Abstract
In this study, the combustion characteristics and emissions of compression ignition diesel engine were measured using a biodiesel as an alternative fuel. The tests were performed in Chemical and Mechanical Engineering department laboratories at steady state conditions for a four stroke single cylinder diesel engine loaded at variable engine speed between 1200-2600rpm. The waste vegetable oil (cocking oil) used in this investigation transferred from Tafila Technical University restaurant collected and disposed in a suitable way. The testing results show without any modification to diesel engine, under all conditions dynamical performance kept normal, and the B20, B5 blend fuels (include 20%, 5% biodiesel respectively) led to satisfactory emissions at variable load. The experimental results compared with standard diesel show that biodiesel provided significant reductions in CO, and unburned HC, but the NOx was increased. Biodiesel has a 5.95% increasing in brake-specific fuel consumption due to its lower heating value. However, using B20 and B5 diesel fuel gave better emission results, NOx and brake-specific fuel consumption.
The experimental results show that the fuel consumption rate, brake thermal efficiency, and exhaust gas temperature increased while the bsfc, emission indices of CO2, CO decreased with an increase of engine speed. Moreover, the engine power increased when increasing the biodiesel percentage varied from 1.23 to 3.2 for standard diesel while for B20 between 1.5 to 3.47.while brake specific energy consumption varied between 16.8 to 13.81MJ/kW.kg for standard diesel, but for B5 found to be between 16.3 to 13MJ/kW.kg. In particular, biodiesel produced with the addition of the peroxidation process had the lowest equivalence ratio and emission indices of CO2, CO. The emission of NOx among all of the test fuels found to be increased when using B5 and B20 instead of standard diesel and these results validate the data recorded by other previous work. Therefore, the peroxidation process can be used effectively to improve the fuel properties and reduce emissions when biodiesel is used.