Shifting a Chevrolet Volt Into Reverse at High Speed (video)


EV Driving

The Volt’s Firmware may be as Innovative as its Voltec Transmission (shown here)

Well, relatively speaking anyway.

In this video, the 2013 Chevrolet Volt is being shifted to reverse at speeds as high as 25 mph. The person driving the Volt (me) is testing some functionality that was confirmed by Volt advisors and by other enthusiasts online well over a year ago.  The video shows that the programmers of the Volt’s firmware for propulsion algorithms even accounted for non-standard and unexpected driving events, with a great deal of sophistication and well-executed behavior.

When shifting to reverse at speeds up to 35 mph, the Volt simply uses its regenerative braking to slow the vehicle until it stops.  Pressing down the accelerator increases the regeneration slightly.  Once the regeneration brings the vehicle to a stop, the firmware seamlessly begins to propel the vehicle in reverse.  The result is one fluid motion from forward to reverse.

While we don’t recommend you try this at home, it’s an interesting example of the level of rigor that was performed in designing all of the Volt’s propulsion algorithms.

Category: Chevrolet

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33 responses to "Shifting a Chevrolet Volt Into Reverse at High Speed (video)"
  1. David Murray says:

    I didn’t realize the bar changed from yellow to green. I’m partially color-blind and have a hard time telling bright green from yellow.

    1. Will says:

      They’re two separate bars so you should still be able to tell the difference.

  2. ModernMarvelFan says:

    Neat feature. Does it apply to 2011/2012 models as well?

    How about the new Gen 2.0 Volt? Will it do the same with different configuration?

    1. Eric Cote says:

      Yes, this works with the 2011-2015 Volts. I suspect the same behavior will be present in the Gen 2, since this functionality just uses regenerative braking, but I don’t know for certain, 🙂

  3. EVer says:

    Volt should not be software limited and all should have the standard 0-60 in the 5 second range

    1. Jouni Valkonen says:

      If that was the case, then who would buy gasoline cars anymore?

  4. James says:

    Thanks Eric. Nice how it’s programming makes the transition so smooth.

    Now I know what to do next time I’m in a police chase situation. 🙂

  5. jdbob says:

    Shouldn’t that be expected behavior for any computer controlled powertrain, at least for a PHEV? What do other cars do?

    1. Eric Cote says:

      I know that the Leaf, rather than implementing something like this, simply won’t allow you to go into reverse while you are above a couple MPH in drive.

      Not sure about other PHEVs and EVs

      1. Mike says:

        To be more specific, if you try to go into reverse at a higher speed than about 7 mph then it will put the car into neutral, which can be a useful feature at times when you want to coast with no regen without having to feather the accelerator.

  6. Brian says:

    So if you hit the brakes while travelling forward at 25mph in reverse…does the car accelerate?

    1. Foo says:

      Yes, the relative rate of reverse momentum will increase when you press the brakes.

      1. Brian says:

        Touche. Given that acceleration is defined as a change in velocity, of course the car will accelerate.

        In the vernacular sense, though – will it start accelerating forward? I mean, the “go” pedal’s function has been reversed, so why not the “stop” pedal? 😉

  7. Bill Howland says:

    Yeah, I don’t understand ‘the car is smart enough’ comment.

    At the steel plant I worked at around 37 years ago, at the time they had ‘modernized the main 4000 hp mill’, but all the ancillary ‘drives’ were yet to be ‘modernized’. I put that in quotes since all the money they spent didn’t improve efficiency one iota, although by ‘converting to electronics’ they sure put a lot of extra harmonics onto the serving power line that had to be ameliorated elsewhere in the plant… Anywey, there were

    (2) – 200 hp DC screw downs
    (8) – 50 hp dc roller conveyers.

    All shunt wound motors. 10 ‘drives’ total.

    All controls were synchronized to an operator handle only controlling milliamperes.

    I liked the watching the voltmeter and ammeter on each of the ‘drives’. If the operator went full reverse to full forward (something he did thousands of times a day and vice-versa since this was a blooming mill after all), the center 0 ammeter would go from a low forward current to -600 amps, and the voltmeter would slowly go from plus 250 volts, through 0, and back to minus 250, basically approximating what was happening to the meter speed wise. Current limit was obviously set at 600 amps.

    Basically did what the volt just did here, except at least as smoothly. I notice my ELR has mushy response to emphasize the boatesqueness of the response on the paddles.

    What was used here? Westinghouse ROTOTROLS.

    The main motor was a 750 hp 2300 volt synchronous 25 hz 750 rpm (4 – pole) motor, each running 5 generators on each end of the shafts.

    The ‘drives’ (ROTOTROLS) were run by 5 double shafted 3 hp induction motors, (2 pole, 1425 rpm) each providing the motive power for two rototrols.

    There was a ‘pattern field’ adjustment that made these specialty generators into operational amplifiers in that THAT pattern field overcame the losses in itself).

    They had a billing meter installed on the feed for the 750 hp motor, and it was fun to watch the screwdowns and conveyers go from full forward to full reverse, because at the moment of the switch, the billing meter would start spinning backwards almost as fast as it had been spinning forwards. with now all the conveyor motors being generators, the motor generator set becoming a generator-motor set, and power being sent back into the 25 hz mains.

    So just think of that: Op Amps with magnetics, but no electronics.

    These rototrol systems were obviously easily parallelled so that a single control could make 10 drives behave alike, and they were so trouble free once ‘alligned’ that they just worked. Anyone who has rode in an old variable speed Westinghouse Elevator has probably been under ROTOTROL control.

    1. Eric Cote says:

      “Yeah, I don’t understand ‘the car is smart enough’ comment”

      Hi Bill, all I mean is that the programming was made to deliberately allow this feature, whereas other EVs seem to just not allow reverse when driving forward. My sample size is low though (Volt and Leaf) so I’m not certain what is the norm here with other electric vehicles.

      1. Bill Howland says:

        Yeah, thh rodster woldn’ alow i eitr. Mn wh is wrong wh thi websie

  8. Jouni Valkonen says:

    is it not the point of regen braking that motor is turned to reverse mode when braking regeratively?

    1. Lensman says:

      It depends on what you mean by “reverse”. In an EV under electric drive, the direction of rotation of the rotor in the electric motor is only reversed when backing up, not when doing regenerative braking. The latter is accomplished by reversing the direction of rotation of the magnetic fields… a rotation which then runs in the opposite direction from the way the rotor is rotating.

  9. Robert says:

    An old mate of mine tried something similar back in the 90s with his old Mini. His aim was to leave longer black lines when he wheelspinned away.
    He rolled backwards down a hill to about twenty miles an hour and then floored it in first gear. He got to regenerate his gearbox. Had to, because some of the internals were left amongst the oil slick on the road…

  10. arne-nl says:

    The Prius does the same thing, although I only tried for speeds up to ~15 km/h.

  11. Martin T says:

    GM built a lot of smarts into the car they never got real credit for.
    Good design electric motor control always impresses.

  12. Forever green says:

    This is probably the best car General Motors has made in a long time and they are not getting enough credit for it because they have a reputation for making cars with problems. I think eventually they will get credit for the Volt, but they have an image problem to overcome.

    1. Dave K. says:

      In a long time? how about ever! I’m amazed they pulled it off and you are right, they don’t get enough credit, probably because so many of us remember that stack of crushed EV-1s.

      1. ClarksonCote says:

        Yeah, it’s unfair to remember only the crushed EV-1 though… Honda, Ford, and Toyota also had all their EV’s crushed, with the exception of very few that were saved.

        1. Jeff Songster says:

          Ok… remember the corporate evil of all three companies. Honda is on my list already for crushing the EV Plus… and building 60k Miles planned obsolescence into their Odyssey transmissions. I won’t be darkening their door ever again.
          GM gets dinged for the EV1 and letting Saturn dealers fall back to the dark side after a promising Tesla-esque start… (one price, our dealers are better) and for harassing me endlessly before finally buying back my GEO Metro in arbitration for a stalling problem caused by an absurdly low idle that got them the 50+ MPG.
          As for Toyota less vitriol… until recently. They get credit for their Original NiMH Rav4EVs… many of which are still roadworthy… and for RAV4EV via Tesla…( awesome car virtually unsupported by the grand Yota… left out the CHAdeMO too… but Tony Williams is fixing that omission) Big Toyota ding for the idiotic Hydrogen time wasting Mirai… where they have absurd, propagandist, marketing… and hand built nearly useless, ridiculously expensive, infrastructure lacking, cars… but hey at least they didn’t forget the CHAdeMO… just the bigger battery.
          So… yeah… GM won’t get credit for building a better hybrid than Toyota until they actually make more rational choices and LEAD the markets … no more compliance cars… advertise your electrics… build out the infrastructure… CCS??? Come on!

          1. ClarksonCote says:

            “GM won’t get credit for building a better hybrid than Toyota until they actually make more rational choices and LEAD the markets”

            Well, last I knew, GM is continuing with the Volt and ELR, has the Spark EV still available, introduced the Cadillac CT6 PHEV, and also the Bolt.

            Meanwhile, Toyota has… the PiP and the Mirai fuel cell?

            It’s clear to me that GM is not all about compliance. If they were, they wouldn’t have done a Volt, especially nationwide, since it doesn’t get them any ZEV credits.

            So while Toyota did a “one and done” on the Rav4 EV and show little to no interest in PHEVs, GM is moving forward in more ways than one.

            As for advertising, you may want to check out an alternative perspective on why it’s been the way it has:

            We’ll know soon if that’s the case.

    2. Lensman says:

      I’m embarrassed to admit that I did some bashing of the GM Volt in the period when it was new… not on InsidEVs, though, it was years ago. Bashing because GM deliberately mislead the public, first describing the Volt as a pure serial PHEV, then later claiming that there was no direct connection between the gas motor and the drivetrain. Both claims were untrue.

      But the inexplicable an bizarre dishonesty of GM’s marketing department shouldn’t detract from the brilliant engineering GM achieved in making a PHEV that performs equally well in both EV and ICEV driving modes. It also deserves credit for making a fully functional, highway-capable PHEV with the highest percentage of electric-powered miles as compared to gas-powered miles; a record which (so far as I know) it still holds, 4 & 1/2 years after the Volt debuted!

      1. ModernMarvelFan says:

        “first describing the Volt as a pure serial PHEV, then later claiming that there was no direct connection between the gas motor and the drivetrain. Both claims were untrue.”

        I am sorry to do it, but I am going to have to set you straight again.

        What is the differece between pure seril PHEV and lack of direct connection between the gas engine and drivetrain? Aren’t they the same thing instead of 2 different thing as you claims?

        Also, techically speaking, there is no “direct” connection in the traditional mechanical sense as in single and only connection. The electric motors has to spin before any engine torque gets to the wheel..

        Please study how transmisions work before you comment about it again… Study a 8-speed transmission while you are at it…

        1. Lensman says:

          ModernMarvelFan asked:

          “What is the differece between pure seril PHEV and lack of direct connection between the gas engine and drivetrain? Aren’t they the same thing instead of 2 different thing as you claims?”

          Well, when you put it like that, yes that’s just two different ways of saying the same thing.

          But that’s not how it happened. First GM said the Volt was a pure serial EV. Then later they admitted this wasn’t true, lamely making some excuse like they wanted their Voltec patents to be approved before they explained how it really works. (This is B.S., as patent protection applies from when you file, not from when the patent is approved.)

          But after GM admitted the Volt isn’t a pure serial hybrid they then claimed there was no direct mechanical connection between the gas motor and the drivetrain. So whether you call that a different lie or just another way of saying the same lie, it’s still two lies about the Volt from the GM marketing department.

          ModernMarvelFan asked:

          “Also, techically speaking, there is no ‘direct’ connection in the traditional mechanical sense as in single and only connection. The electric motors has to spin before any engine torque gets to the wheel..”

          Your attempt here at trying to confuse the meaning of the phrase “direct connection” reminds me of a quote from “Lawrence of Arabia”:

          “If we’ve been telling lies, you’ve been telling half-lies. A man who tells lies, like me, merely hides the truth. But a man who tells half-lies has forgotten where he put it.”

          1. ClarksonCote says:

            If it were truly a “direct link” it would never be able to operate as a serial PHEV, which it does the majority of the time.

            Rather, the mechanical link through the motor as a carrier is done only for efficiency improvement when there is low power demand, not because it is a limitation or because it needs to.

            I would liken this to a V8 with cylinder deactivation. It deactivates the cylinders for efficiency only, which is optional and not a requirement for operation. This doesn’t make it any less a V8, and in my mind, the mechanical link engaged for efficiency only does not make the Volt any less a series hybrid. I’d argue it is better than a series hybrid, and would call it.., an EREV. 😉

            See also

            1. James says:

              So what would you describe the Ford Energi system where either/or/and gas/electric drive the car?

  13. jdbob says:

    Just for fun I tried this on my C-Max Energi. I shifted from Drive to Reverse at about 25mph. At the point the car appeared to just coast, like it was Neutral, until it got down to about 15mph and then it started slowing down and started moving in reverse.

    I guess each manufacturer just picks a speed, possibly using a dartboard, where it will start applying reverse torque.

    1. Eric Cote says:

      Thanks for sharing! It seems most EV manufacturers don’t allow reverse at all when driving forward (Tesla and Nissan, for example). It is cool to see the C-Max behaves similarly to the Volt!

      I suspect the lower speed before behaving the same way as the Volt is related to the battery size and/or electric motor size, since both are smaller in the C-Max and may not be able to handle as much regenerative slowing. Only a guess though, it could also be arbitrary as you suggest.