Comparative second-law analysis of internal combustion engine operation for methane, methanol, and dodecane fuels

Rakopoulos, C.D.; Kyritsis, Dimitrios C.

doi:10.1016/s0360-5442(01)00027-5

Cited by 147 publications

(48 citation statements)

References 11 publications

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“…Rakopoulos and Kyritsis [22] presented a theoretical study to calculate the combustion irreversibilities for a four-stroke, naturally-aspirated diesel engine operated with methane, methanol, and dodecane as fuels. In their study it was observed that lighter fuels result in less entropy than heavy fuels.…”

Section: Methodsmentioning

confidence: 99%

“…Sekmen and Yilbaşi [21] applied energy and exergy analysis to a direct injection diesel engine using Entropy 2016, 18, 387 3 of 18 petroleum diesel fuel and soybean oil methyl ester (SME). Rakopoulos and Kyritsis [22] presented a theoretical study to calculate the combustion irreversibilities for a four-stroke, naturally-aspirated diesel engine operated with methane, methanol, and dodecane as fuels. In their study it was observed that lighter fuels result in less entropy than heavy fuels.…”

Section: Introductionmentioning

confidence: 99%

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Energy and Exergy Analyses of a Diesel Engine Fuelled with Biodiesel-Diesel Blends Containing 5% Bioethanol

Kul

Kahraman

2016

Entropy

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Abstract:In this study, energy and exergy analysis were performed for a single cylinder, water-cooled diesel engine using biodiesel, diesel and bioethanol blends. Each experiment was performed at twelve different engine speeds between 1000 and 3000 rev/min at intervals of 200 rev/min for four different fuel blends. The fuel blends, prepared by mixing biodiesel and diesel in different proportions fuel with 5% bioethanol, are identified as D92B3E5 (92% diesel, 3% biodiesel and 5% bioethanol), D85B10E5 (85% diesel, 10% biodiesel and 5% bioethanol), D80B15E5(80% diesel, 15% biodiesel and 5% bioethanol) and D75B20E5 (75% diesel, 20% biodiesel and 5% bioethanol). The effect of blends on energy and exergy analysis was investigated for the different engine speeds and all the results were compared with effect of D100 reference fuel. The maximum thermal efficiencies obtained were 31.42% at 1500 rev/min for D100 and 31.42%, 28.68%, 28.1%, 28% and 27.18% at 1400 rev/min, respectively, for D92B3E5, D85B10E5, D80B15E5, D75B20E5. Maximum exergetic efficiencies were also obtained as 29.38%, 26.8%, 26.33%, 26.15% and 25.38%, respectively, for the abovementioned fuels. As a result of our analyses, it was determined that D100 fuel has a slightly higher thermal and exergetic efficiency than other fuel blends and all the results are quite close to each other.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Energy and Exergy Analyses of a Diesel Engine Fuelled with Biodiesel-Diesel Blends Containing 5% Bioethanol

Kul

Kahraman

2016

Entropy

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“…Minimum entropy generation analysis has been applied to thermal insulation problems involving minimum heat transfer at fixed temperature difference and thermal enhancement involving minimum temperature difference to exchange a fixed heat flux [2]. In the literature, there are numerous applications of entropy generation analysis to storage systems [5][6][7], fluid flow within technical devices [8][9][10], engines [11,12], heat exchangers [13,14] and desalination plants [15].…”

Section: Introductionmentioning

confidence: 99%

Entropy Generation Analysis of Wildfire Propagation

Guelpa

Verda

2017

Entropy

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Entropy generation is commonly applied to describe the evolution of irreversible processes, such as heat transfer and turbulence. These are both dominating phenomena in fire propagation. In this paper, entropy generation analysis is applied to a grassland fire event, with the aim of finding possible links between entropy generation and propagation directions. The ultimate goal of such analysis consists in helping one to overcome possible limitations of the models usually applied to the prediction of wildfire propagation. These models are based on the application of the superimposition of the effects due to wind and slope, which has proven to fail in various cases. The analysis presented here shows that entropy generation allows a detailed analysis of the landscape propagation of a fire and can be thus applied to its quantitative description.

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“…It aims to study the mass and energy flows into and out of the different engine systems in order to identify possible undesirable energy sinks affecting efficiency. A more refined approach consists of using both the first and second Law of Thermodynamics in order to perform an exergy-available energy-balance that takes into account irreversibility in engine processes such as combustion [173,174]. Previous approaches allow the identification of potential efficiency improvements by recovering part of the thermal energy loss, and particularly, the second one allows to find an upper bound for efficiency given the engine characteristics and its operating conditions.…”

Section: Heat Release Law Designmentioning

confidence: 99%

“…Another important issue of previous methods is that the complexity of the combustion process requires the assumption of an arbitrary HRL. In this sense, traditional thermodynamic processes such as constant volume, constant pressure and limited pressure combustions are assumed [173], or more sophisticated Wiebe functions are considered [174].…”

Section: Heat Release Law Designmentioning

confidence: 99%

Optimal Control for Automotive Powertrain Applications

Bernad¹

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To the geniuses of the past, who built our future; to those names in the shades, bringing our knowledge. They not only supported this work but also the world we live in.If you can solve it, it is an exercise; otherwise it's a research problem.-Richard Bellman e ResumenEl ControlÓptimo (CO) es esencialmente un problema matemático de bús-queda de extremos, consistente en la definición de un criterio a minimizar (o maximizar), restricciones que deben satisfacerse y condiciones de contorno que afectan al sistema. La teoría de CO ofrece métodos para derivar una trayectoria de control que minimiza (o maximiza) ese criterio.Esta Tesis trata la aplicación del CO en automoción, y especialmente en el motor de combustión interna. Las herramientas necesarias son un método de optimización y una representación matemática de la planta motriz. Para ello, se realiza un análisis cuantitativo de las ventajas e inconvenientes de los tres métodos de optimización existentes en la literatura: programación dinámica, principio mínimo de Pontryagin y métodos directos. Se desarrollan y describen los algoritmos para implementar estos métodos así como un modelo de planta motriz, validado experimentalmente, que incluye la dinámica longitudinal del vehículo, modelos para el motor eléctrico y las baterías, y un modelo de motor de combustión de valores medios.El CO puede utilizarse para tres objetivos distintos:1. Control aplicado, en caso de que las condiciones de contorno estén definidas. Puede aplicarse al control del motor de combustión para un ciclo de conducción dado, traduciéndose en un problema matemático de grandes dimensiones. Se estudian dos casos particulares: la gestión de un sistema de EGR de doble lazo, y el control completo del motor, en particular de las consignas de inyección, SOI, EGR y VGT.2. Obtención de reglas de control cuasi-óptimas, aplicables en casos en los que no todas las perturbaciones se conocen. A este respecto, se analizan el cálculo de calibraciones de motor específicas para un ciclo, y la gestión energética de un vehículo híbrido mediante un control estocástico en bucle cerrado.3. Empleo de trayectorias de CO como comparativa o referencia para tareas de diseño y mejora, ofreciendo un criterio objetivo. La ley de combustión así como el dimensionado de una planta motriz híbrida se optimizan mediante el uso de CO.Las estrategias de CO han sido aplicadas experimentalmente en los trabajos referentes al motor de combustión, poniendo de manifiesto sus ventajas sustanciales, pero también analizando dificultades y líneas de actuación para superarlas. Los métodos desarrollados en esta Tesis Doctoral son generales y aplicables a otros criterios si se dispone de los modelos adecuados. ResumEl ControlÒptim (CO)és essencialment un problema matemàtic de cerca d'extrems, que consisteix en la definició d'un criteri a minimitzar (o maximitzar), restriccions que es deuen satisfer i condicions de contorn que afecten el sistema. La teoria de CO ofereix mètodes per a derivar una trajectòria de control que minimitza (o maximitza) a...

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Comparative second-law analysis of internal combustion engine operation for methane, methanol, and dodecane fuels

Cited by 147 publications

References 11 publications

Energy and Exergy Analyses of a Diesel Engine Fuelled with Biodiesel-Diesel Blends Containing 5% Bioethanol

Energy and Exergy Analyses of a Diesel Engine Fuelled with Biodiesel-Diesel Blends Containing 5% Bioethanol

Entropy Generation Analysis of Wildfire Propagation

Optimal Control for Automotive Powertrain Applications

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