Driving in "B" Mode Regularly

I thought "B" was exclusively engine breaking but based on wording from the manual it may be that while in EV mode it just ups the Regen. "...or strong breaking..."

I'll have to see and maybe compare the noise and feel in EV vs. HV modes to see if it seems like the engine is turning in both or just the MG in EV mode.

Posted via the PriusChat mobile app.

 

I've heard B is somewhat different in plug-in version??

Other'n that, I would reserve B for mountain descents.

 

cruise control works even better on descents. If the result is no speed change, the brake lights do not turn on in cruise, and you get all the re-gen.

 

Ill try it next week, my AM commute is mostly, if not all, EV. I have a good idea of what range I should expect in EV only, so I can compare it to B mode EV. I'll let you know on Friday.

 

Taking your foot off the brake pedal in D mode and gently applying the brakes is exactly equivalent to B mode, at least in EV mode. No friction braking at all. In HV mode, B can trigger engine braking, which is just tossing the energy out the window. And I cannot see how B mode would be so great in city driving, since there are losses when doing regeneration, so taking your foot off the throttle would result in more losses over the lighter regeneration in D mode; it would be like lightly applying the brake every time you took your foot off the throttle, whether you needed to slow down or not. Yes, there is energy being put into the battery by regeneration, but you don't get out as much as you put it.

 

Experiments never (almost never) hurt anyone, besides they're fun.

 

Most plug ins have a way of increasing the amount of regen braking. Some have deceleration rates high enough that the brake lights are triggered, and may even bring the car to a complete stop.

The advantage is in not having to move your from the accelerator to the brake pedal in order to start bringing the car to a stop. In city conditions, the time saved could be the difference between being in a crash or not. Some people just prefer one pedal driving too.

Personally, I'd have to see if B mode effected the ability of getting into a glide, and if its regen braking came on too fast before deciding on using it normally.

 

My driving using "B" in EV mode does not prevent me from gliding (coasting) to eliminate/minimize re-gen. It works exactly same as in "D" mode. Actually the only inconvenience of "B" mode is that DRCC is disabled.
I found DRCC very convenient in Stop&go traffic with prolonged stops. If there is a stopped vehicle in front engaging DRCC ( lever up = resume) will allow me to take my foot off the brake which is very comfortable (at least for me)

just my 5 cents

cheers

Kris

 

I downloaded a pdf of the Prius Prime Owner's Manual, and I'm not seeing any of your points. Again, I would just leave it in D, reserve B mode for mountain descents.

 

That chart was likely just cut & pasted from the Prius manual.
While in a Prime's EV mode, nobody has reported the system spinning up the ICE when B is engaged. Without that spinning, increased regen becomes the only possible option for the car to increase the selected gear's braking ability.

 

Ok I gotcha: B might behave differently in the Prime, that I have heard here. And my snapshot from the Prime manual, may well just be what Toyota cut-and-paste from the regular Prius manual when creating the Prime manual.

A lot of the uncertainty and debate can be laid on Toyo's doorstop, their instruction is extremely terse. Maybe they don't know how and when to use it either? Or at least at the manual writing level.

 

In EV mode, B position is same as lightly pressing the brake pedal in D position - same regeneration for the required deceleration (and no friction brake).
I think that with the Prime - B position does not activate brake lights (worth checking) and if so it is a hazard in stop-and-go driving.
Using B position constantly in stop-and-go may develop to "less efficient" driving habit of late letting off the throttle pedal.
I am using B (with my PiP) only when going down a mountain where B suppresses acceleration.

I don't think so, AFAIK the liftback manual does not have the statement "...or strong braking..." which is unique to the plug-ins being in EV mode.

 

My scenario is such. Normal D mode but downhill after a cold start and full recharge. I've had the ICE spin up several times now. The EV mode WILL turn off automatically, full battery mind you. ( the indicator shifts from EV to empty car symbol) To burn off the excess charge coming in from braking down the long hill. Have no choice as car will just pickup too much speed.

I'll experiment with B next time but it makes no sense that it won't spin up anyway.

 

Is it practical for you to partial charge and letting the long downhill do the rest?

 

If the battery is full, then engine braking is the only choice. And when the engine is spun for any purpose, it has to go through its warmup cycle.

 

Not really...

That's been my fear, waste of energy. I guess my ECO score is gonna get even worse I'm better off just stepping on gas more to start to lower the battery a bit more.

But anyway, back to topic, I'll let others test the B mode in EV city (flats). I suspect though that there will be less glide taking place.

 

No brake lights being a hazard determination requires knowing the current deceleration rate. Other plug ins that regen braking rate disconnected from the brake pedal, have the brake lights activate based upon what that rate is. The rate at which the brake light goes from off to on could be dictated by regulation.

The braking of B 'gear' is mild. It is not strong enough that drivers behind the car need additional warning of its slowing.

 

What about the other points raised in the post you elected to quote in its entirety?