I'm curious if the stop and start of the ICE by the Pri causes additional wear and tear as compared to just having the ICE on all the time.
The other linked thread is pretty much the answer. To amplify, MG1 (the smaller of the two MGs) is the "starter" for your ICE. In effect, it acts like a "pre-oiler" for other cars. You can install a pre-oiler on any piston engine car, but that can be messy, and the more external oil plumbing you add, the greater the risk of inconvenient, or even fatal, oil system leaks. In the Prius, on command from the ECU, the HSD runs the ICE up to about 1k rpm, "no load," before it adds fuel and spark. This allows the car to build critical oil pressure before the stress of the actual start occurs. In a normal gas engine, the bearings, rings, valve train, etc are all working hard for a few moments before the full supply of oil arrives. Not a factor in a Prius, even on the first start of the day (though first starts of course involve cold oil, not good, but nothing like a cold, dry start in a regular car).
