@article{FrankenNetzerMaussetal., author = {Franken, Tim and Netzer, Corinna and Mauss, Fabian and Pasternak, Michal and Seidel, Lars and Borg, Anders and Lehtiniemi, Harry and Matrisciano, Andrea and Kulzer, Andre Casal}, title = {Multi-objective optimization of water injection in spark-ignition engines using the stochastic reactor model with tabulated chemistry}, publisher = {SAGE Publications}, address = {London, England}, issn = {1468-0874}, doi = {10.1177/1468087419857602}, abstract = {Water injection is investigated for turbocharged spark-ignition engines to reduce knock probability and enable higher engine efficiency. The novel approach of this work is the development of a simulation-based optimization process combining the advantages of detailed chemistry, the stochastic reactor model and genetic optimization to assess water injection. The fast running quasi-dimensional stochastic reactor model with tabulated chemistry accounts for water effects on laminar flame speed and combustion chemistry. The stochastic reactor model is coupled with the Non-dominated Sorting Genetic Algorithm to find an optimum set of operating conditions for high engine efficiency. Subsequently, the feasibility of the simulation-based optimization process is tested for a three-dimensional computational fluid dynamic numerical test case. The newly proposed optimization method predicts a trade-off between fuel efficiency and low knock probability, which highlights the present target conflict for spark-ignition engine development. Overall, the optimization shows that water injection is beneficial to decrease fuel consumption and knock probability at the same time. The application of the fast running quasi-dimensional stochastic reactor model allows to run large optimization problems with low computational costs. The incorporation with the Non-dominated Sorting Genetic Algorithm shows a well-performing multi-objective optimization and an optimized set of engine operating parameters with water injection and high compression ratio is found.}, subject = {Ottomotor; Water injection; Genetic optimization; Spark-ignition engine; Stochastic reactor model; Detailed chemistry; Wassereinspritzung; Prozessoptimierung; Stochastisches Modell}, language = {en} } @phdthesis{Seidel2017, author = {Seidel, Lars}, title = {Development and reduction of a multicomponent reference fuel for gasoline}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-42696}, school = {BTU Cottbus - Senftenberg}, year = {2017}, abstract = {Within this thesis, a detailed multicomponent gasoline surrogate reaction scheme was developed and reduced to a four component scheme of skeletal size. The main target is to cover the most important features for typical spark ignited (SI) combustion - flame propagation, emission formation and the tendency to auto ignite and subsequently cause engine knock. To achieve this a variable mechanism concept was developed to include sub models for different fuels as needed. Using this approach a detailed mechanism describing the oxidation of n-heptane, iso-octane, toluene and ethanol was compiled and compared against various experiments published in literature. Furthermore, correlations were developed to suggest four component gasoline surrogates based on typical fuel data sheets. The correlation method is validated against measurements in Cooperative Fuel Research (CFR) engine from various groups and further compared against correlations between octane numbers (ON) and predicted 0D ignition delay times. These correlations are used to identify and discuss the impact of the uncertainty of two reactions on ignition delay time of a multicomponent fuel. To be able to reduce the detailed scheme in a time efficient way existing reduction concepts where improved and applied to different schemes and targets. Since various reduction techniques are available, an optimal sequence of those was worked out. Using this sequence of reduction steps two multicomponent schemes were compiled: one scheme for the prediction of laminar flame speeds and one for the prediction of major emissions and auto-ignition. To underline that the suggested reduction procedure is universal it was also applied to n-heptane as single fuel surrogate for diesel fuel and to a large two component fuel from another work group.}, subject = {Mechanism reduction; Surrogate fuels; Gasoline; Combustion modelling; Reaction mechanism; Verbrennungsmodellierung; Benzin; Mechanismen Reduktion; Reaktionsmechanismus; Referenz Kraftstoffe; Benzin; Verbrennung; Reaktionsmechanismus}, language = {en} }