Through comprehensive experimental and modeling efforts, this work unravels the underlying mechanisms governing flame development and misfire at advanced engine conditions that are representative of low-load and lean blow-out operations. Toward this, preliminary heat release, autoignition, and flame developing patterns are characterized, via a case study of n-heptane, at ultra-lean conditions in a well-controlled optical engine under various combustion modes including homogeneous charge compression ignition (HCCI), partially premixed combustion (PPC), and reactivity-controlled compression ignition (RCCI). Changes in preliminary heat release and flame developing patterns at three overall equivalence ratios (0.12, 0.18, and 0.24) are first characterized under the PPC mode. Flame development characteristics including flame areas and number of initial flame kernels at close-to-misfire conditions are further extracted and compared across the HCCI, RCCI, and three PPC modes, with two distinctive and one transition regimes identified. Further analyses indicate that sustainable flame development and misfire are largely controlled by the spatial distribution of local equivalence ratio (phi) and local temperature in the mixture, which dictate the initial flame kernel generation and the subsequent flame propagation through localized preliminary heat release and autoignition. Chemical kinetic modeling is also undertaken, using a recently updated gasoline chemistry model, in conjunction with a backpropagation neural network, where the predicted ignition delay map well captures the different regions of flame development. Further kinetic analysis and heat rate of production per reaction analysis corroborate the CH2O planar laser-induced fluorescence experiments and highlight the important chemical kinetics that govern the initial flame development patterns.

1.
Y.
Huang
and
V.
Yang
, “
Dynamics and stability of lean-premixed swirl-stabilized combustion
,”
Prog. Energy Combust. Sci.
35
,
293
(
2009
).
2.
V.
Raman
,
Q. L.
Tang
,
Y. Z.
An
,
H.
Shi
,
P.
Sharma
,
G.
Magnotti
,
J.
Chang
, and
B.
Johansson
, “
Impact of spray-wall interaction on the in-cylinder spatial unburned hydrocarbon distribution of a gasoline partially premixed combustion engine
,”
Combust. Flame
215
,
157
(
2020
).
3.
S. L.
Wang
,
X. D.
Zhu
,
L. M. T.
Somers
, and
L. P. H.
de Goey
, “
Effects of exhaust gas recirculation at various loads on diesel engine performance and exhaust particle size distribution using four blends with a research octane number of 70 and diesel
,”
Energy Convers. Manage.
149
,
918
(
2017
).
4.
M.
Stohr
,
R.
Sadanandan
, and
W.
Meier
, “
Experimental study of unsteady flame structures of an oscillating swirl flame in a gas turbine model combustor
,”
Proc. Combust. Inst.
32
,
2925
(
2009
).
5.
J. M.
Lourier
,
M.
Stohr
,
B.
Noll
,
S.
Werner
, and
A.
Fiolitakis
, “
Scale Adaptive Simulation of a thermoacoustic instability in a partially premixed lean swirl combustor
,”
Combust. Flame
183
,
343
(
2017
).
6.
Z. X.
Chen
,
N.
Swaminathan
,
M.
Stohr
, and
W.
Meier
, “
Interaction between self-excited oscillations and fuel-air mixing in a dual swirl combustor
,”
Proc. Combust. Inst.
37
,
2325
(
2019
).
7.
Z. G.
Zhang
,
D.
Guan
,
Y. Q.
Zheng
, and
G. N.
Li
, “
Characterizing premixed laminar flame-acoustics nonlinear interaction
,”
Energy Convers. Manage.
98
,
331
(
2015
).
8.
Y. Z.
An
,
V.
Raman
,
Q. L.
Tang
,
H.
Shi
,
J.
Sim
,
J.
Chang
,
G.
Magnotti
, and
B.
Johansson
, “
Combustion stability study of partially premixed combustion with low-octane fuel at low engine load conditions
,”
Appl. Energy
235
,
56
(
2019
).
9.
Q. L.
Tang
,
H. F.
Liu
,
M. K.
Li
, and
M. F.
Yao
, “
Optical study of spray-wall impingement impact on early-injection gasoline partially premixed combustion at low engine load
,”
Appl. Energy
185
,
708
(
2017
).
10.
F. S.
Liu
,
Z. J.
Shi
,
Z.
Zhang
,
Y. K.
Li
, and
C. H.
Sun
, “
Numerical study on critical ambient temperature for auto-ignition of the diesel spray under cold-start conditions
,”
Fuel
258
,
116191
(
2019
).
11.
Z. J.
Shi
,
F. S.
Liu
,
W. W.
Shang
,
Y. K.
Li
,
C. H.
Sun
, and
M.
Zhu
, “
Numerical study on the influence of injection pressure on the ignition and combustion of n-dodecane spray at cold-start conditions
,”
Fuel
264
,
116882
(
2020
).
12.
H. Y.
Chen
,
Z. J.
Shi
,
F. S.
Liu
,
Y.
Wu
, and
Y. K.
Li
, “
Non-monotonic change of ignition delay with injection pressure under low ambient temperature for the diesel spray combustion
,”
Energy
243
,
123017
(
2022
).
13.
G.
Bansal
and
H. G.
Im
, “
Autoignition and front propagation in low temperature combustion engine environments
,”
Combust. Flame
158
,
2105
(
2011
).
14.
C. S.
Yoo
,
Z. Y.
Luo
,
T. F.
Lu
,
H.
Kim
, and
J. H.
Chen
, “
A DNS study of ignition characteristics of a lean iso-octane/air mixture under HCCI and SACI conditions
,”
Proc. Combust. Inst.
34
,
2985
(
2013
).
15.
M. B.
Luong
,
Z. Y.
Luo
,
T. F.
Lu
,
S. H.
Chung
, and
C. S.
Yoo
, “
Direct numerical simulations of the ignition of lean primary reference fuel/air mixtures with temperature inhomogeneities
,”
Combust. Flame
160
,
2038
(
2013
).
16.
M. B.
Luong
,
G. H.
Yu
,
T. F.
Lu
,
S. H.
Chung
, and
C. S.
Yoo
, “
Direct numerical simulations of ignition of a lean n-heptane/air mixture with temperature and composition inhomogeneities relevant to HCCI and SCCI combustion
,”
Combust. Flame
162
,
4566
(
2015
).
17.
L. T.
Su
,
M.
Zhang
,
J. H.
Wang
, and
Z. H.
Huang
, “
Direct numerical simulation of DME auto-ignition with temperature and composition stratification under HCCI engine conditions
,”
Fuel
285
,
119073
(
2021
).
18.
C.
Xu
,
J. W.
Park
,
C. S.
Yoo
,
J. H.
Chen
, and
T. F.
Lu
, “
Identification of premixed flame propagation modes using chemical explosive mode analysis
,”
Proc. Combust. Inst.
37
,
2407
(
2019
).
19.
C.
Xu
,
A. Y.
Poludnenko
,
X. Y.
Zhao
,
H.
Wang
, and
T. F.
Lu
, “
Structure of strongly turbulent premixed n-dodecane-air flames: Direct numerical simulations and chemical explosive mode analysis
,”
Combust. Flame
209
,
27
(
2019
).
20.
K.
Aditya
,
A.
Gruber
,
C.
Xu
,
T. F.
Lu
,
A.
Krisman
,
M. R.
Bothien
, and
J. H.
Chen
, “
Direct numerical simulation of flame stabilization assisted by autoignition in a reheat gas turbine combustor
,”
Proc. Combust. Inst.
37
,
2635
(
2019
).
21.
O.
Schulz
,
T.
Jaravel
,
T.
Poinsot
,
B.
Cuenot
, and
N.
Noiray
, “
A criterion to distinguish autoignition and propagation applied to a lifted methane-air jet flame
,”
Proc. Combust. Inst.
36
,
1637
(
2017
).
22.
Y. C.
Zhou
,
C.
Zhang
,
X.
Han
, and
Y. Z.
Lin
, “
Monitoring combustion instabilities of stratified swirl flames by feature extractions of time-averaged flame images using deep learning method
,”
Aerosp. Sci. Technol.
109
,
106443
(
2021
).
23.
Z. Y.
Wang
,
C. F.
Song
, and
T.
Chen
, “
Deep learning based monitoring of furnace combustion state and measurement of heat release rate
,”
Energy
131
,
106
(
2017
).
24.
G. E.
Karniadakis
,
I. G.
Kevrekidis
,
L.
Lu
,
P.
Perdikaris
,
S. F.
Wang
, and
L.
Yang
, “
Physics-informed machine learning
,”
Nat. Rev. Phys.
3
,
422
(
2021
).
25.
Y.
Cui
,
H.
Liu
,
M.
Wen
,
L.
Feng
,
Z.
Ming
,
Z.
Zheng
,
T.
Fang
,
L.
Xu
,
X.-S.
Bai
, and
M.
Yao
, “
Optical diagnostics of misfire in partially premixed combustion under low load conditions
,”
Fuel
329
,
125432
(
2022
).
26.
M. K.
Le
,
S.
Kook
, and
E. R.
Hawkes
, “
The planar imaging of laser induced fluorescence of fuel and hydroxyl for a wall-interacting jet in a single-cylinder, automotive-size, optically accessible diesel engine
,”
Fuel
140
,
143
(
2015
).
27.
S.
Cheng
,
C.
Saggese
,
D.
Kang
,
S. S.
Goldsborough
,
S. W.
Wagnon
,
G.
Kukkadapu
,
K. W.
Zhang
,
M.
Mehl
, and
W. J.
Pitz
, “
Autoignition and preliminary heat release of gasoline surrogates and their blends with ethanol at engine-relevant conditions: Experiments and comprehensive kinetic modeling
,”
Combust. Flame
228
,
57
(
2021
).
28.
Z. K.
Wang
,
P.
Stamatoglou
,
M.
Lundgren
,
L.
Luise
,
B. M.
Vaglieco
,
A.
Andersson
,
M.
Alden
,
O.
Andersson
, and
M.
Richter
, “
Simultaneous 36 kHz PLIF/chemiluminescence imaging of fuel, CH2O and combustion in a PPC engine
,”
Proc. Combust. Inst.
37
,
4751
(
2019
).
29.
Z. Q.
Zheng
,
X. H.
Fang
,
H. F.
Liu
,
C.
Geng
,
Z.
Yang
,
L.
Feng
,
Y.
Wang
, and
M. F.
Yao
, “
Study on the flame development patterns and flame speeds from homogeneous charge to stratified charge by fueling n-heptane in an optical engine
,”
Combust. Flame
199
,
213
(
2019
).
30.
X. B.
Duan
,
M. C.
Lai
,
M.
Jansons
,
G. M.
Guo
, and
J. P.
Liu
, “
A review of controlling strategies of the ignition timing and combustion phase in homogeneous charge compression ignition (HCCI) engine
,”
Fuel
285
,
119142
(
2021
).
You do not currently have access to this content.