Excellence in Automotive R&Dturbo-moteurs.cnam.fr/publications/pdf/conference1_2011.pdf · Excellence in Automotive R&D Hybrid Electric Vehicles Development Processes & Challenges

Excellence in Automotive R&D

Hybrid Electric Vehicles

Development Processes & Challenges

Dr. Olivier Imberdis, IAV France

12th SIA – CNAM Conferences Serie, March 8th 2011

© IAV GmbH · 03/2011 · IAV-France · IAV_SIA_Presentation.ppt 2

Content

• Driving forces for alternative drive trains

• Classification & Potentials of HEV

• Impact on development processes

• Outlook

• Simulation as a continuous development tool


Content




• Outlook



Availability of Oilworld wide oil production 1900 - 2050

Quelle: BGR 2004

accumulatedoil

convent. Oil

Projection

non conventionaloil resources (oilshale, fat oil...)

1900 1925 1950 1975 2000 2025 2050 2075 2100 2125 2150

0

1

2

3

4

Gt


Estimated Vehicles Countvehicles on the road world wide until 2050

� Africa

� Latin America

� Middle East

� India

� other asian states

� China

� East Europe

� GUS

� OECD Pacifik

� OECD Europa

� OECD Nord Amerika

source: VDA/WBCSD

0

0,5

1

1,5

2

Mill

iard

en

2000 2010 2020 2030 2040 2050


CO2 Emission Goals – Manufacturers penalties

between 5 and 25 €from 1 to 3 g/km

95 € per excess grammover 3g/km

Manufacturer penalties

CO2 emissions with NEDC

80

100

120

140

160

180

200

19

95

19

96

19

97

19

98

19

99

20

00

20

01

20

02

20

03

20

04

20

05

20

06

20

07

20

08

20

09

20

10

20

11

20

12

20

13

20

14

20

15

20

16

20

17

20

18

20

19

20

20

CO

2 e

mis

sio

ns

[g

/km

]

0

20

40

60

80

100

120

1995 2000 2005 2010 2015 2020

ve

hic

le r

es

pe

cti

ng

CO

2 e

mis

sio

ns

[%

]

CO2 ACEA target [g/km] Gasoline [g/km] Diesel [g/km]

source: ACEA


Content




• Outlook



Classification & PotentialsHybrid Systems Introduction

Classification

Potentials of HEV

... According to Topology

... Gasoline and Diesel

... Fuel Efficiency

... According to Powertrain Functionality



Classification

Potentials of HEV



... Fuel Efficiency



Parallel Hybrid

� pure mechanical power transfer

� modification of operating point dependent on electric

power

� numerous technical designs (Mild / Full Hybrid) possible

Power Split Hybrid

� power transfer both mechanical and electrical

� strong modification of operating point possible

� biggest fleet based on hybrid electric vehicles from

Toyota

Series Hybrid

� pure electrical power transfer

� complete modification of engine operating point possible

� application in electric vehicles as range extender

Classification based on TopologyHybrid Systems Introduction


Parallel HybridHybrid Systems Introduction

� pure mechanical power transfer

� 1 electric machine is sufficient

� transmission needed

� several technical configurations

• Mild / Full hybrid

• torque addition

• single- / double-shaft

Advantages:

+ scaleable system regarding the electrical power

+ good efficiency chain

Disadvantages:

- regenerative braking depending on the technical configuration

- limited modification of ICE operating point

- limited power assist and regenerative braking by low power of the electric motor

Examples:

• Honda Civic Hybrid

• VW Touareg Hybrid


Power Split HybridHybrid Systems Introduction

power transfer both mechanical

and electrical

� minimum 2 electric machines

� eCVT function possible with

planetary gear set installation

Advantages:

+ wide range of operating point adjustment

+ high regenerative braking rate

Disadvantages:

- partially unfavourable efficiency chain

- by eCVT an ICE power support through the electric motor required

- High costs

Examples:

• biggest fleet based on hybrid electric

vehicles from Toyota (in total 1 million

hybrid vehicles sold)

• Toyota „Hybrid Synergy Drive“ (Prius)

• „Lexus Hybrid Drive“ (LS 600h)


Series HybridHybrid Systems Introduction

� pure electrical power transfer

� minimum 2 electric machines

� no transmission

Advantages:

+ complete variable engine operating point

+ optimal operative strategy for fuel efficiency and exhaust emissions possible

+ maximum regenerative braking

Disadvantages:

- efficiency chain with high losses(ICE, generator, EM)

- approx. 3x installed power needed for permanent full load

- high weight

- high costs

- package

Examples:

• Renault Kangoo Elect‘road (electric vehicle

Kangoo Electri‘cite w/ Range Extender)

• PML Flightlink Mini QED (4x 120kW wheel-

hub motors)

• In application by ships (Pod-engine)


Power Split(front)

Parallel Hybrid(front)

conventional

Fuel efficiency 0 + +

Acceleration 0 + +

Comfort 0 + ++

Electric power 0 100% Approx. 300%

Costs 0 - - -

Source: according to M.Lehna (AUDI)

Comparison Full Hybrid SystemsHybrid Systems Introduction



Classification

Potentials of HEV



... Fuel Efficiency



Hybrid Powertrain FunctionalityHybrid Systems Introduction

Sourc

e: accord

ing to F

ord

Full

Hybrid

Mild

Hybrid

Mic

ro

Hybrid

rid

Full regenerative braking

Power assist (boost)

Stall protection

Torque smoothing

High speed cranking

Comfort cranking

Minimal regenerative braking

Electric accessory drives

Full power assist / electric drive

Operating point modification



Hybrid Systems

Potentials of HEV



... Fuel Efficiency



Comfort / Safety

PotentialsHybrid Systems Introduction

Extended Dynamics

Environment

� Increase in driving dynamics through boost function

� Torque Vectoring / enhanced heavy terrain drivability

� Fuel efficiency, reduced CO2 emissions

� Improved NVH behaviour

� Zero-emission and driving in congested areas

� Increase of HVAC comfort (A/C by standstill)

� Reduced NVH emissions

� Off-board-supply of electrical devices

� Active support of vehicle stability control systems (electric braking, torque vectoring)


PotentialsHybrid Systems Introduction

� Development and integration of new components and technologies for the automobile industry

� Electric motors, batteries, power electronics, etc.

� Innovative cross-linked powertrain control strategies

� Further development of the conventional gasoline and diesel ICE (downsizing, selective operating points)

� Energy management

� On-demand control of the accessory drives through electrification

� Efficiency improvement of the electric power generation for the electric loads

� Realisation of 4WD without transfer gear, differential, drive shafts (e4WD)

Technology / Innovation


City traffic(congested)

City traffic(flowing)

Overland/Highway

Gasoline vs. Diesel HybridsHybrid Systems Introduction

Increase in fuel efficiency in comparison to conventional gasoline powertrain

Source: GMb

ett

er

Diesel Hybrid

Dieselconventional

Mild-Hybridwith gasoline ICE

Ve

hic

le s

peed

Time Time Time

Full-Hybrid with gasoline

ICE

Power Split-Full-Hybrid with optimised ICE

Parallel Mild Hybridwithout optimised ICE

Depending on hybrid concept, ICE optimisation and driving cycle

Parallel Full-/ Mild-Hybrid with optimised ICE


Content




• Outlook



Selection of ArchitectureSimplified Proceeding

IAV analysis

Architecture Topology Selection

customer requirement e.g.

• power

• distance of operation

• noise

• cost

• identification of possible powertrain

configurations (of the shelf)

• decision matrix setup considering boundary

conditions

• e.g. serial, parallel,

• identify effort of modification

• e-cvt 1-mode, two-mode, combined parts

Performance

Topology

Functionality

Analysis

• % fuel saving

• functions

• …


Selection of ArchitectureSimplified Proceeding

IAV analysis

Database

Simulation / Velodyn

Process

• technology / supplier choice based on database

•proof of selected concept through simulation

(performance targets, ... )

•iteration step if needed

•modification of chosen off the shelf system by

combining certain solutions, e.g. asynchron instead

of synchron e-motor etc...


Hybrid Specific DemandsSafety

Standards and regu-lations also applicable for Hybrid Electric Vehicle

ISO 26262

EN 61508

R100

•High Voltage

isolation monitoring

active discharge

touch protection design

•Torque

securisation of all driver demands vs. actual

torque

•Functional

X - by wire etc

auto startup for battery charge


Content




• Outlook



� Simulation benefits

• Early prediction of the dynamic behavior

• Large modeling know-how for specific fields

of application

• Covers almost every domain

• Decreases the needs of physical prototypes

• Shortens the overall development time

MotivationSimulation in the development process

Source: IAV

� Challenges related to Hybrid technology

• Increases the powertrain complexity

• New opportunities for powertrain architecture

• Advanced control functions for energy

management and traction optimization

�� Objective: develop a cross-operating numerical

solution to investigate the entire vehicle performance

offered by complex hybrid strategies


Continuous Use of SimulationSimulation in the development process

� Integration into the product development

process

• Support of the project decision phases

• Functions validation and testing

• CiL and HiL simulation

• Debugging supportConcept selection

Requirements

specifications

Design

specifications

Realization

Testing phase

Prototypes

Phases of the development process

� Requirements on the simulation concept

• Be fully configurable and standardized

• All the components or modules

developed should be easy to combine

• Clear separation between physical

models and control units models

• Possibility to simulate the function of

each component on its own as well as in

the overall vehicle


Missions of the Simulation ApproachSimulation in the development process

� Concept studies of E-machine, converter, battery

� Reduction of losses of the mechanical components

� Demand controlled auxiliaries (Thermal

management, X-by-Wire)

� Operating strategy

� Synchronization of ICE and electric drive

operation

� Energy management and energy recovery

� Topology studies

� Engine concept

� Torque investigations

� Fuel consumption, Emissions

Powertrain Concept

Electrical Concept & Auxilliaries

Powertrain & Energy Management

ANALYSE

DESIGN

TEST EARLY

OPTIMISE


Modular & Flexible Simulation StrategySimulation in the development process

� Model Based design

• Possible Cooperation work in components modelling

• Modularity and potential of reuse

• High reactivity to updates

• Easy maintenance of complex systems

�� VeLoDyn - Vehicle Longitudinal Dynamics

Increased Complexity

� Modelling of any type of powertrain

• Any powertrain architecture can be modelled (front wheel drive, 4x4, serial hybrid, parallel hybrid, …)

� Variable modelling level

• Level of components details � Trade off between simulation / development speed and accuracy of results

� Direct hardware integration

• Direct C compilation possible (i.e. for HiL tests)


Description of a Simulation-Based Decision ProcessSimulation in the development process

BackwardBackward simulationsimulation

Customer Customer

needsneedsMission profilesMission profiles

PowertrainPowertrain designdesign

PowertrainPowertrain first first sizingsizing

ForwardForward simulationsimulation


Distributed Simulation for System InvestigationsSimulation in the development process

Distributed Simulation Concept

• Linking domains of chassis and

powertrain control

• Consideration of lateral dynamics in

HEV powertrain development

• Use of non-local SW-licenses

• Reduction of computation time by

distributed simulation

• Use of each simulation tool's native

environment

• Function development for global

chassis control

• Integration of electrical components

into HEV powertrains

• Functional validation

Powertrain model

• detailed Powertrain model representing hybrid architecture and contains

operational strategy

• detailed vehicle chassis model

• detailed environmental description including a

maneuver controller for longitudinal/lateral maneuver

setup

veDYNA

Vehicle model

• detailed vehicle chassis model

• detailed environmental description including a

maneuver controller for longitudinal/lateral maneuver

setup

veDYNAveDYNA

Vehicle model

Use of EXITE-ACE as co-simulation tool to connect IAV-powertrain model VeLoDyn and

common handling simulation tool veDyna

Integration tool

Tool adapter for MATLAB®, Simulink®, Real-Time Workshop®; TargetLink, ASCET, Dymola, Rhapsody®in C, Rapsody® in C++, C/C++ …



Integration tool



Integration tool

Tool adapter for MATLAB®, Simulink®, Real-Time Workshop®; TargetLink, ASCET, Dymola, Rhapsody®in C, Rapsody® in C++, C/C++ …


Content




• Outlook


� Hybridization & impact on stability

� Enhanced driving dynamics


Content




• Outlook


�� Hybridization & impact on stability

� Enhanced driving dynamics


Powertrain Hybridization – Impact on Stability Torque distribution with E-machine integration

1. Propulsion mode

� Applying / superimposing drive torque

2. Generator mode

� Applying / superimposing drag torque

3. Combined operations with at least 2 E-machines

� Power transfer between axles and wheels (directly or

battery buffered)

E-machine potential operating modes:

A non-adapted torque distribution can lead to a clear vehicle instability


Powertrain Hybridization – Impact on StabilityIntegration of E-machines in conventional powertrains

Fundamental system characteristics:

� Maintain the speed / torque coupling between axles

(wheels)

� The effect of the regeneration process is similar to an

additional drag torque

� ASR/MSR brake interventions always act on both

axles

Remark:

� AWD stability condition: traction tendency


Fundamental system characteristics:

� No mechanical coupling between axles or wheels!

� Possible superimposition of wheel individual

(failure-) regeneration torque

� ASR/MSR brake interventions not automatically

distributed on both axles

Challenges:

� Safety relevant aspects related to torque

distribution

� Consideration of all potential failures and

associated failsafe modes

Powertrain Hybridization – Impact on StabilityIntegration on individual axles - Virtual AWD


Powertrain Hybridization – Impact on StabilityPotential Hybrid strategy

• Battery charging during normal driving

• Basic Recuperation

(engine drag torque superposition)

• Brake recuperation (system blending).

• Transmission shift support (boost)

• Driving with E-machine only

• 4WD-strategy and rear axle boost

Virtual AWDBattery buffered

• Safety strategy for:

– Driving with E- machine in a “fail-safe“ mode

– Erroneous Torque set-point / sign

– Slip intervention (ASR/MSR)

– ESC and ABS intervention

Toyota Prius battery pack


Powertrain Hybridization – Impact on StabilitySimulation settings for a real 3D track definition

3D-Two-Lane Alped’Huez road profile

Vehicle parameterization

Advanced driver settings and road conditions

The representativity of the model

needs to be verified through

comparison with physical data

� Validation process

Vehicle Model w/ lateral dynamics consideration

Detailled modelling of chassis kinematics, driver

reaction and road definition.


Powertrain Hybridization – Impact on StabilityValidation process

Vehicle system tests & validation

� Tests definition according to driving

manoeuvres for qualitative and

quantitative evaluation (standards,

customer specific, certification criteria)

� Networking and diagnostics tests

� Mechanical and parametrical

calibration

� Data base management w/ self-

developed tools (IAV CalGuide)

� Various high-end measuring systems

and robotics

� Trained and experienced test &

calibration engineers


Powertrain Hybridization – Impact on StabilityValidation process – vehicle instrumentation


Powertrain Hybridization – Impact on StabilitySimulation settings for a real 3D track definition

3D-Two-Lane Alped’Huez road profile

• Front and rear E-Machine

scaled from longitudinal

optimization

• Driver used form veDyna except

gear shifting

• All hybrid functions enabled

• SOC at start: 70 %

• 4WD torque split strategy:

1. As much as possible with

front axle, then add rear

axle

2. Permanent 4WD support

SOC dependent

• ASR on

• MSR on/off

Vehicle parameterization

Advanced driver settings and road conditions


Powertrain Hybridization – Impact on StabilityVehicule behavior while regenerative braking

160 seconds on the road

MSR / ESC off

Up-hill drive with maximum recuperation torque at rear axle


Content




• Outlook


� Hybridization & impact on stability

�� Enhanced driving dynamics


Enhanced driving dynamics through Torque-VectoringRear axle differential with active torque distribution

MRad

Understeering driving behavior without active torque distribution

Active longitudinal and lateral torque distribution

Positive effect on

• Traction

• Critical cornering speed

• Self-steering response

• Handling and cornering characteristics

• Agility

• Yaw damping / yaw boosting

• Reducing brake intervention


Enhanced driving dynamics through Torque-VectoringRear Axle differential with active torque distribution

Open differential

Wheel-specific torque vectoring

• Existing engine/transmission configurations (MT, AMT, DCT, CVT, AT) can be carried over

• Rear-axle module: supplier add-on

• Utilization of wheel-specific coefficient of friction

Integration of two electric machines in the differential casing

Control

Compact electric machines

Using a suitable storage system

• Parallel hybrid

• Improved longitudinal dynamics

• Avoidance of traction interruption

Energy storage

Optional for hybrid capability


Enhanced driving dynamics through Torque-VectoringTorque-Vectoring functionality

µ low

1000 N

350 Nm350 Nm

i = 4

175 Nm

Moving off with µ-split

µ high

1000 N

Mechanical torque transmission superimposed by electrical power flow when necessary

TV torque of 700 Nm for

• optimizing traction

• influencing transverse dynamics

independently of drive torque

350 Nm350 Nm 350 Nm

Generator mode

E-machine mode

350 Nm+700 Nm

1000 N+2000 N

175 Nm+175 Nm


Enhanced driving dynamics through Torque-VectoringSimulations results of lateral dynamics ISO 4138

Steady-state skid-pad

driving R = 100 m(test to ISO 4138)

E-m

ac

hin

e t

orq

ue

le

ve

lsS

tee

rin

g a

ng

le

Lateral acceleration

area of optimizing control

linearization gain approx. 30%

lateral acceleration gain approx. 5%

2 x 350 Nm

2 x 230Nm

Self-steering

response impact

� predictable driving behavior also on upper lateral acceleration

� increase the speed of cornering

� possibility to recuperate transversal dynamics energy

� possibility to realize a lane keeping system

Steer. angle w/o el. hyb. PowertrainSteer. angle w/ el. hyb. powertrain

Torque, leftTorque, right


Enhanced driving dynamics through Torque-VectoringSimulations results of lateral dynamics ISO 7401

Step steering-angle

change from0 to 50° (300°/s at 80 km/h,

test to ISO 7401)

E-m

ac

hin

e t

orq

ue

le

ve

lsY

aw

ra

te

Time

½ steering angle

Steering angle

Overshoot reduced from13% to approx. 2%

area of optimizing controlpeak response time reduced by approx. 30%

Driving dynamics

impact

� low response time by fast actuator speed (~10 ms)

� enhancement of steering response (yaw rate gain)

� reduction of undesired yaw rate response (yaw rate damping)

� reduction of body motion

Yaw rate w/o el. hyb. powertrain

Yaw rate with el. hyb. powertrain

Torque, left

Torque, right


Enhanced driving dynamics through Torque-VectoringSimulations results of lateral dynamics FMVSS 126

Sine with dwell for

6.5xA(test to FMVSS 126)

Driving stability

impact

� impact of tracking stability

� vehicle stabilization without braking

� increase of driving dynamics by pre controlled intervention

Tra

nsvers

al deflection

Yaw

rate

vs. m

ax.

.Y

aw

rate

Time

Oversteer criterion

Understeer criterionSteering input

E-m

achin

e t

orq

ue levels

Yaw

rate

Ste

ering a

ngle

l

Time

Time

Yaw rate response

Yaw deflection

Yaw rate w/o el. hyb. powertrain

Yaw rate w/ el. hyb. powertrain

Torque, left

Torque, right

position w/o el. hyb. powertrain

position with el. hyb. powertrain

w/o el. hyb. powertrain

with el. hyb. powertrain


Enhanced driving dynamics through Torque-VectoringCombined system layout optimisation

Installed Total Torque in Nm

Ya

w r

ate

devia

tion (a

bs.)

2 x 20kW

2 x 30kW

Consumption potential from longitudinal dynamics

Influence of additional torques for stabilizing potentialBased on: FMVSS 126 at max. steering angle amplification

Simulated Vehicle category: SUV, (not fully verified)


� Advantages of Simulation (Co-Simu)

• supports every phase of the development process

• covers all levels, from component to system

• functional development support and testing

• hybrid strategy verification (torque distribution,

regeneration…)

• influence of HY specific functions on vehicle stability

• supports safety analysis and failsafe modes definition

Pix

elioSimulation in the Development Process of Hybrid Powertrains

� Characteristics of the simulation concept

• Fully configurable and standardized

• Easy combination of all the components or modules

developed

• Clear separation between physical models and control

units models

• Possibility to simulate the function of each component

on its own as well as in the overall vehicle

• Re-use of former models for spin-off projects


Content




• Outlook



Perspectives in HEV TechnologiesUltimate Obejctive: Zero Emission

What kind of vehicle do I need?

PEV readiness report by

Roland Berger Consulting:

„…cities and other stakeholders

should educate and prepare

consumers to accelerate PEV

transition from niche toy of the

elite to mass market…”

Individual mobility perspective:

„lease / rent by actual need“

Driving Range?


Perspectives in HEV TechnologiesDriving range distribution

Estimation of the daily average range

(source MTZ 10/2009 volume 70):



Driving Range?

Energy supply network?

Home-plug (AC) Fast charge (DC) Inductive Energy



Driving Range?

Energy supply network?

Costs of ownership?

How to support E-mobility expansion on the market?

�� By keeping advantages of E-traction and to get rid of inconvenient.


Perspectives in HEV TechnologiesStatus & IAV‘s vision

CO2 emission

baseline

Conventional

Luxury & SUV

Class E, F

Compact & medium vehicles

Class B, C, D

Urban vehicles

Class A100

0

Target � Pure EV - Electric Vehicles

� Requires significant changes in energy storage technologies (i.e. batteries)

and / or charging technology and infrastructures

Full electric

* Ta

nk to

whe

el

100%*

Micro-hybrid

Mild-hybrid Full-hybrid

Double drive

Full-hybrid

Single shaft

Parallel HEV

4-10%10-20%

20-50%20-40%

Stop & Start

E-axle

Integrated

e-machine

BISG

Need an affordable alternative to compensate the actual technology gap, satisfy the

customers needs and environment policies

?


Perspectives in HEV TechnologiesStatus & IAV‘s vision

CO2 emission

baseline

Full electricConventional

* Ta

nk to

whe

el

Luxury & SUV

Class E, F

Compact & medium vehicles

Class B, C, D

Compact vehicles

Class B, C

Urban vehicles

Class A100

0

Micro-hybrid

Mild-hybrid Full-hybrid

Double drive

Full-hybrid

Single shaft

100%*

Parallel HEV

Range Extender

Series HEV

50-90%*

Plug-in

Serial hybrid plug-in architecture:

Two mission profiles :

� Long range application

�� Urban application

4-10%10-20%

20-50%20-40%

Stop & Start

E-axle

Integrated

e-machine

BISG

Excellence in Automotive R&D

Merci

Olivier Imberdis

IAV France

70-80 Rue des Champs Philippe - 92250 La Garenne-Colombes4 Rue Guynemer - 78280 Guyancourt

[email protected]

Documents

Excellence in Automotive R&Dturbo-moteurs.cnam.fr/publications/pdf/conference1_2011.pdf · Excellence in Automotive R&D Hybrid Electric Vehicles Development Processes & Challenges