@article{MichosBikas2020, author = {Michos, Konstantinos N. and Bikas, Georgios}, title = {Quasi-Dimensional Multi-Zone Combustion Diagnostic Tool for SI Engines with Novel NOx and CO Emissions Models}, series = {SAE International Journal of Advances and Current Practices in Mobility}, volume = {2}, journal = {SAE International Journal of Advances and Current Practices in Mobility}, number = {4}, publisher = {SAE International}, issn = {2641-9645}, doi = {https://doi.org/10.4271/2020-01-0289}, pages = {1818 -- 1848}, year = {2020}, abstract = {In this work a quasi-dimensional multi-zone combustion diagnostic tool for homogeneous charge Spark Ignition (SI) engines is analytically developed for the evaluation of heat release, flame propagation, combustion velocities as well as engine-out NOx and CO emissions, based on in-cylinder pressure data analysis. The tool can be used to assess the effects of fuel, design and operating parameters on the SI engine combustion and NOx and CO emissions formation processes. "Certain novel features are included in the presently developed combustion diagnostic tool. Firstly, combustion chambers of any shape and spark plug position can be considered due to an advanced model for the calculation of the geometric interaction between a spherically expanding flame and a general combustion chamber geometry. Also, the temperature stratification of the burned gas developed during the combustion phase, which has to be captured for the theoretically realistic estimation of the in-cylinder formation of pollutant emissions, is taken into account by a multi-zone thermodynamic treatment. According to this, multiple spherically allocated burned zones are sequentially generated at specified (user-defined) crank angle intervals, forming overlapping shells. Moreover, complex chemical equilibrium compositions are computed, which can include any user-defined mixture of species in the combustion products, using an advanced modular method based on the minimization of Gibbs energy. Furthermore, NOx and CO engine-out emissions are calculated based on novel in-cylinder formation models presented by the authors in the past. Specifically, NOx emissions are evaluated by a global algebraic NOx emissions formation model, accounting for both thermal and subO pathway NO formation, based on the calculation of the characteristic timescales of the relevant NO formation mechanisms. CO emissions are assessed using a new kinetics-based model, consisting of a single Ordinary Differential Equation (ODE) that can be analytically integrated. The CO emissions model is derived considering the dynamics of a representative pool of active radicals in post-flame gases and explicitly describes the CO oxidation quenching process. "The combustion diagnostic tool is applied to a lean burn gas engine at various engine speeds under full load conditions and constant lambda value. Various combustion and NOx and CO emissions related results are presented and discussed to illustrate the capabilities of the tool for combustion diagnosis, while at the same time calculated engine-out NOx and CO emissions are found to be in satisfactory agreement with measured ones.}, language = {en} } @article{GrossmannMuehlpfordtRambacheretal.2021, author = {Großmann, Fabian and M{\"u}hlpfordt, Torsten and Rambacher, Patrick and Bikas, Georgios}, title = {Crank-Angle Resolved Flow Measurements in the Intake Duct of a Research Engine Using Novel and Fast Response Aerodynamic Probes}, series = {Frontiers in Mechanical Engineering}, volume = {7}, journal = {Frontiers in Mechanical Engineering}, publisher = {Frontiers Media SA}, issn = {2297-3079}, doi = {https://doi.org/10.3389/fmech.2021.633690}, pages = {1 -- 15}, year = {2021}, abstract = {Despite the public debate nowadays on the future of Internal Combustion Engines (ICE), which is impeding their development, one limitation towards further optimization of ICE in terms of fuel consumption and emissions can be seen in the current approach and more specifically in the transient engine operation and its control. The main drawbacks in the current approach source from: 1) complex structure of mechanization including sensors and actuators, 2) low time resolution and accuracy of sensing (cost driven), 3) complex Electronic Control Unit (ECU)-software architecture associated with huge calibration effort and 4) recently, funded research due to unsecure business model of ICE is becoming less. To overcome these difficulties unexploited potential should be utilized. Some of this potential lies in cycle-by-cycle and cylinder-by-cylinder accurate fuel and air control, and in the development of physical based virtual sensors with high time resolution and accuracy. One of the main motivations for this study was to develop a measurement technique that enables crank-angle resolved air mass flow rate measurements during engine operation in a dynamometer test cell. The measurement principle is quite simple and is based on gauging the dynamic pressure in both the intake and exhaust duct at the closest possible positions to the valves. To fulfill these requirements aerodynamic probes have been developed and manufactured utilizing 3D printing. The probes have been integrated in special developed flanges, which correspond exactly to the shape of the air channels in the cylinder head of the engine. Hence, they can be mounted either in front of the valves at the intake or behind the valves at the exhaust duct. Results at different engine operating conditions have been obtained, analyzed and correlated to other sensors like air-flow meter. Those post-processed results can be further used to validate 1-D gas exchange models, or 3-D Computational Fluid Dynamics (CFD) port flow models. The ultimate scope of these measurements is to calibrate fast physical-based gas exchange models that can be directly used in the engine control framework on an embedded system.}, language = {en} } @inproceedings{BikasWeigandBrilzetal.2020, author = {Bikas, Georgios and Weigand, Peter and Brilz, Marina and Michos, Konstantinos}, title = {High Resolution Global NOx Sub-Model for Embedded System Application with Low Calibration Effort}, series = {SAE Technical Paper Series}, booktitle = {SAE Technical Paper Series}, publisher = {SAE International}, address = {400 Commonwealth Drive, Warrendale, PA, United States}, issn = {0148-7191}, doi = {https://doi.org/10.4271/2020-01-0246}, year = {2020}, language = {en} } @article{KoegelPflitschNorthupetal.2022, author = {K{\"o}gel, Michael and Pflitsch, Andreas and Northup, Diana E. and Carstensen, Dirk and Medley, Joseph J. and Mansheim, Teresa and Killing, Thomas and Buschbacher, Michael and Angerer, Helena and Falkner, Julian and Kynatidis, Achilleas and Ott, Valentin and Regler, Simon}, title = {Combination of close-range and aerial photogrammetry with terrestrial laser scanning to answer microbiological and climatological questions in connection with lava caves}, series = {Applied Geomatics}, volume = {14}, journal = {Applied Geomatics}, number = {4}, publisher = {Springer Science and Business Media LLC}, issn = {1866-9298}, doi = {https://doi.org/10.1007/s12518-022-00459-7}, pages = {679 -- 694}, year = {2022}, abstract = {Combining photogrammetric reconstruction (close-range photogrammetry, CRP) and airborne photogrammetry through the structure from motion method (SFM) with terrestrial three-dimensional (3D) laser scanning (TLS), Maelstrom Cave on Big Island, Hawaii (USA), was mapped in three dimensions. The complementary properties of the two methods generated an overall model that depicted significant features of the cave both spatially and visually. Through various processes, the complex geometric quantities were derived from the model that can be used to answer microbiological and climatological questions. In this report, the procedure for the three-dimensional acquisition of the terrain surface above Maelstrom Cave as well as the interior of the cave with TLS and SFM is described. It is shown how the different data sets were combined and contrasted, including a comparison of geometries from the different survey operations. Finally, the editing processes used to quantify and simplify the cave geometry are presented, as well as the analysis of the ellipses generated accordingly to determine the geometric quantities. Through the analysis of the cave geometry, important geometric properties of the Maelstrom Cave could be quantified and categorized. In this way, an effective tool was developed to directly correlate the structure of the cave system with climatological and microbiological parameters in order to answer the corresponding questions.}, language = {en} } @inproceedings{BetzoldDentel2021, author = {Betzold, Christina and Dentel, Arno}, title = {Evaluation and test operation of different model predictive control approaches for an energy system}, series = {Proceedings of the 17th IBPSA Conference : Bruges, Belgium, Sept. 1-3, 2021}, booktitle = {Proceedings of the 17th IBPSA Conference : Bruges, Belgium, Sept. 1-3, 2021}, publisher = {KU Leuven}, issn = {2522-2708}, doi = {https://doi.org/10.26868/25222708.2021.30597}, pages = {326 -- 333}, year = {2021}, language = {en} } @inproceedings{DentelBetzold2021, author = {Dentel, Arno and Betzold, Christina}, title = {Activation of the building thermal mass to store PV surplus energy}, series = {Proceedings of the 17th IBPSA Conference : Bruges, Belgium, Sept. 1-3, 2021}, booktitle = {Proceedings of the 17th IBPSA Conference : Bruges, Belgium, Sept. 1-3, 2021}, publisher = {KU Leuven}, issn = {2522-2708}, doi = {https://doi.org/10.26868/25222708.2021.31141}, pages = {673 -- 679}, year = {2021}, language = {en} } @inproceedings{SchierEppleMaaouietal.2020, author = {Schier, Michael and Epple, Fabius and Maaoui, Aicha and Schwellinger, Martin and Weber, Michael and Dietz, Armin and Zimmermann, Rolf}, title = {Development of a Two In One Motor System as a new Vehicle Energy Concept for Next Generation Car}, series = {2020 Fifteenth International Conference on Ecological Vehicles and Renewable Energies (EVER)}, booktitle = {2020 Fifteenth International Conference on Ecological Vehicles and Renewable Energies (EVER)}, publisher = {IEEE}, doi = {https://doi.org/10.1109/ever48776.2020.9243148}, pages = {12}, year = {2020}, language = {en} } @article{SeissThielEichelbaum2022, author = {Seiß, Volker and Thiel, Susanne and Eichelbaum, Maik}, title = {Preparation and Real World Applications of Titania Composite Materials for Photocatalytic Surface, Air, and Water Purification: State of the Art}, series = {Inorganics}, volume = {10}, journal = {Inorganics}, number = {9}, publisher = {MDPI AG}, issn = {2304-6740}, doi = {https://doi.org/10.3390/inorganics10090139}, year = {2022}, abstract = {The semiconducting transition metal oxide TiO2 is a rather cheap and non-toxic material with superior photocatalytic properties. TiO2 thin films and nanoparticles are known to have antibacterial, antiviral, antifungal, antialgal, self, water, and air-cleaning properties under UV or sun light irradiation. Based on these excellent qualities, titania holds great promises in various fields of applications. The vast majority of published field and pilot scale studies are dealing with the modification of building materials or generally focus on air purification. Based on the reviewed papers, for the coating of glass, walls, ceilings, streets, tunnels, and other large surfaces, titania is usually applied by spray-coating due to the scalibility and cost-efficiency of this method compared to alternative coating procedures. In contrast, commercialized applications of titania in medical fields or in water purification are rarely found. Moreover, in many realistic test scenarios it becomes evident that the photocatalytic activity is often significantly lower than in laboratory settings. In this review, we will give an overview on the most relevant real world applications and commonly applied preparation methods for these purposes. We will also look at the relevant bottlenecks such as visible light photocatalytic activity and long-term stability and will make suggestions to overcome these hurdles for a widespread usage of titania as photocalyst.}, language = {en} } @inproceedings{DietzCarusoDiTommasoetal.2020, author = {Dietz, Armin and Caruso, M. and Di Tommaso, A. O. and Miceli, R. and Nevoloso, C.}, title = {Enhanced Mathematical Modelling of Interior Permanent Magnet Synchronous Machine Considering Saturation, Cross-Coupling and Spatial Harmonics effects}, series = {2020 Fifteenth International Conference on Ecological Vehicles and Renewable Energies (EVER)}, booktitle = {2020 Fifteenth International Conference on Ecological Vehicles and Renewable Energies (EVER)}, publisher = {IEEE}, doi = {https://doi.org/10.1109/ever48776.2020.9243003}, pages = {9}, year = {2020}, abstract = {The Interior Permanent Magnet Synchronous machine (IPMSM) conventional mathematical model is generally employed to investigate and simulate the IPMSM control and drive system behaviour. However, magnetic nonlinearities and spatial harmonics have a substantial influence on the IPMSM electromagnetic behaviour and performances. In order to simulate the IPMSM real electromagnetic behaviour, this paper describes an enhanced mathematical model that takes into account the saturation, cross-coupling and spatial harmonics effects. This model has been implemented in Matlab®/Simulink environment where the electric and magnetic parameters are derived from FEA investigations and implemented by the use of lookup tables. The high fidelity of the proposed IPMSM Simulink model is validated by the results of the FEA investigations carried out.}, language = {en} } @inproceedings{ZocherStarostGrassetal.2023, author = {Zocher, Markus and Starost, Veit and Grass, Norbert and Schmidt, Michael and Wilfling, Timo}, title = {High Bandwidth Integrator for Differential, PCB Integrated Rogowski Coils}, series = {2023 International Conference on Electrical Drives and Power Electronics (EDPE)}, booktitle = {2023 International Conference on Electrical Drives and Power Electronics (EDPE)}, publisher = {IEEE}, doi = {10.1109/EDPE58625.2023.10274019}, pages = {1 -- 8}, year = {2023}, abstract = {This paper provides an accurate and high-bandwidth current measurement method, using a differential, PCB integrated Rogowski coil. This measurement is ideal for switching characterization of wide-bandgap semiconductors, which are progressively improving switching speeds of power electronic circuits and require a PCB design with low parasitic inductance. A design workflow for system integration of a differential Rogowski coil, including the necessary signal processing circuits onto a printed circuit board is provided. Different parasitic effects have been analyzed, and an amplifier topology for high bandwidth and superior Common Mode rejection is presented. The calculations are verified by simulation and measurements.}, language = {en} }