Regenerative Braking - D or B ?

You don't need to alternate. Just press the gas pedal enough to reduce the amount of B-mode regen/engine braking to the desired level.

There is no need or advantage to taking your foot off the gas pedal while in B-mode.

 

So, unlike in D mode where you press the brake pedal to augment the Regen until the brakes have to kick in, in B mode, you (lightly) press the gas pedal to reduce the Regen so you keep moving at the speed you want. That's it?

 

Yes.

Initially, some drivers find it a bit disconcerting when they discover themselves in this narrow set of circumstances where pressing the pedal down a bit causes the engine to spin slower, not faster. But it is a narrow range, and easy to get accustomed to.

 

Sounds similar to the one pedal driving in Tesla, except there it can bring the vehicle to a stop. Still, I'll give this a try as I very much like that one pedal driving.

 

I find D has quite a bit of regen, just about perfect. The brakes need to be used a little, as when coming to a stop can hear them the last few feet. Otherwise discs get rusty. Not using at all the brakes, not good at all.

 

I haven't yet driven any Tesla, but suspect that the Prius version is significantly milder than the Tesla one-pedal driving.

Note that used in this mode on flat roads, the Prius MPG will likely decrease. The Tesla version doesn't waste any of its electric braking energy as ICE compression braking, or as ICE idling while stopped, as the Prius will. B-mode will prevent ICE auto-shutoff, shorting circuiting one of its fuel saving measures.

 

When I drove a Model S around 2014 - 15 , regen was adjustable. I believe I've seen youtubes of other models witht eh same adjustable regen in the settings on screen. And yes, it's can be adjusted way beyond what B mode give us in the prius. I remember before I learned how much braking I could get in B I used to hold the joystick in the B position dreaming I could get more regen braking that the prius allowed.

 

In newer Tesla, you can't adjust it anymore. It's always full Regen when you let go the accelerator. I don't know why they removed it. Older vehicle still have the option for Low Regen but not newer one.

 

I understand the concept, but doesn't that use gas necessarily? If you're able to not press the gas pedal at all, wouldn't that be an advantage?

 

I guess it depends, just like when you start to press the brake pedal, you don't actually apply the physical brake, you start by using more and more Regen, until it can't Regen at any faster rate. I guess the same applies to the accelerator in B Mode. Between full throttle off and engine kicking in, there is a region where Regen will be used at different level.

 

@GeoJ you have to remember that B while in EV is much different than B in HV or how it work in the regular prius. It's very confusing to new Prime owners trying to understand how B is working for them when they read how B works in the regular prius, which is very much like (if not identical to ) how B works in the Prime while in HV mode. Hope this helps a little.

 

When using engine compression braking in B-mode (or also D-mode), fuel is completely cut off. None is burned. This is true of most modern non-hybrid engines too, ever since 'DFCO' (deceleration fuel cut-off) was added decades ago.

Now, once you press the pedal far enough to get propulsive power, then it will burn either battery charge or gasoline. Or when you come to a full stop in B-mode -- at least with the older generation non-plug-ins -- the engine will stay on in Idle, which does burn some gas.

 

I watched one of my long time subscribed Tesla youtube channels Out of Spec Motoring do a review of the bz4x and Kyle mentioned near the end that the bz wouldn't stop without using the brake pedal. Granted it was his first time driving the car, but later watching the Alex on Auto review of the lower trim bz he mentioned there was a one pedal button on the dash, but did not include a demonstartion of how it works while he was driving the car or even show the button while filming the dash segment.

Thanks for mentioning that Tesla has discontinued the adjustable regen feature they used to provide. When I turned regen all the way up in the Model S, it was a significantly different driving experience than when regen was set more to the middle of it's range..

 

Would you say the Regen in B mode is similar to what low Regen on the Model S was?