Effect of Simulated-EGR (N2) on the distribution characteristics of equivalence ratio and the formation of exhaust emissions in a CI engine under early injection conditions

Optimization of simultaneous reduction of NO and soot by using simulated‐exhaust gas recirculation (CO2 + N2) in compression ignition engine under early combustion conditions

“…Validation results of exhaust emissions (P inj = 100 MPa, m inj = 14 mg, 1200 rpm) (The data that support the findings of this study are openly available in Journal of Energy at https://doi.org/10.1016/j.energy.2019.116850 17 ) [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…The numerical results were compared to verify with experimental results under the same conditions. Figure 4 shows the comparison results of cylinder pressure when the start of energizing timing was varied from BTDC 03 deg to BTDC 09 deg 17 . The symbols and lines mean the experimental results and the simulation results, respectively.…”

“…The experiment was conducted to verify the numerical analysis and Figure 1 shows the schematic of the experimental setup, which was referred to the previous study, 16 in this study. The experiment conditions and results were referred to the previous study 17 . So, only N 2 and O 2 gases were used in the experiment.…”

“…In order to express and investigate the effect of CO 2 mole fraction, the CO 2 mole fraction in the initial air composition by simulated‐EGR was varied from 0% to 20%. Furthermore, all conditions were operated under the same overall equivalence ratio of 0.68, which was adjusted by lowering the O 2 mole fraction from 21% to 16.2% in the initial air composition, and it was based on the previous study 17 . In this study, the generally used overall equivalence ratio equation was not matched due to the changed initial air composition in the cylinder by simulated‐EGR.…”

“…So, Pandey et al 15 have progressed a study under the early injection timing and various EGR rate conditions, and Cha et al 16 and have progressed an experimental study to simultaneously reduce the NO X and soot emission by using simulated‐EGR, which composed of N 2 gas under PCCI conditions. Min et al 17 have also conducted a numerical study to investigate the effect of simulated‐EGR (N 2 ) on the fuel mass fraction distributions and the formation/oxidation of exhaust emissions in CI engine. As a result, the injected fuel did not evaporate well and mix with air and formed liquid wall film, it occurred the reduction of NO emissions.…”