How does transition to Hybrid work when EV Battery runs out on highway

the thing to remember is that the prime can continue to travel at 84 mph without use of the ICE. This gives the ice plenty of time to warm up prior to being needed (unless you're planning running up to 85 mph in cold temps right from the get-go). The portion of the battery set aside for HV usage is still plenty to continue to propel the car for the amount of time necessary to get the oil moving nicely.

 

I think it was suggested in another thread that this could be due to different accelerator pedal mapping in HV mode vs. EV, and not an actual decrease in available power

In automatic switchover to HV, but what when manually switching to HV? Probably no difference, I would think they both handle the switchover identically since in both cases there should be plenty of charge available for engine warmup.

However what about EV Auto? In concept it turns on ICE because you are demanding more power than the electric motor can provide alone. But that's an instantaneous demand that the computer cannot predict. My guess is that EV Auto is basically unavailable for the first half minute or so while ICE warms up (longer in really cold weather). Which could explain some anecdotal reports that EV Auto doesn't seem to make a difference. Maybe that is true when ICE is cold.

So as we know the switchover occurs while there is still plenty of charge left to power the car during warmup, and we assume (hope) that the HSD computer is smart enough to use only battery power during warmup, unless it can safely draw a little bit of power from ICE during warmup depending on the current engine temperature.

However I don't think anyone answered your scenario where you put a heavy demand on the engine at that moment, like flooring it to accelerate and pass someone while climbing a hill. My guess is that it is similar to the EV Auto scenario that I mentioned, you simply won't have as much power as you would if the engine was warmed up. However not knowing that for certain, in theory it could attempt to provide the requested power even with a cold engine, thus putting some wear on the engine, but hopefully not too much since the electric motor is assisting also. And that little bit of wear might not be a big deal if it's somewhat rare, unless this happened daily as part of a commute. So I guess to be safe don't floor it when the engine is cold. But that could turn out to be overcaution if in fact the HSD computer is 100% infallible in all situations.

 

The engine is needed for cabin heat, anyway. That is too cold for the heat pump to operate well.

The questions raised in this thread are interesting. I feel the engine when it takes over--there is a small bump when the engine takes over running fast & uphill. I cannot feel it warming up. In any case, Toyota's system is smarter than I am. I like the way it works. When I know that I'm running on battery and coming to a place where I'll need max acceleration, I switch to HV a short time before I get there to get some easy warm up. Then I get both the engine and the batteries working together. After that I switch to EV or EV Auto as I anticipate I'll need. That works for me.

 

I was wondering if you meant block heater or Prime, lol. Sober second thought, I think you mean Prime, and yeah, they might be off-the-table here.

 

What is really a big advantage of the Prime is the charge can be saved for the return trip. So I go to the Gym in eco mode, get 70-80mpg downhill. on coming back home the car is in eco/ev ( I have no choice in the matter, I cannot get the car into pure ev) eco/ev produces phenomenal mpg, up 2000 feet with 200 mpg plus.
I’m confused, but Not complaining

 

eco/ev? do you mean ev/auto?