stuttgart.de transient and map -based driving cycle ...stuttgart.de transient and map -based driving...
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Transient and MapTransient and Map--Based Driving Cycle Based Driving Cycle Calculation with GTCalculation with GT--SUITESUITE
GT-User Conference9th November 2009, Frankfurt Airport
Dipl.-Ing. Andreas Schmid, IVK University StuttgartDr.-Ing. Michael Grill, FKFS
Dipl.-Ing. Hans-Jürgen Berner, FKFS
Prof. Dr.-Ing. Michael Bargende, FKFS
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1. Introduction2. GT-Suite Model3. Transient Simulation4. Map-based Simulation5. Comparison6. Summary
OverviewOverview
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1. Introduction2. GT-Suite Model3. Transient Simulation4. Map-based Simulation5. Comparison6. Summary
OverviewOverview
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Calculating the expected fuel consumption of a new vehicle in driving cycles is major simulation goal
Map Based Simulation Transient Simulation
Kinematic Dynamic Dynamic
IntroductionIntroduction
Neural Network
Dynamic
Driving Cycle Calculation
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Dynamic Map-based simulation:• Engine fuel consumption and emissions are measured or simulated at
specific operation points (i.e. BMEP 2bar / 2000 RPM)
• Maps are used as interpolation basis
Dynamic transient simulation:
• Direct operation of a GT-POWER engine model in a driving cycle simulation
• No steady state conditions
IntroductionIntroduction
Neural Networks:
• Training neural networks in respect to different simulation boundary conditions (Temperature, Ignition Point….)
• Steady state conditions
complexity
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de IntroductionIntroduction
• Comparison of map-based and transient simulation of a SI-Engine
Comparison Basis:
Why not Neural Networks?:
• Reasonable boundary conditions?
Inlet Temperatures:
20 – 60°C ? Resolution?
Engine Knock? �Ignition Point Variation
External EGR-Rates? Inlet Cam Timing Variation?
Outlet Cam Timing Variation?Enrichment?
….
• Explosion of neural network training points
• No time advantage using neural networks when considering future simulation needs!
Turbine response?
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1. Introduction2. GT-Suite Model3. Transient Simulation4. Map-based Simulation5. Comparison6. Summary
OverviewOverview
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Highly modular GT-Suite Model is used
• Easy exchange of engine Model
� GT-Power engine model or map based model
• Different cars possible
GTGT--Suite ModelSuite Model
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1. Introduction2. GT-Suite Model3. Transient Simulation4. Map-based Simulation5. Comparison6. Summary
OverviewOverview
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• GT-Power Model of 1.8l DI-SI engine with a single turbocharger is used
• Model is integrated in the modular GT-Suite Model
• Acceleration pedal position is directly applied as “throttle signal”
• Crank angle of 50% burn point is adjusted at 8 °CA after FTDC
• A predictable burn-rate model is used (EGR, Geometry etc.)
• Warm-up strategies are not considered (comparison!)
• Very difficult to control � Main ECU functions have to be considered
� Long simulation duration ~ approx. 5-7 days for NEDC
Overview
Transient SimulationTransient Simulation
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1. Introduction2. GT-Suite Model3. Transient Simulation4. Map-based Simulation5. Comparison6. Summary
OverviewOverview
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• Identical GT-Power Model of 1.8l DI-SI engine with a single turbocharger is used
• Engine fuel map is calculated at the whole operating range of the engine
• “hot” engine conditions are used
• Simulated fuel consumption is integrated in map-based GT-Drive engine state object
• Standard GT-interpolation in fuel-maps are used
� Short simulation duration of driving-cycle calculation but engine map calculation is approx. 2-3 days, even at basic simulation conditions!
Overview
MapMap--based Simulationbased Simulation
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1. Introduction2. GT-Suite Model3. Transient Simulation4. Map-based Simulation5. Comparison6. Summary
OverviewOverview
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Basic conditions of simulation:
• Comparison cycle: NEDC
• Warm-up strategies are not considered
• No enrichment at start-up is used
• Automatic transmission strategy is used for best fuel economy
• identical medium-sized car is used for both simulation
ComparisonComparison
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Veh
icle
Spe
ed [k
m/h
]
0
20
40
60
80
100
120
140
Time [s]0 200 400 600 800 1000 1200
Transient simulation Map based simulation
Vehicle SpeedVehicle Speed
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Fue
l Con
sum
ptio
n [k
g/h]
-1
0
1
2
3
4
5
6
7
8
9
10
Time [s]0 200 400 600 800 1000 1200
Transient simulation Map based simulation
Fuel Consumption 1Fuel Consumption 1
Apparent Deviations!
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Fue
l Con
sum
ptio
n [l/
100k
m]
3
5
7
9
11
13
15
17
19
Time [s]0 200 400 600 800 1000 1200
Transient simulation Map based simulation
Fuel Consumption 2Fuel Consumption 2
Compensation over the NEDC!
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Tur
bine
Inle
t Tem
pera
tur
[K]
500
600
700
800
900
1000
1100
1200
1300
Time [s]0 200 400 600 800 1000 1200
Transient simulation
Temperature TurbineTemperature Turbine
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Tem
pera
tur
Cat
alyt
ic C
onve
rter
[K]
300
400
500
600
700
800
900
1000
1100
1200
Time [s]0 200 400 600 800 1000 1200
Transient simulation
Temperature Catalytic ConverterTemperature Catalytic Converter
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• Just small deviations in overall fuel consumption
• Deviations during simulation just have minor effect on overall fuel consumption because of compensation
Comparison results:
Surprising Results?
• NEDC is quite stationary
• Fuel consumption reacts linear � interpolation possible
� Identical Model � Same results!
ComparisonComparison
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• Warm-up strategies
• Emissions (especially NOx) nonlinear!
• Acceleration behavior of “Downsizing” engines
• Turbine response behavior
• Customer driving cycles with high engine loads
• CAI/HCCI simulation / high EGR
• Max. allowed temperature � transient necessary enrichment
• Min. allowed catalytic converter temperature over cycle
• Exhaust gas treatment strategies
….
� Transient simulation essential for future simulation needs!
Transient simulation necessary?
ComparisonComparison
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de Transient SimulationTransient Simulation
Veh
icle
Spe
ed [k
m/h
]
60
65
70
75
80
85
90
95
100
Time [s]0 1 2 3 4 5 6 7 8
BM
EP
[bar
]0
2
4
6
8
10
12
14
16
18
Cra
nk A
ngle
of 5
0% B
urn
Poi
nt [C
A]
0
5
10
15
20
25
30
35
40
Vehicle Speed BMEP Crank Angle of 50 Burn Point
Example: Acceleration 60 � 100 km/h - Supercharged SI-Engine with anti-knock control
Direct transient simulation
� “real”-World simulation!
Knock control
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1. Introduction2. GT-Suite Model3. Transient Simulation4. Map-based Simulation5. Comparison6. Summary
OverviewOverview
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• Comparison of map-based and transient NEDC simulation was realized
• Neural networks offer no time advantage if all reasonable boundary conditions for future engines are considered
• Only small deviations occur if no warm-up strategy is chosen
• Transient simulation duration is higher compared to map-based simulation if maps are existent
• Transient simulation is very difficult to handle
• But transient simulation offers an enormous application range
• For future simulation needs transient simulation is an essentialtool
SummarySummary
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Transient and MapTransient and Map--Based Driving Cycle Based Driving Cycle Calculation with GTCalculation with GT--SUITESUITE
GT-User Conference9th November 2009, Frankfurt Airport
Dipl.-Ing. Andreas Schmid, IVK University StuttgartDr.-Ing. Michael Grill, FKFS
Dipl.-Ing. Hans-Jürgen Berner, FKFS
Prof. Dr.-Ing. Michael Bargende, FKFS