Percentage of odometer reading that ICE was actually running?

Even if it was, and based conditionally on jacek's comment about potential engine longevity problems, why is it so important to you? And doesn't it stand to reason that the only reason Toyota would specify synthetic oil, is to prolong engine life? My dealer included "free oil changes for life" with my car, and given the higher cost of synthetic oil, don't you think it was in their best interest to do so?

 

It's not that important to me. I'm here to learn, and part of that involves asking when something doesn't make sense to me. In fact your and Jacek's conversation prompted me to do some searching around for Prius engine failures. I couldn't find any. I'm sure they exist, but I can't see anything about this being a common problem. Id be interested to see any data that indicates otherwise.

 

As jacek says, if you poke around the gen II forums long enough, you may find it.

 

Since no one tried to give an estimate yet, I will. I would say that the ICE runs 60-90% of the time. I would say it is more like 70%-85% for most drivers with "normal" driving requirements. There will be those that fall outside of those numbers but, they will be the exceptions.

 

I don't consider my Prius Plug-in primarily as an electric vehicle. If I were using it on EV power most of the time, I'd have been well-advised to buy a Leaf or a Volt. Most of my mileage comes as a result of burning gasoline, as with a regular Prius. When it's convenient, I plug it in, but I generally don't go far out of my way to find plug-in power.