Biodiesel Blends Startability and Emissions During Cold, Warm and Hot Conditions

Abstract

The time and emissions during cold starting were investigated at cold and hot temperatures (i. e., – 10°C, 0 °C, 25°C and 50 °C). The effect of injection timing (IT) on these factors was also studied at four ITs before top dead centre (BTDC) i. e., (12 , 15 , 20 and 23 BTDC). The results were compared with engine operation at 17 BTDC (factory IT). Sunflower vegetable oil and yellow grease were used as raw materials to prepare bio diesel fuels through transesterification. B20 (20% sunflower oil biodiesel+80% diesel) and W20 (20% yellow grease biodiesel+80% diesel), together with neat conventional Iraqi diesel fuel, were used to analyse engine startability and emissions under cold and hot starting conditions. Results indicated that adding biofuel affects the engine starting response and that the starting time stabilises at high starting temperatures. At a low starting temperature (i. e.,–10 °C), hydrocarbon (HC) and carbon monoxide (CO) concentrations increase significantly. At moderate and high starting temperatures, the oxygen content in the biofuel blend plays a dominant role in reducing the HC and CO concentrations. Smoke opacity has increased notably for the biodiesel blends at low starting temperatures but has decreased significantly at moderate and high starting temperatures. Both biofuel blends emit higher levels of nitrogen oxide than the neat diesel fuel. Noise increases at low starting temperatures, thereby indicating rough combustion.