Análise Exergética de um Motor a Combustão

Abstract

Even today, the knowledge about physical phenomena and the accurately identification of the processes that happens in an internal combustion engine are quite outdated, to the detriment of practical knowledge. Therefore, this work proposes the construction of a theoretical model capable of simulating a gasoline-powered spark ignition engine, considering the finite duration of combustion, the heat transmission of the gases to the cylinder walls and variation of the parameters of the combustion processes. admission and exhaustion. The modeling was carried out through a numerical simulation based on the Euler method, incrementing a thermodynamic model according to the developed theoretical load. The geometric modeling of the engine, the effect of the energy release law and the heat transfer effect were considered. The heat release function, in addition to its usual application, was used to simulate the effect of opening and closing the intake and exhaust valves. The parameterization of the model was based on data from a competition engine, Baja SAE, which is a challenge for engineering students where a prototype vehicle with off-road capability must be developed. Baja SAE competition regulation, establishes an universal engine, in this sense, the conclusions obtained in this project tend to obtain a practical result in a enviroment where the elimination of losses, such as the understanding of the process, should means an advantage over to the other competitors. Each result was compared with other studies carried out on the subject, pointing to combustion as the main source of irreversibilities and the advancement of the combustion start angle as a way to improve the performance of the engine in question