advanced physics-based cae solutions for optimizing fuels ...€¦ · k2 – fast response...
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confidential. © cmcl innovations, 2013
Advanced Physics-based CAE solutions for Optimizing Fuels, Combustion Modes and Emissions in modern ICEs
Dr. Amit Bhave cmcl innovations
UKTI’s Clean Technology Seminar 12 January 2013 Pune, India
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contents
• CAE at cmcl innovations
• kinetics & srm engine suite : predictive simulation
• practical application#1: Diesel engine optimisation
• practical application#2: Advanced SI engine
• practical application#3: fuel-engine correlations
• Q&A
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CAE at cmcl innovations
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target markets
- automotive, heavy duty and non-road powertrain
- fuels, feedstocks and clean energy
- chemical process industry
cmcl innovations
software | consulting | training
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CAE products for virtual engineering
srm engine suite – multi-award winning advanced IC engine fuels, combustion and emissions simulator
mod suite – model development suite, data
standardisation, uncertainty propagation,
parameter estimation, optimisation
kinetics – chemical kinetics mechanism builder, fuel models and emissions pathways analysis, reactor models for chemical industry,
CFD plugins – multi dimensional reactive flow dynamics
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CAE partner in collaborative R&D projects
LiLa – Library of Labs for remote experiments and virtual
laboratory in science and engineering
Role: Industrial partner
Technical: virtual laboratory for IC engine applications
Model Surrogates – High dimensional model reduction (HDMR)
Role: Project sponsor/coordinator
Technical: Surrogate model development, benchmarking and applications
TESBiC – Techno-Economic Study of Biomass to power with CO2 capture
Role: Project Lead/Coordinator
Technical: Model development, parameter estimation, optimisation
K2 – Fast response algorithms and real-world data coupling for non-road engines/machines
Role: Technical industrial partner
Technical: Surrogate model development, data mining, virtual engineering
C-FAST project: Carbon-negative fuels
Role: Project coordinator
Technical: Techno-economic engineering analysis and design
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our customers’ main challenges
Combustion
knock, misfire, ignition, low temperature combustion
Modern techniques
boosting exhaust gas residuals
multiple direct injection
Emissions
CO, uHCs, NOx, soot particles
(including number density
and composition)
Fuels
alternative fuels fuel development fuel reformation
kinetics & srm engine suite “Efficient Physics-based Predictive Insight into Fuels, Combustion and Emissions in modern ICE context”
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CAE application – an example
TRL: Technology Readiness Level
SRM: Stochastic Reactor Model
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kinetics & srm engine suite
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3D CFD software tools
In-cylinder optimisation
• CPU time days/cycle
• predictive combustion
• predictive emissions in
some cases
• limited by CPU time
modelling fuels, combustion and emissions
Stochastic Reactor Models
• CPU time seconds to minutes • predictive combustion and emissions • turbulence, heat transfer, MDI, EGR, fuel volatility
1D multi-cycle software tools
breathing, valve train and
engine optimisation
• CPU time seconds/cycle
• poor predictive combustion
• poor predictive emissions
• integration into 1D cycle tools • more efficient solution for combustion optimisation
• properly account for chemical kinetics i.e. ignition, extinction, misfire, flame propagation and emissions
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Combustion: Compression Ignition Direct Injection Port & Direct Injection Spark Ignition Low temperature combustion (HCCI, PCCI etc.)
Fuels: Gasoline, Diesel, bio-fuels, CNG etc., fuel blends Emissions: All regulated (PM, NOx, UHCs, CO) and unregulated Easy-to-use: Graphical interface Batch running, parallelised
Short CPU times Coupling with 3rd party tools
fuels, combustion and emissions
11
kinetics & srm engine suite
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different modes of combustion
Mode DISI advanced CIDI
SOI [aTDC] -100 -100 -2
EOI [aTDC] -90 -90 25
C.R. 11 15.0 15.0
PIVC [bar] 0.75 1.2 1.2
TIVC [K] 450 450 550
Fuel gasoline diesel diesel
Fuel [mg] 10.0 10.0 10.0
1500 RPM ~2.62BMEP 30% EGR
PCCI/LTC/HCCI CIDI DISI
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options for running the srm engine suite
1. either in a stand-alone mode that models engine breathing and closed volume portion of the engine cycle
OR
2. coupled with 1D engine cycle toolkits to account for engine environment: piping, turbochargers, EGR coolers etc.
OR
3. tabulated srm suite for real-time simulation with option 2.
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practical application#1: diesel engine optimisation
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CAT Diesel engine
1500 rpm
Same fuel concentration – 63mg
Single Injection
0 0.1 0.2 0.3 0.4 0.5 0.6 -10
-50
510
0
50
100
150
Ignition Timing [CAD aTDC]
EGR Mass [Fraction]
Manifold
Pre
ssure
[kP
a]
Injection Timing [CAD aTDC]
practical application#1: diesel engine optimisation
15
SAE 2011-01-1388
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in-cylinder pressure profile - I
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in-cylinder pressure profile - II
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in-cylinder pressure profile - III
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model-experiment
inconsistency
19
in-cylinder pressure profile - IV
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NOx emissions
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CO emissions
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• srm suite – a physics based simulation tool for optimisation
• at 0.3 EGR mass fraction
• parametric sweep of – Manifold pressure
– Injection timing
• Isolate their impact on heat release and emissions
0 0.1 0.2 0.3 0.4 0.5 0.6 -10
-50
510
0
50
100
150
Ignition Timing [CAD aTDC]
EGR Mass [Fraction]
Manifold
Pre
ssure
[kP
a]
Injection Timing [CAD
22
optimisation domain
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-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
Injection Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
45s per computation
Matrix of 88 – total computational time 66 minutes
23
interpolation / extrapolation
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Peak pressure [bar] CA50 [CAD]
2
22 44
4
66
6
88
8
10
10
12
12
15
15
18
18
20
20
22
22
25
25
Ignition Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
70
70
7070
80
80
8080
90
90
90
90
100
100
100
100
120
120
120
140
140
160
160
180
Ignition Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
2020
30
30
30
40
4040
50
50
50
60
60
70
70
80
80
90
90
100
100
110
110
120
120
130
140
140
Ignition Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
dp/dCAD [bar/ms]
0.40.4
0.4
0.425
0.425
0.45
0.450.45
0.475
0.4750.475
0.5
0.50.5
0.5250.525
0.525
0.55
0.550.55
0.575
0.5750.575
0.60.6
0.6
Ignition Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
Total equivalence ratio [-]
Injection Timing [CAD aTDC] Injection Timing [CAD aTDC]
Injection Timing [CAD aTDC] Injection Timing [CAD aTDC]
24
impact due to constraints
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NOx [ppm] CO [ppm]
10
1010
25
2525
50
50
75
75
100
100
125
125
150
150
175
175
200
200
225
250
300
350
Ignition Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
100100
100
300
300
300300 600600
600
600
900900
900
900
20002000
2000
4000
4000
8000
12000
2000
Ignition Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
5
5
5
55 10
10
10
20
20
20
50
50
100
100
10
200
400
200
5
Ignition Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
UHCs [ppm]
Injection Timing [CAD aTDC] Injection Timing [CAD aTDC]
Injection Timing [CAD aTDC] 25
Interpolation / extrapolation - emissions
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10
1010
25
2525
50
50
75
75
100
100
125
125
150
150
175
175
200
200
225
250
300
350
Ignition Timing [CAD aTDC]
Manifold
Pre
ssure
[kP
a]
-10 -8 -6 -4 -2 0 2 4 6 8 1020
30
40
50
60
70
80
90
100
110
Injection Timing [CAD aTDC]
NOx [ppm]
26
where to operate?
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impact of EGR
00.1
0.20.3
0.40.5 -10
-5
0
5
10
0
25
50
75
100
Injection Timing [CAD aTDC]
EGR [fr.]
Manifold
Pre
ssure
[kP
a]
EGR Injection timing [CAD aTDC]
Man
ifo
ld p
ress
ure
[kP
a]
• From 4 experimental data points – an educated estimate of the optimal operating point
• Using conventional CFD- months of CPU time
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practical application#2: DISI engines
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DISI engine mode
simulating cyclic variations turbulent flame speed varied significant impact on emissions
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SI combustion: “downspeeding”
intake pressure 2.2 bar, 1000rpm retarded ignition some cycles pre-ignited
oil-ignition was simulated
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GDI SI: soot size distribution
• Stratified operation improves fuel economy but increases in-cylinder fuel-rich pockets
• Fuel impingement and lack of mixing result in soot/particulate matter emissions
• Particle number emissions from
gasoline engines – pending regulations
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12.6 CAD ATDC 32.6 CAD ATDC 2.6 CAD ATDC
GDI SI: soot aggregates
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experiment simulation
SI-HCCI transients: mode switching
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practical application#3: fuel-engine correlations
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practical fuel modelling
Conventional fuels
(a) Research Octane Number (RON)
(b) Octane "Sensitivity" (RON – MON)
Tri-component surrogate fuels increase the robustness of practical fuel modelling as fuel sensitivity can also be simulated
fuel blends practical gasoline ethanol/gasoline blending biofuels & future fuels
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gasoline – fuel for advanced diesel engine ?
A 0.537 litre single cylinder diesel engine with a compression ratio of 15.8:1 operated using an 84 RON gasoline fuel. Bosch injectors were adopted with seven holes of 0.13mm diameter. Single injection SOI =-11.2 CAD aTDC, Triple injections a) 25% SOI @ -180 CAD aTDC, b) 15% @ - 76 CAD aTDC and main @ -7 CAD aTDC.
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multiple injection strategies
dp/dt [bar/CAD] burn duration [CAD]
NOx emissions [-] CO emissions [-] uHCs emissions [-]
~12 bar IMEP
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Experiments carried out by Shell
engine specification
38
Compression ratio (CR) 15.9:1 Displacement 0.537 l
Bore 88 mm Stroke 88.3 mm
Connection rod length 149 mm Inlet valve open (IVO) 362 CAD Inlet valve close (IVC) 595 CAD
Exhaust valve open (EVO) 143 CAD Exhaust valve close (EVC) 385 CAD
Speed 1200 RPM Manifold pressure 1.0 bar (a)
Manifold temperature 65 deg C Exhaust pressure 1.0 bar (a)
IMEP 4.0 bar Injection pressure 650 bar Equivalence ratio 0.370 Air mass flow rate 6.03 g/s
84 PRF n-heptane RON 84 0 MON 84 0
vol. % of iso-octane 84 0 vol. % of n-heptane 16 100
Density (g/cc) 0.682 0.632 C 7.83 7.0 H 17.67 16.0
LHV (MJ/kg) 44.4 44.6
Table 1 – Engine specification.
Table 2 – Engine operating point.
Table 3 – Fuel properties.
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example impact of fuel
Fuel Gasoline Diesel
SOI [aTDC] -8 -8
EOI [aTDC] -4 -4
1200 RPM
4bar iMEP
5% EGR
84PRF gasoline fuel – low PM
diesel fuel (n-heptane)
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summary
• kineticsTM & srm engine suite is a practical tool for assessing combustion efficiency, fuel consumption, and emissions in the development of improved ICEs fuelled with conventional and alternative fuels
• for multiple engine cycles-based analysis, 1D engine cycle tools are practical and can further add value if inhomogeneities and chemical kinetics is accounted
• it is always beneficial to minimise the number of model parameters thus, in turn, reducing the effort associated with parameter estimation (also termed as model calibration or model validation)
• optimisation and extrapolation based on physics-based models rather than purely statistical ones offers model robustness and hence more predictive capability.
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kinetics & srm engine suite applications
• emissions in 1D context • any fuel can be analysed • explore operating strategies • minimise emissions • meet engineering constraints • inform experiments • understand the key processes • steady state & transient