The use of engines is necessary to keep the world moving. Such engines are fed mainly by fossil fuels, among these, the diesel. The operation and the behavior of engines in different thermodynamic cycles, with common fossil fuels, it is still challenging but, in general, it has well known and documented data. On the other hand, for alternative fuels, there is still demand of experimental data, particularly considering that it is desirable, most of the times, the use of a system with dual mode (reversible). Such systems are called Dual-Fuel, it brings a greater degree of freedom, but imply in technological challenges. In this paper we used an engine operating with single cylinder direct injection diesel and port ethanol injection system in Dual-Fuel mode with a 100% electronically controlled calibration. The methodology applied was, once the engine calibration was given to achieve the best specific fuel consumption or the MBT (Maximum Brake Torque) in each load condition, to gradually substitute the diesel oil by ethanol in compliance with the requirements established. Comparisons were made among working conditions considering the rate of diesel substitution and the energy indicated efficiency. Initially, the flow structure in the combustion chamber was tested in both 'quiescent' and high "swirl" modes. Compression ratios were adjusted at 3 different levels: 14:1, 16:1 and 17:1. It was tested two injectors, the first one of 35 g/s and another of 45 g/s. Regarding pressure diesel injection, 4 levels were investigated namely 800, 1000, 1200 and 1400 bar. (C) 2014 Elsevier Ltd. All rights reserved.