Study on the Ignition Delay Time of n-Heptane Fuels

As a basic standard for gasoline anti-knock performance, the ignition delay time (IDT) of n-hexane is essential for optimizing internal combustion engine efficiency and lowering pollutants. IDT is an essential metric in combustion research because it represents the reactivity of fuels under different thermodynamic circumstances and offers critical benchmarks for confirming chemical kinetic models. This study investigated n-heptane IDT using experimental approaches (shock tube, rapid compression machine (RCM), spherical bomb) and kinetic modeling (Currans detailed mechanism, Peters skeletal models). By combining laboratory-scale measurements with numerical simulations, the study establishes a more comprehensive picture of ignition behavior. Effects of fuel blending (H, n-butanol), EGR dilution, and surrogate fuels are examined. Key findings include: H prolongs IDT by ~27% in the NTC region; n-butanol affects IDT through OH radical competition; a ternary surrogate (63% iso-octane/20% toluene/17% n-heptane) replicates gasoline IDT within 10%. Data for < 600 K or > 30% EGR are limited, cross-reactions are frequently disregarded, and simplified processes differ in NTC-region predictions. All things considered, this work supported international initiatives to lower emissions associated with combustion and enhance engine design techniques by strengthening the connection between experimental combustion research and kinetic modeling and offering insights for the production of cleaner fuels.