Extending HCCI Low Load Operation Using Chaos Prediction and Feedback Control

Homogenous Charge Compression Ignition (HCCI) is a promising technology that offers high fuel economy and low oxides of nitrogen and particulate emission for automotive and stationary engines. A significant challenge with HCCI is the large number of partial burn/misfire cycles within the lean operation and the control of the combustion phasing. A detailed experimental and modeling investigation into the patterns of HCCI ignition timing and control based on deterministic structure of data points in HCCI combustion to reduce the high cyclic variations for operating conditions near misfire and to extend the HCCI operating range is the focus of this thesis.;Nonlinear dynamics and chaos theory applied to a wide range of engine operating conditions show that unstable operation of HCCI with higher cyclic variations with a non-Gaussian distribution is observed near the partial burn and misfire region of the engine. In order to predict and control the ignition timing in the partial burn region of HCCI, the temporal dynamics of cyclic variation in HCCI engine near misfire is analyzed using chaotic theory methods. Closed loop ignition timing control is used to reduce cyclic combustion variations for an unstable operating range of the engine near misfire using fuel octane as the control input.