Society Of Automotive Engineers Defines EREV & PHEV




It’s unlikely that the EREV or PHEV battle will ever come to an end, but recently the Society Of Automotive Engineers provided a definition for both classes of vehicles in a paper title “Chevrolet Volt Electric Utilization.

Here are the SAE-provided definitions:

E-REV: “A vehicle that functions as full-performance battery electric vehicle when energy is available from an onboard RESS [rechargeable energy storage system] and having an auxiliary energy supply that is only engaged when the RESS energy is not available.”

PHEV: “A hybrid vehicle with the ability to store and use off-board electrical energy in the RESS.”

So, where does the first-gen Volt fit in? Should the next-gen Volt be classified differently?  BMW i3 REx?  What classification does it get?

Care To Guess Which Vehicles Are PHEV A, B And C?

Care To Guess Which Vehicles Are PHEV A, B And C?

Category: General

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77 responses to "Society Of Automotive Engineers Defines EREV & PHEV"
  1. no comment says:

    i’m not sure how much these definitions will help things, but it is a nice start. for example, ERDTT would presumably exclude the Volt under the EREV definition.

    it seems like the PHEV definition is so broad that it would include just about any hybrid vehicle.

    i would say that PHEV A is the toyota plug-in prius.

    1. David Murray says:

      I had also wondered about ERDTT. Seems like the Volt can’t be full performance battery electric vehicle when the temperature is really cold outside. Here in Texas I’ve only encountered ERDTT maybe 3 times per year, so it hasn’t been a serious issue.

      1. no comment says:

        i think the definitions are fairly easy to fix. for example, if they changed: “an auxiliary energy supply that is only engaged when the RESS energy is not available” to “an auxiliary energy supply is required for vehicle propulsion only when the RESS energy is not available”; that would allow the Volt to fall under the EREV definition even with ERDTT, since ERDTT is not required for vehicle propulsion.

        on second thought, the PHEV definition is probably ok since “off-board” is probably intended to mean external to the vehicle.

        1. lewl says:

          I think the distinction is that auxiliary source is absolutely required vs optional?

          So while ERDTT is “needed by regulation”, it is not actually needed as the car is capable of operating without
          Whereas on a PHEV, it can only provide heat from the auxiliary source, not from the ress.

          A bit of a grey area, so much for making official definitions clear 😉

      2. ModernMarvelFan says:


        It is there to support heating, NOT the vehicle performance requirement.

        No different from engine maintanence or open hood mode…

    2. Bro1999 says:

      A= PiP
      B= Accord Plug-in
      C= Ford Fusion / C-Max Energi

      So basically all EREVs are also PHEV, but not all PHEVs qualify as EREVs.

      1. MrEnergyCzar says:

        I think the Fusion/c-max now have a 19 mile EV range, it might be just a mistake since it changed from 21….

    3. Thomas J. Thias says:

      Mr. Energy Czar is correct. EPA rates the 2015 Ford C-Max Energy PHEV at 0-19 all Electric.

      Meanwhile, opinions below cover a universe of guesstament’s, pondering’s, forceful thought out concept’s and left field hip shots addressing EREV VS PHEV.

      Andrew Farah, Chevy Volt Extended Range Electric Vehicle Chief Engineer was interviewed regarding an internet firestorm that had erupted as word leaked out about First Gen Volt’s 4th driving mode bacl in late 2010.

      Then the Volt’s chief line engineer, Mr Farah fielded deep questioning from then Plug In Cars Dot Coms’ NChambers.

      Listening to Mr. Farahs’ replies and deep engineering answers about the Chevy Volt EREV should render many of the comments that follow below as interesting but baseless.

      This interview took place 2 months before the chevy Volt EREV was initially released, beta, to the general public, in just 6 states and the district of Columbia for the first 8 months of initial production.

      The Andrew Farah Complete Interview, 10.12.2010, on the Voltec Drivetrain.

      Link Goes To Plug In Cars Dot Co – Sound Cloud-


      Thomas J. Thias

      Sundance Chevrolet Inc.



  2. Londo Bell says:

    What you folks are going through, and what SAE has done (dangerously, and imho, wrong!) is to justify a made-up marketing definition into a technical term (one need to know the history on how and WHY EREV came to life, and what the definition came prior).

    Basically, more non-essential and unnecessary standards, and more confusion to the general market.

    I honestly don’t see any of these mess on “regular” ICE vehicles (when they use turbos, superchargers, direct injection, vehicles that require different fuel grade, etc.).

    1. no comment says:

      i don’t think you are correct in your assessment of ICE vehicles. automobile makers (at least used to) make a big deal over turbocharging because it allowed you to get more performance with a smaller displacement engine. such cars were typically denoted with a “T” in the model name that was prominently displayed on the vehicle.

      the significance of these things is for marketing, because marketing messages inform consumer behavior. in the area of electric vehicles, it is important that the public learn the difference between BEV, PHEV and EREV, something most people do not know today.

      1. Lensman says:

        I certainly don’t agree that it’s necessary for the public at large to learn the meaning of “EREV”, a marketing term GM made up for its very well designed PHEV. It’s entirely understandable that GM wants to differentiate the Volt from PHEVs which don’t operate equally well in either electric-powered or gas-powered mode, but inventing a market label that applies to only one model only confuses matters. There are already enough acronyms regarding EVs to confuse even EV enthusiasts (note the arguments over what “NEV” should mean); we certainly don’t need to use the term “EREV” when “Volt” is what we mean.

        1. no comment says:

          you’re making the mistake of assuming that *only* the Chevrolet Volt can be built with a set of attributes associated with an EREV. the reason why you would want a label in marketing is because you want to use it to define a new automobile category. by your reasoning, there would have been no point in introducing the label “CUV” if all they had at the time was a single model that had attributes which fit that label.

          1. Lensman says:

            I’m not sure that “CUV” is that useful a label, either. A very recent video right here on InsidEVs has the Regulatory Officer of Tesla calling the Model X an “SUV”, altho it’s really a CUV.

            Hair-splitting labels are sometimes useful in technical conversations. But I’ve seen nothing to suggest “EREV” is a useful label or category. As more than one comment has noted, the paper referred to in this article is from GM engineers. GM is the company who invented the wholly unnecessary term “EREV”, and so far as I can tell, they’re the only ones who seem to think it’s a useful addition to the ever-increasing list of EV acronyms.

            1. kdawg says:

              I think EREV is a necessary term. It defines how that style of plug-in is different from others. Things like price/range/size/etc. can all be compared among the plug-ins, but one style of plug-in operates in a different manner, that should be recognized.

              Also the Volt is not the only EREV. There is also the BMW i3, the Cadillac ELR, and possible the upcoming Cadillac CT6. I’m sure there will be more in the future.

    2. DonC says:

      Perhaps you can’t understand the distinction because you’re not as smart as the engineers who do?

    3. JakeY says:

      Given there was no link to the paper that has this definition, I had to dig it up:

      It seems it was a paper written by GM, but in no means does this mean SAE endorsed this definition.

      1. ClarksonCote says:

        That’s not true. This story and the others preceding it have been very clear that these definitions are from the SAE.

        1. JakeY says:

          The authors of those articles assumed that just because both definitions were sourced from SAE published papers, that they are both “SAE definitions”.

          As I noted in below responses, if you look at the footnotes of the linked paper, only the PHEV definition is SAE endorsed in the SAE Standard J1715. The EREV definition is sourced from a paper GM wrote in 2008 and published by SAE. So the EREV definition remains a GM definition that SAE did not accept into their terminology.

          1. ClarksonCote says:

            Yes, that appears to be the case, unless SAE definitions have since included EREV now as well.

            That is not clear to me. I believe the author over at Hybrid Cars (Jeff Cobbs) may have access to SAE papers, and may know that SAE does, in fact, define EREV now.

            But you’re correct that, as of the writing of the referenced paper, that does not appear to be the case.

  3. Stephen says:

    Why should we care anyway? The Volt is the Volt. It does what it does. If you don’t like that don’t buy it.

    1. no comment says:

      but if you don’t understand what it is, you probably won’t buy it either. the difference is that the people who don’t understand it aren’t able to develop an informed opinion of whether they like it or not.

      1. Lensman says:

        Inventing acronyms doesn’t help anyone understand something they know nothing about.

        GM marketing could say:

        “The Volt is a car which can run on battery power, which is charged up by plugging it into a wall outlet, or on gas power like a normal car. Unlike other Plug-in Hybrid Electric Vehicles (PHEVs), it performs equally well in either mode.”

        There, that explains it perfectly well. Adding in “The Volt is an EREV, which means…” adds nothing whatsoever to anybody’s understanding. Either way, GM marketing has to explain just why the Volt is superior to other PHEVs.

        1. kdawg says:

          Your description took 45 words, and you referenced other EV acronyms. EREV is just 4 letters. I think you are missing the advantage of EREV over PHEV as well. EREVs are EVs first, hybrids second. PHEVs are hybrids from the get-go. It’s about gas-avoidance and cold engine starts.

  4. Speculawyer says:

    So the E-REV is a subset of the PHEV. Yeah, I can see that.

  5. scottf200 says:

    If you stomp on the accelerator pedal **all** the way to the floor from a stand still up to 70 highway speed…

    If ICE does NOT turn on then EREV

    1. David Murray says:

      Yeah… but many PHEVs can do that if you disable the gasoline engine. For example, in the Ford Energi cars you just put it into “EV-Now” mode and the engine will not come on. Granted, it will get you up to 70 mph that you requested, but it is going to take a while.

      1. Brian Swanson says:

        Realistically they should be called be:

        PHEV-S ( Serial )
        PHEV-P ( Parallel )

        This defines how the electric motor and gas engine interact.

        If you are trying to make a new standard then it should be based on 0-60 times so people can understand if it will be able to merge onto the highway without the gas motor kicking in.

  6. QCO says:

    The definition difference is quite clear and defined by “full performance”, which means rated acceleration and speed without the auxiliary engine. The Volt clearly steps away from the others (including i3 REx) by that definition.

    But let’s face it, this is a political move engineered by GM to further entrench their EREV definition. That in itself is fine from a marketing perspective, but it also shows the SAE is nothing more than an industry political body staffed by pre-retirement hacks rather than innovators setting standards.

    1. JakeY says:

      i3 REx only has less performance after the ESS runs out, so it still matches the definition (which specifies full performance *before* ESS runs out), perhaps even moreso given it has no mode to allow the engine to kick in before the ESS runs out.

      As for SAE being hacks, note that this was just a GM paper that was published by SAE. They published a GM paper on the Volt also in 2008 but no one took that to mean SAE is accepting GM’s definition of EREV. It should be the same case here, even though the article is assuming just because SAE published a paper that it was written and endorsed by them as a whole (not true in 2008, still not true today).

      1. no comment says:

        the i3ReX is always “full performance”, it’s just that what the level of performance is varies depending on the SoC of the battery because the traction motor always turns the wheels exclusively. however, when the low threshold SoC is reached the range extender does “engage” as an alternative energy source to provide charge to the battery.

      2. ClarksonCote says:

        The definitions are from the SAE. All articles on this finding have stayed this clearly.

        Additionally, other sites/authors that are not as lukewarm on the Volt openly share the conclusion from that the Volt have openly shared that the Volt saves far more gasoline over non-EREV PHEVs due to the distinction as defined by SAE.

        For example, “Study Shows Chevy Volt Can Burn Less Gas Than Any Other PHEV” found at

        1. no comment says:

          this article presents the best argument for why you want to create a separate category for the Volt, to make it clear to customers that the Volt is not “just one more plug-in hybrid” and it is not a BEV.

          there are valid quibbles about whether the Volt has enough interior room or whether the visibility is good enough, but in my mind it is the best engineered and most practical (for the general public) *EV on the market.

        2. JakeY says:

          The SAE paper #2015-01-1164 your linked article references does not say that. While the PHEV definition is SAE defined in J1715 rev Oct 2014 (the latest version), the EREV definition is a reference to the same GM-written 2008 document, which indicates SAE did not accept GM’s definition as an official SAE terminology.

          See comment by Jeff Cobb below at who actually bought the paper:

          “A PHEV has been defined by the SAE [6] …”
          “An E-REV has been defined
          [7] as …”
          The definitions are in the article. The footnotes of SAE sources are cited. –
          6. SAE International Information Report, “Hybrid Electric Vehicle
          (HEV) and Electric Vehicle (EV) Terminology,” SAE Standard
          J1715, Rev. Oct. 2014.
          7. Tate, E., Harpster, S., and Savagian, P., “The Electrification of
          the Automobile: From Conventional Hybrid, to Plug-in Hybrids,
          to Extended-Range Electric Vehicles,” SAE Technical Paper
          2008-01-0458, 2008, doi:10.4271/2008-01-0458.

          1. ClarksonCote says:

            Hi JakeY, yes you may be correct, I apologize. The other articles also concluded EREV was defined by SAE, when at least the paper only proposes a definition.

            Although, what’s not clear is whether or not SAE has since adopted such a definition. They may have, I personally don’t have access to their terminology/information reports on EVs.

        3. Lensman says:


          “…the Volt saves far more gasoline over non-EREV PHEVs due to the distinction as defined by SAE.”

          You’re confusing the name of a thing with the actual thing. The superiority of the Volt’s performance as a PHEV is due to the GM’s superior engineering, not due to a label some marketing group gave to the Volt.

          * * * * *

          “The name of the song is called ‘Haddocks’ Eyes.’”

          “Oh, that’s the name of the song, is it?” Alice said, trying to feel interested.

          “No, you don’t understand,” the [White] Knight said, looking a little vexed. “That’s what the name is called. The name really is ‘The Aged Aged Man.’”

          “Then I ought to have said ‘That’s what the song is called’?” Alice corrected herself.

          “No, you oughtn’t: that’s quite another thing! The song is called ‘Ways And Means’: but that’s only what it’s called, you know!”

          “Well, what is the song, then?” said Alice, who was by this time completely bewildered.

          “I was coming to that,” the Knight said. “The song really is ‘A-sitting On A Gate’: and the tune’s my own invention.”

          Through the Looking Glass and What Alice Found There by Lewis Carroll

          1. no comment says:

            no, there is no confusion. labels are for marketing purposes; to make it easier for consumers to make purchasing decisions. the reason being that most people are not interested in reading white papers that detail the operation of one vehicle versus another. what most consumers are interested in are consumer attributes and how a given product meets those attributes.

            1. ClarksonCote says:

              Lensman, I’d have to agree with no comment here. One critical aspect of the Volt’s great engineering is that it can be propelled at any speed or acceleration with full performance by the electric motors.

              That is a defining characteristic that makes plug-ins very much like an EV until they need additional range, and one that merits a distinction.

              While I agree it may be confusing for people today, once people understand the difference and plug-ins are gaining marketshare, people will know what an EREV is, and they will prefer one to a general PHEV.

  7. GSP says:

    I am not sure these definitions have been formally accepted by SAE as official SAE definitions.

    They are used in a paper written by GM engineers, and the SAE did publish the paper, but that is different from officially endorsing all of its content.

    Ironically, the Chevy Volt does not even qualify as an EREV per this definition since the driver can engage “hold mode” at any time, not “only when RESS energy is not available.”

    I think more work is needed before the SAE would adopt this definition.


    1. JakeY says:

      Yep, just like the paper that was written in an SAE publication back when the Volt was being developed in 2008, this is just a paper written by GM and published by SAE. In no means does this mean SAE accepted this definition, just as it didn’t mean that back then.

      2008 paper:

      2015 paper which this article references:

      1. Breezy says:

        The SAE Standard J1715 was updated in October 2014.

        If somebody wants to pay $75 to look at the standard, or if they have access through work, we can verify whether the SAE actually adopted the EREV term, or not.

        1. JakeY says:

          No need. Jeff Cobb at actually bought the paper #2015-01-1164 this article refers to.

          In the footnotes it says the PHEV definition is from SAE Standard J1715, Rev. Oct. 2014 as you mention.

          However, the EREV definition is from the same 2008 GM paper I linked above. SAE Technical Paper
          2008-01-0458, 2008, doi:10.4271/2008-01-0458.

          So it’s pretty clear the EREV term still remains a non-SAE term. It’s just the reporters assume because both terms were sourced from SAE publications that both were SAE endorsed (they didn’t look closely and see the EREV definition is sourced from a GM paper that was published by SAE).

          1. Breezy says:

            I agree with you. In fact, I commented as such to the original story at, hoping somebody would correct it before the error propagated across the Internet.

            It seems logical that this GM paper would have referenced SAE J1712 if that standard included the EREV definition, not just an earlier GM paper.

            I think EREV is a perfectly valid and useful term in engineering publications – but it’s not an SAE term.

            1. JakeY says:

              I didn’t realize you actually commented there and now that I look closely Jeff Cobb was the author of the article and he didn’t realize that the second source was a GM paper (only that it was published by SAE). Unfortunately, it seems this mistaken assumption has already propagated through the web.

              As an engineering term, perhaps EREV is useful. But as other people put it, the definition given might even exclude the Volt unless some exceptions are made (ERDTT and hold mode). The i3 REx seems to be the only car that fits that straight definition with no exceptions. It still needs a bit of refining to fit the Volt.

              1. no comment says:

                hold mode is within the EREV definition and the EREV definition can be easily modified to include ERDTT.

              2. ModernMarvelFan says:

                “ERDTT and hold mode”

                Neither is default mode and none of them contradict the “performance” requirement mode.

                ERDTT is for climate control reason, NOT performance of the vehicle. Hold Mode is none-default mode which is similar to engine maintanence mode and open hood service mode.

    2. no comment says:

      “hold mode” and “mountain mode” don’t exclude the Volt from the EREV definition because what these modes do is charge the set point at which the RESS is no longer available; mountain mode changes the set point to twice the normal set point SoC, and hold mode changes the set point to the current SoC. nothing in the EREV definition defines a set point SoC at which “the RESS is RESS energy is not available”.

  8. Mikael says:

    I wonder why they even bother. Why not just be happy that the Volt has the best PHEV drivetrain out there and not try to confuse people with a label that most likely isn’t even applicable to the Volt.

    1. no comment says:

      this is about marketing; you need to have an easy way to get the consumer to differentiate your product from other products. so you establish the label, train people to the label, and then consumers make decisions based on the label.

      i agree with this approach, it is important that GM differentiate the Volt from BEVs like the Leaf, and from PHEVs like the plug-in Prius.

      1. Lou Grinzo says:

        No, it’s not important that GM make such distinctions. A mainstream (i.e. not us) consumer cares about how much the car costs (both up front and ongoing) and what you get for that expense. That what you get is measured in things like appearance, color, seat comfort, performance, handling, etc. Very, and I mean VERY, few people today truly care about “what’s under the hood” unless that maps directly to something like how often they have to plug it in or how well it accelerates.

        1. no comment says:

          believe it or not, people actually do like to feel that they know what they’re buying. but people don’t want long winded technical descriptions. what labels do is provide a simple heuristic that allows people to take a potentially dizzying array of product choices and drop them into well defined bins. there are a set of attributes of EREVs that are not attributes of PHEVs or BEVs. in the marketing game, you want the attributes to be things that are of importance to consumers. then when you tell them that a car is an EREV, they will associate those attributes with the car and will want to buy that car over cars that are associated with PHEV or BEV labels.

    2. kdawg says:

      “a label that most likely isn’t even applicable to the Volt.”
      How can the label not be applicable to the Volt when it was created to literally define the Volt’s drive train?

  9. Dan says:

    One question: Does the mass market care?

  10. Lensman says:

    I’m not an expert in this particular narrow subject by any means, but so far as I know, the only PHEVs which won’t engage the gas motor under any condition, until the battery pack is mostly drained, are the Volt and the REx optioned BMW i3. My understanding is that most PHEVs will engage the gas motor when necessary to provide a boost of power under strong acceleration or when climbing a steep hill, even when the battery pack is well charged.

    In other words: According to the definitions in the article above, so far as I know, the Volt and the BMW i3 REx are the only PHEVs that fit the EREV category. Since GM made up the “EREV” label specifically for the Volt, I frankly don’t see the value of trying to use it for anything else. The base i3 isn’t a PHEV, it’s a BEV, and the gas generator very definitely is an add-on. Unlike the Volt, the i3 wasn’t designed to operate just as well in either mode; the REx just gives a limp-along gas powered mode intended to get you to a charging station. Therefore, technically the i3 REx does fit the “EREV” definition, but it’s quite misleading to lump it into the same category with the Volt, suggesting they perform in a similar manner.

    I guess there is some value in making it clear that EREV is a subset of PHEV, but other than that, I don’t see any value of discussing EREVs as a separate category.

    There is a spectrum in PHEVs, with the Prius plug-in on one end, and the BMW i3 REx on the other end. The Prius has a very short electric-only range and is primarily powered by gas; the i3 REx is exactly the opposite.

    Separating out one narrow part of the PHEV spectrum and giving it a separate label doesn’t appear to me to have much value. It would be a much better service to everyone interested in EVs to give a thorough definition of the PHEV category as a whole, and explain how much PHEVs vary from one end of the spectrum to the other.

    1. Ambulator says:

      I think the Fisker Karma would also qualify as EREV, at least if they ever start making them again. Fisker called their cars REEV, though.

    2. Spider-Dan says:

      Both the Karma and the ELR qualify as EREV.

  11. Sounds like a Fuel Cell EV also fits into the E-REV definition? … re: RESS. As SAE just defines onboard ‘rechargeable energy storage’, without specifying inly energy from the onboard storage battery. Also nothing about an E-REV recharging its energy storage by plugging into a electrical outlet. Just saying …

    (from the article, SAE’s definition)
    E-REV: “A vehicle that functions as full-performance battery electric vehicle when energy is available from an onboard RESS [rechargeable energy storage system] and having an auxiliary energy supply that is only engaged when the RESS energy is not available.”

    1. no comment says:

      for FCEV; what is the auxiliary energy source? if there is none, then FCEV does not fit the definition of EREV.

      good point on the EREV definition not requiring storage of energy from an off-board energy source. that said, i don’t know that you would operate a hybrid (which stores energy from on-board regenerative braking) in a way that meets the EREV definition since the typical hybrid uses the electric motor to get the vehicle off the line and to a (typically relatively low) speed where the gasoline motor takes over.

  12. Bill Howland says:

    Man, this website keeps locking up my computer.

    I guess itsbetter to have SAE make up meaningless acronyms then have them actually try to make anything like that horrid J1772 standard.

    1. JakeY says:

      Not sure if anyone has the same, but on the right side there is a very annoying anti-vaping/e-cigarette video ad that keeps popping my window up to it. I must wait for it to finish playing before I can comment or read comments (otherwise it keeps trying to drag my window back up). And it occasionally replays.

      1. Jay Cole says:

        Hey JakeY, Bill,

        There should be zero pop-ups anywhere – it is 100% unintentional, we have not allowed any advertisers (ever) to serve intrusive ads, as it interferes with the readability/enjoyment of the site…but sometimes things slip through the filters.

        We’ll send a note to the provider right away to boot the placement (and any/all pop-ups) from the site. Apologies for that.

        1. Bill Howland says:

          Yeah Jay, its getting really bad around here. The processor load from your website won’t let me type at veven 1/3 my nrmlspeed without losing chars.

          A few months ago, Icould open 4 windows at a time no problem, and now 1 window only is almost impossble. I use crapcleaner and malwarebytes all time.

          Some ads refuse to let you scroll down.

          There are way toomany ads here. It was much better on the old software.

          1. Jay Cole says:

            There should be no scroll ads at all.

            I’m pretty sure it is one or two specific ads that are targeted to something to your location/interests specifically. These ads have somehow made it by the filter unbeknownst to the provider.

            On our end (and for almost everyone), there is no visible pop/scroll ad. Not sure I can get a hold of IT people this late at night (12:35 AM ET), but hopefully we will have it straightened out by the AM.

          2. ClarksonCote says:

            Jay, FWIW, this happens on my iPad air now too, typing very delayed. Though I’ve attributed it more to Apple than the site specifically, maybe there’s more to it than I suspected?

        2. JakeY says:

          Hi Jay,

          Thank you for addressing this. To be clear, it’s not a popup ad (I have never seen popups here), but what it does is forces my window up to the height of the video. For example if I scroll down to comment and that video ad shows up, my window automatically goes back to the top to where the video is visible and sticks there until the video is done playing. There is probably some sort of javascript embedded in that ad to do that.

          It only occurs with that specific video ad, other video/picture ads don’t have that issue. Luckily it only occasionally shows that ad, so you are probably right that it may be targeted (although I’m not sure why it would show to me given I don’t browse any smoking/vaping related sites).

          1. Jay Cole says:

            Hey again,

            No problem, we want to get it figured out. Out ad provider said that indeed something did accidently get by in relation to what you experienced and it has been rectified.

            However, as this is was a very select issue (apparently a dozen or so ad placements over tens of thousands of views), I can’t verify myself.

            If you do see this video ad (or anything else) affecting your ability to navigate the screen/outside of a normally displaying ad, please do mention it, or better yet shoot us an email:


        3. no comment says:

          why is it that the “ad choices” pop-ups have absolutely nothing to do with the highlighted text? if i see the highlighted text “electric vehicle” i would expect to see information related to electric vehicles and not a celebrity photo.

    2. Lensman says:

      I’m having that problem too. I’m still using Windows XP, and I can’t update something… Java or Flash?… to the newest version. I’ve been assuming that’s the problem here.

      Are you also running Windows XP?

  13. Jeff N says:

    As others have pointed out, this paper’s definition of EREV is just referencing the more complete definition in an earlier 2008 SAE paper written by GM engineers. As far as I know, EREV has not been adopted by the SAE itself through its committee process and the name and it’s definition are not officially defined by the SAE.

    GM’s 2008 definition can be reduced down to 3 criteria:

    1. No range extender starting due to driver torque demand
    2. No range extender starting due to vehicle speed.
    3. Vehicle must fit the “Full-Performance” EV class criteria defined in a CARB report when the vehicle runs on battery power alone

    That’s it. There are lots of other words in the paper but when taken in their full context that is all that their definition requires.

  14. Jeff N says:

    The key paragraph in the original 2008 paper says:

    “The operation of an E-REV looks similar to that of an Initial EV PHEV; however an E-REV must maintain this mode of operation on all operating schedules when energy is available from the battery. An E-REV does not need to start the engine for speed or power demands from the driver and therefore does not need to transition to a Blended operation strategy when battery energy is available, unlike the Initial EV PHEV.”

    This EREV definition (or E-REV as it calls it) is all about how a vehicle operates and stays in EV operation. These are requirements on the propulsion behavior of the vehicle. There is no stated requirement in the 2008 paper with regards to cabin heating, maintenance modes, or the propulsion behavior after the range extender has started (series vs parallel).

    Under this definition, the first and second generation Volt, the Cadillac ELR, and the BMW i3 with range extender are clearly EREVs. The Ford Energi Plugin’s could also be considered EREVs when the EVNow button is pressed (which is persistent across vehicle restarts). Future Plugin’s with larger battery packs and range extenders will also likely fit the EREV definition since blended battery plus range extender behavior is typically required due to the lower power output capabilities of smaller battery packs. The Cadillac CT6 plugin hybrid is not an EREV even though it uses the 2016 Volt’s 18.4 kWh battery pack which can output upwards of 120 kW because Cadillac wanted to always make a full 335 HP available to the driver.

  15. Bone says:

    Electric range and performance in electric mode is what matters to consumer. GM and other manufacturers should be able to communicate this information to public without making up more acronyms.

    This definition of EREV and PHEV doesn’t help to underline why Volt is better than other PHEVs. Within these definitions it is perfectly possible to make an EREV with 10 miles electric range and a PHEV with 100 miles electric range.

    1. Jeff N says:

      Whether a vehicle uses a blended PHEV strategy or a EV-only first EREV strategy is independent of EV range which is exactly why EREV needs to be its own characteristic and acronym. Just calling something a PHEV-10 vs a PHEV-40 does not imply whether the engine will start burning gas if you accelerate rapidly. Obfuscating or hiding a vehicle’s powertrain strategy does a disservice to customers.

  16. ClarksonCote says:

    Table 2 in this article (and the SAE paper, I presume) is a great way to technically summarize the benefits of a PHEV that is an EREV over a general PHEV.

    Or, more to the point here, it shows how the Volt excels in being an EV first and foremost over other vehicles with a plug. 🙂

    1. Brian says:

      I think you mean “with both a plug and a combustion engine”

      1. ClarksonCote says:

        Well, yes, it’s hard for an EV without a gas engine to never not be an EV; I assumed that point was obvious. 😉

  17. Bill Howland says:

    It will be interesting to see exactly how the CT-6 ‘option’ on the large cadillac will be implemented. I believe this vehicle will be 2 feet longer than an Impala. My ELR is 9″ longer, and 3 ” wider than a volt, but somehow it feels much bigger, even though its not as practical as the hatchback volt.

    They called the ‘concept’ GM’s first PHEV, and I assume it will be at least as efficient as the VOLT and ELR are now, since there is nothing stopping them from directly driving the wheels. That’s why I think all these arbitrary definitions are a waste of time, especially since the SAE couldn’t even get a ‘one-quadrant’ car plug right.

    The only thing I’ll say for the J1772 is that it is somewhat ubiquitous. And if you stay away from certain car manufacturers and certain EVSE manufacturers, you’ll do fine and have a trouble-free existence.

  18. Bill Howland says:

    My claim, as well as half the others here, say that additional meaningless acronyms are a waste of time.

    GM took 18 months to stop lying about the operation of the car period and only stopped when caught red-handed by a NYS Dept of Mtr Vehicles employee. They only told the truth to MotorTrend and Forbes. Dealers were kept in the dark, including mine.

    Now even this definition of ‘full performance’ is dopey. My ELR Cadillac lists as an ELR. But, If I want ‘full performance’, I have to manually start the engine, since it has substantially more power with the engine than without. So that’s a PHEV unenhanced right? Not according to GM. Their first PHEV will be the CT-6, unless of course, they change their minds about what their cars are. Its that silly.

    The SAE can’t get a silly 110 or 220 single phase unidirectional (only a load) plugin standard to be consistent between EVSE (another joke) and vehicle, can we agree that a plug in cord is kinda necessary for an electric vehicle?

    So then they are wasting time on this silliness where they will be forced to redefine their HARD definitions if and when the ELR comes out..

    What? Oh… Yeah, there’s one in my garage already.

    1. Bill Howland says:

      er… Extended Range Electric Vehicle. I have no idea what a silly ELR is. Electrifiederd Caddy probly.