System Identification of Homogenous Charge Compression Ignition (HCCI) Engine Dynamics

Homogeneous Charge Compression Ignition (HCCI) combustion lacksdirect ignition timing control, instead the auto ignition depends on the operatingcondition. Since auto ignition of a homogeneous mixture is very sensitive tooperating condition a fast combustion timing control is necessary for reliableoperation, the ignition timing control design requiring appropriate modelsand system output variables for its feedback design. This paper demonstratesthe use of system modeling and identification as a means to find modelsrelevant to the engine control. The identification methods used were varioussubspace-based methods. An LQG controller was designed based on the estimatedmodels and tested on a six-cylinder heavy duty engine running in HCCI operation.