A phenomenological model for the description of unburned hydrocarbons emission in ultra-lean engines

The adoption of lean-burn concepts for internal combustion engines working with a homogenous air/fuel charge is under development as a path to simultaneously improve thermal efficiency, fuel consumption, nitric oxides, and carbon monoxide emissions. This technology may lead to a relevant emission of unburned hydrocarbons (uHC) compared to a stoichiometric engine. The uHC sources are various and the relative importance varies according to fuel characteristics, engine operating point, and some geometrical details of the combustion chamber. This concern becomes even more relevant in the case of engines supplied with natural gas since the methane has a global warming potential much greater than the other major pollutant emissions. In this work, a simulation model describing the main mechanisms for uHC formation is proposed. The model describes uHC production from crevices and flame wall quenching, also considering the post-oxidation. The uHC model is implemented in commercial software (GT-Power) under the form of “user routine”. It is validated with reference to two large bore engines, whose bores are 31 and 46 cm (engines named accordingly W31 and W46). Both engines are fueled with natural gas and operated with lean mixtures (λ > 2), but with different ignition modalities (pre-chamber device or dual fuel mode). The engines under study are preliminarily schematized in the 1D simulation tool. The consistency of 1D engine schematizations is verified against the experimental data of BMEP, air flow rate, and turbocharger rotational speed over a load sweep. Then, the uHC model is validated against the engine-out measurements. The averaged uHC predictions highlight an average error of 7% and 10 % for W31 and W46 engines, respectively. The uHC model reliability is evidenced by the lack of need for a case-dependent adjustment of its tuning constants, also in presence of relevant variations of both engine load and ring pack design.

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1D Simulation and Experimental Analysis on the Effects of the Injection Parameters in Methane–Diesel Dual-Fuel Combustion

Energies ◽

10.3390/en13143734 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3734

Author(s):

Javier Monsalve-Serrano ◽

Giacomo Belgiorno ◽

Gabriele Di Blasio ◽

María Guzmán-Mendoza

Keyword(s):

Natural Gas ◽

Internal Combustion Engines ◽

Large Scale ◽

Internal Combustion ◽

Fuel Combustion ◽

Pollutant Emissions ◽

Dual Fuel ◽

Combustion Engines ◽

Low Carbon ◽

Dual Fuel Combustion

Notwithstanding the policies that move towards electrified powertrains, the transportation sector mainly employs internal combustion engines as the primary propulsion system. In this regard, for medium- to heavy-duty applications, as well as for on- and off-road applications, diesel engines are preferred because of the better efficiency, lower CO2, and greater robustness compared to spark-ignition engines. Due to its use at a large scale, the internal combustion engines as a source of energy depletion and pollutant emissions must further improved. In this sense, the adoption of alternative combustion concepts using cleaner fuels than diesel (e.g., natural gas, ethanol and methanol) presents a viable solution for improving the efficiency and emissions of the future powertrains. Particularly, the methane–diesel dual-fuel concept represents a possible solution for compression ignition engines because the use of the low-carbon methane fuel, a main constituent of natural gas, as primary fuel significantly reduces the CO2 emissions compared to conventional liquid fuels. Nonetheless, other issues concerning higher total hydrocarbon (THC) and CO emissions, mainly at low load conditions, are found. To minimize this issue, this research paper evaluates, through a new and alternative approach, the effects of different engine control parameters, such as rail pressure, pilot quantity, start of injection and premixed ratio in terms of efficiency and emissions, and compared to the conventional diesel combustion mode. Indeed, for a deeper understanding of the results, a 1-Dimensional spray model is used to model the air-fuel mixing phenomenon in response to the variations of the calibration parameters that condition the subsequent dual-fuel combustion evolution. Specific variation settings, in terms of premixed ratio, injection pressure, pilot quantity and combustion phasing are proposed for further efficiency improvements.

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Lean-burn CNG engine with ignition chamber: from the idea to a running engine

Combustion Engines ◽

10.19206/ce-2019-101 ◽

2019 ◽

Vol 176 (1) ◽

pp. 3-9 ◽

Cited By ~ 3

Author(s):

Michael WEIßNER ◽

Frank BEGER ◽

Martin SCHÜTTENHELM ◽

Gunesh TALLU

Keyword(s):

Natural Gas ◽

Internal Combustion Engines ◽

State Of The Art ◽

Combustion Engines ◽

Lean Burn ◽

Compressed Natural Gas ◽

Emission Regulations ◽

Cng Engine ◽

Funded Project ◽

The Eu

Current and further developing CO2- and emission regulations worldwide and the competition to full electric mobility deliver a chal-lenge for internal combustion engines in general. A state of the art solution is the use of natural gas mainly contending methane to reduce CO2 significantly and to offer lowest emission levels. The EU-funded project GasOn developed engine concepts to fully exploit the advantages of CNG. This article describes the development of an innovative, monovalent engine dedicated to Compressed Natural Gas (CNG) and characterised by the lean burn concept and the innovative pre-chamber combustion.

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A quasi-one-dimensional model for an outwardly opening poppet-type direct gas injector for internal combustion engines

International Journal of Engine Research ◽

10.1177/1468087419871117 ◽

2019 ◽

Vol 21 (8) ◽

pp. 1493-1519

Author(s):

Abhishek Y Deshmukh ◽

Carsten Giefer ◽

Dominik Goeb ◽

Maziar Khosravi ◽

David van Bebber ◽

...

Keyword(s):

Natural Gas ◽

Internal Combustion Engines ◽

Flow Model ◽

Direct Injection ◽

Source Model ◽

Gas Jet ◽

Nozzle Flow ◽

Combustion Engines ◽

Compressed Natural Gas ◽

One Dimensional

Direct injection of compressed natural gas in internal combustion engines is a promising technology to achieve high indicated thermal efficiency and, at the same time, reduce harmful exhaust gas emissions using relatively low-cost fuel. However, the design and analysis of direct injection–compressed natural gas systems are challenging due to small injector geometries and high-speed gas flows including shocks and discontinuities. The injector design typically involves either a multi-hole configuration with inwardly opening needle or an outwardly opening poppet-type valve with small geometries, which make accessing the near-nozzle-flow field difficult in experiments. Therefore, predictive simulations can be helpful in the design and development processes. Simulations of the gas injection process are, however, computationally very expensive, as gas passages of the order of micrometers combined with a high Mach number compressible gas flow result in very small simulation time steps of the order of nanoseconds, increasing the overall computational wall time. With substantial differences between in-nozzle and in-cylinder length and velocity scales, simultaneous simulation of both regions becomes computationally expensive. Therefore, in this work, a quasi-one-dimensional nozzle-flow model for an outwardly opening poppet-type injector is developed. The model is validated by comparison with high-fidelity large-eddy simulation results for different nozzle pressure ratios. The quasi-one-dimensional nozzle-flow model is dynamically coupled to a three-dimensional flow solver through source terms in the governing equations, named as dynamically coupled source model. The dynamically coupled source model is then applied to a temporal gas jet evolution case and a cold flow engine case. The results show that the dynamically coupled source model can reasonably predict the gas jet behavior in both cases. All simulations using the new model led to reductions of computational wall time by a factor of 5 or higher.

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Blended hydrogen–natural gas-fueled internal combustion engines and fueling infrastructure

Compendium of Hydrogen Energy ◽

10.1016/b978-1-78242-363-8.00008-6 ◽

2016 ◽

pp. 219-232 ◽

Cited By ~ 4

Author(s):

J.R. Anstrom ◽

K. Collier

Keyword(s):

Natural Gas ◽

Internal Combustion Engines ◽

Internal Combustion ◽

Combustion Engines ◽

Gas Fueled

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Effect of Fuel and Air Dilution on Syngas Combustion in an Optical SI Engine

Energies ◽

10.3390/en12081566 ◽

2019 ◽

Vol 12 (8) ◽

pp. 1566 ◽

Cited By ~ 2

Author(s):

S.D. Martinez-Boggio ◽

S.S. Merola ◽

P. Teixeira Lacava ◽

A. Irimescu ◽

P.L. Curto-Risso

Keyword(s):

Internal Combustion Engines ◽

Combustion Process ◽

Visible Spectrum ◽

Propagation Speed ◽

Fuel Mixture ◽

Operating Conditions ◽

Inert Gases ◽

Pollutant Emissions ◽

Si Engine ◽

Lean Burn

To mitigate the increasing concentration of carbon dioxide in the atmosphere, energy production processes must change from fossil to renewable resources. Bioenergy utilization from agricultural residues can be a step towards achieving this goal. Syngas (fuel obtained from biomass gasification) has been proved to have the potential of replacing fossil fuels in stationary internal combustion engines (ICEs). The processes associated with switching from traditional fuels to alternatives have always led to intense research efforts in order to have a broad understanding of the behavior of the engine in all operating conditions. In particular, attention needs to be focused on fuels containing relatively high concentrations of hydrogen, due to its faster propagation speed with respect to traditional fossil energy sources. Therefore, a combustion study was performed in a research optical SI engine, for a comparison between a well-established fuel such as methane (the main component of natural gas) and syngas. The main goal of this work is to study the effect of inert gases in the fuel mixture and that of air dilution during lean fuelling. Thus, two pure syngas blends (mixtures of CO and H2) and their respective diluted mixtures (CO and H2 with 50vol% of inert gases, CO2 and N2) were tested in several air-fuel ratios (stoichiometric to lean burn conditions). Initially, the combustion process was studied in detail by traditional thermodynamic analysis and then optical diagnostics were applied thanks to the optical access through the piston crown. Specifically, images were taken in the UV-visible spectrum of the entire cycle to follow the propagation of the flame front. The results show that hydrogen promotes flame propagation and reduces its distortion, as well as resulting in flames evolving closer to the spark plug. All syngas blends show a stable combustion process, even in conditions of high air and fuel dilution. In the leanest case, real syngas mixtures present a decrease in terms of performance due to significant reduction in volumetric efficiency. However, this condition strongly decreases pollutant emissions, with nitrogen oxide (NOx) concentrations almost negligible.

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Development of the Control and Acquisition System for a Natural-Gas Spark-Ignition Engine Test Bench

Volume 6: Energy ◽

10.1115/imece2019-11485 ◽

2019 ◽

Cited By ~ 2

Author(s):

Lorenzo Gasbarro ◽

Jinlong Liu ◽

Christopher Ulishney ◽

Cosmin E. Dumitrescu ◽

Luca Ambrogi ◽

...

Keyword(s):

Natural Gas ◽

Internal Combustion Engines ◽

Test Bench ◽

Spark Ignition ◽

Operating Conditions ◽

Spark Ignition Engine ◽

Acquisition System ◽

Combustion Engines ◽

Engine Test ◽

New Sensors

Abstract Investigations using laboratory test benches are the most common way to find the technological solutions that will increase the efficiency of internal combustion engines and curtail their emissions. In addition, the collected experimental data are used by the CFD community to develop engine models that reduce the time-to-market. This paper describes the steps made to increase the reliability of engine experiments performed in a heavy-duty natural-gas spark-ignition engine test-cell such as the design of the control and data acquisition system based on Modbus TCP communication protocol. Specifically, new sensors and a new dynamometer controller were installed. The operation of the improved test bench was investigated at several operating conditions, with data obtained at both high- and low-sampling rates. The results indicated a stable test bench operation.

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Lean-Burn Natural Gas Engines: Challenges and Concepts for an Efficient Exhaust Gas Aftertreatment System

Emission Control Science and Technology ◽

10.1007/s40825-020-00176-w ◽

2020 ◽

Author(s):

Patrick Lott ◽

Olaf Deutschmann

Keyword(s):

Natural Gas ◽

Carbon Dioxide Emissions ◽

Rational Design ◽

Catalytic Converter ◽

Pollutant Emissions ◽

Exhaust Gas ◽

Lean Burn ◽

Aftertreatment System ◽

Natural Gas Engines ◽

Exhaust Gas Aftertreatment

AbstractHigh engine efficiency, comparably low pollutant emissions, and advantageous carbon dioxide emissions make lean-burn natural gas engines an attractive alternative compared to conventional diesel or gasoline engines. However, incomplete combustion in natural gas engines results in emission of small amounts of methane, which has a strong global warming potential and consequently makes an efficient exhaust gas aftertreatment system imperative. Palladium-based catalysts are considered as most effective in low temperature methane conversion, but they suffer from inhibition by the combustion product water and from poisoning by sulfur species that are typically present in the gas stream. Rational design of the catalytic converter combined with recent advances in catalyst operation and process control, particularly short rich periods for catalyst regeneration, allow optimism that these hurdles can be overcome. The availability of a durable and highly efficient exhaust gas aftertreatment system can promote the widespread use of lean-burn natural gas engines, which could be a key step towards reducing mankind’s carbon footprint.

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A design tool for the performances comparison of innovative energy systems for naval applications

E3S Web of Conferences ◽

10.1051/e3sconf/201911302005 ◽

2019 ◽

Vol 113 ◽

pp. 02005

Author(s):

D. Rattazzi ◽

M. Rivarolo ◽

T. Lamberti ◽

L. Magistri

Keyword(s):

Gas Turbines ◽

Internal Combustion Engines ◽

Energy Systems ◽

Design Tool ◽

Pollutant Emissions ◽

Combustion Engines ◽

Wide Range ◽

Storage Technologies ◽

Market Solutions ◽

And Storage

This paper aims to develop a tool for the performances comparison of innovative energy systems on board ships, both for concentrated and distributed generation applications. In the first part of the study, the tool database has been developed throughout a wide analysis of the available market solutions in terms of energy generation devices (i.e. fuel cells, internal combustion engines, micro gas turbines), fuels (hydrogen, natural gas, diesel) and related storage technologies. Many of these data have been collected also thanks to the laboratory experience of the authors’ research group on different innovative energy systems. From the database, a wide range of maps has been created, correlating costs, volumes, weights and emissions with the installed power and the operational hours required, given by the user as input. The tool highlights the best solution according to the different relevance chosen by the user for each key parameter (i.e. costs, volumes, emissions). In the second part, two different case studies are presented in order to underline how the installed power, the different ship typology and the user requirements affect the choice of the best solution. It is worth noting that the methodology has a general value, as the tool can be applied to both the design of new ships, and to the retrofit of already existing ships in order to respect new requirements (e.g. more and more stringent normative in terms of pollutant emissions in ports and restricted areas). Furthermore, the database can be easily extended to other generation and storage technologies.

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Oxygen Sensor Testing for Automotive Applications

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.896.249 ◽

2020 ◽

Vol 896 ◽

pp. 249-254

Author(s):

Dragos Tutunea ◽

Ilie Dumitru ◽

Oana Victoria Oţăt ◽

Laurentiu Racila ◽

Ionuţ Daniel Geonea ◽

...

Keyword(s):

Internal Combustion Engines ◽

Oxygen Sensor ◽

Oxygen Sensors ◽

Pollutant Emissions ◽

Combustion Engines ◽

Automotive Applications ◽

Combustion Gases ◽

Experimental Stand ◽

Residual Oxygen ◽

Sensor Degradation

During the operation of internal combustion engines the air-fuel ratio (A/F) is an important parameter which affects fuel consumption and pollutant emissions. The automotive oxygen sensor (Lambda) measures the quantity of residual oxygen in the combustion gases. Sensor degradation in time due to the exposure to high temperatures causes a distortion in controlling the A/F with the increase in gas emissions. In this paper an experimental stand is designed to test oxygen sensor degradation in laboratory condition. Four oxygen sensors were tested function of temperature and time recording their variation in resistance and voltage. The results showed similar values in the curves for all sensors tested.

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