Summary: | 碩士 === 南開科技大學 === 車輛與機電產業研究所 === 99 === In recent years, the greenhouse effect and environmental protection is concerned for all people. Therefore the research to reduce pollutant emissions is still progressing. In Taiwan, transportation is one of majority of pollutant emission sources, especially, the emissions from motorcycles. In the study of reduction of pollutant emissions, except for modifying engine design, the most of research is focused on alternative fuels and after-treatment exhaust gas. In this study, secondary air injection system and 10%, 15% and 20% ethanol- blended gasoline fuels mixed with 95 unleaded petrol and ethanol are explored to observe the effect of engine performance and exhaust emissions.
Experimental results show that, at 50% throttle opening, the engine output performance will be a little lower for the blended fuel, compared with pure gasoline. On the other hand, due to the relatively oxygen-rich characteristics of ethanol, the air-fuel ratio λ tends to or is greater than 1. It reduces CO and HC emissions, and makes NO and CO2 emissions increased. If the λ is controlled as 1, CO and HC emissions are higher than original ECU, but NO and CO2 emissions are lower than original ECU. For the affection of the secondary air injection system, more secondary air flow rate does not apparently improve the effects of CO well compared with ethanol-gasoline blended fuels, but for HC the emission decreases while the secondary air flow rate increases, NO is reduced for low percentage of ethanol-gasoline blended fuels (E0 and E10). CO2 is improved for secondary air flow rate (8, L/min and 10 L/min).
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