Performance, combustion, and emissions characteristics of a single-cylinder compression ignition engine operated on ethanol-biodiesel blended fuels

摘要

Fossil fuels such as oil, gas, and coal have driven the world's economies since the industrial revolution and have released carbon emissions in the process. About 26 billion tons of carbon dioxide are produced every year and this is still increasing. The 1997 Kyoto agreement is the world's only attempt to regulate carbon emissions. Diesel engines have been widely used as the major propulsion power sources because of their simple, robust construction coupled with high thermal efficiency and specific power output with high fuel economy. However, diesel engines are the major contributors of various types of air pollutants such as carbon monoxide (CO), oxides of nitrogen (NO_x), particulate matter (PM), and other harmful compounds. The reduction in engine emissions is a major research objective in the engine development because of increasing concern for the environment pollution and more stringent government regulation on exhaust emissions. It is difficult to reduce PM and NO_x simultaneously owing to the tradeoff between PM and NO_x [1]. Ethanol is a renewable energy and can be made from many raw materials such as sugarcane, molasses, waste biomass materials, corn, sugar beets, and so on by using already improved and demonstrated technologies [2, 3]. The objective of the present work is mainly concerned with determination of maximum possible and optimum replacement of diesel by biodiesel-ethanol blends and comparing the performance of diesel engines fuelled with these fuel combinations. The effects of different ethanol-biodiesel blended fuels on the performance, combustion, and emission characteristics of compression ignition engines have been evaluated experimentally and compared in this article. The optimum percentage of ethanol that gives simultaneously better performance and lower emissions when blended with both biodiesel is determined. The experiments were conducted on a water-cooled single-cylinder direct injection (DI) diesel engine using 0 per cent, 5 per cent, 10 per cent, and 15 per cent biodiesel of honge and jatropha oils-ethanol blends. For the same rated power, different blended fuels as well as pure diesel and biodiesel fuels, various engine parameters such as power, torque, fuel consumption, and exhaust temperature, combustion parameters such as heat release rate, ignition delay, combustion duration, and exhaust emissions such as smoke opacity, hydrocarbon, CO, and NO_x, were measured. The results indicate that the brake thermal efficiency increased with an increase in ethanol contents in the blended fuels at overall operating conditions. Smoke emissions decreased with increased ethanol-biodiesel blended fuels and NO_x emissions increased. Total hydrocarbon emission (THC) also decreased significantly when compared to neat diesel and biodiesel fuel operations.