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
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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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
JB-002066
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
JB-002066
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
JB-002066
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
JB-002066
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
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
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 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
JB-002066
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.