Effect of Methanol-Gasoline Blend and Ambient Pressure on Flame Propagation and Exhaust Emission of Spark Ignition (SI) Engine
To improve combustion efficiency of spark ignition (SI) engine, the laws of emission and growing demands for lower fuel consumption require significantly which satisfy the demand of emission quality. There are many technologies for reducing exhaust emissions of wide variety of spark ignition (SI) engine have been considered with the improvement throughout the combustion process. Alternative fuel such as methanol-gasoline blend were used due to the pros which is high in octane number and almost the same characteristic as gasoline that can give positive effect to the combustion process. The purpose of this study is to investigate the effects of methanol-gasoline fuel with different blend ratio and variant ambient pressure flame propagation and emissions of gasoline engine. In this study, an experiment towards flame propagation of methanol-gasoline fuel in a constant volume chamber were conducted. The image of combustion observe in the combustion chamber by using Schlieren optical visualization technique and analyzed by using image processing technique. The parameters in this research which include different blend ratio of methanol-gasoline fuel and also different ambient pressure of 0.10 MPa, 0.20 MPa and 0.30 MPa. As a result, due to the increasing in percentage of methanol content in gasoline, the combustion burn rate is increase. Thus, the higher flame propagation area for methanol-gasoline blend by M5, M10, M15 and M0 (RON 95) at the ambient pressure. The increasing in percentage of methanol content in methanol-gasoline fuel also reduce the emissions of CO, NOX and HC. However, the emission of CO2 increase due to improvement in combustion process.