Thermodynamic Analysis of SI Engine Operation on Variable Composition Biogas-Hydrogen Blends Using a Quasi-Dimensional, Multi-Zone Combustion Model

2009 ◽  
Vol 2 (1) ◽  
pp. 880-910 ◽  
Author(s):  
C.D. Rakopoulos ◽  
C.N. Michos ◽  
E.G. Giakoumis
Keyword(s):  
Thermodynamic Analysis ◽  
Variable Composition ◽  
Combustion Model ◽  
Si Engine ◽  
Engine Operation

Studying the effects of hydrogen addition on the second-law balance of a biogas-fuelled spark ignition engine by use of a quasi-dimensional multi-zone combustion model

2008 ◽  
Vol 222 (11) ◽  
pp. 2249-2268 ◽  
Author(s):  
C D Rakopoulos ◽  
C N Michos ◽  
E G Giakoumis
Keyword(s):  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Second Law ◽  
Si Engine ◽  
Engine Operation ◽  
Hydrogen Addition ◽  
Cycle Simulation ◽  
Hydrogen Enrichment

Although a first-law analysis can show the improvement that hydrogen addition impacts on the performance of a biogas-fuelled spark-ignition (SI) engine, additional benefits can be revealed when the second law of thermodynamics is brought into perspective. It is theoretically expected that hydrogen enrichment in biogas can increase the second-law efficiency of engine operation by reducing the combustion-generated irreversibilities, because of the fundamental differences in the mechanism of entropy generation between hydrogen and traditional hydrocarbon combustion. In this study, an experimentally validated closed-cycle simulation code, incorporating a quasi-dimensional multi-zone combustion model that is based on the combination of turbulent entrainment theory and flame stretch concepts for the prediction of burning rates, is further extended to include second-law analysis for the purpose of quantifying the respective improvements. The analysis is applied for a single-cylinder homogeneous charge SI engine, fuelled with biogas—hydrogen blends, with up to 15 vol% hydrogen in the fuel mixture, when operated at 1500r/min, wide-open throttle, fuel-to-air equivalence ratio of 0.9, and ignition timing of 20° crank angle before top dead centre. Among the major findings derived from the second-law balance during the closed part of the engine cycle is the increase in the second-law efficiency from 40.85 per cent to 42.41 per cent with hydrogen addition, accompanied by a simultaneous decrease in the combustion irreversibilities from 18.25 per cent to 17.18 per cent of the total availability of the charge at inlet valve closing. It is also illustrated how both the increase in the combustion temperatures and the decrease in the combustion duration with increasing hydrogen content result in a reduction in the combustion irreversibilities. The degree of thermodynamic perfection of the combustion process from the second-law point of view is quantified by using two (differently defined) combustion exergetic efficiencies, whose maximum values during the combustion process increase with hydrogen enrichment from 49.70 per cent to 53.45 per cent and from 86.01 per cent to 87.33 per cent, respectively.

scholarly journals Evaluation of the Predictive Capabilities of a Phenomenological Combustion Model for Natural Gas SI Engine

2017 ◽  
Vol 15 (2) ◽  
pp. 37-48 ◽  
Author(s):  
Rastislav Toman ◽  
Jan Macek
Keyword(s):  
Natural Gas ◽  
Laminar Flame ◽  
Computational Effort ◽  
Combustion Model ◽  
Charge Motion ◽  
Si Engine ◽  
Engine Operation ◽  
Calibration Methods ◽  
Sensitivity Studies ◽  
Cylinder Flow

Abstract The current study evaluates the predictive capabilities of a new phenomenological combustion model, available as a part of the GT-Suite software package. It is comprised of two main sub-models: 0D model of in-cylinder flow and turbulence, and turbulent SI combustion model. The 0D in-cylinder flow model (EngCylFlow) uses a combined K-k-ε kinetic energy cascade approach to predict the evolution of the in-cylinder charge motion and turbulence, where K and k are the mean and turbulent kinetic energies, and ε is the turbulent dissipation rate. The subsequent turbulent combustion model (EngCylCombSITurb) gives the in-cylinder burn rate; based on the calculation of flame speeds and flame kernel development. This phenomenological approach reduces significantly the overall computational effort compared to the 3D-CFD, thus allowing the computation of full engine operating map and the vehicle driving cycles. Model was calibrated using a full map measurement from a turbocharged natural gas SI engine, with swirl intake ports. Sensitivity studies on different calibration methods, and laminar flame speed sub-models were conducted. Validation process for both the calibration and sensitivity studies was concerning the in-cylinder pressure traces and burn rates for several engine operation points achieving good overall results.

Thermodynamic Analysis of a Multi-Fueled Single Cylinder SI Engine

2011 ◽  
Author(s):  
M. Z. Haq ◽  
M. R. Mohiuddin
Keyword(s):  
Thermodynamic Analysis ◽  
Chemical Properties ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Si Engine ◽  
Gaseous Species ◽  
Single Cylinder ◽  
Engine Cylinder ◽  
Si Engines

The paper presents a thermodynamic analysis of a single cylinder four-stroke spark-ignition (SI) engine fuelled by four fuels namely iso-octane, methane, methanol and hydrogen. In SI engines, due to phenomena like ignition delay and finite flame speed manifested by the fuels, the heat addition process is not instantaneous, and hence ‘Weibe function’ is used to address the realistic heat release scenario of the engine. Empirical correlations are used to predict the heat loss from the engine cylinder. Physical states and chemical properties of gaseous species present inside the cylinder are determined using first and second law of thermodynamics, chemical kinetics, JANAF thermodynamic data-base and NASA polynomials. The model is implemented in FORTRAN 95 using standard numerical routines and some simulation results are validated against data available in literature. The second law of thermodynamics is applied to estimate the change of exergy i.e. the work potential or quality of the in-cylinder mixture undergoing various phases to complete the cycle. Results indicate that, around 4 to 24% of exergy initially possessed by the in-cylinder mixture is reduced during combustion and about 26 to 42% is left unused and exhausted to the atmosphere.

EGR Effects on Boosted SI Engine Operation and Knock Integral Correlation

2012 ◽  
Vol 5 (2) ◽  
pp. 547-559 ◽  
Author(s):  
Bjoern Hoepke ◽  
Stefan Jannsen ◽  
Emmanuel Kasseris ◽  
Wai K. Cheng
Keyword(s):  
Si Engine ◽  
Engine Operation

A Control-Oriented Reaction-Based SI Engine Combustion Model

2018 ◽  
Author(s):  
Ruixue C. Li ◽  
Guoming G. Zhu
Keyword(s):  
Chemical Reaction ◽  
Mass Fraction ◽  
Combustion Process ◽  
Combustion Model ◽  
Spark Ignition Engines ◽  
Si Engine ◽  
Chemical Reaction Mechanism ◽  
Engine Combustion ◽  
Rate Of Heat Release ◽  
Mass And Heat Transfer

This paper proposes a control-oriented chemical reaction-based two-zone combustion model designed to accurately describe the combustion process and thermal performance for spark-ignition engines. The combustion chamber is assumed to be divided into two zones: reaction and unburned zones, where the chemical reaction takes place in the reaction zone and the unburned zone contains all the unburned mixture. In contrast to the empirical pre-determined Wiebe-function-based combustion model, an ideal two-step chemical reaction mechanism is used to reliably model the detailed combustion process such as mass-fraction-burned (MFB) and rate of heat release. The interaction between two zones includes mass and heat transfer at the zone interface to have a smooth combustion process. This control-oriented model is extensively calibrated based on the experimental data to demonstrate its capability of predicting the combustion process and thermodynamic states of the in-cylinder mixture.

scholarly journals Experimental Investigation of Using Ethanol-Gasoline in Spark Ignition Engine

2018 ◽  
Vol 21 (3) ◽  
pp. 368-373
Author(s):  
Kadhim Fadhil Nasir
Keyword(s):  
Spark Ignition Engine ◽  
Brake Specific Fuel Consumption ◽  
Si Engine ◽  
Pure Ethanol ◽  
Engine Operation ◽  
Brake Thermal Efficiency ◽  
Brake Power ◽  
Operation Parameter ◽  
Ethanol Addition ◽  
And Performance

The consequence of mixing pure ethanol with gasoline on the pollution and performance of SI engine are investigated experimentally in the existent study. The SI engine that employed in the experiment is a single cylinder four stroke. Analysis is carried out for engine operation parameter, CO2, CO and unburned HC productions. The measurements are recorded for several engine speeds from 1500 – 3000 rpm with load and ethanol addition of (0E, 10E, 20E, 30E, 40E, 50E,). The results displayed increasing in brake power, and brake thermal efficiency while the brake specific fuel consumption decreases when the ethanol- gasoline blends fuel increases. Also it was found that CO, HC, and CO2 concentrations decrease when the ethanol- gasoline increases. The best results obtained in the study is for the blend of E-50.

Optimization of SI Engine Cycle with Variable Composition and Specific Heat

2020 ◽  
pp. 261-269
Author(s):  
Akhil Sukumaran ◽  
P. Anu Nair ◽  
S. Sourabh Gopal ◽  
P. S. Sabin ◽  
Jithu M. Suredran ◽  
...  
Keyword(s):  
Specific Heat ◽  
Variable Composition ◽  
Si Engine ◽  
Engine Cycle

Diesel engine control optimization for transient operation with lean/rich switches

2003 ◽  
Vol 4 (3) ◽  
pp. 219-231 ◽  
Author(s):  
N. P. Kyrtatos ◽  
E. I. Tzanos ◽  
C. I. Papadopoulos
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Optimization Procedure ◽  
Combustion Model ◽  
Transient Operation ◽  
Simulation Code ◽  
Engine Operation ◽  
Control Optimization ◽  
Management Schemes ◽  
Engine Components

Transient operation of a direct injection heavy duty (DI HD) diesel engine equipped with an NOx storage catalyst (NSC) was simulated using a ‘virtual powerplant’ simulation code with a zero-dimensional multizone combustion model. For the regeneration of the NSC the engine is required to work with lean/rich operation switches, which necessitates advanced engine management schemes for the fuelling, throttle and turbocharger wastegate. An optimization procedure, using the simulation model, resulted in a proposed schedule for the control of the various engine components involved in such engine operation.

A Control-Oriented Jet Ignition Combustion Model for an SI Engine

2015 ◽  
Author(s):  
Ruitao Song ◽  
Gerald Gentz ◽  
Guoming Zhu ◽  
Elisa Toulson ◽  
Harold Schock
Keyword(s):  
Combustion Chamber ◽  
Combustion Process ◽  
Turbulent Jets ◽  
Combustion Stability ◽  
Combustion Model ◽  
Combustion Chambers ◽  
Si Engine ◽  
Lean Operations ◽  
Combustion Processes ◽  
Hil Simulation

A turbulent jet ignition system of a spark ignited (SI) engine consists of pre-combustion and main-combustion chambers, where the combustion in the main-combustion chamber is initiated by turbulent jets of reacting products from the pre-combustion chamber. If the gas exchange and combustion processes are accurately controlled, the highly distributed ignition will enable very fast combustion and improve combustion stability under lean operations, which leads to high thermal efficiency, knock limit extension, and near zero NOx emissions. For model-based control, a precise combustion model is a necessity. This paper presents a control-oriented jet ignition combustion model, which is developed based on simplified fluid dynamics and thermodynamics, and implemented into a dSPACE based real-time hardware-in-the-loop (HIL) simulation environment. The two-zone combustion model is developed to simulate the combustion process in two combustion chambers. Correspondingly, the gas flowing through the orifices between two combustion chambers is divided into burned and unburned gases during the combustion process. The pressure traces measured from a rapid compression machine (RCM), equipped with a jet igniter, are used for initial model validation. The HIL simulation results show a good agreement with the experimental data.

scholarly journals Possibilities to identify engine combustion model parameters by analysis of the instantaneous crankshaft angular speed

2014 ◽  
Vol 18 (1) ◽  
pp. 97-112 ◽  
Author(s):  
Slobodan Popovic ◽  
Miroljub Tomic
Keyword(s):  
Combustion Process ◽  
Nonlinear Least Squares ◽  
Angular Speed ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Model Parameters ◽  
Si Engine ◽  
Engine Combustion ◽  
Novel Method ◽  
Engine Crankshaft

In this paper, novel method for obtaining information about combustion process in individual cylinders of a multi-cylinder Spark Ignition Engine based on instantaneous crankshaft angular velocity is presented. The method is based on robust box constrained Levenberg-Marquardt minimization of nonlinear Least Squares given for measured and simulated instantaneous crankshaft angular speed which is determined from the solution of the engine dynamics torque balance equation. Combination of in-house developed comprehensive Zero-Dimensional Two-Zone SI engine combustion model and analytical friction loss model in angular domain have been applied to provide sensitivity and error analysis regarding Wiebe combustion model parameters, heat transfer coefficient and compression ratio. The analysis is employed to evaluate the basic starting assumption and possibility to provide reliable combustion analysis based on instantaneous engine crankshaft angular speed.

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