Model-based turbocharger control - a common approach for SI and DI engines
In this master’s thesis, a turbine model and a common control structure for the
turbocharger for SI and CI-engines is developed. To design the control structure,
simulations are done on an existing diesel engine model with VGT. In order to
be able to make simulations for engines with a wastegated turbine, the model is
extended to include mass flow and turbine efficiency for that configuration. The
developed model has a mean absolute relative error of 3.6 % for the turbine mass
flow and 7.4 % for the turbine efficiency. The aim was to control the intake manifold
pressure with good transients and to use the same control structure for VGT
and wastegate. By using a common structure, development and calibration time
can be reduced. The non-linearities have been reduced by using an inverted turbine
model in the control structure, which consists of a PI-controller with feedforward.
The controller can be tuned to give a fast response for CI engines and a slower
response but with less overshoot for SI engines, which is preferable.
Erik Lindén and David Elofsson
Senast uppdaterad: 2021-11-10