Desenvolvimento de um sistema de combustão com ignição por pré-câmara passiva operando com etanol hidratado

Abstract

The transport sector has undergone profound changes in recent years due to the need to reduce pollutant gas emissions and their impact on the environment. The replacement of internal combustion engines by electric propulsion systems has been publicized as the solution for the future of mobility, but the negative aspects and challenges for the implementation of this technology are often mitigated or even omitted. Technologies that take advantage of the potential of the local energy matrix, considering the geographic, demographic and social characteristics of each country and the increase of solutions diversity for the sustainable future of the transport sector are indispensable. Advanced ignition systems, such as pre-chamber ignition, can improve the combustion process of engines, increasing fuel conversion efficiency and reducing the emission of polluting gases. Therefore, the present work developed and optimized a pre-chamber ignition system applied in a single-cylinder research engine operating in stoichiometric condition and fueled with hydrated ethanol. The experiments were carried out on the AVL 5495 single-cylinder research engine installed on the DynoDur 160 active dynamometer, while numerical simulations were performed using commercial programs based on the finite volume method, both unidimensional applying the GT-POWER program and three-dimensionally using the CONVERGE program. In the first phase of the research, 9 pre-chamber geometries were designed, built, tested and simulated. Based on these results, an analysis was carried out and the influence of the volume, number and configurations of the holes was investigated to choose the geometries to be tested in the second phase. Subsequently, the best two geometries from the second phase were optimized for the final tests of the third phase of the research. The configuration that presented the highest fuel conversion efficiency was the one with 1% volume and four lateral holes of 2 mm in diameter, presenting a maximum positive variation of 4.8% in relation to the SI configuration. Furthermore, this configuration showed positive variations in fuel conversion efficiency in 6 of the 8 operating points tested. Regarding pollutant emissions, a maximum reduction of 5.86 g/kWh in NOx emissions was observed for the prechamber with 2.5% of volume, central hole of 3 mm in diameter and 4 lateral holes of 2 mm in diameter.