Controlling the Power Output and Combustion Phasing in an Homogeneous ChargeCompression Ignition Engine

In the development of Homogeneous Charge Compression Ignition (HCCI) engines, simultaneouscontrol of combustion phasing and power output has been a major challenge. In this study, a newstrategy is developed to control the engine power output and combustion phasing at any desiredoperating condition. A single zone thermodynamic model coupled to a full kinetic mechanism ofPrimary Reference Fuels (PRFs) is developed to predict characteristic parameters such as; Start ofCombustion (SOC) and Indicated Mean Effective Pressure (IMEP) and also thermodynamic constantparameters for processes through an HCCI engine cycle. A dynamic interactive control model has beendeveloped for the entire cycle of a HCCI engine to predict combustion phasing and IMEP.The resultsderived from the developed model are validated against experimental data for a single cylinder Ricardoengine. A two input - two output controller is then designed to track crank angle at which 50% of incylinder fuel mass is burned (CA50) and IMEP by adjusting the input data. In this study two controlmodels are presented; open loop and closed loop. Performance of the controller is tested on a physicalHCCI engine model to evaluate the tracking performance and disturbance rejection properties. Resultsindicate that the designed controller is capable to accurately tracking both CA50 and IMEP whilerejecting the disturbances from variations in the engine speed and the intake manifold temperature