FastMover — Just a quick post here. Toyota's "Master" US patent #6 131 680 on their hybrid system (attached) has quite a lot to say about their ICE and MG/battery management and control strategies.

Stan

 

Being a newbie, and not that technically inclined, I have an observation/question for you to ponder. I have read this entire thread, albeit with some confusion, and have noticed something that is neither 'heretical mode' nor 'fuel cut' (nor does it add to this discussion, particularly).

On a slight downward incline I have accelerated above 80km/hr (as the speed limit permits) and then let off the gas, and then ever-so slightly pressed on the gas to maintain the flow of traffic - at first the display (between the steering wheel - I do not have Nav, nor SG or II), reads recharge, then as I continued to depress/feather the gas, ever so slightly, the arrow changes from battery to wheels and the consumption meter reads 0L/100km - I can maintain this state for a long period, so long as the grade is slightly downhill (when things level out the ICE usually kicks in).

Though I appreciate that this is not heretical mode, nor a coasting/above 65km 'fuel cut' mode, I have been pleased with the savings, and wonder what is going on (0L/100km while the display reads battery supplying power to the vehicle/ MG1 running the show)? As a newbie, I suppose I need some direction to other threads that highlight this phenomenon...

Thanks from a fellow Canadian!

 

Forest — Coasting at 80 km/h you are indeed in fuel-cut mode if the FC gauge reads precisely 0 L/100 km. The ICE is being spun by MG1 (powered by MG2) to prevent it from over-revving, but no fuel is being used. This requires work to be done on the ICE, and so causes a mild engine braking (deceleration) to be felt on the wheels, and on the MFD an arrow goes from the wheels to the battery indicating that battery charging is taking place as well (as long as the battery isn't "full"). If you feather the accelerator just the right amount to get rid of all arrows on the MFD, the car is now gliding freely without additional battery charging, but work is still being done to spin the ICE, and this has to come from somewhere, presumably the battery. So, you're running the battery down (slowly) when you do this. If you press slightly more on the accelerator, and the car determines that the additional power that you're requesting can be best supplied by the battery on its own, an arrow now appears on the MFD from the battery to the wheels, and the battery is now not just spinning the ICE but also powering the wheels. You're now drawing even more power from the battery, but if you're gentle in your request, the FC will continue to read 0 L/100 km and no fuel will be used. It's still fuel-cut. The discharge rate of the battery will be correspondingly greater, though. Don't forget that the battery will need to be subsequently recharged, so this energy will eventually be made up by burning fuel — there's no free lunch!

Stan