Hybrid combustion mode including flame propagation induced by spark ignition (SI) and auto-ignition could be an effective method to improve fuel economy and suppress engine knock simultaneously. An experimental research on controlled spark-assisted stratified compression ignition (SSCI) for this purpose was conducted in a gasoline direct injection (GDI) engine with high compression ratio. At wide open throttle (WOT) and minimum spark advance for best torque (MBT) condition without turbocharging, direct injection was used to form desired stoichiometric stratified mixture while 20% cooled external exhaust gas recirculation (e-EGR) was sucked into the cylinder. The combustion characteristics of controlled SSCI show two-stage heat release, where the first stage is caused by SI and the second stage is due to moderate auto-ignition. Compared with engine knock, the second stage heat release of controlled SSCI shows smooth pressure curve without pressure oscillation. This is due to the low energy density mixture around the cylinder wall caused by cooled e-EGR. The stratified mixture could suppress knock. Fuel economy and combustion characteristics of the baseline and the controlled SSCI combustion were compared. The baseline GDI engine reaches a maximum of 8.9 bar brake mean effective pressure (BMEP) with brake specific fuel consumption (BSFC) of 291 g/(kWh), and the controlled SSCI combustion achieves a maximum of 8.3 bar BMEP with BSFC of 256 g/(kWh), improving the fuel economy over 12% while maintaining approximately the same power. The results show that controlled SSCI with two-stage heat releases is a potential combustion strategy to suppress engine knock while achieving high efficiency of the high compression ratio gasoline engine.

References

References
1.
Zigler
,
B. T.
,
Walton
,
S. M.
,
He
,
X.
,
Wiswall
,
J. T.
,
Wooldridge
,
M. S.
, and
Wooldridge
,
S. T.
,
2006
, “
Crank-Angle Resolved Imaging of Homogeneous Charge Compression Ignition Phenomena in a Single-Cylinder Research Engine
,” Technical Meeting of the Central States Section of the Combustion Institute, Cleveland, OH, May 21–23, Paper #52.
2.
Zigler
,
B. T.
,
Stephen
,
M. W.
,
Karwat
,
D. M.
,
Assanis
,
D.
,
Wooldridge
,
M. S.
, and
Wooldridge
,
S. T.
,
2007
, “
A Multi-Axis Imaging Study of Spark-Assisted Homogeneous Charge Compression Ignition Phenomena in a Single-Cylinder Research Engine
,”
ASME
Paper No. ICEF2007-176210.1115/ICEF2007-1762.
3.
Wang
,
Z.
,
He
,
X.
,
Wang
,
J.-X.
,
Shuai
,
S.
,
Xu
,
F.
, and
Yang
,
D.
,
2010
, “
Combustion Visualization and Experimental Study on Spark Induced Compression Ignition (SICI) in Gasoline HCCI Engines
,”
Energy Convers. Manage.
,
51
(
5
), pp.
908
917
.10.1016/j.enconman.2009.11.029
4.
Wang
,
Z.
,
Wang
,
J.
,
Shuai
,
S.
,
He
,
X.
,
Xu
,
F.
,
Yang
,
D.
, and
Ma
,
X.
,
2009
, “
Research on Spark Induced Compression Ignition (SICI)
,”
SAE
Technical Paper No. 2009-01-013210.4271/2009-01-0132.
5.
Daw
,
C.
,
Stuart
,
K.
,
Edwards
,
D.
,
Wagner
,
R. M.
, and
Green
,
J. B.
,
2008
, “
Modeling Cyclic Variability in Spark-Assisted HCCI
,”
ASME J. Eng. Gas Turbines Power
,
130
(
5
), p.
052801
.10.1115/1.2906176
6.
Huang
,
Y.
,
Sung
,
C. J.
, and
Eng
,
J. A.
,
2004
, “
Dilution Limits of n-Butane/Air Mixtures Under Conditions Relevant to HCCI Combustion
,”
Combust. Flame
,
136
(
4
), pp.
457
466
.10.1016/j.combustflame.2003.10.011
7.
Hyvönen
,
J.
,
Haraldsson
,
G.
, and
Johansson
,
B.
,
2005
, “
Operating Conditions Using Spark Assisted HCCI Combustion During Combustion Mode Transfer to SI in a Multi-Cylinder VCR-HCCI Engine
,”
SAE
Technical Paper No. 2005-01-010910.4271/2005-01-0109.
8.
Glewen
,
W. J.
,
Wagner
,
R. M.
,
Edwards
,
K. D.
, and
Daw
,
C. S.
,
2002
, “
Analysis of Cyclic Variability in Spark-Assisted HCCI Combustion Using a Double Wiebe Function
,”
Proc. Combust. Inst.
,
32
(
2
), pp.
2885
2892
.10.1016/j.proci.2008.06.029
9.
Persson
,
H.
,
Johansson
,
B.
, and
Remón
,
A.
,
2007
, “
The Effect of Swirl on Spark Assisted Compression Ignition (SACI)
,”
SAE
Technical Paper No. 2007-01-185610.4271/2007-01-1856.
10.
Wagner
,
R. M.
,
Edwards
,
K. D.
,
Daw
,
C. S.
,
Green
,
J. B.
, and
Bunting
,
B. G.
,
2006
, “
On the Nature of Cyclic Dispersion in Spark Assisted HCCI Combustion
,”
SAE
Technical Paper No. 2006-01-041810.4271/2006-01-0418.
11.
Johansson
,
B.
,
2010
, “
Path to High Efficiency Gasoline Engine
,”
Directions in Engine-Efficiency and Emissions Reduction Conference
, Detroit, MI, Sept. 27–30.
12.
Natarajan
,
V. K.
,
Sick
,
V.
,
Reuss
,
D. L.
, and
Silvas
,
G.
,
2009
, “
Effect of Spark-Ignition on Combustion Periods During Spark-Assisted Compression Ignition
,”
Combust. Sci. Technol.
,
181
(
9
), pp.
1187
1206
.10.1080/00102200903074253
13.
Lavoie
,
G. A.
,
Martz
,
J.
,
Wooldridge
,
M.
, and
Assanis
,
D.
,
2010
, “
A Multi-Mode Combustion Diagram for Spark Assisted Compression Ignition
,”
Combust. Flame
,
157
(
6
), pp.
1106
1110
.10.1016/j.combustflame.2010.02.009
14.
Akihama
,
K.
,
Taki
,
M.
,
Takasu
,
S.
,
Ueda
,
T.
,
Iwashita
,
Y.
,
Farrell
,
J. T.
, and
Weissman
,
W.
,
2004
, “
Fuel Octane and Composition Effects on Efficiency and Emissions in a High Compression Ratio SIDI Engine
,”
SAE
Technical Paper No. 2004-01-195010.4271/2004-01-1950.
15.
Yun
,
H.
,
Wermuth
,
N.
, and
Najt
,
P.
,
2010
, “
Extending the High Load Operating Limit of a Naturally-Aspirated Gasoline HCCI Combustion Engine
,”
SAE
Technical Paper No. 2010-01-084710.4271/2010-01-0847.
16.
Saxena
,
S.
, and
Bedoya
,
I. D.
,
2013
, “
Fundamental Phenomena Affecting Low Temperature Combustion and HCCI Engines, High Load Limits and Strategies for Extending These Limits
,”
Prog. Energy Combust. Sci.
,
39
(
5
), pp.
457
488
.10.1016/j.pecs.2013.05.002
17.
Reuss
,
D. L.
,
Kuo
,
T. W.
,
Silvas
,
G.
,
Natarajan
,
V.
, and
Sick
,
V.
,
2008
, “
Experimental Metrics for Identifying Origins of Combustion Variability During Spark-Assisted Compression Ignition
,”
Int. J. Engine Res.
,
9
(
5
), pp.
409
434
.10.1243/14680874JER01108
18.
Xie
,
H.
,
Li
,
L.
,
Chen
,
T.
,
Yu
,
W.
,
Wang
,
X.
, and
Zhao
,
H.
,
2013
, “
Study on Spark Assisted Compression Ignition (SACI) Combustion With Positive Valve Overlap at Medium–High Load
,”
Appl. Energy
,
101
(
2013
), pp.
622
633
.10.1016/j.apenergy.2012.07.015
19.
Pastor
,
J. V.
,
García-Oliver
,
J. M.
,
García
,
A.
,
Micó
,
C.
, and
Durrett
,
R.
,
2013
, “
A Spectroscopy Study of Gasoline Partially Premixed Compression Ignition Spark Assisted Combustion
,”
Appl. Energy
,
104
, pp.
568
575
.10.1016/j.apenergy.2012.11.030
20.
Yoo
,
C. S.
,
Luo
,
Z.
,
Lu
,
T.
,
Kim
,
H.
, and
Chen
,
J. H.
,
2013
, “
A DNS Study of Ignition Characteristics of a Lean Iso-Octane/Air Mixture Under HCCI and SACI Conditions
,”
Proc. Combust. Inst.
,
34
(
2
), pp.
2985
2993
.10.1016/j.proci.2012.05.019
21.
Bhagatwala
,
A.
,
Chen
,
J. H.
, and
Lu
,
T.
,
2014
, “
Direct Numerical Simulations of HCCI/SACI With Ethanol
,”
Combust. Flame
,
161
(
7
), pp.
1826
1841
.10.1016/j.combustflame.2013.12.027
22.
Hoepke
,
B.
,
Jannsen
,
S.
,
Kasseris
,
E.
, and
Cheng
,
W. K.
,
2012
, “
EGR Effects on Boosted SI Engine Operation and Knock Integral Correlation
,”
SAE
Technical Paper No. 2012-01-070710.4271/2012-01-0707.
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