Model-Based Diesel HCCI Combustion Phasing Controller in Integrated System Level Modeling

This work integrated a CA10 (crank angle at 10% heat release) controller into an integrated engine, emissions and aftertreatment model platform. Two CA10 phasing targets were chosen to analyze how advancing (or retarding) the target combustion phasing (CA10) affect the formation of NO

and CO. The effect of intake valve closure (IVC) timing, which is the control mechanism for maintaining the target combustion phasing, on the cylinder trapped mass, and hence the charge temperature after compression is detailed. Finally, the relation between combustion phasing and the blow-down process leading to the exhaust process is discussed. Retarding the target combustion phasing by two degrees saw a 330 K drop in compressed charge temperature and a quadrupled reduction of peak NO emitted. Peak NO₂ emission reduced three times on account of the same. However, an increase in CO emission was observed when the combustion phasing was advanced. An integrated engine, emissions and aftertreatment models platform was used for this study. A low-temperature combustion (LTC) cylinder model was linked to serve the purpose of studying homogeneous charge compression ignition (HCCI) operation. Control over combustion phasing was made possible by linking a previously developed model-based controller to the integrated model.