Control Oriented Modeling of Combustion Phasing for an HCCI Engine

A promising method for reducing emissions and fuel consumption of internal combustion engines is the Homogeneous charge compression ignition (HCCI) engine. Control of ignition timing must be realized before the potential benefits of HCCI combustion can be implemented in production engines. A model suitable for real time implementation is developed and this model is able to predict ignition timing with an average error of less than 2 crank angle degrees. A modified knock- integral model (MKIM), with correlations for gas exchange process and fuel heat release, is used to predict HCCI combustion timing (CA50, crank angle where 50% of the fuel mass is burnt). The MKIM model is parameterized using a thermokinetic simulation model. Experimental data from a single cylinder engine at several HCCI operation conditions and three fuel blends is used to validate the model.