Qingyuan Tan

Exhaust gas recirculation control through extremum seeking in a Low Temperature Combustion diesel engine

Low Temperature Combustion (LTC) modes in diesel engines are characterized by enhanced homogeneity of the combustion mixture resulting from a longer ignition delay when compared to conventional diesel combustion. This is enabled by charge density and dilution control, coupled with modulation of fuel injection parameters. Charge dilution is achieved by exhaust gas recirculation (EGR), while turbocharging enables in-cylinder charge density increase. The coupling between the EGR and turbocharging systems exhibits highly non-linear interactions in the engine air-path. In this work, a two part control strategy is investigated for the regulation of EGR and turbocharging in a diesel engine to direct the combustion to approach LTC without largely compromising the combustion efficiency. Firstly, a simplified engine air-path model is presented that emphasizes the correlation between the intake oxygen concentration ([O2-int]) set-point and the individual EGR and turbocharging actuator set-points at different engine operating points. Thereafter, experimental data is presented that highlights the sensitivity of engine-out NOx emissions and combustion efficiency against the [O2-int]. Secondly, an extremum seeking (ES) algorithm is used to determine the [O2-int] set-point using a cost function that results in a desirable emission and combustion performance. Finally, the coordinated execution of the ES algorithm and the air-path model to generate the air-path actuator set-points is discussed.

Nonlinear model reference observer design for feedback control of a low temperature combustion diesel engine

A nonlinear observer design is proposed for fuel delivery control of a low temperature combustion (LTC) diesel engine. First, a nonlinear engine model, combining the continuous time gas exchange and the event-based closed cycle processes, is presented for the diesel engine. Secondly, an optimization routine based on the extremum seeking scheme is implemented for online observer calibration on a 10 engine rotations basis to follow the engine sensor outputs. The extremum seeking algorithm efficiently minimizes the observer error, demonstrated by simulation results with embedded engine test data. Finally, a feedback control architecture is proposed based on the observer trajectory as the engine feedback.

Diesel Engine Fuel Injection Control Using a Model-Guided Extremum-Seeking Method

Diesel engine fuel injection control is presented as a feedback based online optimization problem. Extremum seeking (ES) approach is used to address the online optimization formulation. The cost function is synthesized from extensive experimental investigations such that the indicated thermal efficiency of the engine is maximized while minimizing the NOx emissions under external boundary conditions. Knowledge of the physical combustion and emission formation process based on a pre-calibrated non-linear engine model output is used to determine the ES initial control input to minimize the seeking time. The control is demonstrated on a hardware-in-the-loop engine simulator bench.Copyright

Wiener structure based model identification for an electronic throttle body

A model of Wiener structure is presented in this work to represent the characteristics of an electronic throttle body. The proposed model consists of a linear submodel, which is used to capture the electric motor dynamics of the throttle body, and a nonlinear submodel, which is used to represent the nonlinearities in friction and spring torques. The relationship between the proposed model and the physics based model is analyzed. Model parameter identification and validation are demonstrated using open-loop measurement data.