The rapid depletion of petroleum fuels and an era of ever-increasing price of them have led to an intensive search for alternative renewable fuels. Bio-fuels are attracting growing interest around the world, as a way to both reduce greenhouse gases and dependence on petroleum-based fuels. As a result of development of the global economy, the consumption of crude oil products is currently increasing rapidly[1, 2]. The sharp increase in petroleum prices, experiences with tighter supply and international instability have renewed concern about our dependence on petroleum imports. One of the strategies for reducing this dependence is to produce vehicles that run on alternatives to gasoline fuel. These alternative fuels include alcohols, gaseous fuels, renewable fuels, electricity, and fuels derived from coal[3–5]. The push to develop alternative fuels, although driven by energy security concerns, has been aided by concerns over the environment, because many alternative fuels lead to reductions in emissions of toxic chemicals, ozone forming compounds, and other pollutants, as well as greenhouse gases [6, 7]. The degradation of the global environment and the future foreseeable depletion of worldwide fossil fuel reserves have been the driving force to searching for alternative fuels that are sustainable and environmentally friendly. Ethanol fuel is one of the renewable fuels for addressing these issues. The potential of ethanol fuel in improving the performance of internal combustion engines has been recently the focus of many investigators [7–8].
Ethanol is a renewable energy source and can be produced from many bio-sources such as sugar cane, grain straw, maize and brown seaweed Ethanol, like most short-chain alcohols, is a flammable, volatile, and colorless liquid[8–10]. Bio-ethanol a distilled colorless liquid fuel obtained from numerous potential feedstock varieties such as sugar beet, wheat, corn, cassava, fruits, bagasse, barley, molasses, skim milk, potatoes, sorghum, switch grass and cellulose biomass such as wood, paper, straw and other cellulose wastes such as grasses, others include municipal solid wastes [12–14]. These various waste streams for ethanol production have their peculiar properties and generally are different. Ethanol as an alternative fuel, offers a sustainable economy by reducing the use of imported petroleum, CO2 emission and it boosts economy by providing value added market opportunities for the agricultural sector [15–18].
Blending of ethanol with benzene in Ethiopia, which saves over 1.8 million dollars in foreign currency of the country so far, was interrupted for three months since the major of ethanol provider sugar factory was shut down for maintenance. Ethiopia’s biggest sugar factory Finchaa, one of the three state-owned factories, was producing up to eight million liters of ethanol in a year. Finchaa ceased ethanol production on 2016, after supplying its product for exactly one year to Nile Petroleum Ethiopia, which was the sole oil blending company in Ethiopia [19]. The gasoline fuel replacement was regulated by the amount of ethanol in the blend. However, problems arise, due to the presence of water in the blend because commercially available ethanol is seldom found in anhydrous state and also the low-temperature miscibility of ethanol gasoline-water blends in flex fuel applications at -25°C and − 2°C [20–24]. It was found that the blend could be successfully used without phase separations within the tested temperature range. The performance and pollutant emissions of a four stroke SI engine operating on ethanol-gasoline blends of 0, 5, 10, 15, and 20% ethanol using artificial neural network was investigated by many researchers. They found a decrease in CO and HC emission with the introduction of ethanol into gasoline [25, 26].
As the percentage of ethanol increases, the emission characteristics improved. It is observed that the emission values of the HC and CO decreased when compared with that of pure gasoline. The brake thermal efficiency increases with the increase in the percentage of ethanol, E5 and E10 gave the best result for all measured parameters at a constant speed of 2000 rpm, thus ethanol may be used as an additive for gasoline [27–30]. Brake thermal efficiency increased as the volume percentage of ethanol fuel is increased in the bled. CO, HC and NOx emissions decreased with ethanol blends due to leaner air fuel blends [31–34]. The aim of this research work is to overcome the problem by modifying minor carburetor components to run with a blend of gasoline, water & ethanol to determine in what proportions hydrous ethyl alcohol and gasoline would mix to yield mixtures whose long-term stability was assure. The general objective of this research work is to improve and compare the performance and emission of gasoline; ethanol blend and hydrous ethanol blend fuels for spark ignition engines without major fuel systems component modification.