Effects of H2 Addition to CNG Blends on Cycle-to-Cycle and Cylinder-to-Cylinder Combustion Variation in an SI Engine

2012 ◽  
Author(s):  
Mirko Baratta ◽  
Stefano d’Ambrosio ◽  
Daniela Misul ◽  
Ezio Spessa
Keyword(s):  
Diagnostic Tool ◽  
Combustion Process ◽  
Experimental Tests ◽  
Test Point ◽  
Pollutant Emissions ◽  
Engine Operation ◽  
Pressure Transducers ◽  
Rate Analysis ◽  
Spark Plug ◽  
Wide Range

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter CNG (compressed natural gas) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure and temperature at different locations on the engine intake and exhaust systems as well as ‘engine-out’ pollutant emissions have been measured. The signals correlated to the engine operation have been acquired by means of a National Instruments PXI-DAQ system and a home developed software. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a CAD procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads and relative air-fuel ratios (up to the lean operation). For stoichiometric operation, the addition of hydrogen to CNG has produced a bsfc reduction ranging between 2 to 7% and a bsTHC decrease up to the 40%. These benefits have appeared to be even higher for lean mixtures. Moreover, hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. As a matter of fact, hydrogen addition has generally resulted into extended operation up to RAFR = 1.8. Still, a discrepancy in the abovementioned conclusions was observed depending on the engine cylinder considered.

Effects of H2 Addition to Compressed Natural Gas Blends on Cycle-to-Cycle and Cylinder-to-Cylinder Combustion Variation in a Spark-Ignition Engine

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Mirko Baratta ◽  
Stefano d'Ambrosio ◽  
Daniela Misul ◽  
Ezio Spessa
Keyword(s):  
Natural Gas ◽  
Diagnostic Tool ◽  
Computer Aided Design ◽  
Combustion Process ◽  
Spark Ignition Engine ◽  
Pollutant Emissions ◽  
Engine Operation ◽  
Compressed Natural Gas ◽  
Spark Plug ◽  
Wide Range

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter compressed natural gas (CNG) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder, and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure, and temperature at different locations on the engine intake and exhaust systems as well as “engine-out” pollutant emissions have been measured. The signals related to engine operation have been acquired by means of a National Instruments PXI-DAQ system and software developed in house. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a computer-aided design (CAD) procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads, and relative air-fuel ratios (up to the lean operation limit (LOL)). For stoichiometric operation, the addition of hydrogen to CNG has produced a brake-specific fuel combustion (bsfc) reduction ranging between 2% and 7% and a brake-specific total unburned hydrocarbons (bsTHCs) decrease up to 40%. These benefits have appeared to be even higher for lean mixtures. Hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. Hydrogen addition has generally resulted in extended operation up to relative air-to-fuel ratio (RAFR) = 1.8. Still, the LOL consistently varies depending on the considered cylinder.

scholarly journals Performances of a Research CFR Octane Rating Unit Engine and Dacia Single Cylinder SI Engine Ignited by a LASER System

2019 ◽  
Vol 112 ◽  
pp. 01009
Author(s):  
Bogdan George Done ◽  
Ion Copae
Keyword(s):  
New Technologies ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Laser Medium ◽  
Si Engine ◽  
Engine Operation ◽  
Single Cylinder ◽  
Spark Plug ◽  
Octane Rating ◽  
Laser Spark

At this time, the severe legislation regarding the level limits of the waste and exhaust gases released by thermal engines and also the necessity of engines efficiency improvement boost the engine research domain to bring in front the use of new technologies that can be used to control the in-cylinder combustion process. Now, the new technologies is represented by LASER spark plug systems which can be successfully used at petrol engines. LASER spark plug technology can have many advantages for engine operation control, an ignition system that could provide improved combustion is the one using plasma generation and a Q-switched LASER that results in pulses with high MW power. The LASER spark plug device used in the current research was a LASER medium Nd:YAG/Cr4+:YAG ceramic structure made up of a 8.0-mm long, 1.0-at.% Nd:YAG ceramic, optically-bonded to a Cr4+:YAG c. It was developed and constructed similar to classical spark plug and could be assembled on a CFR Octane Rating Unit Engine as well as on a Dacia Single Cylinder SI Engine which led to several results among which: influences on in-cylinder pressure, combustion and pollutant emissions.

scholarly journals Fuel-to-air ratio control under short-circuit conditions through UEGO sensor signal analysis

2019 ◽  
Vol 21 (9) ◽  
pp. 1577-1583
Author(s):  
Carlos Guardiola ◽  
Benjamín Pla ◽  
Marcelo Real ◽  
Cyril Travaillard ◽  
Frederic Dambricourt
Keyword(s):  
Signal Analysis ◽  
Equivalence Ratio ◽  
Short Circuit ◽  
Experimental Tests ◽  
Pollutant Emissions ◽  
Frequency Content ◽  
Novel Approach ◽  
Wide Range ◽  
The Impact ◽  
Three Way Catalyst

The impact of short-circuit pulses on the after-treatment system of a spark-ignited engine must be taken into account to keep the fuel-to-air equivalence ratio within the three-way catalyst window, thereby reducing pollutant emissions. The fuel-to-air equivalence ratio overestimation that suffers the wide-range λ-sensor upstream three-way catalyst in the presence of short circuit is especially relevant. In this study, a novel approach to deal with the fuel-to-air equivalence ratio control under short-circuit conditions is introduced. Under this scope, this work proposes a strategy for the on-board correction of the aforementioned fuel-to-air equivalence ratio overestimation, by means of the information regarding short-circuit level that provides the frequency content of the λ-sensor at the engine frequency. Finally, the potential of this approach to minimize pollutant emissions, in particular the NO x penalty arisen as a consequence of running the engine under leaner conditions than expected, is assessed through experimental tests.

Humid Air NOx Reduction Effect on Liquid Fuel Combustion

2004 ◽  
Vol 126 (1) ◽  
pp. 69-74 ◽  
Author(s):  
A. G. Chen ◽  
Daniel J. Maloney ◽  
William H. Day
Keyword(s):  
Liquid Fuel ◽  
Nox Reduction ◽  
Flame Temperature ◽  
Substantial Reduction ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Humid Air ◽  
Wide Range ◽  
Reduction Of Nox ◽  
Reduction Effect

An experimental investigation was carried out at DOE NETL on the humid air combustion process using liquid fuel to determine the effects of humidity on pollutant emissions and flame stability. Tests were conducted at pressures of up to 100 psia (690 kPa), and a typical inlet air temperature of 860°F (733 K). The emissions and RMS pressures were documented for a relatively wide range of flame temperature from 2440-3090°F (1610–1970 K) with and without added humidity. The results show more than 90% reduction of NOx through 10% humidity addition to the compressed air compared with the dry case at the same flame temperature. The substantial reduction of NOx is due to a shift in the chemical mechanisms and cannot be explained by flame temperature reduction due to added moisture since the comparison was made for the same flame temperature.

scholarly journals Researches on Soot Filtration Process by Comparing Simulation and Experimental Tests

2021 ◽  
Vol 44 (4) ◽  
pp. 54-59
Author(s):  
Bogdan Manolin JURCHIȘ
Keyword(s):  
Particle Filter ◽  
Combustion Engine ◽  
Combustion Process ◽  
Engine Performance ◽  
Experimental Tests ◽  
Point Of View ◽  
Pollutant Emissions ◽  
Particulate Filter ◽  
The Creation ◽  
Two Stages

In this paper, the main objective of using numerical simulation was to highlight and analyse details that are very difficult to highlight through experimental tests. The development of the simulation model was also done for predictive purposes. In other words, after validation of the model, it can be used to estimate the filter load in other conditions than the experimental ones, respectively to evaluate how the particulate filter affects the operation of the internal combustion engine. In order to achieve the desired result, the creation of the model was done in two stages, the first stage was the creation of a model containing all the components of the engine, except the particle filter in order to identify the parameters of the combustion process and pollutant emissions - model validated on the basis of the indicated pressure curves, and the second stage was to complete the initial model with a particle filter and validate it from the point of view of the pressure drop, respectively of the engine performance, the aim was to obtain a trend, respectively values similar to the experimental ones.

Validation of a Directed Energy Ignition System on a Large-Bore Single Cylinder Gas-Fueled Engine

2020 ◽  
Author(s):  
Forrest Pommier ◽  
David Lepley ◽  
Greg Beshouri ◽  
Timothy Jacobs
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Engine Performance ◽  
Engine Operation ◽  
Capacitive Discharge ◽  
Ignition System ◽  
Single Cylinder ◽  
Spark Plug ◽  
Discharge Ignition ◽  
Directed Energy

Abstract The natural gas industry has seen a considerable increase in production recently as the world seeks out new sources of economical, reliable, and more environmentally friendly energy. Moving this natural gas requires a complex network of pipelines and compressors, including reciprocating engines, to keep the gas moving. Many of these engines were designed more than 40 years ago and must be retrofit with modern technologies to improve their performance while simultaneously reducing the harmful emissions that they produce. In this study a directed energy ignition system is tested on a two-stroke, single cylinder, natural gas-fired engine. Stability and emissions will be observed throughout a range of spark waveforms for a single speed and load that enables the most fuel-lean operation of the engine. Improving the combustion process of the legacy pipeline engines is a substantial area of opportunity for reducing emissions output. One means of doing so is by improving an engines ability to operate at leaner conditions. To accomplish this, an ignition system needs to be able to send more energy to the spark plug in a controlled manner than a tradition capacitive-discharge ignition system. Controlling the energy is accomplished by optimizing the structure of the waveform or “profile” for each engine design. With this particular directed energy ignition system, spark profiles are able to be configured by changing the duration and amount of current sent to the spark plug. This study investigates a single operating speed and load for 9 different spark energy configurations. Engine operation at these test conditions will allow for emissions and engine performance data, using directed energy, to be analyzed in contrast to capacitive-discharge ignition.

Estimation of cycle-resolved in-cylinder pressure and air-fuel ratio using spark plug ionization current sensing

2001 ◽  
Vol 2 (4) ◽  
pp. 263-276 ◽  
Author(s):  
B Lee ◽  
Y G Guezennec ◽  
G Rizzoni
Keyword(s):  
Real Time ◽  
Combustion Process ◽  
Pressure Sensors ◽  
Cylinder Pressure ◽  
Current Signal ◽  
Ionization Current ◽  
Fuel Ratio ◽  
Spark Plug ◽  
Wide Range ◽  
Combustion Diagnostics

In recent years, several new sensor technologies have been developed and implemented within automotive industries due to the increasing requirements for improved engine performance and emission reduction. It requires detailed and specified knowledge of the combustion process inside the engine cylinder along with a sophisticated technique in engine diagnostics and control. During the last few years, the ionization current signal detection has been the emerging technology in the new sensor developments, in which the spark plug is used as a combustion probe, to improve the performance and emissions of an automobile engine. In this paper, a novel methodology will be presented which allows the cycle-resolved as well as the mean-value estimation of the air-fuel ratio and in-cylinder pressure based on the ionization current signal measurements. The implementation details of this methodology as well as extensive results will be presented for a wide range of air-fuel ratios. The main advantage of this new approach to process the ionization signal is its strong potential for real-time estimation of the air-fuel ratio and combustion diagnostics of individual cylinders and engine cycles. All the complex physics during the actual events (combustion process, ion generation, engine dynamics, etc.) are automatically self-extracted by this technique from acquired data in an initial off-line mapping phase. Once this has been performed, the air-fuel ratio and in-cylinder pressure can easily be estimated for each individual cylinder and combustion event in real-time with few computational requirements. Hence, this methodology has a high potential for the real-time combustion diagnostics and engine control based on the air-fuel ratio and in-cylinder pressure, while eliminating the requirements for installing expensive air-fuel ratio and in-cylinder pressure sensors. The results indicate that estimation of the cycle-resolved air-fuel ratio and in-cylinder pressure is reasonably accurate and robust, despite the inherently noisy character of the ionization signals, with estimation errors typically in the order of 2 per cent or less, except for very fuel-rich conditions.

Humid Air NOx Reduction Effect on Liquid Fuel Combustion

2002 ◽  
Author(s):  
Alexander G. Chen ◽  
Daniel J. Maloney ◽  
William H. Day
Keyword(s):  
Liquid Fuel ◽  
Nox Reduction ◽  
Flame Temperature ◽  
Substantial Reduction ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Humid Air ◽  
Wide Range ◽  
Reduction Of Nox ◽  
Reduction Effect

An experimental investigation was carried out at DOE NETL on the humid air combustion process using liquid fuel to determine the effects of humidity on pollutant emissions and flame stability. Tests were conducted at pressures of up to 100 psia (690 kPa), and a typical inlet air temperature of 860 °F (733 K). The emissions and RMS pressures were documented for a relatively wide range of flame temperature from 2440–3090 °F (1610 − 1970 K) with and without added humidity. The results show more than 90 percent reduction of NOx through 10 percent humidity addition to the compressed air compared with the dry case at the same flame temperature. The substantial reduction of NOx is due to a shift in the chemical mechanisms and cannot be explained by flame temperature reduction due to added moisture since the comparison was made for the same flame temperature.

Analysis of the Combustion Process in a EURO III Heavy-Duty Direct Injection Diesel Engine

2002 ◽  
Vol 124 (3) ◽  
pp. 636-644 ◽  
Author(s):  
J. M. Desantes ◽  
J. V. Pastor ◽  
J. Arre`gle ◽  
S. A. Molina
Keyword(s):  
High Speed ◽  
Direct Injection ◽  
Combustion Process ◽  
Engine Performance ◽  
Injection Pressure ◽  
Pollutant Emissions ◽  
Injection Timing ◽  
Engine Operation ◽  
Operation Conditions ◽  
Representative Points

To fulfill the commitments of future pollutant regulations, current development of direct injection (DI) Diesel engines requires to improve knowledge on the injection/combustion process and the effect of the injection parameters and engine operation conditions upon the spray and flame characteristics and how they affect engine performance and pollutant emissions. In order to improve comprehension of the phenomena inherent to Diesel combustion, a deep experimental study has been performed in a single-cylinder engine with the main characteristics of a six-cylinder engine passing the EURO III legislation. Some representative points of the 13-mode engine test cycle have been considered modifying the nominal values of injection pressure, injection load, intake pressure, engine speed, and injection timing. The study combines performance and emissions experimental measurements together with heat release law (HRL) analysis and high-speed visualization. Controlling parameters for BSFC, NOx, and soot emissions are identified in the last part of the paper.

Real-Time Processing of Engine Acoustic Emission for Diesel Injectors Diagnostic and Recentering

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Fabrizio Ponti ◽  
Vittorio Ravaglioli ◽  
Matteo De Cesare
Keyword(s):  
Diesel Engine ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Control Strategies ◽  
Combustion Process ◽  
Experimental Tests ◽  
Pollutant Emissions ◽  
Injection System ◽  
Real Time Processing ◽  
Injection Parameters

Diesel engine control strategies use complex injection patterns which are designed to meet the increasing request for engine-out emissions and fuel consumption reduction. As a result of the large number of tuneable injection parameters in modern injection systems (such as start and duration of each injection), injection patterns can be designed with many degrees-of-freedom. Each variation of the injection parameters modifies the whole combustion process and, consequently, engine-out emissions. Aging of the injection system usually affects injection location within the cycle as well as the amount of injected fuel (compared to the target value), especially for small pre-injections. Since diesel combustion is very sensitive to injection pattern variations, aging of injectors strongly affects engine behavior, in terms of both efficiency and pollutant emissions production. Moreover, such variations greatly affect other quantities related to the effectiveness of the combustion process, such as noise radiated by the engine. This work analyses the effects of pre-injection variations on combustion, pollutant emissions, and noise radiated by the engine. In particular, several experimental tests were run on a 1.3 L common rail diesel engine varying the amount of fuel injected in pre-injections. Torque delivered by the engine and center of combustion (MFB50) were kept constant using a specifically designed closed-loop combustion controller. During the tests, noise radiated by the engine was measured by properly processing the signal coming from a microphone faced to the engine block. The investigation of the correlation between the combustion process and engine noise can be used to setup a closed-loop algorithm for detecting and recentering injectors' drifts over time.

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