Octane Response of Gasoline Fuels to Different Antiknock Oxygenates Addition

Abstract

A series of renewable and clean oxygenated compounds possessing high octane numbers, including alcohols, ethers, esters, and furans, were used as octane boosters for gasoline fuels, and the octane responses of the gasoline fuels to these oxygenates addition were evaluated. Gasoline model fuels of different typical hydrocarbon compounds, including iso-octane, n-heptane, toluene, diisobutylene, and cyclohexane, were designed to have the identical octane rating. The research octane number (RON) and motor octane number (MON) of the gasoline model fuels with antiknock oxygenates addition were experimentally measured on a standard cooperative fuel research (CFR) engine. The results highlight the varied impact of antiknock oxygenates on the octane enhancement of gasoline fuels, with 2-methylfuran exhibiting the most pronounced RON boost effect and ethanol demonstrating the strongest MON enhancement effects, and isopropyl ether and dimethyl carbonate show the weakest RON and MON boost effects, respectively. The antiknock enhancement effects of the oxygenated additives are dependent on gasoline fuel compositions. With the antiknock oxygenates addition, primary reference fuel (PRF) model fuel shows more significant octane enhancements, and the octane boosting effects are reduced for the gasoline model fuels containing toluene or diisobutylene, indicating an antagonistic interaction between the oxygenates and toluene/diisobutylene. By comparing the octane enhancement effects of the tested antiknock additives, it is evident that 2-methylfuran and ethanol are the more superior antiknock candidates for gasoline fuels.