An experimental and modeling study of autoignition characteristics of two real low-octane gasoline fuels in a heated rapid compression machine at elevated pressures

摘要: Abstract Gasoline compression ignition (GCI) has received much attention due to its high efficiency and low emissions. The low-octane gasoline can be applied extend the GCI operating range. However, there is limited knowledge of autoignition chemistry for gasoline. In this study, delay times (IDTs) two real distillate fuels with research octane numbers (RON) 72 83, denoted as G72 G83 respectively, were measured in a heated rapid machine (RCM) over wide ranges pressures (10, 15 20 bar), temperatures (670–940 K), equivalence ratios (0.5, 1.0 2.0), diluted conditions. Both exhibit apparent two-stage characteristics negative temperature coefficient (NTC) behavior low-to-intermediate region. Considering effects exhaust gas recirculation (EGR) technology on combustion, gasolines under simulated-EGR conditions also studied by varying N2/O2 ratio while fixing fuel mole fraction. It found that NTC region moves towards higher side oxygen concentration decreases. Moreover, six-component surrogates formulated (28.4% n-pentane, 3.5% n-heptane, 24.5% 2-methylhexane, 26.3% 2,2,4-trimethylpentane, 13.8% cyclopentane, 3.3% toluene, mol.), (16.5% 10.6% 5.6% 37.4% 10.2% cyclopentane 19.7% mol.). Kinetic modeling was then conducted using published kinetic model coupled proposed surrogates. Sensitivity analysis results further revealed compared isooctane, cycloalkane more important overall at temperatures.