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  • 101.
    Nilsson, Ylva
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Eriksson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Gunnarsson, Martin
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    A Model for Fuel Optimal Control of a Spark-Ignited Variable Compression Engine2006Conference paper (Refereed)
  • 102.
    Nilsson, Ylva
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Eriksson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Gunnarsson, Martin
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Modeling for Fuel Optimal Control of SI VCR Engines2006Conference paper (Refereed)
  • 103.
    Nilsson, Ylva
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering.
    Eriksson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Gunnarsson, Martin
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering.
    Torque modelling for optimising fuel economy in variable compression engines2008In: International Journal of Modelling, Identification and Control, ISSN 1746-6172, Vol. 3, no 3, p. 327-339Article in journal (Refereed)
    Abstract [en]

    Fuel optimal control of a variable compression engine is studied and it is shown that a crucial component is the model for the engine torque. A model for the produced work that captures the important effects of ignition and compression ratio is proposed and investigated. The main task for the model is to be a mean for determining the fuel optimal control signals, for each requested engine torque and speed. The contribution is a model suitable for finding this optimal combination. This model consists of well-known components, and the novelty lies in the compilation and validation of the control-oriented efficiency model for a variable compression engine. The modelling and validation is performed on a multicylinder variable compression engine using two fuels with different octane rating. Despite the models simplicity, it describes the indicated work with good accuracy, and suits its purpose of finding optimal control signals. In the evaluation, it is shown that a fuel optimal controller based on the proposed model captures the optimal IMEP to within 1.2%. This corresponds to a loss in engine efficiency that is in the range of 0.5% units or less. Copyright © 2008, Inderscience Publishers.

  • 104.
    Sciarretta, A.
    et al.
    IFP Energies Nouvelles, France .
    Serrao, L.
    Dana Corporation, Italy.
    Dewangan, P.C.
    IFP Energies Nouvelles, France; IFP School, France .
    Tona, P.
    IFP Energies Nouvelles, France .
    Bergshoeff, E.N. D.
    TU Eindhoven, Netherlands.
    Bordons, C.
    University of Seville, Spain .
    Charmpa, L.
    IFP Sch, France Continental, France .
    Elbert, Ph.
    ETH Zurich, Switzerland.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Hofman, T.
    TU Eindhoven, Netherlands .
    Hubacher, M.
    TU Eindhoven, Netherlands .
    Isenegger, R.
    TU Eindhoven, Netherlands .
    Lacandia, F.
    Ohio State University, USA.
    Laveau, A.
    IFP School, France.
    Li, H.
    IFP School, France.
    Marcos, D.
    University of Seville, Spain .
    Nueesch, T.
    ETH Zurich, Switzerland.
    Onori, S.
    Ohio State University, USA .
    Pisu, P.
    Clemson University, USA .
    Rios, J.
    Clemson University, USA .
    Silvas, E.
    TU Eindhoven, Netherlands .
    Sivertsson, Martin
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Tribioli, L.
    Ohio State University, USA .
    van der Hoeven, A.-J.
    TU Eindhoven, Netherlands .
    Wu, M.
    IFP School, France.
    A control benchmark on the energy management of a plug-in hybrid electric vehicle2014In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 29, p. 287-298Article in journal (Refereed)
    Abstract [en]

    A benchmark control problem was developed for a special session of the IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling (E-COSM 12), held in Rueil-Malmaison, France, in October 2012. The online energy management of a plug-in hybrid-electric vehicle was to be developed by the benchmark participants. The simulator, provided by the benchmark organizers, implements a model of the GM Voltec powertrain. Each solution was evaluated according to several metrics, comprising of energy and fuel economy on two driving profiles unknown to the participants, acceleration and braking performance, computational performance. The nine solutions received are analyzed in terms of the control technique adopted (heuristic rule-based energy management vs. equivalent consumption minimization strategies, ECMS), battery discharge strategy (charge depleting-charge sustaining vs. blended mode), ECMS implementation (vector-based vs. map-based), ways to improve the implementation and improve the computational performance. The solution having achieved the best combined score is compared with a global optimal solution calculated offline using the Pontryagins minimum principle-derived optimization tool HOT.

  • 105.
    Shitahun, Alachew
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Ruge, Vitalij
    University of Applied Sciences, Bielefeld, Germany.
    Gebremedhin, Mahder
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Bachmann, Bernhard
    University of Applied Sciences, Bielefeld, Germany.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Andersson, Joel
    Diehl, Moritz
    Engineering Center (OPTEC), Leuven, Belgium.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Model-Based Dynamic Optimization with OpenModelica and CasADi2013In: IFAC-AAC 2013, 2013, p. 446-451Conference paper (Refereed)
    Abstract [en]

    This paper demonstrates model-based dynamic optimization through the coupling of two open source tools: OpenModelica, which is a Modelica-based modeling and simulation platform, and CasADi, a framework for numerical optimization. The coupling uses a standardized XML format for exchange of differential-algebraic equations (DAE) models. OpenModelica supports export of models written in Modelica and the optimization language extension using this XML format, while CasADi supports import of models represented in this format. This allows users to define optimal control problems (OCP) using Modelica and optimization language specification, and solve the underlying model formulation using a range of optimization methods, including direct collocation and direct multiple shooting. The proposed solution has been tested on several industrially relevant optimal control problems, including a diesel-electric power train.

  • 106.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    An Optimal Control Benchmark: Transient Optimization of a Diesel-Electric Powertrain2014In: Proceedings of the 55th International Conference on Simulation and Modelling (SIMS 55), 21-22 October, Modelling, Simulation and Optimization / [ed] Alireza Rezania Kolai, Kim Sørensen & Mads Pagh Nielsen, Linköping University Electronic Press, 2014, p. 59-63Conference paper (Refereed)
    Abstract [en]

    An optimal control benchmark is presented and discussed. The benchmark is optimal transient control of a nonlinear four state three control model of a diesel-electric powertrain and constructed in such a manner that it is available in several versions to be of interest for developers of optimal control tools at different levels of development. This includes with and without time as a parameter as well as with and without time varying constraints.

  • 107.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Design and Evaluation of Energy Management using Map-Based ECMS for the PHEV Benchmark2015In: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 70, no 1, p. 195-211Article in journal (Refereed)
    Abstract [en]

    Plug-in Hybrid Electric Vehicles (PHEV) provide a promising way of achieving the benefits of the electric vehicle without being limited by the electric range, but they increase the importance of the supervisory control to fully utilize the potential of the powertrain. The winning contribution in the PHEV Benchmark organized by IFP Energies nouvelles is described and evaluated. The control is an adaptive strategy based on a map-based Equivalent Consumption Minimization Strategy (ECMS) approach, developed and implemented in the simulator provided for the PHEV Benchmark. The implemented control strives to be as blended as possible, whilst still ensuring that all electric energy is used in the driving mission. The controller is adaptive to reduce the importance of correct initial values, but since the initial values affect the consumption, a method is developed to estimate the optimal initial value for the controller based on driving cycle information. This works well for most driving cycles with promising consumption results. The controller performs well in the benchmark; however, the driving cycles used show potential for improvement. A robustness built into the controller affects the consumption more than necessary, and in the case of altitude variations the control does not make use of all the energy available. The control is therefore extended to also make use of topography information that could be provided by a GPS which shows a potential further decrease in fuel consumption.

  • 108.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Generator Effects on the Optimal Control of a Power Assisted Diesel-Electric Powertrain2013In: IEEE VPPC 2013 – The 9th IEEE Vehicle Power and Propulsion Conference, Institute of Electrical and Electronics Engineers (IEEE), 2013Conference paper (Refereed)
    Abstract [en]

    Optimal control of a diesel-electric powertrain in transient operation is studied. The attention is on how generator limits affect the solution, as well as how the addition of a small energy storage can assist in the transients. Two different types of problems are solved, minimum fuel and minimum time, with different generator limits as well as with and without an extra energy storage. In the optimization both the output power and engine speed are free variables. For this aim a 4-state mean value engine model is used together with models for the generator and energy storage losses. The considered transients are steps from idle to target power with different amounts of freedom, defined as requirements on produced energy, before the requested power has to be met. For minimum fuel transients the energy storage remains virtually unused for all requested energies, for minimum time it does not. The generator limits are found to have the biggest impact on the fuel economy, whereas an energy storage could significantly reduce the response time.

  • 109.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Model and discretization impact on oscillatory optimal control for a diesel-electric powertrain2015In: 4th IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling E-COSM 2015 Columbus, Ohio, USA, 23-26 August 2015, Elsevier, 2015, Vol. 48(15), p. 66-71Conference paper (Refereed)
    Abstract [en]

    A mean value engine model is used to study optimal control of a diesel-electric powertrain. The resulting optimal controls are shown to be highly oscillating for certain operating points, raising the question whether this is an artifact of discretization, modeling choices or a phenomenon available in real engines. Several model extensions are investigated and their corresponding optimal control trajectories are studied. It is shown that the oscillating controls cannot be explained by the implemented extensions to the previously published model, nor by the discretization, showing that for certain operating points the optimal solution is periodic.

  • 110.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Modeling for Optimal Control: A Validated Diesel-Electric Powertrain Model2014In: Proceedings of the 55th Conference on Simulation and Modelling (SIMS 55), Modelling, Simulation and Optimization, 21-22 October 2014, Aalborg, Denmark / [ed] Alireza Rezania Kolai, Kim Sørensen & Mads Pagh Nielsen, Linköping: Linköping University Electronic Press, 2014, p. 49-58Conference paper (Refereed)
    Abstract [en]

    An optimal control ready model of a diesel-electric powertrain is developed,validated and provided to the research community. The aim ofthe model is to facilitate studies of the transient control of diesel-electricpowertrains and also to provide a model for developers of optimizationtools. The resulting model is a four state three control mean valueengine model that captures the significant nonlinearity of the diesel engine, while still being continuously differentiable.

  • 111.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Optimal and real-time control potential of a diesel-electric powertrain2014In: Proceedings of the 19th World CongressThe International Federation of Automatic ControlCape Town, South Africa. August 24-29, 2014 / [ed] Edward Boje and Xiaohua Xia, Cape Town: International Federation of Automatic Control , 2014, Vol. 19, p. 4825-4830Conference paper (Refereed)
    Abstract [en]

    Real-time control strategies and their performance related to the optimal control trajectories for a diesel-electric powertrain in transient operation are studied. The considered transients are steps from idle to target power. A non-linear four state-three input mean value engine model, incorporating the important turbocharger dynamics, is used for this study. The strategies are implemented using the SAE J1939-standard for engine control and evaluated compared to both the optimal solution and the solution when the engine is restricted to follow its stationary optimal line. It is shown that with the control parameters tuned for a specific criteria both engine control strategies in the SAE J1939-standard, speed control and load control, can achieve almost optimal results, where engine load controlled shows a better trade-off between fuel economy and duration. The controllers are then extended and it is shown that it is possible to control the powertrain in a close to optimal way using the SAE J1939-standard, both with the engine speed and load controlled. However the mode where the engine is load controlled is seen to be more robust.

  • 112.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Optimal Short Driving Mission Control for a Diesel-Electric Powertrain2012In: IEEE VPPC 2012 -- The 8th IEEE Vehicle Power and Propulsion Conference, IEEE , 2012, p. 413-418Conference paper (Refereed)
    Abstract [en]

    Time and fuel optimal control for a diesel-electric powertrain in transient operation is studied using a four state, three controls non-linear mean value engine model. In the studied transients the engine starts at idle and stops when the generated energy fulfills the driving mission requirement. During the driving mission both the engine speed and output power are allowed to vary, but with a constraint on power. Two strategiesare then developed and evaluated. One where the driving mission is optimized with the generator power considered a free variable,and a second strategy where the accelerating phase of the transient is first optimized and then the optimal controls fora fixed generator power are used. The time optimal control is shown to be almost as fuel efficient as the fuel optimal controleven though the gain in time is large. The time optimal control also has the advantage of using constant power output, making itsimple and easily implementable, whilst the fuel optimal control is more complex and changes with the length of the driving mission.

  • 113.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Optimal stationary control of diesel engines using periodic control2017In: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering, ISSN 0954-4070, E-ISSN 2041-2991, Vol. 231, no 4, p. 457-475Article in journal (Refereed)
    Abstract [en]

    Measurements and optimal control are used to study whether the fuel economy of a diesel engine can be improved through periodic control of the wastegate, illustrating how modern optimal control tools can be used to identify non-trivial solutions that can improve performance. The measurements show that the pumping torque of the engine is changed when the wastegate is controlled in a periodic manner versus stationary even if the mean position is the same. If this decreases the fuel consumption or not is seen to be frequency and operating point dependent. The measurements indicate that the phenomenon occurs in the time scales capturable by mean value engine models (MVEM). The operating points are further analyzed using a MVEM and optimal control. It is shown that whether the optimal solution exhibits periodic oscillations or not is operating point dependent, but is not due to the instantaneous nature of the controls. Even if an actuator model is added the oscillations persist for reasonable time constants, the frequency of the oscillations is however affected. Further it is shown that the periodic control can be predicted by optimal periodic control theory and that the frequency of the control affects the resulting efficiency.

  • 114.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Optimal Step Responses in Diesel-Electric Systems2012In: Mechatronics'12 -- The 13th Mechatronics Forum International Conference, 2012Conference paper (Refereed)
    Abstract [en]

    A non-linear four state-three input mean value engine model, incorporating the important turbocharger dynamics,is used to study optimal control of a diesel-electric powertrain during transients. The optimization is conducted for two differentcriteria, both time and fuel optimal control, and both engine speed and output power are considered free variables in theoptimization. The transients considered are steps from idle to a target power and the results of the optimization show thatthe solutions can be divided into two categories, depending on requested power. The resulting control strategies are also seento be valid for other initial conditions than idle. For steps to high power the controls for both criteria follow a similarstructure, a structure given by the maximum torque line and the smoke-limiter. The main difference between fuel and timeoptimal control is the end operating point, and how this is approached. The fuel optimal control builds more kinetic energyin the turbocharger, reducing the necessary amount of kinetic energy in the system to produce the requested power. It is foundthat the fact that it does not approach the fuel optimal operating point relates to the amount of produced energy required to getthere. For steps to low output powers the optimal controls deal with the turbocharger dynamics in a fundamentally differentway.

  • 115.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Optimal transient control and effects of a small energy storage for a diesel-electric powertrain2013In: 7th IFAC Symposium on Advances in Automotive Control, 2013 / [ed] Taketoshi Kawabe, International Federation of Automatic Control , 2013, p. 818-823Conference paper (Refereed)
    Abstract [en]

    Optimal control of a diesel-electric powertrain in transient operation is studied. The attention is on how generator limits affect the solution, as well as how the addition of a small energy storage can assist in the transients. Two different types of problems are solved, minimum fuel and minimum time, with different generator limits as well as with and without an extra energy storage. In the optimization both the output power and engine speed are free variables. For this aim a 4-state mean value engine model is used together with models for the generator and energy storage losses. The considered transients are steps from idle to target power with different amounts of freedom, defined as requirements on produced energy, before the requested power has to be met. For minimum fuel transients the energy storage remains virtually unused for all requested energies, for minimum time it does not. The generator limits are found to have the biggest impact on the fuel economy, whereas an energy storage could significantly reduce the response time.

  • 116.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Optimal Transient Control Trajectories in Diesel-Electric Systems-Part I: Modeling, Problem Formulation, and Engine Properties2015In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, no 2, article id 021601Article in journal (Refereed)
    Abstract [en]

    A nonlinear four state-three input mean value engine model (MVEM), incorporating the important turbocharger dynamics, is used to study optimal control of a diesel-electric powertrain during transients. The optimization is conducted for the two criteria, minimum time and fuel, where both engine speed and engine power are considered free variables in the optimization. First, steps from idle to a target power are studied and for steps to higher powers the controls for both criteria follow a similar structure, dictated by the maximum torque line and the smoke-limiter. The end operating point, and how it is approached is, however, different. Then, the power transients are extended to driving missions, defined as, that a certain power has to be met as well as a certain energy has to be produced. This is done both with fixed output profiles and with the output power being a free variable. The time optimal control follows the fixed output profile even when the output power is free. These solutions are found to be almost fuel optimal despite being substantially faster than the minimum fuel solution with variable output power. The discussed control strategies are also seen to hold for sequences of power and energy steps.

  • 117.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Optimal Transient Control Trajectories in Diesel-Electric Systems-Part II: Generator and Energy Storage Effects2015In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, no 2, article id 021602Article in journal (Refereed)
    Abstract [en]

    The effects of generator model and energy storage on the optimal control of a diesel-electric powertrain in transient operation are studied. Two different types of problems are solved, minimum fuel and minimum time, with different generator models and limits as well as with an extra energy storage. For this aim, a four-state mean value engine model (MVEM) is used together with models for the generator and energy storage losses. In the optimization both the engines output power and speed are free variables. The considered transients are steps from idle to target power with different amounts of freedom, defined as requirements on produced energy, before the requested power has to be met. The main characteristics are seen to be independent of generator model and limits; they, however, shift the peak efficiency regions and therefore the stationary points. For minimum fuel transients, the energy storage remains virtually unused for all requested energies, for minimum time it is used to reduce the response time. The generator limits are found to have the biggest impact on the fuel economy, whereas an energy storage could significantly reduce the response time. The possibility to reduce the response time is seen to hold for a large range of values of energy storage parameters. The minimum fuel solutions remain unaffected when changing the energy storage parameters, implying it is not beneficial to use an energy storage if fuel consumption is to be minimized. Close to the minimum time solution, the fuel consumption with low required energy is quite sensitive to variations in duration, for larger energies it is not. Near the minimum fuel solution changes in duration have only minor effects on the fuel consumption.

  • 118.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Time and Fuel Optimal Power Response of a Diesel-Electric Powertrain2012In: E-COSM'12 -- IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling, 2012, p. 262-269Conference paper (Refereed)
    Abstract [en]

    Optimal control policies for a diesel-electric powertrain in transient operation are studied. In order to fully utilize the extra degree of freedom available in a diesel-electric powertrain, compared to a conventional powertrain, the engine-speed is allowed to vary freely.The considered transients are steps from idle to target power. A non-linear four state-three input mean value engine model, incorporating the important turbocharger dynamics, is used for this study. The study is conducted for two dierent criteria, fuel optimal control and time optimalcontrol. The results from the optimization show that the optimal controls for each criteria can be divided into two categories, one for high requested powers and one for low requested powers. For high power transients the controls for both criteria follow a similar structure, a structure givenby the maximum torque line and the smoke-limiter. The main dierence between the criteria is the end point and how it is approached. The fuel optimal control builds more kinetic energy in the turbocharger, reducing the necessary amount of kinetic energy in the system to producethe requested power. For low power transients the optimal controls deal with the turbocharger dynamics in a fundamentally dierent way.

  • 119.
    Sivertsson, Martin
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Sundström, Christofer
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Adaptive Control of a Hybrid Powertrain with Map-based ECMS2011In: Proceedings of the 18th IFAC World Congress, 2011 / [ed] Sergio Bittanti, Angelo Cenedese, Sandro Zampieri, 2011, p. 2949-2954Conference paper (Refereed)
    Abstract [en]

    To fully utilize the fuel reduction potential of a hybrid powertrain requires a careful design of the energy management control algorithms. Here a controller is created using mapbased equivalent consumption minimization strategy and implemented to function without any knowledge of the future driving mission. The optimal torque distribution is calculated oine and stored in tables. Despite only considering stationary operating conditions and average battery parameters, the result is close to that of deterministic dynamic programming. Eects of making the discretization of the tables sparser are also studied and found to have only minor eects on the fuel consumption. The controller optimizes the torque distribution for the current gear as well as assists the driver by recommending the gear that would give the lowest consumption. Two ways of adapting the control according to the battery state of charge are proposed and investigated. One of the adaptive strategies is experimentally evaluated and found to ensure charge sustenance despite poor initial values.

  • 120.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Co-Surge Detection and Control for Bi-Turbo Engines with Experimental Evaluation2013Conference paper (Refereed)
    Abstract [en]

    A V-type engine with a bi-turbocharger configuration utilizes the exhaust energy well which gives a fast torque response. An unwanted instability, called co-surge, can occur in such engines where the two interconnected compressors alternately go into flow reversals. If co-surge occurs, the control system must quell the oscillations with as little disturbance in engine torque as possible. A model of a bi-turbocharged engine is presented, combining a mean value engine model and a Moore-Greizer compressor model for surge. The model is validated against measurements on a vehicle dynamometer, showing that it captures the frequency and amplitude of the co-surge oscillation. The model is used to develop detection and control strategies for co-surge that rapidly returns the turbo to a stable operating point. Both simulations and experimental evaluation on the vehicle show that the developed strategies are successful in rapidly detecting and quelling co-surge. The selection of actuators is also studied. With no or small pressure drops over the throttle, it is necessary to use the bypass valves. However, for operating conditions with moderate and high pressure drops over the throttle, it is shown that it is sufficient to only open the throttle. This has the advantage, compared to opening the bypass valves, that it reduces the drop in boost pressure and thus reduces the drop in engine torque.

  • 121.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Co-Surge in Bi-Turbo Engines: Measurements, Analysis and Control2014In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 32, p. 113-122Article in journal (Refereed)
    Abstract [en]

    In parallel turbocharged V-engines, with two separate air paths connected before the throttle, an oscillation in the flow can occur.If the compressor operates close to the surge line, typically during low speed and high load, and a disturbance alters the massflow balance, the compressors can begin to alternately go into surge. This phenomenon is called co-surge and is unwanted due tohigh noise and risk for turbocharger destruction. Co-surge is measured on a test vehicle in a chassis dynamometer and the systemanalyzed and modeled using a mean value engine model. The investigation shows that the alternating compressor speeds have animportant role in the prolonged oscillation. A reconstruction of the negative flow from measurements is made and compared tosimulation results, showing similar amplitudes, and supports the model validation. A new co-surge detection algorithm is presented,suitable for a pair of sensors measuring either mass flow, boost pressure or turbo speed in the two air paths. Furthermore, a newcontroller is proposed that uses a model based feedforward for the throttle, together with wastegate actuation to force the compressorspeeds together and improve balance at the recovery point. This has shown to be sufficient with moderate to high pressure ratiosover the throttle, only for zero or very low pressure drop the use of bypass valves are necessary. The advantage of not opening thebypass valves is a smaller drop in boost pressure which also reduces the torque disturbance. The performance of the controller is evaluated both in simulation and in the test vehicle.

  • 122.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Effects of Pulsating Flow on Mass Flow Balance and Surge Margin in Parallel Turbocharged Engines2015In: Proceedings of the 56th Conference on Simulation and Modelling (SIMS 56), October, 7-9, 2015, Linköping University, Sweden, Linköping: Linköping University Electronic Press, 2015, Vol. 119, p. 15-20Conference paper (Refereed)
    Abstract [en]

    The paper extends a mean value model of a parallel turbocharged internal combustion engine with a crank angle resolved cylinder model. The result is a 0D engine model that includes the pulsating flow from the intake and exhaust valves. The model captures variations in turbo speed and pressure, and therefore variations in the compressor operating point, during an engine cycle. The model is used to study the effect of the pulsating flow on mass flow balance and surge margin in parallel turbocharged engines, where two compressors are connected to a common intake manifold. This configuration is harder to control compared to single turbocharged systems, since the compressors interact and can work against each other, resulting in co-surge. Even with equal average compressor speed and flow, the engine pulsations introduce an oscillation in the turbo speeds and mass flow over the engine cycle. This simulation study use the developed model to investigates how the engine pulsations effect the in cycle variation in compressor operating point and the sensitivity to co-surge. It also shows how a short circuit pipe between the two exhaust manifolds could increase surge margin at the expense of less available turbine energy.

  • 123.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Model-Based Throttle Control using Static Compensators and Pole Placement2011In: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 66, no 4, p. 717-727Article in journal (Refereed)
    Abstract [en]

    Model-Based Throttle Control using Static Compensators and Pole Placement - In modern spark ignited engines, the throttle is controlled by the Electronic Control Unit (ECU), which gives the ECU direct control of the air flow and thereby the engine torque. This puts high demands on the speed and accuracy of the controller that positions the throttle plate. The throttle control problem is complicated by two strong nonlinear effects, friction and limp-home torque. This paper proposes the use of two, simultaneously active, static compensators to counter these effects and approximately linearize the system. A PID controller is designed for the linearized system, where pole placement is applied to design the PD controller and a gain scheduled I-part is added for robustness against model errors. A systematic procedure for generating compensator and controller parameters from open loop experiments is also developed. The controller performance is evaluated both in simulation, on a throttle control benchmark problem, and experimentally. A robustness investigation pointed out that the limp-home position is an important parameter for the controller performance, this is emphasized by the deviations found in experiments. The proposed method for parameter identification achieves the desired accuracy.

  • 124.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Model-Based Throttle Control using StaticCompensators and IMC based PID-Design2009In: 2009 IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling. Paris, France., 2009Conference paper (Refereed)
    Abstract [en]

    In modern spark ignited engines the throttle is controlled by the electronic control unit (ECU) which gives the ECU direct control of the air flow and thereby the engine torque. This puts high demands on the speed and accuracy of the controller that positions the throttle plate. The throttle control problem is complicated by two strong nonlinear effects, friction and limp-home torque. This paper proposes the use of two, simultaneously active, static compensators to counter these effects and approximately linearize the system. A PID controller is designed for the linearized system, where IMC design is applied to design the PD controller and a gain scheduled I-part is added for robustness against model errors. A systematic procedure for generating compensator and controller parameters from open loop experiments is also developed. The controller performance is evaluated both in simulation, on a TC-benchmark problem, and experimentally. A robustness investigation pointed out that the limp-home position is an important parameter for the controller performance, this is emphasized by the deviations found in experiments. The proposed method for parameter identification achieves the desired accuracy.

  • 125.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Modeling and Control of Co-Surge in Bi-Turbo Engines2011In: Proceedings of the 18th IFAC World Congress, 2011 / [ed] Bittanti, Sergio, Cenedese, Angelo, Zampieri, Sandro, International Federation of Automatic Control (IFAC) , 2011, p. 13010-13015Conference paper (Refereed)
    Abstract [en]

    Using a bi-turbocharged configuration makes for better utilization of the exhaust energy and a faster torque response in V-type engines. A special surge phenomenon that should be avoided in bi-turbocharged engines is co-surge, which is when the two interconnected compressors alternately go into flow reversals. If co-surge should occur, the control system must be able to quell the oscillations with as little disturbance in torque as possible. This paper presents a model of a bi-turbocharged engine based on a Mean Value Engine Model that includes a More-Greizer compressor model for surge. The model is validated against measured data showing that it captures the frequency and amplitude of the co-surge oscillation. The effect of momentum conservation in the pipes is investigated by adding this feature to the control volumes before and after the compressor. This gives a slightly better mass flow shape with the drawback of increased simulation time, due to more states and a higher frequency content in the model. A sensitivity analysis is performed to investigate which model parameters have most influence on the co-surge behavior. It is shown that the largest influence comes from the turbocharger inertia, the volumes after the compressor and the ``zero mass flow pressure ratio'' during flow reversal in the compressor. The model is used to investigate principles for control strategies to detect and quell co-surge. The detection algorithm is evaluated on measured data.

  • 126.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Leufvén, Oskar
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Andersson, Per
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Wastegate Actuator Modeling and Model-Based Boost Pressure Control2009In: Proceedings of the 2009 IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling / [ed] Antonio Sciarretta and Paolino Tona, 2009, p. 87-94Conference paper (Refereed)
    Abstract [en]

    The torque response of an engine is important for driver acceptance. For turbocharged spark ignited (TCSI) engines this is tightly connected to the boost pressure control, which is usually achieved with a wastegate. A challenging scenario is when the throttle is fully open and the load is essentially controlled by the wastegate. First a model for the pneumatic wastegate actuator and air control solenoid is developed. The wastegate model consists of three submodels; the actuator pressure, the static position, and an additional position dynamics. A complete engine model is constructed by including the actuator model in a Mean Value Engine Model (MVEM) for a TCSI engine. This model describes the transient boost pressure response to steps in wastegate control inputs. The subsystems and complete MVEM are validated on an engine test bench and it explains the overshoot seen in the step responses. The model is used to study the system response and give insight into the dominating phenomena and it points out that the engine speed is important for the response. Further, for each speed it is sufficient to model the system as a second order linear system, that captures an overshoot. A controller consisting of a mapped feedforward loop and a gain scheduled feedback loop is developed together with a tuning method based on the IMC framework for the feedback loop. The controller and tuning method is shown to achieve the desired boost pressure behavior both on the complete MVEM and on real engines. The experimental validation is carried out both in an engine test cell and in a vehicle.

  • 127.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Lindell, Tobias
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Peyton Jones, James C.
    Villanova University, PA, USA.
    Spelina, Jill
    Villanova University, PA, USA.
    Frey, Jesse
    Villanova University, PA, USA.
    Tuning and experimental evaluation of a likelihood-based engine knock controller2013In: Proceedings of the 52nd IEEE Conference on Decision & Control, IEEE conference proceedings, 2013, p. 6849-6854Conference paper (Refereed)
    Abstract [en]

    A new likelihood-based stochastic knock controller, that achieves a significantly improved regulatory response relative to conventional strategies, while also maintaining a rapid transient response is presented. Up until now it has only been evaluated using simulations and the main contribution here is the implementation and validation of the knock controller on a five cylinder engine with variable compression ratio. Furthermore, an extension of the fast response strategy and a re-tuning of the controller is shown to improve performance. The controller is validated with respect to its robustness to changes in engine operating condition as well as compression ratio. The likelihood-based controller is demonstrated in engine tests and compared to a conventional controller and it is shown that it is able to operate closer to the knock limit with less variations in control action without increasing the risk of engine damage.

  • 128.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Leufvén, Oskar
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Criscuolo, Ivan
    University of Salerno, Italy .
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Modeling and validation of a boost pressure actuation system, for a series sequentially turbocharged SI engine2013In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 21, no 12, p. 1860-1870Article in journal (Refereed)
    Abstract [en]

    An actuation system for flexible control of an advanced turbocharging system is studied. It incorporates a vacuum pump and tank that are connected to pulse width modulation controlled vacuum valves. A methodology for modeling the entire boost pressure actuation system is developed. Emphasis is placed on developing component models that are easily identified from measured data, without the need for expensive measurements.The models have physical interpretations that enable handling of varying surrounding conditions.The component models and integrated system are evaluated on a two stage series sequential turbo system with three actuators having different characteristics.Several applications of the developed system model are presented, including a nonlinear compensator for voltage disturbance rejection where the performance of the compensator is demonstrated on an engine in a test cell. The applicability of the complete system model for control and diagnosis of the vacuum system is also discussed.

  • 129.
    Thomasson, Andreas
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Shi, Haoyun
    Sophia University, Japan.
    Lindell, Tobias
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Shen, Tielong
    Sophia University, Japan.
    Peyton Jones, James C.
    Villanova University, PA 19085 USA.
    Experimental Validation of a Likelihood-Based Stochastic Knock Controller2016In: IEEE Transactions on Control Systems Technology, ISSN 1063-6536, E-ISSN 1558-0865, Vol. 24, no 4, p. 1407-1418Article in journal (Refereed)
    Abstract [en]

    New likelihood-based stochastic knock controllers have the potential to deliver a significantly improved regulatory response relative to conventional strategies, while also maintaining a rapid transient response, but evaluation studies to date have been performed only in simulation. In this paper, an experimental validation of the new strategy is presented. To demonstrate the robustness of the method, the algorithm is implemented on two different engine platforms, using two different knock intensity metrics, and evaluated under different operating conditions. One of these platforms is a five-cylinder variable compression ratio engine, enabling the controller to be tested under different compression ratios, as well as different speed and load conditions. The regulatory and transient performance of the likelihood-based controller is assessed in a back-to-back comparison with a conventional knock controller and it is shown that the new controller is able to operate closer to the knock limit with less variation in control action without increasing the risk of engine damage.

  • 130.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Modeling of a Diesel Engine with Intake Throttle, VGT, and EGR2010Report (Other academic)
    Abstract [en]

    A mean value model of a diesel engine with intake throttle, VGT, and EGR is developed, parameterized, and validated. The intended model applications are system analysis, simulation, and development of model-based control systems. The goal is to construct a model that describes the gas flow dynamics including the dynamics in the intercooler pressure, manifold pressures, turbocharger, EGR, and actuators with few states in order to have short simulation times. An investigation of model complexity and descriptive capabilities is performed, resulting in a model that has only eleven states. To tune and validate the model, stationary and dynamic measurements have been performed in an engine laboratory at Scania CV AB. All the model parameters are estimated automatically using weighted least squares optimization of both the sub-models and the complete model.

    Dynamic measurements and simulations show that the proposed model captures the essential system properties, i.e. non-minimum phase behaviors, overshoots, and sign reversals. Validations of the entire model show that the mean value of all absolute relative errors for all measured outputs are equal to 7.4 %. A system analysis of the proposed model is performed in order to obtain insight into a VGT and EGR control problem where the goal is to control the performance variables oxygen fuel ratio λO and EGR-fraction xegr. Step responses over the entire operating region show that the channels VGT to λO, EGR to λO, and VGT to xegr have sign reversals.

  • 131.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Modeling of a Diesel Engine with VGT and EGR capturing Sign Reversal and Non-minimum Phase Behaviors2009Report (Other academic)
    Abstract [en]

    A mean value model of a diesel engine with VGT and EGR is developed and validated. The intended model applications are system analysis, simulation, and development of model-based control systems. The goal is to construct a model that describes the dynamics in the manifold pressures, turbocharger, EGR, and actuators with few states in order to have short simulation times. Therefore the model has only eight states: intake and exhaust manifold pressures, oxygen mass fraction in the intake and exhaust manifold, turbocharger speed, and three states describing the actuator dynamics. The model is more complex than e.g. the third order model in [12] that only describes the pressure and turbocharger dynamics, but it is considerably less complex than a GT-POWER model or a Ricardo WAVE model. Many models in the literature, that approximately have the same complexity as the model proposed here, use three states for each control volume in order to describe the temperature dynamics. However, the model proposed here uses only two states for each manifold. Model extensions are investigated showing that inclusion of temperature states and pressure drop over the intercooler only have minor effects on the dynamic behavior and does not improve the model quality. Therefore, these extensions are not included in the proposed model. Model equations and tuning methods are described for each subsystem in the model. In order to have a low number of tuning parameters, flows and efficiencies are modeled using physical relationships and parametric models instead of look-up tables. To tune and validate the model, stationary and dynamic measurements have been performed in an engine laboratory at Scania CV AB. Static and dynamic validations of the entire model using dynamic experimental data show that the mean relative errors are 12.7 % or lower for all measured variables. The validations also show that the proposed model captures the essential system properties, i.e. a non-minimum phase behavior in the channel EGR-valve to intake manifold pressure and a non-minimum phase behavior, an overshoot, and a sign reversal in the channel VGT to compressor mass flow.

  • 132.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Modeling of a Diesel Engine with VGT and EGR including Oxygen Mass Fraction2006Report (Other academic)
    Abstract [en]

    A mean value model of a diesel engine with VGT and EGR and that includes oxygen mass fraction is developed and validated. The intended model applications are system analysis, simulation, and development of model-based control systems. Model equations and tuning methods are described for each subsystem in the model. In order to decrease the amount of tuning parameters, flows and efficiencies are modeled using physical relationships and parametric models instead of look-up tables. The static models have mean relative errors that are equal to or lower than 6.1%. Static and dynamic validations of the entire model show that the mean relative errors are less than 12%. The validations also show that the proposed model captures the essential system properties, i.e. a non-minimum phase behavior in the transfer function EGR-valve to intake manifold pressure and a non-minimum phase behavior, an overshoot, and a sign reversal in the transfer function VGT to compressor mass flow.

  • 133.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Modelling diesel engines with a variable-geometry turbocharger and exhaust gas recirculation by optimization of model parameters for capturing non-linear system dynamics2011In: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering, ISSN 0954-4070, E-ISSN 2041-2991, Vol. 225, no 7, p. 960-986Article in journal (Refereed)
    Abstract [en]

    A mean-value model of a diesel engine with a variable-geometry turbocharger (VGT) and exhaust gas recirculation (EGR) is developed, parameterized, and validated. The intended model applications are system analysis, simulation, and development of model-based control systems. The goal is to construct a model that describes the gas flow dynamics including the dynamics in the manifold pressures, turbocharger, EGR, and actuators with few states in order to obtain short simulation times. An investigation of model complexity and descriptive capabilities is performed, resulting in a model that has only eight states. A Simulink implementation including a complete set of parameters of the model are available for download. To tune and validate the model, stationary and dynamic measurements have been performed in an engine laboratory. All the model parameters are estimated automatically using weighted least-squares optimization and it is shown that it is important to tune both the submodels and the complete model and not only the submodels or not only the complete model. In static and dynamic validations of the entire model, it is shown that the mean relative errors are 5.8 per cent or lower for all measured variables. The validations also show that the proposed model captures the system properties that are important for control design, i.e. a non-minimum phase behaviour in the channel EGR valve to the intake manifold pressure and a non-minimum phase behaviour, an overshoot, and a sign reversal in the VGT to the compressor mass flow channel, as well as couplings between channels.

  • 134.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Non-linear Compensator for handling non-linear Effects in EGR VGT Diesel Engines2009Report (Other academic)
    Abstract [en]

    A non-linear compensator is investigated for handling of non-linear effects in diesel engines. This non-linear compensator is a non-linear state dependent input transformation that is developed by inverting the models for EGR-flow and turbine flow having actuator position as input and flow as output. The non-linear compensator is used in an inner loop in a control structure for coordinated control of EGR-fraction and oxygen/fuel ratio. A stability analysis of the open-loop system with a non-linear compensator shows that it is unstable in a large operating region. This system is stabilized by a control structure that consists of PID controllers and min/max-selectors. The EGR flow and the exhaust manifold pressure are chosen as feedback variables in this structure. Further, the set-points for EGR-fraction and oxygen/fuel ratio are transformed to set-points for the feedback variables. In order to handle model errors in this set-point transformation, an integral action on oxygen/fuel ratio is used in an outer loop. Experimental validations of the proposed control structure show that it handles nonlinear effects, and that it reduces EGR-errors but increases the pumping losses compared to a control structure without non-linear compensator.

  • 135.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Nonlinear EGR and VGT Control with Integral Action for Diesel Engines2011In: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 66, no 4, p. 573-586Article in journal (Refereed)
    Abstract [en]

    Nonlinear EGR and VGT Control with Integral Action for Diesel Engines - A nonlinear multivariable control design with integral action is proposed and investigated for control of Exhaust Gas Recirculation (EGR) and Variable Geometry Turbine (VGT) in heavy duty Diesel engines. The main control goal is to regulate oxygen/fuel ratio and intake manifold EGR-fraction, and they are specified in an outer loop. These are chosen as main performance variables since they are strongly coupled to the emissions. An existing nonlinear control design based on feedback linearization is extended with integral action. In particular; the control design method utilizes a control Lyapunov function, inverse optimal control, and a nonlinear input transformation. Comparisons between different control structures are performed in simulations showing the following four points. Firstly, integral action is necessary to handle model errors so that the controller can track the performance variables specified in the outer loop. Secondly the proposed control design handles the nonlinear effects in the Diesel engine that results in less control errors compared to a control structure with PID controllers. Thirdly, it is important to use the input transformation and it is sufficient to use a control structure with PID controllers and input transformation to handle the nonlinear effects. Fourthly, the proposed control design is sensitive to model errors in the input transformation while a control structure with PID controllers and input transformation handles these model errors.

  • 136.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Nonlinear EGR and VGT Control with Integral Action for Diesel Engines2009In: 2009 IFAC Workshop on Engine and Powertrain Control, Simulation and Modeling. Paris, France., Curran Associates, Inc., 2009Conference paper (Refereed)
    Abstract [en]

    A non-linear multivariable control design with integral action is proposed and investigated for control of Exhaust Gas Recirculation (EGR) and Variable Geometry Turbocharger (VGT) in heavy duty diesel engines. The main control goal is to regulate oxygen/fuel ratio and intake manifold EGR-fraction, and they are specified in an outer loop. These are chosen as main performance variables since they are strongly coupled to the emissions. An existing non-linear control design based on feedback linearization is extended with integral action. In particular the control design method utilizes a control Lyapunov function, inverse optimal control, and a non-linear compensator. Comparisons between different control structures are performed in simulations showing the following four points. Firstly, integral action is necessary to handle model errors so that the controller can track the performance variables specified in the outer loop. Secondly, the proposed control design handles the non-linear effects in the diesel engine that results in less control errors compared to a control structure with PID controllers. Thirdly, it is important to use the non-linear compensator and it is sufficient to use a control structure with PID controllers and a non-linear compensator to handle the non-linear effects. Fourthly, the proposed control design is sensitive to model errors in the EGR and turbine flow model while a control structure with PID controllers and a non-linear compensator handles these model errors.

  • 137.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Output Selection and Its Implications for MPC of EGR and VGT in Diesel Engines2013In: IEEE Transactions on Control Systems Technology, ISSN 1063-6536, E-ISSN 1558-0865, Vol. 21, no 3, p. 932-940Article in journal (Refereed)
    Abstract [en]

    Control of exhaust gas recirculation (EGR) and variable geometry turbine in diesel engines is a challenging problem and model predictive control (MPC) seems to be a promising method. In MPC the choice of output variables, and thereby the criterion, has a direct impact on the optimization problem to solve and the resulting control performance. Different selections of outputs are investigated and discussed, proposing that it is beneficial to include EGR-fraction and pumping losses in the criterion while having the oxygen/fuel ratio as a constraint. The rational for this constraint is that, in diesel engines, it is allowed to have the oxygen/fuel ratio larger than a set-point. The proposed design also includes integral action of the EGR-fraction to handle model errors and prediction of engine load and speed. A comparison is made between the proposed MPC, a proportional-integral-derivative (PID) controller, and an MPC with intake manifold pressure and compressor flow as outputs, which is the common choice in the literature. Comparisons are performed in simulation on the European transient cycle showing the following two points. First, the proposed design gives 9% lower oxygen/fuel ratio error, 80% lower EGR-error, and 12% lower pumping losses compared to an MPC design with intake manifold pressure and compressor flow as outputs. Second, the proposed design gives 9% lower EGR-error and 6% lower pumping losses compared to a control structure with PID controllers with oxygen/fuel ratio and EGR-fraction as the main outputs.

  • 138.
    Wahlström, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Eriksson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Performance gains with EGR-flow inversion for handling non-linear dynamic effects in EGR VGT CI engines2007In: Fifth IFAC Symposium on Advances in Automotive Control,2007, 2007, p. 531-538Conference paper (Refereed)
    Abstract [en]

    A non-linear compensator, that handles non-linear dynamic effects in diesel engines, is investigated. The non-linear compensator is an inversion of the EGR-flow model that is used in an inner loop in a control structure for coordinated control of EGR-fraction and oxygen/fuel ratio. A mapping of the sign reversal and the non-minimum phase behavior in VGT-position to oxygen/fuel ratio when the non-linear compensator is used shows that these system properties occur only when the EGR-valve is saturated. Simulations of a closed loop system shows that a control structure with the non-linear compensator gives less overshoots in oxygen/fuel ratio and less pumping work compared to a control structure without a non-linear compensator. The simulations show also that the mean absolute EGR error can be reduced with 95 % if an ideal EGR-actuator is used.

  • 139.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Robust Nonlinear EGR and VGT Control with Integral Action for Diesel Engines2008In: Proceedings of the 17th IFAC World Congress, Seoul, Korea: The International Federation of Automatic Control , 2008, p. 2057-2062Conference paper (Refereed)
    Abstract [en]

    A robust non-linear multivariable control design with integral action is proposed and investigated for control of EGR valve and VGT position in heavy duty diesel engines. The main control goal is to regulate oxygen/fuel ratio and intake manifold EGR-fraction. These are chosen as main performance variables since they are strongly coupled to the emissions. A recently developed non-linear control design based on feedback linearization is extended with integral action. The nonlinear controller gives an inner loop with good stability and robustness properties. It is shown that integral action is necessary to handle model errors so that the controller can track the performance variables specified in the outer loop. In particular the control design method utilizes a control Lyapunov function and inverse optimal control, which results in a control law with robustness properties interpretable as gain and phase margins. Furthermore, comparisons by simulation also show that the proposed control design successfully handles non-linear effects.

  • 140.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Nielsen, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Controller Tuning based on Transient Selection and Optimization for a Diesel Engine with EGR and VGT2008In: Electronic Engine Controls, SAE World Congress & Exhibition, April, Detroit, MI, USA: SAE Technical paper series SP-2159, 2008-01-0985, SAE International , 2008, p. 2008-01-0985-Conference paper (Refereed)
    Abstract [en]

    In modern Diesel engines Exhaust Gas Recirculation (EGR) and Variable Geometry Turbochargers (VGT) have been introduced to meet the new emission requirements. A control structure that coordinates and handles emission limits and low fuel consumption has been developed. This controller has a set of PID controllers with parameters that need to be tuned. To be able to achieve good performance, an optimization based tuning method is developed and tested. In the optimization the control objectives are captured by a cost function. To aid the tuning a systematic method has been developed for selecting representative and significant transients that excite different modes in the controller. The performance is evaluated on the European Transient Cycle. It is demonstrated how weighting factors in the cost function influence control behavior, and that the proposed tuning method gives a significant improvement in control performance compared to standardized tuning methods for PID controllers. Further, the proposed tuning method and the control structure are applied and validated on an engine in a test cell, where it is demonstrated that the control structure achieves all stated control objectives.

  • 141.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Nielsen, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    EGR-VGT Control and Tuning for Pumping Work Minimization and Emission Control2010In: IEEE Transactions on Control Systems Technology, ISSN 1063-6536, E-ISSN 1558-0865, Vol. 18, no 4, p. 993-1003Article in journal (Refereed)
    Abstract [en]

    A control structure is proposed and investigated for coordinatedcontrol of EGR valve and VGT position in heavy duty diesel engines.Main control goals are to fulfill the legislated emission levels, toreduce the fuel consumption, and to fulfill safe operation of theturbocharger. These goals are achieved through regulation ofnormalized oxygen/fuel ratio and intake manifoldEGR-fraction. These are chosen both as main performance variables andfeedback variables since they contain information about when it ispossible to decrease the fuel consumption by minimizing the pumpingwork. Based on this a novel and simple pumping work minimizationstrategy is developed.The proposed performance variables are also strongly coupled to theemissions which makes it easier to adjust set-points, e.g. dependingon measured emissions during an emission calibration process, since itis more straightforward than control of manifold pressure and air massflow. Further, internally the controller is structured to handle thedifferent control objectives. Controller tuning is important forperformance but can be time consuming and to meet this end a method isdeveloped where the controller objectives are captured in a costfunction, which makes automatic tuning possible even though objectivesare conflicting. Performance trade-offs are necessary and areillustrated on the European Transient Cycle. The proposed controlleris validated in an engine test cell, where it is experimentallydemonstrated that the controller achieves all the control objectivesand that the current production controller has at least 26% higherpumping losses compared to the proposed controller.

  • 142.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Nielsen, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    System analysis of a Diesel Engine with VGT and EGR2009Report (Other academic)
    Abstract [en]

    A system analysis of a diesel engine with VGT and EGR is performed in order to obtain insight into a VGT and EGR control problem where the goal is to control the performance variables oxygen fuel ratio and EGR-fraction using the VGT actuator and the EGR actuator. Step responses over the entire operating region show that the channels VGT to oxygen fuel ratio, EGR-valve to oxygen fuel ratio, and VGT to EGR-fraction have non-minimum phase behaviors and sign reversals. The fundamental physical explanation of these system properties is that the system consists of two dynamic effects that interact: a fast pressure dynamics in the manifolds and a slow turbocharger dynamics. It is shown that the engine frequently operates in operating points where the non-minimum phase behaviors and sign reversals occur for the channels VGT to oxygen fuel ratio and VGT to EGR-fraction, and consequently, it is important to consider these properties in a control design. Further, an analysis of zeros for linearized multiple input multiple output models of the engine shows that they are non-minimum phase over the complete operating region. A mapping of the performance variables oxygen fuel ratio and EGR-fraction and the relative gain array show that the system from EGR-valve and VGT to oxygen fuel ratio and EGR-fraction is strongly coupled in a large operating region. It is also illustrated that the pumping losses decrease with increasing EGR-valve and VGT opening for almost the complete operating region.

  • 143.
    Wahlström, Johan
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Nielsen, Lars
    Linköping University, Department of Electrical Engineering. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Pettersson, Magnus
    Engine Software and OBD Scania.
    PID controllers and their tuning for EGR and VGT control in diesel engines2005In: Preprints of the 16th IFAC World Congress, Prague, Czech Republic: Elsevier , 2005Conference paper (Refereed)
    Abstract [en]

    A PID structure is proposed and investigated for coordinated control of EGR-valve and VGT-position in heavy duty diesel engines. Control goals are to fulfill the legislated emission levels and safe operations of the engine and the turbocharger. These goals are achieved through regulation of the following performance variables: normalized air/fuel ratio lambda, intake manifold EGR-fraction as well as turbocharger speed. A systematic tuning strategy for the PID controllers is also developed and the tuning rules and their performance is successfully illustrated on a demanding part of the European Transient Cycle. Further, it is demonstrated that the VGT-position to turbocharger speed loop does benefit from a derivative part in order to predict high turbocharger speeds. This is due to the large time constant in the corresponding open-loop transfer function.

  • 144.
    Xie, Hui
    et al.
    Tianjin University, Tianjin Shi, China.
    Stobart, Richard
    Loughborough University, Loughborough, UK.
    Tunestål, Per
    Lund University, Lund Sweden.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Huang, Yiqun
    Houston Advanced Research Center, USA.
    Leteinturier, Patrick
    Infineon Technologies.
    Future Engine Control Enabling Environment Friendly Vehicle2011In: Proceedings of SAE 2011 World Congress & Exhibition, Society of Automotive Engineers, 2011, article id 2011-01-0697Conference paper (Refereed)
    Abstract [en]

    The aim of this paper is to compile the state of the art of engine control and develop scenarios for improvements in a number of applications of engine control where the pace of technology change is at its most marked. The first application is control of downsized engines with enhancement of combustion using direct injection, variable valve actuation and turbo charging. The second application is electrification of the powertrain with its impact on engine control. Various architectures are explored such as micro, mild, full hybrid and range extenders. The third application is exhaust gas after-treatment, with a focus on the trade-off between engine and after-treatment control. The fourth application is implementation of powertrain control systems, hardware, software, methods, and tools.

    The paper summarizes several examples where the performance depends on the availability of control systems for automotive applications. In addition it presents several open research topics with a commentary on current research direction and objectives.

  • 145.
    Öberg, Per
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Control Oriented Gas Exchange Models for CVCP Engines and their Transient Sensitivity2007In: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 62, no 4, p. 573-584 Article in journal (Refereed)
    Abstract [en]

    The paper analyzes a set of control oriented models for the gas exchange phase in engines with continuously variable cam phasing (CVCP). These models describe the mass flow of fresh gases and the residual gases caught in the cylinder during the gas exchange phase. Simulations with CVCP transients are also performed to analyze the models performance during transients.

  • 146.
    Öberg, Per
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Eriksson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Control Oriented Gas Exchange Models for CVCP Engines and their Transient Sensitivity2006In: New Trends in Engine Control, Simulation and Modelling,2006, 2006, p. 181-192Conference paper (Refereed)
  • 147.
    Öberg, Per
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Control Oriented Modeling of the Gas Exchange Process in Variable Cam Timing Engines2006In: SAE Technical Paper 2006-01-0660, SAE , 2006Conference paper (Refereed)
    Abstract [en]

    Variable cam timing engines pose new questions for engine control system designers. The cam timing directly influences cylinder air charge and residual mass fraction. Three models that predict residual mass fraction are investigated for a turbocharged dual independent Variable Cam Timing (VCT) engine. The three models (Fox et. al. 1993, Ponti et. al. 2002, and Mladek et. al. 2000) that all have real time capabilities are evaluated and validated against data from a crank angle based reference model. None of these models have previously been validated to cover this engine type. It is shown that all three models can be extended to dual independent VCT engines and that they also give a good description of the residual gas fraction. However, it is shown that the two most advanced models, based on a thermodynamic energy balance, are very sensitive to the model inputs and proper care must therefore be taken when these models are used

  • 148.
    Öberg, Per
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Modeling of the Gas Exchange Process in Variable Cam Timing Engines2004In: Proceedings of the 5th Conference on Computer Science and Systems Engineering (CCSSE'04), Linköping, Sweden: Linköpings University , 2004Conference paper (Other academic)
    Abstract [en]

    n/a

123 101 - 148 of 148
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