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 petroleum-based 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./vol. 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.

References

References
1.
Senda
,
J.
,
Okui
,
N.
,
Suzuki
,
T.
, and
Fujimoto
,
H.
, 2004, “
Flame Structure and Combustion Characteristics in Diesel Combustion Fueled With Bio-Diesel
,” SAE Paper No. 2004-01-0084.
2.
Lee
,
C. S.
,
Park
,
S. W.
, and
Kwon
,
S. I.
, 2005, “
An Experimental Study on the Atomization and Combustion Characteristics of Biodiesel-Blended Fuels
,”
Energy Fuels
,
19
(
5
), pp.
2201
2208
.
3.
Cheng
,
A. S.
,
Upatnieks
,
A.
, and
Mueller
,
C. J.
, 2006, “
Investigation of the Impact of Biodiesel Fueling on NOx Emissions Using an Optical Direct Injection Diesel Engine
,”
Int. J. Engine Res.
,
7
(
4
), pp.
297
318
.
4.
Leung
,
D. Y. C.
,
Luo
,
Y.
, and
Chan
,
T. L.
, 2006, “
Optimization of Exhaust Emissions of a Diesel Engine Fuelled With Biodiesel
,”
Energy Fuels
,
20
(
3
), pp.
1015
1023
.
5.
Mueller
,
C. J.
,
Boehman
,
A. L.
, and
Martin
,
G. C.
, 2009, “
An Experimental Investigation of the Origin of Increased NOx Emissions When Fueling a Heavy-Duty Compression-Ignition Engine With Soy Biodiesel
,” SAE Paper No. 2009-01-1792.
6.
Choi
,
C. Y.
,
Bower
,
G. R.
, and
Reitz
,
R. D.
, 1997, “
Mechanisms of Emissions Reduction Using Biodiesel Fuels
,” National Biodiesel Board, Final Report.
7.
Fang
,
T.
,
Lin
,
Y.-C.
,
Foong
,
T. M.
, and
Lee
,
C.-F. F.
, 2008, “
Spray and Combustion Visualization in an Optical HSDI Diesel Engine Operated in Low-Temperature Combustion Mode With Bio-Diesel and Diesel Fuels
,” SAE Paper No. 2008-01-1390.
8.
Zheng
,
M.
,
Mulenga
,
M. C.
,
Reader
,
G. T.
,
Wang
,
M.
, and
Ting
,
D. S.-K.
, 2006, “
Influence of Biodiesel Fuel on Diesel Engine Performance and Emissions in Low Temperature Combustion
,” SAE Paper No. 2006-01-3281.
9.
Heywood
,
J. B.
, 1988,
Internal Combustion Engine Fundamentals
,
McGraw-Hill
,
New York
.
10.
Jansons
,
M.
,
Brar
,
A.
,
Esterfanous
,
F.
,
Florea
,
R.
,
Taraza
,
D.
, and
Henein
,
N.
, 2008, “
Experimental Investigation of Single and Two-Stage Ignition in a Diesel Engine
,” SAE Paper No. 2008-01-1071.
11.
Genzale
,
C. L.
,
Reitz
,
R. D.
, and
Musculus
,
M. P. B.
, 2009, “
Optical Diagnostics and Multi-Dimensional Modeling of Spray Targeting Effects in Late-Injection Low-Temperature Diesel Combustion
,” SAE Paper No. 2009-01-2699.
12.
Hottel
,
H. C.
, and
Broughton
,
F. P.
, 1932, “
Determination of True Temperature and Total Radiation From Luminous Gas Flames
,”
Ind. Eng. Chem.
,
4
(
2
), pp.
166
175
.
13.
Svensson
,
K. I.
,
Mackrory
,
A. J.
,
Richards
,
M. J.
, and
Tree
,
D. R.
, 2005, “
Calibration of an RGB, CCD Camera and Interpretation of its Two-Color Images for KL and Temperature
,” SAE Paper No. 2005-01-0648.
14.
Ma
,
H.
,
Stevens
,
R.
, and
Stone
,
R.
, 2006, “
In-Cylinder Temperature Estimation From an Optical Spray-Guided DISI Engine With Color-Ratio Pyrometry (CRP)
,” SAE Paper No. 2006-01-1198.
15.
Zha
,
K.
,
Florea
,
R.-C.
, and
Jansons
,
M.
, 2011, “
Novel Implementation of Two-Color Soot Temperature Measurement in Optical Diesel Engine With High-Speed CMOS Digital Color Camera
,”
Proceedings of the International Conference on Advanced Research and Applications in Mechanical Engineering
.
16.
Stringer
,
V. L.
,
Cheng
,
W. L.
,
Lee
,
C.-F. F.
, and
Hansen
,
A. C.
, 2008, “
Combustion and Emissions of Biodiesel and Diesel Fuels in Direct Injection Compression Ignition Engines Using Multiple Injection Strategies
,” SAE Paper No. 2008-01-1388.
17.
Bai
,
C.
, and
Gosman
,
A. D.
, 1995, “
Development of Methodology for Spray Impingement Simulation
,” SAE Paper No. 950283.
18.
Lee
,
C. S.
, and
Reitz
,
R. D.
, 2001, “
Effect of Liquid Properties on the Breakup Mechanism of High-Speed Liquid Drops
,”
Atomization Sprays
,
11
(
1
), pp.
1
19
.
19.
McCrady
,
J. P.
,
Stringer
,
V. L.
,
Hansen
,
A. C.
, and
Lee
,
C.-F. F.
, 2007, “
Computational Analysis of Biodiesel Combustion in a Low-Temperature Combustion Engine Using Well-Defined Fuel Properties
,” SAE Paper No. 2007-01-0617.
20.
Yuan
,
W.
,
Hansen
,
A. C.
, and
Zhang
,
Q.
, 2003, “
Predicting the Physical Properties of Biodiesel for Combustion Modeling
,”
Trans. ASAE
,
46
(
6
), pp.
1487
1493
.
21.
Ronald
,
O.
,
Grover
,
J.
, and
Assanis
,
D. N.
, 2001, “
A Spray Wall Impingement Model Based Upon Conservation Principles
,”
Proceedings of the 5th International Symposium on Diagnostics and Modeling of Combustion in Internal Combustion Engines
22.
Cleary
,
D. J.
, and
Farrell
,
P. V.
, 1994, “
The Effects of Wall Temperature on Flame Structure During Flame Quenching
,” SAE Paper No. 940683.
23.
Zhao
,
H.
, and
Ladommatos
,
N.
, 2001,
Engine Combustion Instrumentation and Diagnostics
,
Society of Automotive Engineers Inc.
,
Warrendale, PA
.
24.
Matsui
,
Y.
,
Kamimoto
,
T.
, and
Matsuoka
,
S.
, 1980, “
A Study on the Application of the Two-Color Method to the Measurement of Flame Temperature and Soot Concentration in Diesel Engines
,” SAE Paper No. 800970.
You do not currently have access to this content.