The Effects of Turbulent Jet Characteristics on Engine Performance Using a Pre-Chamber Combustor

Bunce, Michael; Blaxill, Hugh; Kulatilaka, Waruna D.; Jiang, Naibo

doi:10.4271/2014-01-1195

Cited by 92 publications

(45 citation statements)

References 20 publications

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“…Toulson [18] and Attard [19] compared the combustion process of PCC and SI under the same optical engine and found that the PCC ignition presents much faster and more stable combustion at λ=1.8 compared to the SI mode at λ=1.4. Bunce et al [20] applied high-speed OH* and CH* chemiluminescence imaging to evaluate the turbulent jet characteristics of a PCC engine. By comparing simultaneously acquired flame jet image and PC/MC pressure, they found that the first visible flame jets appeared around the peak of the PC pressure for different PC nozzle orifices diameter designs.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Negative PLIF and OH* Chemiluminescence Imaging of the Gas Exchange and Flame Jet from a Narrow Throat Pre-Chamber

Tang¹,

Sampath²,

Marquez³

et al. 2020

SAE Technical Paper Series

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Pre-chamber combustion (PCC) is a promising engine combustion concept capable of extending the lean limit at part load. The engine experiments in the literature showed that the PCC could achieve higher engine thermal efficiency and much lower NOx emission than the spark-ignition engine. Improved understanding of the detailed flow and combustion physics of PCC is important for optimizing the PCC combustion. In this study, we investigated the gas exchange and flame jet from a narrow throat pre-chamber (PC) by only fueling the PC with methane in an optical engine. Simultaneous negative acetone planar laser-induced fluorescence (PLIF) imaging and OH* chemiluminescence imaging were applied to visualize the PC jet and flame jet from the PC, respectively. Results indicate a delay of the PC gas exchange relative to the built-up of the pressure difference (△P) between PC and the main chamber (MC). This should be due to the gas inertia inside the PC and the resistance of the PC nozzle. The PC jet can be either continuous or intermittent depending on the △P and pressure fluctuation amplitude. Distinct PC jet with low speed is witnessed after 15° CA ATDC, which could account for the postcombustion of the PCC engine in the literature. The probability distribution analysis of the PLIF and OH* images presents a much longer penetration length of the PC jet than that of the flame jet. This means that the flame jet resides in an atmosphere of the unburned gas mixture from the PC when it appears in the MC. The flame jet and PC jet show longer penetration length and become more stable with the enriching of the prechamber charge from lean to stoichiometric. However, the overall PC jet characteristics regarding the penetration length and probability distribution become less sensitive to the PC global excess air ratio (λ) when the PC charge is close to stoichiometry.

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Section: Introductionmentioning

confidence: 99%

Simultaneous Negative PLIF and OH* Chemiluminescence Imaging of the Gas Exchange and Flame Jet from a Narrow Throat Pre-Chamber

Tang¹,

Sampath²,

Marquez³

et al. 2020

SAE Technical Paper Series

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show abstract

“…Prechamber combustion can be referred to as a "prechamber combustor" [7], "prechamber ignition" [3], "torch ignition" [8][9][10], "jet ignition" [11][12][13][14][15][16], "two-stage combustion" [17][18][19], and "scavenged prechamber" [2,20]. Results from these studies validate the advantages of the fuel-added prechamber for SI engines and confirm the lean-burning and fuel-saving efficiencies of prechambers with an additional fuel delivery nozzle.…”

Section: Introductionmentioning

confidence: 65%

A Charge Possibility of an Unfueled Prechamber and Its Fluctuating Phenomenon for the Spark Ignited Engine

2020

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The demand for internal combustion engines remains high for mobile power sources in all fields due to their low costs, running distance capacity, charging reliability, and heavy driving durability. However, air pollution, efficiency, and environmental factors make this more challenging. According to recent research, using a fueled prechamber can lead to lean combustion in the main chamber, resulting in increased efficiency, reduced fuel consumption, and reduced toxic emissions. However, difficulties in producing a fueled prechamber for commercial engines include mixture and soot formation problems in the limited space of the prechamber, and limited research on the charging possibility of the unfueled prechamber. A removable prechamber is advantageous for used vehicles because an engine redesign is not required. Therefore, we proposed to use an unfueled prechamber to enhance the lean burning efficiency of the spark ignited (SI) engine and explore the possibility of charging an unfueled, unscavenged prechamber with a fuel-rich mixture. Consequently, investigating the possibility of filling an unfueled prechamber with a fuel-rich mixture without additional fuel delivery or an air control system was the aim of this study. For this purpose, the charge flowrate of the centrally located unfueled prechamber is extensively investigated by using Computational Fluid Dynamics (CFD), through its design. As a result, a realizable charge flow was detected for the unfueled prechamber in two periods in the inlet and compression strokes. Most importantly, we found fluctuation phenomena in mass flow rates at the inlet stroke directing a charge flow of the richer mixture into an unfueled prechamber without additional systems. Moreover, keeping the charged rich mixture inside the prechamber during the compression stroke is as important as charging the prechamber with the fuel-rich mixture. The study will enable us to produce a removable prechamber to improve the combustion efficiency of port injected engines.

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“…The engine speed was chosen as follows. Considering the simulation and experimental results of jet-ignition systems in [18,19], the main-combustion chamber burn duration of our jet ignition system was estimated to be around 20 crank degrees with λ = 1.75. From the RCM experimental data shown in Fig.…”

Section: Simulation Results and Experimental Valida-tionmentioning

confidence: 99%

A Control-Oriented Jet Ignition Combustion Model for an SI Engine

Song

Gentz

Zhu

et al. 2015

Volume 1: Adaptive and Intelligent Systems Control; Advances in Control Design Methods; Advances in Non-Linear and Optimal Cont

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A turbulent jet ignition system of a spark ignited (SI) engine consists of pre-combustion and main-combustion chambers, where the combustion in the main-combustion chamber is initiated by turbulent jets of reacting products from the pre-combustion chamber. If the gas exchange and combustion processes are accurately controlled, the highly distributed ignition will enable very fast combustion and improve combustion stability under lean operations, which leads to high thermal efficiency, knock limit extension, and near zero NOx emissions. For model-based control, a precise combustion model is a necessity. This paper presents a control-oriented jet ignition combustion model, which is developed based on simplified fluid dynamics and thermodynamics, and implemented into a dSPACE based real-time hardware-in-the-loop (HIL) simulation environment. The two-zone combustion model is developed to simulate the combustion process in two combustion chambers. Correspondingly, the gas flowing through the orifices between two combustion chambers is divided into burned and unburned gases during the combustion process. The pressure traces measured from a rapid compression machine (RCM), equipped with a jet igniter, are used for initial model validation. The HIL simulation results show a good agreement with the experimental data.

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The Effects of Turbulent Jet Characteristics on Engine Performance Using a Pre-Chamber Combustor

Cited by 92 publications

References 20 publications

Simultaneous Negative PLIF and OH* Chemiluminescence Imaging of the Gas Exchange and Flame Jet from a Narrow Throat Pre-Chamber

Simultaneous Negative PLIF and OH* Chemiluminescence Imaging of the Gas Exchange and Flame Jet from a Narrow Throat Pre-Chamber

A Charge Possibility of an Unfueled Prechamber and Its Fluctuating Phenomenon for the Spark Ignited Engine

A Control-Oriented Jet Ignition Combustion Model for an SI Engine

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