Experimental work was done to examine the impact of diesel fuel with alumina nanoparticles on combustion characteristics, emissions and performance of diesel engine. Alumina nanoparticles were mixed with crude diesel in various weight fractions of 20, 30, and 40 mg/L. The engine tests showed that nano alumina addition of 40 ppm to pure diesel led to thermal efficiency enhancement up to 5.5% related to the pure diesel fuel. The average specific fuel consumption decrease about neat diesel fuel was found to be 3.5%, 4.5%, and 5.5% at dosing levels of 20, 30, and 40 ppm, respectively at full load. Emissions of smoke, HC, CO, and NO_X were found to get diminished by about 17%, 25%, 30%, and 33%, respectively with 40 ppm nano-additive about diesel operation. The smaller size of nanoparticles produce fuel stability enhancement and prevents the fuel atomization problems and the clogging in fuel injectors. The increase of alumina nanoparticle percentage in diesel fuel produced the increases in cylinder pressure, cylinder temperature, heat release rate but the decreases in ignition delay and combustion duration were shown. The concentration of 40 ppm alumina nanoparticle is recommended for achieving the optimum improvements in the engine’s combustion, performance and emission characteristics.

This paper first describes a slow catalytic pyrolysis process used for synthesizing biodiesel from waste cooking oil (WCO) as a feedstock. The influence of variations in the catalyst type (sodium hydroxide and potassium hydroxide), and catalyst concentration (0.5, 1.0, 3.0, 5.0, 7.0 and 10.0% by weight) on both the pyrolysis temperature range and biodiesel yield were investigated. The results suggested that sodium hydroxide (NaOH) was more effective than potassium hydroxide (KOH) as catalysts and that the highest yield (around 70 wt.%) was observed for a NaOH concentration of about 1 wt.% The resultant pyrolysis temperature range was also significantly lower for NaOH catalyst, thus suggesting overall lower energy consumption. Compared to conventional diesel, the synthesized biodiesel exhibited relatively similar physical properties and calorific value. The biodiesel was subsequently blended with diesel fuel in different blend ratios of 0, 20, 40, 60, 80 and 100% by volume of biodiesel and were later tested in a compression ignition engine. Brake thermal efficiency and specific fuel consumption were observed to be worse with biodiesel fuel blends particularly at higher engine load above 50%. However, NOx emission generally decreased with increasing blend ratio across all engine load, with greater reduction observed at higher engine load. Similar observation can also be concluded for CO emission. In contrast, lower hydrocarbon (HC) emission from the biodiesel fuel blends was only observed for blend ratios no higher than 40%. Particulate emission from the biodiesel fuel blends did not pose an issue given its comparable smoke opacity to diesel observed during the engine test. The in-cylinder peak pressures, temperature and heat release rate of biodiesel fuel blends were lower than diesel. Overall, biodiesel fuel blends exhibited shorter ignition delays when compared to diesel fuel.