Abstract: By the computational fluid dynamics, computational heat transfer and chemical kinetics, a model for pulverization and mass transfer of diesel fuel in FCD-II cetane number machine was established to simulate the changes of combustion parameters of temperature, pressure and speed of airflow in the engine. The results indicate that the temperature and pressure of air due to being compressed is high enough to ignite the fuel at the top dead center (360o angle position) in the case of invariable air volume. When the reading value of the air flow meter is increased from 200 to 800, the compression terminal temperature rises from 426 ℃ to 503 ℃, high enough to ignite the fuel. During fuel combustion, the parameters are increased sharply by rapid combustion in local region in the cylinder and transferred to other regions, resulting in instantaneous variations of temperature, pressure and air speed in cylinder.

Key words: airflow control, cetane number, diesel, combustion