I know that rev hangs are intentionally introduced to modern vehicles that operate on electronic throttle bodies, by programming the ecu to close the throttle valve slowly (in gasoline engines) even when you let go off the accelerator pedal quickly ,so that you can reduce emissions.
I have read that when you close the throttle valve quickly it takes some time for the fuel injectors to cut off the fuel supply making the air-fuel mixture available in the engine to be richer thus causing higher hydrocarbon emissions. So my question is "Will letting go off accelerator at high engine load conditions (say you are flooring it and letting it go completely) will increase the duration of rev hang?".
My logic behind this is that fuel injector will be supplying more fuel at higher loads and hence letting go accelerator at higher load will result in more amount of fuel injected before it responds and cuts off fuel. To burn of this extra fuel completely then you would require more air and hence increased duration over which the throttle valve has to be kept open by the ecu (i.e rev hang). Also in port fuel injected vehicles there will be some fuel that wets a portion of intake runner and this fuel that wets the runners cause more rev-hang in port fuel injected vehicle.
Here is the video explaining rev hang: https://www.youtube.com/watch?v=mm6SSeLivqE
Also a counter argument to this could be that the throttle valve will be opened more at higher loads so the ecu doesn't need to maintain/keep the throttle valve open for an even larger duration to burn the excess fuel injected.
Here is video that seems to show that you have more rev hang at higher load: https://www.youtube.com/watch?v=INtfe3xJXF8
Also what are all the factors that can affect rev hang?
