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

JUN 9 2015 BY CLARKSON COTE 33

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.

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33 Comments on "Shifting a Chevrolet Volt Into Reverse at High Speed (video)"

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David Murray

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.

Will

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

ModernMarvelFan

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?

EVer

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

Jouni Valkonen

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

James

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. 🙂

jdbob

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

Brian

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

Foo

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

Brian

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? 😉

Bill Howland
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… Read more »
Jouni Valkonen

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

Lensman

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.

Robert

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…

arne-nl

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

Martin Tesar

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

Forever green

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.

Dave K.

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.

Lensman

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!

ModernMarvelFan

“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…

Lensman
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… Read more »
jdbob

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.