Barry J. Cooper Johnson Matthey

Environmental Catalysts and Technologies

HDD Retrofit Technologies

Asian Vehicle Emission Control Conference2004

Outline

• Diesel Engine Emissions and Control Systems

• PM Control Technologies

• NOx Control Technologies

• Conclusions

Diesel Engine Emission Control

• Diesel engine emissions consist of:– PM (Particle Matter)– NOx (Nitrogen Oxides)– CO (Carbon Monoxide)– HC (Hydrocarbons)

• Existing, high-emitting diesel engines will be in use for the next 10 to 25 years

• Retrofitting existing engines with Catalysts is the way to reduce emissions

Available PM Control Technologies

DOC System

Engine Oxicat

DPF System

20 – 50% PM50 – 90% CO & HC

Engine OxiCat DPF

> 85% PM> 80% CO & HC

Partial Filter System

Engine OxiCat PF

> 50% PM> 80% CO & HC

Available NOx Control Technologies

Exhaust Gas Recirculation System

Engine CRT Particulate Filter 40-60%

Exhaust Gas Recirculation

SCR System

Engine SCR NH3Slip

ReductantInjection

90%

Lean NOx Trap System

Engine LNTOxi 90%

Outline

• Diesel Engine Emissions and Control Systems

• PM Control Technologies– DOC technology

– DPF technology

– Advanced DPF technology

– Partial Filter technology

• NOx Control Technologies

• Conclusions

Diesel Oxidation Catalyst

Diesel Oxidation Catalysts (DOC)

• Oxidizes CO and HC to CO2 and H2O (desired)

• Oxidizes SO2 to SO3 (undesired due to formation of

Sulfate particles)

• Oxidizes toxics such as aldehydes

• Oxidizes Soluble Organic Fraction (SOF) adsorbed on

Particulates to reduce PM

• CO, HC reduction up to 90%.

• PM reduction up to 50% depending on SOF content of PM; Typically 25% on newer engines

Ceramic Catalyst

DOC in a muffler

DOC - Application Requirements

• Can work with high sulfur fuel (up to 500 ppm)

• Benefits from low S fuel (low sulfate make)

• Easy to retrofit on existing vehicles– 2 stroke & 4 stroke

• No required maintenance

DOC Performance PM

(g/bhp-hr) Reduction

CO (g/bhp-

hr) Reduction

HC (g/bhp-

hr) Reduction2-Stroke

Baseline 0.44 1.0 0.7

+ DOC 0.22 50% 0.6 40% 0.4 43%

4-Stroke

Baseline 0.073 1.11 0.115

+ DOC 0.055 25% 0.35 68% 0.014 88%

Tested at Southwest Research Institute under EPA approved FTP transient test cycle

Diesel Particulate Filter

Diesel Particulate Filter• Johnson Matthey (CRT®) Diesel Particulate

Filter

InletHead

CatalystSection

Filter Section

OutletHead

OxidationCatalyst

Wall-flowFilter

Effectiveness of NO2 and O2in Combustion of Diesel Particulate

•0

•5E-12

•1E-11

•1.5E-11

•2E-11

•2.5E-11

•3E-11

•3.5E-11

•CO

•2•I

nten

sity

•NO2 •O2

•0 •100 •200 •300 •400 •500 •600 •700

•Temperature (C)

CRT® Particulate Filter

• CRT controls CO/HC/PM

• Comprises Pre-Catalyst & Un-catalyzed Filter

• Uses NO2 produced by a pre- catalyst to burn soot in the filter at typical operating temperatures of diesel engine exhaust

• Engineered as a totally passive emission control system which requires no supplemental heat

• Requires the use of Ultra Low Sulfur fuel for maximum emission reduction and effective filter regeneration

Factors Affecting Passive CRT Application

• Exhaust temperature– 40% time at >260 C

• PM emissions– US 1991 and beyond emissions ( <0.25g/bhp.hr)

• NOx/PM ratio– >25

• Fuel sulfur level– Maximum 50 ppm

• CRT filter system needs low sulfur (< 50 ppm) diesel fuel for:– Effective filter regeneration through efficient soot combustion– Elimination of sulfate helps in very low PM emission

CRT Emission Results on NY City Transit BusDDC Series 50 Engine – NYB Cycle

1.5

6.48 7.

03

9.1

13

6.5

1.4

7.18

7.03

0.6

0.23

0.41.

4

6.95

6.86

1.6

0.9

0.5

0

2

4

6

8

10

12

14

FE (mpg)

CO2 (Kg/mile)

NOx/10(g/mile)

THC*10(g/mile)

CO (g/mile)

PM *10(g/mile)

OE w/ LSD CRT w/ ULSD Pre CRT w/ ULSD Post

Particle Size Analysis under CBD Cycle

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E+10

30 60 110 180 270 420 680 1100 1700 2600 4200 6800Size (nm)

Num

ber (

#/cc

)

OE

OE & ULSD

ULSD & CRDPF

CNG

Stable CRT Operation on Ralph’s Grocery TruckDDC S60 C10 Engine

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

Aug-99 Mar-00 Oct-00 Apr-01 Nov-01 May-02 Dec-02 Jun-03 Jan-04

Date

Pres

sure

(in

Hg)

0

44000

88000

132000

176000

220000

264000

308000

352000

396000

440000

100 125 150 175 200 210 220 230 240 250 260 270 280 290 300 310 325 350 400 425 450 500 550

Temperature, C

Freq

uenc

y, A

bsol

ute

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Freq

uenc

y, C

umul

ativ

e %

•Acceptable Exhaust Temperature Profile

•40% of time Temp > 300 C

•CRT operating with very stable & low back pressure for over 400,000 miles

CRT Maintenance• The CRT combusts soot;

lube oil ash is incombustible• Ash accumulates in the filter

and gradually increases backpressure

• The CRT filter must be cleaned periodically to remove ash

• A backpressure monitor indicates when maintenance is needed

CRT Application Distribution

Garbage trucks

Long-haul trucks

Delivery trucks

Express bus

Transit Bus

Trains

Generator sets

Advanced Diesel Particulate Filter

CCRT – Advanced CRT for Challenging Applications

• CCRT = DOC + Catalyzed Filter

• Advantages of CCRT:– Higher soot burn rate than CRT – Installed in Challenging Applications

• Low temperature applications (200 – 250oC) • Lower NOx/PM ratio

On-road Operation with CCRT SystemYosemite Water Truck with 190 hp International DT466 Engine, FT Fuel

0

150

300

450

600

750

900

1050

1200

1350

1500

010

012

515

017

520

021

022

023

024

025

026

027

028

029

030

031

032

033

034

035

036

037

540

042

545

047

550

0

Temperature (C)

Freq

uenc

y (a

bsol

ute)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Tim

e at

Tem

p (%

)

0

1

2

3

4

5

6

12/30/02 1/19/03 2/8/03 2/28/03 3/20/03 4/9/03 4/29/03 5/19/03 6/8/03 6/28/03 7/18/03 8/7/03

Date

Bac

k Pr

essu

re (i

nHg)

•Cold Exhaust Temperature Profile

•18% of time Temp > 260 C

•CCRT operating with very stable back pressure

Partial Filter Systems

Partial Filter

• Partial filtration = moderate (~50%) PM reduction• Minimize filter plugging, some PM is trapped, rest goes through

• Use variety of substrates:-•Flow through with notches •Wire mesh •Ceramic foam

• Can use in CRT or CCRT configuration for effective soot burn

• Ideally suited for retrofitting older, dirtier engines

Partial Filter

Step to filtration activity: Trash Truck with Partial Filter

porous layer made of sintered metal fiber fleece Clean outlet head on partial filter after operation

Emissions Results for Partial Filter SystemCaterpillar 3126 Engine under 13 Mode OICA cycle

0102030405060708090

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

EastWestNorth

0.0

58

0.0

11

0.0

27

0.0

43

0.0

04

0.0

01

0.0

27

4

0.0

17

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

CO/10 HC/10 NOx/100 PM

Emis

sion

s g/

mile

Engine Out

Partial Filter Out

Partial Filter Field Trial1988 MACK E7

4

4.5

5

5.5

6

6.5

7

7.5

8

8.5

6/28/03 8/17/03 10/6/03 11/25/03 1/14/04 3/4/04Date

Bac

k Pr

essu

re (i

n H

g)

0

350

700

1050

1400

1750

2100

2450

2800

3150

3500

0 100 125 150 175 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 375 400 425 450 475 500 550 600

Temperature (C)

Freq

uenc

y

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Tim

e at

Tem

p (%

)

•Old, high PM engine

•Exhaust Temperature OK

•40% of time Temp > 300 C

•Partial Filter operating with high but stable back pressure (6 – 7 in. Hg)

Outline

• Diesel Engine Emissions

• PM Control Technologies– Fuel Sulfur Effect

• NOx Control Technologies– EGRT

– SCRT

• Conclusions

EGRT

EGRT™ System• EGR = Re-circulation of part of the exhaust gas to engine intake air

• EGRT uses STT patented EGR technology in combination with the CRT particulate filter

• ULSD (< 50 ppm) fuel is required

• Over 1200 units installed in Sweden and Hong Kong– Over 125,000 miles durability proven on single units in Europe

• US introduction 2001– Over 2 years of durability proven– Over 500 units in operation in the US

Principle of Operation of EGRT

• Exhaust gas is re-circulated to the engine air intake via a low pressure cooled EGR– Clean exhaust is taken after the CRT filter

• EGR system is customized for the engine– Requires development of EGR Map – Map is developed based on limiting conditions

• NOx/PM ratio• Fuel economy

EGRT System and Throttle Valve

Intake Air In

Cooled Exhaust In

Emissions Results for EGRT SystemCummins ISL 330 Engine, FTP Cycle on Engine Dyno

0.16

0.38

0.07

0.43

0.03

0.17 0.19

0.00 0.

05

0.00

0.17 0.20

0.06

0.69

0.10

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

FE/1000 NOx/10 THC CO PM

Emis

sion

s (g

/bh

p-h

r)

Baseline (Engine w/ DOC)

w/ EGRT

w/ EGR & OE DOC (no filter)

Selective Catalytic Reduction

(SCR)

Selective Catalytic Reduction (SCR)

• Use ammonia (NH3) to reduce NOx to N2 under oxidizing conditions

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

6 NO2 + 8 NH3 7 N2 + 12 H2O

• Ammonia can be derived from a number of sources, typically urea

SCR and SCRTTM System Schematics

EngineEngine

SCR Oxidation Cat

Removal of NOX

Removal of NH3 slip if requiredRemoves CO and some HC’sand PM SOF

Urea

EngineEngine

CRT SCR Oxidation Cat

Removal of HC, CO, PMNO NO2

Removal of NOX

Removal of NH3 slip if required

Urea

SCR

SCRTTM System

Retrofit SCRT System

Exhaust Flow

Urea Air

Urea Injection

Signals to ECU Signals from ECU

ENGINE

ECU UREA INJECTION SYSTEM

Exhaust Out

CRT SCR

SCRT™ NOx Reduction Over Various Test Cycles

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

HDDT OICA AVL 8-ModeORNL

Tests

NO

x Em

issi

ons (

g/bh

p-h)

InletOutlet

3.81

0.45

3.37

0.05

2.47

0.37

SCRT System Field Demonstration

-400

0

400

800

1200

1600

2000

2400

3:36 AM 4:48 AM 6:00 AM 7:12 AM 8:24 AM 9:36 AM 10:48 AM 12:00 PM

Date

NO

x, P

PM

Exha

ust T

empe

ratu

re, º

C

Eng Out NOx Cat Out NOx Exh TempUrea injection setpoint = 250 ºC

Effect of Retrofit on Current Engines

NOx (g/bhp-hr)4 5

Part

icul

ate

Mat

ter

(g/b

hp-h

r)

1

2

Starting point1998 Engine

FEDERAL 2002 Oct.

4 3 CRT®EGRT

DOC

SCRT®

5

0.10

0.08

0.06

0.04

0.02

0.000 1 2 3 6 7 8

Conclusions

• A number of emission control catalyst technologies now exists to aid the emissions engineer in achieving very low emission levels from diesel engines

• Johnson Matthey provides a variety of PM and NOx control technologies for retrofit

– PM Control: DOC, CRT, CCRT, PF– NOx Control: EGRT, SCR, and SCRT

• Improved fuel quality especially ultra low sulfur fuel (< 50 ppm) enables use of the most advanced control strategies