Thermodynamics and Statistical Mechanics
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Constant Volume Combustion Cycle for IC Engines
Constant Volume Combustion Cycle for IC Engines Jovan Dorić Assistant This paper presents an analysis of the internal combustion engine cycle in University of Novi Sad Faculty of Technical Sciences cases when the new unconventional piston motion law is used. The main goal of the presented unconventional piston motion law is to make a Ivan Klinar realization of combustion during constant volume in an engine’s cylinder. Full Professor The obtained results are shown in PV (pressure-volume) diagrams of University of Novi Sad Faculty of Technical Sciences standard and new engine cycles. The emphasis is placed on the shortcomings of the real cycle in IC engines as well as policies that would Marko Dorić contribute to reducing these disadvantages. For this paper, volumetric PhD student efficiency, pressure and temperature curves for standard and new piston University of Novi Sad Faculty of Agriculture motion law have been calculated. Also, the results of improved efficiency and power are presented. Keywords: constant volume combustion, IC engine, kinematics. 1. INTRODUCTION of an internal combustion engine, whose combustion is so rapid that the piston does not move during the Internal combustion engine simulation modelling has combustion process, and thus combustion is assumed to long been established as an effective tool for studying take place at constant volume [6]. Although in engine performance and contributing to evaluation and theoretical terms heat addition takes place at constant new developments. Thermodynamic models of the real volume, in real engine cycle heat addition at constant engine cycle have served as effective tools for complete volume can not be performed. -
Hybrid Electric Vehicles: a Review of Existing Configurations and Thermodynamic Cycles
Review Hybrid Electric Vehicles: A Review of Existing Configurations and Thermodynamic Cycles Rogelio León , Christian Montaleza , José Luis Maldonado , Marcos Tostado-Véliz * and Francisco Jurado Department of Electrical Engineering, University of Jaén, EPS Linares, 23700 Jaén, Spain; [email protected] (R.L.); [email protected] (C.M.); [email protected] (J.L.M.); [email protected] (F.J.) * Correspondence: [email protected]; Tel.: +34-953-648580 Abstract: The mobility industry has experienced a fast evolution towards electric-based transport in recent years. Recently, hybrid electric vehicles, which combine electric and conventional combustion systems, have become the most popular alternative by far. This is due to longer autonomy and more extended refueling networks in comparison with the recharging points system, which is still quite limited in some countries. This paper aims to conduct a literature review on thermodynamic models of heat engines used in hybrid electric vehicles and their respective configurations for series, parallel and mixed powertrain. It will discuss the most important models of thermal energy in combustion engines such as the Otto, Atkinson and Miller cycles which are widely used in commercial hybrid electric vehicle models. In short, this work aims at serving as an illustrative but descriptive document, which may be valuable for multiple research and academic purposes. Keywords: hybrid electric vehicle; ignition engines; thermodynamic models; autonomy; hybrid configuration series-parallel-mixed; hybridization; micro-hybrid; mild-hybrid; full-hybrid Citation: León, R.; Montaleza, C.; Maldonado, J.L.; Tostado-Véliz, M.; Jurado, F. Hybrid Electric Vehicles: A Review of Existing Configurations 1. Introduction and Thermodynamic Cycles. -
Recording and Evaluating the Pv Diagram with CASSY
LD Heat Physics Thermodynamic cycle Leaflets P2.6.2.4 Hot-air engine: quantitative experiments The hot-air engine as a heat engine: Recording and evaluating the pV diagram with CASSY Objects of the experiment Recording the pV diagram for different heating voltages. Determining the mechanical work per revolution from the enclosed area. Principles The cycle of a heat engine is frequently represented as a closed curve in a pV diagram (p: pressure, V: volume). Here the mechanical work taken from the system is given by the en- closed area: W = − ͛ p ⋅ dV (I) The cycle of the hot-air engine is often described in an idealised form as a Stirling cycle (see Fig. 1), i.e., a succession of isochoric heating (a), isothermal expansion (b), isochoric cooling (c) and isothermal compression (d). This description, however, is a rough approximation because the working piston moves sinusoidally and therefore an isochoric change of state cannot be expected. In this experiment, the pV diagram is recorded with the computer-assisted data acquisition system CASSY for comparison with the real behaviour of the hot-air engine. A pressure sensor measures the pressure p in the cylinder and a displacement sensor measures the position s of the working piston, from which the volume V is calculated. The measured values are immediately displayed on the monitor in a pV diagram. Fig. 1 pV diagram of the Stirling cycle 0210-Wei 1 P2.6.2.4 LD Physics Leaflets Setup Apparatus The experimental setup is illustrated in Fig. 2. 1 hot-air engine . 388 182 1 U-core with yoke . -
Novel Hot Air Engine and Its Mathematical Model – Experimental Measurements and Numerical Analysis
POLLACK PERIODICA An International Journal for Engineering and Information Sciences DOI: 10.1556/606.2019.14.1.5 Vol. 14, No. 1, pp. 47–58 (2019) www.akademiai.com NOVEL HOT AIR ENGINE AND ITS MATHEMATICAL MODEL – EXPERIMENTAL MEASUREMENTS AND NUMERICAL ANALYSIS 1 Gyula KRAMER, 2 Gabor SZEPESI *, 3 Zoltán SIMÉNFALVI 1,2,3 Department of Chemical Machinery, Institute of Energy and Chemical Machinery University of Miskolc, Miskolc-Egyetemváros 3515, Hungary e-mail: [email protected], [email protected], [email protected] Received 11 December 2017; accepted 25 June 2018 Abstract: In the relevant literature there are many types of heat engines. One of those is the group of the so called hot air engines. This paper introduces their world, also introduces the new kind of machine that was developed and built at Department of Chemical Machinery, Institute of Energy and Chemical Machinery, University of Miskolc. Emphasizing the novelty of construction and the working principle are explained. Also the mathematical model of this new engine was prepared and compared to the real model of engine. Keywords: Hot, Air, Engine, Mathematical model 1. Introduction There are three types of volumetric heat engines: the internal combustion engines; steam engines; and hot air engines. The first one is well known, because it is on zenith nowadays. The steam machines are also well known, because their time has just passed, even the elder ones could see those in use. But the hot air engines are forgotten. Our aim is to consider that one. The history of hot air engines is 200 years old. -
Generation of Entropy in Spark Ignition Engines
Int. J. of Thermodynamics ISSN 1301-9724 Vol. 10 (No. 2), pp. 53-60, June 2007 Generation of Entropy in Spark Ignition Engines Bernardo Ribeiro, Jorge Martins*, António Nunes Universidade do Minho, Departamento de Engenharia Mecânica 4800-058 Guimarães PORTUGAL [email protected] Abstract Recent engine development has focused mainly on the improvement of engine efficiency and output emissions. The improvements in efficiency are being made by friction reduction, combustion improvement and thermodynamic cycle modification. New technologies such as Variable Valve Timing (VVT) or Variable Compression Ratio (VCR) are important for the latter. To assess the improvement capability of engine modifications, thermodynamic analysis of indicated cycles of the engines is made using the first and second laws of thermodynamics. The Entropy Generation Minimization (EGM) method proposes the identification of entropy generation sources and the reduction of the entropy generated by those sources as a method to improve the thermodynamic performance of heat engines and other devices. A computer model created and implemented in MATLAB Simulink was used to simulate the conventional Otto cycle and the various processes (combustion, free expansion during exhaust, heat transfer and fluid flow through valves and throttle) were evaluated in terms of the amount of the entropy generated. An Otto cycle, a Miller cycle (over-expanded cycle) and a Miller cycle with compression ratio adjustment are studied using the referred model in order to evaluate the amount of entropy generated in each cycle. All cycles are compared in terms of work produced per cycle. Keywords: IC engines, Miller cycle, entropy generation, over-expanded cycle 1. -
Thermodynamics of Power Generation
THERMAL MACHINES AND HEAT ENGINES Thermal machines ......................................................................................................................................... 1 The heat engine ......................................................................................................................................... 2 What it is ............................................................................................................................................... 2 What it is for ......................................................................................................................................... 2 Thermal aspects of heat engines ........................................................................................................... 3 Carnot cycle .............................................................................................................................................. 3 Gas power cycles ...................................................................................................................................... 4 Otto cycle .............................................................................................................................................. 5 Diesel cycle ........................................................................................................................................... 8 Brayton cycle ..................................................................................................................................... -
An Analytic Study of Applying Miller Cycle to Reduce Nox Emission from Petrol Engine Yaodong Wang, Lin Lin, Antony P
An analytic study of applying miller cycle to reduce nox emission from petrol engine Yaodong Wang, Lin Lin, Antony P. Roskilly, Shengchuo Zeng, Jincheng Huang, Yunxin He, Xiaodong Huang, Huilan Huang, Haiyan Wei, Shangping Li, et al. To cite this version: Yaodong Wang, Lin Lin, Antony P. Roskilly, Shengchuo Zeng, Jincheng Huang, et al.. An analytic study of applying miller cycle to reduce nox emission from petrol engine. Applied Thermal Engineering, Elsevier, 2007, 27 (11-12), pp.1779. 10.1016/j.applthermaleng.2007.01.013. hal-00498945 HAL Id: hal-00498945 https://hal.archives-ouvertes.fr/hal-00498945 Submitted on 9 Jul 2010 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Accepted Manuscript An analytic study of applying miller cycle to reduce nox emission from petrol engine Yaodong Wang, Lin Lin, Antony P. Roskilly, Shengchuo Zeng, Jincheng Huang, Yunxin He, Xiaodong Huang, Huilan Huang, Haiyan Wei, Shangping Li, J Yang PII: S1359-4311(07)00031-2 DOI: 10.1016/j.applthermaleng.2007.01.013 Reference: ATE 2070 To appear in: Applied Thermal Engineering Received Date: 5 May 2006 Revised Date: 2 January 2007 Accepted Date: 14 January 2007 Please cite this article as: Y. -
Comparison of ORC Turbine and Stirling Engine to Produce Electricity from Gasified Poultry Waste
Sustainability 2014, 6, 5714-5729; doi:10.3390/su6095714 OPEN ACCESS sustainability ISSN 2071-1050 www.mdpi.com/journal/sustainability Article Comparison of ORC Turbine and Stirling Engine to Produce Electricity from Gasified Poultry Waste Franco Cotana 1,†, Antonio Messineo 2,†, Alessandro Petrozzi 1,†,*, Valentina Coccia 1, Gianluca Cavalaglio 1 and Andrea Aquino 1 1 CRB, Centro di Ricerca sulle Biomasse, Via Duranti sn, 06125 Perugia, Italy; E-Mails: [email protected] (F.C.); [email protected] (V.C.); [email protected] (G.C.); [email protected] (A.A.) 2 Università degli Studi di Enna “Kore” Cittadella Universitaria, 94100 Enna, Italy; E-Mail: [email protected] † These authors contributed equally to this work. * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +39-075-585-3806; Fax: +39-075-515-3321. Received: 25 June 2014; in revised form: 5 August 2014 / Accepted: 12 August 2014 / Published: 28 August 2014 Abstract: The Biomass Research Centre, section of CIRIAF, has recently developed a biomass boiler (300 kW thermal powered), fed by the poultry manure collected in a nearby livestock. All the thermal requirements of the livestock will be covered by the heat produced by gas combustion in the gasifier boiler. Within the activities carried out by the research project ENERPOLL (Energy Valorization of Poultry Manure in a Thermal Power Plant), funded by the Italian Ministry of Agriculture and Forestry, this paper aims at studying an upgrade version of the existing thermal plant, investigating and analyzing the possible applications for electricity production recovering the exceeding thermal energy. A comparison of Organic Rankine Cycle turbines and Stirling engines, to produce electricity from gasified poultry waste, is proposed, evaluating technical and economic parameters, considering actual incentives on renewable produced electricity. -
Heat Cycles, Heat Engines, & Real Devices
Heat Cycles, Heat Engines, & Real Devices John Jechura – [email protected] Updated: January 4, 2015 Topics • Heat engines / heat cycles . Review of ideal‐gas efficiency equations . Efficiency upper limit –Carnot Cycle • Water as working fluid in Rankine Cycle . Role of rotating equipment inefficiency • Advanced heat cycles . Reheat & heat recycle • Organic Rankine Cycle • Real devices . Gas & steam turbines 2 Heat Engines / Heat Cycles • Carnot cycle . Most efficient heat cycle possible Hot Reservoir @ T H • Rankine cycle Q H . Usually uses water (steam) as working fluid W . Creates the majority of electric power used net throughout the world Q C . Can use any heat source, including solar thermal, Cold Sink @ T coal, biomass, & nuclear C • Otto cycle . Approximates the pressure & volume of the combustion chamber of a spark‐ignited engine WQQ • Diesel cycle net H C th QQ . Approximates the pressure & volume of the HH combustion chamber of the Diesel engine 3 Carnot Cycle • Most efficient heat cycle possible • Steps . Reversible isothermal expansion of gas at TH. Combination of heat absorbed from hot reservoir & work done on the surroundings. Reversible isentropic & adiabatic expansion of the gas to TC. No heat transferred & work done on the surroundings. Reversible isothermal compression of gas at TC. Combination of heat released to cold sink & work done on the gas by the surroundings. Reversible isentropic & adiabatic compression of the gas to TH. No heat transferred & work done on the gas by the surroundings. • Thermal efficiency QQHC TT HC T C th th 1 QTTHHH 4 Rankine/Brayton Cycle • Different application depending on working fluid . Rankine cycle to describe closed steam cycle. -
3.5 the Internal Combustion Engine (Otto Cycle)
Thermodynamics and Propulsion Next: 3.6 Diesel Cycle Up: 3. The First Law Previous: 3.4 Refrigerators and Heat Contents Index Subsections 3.5.1 Efficiency of an ideal Otto cycle 3.5.2 Engine work, rate of work per unit enthalpy flux 3.5 The Internal combustion engine (Otto Cycle) [VW, S & B: 9.13] The Otto cycle is a set of processes used by spark ignition internal combustion engines (2-stroke or 4- stroke cycles). These engines a) ingest a mixture of fuel and air, b) compress it, c) cause it to react, thus effectively adding heat through converting chemical energy into thermal energy, d) expand the combustion products, and then e) eject the combustion products and replace them with a new charge of fuel and air. The different processes are shown in Figure 3.8: 1. Intake stroke, gasoline vapor and air drawn into engine ( ). 2. Compression stroke, , increase ( ). 3. Combustion (spark), short time, essentially constant volume ( ). Model: heat absorbed from a series of reservoirs at temperatures to . 4. Power stroke: expansion ( ). 5. Valve exhaust: valve opens, gas escapes. 6. ( ) Model: rejection of heat to series of reservoirs at temperatures to . 7. Exhaust stroke, piston pushes remaining combustion products out of chamber ( ). We model the processes as all acting on a fixed mass of air contained in a piston-cylinder arrangement, as shown in Figure 3.10. Figure 3.8: The ideal Otto cycle Figure 3.9: Sketch of an actual Otto cycle Figure 3.10: Piston and valves in a four-stroke internal combustion engine The actual cycle does not have the sharp transitions between the different processes that the ideal cycle has, and might be as sketched in Figure 3.9. -
Performance Analysis of a Diesel Cycle Under the Restriction of Maximum Cycle Temperature with Considerations of Heat Loss, Friction, and Variable Specific Heats S.S
Vol. 120 (2011) ACTA PHYSICA POLONICA A No. 6 Performance Analysis of a Diesel Cycle under the Restriction of Maximum Cycle Temperature with Considerations of Heat Loss, Friction, and Variable Specific Heats S.S. Houa;¤ and J.C. Linb aDepartment of Mechanical Engineering, Kun Shan University, Tainan City 71003, Taiwan, ROC bDepartment of General Education, Transworld University, Touliu City, Yunlin County 640, Taiwan, ROC (Received November 11, 2010) The objective of this study is to examine the influences of heat loss characterized by a percentage of fuel’s energy, friction and variable specific heats of working fluid on the performance of an air standard Diesel cycle with the restriction of maximum cycle temperature. A more realistic and precise relationship between the fuel’s chemical energy and the heat leakage that is constituted on a pair of inequalities is derived through the resulting temperature. The variations in power output and thermal efficiency with compression ratio, and the relations between the power output and the thermal efficiency of the cycle are presented. The results show that the power output as well as the efficiency where maximum power output occurs will increase with the increase of maximum cycle temperature. The temperature-dependent specific heats of working fluid have a significant influence on the performance. The power output and the working range of the cycle increase while the efficiency decreases with increasing specific heats of working fluid. The friction loss has a negative effect on the performance. Therefore, the power output and efficiency of the cycle decrease with increasing friction loss. It is noteworthy that the effects of heat loss characterized by a percentage of fuel’s energy, friction and variable specific heats of working fluid on the performance of a Diesel-cycle engine are significant and should be considered in practice cycle analysis. -
Developing of a Thermodynamic Model for the Performance Analysis
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 2 August 2018 doi:10.20944/preprints201808.0045.v1 Peer-reviewed version available at Energies 2018, 11, 2655; doi:10.3390/en11102655 Developing of a thermodynamic model for the performance analysis of a Stirling engine prototype Miguel Torres García*, Elisa Carvajal Trujillo, José Antonio Vélez Godiño, David Sánchez Martínez University of Seville-Thermal Power Group - GMTS Escuela Técnica Superior de Ingenieros Industriales Camino de los descubrimientos s/n 41092 SEVILLA (SPAIN) e-mail: [email protected] KEYWORDS Stirling engine, combustion model Abstrac The scope of the study developed by the authors consists in comparing the results of simulations generated from different thermodynamic models of Stirling engines, characterizing both instantaneous and indicated operative parameters. The elaboration of this study aims to develop a tool to guide the decision-making process regarding the optimization of both performance and reliability of developing Stirling engines, such as the 3 kW GENOA 03 unit, on which this work focuses. Initially, the authors proceed to characterize the behaviour of the aforementioned engine using two different approaches: firstly, an ideal isothermal model is used, the simplest of those available; proceeding later to the analysis by means of an ideal adiabatic model, more complex than the first one. Since some of the results obtained with the referred ideal models are far from the expected actual ones, particularly in terms of thermal efficiency, the authors propose a set of modifications to the ideal adiabatic model. These modifications, mainly related to both heat transfer and fluid friction phenomena, are intended to overcome the limitations derived from the idealization of the engine working cycle and are expected to generate results closer to the actual behaviour of the Stirling engine, despite the increase in the complexity related to the modelling and simulation processes derived from those.