(1.School of Mechanical Engineering,North China University of Water Resources and Power，Zhengzhou 450045,China;2.School of Mechanical and Vehicle,Beijing Institute of Technology,Beijing 100081,China.)
The CFD simulation model of a hydrogen-fueled internal combustion engine (HICE) including the simplified chemical reaction mechanism was established based on Converge software and the in-cylinder combustion progress and NO generation characteristics of HICE were studied. The simulation results show that the in-cylinder combustion progress is composed of ellipsoid flame stable propagation and rapid turbulent combustion in turn. Due to the very rapid combustion of hydrogen, the OH concentration decreases rapidly at the end of turbulent combustion and the temperature and NO mass reach the peak, then the incylinder temperature and NO mass decrease gradually. The final emission depends on the peak temperature and NO decomposition time in the hightemperature area. The peak of NO mass increases with the increase of peak temperature and the NO decomposes less due to faster temperature decrease. The maximum in-cylinder temperature becomes lower by using exhaust gas recirculation（EGR） and NO decomposes completely at low speed, which leads to lower NO emissions.
