SUMMARY
The objective of this study was to investigate the effects of castor biodiesel and its blends on the emission characteristics of a compression ignition engine. The research work was carried out on a single cylinder, four-stroke, water cooled, direct injection diesel engine by using biodiesel made from castor oil, compared with conventional diesel. The fuels used in the analyses are B5, B10, B15, B20, B25, B50, B100 and convectional diesel. The compression ignition engine was operated by varying the loading conditions (0 – 6kW) in a step of 1kW. Based on the parameters measured, detailed analyses were carried out on five regulated exhaust emissions i.e. NOX, CO, CO2, O2, and HC. The results clearly indicated that the engine running with biodiesel and their blends were reduced in CO, CO2 and HC emission by up to 20%. However, further reductions in emissions (CO, CO2, and HC) were observed as biodiesel concentration increases in the blends. Also for biodiesel and its blends, the NOX (10.6 – 37.7%) emissions increased with increase in the load and also, directly proportional to biodiesel concentration while O2 reduces as the load increases and increases as biodiesel concentration increased. The results from the experiments suggested castor biodiesel oil with the engine exhaust gases could be a good substitute fuel for existing diesel engine