Avaliação computacional da operação de um motor de ignição por centelha AP 1,8l utilizando o método de análise de três pressões

Abstract

The planet is currently facing the consequences of greenhouse gas emissions, which have been occurring since the industrial revolution. With the introduction of internal combustion engines, this problem has been exacerbated. Currently, countries and regulatory agencies are working together to establish goals aimed at reducing the impact of fossil fuels on the atmosphere. Additionally, studies are being conducted on the development of mechanisms to reduce emissions from internal combustion engines (ICE), as well as to promote the use of energy from renewable sources and green fuels, in order to reduce dependence on fossil fuels. In this context, ethanol emerges as one of these alternative fuels. Brazil is a leader in this development, with an incentive plan for engines that use ethanol since the 1970s. Ethanol is considered a less polluting fuel than gasoline in terms of CO2 emissions. However, it faces the challenge of reducing emissions of aldehydes and hydrocarbons. For the development of internal combustion engines, computational simulation has proven to be a widely used tool as it can emulate combustion characteristics and predict engine behavior. The validation of these simulations is carried out through experimental data obtained in a test cell. In this context, the aim of this work is to validate a computational simulation performed in the GT-Power software using the Three Pressure Analysis (TPA) method on a Volkswagen AP 1.8 liters engine operating with ethanol. For this validation, geometric data of the engine, discharge coefficients, valve timing, torque, rotation, and fuel consumption are required. Additionally, pressures at the intake and exhaust ports, as well as in the cylinder, along with local average intake and exhaust temperatures, need to be acquired. The GT-Suite software was used to apply the method. The parameters of interest were selected according to the manual, considering an acceptable error margin of 5% to validate the results. Furthermore, pressure graphs as a function of crank angle were compared. Points of interest were defined under partial load (80 Kpa in the plenum) and full load, at rotations of 3000 rpm, 4500 rpm, and 6000 rpm, during stationary operation. The validation of this model is important to obtain data that would be costly or not feasible to acquire on an experimental test bench.