A combined experimental and numerical study of thermal processes, performance and nitric oxide emissions in a hydrogen-fueled spark-ignition engine

Rakopoulos, C.D.; Kosmadakis, George; Demuynck, Joachim; Paepe, Michel De; Verhelst, Sebastian

doi:10.1016/j.ijhydene.2011.01.103

Cited by 45 publications

(33 citation statements)

References 42 publications

(84 reference statements)

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“…In the exhaust pipe a three-way-catalyst (TWC) is mounted, just after the EGR line, with a metallic substrate (type 'Bosal'), which has a light-off temperature of about 280- should be stressed that the exhaust gas temperature of the CFR engine is rather low [18], so it is necessary to place the TWC as close as possible to the engine exhaust valve, in order to operate with a high conversion efficiency. A sampling of the exhaust gases before and after the TWC was provided, and several temperature sensors were mounted in the inlet, exhaust, and EGR lines.…”

Section: Egr Experimental Testsmentioning

confidence: 99%

“…Next, the numerical model applied will be briefly described, since more detailed information can be found in previous studies [18,36].…”

Section: Numerical Modelmentioning

confidence: 99%

“…Its formulation is based on the compressible version of the standard law-of-the-wall [42], and it includes not only a pressure term, which has been also shown in [43,44] to give more accurate results, but also a combustion term. Its validation under firing conditions has been accomplished in [18].…”

Section: Cfd Modelmentioning

confidence: 99%

“…Apart from these experimental investigations, numerical tools are also developed [8,[13][14][15][16], which can further assist in the understanding of the various processes taking place in those engines. Especially, the results obtained from computational fluid dynamics (CFD) codes [8,16], which describe in a more fundamental way the in-cylinder processes [17,18], can identify at a local level the coupling of the relevant transport phenomena.…”

Section: Introductionmentioning

confidence: 99%

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CFD modeling and experimental study of combustion and nitric oxide emissions in hydrogen-fueled spark-ignition engine operating in a very wide range of EGR rates

Kosmadakis

Rakopoulos

Demuynck

et al. 2012

International Journal of Hydrogen Energy

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CFD modeling and experimental study of combustion and nitric oxide emissions in hydrogenfueled spark-ignition engine operating in a very wide range of EGR rates To refer to or to cite this work, please use the citation to the published version:Kosmadakis, G.D., Rakopoulos, C.D., Demuynck, J., De Paepe, M. & Verhelst, S. (2012). CFD modeling and experimental study of combustion and nitric oxide emissions in hydrogen-fueled spark-ignition engine operating in a very wide range of EGR rates. INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 37(14) ABSTRACTIn the current work, the variation of EGR rates is investigated in a hydrogen-fueled, sparkignition engine. This technique is followed in order to control the engine load and decrease the exhaust nitrogen oxides emissions. The external EGR is varied in the very wide range of 12% up to 47% (by mass), where in each test case the in-cylinder mixture is stoichiometric, diluted with the appropriate EGR rate. The operation of this engine is explored using measured data with the aid of a validated CFD code. Moreover, a new residual gas term existing in the expression of the hydrogen laminar flame speed, which has been derived from a one-dimensional chemical kinetics code, is tested in a real application for appraising its capabilities. The investigation conducted provides insight on the performance and indicated efficiency of the engine, the combustion processes, and the emissions of nitrogen oxides. More precisely, an experimental study has been deployed with the aim to identify the characteristics of such a technique, using very high EGR rates, focusing on the combustion phenomena. At the same time, the CFD results are compared with the corresponding measured ones, in order to evaluate the CFD code under such non-conventional operating conditions and to test a recent expression for the residual gas term included in the hydrogen laminar flame speed expression. It is revealed that the combustion takes place in few degrees of crank angle, especially at high engine loads (low EGR rates), whereas the exhaust nitrogen oxides emissions are significantly decreased in comparison to the use of lean mixtures for controlling the engine load. Additionally, the recent expression of the residual gas term, which has been tested and incorporated in the CFD code, seems to be adequate for the calculation of combustion phenomena in highly diluted, with EGR, hydrogen-fueled spark-ignition engines, as for every EGR rate tested (even for the higher ones) the computational results are compared in good terms with the measured data.

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Section: Egr Experimental Testsmentioning

confidence: 99%

“…Next, the numerical model applied will be briefly described, since more detailed information can be found in previous studies [18,36].…”

Section: Numerical Modelmentioning

confidence: 99%

Section: Cfd Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CFD modeling and experimental study of combustion and nitric oxide emissions in hydrogen-fueled spark-ignition engine operating in a very wide range of EGR rates

Kosmadakis

Rakopoulos

Demuynck

et al. 2012

International Journal of Hydrogen Energy

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“…It has a wide range of flammability [3,4] that allows engines to operate very lean and at high efficiency. This can also lead to greatly reduced NO X emissions at equivalence ratios lower than about 0.5 [5][6][7]. In order to eliminate hydrogen abnormal combustion modes such as pre-ignition and backfiring [8][9][10], injecting hydrogen directly into the combustion chamber (DI) after intake valves closure (IVC) has been proposed as a more suitable strategy in comparison to port fuel injection (PFI).…”

Section: Introductionmentioning

confidence: 99%

Computational Study of Hydrogen Direct Injection for Internal Combustion Engines

Hamzehloo¹,

Aleiferis²

2013

SAE Technical Paper Series

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Hydrogen has been largely proposed as a possible fuel for internal combustion engines. The main advantage of burning hydrogen is the absence of carbon-based tailpipe emissions. Hydrogen's wide flammability also offers the advantage of very lean combustion and higher engine efficiency than conventional carbon-based fuels. In order to avoid abnormal combustion modes like pre-ignition and backfiring, as well as air displacement from hydrogen's large injected volume per cycle, direct injection of hydrogen after intake valve closure is the preferred mixture preparation method for hydrogen engines. The current work focused on computational studies of hydrogen injection and mixture formation for direct-injection spark-ignition engines. Hydrogen conditions at the injector's nozzle exit are typically sonic. Initially the characteristics of under-expanded sonic hydrogen jets were investigated in a quiescent environment using both Reynolds-Averaged NavierStokes (RANS) and Large-Eddy Simulation (LES) techniques. Various injection conditions were studied, including a reference case from the literature. Different nozzle geometries were investigated, including a straight nozzle with fixed cross section and a stepped nozzle design. LES captured details of the expansion shocks better than RANS and demonstrated several aspects of hydrogen's injection and mixing. Incylinder simulations were also performed with a side 6-hole injector using 70 and 100 bar injection pressure. Injection timing was set to just after inlet valve closure with duration of 6 μs and 8 μs, leading to global air-to-fuel equivalence ratios  typically in the region of 0.2-0.4. The engine intake air pressure was set to 1.5 bar absolute to mimic boosted operation. It was observed that hydrogen jet wall impingement was always prominent. Comparison with non-fuelled engine conditions demonstrated the degree of momentum exchange between in-cylinder hydrogen injection and air motion. LES highlighted details of hydrogen's spatial distribution throughout the injection duration and up to ignition timing. Higher peak velocities were predicted by LES, especially on the tumble plane. With the employed injection strategy, the areas closer to the cylinder wall were richer in fuel than the centre of the chamber close to the end of compression.

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Internal Combustion Engine Performance and Emissions Aspects When Fueled by Conventional and Sustainable Fuels

Korakianitis

Imran

Emberson

et al. 2015

Handbook of Clean Energy Systems

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Internal combustion (IC) engines continue to maintain their position as principle prime mover for energy transformation especially in transportation and power sectors. Research on IC engines has many frontiers: optimum engine design to get better fuel utilization and mitigate spefici emissions; development of alternate fuels to reduce the dependence on fast depleting fossil fuels; use of oxygenated hydrocarbons in conventional compression ignition (CI) and spark ignition (SI) engines; development of reaction kinetics and thermal databases for different hydrocarbons to simulate combustion process in IC engines. This study reviews the status of the current research on all of the above mentioned frontiers. It lays down various parameters and their mutual dependencies and how they affect engine' performance and emissions characteristics. Various strategies that are employed to control these performance and emissions characteristics have been discussed. The application of different liquid (Alcohols and biofuels) and gaseous (natural gas and hydrogen) fuels as alternatives to the fossil fuels has been detailed. It also provides an insight into the development of various surrogates for gasoline and diesel fuels. Numerical modelling of the internal combustion engines and the application of emulsified nano‐fuels have also been discussed in detail.

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A combined experimental and numerical study of thermal processes, performance and nitric oxide emissions in a hydrogen-fueled spark-ignition engine

Cited by 45 publications

References 42 publications

CFD modeling and experimental study of combustion and nitric oxide emissions in hydrogen-fueled spark-ignition engine operating in a very wide range of EGR rates

CFD modeling and experimental study of combustion and nitric oxide emissions in hydrogen-fueled spark-ignition engine operating in a very wide range of EGR rates

Computational Study of Hydrogen Direct Injection for Internal Combustion Engines

Internal Combustion Engine Performance and Emissions Aspects When Fueled by Conventional and Sustainable Fuels

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