I live in Montreal where winter mornings can be quite cold. If the outside temperature is not lower than 14 °F, my Prius Prime will allow me to drive on battery. Sometimes, the battery runs out while I am driving at high speed on the highway and... the cold ICE kicks in, at high RPM. I don't dare imagining what this does to the pistons. To avoid this, I switch to ICE before reaching the highway, while waiting at a streetlight or if am stuck in traffic. But once the ICE starts, I cannot switch back to EV for another 10 min. The idea of idling for this time seems counterintuitive to an EV driver. I also find the car embarassingly slow when going uphill or when trying to pass another vehicle while being tailed by an impatient driver. In these situations, I wish I had the option to switch to EV, which is not possible during the warm up cycle. Is it worthwhile to "suffer" these inconvenients to safeguard the engine? Or does the Prius Prime have some technology that minimizes the negative effects of the cold on a running engine? Thanks
The engine is spun before being put under a load and the traction battery is offloading a good portion of the load from ICE during the warmup. Bottom line is it sounds a lot worse than it actually is.
The car won't spin the engine at high rpm until it warms up (Unless you really demand power.). It's loafing with lots of help from the battery till it reaches a temperature where it can run more cleanly. Don't forget, this car's primary objective is reduced emissions. To see it at work, watch your instantaneous mpg indicator when the ICE starts. You'll see it staying really high for a while as the engine warms. Then it'll drop once the engine is warm enough to take over. Then it'll drop some more as it pays back what it borrowed from the battery during warmup. You can also see this as the remaining EV miles go down during warmup and the come back up after warmup.
During winter, if I know the distance I am going to drive is longer than EV range, I starts my car in HV mode. Once the engine finishes the warm-up cycle, I then use EV mode intermittently but keeping the engine not get too cold so that it doesn't have to go thorough the warm-up cycle again and again. For an added benefit, I get much better heating off from the engine than heat pump.
Note that on the Prius, the engine is spun to about 1,000rpm before the engine is fired up (vs 100-200rpm with a starter motor on a regular car) so the camshaft is already rotating near idle when you hear the engine fire up. When the engine is cold, the car primarily relies on the electric motors (so engine and battery feed the motor to power the wheels, to keep engine rpm low). Only if you're in EV mode and decide to climb a hill or a mountain, will I worry about the sudden "shock" on a cold engine.
I wish there was a way to somehow greet visitors here who are all worried about their Primes that this car is not fine china (well, except for that brittle acrylic grill. LOL!). It's made to be driven and to be extremely care free.
Yeah, my understanding (with regular 3rd gen) is that the engine is just running at an elevated idle speed, and all propulsion is electric, for the first few minutes. I can see this if I take the "scenic" route out of our neighborhood: I need to coast to a few corners, then accelerate beyond them. An RPM indicator would help (thanks Toyota...) but judging just by ear, the engine RPM does not change during the this drive.
I'm loath to hook up my scangauge, it was causing problems. Just trust me, the idle speed I hear is steady Eddie.
The system will "borrow" energy from the traction battery to move the car, temporarily reducing the state of charge below the usual minimum, until the temperature reaches some threshold. The "debt" is then paid back.
The car doesn't (and can't) always warm up the engine gently. If the battery is cold (around or below freezing, which usually only happens if you haven't charged in a while), sometimes it's not able to supply enough power to meet the acceleration demand. In that case the engine starts and starts driving the wheels immediately. I've caught this with Hybrid Assistant a couple times. For example here are some screenshots. The negative engine power is the engine being spun up. Then it quickly ramps up to a fairly high output. The engine goes to 26 kW and over 2000 RPM in a few seconds. This happened pulling out of my neighborhood onto s 30mph road, not driving up a mountain or anything. I was surprised when the engine started. I think the reason is, I forgot to plug in my charger the night before, so the charge was "stale" which causes the Discharge Current Limit (DCL) to be low, a little over 30kW.
2,000 RPM, while being higher than regular cruising speed, isn't terribly fast, especially with 0-W20 oil and achieving oil pressure before loading the bearings with combustion forces. If it was running straight 30 or 40 weight oil, then I think I'd be concerned.
I agree it's not terrible, and the engine started out at only 32 degrees F (not really that cold). That's just the best example I've recorded so far of the car bypassing the warm-up cycle. It would be a lot worse if it happened while merging onto the highway, or while going up a big hill. I'm not going to go out of my way to intentionally trigger it in one of those places, because it can't be great for the engine.
I agree. I wouldn't do it just to try to be abusive, but then again, I wouldn't be afraid to do it if it's what I needed to do.
You're fine. This is where the miracle of synthetic oil is keeping you safe. This is why you bought the good stuff and checked the dipstick a few times in between oil changes.
