Extremum seeking tuning of an experimental HCCI engine combustion timing controller

Homogenous charge compression ignition (HCCI) engines have the benefit of high efficiency with low emissions, at the price of not having a direct means to control the combustion timing. This fact makes combustion timing control of an HCCI engine more difficult than in spark ignition and diesel engines. While PID controllers have proved effective at isolated operating points, gain scheduling is needed to cover the entire range of operation. We use extremum seeking to tune the combustion timing controller of an experimental HCCI engine. Extremum seeking is found to be a useful tool for quick determination of optimal controller parameters. Such a tool allows for HCCI combustion timing controllers to be tuned over the range of operating points.