Determining combustion burn time...

This is a pretty cool site... I decided to register and ask my very first question....

I am developing an Excel Spreadsheet tool for learning purposes which demonstrates effects on power generation of automobile engines by changing various specifications like charge temperature, rpm, bore, stroke, displacement, manifold pressure, volumetric efficency, etc.

The part that I don't have figured out is the part I am least familiar with... combustion characteristics and burn time. I know that rate of change effects, mixture, temperature, pressure, etc effects burn time... but how. I would like to have a magical equation that takes in account mixtures (of Air, N2O, Methanol, Ethanol, & Propane), my changing volume over time (and rate, of course temp and compression pressure, etc.

This is purely a free learning tool and will never be used for money.... hopefully that helps someone promote some work for me. I appreciate any and all help. I actually own a perfect book for this, however it is at my friends house some 8hrs away - "Internal Combustion Engines Fundamentals" by John B. Heywood. Thanks!

Frank Katzenberger