Study of Ignitability in Strong Flow Field

Suzuki, Kotaro; Uehara, Kazuhiro; Murase, Eiji; Nogawa, Shinichiro

doi:10.1007/978-3-319-45504-4_4

Cited by 15 publications

(6 citation statements)

References 5 publications

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“…Similar studies were conducted on the in-cylinder flow field and flame development in a spark ignition research engine, and concluded that increased bulk flame distortion may lead to slower burning due to the detrimental effects of flame stretch and thus, cancel out any benefits of a larger enflamed area due to higher flame distortion. 41,42 Brequigny et al 11 attempted to simulate the flow and combustion conditions in an engine cylinder with a fan in a spherical combustion vessel at 5000, 6000, and 7000 r/min fan speed. They observed a similar behavior as Figure 11 for the flame stretch with respect to the fan speed.…”

Section: Resultsmentioning

confidence: 99%

Experimental determination of flame speed and flame stretch using an optically accessible, spark-ignition engine

Afkhami

Wang

Miers

et al. 2019

International Journal of Engine Research

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The current research experimentally studied flame speed and stretch under engine in-cylinder conditions. A direct-injection, spark-ignition, and optically accessible engine was utilized to image the flame propagation, and E10 was selected as the fuel. Also, three fuel–air mixtures (stoichiometric, lean, and rich) were examined. The flame front was located by processing high-speed images. This study introduces a novel approach for calculation of equivalent spherical flame radius for analysis of flame speed and stretch. Flame front propagation analysis showed that during the flame propagation period, the stretch decreased until the flame front touched the piston surface. This was a common trend for stoichiometric, lean, and rich mixtures, which occurred because the flame radius was the dominant factor in the stretch calculation. In addition, the rich fuel–air mixture showed a lower flame stretch compared to stoichiometric or lean mixture. This was the result of a lower Markstein number for the rich fuel–air mixture. To study the sensitivity of different fuel–air mixtures to the flame stretch, the trajectory of the flame centroid was tracked until the flame front touched the piston surface. The results showed that the end centroid for the lean mixture deviated from the start point more than those of the rich and stoichiometric mixtures because the lean mixture had a higher flame stretch and lower flame speed. Furthermore, comparing the flame stretch at three different engine speeds revealed that increasing the engine speed increased the flame stretch, especially during the early flame development period. According to previous studies which discussed flame stretch as a flame extinguishment mechanism, the probability of flame extinction is higher when the engine speed is higher. Also, uncertainty analysis was conducted to determine the effect of camera setting on the flame stretch. Results showed that a maximum relative uncertainty of 4.5% occurred during the early flame development.

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Section: Resultsmentioning

confidence: 99%

Experimental determination of flame speed and flame stretch using an optically accessible, spark-ignition engine

Afkhami

Wang

Miers

et al. 2019

International Journal of Engine Research

View full text Add to dashboard Cite

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“…Suzuki suggested that the function of the discharge current level is to hold the discharge channel to form a large flame kernel while the discharge duration is to lead the flame fusion with repeating restrike events. 63 However, the benefit from either elevating the spark current level or extending the spark duration is saturated after a certain extent of enhancement. For a conventional TCI ignition system, the decaying triangular shape of the spark current is determined by the characteristics of the inductor discharge of the secondary coil.…”

Section: Discharge Current Controlled Ignitionmentioning

confidence: 99%

“…Suzuki et al investigated the misfire mechanism in strong flow fields, through optical measurement and numerical simulations. 63 The spark discharge channel blow-off is found responsible for the occurrence of the misfire, as a result of reduced burning velocity and decreased flame kernel volume in the detached area. Since the spark restrike phenomenon seems unavoidable in a strong flow field, the ability to withhold the spark channel longer time before the first restrike becomes critical.…”

Section: High-energy Spark Ignitionmentioning

confidence: 99%

Future gasoline engine ignition: A review on advanced concepts

Zheng

2020

International Journal of Engine Research

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To meet the future requirements of fuel economy and exhaust emissions, high-efficiency gasoline engines tend to employ diluted combustion concepts along with intensified charge motion and stratified mixtures. Securing the ignition of such mixtures over the full engine operation range is challenging, because of the lowered mixture reactivity and increased discrepancy of stoichiometry. In recent years, increasing research efforts have been spending on innovations of ignition technologies to tackle the challenges. In this paper, the directions of ignition improvement are highlighted based on the fundamental understanding of the ignition mechanisms. The working principles of the primary types of advanced ignition systems are introduced; and relevant engine and combustion vessel test results are reviewed. The ignition systems are categorized as: (1) high-energy spark ignition, (2) pulsed nanosecond discharge ignition, (3) radio-frequency plasma ignition, (4) laser-induced plasma ignition, and (5) pre-chamber ignition. The advanced ignition systems are commented, regarding the ignition effectiveness and the implementation challenges, according to the literatures and the extensive empirical work at the authors’ laboratory.

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“…If there is still certain amount of electrical energy left in the ignition coil after the plasma breaks off, a new plasma channel with shortened length is established near the spark gap, which is termed as restriking. 3,[11][12][13][14] Restrike happens more frequently when the discharge current is insufficient to hold the plasma under flow conditions. Frequent restriking is detrimental to flame kernel formation, because it reduces the effective plasma channel holding period and plasma length.…”

Section: Introductionmentioning

confidence: 99%

Investigation of multi-event spark discharge strategy for lean methane-air combustion

Zhu

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part D:

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The characterization of the single-coil repetitive discharge and the dual-coil offset discharge was conducted in a constant volume combustion chamber to better understand the operating principle of the multi-event spark ignition strategies. A parametric study of the dual-coil offset discharge was carried out through electric and optical diagnosis to identify the effective operational parameters, including coil working frequency, charging voltage, and coil inductances. Combustion tests under both quiescent and flow conditions with methane-air mixture were performed to demonstrate the ignition capability of the dual-coil offset strategy. Test results have shown that constantly depositing spark energy through offset discharge is beneficial to secure flame kernel. However, the offset discharge strategy requires a high working frequency, an elevated charging voltage, and fast reacting coils to maintain the spark plasma channel under high background pressure and intensified flow conditions.

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Study of Ignitability in Strong Flow Field

Cited by 15 publications

References 5 publications

Experimental determination of flame speed and flame stretch using an optically accessible, spark-ignition engine

Experimental determination of flame speed and flame stretch using an optically accessible, spark-ignition engine

Future gasoline engine ignition: A review on advanced concepts

Investigation of multi-event spark discharge strategy for lean methane-air combustion

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