Modeling the Electrically Assisted Variable Speed (EAVS

Modeling the Electrically Assisted Variable
Speed (EAVS) Supercharger
Eaton Corporation—Vehicle Group
Brian Smith
Brandon Biller
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Overview of EAVS Technology
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EAVS System Development at Eaton
•
Hardware refinement
•
Gearbox design
•
eMotor selection
•
Supercharger
selection
•
Hardware validation
•
Flowbench testing
•
Performance
mapping
Bench
Testing
Modelin
g
Desig
n
•
Vehicle calibration
•
Data collection
•
Emission regulation
assessment
•
Concept demonstration
Testing
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•
System matching
•
Engine/ vehicle
performance
predictions
•
Controls development
•
Architecture trade
studies
3
Modeling Motivations
•
Application:
•
1.4L Base Engine, 23 bar BMEP, 95 kW/L
•
48V EAVS boosting/ mild hybrid system
•
1750 kg vehicle
•
Evaluate the performance, fuel efficiency, drivability—value proposition
•
Study state control strategies for EAVS operating modes
•
Study electrical demand & develop energy management strategy
•
Correlate to test vehicle & guide future improvements
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4
Engine Model Construction
• Started with 1.4L
turbocharged fast
running model
(FRM)
Show side by side of FRM baseline and
revised versions
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• Nearest match to
baseline I4 Ecotec
Cruze Eco Engine
5
FRM Model Conversation
• Removed
turbocharger
Show side by side of FRM baseline and
revised versions
Removed turbocharger
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6
FRM Model Conversation
• Incorporate
supercharger and
planetary system
Show side by side of FRM baseline and
revised versions
• Steady state
modeling - expand
torque curve
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7
FRM Model Conversation
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8
FRM Model Conversation
• Incorporate
operating mode
controller
• Improved transient
controls
• Validated electric
motor model
• Validated battery
model
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9
FRM Model Conversation
Increased
mass to
1750kg
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10
Event Manager
Robust Method for Supervisory State Control
Event Manager Template provides
supervisory control of the system to
determine operating mode
Operating
Mode Event
Manager
Operating Modes
1. Stopped, Engine Off
Throttle
Controller
Electric
Machine
Controller
2. Starting Engine
3. Idle
4. NA Engine Operation
IF-THEN-ELSE Templates govern the lower level
controllers based on the operating mode request from the
Event Manager
5. Boosted Engine
Operation
6. Generator
7. Torque Assist
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8. Brake Regeneration
11
Simulation Value
Study Emissions Cycles
• Understand most influential engine operating points
• Operating mode breakdown over emission cycles
• Balance electrical system state-of-charge
• Maximizing energy recuperation
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12
Vehicle Fuel Economy Results
Fuel Economy
Simulation (mpg)
Vehicle Dyno Test*
(mpg)
Percent Error (%)
FTP75
US06
HWFET
42.4
31.1
53.4
36.9**
30.1
53.4
13%
3.2%
0%
Battery State of Charge Initial = 90%
Simulation (%
SOC)
90.4
94.5
91.5
Vehicle Dyno Test
(% SOC)
91.0
92.5
87.0
*Standard regulatory emissions cycle testing at qualified 3rd party
**Vehicle start-stop system was not active on all opportunities for engine-off state during
actual test—a major contributor to higher fuel consumption & discrepancy
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13
Benefits of Model Development
• Powertrain systems architecture approach
• Influences & sensitivity of sub-system impacts on fuel
economy & performance better understood
• Capture transient effects and hybrid system influences
on cycles and real world driving
• Simulation leads decision making process for
hardware & vehicle design changes
• Value proposition construction and scenario iterations
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14
GT-Module Supports Customer Evaluation
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15
Conclusions
• GT-Suite model helps to lead the development of EAVS
technology at Eaton
• Simulation drastically reduces need for hardware iterations
• Ambiguity of OEM’s approaches for electrification can be studied
in advance
• Customer module provides robust method for integration into any
engine models
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