Environmentally friendly mobility is a primary strategic goal of the EU that could become more easily achievable through innovative technologies, electrified solutions and use of alternative fuels. The EU-funded PHOENICE project will develop a C-class SUV plug-in hybrid vehicle demonstrator whose fuel consumption and pollutant emissions will be minimized under real-world driving conditions. In this work, a GT-Power 1D engine model will be initially calibrated to the available experimental data to provide the plant model for the HiL bench setup on which the PHOENICE engine control unit will be developed. Subsequently, the model will be updated with the expected new features of the PHOENICE engine and an initial optimization will be performed to estimate the theoretical gain in fuel consumption and hence CO2 emissions..