Eficácia de aditivo via tanque para combustível diesel na limpeza dos sistemas de pós-tratamento.

The need to reduce greenhouse gases (GHG) such as CO2, as well as other environmental contaminants caused by vehicle tailpipes, become fundamental for humanity. The combinations that driver to a significant fuel economy in the automotive segment are too complex and based on several physical, economical and technological factors, however in this work we tried to isolate the variables aiming to demonstrate only the influence of the viscosity grade from the lubricant used in the internal combustion engine (ICE). We performed tests on a popular vehicle, which is representative in the Brazilian market, powered by an 1,000 cm³ Otto engine, installed in a chassis dynamometer in an independent laboratory certified by INMETRO using the NBR 6601 and 7024 standards as reference, in urban and highway cycles, with engine oil in three different viscosities grades: SAE 5W-40, SAE 5W-30 and SAE 0W-20. To ensure only the viscosity change, these three fluids were blended with the same basic oil type and the same additive package, adjusting only the amount of viscosity modifier and the fractions of the base oils to meet the desired viscosity grade. The result showed that thinner oils reduce friction in the engine among its moving parts, reduce the pump losses and, therefore, an improvement on the fuel efficiency, as well as reduction in exhaust gas emissions. The results obtained in this study show that the fuel economy changing from a SAE 5W-40 oil to a SAE 5W-30 in this vehicle operating in this cycle was 0.91% and using the SAE 0W-20 fluid under the same conditions the reduction was 2.11%. The SAE 0W-20 viscosity grade proved a real benefit on hardware efficiency, helping on new environmental challenges and reducing the vehicle's operating cost to the end customer.