A Study on the Application of the Two–Color Method to the Measurement of Flame Temperature and Soot Concentration in Diesel Engines

Matsui, Yukio; Kamimoto, Takeyuki; Matsuoka, Satoshi

doi:10.4271/800970

Cited by 65 publications

(24 citation statements)

References 2 publications

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“…However, the impact of cylinder head reflection on the estimation of soot optical thickness KL is far greater, and up to a 50% difference is observed for a majority of valid pixels when this effect is considered. This KL uncertainties are considerably higher than that reported by Matsui et al [24] implying that the total reflectivity assumption is an over estimate.…”

Section: Resultscontrasting

confidence: 61%

Soot Evolution With Cyclic Crank-Angle-Resolved Two-Color Thermometry in an Optical Diesel Engine Fueled With Biodiesel Blend and ULSD

Zha

Florea

Jansons

2012

Journal of Engineering for Gas Turbines and Power

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Biodiesel is a desirable alternative fuel for the diesel engine due to its low engine-out soot emission tendency. When blended with petroleum-based diesel fuels, soot emissions generally decrease in proportion to the volume fraction of biodiesel in the mixture. While comparisons of engine-out soot measurements between biodiesel blends and petroleumbased diesel have been widely reported, in-cylinder soot evolution has not been experimentally explored to the same extent. To elucidate the soot emission reduction mechanism of biodiesel, a single-cylinder optically-accessible diesel engine was used to compare the in-cylinder soot evolution when fueled with ultra-low sulfur diesel (ULSD) to that using a B20 biodiesel blend (20% vol.lvol. biodiesel ASTM D6751-03A). Soot temperature and KL factors are simultaneously determined using a novel two-color optical thermometry technique implemented with a high-speed CMOS color camera having wide-band Bayer filters. The crank-angle resolved data allows quantitative comparison of the rate of in-cylinder soot formation. High-speed spray images show that B20 has more splashing during spray wall impingement than ULSD, distributing rebounding fuel droplets over a thicker annular ring interior to the piston bowl periphery. The subsequent soot luminescence is observed by high-speed combustion imaging and soot temperature and KL factor measurements. B20 forms soot both at low KL magnitudes over large areas between fuel jets, and at high values among remnants of the fuel spray, along its axis and away from the bowl edge. In contrast, ULSD soot luminescence is observed exclusively as pool burning on the piston bowl surfaces resulting from spray wall impingement. The soot KL factor evolution during B20 combustion indicates earlier and significantly greater soot formation than with ULSD. B20 combustion is also observed to have a greater soot oxidation rate, which results in lower late-cycle soot emissions. For both fuels, higher fuel injection pressure led to lower late-cycle soot KL levels. The apparent rate of heat release (ARHR) analysis under steady skip-fire conditions indicates that B20 combustion is less sensitive to wall temperature than that observed with ULSD due to a lesser degree of pool burning. B20 was found to have both a shorter ignition delay and shorter combustion duration than ULSD.

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Section: Resultscontrasting

confidence: 61%

Soot Evolution With Cyclic Crank-Angle-Resolved Two-Color Thermometry in an Optical Diesel Engine Fueled With Biodiesel Blend and ULSD

Zha

Florea

Jansons

2012

Journal of Engineering for Gas Turbines and Power

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“…where  is again in units of m [58,61,62]. Finally, the spectral intensity of radiation emitted from a blackbody at a temperature T s is given by Planck's equation [ where C 1 = 3.7419 x 10 -16 Wm 2 and C 2 = 14388 mK are the blackbody radiation constants, and n is the refractive index of the medium between the detector and the emitter (assumed = 1 herein).…”

Section: Appendix a -Relationship Between Sinl Signal And Radiative Hmentioning

confidence: 99%

An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

Mueller¹,

Boehman²,

Martin³

2009

SAE Int. J. Fuels Lubr.

319

233

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The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE's peer review process under the supervision of the session organizer. This process requires a minimum of three (3) reviews by industry experts. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. ISSN 0148-7191 Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. SAE ABSTRACTIt is generally accepted that emissions of nitrogen oxides (NO x ) increase as the volume fraction of biodiesel increases in blends with conventional diesel fuel. While many mechanisms based on biodiesel effects on incylinder processes have been proposed to explain this observation, a clear understanding of the relative importance of each has remained elusive.To gain further insight into the cause(s) of the biodiesel NO x increase, experiments were conducted in a singlecylinder version of a heavy-duty diesel engine with extensive optical access to the combustion chamber. The engine was operated using two biodiesel fuels and two hydrocarbon reference fuels, over a wide range of loads, and using undiluted air as well as air diluted with simulated exhaust gas recirculation. Measurements were made of cylinder pressure, spatially integrated natural luminosity (a measure of radiative heat transfer), engine-out emissions of NO x and smoke, flame lift-off length, actual start of injection, ignition delay, and efficiency. Adiabatic flame temperatures for the test fuels and a surrogate #2 diesel fuel also were computed at representative diesel-engine conditions.Results suggest that the biodiesel NO x increase is not quantitatively determined by a change in a single fuel property, but rather is the result of a number of coupled mechanisms whose effects may tend to reinforce or cancel one another under different conditions, depending on specific combustion and fuel characteristics. Nevertheless, charge-gas mixtures that are closer to stoichiometric at ignition and in the standing premixed autoignition zone near the flame liftoff length appear to be key factors in helping to explain the biodiesel NO x increase under all conditions. These differences are expected to lead to higher local and average in-cylinder temperatures, lower radiative heat losses, and a shorter, more-advanced combustion event, all of which would be expected to increase thermal NO x emissions. Differences in prompt NO formation and species concentrations resulting from fuel and jet-structure changes also may play important roles.

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“…where the KL factor is proportional to the total soot volume (discussed below) and α is an empirical constant (typically α = 1 . 39 ). For wavelengths in the visible range, α has a negligible effect on the calculated temperature and KL , 7,23 and soot samples deposited on a piston window indicated α = 1 . 38 . 24 An evaluation using Rayleigh–Debye–Gans (RDG) theory for light scattering by soot aggregates and an assumed constant refractive index resulted in α = 1 . 31 ; however, the temperature and KL factor from this approach only resulted in a difference of 1%–2%, relative to a traditional pyrometric evaluation.…”

Section: Two-color Pyrometrymentioning

confidence: 97%

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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A Study on the Application of the Two–Color Method to the Measurement of Flame Temperature and Soot Concentration in Diesel Engines

Cited by 65 publications

References 2 publications

Soot Evolution With Cyclic Crank-Angle-Resolved Two-Color Thermometry in an Optical Diesel Engine Fueled With Biodiesel Blend and ULSD

Soot Evolution With Cyclic Crank-Angle-Resolved Two-Color Thermometry in an Optical Diesel Engine Fueled With Biodiesel Blend and ULSD

An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

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

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A Study on the Application of the Two–Color Method to the Measurement of Flame Temperature and Soot Concentration in Diesel Engines

Cited by 65 publications

References 2 publications

Soot Evolution With Cyclic Crank-Angle-Resolved Two-Color Thermometry in an Optical Diesel Engine Fueled With Biodiesel Blend and ULSD

Soot Evolution With Cyclic Crank-Angle-Resolved Two-Color Thermometry in an Optical Diesel Engine Fueled With Biodiesel Blend and ULSD

An Experimental Investigation of the Origin of Increased NOxEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel

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

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Product

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An Experimental Investigation of the Origin of Increased NO_xEmissions When Fueling a Heavy-Duty Compression-Ignition Engine with Soy Biodiesel