<div class="section abstract"><div class="htmlview paragraph">In this work, it is presented an energetic and exegetic analysis of a single-cylinder, spark ignition, air-cooled Robin EY15 internal combustion engine, considering variations in engine speed and load level. The complete engine is defined as the control volume, which has as mass flows the intake air, fuel, exhaust gases and cooling air, and as energy flows the heat provided by the fuel, the net power and the heat losses. The analysis is performed using experimental data captured under engine speeds between 1500-4600 min<sup>-1</sup> and load levels (throttle valve opening) between 25-100 %. Through the analysis it is found that the maximum net and exergy efficiencies of the engine are 14.1 % and 13 % respectively. It is also found that the main energy evacuation ways are cooling air and miscellaneous losses, which represent, respectively, between 24.3-73.6 % and 9-61 % of the energy provided by the fuel, of which only 6-9.7 % and 22.7-34.7 % are exergy. The rate of exergy destroyed varies between 69.6-89.7 %.</div></div>