whats the best way to use gas engine in cold weather?

Turn off the ECO settings, put the blower on driver priority, then turn the temperature up to HI. That will use up electricity faster, but you'll get nice heat.

To use the engine for the sake of exercising it and not letting gas get too old, drive using Charge-Mode.

 

can't you just select HV mode?

 

For a temperature above 32F, if you need it, using an electric-only heat pump works great without firing the engine. For temperature below 32F heat pump becomes inefficient and at around 14F or below, it will not function as a heater by itself and the engine comes on automatically. As others pointed out, just switching to HV is all you need to turn on the engine. You don't have to use the front defroster if you don't need to.

Since I don't usually use heat down to 20sF, during winter commute, I usually switch the car to HV as soon as I start the car for the morning commute and use the engine for the heat and HV for the travel usually in single digit and 10s temperature preserving as much EV range as possible. Then for my commute back home in the afternoon with moderate temp (upper 20s to sometimes low 30s), I use the EV to come home mostly without heat but if needed then with just using heat pump.

Generally speaking, if the trip is longer than the EV range left in the car and the temperature is below 32F, I usually start the car and switch to HV mode immediately and try to use HV mode and EV mode mixed keeping the engine warm for the entire trip so that it will not have to go through the warm-up cycle more than once. With this approach, even during winter, I am able to achieve very good EV efficiency.

 

Wow, don’t use the heat with temps in the 20s - you are stronger than I. I get so cold sometimes I can’t think in the 20 degree mornings when it’s still dark out. I use the heated seat and remote start and still have my coat on.. lol

 

I do similar to what Salamander King does. This is my first winter with the Prime and weather so far hasn't gotten too far below 0C or 32F.

How does the Prime do when it is stupid cold... Let's say -30C or -22F?

 

See for yourself, at -8°F. This is one of my commutes.

 

So, what is your priority? To warm up the cabin or to fire up the engine or conserve the battery SoC or some combination of those three? If you need to fire up the engine for some reason, there are a few of those occasions such as wanting to get rid of stale gas, for example, then one way is to keep your traction battery fairly low, and use CHARGE mode to drive that first 5 miles at 20mph. This will replenish the battery while the gas engine runs to provide you the heat. The engine works harder than just front defrost only, making more heat and you will end up with more SoC in your battery. One caution is that CHG mode only worked to charge the traction battery up to 80% on the dash display, So if you already have more than 80% charge then you can't use CHG mode. But IMHO, firing gas engine when not necessary, either by pushing front defroster or using CHG mode are waste of gas and produce more pollution, so they should be avoided as much as possible.

 

So, you're saying HV mode will not automatically start the gas motor in your situation? Then how about CHARGE Mode, won't that force the gas motor to start?

 

In HV mode the car decides for itself whether it wants to run electric or gas. Charge mode won't work if the battery is above 80%.

 

So drive in EV until battery low, then Charge Mode to run the engine.

 

When I know my trip will be beyond EV range I toggle HV mode and then back to EV mode shortly after starting the trip. This warms up the engine before switching it off. I think this makes sense in the cold.