Outside temp kicks engine on?

i think it might be a combination of factors, but if all you did is hit the start button and it fired up, that's surprising at 32 degrees. i run on pure ev all winter long down into the teens, and only have the ice come on at one particular spot in my commute if i'm not careful.

 

There are (at least) two outside air temperature factors:

1) There is the one where the climate control system is calling for cabin heat, about 59 F.

2) And there is another, much lower, temperature, at which the ICE will come on even if no cabin heat is being asked for.

3) And possibly there is battery low temperature trigger. (Unless that is actually #2.)

Only the Toyota engineers know. There is apparently no publicly disclosed information about this.

 

he didn't have cc on, so it must be #2 and 3. but 32 degrees ambient is way too high.

 

I understand the difference.
Since the OP's profile say's 2004 Prius, I assumed he wasn't talking about a pip.

 

Keep in mind that the machine,- has no idea whether the trip is going to be short.
So you can sit in the drivers seat and "know" the trip could easily be accomplished in EV mode, but The Prius doesn't know this.

The Prius is going to make operating decisions based on things it IS capable of knowing. Such as Battery Charge level or engine temperature.

I don't think anything too much more complicated than.....when the engine is cold it will run is happening here.

 

We did not misunderstand your question. Bisco answered your question on post 2. This thread continued on only because we don't think temperature is what caused the ICE to turn on in your description.

 

Here's a video driving my Prius PHV at -2°F without the heater... electric-only for 9 miles, no engine:

 

Here's that same route at -10°F while filming output from the Torque app:

 

Yes, extreme cold outside while parked at work will cause that.

Those 2 videos show me on my commute to work, after having left an insulated but unheated garage. That's just barely enough to keep the battery warm'ish overnight. Sitting outside in the exposed parking lot all day in sub-zero F temps, the engine will start at about 25 mph. So, on the commute to home, I lose EV right away. The system still draws from the pack, but it's in the form of EV-BOOST instead.

Sorry, I don't know the specific combination of outside & battery temperatures to trigger that. But in such cold, I want the heater running anyway.

 

charging is a factor. do you charge outside greg?

 

That's the key. There is the need for "housekeeping" events, where emissions are collected for cleansing at a later time with the hope of more heat being available then. We have no idea what the criteria is for that to happen. But the engine running unexpectedly or at a higher RPM than usual would be an indicator of that.

We don't know that either... again, it's emission control stuff. The engine will sometimes run a full warm-up cycle even when the coolant temperature is at 165°F. I notice that after a hard-acceleration following a long drive in EV.

 

yep. we'll never know exactly what's going on. there are plenty of threads here where we discussed it, but never came to any conclusions.

 

Sorry, I looked at your ORIGINAL profile which only stated 2004 Prius.- Bout time you updated that.
I'll excuse myself from further commentary as I don't own a PiP.
Good Luck finding your answer.

 

Did you use the timer to finish charge close to your departure in this day when the ICE turned on?
Could be a very cold night and charging is warming the battery.

 

The act of charging a battery warms it up. If you set the timer to finish charging right before you start the car, then the battery will already be warm instead of cold. You also get the added benefit of residual heat in the cabin. I don't think warming the engine warms the battery unless you call for cabin heat. However, if the battery is cold, the may engine comes on. I'm not sure why because same as the engine, the battery will warm up as you start discharging it.