D, ECO or B modes

[JoeS]

Admittedly, it can be fun to play with the shifter under various conditions when slowing down...but the bottom line is, it is no different than using the brake pedal judiciously. The brake pedal is a continuously variable shifter.

Understand that, but Mitsubishi did such a great job of implementing the transition from regen to hydraulics that I have no 'feel' for when the brakes themselves actuate.

Don't know if this feature with brake lights coming on when regenerating is added on US-sold i-Mievs, but here in Europe i-Miev-clones Peugeot iOn and Citroen C-Zero has received this feature from MY2015. I haven't checked for Euro-spec i-Miev, but guess it is the same.

I just sent an email to my good friends in New Orleans who bought a 2016 i-MiEV to see if deceleration-based brake light actuation has now been implemented on North American vehicles.

 

[tigger19687]

Would this be implemented in an Electronic Update ?

Just curious. Glad this was mentioned as I am now much more aware of who is behind me.

 

[PV1]

Regen brake lights would require a software update to the car, and possibly some wiring changes. I don't believe the car's computers have control of the brake lights as it is now.

While true that the brake pedal is great for varying the regen, it is still sensitive to which drive mode you are in. Pressing the brake pedal in B mode gives you more regen than ECO or D, same for ECO vs. D as well. With precise timing of shifting to B and pressing the brake pedal, I was able to hit 45 kW regen.

 

[Aerowhatt]

Regen brake lights would require a software update to the car, and possibly some wiring changes. I don't believe the car's computers have control of the brake lights as it is now.

Actually, I have done this before and it can work with the car and computer as is. Non invasive sensing of main pack current flow from the cable to the inverter. Current into the pack above a certain threshold closes a NO relay in parallel with the brake light switch energizing the brake lights. I'm happy with my more sensitive brake light switch adjustment for the time being. But I would prefer not having to actively think about making sure the brake lights are illuminated when slowing.

Aerowhatt

 

[sandange]

We had a tread for Regen brake lights if you're interested.

http://myimiev.com/forum/viewtopic.php?f=22&t=2405

 

[Aerowhatt]

Thanks Sandage

I will move over there with this brake light aspect of the topic.

Aerowhatt

 

[fjpod]

Basically, if you want a brake light when using regen...use the brake pedal. As long as you keep the needle somewhere below the maximum regen possible, you will not be using friction.

 

[kiev]

D Mode
The “D” position is the standard mode; it provides full power access and a normal regenerative braking effort.

In this mode, the vehicle delivers “direct response,” meaning that full throttle means you get 100% of all available torque—instantly.

Can drive in this mode all the time but it won’t maximize the battery’s efficiency.
Best used when accelerating on to the highway and going uphill.

Eco Mode
The “Eco” mode slightly modifies the motor’s response curve to conserve battery, and provides a slight increase in the regenerative braking capability.

This mode is best for around town where you have a lot of stop and go driving.

B Mode
The “B” mode provides full power – the same as the “D” position—with the strongest calibration of regenerative braking capability.

This mode is the best for traveling down hill.

Bear in mind, a person could feasibly drive their car full time in any one of these modes, but when they learn the strengths of each mode, they can maximize the battery’s efficiency by shifting into these various drive modes at any time during their commute.

Shift Position
Selecting the most suitable shift position is important for extending your range.
“D” is the standard mode and provides full power access and normal regenerative braking effort.
“Eco” slightly reduces overall power output thus conserving energy and slightly increases the regenerative braking capability.
“B” provides full power with the strongest calibration of regenerative braking capability

Stepping on the Accelerator
Drive smoothly, accelerate gently and read the road ahead

You may check your real-time energy consumption by looking at the power meter. Try to keep the red needle within the green “Eco” zone. When the vehicle is braking (regenerating energy), the red needle should be in the blue “Charge” zone.

When you are driving on freeways, set a desired speed at or near the speed limit and try to keep a consistent speed. The faster you go, the greater the energy consumption.
When decelerating, try to release your foot off the accelerator pedal as early as possible. The moment you release your foot off the pedal, the vehicle will start regenerating energy and is especially efficient when you are driving downhill.
When driving uphill, try to carry as much speed (momentum) from the flat section of road up the hill as possible to avoid having to accelerate in the middle of the hill.

 

[tigger19687]

I think I broke the ECO mode. Or I have gotten used to the way the pedal is.
Seems like it isn't as hard to push the throttle down like it was last week when I bought the car.

 

[genec]

Thanks for posting those images about gearing.

It looks like ECO mode is the best overall mode to keep it in.
D mode for steep uphills.
B mode for steep downhills.

I would like to do a few round trip tests in each mode to compare battery conservation.

 

[PV1]

ECO seems to utilize a two-step resistance design of the throttle pedal. Right where full power is in D and B is roughly half power in ECO, and pushing the pedal beyond that has more resistance, most likely a second spring engaging in the pedal mechanism. I suppose you'd get used to this, but also the spring would loosen up just a bit by being used (the previous owner could have never used ECO).

Most likely, you're getting used to it

I pretty much live in ECO, but do a lot of shifting. Sometimes I use B(oost) mode to jump in front of somebody or to climb a hill, but I mostly use B(rake) mode when stopping.

 

[JoeS]

ECO seems to utilize a two-step resistance design of the throttle pedal...

No, that was disproven a year or two ago when I made that assertion. It's all a gain-change in the software; however, when you floor it in ECO mode you do get full power! Really nice safety feature.

 

[PV1]

Sorry, I meant physical resistance. The bottom half of the pedal travel, the portion that only ECO takes advantage of, feels like it is physically harder to push than the top half of travel. ECO itself doesn't change anything with the pedal other than the sensitivity which, like you said, is all in software.

Then again, maybe it's just the pedal in Bear. I noticed when I drove Koorz the other day that the pedal was much easier to push over the entire pedal travel, resulting in breaking a couple of speed limits .

Yes, full power in ECO is a must, and I'm glad the i-MiEV has that capability, even if the "reviewers" don't know about it.

 

[sandange]

+1 Kiev That's how I Drive

 

[JoeS]

Sorry, I meant physical resistance. The bottom half of the pedal travel, the portion that only ECO takes advantage of, feels like it is physically harder to push than the top half of travel. ECO itself doesn't change anything with the pedal other than the sensitivity which, like you said, is all in software.
Then again, maybe it's just the pedal in Bear. I noticed when I drove Koorz the other day that the pedal was much easier to push over the entire pedal travel...

I also thought the pedal was 'harder' to push in ECO. Had this discussion in July 2013: http://myimiev.com/forum/viewtopic.php?p=11853#p11853

 

[RobbW]

I noticed something peculiar about D and Eco modes this morning and am curious if it's just me. I've had my Meepster for over 2 years now and STILL have not been able to settle on any one particular drive mode for the majority of my driving. If I put my Meepster into one drive mode and just leave it there, I can't help feeling that I may be missing out on some efficiencies or range benefits by NOT driving in another mode (or just constantly running the gates).

Anyway, I was doing some testing between the different modes this morning on my commute into work. We know that Eco mode uses a software governor to reduce the sensitivity of the go-pedal. I use Eco frequently in a mostly futile effort to control my heavy-footedness. In my experience, I have noticed that while Eco mode requires the driver to press down more on the go-pedal to get up to the same speed as in D/B modes, as long as you keep the power needle pegged in the exact same position, the car will always go the same speed (on a straight-away) regardless of which drive mode you are in.

This morning, I was noticing something odd about the difference between D and Eco modes. As we know, Eco mode reduces the sensitivity of the accelerator and requires much more travel of the go-pedal in order to get up to the same speed as in D (or B) mode. Now, this may have been discussed/explained in other threads in the past, but I was under the impression that this was simply a software setting for Eco mode and really only affected the sensitivity of the accelerator. However, doing some experimenting this morning, I'm thinking that Eco mode must engage other mechanical limitations, as well. In several experiments in both D and Eco modes, from a dead stop, I immediately pressed the accelerator with enough force to peg the power needle to a specific location. Even though, according to the power meter, I was supposedly outputting the same amount of power in both modes, the acceleration ramp in Eco mode was significantly dampened and took much longer to get up to speed than in D mode. So, it can't just be a software limitation that is reducing the sensitivity of the accelerator. It must be limiting the output at the motor, as well, right?

Also, I noticed that in D mode, after initially pegging the power needle to the designated test point I was using, as the car accelerated up to speed, the power needle actually started to climb more even though I was not applying any additional force on the accelerator. I had to left off the accelerator in order to maintain the power needle at the same point. Conversely, in Eco mode, as the car accelerated up to speed after initially pegging the power needle to the test point, the power needle started decreasing as I got closer to the test speed. I had to press on the accelerator more in order to maintain the power needle at the designated point.

Is this expected behavior?

 

[RobbW]

I added my arm rest and taller shifter mostly for this.

What shifter did you add to raise its height? I would like a taller shifter myself. However, the only taller shift knob I have tried so far was the type that slips on and is retained by a locking screw. I did not like this as the shift knob kept rotating no matter how tightly I screwed in the retaining screw. I'd rather have the type of knob that fully screws onto the existing threads. For now, I've gone back to the OEM knob.

 

[JoeS]

RobbW, you nicely described the vehicle's behavior in Eco Mode. There is a 'gain' change in the car's response to accelerator pedal position between D/B and Eco; however, it is non-linear, as 'flooring' the accelerator will indeed give you full power. Pedal position translates into current being fed by the controller into the motor, recognizing the 2-3 second time delay in initial acceleration. This current will decrease as the car gets up to speed and the pedal is held steady.
Edit: I believe this last statement to be incomplete, within limits. Discussed further on in this thread (9/24).

Also, I noticed that in D mode, after initially pegging the power needle to the designated test point I was using, as the car accelerated up to speed, the power needle actually started to climb more even though I was not applying any additional force on the accelerator.

RobbW, this is normal response in all three modes during the initial 2-3 seconds of acceleration; however, you bring up an interesting point, and one I've never paid attention to: maybe in Eco mode there is an additional time-delay element associated with pedal depression (not release) that is not present in the other two modes. Basically, acceleration-response dampening. Interesting hypothesis worthy of further pursuit. For deceleration (regen) I'm so happy the i-MiEV responds instantly.

 

[RobbW]

Thanks, Joe. It is all very interesting!

After reading through this and other threads comparing the different driving modes, I'm still left wondering if there is any definitive insight into which mode would be best for efficiency/range conservation if just left in that single mode? If every variable were exactly the same, would one single mode be better for maximizing range than another? For example, I have the exact same round-trip commute to and from work every day. The weather forecast for all this week is supposed to be almost exactly the same every day (80° and mostly sunny). My driving style during my commute is pretty much invariable recently. If each day I chose one drive mode and left it in that mode for the entire round-trip commute, would I see any significant difference in my RR, MPkWh, energy consumption, or any other pertinent metric? Or would any difference in such a driving scenario be so insignificant as to not merit worrying about it?

Would "running the gates" and constantly using all three (four if counting N) modes have any significant benefit/difference compared to driving in one single mode all the time? (other than not having to constantly put my coffee down to shift gears!)

 

[JoeS]

Would "running the gates" and constantly using all three (four if counting N) modes have any significant benefit/difference compared to driving in one single mode all the time? (other than not having to constantly put my coffee down to shift gears!)

RobbW, an individual driver's driving technique and variability make any comparison of driving modes in almost any traffic setting impossible, IMO. If you have CaniOn, just look at the wH/km readout - do a trip reset every morning and see what you get running for a week in one mode only. I bet the number is different every day! By the same token, I defy anyone to predict what their RR is going to be after a full charge.