Abstract: Homogeneous Charge Compression Ignition (HCCI) engines have become potential power units to satisfy the stricter emission regulations and obtain higher thermal efficiency values. The HCCI operating principle has been widely investigated in order to improve the ability to control the HCCI combustion phasing. The zero dimensional model, Wiebe function, is known to be able to simulate the general behavior of engine combustion. However, the standard Wiebe cannot represent dual fuel HCCI combustion and a two-stage Wiebe is suggest here as a solution for this problem. This study describes this work and concludes that a double-stage Wiebe is viable of predicting the dual fuel HCCI combustion more accurately than the standard Wiebe. The work also showed that, in the dual fuel environment, each fuel acted as a single fuel according to its own properties especially if the gaps between the injections of the two fuels are wide.