Flame Propagation of Bio-Ethanol in a Constant Volume Combustion Chamber

This research presents an experimental study of the combustion of ethanol blends with gasoline in a constant volume combustion chamber. The test fuels are gasoline, E20 (ethanol20%), E85 (ethanol85%) and pure ethanol. The pressure in combustion chamber was measured. The images of flame propagation were recorded by schlieren technique with high speed video camera. The effects of equivalent ratio, temperature, pressure on the combustion characteristics were studied. The results show the greater percent of ethanol provides faster burn rate of combustion and higher peak of cylinder pressure. The peak combustion pressure E100 is 0.873 MPa which is higher than E85, E20 and E0. The ignition delay time decreases with higher percent of ethanol. As the results of flame propagation images, at stoichometric burn duration of pure ethanol is 13 ms which is shorter than E85, E20 and E0. The combustion duration of mixture at equivalence ratio of 1.0 is less than that of equivalent ratio 0.8, 1.2 and 1.4. The flame speed and peak pressure increase with percentage of ethanol. The faster flame speed of ethanol flame effects to shorter combustion duration and greater performance and efficiency.