A comprehensive decoupling control method for gasoline HCCI combustion

Homogeneous charge compression ignition (HCCI) engine can be regarded as a multi-input multi-output (MIMO) system with cross-coupling and large dynamic uncertainties. In this paper, a comprehensive decoupling control method is proposed for a port-fuel injected stoichiometric HCCI engine equipped with variable valve actuation (VVA). A control-oriented statistical model is developed for static decoupling with intake valve closing (IVC), exhaust valve closing (EVC), and injected fuel quantity as inputs and combustion timing (CA50), gross indicated mean effective pressure (Gross IMEP) and air-fuel ratio (Lambda) as outputs. All the remaining un-modeled and un-decoupled cross-coupling and disturbances, internal and external, are estimated and mitigated in real time by active disturbance rejection control (ADRC), which acts as dynamic decoupling. To compensate for the time-variant valve train dynamics, an adaptive valve train dynamic compensation method is added and proves to work well. Finally, this controller is tested and compared with another similar one, which only replaces ADRCs with Proportional-Integral-Differential (PID) controllers on a Simulink/GT-power platform. Initial simulation results the superiority of the proposed solution in decoupling performance and robustness to engine operating condition variations, making it a strong candidate in the competing solutions.