A Short Review of Earlier Work in the Engine Control Group (ECG)
The ECG at IAU and LfE, DTU.
The Engine Control Group (ECG) at DTU is an strongly integrated
interdisciplinary team lead by two researchers who have been
cooperating for more than 14 years: Associate Professors Elbert
Hendricks, Institute for Automation (IAU), and Spencer C.
Sorenson, Laboratory for Energetics (LfE). Extensive equipment,
instrumentation, work shop and dynamometer facilities are
available for the ECG at IAU and LfE.
In projects which involve the use of adaptive control systems
and/or advanced numerical methods, Prof. Niels Poulsen of the
Institute for Mathematical Modelling (IMM) and Prof. Niels Houbak
(LfE) join the ECG. In work involving the design and
construction of semiconductor sensors, a long standing (12 years)
cooperative effort has been in effect with Prof. Otto Leistiko,
Director of the Microelectronic Center (DTU) of DTU. So far
about 18 Masters Thesis and Ph. D. Dissertation projects have
been carried out in the ECG, involving more that 30 students.
Historical Background
Work at the Technical University of Denmark (DTU) began in 1984 and was first concerned with the modelling af large, turbocharged, two stroke diesel engines. The main thrust of this work was arrive at a minimal dynamic model of the engine which was as physical as possible. This work was initially carried out in coorperation with Basic Research Department, M.A.N.-B&W Diesel A/S. This work resulted in an accurate model which was both physically based and very compact, while at the same time having very good global accuracy. Later investigations focused on using the model for control purposes, and among other things, minimum energy control. This work has been descriped in several publications, of which five are referenced here [1]-[5]. The model is currently in use at the M.A.N-B&W Diesel A/S for predicting transient engine/turbocharger behavior with various loads (ship propellers, generators, clutches, etc.) and with various engine controllers.
The success which had been achieved in modelling large diesel engines prompted work on small diesel and spark ignition (SI) engines. This work started in 1987 with support from the Danish Ministry of Energy and several research grants from an international automotive manufacturer, Ford Motor Co.. The aim of the work was, as before, to develop a minimal, physically based SI engine model and later to apply it to the study of control systems. This work has also been successful and has resulted in a number of publications, both of the engine model and subsequent model based control studies [6], [7], [8], [31].
The main goal of the SI control system investigations has been to study conventional and advanced controllers for transient and steady state air/fuel ratio control as well as idle speed and general engine speed control. A secondary goal has been to develop accurate emissions models. The published work on advanced control systems is concerned with the construction of nonlinear observers (Constant Gain Extended Kalman Filters, CGEKFs) for engines and nonlinear fuel film dynamics compensators. Several examples of the conventional control studies are referenced here: [11], [13], [24], [28], [30] and another group on advanced controllers: [14], [16], [18], [19], [20], [21], [22], [25], [27], [28], [34], [34], [35], [36], [38].
Current work at DTU is aimed at improving the already developed engine model and CGEKF observers, constructing other advanced controllers with an an eye towards A/B comparisons and adapting these strategies for lean burn operation. The engine models are being made more physical with fewer fitting parameters. Adaptive parameter estimation and robust control schemes are under development to avoid the large calibration costs inherent in model based strategies. Sliding mode observers and controllers are now being compared with the CGEKF observers and conventional controllers. Drive-By-Wire systems are also under investigation for combined stoichiometric and lean burn operation. Finally superordinated (as opposed to subordinated) minimum energy controllers are to be studied as a part of the Drive-By-Wire systems.
Work at the Technical University of Denmark was recently recognized by the award of a Ford Grant for research in the engine control area for three years. This work is to be concerned with advanced observer types which can be used with arbitrary air mass flow related sensors of various types. The preliminary work in this new area has already been published [34], [35].
