Investigation of auto-ignition characteristics of blended gasoline with a variety of hydrocarbons with different molecular structures

Abstract

In this study, the ignition delay time of gasoline blended with various hydrocarbons having different molecular structures (isooctane, n-heptane, 1-pentene, and toluene) was measured using a rapid compression machine. Additionally, the effect of mixing hydrocarbons on the ignition characteristics of gasoline surrogate fuels was investigated. The ignition delay times were measured under two conditions: an equivalence ratio of 0.5 and an equivalence ratio of 1.0 with an EGR ratio of 30%. The compressed pressure and temperature were 4.0 MPa and 750 K, respectively. When toluene was blended with the gasoline surrogate, the ignition delay time increased regardless of the experimental conditions. In contrast, when n-heptane was blended with the gasoline surrogate, the ignition delay time decreased. When isooctane and 1-pentene were individually blended with the gasoline surrogate, the ignition delay times were unchanged with varying mixing ratios. Based on the chemical kinetic analysis, it is found that the reactivity for the low-temperature oxidation of blended fuels changed when each hydrocarbon was blended, which determines the ignition characteristics of blended fuels.