Abstract
To investigate the effect of exhaust gas recirculation (EGR) on ignition characteristics of gasoline surrogate, ignition delay times of gasoline surrogate mixtures, S5H, consisting of n-heptane, isooctane, toluene, diisobutylene, and methylcyclohexane were measured using a rapid compression machine under the EGR conditions at the pressure of 2 MPa and 4 MPa, at 720 K, and an equivalence ratio of 0.5. Ignition delay times were also calculated using a detailed chemical kinetic model of gasoline surrogate mixtures. Ignition delay times of S5H under the EGR condition were longer than those of S5H without EGR gas. The most contributory factor under the EGR conditions was investigated using the experimental and calculated results. As a result, it is found that the reduction of fuel concentration in the initial gas mixtures had the strongest influence on the ignition characteristics of gasoline surrogate among the various factors under the EGR conditions.
