Transport Evolved

[mpt]

Roadster and MINI E already have a coast mode; just hit N on transmission then back to D, it's really easy, especially in Roadster, the buttons just fall to hand. You have to position the accelerator carefully as you re-engage D, if you do it with your foot off the accelerator the car engages full regen in a snap.

Tesla have said in the past that the regen is fixed as it's a predictable force that, if altered, mucks up the traction control calculations.

 

[JRP3]

As you describe I'd imagine that transition may not always be smooth. Theoretically there must be an accelerator position that neither sends power to the motor nor calls for regen which would allow true coasting, but maybe it's too small to find and hold steady with your foot. I'm not sure I buy the idea that variable regen would mess up traction control, you actually vary regen all the time as you drive using your foot.

 

[TEG]

Aside from overshooting intended speed when passing/merging (since it is so tempting to "engage the warp drive"), I find that cruising along in the Roadster it is very easy to keep a steady state speed with the accelerator pedal just held at the position you need. I much prefer this "rest your foot on the pedal to coast" with the ability to do one pedal slow down over the "still coast when you let go" approach.
In other words, I think it is easy to find the speed appropriate coast position in the Roadster with the accelerator pedal. If the "coast region" was very small one would think you would need to keep adjusting the pedal up and down between regen and acceleration, but I don't think you end up needing to do that much if maintaining a steady speed.

 

[Doug_G]

I don't think any manufacturers are going to zero A pedal regen, I assume they are trying to make them feel similar to typical automatic ICE's.

Yeah but they're not the same; they should take advantage of their advantages!

 

[mpt]

Yeah but they're not the same; they should take advantage of their advantages!

... and kill the creep! MINI E in traffic is nicer to drive than the roadster as you don't have to hold the brake but that's a whole other debate on another thread.

 

[Doug_G]

As you describe I'd imagine that transition may not always be smooth. Theoretically there must be an accelerator position that neither sends power to the motor nor calls for regen which would allow true coasting, but maybe it's too small to find and hold steady with your foot. I'm not sure I buy the idea that variable regen would mess up traction control, you actually vary regen all the time as you drive using your foot.

I regularly "prime" my foot position prior to popping off the cruise control. It's easy to find the right position, and no I don't push until it starts to accelerate. At most I might slow down a few kph, but usually I'm almost bang on.

 

[Doug_G]

... and kill the creep! MINI E in traffic is nicer to drive than the roadster as you don't have to hold the brake but that's a whole other debate on another thread.

I can see two reasons to keep the creep:

1. It tends to keep the car from rolling backwards when starting on hills; people used to automatic transmissions will be really caught off guard if it rolls back
2. When stopped you should really keep your foot on the brake for safety reasons; otherwise if someone bumps you from behind you'll really go flying

 

[JRP3]

No creep in any manual shift ICE vehicle, nor in my EV. People do need to be able to adapt to some degree. I regularly transition from driving a manual ICE, auto ICE, and EV. As you say take advantage of their advantages.

 

[mpt]

I can see two reasons to keep the creep:

1. It tends to keep the car from rolling backwards when starting on hills; people used to automatic transmissions will be really caught off guard if it rolls back
2. When stopped you should really keep your foot on the brake for safety reasons; otherwise if someone bumps you from behind you'll really go flying

1, The MINI E holds the brakes for you; it has hill start assist, 2, True indeed though I tend to release the brake when I'm in bumper-to-bumper traffic against a light or SVoT. I find it relaxing as I find that when I hold the brake I involuntarily hold it hard enough to stop a truck - don't know why just do!

 

[JRP3]

Hills are easily handled in an EV by using both feet if necessary, or just a quick transition from brake to accelerator.

 

[TEG]

The Leaf creeps a little bit in both forward and reverse.
Probably not enough for full hill holding on steep hills as the dealer said to use the aux parking brake (which is a two position switch) in that case.
Leaf regen seems very modest off pedal compared to other EVs I have driven. In some cases it doesn't seem to be doing any regen at all (full coast), but some factors (such as being in ECO mode) will start to add a little off pedal regen. It isn't until you start pressing the brake pedal that you get full regen going.

 

[Jaff]

Agreed Doug...with a little practise, it's not hard to achieve a smooth re-entry to normal driving from cruise control...it's part of driving the car.

Regen rules! :wink:

I regularly "prime" my foot position prior to popping off the cruise control. It's easy to find the right position, and no I don't push until it starts to accelerate. At most I might slow down a few kph, but usually I'm almost bang on.

 

[TEG]

Another Leaf thing I noticed - you don't get full regen unless you push the brake pedal about half way down. But then if you push even harder the regen backs off again.
So it seems that their blending algorithm will start to disable regen as the friction brakes fully take over. Not sure why they decided to do that. Maybe something to do with ABS?

 

[Norbert]

Maybe have full regen on the power pedal, but a slightly longer coast zone between power and regen, and then have a green circle light up which you can see out of the corner of your eye. Or the power display itself changes color from light blue (or white) to green (for coast) and then to red or orange (for regen)... ?

 

[SByer]

Meh. Automatic transmissions helped ruin the driving ability of the American public. Continuing any of those traits forward seems like a waste. If you can't go down a steep hill without constantly being on the brake pedal, you've devalued the signal the brake lights are supposed to provide to the drivers behind you. On the other hand, I like that the Roadster's brake lights come on if I lift off the pedal quickly - that extra fraction of a second gives me a little more padding from the bonehead behind (compared to the engine braking in the 911 which always seemed to surprise the idiots).

Though I still strongly suspect creep was a way of sneaking out any drivetrain lash, especially when they were trying to extend the life of the 2-speed transmissions. I'd like to experiment driving without it for a week to see if it helps or hurts.

There are a couple of freeways around here which were constructed in a way that, now that they've aged, gives them an annoying repetitive undulation (I'm looking at you, Highway 85) at a frequency that probably defines the Roadster's minimal pedal response lag - any shorter and the natural pedal fluctuations my foot causes as the car goes over these road waves would add an annoying acceleration/deceleration component. I still don't have any problem finding an appropriate 'coast' position (within butt-detection tolerance). It's still such a low latency on pedal response that it blows any ICE car out of the water.

 

[JRP3]

Maybe have full regen on the power pedal, but a slightly longer coast zone between power and regen, and then have a green circle light up which you can see out of the corner of your eye. Or the power display itself changes color from light blue (or white) to green (for coast) and then to red or orange (for regen)... ?

That's what I've been suggesting, and what BMW seems to be doing with the ActivE. However I prefer real numbers to lights and my current gauge tells me exactly how many amps I'm using, or putting back into, the battery pack. Zero amps either way tells me I'm coasting. I'd like to see more automakers use real numbers like amps or kilowatts, and amp hours or kilowatt hours.

 

[Norbert]

That's what I've been suggesting, and what BMW seems to be doing with the ActivE. However I prefer real numbers to lights and my current gauge tells me exactly how many amps I'm using, or putting back into, the battery pack. Zero amps either way tells me I'm coasting. I'd like to see more automakers use real numbers like amps or kilowatts, and amp hours or kilowatt hours.

I'd prefer numbers as well (kW and kWh/mile), however additionally colored areas (or the numbers colored, on a LCD) so that one can tell, without taking the eyes off the street, whether one is getting out of the coasting zone at the lower, or at the higher end, and accordingly respond on the power pedal. If possible, the colors would change before one actually leaves the coasting zone (kW still zero), so that on can stay within the zero kW range. If in practice this works well enough to become an almost instinctive process...

EDIT: Or maybe to have tactile feedback at the zero point (perhaps additionally)...

 

[TEG]

EDIT: Or maybe to have tactile feedback at the zero point (perhaps additionally)...

"Haptic pedal"...

 

[JRP3]

That might be going too far. Just enough of a neutral area so you can hold it easily, and you can still pass through it easily if you just want regen. Mine is almost there, just need a little bit more neutral zone and I'll be happy.

 

[vfx]

Agreed Doug...with a little practise, it's not hard to achieve a smooth re-entry to normal driving from cruise control...it's part of driving the car.

Hate that the brake light come on though.

And loose the creep!