Combustion modeling plays an important role in an internal combustion engine (IC) simulation to predict in-cylinder flow behavior development.Therefore, this work presents a predictive thermodn. model of an IC engine fueled with gasoline, LPG, and LPG-hydrogen blend, using zero-dimensional modeling.The effects of the compression ratio combining hydrogen enrichment on thermodn. process are numerically evaluated on gasoline engine fueled alternative hydrogen-LPG fuel.Moreover, hydrogen volumetric fractions of 0%, 5%, 10%, 15%, and 20% were used in the simulation prediction.The main finding in this study was that the compression end temperature in-cylinder pressure, the thermal efficiency, and the supplied power prove that a compression ratio between 9 and 10 is the most reliable.Hence, comparisons with exptl. results justify the choice of the compression ratio.