Operation strategy optimization of lean combustion using turbulent jet ignition at different engine loads

Hua, Jianxiong; Song, Yuntong; Zhou, Lei; Liu, Fengnian; Wei, Haiqiao

doi:10.1016/j.apenergy.2021.117586

Cited by 39 publications

(12 citation statements)

References 34 publications

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“…Overall (not shown), a larger throat radius yielded superior results, while eight-nozzle PCs mostly prevailed. Note that, although the base case has 12 nozzles, only six of them are functional; a detailed explanation can be found in [19]. Nozzle offset was beneficial to generate a swirl flow into the pre-chamber, thus helping mixing during the compression stroke (Figure 5); as an outcome of the geometrical and flow field related to a particular geometry, the pre-chamber composition is expected to play a critical role, as shown in a previous study.…”

Section: Results Of the Doe Exercisementioning

confidence: 75%

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DoE-ML guided optimization of an active pre-chamber geometry using CFD

Silva

Mohan

Badra

et al. 2022

International Journal of Engine Research

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An optimized active pre-chamber geometry was obtained by combining computational fluid dynamics (CFD) and machine learning (ML). A heavy-duty engine operating with methane under lean conditions was considered. The combustion process was modeled with a multi-zone well-stirred reactor (MZ-WSR) with a skeletal methane oxidation mechanism. The simulations were run for a complete cycle. For the optimization study, the pre-chamber was parametrized; six independent and three dependent variables were considered, while the volume was kept constant. Three hundred pre-chamber designs were generated, and a one-shot design of experiments (DoE) optimization was first considered. A merit function was adopted to rank the designs, and an optimum design was found from the DoE results, which yielded considerable improvements in merit ranking, considering fuel consumption, engine-out emissions, noise, and safety; secondly, machine learning algorithms were trained by utilizing the DoE results aiming at finding a globally optimum geometry for the considered operating condition. Five sequential iterations were performed, and the ML algorithms were capable of proposing a new design with superior performance compared to the best DoE.

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Section: Results Of the Doe Exercisementioning

confidence: 75%

“…Broad literature reports attempts to understand and optimize the pre-chamber operating conditions [18] [ 10,19], fuels [20], geometrical aspects [9,21,22], and driving cycle [23]. Despite that, the understanding of pre-chamber combustion and the role of the jet (thermal, chemical, and turbulence generation) remains incomplete.…”

Section: Introductionmentioning

confidence: 99%

DoE-ML guided optimization of an active pre-chamber geometry using CFD

Silva

Mohan

Badra

et al. 2022

International Journal of Engine Research

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“…In addition, lower flame propagation should be a critical factor for lean burn performance, which lead to inconspicuous improvement on thermal efficiency under ultra-lean burn conditions . Pre-chamber turbulent jet ignition is a technique that simultaneously employs these two lean burn limit expansion strategies . This technology replaces the spark plug in a conventional spark ignition engine with a pre-chamber .…”

Section: Introductionmentioning

confidence: 99%

“… 12 Pre-chamber turbulent jet ignition is a technique that simultaneously employs these two lean burn limit expansion strategies. 13 This technology replaces the spark plug in a conventional spark ignition engine with a pre-chamber. 14 When the engine requires ignition, the injector in the pre-chamber enriches the lean mixture in the pre-chamber, followed by the ignition of the spark plug in the pre-chamber.…”

Section: Introductionmentioning

confidence: 99%

High Compression Ratio Active Pre-chamber Single-Cylinder Gasoline Engine with 50% Gross Indicated Thermal Efficiency

Zhan

Chen

et al. 2023

ACS Omega

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Active pre-chamber turbulent jet ignition with a high compression ratio has been demonstrated to be an effective method for significantly enhancing engine thermal efficiency. A dual modification of the combustion chamber and the pre-chamber was performed on an AVL 5400 single-cylinder Miller engine to achieve stable ultra-lean burn at a high compression ratio, and a breakthrough of 51.10% gross indicated thermal efficiency was achieved at the compression ratio of 16.4 and λ = 2.236. Spark ignition and pre-chamber turbulent jet ignition exhibit significant performance diversities under lean burn conditions. Pre-chamber turbulent jet ignition is able to significantly expand the lean burn limit of spark ignition to λ = 2.7 (CoV IMEP < 5%) at only the expense of an increased HC emission, while apparently reducing fuel consumption and nitrogen oxide emissions. With an increase in the compression ratio from 13.6 to16.4, spark ignition and pre-chamber turbulent jet ignition exhibit contradictory performance laws. The engine performance of a spark ignition engine decreases significantly as the compression ratio increases, whereas a pre-chamber jet ignition engine can still operate reliably at a high compression ratio with ultra-lean combustion. Within the scope of the test, the performance of the pre-chamber jet ignition engine is enhanced by a greater compression ratio. This improvement is primarily attributable to the reduction of heat transfer loss and exhaust energy loss under ultra-lean combustion, as determined by an analysis of the structure of power losses.

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“…Stable combustion with TJI and Miller cycle was achieved with lambda 1.6 in part load condition, resulting in a fuel economy about 9.6% to 12% in relation to a baseline operation (lambda 1). 24 In Brazil, hydrous ethanol is a promising alternative to gasoline. It is available in every gas station and the majority of the small vehicles fleet are equipped with flexible fuel engines, which are capable of using both ethanol, gasoline, and its mixtures.…”

Section: Introductionmentioning

confidence: 99%

Exploring the part load lean limit of a direct injection spark ignition engine fueled with ethanol

Golke

Prante

Garlet

et al. 2022

International Journal of Engine Research

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Stringent environmental legislation demands development of internal combustion engines seeking higher thermal efficiency to reduce greenhouse gas emissions. Brazilian governmental programs like ROTA 2030 and RenovaBio drive the research and development of highly efficient engines fueled with biofuels, like sugarcane bioethanol, that has a near to zero carbon footprint. Some technologies such as gasoline direct injection, variable valve train, and turbocharging were implemented in downsized Spark Ignition (SI) engines in order to reach higher thermal efficiencies and decrease CO2 emissions. Homogeneous lean combustion in SI operation can improve fuel consumption and reduce exhaust gas emissions. However, it is limited by combustion instability and the three-way-catalyst (TWC) inability to work properly converting nitrogen oxides (NOx). With lean combustion the NOx emissions could be significantly reduced, enabling the use of lean NOx trap (LNT) as an effective lower cost after treatment system. To explore the limits of homogeneous lean combustion in SI engines, experimental tests were performed to investigate performance, efficiency, combustion, and emission parameters of a multi-cylinder Ford 1.0l Ti-VCT EcoBoost engine fueled with hydrous ethanol. Hydrous ethanol is a commercial Brazilian fuel which has greater laminar flame speed and higher dilution tolerance than gasoline, and thus can increase combustion stability. Different fuel direct injection strategies were explored at part load (below 8.0 bar IMEP) at engine speed of 1500 rpm. Air-to-fuel ratio was varied from stoichiometric (lambda 1.0) to lambda 1.5. The limit of stable homogeneous lean combustion (COVIMEP ≤ 3.0%) was achieved in lambda 1.4. The lowest indicated load of 2.1 bar IMEP was limited by combustion stability at lambda 1.3. The maximum indicated efficiency was 36.9% at indicated load of 8.0 bar IMEP and lambda 1.4. The NOx emissions dropped below 1.4 g/kWh at 4.0 bar IMEP and lambda 1.4.

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Operation strategy optimization of lean combustion using turbulent jet ignition at different engine loads

Cited by 39 publications

References 34 publications

DoE-ML guided optimization of an active pre-chamber geometry using CFD

DoE-ML guided optimization of an active pre-chamber geometry using CFD

High Compression Ratio Active Pre-chamber Single-Cylinder Gasoline Engine with 50% Gross Indicated Thermal Efficiency

Exploring the part load lean limit of a direct injection spark ignition engine fueled with ethanol

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