The Study About Air Path System Control For Diesel Engine Based On Predictive Control

The environment in cylinder and injection parameters is the key which determinesengine combustion modes, when intake valve is closing. Because of the use of Common-Rail Injection System, controlling injection parameters, such as fuel injectionquantity, injection timing, injection pressure, injection methods, is easy. In contrast, due tothe effect about inlet conditions, the total amount of intake and exhaust, residual gas incylinder and operating conditions, controlling the environment in cylinder is more difficult.Instead of controlling the environment in cylinder, controlling the state of the intakemanifold when the intake valve has been closed is better choice. The state of the intakemanifold determines the actual state of gas in cylinder. It requires the establishment ofa complex control system for air path. The use of a complex air-path adjusts desired intakemanifold temperature, pressure, and oxygen mass fraction at IVC. Not only could thishasten the implementation of advanced combustion modes but it also stretches thepossibilities for combustion mode switching.This thesis presents a control design using exhaust gas recirculation (EGR) and variablegeometry turbo charging (VGT), installed on a diesel engine, to adjust intake pressure, andoxygen mass fraction. The model of the complex air path has been established in theGT-POWER. Dynamic matrix control algorithm is used for controller design. The massflow observer and mass flow controller about EGR has been designed, and the Performance hasbeen verified. The corresponding control effect has been obtained by using the coordinatedsimulation experiment of GT-POWER and MATLAB/SIMULINK.Simulation results show that the algorithm has achieved control purposes. The intakepressure and oxygen mass fraction is well regulated. The control accuracy is good in steadyconditions. This method can provide a reference for the next study.