Off- and On-Line Identification of Maps Applied to the Gas Path in Diesel Engines
Maps or look-up tables are frequently used in engine control systems,
and can be of dimension one or higher. Their use is often to describe
stationary phenomena such as sensor characteristics or engine
performance parameters like volumetric efficiency. Aging can slowly
change the behavior, which can be manifested as a bias, and it can be
necessary to adapt the maps. Methods for bias compensation and on-line
map adaptation using extended Kalman filters are investigated and
discussed. Key properties of the approach are ways of handling
component aging, varying measurement quality, as well as operating
point dependent model quality. Handling covariance growth on locally
unobservable modes, which is an inherent property of the map
adaptation problem, is also important and this is solved for the
Kalman filter. The method is applicable to off-line calibration of
maps where the only requirement of the data is that the entire
operating region of the system is covered, i.e. no special calibration
cycles are required. Two truck engine applications are evaluated, one
where a 1-D air mass-flow sensor adaptation map is estimated, and one
where a 2-D volumetric efficiency map is adapted, both during a
European transient cycle. An evaluation on experimental data shows
that the method estimates a map, describing the sensor error, on a
measurement sequence not specially designed for adaptation.
Erik Höckerdal, Lars Eriksson and Erik Frisk
Springer Verlag,
Identification for Automotive Systems, In Lecture Notes in Control and Information Sciences. Editors: D. Alberer, H. Hjalmarsson
and L. del Re.,
2012
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