diesel oxidation catalyst (doc) system for pm control · diesel oxidation catalyst (doc) system for...

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Diesel Oxidation Catalyst (DOC)System for PM Control

Satoshi SumiyaYasunori Imada

Johnson Matthey Japan, Environmental Catalyst and Technologies

2

Presentation Outlines• Background

* Social requirements in Japan* Importance to develop robust PM control technology

for in use diesels

• Experimental Procedure

• Test Results1. Impact of DOC on PM Emission (work with Kawasaki)2. Impact of DOC on Unregulated Hydrocarbons (work with TMG)3. Newly Developed DOC + CSF (Catalysed Soot Filter) Using

Ceramic Foam

• Conclusions

2

3

Comparison of Diesel Emission Control Technologies

--++++++++CRT + SCR (SCRTTM)

-+++++++++SCR

+--++++++CR-DPF (CRTTM )

--+++++++NOx trap

-+++++++Lean NOx catalyst

+++-++++Fuel Additive + DPF

++++-+++++DOC

NOxPMTHCCO

Practicalpossibility

S tolerance

Emission Reduction Capability

++ : very good, + : good, - : not suitable

4

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1996 1998 2000 2002 2004 2006 2008

PM e

mis

sion

(g/k

Wh)

Emission standardfor newly registered vehicle

Tokyo Local regulation valuefor in-use diesels

Legislation for In-Use HDD Enforced by Tokyo Metropolitan Government

-60% -70%

1994 standard

-30%

3

5

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0NOx g/ kWh

PM g

/kW

h

USEUJPCARB_BUSNOx/ PM=10NOx/ PM=20NOx/ PM=50

2000

20052008

2004

1998Truck

1998Bus

1999

2004

2007?

2007ULEV(Nox+HC)

2008 2005 2003 2000

1996

NOx/ PM=50

NOx/ PM=20

NOx/ PM=10

Past and Future NOx and PM Legislations

NOx/PM ratio on in use diesels in Japan are around 10 to 20.

NOx/PM ratio on in use diesels in Japan are around 10 to 20.

6

How to Improve ? -DOC + CSF System Principle-

4

Temperatures Conditions DuringLow Temperature Cycle

150

170

190

210

230

250

270

0 60 120 180 240 300 360 420 480 540 600 660 720 780 840 900 960Time (s)

Tem

pera

ture

(o C)

Temperature Before Catalyst

Temperature After Catalyst

Temperature After Filter

Ref : R. Allansson et.al., SAE Paper 2002-01-0428

8

Low Temperature Cycle (40 hrs) Performance in MK1 Fuel

0

20

40

60

80

100

120

140

160

0 5 10 15 20 25 30 35 40 45

Time (Hours)

Bac

k Pr

essu

re (m

bar)

Bare Filter Alone

CSF Alone

CRT

DOC + CSF

Ref : R. Allansson et.al., SAE Paper 2002-01-0428

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9

Experimental Conditions

30 cpi

200

Cell density (cpsi)

0.7

0

Pt(g/L)

CatalyzedCordielite foam filter

OD:240X

ID:120X

L : 200

2.6400D:267

XL:152

13Engine Bench

Test3

Non-coatCordielite

Wall-through

D:267X

L:3052.6400

D:267X

L:15210

Citybus

Test2

2400D:191

XL:178

5Garbage truck

Test1

MemoSize(mm)

PGM (g/L)

Cell density (cpsi)

Size(mm)

Engine size (L)

Vehicle type

CSFDOCVehicle/Engine

*Less than 50 ppm S fuel was used for all test. Test 1 : Collaboration work with Kawasaki-city.Test 2 : Collaboration work with Tokyo metropolitan Research Institute for Environmental Protection.

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Specifications of Tokyo Metropolitan City Bus

Engine Maker Hino

Engine Type M10U (DI, 6 cylinders)

Engine Displacement 9.88 L

Maximum Power 230 PS / 2500 rpm

Maximum Torque 70 kgm / 1500 rpm

Registration Feb.,1993 (HT2MLA41043)

Vehicle Specifications

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11

Tokyo City Mode 2, 5, 8 and 10

0

20

40

60

80

0 200 400 600 800 1000 1200

Operation time / sec

Vec

hicl

e sp

eed

/ km

/h

Tokyo City Mode #2Average speed : 8.4 km/h

0

20

40

60

80

0 200 400 600 800 1000 1200


Vec

hicl

e sp

eed

/ km

/h


0

20

40

60

80

0 200 400 600 800 1000 1200


Vec

hicl

e sp

eed

/ km

/h


0

20

40

60

80

0 200 400 600 800 1000 1200Operation time / sec

Vec

hicl

e sp

eed

/ km

/h

Tokyo City Mode #10Average speed : 44.4km/h

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Temperature Frequencyon Tokyo City Modes

0

10

20

30

40

50

180 220 260 300 340 380 420 460 500

Temperature at the inlet of CRT / C

Freq

uenc

y / %

Tokyo City Mode #2

0

10

20

30

40

50

180 220 260 300 340 380 420 460 500

Temperature at the inlet of CRT / C

Freq

uenc

y / %

Tokyo City Mode #5

0

5

10

15

20

180 220 260 300 340 380 420 460 500

Temperature at the inlet of DOC / C

Freq

uenc

y / %

Tokyo City Mode #8

0

5

10

15

20

180 220 260 300 340 380 420 460 500Temperature at the inlet of DOC / C

Freq

uenc

y / %

Tokyo City Mode #10

>300C : 5%>300C : 19%

>300C : 32% >300C : 74%

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13

Engine Map Points with Weighting Factor on Japanese D13 Mode

0

20

40

60

80

100

0 20 40 60 80 100

Engine Speed / %

Engi

ne L

oad

/ %

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Test Results

- PM reduction Efficiency over DOC -

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15

PM Reduction Efficiencies on DOC over Kanagawa-Prefecture Modes

Conventional DOC testing on Garbage Truck

(5L engine)

0

0.1

0.2

0.3

0.4

1 2

PM e

mis

sion

/ g/

km

Engine baseWith DOC

Low speed mode(Average : 12.65 km)

High speed mode (Average : 24.1 km)

- 63%

- 52%

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Emitted Carbonacious Matter over Kanagawa-Prefecture Modes

Garbage Truck

(5L engine)

0

0.1

0.2

0.3

0.4

Engine base With catalyst Engine base With catalyst

Emitt

ed c

arbo

naci

ous m

atte

r / g

/km

EC OC

Low speed mode (Average : 12.65 km)

High speed mode(Average : 24.1 km)

- 95%

- 95%

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Emitted PAHs and Benzo-(a)-Pylene over Kanagawa-Prefecture Modes

0

20

40

60

80

100

120

140

160

Low speed High speed

Em

itted

PA

Hs/

ug/

km

Engine baseWith catalyst



0.0

0.5

1.0

1.5

2.0

2.5

3.0

1 2

Em

itted

Ben

zo-(

a)-p

ylen

e/ u

g/km

Engine baseWith catalyst



- 78%

- 63%

- 61%

- 77%

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Unregulated Hydrocarbons Reduction Efficiencies over Tokyo City Modes

* City Bus test : 10L engine

0

20

40

60

80

100

Mode #2 Mode #5 Mode #8 Mode #10

Red

uctio

n ef

ficie

ncy

/ %

0

20

40

60

80

100


Red

uctio

n ef

ficie

ncy

/ %

FormaldehydeAcetaldehyde

0

20

40

60

80

100


Rre

duct

ion

effi

cien

cy /

%

1, 3-Butadiene

0

20

40

60

80

100


Red

uctio

n ef

ficie

ncy

/ %

Benzene

0

20

40

60

80

100


Red

uctio

n ef

ficie

ncy

/ %

0

20

40

60

80

100


Red

uctio

n ef

ficie

ncy

/ %

FormaldehydeAcetaldehyde

0

20

40

60

80

100


Rre

duct

ion

effi

cien

cy /

%

1, 3-Butadiene

0

20

40

60

80

100


Red

uctio

n ef

ficie

ncy

/ %

Benzene

10

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Vehicle Test Summary

1. DOC installed on garbage truck can reduce more than 40% PM. The reduction efficiency depends upon the vehicle driving condition.

2. DOC mainly reduced organic carbons (SOF) into PM and no effective function to reduce elementary carbons (Soot).

3. DOC effectively reduced many kinds of unregulated hydrocarbons at various driving condition.

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- PM reduction Efficiency over DOC + CSF -

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[PM combustion rate] ≦　[PM accumulation rate]

Increase NOx concentration

Improve temperature condition

Catalyzed filter

Reduce PM emissions

Low efficiency filter

（Out of control)

（Dual skin tube)

（Pt base catalyst)

（Out of control)

（Wire mesh, Foam type)

≧

How to Improve ?

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1. Use NO many times in the unit Frame by frame reaction of NO2 with C

2. Larger geometrical surface area (GSA) than wall-through type

DPF, and can increase number of contact point with PM

Foam filter Wall-through filter#30 12/200 8/300

GSA(cm2/cm3) 43 9 12

3. Acceptable backpressure level as CSF

System Concept of DOC+CSF Using Foam Filter

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23

NONO+CO2

NO2

NO

NO2

NO2

NO+CO2

NO2

Pt

Soot

Frame

NO2 Reaction with C in Coated Foam Filter

* Frame by Frame Reaction of NO2 with C

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#30#20

#13#6

Outward of Cordielite Ceramic Foams

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Plate Stack and Cylindrical Design

Plate stack Type

IN

IN

Cylindrical Type

Efficiency High Low(in parallel)/High(in series)

D.Pressure High Low

Canning Difficult Easy(Mechanical strength)

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0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

1 2 3 4

PM w

eigh

t ove

r D

13 m

ode

/ mg SOF

Soot+Sulfates

Engine base With DOC + Foam filter(OD240 X ID90, 20 cpi)

PM Emissions over D13 mode

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PM Emissions over Tokyo City Mode #5- Blow-Off Effect while Transient Test -

0

0.2

0.4

0.6

0.8

1

PM m

ass o

ver

TM

G m

ode#

5 / m

g

Soot SOF

Engine outDOC

+CSF

-43%

With DOC + Foam filter(OD240 X ID90, 20 cpi)

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PM Emissions over D13 Mode and Tokyo City Mode#5

0.0

0.2

0.4

0.6

0.8

PM E

mis

sion

/ g/

kwh

D13 mode TMG#5 mode

Engine out Engine outA: OD240 X ID90 B

-37

%

-44

%

-45

%

-56

%

A: OD240 X ID90

0.0

0.2

0.4

0.6

0.8

PM E

mis

sion

/ g/

kwh

D13 mode TMG#5 mode

Engine out Engine outA: OD240 X ID90 B

-37

%

-44

%

-45

%

-56

%

A: OD240 X ID90

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Conclusions

1. DOC can reduce part of the PM, especially organic carbons. The reduction efficiency depends upon the SOF content and temperature at driving condition.

2. DOC effectively reduced unregulated hydrocarbons emitting from diesel engines. This is additional advantage to use DOC, not only for reducing PM mass.

3. System performance of newly developed DOC + catalyzed foam filter was demonstrated and showed promising results.

* On this system, around 50% PM reduction efficiency was confirmed on both steady state mode and transient modes.

* This system enable to cover the specific PM reduction target in between DOC and conventional wall-through DPF.

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Acknowledgments

• Tokyo Metropolitan Research institute for Environmental Protection is acknowledged for permission to make presentation and for help with the testing.

• Environmental Protection Bureau, Pollution Control Department, Automobile Policy Section in Kawaski-City, Kanagawa-prefecture is acknowledged for permission to make presentation and for help with the testing.

• Bridgestone Corporation is acknowledged for permission to make presentation and for help with the supplying foam filters.

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Thank you !

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