Technical Paper
The Reactivity Behavior of n-Heptane and Isooctane Blends in a Motored Knock Research Engine
1992-02-01
920807
This paper presents results of studies investigating the reactivity of primary reference fuel blends in a motored research engine. Reactivity was quantified by measuring exhaust manifold carbon monoxide concentration [CO], cylinder pressure histories, and in-cylinder gas composition. The fuels used were n-heptane (0 PRF), isooctane (100 PRF), and blends of the two with octane values of 0, 25, 55, 63, 75, 87, and 100. A supercharged single-cylinder engine was motored at a constant engine speed and constant inlet pressure as the inlet gas temperature was increased by manifold heating until either the fuel/air mixture autoignited or the maximum temperature of the facility (490 K) was reached. In-cylinder gas samples were obtained and analyzed by gas chromatography for overall fuel reactivity and for the concentrations of light hydrocarbon (
