Combustion Simulation of Natural Gas in Homogeneous Charge Compression Ignition (HCCI) Engines and Analysis of Effect of Engine Operating Conditions on Combustion Initiation

Homogeneous Charge Compression Ignition (HCCI) engine is considered as a new combustion technology based on auto-ignition with higher thermal efficiency and lower emissions compared with the classic engines. In the present research, a theoretical model is provided to study the combustion regimes of HCCI engines fueled with natural gas using detailed chemical kinetics. Simulation results show that the auto-ignition processcan be described using specific definitions of HCCI engines. Also the effects of combustion control parameters on the combustion initiation and in-cylinder pressure have been studied. The model is able to predict conditions for a stable controlled combustion applicable for a wide range of operating conditions. The P-θ curves obtained from the model is compared with the data published in the literature and the comparisonshowed a reasonable compatibility in prediction of combustion initiation