Simulation of DPF regeneration strategies · Simulation of DPF regeneration strategies GT-SUITE U C fSUITE Users Conference Frankfurt a. M., 20.10.2008 0 8 y right Liebherr 20 Cop

Simulation of DPF regeneration strategies

GT SUITE U C fGT-SUITE Users Conference

Frankfurt a. M., 20.10.2008

08yr

ight

Lie

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LMBA. Schilling,

Dr. R. Röthlisberger20.10.2008

Content

IntroductionGT-Power simulation conditionsSimulation-based study of regeneration strategiesResults Conclusions and outlook

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2 DPF regeneration

Content


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3 DPF regeneration

Introduction: DPF regeneration strategies overview

DPF regeneration

activepassive

t l t engine thermomanagement

additional fuel injection

catalyst

fuel additive

08

cylinder

exhaust

NO2-based

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iebh

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00

burner

catalytic combustion

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4 DPF regeneration

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Introduction: Target conditions for regeneration

Temperature before DOC

Temperature before DPFp

Oxygen concentration

turb

HC doser

08

DOC DPF

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TbDOC > 350 °CEnough O2 (6-8%)

TbDPF > 650 °CEnough O2

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5 DPF regeneration

for soot oxidation

Content


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6 DPF regeneration

Engine considered

Name: D9508

Cylinder: V8

Power: 500 kW

Emission level: 3B

EGR system: external

Turbocharging: 2 stages, waste-gate

08

g

Injection: direct, common-rail

DPF AC 200/12

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ht L

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00DPF: AC 200/12, 15’’ x 16’’

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7 DPF regeneration

DOC + DPF modeling with GT-Power

Equivalent modeling, since details of the DOC chemistry not known

press loss

DOC DPF

pressloss

press loss+

temp increaseturbDOC DPF

=

08

=turb

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ht L

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00

DOC DPFburner

pressloss

temp increase

pressloss

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8 DPF regeneration

lossincreaseloss

DOC + DPF modeling with GT-Power

Pressure drop calibration results

DOC i fl DPF i i i

16

meas smallsim small

140

meas cleansim clean

DOC, various mass flows, comparison of two sizes

DPF, various sizes, comparison between clean and loaded

10

12

14

[mba

r]

meas bigsim big

100

120

[mba

r]

sim cleanmeas loadedsim loaded

08

6

8

10

pres

sure

dro

p

60

80

pres

sure

dro

p

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ht L

iebh

err 2

00

1000 1200 1400 1600 1800 2000 2200 24002

4

exhaust gas mass flow [kg/h]

7.5x12 9x12 10.5x12 12x13 15x15 13x15 13x1720

40

DPF size [in x in]

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9 DPF regeneration

exhaust gas mass flow [kg/h] DPF size [in x in]

GT-Power simulation conditions

5 operating points

4 piping lengths

With and without isolation

DPF loaded with 3 g/l soot

load [%]

100

L = 1 – 4m

08

100

50

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[rpm]10

1000 20001500

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10 DPF regeneration

1000 20001500

Content


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11 DPF regeneration

Characterization of the engine operation

600]

Piping length 1m vs. 4m Effect on temperature before DOC

450500550

. DO

C [°

C]

clean - 1m

300350400450

ratu

re b

ef.

clean - 4mloaded - 1mloaded - 4m

08

200250300

Tem

pe

yrig

ht L

iebh

err 2

0010% 10% 50% 100% 100%

1000rpm

2000rpm

1500rpm

1000rpm

2000rpm

Thermomanagement needed

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12 DPF regeneration

p p p p p

Engine control configuration

HCIM LC

THR

EGR

THR

EGR ctrl HC ctrlλ TbDPF

HC

08

LTHTEM DOC

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00WG

TbDOCWG+THR ctrl

DPF

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13 DPF regeneration

Example: Thermoman. + HC dosing at 2000 rpm, 10%

05

1015

WG

[mm

]

Opening of the WG

0W6090

R [m

m]

Coordinate30TH

R

20[mm

]Coordinate control of EGR valve and THR to achieve

t l t t

08

10EGR

[

11.5

s]

control targets

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0 3 6 9 12 150

0.51

time [s]

HC

[g/s

HC dosing

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14 DPF regeneration

time [s]

Example: Thermoman. + HC dosing at 2000 rpm, 10%

300

400

OC [°

C]

200T bDO

1

2

3

λ [-]

08

1

600[°C

]

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0 3 6 9 12 15200

400

ti [ ]

T bDPF

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15 DPF regeneration

time [s]

Content


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16 DPF regeneration

Exhaust piping isolation

Question: Need for exhaust piping isolation?

Answer: Test thermoman., variation of piping length 1m 4m

500

550

OC

[°C

]

, p p g g

Isolation needed for L > 1m

400

450

re b

ef. D

O 1m2m3m

08250

300

350

Tem

pera

tu 4m

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err 2

0025010% 10% 50% 100% 100%

1000 rpm 2000 rpm 1500 rpm 1000 rpm 2000 rpm

T

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17 DPF regeneration


Question: Isolation thickness?

Answer: Test thermoman., piping length = 4m, increasing , p p g g , gisolation thickness

Temp before DOC [°C]

350400450500550600

bef

. DO

C [°

C]

100120140

DO

C [K

]

no isol

p [ ]Temp loss TC-DOC [K]

08

250300350

10% 10% 50% 100% 100%

1000 2000 1500 1000 2000

Tem

p.

020406080

100

mp.

loss

TC

-D no isolisol 10mmisol 20mmisol 30mm

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00rpm rpm rpm rpm rpm 010% 10% 50% 100% 100%

1000rpm

2000rpm

1500rpm

1000rpm

2000rpm

Te

No more improvements by thickness > 20 mm

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18 DPF regeneration

by thickness > 20 mm

Feedback of HC dosing on thermomanagement

Question: Feedback of HC dosing?

Answer: Increased backpressure due to higher mass flowp g

200

250

[mba

r]

100

150

200

e be

f. D

OC

thermoman.+ HC dosing

08

50

100

l. pr

essu

re

thermoman.

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ht L

iebh

err 2

00

010% 10% 50% 100% 100%


Re

(Example: L = 1m,

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19 DPF regeneration

1000 rpm 2000 rpm 1500 rpm 1000 rpm 2000 rpmno isol.)

Oxygen concentration analysis

9101112

ntra

tion

[%]

6789

gen

conc

en

45

10% 10% 50% 100% 100%

Oxy

g

08

1000 rpm 2000 rpm 1500 rpm 1000 rpm 2000 rpm21% (air)

HC dosinginjection (Example: L = 1m, isol )

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Engine DOC +burner DPF

isol.)

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20 DPF regeneration

burner

Fuel consumption variation during DPF regeneration

45

Question: Fuel consumption increase during regeneration?

30354045

aria

tion

[%

cyl - 1m

thermoman. + HC dosing

10152025

sum

ptio

n va cyl - 1m

cyl - 4mcyl+HC - 1mcyl+HC - 4m

thermoman.

08-505

10

Fuel

con

s y

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00510% 10% 50% 100% 100%

1000rpm

2000rpm

1500rpm

1000rpm

2000rpm

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21 DPF regeneration

p p p p p

Total fuel consumption optimization

Question: Is there an optimal strategy for fuel injection splitting between engine and HC doser to achieve the target temperature b f DPF?before DPF?

standarddecreasing engine efficiency

HC dosinginjection

08

engine DOC +burner DPF

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lower temphigher temp

target temp

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22 DPF regeneration

higher temp


Answer: Investigation of the effects of WG opening and THR closing (thermoman. not necessary at these 2 operating points)

50

1500rpm 50%2000rpm 100% 0

1500rpm 50%2000 100%

Variation of temp before DOC [K] Variation of total fuel cons [%]

30

40

[K]

2000rpm 100%

-0.5

0

%]

2000rpm 100%

0810

20

30

ΔTbD

OC [

-1.5

-1

Δfue

l tot [%close THR

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ht L

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100 90 80 70 60 50

0

10

THR di [ ]

100 90 80 70 60 50

-2

open WG

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23 DPF regeneration

THR diameter [mm]100 90 80 70 60 50

THR diameter [mm](Example: L = 1m, no isol.)


Answer: Investigation of the effects of shifting combustion to late

Could be a possibility to reduce NOx during regeneration!

40

1500rpm 50%12

1500rpm 50%

p y g g

Variation of temp before DOC [K] Variation of total fuel cons [%]

25

30

35

K]

2000rpm 100%

8

10

%]

2000rpm 100%

0810

15

20

ΔTbD

OC [K

4

6

Δfue

l tot [%

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ht L

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0 2 4 6 8 100

5

10

0 2 4 6 8 100

2

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24 DPF regeneration

0 2 4 6 8 10shift comb [CA°]

0 2 4 6 8 10shift comb [CA°](Example: L = 1m, no isol.)

Content


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25 DPF regeneration

Overview thermomanagement

Engine load[%]

controllable, TbDOC100λ

TbDOC

λ

needs to be controlled

not controllable

50TbDOC

λ

doesn’t need to be controlled

08TbDOC TbDOC

λ

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Engine speed[rpm]1000 1500 2000

10bDOC

λbDOC

λ

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26 DPF regeneration

[rpm]

Overview thermomanagement

Engine load[%]

WG WGopen

WG100 THR

EGR

WGTHREGR

closed

controlled

50WGTHR

08

WGTHR

WGTHR

EGR

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Engine speed[rpm]1000 1500 2000

10 EGR EGR

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27 DPF regeneration

[rpm]

Conclusions

Thermomanagement: Needed at low load

Isolation:

Needed for exhaust piping length > 1m

No more improvements by thickness > 20mmNo more improvements by thickness 20mm

Almost same total consumption for all piping lengths 1m - 4m

1000 rpm 10% most critical: At L = 4m temp-bef-DOC > 350 °C

08

1000 rpm 10% most critical: At L 4m temp bef DOC > 350 C obtained only with isolation and with very small margin

Optimal fuel injection splitting: As less fuel as possible in the li d h d d i th HC d

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ht L

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00cylinders, as much as needed in the HC doser

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28 DPF regeneration

Outlook

Simulation of post injection and late-post injection Injection system model and predictive combustion model needed

Effect on NOx Predictive combustion model needed

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29 DPF regeneration

Thank you for your attention! Do you have questions?

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LMBA. Schilling,

Dr. R. Röthlisberger20.10.2008

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31 DPF regeneration

Simulated engine system configuration

HCIM LCTHR

post INJ

EGR

HC

retard

08

LTHTEMretard

SOIISOL

DOC

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ht L

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err 2

00WGthermomanagement

optional

DPF

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32 DPF regeneration

optional

Thermomanagement + HC dosing: Control strategy

N NTbDOC =target?

WG wide open?

Y

N

Y

NWG ctrl

THR ctrlλ =

target?N

EGR ctrl

08

Y

N

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Y

NTbDPF =target?

HC ctrl

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33 DPF regeneration

Content

IntroductionModeling of the aftertreatment systemg yGT-Power simulation conditionsSimulation-based study of regeneration strategiesResults Conclusions and outlook

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34 DPF regeneration

Characterization of the engine operation

180ar]

Clean vs. loaded DPF Effect on backpressure

120140160

DO

C [m

ba

clean - 1m

6080

100

ssur

e be

f. clean - 4mloaded - 1mloaded - 4m

08

02040

Rel

. pre

s

yrig

ht L

iebh

err 2

0010% 10% 50% 100% 100%

1000rpm

2000rpm

1500rpm

1000rpm

2000rpm

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35 DPF regeneration

p p p p p

Plant input/output characterization

INJG1

INJG2

uINJ ME

λEGRG1

HCG3

uEGR

EGRG2

THRG2

08

EGR2

THRG1 TbDOCuTHR

INJG3

yrig

ht L

iebh

err 2

00

HCG2

HCG1uHC TbDPF

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36 DPF regeneration

HCG1HC bDPF

Example: Plant uTHR TbDOC for piping length 1m to 4m

50

100

ottle

eter

[mm

]

0thro

diam

e

100

0

50

ΔT [K

]

1000 rpm, 10% L ↑

08150

300

[K]

2000 rpm 10%L ↑

yrig

ht L

iebh

err 2

00

0 0.5 1 1.5 2 2.5 3 3.5 40

150

time [s]

ΔT [2000 rpm, 10%

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37 DPF regeneration

time [s]


Question: Influence of isolation on total fuel consumption?

Answer: Test at piping length = 1m (isolation not absolutely

1

n [%

p p g g ( ynecessary at this piping length)

Not same λ!

0 5

0

0.5

tion

varia

tio

08

-1.5

-1

-0.5

l con

sum

pt

yrig

ht L

iebh

err 2

00

-210% 10% 50% 100% 100%


Fue

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38 DPF regeneration


Simulation of DPF regeneration strategies · Simulation of DPF regeneration strategies GT-SUITE U C fSUITE Users Conference Frankfurt a. M., 20.10.2008 0 8 y right Liebherr 20 Cop

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