Date of Award
Master of Science (MS)
John W. Daily
Improving vehicle efficiency is a substantial way to reduce CO2 emissions from the transportation sector. The most limiting factor of spark ignition (SI) gasoline engine efficiency is the phenomenon known as knocking. The current methods to characterize fuel knock resistance are with the Research Octane Number (RON) and Motor Octane Number (MON) methods. However, it has been shown that these engine-based test methods do not directly predict knock resistance in modern direct injection (DI) gasoline engines, especially under boosted conditions. Alternative test devices have been used to more directly study ignition kinetics. Constant volume combustion chambers (CVCCs) have been used to obtain valuable autoignition data at a broader ranger of pressure and temperature conditions than the single point engine operating conditions of the RON and MON tests. This study uses a new CVCC to study gasoline range fuels at engine relevant conditions to collect autoignition data on a set of simple gasoline surrogate fuels and correlate these data to the fuel chemistry and properties. A set of nine gasoline surrogates, with and without oxygenates were tested in the Advanced Fuel Ignition Delay Analyzer (AFIDA). The main outputs of this study are 3D surfaces of autoignition (ignition delay time) as a function of pressure and temperature. These data more completely characterize ignition delay at a wide range of engine relevant conditions, providing more insight than the RON and MON tests. Linear regression was performed between the ignition delay time and the fuel composition and properties, however significant correlations were not found. This study paves the way for more complex, full-boiling range gasoline fuels to be characterized in the AFIDA, fuels which are too complex to model with chemical kinetics.
Cameron, Drew Morales, "Autoignition Studies of Gasoline Surrogate Fuels in the Advanced Fuel Ignition Delay Analyzer" (2017). Mechanical Engineering Graduate Theses & Dissertations. 150.