Influence of Ethanol-gasoline Blended Fuels on Cold Start Emissions of a Four-stroke Motorcycle. Methodology and Results

The aim of this study is to investigate the effect of ethanol-gasoline mixtures on cold emissive behavior of commercial motorcycles. For the newly sold motorcycles, equipped with a three-way catalyst and electronic mixture control, CO and HC cold additional emissions, if compared with those exhausted in hot conditions, represent an important proportion of total emissions. On the other hand, ethanol is known as potential alcohol alternative fuel for spark ignition engines, which can be blended with gasoline to increase oxygen content and then to decrease emissions. From this explanations, a research on cold start emissions of motorcycles using ethanol-gasoline mixtures was conducted. In this specific study, a motorcycle (belonging to the Euro-3 legislative category) was operated on a chassis dynamometer and driven according to the ECE driving cycle to analyze the exhaust cold extra emissions of CO and HC, while the ethanol was mixed with unleaded gasoline in three different percentages (10, 20 and 30 % v/v). Results of the tests and the application of a calculation procedure, designed to model the cold start transient behavior of motorcycles, indicate that CO and HC cold start extra emissions using ethanol-gasoline blended fuels decrease compared to the use of unleaded gasoline.