urea scr and dpf system for diesel sport utility vehicle

1

DEER Conference – August 2003

Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting

Tier II Bin 5DOE and Ford Motor Company Advanced CIDI

Emission Control System Development Program(DE-FC26-01NT41103)

Diesel Engine Emission Reduction ConferenceAugust 2003

2


Presentation Overview

• DOE Program Overview• Vehicle Results• SCR Functional Improvements• Exhaust Gas Sensor Development• CDPF Strategy Development• Urea Program• Future Work

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Tier II Bin 5

Program Overview

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Phase I - Initial build/test phase (12 mos.)Establish baseline emission control systemDeliver engine dynamometer NOx and PM test resultsDemonstrate and deliver prototype vehicle NOx and PM test resultsDeliver urea delivery (infrastructure) prototype

Phase II - System/component optimization phase (18 mos.)Define final system hardware componentsDeliver NOx and PM performance dataDemonstrate emission control system (includes NOx and PM data)

Phase III - Durability/Demonstration phase (18 mos.)Definition of durability test procedureFinal NOx and PM emission levels Define fuel sulfur limits for emission control systemFinal report for the completed program

DOE Ultra-Clean Fuels ProgramOutline of Ford’s program to achieve Tier II emissionstandards for 2007 using low sulfur diesel fuel as an enabler for a high efficiency aftertreatment system.

Primary Contractor

Subcontractors

Catalyst Suppliers

5


FEV ProgramConcept Design• CFD Modeling including urea injection

Engine Dynamometer• Baseline and rapid warm-up testing• Urea SCR/CDPF optimization• Transient FTP/US06 testing

Emission Control System Durability• 5000 hours (~120k miles)

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ExxonMobil ProgramIntellectual property discussion delayed program for 9 months; program was then accelerated to contain original objectives.

SCR urea catalyst development• Durable, high NOx conversion from 150° to

600°C with low N2O make.Urea program• Co-fueling concept• Low temperature urea solution• Infrastructure studiesFuel development• Make and use fuel, which will be typical of 2007

production with 15 ppm sulfur cap.

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Tier II Bin 5

Vehicle Results

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aqueousurea

DOC

Turbo

NOx sensor

Spray Deflector

Flow mixing plate

SCRCatalyst

DOC

LDT Exhaust System

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Diesel Fuel Properties• ExxonMobil blended 14,000 gallon batch to represent

typical 2007 ULSD.– Uniform fuel over program duration.– Stored and dispatched in drums.

Estimated Proposed Program Proposed‘06 Diesel DOE Program Fuel 2007

Fuel Property Properties Min/Max Delivered Cert. FuelSulfur, ppm 15* 10 / 15 12.5 7 / 15Density, kg/m3 850 820 / 850 841.1 839 / 865Aromatics, vol. % 32 25 / 32 29.5 27 minPolyaromatics, wt. % 10 6 / 11 11.0 no specCetane number 46 44 / 48 44.9 40 / 50T50, C 267 250 / 280 249 243 / 282T90, C 306 300 / 320 307 293 / 332

* As delivered to the vehicle

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LDT Temperatures and Space VelocityFTP-75 Test

0

50

100

150

200

250

300

350

400

0 500 1000 1500 2000

Time (seconds)

Tem

pera

ture

(°C

)

0

20000

40000

60000

80000

100000

120000

140000

160000

Spac

e Ve

loci

ty (h

r-1)

Turbo Out DOC in SCR in SCR out Space Velocity

urea on

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Weighted FTP-75 Emissions

0.0060.004

0.107(52%)

0.082(52%)

0.0320.041(82%)

0.033(94%)

0.015 (97%)

0.067(79%)

0.007 (96%)

0.00

0.05

0.10

0.15

0.20

0.25

THC NMHC CO/10 NOx

gram

s/m

ileBag 3 emissionsBag 2 emissionsBag 1 emissions

Tier II Bin 5Stds, 120k mi

( ) Catalyst efficiency

0.062 (93%)

0.208 (82%)

0.088 (82%)

0.042

0.42

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Tier II Bin 5

SCR Functional Improvements

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Importance of NO2/NOx Ratio on Degreened Catalyst Performance

0

10

20

30

40

50

60

70

80

90

100

150 200 250 300 350 400 450 500 550 600

Catalyst Temperature (°C)

NO

x C

onve

rsio

n (%

)

NO only1:1 NO:NO2

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Importance of NO2/NOx Ratio on Aged Catalyst Performance

0

10

20

30

40

50

60

70

80

90

100

150 200 250 300 350 400 450 500 550 600

Catalyst Temperature (°C)

NO

x C

onve

rsio

n (%

)

HT aged, NO only

HT aged, 1:1 NO:NO2

sulfated, NO only

sulfated, 1:1 NO:NO2

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Impact of Sulfur and Regeneration on SCR Performance

0

10

20

30

40

50

60

70

80

90

100

150 200 250 300 350 400 450 500 550 600 650Catalyst Temperature (°C)

NO

x co

nver

sion

(%)

degreened

120k mi sulfated

after regen at 650°C

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0

10

20

30

40

50

60

70

80

90

100

NO

x C

onve

rsio

n (%

)

0

2

4

6

8

10

12

14

16

18

20

Cum

ulat

ive

HC

s (g

/l ca

taly

st)

% NOx Conv.Cum. HC's

Impact of HC on SCR performance

DegreenedActivity(250°C,

20% NO2in feed)

Start HCAddition

500°C,10 min

ActivityRegained

End HCAddition

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Importance of Urea Mixing(Steady-State Engine Dyno Results)

0

10

20

30

40

50

60

70

80

90

100

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

NH3 / NOx Ratio [molar]

NO

x C

onve

rsio

n [%

]

0

10

20

30

40

50

60

70

80

90

100

NH

3 Sl

ip /

Engi

ne O

ut N

Ox

[%]

target 25 mm

target 150 mm

mesh downstream

mesh upstream

target 25 mm slip

target 150 mm slip

mesh downstream slip

mesh upstream slip

System A conv

System B conv

System C convSystem D convSystem A slip

System B slip

System C slipSystem D slip

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Importance of Urea Mixing(Transient Vehicle Results)

0

10

20

30

40

50

60

70

80

90

100

0 250 500 750 1000 1250 1500 1750 2000test time (s)

Cum

ulat

ive

TP N

Ox

(% E

O N

Ox)

Poor mixingImproved mixing

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Importance of Rapid Warmup

0

5

10

15

20

25

30

0 250 500 750 1000 1250 1500test time (s)

Cum

ulat

ive

TP N

Ox

(% E

O N

Ox)

ModelModel w/rapid warmup

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Tier II Bin 5

Exhaust Gas Sensor Development

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S(NO) > S(NH3) > S(NO2)

sensitivity

C3H6 (ppm)0 200 400 600 800 1000 1200

V

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

100 ppm NO

baseline

100 ppm NO2

100 ppm NH3

(~1cm DIA tube)

NOx sensor (NGK):• Laboratory data: • Vehicle data:

• For this test, the sensor was located downstream of SCR catalyst. As expected, the sensor responded to both NO and NH3. Also, the tailpipe NOx was all NO.

time (sec))0 200 400 600 800 1000 1200

ppm

0

100

200

300

400

500

600

NO (FTIR)NO2 (FTIR)NH3 (FTIR)Sensor (ppm_NO)

2_06_03: 112:bags1_2

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Vehicle test: Comparison of NH3 measured at the tailpipe using FTIR with

that predicted by the sensor (after

compensating for water)

NH3 Sensor:• Prototype sensors are under development by automotive

suppliers.• Vehicle data from one such sensor shown below (composition

proprietary) :– Selective NH3 response. Some sensitivity to H2O.

time (sec))0 200 400 600 800 1000 1200 1400

ppm

-20

0

20

40

60

80

100

120

140

FTIRsensor

6_03_03: 561:bags1_2

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Tier II Bin 5

CDPF Strategy Development

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Future LDT Exhaust System

aqueousurea

DOC

Turbo

NOx sensor

Spray Deflector

Flow mixing plate

SCRCatalyst

DOC

aqueousurea

DOC

Turbo

NOx sensor

Spray Deflector

Flow mixing plate

SCRCatalyst

DOC

CDPF

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Temperatures during DPF Regeneration

2

34

5

6

7

8

9

1

9” dia x 10” L(229 x 254 mm)

L from rearof filter grid

T# (mm) type1 175 complete2 125 complete3 50 complete4 175 cent. side5 125 cent. side6 50 cent. side7 175 corner8 125 corner9 50 corner

0 5 10 15 20 25 30 35 40 45 50 55200

300

400

500

600

700

800

900

Exha

ust T

empe

ratu

re [°

C]

Time [min]

TBDPF TDPF6 TDPF1 TDPF7 TDPF2 TDPF8 TDPF3 TDPF9 TDPF4 TADPF TDPF5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

Fue

l Flo

w [k

g/h]

Fuel Flow

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Temperatures during DPF Regeneration

0 2 4 6 8 10 12 14 16200

300

400

500

600

700

800

900

Exh

aust

Tem

pera

ture

[°C

]

Time [min]

T_BDPF T_DPF1 T_DPF2 T_DPF3 T_DPF4 T_DPF5 T_DPF6 T_DPF7 T_DPF8 T_DPF9 T_ADPF

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

Fuel

Flo

w [k

g/h]

Fuel Flow

2

34

5

6

7

8

9

1

9” dia x 10” L(229 x 254 mm)

L from rearof filter grid

T# (mm) type1 175 complete2 125 complete3 50 complete4 175 cent. side5 125 cent. side6 50 cent. side7 175 corner8 125 corner9 50 corner

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Tier II Bin 5

Urea Program

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Urea ProgramPrototype Urea Co-fueling System Status• Co-axial nozzle design chosen and

improved for durability and reliability. • Urea pumping unit designed and

feasible for modern dispenser.• Prototype system being built to

evaluate co-fueling, including low temp.• Vehicle modified with compatible fill-

neck and urea storage for demo.

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Urea ProgramLow Temperature Urea Solution

• Use of aqueous urea can cause difficulty in cold climates.

• Urea at 32.5 wt% has the lowest freeze point at 12°F(-11°C) of any blend in water.

• Potential freeze point depressants investigated, but found to cause negative catalyst impact at Ford.

Conclusion: Heated systems will be needed for colder climates.

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Urea ProgramStudy of Urea Supply Scenario

• Meeting with key urea suppliers to understand supply chain from production to service station.

• Using A. D. Little Study as baseline. • Determining optimum supply case.

- forecast urea volumes- estimate urea cost per gallon

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Tier II Bin 5

Future Work

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Future Work

• Rapid warm-up strategy• Choose final catalyst formulations/configuration• Aging cycle development – 5000 hrs• Sensor development• Continue urea infrastructure investigation

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Acknowledgements

FordBrendan Carberry, Dick Chase, Bob Hammerle, Dave Kubinski,Paul Laing, Christine Lambert, Mike Levin, Cliff Montreuil,Rick Soltis, Devesh Upadhyay, Michiel van Nieuwstadt,Scott Williams

FEVErik Koehler, Dean Tomazic

Exxon MobilJoan Axelrod, Jeff Beck, Bill Blazowski, Owen Feeley, Rich Grosser, Mike Kerby, Marcus Moore, Mike Noorman, Charlie Schleyer

urea scr and dpf system for diesel sport utility vehicle

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