@misc{AltmannRablGaderer, author = {Altmann, Robert and Rabl, Hans-Peter and Gaderer, Matthias}, title = {Ph{\"a}nomenologische Untersuchung des Einspritzverhaltens von Pflanzen{\"o}lkraftstoff}, series = {3. Tagung der Fuels Joint Research Group (FJRG) "Kraftstoffe f{\"u}r die Mobilit{\"a}t von Morgen"}, journal = {3. Tagung der Fuels Joint Research Group (FJRG) "Kraftstoffe f{\"u}r die Mobilit{\"a}t von Morgen"}, language = {de} } @misc{SchwanzerDietrichHaftetal., author = {Schwanzer, Peter and Dietrich, Markus and Haft, Gerhard and Gaderer, Matthias and Rabl, Hans-Peter}, title = {Oxidation Kinetics Determination of GDI Engine Soot by a Radio-Frequency Sensor}, series = {23rd Conference on Combustion Generated Nanoparticles 2019, June 17-20, Z{\"u}rich, Switzerland}, journal = {23rd Conference on Combustion Generated Nanoparticles 2019, June 17-20, Z{\"u}rich, Switzerland}, language = {en} } @misc{OetjenRiegerRabletal., author = {Oetjen, Arne and Rieger, Anna and Rabl, Hans-Peter and van de Par, Steven}, title = {The role of dissonance in the sound quality perception for electric vehicles}, series = {The Journal of the Acoustical Society of America}, volume = {148}, journal = {The Journal of the Acoustical Society of America}, number = {4}, publisher = {Acoustical Society of America}, doi = {10.1121/1.5147356}, abstract = {Tonal components can be regarded as one of the most relevant components for interior sound quality of electric vehicles, especially at low speeds. Sources for these tones are for example the vehicles' drivetrains but also other technical components. Depending on the driving conditions, due to the interaction of various dominant sources, audible tone complexes can occur. Similar to musical intervals, the different frequency ratios within these complexes can result in consonant or dissonant sensations. The strength of this sensation does not only depend on the frequency relation of the tones but also on their relative levels. In this study, different musical intervals were subjectively rated in terms of their specific consonant or dissonant character. Using an adaptive procedure, sound pairs, each consisting of a two-tone signal, where adjusted to equal dissonance by varying the level of the second tone of one of the two-tone signals. Using the same paradigm, also pairs of equal vehicle sound quality were obtained. With these results, it is possible to quantify dissonance, and theinfluence of dissonance on sound quality expressed in terms of level differences of two-tone signals. These results can help to make the concept of dissonance more useful for sound-engineering applications.}, language = {en} } @article{KoderSchwanzerZacherletal., author = {Koder, Alexander and Schwanzer, Peter and Zacherl, Florian and Rabl, Hans-Peter and Mayer, Wolfgang and Gruber, Georg and Dotzer, Thomas}, title = {Combustion and emission characteristics of a 2.2L common-rail diesel engine fueled with jatropha oil, soybean oil, and diesel fuel at various EGR-rates}, series = {Fuel}, volume = {228}, journal = {Fuel}, number = {September}, publisher = {Elsevier}, doi = {10.1016/j.fuel.2018.04.147}, pages = {23 -- 29}, abstract = {To investigate the combustion and emission behavior of straight vegetable oils (SVO), jatropha oil, soybean oil, and diesel fuel were tested. For this research, a 2.2L common-rail engine with a two-stage turbocharging concept was equipped with a cylinder pressure indication system, an exhaust-gas analyzer, an AVL Micro Soot sensor and a Scanning Mobility Particle Sizer 3936 (SMPS) device to detect the particle-size-distribution (PSD). At a low and mid-load engine-operating point (EOP), the thermodynamic and emissions were investigated under various exhaust gas recirculation (EGR) rates with respect to the PSD. Moreover, the injection behavior of the three test fuels was analyzed separately using an injection rate analyzer. This procedure facilitates the thermodynamic investigations of the engine process and allows the calculation of the hydraulic delay (HD) as well as the ignition delay (ID). The ID of the SVO fuels compared to diesel fuel was found to be lower at all engine-operating modes, while jatropha oil always showed the shortest ID. In the particulate-nitrogen oxide (NOX) trade-off, the SVO fuels showed higher particulate matter (PM) emissions at the low-load EOP, whereas the PM emissions of diesel fuel overtop the SVO fuels at a higher engine load. With increased EGR-rates, a rise in the particle size was observed for all fuels. At the low-load EOP, the SVO fuels showed larger particles for high EGR-rates. This effect also changed by increasing the engine-load to the mid-load EOP, wherein the particle size of the diesel fuel emissions is higher by applying elevated EGR-rates.}, language = {en} } @inproceedings{KoderZacherlRabletal., author = {Koder, Alexander and Zacherl, Florian and Rabl, Hans-Peter and Mayer, Wolfgang and Gruber, Georg and Dotzer, Thomas}, title = {Jatropha Oil as an Alternative Fuel for Modern Diesel Engines - Injection Characteristics and EGR-Compatibility}, series = {WCX 17: SAE World Congress 2017}, booktitle = {WCX 17: SAE World Congress 2017}, publisher = {SAE International}, doi = {10.4271/2017-01-5000}, abstract = {An effective way to reduce greenhouse gas emissions (GHGs) is to use rurally produced straight jatropha oil as a substitute for diesel fuel. However, the different physical and chemical properties of straight vegetable oils (SVOs) require a customized setup of the combustion engine, particularly of the injection timing and quantity. Therefore, this study demonstrates the differences in the injection and combustion processes of jatropha oil compared to diesel fuel, particularly in terms of its compatibility with exhaust gas recirculation (EGR). A 2.2 l common-rail diesel engine with a two-stage turbocharging concept was used for testing. To examine the differences in injection rate shaping of diesel fuel and jatropha oil, the injector was tested with an injection rate analyzer using both the fuels. To investigate the combustion process, the engine was mounted at an engine test bench and equipped with a cylinder pressure indication system. All limited emissions, as well as fuel consumption, were measured. Various injection strategies, boost and rail pressure levels were tested at different EGR rates in terms of their impact on the combustion process. EGR in particular offers a great potential in the case of jatropha oil combustion due to its oxygen content. In addition, the investigation of injection rate shaping in combination with cylinder pressure analysis allowed a detailed thermodynamic evaluation of the combustion process. Ignition delay (ID) was also analyzed using a new method to calculate the start of combustion (SOC)}, language = {en} } @article{WalterSchwanzerSteineretal., author = {Walter, Stefanie and Schwanzer, Peter and Steiner, Carsten and Hagen, Gunter and Rabl, Hans-Peter and Dietrich, Markus and Moos, Ralf}, title = {Mixing Rules for an Exact Determination of the Dielectric Properties of Engine Soot Using the Microwave Cavity Perturbation Method and Its Application in Gasoline Particulate Filters}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {9}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/s22093311}, pages = {1 -- 17}, abstract = {In recent years, particulate filters have become mandatory in almost all gasoline-powered vehicles to comply with emission standards regarding particulate number. In contrast to diesel applications, monitoring gasoline particulate filters (GPFs) by differential pressure sensors is challenging due to lower soot masses to be deposited in the GPFs. A different approach to determine the soot loading of GPFs is a radio frequency-based sensor (RF sensor). To facilitate sensor development, in previous work, a simulation model was created to determine the RF signal at arbitrary engine operating points. To ensure accuracy, the exact dielectric properties of the soot need to be known. This work has shown how small samples of soot-loaded filter are sufficient to determine the dielectric properties of soot itself using the microwave cavity perturbation method. For this purpose, mixing rules were determined through simulation and measurement, allowing the air and substrate fraction of the sample to be considered. Due to the different geometry of filter substrates compared to crushed soot samples, a different mixing rule had to be derived to calculate the effective filter properties required for the simulation model. The accuracy of the determined mixing rules and the underlying simulation model could be verified by comparative measurements on an engine test bench.}, language = {en} } @inproceedings{KasparKleinerRabl, author = {Kaspar, Marcel and Kleiner, Florian and Rabl, Hans-Peter}, title = {Online-Analyse und Optimierung der Schmier{\"o}lverd{\"u}nnung bei direkteinspritzenden Ottomotoren}, series = {7. VDI-Fachtagung mit Fachausstellung Zylinderlaufbahn, Kolben, Pleuel : Baden-Baden, 03. und 04. Juni 2014}, booktitle = {7. VDI-Fachtagung mit Fachausstellung Zylinderlaufbahn, Kolben, Pleuel : Baden-Baden, 03. und 04. Juni 2014}, publisher = {VDI-Verlag}, address = {D{\"u}sseldorf}, isbn = {978-3-18-092230-0}, pages = {65 -- 77}, abstract = {Bei Ottomotoren mit Direkteinspritzung besteht beim Kaltstart, den Warmlaufphasen und auch durch den Einfluss anderer Parameter wie z. B. des Einspritzzeitpunkts oder des Einspritzdrucks die Problematik, dass Kraftstoff an die Zylinderlaufbahn aufgetragen wird und sich mit dem Motor{\"o}l vermischen kann. Eine Verst{\"a}rkung dieses Kraftstoffauftrags ist unter anderem der Verschiebung der Motorbetriebspunkte zu h{\"o}heren Mitteldr{\"u}cken und damit einem Wirkungsgrad optimaleren Betrieb geschuldet. Eine Ver{\"a}nderung der physikalischen und chemischen Eigenschaften des Motor{\"o}ls durch die Verd{\"u}nnung mit Kraftstoff ist die Folge. Durch die Verringerung der Viskosit{\"a}t des Motor{\"o}ls kann es zu einer verminderten Schmierwirkung des {\"O}ls kommen, die im schlimmsten Fall zur Sch{\"a}digung des Motors f{\"u}hrt. Existierende Offline-Analysemethoden die zeitintensive Laboranalysen nach sich ziehen, als auch Online-Messverfahren die nicht den technischen Anforderungen hinsichtlich Genauigkeit und einer kurzen Messdauer entsprechen, stellen aktuell die einzigen Messmethoden zur Bestimmung der Schmier{\"o}lverd{\"u}nnung dar. Durch neue Entwicklungstrends bei Ottomotoren ist es jedoch unbedingt notwendig, die Mechanismen des Kraftstoffein- und -austrags in das und aus dem Motor{\"o}l genauer zu untersuchen. Mit der an der OTH Regensburg neu entwickelten Messtechnik wurde eine Vorgehensweise erarbeitet, mit der die zeitlichen Verl{\"a}ufe des Kraftstoffein- und -austragsverhaltens bei Ottomotoren quantitativ in kurzer Zeit bestimmt und optimiert werden k{\"o}nnen. Especially at cold start and the warm-up operation GDI engines have an issue with oil dilution. Parameters such as injection timing and injection pressure impact the entry of fuel in the engine oil as well. With the adjustment of engine operating points to higher mean effective pressures resulting in downsizing concepts also an additional increase of fuel entry occurs. Fuel gets into the oil pan and is mixed with the engine oil so that the physical and chemical properties of the engine oil are changed. With the reduction of engine oil viscosity due to fuel entry a reduced lubricating effect can be caused. In the worst case damage to the engine occurs, To determine oil dilution online and offline measurement methods exist. A rather long analysis time in the laboratory is a disadvantage of the offline methods. Online methods are not correlating with technical requirements in terms of accuracy and a short measurement time. New trends in the development of gasoline engines require investigations of fuel in oil sorption and desorption processes. A new measurement technique which is developed at the OTH Regensburg enables to determine quantitative fuel in oil sorption and desorption processes. With this technique a procedure was generated to measure the oil dilution at gasoline engines and optimize them in a short time.}, language = {de} } @article{SchwanzerRablLodersetal., author = {Schwanzer, Peter and Rabl, Hans-Peter and Loders, S. and Seifert, P. and Himmelstoss, S. and Gaderer, Matthias}, title = {Difference in the Tailpipe Particle Number by Consideration of Sub-23-nm Particles for Different Injection Settings of a GDI Engine}, series = {Emission control science and technology}, volume = {5}, journal = {Emission control science and technology}, number = {1}, publisher = {Springer Nature}, doi = {10.1007/s40825-019-0114-1}, pages = {7 -- 22}, abstract = {The purpose of this study was to investigate the characteristic of nanoparticles under consideration of sub-23-nm particles from a 1.8-l direct injection (DI) gasoline engine under stoichiometric air/fuel conditions in the exhaust gas system. For future CO2 challenges, the usage of DI-instead of port fuel injection (PFI)-gasoline engines is unavoidable. Therefore, a state of the art particle management program-particle number (PN) system, the Horiba SPCS (2100) with an integrated CPC (condensation particle counter), was recalibrated from a 50\% cutoff (D-50\%) at 23 nm down to a cutoff at 10 nm and the PCRF (particle concentration reduction factor) for sizes smaller than 23 nm was checked. Two different modal points, out of a representative Real Driving Emission (RDE) cycle, were investigated with both calibrations, D-50\%=10 nm and D-50\%=23 nm. For these different load points, the fuel pressure (FUP) and the start of injection (SOI) were varied, to represent the difference in the structure and the ratio conc((10 nm))/conc((23 nm)) of the nanoparticle emissions. The particle characterization includes the particle number (PN), the particle size distribution (PSD), and the particle mass (PM). The particle number was measured with Horiba SPCS (2100). The particle size distribution was analyzed with a Grimm differential mobility analyzer (DMA) in combination with a Faraday cup electrometer (FCE). Micro Soot and Pegasor were used to determine the PM, and an optical characterization was done with a 120-kV Phillips CM12 transmission electron microscope (TEM). The position of all particle measurement systems was downstream the three-way catalyst (TWC). The results of this investigation showed that a higher injection pressure decreases the PN (without consideration of sub-23-nm particles) in general. The ratio conc((10 nm))/conc((23 nm)) was therefore higher, because smaller particles, especially ash particles, were less reduced from the FUP. This means higher FUP tends to a higher ratio. For the SOI, the main reasons of the ratio differences were explained by an encroachment between the injection jet and the piston, the valve and the wall.}, language = {en} } @article{SchwanzerSchillingerMieslingeretal., author = {Schwanzer, Peter and Schillinger, Maximilian and Mieslinger, Johann and Walter, Stefanie and Hagen, Gunter and Maerkl, Susanne and Haft, Gerhard and Dietrich, Markus and Moos, Ralf and Gaderer, Matthias and Rabl, Hans-Peter}, title = {A Synthetic Ash-Loading Method for Gasoline Particulate Filters with Active Oil Injection}, series = {SAR International Journal of Engines}, volume = {14}, journal = {SAR International Journal of Engines}, number = {4}, publisher = {SAE International}, issn = {1946-3936}, doi = {10.4271/03-14-04-0029}, pages = {493 -- 506}, abstract = {To reduce particulate emissions, the use of particulate filters in diesel engines is meanwhile state of the art, while the integration of such systems in gasoline engines is now also necessary in order to comply with today's regulations. Over its lifetime, a gasoline particulate filter (GPF) collects ash components of fuel, lubrication oil, and materials originating from the catalytic coating and from engine abrasion. In the development and application process, synthetic ashing from GPFs is challenging. The ash of the lubrication oil can be increased in various ways, like oil-doped fuel, a separate oil burner, or changes in the piston-cylinder system of the engine. However, these methods show major disadvantages. For this reason, an improved approach is presented in this study, which allows a quick response to changes in combustion (e.g., engine knocking) and producing ash, which is more realistic due to its primary particle size and the density of ash plugs, in a shorter time. Therefore, an approach to accelerate ash loading by active oil injection using a multi-point injection (MPI) system is introduced. With the help of this methodology, an ashing capacity of 1.21 g/h is implemented, which is a high rate compared to other investigations. The primary particle size (evaluated by means of a transmission electron microscope), is in the same size range as those detected at the full-load curve during regular operation. A computer tomographic (CT) analysis of the incinerated particulate filter also shows that a very high density of ash plugs can be realized, which has also been found in the literature for real applications. In addition, with the help of a mass spectrometer (MS) and an intermediate weighing of the particulate filter, the current ash loading of the GPF could be determined with an accuracy of 1\%.}, language = {en} } @article{BraunDurnerRabletal., author = {Braun, Peter and Durner, Bernhard and Rabl, Hans-Peter and Matysik, Frank-Michael}, title = {Investigations on the decomposition of AdBlue urea in the liquid phase at low temperatures by an electrochemically induced pH shift}, series = {Monatshefte f{\"u}r Chemie}, volume = {150}, journal = {Monatshefte f{\"u}r Chemie}, number = {9}, publisher = {Springer}, doi = {10.1007/s00706-019-02406-6}, pages = {1633 -- 1641}, abstract = {Ammonia-based selective catalytic reduction (SCR) systems are the most widely used technology for reduction of nitrogen oxide emissions from lean-burn engines such as diesel engines. However, at low exhaust temperatures, the SCR process is limited by difficulties in the decomposition of the ammonia precursor urea, which is carried on-board using an aqueous solution "AdBlue". In this study, the decomposition of AdBlue urea induced by electrical current and the resulting associated pH shifts were investigated in a divided cell configuration in the liquid phase. The decomposition was found to be favored in both electrochemical compartments, anodic and cathodic, at temperatures of 60-80 degrees C compared to a reference without electrochemical treatment. In addition to the determination of ammonia contents using an ammonia sensor, IC/HPLC analyses were carried out for each sample. Different side products such as biuret, nitrate, cyanuric acid, ammelide, and others were formed. In the anodic compartment, nitrate formation could be observed due to oxidation of ammonia at the electrode surface. [GRAPHICS] .}, language = {en} } @article{BraunRablMatysik, author = {Braun, Peter and Rabl, Hans-Peter and Matysik, Frank-Michael}, title = {Investigations on the Liquid-Phase Decomposition of AdBlue Urea for the Selective Catalytic Reduction Process}, series = {Chemie Ingenieur Technik}, volume = {91}, journal = {Chemie Ingenieur Technik}, number = {7}, publisher = {Wiley}, doi = {10.1002/cite.201800055}, pages = {961 -- 968}, abstract = {Difficulties in decomposing AdBlue to ammonia limit the applicability of selective catalytic reduction systems at low exhaust temperatures. Investigations on the decomposition of AdBlue in the liquid phase under elevated pressure at temperatures up to 165 degrees C were carried out. Besides effects of inorganic catalysts, the impact of pH on urea decomposition was examined. After dissolution in aqueous phase, the compounds ZnO, WO3, and MoO3 were found to be effective in liquid-phase AdBlue decomposition. However, the efficiency was dropping significantly over few hours. Decomposition of AdBlue urea was also found to be favored for alkaline and acidic conditions.}, language = {en} } @techreport{ZacherlWopperMieslingeretal., author = {Zacherl, Florian and Wopper, Christoph and Mieslinger, Johann and Peis, Michael and Rabl, Hans-Peter}, title = {Schlussbericht zum Verbundvorhaben NAMOSYN: Nachhaltige Mobilit{\"a}t durch synthetische Kraftstoffe}, address = {Regensburg}, pages = {156}, abstract = {Im Labor f{\"u}r Verbrennungsmotoren und Abgasnachbehandlung der OTH-Regensburg sollten im Zuge des NAMOSYN-Projektes zwei Vertreter klimaneutraler Kraftstoffe an verschiedenen Systempr{\"u}fst{\"a}nden (Motor-, Einspritzpr{\"u}fstand, optisch zug{\"a}ngliche Einspritzkammer, …) und mit Hilfe von Simulationsmethoden f{\"u}r den Einsatz in bestehenden Verbrennungsmotoren untersucht werden. Synthetische Kraftstoffe aus der Gruppe der Oxymethylenether (OME) stellen eine CO2-neutrale Alternative zu fossilem Dieselkraftstoff dar. F{\"u}r Ottomotoren wurde untersucht, ob der synthetische Kraftstoff DMC/MeFo (Dimethylcarbonat \& Methylformiat) einen Ersatz f{\"u}r Ottokraftstoff darstellen kann, bzw. eine Drop-In-F{\"a}higkeit gegeben ist. Die OTH Regensburg bearbeitete 2 unabh{\"a}ngige Teilvorhaben zur motorischen Testung von synthetischen Kraftstoffen: „FC 1A: Motorische Testung von OME" und „FC 2: Untersuchung von C1-Oxygenaten f{\"u}r Ottomotoren". Die Projektlaufzeit betrug 3,5 Jahre, inkl. kostenneutraler Verl{\"a}ngerung um 6 Monate aufgrund der Corona-Pandemie. Im FC1A "AP2-Nachr{\"u}stung Dieselmotoren" der OTH Regensburg lag der Fokus auf der Erforschung der Potentiale und der Umr{\"u}stung eines Einzylinder-Dieselmotors mit Pumpe-Leitung-D{\"u}se-(PLD)-Einspritzsystem des Projektpartners Motorenfabrik Hatz GmbH und Co. KG f{\"u}r OME-Betrieb. Im AP2.1 wurden umfangreiche Daten gesammelt und Simulationsmodelle des Motors und PLD-Einspritzsystems erstellt und mit Dieselkraftstoff und OME validiert. Nachfolgend wurden Parameterstudien zur Geometrie des Einspritzsystems und der physikalischen Eigenschaften von OME durchgef{\"u}hrt. In AP2.2 und AP2.3 wurden umfangreiche Untersuchungen an einem Motor- und Einspritzsystempr{\"u}fstand mit Diesel und OME durchgef{\"u}hrt und der Steuerger{\"a}tedatensatz f{\"u}r den OME-Betrieb optimiert. Die Ergebnisse zeigen, dass die Umstellung des Kraftstoffs auf OME, insbesondere bei einfachen Motoren mit rudiment{\"a}rer Einspritztechnik und ohne Mittel zur NOx-Reduzierung (keine AGR oder SCR), ein enormes Potenzial zur Steigerung des Wirkungsgrads bei gleichzeitiger Reduzierung aller regulierten Schadstoffe (NOx, 𝑃N, 𝑃M, CO und 𝑉OC) er{\"o}ffnet. Die Ergebnisse und generierten Simulationsmodelle unterst{\"u}tzen eine schnelle Serienentwicklung und Einf{\"u}hrung von OME-Umr{\"u}stl{\"o}sungen. In FC 2 werden die vielversprechenden Kraftstoffe Methylformiat (MeFo) und Dimethylcarbonat (DMC) motorisch getestet. Untersuchungen am Kraftstoffsystem und wichtigen Komponenten dienen als Grundlage f{\"u}r das AP3. Im AP3 wird die Machbarkeit der DMC/MeFo-Verbrennung am Vollmotor demonstriert und die erwarteten Emissionsvorteile gegen{\"u}ber herk{\"o}mmlichen Ottokraftstoffen gezeigt. Abweichend von der urspr{\"u}nglichen Planung werden an der OTH Regensburg Kraftstoffblends aus Benzin und MeFo untersucht, um den Einsatzbereich des Kraftstoffs zu erweitern. In AP5 werden potentielle Mischungsverh{\"a}ltnisse analysiert und die Eigenschaften der ausgew{\"a}hlten Kraftstoffmischungen an einem Einspritzratenpr{\"u}fstand, an der Einspritzkammer und am Vollmotor untersucht. Es werden Einspritzverhalten, Gemischaufbereitung und Abgasemissionen bewertet. Zudem wird eine Kraftstoffmischanlage entwickelt und ein optischer Zugang am Vollmotor erm{\"o}glicht. Eine {\"O}lverd{\"u}nnungsmesstechnik wird eingesetzt, um den Kraftstoffeintrag ins Motor{\"o}l zu untersuchen}, language = {de} }