23' Prime - Gas engine starting in EV mode

I believe it’s more about the battery not being able to handle much regen when it has lots of charge and particularly when it is cold. The car can’t switch to mechanical brakes so it starts the engine and the engine then needs to run long enough to warm up.

Try coasting down the hill in neutral and the engine will not start.

Also pre-warming the car for 20 minutes, using the app, helps prevent the engine from starting.

 

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I don't think that is right. I will pay more attention to the contributions of both battery power, battery pack remaining charge and engine power next time I take that route. If I remember correctly even when the engine cycles on it is still not making a significant contribution to driving the car down the road. I am driving in EV mode and using Predictive Efficient Drive when I have made these observations. Unfortunately there isn't a PID I have found in OBD Fusion for battery temperature.

Do you have a reference for your theory regarding battery not being able to handle regeneration current from MG2? The gauges I have in OBD Fusion are capable of showing regenerative power and I have never seen any indication in regards to the hybrid system not being able to handle regenerative power when going down hill.

Here is an excerpt from ChatGPT regarding what Toyota has referred to as "Engine Exercise."



I believe the algorithms on the hybrid control ECU are trade secrets. That partially explains why it is hard to find information in regards to what is going on with these short run engine cycles.