Implementation of two color method to investigate late cycle soot oxidation process in a CI engine under low load conditions

López, J. Javier; Martín, Javier Rodríguez; García, Antonio; Villalta, David; Warey, Alok

doi:10.1016/j.applthermaleng.2016.11.095

Cited by 22 publications

(15 citation statements)

References 26 publications

(47 reference statements)

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“…On the other hand, the Apparent Combustion Time (ACT) parameter was used to estimate mixing capability. It is the dwell time between the instant where a certain percentage of the mass of fuel has been injected and the instant where this same percentage is burned [31]. In this study, it was used ACT -1 , which is considered as a mixing capability tracer.…”

Section: Engine Efficiency Studymentioning

confidence: 99%

A Combination of Swirl Ratio and Injection Strategy to Increase Engine Efficiency

Olmeda

Martín

García

et al. 2017

SAE Int. J. Engines

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SAE InternationalOlmeda, P.; Martín, J.; García Martínez, A.; Villalta-Lara, D.; Doménech Llopis, V. (2017). A Combination of Swirl Ratio and Injection Strategy to Increase Engine Efficiency. AbstractGrowing awareness about CO2 emissions and their environmental implications are leading to an increase in the importance of thermal efficiency as criteria to design internal combustion engines (ICE). Heat transfer to the combustion chamber walls contributes to a decrease in the indicated efficiency. A strategy explored in this study to mitigate this efficiency loss is to promote low swirl conditions in the combustion chamber by using low swirl ratios. A decrease in swirl ratio leads to a reduction in heat transfer, but unfortunately, it can also lead to worsening of combustion development and a decrease in the gross indicated efficiency. Moreover, pumping work plays also an important role due to the effect of reduced intake restriction to generate the swirl motion. Current research evaluates the effect of a dedicated injection strategy to enhance combustion process when low swirl is used. For this purpose, a combination of theoretical (0D and 1D models) and experimental tools were used. In particular, experiments were conducted in a single-cylinder directinjection light-duty diesel engine. The analysis also included theoretical calculations to estimate pumping losses. Results show that an increase in swirl ratio leads to an increase in the gross indicated efficiency (balancing heat transfer losses and combustion improvement) but the higher pumping losses negate this positive benefit. In the lowest swirl ratio case, a suitable injection strategy based on multiple injections, together with an increase in the injection pressure, can provide similar gross indicated efficiency as high swirl ratio case while avoiding high pumping losses.

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Section: Engine Efficiency Studymentioning

confidence: 99%

A Combination of Swirl Ratio and Injection Strategy to Increase Engine Efficiency

Olmeda

Martín

García

et al. 2017

SAE Int. J. Engines

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“…It is important to highlight that only a small amount of soot formed makes it into the exhaust. Figure shows the correlation between the maximum amount of soot formed (peak value of soot concentration, KL) and concentration of PM emissions in the exhaust for different measured engine conditions [14]. Thus, two groups of results are clearly observed: on the one hand, the square symbols points out a group of results in which the PM emissions are similar and low independently on the peak value of soot concentration, KL and therefore independently on the value of soot formed in-cylinder.…”

Section: Introductionmentioning

confidence: 99%

“…Considering diesel fuel and operating conditions tested, the oxidation process is mainly responsible for the exhaust PM emissions in a CI diesel engine under real conditions. [14].…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the main objective of this work was to compare different engine strategies to enhance the late cycle mixing controlled combustion process and therefore to improve the soot oxidation process while maintaining similar gross indicated efficiency in a lightduty engine. For this purpose, a simplified methodology defined in [14] was used, which analyzed the effect of mixing process and in-cylinder bulk gas temperature on soot oxidation during the late cycle combustion. Experimental measurements were made in a single-cylinder direct-injection light-duty diesel engine varying the swirl ratio and the injection pattern as injection pressure, Start of Energizing (SoE), Energizing Time (ET) and number of injections events.…”

Section: Introductionmentioning

confidence: 99%

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Swirl ratio and post injection strategies to improve late cycle diffusion combustion in a light-duty diesel engine

Benajes

Martín

García

et al. 2017

Applied Thermal Engineering

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Nitrogen oxides (NOx) and soot emissions are the most important pollutants from directinjection diesel engines. In particular, soot formation and oxidation determine the net engine-out soot emissions. These phenomena are complex and competing processes during diesel combustion. Despite many researches implicate the mechanisms of soot formation with soot emissions, the enhancement of the late cycle soot oxidation is the dominant mechanism for a reduction of engine-out soot emissions. The mixing process and the in-cylinder bulk temperature are two important parameters in the development of soot oxidation process. The current research compares different engine strategies to enhance the late cycle mixing controlled combustion process and therefore enhance soot oxidation while maintaining similar gross indicated efficiency in a light-duty engine. For this purpose, a simplified methodology has been used, which analyzes the effect of mixing process and in-cylinder bulk gas temperature on soot oxidation during the late cycle combustion. For carrying out this research, theoretical and experimental tools were used. In particular, the experimental measurements were made in a single-cylinder directinjection light-duty diesel engine varying the swirl ratio and the injection pattern as injection pressure, Start of Energizing (SoE), Energizing Time (ET) and number of injections events. To analyze soot emissions, the combustion luminosity was measured by an optoelectronic probe and the optical thickness parameter (KL) was evaluated by the two-color pyrometry method. The apparent combustion time (ACT-1) was used as mixing time tracer. Results show that an increase in swirl ratio implies an improvement on the mixing process and higher values of average bulk temperature during the late-cycle diffusion combustion. Both phenomena produce an enhancement in the soot oxidation process. In the lowest swirl ratio case, a suitable injection strategy based on multiple injections, provides similar results of soot oxidation process (and therefore, the emissions) as high swirl ratio case.

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“…For soot formation process, the local equivalence ratio is a significant factor given that the soot precursors are generated in the fuel-rich premixed burn region [43,44]. For the soot oxidation process, López et al [45] pointed out that the mixing capability and bulk temperature are the main impact factors, and a parameter is defined to explain the mixing capability. As seen in Figure 7, for the same fuel, an obviously lower percentage of large-value KL are demonstrated under 21% ambient O 2 concentration at the end stage of combustion, while there is not clear difference between two ambient O 2 concentrations at the beginning stage of combustion.…”

Section: Flame Temperaturementioning

confidence: 99%

Spray Combustion Characteristics and Soot Emission Reduction of Hydrous Ethanol Diesel Emulsion Fuel Using Color-Ratio Pyrometry

Zhang

et al. 2017

Energies

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To elucidate the relationship between physicochemical properties, spray characteristics, and combustion performance, a series of experiments have been conducted in a constant volume vessel with injection of hydrous ethanol diesel emulsion and regular diesel. HE30 (emulsion with 30% volume fraction of 20% water-containing ethanol and 70% volume fraction of 0# diesel) is developed using Shah's technique and regular diesel is also employed for comparison. Firstly, the physicochemical properties of two kinds of fuels are investigated. Then, the non-evaporating and evaporating spray characteristics are examined through the high-speed shadowgraphs. Finally, spray combustion experiments under different ambient oxygen concentrations are carried out, and color-ratio pyrometry (CRP) is applied to measure the flame temperature and soot concentration (KL) distributions. The results indicate that the physicochemical properties, such as density, surface tension, kinematic viscosity, cetane number, and oxygen content, have significant impact on the spray mixture formation and combustion performance. HE30 exhibits lower soot emissions than that of regular diesel. Further analysis supports the standpoint that the hydrous ethanol diesel emulsion can suppress the soot and NO x simultaneously. Therefore, the hydrous ethanol diesel emulsion has great potential to be an alternative clean energy resource.

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Implementation of two color method to investigate late cycle soot oxidation process in a CI engine under low load conditions

Cited by 22 publications

References 26 publications

A Combination of Swirl Ratio and Injection Strategy to Increase Engine Efficiency

A Combination of Swirl Ratio and Injection Strategy to Increase Engine Efficiency

Swirl ratio and post injection strategies to improve late cycle diffusion combustion in a light-duty diesel engine

Spray Combustion Characteristics and Soot Emission Reduction of Hydrous Ethanol Diesel Emulsion Fuel Using Color-Ratio Pyrometry

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