The Isolated Combustion and Diluted Expansion (ICADE) internal combustion engine cycle combines the advantages of constant volume combustion of the Otto cycle with the high compression ratio of the Diesel cycle. In this work we studies the effect of Isolated air mass on the efficiency of the cycle, the analysis shown that the decrease of Isolated air mass will increase the efficiency of the cycle, the large dilution air mass will quenches all NOx forming reactions and reduce unburned hydrocarbons. Furthermore, the effect of Fuel / Air ratio on the efficiency studies the analysis shown that the increase of Fuel / Air ratio will increase efficiency of the cycle.