Direct injection of natural gas into the cylinder of spark ignition (SI) engines has shown a great potential to achieve the best fuel economy and reduced emission levels. Since the technology is rather new, in-cylinder flow phenomena have not been completely investigated. In this study, a numerical model has been developed in AVL FIRE software to perform an investigation of natural gas direct injection into the cylinder of spark ignition internal combustion engines. In this regard, two main parts have been taken into consideration aiming to convert a multipoint port fuel injection (MPFI) gasoline engine to a direct injection natural gas (NG) engine. In the first part of the study, multidimensional simulations of transient injection process, mixing, and flow field have been performed. Using the moving mesh capability, the validated model has been applied to methane injection into the cylinder of a direct injection engine. Five different piston head shapes have been taken into consideration in the investigations. An inwardly opening single-hole injector has been adapted to all cases. The injector location has been set to be centrally mounted. The effects of combustion chamber geometry have been studied on the mixing of air-fuel inside the cylinder via the quantitative and qualitative representation of results. In the second part, an investigation of the combustion process has been performed on the selected geometry. The spark plug location and ignition timing have been studied as two of the most important variables. Simulation of transient injection was found to be a challenging task because of required computational effort and numerical instabilities. Injection results showed that the narrow bowl piston head geometry is the most suited geometry for NG direct injection (DI) application. A near center position has been shown to be the best spark plug location based on the combustion studies. It has been shown that advanced ignitions timings of up to 50 degrees crank angle ( °CA) should be used in order to obtain better combustion performance.

References

References
1.
Chiodi
,
M.
,
Berner
,
H. J.
, and
Bargende
,
M.
,
2006
, “
Investigation on Different Injection Strategies in a Direct-Injected Turbocharged CNG-Engine
,” SAE Paper No. 2006-01-3000.
2.
Li
,
Y.
,
Kirkpatrick
,
A.
,
Mitchell
,
C.
, and
Willson
,
B.
,
2004
, “
Characteristic and Computational Fluid Dynamics Modeling of High-Pressure Gas Jet Injection
,”
ASME J. Eng. Gas Turbines Power
,
126
, pp.
192
197
.10.1115/1.1635398
3.
Huang
,
Z.
,
Shiga
,
S.
,
Ueda
,
T.
,
Nakamura
,
H.
,
Ishima
,
T.
,
Obokata
,
T.
,
Tsue
,
M.
, and
Kono
,
M.
,
2003
, “
Visualization Study of Natural Gas Direct Injection Combustion
,”
Proc. Inst. Mech. Eng., Part D (J. Automob. Eng.)
,
217
, pp.
667
676
.10.1243/09544070360692069
4.
Huang
,
Z.
,
Shiga
,
S.
,
Ueda
,
T.
,
Nakamura
,
H.
,
Ishima
,
T.
,
Obokata
,
T.
,
Tsue
,
M.
, and
Kono
,
M.
,
2003
, “
Basic Characteristics of Direct Injection Combustion Fuelled With Compressed Natural Gas and Gasoline Using a Rapid Compression Machine
,”
Proc. Inst. Mech. Eng., Part D (J. Automob. Eng.)
,
217
, pp.
1031
1038
.10.1243/095440703770383929
5.
Huang
,
Z.
,
Shiga
,
S.
,
Ueda
,
T.
,
Nakamura
,
H.
,
Ishima
,
T.
,
Obokata
,
T.
,
Tsue
,
M.
, and
Kono
,
M.
,
2003
, “
Correlation of Ignitability With Injection Timing for Direct Injection Combustion Fuelled With Compressed Natural Gas and Gasoline
,”
Proc. Inst. Mech. Eng., Part D (J. Automob. Eng.)
,
217
, pp.
499
506
.10.1243/095440703766518122
6.
Huang
,
Z.
,
Zeng
,
K.
,
Liu
,
B.
,
Liu
,
L.
,
Jiang
,
D.
,
Ren
,
Y.
, and
Wang
,
J.
,
2006
, “
Combustion Characteristics of a Direct-Injection Natural Gas Engine Under Various Fuel Injection Timings
,”
Appl. Therm. Eng.
,
26
, pp.
806
813
.10.1016/j.applthermaleng.2005.10.011
7.
Papageorgakis
,
G.
, and
Assanis
,
D. N.
,
1999
, “
Optimizing Gaseous Fuel-Air Mixing in Direct Injection Engines Using an RNG Based k-ε Model
,”
SAE Trans., J. Engines
,
107
, pp.
82
107
.10.4271/980135
8.
Han
,
Z.
, and
Reitz
,
R. D.
,
1995
, “
Turbulence Modeling of Internal Combustion Engines Using RNG k-ε Models
,”
Combust. Sci. Technol.
,
106
, pp.
267
295
.10.1080/00102209508907782
9.
Li
,
G.
,
Ouelette
,
P.
,
Dumitrescu
,
S.
, and
Hill
,
P. G.
,
1999
, “
Optimization Study of Pilot-Ignited Natural Gas Direct-Injection in Diesel Engines
,” SAE Paper No. 1999-01-3556.
10.
Abraham
,
J.
, and
Magi
,
V.
,
1997
, “
Computation of Transient Jets: RNG k-ε Model Versus Standard k-ε Model
,” SAE Paper No. 970885.
11.
Ouellette
,
P.
, and
Hill
,
P. G.
,
2000
, “
Turbulent Transient Gas Injections
,”
ASME J. Fluids Eng.
,
122
, pp.
743
753
.10.1115/1.1319845
12.
Abraham
,
J.
,
1997
, “
What is Adequate Resolution in the Numerical Computations of Transient Jets?
,” SAE Paper No. 970051.
13.
Mather
,
D. K.
, and
Reitz
,
R. D.
,
2002
, “
Modeling the Effects of Auxiliary Gas Injection on Diesel Engine Combustion and Emissions
,”
SAE Trans., J. Engines
,
109
, pp.
443
458
.10.4271/2000-01-0657
14.
Baratta
,
M.
,
Catania
,
E.
, and
Pesce
,
F. C.
,
2009
, “
Multidimensional Modeling of Natural Gas Jet and Mixture Formation in DI SI Engines: Development and Validation of a Virtual Nozzle Model
,”
Proceedings of the Internal Combustion Engine Division Technical Conference
, ICES 2009, pp.
583
596
.
15.
Baratta
,
M.
,
Catania
,
A. E.
, and
Pesce
,
F. C.
,
2011
, “
Multidimensional Modeling of Natural Gas jet and Mixture Formation in Direct Injection Spark Ignition Engines: Development and Validation of a Virtual Injector Model
,”
ASME J. Fluids Eng.
,
133
, p.
041304
.10.1115/1.4003877
16.
Andreassi
,
L.
,
Facci
,
A. I.
,
Krastev
,
V. K.
, and
Ubertini
,
S.
,
2010
, “
Multidimensional Modeling of Gaseous Injection: Analysis of an Impinging Jet
,”
Int. J. Heat Fluid Flow
,
31
, pp.
909
915
.10.1016/j.ijheatfluidflow.2010.05.013
17.
Baratta
,
M.
,
Catania
,
A. E.
,
Spessa
,
E.
,
Herrmann
,
L.
, and
Roessler
,
K.
,
2008
, “
Multi-Dimensional Modeling of Direct Natural-Gas Injection and Mixture Formation in a Stratified-Charge SI Engine With Centrally Mounted Injector
,” SAE paper No. 2008-01-0975.
18.
Kim
,
G. H.
,
Kirkpatrick
,
A.
, and
Mitchell
,
C.
,
2004
, “
Computational Modeling of Natural Gas Injection in a Large Bore Engine
,”
ASME J. Eng. Gas Turbines Power
,
126
, pp.
656
664
.10.1115/1.1762906
19.
Yadollahi
,
B.
, and
Boroomand
,
M.
,
2011
, “
The Effect of Piston Head Geometry on Natural Gas Direct Injection and Mixture Formation in a SI Engine With Centrally Mounted Single-Hole Injector
,” SAE paper No. 2011-01-2448.
20.
Yadollahi
,
B.
, and
Boroomand
,
M.
,
2012
, “
A Numerical Investigation of Combustion Chamber Geometry Effects on Natural Gas Direct Injection Properties in a SI Engine With Centrally Mounted Multi-Hole Injector
,”
Proceedings of the Internal Combustion Engine Division Technical Conference
, ICES2012.
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