The
ignition delay for pure cyclohexane and two quaternary gasoline
surrogate fuels CTRF1 (isooctane/n-heptane/toluene/cyclohexane,
37.070/11/40.076/11.854 by mole fraction), CTRF2 (isooctane/n-heptane/toluene/cyclohexane, 30.538/11/43.077/15.385 by
mole fraction) with the same research octane number of 95 (RON = 95)
in air is measured under lean, stoichiometric, and rich conditions
behind reflected shock waves, at temperatures of 1027 K–1400
K, and pressures of 10, 15, and 19 bar/20 bar. To analyze the effects
of exhaust gas recirculation upon ignition, CTRF1/air mixtures are
diluted with CO2 to simulate different exhaust gas recirculation
(EGR) loadings (0, 20%, 40%, and 60%). The experimental data are compared
to the predictions calculated by a detailed chemical kinetic mechanism
with 526 species and 2763 reactions generated in this work, which
is also validated by the autoignition characteristics of pure cyclohexane,
iso-octane, n-heptane, toluene, and their binary
and ternary mixtures. The simulation results of the mechanism are
in good agreement with the experimental measurements, and both the
experimental and kinetic modeling data illustrate a negative correlation
between the ignition delay of CTRF1/CTRF2 and the pressure, temperature,
and equivalence ratio, and a clear rise of the ignition delay for
CTRF1 with increased EGR loadings is also showed. Moreover, on the
basis of the detailed kinetic model, the reaction pathway, rate of
production analysis, and sensitivity analysis are also performed to
clarify the influence of EGR on the ignition delay of CTRF1, which
indicates the predominate role of thermal and dilution effects that
CO2 has on the ignition, while the chemical effects are
proven negligible over the range of experimental conditions.