Engine Performance and Emission Characteristics of Gasoline-Methanol Blends with Power Interruption Observations

Methanol, as a renewable and environmentally friendly fuel, can be utilized directly or blended with gasoline in spark-ignition engines. Blending methanol with gasoline has been investigated as a means to enhance engine performance and reduce exhaust emissions, with previous studies reporting improvements in octane number and certain performance parameters. However, the findings remain inconsistent, requiring further study. This research examines the effects of gasoline–methanol blends (10%, 15%, 20%, and 25% by volume) on engine performance and exhaust emissions. For comparison, gasoline with research octane numbers (RON) of 92 and 98 was also tested. Performance measurements were conducted using a dynamometer, while exhaust emissions were evaluated with a gas analyzer. A carburetor engine with factory-set air–fuel ratio was employed, and a four-hour continuous performance test was performed to assess long-term effects. The results indicate that higher methanol content increased power and torque, while reducing brake-specific fuel consumption (BSFC). Emission analysis showed reductions in carbon monoxide (CO) and total hydrocarbons (THC), alongside increased carbon dioxide (CO2). The continuous test revealed occasional engine power interruptions, which occurred more frequently at higher methanol concentrations.