The most misunderstood aspect of the Toyota hybrid synergy drive system

My 2024 is much quieter and smoother in spinning up for light engine braking than were my 2010 and 2012, despite having a larger engine. I need the tach to be certain.

That is so 20th Century. Those of us quoting engine-braking RPMs here for various operating conditions, have used the 21st Century method, which as Chap noted, was available in all U.S.-market cars a handful of years before the 21st Century actually arrived.

Most people don't have to prove themself to themself.

 

Ah, now THAT's an interesting nugget.

I had hypothesised that maybe B did something that D could not, in that engine braking strength was determined by the D/B selection.

In normal use, we know regen could substitute for brake action on a pedal press, and regen or engine braking could subsitute for simulated transmission drag.

What I didn't know was whether engine braking could substitute for brake action like regen can. Maybe it only engine braked up to the transmission setting, and the brake pedal could only affect brake pads if regen was unavailable, so B was significant to give you more engine braking, and could help your brake pads.

But if the engine revs up to give more engine drag when you press the brake pedal in D, then that suggests the whole "braking+drag" system is fully integrated, and it seems B really doesn't do anything D can't. (Apart from the legal safety aspect of "what if something happens to the driver and they release the pedals").

 

Couple of thoughts:

@Paul Gregory has a plug-in, which may change things.

I’m puzzled about The Car Care Nut’s emphatic assertion, that shifting to B gear invokes full regen.

 

I'm sure plug-in does change things, but it's largely a knock-on effect. The plug-in has far more regen ability generally, and is far less likely to be anywhere near real top-of-SoC. So given the same basic control algorithm of "start engine braking when insufficient regen available", the chances of either D or B needing to start engine braking to satisfy a drag requirement is far less.

On an earlier generation, B may well have almost always required engine braking to meet the drag requirement - or B may been even beyond full regen and always required it (back in Japanese G1?). Thus clearly associating B with engine braking. But B drag is now firmly less than full regen in a plug-in, so the chance of it starting engine braking is slim, not much higher than D. The main thing associated with engine braking will be a massive downhill, not which drag you're asking for.

 

i'm puzzled about many things the nut says