Control of variable geometry turbocharged diesel engines for reduced emissions

An emission control problem for an automotive direct injected compression i gnition (diesel) engine equipped with exhaust gas recirculation (EGR) and a variable geometry turbocharger (VGT) is considered. The objective is to op erate the engine to-meet driver's torque demand and minimize NOx emissions while at the same time avoiding visible smoke generation. It is demonstrate d that the steady-state optimization of engine emissions results in operati ng points where EGR and VGT actuators are In effect redundant in their effe ct on the variables that most directly affect the emissions. A multivariabl e feedback controller is proposed which accounts for this actuator redundan cy, Furthermore, It coordinates the two actuators to fully utilize their jo int effect on engine emission performance. Experimental results confirm goo d response properties of the proposed controller.