Quote:
Originally Posted by Isaac Zachary
Technically Toyota hybrids don't have an actual neutral. The engine is always geared to the wheels through the transmission. It's how much torque the second motor/generator creates that determines the torque on the wheels and at the engine.
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If you squint really hard you could say the car is electrically disconnected from the wheels, though that's just being pedantic at that point (considering neutral also stops the engine from being able to charge the traction battery).
Quote:
Originally Posted by redpoint5
The Prius doesn't DFCO when it starts up do to long periods of regen. It high idles the engine until coolant reaches 130 degrees. It is never running the engine AND engine braking unless you shift to L.
I know all this because I watched coolant temperature, MG1 and MG2 power, closed loop, fuel consumption, among dozes of other things. Plus, you can simply hear the engine high idling and contributing no power to the car or deceleration.
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My assumption here is that if your car's battery is full, then it cannot keep using regen braking alone to slow down anymore, and using the mechanical brakes for long periods of time isn't an option either.
You say your car isn't using engine braking, but the car has to be throwing away battery energy somewhere in order to keep regen braking working. The engine doesn't need to do anything to the wheels as long the energy input to spin it up is more than the energy output from the idle fuel rate, thus discharging the battery for more regen braking.
Outside opening all the windows for drag, the only ways i know a hybrid car can slow down are mechanical, regen, and engine braking. It can't be none of them.
I am curious whether a conventional car would disable DFCO if one was to engine brake down a mountain for so long that the engine internals have cooled to ambient.