Abnormal Combustion in Methanol-Fueled, Crankcase-Scavenged Two-Stroke Engines - A Theoretical Study

Two Computer models were used to study abnormal combustion in a crankcase-scavenged two-stroke engine fueled on methanol. Experimental studies had shown that the octane rating of methanol in this engine was lower than that of gasoline when compared to known reference fuels. Through computer modeling, the abnormal combustion was shown to be a combination of auto and surface ignition resulting from high intake charge temperatures and high residual fractions inherent in crankcase-scavenged two-stroke engines. Precursors of knock were also shown.