Experimental Investigation of Diesel Engine Performance and Emission Characteristics Fuelled by Jojoba/Diesel Blend and Sunflower Oil

Experimental study has been carried out to investigate performance parameters, emissions, cylinder pressure, exhaust and wall temperatures at different engine speeds and different percentage of EGR using sunflower and jojoba/diesel (B20) blend in comparison to diesel fuel. Sunflower oil and B20 were selected for the study because of its being widely used in Egypt and world. Tests were conducted for three different fuels with different engine speeds. Also, series of tests were conducted at same previous conditions with different percentage of exhaust gas recirculation (EGR) rates from 0 to 12% of inlet mass of air fresh charge. Results indicate that sunflower or B20 blend gives lower brake thermal efficiency, brake power, brake mean effective pressure, and higher BSFC due to lower heating value compared to diesel fuel. Sunflower or B20 blend gives lower NO_X concentration due to lower gases temperature. Sunflower or B20 blend gives higher wall/exhaust temperatures due to incomplete combustion inside engine cylinder. Sunflower or B20 blend gives higher CO and CO₂ concentrations due to higher carbon/hydrogen ratio. The position of maximum pressure change for diesel fuel is earlier than for sunflower and B20 blend. The results show that sunflower and B20 blend are promising as alternatives fuel for diesel engine. One of the main advantages of vegetable oil is not requiring significant modification of existing engine hard wares. On contrast, the main disadvantages of biodiesel fuels are high viscosity, drying with time, thickening in cold conditions, flow and atomization characteristics.