Simulação de motores de combustão interna multicilíndricos

Abstract

The significant environmental impact of the transportation sector, coupled with increasingly stringent emissions regulations, requires the development of new engine technologies and a reduction in dependence on fossil fuels. However, the predominance of internal combustion engines and petroleum-based fuels over the next few decades demands improvements in the efficiency of these engines. Optimizing internal combustion engines is greatly facilitated by the use of computational simulations, as they make it possible to reduce the experimental workload. In light of this, this work developed a 1D computational model, implemented in Fortran, capable of predicting combustion parameters of a multi-cylinder engine. For this, the already validated computational model of a single-cylinder engine with gas exchange was used as a base and a model that considers the flow between the duct junctions in the intake and exhaust manifolds was incorporated. The equations that describe the combustion process in this work’s computational model are based on a zero-dimensional one-zone model. However, to extend the model’s capabilities, a routine that uses a two-zone approach for the combustion process was also implemented, which may eventually be coupled to the computational model that simulates the multi-cylinder engine. This model was used to study the operation with ethanol in HCCI mode of the Renault BR-10 engine, a naturally aspirated 1.0 three-cylinder flex-fuel engine. The simulation results were compared with those of the original validated model in order to verify the accuracy and consistency of the predictions. The behavior of temperature and pressure inside the cylinder over combustion cycles, as well as efficiency parameters, was analyzed. Additionally, this model not only allows for the obtaining of combustion parameters but also provides data on the flow of gases in the ducts and junctions. The proposed model produced physically consistent results in predicting the parameters of this multi-cylinder engine.