Smooth switching between 2-stroke and 4-stroke modes of HCCI operation

Switching between 2-stroke and 4-stroke modes of homogeneous charge compression ignition (HCCI) operation is a promising method for extending load range of HCCI engine. Switching between the two modes introduces disturbances into the system resulting in significant tracking errors. We propose an architecture for control system and a method for calculation of control inputs which minimize the tracking errors during switching. Proposed method produces inputs for engine valve timings which insure smooth transitions between the two HCCI modes under a varying engine load. The method uses techniques from the theory of system identification and the theory of optimal control.