Using Fractal Modeling to Predict Flex-Fuel Engine Combustion Process with Different Gasoline-Ethanol Blends

Melo, Tadeu Cavalcante Cordeiro de; Machado, Guilherme Bastos; Matias, Filipe Augusto Serrão

doi:10.4271/2014-36-0162

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…Overall, the combustion characteristics such as pressure and HRR are improved with reducing ID for the increment in the ethanol content as shown in Figure 9. The CP of FFE increases with the increase of ethanol share, due to the higher‐octane value of ethanol, which allows advancing the spark timing based on the percentage of ethanol content in the air‐fuel mixture 85 . Also, the maximum cylinder pressure ( P max ) and knock limits are increased with the increase of ethanol percentage in FFE because of the better anti‐knocking quality of ethanol 86 .…”

Section: Flex‐fuel Engine Output Characteristics Under Steady‐state C...mentioning

confidence: 99%

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Critical review on recent progress of ethanol fuelled flex‐fuel engine characteristics

Azhaganathan

Ashok

2022

Intl J of Energy Research

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Summary Ethanol‐powered spark ignition (SI) engines have the potential to mitigate the twin crisis of fossil fuel depletion and exhaust emissions. However, the successful promotion of ethanol is hindered due to the restriction of fuel blend diversity and design features in the conventional SI engine. The fuel flexibility can be overcome by the use of flex‐fuel engine (FFE) technology with appropriate changes in engine design features for a wide range of ethanol blends. The understanding of FFE based on various technical aspects has greater potential in the automotive sector. Therefore, this review paper provides a holistic approach to critically analyze the various technical aspects of FFE. In this work, the application of ethanol blends on FFE output characteristics is reviewed critically considering the effects of engine operating conditions and parameters. Further, the impact of ethanol blends on material compatibility, cold starting characteristics, and unregulated emissions are analyzed. The outcome of the study shows that combustion and performance characteristics such as cylinder pressure(CP), heat release rate (HRR), and brake thermal efficiency (BTE) are improved in FFE operation due to the clean‐burning characteristics of ethanol blends. Also, carbon monoxide(CO) and hydrocarbon (HC) emissions decreased without any significant improvement in nitrogen oxides (NOx) emissions with a wide range of ethanol shares in FFE. Finally, this study summarizes the present status of research in FFE and creates a route towards the direction of multidisciplinary research need in the future that supports the application of different types of biofuels in FFE.

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Section: Flex‐fuel Engine Output Characteristics Under Steady‐state C...mentioning

confidence: 99%

“…The CP of FFE increases with the increase of ethanol share, due to the higher-octane value of ethanol, which allows advancing the spark timing based on the percentage of ethanol content in the air-fuel mixture. 85 Also, the maximum cylinder pressure (P max ) and knock limits are…”

Section: Ethanol Sharementioning

confidence: 99%

Critical review on recent progress of ethanol fuelled flex‐fuel engine characteristics

Azhaganathan

Ashok

2022

Intl J of Energy Research

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“…Following the research discussed above, much work, for example, [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] has been focused on the turbulent combustion in SI engines, along with experimental measurements. Most of the models developed using FES were quasi-dimensional models, where the zero-dimensional thermodynamic models were applied up to the time of ignition, and two zones, burned and unburned (these two zones are often subdivided into boundary layers and isothermal cores, and a crevice zone is sometimes added as well), were utilized for the duration of the combustion process.…”

Section: Introductionmentioning

confidence: 99%

Development of a fractal engine simulation model in a multidimensional simulation for the cold start process of a gasoline direct injection engine

Hall

et al. 2023

International Journal of Engine Research

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A fractal engine simulation (FES) sub-model was integrated into three-dimensional simulations for modeling turbulent combustion for a gasoline direct injection (GDI) engine. The FES model assumes that the effects of turbulence on flame propagation are to wrinkle and stretch the flame, and fractal geometry is used to predict the surface area increase and thus the turbulent burning velocity. Different formulas for the four sequential stages of combustion in SI engines are proposed to account for the changing effects of turbulence throughout the combustion process. However, most prior studies related to the FES model were quasi-dimensional simulations, with few found in multi-dimensional studies, and none under cold start conditions or stratified charges. This paper describes how the model was implemented into multidimensional simulations in CONVERGE CFD, and what the formulas are in the four sequential stages of combustion in SI engines. The capabilities of the FES model for simulating the cold start cases, under the conditions of the dramatically changing engine speed and mixture stratification in a complex engine geometry, are presented in this study. The FES model was able to not only simulate the steady-state cases with constant engine speed, but also predict the in-cylinder pressure traces in all four cylinders for the very first firing cycle with transient engine speed, and gave good agreement with the experimental measurements under these extremely transient conditions. The uncertain maximum fractal dimension was chosen as 2.37 in this research, and a simple linear correlation with engine speed was used to obtain the coefficient used in calculating the kernel formation time which controls the so-called combustion or ignition delay.

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Development of optimal engine control map for flex fuel application in ethanol powered direct injection spark ignition engine

Sathish Kumar,

Ashok,

Saravanan

et al. 2025

Fuel

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Using Fractal Modeling to Predict Flex-Fuel Engine Combustion Process with Different Gasoline-Ethanol Blends

Cited by 4 publications

References 11 publications

Critical review on recent progress of ethanol fuelled flex‐fuel engine characteristics

Critical review on recent progress of ethanol fuelled flex‐fuel engine characteristics

Development of a fractal engine simulation model in a multidimensional simulation for the cold start process of a gasoline direct injection engine

Development of optimal engine control map for flex fuel application in ethanol powered direct injection spark ignition engine

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