Optimal control of a diesel engine with VGT and EGR
To fulfill todays requirements on emissions from engines, SCANIA has
developed an engine with EGR (Exhaust Gas Recirculation) and VGT
(Variable Geometry Turbine). This gives two extra control signals to
take into consideration. Open loop optimal control is used to
investigate how these two actuators should be controlled to minimize
emissions and fuel consumption. A cost function, consisting of the
errors between the most important variables and their set points, has
been used in the minimization. The variables are the torque, the EGR
mass fraction, the oxygen/fuel ratio and the pumping losses. From
studies of the two control signals in different transients in the
engine, information of how to control the VGT and EGR in the optimal
way is found. The result from the optimal control has been compared
with a PID simulation and has showed a better way to control the
signals. The mayor reason why the optimal control is better than a PID
controller is the ability to use future values from the transients.
Jonas Olsson and Markus Welander
2006

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Last updated: 2021-11-10