Sensitivity Analysis of Auto-ignited Combustion in HCCI Engines

Auto-ignited combustion in HCCI (Homogeneous Charge Compression Ignition) engines highly depends on temperature and composition of the cylinder charge. In this paper, characteristics of such combustion are investigated using a control-oriented HCCI engine model. First, thermal equilibrium points are obtained from the model and the sensitivity of combustion phasing around those equilibrium points are examined to understand characteristics of auto-ignited combustion. Finally, a method to effectively visualize the sensitivity of auto-ignited combustion is presented to explain how combustion characteristics change as engine operating condition changes.