I recognize that glazed eye look Tom.
I hope to add Adiabatic and Isothermal curves and calcs to the software this week. What does that do? It will help users "see" how much heat is being absorbed by the chamber walls, head, and piston.
What the heck are these things? The Adiabatic curve represents the pressure if the compressed gas does not loose heat to the engine. Isothermal is if the charge is the same temp regardless of the compression.
With these guides, the user should be able to see the progression of the fuel burn. That is, when is the fuel actually burning. It is one of the pieces needed to predict what changes in timing would do to the pressure curve.