Tag Archives: 2012). Since the quantity of the fuel directed into the cylinder depends above all on the engine load

341-350 R. Ilves, A. Küüt, T. Kikas and J. Olt
Influence of the drop size of bioethanol fuel in air-fuel mixture on combustion process of spark ignition engine
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Influence of the drop size of bioethanol fuel in air-fuel mixture on combustion process of spark ignition engine

R. Ilves*, A. Küüt, T. Kikas and J. Olt

Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56, EE51014 Tartu, Estonia; *Correspondence: risto.ilves@emu.ee

Abstract:

Abstract: Bioethanol is widely used as a fuel in spark ignition engines. Brazil and USA are among the largest producers of bioethanol in the world. In order to widen the use of bioethanol as a fuel in spark ignition engines, the combustion process has to be improved. This can be accomplished by dosing bioethanol air-fuel mixture into the engine. Thus, the smaller drop size of the fuel can be achieved than in the air-fuel mixtures formed in regular fuel supply systems. Decreasing the size of the fuel drops decreases evaporation time of the air-fuel mixture and therefore, increases the combustion velocity of the air-fuel mixture. This article gives an overview of using 96.4% bioethanol as a fuel in spark ignition engines when the fuel drop size in the air-fuel mixture directed to cylinder is smaller than in the air-fuel mixture formed in regular fuel supply systems. Results indicate that by decreasing the fuel drop size in the air-fuel mixture, fuel consumption of the engine decreased, while heat-release rate and the combustion velocity of the air-fuel mixture increased. Key words: bioethanol, fuel drop size, spark ignition engine, heat-release rate, combustion pressure.INTRODUCTIONSince developing the Otto-cycle engine by N.A. Otto, formation of the air-fuelmixture in the spark ignition engines has considerably improved. In the homogeneous mode, used in Otto-cycle engines, the entire combustion chamber is filled with the air-fuel mixture. In the newest technology, direct injection engines, the fuel is injected directly into the engine’s cylinder. Thus, not entire combustion chamber is filled with air-fuel mixture. The advantage of forming a stratified air-fuel mixture close to the spark plug electrode is that it can be ignited even at relative air-fuel ratio

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