Oct 4, 2011 1

Development of the 2011MY Ford Super Duty Diesel Catalyst System

Christine Lambert, Giovanni Cavataio and Douglas Dobson Ford Research and Advanced Engineering, Dearborn, MI

2011 DEER Conference

Oct 4, 2011 2

Outline

• Background of Ultra-Clean Fuels Program • Tech Selection for 2010 Emissions • Development Challenges with SCR • Diesel MDV Impact on Sustainability • Next Steps • Conclusions & Acknowledgements

Oct 4, 2011 3

DOE Ultra-Clean Fuels Program

Phase I - Initial build/test phase (July 01-July 02) Establish baseline emission control system Deliver engine dynamometer NOx and PM test results Deliver prototype vehicle NOx and PM test results Deliver urea delivery (infrastructure) prototype Phase II - System/component optimization phase (July 02-July 04) Define final system hardware components Deliver NOx and PM performance data from fresh system Phase III - Durability phase (July 04-Dec 05) Definition of durability test procedure Final NOx and PM emission levels Final report for the completed program

Outline of Ford’s program to achieve Tier 2 FTP emission standards for 2007 using ultra low sulfur diesel (ULSD) as a key

enabler for a high efficiency aftertreatment system. Primary Contractor

Subcontractors

Catalyst Suppliers

DEER 2004

Oct 4, 2011 4

Diesel NOx Control Options

Based on the above data, urea SCR was chosen as the prime option for Ford’s UCF Program.

Estimated fuel penalties of

for the LD FTP-75 Typical performance curves for

slightly aged catalysts

SAE 2004-01-1292

Oct 4, 2011 5

Background of UCF Program LDT Exhaust System

urea

DOC

NOx sensor

SCR

DOCDOC

CDPF

Spray Target

to engine intake

• Engine-out NOx lowered by 40% with increased EGR• Low tailpipe NOx achieved with rapid warm-up strategy

• lower thermal mass upstream of catalyst system• engine calibration changes during cold start (post injection & inc. idle speed)

>90% FTP NOx conversion, 0.05 g/mi TP NOx

exhaustflow

Diesel Fuel Properties

• ExxonMobil blended 14,000 gallon batch to represent typical 2007 ULSD

Est. Avg. 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

• Diesel fuel specially blended at <15 ppm-wt Sulfur • 6000 lbs LDDT used as a demonstrator of aged aftertreatment • Catalysts aged on engine dynamometer for 120K mi equivalent • Objective was Tier 2 Bin 5 (120k mi): 0.07 g/mi NOx, 0.01 g/mi PM

DEER 2006

SCR Catalyst Options

Oct 4, 2011 6

0

10

20

30

40

50

60

70

80

90

100

100 150 200 250 300 350 400 450 500 550 600 650

Inlet Gas Temperature (ºC)

Gro

ss N

Ox

conv

ersi

on (%

)

Cu-Based SCR

Fe- Based SCR

Vanadium Based SCR

FTP US06

• Cu/zeolites are best at low temperatures

• Fe/zeolites perform well at high temperatures

• Vanadium based SCRs are not appropriate for US Diesels with Filters

SAE 2007-01-1575

Oct 4, 2011 7

Key Accomplishments of Ford’s UCF Program

• >80% NOx reduction was achieved on a 6000 lbs light-duty diesel truck • Tailpipe NOx was below the T2B8 emission standard (0.2 g/mi NOx) • Proved Cu/zeolite had sufficient durability to withstand filter regens

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Tailp

ipe

NO

x (g

/mi)

Increase due to loss of postinjection control

4K 4K 50K 120K

4KDOC, 120KSCR

Aging Summary: FTP-75 Weighted NOx

• Loss of DOC activity resulted in higher NOx emissions at 120k mi

Improvement withfresh DOC

34

Durability Test Definition

0

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30

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60

70

80

90

0 250 500 750 1000 1250 1500time (s)

vehi

cle

spee

d (m

ph)

Ford High Speed Cycle (HSC)

• average speed = 47 mph

• max speed = 75 mph

DEER 2006

Bin 5

Oct 4, 2011 8

Key Accomplishments (con’t)

• Urea mixing in the exhaust found to be critical for high NOx conversion

• Developed urea/diesel cofueling dispenser • Predicted long term bottled urea cost of $3.66/gal • Long term cofueled urea price ~$1.50/gal

0

10

20

30

40

50

60

70

80

90

100

150 250 350 450 550 650

Catalyst Temperature (°C)

NO

x C

onve

rsio

n (%

)

HC SCRLNT

Urea SCR

Oct 4, 2011 9

Aftertreatment Selection for 2010 Super Duty

• Ba LNT determined not capable for eng dyno cert • K LNT had durability issues, large size, high cost • Decision was made to certify 90% of diesel MDV fleet volume as complete chassis on

FTP-75 (LEVII F250/F350 - Class 2b 8,501-10,000 lbs and Class 3 10,001-14,000 lbs) • Desire to align chassis and dyno cert NOx control

Urea SCR became the prime option supported by data from Ford’s DOE program

FTP-75 Chassis Cert

HD Dyno Cert

Oct 4, 2011 10

Timeline for 2010 Super Duty Aftertreatment 7/01 Ford’s DOE Contract starts

4Q05 Urea SCR selected for 2010 Diesel

1Q05 Ford’s 2010 Diesel Program starts

3Q07 Diesel Catalyst RFQ to Suppliers

2Q06 Enhanced Cu/zeolite durability achieved

12/05 Ford’s DOE Contract ends

4/10 Super Duty J1

11/10 Super Duty J2

“Advanced” “Research” “Forward Model”

Ford research on SCR ~1990-2001

“not exactly to scale”

Parallel Research on SCR and LNTs

Oct 4, 2011 11

Diesel Aftertreatment Layouts

HC CO2

CO CO2 NO + NH3 N2

PM CO2NH3 N2HC,CO CO2

urea

DOC

NOxsensor

SCR

DOC*DOC*

CDPF

Spray Target

to engine intake

exhaustflow

HC CO2

CO CO2 NO + NH3 N2

PM CO2NH3 N2HC,CO CO2

urea

DOC

NOxsensor

SCR

DOC*DOC*

CDPF

Spray Target

to engine intake

exhaustflow

CDPF

Spray Target

to engine intake

exhaustflow

Spray Target

to engine intake

exhaustflowUCF Program Truck

6000 lbs LDDT • Pt DOC • Cu/beta SCR • Pt CDPF

2011MY Super Duty 8,500 – 14,000 lbs • Pd-rich DOC • Cu/CHA SCR • Pt/Pd CDPF

Cu/beta

Cu/CHA

Pt

Pd-rich

Pt

Pt/Pd

Oct 4, 2011 12

Temperature Operating Windows SCR Inlet Temperature on FTP-75

DOE truck with engine < 6.7L resulted in higher temperatures than production truck.

Temperature Comparison in FTP-75 Cycle

0

50

100

150

200

250

300

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400

450

0 200 400 600 800 1000 1200 1400 1600 1800

Test Time (s)

Tem

pera

ture

(C)

DOE truck (6000 lbs)

Ford 2011MY Super Duty (9500 lbs)

Vehicle Speed (mph)

Oct 4, 2011 13

Filter Regeneration Strategies

UCF program truck: • Downstream fuel injector • Long regen time studied • 80% regen in <10 min

2010 Super Duty: • Post injection in cylinder • Shorter regen times • Similar temperatures • Refined variables

6.7L Diesel Truck

0

100

200

300

400

500

600

700

800

900

6 7 8 9 10 11 12 13 14 15 16

Time (min.)

Tem

pera

ture

(C) a

nd D

PF L

oad

(mg/

L)

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1.6

1.7

DPF

Res

tric

tion

DPF InletDPF OutletDPF LoadDPF Restriction

0

100

200

300

400

500

600

700

800

5 15 25 35 45 55 65Time (min)

Tem

pera

ture

(C)

0

2

4

6

8

10

12

Pres

sure

(kPa

)

DPF InletDPF OutletDelta P - DPF

Oct 4, 2011 14

A Few Challenges Faced During Commercial Urea SCR System Development

• Thermal stability • Ammonia storage • Washcoat adhesion • HC poisoning/coking • Precious metal poisoning • Sulfur effects • Urea specifications and refill

Oct 4, 2011 15

Thermal Stability of DOC

0

0.2

0.4

0.6

0.8

1

100 150 200 250 300

Con

vers

ion

Effi

cien

cy

Temperature (Deg C)

HC Light-Off Conversion2-Mode 100 hrs / 300 ppm S + 20 mgP/gal

20:1

2:11:4

Pt only

0%

10%

20%

30%

40%

50%

150 200 250 300 350 400 450 500 550

% N

O2

of T

otal

NO

x

Temperature (C)

NO2:NOx

Pt only20:1

2:1

1:4

• Addition of Pd to Pt has a stabilizing effect for HC oxidation during cold-start

• Pd also stabilizes Pt for NO oxidation but has no inherent activity itself

Oct 4, 2011 16

Thermal Stability of SCR Catalyst

16

• Thermal stability of Cu/zeolite recently improved from 750 to 900 C (Cu/beta Cu/CHA)

• NO2 no longer needed for low temp conversion • Lower cost aftertreatment now possible

Cavataio 2008-01-1025

• With 20% NO2/NOx feed, the catalyst is durable to 750°C

0

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100

150 200 250 300 350 400 450 500 550 600

Temperature (°C)

NO

x C

onve

rsio

n (%

)

4k mi SCR catalyst20h 700°C40h 700°C20h 725°C20h 750°C20h 800°C

SCR Thermal Durability with 20% NO2/NOx FeedgasSCR Catalyst Durability: High Temperature

30K h-1

NO2/NOx = 0.2NH3/NOx = 1

DEER 2005

4NH3 + 4NO + O2 4N2 + 6H2O

Oct 4, 2011 17

Urea Dosing Strategy

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60

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90

100

0 100 200 300 400 500 600

Inlet Temperature, °C

% N

Ox

Con

vers

ion

Increasing NH3exposure

• SCR catalysts can store a large amount of ammonia

• A certain amount of ammonia on the catalyst surface is required for a given NOx conversion

• Data at different NH3 load are fed into the urea dosing strategy

DEER 2006

Oct 4, 2011 18

Washcoat Adhesion of DOC and SCR

dieselengine

aqueousurea

DOCPMfilter

dieselengine

aqueousurea

DOC SCRdieselenginedieselengine

aqueousurea

DOCPMfilter

aqueousurea

DOCPMfilter

dieselenginedieselengine

aqueousurea

DOC SCR

Main concerns for pre-filter catalysts: • Loose debris will create backpressure issues in the filter • Precious Metal loss to downstream components (primarily SCR) Result was DOC and SCR Washcoat Loss Targets one order of magnitude lower than for TWC coatings

Oct 4, 2011 19

HC Poisoning/Coking of Zeolitic SCR

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90

100

NO

x C

onve

rsio

n (%

)

0

2

4

6

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10

12

14

16

18

20

Cum

ulat

ive

HC

s (g

/l ca

taly

st)

% NOx Conv.Cum. HC's

DegreenedActivity(250°C,

20% NO2in feed)

Start HCAddition

500°C,10 min

ActivityRegained

End HCAddition

SCR Catalyst Durability: HC

• HC poisoning is reversible after 500°C, lean

HC Inhibition HC Storage/Exotherm

Both issues were resolved by transition from Cu and Fe/beta to Cu/CHA DEER 2004

Oct 4, 2011 20

Sulfur Effects on Cu/zeolite

0

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60

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150 200 250 300 350 400 450 500 550 600 650

Catalyst Temperature (°C)

NO

x co

nver

sion

(%)

degreened

120k mi sulfated

after regen at 650°C

• Sulfur affects NOx activity below 300C • Sulfur can be removed by lean filter regeneration conditions (>650C) • Amount adsorbed between regens can be tolerated based on 15 ppm-

wt S in diesel fuel

Effect of 20ppm SO2 at 200°C(Calculated miles based on 15ppm fuel sulfur)

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Temperature(°C)%

NO

x C

onve

rsio

n

0 miles

500miles

Effect of 120K mi at 15ppm fuel sulfur

DEER 2004

Oct 4, 2011 21

Precious Metal Poisoning of SCR

SAE 2008-01-2488 SAE 2009-01-0627

• Pt from upstream DOC can volatilize and interfere with SCR function • Prime indicators are increased NH3 oxidation and N2O make • Front section of catalyst most affected and can be regenerated • Pt DOC may be stabilized with addition of Pd and lower exotherm Ts

EVALUATION of DYNAMOMETER AGED FeSCR CATALYST

Lab flow reactor Pt poisoning of Cu SCR by upstream DOC

-50

-25

0

25

50

75

100

100 150 200 250 300 350 400 450 500 550 600

Inlet Gas Temperature (ºC)

NO

x C

onve

rsio

n (%

)

Non - ContaminatedContaminated

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100

100 150 200 250 300 350 400 450 500 550 600Catalyst Temperature (ºC)

NO

x C

onve

rsio

n (%

)

1st Inch (Inlet)2nd Inch3rd Inch4th Inch5th Inch6th Inch (Outlet)

Oct 4, 2011 22

Potential Biodiesel Effects

• ASTM D6751-08 limits Group I metals (Na+K) < 5 mg/kg for biodiesel component • The actual deposit amount on the catalysts will depend on the capture efficiency • Real-world biodiesel may have much lower Na & K than the spec

0

1

2

3

4

5

0 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000Mileage

Na

or K

Exp

osur

e (w

t%)

SCR

DOC

Potential weight percentage exposure rate of Na/K over a typical DOC and SCR as a

function vehicle mileage. (B100)

-40

-20

0

20

40

60

80

100

100 200 300 400 500 600 700

Inlet Gas Temperature (ºC)

NO

x C

onve

rsio

n (%

)

0.00% K

0.10% K

0.25% K

0.50% K

0.70% K

1.00% K

3.00% K

Cu-SCR#1 NOx activity impact for NO+NH3 as a function of LAB DOPED K contamination level.

SAE 2009-01-2823

Oct 4, 2011 23

Urea Specifications and Refill

• OEMs and suppliers formed USCAR working group to define specifications

• Aqueous urea is sold as “Diesel Exhaust Fluid” or “DEF”

• Current refill uses bottles, drums, totes, and bulk dispensers

• ~ $2.79/gal in bulk • ~ $4.65/gal in bottles http://www.dieselexhaustfluid.com/ Mattina, 16th Annual Fleet Fueling Conference, Sept

2010.

• Websites offer DEF locations

http://www.factsaboutscr.com

Oct 4, 2011 24

Diesel MDV Impact on Sustainability

Year1995 2000 2005 2010 2015

CO

2 (g/

kWh)

at P

eak

Torq

ue

600

700

800

900

1000

Gasoline Diesel

Comparison of Class 2b / Class 3 peak torque brake specific CO2 for medium-duty vehicles 1998 - 2011 calendar years.

• Data from EPA HD database. • Figure from T.J. Wallington, C.K. Lambert, W.C. Ruona, Energy Policy, in review.

• At light/moderate loads the CO2 advantage for SCR-equipped diesel will be > 10%.

Urea SCR used on majority of diesels in 2010+.

0

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120

140

2004 2005 2006 2007 2008 2009 2010 2011 2012

PGM Content Pt Equivalence

Oct 4, 2011 25

Diesel MDV Impact on Sustainability Precious Metal Usage in Super Duty DOCs

Pt rich Pd rich

2011MY J1 DOC+SCR+CDPF

2011MY J2 DOC+SCR+CDPF

DOC only

DOC +CDPF

0.00

500.00

1000.00

1500.00

2000.00

2500.00

Ford LNTResearch 2005

Ford J1 2010 Ford J2 2010

System PGM cost

NOx Catalyst Cost

Total NOx Control Cost*

* including urea hydraulics

Diesel MDV Impact on Sustainability System PGM and NOx Control Cost

Oct 4, 2011 26

DO

C+S

CR

+CD

PF P

GM

DO

C+L

NT+

CD

PF P

GM

LNT

cata

lyst

urea

+

SCR

cat

alys

t

LNT

cata

lyst

SCR

cat

alys

t

DO

C+S

CR

+ C

DPF

PG

M

urea

+

SCR

cat

alys

t

SCR

cat

alys

t

Oct 4, 2011 27

Conclusions • Strategic DOE tech funding can lead to

production components and systems • Important to assess potential early • General focus on saving and/or replacing

critical resources is effective • Tech may be used in products/ways you

did not initially envision

Oct 4, 2011 28

Next Steps for Diesel MDV • Materials cost reductions continue

– PGM reductions – substitution of Pt with Pd

• Aftertreatment efficiency improvements – catalyst durability improvements – catalyst structure improvements – heating strategies – understand non-uniform SCR aging

Oct 4, 2011 29

Further Research Needed on Small Pore Zeolite Catalysts

• Cu/CHA development enabled Cu/zeolite for automotive use • Related patents and publications:

– Zones “Zeolite SSZ-13 and its method of preparation” US4544538, 1985 – Bull et al., “Copper CHA zeolite catalysts”, US7601662, 2009 – Kwak et al., “Excellent activity and selectivity of Cu-SSZ-13 in the selective catalytic

reduction of NOx with NH3”, J. Catal. 275 (2010) 187-190 – McEwen et al., “Integrated operando X-ray and DFT characterization of Cu-SSZ-13

exchange sites during the selective catalytic reduction of NOx with NH3”, Catal. Today, in press.

Basic experimental and computational research

needed to guide rational improvement of small pore zeolites:

• wider temperature window Fe analog? • lower ammonia storage per unit volume • smaller catalyst size per unit volume

Schneider, CLEERS Telecon, Sept 2011

Oct 4, 2011 30

Acknowledgments DOE: DE-FC26-01NT41103 (2001-2005) PNNL-Ford CRADA – Freedom Car (2006-2011) Ford: Kevin Guo, Yisun Cheng, Cliff Montreuil, James Girard, Hungwen

Jen, Scott Williams, Dave Kubinski, Brendan Carberry, Rick Soltis, Devesh Upadhyay, Michiel van Nieuwstadt, Mike Levin and many others

FEV: Erik Koehler, Dean Tomazic, Phillip Adomeit

ExxonMobil: Mike Noorman, Charlie Schleyer, Rich Grosser Catalyst Suppliers: BASF, JMI, Umicore And many, many more …

Oct 4, 2011 31

References • SAE 2002-01-1868, 2004-01-1292, 2007-01-1575, 2008-01-1025, 2009-01-

0627, 2009-01-2823 • Lambert et al., DEER 2004, 2005, 2006 • Cheng et al., DEER 2010 • www.dieselexhaustfluid.com • Mattina, 16th Annual Fleet Fueling Conference, Sept 2010. • www.factsaboutscr.com • Schneider, CLEERS Telecon, Sept 2011 • dieselnet.com