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  • 1.
    Alegret, Guillem
    et al.
    MAN Diesel & Turbo, Copenhagen, Denmark.
    Llamas, Xavier
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Vejlgaard-Laursen, Morten
    MAN Diesel & Turbo, Copenhagen, Denmark.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Modeling of a Large Marine Two-Stroke Diesel Engine with Cylinder Bypass Valve and EGR System2015In: 10th IFAC Conference on Manoeuvring and Control of Marine Craft MCMC 2015: Copenhagen, 24–26 August 2015 / [ed] Roberto Galeazzi and Mogens Blanke, IFAC Papers Online, 2015, Vol. 48, p. 273-278Conference paper (Refereed)
    Abstract [en]

    A nonlinear mean value engine model (MVEM) of a two-stroke turbocharged marine diesel engine is developed, parameterized and validated against measurement data. The goal is to have a computationally fast and accurate engine model that captures the main dynamics and can be used in the development of control systems for the newly introduced EGR system. The tuning procedure used is explained, and the result is a six-state MVEM with seven control inputs that capture the main system dynamics.

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  • 2.
    Andersson, Ingemar
    et al.
    Chalmers.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering.
    A Parametric Model for Ionization Current in a Four Stroke SI Engine2009In: JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME, ISSN 0022-0434, Vol. 131, no 2, p. 021001-Article in journal (Refereed)
    Abstract [en]

    A model for the thermal part of an ionization signal is presented that connects the ionization current to cylinder pressure and temperature in a spark ignited internal combustion engine. One strength of the model is that, after calibration, it has only two free parameters: burn angle and initial kernel temperature. By fitting the model to a measured ionization signal, it is possible to estimate both cylinder pressure and temperature, where the pressure is estimated with good accuracy. The model approach is validated on engine data. Cylinder pressure and ionization current data were collected on a Saab four-cylinder spark ignited engine for a variation in ignition timing and air-fuel ratio. The main result is that the parametrized ionization current model can be used to estimating combustion properties as pressure, temperature, and content of nitric oxides based on measured ionization currents. The current status of the model is suitable for off-line analysis of ionization currents and cylinder pressure. This ionization current model not only describes the connection between the ionization current and the combustion process, but also offers new possibilities for engine management system to control the internal combustion engine.

  • 3.
    Andersson, Ingemar
    et al.
    Chalmers.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Ion Current Interpretation for Sensing and Control of Combustion Stability1999In: Second conference on Computer Science and Systems Engineering in Linköping, 1999, p. 119-124Conference paper (Refereed)
  • 4.
    Andersson, Ingemar
    et al.
    Chalmers.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Ion Sensing for Combustion Stability Control of a Spark Ignited Direct Injected Engine2000In: Electronic Engine Controls: Controls, 2000, Vol. SP-1500Conference paper (Refereed)
    Abstract [en]

    The combustion stability of a direct injected spark ignited engine depends on the injection timing and it is desirable to have a controller that minimizes the combustion variability. A novel approach for determining combustion stability in stratified mode is presented that rely on the ionization current and enables closed loop control of the injection timing. The coefficient of variation for IMEP is used as a measure of combustion stability and a connection between maximum torque and low combustion variability is pointed out. The coefficient of variation of the ion current integral is well correlated with the coefficient of variation for IMEP. Furthermore, it is shown how the integral of the ion current together with COV(ion integral) can be used to determine the combustion stability and to distinguish high combustion stability from misfire.

  • 5.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering.
    Air-to-Cylinder Observer on a Turbocharged SI-Engine with Wastegate2001Conference paper (Refereed)
    Abstract [en]

    Observers for air mass flow to the cylinder is studied on a turbocharged SI-engine with wastegate. A position change of the wastegate influences the residual gas mass and causes the volumetric efficiency to change, which produces a transient in the air mass flow to the cylinder. Two standard methods of estimating air-to-cylinder are investigated. A new nonlinear air-to-cylinder observer is suggested with two states: one for intake manifold pressure and one for the offset in in-cylinder air mass compared to expected through the volumetric efficiency. The observers are validated on intake manifold pressure data from a turbocharged spark ignited production engine with wastegate.

  • 6.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering.
    Cylinder Air Charge Estimator in Turbocharged SI-Engines2004Conference paper (Refereed)
  • 7.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering.
    Detection of Exhaust Manifold Leaks on a Turbocharged SI-engine with Wastegate2002Conference paper (Refereed)
  • 8.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering.
    Exhaust Manifold Pressure Estimation on a Turbocharged SI-engine with Wastegate2001Conference paper (Refereed)
  • 9.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering.
    Mean-value Observer for a Turbocharged SI-engine2004Conference paper (Refereed)
  • 10.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Observer Based Feedforward Air-Fuel Control of Turbocharged SI-Engines2005Conference paper (Refereed)
    Abstract [en]

    Abstract: Air-fuel control on turbocharged (TC) SI-engines require precise prediction of the cylinder air-charge (CAC). Using an observer it is possible to both estimate the necessary system states and to provide a framework to design the necessary CAC feedforward controller. Here a mean value engine model of a TC SI-engine is used to develop an observer. The output of the observer is fed as an initial condition to a predictor which is used for feedforward of the CAC for air-fuel control. The resulting controller is experimentally validated on a SAAB 2.0 dm^3 TC engine using tip-in and tip-out transients. The results show that the excursions in lambda are less than 5%.

  • 11.
    Andersson, 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.
    Observer Based Feedforward Air-Fuel Control of Turbocharged SI-Engines2005In: Proceedings of 16th Triennial World Congress, Prague, Czech Republic, IFAC Papers Online, 2005, Vol. 38, p. 200-205Conference paper (Refereed)
    Abstract [en]

    Air-fuel control on turbocharged (TC) SI-engines require precise prediction of the cylinder air-charge (CAC). Using an observer it is possible to both estimate the necessary system states and to provide a framework to design the necessary CAC feedforward controller. Here a mean value engine model of a TC SI-engine is used to develop an observer. The output of the observer is fed as an initial condition to a predictor which is used for feedforward of the CAC for air-fuel control. The resulting controller is experimentally validated on a SAAB 2.0 dm3 TC engine using tip-in and tip-out transients. The results show that the excursions in Λ are less than 5%

  • 12.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Three Way Catalyst Control using a PI-style Controller with HEGO Sensor Feedback2002Conference paper (Refereed)
    Abstract [en]

    Recent research has shown that control of the oxygen content in the catalyst has potential to further reduce the emissions from spark ignited engines. This gives rise to a cascade structure where an outer loop influences an inner loop. Different ways of augmenting the inner loop, a traditional PI-feedback controller based on feedback from the binary oxygen sensor, are studied. The SI-engine constraints on the control, such as low emissions and drive ability, are considered in the evaluation of the controllers. The result is that a delayed switching of the sensor is needed to control the oxygen content in the TWC using binary sensor feedback.

  • 13.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering.
    Three Way Catalyst Control using PI-style Controller with HEGO Sensor Feedback2002Conference paper (Refereed)
  • 14.
    Andersson, Per
    et al.
    Linköping University, Department of Electrical Engineering.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering.
    Nielsen, Lars
    Linköping University, Department of Electrical Engineering.
    Modeling and Architecture Examples of Model Based Engine Control1999Conference paper (Refereed)
  • 15. Andersson, Per
    et al.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Nielsen, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Modelling and Architecture Examples of Model Based Engine Control1999Conference paper (Refereed)
    Abstract [en]

    Environmental regulations and drivability issues are driving forces in the development of control systems for automotive engines. Precise control of the air and fuel is fundamental for achieving the goals. Furthermore, the architecture for the controller plays a central role in how the goals are achieved.

    A comparison is made between two conventional controller structures and a model based structure. The performance of the different control structures is evaluated on a simulation model. To point out the differences the evaluation is concentrated to transient conditions where a step in throttle angle is used as input to the system. In addition, connections between controllers and the engine model is discussed.

  • 16.
    Andersson, Per
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Frisk, Erik
    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.
    Sensor Selection for Observer Feedback in Turbocharged Spark Ignited Engines2005Conference paper (Refereed)
  • 17.
    Bachmann, Bernhard
    et al.
    Dept. Mathematics and Engineering, University of Applied Sciences, Bielefeld, Germany.
    Ochel, Lennart
    Dept. Mathematics and Engineering, University of Applied Sciences, Bielefeld, Germany.
    Ruge, Vitalij
    Dept. Mathematics and Engineering, University of Applied Sciences, Bielefeld, Germany.
    Gebremedhin, Mahder
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory.
    Fritzson, Peter
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory.
    Nezhadali, Vaheed
    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.
    Sivertsson, Martin
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Parallel Multiple-Shooting and Collocation Optimization with OpenModelica2012In: Proceedings of the 9th International MODELICA Conference; September 3-5; 2012; Munich; Germany, Linköping University Electronic Press, 2012, p. 659-668, article id 067Conference paper (Refereed)
    Abstract [en]

    Nonlinear model predictive control (NMPC) has become increasingly important for today’s control engineers during the last decade. In order to apply NMPC a nonlinear optimal control problem (NOCP) must be solved which needs a high computational effort.

    State-of-the-art solution algorithms are based on multiple shooting or collocation algorithms; which are required to solve the underlying dynamic model formulation. This paper describes a general discretization scheme applied to the dynamic model description which can be further concretized to reproduce the mul-tiple shooting or collocation approach. Furthermore; this approach can be refined to represent a total collocation method in order to solve the underlying NOCP much more efficiently. Further speedup of optimization has been achieved by parallelizing the calculation of model specific parts (e.g. constraints; Jacobians; etc.) and is presented in the coming sections.

    The corresponding discretized optimization problem has been solved by the interior optimizer Ipopt. The proposed parallelized algorithms have been tested on different applications. As industrial relevant application an optimal control of a Diesel-Electric power train has been investigated. The modeling and problem description has been done in Optimica and Modelica. The simulation has been performed using OpenModelica. Speedup curves for parallel execution are presented.

  • 18.
    Balachandran, Arvind
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Jonsson, Tomas
    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.
    Design and Analysis of Battery-Integrated Modular Multilevel Converters for Automotive Powertrain Applications2021In: 2021 23RD EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE21 ECCE EUROPE), IEEE , 2021Conference paper (Refereed)
    Abstract [en]

    The automotive industry has grown considerably over the last century consequently increasing green-house gas emissions and thus contributing towards increase in the average global temperature. It is thus of paramount importance to increase the use of alternative energy sources. Electric vehicles have gained popularity over the last decade. However, a major concern with electric vehicles is their range. The range of an electric vehicle is limited by the battery pack, in particular, the weakest cell of the pack. One method of increasing the available energy from the battery pack is by introducing more electronics. Modular multilevel converters, with their modular concept, could be a viable solution. The concept of battery-integrated modular multilevel converters (BI-MMC) for automotive applications is explored. In particular, the impact of the number of cascaded cells per submodule is investigated, considering battery losses, DC-link capacitor losses, and the converter losses. Furthermore, an optimization of the DC-link capacitors and the selection of MOSFET switching frequency is presented in order to minimize the total losses.

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  • 19.
    Balachandran, Arvind
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Jonsson, Tomas
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering. Scania, Södertalje, Sweden.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Larsson, Anders
    Scania, Södertalje, Sweden.
    Experimental Evaluation of Battery Impedance and Submodule Loss Distribution for Battery Integrated Modular Multilevel Converters2022In: 2022 24TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE22 ECCE EUROPE), Institute of Electrical and Electronics Engineers (IEEE), 2022Conference paper (Refereed)
    Abstract [en]

    Greenhouse gas emissions and the increase in average global temperature are growing concerns now more so than ever. Therefore it is of importance to increase the use of alternative energy sources, especially in the automotive industry. Battery electric vehicles (BEV) have gained popularity over the past several years. However, the performance of a BEV is limited by the battery pack, in particular, the weakest cell in the pack. Therefore, improved cell controllability and high efficiency are seen as important directions for research and development and one direction where it can be achieved is through using battery-integrated modular multilevel converters (BI-MMC). The battery current in BI-MMCs contains additional harmonics and the frequency dependent losses of these harmonics are determined by the resonance between the battery and the DC-link capacitor bank. The paper presents an experimental validation of previously published theoretical results for both harmonic allocations and loss distribution at the switching frequency within the BI-MMC submodule. Furthermore, a methodology for measuring the battery impedance using the full-load converter switching currents is presented.

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  • 20.
    Balachandran, Arvind
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Jonsson, Tomas Uno
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering. Scania AB, Södertalje, Sweden.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    DC Charging Capabilities of Battery-Integrated Modular Multilevel Converters Based on Maximum Tractive Power2023In: Electricity, E-ISSN 2673-4826, Vol. 4, no 1, p. 62-77Article in journal (Refereed)
    Abstract [en]

    The increase in the average global temperature is a consequence of high greenhouse gas emissions. Therefore, using alternative energy carriers that can replace fossil fuels, especially for automotive applications, is of high importance. Introducing more electronics into an automotive battery pack provides more precise control and increases the available energy from the pack. Battery-integrated modular multilevel converters (BI-MMCs) have high efficiency, improved controllability, and better fault isolation capability. However, integrating the battery and inverter influences the maximum DC charging power. Therefore, the DC charging capabilities of 5 3-phase BI-MMCs for a 40-ton commercial vehicle designed for a maximum tractive power of 400 kW was investigated. Two continuous DC charging scenarios are considered for two cases: the first considers the total number of submodules during traction, and the second increases the total number of submodules to ensure a maximum DC charging voltage of 1250 V. The investigation shows that both DC charging scenarios have similar maximum power between 1 and 3 MW. Altering the number of submodules increases the maximum DC charging power at the cost of increased losses.

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  • 21.
    Broomhead, Timothy James
    et al.
    Department of Mechanical Engineering, The University of Melbourne, Australia.
    Manzie, Chris
    Department of Mechanical Engineering, The University of Melbourne, Australia.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Brear, Michael
    Department of Mechanical Engineering, The University of Melbourne, Australia.
    Hield, Peter
    Defence Science and Technology Organisation, Australia.
    A Robust Model Predictive Control Framework for Diesel Generators2014In: Proceedings of 19th IFAC World Congress / [ed] Edward Boje; Xiaohua Xia, International Federation of Automatic Control (IFAC) , 2014, Vol. 47, p. 11848-11853Conference paper (Refereed)
    Abstract [en]

    A constraint tightened linear-time-varying MPC framework is proposed with applications in power tracking for variable and fixed speed generators. Current constraint tightening approaches are extended to allow for practical applications where future system representations are unknown. The resulting control structure is shown to be robustly feasible under given conditions. Knowledge about the geometry of system constraints is exploited to obtain a computationally efficient method of computing tightened sets online. A simulation study is presented demonstrating the ability of the controller to handle modelling error and demonstrate tracking of a commanded power profile.

  • 22.
    Brugård, Jan
    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.
    Mean Value Engine Modeling of a Turbo Charged Spark Ignited Engine: A Principle Study2001Report (Other academic)
    Abstract [en]

    Object oriented modeling of physical systems is an interesting paradigm, which has the potential to offer reusable models and model components. The aim of this study i to investigate how to build mean value models for automotive engines. MathModelica, a modeling tool for the object oriented modeling language Modelica, is used in this study. Several sub models have been developed for the different parts of the engine. Th models cover the air filter, intercooler, throttle, base engien, exhaust system, compressor, turbine, turbine shaft, and volumes. It is shown how the components can be connected to form both turbo charged engines as well as a naturally aspirated engines, which shows that the paradigm is applicable for the modeling and confirms the modeling principle. One problem that has popped up att several occasions is the selection of initial conditions for the simulation. Especially when restrictions with low pressure drops are connected between two volumes, the simulation engine has problems finding initial conditions. The models have been compared to measured engine data collected at a test bench in Vehicular Systems laboratory at Linköping University. The agreement with measurement data is good and the models work as expected.

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    Mean Value Engine Modeling of a Turbo Charged Spark Ignited Engine - A Principle Study
  • 23.
    Criscuolo, Ivan
    et al.
    Department of Mechanical Engineering, University of Salerno, Fisciano, Italy.
    Leufvén, Oskar
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Thomasson, Andreas
    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 Boost Pressure Control with System Voltage Disturbance Rejection2011In: Proceedings of the 18th IFAC World Congress, 2011 / [ed] Bittanti, Sergio, Cenedese, Angelo, Zampieri, Sandro, International Federation of Automatic Control (IFAC) , 2011, p. 5058-5063Conference paper (Refereed)
    Abstract [en]

    Actuation systems for automotive boost control incorporate a vacuum tank and PWM controlled vacuum valves to increase the boosting system flexibility. Physical models for the actuator system are constructed using measurement data from a dynamometer with an engine having a two stage turbo system. The actuator model is integrated in a complete Mean Value Engine Model and a boost pressure controller is constructed. The developed model is used as basis for a nonlinear compensator, that is capable of rejecting disturbances from system voltage. An IMC based boost pressure controller is developed for the vacuum actuator and engine by using the engine model and then tested on the test cell. The controller performance is quantified and system voltage disturbance rejection is demonstrated.

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  • 24.
    Edlund, Simon
    et al.
    Nokia Svenska AB, Linköping, SWEDEN.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Nielsen, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Pettersson, Magnus
    SCANIA AB, Södertälje. SWEDEN.
    A Real-Time Platform for Collaboration Projects in Power Train Modeling and Control1999Conference paper (Refereed)
    Abstract [en]

    The requirements on research and development in automotive control are growing fast, and therefore convenient and efficient ways to make prototype experiments and demonstrations are sought for. Collaboration projects put some additional constraints on the experimental system used due to issues of safety and secrecy. These requirements are outlined, a real-time platform is developed, and experiences from some collaboration projects between industry and academia are discussed.

  • 25.
    Ekberg, Kristoffer
    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.
    A Comparison of Optimal Gear Shifts for Stiff and Flexible Driveshafts During Accelerations2020Conference paper (Refereed)
    Abstract [en]

    Reducing the fuel consumption is important and much development work is on engine optimization for best stationary fuel consumption. Here, a solution is developed for the transient operation to get fuel optimal accelerations, considering the actuation of fuel injection, wastegate control and gear utilization. The transient acceleration scenario studied is; a truck is approaching a red light at slow rolling speed, the light turns green and the truck shall be accelerated to 50 km/h with minimum fuel. Optimal control is used to find the fuel optimal control strategies. By using a dynamic engine model, taking the turbocharger dynamics into consideration, the engine air fuel ratio is taken into account. The differences and similarities between a stiff and flexible driveline model, are analyzed. The results show that the most dominating effect is the turbocharger dynamics of the engine. The two drivelines have similar gear changing strategies while the finer details differ due to the additional degrees of freedom that are present in the flexible driveline.

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  • 26.
    Ekberg, Kristoffer
    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.
    Development and Analysis of Optimal Control Strategy for Gear Changing Patterns During Acceleration2019In: IFAC PAPERSONLINE, ELSEVIER , 2019, Vol. 52, no 5, p. 316-321Conference paper (Refereed)
    Abstract [en]

    Vehicle speed planning for heavy duty vehicles is a powerful tool to reduce the fuel consumption, and thereby the emissions released from the vehicle. By optimizing a driving mission for lowest possible fuel consumption, while still fulfilling the mission deadlines, the fuel consumption could be reduced over that specific mission. If the vehicle is driven by a combustion engine, the engine efficiency will be dependent on the load and speed requirements from the vehicle. By having a gearbox between the engine and the wheels, the engine operating points could be selected by choosing the appropriate gear. When optimizing gear changes, different model complexities can be used. To solve a gear change problem during acceleration, some key aspects needs to be taken into account, for example the loss of propulsion power when disengaging the clutch, how much clutch slip should be allowed, the time it takes for the gearbox to change the gear. The paper presents a method how to formulate and solve a fuel optimal acceleration of a vehicle, where the gear selections are in focus. The method is used to find which gears that should be used to perform a fuel optimal acceleration to a predefined vehicle speed. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

  • 27.
    Ekberg, Kristoffer
    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.
    Improving Fuel Economy and Acceleration by Electric Turbocharger Control for Heavy Duty Long Haulage2017In: IFAC PAPERSONLINE, ELSEVIER SCIENCE BV , 2017, Vol. 50, no 1, p. 11052-11057Conference paper (Refereed)
    Abstract [en]

    Todays vehicle industry is converging more and more to electrification of vehicles, introducing electrical architectures to cooperate side by side with the combustion engine. This paper investigates the potential of using an electric turbocharger in a long haulage application during highway driving. A charge sustainable control strategy is developed, implemented, tuned, and evaluated on a heavy duty truck model. The benefits of using an electrical turbocharger on a heavy duty diesel truck, from a long haulage perspective, are evaluated. By calibrating the implemented controller, long haulage driving routes can be charge sustainable and consume less fuel than a conventional truck with fix turbine geometry, the fuel savings for the simulated case is 0.9%. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

  • 28.
    Ekberg, Kristoffer
    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.
    The Effect of Pressure Losses on Measured Compressor Efficiency2016In: Proceedings Of The 9Th Eurosim Congress On Modelling And Simulation, Eurosim 2016, The 57Th Sims Conference On Simulation And Modelling Sims 2016, Linköping University Electronic Press, 2016, Vol. 142, p. 251-257, article id 36Conference paper (Refereed)
    Abstract [en]

    While measuring the compressor behavior at different load points in for example a gas stand, the inlet and outlet pressures are not always measured directly before and after the compressor. The friction inside the pipes and the physical piping configuration affect the measured compressor efficiency, due to the induced change of fluid enthalpy. If the measured pressures at the end of the inlet and outlet pipes are not the same as the actual pressure before and after the compressor, the acquired compressor map does not give the right description of it as an isolated component. The main contribution of this paper is the analysis of the impact of gas stand energy losses due to pipe friction on the compressor map. As a result the paper suggests a way to take the pressure losses in the inlet and outlet pipes into account. The suggested model takes pipe friction, diffuser, nozzle and pipe bends into account. The potential measurement error in compressor efficiency due to energy losses in the pipes in this experiment is 2.7% (percentage points) at maximum mass flow of air through the compressor.

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  • 29.
    Ekberg, Kristoffer
    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.
    Sivertsson, Martin
    Linköping University, Department of Electrical Engineering. Linköping University, Faculty of Science & Engineering.
    Cycle Beating - An Analysis of the Boundaries During Vehicle Testing2016In: IFAC PAPERS ONLINE, ELSEVIER SCIENCE BV , 2016, Vol. 49, no 11, p. 657-664Conference paper (Refereed)
    Abstract [en]

    Todays vehicle industry is strictly controlled by environmental legislations. The vehicle industry is spending much money out reducing the fuel consumption and fulfilling the emission requirements to make sales possible in different regions in the world. Before introducing; a vehicle on the market, it is tested according to standardized driving cycles to specify the vehicle pollutant emissions and fuel consumption. These cycles allow some deviation from the reference vehicle speed during tests, e.g. NEDC allows deviations of +/- 2 km/h and +/- 1 s. This paper uses dynamic programming to find fuel optimal velocity profiles, given the allowed deviations of +/- 2 km/h and +/- 1 s from reference speed during drive cycle test. By taking advantage of the allowed deviation, the fuel consumption can be reduced by up to 16.56 % according to model results, ruoriing NEDC if gear selections are unrestricted (i.e. using automatic gearbox), and up to 5.90 % if changing gears according to the specifications in the drive cycle. Two different optimization goals are investigated, minimum amount of mass fuel consumed and best mileage. (C) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

  • 30.
    Ekberg, Kristoffer
    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.
    Sundström, Christofer
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Electrification of a Heavy-Duty CI Truck-Comparison of Electric Turbocharger and Crank Shaft Motor2021In: Energies, E-ISSN 1996-1073, Vol. 14, no 5, article id 1402Article in journal (Refereed)
    Abstract [en]

    A combustion engine-driven vehicle can be made more fuel efficient over some drive cycles by, for example, introducing electric machines and solutions for electrical energy storage within the vehicles driveline architecture. The possible benefits of different hybridization concepts depend on the architecture, i.e., the type of energy storage, and the placement and sizing of the different driveline components. This paper examines a diesel electric plug-in hybrid truck, where the powertrain includes a diesel engine supported with two electric motors, one supporting the crank shaft and one the turbocharger. Numerical optimal control was used to find energy-optimal control strategies during two different accelerations; the trade-off between using electrical energy and diesel fuel was evaluated using a simulation platform. Fixed-gear acceleration was performed to evaluate the contribution from the two electric motors in co-operation, and individual operation. A second acceleration test case from 8 to 80 km/h was performed to evaluate the resulting optimal control behavior when taking gear changes into account. A cost factor was used to relate the cost of diesel fuel to electrical energy. The selection of the cost factor relates to the allowed usage of electrical energy: a high cost factor results in a high amplification from electrical energy input to total system energy savings, whereas a low cost factor results in an increased usage of electrical energy for propulsion. The difference between fixed-gear and full acceleration is mainly the utilization of the electric crank shaft motor. For the mid-range of the cost factors examined, the crank shaft electric motor is used at the end of the fixed-gear acceleration, but the control sequence is not repeated for each gear during the full acceleration. The electric motor supporting the turbocharger is used for higher cost factors than the crank shaft motor, and the amplification from electrical energy input to total energy savings is also the highest.

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  • 31.
    Ekberg, Kristoffer
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Leek, Viktor
    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.
    Modeling and Validation of an Open-Source Mean Value Heavy-Duty Diesel Engine Model2018In: Simulation Notes Europe, ISSN 2306-0271, Vol. 28, no 4, p. 197-204Article in journal (Refereed)
    Abstract [en]

    The pursuit of lower fuel consumption and stricter emission legislation has made a simulation- and optimization-based development methodology important to the automotive industry. The keystone in the methodology, is the system model. But for the results obtained using a model to be credible, the model has to be validated. The paper validates an open-source, meanvalue engine model of a 13 liter CI inline 6 cylinder heavyduty engine, and releases it as open-source.

  • 32.
    Ekberg, Kristoffer
    et al.
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Leek, Viktor
    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.
    Optimal Control of Wastegate Throttle and Fuel Injection for a Heavy-Duty Turbocharged Diesel Engine During Tip-In2017In: Proceedings of the 58th Conference on Simulation and Modelling (SIMS 58) Reykjavik, Iceland, September 25th – 27th, 2017 / [ed] Magnus Thor Jonsson, Linköping University Electronic Press, 2017, Vol. 138, p. 317-325Conference paper (Refereed)
    Abstract [en]

    The diesel engine remains one of the key components in the global economy, transporting most of the worlds goods. To cope with stricter regulations and the continuous demand for lower fuel consumption, optimization is a key method. To enable mathematical optimization of the diesel engine, appropriate models need to be developed. These are preferably continuously differentiable, in order to be used with a gradient-based optimization solver. Demonstration of the optimization-based methodology is also necessary in order for the industry to adapt it. The paper presents a complete mean value engine model structure, tailored for optimization and simulation purposes. The model is validated using measurements on a heavyduty diesel engine. The validated model is used to study the transient performance during a time-optimal tip-in, the results validate that the model is suitable for simulation and optimization studies.

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  • 33.
    Eriksson, Daniel
    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.
    Frisk, Erik
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Krysander, Mattias
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Analysis and optimization with the Kullback-Leibler divergence for misfire detection using estimated torque2013Report (Other academic)
    Abstract [en]

    Engine misfire detection is an important part of the On-Board Diagnostics (OBDII) legislations to reduce exhaust emissions and avoid damage to the catalytic converters. The flywheel angular velocity signal is analyzed, investigating how to use the signal in order to best detect misfires. An algorithm for engine misfire detection is proposed based on the flywheel angular velocity signal. The flywheel signal is used to estimate the torque at the flywheel and a test quantity is designed by weighting and thresholding the samples of estimated torque related to one combustion. During the development process, the Kullback-Leibler divergence is used to analyze the ability to detect a misfire given a test quantity and how the misfire detectability performance varies depending on, e.g., load and speed. The Kullback-Leibler divergence is also used for parameter optimization to maximize the difference between misfire data and fault-free data. Evaluation shows that the proposed misfire detection algorithm is able to have a low probability of false alarms while having a low probability of missed detections.

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  • 34.
    Eriksson, Daniel
    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.
    Frisk, Erik
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Krysander, Mattias
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Flywheel angular velocity model for misfire and driveline disturbance simulation2013In: Proceedings of the 7th IFAC Symposium on Advances in Automotive Control, The International Federation of Automatic Control, Elsevier, 2013, Vol. 46, no 21, p. 570-575Conference paper (Refereed)
    Abstract [en]

    A flywheel angular velocity model for misfire and disturbance simulation is presented. Applications of the model are, for example, initial parameter calibration and robustness analysis of misfire detection algorithms. An analytical cylinder pressure model is used to model cylinder torque and a multi-body model with torsional flexibilities is used to model crankshaft and driveline oscillations. Misfires, cylinder variations, changes in auxiliary load, and flywheel manufacturing errors can be injected in the model and the resulting speed variations can be simulated. A qualitative validation of the model shows that simulated angular velocity captures the amplitude and oscillatory behavior of measurement data and the effects of different phenomena, such as misfire and flywheel manufacturing errors.

  • 35.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    A European Perspective on Collaborative Research in Modeling and Control of Turbocharged Engines2014In: Journal of the Society of Instrument and Control Engineers, ISSN 0453-4662, Vol. 53, no 8, p. 716-724Article in journal (Refereed)
    Abstract [en]

    Modeling and simulation plays an important role in the design of the control systems for advanced power­trains. One clear trend is that turbocharged engines are becoming more common and are also being equipped with more than one boosting device. To systematicaUy handle these advanced turbocharging concepts we need to build more knowledge and this knowledge is encap­sulated in models. Recent results for modeling and control of compres­sors in advanced engines are provided.   In particular the experimental results from a large measurement cam-paign with engine and gas stand hardware an;\ sum­marized as rules of thumb extrapolating manufacturer compressor data. Thereafter, system properties öf V­engines with pa.rallel turbocharging is investigated and used to illustrate applications of the newly developed modeling knowledge. It is used to niodel, simulate and analyzc a compressor instability phenomenon that gives rise to an oscillation. A detection scheme and a con­troller is also developed and it is shown to quell the oscillation. Finally the benefits of academic and industrial collab­oration, that play an important role in the authors lab as well as in many European institutes, are commented upon. A concluding remark is that thc works that are summarized would not have been possible without the cooperation between academy and industry.

  • 36.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    A Real-Time Platform for Spark Advance Control1997Report (Other academic)
    Abstract [en]

    With the aim at spark advance control, a method for estimating the peak pressure position (PPP) from the ionization current has previously been developed and off-line validated. To implement the concept on an engine a real-time platform is needed. A hardware platform, that consists of a PC, an electronic engine control unit (ECU), and a synchronization circuit, is described. The platform synchronizes the data acquisition with the engine and the functionality is validated. Also a refined interpretation algorithm for estimating the PPP is described and validated to give a good estimate. The algorithm is suitable for implementation on the described real-time platform.

  • 37.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    An overview of various control benchmarks with a focus on automotive control2019In: Control Theory and Technology, ISSN 2095-6983, Vol. 17, no 2, p. 121-130Article in journal (Refereed)
    Abstract [en]

    There exists a gap between control theory and control practice, i.e., all control methods suggested by researchers are not implemented in real systems and, on the other hand, many important industrial problems are not studied in the academic research. Benchmark problems can help close this gap and provide many opportunities for members in both the controls theory and application communities. The goal is to survey and give pointers to different general controls and modeling related benchmark problems that can serve as inspiration for future benchmarks and then specifically focus the benchmark coverage on automotive control engineering application. In the paper reflections are given on how different categories of benchmark designers, benchmark solvers and third part users can benefit from providing, solving, and studying benchmark problems. The paper also collects information about several benchmark problems and gives pointers to papers than give more detailed information about different problems that have been presented.

  • 38.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    CHEPP – A Chemical Equilibrium Program Package for Matlab2005In: SAE technical paper series, ISSN 0148-7191, Vol. 4, no 113, p. 730-741Article in journal (Refereed)
    Abstract [en]

    A program package, that calculates chemical equilibrium and thermodynamic properties of reactants and products of a combustion reaction between fuel and air, has been developed and validated. The package consists of the following four parts: 1) A program for calculating chemical equilibrium. 2) A database that contains thermochemical information about the molecules, which comes from the GRI-Mech tables. 3) A GUI that allows the user to easily select fuels, fuel/air ratio for the reaction, and combustion products. 4) A set of functions designed to access the thermochemical database and the chemical equilibrium programs. Results are validated against both the NASA equilibrium program (Gordon and McBride, 1994) and the program developed by Olikara and Borman (1975). It is shown that the new method gives results identical to those well recognized Fortran programs.

  • 39.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Development of a Hardware and Software Platform that Constitutes a Step Towards Adaptive Engine Control1998Conference paper (Refereed)
  • 40.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Documentation for the Chemical Equilibrium Program Package CHEPP2000Report (Other academic)
    Abstract [en]

    A program package has been developed that calculates chemical equilibrium and thermodynamic properties of reactants and products of a combustion reaction between fuel and air. The package consists of the following four parts: 1) A program for calculating chemical equilibrium. 2) A database that contains thermochemical information about the molecules, which comes from the GRI-Mech tables. 3) A GUI that allows the user to easily select fuels, fuel/air ratio for the reaction, and combustion products. 4) A set of functions designed to access the thermochemical database and the chemical equilibrium programs. The program package is validated with respect to how well it can reproduce results shown in the standard literature. The thermodynamic properties for the individual molecules and the results from the equilibrium calculation all agree with the results shown in the literature. There is almost perfect agreement, between the results produced by the program package and those shown in the book by Heywood, when comparing the thermodynamic properties of the mixture of equilibrium products.

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    Documentation for the Chemical Equilibrium Program Package CHEPP
  • 41.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Increasing the Efficiency of SI-Engines by Spark Advance Control and Water Injection1997Report (Other academic)
    Abstract [en]

    By directly measuring in-cylinder parameters and adjusting the spark advance, the engine efficiency can be maximized. A feedback scheme for spark-advance control using the ionization current as sensed variable has earlier been presented. One issue is to verify that the algorithm works when the environmental conditions changes the burn rate. Humidity significantly affects the burn rate and active water injection is used to slow down the combustion giving a peak pressure position (PPP) that occurs too late. The ionization current based feedback-scheme adjusts the spark advance, and moves the PPP back to optimum. An additional result is that the engine efficiency can be increased by combining active supply of water to the combustion and the spark-advance control scheme.

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    Increasing the Efficiency of SI-Engines by Spark Advance Control and Water Injection
  • 42.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Les rencontres scientifiques d’IFP energies nouvelles RHEVE 2011: International Scientific Conference on Hybrid and Electric Vehicles2013In: Oil & Gas Science and Technology: Revue de l'Institut Français du Pétrole, ISSN 1294-4475, Vol. 68, no 1, p. 9-12Article in journal (Other academic)
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  • 43.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Mean Value Models for Exhaust System Temperatures2003In: SAE technical paper series, ISSN 0148-7191, Vol. 111, no 3Article in journal (Refereed)
    Abstract [en]

    Exhaust temperatures are important for turbine and catalyst performance. A set of exhaust temperature models suitable for turbo matching as well as design and analysis of engine control systems are developed and investigated. The models are lumped parameter heat transfer models, that fall within the category of mean value engine models. The model is developed for describing exit temperatures from the exhaust manifold and temperature drops in pipe sections in the exhaust system. The components used to model the exhaust temperature are: engine out temperature, temperature drop in a straight pipe, and a set of heat transfer modes. The model is validated using data from three different engines. It is shown that, for a spark ignited engine operating at MBT and stoichiometric conditions, it is sufficient to model the engine out temperature as a linear function of mass flow. Recommendations for tuning the model are also given. A thorough survey of exhaust heat transfer literature is also made together with a comparative summary of the different heat transfer modes that are present in the exhaust.

  • 44.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Methods for Ionization Current Interpretation to be Used in Ignition Control1995Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It is desirable to measure engine performance for several reasons, e.g. when computing the spark advance setting in spark-ignited (SI) engines. There exists two methods, among others, of measuring the performance, such as measuring the pressure and the ionization current. Since the ionization current reflects the pressure, it is interesting to study if it is possible to extract information from the ionization current about the combustion and pressure.

    Three different algorithms for extracting information from the ionization current are studied. The first algorithm, ion peak, searches the \second peak" in the ionization signal. The second algorithm computes the centroid. In the third algorithm a model of the ionization signal structure is fitted to the ionization signal.

    The algorithms are tested in four operating conditions. The first algorithm uses the local information around the second peak and is sensitive to noise. The second algorithm uses a larger portion of the ionization signal, which is more stable. It provides promising results for engines with a clear post flame phase. The third algorithm, ion structure analysis, fits an ideal model to the ionization signal. The algorithm provides promising results, but the present implementation requires much computational effort.

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    Methods for Ionization Current Interpretation to be Used in Ignition Control
  • 45.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Modeling and Control of Supercharged SI and CI Engines2006In: Proceedings of New Trends in Engine Control, Simulation and Modelling, 2006Conference paper (Refereed)
    Abstract [en]

    A component based modeling methodology for turbocharged engines is described and applied. Several component models are compiled and reviewed. In addition new models are developed for the compressor efficiency, compressor flow, and turbine flow. Two application examples are finally given where the modeling methodology and the component models have been used. The applications are: Observer design and air/fuel ratio control of SI engines. Control design of DI engines with VGT and EGR.

    CONFERENCE INFORMATION: Les Rencontres Scientifiques de l’IFP : "New Trends in Engine Control, Simulation and Modelling" 2-4 October 2006, IFP, Rueil-Malmaison, France

  • 46.
    Eriksson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Modeling and Control of Turbocharged SI and DI Engines2007In: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 62, no 4, p. 523-538Article in journal (Refereed)
  • 47.
    Eriksson, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Modeling and Control of Turbocharged SI and DI Engines2006Conference paper (Refereed)
  • 48.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Requirements for and a Systematic Method for Identifying Heat-Release Model Parameters1998In: SAE technical paper series, ISSN 0148-7191, Vol. 107, p. 898-908Article in journal (Refereed)
    Abstract [en]

    Heat release analysis by using a pressure sensor signal is a well recognized technique for evaluation of the combustion event, and also for combustion diagnostics. The analysis includes tuning of several parameters in order to accurately explain measured data. This work presents and investigates a systematic method for estimating parameters in heat release models and minimizing the arbitrary choices. In order for the procedure to be systematic there are also the requirements on the model, that it includes no inherent ambiguities, like over-parameterization with respect to the parameters and to the information contained in the measurements. The fundamental question is which parameters, in the heat release model, that can be identified by using only cylinder pressure data. The parameter estimation is based on established techniques, that constructs a predictor for the model and then minimizes a least-squares objective function of the prediction error. The study is performed on data measured on a SAAB 2.3 liter, four stroke four cylinder, normally aspirated, gasoline engine.

  • 49.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    Robustness analysis of dual actuator EGR controllers in marine two-stroke diesel engines2020In: Journal of Marine Engineering & Technology, ISSN 2046-4177, E-ISSN 2056-8487, Vol. 19, no sup1, p. 17-30Article in journal (Refereed)
    Abstract [en]

    Exhaust Gas Recirculation (EGR) was recently introduced in large marine two-stroke diesel engines to reduce NOx-emissions. Controlling EGR flow during accelerations, while keeping good acceleration performance is challenging, due to delays in the scavenge receiver oxygen measurement and upper limits on fuel for avoiding black smoke. Previous oxygen feedback controllers struggled during accelerations, but a new EGR-controller based on adaptive feedforward (AFF) has been successful. Nevertheless, further analysis and tests are required before deploying the controller to more EGR ships. A simulation platform is a great asset to test controllers before expensive real-world experiments are conducted. A new EGR flow controller is proposed and tested in a complete ship simulation model. Several acceleration scenarios show that the low load area is most challenging. Controller robustness is analysed in this area, showing that pressure sensor bias in the EGR flow estimator is the most critical factor, which could lead to black smoke formation. This can be prevented with sensor calibration or by using a differential pressure sensor. Errors in the parameters of the flow estimators are not as important. This is a useful result because the right parameters of the flow estimators might be difficult to obtain, on a new engine.

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  • 50.
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Simulation of a vehicle in longitudinal motion with clutch engagement and release2001Conference paper (Refereed)
    Abstract [en]

    A simple model for driver and vehicle in longitudinal motion is developed and simulated. The focus is on describing and handling simulation of clutch lock and clutch release which changes the model structure, both during start and gear shifts, in Simulink. Special attention is given the problem of simulating start and stop of a vehicle with rolling resistance at zero speed. Only principles for simulating the system with variable structure is of interest and therefore the models are maintained at lowest possible complexity. The system is successfully simulated and the validation is performed using three scenarios: one with only clutch lock and clutch release, one with start and stop of vehicle, and one full European drive-cycle.

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