This spreadsheet provides a template for analysis of the Otto (spark-ignition, internal combustion) Cycle. The user fills in the data in the top grid (from other software or table lookup). From that data, the cells in the second grid are updated, and Pressure-volume (P-v) and Temperature-entropy (T-s) diagrams are generated. If you use the thermal properties Excel add-in from CoolProp, then you can have the whole spreadsheet update whenever any input parameter is changed. This updated spreadsheet includes the capability of doing a sensitivity analysis. Turn up your volume before opening!