nvh development process for edrive systems€¦ · 15-05-2018 · nvh development process for...
TRANSCRIPT
NVH Development
Process for eDrive
Systems
Dr. Oliver Grieshofer,
Manager, Dynamics / Acoustics,
Magna Powertrain
NVH DEVELOPMENT PROCESS FOR eDRIVE SYSTEMS
• Acoustic challenges for eDrivedevelopment to fulfill OEM and driver’s expectation
• NVH has to be considered from the early development phase
• All major influences have to be included
NVH development process from concept design to vehicle integration was established
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eDRIVE NVH PROCESS OVERVIEW
NVH
Simula-tion
System
Test
Vehicle
Test
Design
EM
Simula-tion
Gear
Analysis
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eDRIVE NVH PROCESS OVERVIEW
4
NVH
Simula-tion
System
Test
Vehicle
Test
Design
EM
Simula-tion
Gear
Analysis
CHALLENGES FOR eDRIVE NVH SIMULATION
• Excitation mechanisms from magnetic forces and gear
interaction to be considered
• High excitation orders and rotational speed lead to high
excitation frequencies
• ICE 4-cyl: 2nd order * 6,000 rpm = 200 Hz
• eDrive: 82nd order * 15,000 rpm = 20,500 Hz
• Modal reduction of model up to high frequency
large number of modes
• eMotor, gearbox and inverter are a coupled structure
NVH evaluation of system
• NVH assessment of structure and air-borne path
complete surface to be evaluated
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SIMULATION PROCESS
FE-model
Gear analysis
EMAG analysis
•MNOISE gear run-up
simulation of meshing
forces
•Transform forces to
frequency domain for
rpm steps
•Define evaluation
surfaces
•Collect all simulation
results: gear and
EMAG
•Post processing
•Surface noise
•Structure points
FE modal
response
analysis
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GEAR DESIGN FOR NVH
Macro GeometryExcitation orders
Contact ratios
Micro GeometryTransmission errorMeshing stiffness
Stiffnessmatrix from
FEA
Loads
EM
excitation
orders
Package
... andmanymore
MNOISE GEAR
• MNOISE gear analysis
• Input from gear design
• general gear data
• non-linear meshing stiffness curve in operation point
• Time domain run-up simulation with multi-body model
• Evaluation of meshing forces
Tin
nout
Angle
Stiffness
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FE-MODEL OF eDRIVE
Complex FE-model of eDrive
• Inner parts like shafts, bearings and wheels included
• Inverter housing without detailed electronics
• Test rig boundaries necessary for validation, e.g. mounts, side shafts
• Modal reduction: 1,000 < modes
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MNOISE NVH RESULTS
• MNOISE post-processing
• Collect all simulation results
• Campbell of run-up: surface or single point results
• Evaluation method examples
Order cutevaluate noise level and vibration of main orders
Speed cutat defined rpm identify main contributing frequencies
Frequency intervalinvestigation of resonance phenomena
Speed cut
Order cut
Frequency integral
Speed
Fre
qu
en
cy
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MNOISE NVH RESULTS
MNOISE post-processing
• Order cutmain contributing panels can be identified
• Frequency intervalfind surface area with highest noise level
• Animate operational deflection shape to find reinforcement potential
output shaft rpm300 900 1500
No
ise
leve
l
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Frequency
Nois
e leve
l
5dB
NVH IMPROVEMENT EXAMPLE
NVH improvement example
• MNOISE analysis of base design showed noise peak
• Gear box cover had main contribution
• Structural weakness identified –reinforcement ribs added
• Peak was eliminated in MNOISE analysis of new design
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SYSTEM TESTS
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NVH
Simula-tion
System
Test
Vehicle
Test
Design
EM
Simula-tion
Gear
Analysis
eDRIVE NVH TEST RIG
Test rig requirements
• Modular design for different eDrive concepts
• Dynamic stiff structure to minimize influence
• Easy access and handling
• For validation of simulation, rig model included in NVH analysis
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TEST BENCH SETUP
• Flexible semi-anechoic test cell
• Full acoustic housing of secondary brake
• Acoustic camera to find
hot spots
• Microphones at inverter
nearfield and standard
1m positions
• Accelerometers
active/passive side
mount positions to
check isolation
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Acoustic camera
SIMULATION RESULT VERIFICATION
NVH characteristic is predicted correctly
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Surface sound pressure (dBA) 1m sound pressure (dBA)
Intermediate shaft speed (1/min)
1000 2000 3000 4000 1000 2000 3000 4000
1000
2000
3000
4000
5000
Fre
quency
(Hz)
VEHICLE TESTS
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NVH
Simula-tion
System
Test
Vehicle
Test
Design
EM
Simula-tion
Gear
Analysis
NVH DEVELOPMENT PROCESS FOR eDRIVE SYSTEMS
Summary and conclusion
• NVH development process for eDrives established
• Applicable for 48V and high voltage systems
• Acoustic improvement before prototype
• Verified acoustic simulation results
• Reach component target in cooperation with OEM
• Fulfill end customer expectation for successful cars
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