Switching from EV to Hybrid in Cold Weather

Welcome to PC. No need to worry. This is a very smart car, it decides when it's time to change over to HV, or you can switch to HV any time if you so desire. AFAIK, even pure gasoline cars do not require an engine warm up.

 

congrats and welcome!
probably fine, but i like to do it ahead of time when there won't be much engine needed, avoiding a start at high speed, uphill, or hard acceleration.

you can't always know, but usually can judge that you won't have enough ev to complete your trip when there's only a mile or two left.

all the best with your new prime!

 

When the engine first comes on, the car continues to run on electricity until the engine has warmed enough, ~45 seconds, for the catalytic converter to start working. In effect the engine is idle and then it takes over the load. You'll see this as a 1-3% decrease in battery SOC until it takes on the load. Then the car will add enough charge to come close to the original SOC.

If you have a choice, put the car in hybrid mode when beginning a descent. This will ensure the car does not see a high power requirement before the catalytic converter is running. It minimizes the initial 'warm-up' fuel burn.

Bob Wilson

 

Not sure where you came across that. It's a misconception.

5 winters in Minnesota with my Prius PHV confirmed it was a non-issue. As mentioned, the system goes out of its way to prevent stress on the engine while warm-up is taking place, even if you are accelerating onto a highway at the time... which I did routinely, living just 3 blocks from one on my commute. Here's a real-world example the other direction, with the engine firing up while on the highway:

Last year was my first winter in Minnesota with Prius Prime. This video shows the warm-up process taking place, triggered while driving in conditions below the heat-pump threshold... complete with ODB-II data. So, it's a sweet example of what you want to know more detail about:

 

Gotta love how you can get 50+mpg with a stone cold engine in a PiP or a Prime. Well, really any Prius. Granted, you have to put that back into the battery when the engine warms up, but it's still amazing. Thanks for the vids, @john1701a.