Phenomenological modeling of combustion and NOx emissions ...
Model-based Calibration using Coupled Hydraulic and ... · Combustion Injection and mixture...
Transcript of Model-based Calibration using Coupled Hydraulic and ... · Combustion Injection and mixture...
Model-based Calibration using Coupled Hydraulic and Combustion Simulation
2016 North American GT Conference 2016
Monday, November 14th 2016, Plymouth, Michigan
Dennis Backofen, Laura Wöhlert, Dr.-Ing. Reza Rezaei, Benjamin Tilch
Agenda
© IAV · 11/2016 · 1DB · MD-F2
• Reverse engineering for hydraulic simulation
• 1D injector model
• Physical combustion model
• Methodical approach
• Results
• Control chamber geometry
• Nozzle discharge coefficient
• Conclusion
2
Directly from the tier 1
Reverse Engineering
How to get a 1D-simulation model
Black Box
+ immediate start-up
- Black-box model
- No ability to change
the model parameters
- No model for
predictive work
3
Reverse engineering+ Fully configurable 1D
model
+ Model usable for
predictive work
+ Understanding of the
functionality
- Effort to determine the
important geometrical
values
Distructive dismounting
Non-distructive dismounting
CT-Analysis
…
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1D Simulation – Reverse Engineering
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Data collection
Destructive dismounting of the
component
Non-destructive dismounting of the component
Use of technical drawings e.g. CAD data
(ProE, Catia, Solid Edge, etc.)
Use of analog/digital measuring technologies
Optical analysis (microscope,
computer tomography)
Determination of characterstic numbers (e.g. spring
characteristic)
4
Nozzle flow, injection
rate and amount
Nozzle jet force
penetration, spray angle,
spray surface,
droplet size, droplet
distribution, droplet velocity
vaporization rate
Needle lift
Line pressure
Leakage
Rail pressure
Pump torque
Pressure at the
pump outlet
Pump flow
1D Simulation – Reverse Engineering
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Validation with measured data
Depending on rail pressure, counter-pressure, control duration, fuel (gasoline, diesel,
alt. fuels, gas, bad fuels), control strategy (single/multi-injection, etc.)
Valve lift
Leakage
Current and voltage to
control the injector
5
1D Injector Model
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Injector Model Specifications
Application area Commercial vehicle
Number of nozzle holes 8
QStat 2460 cm³/60s @100
bar
ma
ss p
er
str
oke
0
actuation duration
Gaincurves at constant rail pressure
x = Simulation
= 100 MPa (measurement)
= 150 MPa (measurement)
Good correlation between simulation and measurement results
6
Simulation of the Solenoid Actuation
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Time [ms]
Curr
en
t[A
]In
jectio
nR
ate
[m
g/m
s]
Measurement
Simple solenoid model
New solenoid model
• Simple solenoid model doesn‘t show the same time behaviour like the real injector
• Time delays in the opening and closing phase because of losses (e.g. eddy
current) can‘t be modeled
• Exact modelling of time delays are important e.g. for the combustion simulation
• Influence of the solenoid actuation is more intensive with GDI injectors
New solenoid model considers the time
delays during the opening and closing
phase of the injector.
7
Modeling Approaches of the Combustion ModelModel Structure
Gas Exchange
Simulation
(GT Power)
• The developed phenomenological combustion model is used for engine process
simulation and coupled with a GT POWER gas exchange model for intake flow
simulation.
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IAV Combustion Model
Injection Rate Module
Mixture Preparation Module
Turbulent Kinetic Energy Module
Ignition Module
Combustion Module
8
Application ExamplesIAV Combustion Model
IAV uses its own combustion model for 1D engine simulation or for the
physically-based development or calibration of engine control strategies.
MotivationApplications of the physical combustion model
Ignition and combustion
modeling
Engine Process
Simulation (1D)
Emission
Calculation (NOx)
Model-Based
Calibration
Basis for Dual-Fuel
Combustion
Injection and mixture
formation modeling
• The phenomenological combustion model was
developed at IAV (see SAE 2012-01-1065) and is
based on physical modeling of in-cylinder processes
such as Injection, ignition, and premixed and diffusive
combustion.
• Further development of the combustion model and a
novel NOx reaction kinetics are published in.
Phenomenological modeling of combustion and NOx
emissions using detailed tabulated chemistry methods in
diesel engines. International Journal of Engine Research
Physically-Based
Engine Control
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Methodical Approach
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Analysis of the change of design parameters during lifetime of a diesel injector
Smaller outlet diameter of the control chamber
Smaller inlet diameter of the control chamber
Smaller discharge coefficient
of the nozzle holes
Deposits
at the
throttles
Coking nozzle holes
Multiple Injection, without
tracking of the fuel amount/
BR50%
Multiple/single injection,
with & without tracking of
the fuel amount/BR50%
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Variation of Control Chamber Geometry
Smaller inlet diameter → early opening of the
nozzle holes and a higher injection rate especially in the pre-injection
Later closing of the nozzles holes → more intensive premixed combustion and slightly
higher and longer diffusion combustion
Smaller outlet diameter→ delay of the nozzle opening and earlier closing of the nozzles
holes → less premixed combustion and decrease of the diffusion combustion
© IAV · 11/2016 · 1DB · MD-F2
Inje
ction R
ate
[m
g/m
s]
0
20
40
60
80
100
120
Crank Angle [deg]
-10 0 10 20 30
Smaller inlet diameter contol chamber Smaller outlet diameter control chamber Standard
Heat
Rele
ase R
ate
(E
nerg
y p
er
Degre
e)
[J/d
eg]
-50
0
50
100
150
200
250
300
350
400
450
500
Crank Angle [deg]
-10 0 10 20 30 40 50 60 70 80 90 100
Smaller inlet diameter contol chamber Smaller outlet diameter control chamber Standard
More intense influence of the outlet diameter on the injection rate and combustion
process
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NOxOutput
Power
ppm kW
Standard 1102 55.06
Smaller diameter inlet control chamber 1322 58.46
Smaller diameter outlet control chamber 664 47.63
Def. Operation point
Variation of Nozzle Discharge Coefficient
Inje
ction R
ate
[m
g/m
s]
0
20
40
60
80
100
120
Crank Angle [deg]
-10 0 10 20 30
Standard Smaller nozzle-cd-value
Heat
Rele
ase R
ate
(E
nerg
y p
er
Degre
e)
[J/d
eg]
-50
0
50
100
150
200
250
300
350
400
450
500
Crank Angle [deg]
-10 0 10 20 30 40 50 60 70 80 90 100
Standard Smaller nozzle-cd-value
No influence on the the pre-injection and premixed combustion by decreasing the
nozzle discharge coefficient
Significant influence on the maximum injection rate and burning duration by decreasing
the nozzle discharge coefficient
NOxOutput
Power
ppm kW
Standard 1102 55.06
Lower cd-value nozzle holes 607 46.25
Def. Operation point
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Variation of Nozzle Discharge Coefficient and Control of the Injected Mass/BR50%
Inje
cti
on
Rate
[m
g/s
]
0
20
40
60
80
100
120
Crank Angle [°CA ATDC]
-10 0 10 20 30
Cyli
nd
er
Pre
ssu
re [
bar]
100
120
140
160
180
200
Pi = 44.0 kW
Bu
rn R
ate
[m
g/d
eg
]
0
2
4
6
8
10
12
14
16
Crank Angle [°CA ATDC]
-10 0 10 20 30
BR50%
11.1 °CA ATDC
cd = 0.88 (216 mg)
13
© IAV · 11/2016 · 1DB · MD-F2
Reduction of the nozzle discharge coefficient leads to a decreasing of the
maximum injection rate and reduction of the maximum cylinder pressure or
the burning rate and power respectively (12 %)
Variation of Nozzle Discharge Coefficient and Control of the Injected Mass/BR50%
Inje
cti
on
Rate
[m
g/s
]
0
20
40
60
80
100
120
Crank Angle [°CA ATDC]
-10 0 10 20 30
Cyli
nd
er
Pre
ssu
re [
bar]
100
120
140
160
180
200
Pi = 44.0 kW
Pi = 38.9 kW (D 11,8%)
Bu
rn R
ate
[m
g/d
eg
]
0
2
4
6
8
10
12
14
16
Crank Angle [°CA ATDC]
-10 0 10 20 30
BR50%
11.1 °CA ATDC 11.0 °CA ATDC
cd = 0.88 (216 mg)
cd = 0.70 (192 mg)
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© IAV · 11/2016 · 1DB · MD-F2
Variation of Nozzle Discharge Coefficient and Control of the Injected Mass/BR50%
Tracking the injected mass by increasing the energizing time of the injector
leads to a longer burning duration and a performance loss of 1.8%
Inje
cti
on
Rate
[m
g/s
]
0
20
40
60
80
100
120
Crank Angle [°CA ATDC]
-10 0 10 20 30
Cyli
nd
er
Pre
ssu
re [
bar]
100
120
140
160
180
200
Pi = 44.0 kW
Pi = 38.9 kW (D 11,8%) Pi = 43.3 kW (D 1,8%)
Bu
rn R
ate
[m
g/d
eg
]
0
2
4
6
8
10
12
14
16
Crank Angle [°CA ATDC]
-10 0 10 20 30
BR50%
11.1 °CA ATDC 11.0 °CA ATDC 12.0 °CA ATDC
cd = 0.88 (216 mg)
cd = 0.70 (192 mg) cd = 0.70 (216 mg), ET
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© IAV · 11/2016 · 1DB · MD-F2
Longer energizing time can track the power (increasing fuel consumption);
the BR50% changes slightly more
Variation of Nozzle Discharge Coefficient and Control of the Injected Mass/BR50%
Inje
cti
on
Rate
[m
g/s
]
0
20
40
60
80
100
120
Crank Angle [°CA ATDC]
-10 0 10 20 30
Cyli
nd
er
Pre
ssu
re [
bar]
100
120
140
160
180
200
Pi = 44.0 kW
Pi = 38.9 kW (D 11,8%) Pi = 43.3 kW (D 1,8%) Pi = 44.0 kW
Bu
rn R
ate
[m
g/d
eg
]
0
2
4
6
8
10
12
14
16
Crank Angle [°CA ATDC]
-10 0 10 20 30
BR50%
11.1 °CA ATDC 11.0 °CA ATDC 12.0 °CA ATDC
12.2 °CA ATDC
cd = 0.88 (216 mg)
cd = 0.70 (192 mg) cd = 0.70 (216 mg), ET cd = 0.70 (220 mg), ET , Pi = konst.
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© IAV · 11/2016 · 1DB · MD-F2
The same BR50% can be realized by an earlier injection start (fuel
consumption decreases)
Variation of Nozzle Discharge Coefficient and Control of the Injected Mass/BR50%
Cyli
nd
er
Pre
ssu
re [
bar]
100
120
140
160
180
200
Pi = 44.0 kW
Pi = 38.9 kW (D 11,8%) Pi = 43.3 kW (D 1,8%) Pi = 44.0 kW Pi = 44.0 kW
Inje
cti
on
Rate
[m
g/s
]
0
20
40
60
80
100
120
Crank Angle [°CA ATDC]
-10 0 10 20 30
Bu
rn R
ate
[m
g/d
eg
]
0
2
4
6
8
10
12
14
16
Crank Angle [°CA ATDC]
-10 0 10 20 30
BR50%
11.1 °CA ATDC 11.0 °CA ATDC 12.0 °CA ATDC
12.2 °CA ATDC 11.1 °CA ATDC
cd = 0.88 (216 mg)
cd = 0.70 (192 mg) cd = 0.70 (216 mg), ET cd = 0.70 (220 mg), ET , Pi = konst.
cd = 0.70 (219 mg), ET , Pi = BR50% = const.
17
© IAV · 11/2016 · 1DB · MD-F2
Tracking the injected mass by increasing the rail pressure leads to a similar injection
and burning rate compared to the original cd value
Compensation of the lower cd value by increasing the rail pressure is more efficient
(0.9%) than increasing the control duration
Variation of Nozzle Discharge Coefficient and Control of the Injected Mass/BR50%
Inje
cti
on
Rate
[m
g/s
]
0
20
40
60
80
100
120
Crank Angle [°CA ATDC]
-10 0 10 20 30
Cyli
nd
er
Pre
ssu
re [
bar]
100
120
140
160
180
200
Pi = 44.0 kW
Pi = 38.9 kW (D 11,8%) Pi = 43.3 kW (D 1,8%) Pi = 44.0 kW Pi = 44.0 kW
Pi = 43.7 kW (D 0,9%)
Bu
rn R
ate
[m
g/d
eg
]
0
2
4
6
8
10
12
14
16
Crank Angle [°CA ATDC]
-10 0 10 20 30
BR50%
11.1 °CA ATDC 11.0 °CA ATDC 12.0 °CA ATDC
12.2 °CA ATDC 11.1 °CA ATDC 10.8 °CA ATDC
cd = 0.88 (216 mg)
cd = 0.70 (192 mg) cd = 0.70 (216 mg), ET cd = 0.70 (220 mg), ET , Pi = konst.
cd = 0.70 (219 mg), ET , Pi = BR50% = const. cd = 0.70 (216 mg), pRail
18
© IAV · 11/2016 · 1DB · MD-F2
A higher increase of the rail pressure leads to the same power
Variation of Nozzle Discharge Coefficient and Control of the Injected Mass/BR50%
Inje
cti
on
Rate
[m
g/s
]
0
20
40
60
80
100
120
Crank Angle [°CA ATDC]
-10 0 10 20 30
Cyli
nd
er
Pre
ssu
re [
bar]
100
120
140
160
180
200
Pi = 44.0 kW
Pi = 38.9 kW (D 11,8%) Pi = 43.3 kW (D 1,8%) Pi = 44.0 kW Pi = 44.0 kW
Pi = 43.7 kW (D 0,9%) Pi = 44.0 kW
Bu
rn R
ate
[m
g/d
eg
]
0
2
4
6
8
10
12
14
16
Crank Angle [°CA ATDC]
-10 0 10 20 30
BR50%
11.1 °CA ATDC 11.0 °CA ATDC 12.0 °CA ATDC
12.2 °CA ATDC 11.1 °CA ATDC 10.8 °CA ATDC 10.8 °CA ATDC
cd = 0.88 (216 mg)
cd = 0.70 (192 mg) cd = 0.70 (216 mg), ET cd = 0.70 (220 mg), ET , Pi = konst.
cd = 0.70 (219 mg), ET , Pi = BR50% = const. cd = 0.70 (216 mg), pRail cd = 0.70 (219 mg), pRail , Pi = konst.
19
© IAV · 11/2016 · 1DB · MD-F2
Delaying the beginning of the injection leads to the same BR50%
Variation of Nozzle Discharge Coefficient and Control of the Injected Mass/BR50%
Inje
cti
on
Rate
[m
g/s
]
0
20
40
60
80
100
120
Crank Angle [°CA ATDC]
-10 0 10 20 30
Cyli
nd
er
Pre
ssu
re [
bar]
100
120
140
160
180
200
Pi = 44.0 kW
Pi = 38.9 kW (D 11,8%) Pi = 43.3 kW (D 1,8%) Pi = 44.0 kW Pi = 44.0 kW
Pi = 43.7 kW (D 0,9%) Pi = 44.0 kW Pi = 44.0 kW
Bu
rn R
ate
[m
g/d
eg
]
0
2
4
6
8
10
12
14
16
Crank Angle [°CA ATDC]
-10 0 10 20 30
BR50%
11.1 °CA ATDC 11.0 °CA ATDC 12.0 °CA ATDC
12.2 °CA ATDC 11.1 °CA ATDC 10.8 °CA ATDC 10.8 °CA ATDC
11.1 °CA ATDC
cd = 0.88 (216 mg)
cd = 0.70 (192 mg) cd = 0.70 (216 mg), ET cd = 0.70 (220 mg), ET , Pi = konst.
cd = 0.70 (219 mg), ET , Pi = BR50% = const. cd = 0.70 (216 mg), pRail cd = 0.70 (219 mg), pRail , Pi = konst. cd = 0.70 (219 mg), pRail , Pi = BR50% = const.
20
© IAV · 11/2016 · 1DB · MD-F2
Conclusion
By coupling a detailed 1D injector model and the IAV combustion model, it was
possible to analyse the influence of changing important design parameters:
• Outlet diameter of the control chamber has a more sensitive influence on the
combustion than the inlet diameter
• Changing the cd value of the nozzles shows only influences on the main injection
• Tracking the rail pressure for compensating the injected mass while the cd value
decreases is more efficient than increasing the control duration (constant power)
• Coupling the hydraulic and combustion 1D simulation represents an efficient tool
for the developing process of injection systems and burning processes.
• A detailed injector model could be very helpful, to simulate the real combustion
behaviour e.g. at multiple injection operation.
21
Thank you very much!
Dr.- Ing. Dennis Backofen
IAV GmbH
Nordhoffstraße 5, 38518 Gifhorn
Telefon: +49 5371 805-1587