Augusto César Teixeira Malaquias’s research while affiliated with Federal University of Minas Gerais and other places

The growing demand for reduced fuel consumption and increased energy efficiency in internal combustion engines underscores the need for continuous advancements in engine technologies. At the same time, the significance of refining driver behavior cannot be ignored, as it stands as a crucial instrument in reducing unnecessary fuel expenses and mitigating escalated levels of pollutant emissions. In this sense, the accurate estimation of fuel consumption is a fundamental prerequisite for the applications of fuel control measures on fuel consumption. Although most modern vehicles offer fuel consumption data assessed by the electronic central unit, this information is primarily designed to provide users with an estimate of their momentary average consumption, without any assurance from manufacturers regarding the reliability of this data. Most of the initiatives aimed at measuring fuel consumption require invasive approaches, and there is still a lack of studies addressing non-invasive methods to evaluate the total fuel consumption, especially for Otto cycle engines operating with pure ethanol and a mixture of gasoline and ethanol. In this regard, the objective of this work is to develop a non-invasive method for the real-time fuel measurement of internal combustion engines based on the Otto cycle with a common rail fuel injection system. The proposed technique requires only the measurement of the electrical signal pulses sent from the engine control unit to the fuel injector and does not affect the performance or operation of the engine in any way. The measurement system was built using low-cost electronic components, and its accuracy was evaluated using a single-cylinder research engine (SCRE). A series of 32 tests were performed, considering four different engine loads, four different speeds, and two different fuels, ethanol (E100) and gasoline and ethanol blend (E27). The results achieved were superior to those obtained with electromechanical sensors. The results obtained by measuring the fuel consumption with the proposed methodology showed a maximum percentage error of ± 2.85% for ethanol (E100) and ± 3.30% for a blend of gasoline with 27% ethanol (E27).

The management of the global energy resources has stimulated the emergence of various agreements in favor of the environment. Among the most famous are the Conference of Parties (COP) and Route 2030, which aim to limit global warming to 1.5 °C by reducing the energy consumption and global emission levels. In order to comply with the international standards for energy consumption and pollutant emissions, the Brazilian government has been promoting the expansion of biofuels in the national energy matrix. Considering this scenario, the development of a novel internal combustion engine for the exclusive use of ethanol as a fuel, equipped with state-of-the-art technologies and employing modern design concepts, consists of an innovative and promising pathway for future Brazilian mobility, from both environmental and technological outlooks. In this sense, this work presents a method to determine the main engine dimensions as part of the initial process for a new ethanol prototype engine development. The Brazilian biofuel was selected due to its physicochemical properties, which allow the engine to achieve higher loads, and also due to its large availability as a renewable energy source in the country. Furthermore, a port water injection system was fitted to the engine in order to assist the combustion process by mitigating the knock tendency. The predicted overall engine performance was obtained by carrying out a GT-PowerTM 1D-CFD simulation, whose results pointed to a maximum torque of 279 Nm from 2000 to 4000 rpm and an indicated peak power of 135 kW at 5500 rpm. With a maximum water-to-fuel ratio of 19.2%, the engine was able to perform its entire full load curve at the MBT condition, a fact that makes the WI approach along with the ethanol fuel a very attractive solution. As a result of the specific design and optimization of each geometric parameter for this unique ethanol engine, a maximum indicated fuel conversion efficiency of 45.3% was achieved. Moreover, the engine was capable of achieving over 40% of the indicated fuel conversion efficiency in almost its entire full load curve.

The growing pressure to comply with environmental agreements that establish strict limits concerning pollutant emissions in the atmosphere has been stimulating a prominent technological development in the area of internal combustion engines. Recently, advanced combustion modes and the expanding adoption of biofuels are among the most explored aspects to minimize the environmental impact of modern propulsion systems. The dual-fuel combustion mode is a well-known strategy that has been studied since the early 1900s as an effective means for improving the fuel conversion efficiency of compression ignition engines. In recent years, this approach has been extended to spark-ignition engines and has shown promising results related to the combination of fuels normally used in the Otto cycle, with reduced fuel consumption, lower exhaust gaseous emissions and performance improvements. In this sense, the purpose of this article is to provide a concise review of the main state-of-art literature research covering the dual-fuel mode in spark-ignition engines, with special attention to the use of renewable and alternative options to reduce the impact of fossil fuels.

The automotive industry is experiencing a revolutionary moment in search of reducing the carbon footprint from its activities. Despite the demand for lower pollutant vehicles, there is no need for a complete disruption of the current industrial production processes. Notably, electric vehicles have been promoted by some parties as the only and best solution for the sustainable future of mobility, to the detriment of the internal combustion engine. This tendentious point of view, although controversial and potentially dangerous, has been gaining strength especially after the pandemic started in 2019, when a considerable reduction in the circulation of the fleet worldwide was observed. Therefore, this work aims to demonstrate the importance of a diversity of solutions for the sustainable future of the transport sector. The risks of a technology ban were examined, as well as the reasons why the development of internal combustion engines, alongside biofuels, is still and will continue to be necessary for cleaner mobility. Moreover, an investigation towards the real responsible for global emissions showed that electricity generation, not automobiles, is the major cause of atmospheric pollution.

This work reports the experimental study of a single-cylinder compression ignition engine fueled with a renewable diesel from sugarcane called farnesane. The engine is representative of current small-scale power generation in very isolated rural areas existing in Brazil. A complete experimental assessment was made on engine combustion, performance, and pollutant emissions at 1800 rpm under different loads (from 4 to 7 bar IMEP). Results showed reduced values for the ignition delay, in-cylinder peak pressure and mean temperature when using farnesane compared to conventional diesel fuel, as well as lower heat release rate peaks at the premixed combustion phase and shorter diffusion combustion duration. Physicochemical properties differences, such as cetane number, H/C ratio and the biofuel paraffinic structure led to interesting emission behavior. Farnesane reduced NOx emissions by up to 34% (and further 48.6% using EGR), and particulate matter by up to 92%. Despite the higher in-cylinder peak pressure and greater fuel conversion efficiency for diesel fuel at the highest load, the biofuel exhibited gains of up to 3.3% in combustion efficiency and 5.9% in fuel conversion efficiency at intermediate and lower loads. Such improvements are closely related to the HC and CO levels depletion and the absence of aromatic compounds.