skiingman: I know the engine I proposed is not an example of a realistic engine. I am trying to keep things simple so you can understand.
It is simply not true that an engine of this type would not run under its own power. It would run in a most ineficient mode, but it would run.
At the end of the induction stroke there is one cylinder's worth of mixed gases in the engine. At the end of the power stroke on the example engine there is one cylinder's worth of other mixed gases in the engine. They may be hotter, and the pressure may be high, but the volume is still one cylinder's worth. At the end of the exhaust stroke this has been ejected. What happens next outside the engine has no bearing on this example.
As this carefully simplified example shows, your analysis of what would happen at various load conditions is wrong.
Anyway, I have had some useful input from the usual suspects, whose views I respect, so no more posts on this thread from me. Hasta la vista, baby.
Dick