Investigation of the effects of co3o4 nanoparticle-added diesel and diesel/biodiesel blended fuels on diesel engine combustion, performance and exhaust emissions

Biodiesels can be used in diesel engines both in pure form and as a blend with petrodiesel. Nanoparticle additives enhance the fuel properties of both diesel and pure or blended biodiesel, thereby increasing their usability. In this experimental study, 100 ppm cobalt oxide nanoparticle powder was added to diesel fuel and a blend containing canola biodiesel at a mass fraction of 20%. The effects of the resulting nano fuels on fuel properties, as well as the performance, combustion, and exhaust emission characteristics of a naturally aspirated, direct injection, four-stroke, single-cylinder, air-cooled diesel engine, were investigated. The experiments were conducted at engine speeds of 1800, 2400 and 3000 rpm and at engine loads of 3, 6, and 9 Nm. Experimental findings indicated that increasing engine speed elevated the maximum heat release rates, while higher engine loads led to increased maximum cylinder pressures. The addition of cobalt oxide nanoparticles to the fuels resulted in increased cetane number, calorific value, viscosity, density, and oxygen content. Furthermore, this nanoparticle additive advanced injection and combustion start points, shifted maximum cylinder pressure locations earlier, reduced ignition delays and peak heat release rates, prolonged combustion duration by delaying combustion end, and increased exhaust gas temperatures. In addition, it was observed that the effective thermal efficiency increased by an average of 4.26%, while the specific fuel consumption decreased by an average of 6.36%. From an exhaust emissions perspective, cobalt oxide nanoparticle additives generally increased nitrogen oxid e emissions, whereas they showed a reduction effect on soot emissions.