The automotive industry is undergoing a substantial transformation driven by increasingly stringent regulations aimed at reducing greenhouse gas emissions to achieve sustainable mobility. In this context, Stellantis is continuously committed to reduce the environmental impact of its vehicles, in line with the newly updated legislation, by focusing on the development of highly efficient engines suitable for hybrid integration. The aim of this project is to study and analyze the combustion for an already existing Spark Ignition (SI) engine, developing a version optimized for hybrid powertrain, named Dedicated Hybrid Engine (DHE). The project follows, after a detailed analysis of all possible solutions, a well-defined path which enables significant results in terms of efficiency improvements through the adoption of mature existing technologies.