Automotive Emission Automotive Emission Control TechnologyControl Technology

MikioMikio MakinoMakino

Takahiro KondoTakahiro Kondo

NGK Insulators,NGK Insulators, LtdLtdAVECC 2001Asian Vehicle Emission Control ConferenceAVECC 2001Asian Vehicle Emission Control Conference

January 30 January 30 -- February 1, 2001February 1, 2001

Bangkok, ThailandBangkok, Thailand

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CONTENTSCONTENTS

♦♦ Background of Automotive EmissionBackground of Automotive Emission

♦♦ Ceramic Substrate Properties Ceramic Substrate Properties

♦♦ Key Production ProcessKey Production Process

♦♦ Advantage of Advanced Ceramic SubstrateAdvantage of Advanced Ceramic Substrate•• Effect of Substrate GSAEffect of Substrate GSA

•• Effect of Substrate Bulk DensityEffect of Substrate Bulk Density

♦♦ CanningCanning

♦♦ ConclusionsConclusions

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Ceramic Honeycomb Substrate and Ceramic Honeycomb Substrate and Automotive Catalytic ConverterAutomotive Catalytic Converter

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Converter Location in passenger carConverter Location in passenger car

CONOx

HC

Typical Efficiency of Typical Efficiency of a Threea Three--way Cat.way Cat.

Oxygen Sensor

Typical Chemical Reaction2CO + O2 →→ CO2

2C2H6 + 7O2 →→ CO2 + 6H2O2NO + 2CO →→ N2 + 2CO2

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CONTENTSCONTENTS

♦♦ Background of Automotive EmissionBackground of Automotive Emission

♦♦ Ceramic Substrate PropertiesCeramic Substrate Properties

♦♦ Key Production ProcessKey Production Process

♦♦ Advantage of Advanced Ceramic SubstrateAdvantage of Advanced Ceramic Substrate•• Effect of Substrate GSAEffect of Substrate GSA

•• Effect of Substrate Bulk DensityEffect of Substrate Bulk Density

♦♦ CanningCanning

♦♦ ConclusionsConclusions

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Typical Material Properties ofTypical Material Properties ofCordieriteCordierite Honeycomb SubstrateHoneycomb Substrate

Item Properties

Crystal Structure Cordierite2MgO-2Al2O3-5SiO 2

Thermal Expansion(x10 - 6/ C) (40- 800 C)

< 1.0

Specific Heat (cal/g C) 0.2

Softening Temperature ( C) 1410

ThermalProperties

Melting Point ( C) 1455

Total Pore Volume (cm3/g) 0.2

Porosity (%) 35PhysicalProperties

Mean Pore Diameter (� m) 4

A-axis > 85

B-axis > 11MechanicalProperties

CompressiveStrength(kg/cm2) C-axis > 1

ThermalShockResistance

Electric Furnace --- Room Atmosphere( C Difference) > 650

A

C B

JB-002066

CONTENTSCONTENTS

♦♦ Background of Automotive EmissionBackground of Automotive Emission

♦♦ Ceramic Substrate Properties Ceramic Substrate Properties

♦♦ Key Production ProcessKey Production Process

♦♦ Advantage of Advanced Ceramic SubstrateAdvantage of Advanced Ceramic Substrate•• Effect of Substrate GSAEffect of Substrate GSA

•• Effect of Substrate Bulk DensityEffect of Substrate Bulk Density

♦♦ CanningCanning

♦♦ ConclusionsConclusions

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Production Process of Ceramic HoneycombProduction Process of Ceramic Honeycomb

Raw MaterialPreparation

Forming -- Drying Firing

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Extrusion MethodExtrusion MethodCeramic Honeycomb Ceramic Honeycomb

Extrusion DieExtrusion Die

Clay Flow

Connecting Point

Clay Flow

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Orientation ofOrientation of CordieriteCordierite CrystalCrystal

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CONTENTSCONTENTS

♦♦ Background of Automotive EmissionBackground of Automotive Emission

♦♦ Ceramic Substrate Properties Ceramic Substrate Properties

♦♦ Key Production ProcessKey Production Process

♦♦ Advantage of Advanced Ceramic SubstrateAdvantage of Advanced Ceramic Substrate•• Effect of Substrate GSAEffect of Substrate GSA

•• Effect of Substrate Bulk DensityEffect of Substrate Bulk Density

♦♦ CanningCanning

♦♦ ConclusionsConclusions

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Pressure Drop and Geometric Surface AreaPressure Drop and Geometric Surface Area12mil

0

1

2

3

4

10 15 20 25 30 35 40GEOMETRIC SURFACE AREA , cm2/cm3

RE

LA

TIV

E P

RE

SS

UR

E D

RO

P,(

6.0/

400=

1.0)

8mil

6mil

4mil

300cpsi400cpsi

600cpsi

Formula for Room Temperature

∆ : Pressure Drop (mm Aq)V : Gas Velocity (m/s)

Q : Gas Flow Rate (N 3/min )L : Substrate Length (mm)D : Substrate Diameter (mm)HD : Hydraulic Diameter (mm)OFA : Open Frontal Area

∆ PL

H D

V

O F A= x

−5 224 10 2

0 829

1 631

1 405

.. . . . .

.

.

.

<Experimental Equation>

Under Production Cell Density

Wall Thickness

Wall Thickness

Cell Pitch

(15% lower BD)

(30% lower BD)

xx

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1100mm

O2 Sensor

Typical Effect of GSA Catalytic Converter LayoutsCatalytic Converter Layouts

Under- Floor (U.F.)

Close- Coupled (C.C.)

Secondary Air Injection at Cold Start

400mm

O2 Sensor

TLEV 2.2Liter L- 4

Gasoline E/G

ULEV 2.3Liter L- 4

Gasoline E/G

Pd/Pt/Rh Catalyst 1.0 liter 106Dia.x114Lmm

Original lean A/F Control at Cold Start

Pd/Pt/Rh Catalyst 1.0 liter 106Dia.x114Lmm

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Typical Effect of GSA on NMHC (TLEV)

0.03

0.04

0.05

0.06

0.07

20 25 30 35 40

GSA of C.C.Substrate, cm2/cm3

TO

TA

L N

MH

C-E

mis

sio

ns

,g/m

ile 5/300(Prototype)

4/6004/400

6/400

Converter: 1.0 liter C.C.-only

Substrate : 106 Dia. x 114 L mm

Catalyst : Pd/Pt/Rh, 150g/ft 3

Aging : max. 850oC x 50hrs

Test Vehicle : TLEV 2.2 liter L- 4 Gasoline

Cold-Start Control: Secondary Air Injection

Test Cycle : FTP- 75

O2 Sensor

400mm

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Typical Effect of GSA on NOx (TLEV)

0.1

0.15

0.2

0.25

0.3

0.35

20 25 30 35 40

GSA of C.C.Substrate, cm2/cm3

TO

TA

L N

Ox

Em

issi

on

s ,g

/mile

4/4006/400

5/300(Prototype)

4/600

Converter: 1.0 liter C.C.-onlySubstrate : 106 Dia. x 114 L mm

Catalyst : Pd/Pt/Rh, 150g/ft 3

Aging : max. 850 oC x 50hrs

Test Vehicle : TLEV 2.2 liter L- 4 GasolineCold-Start Control: Secondary Air InjectionTest Cycle : FTP- 75

O2 Sensor

400mm

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Typical Effect of GSA on NMHC (ULEV)

0.02

0.04

0.06

0.08

0.1

20 25 30 35 40GSA of U.F.Substrate, cm2/cm3

TO

TA

L N

MH

C-E

mis

sio

ns

,g/m

ile

5/300 (Prototype)4/400

6/400

4/600

Converter: 1.0 liter U.F.-only

Substrate : 106 Dia. x 114 L mm

Catalyst : Pd/Pt/Rh, 150g/ft 3

Aging : max. 850oC x 50hrs

Test Vehicle : ULEV 2.3 liter L- 4 Gasoline

Cold-Start Control: Original lean Start

Test Cycle : FTP- 75

1100mm

O2 Sensor

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Typical Effect of GSA on NOx (ULEV)

0.1

0.2

0.3

0.4

20 25 30 35 40

GSA of U.F.Substrate, cm2/cm3

TO

TA

L N

Ox

Em

issi

on

s ,g

/mile

5/300 (Prototype)

6/4004/400

4/600

Test Vehicle :ULEV 2.3 liter L- 4 GasolineCold-Start Control: Original lean StartTest Cycle : FTP- 75

Converter: 1.0 liter U.F.-onlySubstrate : 106 Dia. x 114 L mm

Catalyst : Pd/Pt/Rh, 150g/ft3

Aging : max. 850oC x 50hrs 1100mm

O2 Sensor

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CONTENTSCONTENTS

♦♦ Background of Automotive EmissionBackground of Automotive Emission

♦♦ Ceramic Substrate Properties Ceramic Substrate Properties

♦♦ Key Production ProcessKey Production Process

♦♦ Advantage of Advanced Ceramic SubstrateAdvantage of Advanced Ceramic Substrate•• Effect of Substrate GSAEffect of Substrate GSA

•• Effect of Substrate Bulk DensityEffect of Substrate Bulk Density

♦♦ CanningCanning

♦♦ ConclusionsConclusions

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Typical Effect of Sub. Bulk DensityTypical Effect of Sub. Bulk DensityConverter Configuration for Emission Test

Secondary Air Injection

Close-Coupled Converter (0.69dm3)

6/400, 4/400, 4/600

Pd only Catalyst

Under-floor Converter (1.6dm3)

6/400

For 100sec after Engine Ignition at 120 liter/min

air flow

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0

10

20

30

40

50

60

70

80

90

0 500 1000 1500 2000 2500

Time (seconds

Sp

eed

�mile

/ho

ur

�

Cold-Transient

(Bag-1)

Stabilized

(Bag-2)

Soak Hot-Transient

(Bag-3)

Bag-1A

Ref. U.S. FTPRef. U.S. FTP--75 Test Cycle75 Test Cycle

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Effect of Sub. Bulk Density

0

0.02

0.04

0.06

0.08

0.2 0.3 0.4 0.5

Bulk Density of C.C.Substrate (g/cm3 )

Bag

-1A

& T

ota

l HC

Em

issi

on

s (g

/mile

)

C.C.Substrate: Volume 0.69dm3

U.F.Substrate: Volume 1.70dm3 6mil/400cpsi

Catalyst System: Pd-onlyCold-Start Control: Secondary Air

4/400

4/600

Bag-1A

6/400

Total

JB-002066

CONTENTSCONTENTS

♦♦ Background of Automotive EmissionBackground of Automotive Emission

♦♦ Ceramic Substrate Properties Ceramic Substrate Properties

♦♦ Key Production ProcessKey Production Process

♦♦ Advantage of Advanced Ceramic SubstrateAdvantage of Advanced Ceramic Substrate•• Effect of Substrate GSAEffect of Substrate GSA

•• Effect of Substrate Bulk DensityEffect of Substrate Bulk Density

♦♦ CanningCanning

♦♦ ConclusionsConclusions

JB-002066

Typical Converter ConfigurationTypical Converter ConfigurationHeat Shield

Sealing Rope Intumescent Mat

Ceramic CatalystGas

Air Gap or Insulation

Heat Shield

L-type Mesh

Intumescent Mat

Ceramic Catalyst

Gas

Air Gap or Insulation

Metallic Wire Mesh

200

250

300

350

400

450

750 800 850 900 950 1000 1050 1100

Catalyst Bed Temperature,C

Co

nve

rter

Ski

n T

emp

erat

ure

, C

Air Gap

Insulation

Converter Skin Temp.on above converter

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Typical Canning Method

Clam-Shell Stuffing Tourniquet

Can

CatalystMatCan

Mat

Catalyst

Mat

Can

Catalyst

GuideTensionCompression

Compression

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Mounting Pressure Behavior of the Mounting Material

0

2

4

6

8

10

12

14

16

18

20

0 200 400 600 800 1000

Mat Temperature, C

Res

idu

al P

ress

ure

, Kg

/cm

2

Non-Intumescent Mat

Intumescent Mat

Wire Mesh

Initial Pressure : 2 kg/cm 2

Load CellElectricalFurnaceMat

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OverOver--Heat Protection Converter Design Heat Protection Converter Design

Exhaust Gas

Intumescent Mat

Heat Conduction

Sealing Rope

Ceramic Catalyst

Double - Wall Cone Structure

200

250

300

350

400

450

750 800 850 900 950 1000 1050 1100

Catalyst Bed Temperature,C

Co

nve

rter

Ski

n T

emp

erat

ure

, C

Air Gap Heat Shield

Insulated Heat Shield

Double-Wall Cone Structure

Converter Skin Temp.on converter

JB-002066

CONTENTSCONTENTS

♦♦ Background of Automotive EmissionBackground of Automotive Emission

♦♦ Ceramic Substrate Properties Ceramic Substrate Properties

♦♦ Key Production ProcessKey Production Process

♦♦ Advantage of Advanced Ceramic SubstrateAdvantage of Advanced Ceramic Substrate•• Effect of Substrate GSAEffect of Substrate GSA

•• Effect of Substrate Bulk DensityEffect of Substrate Bulk Density

♦♦ CanningCanning

♦♦ ConclusionsConclusions

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Conclusions 1 ♦ The honeycomb structure can provide maximum

contact surface between a gas and a solid with minimum pressure drop.

♦ Cordierite honeycomb can withstand severe operating conditions including high temperature.

♦ Cordierite honeycomb has been contributing to air pollution control worldwide for automotive and industrial emission sources.

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Conclusions 2

♦ Thin wall and high cell density substrates, 4mil/400cpsi, 4mil/600cpsi, shows significant catalytic performance improvement.

♦ It is demonstrated the bulk density and geometric surface area are the most significant factors for reduction of HC andNOx emissions.