The Use of E100 to Fuel a Used 4-Stroke Motorcycle

Abstract

Problem statement: Though ethanol and gasohol are proved to be used as alternative fuels in vehicles, 4-stoke motorcycles used nationwide mainly consumed gasoline 91/95. Approach: The motorcycle tested, the used Honda Wave125 model, was properly tuned at the rich relative air-fuel ratio (λ) 0.85, which theoretically gave the maximum power output. For the use of E100, the engine required richer air-fuel mixture condition, the main nozzle and idle nozzle sizes were therefore increased from the sizes used for gasoline91; by 21.4% from 0.78 mm for the main nozzle and 76% from 0.35 mm for the idle nozzle. Due to having three times higher in heat of vaporization, the stronger current ignition coil was used instead. This eased the engine starting without any trace amount of gasoline. The ignition timing was advanced by about +9^Ocrank angle to suit E100’s high octane number of 107. Results: The performance test results of E100 on dynamometer showed that the maximum power output was 9 hp@7428 rpm and the maximum torque was 11 Nm@4728 rpm. Comparing to the use of gasoline91, the engine performance decreased 12-15% over the speed range of around 4000-8000 rpm. From the road tests; city road test and long driving test, at the average speed of 60 km h^-1 the average consumption rate of E100 was about 25-28% more. The calculated fuel conversion efficiency of E100 was 38.2% higher. For emission measurements when using E100, the concentrations of CO and of HC were 3.14 vol % and 2143 ppm. Those were higher than in the exhaust of the use of gasoline91 but below the regulations which required <4.5vol % for CO concentration and <10,000 ppm for HC concentration. Though the NOx concentration in the exhaust of all tests was not measured, high NOx concentration was observed in the lean mixture at λ >1.0 condition. Since a particular instrument was not available, aldehyde concentration in the E100’s emission was not measured. Conclusion: It clearly confirmed that E100, 95.5 vol % ethanol, can be effectively used as an alternative fuel in used 4-stroke motorcycles whose carburetors were purposely designed for the use of gasoline91. If the engines were properly tuned up and modified to best suit the E100’s characteristics while maintaining the compression ratio, the motorcycles performed as efficient as fueling gasoline91.