Mechanistic Modelling Approach to HCCI Combustion

Homogeneous Charge Compression Ignition (HCCI) has become a promising alternative combustion method over conventional methods of Spark ignition (SI) or Compression Ignition (CI). HCCI combines the advantages of SI method (homogeneous charge) and CI method (compression ignition). It has also been proven by every researcher that there is almost 95 per cent reduction in NOx emissions with HCCI combustion, and other emissions such as CO2 and HC are comparable to SI engine, which can be reduced using after treatment systems. However, it presents a challenge with respect to controlling sensitive parameters that have profound effect on the outcome. As with SI and CI engine, there is no definitive start of combustion event, which can be controlled independently. In HCCI combustion, air fuel mixture is ignited spontaneously throughout the cylinder and this event is governed by chemical kinematics. Therefore, it is important to understand the inherent chemical reaction process and its effect on pressure and temperature within the cylinder. Through mechanistic modelling, the combustion process can be simulated and the relationships between input and output quantities can be examined. For this research paper, a zero dimensional single zone model has been created to model the effects of EGR % on Heat Release Rate (HRR).