Avaliação das emissões gasosa de um motor mono-cilindro ciclo Otto utilizando diferentes misturas de gasolina com etanol e adulterante.

Abstract

Gaseous emissions from burning fossil fuels are classified as the main causes of air pollution. By way of mitigation, Brazil regulates the use of ethanol in its energy matrix. However, the adoption of this alternative fuel, combined with the opening of the market for petroleum products, as solvents, incites commercialization of adulterated fuels (out of specifications defined by regulated quality parameters). Indeed, such conduct may result in decrease engine performance and increase air pollutants emissions. In this sense, the present study evaluates the effects of the ethanol and rubber solvent (SPB) addition in gasoline. Initially, tests were performed over quality parameters (distillation, ethanol content, color and appearance and density), then the consumption performance (mass and specific consumption) and finally gas emissions of carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx) and oxygen content (O2), measured in the exhaust. For this purpose, the formulations evaluated was pure gasoline mixed with 5, 10, 15, 20 and 25% v/v ethanol anhydrous content and gasoline blends with 20% v/v ethanol anhydrous, combined with 10, 20, 30 and 40% v/v of SPB content. The testing of quality parameters were conducted with NBR 9619, NBR 13992, NBR 14954 and NBR 7148 norms, while consumption performance and gaseous emissions were performed according to NBR 8178. In this case, we used a spark ignition single-cylinder engine, four-stroke, 196 cm³ and maximum power of 6.5 hp (4.85 kW) coupled to a generator operating under loads of 0, 600, 1200, 1800 and 2000 W. Measurements of concentrations of gases emitted in the exhaust were obtained through an automatic gas analyzer typically used in vehicle inspections, equipped with non-dispersive infrared (NDIR) for the detection of CO and HC and electrochemical sensors for the detection of O2 and NOx The results showed that, at a constant load of 2000 W, comparing emissions generated from pure gasoline and mixed with 25% v/v ethanol, there was reduction in the concentrations of CO, HC and NOx by 33%, 41% and 25% respectively. With respect to the consumption performance and emissions, while varying loads and comparing pure gasoline and ethanol 25% v/v, it was found increase in consumption of about 10%, although it was observed reductions of 122, 30 and 18% for CO, HC and NOx, respectively. With the addition of SPB increased consumption was about 10% and concentrations of CO and HC, by 38 and 16%, respectively, however, NOx emissions declined 15% (comparing 0 and 2000 W loads). In conclusion, it was found that the addition of ethanol in gasoline, while reducing consumption performance assists in reducing emissions of pollutant gases for both, constant and variable loads. Also adding SPB resulted in reducing consumption performance but increased emissions of CO and HC, despite being observed reduction in NOx emissions. For the tests of quality parameters, there were unsatisfying to reveal the presence of SPB in gasoline in some of the studied percentages.