A Compendium of Methods for Determining the Exergy Balance Terms Applied to Reciprocating Internal Combustion Engines

2021 ◽  
pp. 1-39
Author(s):  
Bibhuti B. Sahoo ◽  
Maryom Dabi ◽  
Ujjwal K. Saha

Abstract Exergy analysis of the reciprocating internal combustion (IC) engines is studied by estimating various input and output energy transfer parameters concerning a dead state reference. Exergy terms such as fuel input, work output, cooling, and exhaust gas are measured and are set into the exergy balance equation to determine the amount of loss or destruction. Exergy destructions are found in many forms such as combustion (entropy generation), cylinder wall, friction, mixing, blow-by, and others. These exergy terms have been estimated by considering various factors such as engine type, fuel type, environmental condition, and others. In this article, the different methods employed in estimating these exergy terms have been reviewed. It attempts to make a compendium of these evaluation methods and segregates them under individual exergy terms with necessary descriptions. The fuel input measurement is mostly based on Gibb's free energy and the lower heating value, whereas its higher heating value is used during the fuel exergy calculation on a molar basis. The work output of the engines is estimated either from the crankshaft or by analyzing the cylinder pressure and volume. The exergy transfer with cooling medium and exhaust gas depends on the temperature of gas. The maximum achievable engine performance is quantified by estimating the exergy efficiency. This piece of study will not only provide a plenty of information on exergy evaluation methods of IC engines but will also allow the future researchers to adopt the appropriate one.

2015 ◽  
Vol 22 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Zbigniew Korczewski

Abstract The article discusses the problem of diagnostic informativeness of exhaust gas temperature measurements in turbocharged marine internal combustion engines. Theoretical principles of the process of exhaust gas flow in turbocharger inlet channels are analysed in its dynamic and energetic aspects. Diagnostic parameters are defined which enable to formulate general evaluation of technical condition of the engine based on standard online measurements of the exhaust gas temperature. A proposal is made to extend the parametric methods of diagnosing workspaces in turbocharged marine engines by analysing time-histories of enthalpy changes of the exhaust gas flowing to the turbocompressor turbine. Such a time-history can be worked out based on dynamic measurements of the exhaust gas temperature, performed using a specially designed sheathed thermocouple. The first part of the article discusses possibilities to perform diagnostic inference about technical condition of a marine engine with pulse turbocharging system based on standard measurements of exhaust gas temperature in characteristic control cross-sections of its thermal and flow system. Selected metrological issues of online exhaust gas temperature measurements in those engines are discusses in detail, with special attention being focused on the observed disturbances and thermodynamic interpretation of the recorded measuring signal. Diagnostic informativeness of the exhaust gas temperature measurements performed in steady-state conditions of engine operation is analysed in the context of possible evaluations of technical condition of the engine workspaces, the injection system, and the fuel delivery process.


Author(s):  
Volodumur Suvolapov ◽  
◽  
Andriy Novitskiy ◽  
Vasul Khmelevski ◽  
Oleksandr Bustruy ◽  
...  

The article analyzes scientific publications and literary studies of heat transfer processes in cylinders of internal combustion engines. The research of temperature fields in engines during their operation at different modes with the use of a software package and calculation module is presented. The results of modeling and thermo-metering in homogeneous and laminated engine cylinder liners are analyzed. Graphic dependencies and temperature distribution by cylinder wall thickness at maximum and minimum temperature on cylinder surface are given. On the basis of researches it is established that at laminating and pressing of inserts temperature fields in the engine cylinder change, temperature on an internal surface of the cylinder increases at laminating on 6,5 °С, and at pressing - on 4,5 °С. This is explained by the fact that the contact layer during plastification is in the zone of non-stationary mode, and when pressing the contact layer is in the zone of stationary mode and thus increases the thickness of the cylinder by 2 millimeters. It is established that the difference of minimum and maximum temperatures on the inner surface of the cylinder practically remains the same as that of a homogeneous cylinder. Thus, modeling becomes the most effective scientific tool in the development and implementation of long-term evaluation of options for improving ICE.


Author(s):  
Helgi S. Fridriksson ◽  
Bengt Sunde´n ◽  
Jinliang Yuan ◽  
Martin Andersson

Solid oxide fuel cells (SOFCs) have the attractive feature to be able to make use of hydrocarbon fuels in their operation by reforming the fuel into pure hydrogen, either internally or externally. This can open up for a smoother transition from the existing hydro-carbon economy toward a more renewable hydrogen economy. Since both SOFCs and internal combustion (IC) engines can make use of hydrocarbon fuels, it is of interest to examine the major differences in their utilization of the hydrocarbons and investigate how this type of fuel contributes to the power output of the respective systems. Thereby, various advantages and disadvantages of their reactions are raised. It was shown that even though there are fundamental differences between SOFCs and IC engines, both types face similar problems in their designs. These problems mostly include material design and operation management, but even problems related to the chemical reactions, e.g., carbon deposition for SOFCs and pollutant formation for IC engines.


Author(s):  
R. Lanzafame ◽  
M. Messina

Abstract It is important provide mathematical functions able to fit with great precision experimental data on gases properties, in order to obtain reliable results when computerized models on IC engines are used. On the basis of experimental data on equilibrium constants (for dissociation phenomena occurring during combustion process in IC engines) new mathematical functions have been determined to fit experimental data. In comparison to traditional fitting polynomials, these new mathematical functions present a great accuracy in matching experimental data. These new mathematical functions have the functional forms of a V order Logarithmic Polynomial, and their coefficients have been evaluated on the basis of the least square method. The new V order Logarithmic Polynomials have been determined for several dissociation reactions according to internal combustion processes applications. V order Logarithmic Polynomials have been implemented also to describe the trend of specific heat at constant pressure Vs temperature and enthalpy Vs temperature. These new Logarithmic Polynomials have been calculated for several gases and fuels for IC engines applications. The new Logarithmic Polynomials pointed out a better precision in comparison to the others polynomial functions used in literature, and the possibility to utilize a single Logarithmic Polynomial for a wide temperature range, according to a good accuracy with experimental data. Another advantage of the Logarithmic Polynomials is the possibility to extrapolate experimental data on a wide temperature range (25% of experimental T range) in order to supply to the experimental data shortage.


Author(s):  
Samiddha Palit ◽  
Bijan Kumar Mandal ◽  
Sudip Ghosh ◽  
Arup Jyoti Bhowal

Fast depletion of the conventional petroleum-based fossil fuel reserves and the detrimental effects of the pollutant emissions associated with the combustion of these fuels in internal combustion (IC) engines propelled the exploration and development of alternative fuels for internal combustion engines. Biodiesel has been identified as one of the most promising alternative fuels for IC engines. This paper discusses about the advantages and disadvantages of biodiesel vis-a-vis the conventional petro-diesel and presents the energetic performances and emission characteristics of CI engine using biodiesel and biodiesel-petrodiesel blends as fuels. An overview of the current research works carried out by several researchers has been presented in brief. A review of the performance analysis suggests that biodiesel and its blends with conventional diesel have comparable brake thermal efficiencies. The energy balance studies show that biodiesel returns more than 3 units of energy for each unit used in its production. However, the brake specific fuel consumption increases by about 9–14% compared to diesel fuel. But, considerable improvement in environmental performance is obtained using biodiesel. There is significant reduction in the emissions of unburned hydrocarbons, polyaromatic hydrocarbons (PAHs), soot, particulates, carbon monoxide, carbon dioxide and sulphur dioxide with biodiesel. But the NOx emission is more with biodiesel compared to diesel. A case study with Jatropha biodiesel as fuel and the current development status, both global and Indian, of biodiesel as a CI engine fuel have been included in the paper.


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