Hydrogen is expected to play a significant role in mobility and transportation as a form of energy source. To assess the effects of hydrogen as a gradual replacement fuel for internal combustion engines, a preliminary 1D thermodynamic simulation was carried out using AVL Boost for 0 vol%, 4 vol% and 8 vol% hydrogen content. Calculations were based on independently published research results, and focused on peak firing temperature (PFT), brake specific fuel consumption (BSFC), nitrous oxide emission (NOx), and carbon monoxide (CO) emission values. Results showed a decrease in BSFC of up to 3 g/kWh and ca. 5 mg/kWh decrease in CO emission with 8 vol% hydrogen, but also highlight an increase of PFT by 14 K, and ca. 0.5 g/kWh additional NOx production at high loads.