The automotive sector is increasingly focusing on improving the efficiency of propulsion systems to reduce pollutant and carbon dioxide emissions. Traditional internal combustion engines, however, do not always operate under optimal conditions, driving research toward alternative solutions that minimize system losses. In this context, free-piston engines offer the advantage of optimized combustion through a variable compression ratio, which enhances efficiency under partial load conditions and enables the use of different types of fuels. Furthermore, the absence of a crankshaft reduces frictional losses, further improving system performance. This thesis analyzes the behavior of a free-piston engine with an opposed configuration, examining the influence of operational parameters and conditions on its performance.