Water injection enabling high efficiency flex fuel engines development 2021-36-0082

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.

This evolution, for instance, could be better planned to avoid impacts on PowerGrid and in internal combustion engines portfolio at market, since hybrid and electric vehicles which are still too costly and depend on subsidies for sale. This paper aims to show how water injection technology enables high efficiency flex fuel engines development, focused on ethanol performance, granting to Brazil a smoother path through future national fleet electrification. The energy efficiency in Mega Joules per Kilometer, improved through higher geometrical compression ratio, enhanced up to 7.3% (from 1.59 to 1.47 MJ/km) in a natural aspirated port fuel injection vehicle and up to 4.8% (from 1.85 to 1.76 MJ/km) in a turbocharged direct injection vehicle. Following this path, Flex Fuel engines can be better explored and improved if the right technology is used. Setting up the geometrical compression ratio focusing on ethanol properties could rise both ethanol and gasoline energy efficiency, as water injection can control knocking phenomena through managing combustion chamber temperature.