in the FWD 2 Mode hybrid and three planetary gearset in the RWD 2 Mode hybrid. The 2 Mode hybrid is a relative of the transmission in this patent app, but is significantly more complex.

    You say “It does NOT sound like the drive-train setup in a VOLT.” Could you be more specific?


  75. 75
    DonC

    +1

     

    Vote -1 Vote +1

    DonC
     Says

     

    Sep 27th, 2010 (12:46 pm)

    nasaman: I’ve always found it interesting, although it may only be a coincidence, that each of the 2 M/G’s in the Vue’s 2-mode transmission are rated at 55kW …and the Volt’s able to supply up to 110kW.  

    They’ve said that one MG is much larger than the other and that it’s not 2 55kW MGs. IOW it’s not a two-mode setup.


  76. 76
    CorvetteGuy

     

    Vote -1 Vote +1

    CorvetteGuy
     Says

     

    Sep 27th, 2010 (12:51 pm)

    Cab Driver: Hi CorvetteGuy,
    You better be nice to me since I live near your dealership and I could become a customer! (Just kidding!)

    I just got off the phone with one of my early Volt Customers who said that our fair city has approved a $2,500 Incentive (not sure yet if it’s a rebate or tax thing) only IF you purchase your New Chevrolet Volt from a dealer in our city, which would be me.

    He says he was in the City Council meeting when this was decided, and he is getting me the contact info so I can get more specifics. My point is, if this is true, ALL OF YOU GUYS should contact your local City Council to see if they have any plans to implement a “Green Policy” that would include incentives to buy in your home city.

    Good luck! We’re all counting on you!


  77. 77
    Loboc

    +9

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (12:56 pm)

    john1701a:
    There’s nothing stopping GM from sighting real-world driving results.In fact, it’s common for pre-rollout test-drives to sight efficiency observations.  

    When you have a vehicle that can get anywhere between 50mpg and infinity, showing preliminary test results would be premature and confusing.

    Given the 230mpg backlash, I’m thinking that waiting for EPA is prudent.


  78. 78
    kForceZero

     

    Vote -1 Vote +1

    kForceZero
     Says

     

    Sep 27th, 2010 (12:58 pm)

    EricLG:
    You remind me of a couple years ago when hordes of Voltards would dance and scream “no transmission, no transmission, nah nah,” followed by “and only $25k!!!!” and “40 AER!!!!!” and “50 CS mpg!!!!!!!!!!!!!!!”

    It’s amazing how it all came to be true isn’t it? Well, not the $25K part – you made that up, nobody ever said that. The MSRP was also widely expected to be what it actually turned out to be.

    As for the “no transmission” comment – of course a car has to have *some* transmission, how else is it going to go anywhere? Though many may have used the phrase “no transmission” as a matter of speaking, they of course meant no conventional multi-gear (automatic/manual) transmission. If anybody thought that a car could drive with no transmission whatsoever then some grade-5 science program would be in order for them.


  79. 79
    Cab Driver

     

    Vote -1 Vote +1

    Cab Driver
     Says

     

    Sep 27th, 2010 (1:00 pm)

    Alexander: What does the clutch C1 do? Is it a parking brake or so?  (Quote)

    Clutch C1 stops the Ring gear from rotating when it is engaged and C2 is disengaged. This causes any power from M/G B to be sent to the Final Drive with a fixed gear ratio when in Mode 1: 1 Motor Electic-only or Mode 2: Series.


  80. 80
    Timaaayyy!!!

     

    Vote -1 Vote +1

    Timaaayyy!!!
     Says

     

    Sep 27th, 2010 (1:24 pm)

    Can I get it in dark blue?


  81. 81
    Flaninacupboard

    +2

     

    Vote -1 Vote +1

    Flaninacupboard
     Says

     

    Sep 27th, 2010 (1:35 pm)

    Ok, just nailed it. If MGB is less than 110kw then 100% it is power split. Why? In CS mode with C2 disengaged ONLY the power from MGB can get to the output shaft. Somehow i don’t think they’ll let it have less power in CS than CD mode! The technical forums seem to think there’s a 55kw and an 80kw or so motor used. That means to get full power either C2 is engaged and C3 is disengaged (meaning the ICE stops and you’re back in EV mode) or C2 is engaged, allowing torque transfer from the ICE and MGA to the output shaft.

    Thoughts?


  82. 82
    BillR

    +1

     

    Vote -1 Vote +1

    BillR
     Says

     

    Sep 27th, 2010 (1:39 pm)

    stas peterson: Lyle,I’m sorry but as an engineer this sounds more like the setup in the GM dual mode hybrid transmission used in the Trucks and in the aborted Buick RendezVUE.It does NOT sound like the drive-train setup in a VOLT.Sounds like the wrong Patent is being referenced, to me.  

    I believe this may be the patent application for the 2-mode Vue with its 4 fixed gear ratios.

    http://www.wipo.int/pctdb/en/wo.jsp?wo=2006107577

    Cab Driver seems to have found the best example of a possible Volt transmission that we have seen.


  83. 83
    Mike-o-Matic

    +2

     

    Vote -1 Vote +1

    Mike-o-Matic
     Says

     

    Sep 27th, 2010 (1:41 pm)

    Timaaayyy!!!: Can I get it in dark blue?  

    Your “transmission?” :D
    That’s an unusual request!


  84. 84
    Timaaayyy!!!

    +1

     

    Vote -1 Vote +1

    Timaaayyy!!!
     Says

     

    Sep 27th, 2010 (2:02 pm)

    Ok, my response to Mike-O-M just went into cyberspace limbo.

    Can I get a baptism? Or is it bapshizzle?


  85. 85
    carcus3

    -1

     

    Vote -1 Vote +1

    carcus3
     Says

     

    Sep 27th, 2010 (2:04 pm)

    Flaninacupboard: Thoughts? 

    If you assume that the Volt was a pure series hybrid, you could make some guestimations about design, performance and resulting efficiency.

    But if GM is actually using this “clutched HSD” (or perhaps, HSD+) in the Volt, then the combinations are limited only by the software controlling it — and this might allow for the use of Atkinson valve timing in the ICE.

    This “patent reveal” has vastly complicated “scratch-sheet speculation” on Volt’s design/performance as far as I’m concerned.

    /BTW, nice job Cab Driver, sniffing this one out.


  86. 86
    Loboc

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (2:05 pm)

    stas peterson: Lyle,I’m sorry but as an engineer this sounds more like the setup in the GM dual mode hybrid transmission used in the Trucks and in the aborted Buick RendezVUE.It does NOT sound like the drive-train setup in a VOLT.Sounds like the wrong Patent is being referenced, to me.  

    A patent doesn’t necessarily have to refer to an exact implementation. They are usually pretty general so that a small change wouldn’t invalidate your patent. Parts of this patent and others could refer to multiple different iterations of the same idea in very different implementations. You don’t even have to demonstrate a working model to get a patent on an idea.

    Let’s say you patent a new and so far unknown way to build an ultra capacitor. That idea could be used and protected from infringement in any engineered product from an electric toothbrush to an electric airplane.

    /I am definitely not a patent attorney, so, hire one if needed. See ‘Flash of Genius’ for 90% of my knowledge in this area.


  87. 87
    unni

    -3

     

    Vote -1 Vote +1

    unni
     Says

     

    Sep 27th, 2010 (2:30 pm)

    BillR:
    I believe this may be the patent application for the 2-mode Vue with its 4 fixed gear ratios.http://www.wipo.int/pctdb/en/wo.jsp?wo=2006107577Cab Driver seems to have found the best example of a possible Volt transmission that we have seen.  

    I too think in same lines. This looks to me more for the 2 mode plugin gearbox than volt’s.
    I wonder volt is becoming a 2 mode plugin hybrid with 40 miles ev range as component sharing will make things cheaper and GM knows its blunder to set a full production setup for a limited production machine is never going to pay off.


  88. 88
    Loboc

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (2:31 pm)

    I finally got around to going to the link provided in the article:

    “If you want help understanding how a planetary gearset works here is a link to help:”

    http://auto.howstuffworks.com/automatic-transmission2.htm

    Very cool stuff. The old mechanical hydro-brains have been replaced by computers today. This makes it easier to have paddle shifters and auto-stick since it’s a wire instead of a hydro-switch.


  89. 89
    Dave K.

    +2

     

    Vote -1 Vote +1

    Dave K.
     Says

     

    Sep 27th, 2010 (2:35 pm)

    Flaninacupboard: …torque transfer from the ICE and MGA to the output shaft.

    Thoughts?

    Going on driver feedback. One demo driver said the Volt seemed to have a little more power in CS. Went on to say it may be because of the slight revving which can be heard. GM engineers are saying, “Seamless transition”.

    =D-Volt

    Volt%20garage1.jpg


  90. 90
    EricLG

    -21

     

    Vote -1 Vote +1

    EricLG
     Says

     

    Sep 27th, 2010 (3:01 pm)

    (click to show comment)


  91. 91
    Dan Petit

    +6

     

    Vote -1 Vote +1

    Dan Petit
     Says

     

    Sep 27th, 2010 (3:10 pm)

    When I drove the Volt last March 13th, it was the smoothest forward motion I’d ever experienced in my life. It was the quietest as well. Transmission of the electric power to the road was the most refined sensation that one could imagine. I likened it to a very positive dream where you are flying through the air at will.
    While we had discussed in the distant past that the Volt will not have a conventional transmission as we (especially techs) knew it, it will be really interesting when GM feels comfortable in letting many of us actually see a graphic of it.
    (I know of several great techs at a local (very honest) transmission shop in the far North East Austin area who will really enjoy a graphic of the Volt transmission including the motor/generator assemblies).

    Driving the Volt proved to me that this new technology is so extremely far ahead (sensation-wise) from anything else on the planet, that there will not be anyone who considers themselves an “auto buff” who will not immediately come to respect the Volt and GM very deeply, once they get a chance to test drive it. (Including their competitors.)

    /…back to work. Have a great day everyone!)


  92. 92
    BLIND GUY

     

    Vote -1 Vote +1

    BLIND GUY
     Says

     

    Sep 27th, 2010 (3:25 pm)

    Could this design be the result of the joint venture GM has with Bright Automotive? I wouldn’t mind having a small plastic model of this trans, like the old clear plastic models of V8s. OT I heard a short Blurb on TV saying that the inventor of the Segway has died after going off a cliff somewhere across the pond. If so, it’s a great lose. He invented numerous products that have benefited mankind.


  93. 93
    Cab Driver

     

    Vote -1 Vote +1

    Cab Driver
     Says

     

    Sep 27th, 2010 (3:28 pm)

    Flaninacupboard: Ok, just nailed it. If MGB is less than 110kw then 100% it is power split. Why? In CS mode with C2 disengaged ONLY the power from MGB can get to the output shaft. Somehow i don’t think they’ll let it have less power in CS than CD mode! The technical forums seem to think there’s a 55kw and an 80kw or so motor used. That means to get full power either C2 is engaged and C3 is disengaged (meaning the ICE stops and you’re back in EV mode) or C2 is engaged, allowing torque transfer from the ICE and MGA to the output shaft.Thoughts?  (Quote)

    Your observation is valid. My belief is that M/G B is 110 kW. That way full performance is available in Mode 1: 1 Motor Electric-only and Mode 2: Series.

    This doesn’t mean GM does or doesn’t use Output Split mode. We’ll just have to see.


  94. 94
    Loboc

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (3:35 pm)

    BLIND GUY: Could this design be the result of the joint venture GM has with Bright Automotive?I wouldn’t mind having a small plastic model of this trans, like the old clear plastic models of V8s.OTI heard a short Blurb on TV saying that the inventor of the Segway has died after going off a cliff somewhere across the pond.If so, it’s a great lose.He invented numerous products that have benefited mankind.  

    It was the CEO not the inventor.

    http://abcnews.go.com/Health/Wellness/segway-accident-kills-jimi-heselden-segway-boss/story?id=11736855


  95. 95
    EricLG

    -1

     

    Vote -1 Vote +1

    EricLG
     Says

     

    Sep 27th, 2010 (3:35 pm)

    BLIND GUY: Could this design be the result of the joint venture GM has with Bright Automotive?I wouldn’t mind having a small plastic model of this trans, like the old clear plastic models of V8s.OTI heard a short Blurb on TV saying that the inventor of the Segway has died after going off a cliff somewhere across the pond.If so, it’s a great lose.He invented numerous products that have benefited mankind.  

    Dean Kamens invented the Segway. The fellow who died is a brit who bought the Segway business from Kamens


  96. 96
    Cab Driver

     

    Vote -1 Vote +1

    Cab Driver
     Says

     

    Sep 27th, 2010 (3:41 pm)

    BLIND GUY: Could this design be the result of the joint venture GM has with Bright Automotive? I wouldn’t mind having a small plastic model of this trans, like the old clear plastic models of V8s. OT I heard a short Blurb on TV saying that the inventor of the Segway has died after going off a cliff somewhere across the pond. If so, it’s a great lose. He invented numerous products that have benefited mankind.  (Quote)

    The patent app was filed in September 2007 and the joint venture with Bright is only a few months old, so I don’t see any connection there.


  97. 97
    Cab Driver

     

    Vote -1 Vote +1

    Cab Driver
     Says

     

    Sep 27th, 2010 (3:51 pm)

    Robert: Very nice Post,This really makes me think GM is developing the most advanced cars out there, it could be that the transition to output split mode was just too rough and they decided not to use it, I would think transitioning between these differant modes would be the tricky part.And you dont want to engage all 3 clutches at the same time.But whats the second engine for? I cant figure how that would improve things, adding a second engine and third motor, just seems like more weight.  (Quote)

    You’re right that C1 and C2 should never be engaged at the same time.

    You’re also right that the software to control all this stuff is the tricky part. That’s why GM was so enthused to use the control software for the 2 Mode hybrid as a starting point for developing the Volt control software.

    Finally, as I said in the original post description of Figure 1: “Don’t worry about the second, dashed, copies of Engine and M/G A, they just show an optional alternative configuration without clutch C3.”


  98. 98
    BLIND GUY

     

    Vote -1 Vote +1

    BLIND GUY
     Says

     

    Sep 27th, 2010 (3:53 pm)

    Thanks for the clarification everyone,


  99. 99
    joe

     

    Vote -1 Vote +1

    joe
     Says

     

    Sep 27th, 2010 (3:54 pm)

    nasaman:
    Great topic & a very well written description/explanation, Rick! And you’re right that much of what we know about it is really speculation at this time.Larry, I understand the word “transmission” as applied to Voltec to mean an EVT (electronically variable transmission) which, similar to a CVT (its mechanical distant cousin), does not shift abruptly between gear ratios like conventional manual or automatic transmissions. So if the motor control electronics “feather” all mode changes by controlling waveform rise and fall times (not hard to do), any gear ratio changes can be made virtually imperceptible. From the patent drawing above it’s also clear that the “engine” is connected electrically, NEVER mechanically, to the drive wheels.
    Therefore, if this patent actually applies to Voltec, we can conclude at least:
    1) that this “transmission” does NOT “shift” abruptly in the usual sense, and
    2) that the ICE is ONLY connected to a M/G, NEVER directly to the wheels.
    Also note that all new Volt purchasers are told in writing by GM that the Volt’s transmission is an “ELECTRONIC RATIO SELECT, STRONG HYBRID, EVT“. Or, as Bob Lutz would probably still say, a “transmission unlike any other”. Again, an excellent presentation, Rick!  

    I understand that the Volt is using an AC electric motor, thus allowing an easy way to control the rpm’s by using an AC motor speed control. Years ago, an AC motor speed was controlled by changing the AC voltage. Today AC cycles is used to vary speeds of an electric motor w/o loosing any torque. So controlling the speed hardly needs a transmission.


  100. 100
    Shawn Marshall

     

    Vote -1 Vote +1

    Shawn Marshall
     Says

     

    Sep 27th, 2010 (3:57 pm)

    Whew!


  101. 101
    joe

     

    Vote -1 Vote +1

    joe
     Says

     

    Sep 27th, 2010 (4:10 pm)

    from joe @99

    I wanted to elaborate more @ 99 ,but somehow I must have press the enter, because I found myself working against the clock causing me to lose my train of thoughts.


  102. 102
    CorvetteGuy

    +1

     

    Vote -1 Vote +1

    CorvetteGuy
     Says

     

    Sep 27th, 2010 (5:20 pm)

    CorvetteGuy: I just got off the phone with one of my early Volt Customers who said that our fair city has approved a $2,500 Incentive

    Update: I spoke to a member of the City Council, and it is TRUE, they approved a cash incentive for Individuals (no fleet sales) to get $2,000 if they buy a Hybrid or an Electric Car from a dealer in our city.

    This applies to Nissan Leaf, Chevy Volt, Toyota Prius, GEM, Lexus, Honda, Mercedes, and any other Electric or Hybrid vehicle on the market from a mainstream manufacturer. I think everyone should give a call to their City Councilman and see what your town is doing to promote “Green Vehicles”…!

    How cool is that?!!!!


  103. 103
    UAW_Thugs Must_Die

    -19

     

    Vote -1 Vote +1

    UAW_Thugs Must_Die
     Says

     

    Sep 27th, 2010 (5:20 pm)

    (click to show comment)


  104. 104
    Dave K.

     

    Vote -1 Vote +1

    Dave K.
     Says

     

    Sep 27th, 2010 (6:00 pm)

    Off topic:

    Here’s a photo of the new Caddy next door. This car is a looker. In the background is my red truck. And the garage which will power the 2011 Volt.

    Caddy%20next%20door.jpg

    It is very good news that the Volt is being manufactured on the same line as the Caddilac and Buick. Good job GM. Wait until the world gets a taste of the new Volt.

    =D-Volt


  105. 105
    nasaman

    +3

     

    Vote -1 Vote +1

    nasaman
     Says

     

    Sep 27th, 2010 (6:09 pm)

    Dan Petit, #91: When I drove the Volt last March 13th, it was the smoothest forward motion I’d ever experienced in my life. It was the quietest as well. Transmission of the electric power to the road was the most refined sensation that one could imagine. I likened it to a very positive dream where you are flying through the air at will…

    …Driving the Volt proved to me that this new technology is so extremely far ahead (sensation-wise) from anything else on the planet, that there will not be anyone who considers themselves an “auto buff” who will not immediately come to respect the Volt and GM very deeply, once they get a chance to test drive it. (Including their competitors.)

    /…back to work. Have a great day everyone!)

    Dan, I’d venture that you, as a full-time automotive repair shop instructor, have far more hands-on experience with cars of all makes than almost anyone else here —certainly MUCH more than I do. That’s why I’m always delighted to read your outspoken praise for your Volt test drive, which confirms my own. I’ve driven everything from ‘motorcycles to motorhomes’ in 25 countries all over the world, and I was absolutely BLOWN AWAY by the Volt test drive!!!

    /Like Tag says from his test drive, the Volt was “quiet as a mouse & soft as a butterfly”. I’d add that it has the strength, sureness and agility of a leopard! :) :) :)


  106. 106
    Dave K.

     

    Vote -1 Vote +1

    Dave K.
     Says

     

    Sep 27th, 2010 (6:39 pm)

    Oops, sorry for the spelling error on Cadillac in post 104. Like I tell my wife when she catches me checking out a pretty girl. “My finger may be married, but my eyes are single”.

    =D-Volt

    Caddy%20next%20door%201.jpg


  107. 107
    JCook

     

    Vote -1 Vote +1

    JCook
     Says

     

    Sep 27th, 2010 (7:37 pm)

    If this is truly the Volt’s transmission I can say this. It is a highly flexible system with endless possibilities controlled by software to increase efficiency.

    There has been a lot of argument about the M/G motor sizes. From an engineering perspective there is no reason for M/G B to be the whole 110 kw with this setup. To save weight it would make sense to make it smaller and use both M/G’s at the same time. Think about it this way for most cruising in CS and CD mode 1 is just fine but during takeoff mode2 can be used; and this can be in both CS and CD. Nothing says that even when the ICE is running (CS mode) they can’t momentarily go from mode 2 to mode 6 and then back to mode 2 to continue generating power for future use without ever going to direct drive or shutting down the ICE. With proper software control of this system presented it could be done seamlessly without ever having clutch c3 and c2 engaged at the same time i.e. very smooth. It would go something like this in CS mode; at a stop light in mode 2 ICE running, light turns green step on the accelerator, c3 disengages completely mode1 (ICE still running) then the transition to mode 6, as a cruising speed is reached, back to mode 1 then c3 reengages mode 2 the ICE will only be free running for a very short time. Remember all this can be done in milliseconds (clutch reaction time dependant) with just the right timing. Also if GM is correct in stating that the ICE will be run at selected RPM’s you would never connect clutch c3 and c2 at the same time mode3. That being said with this platform anything is possible and during testing they probably tried both approaches; both series with a fixed rpm points and parallel with c3 and c2 engaged with varying rpm’s and found that the series method was more efficient. What I am trying to say is from a testing perspective this is a very advanced system and I believe they are going to utilize it in its most efficient manner. i.e. not using direct drive but needed clutch c2 so M/G A could be used as both a motor and generator depending on time so that both M/G A and B could be reduced in size for efficiency reasons. Even if they are not using a mode 3 it was wise to include it in the design and patent, now they own the system. Not sure if this is what is being done but it is how I would do it if I was tasked with the Job.

    After looking at this, anyone who doubts the engineering that went into this system or its magnitude is crazy. It was extremely well thought out from a systems approach. I would say as an Engineer to the Volt Engineering team job well done on this platform!!

    Remember the delta wing aircraft were not really successful until computer control and fly by wire!!


  108. 108
    Loboc

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Sep 27th, 2010 (8:10 pm)

    Dave K.: Like I tell my wife when she catches me checking out a pretty girl. “My finger may be married, but my eyes are single”.

    If I tried to push that logic past my wife, I’d only have one eye left! So, yeah I guess that’d be a single at that point.


  109. 109
    solo

     

    Vote -1 Vote +1

    solo
     Says

     

    Sep 27th, 2010 (9:35 pm)

    I really want to see this bitch disassembled on a bench! I bet it looks like a Swiss watch, only bigger!


  110. 110
    JCook

    +1

     

    Vote -1 Vote +1

    JCook
     Says

     

    Sep 27th, 2010 (9:58 pm)

    herm: You got it!.. the generator motor is not really driving the wheels but is does change the gear ratio of the EVT gears. Once it goes into CS mode then the whole thing reverts to a fixed gear ratio.. if you step on the brakes the generator disengages (ICE shuts off) and you get an EVT again to extract the most energy possible from braking. In other words, the generator is not running when the Volt is braking. This also means the Volt is more efficient in CD mode than in CS mode, Alex made a mention of that.  (Quote)

    I completely agree here except the ICE would not need to shut off during this momentary changes i.e. agressive breaking or accelerating. The ICE would be better off still running and disengaging and reengaging c3.


  111. 111
    JCook

     

    Vote -1 Vote +1

    JCook
     Says

     

    Sep 27th, 2010 (10:06 pm)

    Van: I am pretty slow so I cannot discern much of a difference between this and Toyota’s HSD. Instead of MGA and MGB we have MG1 and MG2. Same sun, planet, ring gear configuration. It looks like the idea is to drop in some clutches and claim it does not infringe on existing patent rights. Hope it works, this system is too good to be kept from the competition.  (Quote)

    Flexibility through clutch control is the major dif and major advatage.


  112. 112
    koz

    +3

     

    Vote -1 Vote +1

    koz
     Says

     

    Sep 27th, 2010 (10:25 pm)

    Finally had time to read through the article. Thanks Cab Driver for the find and taken the time to put this together. I agree, this seems very likely to be the Volt’s drivetrain. I think it agrees with everything we have heard recently from GM, including the ever-controversial Mode 3 (output split). Please allow me to expound:

    -Everything Cab Driver says about the modes, plus…

    -Since MG/B is capable of max motive power, this allows great functionality to this arrangement

    -In Mode 2 & 5 and becuase M/G-B is capable of full power, M/G-A can be used to soft start the engine without any immediate for power

    -Even C2 and C3 are closed simultaneously, this does not contradict GM’s electric only statements (sort of, in a loose interpretation kinda way). I think the Volt will definitely use this mode in CS mode for relatively steady spead driving (perhaps only under cruise control). This motor “transmission” arrangement gives GM engineer a LOT of flexibility in how to most efficiently use the ICE in CS mode. Since power is always required from M/G-B, even if C2 & C3 are engaged, always GM to make the statement the Volt will always be electrically driven. While theoretically this may be considered misleading to some degree, practically who cares. If it makes the Volt more efficient, then it’s all good (except for system cost perhaps). Another thing is that, even in this mode 3, M/G-A could still be active drawing or adding power as needed (motors guys, feel free to jump in here to discuss the feasibility of this). This would be a more efficient means of keeping the ICE in steady-state operation during small transient load changes than using M/G-B for this buffering.

    -Never, ever close C1, C2, and C3. This would be one nasty bug.


  113. 113
    frank filter

    -1

     

    Vote -1 Vote +1

    frank filter
     Says

     

    Sep 27th, 2010 (10:31 pm)

    Lets get the facts straight Toyota didn’t invent hybrids or their HSD.

    Ford did and sold to Toyota ( by mistake)now I believe ford has to license some of the technology back to ford!

    Toyota has never invented anything from my understanding, copy yes. In fact on the new Lexus the heads up display was was a copy of the heads up used in GM cars of the 1990s.

    So when people say GM is like something you could go back to about 1910 or so and see hybrid cars then. Jay leno has one


  114. 114
    LRGVProVolt

     

    Vote -1 Vote +1

    LRGVProVolt
     Says

     

    Sep 27th, 2010 (10:35 pm)

    herm: CorvetteGuy: So, from a standing start, both electric motors are engaged to the wheels, but when the ICE comes online, one of them is disengaged and starts to generate electricity. So, in stop and go traffic, it would toggle back and forth based on how much power is needed to the wheels. Is that about right?

    You got it!.. the generator motor is not really driving the wheels but is does change the gear ratio of the EVT gears. Once it goes into CS mode then the whole thing reverts to a fixed gear ratio.. if you step on the brakes the generator disengages (ICE shuts off) and you get an EVT again to extract the most energy possible from braking. In other words, the generator is not running when the Volt is braking.

    This also means the Volt is more efficient in CD mode than in CS mode, Alex made a mention of that.

    I think that that is incorrect. From a standing start, the hybrid power train (10) would operate in serial mode wit only one motor. As explained one page one Summary of Invention [0006] states, “(EVT) is provided with …..a forward low range electric-only operating mode where the engine is off”. This mode would be for starting. Later in [0011], where disconnecting by means of clutch 3, a two motor mode that is “suitable for minimizing losses across both the first and second motor/generators and for reducing an operating speed of the second motor/generator.” This two motor electric only mode reduces heat losses in the motor making it more efficient.

    [0016] The second motor/generator, (82) in the diagram, is continuously connected to the sun gear(node 1) . The carrier member (node2) goes to the output member, while the first motor/generator, (80) in the diagram, is selectively connected to the ring gear (node3). This arrangement is different from the first and subsequent HSD generations.

    220px-THS_evol_1.png

    Happy trails to you ’til we meet again.


  115. 115
    JCook

     

    Vote -1 Vote +1

    JCook
     Says

     

    Sep 27th, 2010 (10:37 pm)

    koz: Finally had time to read through the article. Thanks Cab Driver for the find and taken the time to put this together. I agree, this seems very likely to be the Volt’s drivetrain. I think it agrees with everything we have heard recently from GM, including the ever-controversial Mode 3 (output split). Please allow me to expound:-Everything Cab Driver says about the modes, plus…-Since MG/B is capable of max motive power, this allows great functionality to this arrangement-In Mode 2 & 5 and becuase M/G-B is capable of full power, M/G-A can be used to soft start the engine without any immediate for power-Even C2 and C3 are closed simultaneously, this does not contradict GM’s electric only statements (sort of, in a loose interpretation kinda way). I think the Volt will definitely use this mode in CS mode for relatively steady spead driving (perhaps only under cruise control). This motor “transmission” arrangement gives GM engineer a LOT of flexibility in how to most efficiently use the ICE in CS mode. Since power is always required from M/G-B, even if C2 & C3 are engaged, always GM to make the statement the Volt will always be electrically driven. While theoretically this may be considered misleading to some degree, practically who cares. If it makes the Volt more efficient, then it’s all good (except for system cost perhaps). Another thing is that, even in this mode 3, M/G-A could still be active drawing or adding power as needed (motors guys, feel free to jump in here to discuss the feasibility of this). This would be a more efficient means of keeping the ICE in steady-state operation during small transient load changes than using M/G-B for this buffering.-Never, ever close C1, C2, and C3. This would be one nasty bug.  (Quote)

    This sounds likeit is definately possible ICE still running and engaged but electrical being supplied to M/G A for added power, so the link is there but the ICE is not supplying energy at this time effectively (still running). If this were true though there would be no reason to not disengage c3(ice still running). Power wise it’s the same thing. See my post #107. It’s a wonderfully flexible platform.


  116. 116
    JCook

     

    Vote -1 Vote +1

    JCook
     Says

     

    Sep 27th, 2010 (10:55 pm)

    LRGVProVolt: I think that that is incorrect. From a standing start, the hybrid power train (10) would operate in serial mode wit only one motor. As explained one page one Summary of Invention [0006] states, “(EVT) is provided with …..a forward low range electric-only operating mode where the engine is off”. This mode would be for starting. Later in [0011], where disconnecting by means of clutch 3, a two motor mode that is “suitable for minimizing losses across both the first and second motor/generators and for reducing an operating speed of the second motor/generator.” This two motor electric only mode reduces heat losses in the motor making it more efficient. [0016] The second motor/generator, (82) in the diagram, is continuously connected to the sun gear(node 1) . The carrier member (node2) goes to the output member, while the first motor/generator, (80) in the diagram, is selectively connected to the ring gear (node3). This arrangement is different from the first and subsequent HSD generations.Happy trails to you ’til we meet again.  (Quote)

    I’m not sure I get what you are stating here but something doesn’t seem right. It seems a little contradictory.

    You statev”From a standing start, the hybrid power train (10) would operate in serial mode wit only one motor.”

    Then”“(EVT) is provided with …..a forward low range electric-only operating mode where the engine is off”. This mode would be for starting.”

    EVT(dual motor) and single motor modes are two different things but you say they are both for starting. If I am reading this wrong please let me know as I think Corvette Guy was correct in a large way.


  117. 117
    LRGVProVolt

     

    Vote -1 Vote +1

    LRGVProVolt
     Says

     

    Sep 27th, 2010 (11:54 pm)

    JCook:
    I’m not sure I get what you are stating here but something doesn’t seem right.It seems a little contradictory.You statev”From a standing start, the hybrid power train (10) would operate in serial mode wit only one motor.”Then”“(EVT) is provided with …..a forward low range electric-only operating mode where the engine is off”. This mode would be for starting.”EVT(dual motor) and single motor modes are two different things but you say they are both for starting.If I am reading this wrong please let me know as I think Corvette Guy was correct in a large way.  

    I sighted the paragraphs that led to my conclusion. Corvette Guy stated: “So, from a standing start, both electric motors are engaged to the wheels.”

    I don’t agree with that. The patent, in several locations, talks about the two motor mode. Paragraph [0011] states “that a two motor mode suitable for minimizing loses across both of the first and second motor/generators and for reducing an operating speed of the second motor/generator.” When starting, the primary propulsion comes from the second motor/generator, the one continuously connected to the Planetary Gear. At the slow speeds at start up, there is no need to reduce its operating speed. It makes sense that only one motor is needed at startup. At higher speeds the second motor/generator can kick in to provided the necessary torque to accelerate, plus increase efficiency of the primary motor/generator by reducing the friction of high rpm.

    Check out the end of Paragraph [0019]: “Engagement of the first torque transmitting mechanism (c1) and disengagement of the second torque transmitting mechanism (c2) establishes an electric -only mode in which the input member does not rotate and the second motor/generator acts as a motor utilizing power from the recharged energy storage device to provide torque to the output member.”

    This description is exactly how the Volt operates with the exception that it has been repeatedly stated that the motor /generator provides current directly to the traction motor, not the energy storage device. This description is similar to how the EV Silverado that Raser Technology is selling to utilities.

    I believe we will see this EVT used in GEN2. Maybe GM is installing it in a few of the GEN1 Volts and having early adopters test it.

    Happy trails to you ’til we meet again.


  118. 118
    LRGVProVolt

     

    Vote -1 Vote +1

    LRGVProVolt
     Says

     

    Sep 28th, 2010 (12:00 am)

    JCook: EVT(dual motor) and single motor modes are two different things but you say they are both for starting.

    Also, I did not say “both for starting.” That was said by Corvette Guy.

    Just a little correction. :)

    Happy trails to you ’til we meet again.


  119. 119
    LRGVProVolt

     

    Vote -1 Vote +1

    LRGVProVolt
     Says

     

    Sep 28th, 2010 (12:18 am)

    Cab Driver:
    Clutch C1 stops the Ring gear from rotating when it is engaged and C2 is disengaged. This causes any power from M/G B to be sent to the Final Drive with a fixed gear ratio when in Mode 1: 1 Motor Electic-only or Mode 2: Series.  

    I was going to reply to Alexander but you beat me to it. :)

    There has been at least one post that stated that c1 and c2 would be engaged. Thanks for pointing out that C2 would have to be disengaged when c1 is engaged!

    Happy trails to you ’til we meet again.


  120. 120
    LRGVProVolt

     

    Vote -1 Vote +1

    LRGVProVolt
     Says

     

    Sep 28th, 2010 (12:35 am)

    Van: I am pretty slow so I cannot discern much of a difference between this and Toyota’s HSD.Instead of MGA and MGB we have MG1 and MG2.Same sun, planet, ring gear configuration.It looks like the idea is to drop in some clutches and claim it does not infringe on existing patent rights.Hope it works, this system is too good to be kept from the competition.  

    See my post #114 wherre I show the diagram of the first HSD. The GM EVT is totally different. The second motor/generator is connected directly to the sun gear; the first motor/generator is selectively connected to the ring gear; and the carrier member is connect to the output member. If you look at the diagram for the HSD, you can readily see a big differnece. I don’t think GM will have a problem with this patent.

    Happy trails to you ’til we meet again.


  121. 121
    Sean

     

    Vote -1 Vote +1

    Sean
     Says

     

    Sep 28th, 2010 (1:08 am)

    Wow this article was hard to understand could you describe it in a way that I could understand it and no I don’t know advance math at all period! Thanks for listening.


  122. 122
    kForceZero

     

    Vote -1 Vote +1

    kForceZero
     Says

     

    Sep 28th, 2010 (1:08 am)

    Why are my comments not showing up? Odd. I tried posting earlier and my comment didn’t show up. I tried posting again and it gave me a “duplicate comment” error but the comment still didn’t show up. Anybody have this happen before?


  123. 123
    Matthew B

     

    Vote -1 Vote +1

    Matthew B
     Says

     

    Sep 28th, 2010 (1:10 am)

    herm: To some degree it sounds like HSD, but so does Ford’s system and they have their own patents.. the original design was by a TRW engineer in the late ’60s I believe

    Herm beat me to it. The reason Toyota wasn’t able to do squat when they went after Ford is because Toyota only re-patented a 35 year old idea.


  124. 124
    koz

     

    Vote -1 Vote +1

    koz
     Says

     

    Sep 28th, 2010 (7:08 am)

    koz: -Even C2 and C3 are closed simultaneously, this does not contradict GM’s electric only statements (sort of, in a loose interpretation kinda way). I think the Volt will definitely use this mode in CS mode for relatively steady spead driving (perhaps only under cruise control). This motor “transmission” arrangement gives GM engineer a LOT of flexibility in how to most efficiently use the ICE in CS mode. Since power is always required from M/G-B, even if C2 & C3 are engaged, always GM to make the statement the Volt will always be electrically driven. While theoretically this may be considered misleading to some degree, practically who cares. If it makes the Volt more efficient, then it’s all good (except for system cost perhaps). Another thing is that, even in this mode 3, M/G-A could still be active drawing or adding power as needed (motors guys, feel free to jump in here to discuss the feasibility of this). This would be a more efficient means of keeping the ICE in steady-state operation during small transient load changes than using M/G-B for this buffering.

    I should have also stated that from a pure technical sense, GM can claim series hybrid since the ICE power always flows through M/G-A. Again, not that the semantics mean much. The important factors are efficiency, reliability, and cost. I’m guessing future improvements in motors, controls, batteries, and range extenders will render the added cost of this “electrically variable transmission” unnecessary.


  125. 125
    JeremyK

     

    Vote -1 Vote +1

    JeremyK
     Says

     

    Sep 28th, 2010 (7:47 am)

    This is interesting:
    I just checked my order status and they have changed the powertrain description from the one mentioned above (EVT transmision, etc) to this:

    Powertrain

    * Electric Drive Unit
    * 16 kWh lithium-ion battery
    * Range Extender. 1.4L Internal Combustion Engine


  126. 126
    JCook

     

    Vote -1 Vote +1

    JCook
     Says

     

    Sep 28th, 2010 (7:54 am)

    LRGVProVolt: I sighted the paragraphs that led to my conclusion. Corvette Guy stated: “So, from a standing start, both electric motors are engaged to the wheels.”I don’t agree with that. The patent, in several locations, talks about the two motor mode. Paragraph [0011] states “that a two motor mode suitable for minimizing loses across both of the first and second motor/generators and for reducing an operating speed of the second motor/generator.” When starting, the primary propulsion comes from the second motor/generator, the one continuously connected to the Planetary Gear. At the slow speeds at start up, there is no need to reduce its operating speed. It makes sense that only one motor is needed at startup. At higher speeds the second motor/generator can kick in to provided the necessary torque to accelerate, plus increase efficiency of the primary motor/generator by reducing the friction of high rpm. Check out the end of Paragraph [0019]: “Engagement of the first torque transmitting mechanism (c1) and disengagement of the second torque transmitting mechanism (c2) establishes an electric -only mode in which the input member does not rotate and the second motor/generator acts as a motor utilizing power from the recharged energy storage device to provide torque to the output member.”This description is exactly how the Volt operates with the exception that it has been repeatedly stated that the motor /generator provides current directly to the traction motor, not the energy storage device. This description is similar to how the EV Silverado that Raser Technology is selling to utilities.I believe we will see this EVT used in GEN2. Maybe GM is installing it in a few of the GEN1 Volts and having early adopters test it.Happy trails to you ’til we meet again.  (Quote)

    Read your post carefully it does say from start both times becuaese you said EVT in relation to start this is both motors like CorvetteGuy stated. Also speed is not as large a factor to determine power required acceleration is. From a start a lot of power is required. Constant speed would only require the main motor. I think you are interprting the patent incorrectly.


  127. 127
    Carcus3

     

    Vote -1 Vote +1

    Carcus3
     Says

     

    Sep 28th, 2010 (9:25 am)

    koz:
    I should have also stated that from a pure technical sense, GM can claim series hybrid since the ICE power always flows through M/G-A. Again, not that the semantics mean much. The important factors are efficiency, reliability, and cost. I’m guessing future improvements in motors, controls, batteries, and range extenders will render the added cost of this “electrically variable transmission” unnecessary.  

    Reminds me of “it depends on what the meaning of the word ‘is’ is….”


  128. 128
    EricLG

    -1

     

    Vote -1 Vote +1

    EricLG
     Says

     

    Sep 28th, 2010 (12:36 pm)

    This arrangement is different from the first and subsequent HSD generations.

    The schematic should flip MG2 and the mechanical connection to the wheels.


  129. 129
    koz

     

    Vote -1 Vote +1

    koz
     Says

     

    Sep 28th, 2010 (4:23 pm)

    Carcus3:
    Reminds me of “it depends on what the meaning of the word ‘is’ is….”  

    Which sounds like just about the same as corporate speak produced by every other major corporation as well.


  130. 130
    usbseawolf2000

     

    Vote -1 Vote +1

    usbseawolf2000
     Says

     

    Sep 28th, 2010 (5:00 pm)

    Missed this post by a day.

    This thing has 3 clutches and a planetary gearset. I hate to do it but I told you so! Some of you were in the state of denial. It must be a really hard wakeup call. Sure, rate me down for saying the truth.

    This is more complex than Toyota HSD. More complex than Hyundai Blue Drive (1 clutch 2 MGs). More complex than Nissan Direct Drive (2 clutches 1 MG). It has trait and complexity of all three combined. It would be an engineering nightmare. I hope they work out all the bugs.

    The only good thing I can say about it is that it is flexible. Too flexible. You don’t really need C3. What happened to keeping it simple, stupid?

    This thing has 3 clutches and 3 coolants to maintain. Wasn’t it supposed to be a simple electric car with range extender?

    The look of the concept was changed. Then the price. Then operation modes were added. Now the drivetrain is completely out-of-this-world.


  131. 131
    usbseawolf2000

     

    Vote -1 Vote +1

    usbseawolf2000
     Says

     

    Sep 28th, 2010 (5:06 pm)

    AT-PZEV emission standard was not met resulting in HOV lane denial. Flex Fuel E85 capability was dropped. Premium fuel is now required. We are still waiting for the MPG on the CS mode. It is about a month away from the launch.


  132. 132
    Bob G

    +1

     

    Vote -1 Vote +1

    Bob G
     Says

     

    Sep 28th, 2010 (5:53 pm)

    Jim: Jim Says

    Sep 27th, 2010 (8:02 am)

    WHAT???, This is not anywhere close to the drive train I have been reading about for the last 3 years. We have heard it many times from Lyle’s post that the ICE is in now way connected to the wheels. This looks like a patent for a strong hybrid not the simple Voltec design that makes it so appealing.

    [ICE]===[Generator]——[Battery]—–[Power Control]—-[Drive Motor]====[Wheels]

    ==== Mechanical drive shaft
    ——- Electrical Wires

    This is going to confuse alot of people.

    Yep. Everything I have heard from GM in the last few years is consistent with your ASCII diagram … All electric, all the time from the single drive motor. No mechanical connection between the ICE and the wheels.

    Probably some GM engineer came up with a nifty idea and got a patent. It happens all the time, but a patent doesn’t mean that GM is actually building them.

    This discussion might be good FUD for GM’s competition though.


  133. 133
    Brian

     

    Vote -1 Vote +1

    Brian
     Says

     

    Sep 28th, 2010 (6:14 pm)

    Very similar to a design by Jaguar, for a power spliting gear box for four wheel drive but the other way round. They used it to change the power split from front wheel driver 80/20 to rear wheel drive 20/80 as the gear box up shifted with speed. Better to just put the electrice motors in the wheels and dump all this weight and complexity. The motors would be the brakes as well.


  134. 134
    Paul Stoller

     

    Vote -1 Vote +1

    Paul Stoller
     Says

     

    Sep 28th, 2010 (11:34 pm)

    Brian: Very similar to a design by Jaguar, for a power spliting gear box for four wheel drive but the other way round. They used it to change the power split from front wheel driver 80/20 to rear wheel drive 20/80 as the gear box up shifted with speed. Better to just put the electrice motors in the wheels and dump all this weight and complexity. The motors would be the brakes as well.  

    We will eventually get there, but currently unsprung mass is still an issue. There are some new motor designs that may cut the unsprung mass to acceptable levels but I’m not sure we are there yet. At least at competitive prices.


  135. 135
    Mohsen

    +1

     

    Vote -1 Vote +1

    Mohsen
     Says

     

    Oct 1st, 2010 (2:46 am)

    Told you so a long time ago – Volt has parallel capability. This is the “Output Split” mode 3.

    By itself this is not a bad thing – but to call the Volt “pure serial” is incorrect.

    Parallel mode is a MUST in the Volt. M/G B is only 50 KW (or 55?). That is not enough to pass on highways or to hillclimb or to tow.

    Thus in CS mode, where there is no juice in the battery, you need this parallel coupling.

    Furthermore, the planetary gearset allows the two M/Gs to operate at lower speeds compared to a pure serial.

    However, I still believe that a pure serial with an oversized (100 KW) M/G A and 100 KW M/G B is superior to this EVT with undersized M/G. Expect this EVT serial/parallel to go the way of the dodo.