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Blends of up to 40% by volume methanol in a methanol-gasoline fuel blend were supplied to a single cylinder engine operating under controlled conditions. The following effects are reported as the methanol concentration increases. The lean misfire limit is extended 0.04 Ø by using a blend containing 40% methanol compared to the base fuel. It is also noted that the lean misfire limit does not vary until a blend containing greater than 20% methanol was used. Torque and thermal efficiency increase significantly. Percent by volume concentrations of carbon monoxide, carbon dioxide and oxides of nitrogen do not change, although oxides of nitrogen reported as mass per power output per hour decrease.

A single cylinder engine was operated in HCCI mode with diesel-range fuels, spanning a range in cetane number (CN) from 34 to 62. In addition to measurements of standard gaseous emissions (CO, HC, and NOx), multiple sampling and analysis techniques were used to identify and measure the individual exhaust HC species including an array of oxygenated compounds. A new analytical method, using liquid chromatography (LC) with electrospray ionization-mass spectrometry (ESI-MS) in tandem with ultraviolet (UV) detection, was developed to analyze the longer chain aldehydes as well as carboxylic acids. Results showed an abundance of formic and butyric acid formation at or near the same concentration levels as formaldehyde and other aldehydes.