Assessment of possible use of the ionization signal for the combustion process diagnostics in a spark ignition combustion engine powered by natural gas

This research investigated the combustion process of an AVL Model LEF/Volvo 5312 single cylinder engine configured to simulate the operation of a heavy-duty spark ignition (SI) natural gas (NG) engine operated on stoichiometric mixture. The factors affecting the combustion process that were examined include intake pressure, spark timing (ST), and the addition of diluents including nitrogen (N2) and carbon dioxide (CO2) to the NG to simulate low British thermal unit (BTU) gases. The mixing of diluents with NG is able to slow down the flame propagation speed, suppress the onset of knock, and allow the engine to operate on higher boost pressure for higher power output. The addition of CO2 was more effective than N2 in suppressing the onset of knock and slowing down the flame propagation speed due to its high heat capacity. Boosting intake pressure significantly increased the heat release rate (HRR) evaluated on J/°CA basis which represents the rate of mass of fuel burning. However, its impact on the normalized HRR evaluated on %/°CA basis, representing the flame propagation rate, was relatively mild. Boosting the intake pressure from 1.0 to 1.8 bar without adding diluents increased the peak HRR to 1.96 times of that observed at 1.0 bar. The increase was due to the burning of more fuel (about 1.8 times), and the 12.9% increase in the normalized HRR. The latter was due to the shortened combustion duration from 23.6 to 18.2 °CA, a 22.9% reduction. The presence of 40% CO2 or N2 in their mixture with NG increased the peak cylinder pressure (PCP) limited brake mean effective pressure (BMEP) from 17.2 to about 20.2 bar. The combustion process of a turbocharged SI NG engine can be approximated by referring to the HRR measured under a naturally aspirated condition. This makes it convenient for researchers to numerically simulate the combustion process and the onset of knock of turbocharged SI NG engines using combustion process data measured under naturally aspirated conditions as a reference.

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Relations between ion signal and flame propagation in cylinder of a rapid compression machine

Combustion Engines ◽

10.19206/ce-2019-444 ◽

2019 ◽

Vol 179 (4) ◽

pp. 264-268

Author(s):

Łukasz FIEDKIEWICZ ◽

Ireneusz PIELECHA

Keyword(s):

Combustion Engine ◽

Combustion Process ◽

Coefficient Of Determination ◽

Rapid Compression Machine ◽

Process Diagnosis ◽

Gaseous Fuels ◽

Ionization Signal ◽

Flame Development ◽

Combustion Phase ◽

Rapid Compression

Internal combustion engine diagnostics using traditional methods of cylinder pressure signal processing limits the amount of information available about the combustion process. It is necessary to conduct research in order to obtain more precise information – increasing the combustion process diagnosis potential. One such suggestion is the use of an ionization signal and an attempt to link it to the flame development during combustion of gaseous fuels. The article attempts to identify such a relationship using a rapid compression machine due to optical access it provides to the combustion chamber. As a result of the research, the relationships between the ionization voltage (chemical and thermal) of the first combustion phase and the corresponding flame development rates were determined. A relatively high coefficient of determination value was obtained for both relations, which indicates the possibility of obtaining diagnostic information about the combustion process from the ionization signal.

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Improved Thermodynamic Model for Lean Natural Gas Spark Ignition in a Diesel Engine Using a Triple Wiebe Function

Journal of Energy Resources Technology ◽

10.1115/1.4045534 ◽

2019 ◽

Vol 142 (6) ◽

Cited By ~ 3

Author(s):

Jinlong Liu ◽

Cosmin Emil Dumitrescu

Keyword(s):

Natural Gas ◽

Diesel Engines ◽

Mass Fraction ◽

Internal Combustion Engines ◽

Combustion Process ◽

Spark Ignition ◽

High Energy ◽

Multi Stage ◽

Stage Combustion ◽

Wiebe Function

Abstract The use of natural gas (NG) in heavy-duty internal combustion engines can reduce the dependence on petroleum fuels and greenhouse gas emissions. Diesel engines can convert to NG spark ignition (SI) by installing a high-energy ignition system and a gas injector. The diesel combustion chamber affects the flow inside the cylinder, so some existing SI combustion models will not accurately describe the operation of converted diesels. For example, the single Wiebe function has difficulties in correctly describing the mass fraction burn (MFB) throughout the combustion process. This study used experiments from a 2L single-cylinder research engine converted to port fuel injection NG SI and operated with methane at 1300 rpm and equivalence ratio 0.8 (6.2 bars IMEP) to compare the standard Wiebe function with a triple Wiebe function. Results indicated that lean-burn engine operation at an advanced spark timing produced three peaks in the heat release rate, suggesting a multi-stage combustion process. A “best goodness-of-fit” approach determined the values of the key parameters in the zero-dimensional Wiebe function model. The triple Wiebe function described the mass fraction burn and combustion phasing more accurately compared with the single Wiebe function. Moreover, it provided the duration and phasing of each individual burning stage that can then characterize the combustion in such converted diesel engines. This suggests that a multiple Wiebe function combustion model would effectively assist in analyzing such a multi-stage combustion process, which is important for engine optimization and development.

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Two-Stage Lean-Burn Combustion Inside a Natural-Gas Spark-Ignition Engine With a Bowl-in-Piston Chamber

ASME 2019 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2019-7181 ◽

2019 ◽

Author(s):

Jinlong Liu ◽

Cosmin E. Dumitrescu

Keyword(s):

Natural Gas ◽

Combustion Chamber ◽

Combustion Process ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Intake Manifold ◽

Hydrocarbon Emissions ◽

Fuel Injector ◽

Unburned Hydrocarbon ◽

Piston Chamber

Abstract The conversion of existing diesel engines to spark ignition (SI) operation by adding a low-pressure injector in the intake manifold for fuel delivery and replacing the original high-pressure fuel injector with a spark plug to initiate and control the combustion process can reduce U.S. dependence on petroleum imports and increase natural gas (NG) applications in heavy-duty transportation sectors. Since the conventional diesel combustion chamber (i.e., flat-head-and-bowl-in-piston-chamber) creates high turbulence, the converted NG SI engine can operate leaner with stable and repeatable combustion process. However, existing literatures point to a long late-combustion duration and increased unburned hydrocarbon emissions in such retrofitted engines that maintained the original combustion chamber. Consequently, the main objective of this paper was to report recent findings of NG combustion characteristics inside a bowl-in-piston combustion chamber that will add to the general understanding of the phenomena. The new results indicated that the premixed NG burn inside the bowl-in-piston combustion chamber will separate into a bowl-burn and a squish-burn processes in terms of burning location and timing. The slow burning event in the squish region explains the low slope of the burn rate towards the end of combustion in existing studies (hence the longer late-combustion period). In addition, the less-favorable conditions for the combustion in the squish region explained the increased carbon monoxide and unburned hydrocarbon emissions.

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NONPERIODIC OSCILLATIONS OF PRESSURE IN A SPARK IGNITION COMBUSTION ENGINE

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127404010084 ◽

2004 ◽

Vol 14 (05) ◽

pp. 1801-1806 ◽

Cited By ~ 22

Author(s):

M. WENDEKER ◽

G. LITAK ◽

J. CZARNIGOWSKI ◽

K. SZABELSKI

Keyword(s):

Time Series ◽

Combustion Engine ◽

Rotational Velocity ◽

Combustion Process ◽

Recurrence Plot ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Stochastic Noise ◽

Experimental Time Series ◽

Multidimensional Process

We report our results on nonperiodic experimental time series of pressure in a spark ignition engine. The experiments were performed for a low rotational velocity of a crankshaft and a relatively large spark advance angle. We show that the combustion process has many chaotic features. Surprisingly, the reconstructed attractor has a characteristic butterfly shape similar to a chaotic attractor of Lorentz type. The suitable recurrence plot shows that the dynamics of the combustion is a nonlinear multidimensional process mediated by stochastic noise.

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Characterization of the combustion process and cycle-to-cycle variations in a spark ignition engine fuelled with natural gas/hydrogen mixtures

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2015.10.082 ◽

2016 ◽

Vol 41 (3) ◽

pp. 2064-2074 ◽

Cited By ~ 28

Author(s):

M. Reyes ◽

F.V. Tinaut ◽

A. Melgar ◽

A. Pérez

Keyword(s):

Natural Gas ◽

Combustion Process ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Hydrogen Mixtures

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A Parametric Model for Ionization Current in a Four Stroke SI Engine

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.3023119 ◽

2009 ◽

Vol 131 (2) ◽

Cited By ~ 7

Author(s):

Ingemar Andersson ◽

Lars Eriksson

Keyword(s):

Internal Combustion Engine ◽

Combustion Engine ◽

Current Model ◽

Combustion Process ◽

Internal Combustion ◽

Current Status ◽

Cylinder Pressure ◽

Ionization Current ◽

Ionization Signal ◽

Combustion Properties

A model for the thermal part of an ionization signal is presented that connects the ionization current to cylinder pressure and temperature in a spark ignited internal combustion engine. One strength of the model is that, after calibration, it has only two free parameters: burn angle and initial kernel temperature. By fitting the model to a measured ionization signal, it is possible to estimate both cylinder pressure and temperature, where the pressure is estimated with good accuracy. The model approach is validated on engine data. Cylinder pressure and ionization current data were collected on a Saab four-cylinder spark ignited engine for a variation in ignition timing and air-fuel ratio. The main result is that the parametrized ionization current model can be used to estimating combustion properties as pressure, temperature, and content of nitric oxides based on measured ionization currents. The current status of the model is suitable for off-line analysis of ionization currents and cylinder pressure. This ionization current model not only describes the connection between the ionization current and the combustion process, but also offers new possibilities for engine management system to control the internal combustion engine.

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On the use of artificial neural networks to model the performance and emissions of a heavy-duty natural gas spark ignition engine

International Journal of Engine Research ◽

10.1177/14680874211034409 ◽

2021 ◽

pp. 146808742110344

Author(s):

Qiao Huang ◽

Jinlong Liu ◽

Christopher Ulishney ◽

Cosmin E Dumitrescu

Keyword(s):

Neural Network ◽

Natural Gas ◽

Combustion Process ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Heavy Duty ◽

Network Algorithm ◽

Performance And Emissions ◽

Neural Network Algorithm ◽

Artificial Neural

The use of computational models for internal combustion engine development is ubiquitous. Numerical simulations using simpler to complex physical models can predict engine’s performance and emissions, but they require large computational capabilities. By comparison, statistical methodologies are more economical tools in terms of time and resources. This paper investigated the use of an artificial neural network algorithm to simulate the nonlinear combustion process inside the cylinder. Three engine control variables (i.e. spark timing, mixture equivalence ratio, and engine speed) were set as the model inputs. Outputs included peak cylinder pressure and its location, maximum pressure rise rate, indicated mean effective pressure, ignition lag, combustion phasing, burn duration, exhaust temperature, and engine-out emissions (i.e. nitrogen oxides, carbon monoxide, and unburned hydrocarbons). Eighty percent of the experimental data from a heavy-duty natural gas spark ignition engine were utilized to train the model. The perceptions accurately learned the combustion characteristics and predicted engine responses with acceptable errors, evidenced by close-to-unity coefficient of determination and close-to-zero root-mean-square error. Moreover, the regressors captured the effect of key operating variables on the engine response, suggesting the well-trained models successfully identified the complex relationships and can help assist engine analysis. Overall, the neural network algorithm was appropriate for the application investigated in this study.

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CFD 3D Analysis of Charge Motion and Combustion in a Spark-Ignition Internal Combustion Engine under Close-to-Idle Condition

E3S Web of Conferences ◽

10.1051/e3sconf/202019706011 ◽

2020 ◽

Vol 197 ◽

pp. 06011

Author(s):

Roberto Bozza ◽

Vincenzo De Bellis ◽

Stefano Fantoni ◽

Donato Colangelo

Keyword(s):

Combustion Engine ◽

Early Stage ◽

Local Level ◽

Combustion Process ◽

Spark Ignition ◽

Operating Conditions ◽

Transport Sector ◽

3D Analysis ◽

Charge Motion ◽

Throttle Valve

The increasingly stringent limitations on noxious missions of transport sector highly affect the development of new engines. The operating conditions of the engine at low-load and idle play a relevant role along the regulatory homologation cycles, contributing to overall emissions. In this work, the effectiveness of some solutions to improve the behaviour under close-to-idle operation of a Spark-Ignition motorcycle engine are compared by 3D CFD analyses. Specifically, the effects of two designs of the intake port and of the opening direction of the throttle valve, either clockwise or counterclockwise, are investigated. Multi-cycle simulations are carried out, under motored and fired conditions, for a single close-to-idle operating point. The various designs are compared in terms of capability to generate a stable tumble vortex during the intake phase and to produce an adequate turbulence level at the beginning of the combustion process. The analyses revealed that a clockwise throttle opening can produce enhanced turbulence levels at the end of the compression stroke, especially in a close-to-spark region (increase of about 5% and 27 % at the TDC at a global and local level, respectively, compared to the base configuration). Additional limited improvements are obtained with the high tumbling design, where, however, a penalty on the maximum power output could emerge. The flow and turbulence motion differences among the tested geometries reflect on combustion development in its early stage, and on its degree of completeness at the exhaust valve opening. A clockwise opening of the throttle valve leads to an increase of the mass fraction burned of 5 percent points, compared to the base configuration.

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Indicated Mean Effective Pressure Oscillations in a Natural Gas Combustion Engine

Zeitschrift für Naturforschung A ◽

10.1515/zna-2009-5-614 ◽

2009 ◽

Vol 64 (5-6) ◽

pp. 393-398 ◽

Cited By ~ 5

Author(s):

Grzegorz Litak ◽

Michał Gęca ◽

Bao-Feng Yao ◽

Guo-Xiu Li

Keyword(s):

Natural Gas ◽

Combustion Engine ◽

Combustion Process ◽

Spark Ignition Engine ◽

Effective Pressure ◽

Gas Combustion ◽

Indicated Mean Effective Pressure ◽

Natural Gas Combustion ◽

Measured Pressure ◽

Lean Conditions

Fluctuations in a combustion process of natural gas in the internal spark ignition engine have been investigated. We measured pressure of the cyclic combustion and expressed its cyclic oscillations in terms of indicated mean effective pressure per cycle. By applying the statistical and multifractal analysis to the corresponding time series we show the considerable changes in engine dynamics for a different equivalence ratio decreases from 0.781 to very lean conditions.

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