downsizing powertrains

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Downsizing PowertrainsNVH Implications and Solutionsfor Vehicle Integration

Unrestricted © Siemens AG 2017

Siemens PLM Software

Downsizing PowertrainsNVH Implications and Solutions for Vehicle Integration

Downsizing trends and NVH impact

Traditional Approach for NVH studies

New Integrated approach

Examples:

Low Frequency Booming Noise

Clunk



Addressing the challenges

Continued focus on fuel economy & emissions NVH & driving pleasure impacted by fuel economy

Multitude of options to be evaluated New materials new engineering challenges



Technical impact of the fuel economy race

Introduction of new technologies for transmissionsStop & start, Hybridization, Robotized Automated Manual Transmissions (AMT), DualClutch Transmissions (DCT), Continuous Variable Transmission (CVT), Increase ofgear ratios up to 10 in AT, CPVA (Centrifugal Pendulum Vibration Absorber)Dampers technologies on pendulum, DMF, Variable stroke pumps, ...Control strategies to reduce LU opening, CVT clamping pressure, increase energy

Growing stresses in the drivelineWeight reduction, reduced size of componentsDownsizing/down-speeding engines increases acyclism

Attributes balancing requirementDefining the best compromise between fuel economy, performance, drivability andvibration/acoustics is requested to improve brand value



Reducing CO2 at the price of NVH and driving comfort?

Driv

ers

forn

ewve

hicl

ede

velo

pmen

tEm

issi

on&

Fuel

Econ

omy

Ligh

tW

eigh

tN

ewP/

T&

Driv

elin

eC

once

pts

Downsized ICE / Hybrid modeHigher torque irregularitiesDriveline integration issues

EV-mode operationNo LF ICE maskingLF and HF issues

Multi-Attribute BalancingBody Weight vs Body Stiffness

Increased RoadNoise

P/T BoomingClunk, rattle

Non-speed related

Electric MotorNoise

Static StiffnessHandling

Ride comfortNVH

HVAC & AuxiliaryNoise

Tip-In/OutKey-On/Off

Mode switch



Integrated Design and Verification: Full Vehicle NVHFront Load and Virtualize DecisionsModel Complete Systems Predict and Verify

Target Setting &Concept Finalization

Concurrent & IntegratedDesign and Verification

Improved Systems Integration& Virtualize Testing

Optimize Test and Validation, withCorrelation to the Virtual

Control Algorithms & Embedded Software

Verify sub-system

behaviorPhysical TestSystem

Verification

Detailed Design Virtual VerificationPre-Program Physical Verification

BenchmarkingTarget Setting

Load Identification

PWT, Chassis & PlatformConcept

TEST

CAE

Release for mule SOPRelease for preproduction

Release forprototype



Analysis requirements for vehicle integration performance

Requirements vs.Frequency

0.1 1 10 100 1000 10,000

Vehicle Level

Human Input

Powertrain / Throttle

Road / Suspension

Excitation modelFidelity

Driveability

Ride & Handling

NVH

HandlingPrimary Ride

Secondary Ride

Steering input

blockshighway

wheel unbalance

fore aft shuffle 2nd order gear rattle & whineidle

Map-based responseLumped parameters

Dynamic torque calculationIncreasing component parameterization

Unrestricted © Siemens AG 2017 Siemens PLM Software

CO2 reduction effect on NVH

Engine Speed

VibrationLock-up open

3. Expand L-UP condition2. Lower number of cylinder1. Increase engine power

Present

NVH cause & effects fromCO2 reduction

CO2Reduction

IncreaseInterior Noise

& vibration

(4) IncreasedCombustion

Related Noise

(2,3) IncreaseDrivelineEfficiency

Reducedisolation

Compromisedstiffness/NVH

pack

(1) ImproveEngine

Efficiency

Reducevehicle weight

Past







Examples:


Clunk



Traditional technologies for NVH studies

Method Insight Limitation Picture

TransferPathAnalysis

Separate rootcause of vibration/ noise

Time consuming,single configuration

OperationalDeflectionShapes

Visualization offorced response,ability to selectkey components

Vehicle level only,no rotationaldynamics

Full 3D Detailedoptimizationpossible

Exploration ofrotational dynamicsnot easy

1D Driveline Detailed rotationaldynamics

Full vehicledynamics not easyto include



Modifysuspension mode

Traditional driveline NVH evaluation approachLimitation

Classical approach AssumptionsModification prediction Limitation in low frequency booming range

EngineGbx

Body

Shaft

Change shaftstiffness

Modifyrotational mode

Modifiedinput

Changesuspension

stiffness

Coupling withrotational

mode

Non-linear mountstiffness

Influence ofthe preload

Clutch stiffnessespecially with DMF

Influence ofthe preload







Examples:


Clunk



New integrated approach

My model is correct,

My measurement is correct,your

engineers combining 1D simulation, 3Dsimulation and testing capabilities

technologies to provide the



Context / Expectations from customer - Booming

General trend: increasing pressure on fuel economyDownsized enginesAdvanced torque lock-up strategies (for the case of automatictransmissions)Cylinder deactivation

ConsequencesUse of the engine at lower RPMsHigher torque irregularities due to lower cylinder numberHigher booming noise and vibration

QuestionsHow are competitors dealing with booming noise?

What is the efficiency of the driveline rotational damper?How are torsional vibration transferred to the cabin?What is the root cause of the high torsional vibration?Is there any coupling of structural modes to rotational dynamics?What is the real added value of a CPVA or a DMF?



LMS Engineering answer - Booming

Full vehiclemodel

diagnosis

Performance ofdrivelinedamper

Full vehicletest

diagnosis

Evaluate the performance of the damper

Identify the problem and pinpoint the maincontributors

Objectivize the decision making process for nextdriveline designProvide information about components notavailable from supplier



EngineTorque

converter Transmission

Torqueflow

Characterization of lock-up damperLock up and damping performance analysis

Lock Up point

Engine Gearbox

Damping map

Lock up mapWhat is the effective range ofthe lock-up damper?

How efficient is the lock-updamper?



Full vehicle diagnosis using test based loadidentification in time and frequency domain, ODS, EMA

Trimmedbody FRF

Full vehicleFRF

Operationalmeasurements

Transfer pathanalysis

Test based diagnosis



Full vehicle model creationFull component visibility

Component testing

Reverse engineeringObtaining model parameters not available to the customer

Torsional damperstatic and dynamic

characterization

Powertrain mountsstiffness

Driveshaftcharacterization

Suspension/bodycharacterization

Benchmark vehicleNo parameters



Calculation of acoustic target response based oncombustion pressure excitation

Combustion pressuremaps as model input

Interface forcescalculated from full

vehicle model

Target responsecalculated based on

model loads +measured FRF

Model loads

Test FRF

Target response



Context / Expectations from customer Multi-attribute balancing

General trend: higher competitor pressure on vehicle marketDifferent attributes in different departments: design decisions can impactother teams, cross department communication not always easyNeed to save vehicle development cost

ConsequencesFront loading multi-attribute study to early development phaseBalance between fuel economy, performance and vehicle comfort requiredNeed accurate models that can handle different attributes

QuestionHow to balance the comfort/fuel economy request?

How to frontload multi-attribute balancing?How to properly define a unified modelling environment?How to provide objective evidence that performance is notcompromised?Where should we direct our investment strategy for Fuel Economy/NVH?

Fueleconomy

Comfort/PerformComfort/

Performance



LMS Engineering answer Multi-attribute balancing

Multi-attributeoptimization

loop

Full vehicleunified testing

campaign

Multi levelmodelingstrategy

Evaluate the vehicle performance for eachattribute

Get the right detail level for the attribute to bestudiedBalance the model complexity with the end userneed

Understand the coupling effect between theattributesDefine the best design strategy for attribute co-optimization



Multi-attribute evaluation (unified testing)

Multi-physicmeasurement

Heavyinstrumentation(>200 channels)

Metric evaluationfor multiple

characteristics

Target setting

Data processing formodel input and

validation

Vehiclediagnosis

Multi-attributeevaluation

cross couplingbetween the

attributes



Balance between accuracy and complexity

Accuracy of the modelCalculation time



Automatic optimization processes to gain insight in design

Selection ofsensitive

parameters fromDesign Of

Experiment

Multi objectiveoptimization

Best solution formulti attribute

balancing

Customization

GUI fit for everyuser level

Expert

CAE engineers

Vehicle engineers







Examples:


Clunk



Aisin AWRelying on LMS Engineering to strengthen its position as technology partner

Reducing booming, judder and gear noise

Gained 50 percent time reductionwhen troubleshooting a new NVHissueSignificantly reduced overalldevelopment timeRecognized as technology partnerof automotive OEMs, resulting incompetitive advantage

NVH techniques we learned from LMS Engineering services are now part ofour standard development process, such as transfer path analysis

Hiroki Tsuji, Group Manager, Core Component Engineering Department

Deploy a full vehicle model based approach for the prediction and elimination of clutch judderEmploy full vehicle modeling approach combining test, 3D and 1D simulation methodologies

Full-vehicle simulationEnergy flow lock-up booming

L-up ON



5) Simulation, correlation andmodel based diagnosis

Aisin AWProcess lock-up booming investigation

1) Testing

2) Test based diagnosisIn-depth test investigation including transferpath analysis (TPA) and operationaldeflection shapes (ODS)

3) 1D Driveline modeling1D model consists of engine model andtransmission model

4) 3D Vehicle modeling

ODS mode

LMS Imagine.Lab

LMS Virtual.Lab

Coupledsimulation

Forcedresponse

Linear analysis

Engine Speed

Optimize target vibration

Internal transmission rpm

Measurement of input & validation data,data for load identification

Powertrain block &mountsSubframeChassisFront & rearsuspensionDriveshafts & tires

TPA contribution



Automobili LamborghiniCreating a new driveline concept design using LMS Imagine.Lab Amesim

Designing the Aventador LP700-4 torsional vibro-acoustic driveline

Designed the torsional vibrationcharacteristic of the AventadorLP700-4 drivelineSupported torsional vibro-acousticdriveline optimization

true power of LMS Amesim is demonstrated by how easy it is to evaluatedifferent driving conditions, software or hardware changes and even different

Ing. Claudio Manzali, R&D

Model easily complex dynamic systems using prepackaged componentsGenerate models in function of the phenomena the user intends to investigate

Torsional behavior of the drivelinePowertrain and gearbox noise optimization



Simcenter solutions for Automotive NVH & Acoustics

Legislation and regulation

New powertrain concepts

Lightweight structures

Increase vehicle performance

downsizing powertrains

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