Abstract
The purpose of this paper is to investigate the overall spray characteristics and combustion performance of palm oil methyl ester (PME). The overall spray characteristics include the spray tip penetration, spray cone angle, and atomization performance which obtained from the spray visualization system and KIVA-3v code. In order to analyze the combustion performance, the combustion pressure, the rate of heat release, and the indicated mean effective pressure of the direct injection single cylinder diesel engine are investigated. Investigation results of PME were compared to those of soy bean oil methyl ester (SME) and ultra low sulfur diesel (ULSD). Moreover, the fuel properties of PME, SME, and ULSD such as fuel density, kinematic viscosity, and surface tension, were studied, and the injection characteristics also investigated. It elucidated that the kinematic viscosity and surface tension of PME biodiesel fuel were higher than those of SME at 17◦ C, and the fuel density of PME is slightly lower than that of SME. All of fuel properties investigated in this work of ULSD is lower than both biodiesel fuels. The injection quantity of PME is somewhat lower than other fuels due to the high kinematic viscosity and low fuel density. The spray tip penetration of PME shows similar pattern and value compared to SME; however, it was slightly high at the time after the end of injection. In case of spray cone angle, PME showed the lowest value among test fuels. In addition, the high surface tension and kinematic viscosity had a bad influence on the droplet breakup of PME biodiesel fuel. On the other hand, the combustion performance included the IMEP of SME and PME shows almost similar pattern and characteristics. However, the exhaust emissions such as NOx, soot, HC, and CO of PME are superior to SME biodiesel fuel, as well as ULSD.
Keywords: Exhaust emissions, Palm oil methyl ester (PME), Sauter mean diameter (SMD), Soybean oil methyl ester (SME), Spray tip penetration