CO2 emissions from a spark ignition engine operating on natural gas-hydrogen blends (HCNG)

► An indicated cycle simulation for spark ignition engines is developed. ► The fuel consists of natural gas and hydrogen blends (HCNG). ► Maxima cycle pressure increase with increasing hydrogen content. ► CO2 emissions decrease as hydrogen content increases. ► CO2 decrease and power increase show a nonlinear variation with increasing hydrogen.