Abstract

Partial fuel stratification (PFS) is a promising fuel injection strategy to improve the stability of lean combustion by applying a small amount of pilot injection right before spark timing. Mixed-mode combustion, which makes use of end-gas autoignition following conventional deflagration-based combustion, can be further utilized to speed up the overall combustion. In this study, PFS-assisted mixed-mode combustion in a lean-burn direct injection spark-ignition (DISI) engine is numerically investigated using multi-cycle large eddy simulation (LES). A previously developed hybrid G-equation/well-stirred reactor combustion model for the well-mixed operation is extended to the PFS-assisted operation. The experimental spray morphology is employed to derive spray model parameters for the pilot injection. The LES-based model is validated against experimental data and is further compared with the Reynolds-averaged Navier–Stokes (RANS)-based model. Overall, both RANS and LES predict the mean pressure and heat release rate traces well, while LES outperforms RANS in capturing the cycle-to-cycle variation (CCV) and the combustion phasing in the mass burned space. Liquid and vapor penetrations obtained from the simulations agree reasonably well with the experiment. Detailed flame structures predicted from the simulations reveal the transition from a sooting diffusion flame to a lean premixed flame, which is consistent with experimental findings. LES captures more wrinkled and stretched flames than RANS. Finally, the LES model is employed to investigate the impacts of fuel properties, including heat of vaporization (HoV) and laminar burning speed (SL). Combustion phasing is found more sensitive to SL than to HoV, with a larger fuel property sensitivity of the heat release rate from autoignition than that from deflagration. Moreover, the combustion phasing in the PFS-assisted operation is shown to be less sensitive to SL compared with the well-mixed operation.

References

1.
World Energy Outlook 2019
”. IEA (2019), IEA, Paris, https://www.iea.org/reports/world-energy-outlook-2019
2.
Arcoumanis
,
C.
, and
Kamimoto
,
T.
,
2009
,
Flow and Combustion in Reciprocating Engines
,
Springer Science & Business Media
,
Berlin/Heidelberg
.
3.
Hu
,
Z.
,
Zhang
,
J.
,
Sjöberg
,
M.
, and
Zeng
,
W.
,
2019
, “
The Use of Partial Fuel Stratification to Enable Stable Ultra-Lean Deflagration-Based Spark-Ignition Engine Operation With Controlled End-Gas Autoignition of Gasoline and E85
,”
Int. J. Engine Res.
,
21
(
9
), pp.
1678
1695
,
4.
Nakai
,
E.
,
Goto
,
T.
,
Ezumi
,
K.
,
Tsumura
,
Y.
,
Endou
,
K.
,
Kanda
,
Y.
,
Urushihara
,
T.
,
Sueoka
,
M.
, and
Hitomi
,
M.
,
2019
, “
Mazda Skyactiv-X 2.0 L Gasoline Engine
,”
Proceedings of the 28th Aachen Colloquium Automobile and Engine Technology
,
Aachen, Germany
, SAE.
5.
Sjöberg
,
M.
,
Dec
,
J. E.
, and
Cernansky
,
N. P.
,
2005
, “
Potential of Thermal Stratification and Combustion Retard for Reducing Pressure-Rise Rates in HCCI Engines, Based on Multi-Zone Modeling and Experiments
,” and
SAE 2005 Transactions Journal of Engines-V114-3
, Paper No. 2005-01-0113.
6.
Yang
,
Y.
,
Dec
,
J. E.
,
Dronniou
,
N.
, and
Sjöberg
,
M.
,
2011
, “
Tailoring HCCI Heat-Release Rates with Partial Fuel Stratification: Comparison of Two-Stage and Single-Stage-Ignition Fuels
,”
Proc. Combust. Inst.
,
33
(
2
), pp.
3047
3055
.
7.
Szybist
,
J. P.
, and
Splitter
,
D. A.
,
2017
, “
Pressure and Temperature Effects on Fuels With Varying Octane Sensitivity At High Load in SI Engines
,”
Combust. Flame.
,
177
, pp.
49
66
.
8.
Kasseris
,
E.
, and
Heywood
,
J.
,
2012
, “
Charge Cooling Effects on Knock Limits in SI DI Engines Using Gasoline/ethanol Blends: Part 2-Effective Octane Numbers
,”
SAE. Int. J. Fuels. Lubr.
,
5
(
2
), pp.
844
854
.
9.
Kolodziej
,
C. P.
,
Pamminger
,
M.
,
Sevik
,
J.
,
Wallner
,
T.
,
Wagnon
,
S. W.
, and
Pitz
,
W. J.
,
2017
, “
Effects of Fuel Laminar Flame Speed Compared to Engine Tumble Ratio, Ignition Energy, and Injection Strategy on Lean and EGR Dilute Spark Ignition Combustion
,”
SAE. Int. J. Fuels. Lubr.
,
10
(
1
), pp.
82
94
.
10.
Yue
,
Z.
, and
Som
,
S.
,
2019
, “
Fuel Property Effects on Knock Propensity and Thermal Efficiency in a Direct-injection Spark-ignition Engine
,”
Appl. Energy
,
281
.
11.
Miles
,
P.
,
2018
, “
Efficiency Merit Function for Spark-ignition Engines: Revision and Improvements Based on FY16-17 Research
.” Technical Report. U.S. Department of Energy, Washington, DC, 2018. DOE/GO-102018-5041.
12.
Dahms
,
R.
,
Felsch
,
C.
,
Röhl
,
O.
, and
Peters
,
N.
,
2011
, “
Detailed Chemistry Flamelet Modeling of Mixed-Mode Combustion in Spark-assisted HCCI Engines
,”
Proc. Combust. Inst.
,
33
(
2
), pp.
3023
3030
.
13.
Middleton
,
R. J.
,
Olesky
,
L. K. M.
,
Lavoie
,
G. A.
,
Wooldridge
,
M. S.
,
Assanis
,
D. N.
, and
Martz
,
J. B.
,
2015
, “
The Effect of Spark Timing and Negative Valve Overlap on Spark Assisted Compression Ignition Combustion Heat Release Rate
,”
Proc. Combust. Inst.
,
35
(
3
), pp.
3117
3124
.
14.
Wang
,
X.
,
Xie
,
H.
,
Xie
,
L.
,
Zhang
,
L.
,
Li
,
L.
,
Chen
,
T.
, and
Zhao
,
H.
,
2013
, “
Numerical Simulation and Validation of SI-CAI Hybrid Combustion in a CAI/HCCI Gasoline Engine
,”
Combust. Theory Model.
,
17
(
1
), pp.
142
166
.
15.
Xu
,
C.
,
Pal
,
P.
,
Ren
,
X.
,
Sjöberg
,
M.
,
Van Dam
,
N.
,
Wu
,
Y.
,
Lu
,
T.
,
McNenly
,
M.
, and
Som
,
S.
,
2021
, “
Numerical Investigation of Fuel Property Effects on Mixed-Mode Combustion in a Spark-Ignition Engine
,”
ASME J. Energy. Res. Technol.
,
143
(
4
), p.
042306
.
16.
Joelsson
,
T.
,
Yu
,
R.
, and
Bai
,
X.-S.
,
2012
, “
Large Eddy Simulation of Turbulent Combustion in a Spark-Assisted Homogeneous Charge Compression Ignition Engine
,”
Combust. Sci. Technol.
,
184
(
7–8
), pp.
1051
1065
.
17.
Wang
,
X.
, and
Zhao
,
H.
,
2017
, “
Multi-Cycle Large Eddy Simulation (LES) of the Cycle-to-Cycle Variation (CCV) of Spark Ignition (SI)–Controlled Auto-Ignition (CAI) Hybrid Combustion in a Gasoline Engine
.” SAE Technical Paper 2017-01-2261.
18.
Richards
,
K. J.
,
Senecal
,
P. K.
, and
Pomraning
,
E.
,
2018
,
CONVERGE Manual (Version 2.4)
,
Convergent Science Inc.
,
Madison, WI
.
19.
Reitz
,
R. D.
,
1987
, “
Modeling Atomization Processes in High-Pressure Vaporizing Sprays
,”
Atomisat. Spray Technol.
,
3
(
4
), pp.
309
337
.
20.
Froessling
,
N.
,
1958
, “
Evaporation, Heat Transfer, and Velocity Distribution in Two-Dimensional and Rotationally Symmetrical Laminar Boundary-Layer Flow
.” Report No. NACA-TM-1432.
21.
Liu
,
A. B.
,
Mather
,
D.
, and
Reitz
,
R. D.
,
1993
, “
Modeling the Effects of Drop Drag and Breakup on Fuel Sprays
.” SAE Technical Paper 930072 and SAE 1993 Transactions Journal of Engines-V102-3.
22.
Amsden
,
A. A.
, and
Findley
,
M.
,
1997
, “
KIVA-3V: A Block-Structured KIVA Program for Engines With Vertical Or Canted Valves
,” Technical Report LA–13313-MS,
Los Alamos National Laboratory
,
Livermore, CA
.
23.
Pomraning
,
E.
, and
Rutland
,
C. J.
,
2002
, “
Dynamic One-Equation Nonviscosity Large-Eddy Simulation Model
,”
AIAA. J.
,
40
(
4
), pp.
689
701
.
24.
Pal
,
P.
,
Kolodziej
,
C. P.
,
Choi
,
S.
,
Som
,
S.
,
Broatch
,
A.
,
Gomez-Soriano
,
J.
,
Wu
,
Y.
,
Lu
,
T.
, and
See
,
Y. C.
,
2018
, “
Development of a Virtual CFR Engine Model for Knocking Combustion Analysis
,”
SAE Int. J. Engines
,
11
(
2018-01-0187
), pp.
1069
1082
.
25.
Peters
,
N.
,
2000
,
Turbulent Combustion
,
Cambridge University Press
,
Cambridge
.
26.
Pitsch
,
H.
, and
De Lageneste
,
L. D.
,
2002
, “
Large-Eddy Simulation of Premixed Turbulent Combustion Using a Level-Set Approach
,”
Proc. Combust. Inst.
,
29
(
2
), pp.
2001
2008
.
27.
Babajimopoulos
,
A.
,
Assanis
,
D.
,
Flowers
,
D.
,
Aceves
,
S.
, and
Hessel
,
R.
,
2005
, “
A Fully Coupled Computational Fluid Dynamics and Multi-Zone Model With Detailed Chemical Kinetics for the Simulation of Premixed Charge Compression Ignition Engines
,”
Int. J. Engine Res.
,
6
(
5
), pp.
497
512
.
28.
Zeng
,
W.
,
Sjöberg
,
M.
,
Reuss
,
D. L.
, and
Hu
,
Z.
,
2017
, “
High-Speed PIV, Spray, Combustion Luminosity, and Infrared Fuel-Vapor Imaging for Probing Tumble-Flow-Induced Asymmetry of Gasoline Distribution in a Spray-Guided Stratified-Charge DISI Engine
,”
Proc. Combust. Inst.
,
36
(
3
), pp.
3459
3466
.
29.
Leung
,
K. M.
,
Lindstedt
,
R. P.
, and
Jones
,
W. P.
,
1991
, “
A Simplified Reaction Mechanism for Soot Formation in Nonpremixed Flames
,”
Combust. Flame.
,
87
(
3–4
), pp.
289
305
.
30.
Zhou
,
B.
,
Brackmann
,
C.
,
Li
,
Z.
,
Aldén
,
M.
, and
Bai
,
X. S.
,
2015
, “
Simultaneous Multi-Species and Temperature Visualization of Premixed Flames in the Distributed Reaction Zone Regime
,”
Proc. Combust. Inst.
,
35
(
2
), pp.
1409
1416
.
31.
Dec
,
J. E.
,
Yang
,
Y.
, and
Dronniou
,
N.
,
2011
, “
Boosted HCCI-Controlling Pressure-Rise Rates for Performance Improvements Using Partial Fuel Stratification With Conventional Gasoline
,”
SAE Int. J. Engines
,
4
(
1
), pp.
1169
1189
.
32.
Van Dam
,
N.
,
Kalvakala
,
R. K.
,
Boink
,
F.
,
Yue
,
Z.
, and
Som
,
S.
,
2019
, “
Sensitivity Analysis of Fuel Physical Property Effects on Spark Ignition Engine Performance
,”
Proceedings of the ASME 2019 Internal Combustion Engine Division Fall Technical Conference
,
Chicago, IL
,
Oct. 20–23
,
V001T02A005
,
ASME
.
You do not currently have access to this content.