nvh challenges and solutions for modern and electrified ...challenges+and... · stephan brandl avl...

Stephan BRANDL

AVL List GmbH (Headquarters)

Public

NVH CHALLENGES AND

SOLUTIONS FOR MODERN AND

ELECTRIFIED POWERTRAINS

AVL Vehicle and Powertrain NVH

Stephan BRANDL, Wolfgang SCHWARZ, Andreas LOECKER | Vehicle and Powertrain NVH | 24 November 2016 | 2Public

NVH for Conventional Powertrains

Powertrain Development using Simulation and Measurement

Engine Roughness

Combustion Noise (Diesel Knocking)

Turbocharger NVH

Driveline NVH

NVH in Electrification

AVL’s E-Driveline Development Approach

NVH Frontloading for Power Electronics

CONTENT

DEVELOPMENT APPROACHES FOR MODERN POWERTRAINS




Engine Roughness


Turbocharger NVH

Driveline NVH




CONTENT



Comprehensive Simulation Model Fully elastic; oil film bearings

COMBUSTION NOISE- ROUGHNESS


EHD

bearings

All parts

flexible

Measured

Cylinder Pressure

Engine Mount

Dynamic StiffnessEngine Mount

Dynamic Stiffness

Engine Mount

Dynamic Stiffness

TVD Dynamic

Stiffness & DampingEHD

bearings


Powertrain NVH Assessment

Installation on powertrain test bed

Application of sensors

Close to main bearing (excitation correlation)

Engine surface (flexible part correlation)

Data acquisition

Data evaluation and comparison to simulation

POWERTRAIN DEVELOPMENT - USING SIMULATION AND MEASUREMENT



Simulation Model Verification

Sensor Position x, y, z




Root Cause Analysis

Modal Contribution Analysis

Transfer Path Analysis

NVH Source Identification



Cam cover




Engine Roughness


Turbocharger NVH

Driveline NVH




CONTENT



Why Do We Need Objective Sound Quality Criteria?

Example: Overall Level vs. Sound Quality Criterion

INTRODUCTION

DIESEL COMBUSTION NOISE



Theory

Benefits

Calculation based on cylinder pressure (possible in non-acoustic environments)

Drawbacks

Influence of engine structure not considered

High effort to install cylinder pressure sensors

CNI (COMBUSTION NOISE INDEX)

Cylin

de

r P

re

ssu

re

-

ba

r

AVL CNI

Filter

Pressure Trace AVL CNI vs. °CA

CN

I

(Peak –

Peak)

AVL CNI vs. TorqueC

ylin

de

r P

re

ssu

re

-

ba

r

Cylin

de

r P

re

ssu

re

-

ba

r

Time

Masking

Consideration


Theory

Benefits

Only microphone measurement

Influence of engine structure considered

High agreement between subjective assessment and CKI value

Drawbacks

Calculation based on airborne noise (for benchmarking)

CKI (COMBUSTION KNOCKING INDEX)


Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plit

ud

e

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plit

ud

e

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plit

ud

e

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plit

ud

e

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Transfer Function

0.00 0.05 0.10 0.15 0.20 0.25Time - s

-0.4

-0.2

-0.0

0.2

0.4

Am

plitu

de

3000 UPM

2000 UPM

1000 UPM

Leerlauf

Band Pass and

Envelope Calculation CKI Result

Consideration of

Time and Frequency Masking


DIESEL COMBUSTION NOISE ASSESSMENT


Combustion Noise Assessment

Cylinder PressureGlow Plug Adapter

Structure BorneAccelerometer

AirborneMicrophone

AVL Algorithms for Combustion Knocking

AVL CNICombustion Noise Index

AVL CKI SBNCombustion Knocking Index

AVL CKI ABNCombustion Knocking Index

Combustion Noise Benchmarking(engine test bed, vehicle interior)

Combustion Noise Development

Combustion Noise Monitoring


NEW MEASUREMENT PLATFORM

• expandable to 96 channels• flexible configuration• exchangeable modules


A COMPLETE SET OF DIESEL NVH ALGORITHMS

AVL offers a complete set of algorithms for Diesel combustion noise assessment. These algorithms are suitable to cover the complete development process to ensure that NVH development targets will be successfully reached.

AVL CKICombustion Knocking Index

AVL CNLCombustion Noise Level

AVL CNICombustion Noise Index


Object: Ford Panther

GraphicDef.: AVL ENG ABN - A265008

Page: ABN max Torque

0 % Load 1750 rpm

50 % Load 1750 rpm

100 % Load 1750 rpm

31.5 100 315 1k 3.15k 10k

Octave Frequency - Hz

20

30

40

50

60

70

80

90

100

Sound P

ressure

- d

B(A

)

MP1: Top

73.1 dBA

83.0 dBA

83.4 dBA

31.5 100 315 1k 3.15k 10k


20

30

40

50

60

70

80

90

100

Sound P

ressure

- d

B(A

)

MP2: Right

76.8 dBA

86.7 dBA

85.9 dBA

31.5 100 315 1k 3.15k 10k


20

30

40

50

60

70

80

90

100

Sound P

ressure

- d

B(A

)

MP3: Front

75.9 dBA

86.5 dBA

85.7 dBA

31.5 100 315 1k 3.15k 10k


20

30

40

50

60

70

80

90

100

Sound P

ressure

- d

B(A

)

MP4: Left

76.7 dBA

86.8 dBA

85.6 dBA

31.5 100 315 1k 3.15k 10k


20

30

40

50

60

70

80

90

100

Sound P

ressure

- d

B(A

)

AVG All Mics

75.9 dBA

86.0 dBA

85.2 dBA

3rd OCTAVE SPECTRA2000 rpm with different loads



Page: ABN nru l100 OL+Oct

Test: 100 % Load Run Up

Overall Level

Octave 500 Hz

Octave 1000 Hz

Octave 2000 Hz

Octave 4000 Hz

1000 2000 3000 4000

Rotational Speed - rpm

60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

MP1: Top

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

MP2: Right

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

MP3: Front

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

MP4: Left

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

AVG All Mics

OVERALL & OCTAVE LEVELS100% load run up



Page: ABN nru l100 3d

Test: 100 % Load Run Up

0 200 400 600 800 1000

Frequency - Hz

1000

2000

3000

4000

Rota

tional S

peed

- rp

m

10

20

30

40

50

60

70

80

90

Sound P

ressure

- d

B(A

)

2 4 6 8 10MP1: Top

0 200 400 600 800 1000

Frequency - Hz

1000

2000

3000

4000

Rota

tional S

peed

- rp

m

10

20

30

40

50

60

70

80

90

Sound P

ressure

- d

B(A

)

2 4 6 8 10MP2: Right

0 200 400 600 800 1000

Frequency - Hz

1000

2000

3000

4000

Rota

tional S

peed

- rp

m

10

20

30

40

50

60

70

80

90

Sound P

ressure

- d

B(A

)

2 4 6 8 10MP3: Front

0 200 400 600 800 1000

Frequency - Hz

1000

2000

3000

4000

Rota

tional S

peed

- rp

m

10

20

30

40

50

60

70

80

90

Sound P

ressure

- d

B(A

)

2 4 6 8 10MP4: Left

0 200 400 600 800 1000

Frequency - Hz

1000

2000

3000

4000

Rota

tional S

peed

- rp

m

10

20

30

40

50

60

70

80

90

Sound P

ressure

- d

B(A

)

2 4 6 8 10AVG All Mics

3D SPECTRA 0-1 kHz100% load run up


GraphicDef.: AVL ENG CN Diesel - A265008

Page: CNI_nru_lvergl

AVL Scatterband

AVL Target Line

Cylinder Pressure 1

Cylinder Pressure 2

Cylinder Pressure 3

Cylinder Pressure 4

1000 2000 3000 4000 5000


0

50

100

150

200

AV

L C

NI -

kP

a

100 % Load Run Up

1000 2000 3000 4000 5000


0

50

100

150

200

AV

L C

NI -

kP

a

160Nm Run Up

1000 2000 3000 4000 5000


0

50

100

150

200

AV

L C

NI -

kP

a

80Nm Run Up

1000 2000 3000 4000 5000


0

50

100

150

200

AV

L C

NI -

kP

a

40Nm Run Up

1000 2000 3000 4000 5000


0

50

100

150

200

AV

L C

NI -

kP

a

20Nm Run Up

1000 2000 3000 4000 5000


0

50

100

150

200

AV

L C

NI -

kP

a

0 % Load Run Up

AVL CNILoad run ups


GraphicDef.: AVL ENG CN Diesel - A265008

Page: CKI_nru_lvergl

AVL Scatterband

AVL Target Line

MP1: Top

MP2: Right

MP3: Front

MP4: Left

1000 2000 3000 4000 5000


100

120

140

160

180

200

220

240

260

AV

L C

KI

100 % Load Run Up

1000 2000 3000 4000 5000


100

120

140

160

180

200

220

240

260

AV

L C

KI

160 Nm Run Up

1000 2000 3000 4000 5000


100

120

140

160

180

200

220

240

260

AV

L C

KI

80 Nm Run Up

1000 2000 3000 4000 5000


100

120

140

160

180

200

220

240

260

AV

L C

KI

40 Nm Run Up

1000 2000 3000 4000 5000


100

120

140

160

180

200

220

240

260

AV

L C

KI

20 Nm Run Up

1000 2000 3000 4000 5000


100

120

140

160

180

200

220

240

260

AV

L C

KI

0 % Load Run Up

AVL CKILoad run ups



Page: ABN nru Condition

100 % Load Run Up

160Nm Run Up

80Nm Run Up

40Nm Run Up

0 % Load Run Up

Motored Run Up

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

MP1: Top

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

MP2: Right

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

MP3: Front

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

MP4: Left

1000 2000 3000 4000


60

70

80

90

100

110

Sound P

ressure

- d

B(A

)

AVG All Mics

Various possibilities are given to display microphone, accelerometer, cylinder pressure signals as well as results of customized analysis algorithms. Both time and crank angle based data can be processed

CYLINDER PRESSURE

INJECTION SIGNALS

INDICOM & NVH SIGNAL PROCESSING TOOLS


SIMULATION BASED KNOCKING EVALUATION


Transfer

Source /

Excitation

Mechanism

Response

CRUISE M crank angle resolved and mixture controlled combustion (MCC) simulation

excitation source and mechanisms

Pressure in combustion chamber

CNI

structural response

Internal force path (transfer function)

Accelerometer position

CKI SBN

Microphone position

radiated air

borne noise

External force path / radiation (transfer function)

CKI ABN




Engine Roughness


Turbocharger NVH

Driveline NVH




CONTENT



TURBO CHARGER NOISE PHENOMENA

TURBOCHARGER NOISE QUALITY PARAMETERS FOR TC NOISE ASSESSMENT AND REFINEMENT

Tonal Noises => directly related to the TC

Constant Tone Unbalance Whistle Noise Blade Passing Noise Ball Bearing Noise

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000 20000

Frequency - Hz

1500

2000

2500

3000

3500

4000

4500

Ro

tatio

na

l S

pe

ed -

rp

m

10

20

30

40

50

60

70

80

90

So

un

d P

ressu

re -

dB

A

Turbo charger nearfield

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Frequency - Hz

3

4

5

6

7

8

9

Tim

e -

s

30

40

50

60

70

80

90

100

110

So

un

d P

ressure

- d

BA

Intake orifice lhs

Broadband Noises => non-synchronous, related to TC / intake system

Flow Noise Let Off Noise

0 5000 10000 15000 20000

Frequency - Hz

1500

2000

2500

3000

3500

4000

Ro

tatio

na

l S

pe

ed -

rp

m

20

30

40

50

60

70

80

90

100

So

un

d P

ressure

- d

BA

Intake orifice

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Frequency - Hz

1000

1500

2000

2500

3000

3500

4000

Ro

tatio

na

l S

pe

ed -

rp

m

20

30

40

50

60

70

80

90

100

So

un

d P

ressure

- d

BA

Intake orifice 1500 2000 2500 3000 3500 4000

Frequency - Hz

1500

2000

2500

3000

3500

4000

4500

Rota

tional S

peed

- rpm

10

20

30

40

50

60

70

80

90

Driver's ear lhs - Sound Pressure - dB(A)

1500 2000 2500 3000 3500 4000

Frequency - Hz

1500

2000

2500

3000

3500

4000

4500

Rota

tional S

peed

- rp

m

10

20

30

40

50

60

70

80

90

Driver's ear rhs - Sound Pressure - dB(A)

1500 2000 2500 3000 3500 4000

Frequency - Hz

1500

2000

2500

3000

3500

4000

4500

Rota

tional S

peed

- rpm

10

20

30

40

50

60

70

80

90

Firewall top lhs - Sound Pressure - dB(A)

1500 2000 2500 3000 3500 4000

Frequency - Hz

1500

2000

2500

3000

3500

4000

4500

Rota

tional S

peed

- rp

m

10

20

30

40

50

60

70

80

90

Firewall top rhs - Sound Pressure - dB(A)

0 5000 10000 15000 20000

Frequency - Hz

0

1

2

3

4

5

6

Tim

e -

s

20

30

40

50

60

70

80

90

100

So

un

d P

ressure

- d

BA

Intake orifice lhs


MEASUREMENT OF INPUT DATA / DETECTION


Measurement Setup Operating Conditions

Artificial Head

Intake Orifice

Near-field

Accelerometer

TC Near-field

Cylinder Block

Air filter

housingIn

terc

oo

ler

Vehicle Interior

Engine

Compartment


TONAL NOISE CALCULATION EXAMPLE


Blade Passing Noise Improvement during Development Process

0 2000 4000 6000 8000 10000 12000

Frequency - Hz

8

9

10

1 1

12

13

14

15

16

Tim

e -

s

-10

0

10

20

30

40

50

60

70

Co-Driver ear lhs - Sound Pressure - dB(A)

0 2000 4000 6000 8000 10000 12000

Frequency - Hz

5

6

7

8

9

10

1 1

12

13

Tim

e -

s

-10

0

10

20

30

40

50

60

70

Co-Driver ear lhs - Sound Pressure - dB(A)Interior Noise

Baseline with HFD

The vehicle showed a high blade passing order in baseline condition. Implementing a high frequency damper on

pressure side of the turbocharger significantly improved the noise.

Blade Passing Noise Parameter 6.0 => 8.2


Overview of Current Capabilities

Development Measures

Critical Speeds

Rotor Displacements

Speeds of Floating Bushings

Bearing Forces, Oil Film Pressures

Oil Flows, Oil Temperatures

Dynamic Simulation

Integrated

TURBOCHARGER NOISE- SIMULATION


Rotor

Floating Bushings

Housing


20000 rpm


Harmonics

Oil Pressure Distribution

Rotor Orbital Path; Detecting Unstable Conditions

TURBOCHARGER NOISE- SIMULATION


First order frequency

from unbalance

Sub harmonics (can

only be predicted when

using EHD bearing

definition) can be

identified (important for

NVH)

Typical

displacement at the

compressor nut

Unstable behavior

at 140000 rpm150 cycles

last 50 cycles of total 150

cycles are plottedFrequency




Engine Roughness


Turbocharger NVH

Driveline NVH




CONTENT




Fully Flexible Driveline

NVH DRIVELINE DEVELOPMENT- SIMULATION


Engine mount

characteristics

Sound radiation

Excite model incl.

bending and torsion


STEPWISE DEVELOPMENT APPROACH


Entire Drive Line

Bending &Torsional Model

Engine Alone Engine & Transmission Entire Drive Line

Torsional Approach

Flexible Rear Sub-frame Flexible Sub-frame

and Power Unit


Main measurement parameters

Torsional vibration

Acceleration

Sound Pressure Level

ECU data

NVH DRIVELINE DEVELOPMENT- MEASUREMENT


In Vehicle Assessment

Dyno Assessment


Virtual testing

Use simulation for component/subsystem optimization

Connect existing simulation models to perform virtual system testing

Real Testing

Replace hardware components by dynos for subsystem or component testing

E.g. Clonk testing on PT test bed

Mixed testing

Replace hardware components by simulation models

Replace simulation models by hardware components

NVH DRIVELINE DEVELOPMENT- MEASUREMENT





Engine Roughness


Turbocharger NVH

Driveline NVH




CONTENT



FULL ELECTRIC VEHICLES (EV)CONCEPTUAL APPROACHES

Differential

Single step

final drive

Differential

Planetary gear

set for speed

reduction

BMW i3 Axle Drive

ZF Electric Drive

RENAULT Zoe

Single step

final drive

Differential

GM‘s Electric Drive

Differential

Planetary gear

set for speed

reduction

Tesla Model S RWD and AWD

Single step

final drive

DifferentialSingle step

final drive

Differential

Co-axial layout

with hollow shafts

Parallel-axial

layout


ELECTRICAL AND MECHANICAL NOISE OF FULL ELECTRIC DRIVELINE

Shaft bearings

Gears

Shafts

Torque ripple to driveline

Electrical excitation, electromagnetic field

Mechanical excitation, Multibody dynamic

Sound radiation, from two sources, electrical excitation and driveline

Driveline mount

Structure borne noise to the vehicle structure



FEM magnetic fieldRadial, tangential &

bearing forces mapped

to FEM

Ripple torque Multi-body Dynamic

Driveline, whine, etc.

Export excitation in

frequency domain

Coupled simulation excitations

in frequency domain (forced

response analysis)

Torque and bearing forces to EXCITE,

calculate eccentricity and come back

Tool:

Ele

ctr

ical N

ois

e

Mech

an

ical N

ois

e

PWM Harmonics

0

-20

-40

-60

20

40

60

Isa Isb Isc

0.3 0.32 0.34 0.36 0.38 0.4

Time (s)

0

20

40

60

80

100

Tem_IM4

Electrical + Mechanical


Electromagnetic excitation Electromagnetic excitation

+ Mechanical





Engine Roughness


Turbocharger NVH

Driveline NVH




CONTENT



E-COMPONENT AUDIBLE NOISE PREDICTION POWER ELECTRONIC

Target:

Noise distribution prediction of emitted noise from the source (single components L, C, silicon) via the distributor (PCB (printed circuit board), mechanic, housing) to vehicle interior without hardware.

Benefit:

Simulation driven assessment and optimization already in an early phase of development

Support component selection and schematic diagram development

Improved positioning strategies and structural design of PCB and housing

Assessment of noise contribution to vehicle interior estimation of annoyance


E-COMPONENT AUDIBLE NOISE PREDICTION POWER ELECTRONIC

Approach:

Noise source prediction by simulation in an early phase, based on

schematic diagrams

technical component information

Noise transfer prediction via simulation of

structural vibrations and

radiated noise

Physical model

Noise source analysis at start of development Noise transfer during development

Schematic based audible noise detection CAE based audible noise simulation

I/U/f


VALIDATION OF PCB STRUCTURAL MODEL

Mass 27.695 g

Free-Free Conditions

Detailed 3D FEM Model (NASTRAN)

RBE2’s

CBAR’s

SPC’s

Constrained (mounted on bed plate):

Tin (SnPb)

Copper (Cu)

Non-isotropic material FR-4

Results of FEM modal analysis and forced response

analysis are compared in terms of eigenfrequencies and transfer functions measured with laser vibrometer.

• PCB without excitation Eigenfrequencies

• PCB with excitation (x, y) position dependence


MODELING OF TEST BOARD – EXCITATION POSITIONS

EXPERIMENTAL SYSTEM IDENTIFICATION OF ELECTROACOUSTIC TEST BOARD

20mm

25

mm

columns

rows

f00

f22

f44

Animation of Excitation Positions

Excitation by

small hammer


377 Hz 567 Hz 906 Hz 924 Hz 1144 Hz

1582 Hz 1822 Hz 1855 Hz 2541 Hz 2734 Hz

2801 Hz 3076 Hz

FREE-FREE EIGENFREQUENCY ANALYSIS

Measurement


TRANSFER FUNCTION COMPARISONFULLY ISOLATED PCB

f11 f22 f33

Fully isolated by elastic bands

• System Response of fully Isolated

System – V1.0 – (laser vibrometer)

• FEM free-free calculation sol111

F-range: 0-5kHz (coherence (evaluation window): 270Hz – 3kHz)


TRANSFER FUNCTION COMPARISONPCB MOUNTED ON BED PLATE

f11 f22 f33

• System Response with mounted plate

(“Bed Plate”) – V1.1 (laser vibrometer)

• FEM constrained calculation sol111

Frequency range: 0 - 5kHz (coherence: 270Hz – 3kHz)

Mounted on “Bed Plate”



Complete powertrain models can be used in early development phase to predict complex NVH phenomena (e.g. roughness)

Improved NVH simulation and parameters for components (e.g. Turbocharger NVH)

Simulation delivers valuable imput in NVH driveline development


Electromagnetic and mechanical (esp. gear contact) excitation need to be considered

New NVH frontloading approaches for Power Electronics are under investigation

SUMMARY


www.avl.com

THANK YOU

nvh challenges and solutions for modern and electrified ...challenges+and... · stephan brandl avl...

Documents