Temporal measurements of mass concentration of soot aggregates in diesel exhaust by a two-wavelength extinction method

Abstract

An optical instrument was developed that is based on a two-wavelength extinction principle and is used to measure the temporal mass concentration of soot aggregates in diesel exhaust. Two laser beams in coaxial alignment transmit a gas sample flow and the transmittances at two wavelengths are measured simultaneously. The specific extinction is determined by a comparison of mass concentrations measured at steady operation conditions by both the extinction and paper filter methods. The soot mass concentration is calculated from the measured transmittance value using the specific extinction obtained. It is demonstrated by experiments with two EURO III direct injection diesel engines that the developed instrument is able to measure the soot mass concentration under transient modes. A theoretical approach to quantify the ratio of scattering to absorption of diesel soot aggregates is proposed whereby the transmittance values measured at two wavelengths and electron micrographs are incorporated into the soot aggregate scattering theory. The refractive index of the diesel soot aggregates is finally determined so that the measured specific absorption could fit a calculated one.

Keywords

diesel engine particulate emissions laser diagnostics extinction method

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References

Mohr

Lehman

Margaria

ACEA program on the emissions of fine particulates from passenger cars (2), Part 2: Effect of sampling conditions and fuel sulfur content on the particle emission

SAE Paper 2003-01-1890, 2003.

Kittelson

D. B.

Engines and nanoparticles: A review

J. Aerosol Sci. 1998, 29, 575–588.

Khalek

I. A.

Littelson

Brear

The influence of dilution conditions on diesel exhaust particle size distribution measurements

SAE Paper 1999-01-1142, 1999.

Okrent

D. A.

Optimization of third generation TEOM monitor for measuring diesel particulate in real-time

SAE Paper 980409, 1998.

Gilbert

M. S.

Clark

N. N.

Measurement of particulate matter from diesel engine exhaust using a tapered element oscillating microbalance

Int. J. Engine Res. 2001, 2(4), 277–287.

Kawai

Iuti

Nakamura

Ishida

Real time analysis of particulate matter by flame ionization detection

SAE Paper 980048, 1998.

Heimgartner

Schraml

Will

Leipertz

Laser-induced incandescence soot analyzer (LI²SA) for soot mass concentration and primary particle size measurement in engine exhaust gases In Proceedings of the Conference on Diagnostics and Modeling of Combustion in Internal Combustion Engines (COMODIA 2001), Nagoya, Japan, 2001, pp. 604–612.

Bachalo

D. B.

Sankar

S. V.

Smallwood

G. J.

Snelling

D. R. S.

Development of the laser-induced incandescence method for the reliable characterization of particulate emissions

In the 11th International Symposium on Applications of Laser Techniques to Fluid Mechanics, Lisbon, Portugal, 2002, pp. 1–20.

Melton

L. A.

Soot diagnostics based on laser heating

Appl. Optics 1984, 23(13), 2201–2208.

10.

Dec

J. E.

Soot distribution in a D.I. diesel engine using 2-D imaging of laser-induced incandescence, elastic scattering, and flame luminosity

SAE Paper 920115, 1992.

11.

Kosaka

Nishigaki

Kamimto

Harada

A study on soot formation and oxidation in an unsteady spray flame via laser induced incandescence and scattering techniques

SAE Paper 952451, 1995.

12.

13.

Laile

Zahoransky

R. A.

Mohr

Claussen

Optical on-line time resolved particle measurements in the exhaust gas of diesel engines for different test cycles In the 6th International Conference on Engines for Automobile (ICE2003), SAE Technical Paper Series, SAE-NA 2003-01-56, 2003.

14.

Merola

S. S.

Vaglieco

B. M.

Zarinchang

Simultaneous detection of NO_x and particulate in exhaust of a CR diesel engine by UV-visible spectroscopy

SAE Paper 2003-01-0786, 2003.

15.

Khalek

I. A.

Kittelson

D. B.

Brear

Nanoparticle growth during dilution and cooling of diesel exhaust: Experimental investigation and theoretical assessment

SAE Paper 2000-01-0515, 2000.

16.

Dobbins

R. A.

Mulholland

G. W.

Bryner

N. P.

Comparison of a fractal smoke optics model with light extinction measurements

Atmos. Environ. 1994, 28(5), 889–897.

17.

Lapuerta

Aras

Hernandez

J. J.

Ballesteros

Estimation of diesel particulate emissions from hydrocarbon emissions and smoke opacity. In Thermo- and Fluid Dynamic Processes in Diesel Engines (THESEL 2002), Valencia, Spain, 2002, pp. 8–10.

18.

Kihara

Tsukamoto

Real-time on-board measurement of mass emissions of NO_x, THC and particulate matter from diesel vehicle. In Proceedings of the Conference on Diagnostics and Modeling of Combustion in Internal Combustion Engines (COMODIA 2001), Nagoya, Japan, 2001, pp. 71–76.

19.

Scherrer

H. C.

Kittelson

D. B.

Dolan

D. F.

Light absorption measurements of diesel particulate matter

SAE Paper 810181, 1981.

20.

Roessler

D. M.

Diesel particle mass concentration by optical techniques

Appl. Optics 1982, 21(22), 4077–4086.

21.

Dalzell

W. H

Sarofim

A. F.

Optical constants of soot and their application to heat-flux calculations

J. Heat Transfer 1969, 91, 100–104.

22.

Park

Appleton

J. P.

Shock-tube measurements of soot oxidation rates

Combust. Flame 1973, 20, 369–379.

23.

Koylu

U. O.

Faeth

G. M.

Structure of over-fire soot in buoyant turbulent diffusion flames at long residence times

Combust. Flame 1992, 89, 140–156.

24.

Fugiwara

Fukazawa

Growth and combustion of soot particulates in the exhaust of diesel engines

SAE Paper 800984, 1984.

25.

Smith

G. W.

Kinetic aspects of diesel soot coagulation

SAE Paper 820466, 1982.

26.

Puri

Richardson

T. F.

Santoro

R. J.

Dobbins

R. A.

Aerosol dynamic processes of soot aggregates in a laminar ethene diffusion flame

Combust. Flame 1993, 92, 320–333.

27.

Mountain

R. D.

Mulholland

G. W.

Light scattering from simulated smoke agglomerates

Langmuir 1988, 4, 1321–1326.

28.

Mohr

Lehman

Margaria

ACEA program on the emissions of fine particulates from passenger cars (2), Part 1: Particle characterization of wide range of engine technologies

SAE Paper 2003-01-1889, 2003.