Post on 19-Jul-2018
SIMULATION FOR FUNCTION DEVELOPMENTGT POWER
“IN THE LOOP”
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.2
Usage of GT Power during the SW development process
Content
1. Introduction
1. What are the reasons to use GT Power ?
2. How was GT Power used ?
2. Proceeding
1. System investigation
2. Concept development
3. SW validation with co-simulation
4. Engine calibration (Three Pressure Analysis - TPA)
3. Conclusion and perspectives
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.3
Introduction
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.4
Introduction
Benefits:
development time: decoupling of engine and software development cycles
using GT Power for the first phases before “final confirmation” on engine.
development cost: GT Power less expensive than testbench …
the risks: wrong initial assumptions have less impact on project schedule
In the other hand: time and cost to build up the GT model !
SW development cycle
Engine development cycle
Engine ready
for testing
Engine ready
for testing
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.5
Introduction
Simulation with GT Power can be used instead of engine testbench for:
1. System investigation: analyze the system behaviour and physical tendencies
2. SW development:
- Concept phase: evaluate the system modelling / tools: MAPFIT or MOCA
- Implementation phase: SW validation via co-simulation / tools: Ascet and INTECRIO
3. SW calibration:
- Get unmeasurable data at the testbench (residual gas fraction, air speed ...) / TPA
- Reduce the testbench measurement points (DoE – Design Of Experiment)
Tradeoff GT model development cost / benefits
• From investigation phase to SW calibration, the use of simulation tools depends
on the model accuracy !
• For one single project, expensive / For many projects (reuse), high potential
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.6
Proceeding
VCR : Variable
Compression Ratio
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.7
Step 1: System investigation
System: Air Path
Topic: Charge determination
Bosch develops a model based engine
charge determination. This model covers
the usual range of engine operation.
However, with new technologies, the air
path variability increases, and the model
implemented in ECU software has to be
extended to these new degrees of freedom
and operation area.
Step 1: System investigation
How does the system behave ?
GT Power is used to get a better feeling of
the charge behaviour and give some input
for the concept development phase.
VVT : Variable Valve Timing
Variable Intake
Geometry : flaps,
trumpets, etc.
VVL : Variable Valve Lift
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.8
Step 1: System investigation
What is a charge determination model ?
Bosch ECU software implements a charge determination physical model
• Calculation of the fuel quantity to be injected
• Estimation of the engine torque
• Control of the charge and the boost pressure
• Transitions between injection modes, and to CDA (Cylinder DeActivation)
Question: How do new technologies impact the engine charge ?
Intake VVT position
Intake manifold pressure (Throttle and Wastegate)
VVL, VCR, swirl flaps, etc.
Exhaust VVT position
Exhaust manifold pressure
Modelled
engine
charge
Charge
determination
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.9
Step 1: System investigation
Analysis of the
valves behaviour
Variation of the
cylinder air filling
The GT Power simulations help to understand the system behaviour.
This knowledge is necessary to define a new concept, a new model.
GT Power simulations with variation of the
intake valve timing and other parameters
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.10
Step 2: Concept validation
Objective: to check whether the new SW model of
the charge determination is good or not, a Design of
Experiments (DoE) has been simulated on GT Power
to collect some points.
DoE: >2000 operating points, >4 degrees of freedom
• Engine speed
• Intake manifold pressure
• Intake and exhaust valve timing
• Valve lift, variable compression ratio, swirl flaps, etc.
Question: How to compare the charge model from the
ECU software to the measured one in GT simulations ?
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.11
Step 2: Concept validation
Simulation of different
engine operation points
Model design
Engine Model
GT Power
Calibration tool
MAPFIT(Bosch internal tool)
Charge Model
Ascet(ETAS tool)
Optimization tool, used to
calibrate the maps and curves
SW design and
code generation
Simulation data
A first design of the charge determination model is made in Ascet.
The model algorithm is used by an optimization tool to calibrate the maps
and curves based on the simulation results from GT Power.
The correlation results, and the analysis of the shape of curves and maps,
inform whether the concept is representative enough of the system or not.
After some recursion, the model is improved, ready for implementation.
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.12
Step 3: SW validation
After the concept validation, the SW functions are implemented in Ascet
to generate embedded code.
In order to save some time at the testbench, it is suitable to test the
generated code and detect implementation bugs GT Power can be
coupled to the SW functions in a co-simulation environment.
Step by step validation of model physical values.
SensorsEstimated charge
Desired charge
Measured charge
Ascet
ECU SW functionsGT Power
System model
Charge model
Charge
controller
Engine model
Validation of the
charge model
Validation of the
charge controller
Actuators
setpoints
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.13
Step 3: SW validation
With co-simulation, stationary and transient phases are analyzed
Interface (signals)
GT Power / Ascet Environment that synchronizes the SW functions
simulation and GT Power (via Simulink)SW functions
SIMULINK
Engine
model
INTECRIOASCET
Combination of two co-simulation environments
• Coupling Ascet / Simulink via Intecrio (master)
• Coupling Simulink / GT Power (slave)
Simulink used as interface between the ECU
functions (Ascet) and the engine (GT Power)
Intake manifold pressure(testbench measure)
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.15
Step 4: Three Pressure Analysis (TPA)
Target: Use testbench measurements to validate the simulation model
and calculate unmeasurable values with the GT Power engine model.
Cylinder pressure(testbench measure)
Exhaust manifold pressure(testbench measure)
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.16
Step 4: TPA Results
Valv
e L
ift
[mm
]
0
2
4
6
8
10
12
14Inlet
Exhaust
Fitted_Measured
Simulated
Valv
e L
ift
[mm
]
02468101214
Cylin
der
Pre
ssure
Cylin
der-
01
[bar]
010203040506070
Cyl1LHV 0.98
CA [deg]
-100-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Cylin
der
Pre
ssure
Cylin
der-
04
[bar]
010203040506070
Cyl4LHV 0.92
Valv
e L
ift
[mm
]
02468101214
Cylin
der
Pre
ssure
Cylin
der-
01
[bar]
0
10
20
30
40
50
60
70
CA [deg]
-400 -300 -200 -100 0 100 200 300 400
Cyl1LHV 0.98
Cylinder 1
Cylinder 4
TPA has been done for
over 2000 operating points
Accuracy of most points
has been good enough to
use the results
New data like residual gas
portion, better cylinder
pressure indication, etc.,
are used for the engine
calibration
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.17
Conclusion and Perspectives
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.18
Conclusion
GT Power can be used all along the software development cycle.
This proceeding allows to decouple the software development milestones
from the hardware (engine) development ones.
The two questions helping to decide to use GT Power or not:
• How accurate does the GT model need to be ?
• What is the related development cost compared to the benefits ?
In the perspective of the study, GT Power helped to work on different
topics, improving the SW maturity before the testbench sessions:
• The charge determination model
• The charge control using innovative technologies like VVL, VCR, etc.
GT Power "in the loop"
Bosch Engineering | BEG France | 17/05/2017
© Robert Bosch GmbH 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.19
Perspectives
Enhanced ECU software maximizes the potential of new engine
technologies: CO2 reduction, performance, dynamic
• GT Power is a relevant tool to develop such enhanced features
Reducing project cost by investing in system modelling
• Hardware test facilities are expensive
• No engine failure risks in simulation
• The more accurate the model is, the more development steps it could support
o For the ECU charge determination evaluation, the engine geometry is enough
o For BSFC optimization, a good combustion model is necessary
• In the end, the real system is the final judge… but could be less and less
necessary for the software development purposes !