Assessment of Binary and Ternary Biofuel Mixtures on the Performance and Emissions of a Common-rail Diesel Engine

Biofuels used as additives for Diesel engine are proposed to diversify fuel sources and reduce greenhouse gas (GHG) emissions, but also to optimize engine performance, as well as to reduce pollutant emissions. In addition, when these biofuels are produced from low-grade wastes, they consume their energy and solve an environmental problem which is the disposal of hazardous wastes. In this study, pyro-diesel (obtained from the pyrolysis of low-grade bio-oils wastes), biodiesel and ethanol were evaluated as additives for diesel, in a series of tests performed on a common-rail Diesel engine. Binary fuel mixtures of pyro-diesel+diesel, biodiesel+diesel and ethanol+diesel with biofuel incorporation between 5% (w/w) and 10% (w/w) were evaluated and compared with ternary fuel mixtures of pyro-diesel+ethanol+diesel and biodiesel+ethanol+diesel with biofuel incorporation of 5% (w/w). The fuel mix performance was assessed by determination of brake torque and power, fuel consumption and efficiency, as well as engine emissions (HC, NOx, and smoke). Part-load torque (50 and 70 N.m and wide-open throttle-WOT) with constant 0.5 bar turbocharging pressure were tested at two different engine speeds (1800 and 2250 rpm). The additives incorporation up to 10% tended to improve combustion efficiency and reduce emissions such as HC, NOx, and opacity relatively to straight diesel.