Revisão bibliográfica sobre combustíveis renováveis e suas misturas aplicadas a motores de combustão interna

Abstract

The use of ethanol, pure or mixed with gasoline in internal combustion engines with spark ignition as well as biodiesel and its mixture with diesel in engines with compression ignition is well established. This indicates that the use of renewable fuels is an appropriate alternative in the short term, as they demand less changes in the engines of vehicles already produced and configure lower costs for individuals. Although the replacement of internal combustion engines with electric motors is gaining more and more strength, it is still a distant reality from Brazilians, as new electric vehicles have a high acquisition cost and the modification of a non-electric vehicle would require high investment and major interventions. Thus, it is understood that the use of renewable sources is still the best alternative given its lower cost for use, generating a more immediate result. Corroborating, technological advances have led to studies on the development and application of new fuels and new mixtures, adding to the use of ethanol and biodiesel. Given this context, this study aimed to carry out a literature review on the different renewable fuels and mixtures of these, seeking to analyze in a comparative way the necessary changes in the engines, their economic and environmental advantages. The results showed that biodiesel is still the main object of study within the evaluated articles. Studies confirm the effectiveness of reducing emissions when using biodiesel and another favorable point for its use is the possibility of using the storage and fuel supply systems that already exist in most vehicles. Biogas and hydrogen are fuels that are gaseous and have shown increasing attention in the evaluation of researchers and their use also results in the reduction of carbon monoxide emissions. However, the use of these gaseous fuels requires adaptations in the fuel injection and storage systems, which would generate the need for greater investment so that they are applied to vehicles that are already in circulation. Despite this point, hydrogen offers advantages to be able to be applied also in fuel cells for electric vehicles.