Quote:
Originally Posted by NeilBlanchard
Having better coasting with no idling is more important to high efficiency. If you accelerate less, and then coast, and only use regen to slow down, then that is better overall.
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The only caveat I would add.
It is important to remember the source of the vehicles applied energy.
Coasting is not a source of energy ... it is consuming the kinetic energy that the engine / motor ... already applied to the vehicle to get it to any given speed / position.
The energy that the engine / motor applied to the vehicle to invest in that amount of kinetic energy / location ... that was done at some ___% efficiency of that motor / engine.
That initial __% of the motor/engine ... that applied the fuel energy to the vehicle ... is the max efficiency % ... all other down stream effects only reduce the final net vehicle __% ... to some value bellow that initial __% Motor/Engine conversion efficiency.
Coasting is useful ... As a Engine/Motor control strategy to avoid the low efficiency operating situations of that engine/motor.
But like everything else ... there are pros and cons.
Using coasting as a motor/engine efficiency optimization strategy means one is introducing variable vehicle speed into the equation ... and variable vehicle speed is a aerodynamic penalty... meaning it causes the vehicle to need more joules of energy ... to travel the same distance in otherwise the same conditions , average speed , weather , etc.
Thankfully ... at least for most ICE based designs ... there is a significant gap in the magnitude between ICE efficiency variation and the imposed aerodynamic penalty.
But ... you don't get something for nothing , with coasting ... so keeping in mind the pros and cons ... can be useful.