Hydrogen presents a promising alternative in the realm of large-scale thermal power generation, particularly when integrated into internal combustion engines (ICEs). This research looks into whether it is possible and helpful to use a diesel-hydrogen dual-fuel engine that works with a new constant volume combustion phase (CVCP) strategy and is simulated using OpenModelica. The combustion model incorporates a double Wiebe function to characterize the combustion process comprehensively. Results indicate significant improvements in peak pressures and temperatures, alongside emission reductions, particularly NOx, with increasing CVCP duration. The study sheds light on the potential of hydrogen integration in ICEs for enhanced efficiency and reduced environmental impact.