THEORETICAL ANALYSIS OF ATOMIZATION IN A DIESEL ENGINE FUELED WITH SOYBEAN OIL

Nury Audrey Nieto Garzón¹; Edson Bazzo¹; Amir Antônio Martins de Oliveira Júnior¹

¹ Federal University of Santa Catarina

doi:10.20906/CPS/COB-2015-1662

Resumo

The use of straight vegetable oils to replace diesel fuel in compression ignition engines is hampered by their poor atomization which leads to higher emissions and fouling of the surfaces of the combustion chamber. Here, the measured dynamic viscosity, density, and surface tension of soybean oil and its blends with diesel oil are used to predict the required temperature and blend proportion that would place the liquid fuel mixture within the atomization regime for common mechanical injectors with passage length/diameter of the nozzle of 2 to 6. The sprays are assumed to be injected in the pressurized air conditions typical of the combustion chamber of a small, naturally aspired, single cylinder, four strokes, direct injection diesel engine operating under nominal conditions, namely, fuel temperature from 90 °C to 150 °C, injection pressure from 160 bar to 200 bar, injection timing from 335 to 345 crankshaft angle, compression ratio of 17.3, and speed of 2200 rpm. The observed spray parameters were spray cone angle and average (SMD) droplet diameter. Influence of injection parameters and physical fuel properties was analyzed through the Analysis of Variance (ANOVA) of the results. Optimal operating conditions with soybean oil blends were identified.

Palavras-chave: biofuels; soybean oil; compression-ignition engines; atomization