Methods and systems for controlling combustion performance of an engine during recompression HCCI combustion are provided. The method includes regulating a valve actuation timing and a fuel injection timing to cause a combustion phasing of at least one cylinder of the engine to approach a target combustion phasing, and estimating current combustion state information based on the combustion phasing. The current combustion state information includes at least one of a temperature, a pressure, and a pre-combustion charge composition associated with the at least one cylinder. The method further includes determining a target fuel injection amount, and determining whether the target fuel injection amount would require actuator settings that violate predetermined constraints in order to cause the combustion phasing to approach the target combustion phasing. A fuel injection amount is adjusted when the target fuel injection amount would require actuator settings that violate the predetermined constraints.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was made with Government support under grant No. DE-EE0003533 awarded by the Department of Energy. The Government has certain rights in this invention.