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It has been largely announced that automotive industry is going through a disruption moment regarding applied powertrain technologies due to the efforts to decrease CO2 and pollutant gases emission, mainly through related legislations of different countries and regions. European and Asian future legislations are going to demand some electrification introduction, whether hybrid or fully electric, but even different technologies such as fuel cells and synthetic fuels over the next few years. In Brazil, with the upswing of biofuels use, considering a well to wheel CO2 emission calculation, the usage of hydrated ethanol or ethanol mixed up with gasoline in different proportions is a great solution for a continuous and progressive automotive fleet decarbonization, in parallel or associated with electrification, in a favorable pace for the market conditions.

It can be said that the greatest engineering challenge of mobility it is not related to the energy shortage, but to its generation and sustainable use. In this context, the growing use of biofuels by high performance internal combustion engines represents a sustainable alternative from the economic, technological, social and environmental point of view. In some regions of the planet, the modern electric and hybrid vehicles may not be the most sustainable choice, since they face many obstacles regarding clean energy generation, reduced recharging station network, limited autonomy, expensive vehicle prices, and battery recycling. In Brazil since its launching in 2003, the fleet of Flex-Fuel vehicles moved by either ethanol or gasoline is ever increasing. It is worth mentioning that the biofuel has physical and chemical properties that could make its use more efficient than it is nowadays.

A CFD three-dimensional analysis of an internal combustion engine was carried out to evaluate the gasoline-ethanol E27 fuel spray and flow characteristics using variable valve timing (VVT) technology. In this study, the fuel injection has been made using port fuel injection (PFI) and the simulations modeled two conditions of valve timing: baseline and retarding the intake valve opening (IVO) 40°. The dynamic performance of this numerical model was validated comparing simulation results of cylinder pressure, mass burned fraction, cylinder temperature, and heat release with experimental data. The effects of in-cylinder fluid flow patterns, such as tumble and swirl, on combustion were numerically investigated for the two studied conditions and it was verified an extreme reduction of swirl when IVO is retarded, besides differences in tumble and cross-tumble.

The analysis of the air motion inside the cylinders of an internal combustion engine constitutes a very important step during engines design. It is already known that its movement, normally decomposed in tumble and swirl motion, is totally related to the majority of phenomena which occur inside cylinder, like fuel evaporation, mixture formation or flame propagation. The use of mechanical devices in the intake system represents an interesting option in the attempt of optimizing the airflow and finding the best condition for maximum power and minimum specific fuel consumption. Devices like flow boxes, which control the airflow and change its main characteristics before entering the cylinder, by obstructing the air and changing its directions, are one possibility. Based on this idea, this paper presents a numerical analysis of the utilization of a flow box in the intake system of a spark ignition engine.

Recently many government Acts (Inova Energia, Inovar-Auto, RenovaBio) [1, 2, 3] have been implemented in order to expand the use of biofuels in Brazil. Besides the fulfillment until 2030 of the commitment assumed at the COP21[4] to reduce in 43% the gas emission contributing to the greenhouse effect, the expansion of the use of biofuels is important to assure regularity in the supply of fuels to the automotive sector in the next 15 years. In this context, it is worth mentioning a special characteristic of the Flex-Fuel engines that equip the majority of the automobiles in Brazil since their launching in 2003. The maximum compression ratio of these engines depends on the knocking characteristics of the gasoline, but usually an intermediate value, nearer to the ideal value for gasoline, is a compromise.