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.

First and Second Law Analyses of a Spark-Ignition Engine Using Either Isooctane or Hydrogen: An Initial Assessment

2006 ◽  
Author(s):  
Jerald A. Caton
Keyword(s):  
Nitric Oxide ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Performance Metrics ◽  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Second Law ◽  
Cycle Simulation ◽  
Nitric Oxide Emissions

The use of either hydrogen or isooctane for a spark-ignition engine was examined using a thermodynamic cycle simulation including the second law of thermodynamics. The engine studied was a 5.7 liter, automotive engine operating from idle to wide open throttle. The hydrogen or isooctane was assumed premixed with the air. Two features of hydrogen combustion that were included in the study were the higher flame speeds (shorter burn durations) and the wider lean flammability limits (lean equivalence ratios). Three cases were considered for the use of hydrogen: (1) standard burn duration and an equivalence ratio of 1.0, (2) a shorter burn duration and an equivalence ratio of 1.0, and (3) a shorter burn duration and variable, lean equivalence ratios. The results included thermal efficiencies, other performance metrics, second law parameters, and nitric oxide emissions. In general, for the cases with an equivalence of 1.0, the brake thermal efficiency was slightly lower for the hydrogen cases due to the higher temperatures and higher heat losses. For the variable, lean equivalence ratio cases, the thermal efficiency was higher for the hydrogen case relative to the isooctane case. Due to the higher temperatures, the hydrogen cases had over 50% higher nitric oxide emissions compared to the isooctane case at the base conditions. In addition, the second law analyses indicated that the destruction of availability during the combustion process was lower for the base hydrogen case (11.2%) relative to the isooctane case (21.1%).

A Multiple-Zone Cycle Simulation for Spark-Ignition Engines: Thermodynamic Details

2001 ◽  
Author(s):  
Jerald A. Caton
Keyword(s):  
Combustion Process ◽  
Load Condition ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Engine Operation ◽  
Part Load ◽  
Cycle Simulation ◽  
The Individual

Abstract A thermodynamic cycle simulation was developed for a spark-ignition engine which included the use of multiple zones for the combustion process. This simulation was used to complete analyses for a commercial, spark-ignition V-8 engine operating at a part load condition. Specifically, the engine possessed a compression ratio of 8.1:1, and had a bore and stroke of 101.6 and 88.4 mm, respectively. A part load operating condition at 1400 rpm with an equivalence ratio of 1.0 was examined. Results were obtained for overall engine performance, for detailed in-cylinder events, and for the thermodynamics of the individual processes. In particular, the characteristics of the engine operation with respect to the combustion process were examined. Implications of the multiple zones formulation for the combustion process are described.

Multidimensional Modeling of Premixed Turbulent Combustion: Modeling and Testing of a Small Spark-Ignition Engine

2001 ◽  
Author(s):  
Gustavo Fontana ◽  
Enzo Galloni ◽  
Elio Jannelli
Keyword(s):  
Turbulent Combustion ◽  
Combustion Process ◽  
Spark Ignition ◽  
Measured Data ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Engine Operation ◽  
Premixed Turbulent Combustion ◽  
Combustion Models ◽  
Good Reproduction

Abstract Combustion models, used in spark-ignition engine modeling, are reviewed. Different approaches for representing the main combustion features are reported. Limitations in simulating such a complex phenomenon as turbulent combustion in engines are highlighted as well. In order to compare different combustion models, the multidimensional program KIVA-3V has been used. The behavior of an actual spark-ignition engine has been investigated. In particular, simulation results, using simple chemical kinetics and mixing-controlled models, are compared. The results obtained, compared to measured data, confirm that different combustion models can lead to a satisfactory prediction of engine performances. But, in many cases, these models require experimental data for determining the model characteristic constants. A hybrid combustion model is proposed. It is able to provide a good reproduction of engine combustion process and, in particular, the model seems to be less sensitive to the engine operation. The computation results are compared to the measured data.

Utilizing a Cycle Simulation to Examine the Use of EGR for a Spark-Ignition Engine Including the Second Law of Thermodynamics

2006 ◽  
Author(s):  
Jerald A. Caton
Keyword(s):  
Combustion Process ◽  
Second Law Of Thermodynamics ◽  
Thermodynamic Cycle ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Second Law ◽  
Base Case ◽  
Nitric Oxides ◽  
Automotive Engine ◽  
Cycle Simulation

The use of exhaust gas recirculation (EGR) for a spark-ignition engine was examined using a thermodynamic cycle simulation including the second law of thermodynamics. Both a cooled and an adiabatic EGR configuration were considered. The engine was a 5.7 liter, automotive engine operating from idle to wide open throttle, and up to 6000 rpm. First, the reduction of nitric oxides is quantified for the base case condition (bmep = 325 kPa, 1400 rpm, φ = 1.0 and MBT timing). Over 90% reduction of nitric oxides is obtained with about 18% EGR for the cooled configuration, and with about 26% EGR for the adiabatic configuration. For constant load and speed, the thermal efficiencies increase with increasing EGR for both configurations, and the results show that this increase is mainly due to decreasing pumping losses and decreasing heat losses. In addition, results from the second law of thermodynamics indicated an increase in the destruction of availability (exergy) during the combustion process as EGR levels increase for both configurations. The major reason for this increase in the destruction of availability was the decrease in the combustion temperatures. Complete results for the availability destruction are provided for both configurations.

A Turbocharged, Spark-Ignition Engine: Results From an Engine Cycle Simulation Including the Second Law of Thermodynamics

2009 ◽  
Author(s):  
Vaibhav J. Lawand ◽  
Jerald A. Caton
Keyword(s):  
Combustion Process ◽  
Engine Performance ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Second Law ◽  
Base Case ◽  
Mixing Processes ◽  
Automotive Engine ◽  
Cycle Simulation

The use of turbocharging systems for spark-ignition engines has seen increased interest in recent years due to the importance of fuel efficiency, and in some cases, increased performance. An example of a possible strategy is to use a smaller displacement engine with turbocharging rather than a larger engine without turbocharging. To better understand the tradeoffs and the fundamental aspects of a turbocharged engine, this investigation is aimed at determining the energy and exergy quantities for a range of operating conditions for a spark-ignition engine. A 3.8 liter automotive engine with a turbocharger and intercooler was selected for this study. Various engine performance and other output parameters were determined as functions of engine speed and load. For the base case (2000 rpm and a bmep of 1200 kPa), the bsfc was about 240 g/kW-h. At these conditions, the second law analysis indicated that the original fuel exergy was distributed as follows: 34.7% was delivered as indicated work, 16.9% was moved via heat transfer to the cylinder walls, 23.0% exited with the exhaust gases, 20.6% was destroyed during the combustion process, 2.5% was destroyed due to inlet mixing processes, and 1.9% was destroyed due to the exhaust processes. The turbocharger components including the intercooler were responsible for less than 1.0% of the fuel exergy destruction or transfer.

scholarly journals Numerical Study of Engine Performance and Emissions for Port Injection of Ammonia into a Gasoline\Ethanol Dual-Fuel Spark Ignition Engine

2021 ◽  
Vol 11 (4) ◽  
pp. 1441
Author(s):  
Farhad Salek ◽  
Meisam Babaie ◽  
Amin Shakeri ◽  
Seyed Vahid Hosseini ◽  
Timothy Bodisco ◽  
...  
Keyword(s):  
Numerical Study ◽  
Combustion Process ◽  
Engine Performance ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Dual Fuel ◽  
Spark Ignition Engines ◽  
Performance And Emissions ◽  
Hc Emissions

This study aims to investigate the effect of the port injection of ammonia on performance, knock and NOx emission across a range of engine speeds in a gasoline/ethanol dual-fuel engine. An experimentally validated numerical model of a naturally aspirated spark-ignition (SI) engine was developed in AVL BOOST for the purpose of this investigation. The vibe two zone combustion model, which is widely used for the mathematical modeling of spark-ignition engines is employed for the numerical analysis of the combustion process. A significant reduction of ~50% in NOx emissions was observed across the engine speed range. However, the port injection of ammonia imposed some negative impacts on engine equivalent BSFC, CO and HC emissions, increasing these parameters by 3%, 30% and 21%, respectively, at the 10% ammonia injection ratio. Additionally, the minimum octane number of primary fuel required to prevent knock was reduced by up to 3.6% by adding ammonia between 5 and 10%. All in all, the injection of ammonia inside a bio-fueled engine could make it robust and produce less NOx, while having some undesirable effects on BSFC, CO and HC emissions.

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.

scholarly journals Efficiency characteristics of a new quasi-constant volume combustion spark ignition engine

2013 ◽  
Vol 17 (1) ◽  
pp. 119-133 ◽  
Author(s):  
Jovan Doric ◽  
Ivan Klinar
Keyword(s):  
Engine Speed ◽  
Combustion Process ◽  
Spark Ignition ◽  
Constant Volume ◽  
Spark Ignition Engine ◽  
Si Engine ◽  
Piston Mechanism ◽  
Si Engines ◽  
Ic Engines ◽  
Engine Concept

A zero dimensional model has been used to investigate the combustion performance of a four cylinder petrol engine with unconventional piston motion. The main feature of this new spark ignition (SI) engine concept is the realization of quasi-constant volume (QCV) during combustion process. Presented mechanism is designed to obtain a specific motion law which provides better fuel consumption of internal combustion (IC) engines. These advantages over standard engine are achieved through synthesis of unconventional piston mechanism. The numerical calculation was performed for several cases of different piston mechanism parameters, compression ratio and engine speed. Calculated efficiency and power diagrams are plotted and compared with performance of ordinary SI engine. The results show that combustion during quasi-constant volume has significant impact on improvement of efficiency. The main aim of this paper is to find a proper kinematics parameter of unconventional piston mechanism for most efficient heat addition in SI engines.

A Numerical Simulation of Analysis of Backfiring Phenomena in a Hydrogen-Fueled Spark Ignition Engine

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
K. A. Subramanian ◽  
B. L. Salvi
Keyword(s):  
Greenhouse Gas Emission ◽  
Hot Spot ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Intake Manifold ◽  
Injection Timing ◽  
Si Engine ◽  
Engine Operation ◽  
Study Results ◽  
Residual Gas

Hydrogen utilization in spark ignition (SI) engines could reduce urban pollution including particulate matter as well as greenhouse gas emission. However, backfiring, which is an undesirable combustion process of intake charge in hydrogen-fueled SI engine with manifold-based injection, is one of the major technical issues in view of safety of engine operation. Backfiring occurs generally during suction stroke as the hydrogen–air charge interacts with residual gas, resulting in flame growth and propagation toward upstream of engine's intake manifold, resulting in stalling of engine operation and high risk of safety. This work is aimed at analysis of backfiring in a hydrogen-fueled SI engine. The results indicate that backfiring is mainly function of residual gas temperature, start of hydrogen injection timing, and equivalence ratio. Any hot-spot present in the cylinder would act as ignition source resulting in more chances of backfiring. In addition to this, computational fluid dynamics (CFD) analysis was carried out in order to assess flow characteristics of hydrogen and air during suction stroke in intake manifold. Furthermore, numerical analysis of intake charge velocity, flame speed (deflagration), and flame propagation (backfiring) toward upstream of intake manifold was also carried out. Some notable points of backfiring control strategy including exhaust gas recirculation (EGR) and retarded (late) hydrogen injection timing are emerged from this study for minimizing chance of backfiring. This study results are useful for development of dedicated SI engine for hydrogen fuel in the aspects of elimination of backfiring.

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