@misc{FrankenMaussSeideletal., author = {Franken, Tim and Mauß, Fabian and Seidel, Lars and Gern, Maike Sophie and Kauf, Malte and Matrisciano, Andrea and Kulzer, Andre Casal}, title = {Gasoline engine performance simulation of water injection and low-pressure exhaust gas recirculation using tabulated chemistry}, series = {International Journal of Engine Research}, volume = {21}, journal = {International Journal of Engine Research}, number = {10}, issn = {2041-3149}, doi = {10.1177/1468087420933124}, pages = {1857 -- 1877}, abstract = {This work presents the assessment of direct water injection in spark-ignition engines using single cylinder experiments and tabulated chemistry-based simulations. In addition, direct water injection is compared with cooled low-pressure exhaust gas recirculation at full load operation. The analysis of the two knock suppressing and exhaust gas cooling methods is performed using the quasi-dimensional stochastic reactor model with a novel dual fuel tabulated chemistry model. To evaluate the characteristics of the autoignition in the end gas, the detonation diagram developed by Bradley and coworkers is applied. The single cylinder experiments with direct water injection outline the decreasing carbon monoxide emissions with increasing water content, while the nitrogen oxide emissions indicate only a minor decrease. The simulation results show that the engine can be operated at l = 1 at full load using water-fuel ratios of up to 60\% or cooled low-pressure exhaust gas recirculation rates of up to 30\%. Both technologies enable the reduction of the knock probability and the decrease in the catalyst inlet temperature to protect the aftertreatment system components. The strongest exhaust temperature reduction is found with cooled low-pressure exhaust gas recirculation. With stoichiometric air-fuel ratio and water injection, the indicated efficiency is improved to 40\% and the carbon monoxide emissions are reduced. The nitrogen oxide concentrations are increased compared to the fuel-rich base operating conditions and the nitrogen oxide emissions decrease with higher water content. With stoichiometric air-fuel ratio and exhaust gas recirculation, the indicated efficiency is improved to 43\% and the carbon monoxide emissions are decreased. Increasing the exhaust gas recirculation rate to 30\% drops the nitrogen oxide emissions below the concentrations of the fuel-rich base operating conditions.}, language = {en} } @misc{FrankenSrivastavaLeeetal., author = {Franken, Tim and Srivastava, Vivek and Lee, Sung-Yong and Heuser, Benedikt and Shrestha, Krishna Prasad and Seidel, Lars and Mauß, Fabian}, title = {Numerical Analysis of the Combustion of Diesel, Dimethyl Ether, and Polyoxymethylene Dimethyl Ethers (OMEn, n=1-3) Using Detailed Chemistry}, series = {THIESEL 2022 : Conference on Thermo- and Fluid-Dynamics of Clean Propulsion Powerplants, 13th-16th September 2022 : conference proceedings}, journal = {THIESEL 2022 : Conference on Thermo- and Fluid-Dynamics of Clean Propulsion Powerplants, 13th-16th September 2022 : conference proceedings}, editor = {Xandra, Margot and Payri, Ra{\´u}l and Serrano, Jos{\´e} Ram{\´o}n}, publisher = {Editorial Universitat Polit{\`e}cnica de Val{\`e}ncia}, address = {Val{\`e}ncia}, isbn = {978-84-1396-055-5}, doi = {10.4995/Thiesel.2022.632801}, abstract = {New types of synthetic fuels are introduced in internal combustion engine applications to achieve carbon-neutral and ultra-low emission combustion. Dimethyl Ether (DME) and Polyoxymethylene Dimethyl Ethers (OMEn) belong to such kind of synthetic fuels. Recently, Shrestha et al. (2022) have developed a novel detailed chemistry model for OMEn (n=1-3) to predict the ignition delay time, laminar flame speed and species formation for various thermodynamic conditions. The detailed chemistry model is applied in the zero dimensional (0D) stochastic reactor model (DI-SRM) to investigate the non-premixed combustion in a 2-liter diesel engine. Further insights in the formation of unburned hydrocarbons (HC), carbon monoxide and nitrogen oxides during the combustion of OMEn fuels are obtained in this work. The combustion and emission formation of DME and OMEn (n=1-3) are investigated and compared to conventional Diesel combustion. The mixture formation is governed by an earlier vaporization of the DME and OMEn fuels, faster homogenization of the respective air-fuel mixture and higher reactivity. At the same injection pressure, the OMEn fuels obtain higher NOx but lower CO and HC emissions. High amounts of aromatics, ethene, methane formaldehyde and formic acid are found within the Diesel exhaust gas. The DME and OMEn exhaust gas contains higher fractions of formaldehyde and formic acid, and fractions of methane, methyl formate and nitromethane.}, language = {en} }