i think it is because at a certain speed and above, it would cause tranny damage if the engine fired from stationary. and yes, i think you lose ev efficiency between the speed the engine starts rotating to the speed it fires. iirc, you can see this with a proper gauge. scangauge?
mmm How wuld it do that? On mine, if I'm going 65mph, and slow down, the engine cuts off. I honestly do not know if it is actualy turning, though if I put it in "B", I can tell. Then when I speed up, the engine kicks in. The transmission, or certain people, whatever you want to call it, is already driving the car. There is a clutch, so it possibly slips some before completely engaging and turning the engine. At least to me, that seems to be the best way to do it.
i'm not sure there is a clutch that can actually slip. i think they might have added one on prime. idk, i have never done it. you might try watching john kelly's youtube explanations. he might have it, or at least on the gen 2. and some recommend 'new car features' to find these details. not sure if that is with tech info or elsewhere. i just remeber reading about the limitations over the years, gen 3 improvement and pip improvement.
I know it's not a direct contact. That wouldn't last long. A clutch does slip, or there would be a hard BAM when engaged.
I was just curious. I only semi read about the Prius Prime. And from what I understood, you can run off the battery for about 40 miles(?) Then the engine kicked in to charge the battery if you didn't stop and plug it in to charge. How it goes about doing all that I never went far enough to know.
the engine kicks in to make it a regular hybrid, just like yours. there is also 'charge mode', where the engine will charge the battery back up to 80% while you're driving, but at some cost for extra fuel burned.
In a regular (non-plug-in) 3rd generation, when you're coasting above about 45 mph, the wheels "spin the engine without gas" at about 992 RPM in order to avoid overreving MG1. There is no clutch or brake in the transmission.
The clutch, is where a standard clutch, or torque converter would be. That's how the engine is started.