holistic engine and eat system simulation from concept to ......throttle and combustion calibration...

Holistic Engine and EAT System Simulationfrom Concept to Series Development

GT Conference 2018

8. October 2018, Frankfurt am Main

Martin Weber, Dr.-Ing. Reza Rezaei, Rico Möllmann, Hendrik Rauch, Dávid Kovács and Christopher Hayduk

Agenda

• Model-based development process

• Virtual field test and evaluation

• Conception with holistic system approach

• Series calibration support

• Summary & Conclusion

IAV 10/2018 TPC1 MW2 Status: released for GT conference2

Agenda







Model-based development process

Concept Development Phase

Focus: Functional Feasibility

Detailed Design

Requirements Analysis

Integration TestingSystem Conception

by CAE

Concept Implementation

System Testing

Module Testing Production Planning

Requirements Refinement

Integration TestingFinal Series Design

Series Implementation

System Testing

Module Testing

Series Development Phase

Focus: Series Production Robustness

Re-use of detailed

concept phase models

Model-based engine and exhaust aftertreatment calibration

Continuous feedback of test results for validation and fine-tuning of component and system models


Agenda







Virtual field evaluation and test


• Various applications of commercial engines must comply with RDE legislation

• Operation under high-altitude or extreme ambient temperature conditions

• Evaluation of engine calibration in critical field cycles

• Investigation of the effect of thermal management strategies

Main Challenges

• Exhaust temperature increase without fuel consumption deterioration

• Effect on raw emissions as well as EAT performance (NO2/NOX, space

velocity) requires further investigations

• Some field problems (DOC clogging, DPF ashing, etc.) can mostly only be

estimated

MA

N-I

AV

: „V

ari

ab

le v

alv

e tra

ins in

HD

en

gin

es”,

11

th M

TZ

Cha

rge

Exch

an

ge

Con

f, 2

01

6

Holistic system simulation for evaluation of engine and EAT functions

Optimization of thermal management and EAT efficiency for various

applications

On-highway

Hoh

l, Y

ve

s:

“Lie

bh

err

exp

eri

en

ce

with

SC

R o

n f

ilte

r syste

m”,

SA

EH

D S

ym

po

siu

m 2

01

6

Off-highway

Agenda







Conception with holistic system approach

Engine model with predictive combustion and NOx model can replace investigation on test bench

Coupled simulation system enables holistic statement about system behavior in different load cycles

Engine test bench

GT-SUITE engine model

Inlet boundary:

• Exhaust mass flow

• Exhaust gas temp.

• Concentrations

Coupling to

EAT models

GT-SUITE EAT models


…

End of pipe

emissions

En

gin

e s

pe

ed

[-]

0.2

0.4

0.6

0.8

1.0

No

rma

lize

d c

um

ula

ted

va

lue

s [-]

0.0

0.1

0.2

0.3

0.4

0.5

Cold start validation cycle time [s]

0 120 240 360 480 600 720 840 960

Cumulated NOx mass Cumulated fuel mass Cumulated exhaust gas mass

Measurement

Simulation

Te

mp

. L

P-

Tu

rbin

e o

ut

50K

En

gin

e to

rqu

e [-]

0.0

0.2

0.4

0.6

0.8

1.0 Measured Simulated



Engine model

• 12l-HD diesel R6 engine

• 2100 bar CR DI injection

• EGR-emission concept

• Physical modelling approach to ensure predictability

• DI-Pulse combustion model

• IAV-NOx kinetic* implemented as user code reference

• Cold start cycle used to validate the correct behavior

in terms of:

• Torque

• Temperature after low-pressure turbine

• Cumulated NOX mass

• Cumulated exhaust gas mass

Rau

ch

, H

., R

eza

ei, R

., W

eb

er,

M.,

Ko

va

cs, D

. e

t a

l., “H

olistic D

eve

lop

me

nt

of F

utu

re L

ow

NO

x

Em

issio

n C

on

ce

pts

fo

r H

ea

vy-D

uty

Ap

plica

tio

ns,”

SA

ET

ech

nic

al P

ap

er

20

18

-01

-17

00

, 2

01

8

Rezaei, R., Dinkelacker, F., Tilch, B., Delebinski, T., et al., “Phenomenological modeling of combustion and NOX emissions

using detailed tabulated chemistry methods in diesel engines," International Journal of Engine Research 17(8):846-856.

*

Te

mp

. D

OC

in

Measurement Simulation

50K

Cu

mu

late

d N

Ox

tailp

ipe

em

iss

ion

s [

-]

0.0

0.2

0.4

0.6

0.8

1.0

1.2

WHTC cycle time [s]

0 300 600 900 1200 1500 1800

Te

mp

. D

PF

in

50K

Te

mp

. S

CR

in

50K

Baseline aftertreatment system model

• Baseline EAT system with: DOC + DPF + SCR

• Temperatures at DOC, DPF and SCR inlet

show good match to measured temperatures

• AdBlue dosing strategy was implemented as

soft ECU

• Differences in SCR efficiency caused by a

different SCR technology used for validation



Rau

ch

, H

., R

eza

ei, R

., W

eb

er,

M.,

Ko

va

cs, D

. e

t a

l., “H

olistic D

eve

lop

me

nt

of F

utu

re L

ow

NO

x

Em

issio

n C

on

ce

pts

fo

r H

ea

vy-D

uty

Ap

plica

tio

ns,”

SA

ET

ech

nic

al P

ap

er

20

18

-01

-17

00

, 2

01

8



DOC DPF SCR

Size [liter] 10.3 26 32

Catalyst technology Pt - Cu-zeolite

Max. NH3 storage [g/l] @ 250 °C - - 1.57

Cell density [cpsi] /

wall thickness [in]

300/

0.006

200/

0.012

300/

0.006

SCRF SCR

Size [liter] 26 5

Catalyst technology Cu-zeolite Cu-Zeolite

Max. NH3 storage [g/l] @ 250 °C 1.57 1.57

Cell density [cpsi] /

wall thickness [in]

200/

0.012

300/

0.006

Stage V baseline EAT system Stage V SCRF + SCR EAT system

• Comparison of two EAT layouts and technologies

• Baseline Stage V system

• SCRF + SCR layout

• Cu-zeolite SCR technology

• Both layouts have the same downpipe length

• Equal SCR size for both layouts

• Equal maximum NH3 of all SCR catalysts

• NH3 storage is initialized empty in all simulations

Rau

ch

, H

., R

eza

ei, R

., W

eb

er,

M.,

Ko

va

cs, D

. e

t a

l., “H

olistic D

eve

lop

me

nt

of F

utu

re L

ow

NO

x

Em

issio

n C

on

ce

pts

fo

r H

ea

vy-D

uty

Ap

plica

tio

ns,”

SA

ET

ech

nic

al P

ap

er

20

18

-01

-17

00

, 2

01

8



Engine results

• Intake throttling is enhanced by an EGR cooler

bypass during the cold start only

• Intake throttling during low loads increases the

exhaust gas temperature throughout the load cycle

• EGR cooler bypass increases the exhaust gas

temperature and engine out NOx emissions

Fastest EAT heat up expected with cold start

optimized combustion calibration + intake

throttle + EGR cooler bypass

Cold start NRTC

En

gin

e s

pe

ed

[rp

m]

600

1000

1400

1800

2200

En

gin

e t

orq

ue [

Nm

]

-500

0

500

1000

1500

2000

2500

Tem

p.

LP

-tu

rbin

e

ou

t [d

eg

C]

050

100150200250300350400

NRTC cycle time [s]

0 300 600 900 1200

EGRcBypass

Comb. cal. 1 Comb. cal. 2 Comb. cal. 2 + intake throttle

Comb. cal. 2 + intake throttle + EGRcBypass

Comb. cal. 2 Comb. cal. 1

Rau

ch

, H

., R

eza

ei, R

., W

eb

er,

M.,

Ko

va

cs, D

. e

t a

l., “H

olistic D

eve

lop

me

nt

of F

utu

re L

ow

NO

x

Em

issio

n C

on

ce

pts

fo

r H

ea

vy-D

uty

Ap

plica

tio

ns,”

SA

E T

ech

nic

al P

ap

er

20

18

-01

-17

00

, 2

01

8

• Comb. cal. 1: High efficiency mode, low exhaust

gas temperature as “normal operation”

• Comb. cal. 2: Retarding of SOI and lowering of

boost pressure as heating measures

Baseline EAT results

• SCR storage initialized as empty

• Limited AdBlue dosage release at 200°C at SCR

inlet to prevent blocking

• AdBlue dosing with pre control & NH3 storage

controller

• NOx reduction by approx. 40% achieved with intake

throttle and combustion calibration 2



Fast heat up of EGR cooler bypass can’t

compensate the higher raw NOx emission

Rau

ch

, H

., R

eza

ei, R

., W

eb

er,

M.,

Ko

va

cs, D

. e

t a

l., “H

olistic D

eve

lop

me

nt

of F

utu

re L

ow

NO

x

Em

issio

n C

on

ce

pts

fo

r H

ea

vy-D

uty

Ap

plica

tio

ns,”

SA

ET

ech

nic

al P

ap

er

20

18

-01

-17

00

, 2

01

8 Te

mp

. S

CR

in

[d

eg

C]

100

150

200

250

300

350

AdBlue dosage release

SC

R N

H3

sto

rag

e l

eve

l [g

/l]

0.0

0.10.20.30.40.50.6

Comb. cal. 1

Comb. cal. 2 Comb. cal. 2 + intake throttle Comb. cal. 2 + intake throttle + EGRcBypass

Cu

mu

late

d N

Ox t

ail-

pip

e e

mis

sio

ns

[g

]

05

10152025303540

NRTC cycle time [s]

0 300 600 900 1200

871 mg/kWh

680 mg/kWh569 mg/kWh

514 mg/kWh

Cold start NRTC

SCRF + SCR EAT results

• NH3-slip over SCRF is needed to distribute NH3 to

the SCR

• After cold start, thermal management is needed to

prevent the EAT from cooling down



Rau

ch

, H

., R

eza

ei, R

., W

eb

er,

M.,

Ko

va

cs, D

. e

t a

l., “H

olistic D

eve

lop

me

nt

of F

utu

re L

ow

NO

x

Em

issio

n C

on

ce

pts

fo

r H

ea

vy-D

uty

Ap

plica

tio

ns,”

SA

ET

ech

nic

al P

ap

er

20

18

-01

-17

00

, 2

01

8

Te

mp

. S

CR

F in

[d

eg

C]

050

100150200250300350

AdBlue dosage release

Comb. cal. 1

Comb. cal. 2 Comb. cal. 2 + intake throttle Comb. cal. 2 + intake throttle + EGRcBypass

SC

RF

NH

3 s

tora

ge

lev

el

[g/l

]

0.00

0.05

0.10

0.15

0.20

SC

RF

NH

3 s

lip

[p

pm

]

0

50

100

150

200

250

SC

R N

H3

sto

rag

e le

vel

[g/l

]

0.00.10.20.30.40.50.60.70.8

SCRF NH3 slip

leads to NH 3

storage in SCR

Cu

mu

late

d N

Ox t

ail

-p

ipe

em

iss

ion

s [

g]

0

510152025

30

NRTC cycle time [s]

0 300 600 900 1200

700 mg/kWh

570 mg/kWh

382 mg/kWh

377 mg/kWh

Fast heat up of EGR cooler bypass can’t

compensate the higher raw NOx emission

Baseline EAT: 514 mg/kWh

SCRF + SCR EAT: 377 mg/kWh

- 27 %

Cold start NRTC



Conclusion

• In a coupled simulation environment, different

thermal management measures can be

investigated

• The effect on different EAT systems and

therefore deNOx efficiency is clearly visible

• SCRF systems can improve the trade-off

between fuel consumption and NOx emission

The NOX-/be trade-off can be loosened by

the investigation of different EAT layouts

230

232

234

236

238

300 400 500 600 700 800 900

Fu

el c

on

su

mp

tio

n [

g/k

Wh

]

NOx tailpipe emissions [mg/kWh]

Baseline EAT

SCRF + SCR

Cold start NRTC

Rau

ch

, H

., R

eza

ei, R

., W

eb

er,

M.,

Ko

va

cs, D

. e

t a

l., “H

olistic D

eve

lop

me

nt

of F

utu

re L

ow

NO

x

Em

issio

n C

on

ce

pts

fo

r H

ea

vy-D

uty

Ap

plica

tio

ns,”

SA

ET

ech

nic

al P

ap

er

20

18

-01

-17

00

, 2

01

8

Comb. cal. 1Comb. cal. 2

Comb. cal. 2 + intake throttle

Comb. cal. 2 + intake throttle + EGRcBypass

Agenda







Series calibration supportCalibration of DPF soot load detection

• Calibration of the ECU DPF soot

load detection nearly impossible

without physico-chemical models

• Passive and active regeneration

are modelled physico-chemically

in GT-Suite

• Model-based calibration of the

ECU functionality

• Validation of the models against

DPF weighting on engine test

bench is necessaryEngine or catalytic

test bench

Pre-calibrated

ECU model

3: Optimization of the

ECU model

Endurance

run with DPF

weighting

1: Calibration of the

physico-chemical model

2: Calibration of

fast- running

ECU model

Validated physico-

chemical model

Validated and

optimized ECU model




Calibration of fast-running ECU model from

physico-chemical model

• Soot mass in DPF is kept constant via

PI controller

• Inlet boundaries are varied from case to

case to find the characteristics of the DPF

• Passive and active regeneration can be

investigated & calibrated

Model-based calibration of the

DPF soot burn functionality

PI controller

• Inlet concentrations

• Exhaust gas mass flow

• Exhaust gas temperature

• Outlet concentrations

• Soot mass in DPF

dmSoot,DPFus mSoot,DPF

DPF

model

Target DPF

soot mass



• DPF soot load measured in various load cycles

• Predictions of engine ECU show good fit with measured soot load

for different cycles

• Multiple soot regeneration strategies are evaluated in real cycles

• Active regeneration was achieved by late post injection

• ECU soot burn model is able to describe burned soot mass

precisely

Evaluation of DPF soot model in multiple real field cyclesDP

F s

oot

mass [

g]

0

20

40

60

80

100

Time [s]

0 600 1200 1800 2400 3000 3600 4200 4800

Calculated soot mass by ECU Measurement

Tem

pera

ture

[°C

]

0

150

300

450

600

750 Exhaust gas Temperature after DPF

PM

[g]

0

20

40

60

80

100

Time [h]

0 20 40 60 80 100 120 140 160 180

WHTC ECU WHTC Low Load Driving Cycle 1 ECU Low Load Driving Cycle 1 Low Load Driving Cycle 2 ECU Low Load Driving Cycle 2

Agenda







Summary and conclusion

• Diversity in applications and therefore in load collectives in HD applications

• The holistic engine and EAT optimization approach is introduced and evaluated by IAV

• Main targets of holistic system evaluation are:

Engine emission concept development and EAT design optimization

Testing comb. system and EAT concept and calibration under real field cycles

Evaluation of RDE conformity problems in critical customer cycles

• Series calibration tasks can be supported with physico-chemical modelling in GT Suite

Holistic engine and EAT system optimization for virtual concept development, ensuring PEMS

conformity, preventing field issues in real field cycles!


Contact

M. Sc. Martin Weber

Advanced Engineering & Model Based Development

Commercial Vehicle Powertrain

IAV GmbH

Nordhoffstraße 5, 38518 Gifhorn (Germany)

[email protected]

www.iav.com

Series calibration supportHigh altitude engine calibration

Validation setup at IAV test bench with altitude simulator (Altitudes up to 4000m possible)


Pressure downstream turbine is

controlled with a compressor

EGR-cooler

intercooler

turbine

compressor

air filter

Pressure upstream compressor

is controlled with a throttle valve

engine

Tu

rbo

ch

arg

er

Sp

ee

d [

10

00

/min

]

80

90

100

110

120

130

140

En

gin

e o

ut

tem

pe

ratu

re [

K]

650

700

750

800

850

900

950

Operation Point

1 2 3 4 5 6 7 8 9 10

measured values simulated values 50 m

To

rqu

e [

Nm

]

Engine Speed [rpm]

1000 1500 2000 2500 3000

4

7

10

3

6

9

2

5

8

1

Series calibration supportHigh altitude engine calibration

Model was calibrated only

for height of 50 m

No further calibration with

high altitude conditions

Simulation shows good match with test bench data


Tu

rbo

ch

arg

er

Sp

ee

d [

10

00

/min

]

80

90

100

110

120

130

140

En

gin

e o

ut

tem

pe

ratu

re [

K]

650

700

750

800

850

900

950

Operation Point

1 2 3 4 5 6 7 8 9 10

measured values simulated values 50 m 2000 m

Tu

rbo

ch

arg

er

Sp

ee

d [

10

00

/min

]

80

90

100

110

120

130

140

En

gin

e o

ut

tem

pe

ratu

re [

K]

650

700

750

800

850

900

950

Operation Point

1 2 3 4 5 6 7 8 9 10

measured values simulated values 50 m 2000 m 3500 m

Full Load 90% Load 75% Load

Innovative raw emission modeling approach


IAV tabulated NOx

kinetics show

improved accuracy

compared to Zeldovich

NO

x [

ppm

]

Case [-]

1 2 3 4 5 6 7 8 9

Measured Simulated with the DI-Pulse combustion model,

using the tabulated NOx kinteics Simulated with the DI-Pulse combustion model,

using the Zeldovich mechanism

Torq

ue [

Nm

]E

ngin

e s

peed [

1/m

in]

Engine speed Torque

400

300

Me

an

effe

ctive

pre

ssu

re [b

ar]

Engine speed [1/min]

600 900 1200 1500 1800 2100

OP4

OP5

OP6

OP1

OP2

OP3

OP7

OP8

OP9Phenomenological

Modeling

Physics based

Data-driven

Modeling

Empirical (DoE)

NOx

Soot

HC

CO

• For most applications, a

phenomenological NOx

model can be calibrated to

a good fit

• The formation of other

pollutants is highly

dependent on 3D in-

cylinder processes

Much harder to model

• Empirical models can

improve the prediction of

other pollutants

123

4

5

6

7

8

9

1011

12

13

14

15

16

17

18

19

2021

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

6263

64

65

66

67

68

69

qin

j [m

g]

Engine speed [1/min]

Soot [F

SN

]

Case [-]

0 10 20 30 40 50 60 70

Measured class. Model

0.1 FSN

Soot [F

SN

]

Case [-]

0 10 20 30 40 50 60 70

Measured class. Model hybr. Model

0.1 FSN

Innovative raw emission modeling approach

• Validation of models based on different operating points

• Emission models were not trained with the validation points below

Hybrid emission modeling approach is investigated in the IAV internal research activity

“Classical”

DoE

emission

model

Hybrid

emission

model

(GT + DoE)

nEng

mFuel

λExhaust

SOImain

TCyl,max

…

λExhaust

EGR + res. gas

COHR

TCyl,max

Ignition delay

Burn duration

…


holistic engine and eat system simulation from concept to ......throttle and combustion calibration...

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