Abstract. Biodiesel is the alternate fuel which is derived from renewable sources either is vegetable oils or animal fats. Biodiesel is non-toxic, have higher biodegradability, free of sulphur, no aromatics and its oxygen content of about 10-11% which is usually not contained in diesel fuel. These characteristics thus predominantly influences to the emissions of carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas. Purpose of this study is to investigate the effects of fuel additive, oil palm blended fuel, engine speed and test load conditions on the exhaust emissions and engine performance. The engine speed was varied from 1500 to 3000 rpm, load test condition varied by dynapack chassis dynamometer in 0, 50 and 100% and blends of 5(B5), 10(B10) and 15vol%(B15) palm oil with the diesel fuel. Increased of blends ratio with same mixing booster quantity can improve the engine performance, combustion process and give less CO emission. However, this condition tends to produce high NOx production due to higher oxygenated fuel in biodiesel content.
IntroductionBiodiesel which can offer the aspects as above is getting the higher attention from human being and the properties, performance and emissions of biodiesel have been further investigated. However, most biodiesel fuels have faced the problem where the fuels are not operating efficiently due to the variant in fuel properties. In diesel engine, the relation between mixture formation during the ignition delay period and burning process in diesel combustion that strongly affects the exhaust emissions [1][2][3][4][5]. Crude palm oil (CPO) has considerably biodegradable, higher viscosity and density compared to diesel fuel. The biodiesel also is renewable, non-toxic, less sculpture and aromatic contents. It can reduce the HC, CO, and PM which directly causes less greenhouse gas emissions. However the viscosity of fuels has important effects on the fuel droplet formation, atomization, vaporization and fuel-air-mixing process, which influencing the exhaust emissions and performance parameter of the engine [6][7][8][9]. In addition, higher viscosity will increase the fuel quantity, injection timing and spray pattern which influence the initial premixing and the combustion process. Hence, many researches show emissions concentrations (CO, CO 2 , PM, HC, O 2 and NOx) vary depending on the properties of biodiesel [10][11][12][13]. This research investigate the effects of booster racing formula, oil palm blended fuel, engine speed and test load conditions on the exhaust emissions and engine performance. It is expected that this work will provide the knowledge of the effects blending of booster properties and oxygenate fuel due to the variant in biodiesel blending ratio on combustion characteristics, emissions and performance.