Comparative Study on the Effects of Gasoline-Ethanol Blends for Performance and Emissions Characteristics In-Use Motorcycle SI Engine

To investigate the feasibility of using bioethanol as a potential fuel on engines, an experimental comparative study on aspects of the performance and emission characteristics was carried out on the in-use motorcycle SI engine type Wave RSX 110cc. Five tested fuels consisting of ethanol (E100), reference gasoline RON 95 (E0), and blends of ethanol and gasoline in many mixing ratios of 25% (E25), 50% (E50), 85% (E85) were taken under different engine speeds in the range from 3000 to 8000 rpm at a constant opening of 70% throttle. A method for adjusting the appropriate amount of the injected fuel was applied via injection duration and fuel pressure by the tuning electronic control system. The results revealed that brake-specific fuel consumption (BSFC) increased on average by 26.4%, 43.45%, 71.14%, and 104.27% corresponding to E25, E50, E85, and E100, respectively, compared to E0. A decreasing trend in engine torque and power within 12.5% has been noted with an increase in ethanol blending percentages and engine speeds. One prominent tendency of emission reduction such as CO, CO2, HC, and NOx was observed when increasing the ethanol blending ratio while the CO2 and NOx emissions showed rising concentration at higher engine speeds. On the other hand, CO and HC emissions displayed the opposite trend. In general, E25 shows the engine stability performance under experimental conditions.