Powertrain Thermal Modeling · 2015-08-20 · 16 Powertrain Thermal Modeling | A. Oberting | 20.10.2014 To simulate the complexity in thermal behaviour of an internal combustion engine

Powertrain Thermal Modeling A. Oberting, Dr.-Ing. M. Auerbach, Dr.-Ing. S. Grams,

Prof. Dr.-Ing. Michael Bargende

20.10.2014

2 Powertrain Thermal Modeling | A. Oberting | 20.10.2014

Thermal behavior of hybrid powertrains

Cooperation-Professorship: Prof. Dr.-Ing. Michael Bargende Postgraduate: Hr. Andreas Oberting

Department: Powertrain Concepts Modeling & Simulation Projekt Manager Audi: Dr.-Ing. Michael Auerbach


Outline

► Motivation of Hybrid Powertrain Simulation

► Strategy of a Modular Simulation System

► Powertrain Thermal Modeling

► Thermal Engine Models

► Lubrication Models

► Conclusion & Outline


Trade-off in Hybrid Powertrain Simulations

High Level

Level of Accuracy

Modeling Effort Simulation Time

Input/Output Scaling-Modell

AI

ECU

HiL- Application

Measurement & Validation

t T=20°

T=40°

T=90°

pmr

Model

A

B

C

Low Level

Target

High Level

Challenges

Early stage of development No real components No basis measurements

High Level


Thermal Powertrain Network

Hybrid Powertrain

Disciplines in Hybrid Powertrain Simulations

High Voltage -Battery

EC Electric

Components

• Motor/Generator • Power Electronics • Battery System

CS Control- strategy

• Start / Stop • Recuperation • Load Shifting

GB Gearbox

• AT / DC / MT • Clutch modeling • Thermal behavior

ICE Combustion

Engine

• Engine Performance • Thermal-Energy-Management • Lubrication


AS Powertrain

ICE Combustion Engine

GB Gearbox

EC Electric

Components

CS Control- strategy

Modular Simulation System Model-Library

TD Thermo-

dynamics

AT Exhaust-After-treatment

ECU Control Unit

MEC Mechanic

TM Thermal Behavior

TCU Control Unit

MEC Mechanic

TM Thermal Behavior

EM,LE electr., mech., therm., funct.

CS Control- Strategy

A A

4 (bis 10)- Massen- Netzwerk mit Rückkopplung B B

Reibmodell n-Führungs- Temperaturen

Trägheit

Mehrmassen- Netzwerk

0D–KKL

0D-ÖKL C C

Prädiktives Reibmodell

(detaillierte Mechanik)

Trägheit

Mehrmassen- Netzwerk

1D –KKL

1D-ÖKL D D

Reibkennfelder

Trägheit

Temperatur- Vorgabe

Reibmodell 1-Führungs- Temperatur

Trägheit

A

C

B

D D

C

A A

D

B B

C

A

B

C

D

A

B

C

D

A

B

C

D

Le

ve

l o

f A

ccu

ran

cy

A

B

C

D

MEC Mechanic

TM Thermal Behavior

4 (to 10)- Multi Mass Network

Friction model incl dynamic considerations

Multi Mass Network

0D –CS

0D-OCS

Predictive Friction Model

Multi Mass Network

1D –CS

1D-OCS

Static map

„Warmed up“

Temp. Var

„demand- temperatures

Friction model incl. transient warm-up


AS Powertrain

ICE Internal Combustion Engine

Thermal Powertrain Modeling Aims of different Accurancy Levels

Temperatur- Vorgabe

4 (bis 10)- Multi mass

Network

Multi mass Network

0D –CS

0D-OCS

Multi mass Network

1D –CS

1D-OCS

TM thermal

behavior

„demand- temperatures“

Motormasse

Kühlkreislauf

Öl (therm. Masse)

Luft

Kraftstoff

Abgas

Wandwärmeverluste

kWQW

A

B

C

D

Tim

eli

ne

Level A (T4-Model)

• Investigations of different hybrid powertrains in a wide range

Heat loss calculation with the use of the first law of thermodynamics

Level B (Multi-Mass Model)

• Designed for individual engine • Examination of different hybrid powertrains and their

warm-up strategies

Calculation neededs a measured heat loss map

Important:

• focus on the main heat flows – no modeling of single parts

Level C/D (FE-Modell)

• Interaction of components with oil/cooling circuit (engine, turbo, E-Drive, …)

• Optimization focussed on whole powertrain

Physical determination of wall heat loss and wall temperature calculation


Warm-up Strategies based on a Functional Cooling System

Simulation Frame Cabin-Heater

Turbocharger

Main Radiator

► The cooling system is the

groundwork for a transient

warm up simulation

► Integrated rotary-valve

controller to simulate

different strategies

► The modular design allows to

switch easily from simple to

detailed thermal engine

models

Heat Exchanger Oil/Coolant

Thermal Engine Model

Rotary Valve-Controller

Gearbox Oil Cooler


Warm-up Strategy with Rotary Valve Simple Thermal Mass Model

Standing Water

Mini-Vol.-Flow

Oil Cooler

Radiator Bypass

T_Mass-

Cyl_Head

T_Mass-

Cyl_Block T_Mass

Heat

Exchanger

Water Pump

T_Mass-

Oil

Oil Cooler

Start Warmup

Radiator-valve opens before water pump

T_Mass-

Liner

Rotary-Valve


0 50 100 150 200 250 300 350 400 450 500 550 600

Zeit [s]

Te

mp

era

tur

[°C

]

0

10

20

30

40

50

60

70

80

90

100

110

120

Dre

hsch

iebe

r [°

]

40

60

80

100

120

140

160

180

200

T-OIL gemessen

T-OIL Steuergerät

T-OIL Filtersimulierte Öltemperatur

Drehschieber

Results: Static warm up 1900/1,4 bar

Standing Water

Mini Volume Flow Oil- Cooler

Rota

ry V

alv

e A

ngle

[°]

Te

mp

era

ture

[°C

]

Rotary Valve

T-Oil Measurement

T-Oil Simulation

T-Oil Filter / ECU

Time [s]

20°C

90°C

► Measurements are the base for the validation

of thermal engine models

► Important is the relevant temperature for

the friction calculation


Te

mp

era

tur

[°C

]

20

30

40

50

60

70

80

90

Interaction between Thermal Model and Friction Model

CT FilterOil _

CT HeadCyl _

Oil Filter

Oil ECU

Oil Sump

T=20°

T=40°

T=90°

pmr

T=20°

T=40°

T=90°

pmr

fmep, Head

T=20°

T=40°

T=90°

pmr

fmep, Block

„Friction CO2“

fmep, all

1.Warm-up Measurements

CT SumpOil _

fmep, AC

3.Friction Model

fmep=f(T??)

2.Thermal Engine Model

► For further evaluation regarding CO2 potential, the friction model must

be adjusted to the temperatures of the thermal model

► No constitution of every flushing process

► Important is the relevant temperature for the engine friction

Important: Validation of thermal models with temperatures at relevant position for the engine friction

Oil Filter

Oil ECU

Oil Sump


ICE Combustion Engine

Powertrain Friction Modeling Model-Library

previously current development process future

Level -1: „warmed up“ ► Static map

Level 1: „Transient Warm-up“ ► Friction temperature bounded to

components ► Expanded measurements

Level 3: „Material dynamic“

► Evaluation of thermal

expansion

Level 0: „Temp. Variation“ ► Static map f(T)

T=20°

T=40°

T=90°

pmr

Level 2: „Dynamic consideration“ ► Lubrication oil film ► Dynamic temperature progression

Friction model incl. transient

warm-up

Friction model incl dynamic

considerations

Predictive Friction Model

MEC Mechanic

Static map

„Warmed up“

Temp. Var. A

B

C

D

Standard procedure in combination of measurements and simulation

„today“

Re

ibm

itte

ldru

ck p

mr [N

m]

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Temperatur [°C]

0 1000 2000 3000 4000 5000 6000 7000

Schleppmessung bei 90°CFriction

D2 [mm]

s [m]

D1 [mm]

… etc.

Material

Fe,

Al,

Mg

3_EF

FMO

M3

[Nm

]

-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

2

4

6

8

10

3_DRZ3 [1/min]

0 20 40 60 80 100 120 140 160 180 200-1000

0

1000

2000

3000

4000

5000

6000

0dt

dn


Re

ibm

om

en

t M

R [

Nm

]0

2

4

6

8

10

12

14

16

18

20

22

Drehzahl [1/min]

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Nebenaggregate Vakuumpumpe Kraftstoffpumpe HDP Ölpumpe Wasserpumpe Ventiltrieb Triebwerk

Re

ibm

om

en

t M

R [

Nm

]

0

2

4

6

8

10

12

14

16

18

20

22

Drehzahl [1/min]

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Nebenaggregate Vakuumpumpe Kraftstoffpumpe HDP Ölpumpe Wasserpumpe Ventiltrieb Triebwerk

Temperature-Dependent Friction Measurements Static Friction Parts

35°C 90°C

pK

KD

rpm [1/min]

VT

+A

C

PG

& M

B

VT

+A

C

FM

EP

FM

EP

Pis

ton

Gro

up

/ M

ain

Be

ari

ng

rpm [1/min] rpm [1/min] rpm [1/min]

Standard Measuring Method

Switch of piston cooling jets at 2500 [1/min]

Switch of low/high pressure rate at 4500 [1/min]


► The main part of temperature-dependent friction is coupled to crankshaft and piston group friction

Use of cooling jets raises the temperature dependency

Re

ibm

om

en

t M

R [

Nm

]0

2

4

6

8

10

12

14

16

18

20

22

Drehzahl [1/min]

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Rest-Anteil 35°C Rest-Anteil 90°C Triebwerk

Re

ibm

om

en

t M

R [

Nm

]

0

2

4

6

8

10

12

14

16

18

20

22

Drehzahl [1/min]

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Rest-Anteil Triebwerk

Temperature-Dependent Friction Measurements Static Friction Parts

35°C 90°C

VT

+A

C

FM

EP

FM

EP

rpm [1/min] rpm [1/min]


Te

mp

era

ture

[°C

]

FM

EP

[b

ar]

Time [s]

Te

mp

era

ture

[°C

]

FM

EP

[b

ar]

Time [s]

Friction Models used in Powertrain Simulation

CT BearingMain

CT HeadCyl ,

CT SumpOil

FMEP Simulation Method I

FMEP Measurement

FMEP Simulation Method II

Changes in the FMEP-Map after 20°C

0°C

600

20°C

I. Standard friction model T_oil_sump

II. Expanded friction model seperate cyl head and block calculation


► To simulate the complexity in thermal behaviour of an internal combustion engine

detailed models are required

► Consequences for the thermal behavior of a hybrid powertrain model

► Simple approaches generate good results depending on

the application area e.g.: HiL, forecasts of CO2 Emission

► Identification and usage of friction-dependent temperatures for validation and

friction modeling main bearing & piston group

► Future Steps

► Combination of high level detailed thermal models and the hybrid powertrain

models

► Evaluation of split-cooling-concepts by separation of oil- and coolant-

temperatures in friction modeling

Conclusion & Outlook

Thank You.

Documents

Powertrain Thermal Modeling · 2015-08-20 · 16 Powertrain Thermal Modeling | A. Oberting | 20.10.2014 To simulate the complexity in thermal behaviour of an internal combustion engine