Understanding the Effect of Oxygenated Additives on Combustion Characteristics of Gasoline

Abstract

Laminar burning speed and ignition delay time behavior of iso-octane at the presence of two different biofuels, ethanol and 2,5 dimethyl furan (DMF), was studied in this work. Biofuels are considered as a better alternative source of fossil fuels. There is a potentiality that combustion characteristics of iso-octane can be improved using biofuels as an oxygenated additive. In this study, three different blending ratios of 5%, 25%, and 50% of ethanol/iso-octane and DMF/iso-octane were investigated. For laminar burning speed calculation, equivalence ratio of 0.6–1.4 was considered. Ignition delay time was measured under temperature ranges from 650 K to 1100 K. Two different mechanisms were considered in numerical calculation. These mechanisms were validated by comparing the results of pure fuels with wide range of experimental and numerical data. The characteristic change of iso-octane with the presence of additives was observed by comparing the results with pure fuel. Significant change was observed on behavior of iso-octane at 50% blending ratio. A comparison was also done on the effect of two different additives. It has found that addition of DMF brings significant changes on iso-octane characteristics comparing to ethanol.

Laminar Flame Characteristics of 2,5-Dimethylfuran (DMF) Biofuel: A Comparative Review with Ethanol and Gasoline

“…Clearly, the most important reactions are the light hydrocarbon reaction and the reaction that separates the H atom from the CH3 radical via O2-or OH. Therefore, the carbon chain branching reactions, thereby increasing the combustion rate, are caused by the reactions that separate the H atom from the CH3 group such as C2H3+O2→CH2CHO+H and C2H2+O→H+HCCO (Roy et al, 2019) (Vinayagam et al, 2021). In particular, compared with the case of lower equivalence ratios, the reaction of abstracting the H atom (CH3+OH→CH2OH+H) by the OH radical at a higher equivalence ratio was revealed to be more significant.…”

“…This is due to the influence of the equivalent ratios and mixing ratios of the DMF on the flame. Sensitivity analysis on LBV of DMF-air mixture at different equivalence ratios, at 393K and 1 atm (Roy et al, 2019) Interestingly, the reaction of H atom iso-addition to the DMF producing MF was determined to be an important contributor to the DMF consumption in the case of an uncompressed flame first (Togbé et al, 2014), showing approximately approx. 8.7% and 6.1% for the case XF = 0.14 and XF = 0.24.…”

“…Fig 7.Sensitivity analysis on LBV of DMF-air mixture at different equivalence ratios, at 393K and 1 atm(Roy et al, 2019) …”

A New Detailed Ethanol Kinetic Mechanism at Engine-Relevant Conditions

“…It has a high energy density which makes it attractive as a unique fuel. Among many oxygenated additives, ethanol has a long history, and it is already being used as one of the important additives in gasoline. − The addition of ethanol with gasoline improves the octane number and decreases the emission. It is expected that using ethanol as a base fuel can decrease the pressure on fossil fuels and at the same time decrease the associated environmental pollution.…”

“…It has a high energy density which makes it attractive as a unique fuel. Among many oxygenated additives, 1 ethanol has a long history, and it is already being used as one of the important additives in gasoline. 2−10 The addition of ethanol with gasoline improves the octane number and decreases the emission.…”