LAUSR

Abstract Reduction of environmental pollution and fossil fuel dependence are two worldwide concerned problems. Many research projects have addressed many solutions for these issues, in which, the trend of using bio-fuel has been widely studied and applied. Ethanol, a kind of biofuel has been used on motorcycle engines, which use carburetor system, to replace conventional gasoline. Ethanol is characterized by a higher heat of vaporization value than gasoline, thus the reduction of the intake manifold temperature which effects engine performance especially at cold starting and idling conditions. In this study, a certain amount of exhaust gas was recirculated to heat the intake manifold, thereby increasing intake mixture temperature, to improve the combustion process of the engine, results in improvement of engine performances. In experiment, an exhaust gas heating transfer system was designed to recirculate a partial mass of exhaust gas to transfer heat energy to the intake manifold of the test motorcycle fueled with ethanol. The experimental results show that, with the exhaust gas heating transfer system, the specific fuel consumption of the test engine improve remarkably and some gaseous emissions tend to be reduced; in addition, hot starting ability of the test engine with the heating transfer system improves significantly compared to the case of without the system.