When and Why should we use B gears?

[Grigou]

Certainly an interesting picture anko, but there is no need of measurement to feel the difference between braking in B0 an braking in B5.

Thanks. But now you are probably talking about 'coasting' in B0 versus B5.

No I wasn't talking about coasting, I was talking about braking with the pedal.

That difference is imho undebated, but not so much of interest.

So you think that I could loose my time talking about something not so much interesting ? :lol:

Question is (more or less): does B0 plus brake pedal equal B5. I think that is rather difficult to 'feel', and this is why some may think they are the same from a regen perspective.

For me (and driving MY car, at least) it is not difficult to feel at all. It's even an evidence. And the MMCS clearly shows the difference, too

I think that every Bx gives a different power of regen while breaking (with the pedal ). For me there is a difference between B2, B3, B4 and B5, too.

But I can't prove it. I'm just sure of that, because the odometer shows 27000 km and I've had all my time to make some tests since I bought the car, especially in the Alps, where I drive quite often

 

[anko]

So you think that I could loose my time talking about something not so much interesting ? :lol:

Fortunately, you were talking about something else from what I thought :mrgreen:

But I must say, I have never felt the friction brakes being applied. So without looking at regen numbers, I would not be able to tell the difference between B levels. So, either you are better than I am, or my car is better than yours is

 

[Grigou]

So, either you are better than I am, or my car is better than yours is

I let you to choose ! :mrgreen:

Anyway, my advice is to look at the regen numbers (or better : record them with your devices), and I'm sure that you will be finally convinced ... excepting if your car is better than mine ! :lol: :lol: :lol:

 

[SolarBoy]

On leaving the motorway slip road I had B5 dialled up, without changing pressure on the brake pedal dialled it to B0.

Results were:
- Sounds of mechanical brakes being applied
- Reduction in regeneration from fully deflected down, to just below the scale.
- Reduction in the deceleration of the vehicle

This was done with a battery at 1/3rd of charge.

All unscientific but very surprising.

 

[anko]

To me, the surprising thing is that you can hear the mechanical brakes being applied :mrgreen: . Apart from that, all of these effects were to be expected IMHO, although maybe not at the same time ....

I have always argued that the maximum regen capacity in B5 is much higher then it is in B0, with as a result that, with similar driving style, less energy is regained and more friction braking is going on.

 

[SolarBoy]

To me, the surprising thing is that you can hear the mechanical brakes being applied :mrgreen: . Apart from that, all of these effects were to be expected IMHO, although maybe not at the same time ....

I have always argued that the maximum regen capacity in B5 is much higher then it is in B0, with as a result that, with similar driving style, less energy is regained and more friction braking is going on.

Car doesn't do many miles, only 2k in 7 months, so when the brakes go on the rust comes off!

 

[anko]

Car doesn't do many miles, only 2k in 7 months, so when the brakes go on the rust comes off!

:lol:

 

[Steel188]

SolarBoy, you and I got our cars at about the same time, but mine now has well over 18,000 miles on the clock. Yet I too can feel the difference between braking in B5 and B0, mind you, I doubt it makes any difference to available battery power beyond a few extra yards, which over an average day really isn't worth the effort! (Other opinions are available!)

 

[vs2]

After driving in all conditions and modes I now drive around in the area I live in in B3. Why? Because with the hills and gradients and to keep on the speed limit B3 works perfectly and on most hills it will stay at around 50kmh without touching the gas or brake pedal. On the motorway I use D (B2) and on long motorway hills I will use up to B4 and sometimes B5. With stop and go traffic I find B4 works well.

Edit: With normal CC on (not ACC) you can leave in the B modes whereas ACC goes back to B2 only. This is good as if you leave in B3-4 using CC it will automatically slow you down on hills and maintain set speed but if you use B0-1-2 you will keep gaining speed on hills.

 

[SolarBoy]

SolarBoy, you and I got our cars at about the same time, but mine now has well over 18,000 miles on the clock. Yet I too can feel the difference between braking in B5 and B0, mind you, I doubt it makes any difference to available battery power beyond a few extra yards, which over an average day really isn't worth the effort! (Other opinions are available!)

My apologies, I have done just over 2,200 miles :lol:

Had to B0 on the school run today and nurse it gently battery meter said 6 miles battery, motorway to school at 55mph, then 30mph on an A-Road to return. Not sure why it went down to 6 miles as had only done 10 since a full charge. Guess it doesn't like lots of short journeys. Last mile was done with 'zero' battery which to be honest indicates yet again to me that the battery meter is complete useless. Paddles are fun in stop/start situations and make driving easier.

 

[greendwarf]

Well, since we have had a 20mph limit in most of Sarf London. I've found I can coast in B0 for a lot of journeys and so, without the need to maintain a higher speed or accelerate as much, nor even brake so frequently, my electric usage IS significantly lower - very rarely going below half SoC each day before topping up overnight. :mrgreen:

One interesting insight into the workings of the guessometer last weekend. I drove to Southend - EV in the City until putting into Save for the higher speed dual carriageway (50mph) and back to EV within Southend. When I stopped for a free re-charge in the town centre I had 18 miles range left. When I unplugged 3 hours later the full charge offered me a 36 mile range - i.e. I must had exactly half battery left so the guessometer doubled the range. Of course, within a few miles it had dropped to a lower, more realistic figure.

But to go back to Solarboy's experience - 55mph in EV, irrespective of the B setting, will cane the charge level rapidly, unless there are significant declines to coast down.

 

[anko]

Guess it Last mile was done with 'zero' battery which to be honest indicates yet again to me that the battery meter is complete useless.

At higher steeds, empty means 30.5% SOC. At lower speed empty means 26% SOC. Not knowing at which speed the final miles will be driven, the instrument assumes the worst. So, the meter may show 0, even when there is some SOC available for driving at low speed. How does this make it completely useless? Or, to put it differently, what would you have expected?

 

[SolarBoy]

Guess it Last mile was done with 'zero' battery which to be honest indicates yet again to me that the battery meter is complete useless.

At higher steeds, empty means 30.5% SOC. At lower speed empty means 26% SOC. Not knowing at which speed the final miles will be driven, the instrument assumes the worst. So, the meter may show 0, even when there is some SOC available for driving at low speed. How does this make it completely useless? Or, to put it differently, what would you have expected?

A percentage indicator eg, 2% remaining, would be better. Though I suppose actual battery remaining indicator is also part of the guess-o-meter contraption

My journeys are either really short, or 220 miles/5.5 hours in terrible traffic and the shortcomings and logical choices the engineers could have made haven't been implemented. For example, the SatNav that has the built in traffic awareness ought to be tied into the Charge/Save buttons to make the best choices on how and when to use the battery.

 

[anko]

A percentage indicator eg, 2% remaining, would be better.

Funny, I have that (Although it has never gone below 18%. And will never ever go below 13% as the car will come to a halt when that happens.)

But to be useful, the %-age requires a lot of understanding of the way the car operates and a lot of interpretation, I think much more that the average owner would care for. I can image Mitsu would say they purposely choose not to bother the owners with such details, and I think this time I would agree with them :mrgreen:

 

[rjpfff]

I think this is more an opinion than it is a proven fact . Please see below picture. It shows two decelerations (ignore the bit in the middle).

First one is using the brake pedal (blue trace depicts actual pressure in brake lines that deploy the friction brakes), while driving in B5.
Second one is using the brake pedal, while driving in B0.

The grey trace (speed) shows the first and third deceleration are quite comparable.
The pink trace shows how much wH (x10) is regened back into the battery per km.
The white trace shows how much kW is being fed back into the battery.
Green and red show how much braking force (torque) is applied by the e-motors.

Altogether, I think B5 must have a positive effect on energy recovery site, unless one manages to never use the friction brakes.

My 2020 Corolla is the first time I've seen an automatic with this B, downshifting gear. Exactly how/when is the best way to use it?


I've used it only when going down big declines on the interstate and going over 50 miles an hour. But are there other uses. Should I do it when going 30 in the city and braking? This seems particularly potentially useful in the Bay area where I live as it has so many hills.

So....anyone want to give advice for how often/how to use the B gear?

 

[kpetrov]

B in your conventional 2020 Corolla with automatic transmission is very different to B in PHEV.

If you ask from efficiency point of view... best if you don't brake at all, second best if you use regenerative braking B, as slowly as possible better it is. Worst frictional brake.

Even if you don't use B settings mode the vehicle will use regenerative braking before mechanical when pressing on brake pedal, but then it depends how fast you are braking and how hard pressing on the brake... before the mechanical brake overtake regenerative one.