GDI flex fuel engine: Influence of different fuels on the performance

Abstract

The internal combustion engine has been the main source of automotive propulsion for more than 100 years, but nowadays is facing challenges to significantly increase efficiency and reduce pollutants in the path to a low carbon mobility world. In this scenario, several developments have been implemented in the last years and new researches are being developed aiming high efficient and low emission vehicles. More stringent specifications for the fossil fuels and their blends with biofuels can play an important role to reduce carbon footprint of these new engines. In Brazil, since the 1970’s ethanol is widely used for spark ignited engines, either pure or blended in the gasoline (Brazilian gasoline). Brazilian flex fuel vehicles, which can run on hydrous ethanol, Brazilian gasoline or any mixture of these fuels, were released in 2000’s and represent nowadays over 90% of national light duty vehicles production. More recently, gasoline direct injection (GDI) technology was released at Brazilian flex fuel engines. Regarding fuel market, imported gasoline increased its share in recent years and although the compliance with the Brazilian specification, some properties may have significant differences compared to the ones of the average gasoline produced in Brazil. Results of performance, fuel consumption and combustion parameters of a GDI flex fuel engine running on hydrous ethanol and two different gasolines, one imported and other produced in Brazil, are shown in this paper. It is commented that flexibility to use gasoline and ethanol should be accompanied with more sophisticated engine hardware and control software to better explore the potential of the different fuels, and that different types of gasolines can affect many engine performance parameters, although this can be minimized adopting more tight fuels specifications. It is concluded that flex fuel engine designs and calibrations could be improved to obtain optimized performance with different fuels.