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Does the cruise control use regenerative braking to maintain speed going down hill? With an ICE car, the cruise control does a good job of maintaining set speed on flat ground and a pretty good job going up hill, but if you go down a grade that exceeds the car's engine braking capability, the set speed gets exceeded. With the Bolt it seems the regenerative braking could keep you exactly on speed and boost your range no matter the grade.

Is this so? Just wondering.
 

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Does the cruise control use regenerative braking to maintain speed going down hill? With an ICE car, the cruise control does a good job of maintaining set speed on flat ground and a pretty good job going up hill, but if you go down a grade that exceeds the car's engine braking capability, the set speed gets exceeded. With the Bolt it seems the regenerative braking could keep you exactly on speed and boost your range no matter the grade.

Is this so? Just wondering.
It does and it keeps at speed even at steep hills. I keep at 75 and drive on interstate for 23 min each way and have never seen it move, up or down. Does way better than my Chevy Suburban, it varies 5-6 mph.
 

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In a time far ago going to Z06 fest in Bolling Green
Hurricane made way up from Gulf
At least two Z06's had bad accidents due to the way cruise control normally functions. Not supposed to use cruise in poor weather but things happen
Our vehicles have great tech for such circumstances better regulation and traction control on for sure when using speed control.
Time marches on
 

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You will see that while using L and maintaining say 75 mph, you will note 40 to 50 KW sometimes being put into the battery by the very bottom of a down hill run. All that seamlessly, while maintaining your exact speed. L, except for the name, is the greatest creation by GM engineers. It does a perfect input and output, all down to the microsecond. Various combos of drive, flipper and a brake that takes you out of cruise, ...all cannot keep up with the microsecond adjustments of L in cruise.
 

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That was one of the first things I noticed driving the Bolt. The speed is rock solid, never varies from its setpoint in cruise control. I rented a car about once per month or more for years for work and every one of them would speed up downhill and slowdown then downshift and loadly rev the engine and lurch uphill.

With electric motor it is all in smoothly varying the rotational speed of the magnetic field produced by the field coils relative to the rotational speed of the motor shaft (rotor) connected to the drivetrain. Motor field faster, motor applies torque to the drivetrain (motor mode), motor speed slower the drivetrain applies torque to the motor (generator mode, "braking"). It is continuously monitored and smoothly varied to supply the amount of torque or braking required so you rarely notice anything changing as you travel along at constant speed seamlessly regardless of terrain. If a luxury gas car had a similar capability they would be advertising it like crazy.
 

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I noticed when in cruise that if I hit + to add 1 mph, I feel an actual short burst of acceleration as it immediately adds the 1 mph, and likewise, when hitting - to subtract 1 mph, I feel an actual short burst of deceleration. That is, the cruise control seems so impeccably accurate as to be discretised.
 

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You will see that while using L and maintaining say 75 mph, you will note 40 to 50 KW sometimes being put into the battery by the very bottom of a down hill run. All that seamlessly, while maintaining your exact speed. L, except for the name, is the greatest creation by GM engineers.
Cruise control uses regen to maintain speed while going downhill even in "D" mode.
 

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Cruise control uses regen to maintain speed while going downhill even in "D" mode.
In all cases, the regen in D is minimal compared to L. Other pluses are automatic decreasing speed for off ramp, just by touching the flipper and dropping out of cruise while in L. That, of course, is very heavy regen. Need some more to stop? Just go back and add the flipper to what L is doing to stop. Where I live, I am allowed to only very rarely have to use my brakes. And even then, it is lightly to make sure I am in a complete stop before going into Park. Too many positives for L. That explains why Tesla and VW engineers have been very impressed with the Bolt L mode. There is little else about the Bolt that impresses those engineers.
 

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In all cases, the regen in D is minimal compared to L.
At least with respect to our 2019 Bolt, I disagree. Using D with cruise control coming down Mt Hood (for example, ie, long sustained steep roads), the car very strictly maintains the set speed. I've even experimented, switching between D and L. Zero difference.

Possibly it was different for previous years...
 

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At least with respect to our 2019 Bolt, I disagree. Using D with cruise control coming down Mt Hood (for example, ie, long sustained steep roads), the car very strictly maintains the set speed. I've even experimented, switching between D and L. Zero difference.

Possibly it was different for previous years...
I never see 40 to 50 KW coming in, at the base of a steep incline, while in cruise and D. I have never seen anything above 20 KW coming back into the system, in D. The only thing that I dislike about L is its label "L". It is a misnomer that leads to ridiculous discussions. That label is certainly confusing to a new Bolt owner. Have you ever seen the posts by Uber Bolt drivers, who drive hundreds of thousands of miles? They all use L.
 

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I never see 40 to 50 KW coming in, at the base of a steep incline, while in cruise and D. I have never seen anything above 20 KW coming back into the system, in D. The only thing that I dislike about L is its label "L". It is a misnomer that leads to ridiculous discussions. That label is certainly confusing to a new Bolt owner. Have you ever seen the posts by Uber Bolt drivers, who drive hundreds of thousands of miles? They all use L.
D means Don't like, L means Like. Simple.
 

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I have never seen anything above 20 KW coming back into the system, in D.
Maybe your hills aren’t steep enough? I just ran my test again on a long steep hill near my neighborhood.

Using L, cruise control set at 35, the speedometer read 36, regen was bouncing between 26 and 27 kW.
Using D, cruise control set at 35, the speedometer read 37, regen was bouncing between 26 and 27 kW.

I’m gonna call that “the same” within the margin of error.
 

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Maybe your hills aren’t steep enough? I just ran my test again on a long steep hill near my neighborhood.

Using L, cruise control set at 35, the speedometer read 36, regen was bouncing between 26 and 27 kW.
Using D, cruise control set at 35, the speedometer read 37, regen was bouncing between 26 and 27 kW.

I’m gonna call that “the same” within the margin of error.
Southern Rockies in NM. I see 45 to 55 KW INPUT, while at the base of a US highway standard grade (I25) while in cruise at 75 mph only when in L. 25KW to 35KW input while in D, at the base of the same hill. I will leave this topic now, to Eric Way and the many Uber drivers who use L constantly, in the city or on the highway. I defer to their need to max out each and every day. All these stories are anecdotal, until GM or a standard testing service does the real testing and releases the results.
 

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All these stories are anecdotal, until GM or a standard testing service does the real testing and releases the results.
Fair enough, though I’ll trust my own tests and experience in the meantime.

I still wonder, however, whether the behavior is different between model years. So far, I see -nothing- in the performance of my 2019 to suggest that there’s any difference in regen between L and D when driving the same acceleration/deceleration profiles.
 

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Fair enough, though I’ll trust my own tests and experience in the meantime.

I still wonder, however, whether the behavior is different between model years. So far, I see -nothing- in the performance of my 2019 to suggest that there’s any difference in regen between L and D when driving the same acceleration/deceleration profiles.
Our 26 month old Bolt LT shows absolutely no difference between L and D, in cruise control.
 

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Fair enough, though I’ll trust my own tests and experience in the meantime.

I still wonder, however, whether the behavior is different between model years. So far, I see -nothing- in the performance of my 2019 to suggest that there’s any difference in regen between L and D when driving the same acceleration/deceleration profiles.
Thought I was done, but have to agree with you...something is different. As I look at all the posts on this subject here, and at other sites, I would be more inclined to interpret your findings as something being wrong with your L. It is designed to produce much more regen during all applications. That was its original introductory reason for being. If it were not, then, your choice of D would make no difference. But topic after topic, post after post, here and other sites, stress the original intent of L by the original engineers, to max regen... If I had your results, I would be taking it to the dealer and complaining.
 

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Thought I was done, but have to agree with you...something is different. As I look at all the posts on this subject here, and at other sites, I would be more inclined to interpret your findings as something being wrong with your L. It is designed to produce much more regen during all applications. That was its original introductory reason for being. If it were not, then, your choice of D would make no difference. But topic after topic, post after post, here and other sites, stress the original intent of L by the original engineers, to max regen... If I had your results, I would be taking it to the dealer and complaining.
Perhaps you're misunderstanding my meaning. With L I will get more regen if I remove my foot from the pedal, no question. But if I feather the pedal (or use cruise control, or even moderate brake pedal) such that the cars are accelerating/decelerating/holding speed in the same way, then I see no difference in the amount of regen.

To my mind, this is exactly as it should be. If you want one pedal driving, go with L. If you want the more traditional "coast" when you take your foot off the accelerator, go with D. If you have two Bolts, one in L and one in D driving the same pattern of speed, acceleration, deceleration - they should both show the same amount of regen.

For the behavior to be different would require the car in D to be applying friction brakes when there is still the ability to use regeneration. In other words, killing efficiency needlessly.

If I saw that behavior, then I would be complaining. But I don't. If you're seeing it, then I suggest that the problem is with your car. For what it's worth, other postings in this thread (and other threads) agree with me...
 

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Southern Rockies in NM. I see 45 to 55 KW INPUT, while at the base of a US highway standard grade (I25) while in cruise at 75 mph only when in L. 25KW to 35KW input while in D, at the base of the same hill. I will leave this topic now, to Eric Way and the many Uber drivers who use L constantly, in the city or on the highway. I defer to their need to max out each and every day. All these stories are anecdotal, until GM or a standard testing service does the real testing and releases the results.
You are saying that, at the same speed, on the same downhill stretch, you see a 20 KW difference in regen between D, and L, in cruise? My question is, "Where did the other 20 kW of kinetic energy go, when in D?"
 
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