GM details Chevy Bolt's 'one-pedal driving' modes

General Motors has outlined the customizable 'one-pedal driving' modes that will help Chevrolet Bolt owners maximize vehicle range.

Four operation modes provide varying levels of electricity regeneration, in some cases eliminating the need to press the brake pedal to stop the vehicle.

Operating in 'Drive' and easing off the accelerator is the closest to a traditional driving style, but offers the lowest amount of regeneration. Using the 'Regen on Demand' paddle on the back of the steering wheel can help bring the car to a stop without wasting energy for the friction brakes.

Drivers can also choose to drive in 'Low,' with our without the Regen on Demand paddle, for the highest level of electricity regeneration.

GM suggests the Bolt's range can be improved by up to five percent if drivers do not need to use the brake pedal.

"Bolt EV customers who want an engaging driving experience will love the thrill of one-pedal driving," said Bolt chief engineer Josh Tavel. "They will be able to tailor the vehicle to their preferred driving style and maximize their range."

The company has not yet announced a specific EPA range estimate for the Bolt, instead reaffirming a vague promise for 200 miles or more. Additional details will presumably be announced closer to the Bolt's arrival later this year.

Read more: http://www.leftlanenews.com/gm-details-chevy-bolts-one-pedal-driving-modes-92751.html#ixzz4JavBKK8m

I love that they are making this adjustable. The one thing that I wish they would add is the ability to coast with your foot off both pedals. Typically I would want either that, or full regen (with no creep - the car should come to a complete stop). Everything in between feels like a concession to make the ICE drivers more comfortable, which is fine. Even as a default, that's fine. But I want my EV to drive like only an EV can.

I don't know why they think one-pedal driving is more efficient. Its not like the brake pedal uses the brakes. The brake pedal initiates regen. Actual friction brakes aren't used unless you press harder than the regen can handle.

My Spark EV has a D and L mode. In L mode taking your foot off the gas immediately starts regen braking. Its great for going down hills, but I think it is actually less efficient because there is very little "gliding" where the car is just rolling. Instead there is always a little thrust or a little regen. Since these are not 100% efficient systems it is energy loss compared to gliding.

--Bob

rbroders said:

I don't know why they think one-pedal driving is more efficient. Its not like the brake pedal uses the brakes. The brake pedal initiates regen. Actual friction brakes aren't used unless you press harder than the regen can handle.

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I dunno - this press release has me concerned. After earlier confusion about whether or not the Bolt supported "blended braking" I note that of the four "regen levels" mentioned in the press release none of them involve the brake pedal. Is it possible that means that you won't get any regen from using the brake pedal alone? I hope not - I hope it's just poor wording on the part of the marketing department...

'Customizable' that's the sweet word!

Being new to EV's I don't know that much non generic information about them. I never knew the details of the information above. A great read for me thx

rbroders said:

I don't know why they think one-pedal driving is more efficient... Its great for going down hills, but I think it is actually less efficient because there is very little "gliding" where the car is just rolling. Instead there is always a little thrust or a little regen. Since these are not 100% efficient systems it is energy loss compared to gliding.

--Bob

Click to expand...

Exactly right. It's a misconception that "more" regen is "more" efficient. Regenerative braking only recovers a fraction of the energy used in getting the car moving. In terms of maximum efficiency, it's always best to use coasting / gliding and preserving momentum when possible. Any braking (regenerative or otherwise) wastes energy.

Better control of regen, combined with an understanding of when to best apply it, is what is most efficient. I typically either want one of two modes:

1) one-pedal driving with full regen to a complete stop
2) no regen whatsoever on the accelerator - take your foot off to coast

Driving my EV, I quickly realized that no one really needs adjustable regen modes and that "better control" is done with one pedal driving. Coasting is achieved simply by lifting of the throttle to the neutral point between accelerating and braking.

Meh. Needs and wants are two different things. I never said I *need* it, only that I want it.

I've been driving my Leaf for 4.5 years now. Keeping the accelerator in the sweet spot for coasting is old. In fact it is quite tiring to try and find it. If the Bolt (or any EV) has a nice, wide, easy-to-find, coasting position on the pedal, that's fine. But it would be even better if I didn't have to try to find it. I would love to "find" it by simply taking my foot off the pedal.

Fair enough. I've only been driving my EV for a few months, and "finding neutral" with one pedal is a whole lot easier than the constant shifting into neutral (what I did with my TDI). After a few years, I may be in your camp too.

rbroders said:

I don't know why they think one-pedal driving is more efficient. Its not like the brake pedal uses the brakes. The brake pedal initiates regen. Actual friction brakes aren't used unless you press harder than the regen can handle.

My Spark EV has a D and L mode. In L mode taking your foot off the gas immediately starts regen braking. Its great for going down hills, but I think it is actually less efficient because there is very little "gliding" where the car is just rolling. Instead there is always a little thrust or a little regen. Since these are not 100% efficient systems it is energy loss compared to gliding.

--Bob

Click to expand...

I agree entirely, Bob. I hope there is a "coasting" point in the accelerator pedal that is easy to find. Otherwise, I will be shifting it into neutral, like I do on our Leaf.

Our e-Golf gets the coasting / regen design just about right. It coasts when you lift your right foot in D, and has regen fully integrated on the brake pedal. There are also 4 different levels of regen when you lift your right foot, selected on the "shifter".

NeilBlanchard said:

I agree entirely, Bob. I hope there is a "coasting" point in the accelerator pedal that is easy to find. Otherwise, I will be shifting it into neutral, like I do on our Leaf.

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I hope that's possible, but the photos I've seen of the Bolt EV's shifter knob show that "P" is in between "D" and "N". If it really works that way then shifting between "D" and "N" while moving may not be a pleasant experience.

I'm hoping that the "P" position shown on the knob is really just a light that illuminates when you push the "P" button on the shifter, and not an actual position that can be selected just by moving the knob forward or backward. Even so, it seems like an odd place to put the light - if it really works that way then a light in the "P" button itself would make a lot more sense IMHO.

I think it is like the Leaf shift "puck" - it springs back to the center position. And like the Leaf, you cannot put it in R above 7MPH, and so it goes into neutral instantly; so this is much quicker than holding it in N for 2s.