Energy Flow - Orange Engine

Hi,
I received my 2018 PHEV yesterday and today whilst going up a hill the engine seemed to be revving a little excessively (battery was pretty much empty). I noticed on the Energy flow display that for a split second the image of the engine changed from blue to orange. Whilst going down the hill the engine was not over revving but the engine image turned orange again.
I’ve tried searching but cannot find anything on the net or the user manuals.
Anyone idea what it means please?
Thanks

The Orange arrow means the engine is driving the wheels directly, it will point from the engine down to the wheels. When you see the blur arrows via the battery, the engine is generating charge that is feeding the battery and electric motors.

Steve

1) Orange means engine is driving front wheels directly via fixed gear
2) Blue means engine is generating electricity via the generator.

1) Means fixed RPM (related to speed) and thus limited output from the ICE.
2) Can mean:
2a) generated electricity is used to drive the E-motors
2b) generated electricity is used to charge the battery or

1 and 2a can happen at the same time, when you select 4WD mode (must be driving faster than 40 MPH)
1 and 2b can happen at the same time (must be driving faster than 40 MPH)
2a and 2b can happen at the same time (although without additional tools, such as PHEVWatchDog or EvBatMon, you will not be able to tell when it does, due to ill designed graphics)

When driving up hill, either your speed went below 40 MPH, which caused 2b (and perhaps 2a) to occur OR power demand was such that available power in mode 1) was not enough (due to limited RPM and empty battery) and the car had to fall back to 2b (and perhaps 2a) to allow for more RPM (and perhaps recharge the battery a bit).

Steve / Anko,
Thank you for the prompt and detailed reply.
BR
Ben