Optimally Timing ICE Activation

My commute is about 22 miles (each way) and I always fully charge my PiP at home and at work before I leave. I have no choice but to always activate the ICE (switch from EV mode to HV mode) and burn some gas when driving in each direction.

I do drive at slower city speeds at both ends of my journey (2 miles at each end) so there is more than enough EV reaiming such that I must use a lot of my EV when driving at 55 MPH.

My question is: For what driving condition/circumstance would it be optimal to initiate my ICE's warm-up cycle (that, once started, can not be stopped until the warm-up period is complete)?

1) Should it be right before going up a hill or would that not be optimal?
2) How about turning it on (switching to HV mode) at one of the many stop lights on my journey (to me that would seem to waste the ICE power generated during the warm-up cycle)?

Certainly there isn't too much to gain here... but I am always interested in finding ways to maximize my fuel efficiency.

 

I thought that blending only took place above 62MPH. That would mean very poor gas mileage (driving at 65 MPh, for example). I am sticking to 55 MPH in EV mode. I want to know when to turn on the ICE. Early doesn't make sense to me because the engine could get cold enough to turn on near the end of my trip when I want it to be in HV mode yet still only using the small bit of EV that is left.

 

I turn on the ICE by switching from EV to HV mode. I have not had any trouble (so far) in unintentionally activating the ICE. Since I have more EV than is needed at speeds around 20-30 mph, I choose to drive on EV (55 mph) on the rest of my route. In my normal day to day driving, I do not ever blend (except when my car automatically does it when I choose to be in HV mode).

Certainly winter will change things but right now it is unusually warm in Minnesota. I will need heat and the EV system may also require heat to function.

 

Thank you so much for your post. You pretty much answered my question. It sounds like the best time for me to switch over from EV to HV mode (initiating the ICE warm up) is when I won't be demanding a lot of power from the engine. Maybe when I'm driving a constant speed and not expecting any stop lights. I will admit this is sort of counter intuitive (to me, at least) because I know the engine generally is more efficient when you demand a miserate amount of power from it. I guess that warm-up is different.

One thing I've noticed when switching to HV mode for the first time is that the EV miles drops about 0.4 mile initially (ICE warning up). I think the car realizes that EV power is more efficient than ICE power during warm up. The car does seem to know that the EV miles it 'bowwors' must be returned (and they are eventually, sometimes with interest).

I like turning on the ICE close to the time when I have 'just enoigh' EV power saved for the final slow section of my journey. This is sometimes not so easy to do! This has the advantage that my ICE will still be warm from the warmup and not turn on immediately when the EV miles hit '0' (I am free to drive slowly for a little bit longer on the full HV battery, as long as I don't accelerate very strongly, I can get an extra mile).

If you run out of EV miles and the ICE has never been warmed up, your ICE will turn on immediately when EV distance = 0 (a source of anxiety if you hope to have a pure EV drive). With the ICE already warm, you can get just a bit more EV driving for free when EV miles = 0 (and I now exploit this extra battery power, further improving my gas mileage).