Cycle-by-Cycle Optimization of the Combustion during Transient Engine Operation

Abstract In order to balance emissions accurately during highly transient engine operation, novel approaches of diesel engine control must achieve an appropriate interplay of the cycle-by-cycle fuel injection, i.e. the start position and mass of each fuel injection pulse, and the air system control scheme. Accordingly, this paper proposes a control concept that adjusts the fuel injection parameters as manipulated variables in dependence of the transient air system dynamics. The approach is based on a cylinder model that predicts the emissions and torque by means of physical and Gaussian Process Regression models. Fuel injection adjustments are determined by numerical optimization to minimize emissions while providing the desired engine torque. The optimization also considers the uncertainty of the emission predictions. This controller is tested by a high fidelity reference engine model which is also briefly introduced. It combines the cylinder description with a 1-dimensional air system model built up in the simulation environment GT-suite. The entire engine model is parametrized and validated using test-bench measurements.