B Mode

[moggio53]

This may sound a bit daft, but here goes. My wife just puts the car in D, and off she potters. I always use B since I believe this provides regen and the electric motors slow the car down and not the brakes - who's right and does it really matter

[MikeSh]

20 minutes ago, moggio53 said:

since I believe this provides regen and the electric motors slow the car down and not the brakes

Why don't you don't think this happens in D.

(Since Toyota built these for 'average' people then wouldn't they make regen the most obvious and easily selected option?)

[Mojo1010]

B mode is for engine braking design to use when descending a steep hill. D is driving. 

[CPN]

45 minutes ago, moggio53 said:

This may sound a bit daft, but here goes. My wife just puts the car in D, and off she potters. I always use B since I believe this provides regen and the electric motors slow the car down and not the brakes - who's right and does it really matter

She's right and you are wrong. "B" is to provide additional engine braking when you are descending a steep and long hill.

Also, her MPG figures will be better than yours since driving constantly in "B" mode will use more fuel.

[moggio53]

2 minutes ago, CPN said:

She's right and you are wrong. "B" is to provide additional engine braking when you are descending a steep and long hill.

Also, her MPG figures will be better than yours since driving constantly in "B" mode will use more fuel.

Thanks guys - thats cleared that one up!!

[Cyker]

It's a bit weird as the B-mode behaviour has changed slightly in the different generations of HSD (Hybrid Synergy Drive, the 'official' name of the Toyota hybrid system).

The older ones *would* go maximum-regen in B-mode, as well as engine-brake, which could under certain circumstances return better mpg, and is partly why this incorrect 'fact' of B-mode being for regen keeps getting repeated by a lot of ignorant car journalists (The same ones that think it has a belts and cones gearbox  ).

However, the newer HSDs like in the Yaris, Corolla and probably RAV4 do fairly minimal regen, in both D and B-mode, when you lift off the accelerator - one block (out of 3) of regen shown on the power. This is theoretically better for economy as you can coast a lot further when lifting off, and the only way to get the max regen is by using the brake pedal - That lets you get up to the full 3 blocks of regen.

I'm not sure why they changed the behaviour in the newer HSDs, as it made sense to me to max-regen in B-mode, but now it stays at the same level of regen as D-mode, and instead dumps the rest of the energy by acting as a very inefficient air-pump with some fairly aggressive engine braking.

The B-mode is actually quite pointless though - It's designed to save your brakes on e.g. a long descent, but if you just use the brake pedal, it'll hardly use the brakes and instead use maximum regen and charge up the Battery, but when the battery's full and you continue to brake, it switches to engine braking anyway!

 

[TonyHSD]

I don’t think the older ones go full regenerative braking in B.
Gen 3 for example when in B and going downhill and lift off the accelerator the regen goes down just a bit and if the downhill is steep you have to use the brakes otherwise the car will start gaining speed again. 
The cruise control can use so much more regen braking than B mode. I am often using the CC when going downhill and I am watching it on the dashboard the power meter hand can go halfway where in B mode only 1/4 max. 
D is the only mode for driving and B only in ultra rare occasions. 
 

[BlueMike1972]

Indeed, a lot of the You Tube reviewers were getting this wrong too, merrily stating that B was for extra regen, when it is nothing of the sort.

[Corolly Poly]

I also wonder why my 2.0 engine does not have a 'B' mode. Why is it different to the 1.8L?

[hind]

Maybe Toyota integrated the "B" logic into "D"? The 2.0 (M20A-FXS) is a newer engine than the 1.8 one (2ZR-FXE) so the drivetrain might be changed too. 

[jthspace]

As mention above by @Cyker the B mode gives greater engine braking rather than regen.  On a twisty country road I may select B mode to give engine braking rather than using the brakes on every corner.  

In B mode things like cruise control et al don't work on the Yaris.

[forkingabout]

1 hour ago, Corolly Poly said:

I also wonder why my 2.0 engine does not have a 'B' mode. Why is it different to the 1.8L?

They normally have a S mode instead - info below for first gen C-HR 2 litre hybrid.

It's more economical to leave the shift lever in D.

I've used S mode once back in 2022 to try it out.

Have a read of your owners manual.

 

 

[trashman1965]

On the 2.0 corolla, you can use the flappy paddles to "downshift", even when in D. That has the same effect as B mode.

Again, for general driving, it's not needed. Leave it in D and let the car work out the best thing.

[TonyHSD]

B mode does indeed add extra regen in direct comparison to driving in D and lift off the accelerator pedal. 

D will continue to coast with minimal regeneration where  
B will start to slow down quickly and add more regeneration to the system. 

Every single slow down no matter if in D or B , with CC on or off , will add more energy into the system. 
Everything will be displayed on your power meter. 
In 2.0 and 2.5 engines the transmission is only slightly beefier but works exactly same principle, however B mode is replaced by pre set fake gears ratios which add extra regenerative braking and engine braking depending on Battery charge and road conditions. 

Just drive in D and see owners manual for better understanding of the car operation. 👌

 

[Mojo1010]

Think OP just need to ask his wife for better understanding of driving in general 🙃

[coreye9090]

2 minutes ago, Mojo1010 said:

Think OP just need to ask his wife for better understanding of driving in general 🙃

isn't it the other half who drives in "B" and not the wife???🙄😅

[Paul john]

3 hours ago, forkingabout said:

They normally have a S mode instead - info below for first gen C-HR 2 litre hybrid.

It's more economical to leave the shift lever in D.

I've used S mode once back in 2022 to try it out.

Have a read of your owners manual.

 

 

Isnt that Sport mode not B mode?

[forkingabout]

1 minute ago, Paul john said:

Isnt that Sport mode not B mode?

Sport mode is selected via the steering wheel buttons. Sport, Normal & Eco modes.

S mode is completely separate & on the shift lever instead of B mode.

[MikeSh]

28 minutes ago, TonyHSD said:

D will continue to coast with minimal regeneration where

In my experience electric/hybrid cars have a default set up that gives similar results to a 'normal' (automatic) car - a little bit of deceleration with neither pedal pressed - so people don't have to change driving styles when crossing over.

There are exceptions and some can be adjusted. I test drove a BMW i5 years ago which was set up for one pedal driving (don't know if that was default), so lifting your foot off the gas pedal sent you into the windscreen. It wasn't something I would live with having another car very different.

[forkingabout]

1 hour ago, Paul john said:

Isnt that Sport mode not B mode?

Sport mode is here.

 

S mode is here.

[dash]

Am I on the Corolla, CHR or Yaris forum? 🤣

[Rhymes with Paris]

5 minutes ago, dash said:

Am I on the Corolla, CHR or Yaris forum? 🤣

I think it's called forum cross pollination.

[trashman1965]

Meh let's ask a mod to move it to the GR Yaris forum as that's where most Yaris posts start lately 😂😂

[exim]

Must have been a sluggish ride in B all the time mate.

[Paul john]

3 hours ago, forkingabout said:

Sport mode is here.

 

S mode is here.

Ah. So its a variant of an Auto gearbox “speed shift”