BIGABQ

OK I'm getting older and some things are bye me but! Morning are getting colder engine runs at 1100 to warm up OK I understand that. But after running around town and engine is warm, I checked again, still at 1100 RPM. Shouldn't it be lower or is that what the batteries need?

SLH

Toyota has used essentially the same scheme in several generations of hybrid systems. Like the previous hybrid models, the 300h never actually idles.

The computer decides when it needs the engine to run, and turns the engine on & off as needed. When the computer runs the engine, it runs it an an efficient speed for the work that needs to be done. That work includes moving the vehicle, recharging the battery, and keeping the catalytic converter warm. In cold weather, the catalytic converter needs more warming than in summer.

I have long since given up second-guessing the engineers who programmed that computer. They put hundreds of thousands of hours into the project of optimizing the trade-offs.