Diesel flame imaging and quantitative analysis of in-cylinder soot oxidation

Kamimoto, Takeyuki; Uchida, Nozomu; Aizawa, Tetsuya; Kondo, Katsufumi; Kuboyama, Tatsuya

doi:10.1177/1468087416629282

Cited by 19 publications

(18 citation statements)

References 42 publications

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“…The optical piston allowed high-speed imaging visualization of the combustion chamber through the piston bowl. Resulting pictures were analyzed using the two-color method as described in previous studies [18]. This allowed the visualization of a temperature field inside the cylinder to identify the hot zones.…”

Section: Methodsmentioning

confidence: 99%

Thermal Efficiency Comparison of Different Injector Constellations in a CI Engine

Nyrenstedt

Watanabe²,

Enya³

et al. 2019

SAE Technical Paper Series

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More stringent emission regulations call for high-efficiency engines in the heavy-duty vehicle sector. Towards this goal, reduced heat losses, as well as increased work output, are needed. In this study, a multiple injector concept to control the combustion as well as reduce the hot boundary zones is proposed. Earlier studies have proven that multiple injectors experience lower heat losses and higher efficiency. However, a comprehensive investigation of the causes for experimental heat loss was not performed in depth. Experiments in a heavy-duty CI engine equipped with three injectors were thus performed. Engine configurations of single, dual and triple injectors were compared for a single-injection case as well as a multi-injection (Sabathe-cycle) case. Heat losses, efficiency and the emission levels were quantified and investigated. Optical experiments were performed to investigate the temperature field as well as flame behavior. This led to further understanding of the heat loss drivers. Experimental data was coupled with the double compression expansion engine concept for waste heat recovery, utilizing the energy from reduced heat losses. Notable findings included an efficiency increase of 1.9 %-points when using all three injectors for a single injection. Three injectors improved the efficiency an additional 1.2 %-points in a Sabathe-cycle case as compared to a single injector case. These gains mainly followed by reduced heat losses caused by hot zones being kept away from the boundaries. Thus, the benefits of multiple injectors were proven.

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Section: Methodsmentioning

confidence: 99%

Thermal Efficiency Comparison of Different Injector Constellations in a CI Engine

Nyrenstedt

Watanabe²,

Enya³

et al. 2019

SAE Technical Paper Series

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“…A temperature bias of up to 300 K has been predicted by Musculus et al [42], calculated based on 3D simulations. In this study, the degree of this bias has been evaluated by utilizing a simple two-layer soot model as previously used by Kamimoto et al [53]. Figure 15 (left) presents a schematic of the model: it assumes that the soot cloud consists of a cold fuel-rich inner-core and a thinner hot layer at the boundaries, where the soot is being oxidized.…”

Section: Correlation Of Soot Temperature and Oxidationmentioning

confidence: 99%

Optical Investigation of Sooting Propensity of n-Dodecane Pilot/Lean-Premixed Methane Dual-Fuel Combustion in a Rapid Compression-Expansion Machine

Srna¹,

Bruneaux²,

Rotz³

et al. 2018

SAE Int. J. Engines

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The sooting propensity of dual-fuel combustion with n-dodecane pilot injection in a lean-premixed methane-air charge has been investigated using an optically accessible Rapid Compression-Expansion Machine to achieve engine relevant pressure and temperature conditions at start of pilot injection. A Diesel injector with a 100 µm single-hole coaxial nozzle, mounted at the cylinder periphery, has been employed to admit the pilot fuel.The aim of this study was to enhance the fundamental understanding of soot formation and oxidation processes of n-dodecane in presence of methane in the air charge by parametric variation of methane equivalence ratio, charge temperature and pilot fuel injection duration. The influence of methane on ignition delay and flame extent of the pilot fuel jet has been determined by simultaneous OH* chemiluminescence and Schlieren imaging. The sooting behavior of the flame has been characterized using the 2D-DBI imaging methodology. The apparent soot black-body temperature has been measured 1D-resolved along the injector axis by applying an imaging spectrograph.Addition of methane into the air charge considerably prolongs the ignition delay with an increasing effect under less reactive conditions and with higher methane equivalence ratios. Therefore, the influence of methane on the formation of soot is two-fold: in case of short pilot injection, the presence of methane was found to decrease the soot formation due to the leaner pilot fuel mixture at time of ignition. For longer pilot fuel injections, methane enhances the soot production by decreasing oxygen availability and introducing additional carbon. In all cases, methane strongly defers the oxidation of soot due to the lower availability of oxygen.

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“…Payri et al 13 discussed the effect of the intensity non-uniformity along the LOS, as well as the effect of digitization uncertainty on a CCD sensor. LOS uncertainties are most significant for flames with optically thick regions ( KL > 1 ) , 20 and higher gradients, 8 particularly along the LOS. Correspondingly, the uncertainties are lower for homogeneous combustion strategies, lower temperature combustion strategies (due to generally lower gradients), 8 or later in the combustion process when the soot is more uniformly mixed.…”

Section: Two-color Pyrometrymentioning

confidence: 99%

“…Correspondingly, the uncertainties are lower for homogeneous combustion strategies, lower temperature combustion strategies (due to generally lower gradients), 8 or later in the combustion process when the soot is more uniformly mixed. 20 Table 1 summarizes the uncertainties relevant to two-color pyrometry as characterized in the literature. In general, the soot volume fraction and KL factor are more sensitive to uncertainties than the temperature.…”

Section: Two-color Pyrometrymentioning

confidence: 99%

“…For example, it has been used by Ma et al 10 to characterize soot in a direct injection spark-ignited (DISI) engine, and by Zha et al 11 to compare biodiesel blend and diesel combustion in a compression-ignition (CI) engine. In a more recent study, Kamimoto et al 20 used two-color pyrometry to study late-cycle soot oxidation in a heavy-duty diesel engine and a rapid compression and expansion machine. Using simulated soot mass histories, a surface-specific soot oxidation rate was evaluated.…”

Section: Introductionmentioning

confidence: 99%

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Refinement of the two-color pyrometry method for application in a direct injection diesel and natural gas compression-ignition engine

Khosravi

Kirchen

2019

Proceedings of the Institution of Mechanical Engineers, Part D:

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The soot emissions from internal combustion engines have significant health and environmental impacts and, as such, are subject to increasingly stringent regulations. Two-color pyrometry provides the in-cylinder soot cloud temperature and soot volume fraction and can provide insight to the in-cylinder soot formation and oxidation processes to guide research for reducing engine-out soot emissions. This work demonstrates improvements to the two-color pyrometry methodology, with a focus on low-temperature, low-soot regimes such as low-temperature combustion or combustion of direct injected natural gas. Through selection of a fast and robust numerical algorithm, characterizing and increasing the detection envelope, performing static and dynamic perspective adjustments, accounting for non-uniform and non-linear system response, as well as localized signal-to-noise ratio enhancement through image filtering, the performance of the pyrometric method was improved by a 40% increase in the resolved signal fraction. The refined two-color method was evaluated for both direct injected diesel and natural gas fueling strategies using a pilot-ignited direct injected natural gas fuel system and facilitated evaluation of local temperatures and soot concentrations in pilot-ignited direct injected natural gas combustion, despite the generally low soot levels in this combustion strategy.

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Diesel flame imaging and quantitative analysis of in-cylinder soot oxidation

Cited by 19 publications

References 42 publications

Thermal Efficiency Comparison of Different Injector Constellations in a CI Engine

Thermal Efficiency Comparison of Different Injector Constellations in a CI Engine

Optical Investigation of Sooting Propensity of n-Dodecane Pilot/Lean-Premixed Methane Dual-Fuel Combustion in a Rapid Compression-Expansion Machine

Refinement of the two-color pyrometry method for application in a direct injection diesel and natural gas compression-ignition engine

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