International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 01 | Jan 2025
p-ISSN: 2395-0072
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Exergy Analysis of SI Engine during Combustion and Compression processes Based on Alternative Fuels as Methanol, Ethanol Santosh kumar Gupta1 1Department of Mechanical Engineering, Madan Mohan Malviya University of Technology, Gorakhpur, Uttar
Pradesh -273010, India 1Mechanical Engineering, Department of Technical Education, Uttar Pradesh-India ---------------------------------------------------------------------***--------------------------------------------------------------------Abstract - It is well known that the destruction of availability or exergy results from irreversible processes called combustion. For an adiabatic, constant volume system, the cycle's destruction of availability (energy) is investigated. This analysis was conducted without the use of experimental measures. For ethanol, methanol, propane, and octane-air combinations, the fraction of fuel availability that is destroyed by the irreversible processes is determined as a function of temperature, pressure, and equivalency ratio. When operating at greater temperatures, the combustion process generally results in less destruction of the fuel's available energy. Because they include some oxygen, methanol and ethanols differ greatly from gasoline. This study examines the fuel-air cycle and performs estimates for energy destruction during the compression, combustion, expansion, and exhaust process, taking into account changes in the equivalency ratio. With the adjustment in the equivalency ratio, the efficiency of the first and second laws is also determined for propane, ethanol, methanol, and iso-ocatne. Furthermore, depending on the specific operating conditions, equivalency ratio might have a large impact on the destruction of availability. In particular, the destroyed availability as a result of the combustion process varied from around 5 to 25% of the initial reactant availability under the study's conditions. There is a description of how these findings affect internal combustion engine combustion processes. Key Words: Availability, Petrol Engine, Equivalent Ratio, Air Fuel Ratio, Methanol, Ethanol 1.INTRODUCTION The availability of a given system is defined as the maximum useful work that can be obtained in a process in which the system comes to equilibrium with the surroundings or attains a dead state. The availability of energy conversion systems is one direct result. The second law of thermodynamics is a potent exposition of pertinent physical facts with many applications in engineering and energy conversion system operation. For example, the second law computes the maximum performance of thermal systems, establishes equilibrium conditions, determines the direction of processes, and identifies the components of processes which are used to determine overall performance. The framework provided by thermodynamics second type law allows for a deeper comprehension of combustion processes. thorough understanding of the energy conversion process. [1-3] Numerous investigations on the operation and exhaust emissions of spark-ignition engine (SI engine) based on blends of fuel like gasoline and alcohol have been conducted; result show that the emissions are reduced [8-13]. For example, Ceviz and Yüksel [14] looked into how blends of gasoline without ethanol affected emissions and cyclic variability in a spark-ignited engine. According to the study's findings, utilizing fuel mixes of ethanol-free gasoline decreased the coefficient of variation in the displayed mean effective pressure, as well as the concentrations of CO and HC emissions, while raising the CO2 content in the fuel blend up to 10% ethanol by volume[6]. In a gasoline engine, Çelik [18] employed ethanol as fuel at a high compression ratio. In comparison to running with pure gasoline fuel, he discovered that using E50 fuel at a high compression ratio enhanced engine power while lowering specific fuel consumption (sfc) and exhaust pollutants. In a different investigation, Shenghua et al. [35] ran three-cylinder Spark Ignition engine at full load using different methanol percentages in gasoline (10%, 15%, 20%, 25%, and 30%). They discovered that when the fuel blend's methanol content increased, the engine's power and torque dropped and the brakes' thermal efficiency increased. Gasoline-methanol mixes were also used as fuels in a port fuel injection (PFI) gasoline engine by Fan et al. [36] without any modifications. According to the study's findings, methanol-gasoline blended fuels had no effect on engine performance, and there was no discernible change in the cylinder pressure or heat release rate as the blended fuel's methanol concentration increased [37,38]. Ethanol, methanol, and propane are the alternative fuels under consideration. An engineer is interested in determining the most useful work that can be obtained from a system in a given state. [20,27,28] Obviously, the greatest amount of work will be produced only when the system's the ultimate condition is in harmony with its environment. In other words, until the system's interaction with the environment reaches a point where it can no longer function in any way. A system's availability is determined by the maximum amount of useful work which may be find throughout a process that ends when the system reaches with state of inactivity or equilibrium with its surroundings.[4] It is obvious that a system's availability is dependent
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