• 71
2011 Chevrolet Volt – Click above for high-res image gallery

Let's get one thing perfectly clear: the 2011 Chevrolet Volt does NOT have a direct mechanical connection between the engine and wheels. Ever since a report last week in the Telegraph indicating that the Volt/Opel Ampera could drive the wheels directly at highway speeds, this controversy has started to bubble up.

After HybridCars.com spoke with GM spokesman Rob Peterson, the waters were simply muddied further. The site's editor asked Peterson a hypothetical question about what could be done to maximize the Volt's efficiency. Unfortunately, some context was left out in the write-up of Peterson's response. AutoblogGreen checked directly with Peterson on Tuesday evening. The question was essentially this: if driving the wheels directly the way current hybrids do could improve efficiency, would that be possible in the Volt. Peterson told ABG that in general, the engineers would do whatever they felt was necessary to maximize efficiency including direct-drive if they thought that was the answer.

However, the basic architecture of the Voltec powertrain has not been changed since it debuted in 2007 and the engine is only connected to the generator. There is currently no mechanism to drive the wheels even if the engineers wanted too. If they felt that was the best solution, they would have to re-engineer the entire drive system. Having said that, there are control strategies originally developed as part of the two-mode hybrid program that are in use in the Volt and lessons learned from other development efforts have been applied to this new car.

As for the case of Andrew English of the Telegraph in the UK, apparently a technician whose job is to take care of the cars and shuttle them around was the source of the original erroneous story. The technician was not actually familiar with the inner workings of the Voltec system and was not authorized to speak about it.

Ultimately, this all comes down to people's obsession with labels. If we didn't insist on categorizing everything, it's likely none of this would have ever come up because in the end it only matters if the system works.


  • 11/29/09 7:17:39 -- Los Angeles, CA, U.S.A Vehicle Chief Engineer Andrew Farah and the new Chevy Volt during the Dodger Stadium ride and drive.


I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.


    • 1 Second Ago
  • 71 Comments
      • 4 Years Ago
      In short.... the Volt/Ampera "uses clutches and a planetary gear system" BETWEEN THE TWO ELECTRIC MOTORS ONLY. The ICE is not involved.

      One of these motors is called the traction motor. It is always connected to the wheels and is only ever used as a motor.

      The second motor is called the Motor/Generator. It serves two roles.
      When in "charge sustainment mode. It acts as a generator.
      When in EV mode, it usually does nothing. However, it CAN also act as a second motor. The MOTOR (not the ICE) is connected to the wheels via a planetary gear along with the traction motor. Providing a greater efficiency.
        • 3 Months Ago
        To clarify... this does NOT mean that the Volt is a parallel hybrid of any sorts.

        A parallel hybrid means that 2 individual sources of power are connected to the wheels in parallel. But the ICE is not connected to the wheels... EVER!.

        ***2 electrical motors connected to the wheels in this configuration is analogous to an EV with hub motors.***

        1 battery (the source) electrically connected to 2 or more electric motors mechanically driving the wheels.

        When the ICE is running (CS Mode)... The Volt is still a Series Hybrid! Since the mechanical energy produced by the ICE MUST, I repeat, MUST be converted to electricity and fed through the electrical motor. As it has always been known.
        • 3 Months Ago
        I take back my last statement: some power could indeed be coming from the battery as you state. But this doesn't change the fact that if the generator is mechanically connected to the wheels, the ICE must also be. It's unavoidable.

        This is all much ado about nothing. Except for the UK Telegraph article, everything I have read about the Volt has described it as a series hybrid configuration. The answers that Alex gave you in the interview are cryptic and seemingly nonsensical at times, but it's an unjustified leap to take what he says and assume a mechanical connection between the generator and wheels.
        • 3 Months Ago
        Joe, I see nothing in your conversation about planetary gears or clutches. And Alex says nothing about the electric machine coupled to the ICE being mechanically connected to the wheels. It is strange when he says, "in certain states its (sic) better to operate both to propel the vehicle and in some states its (sic) better to utilize more of the generator and less of the traction motor." But I think that in the next sentence clarifies it a bit "In some states its (sic) more efficient to use more of the generator and have more of the traction motor actually be a generator. That would be for example in coast down situation often we use our traction motor as a generator on regen." The way I read that is that the traction motor is used to capture regenerative braking energy and the generator is sending electrical energy to the battery, and not that the generator that is coupled to the ICE is mechanically connected to the wheels.

        A mechanical connection between the wheels and generator is possible, but that means that the ICE, which is inarguably mechanically connected to the generator, MUST BE also mechanically connected to the wheels. You can't have one without the other here. Since all of the mechanical power in such a situation originates from the ICE, this would be a power-split configuration.
        • 3 Months Ago
        @ Jeff

        http://gm-volt.com/2009/11/09/engineering-design-of-the-chevy-volts-two-electric-motors/

        -Alex Cattelan who is the Volt’s Chief Powertrain Engineer.

        He said it in November 2009, not me.

        ---------------------------

        The reason that 2 motors mechanically connected is better than 1 motor is because of the loss of torque at the high end of motors RPM band.

        The Problem:
        Poor acceleration at higher speeds (70+ mph) while in "EV Mode" (ICE NOT RUNNING).

        The Cause:
        A single Traction Motor spinning close to the upper RPM limit... has much less torque (needed for acceleration). The problem is NOT getting power to the motor, but in the motors ability to convert that power to rotational force (torque) at very high RPM.

        The Solution:
        "but what it does is optimize the rotating speed and the losses of the motors so in certain states its better to operate both to propel the vehicle and in some states its better to utilize more of the generator and less of the traction motor. In some states its more efficient to use more of the generator and have more of the traction motor actually be a generator. That would be for example in coast down situation often we use our traction motor as a generator on regen.
        We do have the ability to utilize both motors in propulsion mode."

        Using 2 motors connected mechanically through a planetary gear system... each motor can operate at lower RPM but without sacrificing Power.

        ------------------

        Sometimes the Simplest design does not provide the best efficiency for every situation.

        For the Layman, it is easy to understand the simplicity and therefore advocate that simplicity is the ONLY solution...

        ... but reality is filled with a diverse realm of situations. And engineers need to design a drivetrain that can be the best of both (or all) world. And that often leads to complexity.
        • 3 Months Ago
        Jeff.... I apologize for being unclear (and not thoroughly citing the speaker). That was not MY conversation with Alex Cattelan but a conversation he had with Lyle from GM-Volt.com

        - "I do have some mechanisms to couple those motors and in some points of operation these two motors can be coupled and have a more efficient state."

        http://gm-volt.com/2009/11/09/engineering-design-of-the-chevy-volts-two-electric-motors/

        That was from November 2009

        *** Notice the use of the term, "mechanism". Most people on the forum there assumed that it was an "electrical connection" only. But "mechanism" is supposed to strictly mean a mechanical device. ***

        But that is not certain from just that one quote. Read the below statement that confirms Alex's literal meaning.

        ---

        More recently, after this whole thing blew up as controversy, Lyle called up Rob Peterson to confirm some information.

        "I had checked in with Rob Peterson who said the claim was untrue and unfounded, and is not the case. Rob explained to us the Volt uses clutches and a planetary gear system to maximize performance and efficiency."

        This confirms that the PARTs in question do exist in the Volt.

        ------------

        Regarding your observation that a mechanical connection between the Gen/Motor and the wheels denotes that a mechanical connection between the ICE and the wheels exists.

        Yes, it could. And THAT, I believe is the source of all this confusion and controversy. This is what the Telegraph reporter mistakenly assumed.

        This is why there are at least 2 "clutches". One clutch to connect the Gen/Motor to the mechanical coupling of the Traction Motor (planetary gear)... and One clutch to disconnect the Gen/Motor from the ICE.

        So, the quote " saying it was theoretically possible but the author left out the part where he said it wouldn't."

        .... makes perfect sense.

        The Volt drive train is still set up as a series hybrid by very definition.
        • 3 Months Ago
        Where are you getting this talk of a planetary gear and clutches between the generator and traction motor? What purpose would these components serve? You understand that the generator transmits only electrical energy to the traction motor, right?

        There is no mechanical connection between the two electrical machines whatsoever, and it would make zero sense if there was (the generator converts the ICE mechanical energy to electrical energy--if there is to be a mechanical connection to the traction motor, there is no reason to have the generator, and then we are talking parallel hybrid here). The Volt is a series hybrid, and as NmGfan explained nicely, the odds that GM has changed things so drastically are very slim, and a couple of poorly researched newspaper articles just aren't very convincing.
      • 4 Years Ago
      the more I look into it and think about it the more I'm afraid that teh Volt has a prius style planet gear power split device modifed with a clutch so the electric drive motor can power the car free of the rest unlike a prius.
      Andreas Voigt probably weren't kidding when he said the Volt can already run on the ICE mechanically. it probably can. only a matter of software change. the mechanical layout of there already.
      Alex Cattelan (woman Volt chief drivetrain engineer) has said that the generator motor can be used to drive the car together with the drive motor. such a possibility would never exist in a true series hybrid it because the generator is connected to the ICE then it stands to reason the chain is there for the ICE to drive the wheels mechanically. she claimed she couldn't be clearer because it was 'proprietary' which is a fucking lie.
      GM's Peterson also said 'the Volt has a number of clutches'.

      Voigt's statement about intellectual property rights also hints at a prius style planet gear mechanical coupling which is a patent held by Paice. something a low level car babysitter wouldn't know anything about.

      GM has been deceiving us about the Volt. Disgusting. I suppose we shouldn't be surprised.
        • 3 Months Ago
        @Dan:

        Anything COULD be configured to be whatever you want it to be. The Prius COULD be configured to be a BEV...an ICE car could be configured to be a BEV (and vice versa). It's just a matter of what hardware you put into it. You clearly have no idea what hardware is going into it, so don't spit off like you know.

        Just because it has a clutch doesn't mean that the ICE is mechanically connected to the wheels. It could be to decouple the ICE from the generator to spool up more quickly, or to warm up the engine for an extended period of time without spinning the generator motor. OR it could couple it to a gearset to multiply the revs and increase the power output. You or I have no idea what it's connected to, and probably won't until someone buys one and takes it apart.

        You really need to take off the horse-blinders that block out whatever you don't think of first. Your close-minded attitude is going to come back to bite you at some point...
        • 4 Years Ago
        Do you work really, really hard at being this cluelessly arrogant, or is it a genetic defect?

        I work for a supplier of development tools and have been working with various teams within GM on many different aspects of the Volt driveline, components, power management systems and batteries since the beginning.

        I have been in many labs and have ridden in the Volt, as well as in one of the Cruze mules that were used earlier in the development process.

        I am a degreed engineer, very well respected in my profession and can tell you that there is no way, nada, nothing in the drivetrain that supports this ludicrous statement - supposedly by a guy from Opel.

        Opel has done some market specific development for the Ampera, but all of the core development has been done in Warren and Milford, Michigan - so it is very likely that the engineer is confused or the reporter didn't record his statement properly.

        GM is working on a number of other drivetrain configurations for future vehicles that I will not disclose, but there is a good change that this person could have been confused or misinformed about which configuration is used in the Ampera.
        • 4 Years Ago
        Joe, you know I'm right. as always : )
        the very texts you quote mention planetary gears and clutches and you yourself make the conclusion that it's all closely connected.

        two motors, one ICE, one planetary gear. it has prius style power split device written all over it.
        and the german engineer Andreas Voigt talks about how it can be configured to drive the wheels from the ICE using the clutches GM's Rob Peterson confirms it has. rather lucky guess for a valet wouldn't you say...

        the simple truth might be that it's a prius style power train with a few clutches for flexibility and they wanted to keep that from us for PR reasons. probably made the idiotic conclusion that if we knew we wouldn't be able to tell it apart from a prius style vehicle...

        Lyle should grow a backbone and push them for the truth on this and then a series of interviews on why they chose this instead of the simple series hybrid config.
        if I had to guess I'd say they were too afraid to try something really new and instead modified what they had done before.

        and let's see a damn diagram of the thing.
        • 3 Months Ago
        Joe, hehe at times you are almost adorably stupid. but mostly it's tiresome.

        can you quote me as saying series hybrid is categorically better than prius psd when operating on ice?
        I believe I have said that the prius is good even clever for the prius type of operation, meaning a gas car. I think you confuse my statements of overall superiority of the series hybrid in that it can operate unfettered in BEV which is the most important mode. the prius is hampered in that mode and has to spin the MG1 as well as drive with the MG2 to keep the ICE out of the equation.
        I have also said, which might also have lead you to hold on to your current mistake because of mindless eagerness, that the prius should have been series hybrid from day one and that position I hold because it would then have naturally invited increasing battery capacity and let the buyers experience the true EV drive which would have lead to a much quicker electrification. I am open to the possibility that series hybrid is even better than prius PSD when running on gas but they would naturally be similar and I wouldn't expect significant difference there. in theory, should you suddenly gain a calm sober mind, you could go back and verify that this has been my position all along.
        you can also find statements from me that the prius could be adapted to acceptable plugin operation by adding a clutch so the drive motor can drive it free of the power split device. that surprisingly appears to be what the Volt is.
        if there is one mistake one might be able to attribute to me it would be negatively describing such a configuration but even that potential error wont stick to me because the true series has an advantage over that and that is layout freedom. the planetgear trifecta has to be mechanically coupled. series just needs wires.
        get a box of cleenex and start crying :)
        • 3 Months Ago
        - "Joe, and when it turns out that I am right will you admit it?" -Dan

        THAT is the arrogance that many of us are talking about. Right there. Using the word "when". It should say "if". If you turn out to be right.

        And yes, IF you turn out to be right, I will admit it. But you have no proof or evidence that you are right... and since you lack the ability for research.. you don't seem capable of providing any evidence for your claims.
        • 3 Months Ago
        Jason, when I first heard of the clutches I also considered if it could be a gearbox for the generator to run the electric generator at best rpm but that hypothesis doesn't fit the other things we now know, namely from Alex Cattelan that the generator can join with the drivemotor, that it has 'a number of clutches' and the Opel engineer's statement about the car being able to connect the ICE and the wheels.
        the article states "The move would be possible without major engineering as the planetary twin-clutch transmission already has a direct mechanical link between the engine and wheels"
        superficially you might think he doesn't know what he's talking about but with the confirmation from GM that it has planetary gear and clutches and that the generator can be connected to the drive motor, it really helps his credibility. if that was a shot in the dark about a car that's being promoted as an REEV he got really lucky..
        • 4 Years Ago
        http://gm-volt.com/2010/06/30/combustion-engine-does-not-and-will-not-turn-the-volts-driveshaft-ever-got-it/

        Recently there has been a lot of Internet controversey with at least a dozen articles covering a story out of the Telegraph in England. Of course, GM-Volt.com was the first to notice this claim and publish it, all the other sites followed.
        The author, Andrew English, claimed the 65% calibration version Ampera/Volt prototype seemed to have a flat torque curve at high velocity. He wrote that an engineer claimed GM was planning to correct this by connecting the gas engine driectly to the drivetrain. I had checked in with Rob Peterson who said the claim was untrue and unfounded, and is not the case. Rob explained to us the Volt uses clutches and a planetary gear system to maximize performance and efficiency.
        Despite this, English published a second report called “Volt Shock.”
        In this repert he outed his source. “We are considering driving the wheels directly from the petrol engine,” said Andreas Voight, an Opel project engineer. There are a number of different ways we could do it, but the whole thing is subject to some intellectual property rights negotiations so I can’t say any more,” said Voight. “You will see an announcement this autumn.”
        While that story may be shocking, it remains untrue. Sam Abuelsamid from Autobloggreen determined Voight is simply a technician whose job (?former) is to simply shuttle cars for journalists and who has no actual knowledge about Volt engineering. Know the type?
        Another bad piece of journalism came out fo hybridcars.com, who won’t even publish authors’ names. The anonymous author claimed an “exclusive” interview with Rob Peterson. In that interview Peterson’s comments were taken out of context and distorted to make it seem the Volt would act like a parallel hybrid in range extended mode. Peterson was simply saying it was theoretically possible but the author left out the part where he said it wouldn’t. Anything is possible.
        What many authors don’t know is that the Volt has two electric motors that can act either in parallel at times, in other cases one acts as the traction motor to drive the wheels and the other acts as a generator. The system uses 2-mode technology to determine which configuration is optimal for that driving moment. It never, however, includes a direct ICE to wheel configuration. For more deatils see my post with Volt powertrain engineer Alex Cattelan.
        Finally to put this all to rest, I asked Volt vehicle line director Tony Posawatz if any of this rumor was true, if the ICE ever drives the wheels.
        “No.” said Posawatz. “I don’t know how those folks got so confused.”
        Got it?

        -----------------------
        http://gm-volt.com/2009/11/09/engineering-design-of-the-chevy-volts-two-electric-motors/

        I had the following discussion with Alex Cattelan who is the Volt’s Chief Powertrain Engineer. It explains for the first time anywhere in more depth how the Volt’s two separate electric motors function.
        The design of the electric motor, is there a separate generator or does the motor itself just turn the other way and act as a generator?
        Very interesting question. There are two motors. One is considered the traction motor and the other one is the generator. However, and they are two motors, the traction motor is higher-powered and designed specifically to meet the traction requirements. The generator is designed to efficiently couple to the engine to generate what we need and match the efficiency band of the engine as much as possible in all the operating modes. So we look at that motor as coupled with the engine in system and then we also have a traction motor.
        Some of the interesting pieces though of this are, for example, in EV operation I have two motors on board and I typically use the traction motor only to drive the vehicle. However, I do have some mechanisms to couple those motors and in some points of operation these two motors can be coupled and have a more efficient state.
        Does that produce more power if they’re coupled?
        It’s actually not additive for power, it’s actually the way it’s architected, and a lot of this is proprietary so I canâ
        • 3 Months Ago
        [Will repost in your continued thread]
        Joeviocoe, why are you so instantly hostile toward me? Its almost like you dont even want to know the truth. No I am not Dan. And Dan, yes I know how it works, yes I know how it is laid out, but no I am not answering any questions since obviously according to Joeviocoe I have no credibility here (since credibility is measured in post count and blog membership time). Which is why I simply requested someone who Joeviocoe perhaps will give more credibility to (in this case anoldbikeguy) to see for themselves since they claim to have access to inside info. It seems that individual is perhaps bored with the topic though.

        And Joeviocoe, you caught me. I made up lever diagrams.
        http://tinyurl.com/2vvtg9m
        Try the first link.

        Anyway this is all a moot point. I think there is more agreement here than is realized. Joeviocoe by readin your posts you seem understand that a mechanical link can be engaged to allow the generator motor to deliver tq to the axle. I will quote you here:

        "The second motor is called the Motor/Generator. It serves two roles.
        When in "charge sustainment mode. It acts as a generator.
        When in EV mode, it usually does nothing. However, it CAN also act as a second motor. The MOTOR (not the ICE) is connected to the wheels via a planetary gear along with the traction motor. Providing a greater efficiency."

        So you understand that the ICE can be coupled to the motor generator. You also understand that the motor generator can be coupled to the axle. It follows then that the ICE through the motor generator can be *mechanically* coupled to the axle. Not necessarily that it does do this. But that it can. Engage the right clutches and there is a mechanical path from the ICE to axle. Regardless of whether or not this is ever done, you must understand that it is possible. It is controlled by the software. If desired, the software could do it.

        So hopefully now you understand it is possible. Now you need to understand it makes sense. Keep in mind this discussion relates only to charge sustainment mode. The Volt is still an electric vehicle first. Whether or not the drive train is series or parallel. A conventional vehicle typically gets much better highway efficiency. This is because an ICE is very in-efficient at low speeds/light torque. Therefore in the city where you are speeding up and slowing down, shifting, and throwing energy away to friction brakes it makes sense to decouple the engine from the axle. It need not worry about such harsh transients and low efficiency zones. Let it generate energy as needed and as demand rapidly changes let those transients be handled by storing and discharging the battery. In highway driving the ICE is running at or very near its peak efficiency. There is nothing to be gained from a series system. You are only throwing energy away by passing it through two motor inverters and possibly a battery. Just send the power straight to the axle.

        Not put yourself in GM's shoes. Knowing this, would you design a strictly series or strictly parallel architecture? The answer is neither. You design an innovative powertrain that is the best of both worlds. The capability of different operation modes to get the best efficiency all the time. The 2 mode, 4 mode, and erev transmissions are outstanding pieces of engineering. While I do criticize GM for not building more smaller strong hybrids the technology behind the 2 mode is still impressive. Make no mistake, the Volt is an outstanding product.

        So why continue to announce it is series only? Well many EV fans might be disappointed. I admit, when I first heard about the Volt I was excited and thought strictly series was the way to go. I was disappointed when I started hearing that there actually was a path from ICE to the wheels. A few years of industry experience later I understand why it is designed the way it is. Many others still wont understand. The would feel as I once did that the drivetrain is tainted if that nasty ICE has anything to do with the output shafts. Now I understand that with planetarys and good design you really can have the best of both worlds.
        • 3 Months Ago
        Mr. "Somebody", "Member Since Jun 30th, 2010"... only 1 post...

        We know it is you Dan. You can stop with your attempt at entrapment.


        ------
        1) Are we supposed to take your word for proof that this "lever diagram for the Volt transmission" exists?

        2) Are we supposed to take your word for proof that this "lever diagram for the Volt transmission" is really for the current Production Version of the Chevrolet Volt???...

        and NOT some iteration of a concept design or some other possible Voltec platform variation??? Such as GM’s FWD 2-mode transmission??
        http://www.che.ncsu.edu/ILEET/phevs/plug-in_2008/1A-1_GM%202-ModePHEV%20VUE.pdf

        and

        3) Are we supposed to take your word for proof that this "lever diagram for the Volt transmission" is not some confusion of the entire system??
        Some people might call the whole assembly of 2 electric motors, planetary gears, and clutches... as a transmission.

        The term Transmission, doesn't necessarily mean the conventional ICE design of either automatic or manual. Hell, even Toyota calls there single planetary gear PSD an E-CVT. I let you figure out what the "T" stands for.

        • 3 Months Ago
        Okay...I simply said that COULD be one possible solution, not that it WAS the solution. I don't automatically jump to only one possible solution to a problem, because there are many.

        What about unloaded warm-up? What about multiplying output rpm? Those could still be possible solutions. There are probably many more uses for a clutch in this vehicle than your or I could both think of that don't have to do with mechanically linking the ICE to the wheels. But again, you jump to the conclusion that there is only one possible solution to the problem, which is the number one no-no in the engineering world.
        • 3 Months Ago
        Joe, and when it turns out that I am right will you admit it? or haste on to the next mindless assault..
        • 3 Months Ago
        Joe, try short quotes or just the link. don't copy entire articles several times.
        • 3 Months Ago
        @ Dan

        Apparently you and Andrew English of the Telegraph in the UK have something in common.

        You both like to take quotes completely out of context to suit your needs.

        Do really need to use direct quotes again? Oh, I am talking to Dan F... of course I do.

        - "and not one of them is of a planetary gear transmission that can take power in parallel from the electric motor or the gasoline engine." -NmGfan

        NmGfan was not denying the existence of planet gears or clutches. Just that there are none, "that can take power in parallel from the electric motor or the gasoline engine"

        Just as nobody is denying the existence of your brainpower... just that your brainpower is not used often.

        ------------------

        You are still writing nonsense without ever backing up your claims with anything. Take a direct quote, link some websites or interviews... something.

        Do you even know how to cut and paste in a web browser?
        • 4 Years Ago
        - " In that interview Peterson’s comments were taken out of context and distorted to make it seem the Volt would act like a parallel hybrid in range extended mode. Peterson was simply saying it was theoretically possible but the author left out the part where he said it wouldn't."

        This statement leads me to think that the SAME set of clutches that connects the Motor/Generator to the Traction Motor (via planetary gears) also disconnects the ICE from the Motor/Generator.

        So, in essence. The Volt does NOT EVER use a parallel hybrid setup.
        1) Because, when using the planetary gear, the source of power is still 100% electric. Only using 2 motors. But no ICE.
        2) And, when using the ICE, the source of power follows the series pathway that we are familiar with.
        • 3 Months Ago
        @ anoldbikeguy

        Dan will not let a little thing like ignorance stop him from speaking his mind and calling it enlightenment.


        @ Dan F
        Nobody here is denying that the Volt will have planet gears or clutches. That is a straw man that you have created so you can look smart.

        And I have made no such conclusion that "it's all closely connected".... As if I agree that it has anything to do with Toyota's HSD configuration.



        You are just getting angry because the Volt drivetrain wasn't the hallmark of simplicity you thought it was.

        First, you find out that the Prius is more efficient than the Volt during CS Mode...

        And now, you find out that your "perfect understanding" of the engineering principles of the Volt drivetrain is not correct.

        Is your world crashing down?

        Next thing you know... it will be revealed that the GM Ultralite that you worship so much... is nothing more than Hollywood special effects. Ouch!
        • 3 Months Ago
        - "I've known how the prius PSD works for years" -Dan

        You only THINK that you knew...
        Just like you THOUGHT you knew how the Volt drivetrain worked too. OUCH!!! Too soon?

        But you have always held the idea that hybrids like the Prius, are less efficient than series hybrids because they operate MUCH wider range of RPMs like a normal non-hybrid ICE engine would. WRONG!

        Everyone told you that you were wrong but you just called them "mindless" and ignored the...

        But I showed you proof (albeit I got confused as to which hybrid you were all talking about). Then, you proceeded to link that same "proof" that I showed you... in a piss poor attempt to say the Volt had the same drivetrain. WRONG AGAIN!

        --------------------

        Quit deflecting and admit to everyone that you were wrong... big time... twice.

        Suddenly, I "don't deserve any response" from you??? You have always responded. What has changed?

        Oh, you got owned, thats what. So now you want to be the silent type.

        Just admit your faults for once in your life and break your cycle of arrogant denial. Go find some ounce of humility.
        • 3 Months Ago
        Well Dan, since you never seem to click on any of the links I post to you as evidence for my side of the argument... I thought maybe you didn't know how to click on links.

        I had to post http://eahart.com/prius/psd/ 2 or 3 times before you actually read the information. Then you ignored part about how the Prius' ICE can run at a constant, optimum, speed for greater efficiency. Because it didn't fit with your preconceptions of the Prius's ICE being a huge loss compared to the fantastical Volt ICE.

        -----------------

        http://gm--volt.com/2009/11/23/engineering--design--and--efficiency--of--chevy--volts--generator--mode--builds--on--gms--two--mode--hybrid--technology/

        BTW.... still waiting on those two admission of errors.
        • 4 Years Ago
        Dan,
        I would put a little more stock in what an engineer working directly on the project has to say rather than some confusing contradictory Telegraph article. There are plenty of photos of the various components going into the Volt/Ampera drive train all over the web, and not one of them is of a planetary gear transmission that can take power in parallel from the electric motor or the gasoline engine. Nor is there any evidence that a multi-gear "shiftable" transmission is connected directly to the ICE, a necessity with such a tiny (1.4liter) displacement naturally aspirated engine in a heavy sled like the Volt (3500lbs?). I doubt seriously that GM would allow this type of technical detail to be "leaked" over in the UK as a precursor to a major technology shift that the Volt is really just a Prius in GM clothing.
        Step back and look at the much larger body of evidence that the Volt will be exactly what GM said it would be, an electric vehicle with 40 miles battery only range that has an on-board ICE connected DIRECTLY to a generator that can recharge the batteries and/or move the vehicle down the road as a Gasoline-Electric drive.
        Anything is possible in future vehicle variants, but it is highly improbable that GM will make a major drive train change less than six months before market launch... Seriously, over three years from concept to now around 100 pre-production engineering models all over the roads in America and then "Hey, it'll be something completely different that we haven't prototyped or tested, but will release to the public in November 2010, Ha Ha!". Just ask the guys across the pond, they had nothing to do with developing or manufacturing the product, but there is this article in the Telegraph that so and so says blah, blah, blah contradicting everything GM ever said about the Volt. Right!
        • 4 Years Ago
        no there isn't.
        first, do you actually know precisely how the Volt drivetrain is laid out?
        and are you aware that GM's mr Peterson stated 'the Volt has a number of clutches'? care to explain what those are for?
        are you also aware that the chief Volt drivetrain engineer Alex Cattelan has said that the generator motor can be set to drive the car in combination with the primary drivemotor. care to explain that?
        we are not talking about just some guy from Opel
        • 4 Years Ago
        Dan et al -

        Sorry for the late response - I have been at the GM Milford Proving Grounds all afternoon enabling them to expand upon their model-in-the-loop development endeavours.

        (Takes a dump and eats dinner while Dan researches what MIL is).

        Dan - while I respect your dedication to adopting greener transportation in the US, you have to understand that without an engineering education and background you are totally unqualified to critique any OEM's efforts in this area.

        You have some modicum of intelligence - I have seen this in a minority of your posts - get yourself into an engineering program if you want to make a difference!
        • 3 Months Ago
        Dan Fredericksen....

        Are you ready to admit you were wrong?

        You were wrong on 2 things:

        1) The current model Toyota Prius (with its HSD Power Split Device) IS more efficient than the Chevy Volt running in Charge Sustainment Mode

        2) The Chevy Volt will NOT have it's ICE directly and mechanically driving the wheels.

        *** All the proof you need, is right here in this interview of Alex Cattelan, the Chevy Volt’s chief powertrain engineer:

        1) Alex admits that the Volt's CS Mode is less efficient than the Prius... but the Volt was "optimized" for EV Mode.

        2) Alex specifically says, "...decouple the engine or generator from the axle torque requirement.." and explains why that is important. That also explains the need for a few "Clutches".


        We here at ABG await your humble admission of error.



        ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

        http://gm--volt.com/2009/11/23/engineering--design--and--efficiency--of--chevy--volts--generator--mode--builds--on--gms--two--mode--hybrid--technology/

        From Lyle @ GM--Volt.com
        Nov. 23rd 2010

        --I had a discussion with Alex Cattelan, the Chevy Volt’s chief powertrain engineer about the engineering design and operation of the Chevy Volt’s charge sustaining mode. This is the mode that occurs after the car has depleted the first 40 miles of range and the gas generator has begun providing electric power.

        --When you first unveiled the Volt and it was a math model, the car was promoted as getting 50 MPG in generator mode. Now that there are real world parts and parallel hybrid like the Prius verse series. Can you speak about the efficiency difference between series and parallel hybrid operation?


        We’re tuning our fuel economy right now. From an architectural perspective there are differences between series and parallel hybrids , there’s absolutely no doubt about that. The issue you mentioned the Volt is a series hybrid when we go into charge sustaining mode or when the engine comes on. We like to think of it not as a hybrid. You’ve got to understand that all of the decisions that we’ve made around this product are made because its an EV. That is the first and foremost thing that it needs to be. So because it is an EV some of the decisions that we’ve made around engine operation will be different than what Toyota makes in its parallel hybrid. For them they are always operating in hybrid mode so they need to optimize everything for engine operation.

        In our case we’re optimizing everything for EV operation and the secondary is certainly going to be better than conventional vehicles, but were not necessarily totally optimizing the system for charge sustaining mode because we don’t want to compromise electric vehicle mode.

        --So to be optimally efficient in charge--sustaining mode you might compromise EV performance?

        In the electric vehicle mode, and its not just performance, its efficiency in electric vehicle mode that we’re optimizing.

        --You mean those first 40 miles?

        Right, so you’ve got to remember our principle promise is this is an EV and our engine is there as a range extender and so even when the engine is on, we operate as through we are in EV. All the primary propulsion is satisfied by the electric motor. The engine is really there to supplement power to keep the battery sustained. Now there are a couple of tricks of the trade that we do since we have the engine on more, but for example we don’t want to do a whole lot of gearing that you would do in a parallel hybrid, because none of that is beneficial to you in the EV state.

        --But doesn’t the fact that you could keep the engine at fixed RPMs also allow you better efficiency?

        Actually we don’t keep it at a fixed RPM, we have a window of operation that is optimized. We have been able to optimize the engine for a window of efficiency but it is still best to charge your power and torque levels within that window as the customer torque request varies. We don’t want to always be operating at one state because really you may be putting too much energy into the battery or drawing too much energy out of the battery. It is still good to vary that engine power and torque. Not to follow exactly what the accelerator pedal does, but to optimize efficiency.
        We actually have a ve
        • 3 Months Ago
        Jason, lol, you wish :)
        and how do you think an ICE 'spools up' to begin with..
        it's the electric motor that starts it of course..
        • 3 Months Ago
        Anold, I know plenty of engineering, mechanical and electrical. I can even make the power electronics that drive the motors of electric cars. can you?

        you dodged my questions that would shed light on your error. here they are again. feel free to answer them or go back under the bridge from whence you came.

        do you actually know precisely how the Volt drivetrain is laid out?
        are you aware that GM's Rob Peterson stated 'the Volt has a number of clutches'? care to explain what those are for?
        are you also aware that the chief Volt drivetrain engineer Alex Cattelan has said that the generator motor can be set to drive the car in combination with the primary drivemotor. care to explain that?
        we are not talking about just some guy from Opel
        • 3 Months Ago
        anoldbikeguy, which supplier do you work for? If you really work at MPG (which I doubt you do) just ask someone to see the lever diagram for the Volt transmission. That would end this debate in a hurry. I have seen it.
        • 3 Months Ago
        Joe, NmGfan actually denied the planet gear just above. but you're on a roll, why stop now : )
        you're in such a hurry that you'll state my case and pretend it proves me wrong :)
        • 4 Years Ago
        Nmgfan, I asked him a few question with which he can back up his position.
        you ignore the fact GM's own people talk about Volt operation that would not be there in a series hybrid. it is not just a guy from Opel.
        and my position is not that they will suddenly change the hardware. my position is that it will be capable of battery drive but that the way it's arranged is not the straight forward series hybrid which would not need clutches nor be able to have the generator motor assist the drive motor. these are things we know from GM people. and in retrospect they have never talked about the drivetrain in detail. I always just assumed. I always just trusted them.
        at this point there is no chance we are talking about a misunderstanding. they are deliberately keeping the drivetrain design from us. gotta wonder why.
        Personally I'm very disappointed, not that this drivetrain will really change a lot of things, but why the lies.. why the deception.
        • 4 Years Ago
        I think ABG needs another Poll:

        How many ABG readers think Dan Frederiksen is an idiot?

        That number seems to be climbing faster than projected EV sales in 2020.
        • 3 Months Ago
        correction:

        I think #2 makes the most sense... *stupid finger slip*
        • 3 Months Ago
        So we have 2 sides of the story:

        1) An anti-EV journalist from the Telegraph claiming he has a direct quote from an Opel Engineer... saying there is a direct mechanical connection between the ICE and wheels.

        2) The GM spokesman Rob Peterson saying that the Telegraph journalist took the statement grossly out of context, and re-affirms that there is NO MECHANICAL LINK between the ICE and wheels.

        ***and ABG's Sam Abuelsamid calling the "Opel Engineer" nothing more than an uniformed technician.


        Hmmm... I think #1 makes the most sense.

        Those clutches simply connect the Gen/Motor with the Traction Motor to increase efficiency and performance... Just as Rob Peterson says.

        If anything, the second clutch probably just disconnects the Gen/Motor from the ICE during this mode. So that the ICE is NEVER directly drives the wheels.

        ------

        Any speculation beyond this... would be a gross assumption. And we know what Stephen Seagal thinks of that, don't we Dan?

        • 3 Months Ago
        somebody, do you then know how it works? can you confirm that it can close a mechanical path from ICE to wheels? or better yet tell us how it is laid out
      • 4 Years Ago
      woops, should have read project engineer to shuttle driver,

      (guess I'm trying to give him a promotion, hmmmm?)

      /I'll bet GM would prefer a little tighter information control from those Opel folk, at least until after the IPO.
      • 4 Years Ago
      Dan, so you think there may be an actual change in the Volt/Ampura drivetrain that will be earth-shattering? Like gas-driven wheels? Or words to those effects?
      • 4 Years Ago
      this isn't about overzealous labelling. that's nonsense. labels such as electric car, gas car, hybrid etc have actual meaning! obviously.

      this doesn't clear it up as far as I'm concerned. the POS telegraph article is reprinted everywhere and I'm guessing douche mr english isn't even putting out a clarifying article.

      the original article still stands, no editing, no retraction, the title is "Volt shock" and the first line reads "General Motors announces major change to the Chevrolet Volt and Vauxhall Ampera driveline."
      that doesn't sound like the valet running his mouth. sounds more like GM will not renew leases on EV1 and plans to 'retire' them.

      he goes on: "There are a number of different ways we could do it, but the whole thing is subject to some intellectual property rights negotiations so I can't say any more, said Voight. You will see an announcement this autumn."

      a rather chatty and authoritive valet, wouldn't you say.

      Sam, I think you need to have a few frank words with mr Peterson. either he's ignorant of the situation or he's lying. either way this isn't over.
        • 4 Years Ago
        yes the Paice prius patent. and I think that's exactly what Andreas Voigt was referring to. I'm afraid that the Volt is a prius style drivetrain with a few extra clutches for more options. that it can at any time drive the wheels mechanically from the ICE, simply as a matter of software. the hardware is probably all there already. disgusting
        • 4 Years Ago
        patents could be a real issue.. attach the wheels to the ice and GM may have to pay patent royalties.
        • 4 Years Ago
        GM has already had their 2-Mode Hybrid system. It did not violate any patents by Paice. Very different from Toyota's HSD Power Split system which was simply 2 motors, 1 planetary gear.

        The 2-Mode system had a split input transmission and a split output too. 2 motors, 2 planetary gears, and 5 clutches were required. Very different setup. Not as elegant as the HSD.

        Same parallel hybrid type. Two very different systems. No patent worries.
      • 4 Years Ago
      but that's just it, it now appears the Volt is not a straight forward series hybrid. GM has confirmed it has clutches and planet gear. it's likely a prius type power split device with extra clutches for more flexibility. it appears it could indeed operate like a prius with mere software change as the Opel engineer suggests : )
      it all adds up, his hint that there is an intellectual property issue vis a vis the prius Paice patent. that patent covers two motors, a planet gear and an ICE..

      as a wise man once said in a Steven Seagal movie, assumption is the mother of all fuckups : ) we assumed how the Volt is. and GM deceived us.

      fool me once.. shame on....... George Bush
        • 3 Months Ago
        Dan Fredericksen....

        Are you ready to admit you were wrong?

        You were wrong on 2 things:

        1) The current model Toyota Prius (with its HSD Power Split Device) IS more efficient than the Chevy Volt running in Charge Sustainment Mode

        2) The Chevy Volt will NOT have it's ICE directly and mechanically driving the wheels.

        *** All the proof you need, is right here in this interview of Alex Cattelan, the Chevy Volt’s chief powertrain engineer:

        1) Alex admits that the Volt's CS Mode is less efficient than the Prius... but the Volt was "optimized" for EV Mode.

        2) Alex specifically says, "...decouple the engine or generator from the axle torque requirement.." and explains why that is important. That also explains the need for a few "Clutches".


        We here at ABG await your humble admission of error.



        ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

        http://gm--volt.com/2009/11/23/engineering--design--and--efficiency--of--chevy--volts--generator--mode--builds--on--gms--two--mode--hybrid--technology/

        From Lyle @ GM--Volt.com
        Nov. 23rd 2010

        --I had a discussion with Alex Cattelan, the Chevy Volt’s chief powertrain engineer about the engineering design and operation of the Chevy Volt’s charge sustaining mode. This is the mode that occurs after the car has depleted the first 40 miles of range and the gas generator has begun providing electric power.

        --When you first unveiled the Volt and it was a math model, the car was promoted as getting 50 MPG in generator mode. Now that there are real world parts and parallel hybrid like the Prius verse series. Can you speak about the efficiency difference between series and parallel hybrid operation?


        We’re tuning our fuel economy right now. From an architectural perspective there are differences between series and parallel hybrids , there’s absolutely no doubt about that. The issue you mentioned the Volt is a series hybrid when we go into charge sustaining mode or when the engine comes on. We like to think of it not as a hybrid. You’ve got to understand that all of the decisions that we’ve made around this product are made because its an EV. That is the first and foremost thing that it needs to be. So because it is an EV some of the decisions that we’ve made around engine operation will be different than what Toyota makes in its parallel hybrid. For them they are always operating in hybrid mode so they need to optimize everything for engine operation.

        In our case we’re optimizing everything for EV operation and the secondary is certainly going to be better than conventional vehicles, but were not necessarily totally optimizing the system for charge sustaining mode because we don’t want to compromise electric vehicle mode.

        --So to be optimally efficient in charge--sustaining mode you might compromise EV performance?

        In the electric vehicle mode, and its not just performance, its efficiency in electric vehicle mode that we’re optimizing.

        --You mean those first 40 miles?

        Right, so you’ve got to remember our principle promise is this is an EV and our engine is there as a range extender and so even when the engine is on, we operate as through we are in EV. All the primary propulsion is satisfied by the electric motor. The engine is really there to supplement power to keep the battery sustained. Now there are a couple of tricks of the trade that we do since we have the engine on more, but for example we don’t want to do a whole lot of gearing that you would do in a parallel hybrid, because none of that is beneficial to you in the EV state.

        --But doesn’t the fact that you could keep the engine at fixed RPMs also allow you better efficiency?

        Actually we don’t keep it at a fixed RPM, we have a window of operation that is optimized. We have been able to optimize the engine for a window of efficiency but it is still best to charge your power and torque levels within that window as the customer torque request varies. We don’t want to always be operating at one state because really you may be putting too much energy into the battery or drawing too much energy out of the battery. It is still good to vary that engine power and torque. Not to follow exactly what the accelerator pedal does, but to optimize efficiency.
        We actually have a ve
        • 3 Months Ago
        You sound like someone who just discovered a Bible Code.
      • 4 Years Ago
      Andrew English is an well known anti EV writer , and quite often
      makes un informed statements in his articles for Britains "Telegraph"
      This paper is also promoting climate change denial in the county !
        • 4 Years Ago
        I don't think it is "above" a journalist to completely fabricate a quote. Or take a quote grossly out of context, so much that it becomes equally inaccurate, just like a fabrication.
      • 4 Years Ago
      "Ultimately, this all comes down to people's obsession with labels. If we didn't insist on categorizing everything, it's likely none of this would have ever come up because in the end it only matters if the system works. "

      If by "people", you mean GM marketing, then yes. They're the ones that insisted on calling the Volt an ER-EV instead of just marketing it as a plug-in hybrid. It's easier to say it has a different hybrid system architecture than to say it's a different type of vehicle.
        • 4 Years Ago
        I think calling this type of vehicle a plug-in hybrid is a great idea. Except for the problem that companies already made lots of plug-in hybrids that don't have any usable zero emissions range.

        It's just a case of the most logical term already having been taken to describe something else.

        I think they have to market this car as a different kind of vehicle. When a Prius PHEV is $30K and a Volt is $40K (minus rebate), you need to be pretty clear that there is a major difference between the vehicles or you won't sell any.
        • 4 Years Ago
        @LS2LS7

        Which companies are you referring to when you say that many have "already made lots of plug-in hybrids that don't have any usable zero emissions range"? There hasn't been a single production PHEV released yet. There are aftermarket conversions--are you referring to these? The conversions do have a small AER, but it is "usable".

        In any case, the length of the all-electric range (AER) is immaterial: do only some EVs qualify as such based on their range? The E-REV moniker is a distraction and a source of confusion and is completely unnecessary. The PHEV term is all that is required to describe these vehicles.
        • 4 Years Ago
        @why not the LS2LS7?
        That's exactly the same marketing argument. GM knows if they called it a PHEV then it becomes harder to justify the price tag and it wouldn't be a nice way to counter the backlash from WKTEC.

        As for the range, we already have existing terms to describe it: PHEV10 and PHEV40, for example.
      • 4 Years Ago
      Yeah, and Chevy engineers really do have the cat by the tail. Everything will be all right. I'll have my apple pie ala mode, please. With a hot cup of Seattle's Best roasted coffee. Two sugars and some toasted almond creamer. Ummm.

      Hey, while we're at it, please put on something from Foghat's latest CD, 'Last Train Home.' Loud, rockin' blues done right.

      "Fancy a crisp?"
        • 4 Years Ago
        Huh? Ah, yea, what he said.

        Three articles on this in 36 hours, won't some one please think of the lot boys. My, my what confusion a lot boy can make. That's why GM's PR department gets paid the big bucks!
      • 4 Years Ago

      The Telegraph said:

      ""We are considering driving the wheels directly from the petrol engine," says Andreas Voight, an Opel project engineer.

      "There are a number of different ways we could do it, but the whole thing is subject to some intellectual property rights negotiations so I can't say any more," said Voight. "You will see an announcement this autumn."
      http://www.telegraph.co.uk/motoring/green-motoring/7851482/Volt-shock.html

      Autoblog says:

      "As for the case of Andrew English of the Telegraph in the UK, apparently a technician whose job is to take care of the cars and shuttle them around was the source of the original erroneous story. The technician was not actually familiar with the inner workings of the Voltec system and was not authorized to speak about it. "


      So apparently the Autobloggreen headline should read:

      "Repeat after us: The Chevrolet Volt's gas engine does not drive the wheels! -- But it could, we're not sure what's going to happen or how bad the Volt's performance is at highway speeds. Stay tuned."

      /So, Mr. Voight was downgraded from project manager to shuttle driver, ......hmmmmm?

      • 4 Years Ago
      series hybrids have been used for years with railroad engines and some buses. It's proven technology.
        • 4 Years Ago
        Just because it works well for one industry doesn't mean it will work well for another. Should we start using all steel wheels on cars and run on rails? Of course not, because that would be silly.

        Different powertrains have their own set of advantages and disadvantages for different types of transportation.

        All evidence suggests that a series/parallel setup is best after any AER you have is used up, due to conversion losses present while the engine is providing power to the motor.
      • 4 Years Ago
      WOW, is this topic really that hot? I thought pure electric motivation was the basis for the entire vehicle when they first announced it... and they've been drumming the RE-EV beat ever since. One confused reporter and the whole world goes nuts.
        • 4 Years Ago
        but turns out that there was probably no misunderstanding. turns out the Volt's drivetrain is much different than you might assume from how they described it.
        rather than the battery electric drive and a separate gas powered generator as you might expect, it's likely more like a prius hybrid arrangement with a few extra clutches to give it more operational flexibility. it will still presumably be able to drive as a battery electric but they have been deceiving us.
        it would appear that the german engineer (not the valet they want to pretend he is) Andreas Voigt is right that the Volt/Ampera can actually drive the wheels from the ICE mechanically (prius style) simply by engaging the right clutches. it further appears that GM is afraid to let us know that's how it's designed, hopefully just for stupid PR reasons that they are afraid people wont make a clear enough distinction between the Volt and the Prius then.
        GM's own people have verified details of the drivetrain that confirms it's not the straight forward series hybrid people thought it was. and they wont tell us exactly how it works.
        we should insist
        • 4 Years Ago
        Don't worry Matt. Dan just lives off of confusion and misinformation.

        This has already been debunked by Alex Cattelan, Volt chief drivetrain engineer AND GM spokesman Rob Peterson.

        Yes, the Volt has clutches and gears.... But NO, the ICE will never be mechanically connected to the wheels.

        There are plenty of other configurations that can involve clutches and gears... that are VERY different from the Prius' HSD configuration.

        For instance, the Volt has 2 electric motors. And Alex Cattelan had said in Nov...

        "in EV operation I have two motors on board and I typically use the traction motor only to drive the vehicle. However, I do have some mechanisms to couple those motors and in some points of operation these two motors can be coupled and have a more efficient state."

        "...but what it does is optimize the rotating speed and the losses of the motors so in certain states"

        ------------------

        Dan is just jumping to the same idiotic conclusion that some daft reporter from the Telegraph claims he got from some Opel guy.
        • 4 Years Ago
        Lol, yeah. Thought the same thing. All these articles and it's still the same outcome.
    • Load More Comments