COMBUSTION PROCESS IN SPARK IGNITION AND COMPRESSION IGNITION ENGINES

Abstract

The process of normal and abnormal combustion in SI and CI engines has been explained in the present paper. In case of SI engine, the air-fuel mixture is prepared in the intake system and then the mixture is inducted into the cylinder through the intake valve and the compression takes place. Then, the flame is generated in a turbulent manner. The high speed motion of flame development has been illustrated. The travelling of Flame has been explained and the engine flame-trace has been shown. The detonation and pre-ignition in spark-ignition engine have also been described. In case of CI engine, high-pressure fuel is injected at the end of the compression stroke into the cylinder. The injected fuel first evaporates and then mixed with the compressed hot air and then finally the ignition takes place. The combustion process in diesel engine has been illustrated. The detonation in compressed-ignition engine has also been given. The comparison between detonation in spark-ignition and compression-ignition engines has been done. Finally, the paper gives the clear view of the combustion process in SI and CI engines.