Constrained Nonlinear Predictive Control of Gasoline Low-Temperature Combustion

Constrained Nonlinear Predictive Control of Gasoline Low-Temperature Combustion — Combustion of a gasoline fuel with a high amount of recirculated exhaust gas is increasingly gaining interest. Such in part load conditions, a low combustion peak temperature can be achieved, which yields lowest emissions but suffers from instabilities of the process and a highly nonlinear behavior. These properties make a closed-loop control a requirement for transient operation but also a challenge. The paper presents an innovative Nonlinear Model-based Predictive Controller (NMPC) for controlling the Indicated Mean Effective Pressure (IMEP) and Crank Angle of 50% burnt mass fraction (CA50) while accounting for constraints on the maximum pressure rise (dpmax). The implementation of the controller is presented in a framework for Rapid Control Prototyping (RCP) enabling the user to set up a complex controller for transient operation in a short time frame. The ability of the approach is proved by application to the real engine. 628 Oil & Gas Science and Technology – Rev. IFP Energies nouvelles, Vol. 66 (2011), No. 4 Definitions, Acronyms, Abbreviations BDCGE Bottom Dead Center in the Gas Exchange cycle BDCHP Bottom Dead Center in the High Pressure cycle CA Crank Angle CA50 Crank Angle of 50% burnt mass CAI Controlled Auto-Ignition CCR Combustion Chamber Recirculation dpmax Maximum pressure rise per degree Crank Angle of a whole cycle ED Energizing Duration EE End of Energizing EKF Extended Kalman Filter EMVT Electro-Mechanical Valve Train EVC Valve event Exhaust Valve Close EVO Valve event Exhaust Valve Open HIL Hardware-In-the-Loop IMEP Indicated Mean Effective Pressure IVC Valve event Intake Valve Close IVO Valve event Intake Valve Open MIL Model-In-the-Loop MIMO Multiple-Input-Multiple-Output MISO Multiple-Input-Single-Output MLP Multi-Layer-Perceptron MPC Model-based Predictive Controller nrev Revolution speed NMPC Nonlinear Model-based Predictive Controller NNSS(IF) Neural Network StateSpace (Innovations Form) NOx Nitrogen Oxides NVH Noise, Vibration, and Harshness PID Proportional, Integral, Derivate controller RCP Rapid Control Prototyping RWTH Rheinisch Westfälische Technische Hochschule Aachen SSE Sum Squared Error Tair,in Temperature of the air in the intake manifold TCW,in Temperature of the coolant water before the engine Toil Temperature of the oil TDCGE Top Dead Center in the Gas Exchange cycle TDCHP Top Dead Center in the High Pressure cycle