Numerical study on effects of EGR on combustion and NOx emissions of gasoline blended dissociated methanol gas engine

Exhaust gas recirculation (EGR), which can reduce NOx emissions effectively, has been widely studied in engines, but there are few studies using EGR on gasoline blended dissociated methanol gas (GDM) engines. To reduce the NOx emissions of GDM engines, investigation is conducted based on numerical simulation in this study. The accuracy of the engine numerical model is first validated through experimental data, and then the effects of EGR on GDM engine performance are studied, including combustion characteristics and NOx emissions. Numerical simulation results show that the application of EGR reduces the cylinder pressure and the heat release rate of GDM engine, and delays the corresponding crank angle of their peak value respectively. The application of EGR also delays the combustion center, and extends the ignition delay and combustion duration. As EGR rate increases, the NOx emissions decrease significantly. This study offers valuable insights into the potential application of EGR technology in GDM engines.