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The origin of the 'B' mode setting.

Posted: Sat Jan 21, 2017 10:02 pm
by JejuSoul
The 'B' mode setting on the Soul EV gear stick is an awful design decision, so I was wondering why they did it.
I think I found the answer while on vacation in Japan.
I just spent a week driving a Toyota Aqua. In the US this car is known as the Prius C.
Here is the gear stick.

Image

On the Prius the 'B' mode setting is for Engine Braking.

It is explained here - Questions about B Mode

Use the B position of the Mode Selector Lever in exactly the same circumstances as you would change to a lower gear to slow down a conventional car. If you are going down a long and steep hill, controlling the car's speed using only the brakes can cause them excessive wear, get them hot and may also tire your foot. The solution in a conventional car is to select a lower gear. The engine then spins faster and the energy it takes to do this holds back the car. Less brake pressure is needed to maintain a slow rate of descent. The Prius, however, has no gearbox in the usual sense of the term. Toyota have made special provision for engine braking and to activate this you put the Mode Selector Lever in the B position. By a special configuration of the motor/generators, the engine spins and helps hold back the car just as in a car with a gearbox.

....the purpose of B mode is to throw energy away by spinning the engine.

On a Prius the 'B' mode setting saves the friction brakes from overheating when going down a hill, by using the electrical motor (in reverse) to slow the car down. The recuperated energy cannot all be saved in the battery, so it is 'wasted' by spinning the engine. The Prius has a small HV battery ~1kWh and cannot recuperate more than about 10kW.

The 'B' mode setting was copied by Nissan for the Nissan Leaf, and then Kia copied it from Nissan. But on a fully electric car this setting is not the same thing. It cannot be Engine Braking because a BEV has no mechanical engine into which energy can be 'wasted'. There is no longer a need to 'waste' recuperated energy because it can be saved into the battery. The Soul EV can recuperate more than 43kW.

What the 'B' mode setting actually does on a BEV is alter the level of recuperation on the accelerator pedal. It is about one foot driving. This mode is far better altered on the I oniq EV using paddle shifters. Hopefully the next generation of Kia EV's will lose the 'B' mode too.

( a different topic - the Prius gear stick being set diagonally is a much better design than the Soul EV which is straight. Just like the Soul EV if you accidentally push the stick into 'P' while driving; a mechanical b olt will be pushed into the transmission to stop it. This destroys the transmission. It's much less likely with the diagonal configuration than the straight.)

Lol - I just noticed how stupid this website is. It translates my use of the word metal 'b o l t' into the car 'B o l t'.

Re: The origin of the 'B' mode setting.

Posted: Sun Jan 22, 2017 10:06 am
by MrFlibble
B Mode is equavent to L mode on other systems.

The Bolt has an L instead of B, but it is the same thing.


I think B mode is great, because, in the case of the Soul, it absolutely charges the battery, and increases braking force through regen. I use D on the highway as I want a longer glide when my foot is off the accelerator, and B everywhere else.

It is part of the design that drew me to the Soul.

Re: The origin of the 'B' mode setting.

Posted: Sun Jan 22, 2017 11:15 am
by SoulEV2016
If we follow the Ioniq strategy, the futur soul EV may have the "auto mode" button to choose between 3 modes.
It's like this that you can use the highway setting (D mode) or the city/inter-urban setting (B mode).

I don't like the paddles behind the wheel (because i want a predicted regenerative brake, so B is always used in my soul EV, i have not drived in D mode since i have my car).

Re: The origin of the 'B' mode setting.

Posted: Sun Jan 22, 2017 9:47 pm
by JejuSoul
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The reason that having a 'B' mode setting on the Soul EV gear stick is an awful design decision is because it confuses everyone.

If our 'B' mode was called Level 2 Regeneration and was accessed via the Navi and not the gear-stick I think people would be less confused.

Image

The picture and example below is from the I_o_n_i_q_EV. If you want to understand regen better I suggest you test drive an I_o_n_i_q_EV.

If you want to stay in the same mode all the time set it via the Navi. If you want to swap during driving then use the paddle shifters.
An example: coming down a steep winding mountain road I find it most comfortable in level 3. But at the bottom part of the hill, if the road straightens out I will use level 0 (no regen = 'N') to gain the maximum rolling speed to go up the next hill.

There is no difference in energy saved between using the different levels of regen and just using the brake pedal harder or softer. It is just a personal choice - do you prefer one-foot or two-foot driving.

The only way to save energy is to not use regen or brakes at all. (on the Soul EV the only way to get no regen is by putting the gear-stick into 'N'). I strongly recommend NOT to use this method on the current Soul EV because of the badly designed gear-stick. If you go into 'P' by mistake you will destroy the transmission.

Re: The origin of the 'B' mode setting.

Posted: Mon Jan 23, 2017 10:46 pm
by MrFlibble
Image

That gear position has been around a long long time. People know it by muscle memory without having to look. Shifting into P while moving is a rare thing, people don't do it often.

I haven't met anyone who is confused by the gear shifter in my Soul EV, and I have never heard complaints on any reviews about B mode and the shifter. Most people like it, and as I said, it stormed to the Soul EV.

I agree that being able to tweak the amount of resistance that regen provides would be a good thing, but I disagree that it should be on the nav. Having something that requires you to take your eyes off the road to engage/disengage is a bad idea. You should be able to do it by feel.

I like that I can shift between D and B, even with cruise control on, and not disengage cruise. This is handy for me as I commute along a rural highway where sometimes I need to be in B, and sometimes D is more efficient.

I do wish I could alter the amount of pull B had, but that is a minor quibble overall.

Re: The origin of the 'B' mode setting.

Posted: Tue Jan 24, 2017 12:41 am
by JejuSoul
MrFlibble wrote:That gear position has been around a long long time.

That is exactly why it shouldn't be there on the Soul EV.
Everyone knows what a low gear on an ICE car is. An EV doesn't have gears.
It's silly to confuse people by pretending it does.

What car is the picture?

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Note: I really like my Soul EV. I too almost always drive in 'B' mode. But this doesn't stop from wishing this car was better.

Here's an example of what I'd like to see.
One of the steering wheel buttons is labelled 'mode'. It has a little steering wheel icon.
When pushed it adjusts the steering wheel setting from 'normal -> comfort -> sport.

If however this was the 'regen' button. When pushed it adjusts the regen setting from 'level 0' -> 'level 1' -> 'level 2'
This is all software controlled. Every year or so an update tweaks the settings so we get extra levels.

Think about it; ICE cars never get a software update to add more gears.
My existing Soul EV will never get a new gear-stick.
The 'regen' on the accelerator pedal is just software . It can be updated easily.
Sadly unless you own a Tesla it never will be.

Re: The origin of the 'B' mode setting.

Posted: Tue Jan 24, 2017 7:36 pm
by acadiandad
My contrarian view. The shifter design of the Soul was a major reason I bought the car. I wanted something for all the others in my family that was perfectly intuitive for them to drive just like the Auto transmission ICE cars we already have. They've learned safe driving on snow and the importance of being able to move to N in a split second without thinking.

For me, the beauty of the Soul is that it ISN'T different than the ICE version in many respects. It's good, basic transportation and happens to be an EV.

I'd be even happier if it still hand a hand brake like all cars should have (but seems I'm losing that battle as more and more cars implement pedals and push buttons).

My $0.02 anyway.

Re: The origin of the 'B' mode setting.

Posted: Tue Jan 24, 2017 10:47 pm
by GizmoEV
JejuSoul wrote:There is no difference in energy saved between using the different levels of regen and just using the brake pedal harder or softer. It is just a personal choice - do you prefer one-foot or two-foot driving.


It isn't quite that way on my 2016 Soul EV+. I have a steep off ramp near me and I tried using both D and B when slowing down from 70mph going down the hill. While regen did increase the harder the brake pedal was pushed, the regen was higher in B mode for the same deceleration rate as evidenced both by feel and the regen value given on the NAV display. In B mode the brake pedal pressure had to be relaxed when in B mode compared to D mode.

I do wish that regen levels could be set with the mode button on the steering wheel. I also wish that when in cruise control mode and in the B position that when cruise is canceled and the brake hasn't been pressed that regen ramps up slowly to make the transition off of cruise control smoother.

Re: The origin of the 'B' mode setting.

Posted: Mon Jan 30, 2017 8:24 pm
by cmiller82
JejuSoul wrote:-
The only way to save energy is to not use regen or brakes at all. (on the Soul EV the only way to get no regen is by putting the gear-stick into 'N'). I strongly recommend NOT to use this method on the current Soul EV because of the badly designed gear-stick. If you go into 'P' by mistake you will destroy the transmission.


Are you aware that the shifter will move up from B to N without pressing the button on the shifter? You can just press up and end up in neutral. The button is required to move to reverse and park. I often change between N D and B when traveling in very hilly areas.

Re: The origin of the 'B' mode setting.

Posted: Wed Feb 01, 2017 6:51 pm
by JejuSoul
cmiller82 wrote:Are you aware that the shifter will move up from B to N without pressing the button on the shifter? You can just press up and end up in neutral. ...
Yes, I am aware. But pushing the button can become a habit.
To go back from D to B you do need to push the button.
And you always push the button when starting, stopping and going into R.

I have never accidentally pushed into P while driving. Someone else did.
But, I did accidentally push into R one time. Nothing bad, happened! There was no one close behind me.
That was why I don't use N while driving, and recommend against it.