B position resurfaced

I have not experienced this. Down the big grades on I-70 in Colorado, EV mode in B, running speed limit, normal interior vehicle temps. I recall about 50% battery regenerated and the engine did not start.

My Hybrid Reporter files show a maximum allowed charge limit of 40 KW (never more than that). But, there are some displays where the max charge rate varies widely less than that amount.

 

Just to keep things clear for other readers who find the thread, I would want to emphasize that pretty much everywhere in the above, "engine comes on" means only "engine's moving parts are being moved, serving as mechanical resistance".

The OP's question about whether the engine is in fact on and using fuel in B mode is the part you got to later:

... where it comes down to whatever other rules in the control logic might require it to start and run briefly or be at a certain temperature under certain circumstances.

 

I've seen the engine provide resistance in B mode driving from the Eisenhower tunnel to Silverthorne, which I think is about 12 miles at probably 6-7% grade and a speed limit around 65mph. And from Freemont Pass to Copper which is a few miles of 7% grade at 65mph.

 

I didn't start using the term ICE until I joined PC, and it was for this very same reason. In the mechanical world, "motor" and "engine" are often used to describe the same thing. However, an electric motor is never called an "engine". It makes sense to go to the trouble of describing these two different components by using their formal names - if only to avoid confusion: The electric version being "motor-generator" or "mg" and the mechanical version being "internal combustion engine" or "ICE".

 

I'm headed out that way on I-70 next month. I'll run Hybrid Assistant and grab some data.

 

Those are some interesting observations. In my case, if I'm switching into HV mode at the beginning of a trip ( so far that is only when I'm driving beyond EV range or in the winter when cabin heat is needed ) and I have enough time, I like to wait for the warmup cycle to complete and the ICE/engine to switch off before I shift into D rive. I've always wondered how much gas the warmup cycle uses at various
ambient temps.
I'm assuming that when you mention above

that is going down the long 10 mile descent as well. At least that is the way I'm reading it, because my experience with the 14 PiP's 999.9 mpg meter was much different while on a flat or mildly descending road. Closer to from 999.9 mpg to 300 mpg in a very short time, 30 second to a minute if I recall correctly.
Again, thanks for sharing your observations and hopefully demystifying some of the confusion attributed to B mode.

 

I've only watched the gas usage on shorter descents. It uses a tiny bit of gas to get the engine started, then it stops until the bottom of the hill. That is in mild weather. I don't think I can get to any long descents in EV mode, so a measurement wouldn't be relevant since the engine would already be warm.

There's no need to wait for it to warm up. Most of the power will come from the electric motors until the engine is warmed up.

 

Yes, it is not necessary to wait for the ICE/engine to stop during warmup mode, before driving. Most miss the point of even trying this as an experiment.

 

A bit more detail: While warming up, the system will primarily use the electric motor to move the car, even if that means temporarily pulling the state of charge of the battery a little lower than normal. This "loan" will be "repaid" after warmup is complete.