Roland Wanker

Multi-Scale SCR Modeling, 1D Kinetic Analysis and 3D System Simulation

Future emission limits of diesel engines require additional effort for developing adequate and advanced exhaust gas aftertreatment devices. Urea-SCR systems are a promising approach to reduce nitric oxide emissions. Computer models as a complementary tool to experimental investigations help to make design decisions and to shorten the development process. Therefore, this work presents a comprehensive SCR simulation approach. All relevant conversion reactions are studied in a 1d model. The obtained parameters are transferred to 3d simulations and combined with a detailed description of the urea injection. Validation simulations are performed for the individual SCR reactions and show good agreement with experimental data. 1d studies of different SCR assemblies and sizes are presented. Full 3d simulations of an HSO system considering injection, homogeneous gas phase and catalytic reaction show the interaction of all relevant effects and their impact on the overall deNOx performance.

Case study: visual analysis of complex, time-dependent simulation results of a diesel exhaust system

In previous work we have presented visualization techniques that provide engineers with a high degree of interactivity and flexibility for analyzing large, time-dependent, and high-dimensional data sets resulting from CFD (computational fluid dynamics) simulations. In this case study we apply our techniques in the fields of the automotive engineering industry and demonstrate how users benefit from using them during their routine analysis, as well as for exploring new phenomena. For coping with some of the special requirements in this application, we adapted and extended parts of the system. A comparison of two related cases of a diesel exhaust system is presented, and some important questions about these cases are addressed.

Optimization of a 5-Step Kinetic Scheme for HCCI Applications

In this paper a reduced kinetic scheme adapted and optimized for HCCI applications is presented. This kinetic scheme uses three reactions for the low temperature oxidation and two reactions for the high temperature oxidation. In this work, the 5-step kinetic scheme is optimized using a genetic algorithm for two different sets of HCCI conditions : a near stoichiometric combustion with a high amount of exhaust gas recirculation and a lean combustion with no exhaust gas recirculation. The merit function used to perform the optimization is based on the comparison of the ignition delay calculated with the reduced scheme and a detailed kinetic scheme of reference. In this study, twelve parameters of the 5-step kinetic scheme are optimized for the two sets of HCCI conditions chosen. Finally, the reduced kinetic scheme is implemented in the 3D code FIREV8 and a fairly good agreement is obtained with experimental HCCI results. These results were found to be very promising for the future use of this 5-step kinetic model in a 3D code to study easily a large number of HCCI engine parameters.

Impact of varying ambient conditions during RDE on the measurement result of the AVL Gas PEMS iS

This paper discusses the qualification of the AVL 492 Gas PEMS iS for RDE measurements. The Gas PEMS iS is a mobile measurement device for gaseous components in the exhaust gas of combustion engines especially under real driving conditions. RDE boundary conditions are varying ambient temperature and humidity and also atmospheric pressure variations due to altitude changes.

1D/3D simulation workflow@@@1D/3D-Simulations-Workflow: Optimization of exhaust gas aftertreatment devices@@@Optimierung von Komponenten der Abgasnachbehandlung

Computer modeling as a complementary tool to experimental investigations is indispensable to design catalytic converters or diesel particulate filters. Therefore the present integrated 1D/3D workflow decisively accelerates the often very time consuming simulation process by combining the advantages of fast 1D and highly resolved 3D simulations. Characteristic parameters of design studies performed in Boost 1D aftertreatment are directly transferred to the 3D CFD code Fire and used for fine tuning.

Computer-aided optimisation of the exhaust gas aftertreatment system of the new BMW 1.8-litre valvetronic engine

The new BMW four-cylinder engine with Valvetronic has a unique market position with respect to performance, comfort, environmental compatibility and fuel efficiency. Within the scope of the development process of the new engine generation, numerical tools have significantly reduced the engineering time and the number of hardware components. This article presents the functional properties of the exhaust gas aftertreatment system and the support of the design process by computational methods.

Computergestützte Optimierung des Abgasnachbehandlungssystems für den neuen 1,8-l-Valvetronic-Motor von BMW

Die neuen BMW Vierzylindermotoren mit Valvetronic vereinen in herausragender Weise die Eigenschaften Dynamik, Komfort, Umweltvertraglichkeit und Wirtschaftlichkeit. Im Rahmen der Entwicklung der neuen Motorengeneration trugen Simulationswerkzeuge entscheidend dazu bei, den Produktentstehungsprozess zu verkurzen und den Hardware-Aufwand zu reduzieren. Der vorliegende Beitrag stellt die funktionalen Eigenschaften des Abgasnachbehandlungssytems und die Unterstutzung des Auslegungsprozesses durch computergestutzte Methoden vor.