Enhancement of Combustion by Injection of Radicals

Murase, Eiichi; Hanada, K.

doi:10.4271/2000-01-0194

Cited by 34 publications

(15 citation statements)

References 12 publications

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“…The PFJ igniter is of the same size and shape as an ordinary spark plug, and it contains a small cavity and an orifice (Murase, 1995;Murase and Hanada, 2001, 2002, 2003Murase et al, 1996Murase et al, , 2004Oppenheim et al, 1990). The fuel injector is connected to the cavity via an insulator and a hollow center electrode.…”

Section: Pulsed Flame Jet (Pfj)mentioning

confidence: 99%

Photographic Observation and Emission Spectral Analysis of Homogeneous Charge Compression Ignition Combustion

Murase

Hanada

Miyaura

et al. 2005

Combustion Science and Technology

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Experimental studies of homogeneous charge compression ignition (HCCI) combustion have been conducted by using a compact rapid compression machine. The image of the cool flame was captured by a high-speed camera with image intensifier, and during the cool flame appearance the Emeleus cool flame band was observed. Then blue flame became evident, its emission spectrum being similar to that of the cool flame with overlapping by HCO bands. During the main heat release duration, the hot flame emission spectrum was observed, where the distinct OH emission appeared, and it was superimposed on the carbon monoxide oxidation continuum. After the main heat release, the broad peak of the spectrum was shifted to the longer-wavelength side, and the images of the flames changed to red, especially at higher equivalence ratios. This red coloration must originate from the H 2 O vibration-rotation bands (580.7-966.9 nm). On the other hand, it has been revealed that a pulsed flame jet (PFJ) has the potential for directly controlling the start of HCCI combustion. In the jet of PFJ, the emission spectrum obtained was composed of distinct OH and CH emissions superimposed on the carbon monoxide oxidation continuum.

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Section: Pulsed Flame Jet (Pfj)mentioning

confidence: 99%

Photographic Observation and Emission Spectral Analysis of Homogeneous Charge Compression Ignition Combustion

Murase

Hanada

Miyaura

et al. 2005

Combustion Science and Technology

Self Cite

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“…However, the significantly different boundary conditions on these apparatus could not reproduce the operating conditions of the engine. For example, the research carried out recently on CVC only had limited pressure of 1 to 5 bar [10][11][12], much lower than the PCC engine conditions. The difference in the operating pressure may cause disparities in the ignition mechanism.…”

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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“…The prechamber size and orifice diameter were examined in several studies [48][49][50]. It was determined that if the orifice diameter was too small, (d<1mm), the jet was not capable of igniting lean mixtures in the main chamber.…”

Section: Resultsmentioning

confidence: 99%

“…As a result, the exit velocity estimation was not experimentally viable. Murase and Hanada [48] showed that a faster pressure rise is attainable with the smaller orifice diameter (~ 2.5 mm compared to 4 mm), which greatly enhances the combustion process. In order to produce a substantial pressure rise in the prechamber, a smaller orifice is used and thus the use of a large orifice (d>3 mm) is avoided here.…”

Section: Resultsmentioning

confidence: 99%

Rapid compression machine study of a premixed, variable inlet density and flow rate, confined turbulent jet

Gholamisheeri

Thelen

Gentz

et al. 2016

Combustion and Flame

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The behavior of transient, compressible and combusting pre-mixed methane-air jets was experimentally studied with high speed imaging in a rapid compression machine. The jets were generated with a turbulent jet ignition system, which is a prechamber initiated combustion system. The absence of physical analyses of the characteristics of premixed turbulent jets was the motivation for the present study. Experiments were completed for turbulent jet ignition system orifice diameters of 2.0, 2.5 and 3.0 mm each at lean-to-stoichiometric equivalence ratios of φ=0.67, 0.8 and 1.0. The hot jet velocity at the orifice exit was calculated using mathematical correlations. The Mach number and Reynolds number were also computed. The high speed imaging shows the influence of orifice diameter on the flame propagation and the shape and structure of vortices resulting from the turbulent jet. Results revealed a direct relationship between orifice exit area reduction and a decrease in hot jet penetration speed. There was a reduction in hot jet penetration speed with an increase in the equivalence ratio. For the orifice diameters and equivalence ratios tested here, results showed that the jet evolved downstream of the orifice exit in partial agreement with existing correlations. Moreover, the jet was turbulent with calculated Reynolds numbers of around 20,000 or greater.

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Enhancement of Combustion by Injection of Radicals

Cited by 34 publications

References 12 publications

Photographic Observation and Emission Spectral Analysis of Homogeneous Charge Compression Ignition Combustion

Photographic Observation and Emission Spectral Analysis of Homogeneous Charge Compression Ignition Combustion

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

Rapid compression machine study of a premixed, variable inlet density and flow rate, confined turbulent jet

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