Quote:
Originally Posted by Mr Twisty
Heat lost is unused potential energy but it seems it would only be efficient if there was a large temp difference between the cylinder and the exhaust gasses.
Once the cylinder is heat soaked would efficiency drop to near nothing?
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I'm in slightly over my head here (its been quite a while since Thermo & Heat), but I'll give it a whirl ...
an engine works because hot gasses push against a piston. In doing so, they expand. As they expand, they cool.
It would seem to me that a cold cylinder would rob heat from the expanding gas -causing it to lose pressure faster, therefore producing less force against the piston (causing less torque, and by extension less power). Conversely, a hot cylinder would allow for more heat to be used to push the piston.
Now, as for the 5 stroke ... its interesting, but an alternate solution exists: leave the intake valve open for a bit on the compression stroke. The net result is more or less the same, but it requires essentially 0 extra parts.