The performance and exhaust emissions investigation of a diesel engine using γ-Al2O3 nanoparticle additives to biodiesel

Presently, the world faces a major crisis of energy demand. An increase in the petroleum price and exhaustion of fossil fuel resources make it more concerning. In this scenario, the usage of biodiesels derived from vegetable oils is considered a promising alternate fuel. The present study deals with the extraction of biodiesel from palm oil methyl ester (PME), which was derived from palm seed oil by the two-step esterification process. The two-step process consists of acid-catalyzed pretreatment, followed by alkaline-catalyzed transesterification. The extracted biodiesel was tested on a single-cylinder four-stroke direct-injection water-cooled diesel engine at a constant speed of 1500 rpm at various loads. Further, the performance and exhaust emissions of the engine were also studied at different dosage levels of gamma-Al2O3 nanoparticle additive. The results showed that the brake thermal efficiency was improved by 8% when the nanoparticle additive dosage level was varied from 25 to 100 ppm, and a maximum improvement was observed at dosing levels of 25 and 75 ppm. Specific fuel consumption was reduced up to 0.05 kg/kWh at 80% load with the addition of 25 ppm. The carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxide (NOx) and hydrocarbon (HC) emissions were reduced to a greater extent with the addition of gamma-Al2O3 nanoparticle additive, when compared to the biodiesel without gamma-Al2O3 nanoparticle at all load conditions of the engine. The dosage of nanoparticle to biodiesel fuel results in appreciably improved engine efficiencies, lower values of smoke, and lower CO and HC emissions. Thus, the experimental results proved that nanoparticle-added PME is one of the most suitable alternatives to diesel fuel.