EPA/AA/CTAB/87-01
Technical Report
Durability of Low Cost Catalysts
For Methanol-Fueled Vehicles
By
Robert M. Heavenrich
Robert I. Bruetsch
Gregory K. Piotrowski
October 1987
NOTICE
Technical Reports do not necessarily represent final EPA
decisions or positions. They are intended to present technical
analysis of issues using data which are currently available.
The purpose in the release of such reports is to facilitate the
exchange of technical information and to inform the public of
technical developments which may form the basis for a final EPA
decision, position or regulatory action.
U. S. Environmental Protection Agency
Office of Air and Radiation
Office of Mobile Sources
Emission Control Technology Division
Control Technology and Applications Branch
2565 Plymouth Road
Ann Arbor, Michigan 48105
-------
\ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
/ ANN ARBOR, MICHIGAN 48105
OFFICE OF
AIR AND RADIATION
December 14, 1987
MEMORANDUM
SUBJECT: Exemption From Peer and Administrative Review
FROM: Karl H. Hellman, Chief
Control Technology and Applications Branch
TO: Charles L. Gray, Jr., Director
Emission Control Technology Division
The attached report entitled "Durability of Low Cost
Catalysts for Methanol-Fueled Vehicles," (EPA-AA-CTAB-87-01)
describes catalysts tested at MVEL for efficiency at zero miles
and then aged 12,000-14,000 miles in Los Angeles, California as
part of a California Energy Commission sponsored program in
cooperation with Ford, Toyota, and EPA. This report compares
FTP and HWY test results at the 12,000-14,000 mile point with
the zero-mileage results.
Since this report is concerned only with the presentation
of data and its analysis and does not involve matters of policy
or regulations, your concurrence is -requested to waive
administrative review according to the policy outlined in your
directive of April 22, 1982.
Approved: : Date
Charles L. Gray, Jr.", Dir., ECTD
Attachment
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Background
The objective of the project was to evaluate the
efficiency durability of low cost catalysts operated on-
methanol-fueled vehicles in fleet service. The catalysts were
first tested at EPA for efficiency at zero miles. [1]* The
catalysts were then operated on cars in Los Angeles,
California. After 12,000-14,000 miles were accumulated on the
catalysts, they were removed from the cars and shipped back to
EPA for further testing. This report compares the tests at the
12,000-14,000 mile point with the zero-mileage results. The
California Energy Commission, Engelhard Specialty Chemical
Division, Johnson Matthey Catalytic Systems Division, Ford and
Toyota cooperated with EPA in this effort.
Description of Catalysts
Two catalyst types were tested in this program. Both
catalyst types were monoliths with substrates of 400 cells per
inch and a 6-mil wall thickness. Both were composed of two
separate biscuits in a single container. Each biscuit has an
oval cross section measuring 3.15 by 4.75 inches. The front
biscuit is 2.98 inches long and the rear biscuit 4.3 inches
long for a total substrate volume of 92.8 cubic inches.
Both catalyst types had loadings of 20 grams of noble
metal per cubic foot. One catalyst type contained only
palladium (Pd); the other contained platinum (Pt) and palladium
in a ratio of 3:2. Using standard CTA3 notation, these are
denoted Pd(20) and 3Pt:2Pd(20), respectively.
A total of eight catalysts (four of each type) were
prepared for this project. Three of the four units of each
type were shipped to California in January 1984 without any
testing at EPA. One catalyst of each type was zero-mileage
tested at EPA before being shipped to California in April
1984.**
Table 1 gives a listing of the catalysts that were
installed on the fleet vehicles for mileage accumulation: the
catalyst type, formula, catalyst serial number, vehicle
identification number (VIN), fleet vehicles, license plate, and
odometer reading when the catalyst was removed from the car.
* Numbers in brackets denote references listed at the end of
the report.
** The two catalysts zero-mileage tested at EPA had serial
numbers NPN 7-16 (PD(20» and 9K-8579, EPA 2648
(3Pt:2Pd(20)). The catalysts were installed on the aging
vehicles in January 1984 by Bill Stroppe & Son, Long
Beach, CA, but the initial odometer readings were not
recorded.
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-2-
Table 1
Sample Numbers of Catalysts Aged on Fleet Vehicles
Sample Catalyst
Number Type Formula
1 OX Pd(20)
2 TWC* Pd(20)
3 TWC* 3Pt:2Pd
(20)
4 OX 3Pt : 2Pd
(20)
5 OX 3Pt : 2Pd
(20)
6 OX Pd(20)
Serial No.
NPN 6-15
NPN 8-17
9K-8583
EPA2650
9K-8580
EPA2649
9K-8584
EPA2651
NPN 3-12
Vehicle License
Ident . No. Plate No.
1FABP137 0868571
XDW237350
1FABP137 0868573
XDW237378
1FABP137 0868572
6DW237359
1FABP137 0868570
3DW237349
1FABP137 0868575
9DW237405
1FABP137 0868574
9DW237386
Odometer
Reading
13306 .3
12732.0
14249 . 2
12493.8
11809.4
13247.9
No thermactor belt.
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-3-
For each catalyst used as an oxidizing catalysts, the
downstream air tube was flush mounted with the exhaust pipe to
put air (from the air pump) into the exhaust at least six
inches upstream of the catalyst. For each catalyst used as a
three-way catalyst, the belt to the air pump was removed, and
the downstream air tube was capped.
EPA Test Vehicle
The catalysts were tested at EPA on a 1982 Toyota Cressida
described in Table 2. This vehicle was modified by Toyota to
operate on methanol fuel. Additional modifications were made
to the Cressida's exhaust system to facilitate installation of
the catalysts and to allow for the installation of
thermocouples before and after the catalyst. Fuel injectors
were changed by Toyota in March 1984, April 1984, May 1984,
June 1984, July 1984, August 1986, and August 1987.
Zero Mileage Test Procedure
The initial plan called for testing of the catalysts over
the following sequence:
1975 Federal Test Procedure (FTP)
Highway Test Procedure (HWY)
10 mph steady state
20 mph steady state
30 mph steady state
After baselining the test car without a catalyst, the
sequence was performed three times for each catalyst at each of
two exhaust oxygen levels. The higher of the two exhaust
oxygen levels was measured at the catalyst inlet using a Sun
oxygen analyzer and was obtained at 30 mph steady state. The
two oxygen levels were stoichiometry (or near 0 percent) and
about 6 percent. The air pump was installed (March 1984) in
order to provide the 6 percent oxygen level. By testing at
different exhaust oxygen levels we could, therefore, evaluate
each catalyst as a three-way catalyst and also as an oxidation
catalyst.
As the project proceeded, steady-state test points were
deleted in order to speed up the testing. HC, CO, NOx, MPG,
methane, and aldehydes were initially measured over each test
in the sequence. Measurement for aldehydes was deleted for
some of the steady-state tests. The apparatus used to measure
HC, CO, NOx, and aldehyde emissions is described in references
2 and 3.
The test fuel used in this program was pure methanol.
Five batches of methanol were consumed in this phase of the
project; one was analyzed, and described in reference 2. The
gasoline used in the cold-start system of the Toyota is
Indolene clear (unleaded) and meets the EPA specifications for
that fuel (40 CFR 86.307-82).
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Table 2
Emission Test Vehicle Description
1982 Toyota Cressida (methanol-fueled)
Vehicle Identification Number: MX62-083780
Engine:
Type
Bore x Stroke
Displacement
Compression Ratio
Fuel Metering
Drive Train:
Transmission Type
Axle Ratio
Chassis:
Type
Tires
Curb Weight
Test weight (ETW)
Actual Dynamometer
Horsepower
4-stroke Otto cycle, in-line 6
83 . 0 x 85.0 mm
2759 cc (168 CID)
10.0: 1
Two separate fuel injection
systems. (The main fuel
injection system uses pure
methanol; a separate
cold-start fuel injection
system uses pure gasoline.
4-speed automatic with
overdrive
3.73
4-door sedan
Dunlop 185/70SR14 steel
belted radials
2,855 pounds
3,000 pounds
10.3
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-5-
Zero Mileage Test Results
Tables 3 and 4 present average zero-mile FTP emissions and
efficiencies. (More detailed data on these tests is presented
in reference 2.) Due to the substantial shift in engine-out
emissions following the replacement of the fuel injectors, the
data in these tables is limited to those tests after the change
in injectors. Tables 5 and 6 present zero-mileage highway
emissions and efficiencies* for the two catalysts.
Table 7 contains zero-mile efficiencies for each bag of
the FTP.
Mileage Accumulation Vehicles
Mileage accumulation was performed on six model year 1983
methanol-fueled Escorts (Tables 8 and 9). These cars were part
of a fleet based at the Los Angeles airport and driven by State
of California employees. Initial maintenance on the vehicles
was performed under contract by Thrifty Rent-A-Car. After
January 1, 1986, the maintenance was performed by Dollar
Rent-A-Car.
Mileage accumulation on the Escorts was very uneven. Some
selected cars were signed out almost continuously, while some
were utilized only on those occasions when a great number of
cars were needed. The level of maintenance of these cars
apparently dropped off appreciably before January 1986.
Appendix A gives a summary of the maintenance performed on each
of the Escorts used in this project.
A Ford Motor Company engineer examined 17 of the fleet
Escorts- in June 1985 and observed a number of maintenance
problems with these vehicles. Commonly observed problems were:
1. Carburetors had been adjusted to very rich idle
mixtures; and
2. Ignition timing which should have been maintained at
14° BTDC had been retarded to approximately 8°.
Thus, the cars were operated by a number of drivers, on a
number of unknown routes, under a number of different driving
conditions, often under conditions of maintenance different
from those recommended by the manufacturer.
Catalyst efficiency is defined as the percent difference
between the emissions measured with and without a catalyst.
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-6-
Table 3
Summary of Average Zero-Mile
at Different Oxygen
Catalyst
None
3Pt:2Pd(20
Pd(20)
HC (g/mi)
Oxygen
0% 6+%
.99
) .24 .27
.29 .28
Aid. (mg/mi)
Oxygen
0% 6+%
283.6
37.3 264.6
41.0 236.5
Table 4
FTP Emissions
Levels
CO (g/mi)
Oxygen
0% 6%
8.85
2.80 0.34
1.97 0.72
NOx (g/mi)
Oxygen
0% 6%
2.08
0.51 1.35
0.32 1.32
Zero-Mile FTP Catalyst Efficiency (percent)
at Different Oxyqen Levels
Catalyst
3Pt:2Pd(20
Pd(20)
HC (g/mi)
Oxygen
0% 6+%
) 76 73
71 72
Aid. (mg/mi)
Oxygen
0% 6+%
87 7
86 17
Table 5
Summary of Average Zero-Mile
at Different Oxyqen
Catalyst
None
3Pt:2Pd(20
Pd(20)
HC (g/mi)
Oxyqen
0% 6+%
.42
) .01 .01
.01 .01
Aid. (mg/mi)
Oxygen
0% 6+%
167.2
5.4 40 . 4
7.3 31.9
CO (g/mi)
Oxygen
0% 6%
68 96
78 92
HWY Emissions
Levels
CO (g/mi)
Oxyqen
0% 6%
6.33
. 0 . 74 0 . 00
0.74 0.02
NOx (g/mi)
Oxygen
0% 6%
75 35
85 36
NOx (g/mi)
Oxygen
0% 6%
1.88
0.26 1.06
0.06 1.06
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-7-
Table 6
Zero-Mile Catalyst Efficiency (percent) Over HWY
at Different Oxygen Levels*
HC (g/mi)
Oxygen
Catalyst
3Pt:2Pd(20)
Pd(20)
0%
98
98
6+%
97
97
Aid. (mg/mi)
Oxygen
0%
97
96
6+%
76
81
CO (g/mi)
Oxygen
0%
88
88
6%
99 +
99+
NOx (
g/mi)
Oxygen
0%
86
97
6%
44
43
Table 7
Zero-Mile Catalyst Efficiency (percent) Over FTP
By Bag at Different Oxygen Levels*
HC Effic.
Run As :
TWC OX
Aid. Effic.
Run As :
TWC OX
CO Effic.
Run As :
TWC OX
NOx Effic.
Run As :
TWC OX
3Pt:2Pd(20):
Bag 1 49 48 67 8 54 87 65 19
Bag 2 97 94 96 5 73. 100 82 50
Bag 3 88 78 90 8 74 98 77 31
Pd(20):
Bag
Bag
Bag
1
2
3
38
97
84
44
97
81
65
96
85
1
39
-24
54
90
78
77
99
93
72
92
87
18
53
34
"TWC" denotes a three-way catalyst (0 percent oxygen
level), and "OX" denotes an oxidizing catalyst (6+ percent
oxygen level).
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-8-
Table 8
Mileage Accumulation Vehicle Description
1983 Methanol-Fueled Ford Escorts
Engine:
Type
Bore x Stroke
Displacement
Compression Ratio
Fuel Metering
Drive Train:
Transmission Type
Chassis:
Type
Vehicle Identification
Numbers
4-stroke Otto cycle, in-line 4
80.0 x 79.5 mm
1.6 liters (98 CID)
11.8:1
2-barrel carburetor
3-speed automatic transaxle
4-door station wagon or
4-door sedan
1FABP1373DW237349
1FABP137XDW237350
1FABP1376DW237359
1FABP137XDW237378
1FABP1379DW237386
1FABP1379DW237405
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-9-
Table 9
Modifications Made to the Model Year 1983
Gasoline-Fueled Escorts to Convert Them to Methanol-Fueled
Fuel System
Fuel Tank:
Same design as gasoline-fueled Escort, but it is made of
stainless steel for corrosion protection.
Fuel Tank Sending Unit:
Same design as standard unit, but it is nickel plated to
prevent corrosion and has nickel plated brass float.
Fuel Tank Straps:
Same design as standard model, but the straps are coated
with nylon to prevent dissimilar metal corrosion of the
stainless steel methanol fuel tank.
Fuel Lines:
Same routing as standard Escort, but the lines are
fabricated from stainless steel to prevent corrosion.
Fuel Pump:
Same design as standard unit, but all metallic parts have
been made corrosion resistant through nickel plating, and all
plastic and rubber parts are made from a material which will
withstand methanol.
Carburetor:
The carburetor is stock, modified and recalibrated to meet
the higher fuel-flow requirements of the methanol engine. All
parts have been nickel plated or manufactured from a material
which is compatible with fuel methanol. For example, idle
adjusting needles and throttle shafts are made of stainless
steel. The float unit is an acetal hollow design and replaces
the standard unit.
Carburetor Spacer :
A rectangular spacer plate is installed between the
carburet jr base and intake manifold. This plate uses a round
electrical heating unit which replaces the square heating unit
used on the gasoline-fueled engine.
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-10-
Table 9 (cont'd)
Modifications Made to the Model Year 1983
Gasoline-Fueled Escorts to Convert Them to Methanol-Fueled
Engine
Basic Engine:
The engine that powers the methanol vehicle is the same
basic design as the Escort's gasoline-fueled l.6L high-output
(HO) engine.
The compression ratio has been increased from 8.8:1 to
11.8:1. This was accomplished by installing the piston from a
European 1.3L Ford engine in the 1.6L block. Each piston has
been fitted with a special top compression ring which is barrel
faced and hard chromed steel. Piston rings two and three are
standard.
A 1984 head gasket that will withstand higher compression
pressures is used to replace the standard gasoline head
gasket. This head gasket uses a stainless steel fire ring and
special backing material.
The base 1.6L camshaft (pink color code) is used in place
of the HO camshaft (yellow color code).
Engine Oil:
A unique engine oil containing a special additive must be
used with methanol-fueled engines. The recommended oil is
marked for methanol engines only.
Ignition
Distributor:
The distributor is a modified, solid-state unit. Its
operation is the same as the standard unit; the advance curves
have been modified. The major difference is less mechanical
advance.
Spark Plugs:
The spark plugs used in the methanol-fueled engine are two
heat ranges colder than the spark plugs in the gasoline powered
1. 6L engine. This is necessary to prevent engine damage due to
preignition.
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-11-
Tests on Aged Catalysts
Baseline (i.e., without a catalyst) FTP and HWY tests were
first run on the Toyota Cressida to compare to the zero-mile
vehicle baseline emissions measured in 1984. The Toyota
Cressida was then used to test the aged catalyst efficiency of
the six catalysts returned from California. FTP and HWY tests
were performed for each catalyst with HC, CO, NOx, MPG, and
aldehydes measured over each test in the sequence.
The need to replace fuel injectors in the Cressida
continued. Table 10 gives a listing of the dates unscheduled,
non-routine maintenance was performed on the Toyota Cressida
for the period July 1, 1984 to September 30, 1987. New
injectors were installed twice during this phase of the project
in July 1984 and again in August 1986.
Bag-by-bag FTP and highway baseline results for the period
August 8, 1986 to September 23, 1987 are presented in Appendix
B. The data for HC in this appendix show that the average
baseline FTP emissions for HC for the tests run November 7 to
14, 1986 are essentially double what they were for the period
August 8 to October 28, 1986. At this point Toyota replaced
the fuel injectors. Baseline HC emissions with this set of
injectors were about the same as those for the period August 8
to October 28, 1986, but CO was lower and NOx higher.
Test results for the aged catalysts are presented in
Tables 11 and 12. Table 11 gives FTP results for the
catalysts; Table 12 gives the HWY results.
Comparison of New and Aged Catalyst Efficiencies
Tables 13 and 14 compare percent conversion efficiency for
the new and aged catalysts for the -FTP and HWY tests
respectively. Because of the shifting of the baseline emission
data, percent conversion gives a better indication . of the
^.erformance of the catalyst than the actual emission levels
achieved by the catalyst. The zero-mileage (i.e., new)
efficiencies in this table are the same as presented previously.
Emission levels as measured on the Cressida are likely to
differ from those in-the Escorts for two reasons:
1. Zngine-out emissions from the Cressida for HC and CO
are low; and
2. The two cars have different engine-out emission and
exhaust gas temperature characteristics.
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-12-
Table 10
Unscheduled Maintenance on the Toyota Cressida*
July l, 1984 to September 30, 1987
Date
Comments
July 3, 1984
November 27, 1984
August 4, 1986
August 18, 1986
August 19, 1986
August 29, 1986
September 10, 1986
November 13, 1986
November 14, 1986
August 8, 1987
September 24, 1987
September 28, 1987
Toyota installed new injectors and a
new pulsating damper valve
New battery installed
New battery installed
Car stalled when put into gear when
started cold for LA-4
Toyota representative observes test
and agrees car needs repair
Toyota installed new fuel injectors
Stalling problem only marginally
improved, caution must be exercised to
keep car from stalling shortly into
the FTP
Several stalls at idle
Engine seems to be running rough at
cruise
Toyota replaced fuel filter and fuel
injectors.
Car stalled 22 times during FTP
preparation.
Car returned to Toyota.
Unscheduled maintenance on the Toyota for the period
February 1, 1984 to June 30, 1984 was previously reported
in Reference 2.
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-13-
Table 11
Aged Oxidation Catalyst FTP Emissions
Catalyst Sample
Formula No.
3Pt:2Pd(20) 4
3Pt:2Pd(20) 5
Pd(20) 6
Pd(20) 1
Pd(20) 1
Test No.
864996*
864998
865000
870165
870167
870177
870451
875295*
879453*
870506*
871339
871340
871341
Date
08/19/86
09/10/86
09/12/86
10/09/86
10/10/86
10/29/86
10/30/86
09/24/87
10/31/86
11/04/86
09/15/87
09/16/87
09/17/87
0
0
0
0
0
0
0
0
0
0
0
0
0
HC
.35
.54
.55
.53
.54
.39
.36
.24
.51
. 47
.40
.36
.41
CO
(g/mi;
3.9
4.8
4.7
5.5
5.5
5.5
5.4
0.49
5.7
7.0
.50
.64
.73
CO 2
)
387
370
369
376
377
377
379
3d7
387
397
383
381
380
0
0
0
0
0
0
0
2
0
0
1
2
2
NOx
.83
.89
.88
.97
.90
.73
.71
.31
.89
.80
.92
.03
. 10
MPG
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
10.
4
9
9
7
6
6
6
6
4
1
6
7
7
HCHO
(jng/mi)
152.8
124.6
83.8
94.5
140.8
366.7
164.4
400.7
187.8
125.4
521.0
611. 5
632.7
Aged Three-Way Catalyst FTP Emissions
Catalyst Sample
Formula No.
3Pt:2Pd(20) 3
Pd(20) 2
Pd(20) 2
Test No.
870169
870171
870535
870527
871334
871335
871336
Date
10/16/86
10/21/86
11/05/86
11/06/86
08/25/87
09/04/87
09/09/87
0
0
0
0
0
0
0
HC
.32
.32
.31
.36
.33
.23
.31
CO
(g/mi;
4.6
4 . 7
5.9
6.9
2.9
2.8
2.9
C02
380
385
391
421
388
391
381
0
0
0
0
1
1
1
NOx
.57
.57
.59
, 54
.36
.59
.29
MPG
10.
10.
10.
9.
10.
10.
10.
6
5
3
5
4
4
6
HCHO
(mg/mi)
68.9
53.6
51 . 5
53.6
156.7
105.8
103 .3
Essentially a void test, not used in data analysis (injectors
changed).
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-14-
Table 12
Aged Oxidation Catalyst HWY Emissions
Catalyst Sample
Formula No.
3Pt:2Pd(20) 4
3Pt:2Pd(20) 5
Pd(20) 6
Pd(20) 1
Test No.
864997*
864999
865001
870166
870168
870438
870452
870454*
870507*
Date
08/10/86
09/10/86
09/12/86
10/09/86
10/10/86
10/29/86
10/30/86
10/31/86
11/04/86
HC
CO
C02
NOx
(g/mi)
0
0
0
0
0
0
0
0
0
.02
. 04
.04
.05
.05
.02
.02
.04
.03
2
5
5
5
5
5
5
6
6
Aged Three-Way Catalyst HWY
Catalyst Sample
Formula No.
3Pt:2Pd(20) 3
Pd(20) 2
Test No.
870170
870172
870536
870528
Date
10/16/86
10/21/86
11/05/86
11/06/86
HC
.9
. r
.1
.8
.4
.2
.4
. 1
.2
334
322
321
334
331
329
333
341
322
0.51
0 .38
0.37
0.42
0.40
0.34
0 .36
0.43
0.34
MPG
12.2
12.5
12.5
12.0
12. 1
12.2
12.1
11.7
12.4
HCHO
(mg/mi)
4.3
4 .9
2.3
3.4
0 .0
4 .7
VOID
3.5
2.3
Emissions
CO
CO z
NOx
(g/mi)
0
0
0
0
.02
.01
. 02
.02
3
2
5
5
. 1
. 6
.2
.6 .
332
333
348
359
0.27
0.27
0.26
0.26
MPG
12.
12.
11.
11.
HCHO
(mg/mi)
2 0 .
2 0.
6 1 .
2 2.
2
0
0
4
Essentially a void test, but used in data analysis (injectors
changed).
-------
-15-
Table 13
Comparison of Percent
New and Aqed Catalyst
Catalyst Formula
Aging and
Testing Mode
Sample Number
3Pt
TWC
3
:2Pd(20
OX
4
Conversion for
s on FTP Test
)
OX
5
TWC
2
Pd(20)
OX
1
OX
6
Efficiency for:
HC
CO
NOx
Aid.
Aged
New
Difference*
Aged
New
Difference
Aged
New
Difference
Aged
New
Difference
78
76
+2
63
68
-5
70
75
-5
82
87
-5
57
73
-16
66
96
-30
51
35
+ 16
67
7
+ 60
63
73
-10
57
96
-39
50
35
+ 15
65
7
+ 58
77
71
-6
62
78
-16
45
85
-40
71
86
-15
70
72
+4
92
92
0
17
36
-19
N/A
17
N/A
82
72
+ 10
73
92
-19
58
36
+22
30
17
+ 13
Table 14
Comparison of Percent Conversion for
New and Aged Catalysts on HWY Test
Catalyst Formula
Efficiency for:
HC
CO
Aged
New
Difference*
Aged
New
Difference
NOx Aged
New
Difference
Aid. Aged
New
Difference
3Pt:2Pd(20)
Aging and Testing Mode TWC
Sample Number 3
OX
97
98
-1
76
88
-12
83
86
-3
100
97
3
90
97
-7
60
99
-39
73
44
29
98
76
22
OX
91
97
-6
52
99
-47
74
44
30
99
76
23
TWC
97
98
-1
69
88
-19
82
97
-15
99
96
3
Pd(20)
OX
OX
95
97
-2
65
99
-34
74
43
+31
99
81
18
97
97
0
70
99
-29
76
43
+23
98
81
17
Difference is aged minus new.
-------
-16-
The percent conversion for the aged catalysts were
determined by calculating the average emissions for each
catalyst on the FTP and HWY tests, and then comparing these
values with the average of the baselines immediately before and
immediately following the tests for that catalyst. For
example, the HWY tests for sample 4 run on September 10 and
September 12, 1986 and compared to the "before" tests run
August 8 and August 12, 1986 and also to the "after" runs on
October 3 and October 8, 1986.
Appendix C shows the effect of the shifts in the baseline
data on the percent conversion date of the aged catalysts. For
some cases, this effect is relatively small. For example,
sample 3 on the FTP test had a percent conversion range for HC
of 76 to 80. For many cases, the effect is much larger (e.g.,
58 to 71 for CO on sample 3 on the FTP test).
The highest tailpipe formaldehyde emission levels (and
lowest percent conversions) occurred on the FTP zero-mileage
runs in the oxidation mode (17 and 7 percent compared to TWC
mode results of 86 and 87 percent for the Pd(20) and
3Pt:2Pd(20) catalysts, respectively).
When operated as oxidation catalysts, the aged Pd(20)
catalysts perform somewhat better than their counterparts with
the 3Pt:2Pd(20) formula, particularly on the FTP. The
differences between the results for the two formulas are
smaller when the catalysts are operated in the TWC mode.
Deterioration Factors
To further compare the catalysts, deterioration factors
were calculated for each of them. Table 15 gives DF* for each
of the six catalysts for HC, CO, NOx, and HCHO, and compares
these values with the actual DF for HC, CO, and NOx for
gasoline-powered light-duty vehicles. In calculating DF*
several assumptuions were made:
1. Differences between the mileage accumulation in
California and the AMA mileage accumulation route were ignored;
2. Maintenance differences were not accounted for;
3. Engine-out emissions were assumed to be constant
over 50,000 miles; and
4. An expodential extrapolation of the form:
Efficiencyt = Efficiency0 EXP (k miles/1000)
was used to calculate emissions at 4,000 and 50,000
miles. This is the same extrapolation method as was used in
reference 4.
-------
-17-
5. Because the exact number of miles each catalyst was
aged was unavailable, the odometer readings when the catalysts
were removed for shipment to Ann Arbor were used as an assumed
number of miles aged. This represents a "best case" scenario.
Under these assumptions, the formula for DF* becomes:
(1 - EFF5o)
DF* =
(1 - EFF4)
Where, EFFSO and EFF4 are the extrapolated catalyst
efficiencies at 4,000 and 50,000 miles, respectively.
A value of "1" was used in Table 15 for those cases where
no deterioration in catalyst efficiency occurred. The data in
this table shows relatively good agreement between catalyst
types and modes. For example the 3Pt:2Pd catalyst, when
operated in Oxcat mode (samples 4 and 5), had DF* values of 2.2
and 2.0 for HC, and 5.3 and 4.6 for CO.
The agreement between DF* and DF for a gasoline car is of
order of magnitude quality. Analysis of this data is
complicated by three factors:
1. The number of samples is small;
2. Little is known about how, when, and where the fleet
vehicles were driven; and
3. The condition of the EPA test vehicle varied greatly
despite the relatively small number of • miles it was driven
during the test period.
Conclusions
After 12,000 to 14,000 miles of fleet use on the road
aging:
1. Both catalyst types tested showed evidence of
deterioration in their ability to convert CO in both three-way
and oxidation modes;
2. There is little evidence of any change in the
ability of either catalyst type to convert HC; and
3. When tested in the three-way mode, both catalyst
types show degradation in their ability to convert NOx.
-------
-18-
Table 15
FTP Deterioration Factors By Catalyst
Sample
Number Formula
3 3Pt:2PD(20)
4
5
2 Pd(20)
1
6
Mode
TWC
OX
ox
TWC
OX
ox
HC
1
2.
2.
1
1 .
1.
2
0
2
3
CO
1 .
5.
4 .
2.
1 .
4 .
NOx
4
3
6
5
0
3
1
1
1
3
1
1
.6
. 1
.4
. 1
HCHO
2
1
1
3
1
.0
. 1
NA
Gasoline car: DF 1.3 1.2 1.1 NA
-------
-19-
References
1. "Low Mileage Catalyst Evaluation With a
Methanol-Fueled Rabbit - Second Interim Report," Wagner, R. and
L. Landman, EPA/OAR/OMS/ECTD/CTAB/84-3, May 1984.
2. "Interim Report on Durability Testing of Low Cost
Catalysts for Methanol-Fueled Vehicles," Wagner, R. and L.
Landman, EPA/OAR/OMS/ECTD/CTAB-84-4, August 1984.
3. "Evaluation of Catalysts for Methanol-Fueled
Vehicles Using a Volkswagen Rabbit Test Vehicle," Piotrowski,
G., J. D. Murrell, and K. Hellman, Proceedings from Methanol:
An Alternate Fuel, ASME Joint Conference on the Introduction
and Development of Methanol as an Alternate Fuel, pp. 90-95,
Columbus, OH, June 1986.
4. "Aftermarket Catalyst Durability Evaluation,"
Bruetsch, R., J. P. Cheng, and K. Hellman, SAE Paper 861555.
-------
A-l
APPENDIX A
Maintenance of Escort/License Plate Number 0868570
Date
06/24/84**
08/09/84
08/22/84
01/14/85
04/05/85
05/22/85
09/11/85
03/12/86
VIN
Odometer
Reading
3144
3493
3632
6222
9233
10058
12087
12493 .8
1FABP137XDW237349*
Comments
Lube, oil, filter
Tow in (mechanical)
Air conditioning water leak
Lube, oil, filter, add antifreeze
Lube, oil, filter, add antifreeze
Tow in (no reason given)
12,000-mile service
Catalyst removed for shipment
Ann Arbor
to
* This vehicle was used to age sample 4, a 3Pt:Pd(20)
catalyst, in oxidation mode.
** First entry in maintenance records.
-------
A-2
APPENDIX A (cont'd)
Maintenance of Escort/License Plate Number 0868571
Date
06/27/83
02/21/84
05/03/84**
12/26/84
03/11/85
04/30/85
07/11/85
08/19/85
10/15/85
11/08/85
11/26/85
03/12/86
VIN
Odometer
Reading
N/A
N/A
3126
6579
9242
9801
9811
10798
12345
12937 ~
N/A
13306.3
1FABP137XDW237350*
Comments
Accepted for delivery
Tow in (no reason given)
Lube and oil change
Lube, oil, filter, checked brakes,
wipers
Add antifreeze
Replace fuel filter
Replace fuel pump
Fix flat tire
12,000-mile service
Detail and check body fenders,
glass wipers, decals, upholstery
Detail exterior.
Catalyst removed for shipment to
Ann Arbor
* This vehicle was used to age sample 1, a Pd(20) catalyst,
in oxidation mode.
** First entry in maintenance records with mileage recorded.
-------
A-3
APPENDIX A (cont'd)
Maintenance of Escort/License Plate Number 0868572
Date
06/20/83
06/27/83
02/16/84
05/24/84
06/12/84
09/24/84
12/17/84
04/11/85
07/27/85
08/06/85
10/11/85
03/12/86 .
VIN
Odometer
Reading
N/A
03
439
2899
3365
4431
6018
9061
11833
11833
13088
14249 . 2
1FABP137XDW237359*
Comments
Predelivery inspection
Accepted for delivery
Inspected
Lube, oil, filter
Inspected
Fix driver ' s door
Lube, oil, filter
Lube, oil, filter, clean air filter
12,000-mile service
Change locks ( key lost)
Replace ash tray
Catalyst removed for shipment to
Ann Arbor
This vehicle was used to age sample 3, a 3Pt:2Pd(20)
catalyst, in three-way mode.
-------
A-4
APPENDIX A (cont'd)
Maintenance of Escort/License Plate Number 0868573
Date
12/14/84**
02/02/85
05/09/85
05/24/85
10/01/85
03/12/86
VIN
Odometer
Reading
6762
7956
9645
10089
N/A '
12732.0
1FABP137XDW237378*
Comments
Add antifreeze
Tow in — out of gas
Lube, oil, filter, change oil filter
Tow in — mechanical
12,000-mile service
Catalyst removed for shipment to
Ann Arbor
* This vehicle was used to age sample 2, a Pd(20) catalyst,
in three-way mode.
** First entry in maintenance records with mileage recorded.
-------
A-5
APPENDIX A (cont'd)
Maintenance of Escort/License Plate Number 0868574
VIN 1FABP137XDW237386*
Date
06/27/83
01/31/84
05/15/84
05/16/84
05/30/84
06/06/84
12/10/84
05/04/85
09/20/85
03/12/86
Odometer
Reading
4
73
3073
3079
9344(?)
N/A
6143
9221
12009
13247.9
Comments
Accepted for delivery
Inspected
Inspected
Lube, oil, filter
4,000-mile service, lube, oil,
filter remove front wheels
Vehicle in accident, but not damaged
Lube, oil, filter, add transmission
fluid, antifreeze
Lube, oil, filter, add antifreeze,
clean air filter
12,000-mile service
Catalyst removed for shipment to
Ann Arbor
This vehicle was used to age sample 6, a Pd(20) catalyst,
in oxidation mode.
-------
A-6
APPENDIX A (cont'd)
Maintenance of Escort/License Plate Number 0868575
Date
06/27/83
04/03/84
04/18/84
05/22/84
06/07/84
07/03/84
02/15/85
07/18/85
08/26/85
08/26/85
09/20/85
03/12/86
VIN
Odometer
Reading
3
N/A
1330
1968
N/A
2545
5823
9331
10171
10171
10172
11809 . 4
1FABP1370DW237405*
Comments
Accepted for delivery
Vehicle misfueled with gasoline;
clean, drain, and flush gasoline
from tank
Fix arm rest
Inspect
Accident — fender, hood, frame
damaged
Lube, oil, filter
Lube, oil, filter, clean air filter,
adjust brakes
Lube, oil, filter
Needs fuel pump
Replace fuel filter
Replace electric fuel pump
Catalyst removed for shipment to
Ann Arbor
This vehicle was used to age sample 5, a 3Pt:2Pd(20)
catalyst, in oxidation mode.
-------
B-l
APPENDIX B
Toyota Cressida Baseline (No Catalyst)
Date
(ODO KM)
8/8/86
(5314.7)
8/12/86
(5376.3)
10/3/86
(5832.7)
10/8/86
(5905.6)
10/23/86
(6273.4)
10/28/86
(6368.5)
11/7/86
(6800.3)
11/13/86
(6862.9)
Test
864992
Bag 1
Bag 2
Bag 3
Average
864994
Bag 1
Bag 2
Bag 3
Average
865003
Bag 1
Bag 2
Bag 3
Average
865005
Bag 1
Bag 2
Bag 3
Average
870173
Bag 1
Bag 2
Bag 3
Average
870175
Bag 1
Bag 2
Bag 3
Average
870529
Bag 1
Bag 2
Bag 3
Average
870531
Bag 1
Bag 2
Bag 3
Average
FTP Results
Odometer
(km)
5314.7
5376.3
5832.7
5905.6
6273.4
6368.5
6800.3
6862 .9
HC
(g/mi)
2.00
1.01
0.85
1.17
2.33
1.09
.96
1.31
2.42
1.06
.97
1.31
. 2.38
1.08
.99
1.32
2.56
1.33
1.20
1.54
2.84
1.42
1.23
1.66
3.31
2.49
1.82
2.46
3.49
2.69
1.81
2.61
CO
(g/mi)
17.7
15.4
13.0
15.2
20.0
17.2
14.8
17.2
14.0
' 10.4
10.1
11.0
14.5
11.3
10.2
11.7
17.2
13.2
12.2
13.7
18.3
13.6
12.3
14.2
24.8
28.2
22. 1
25.8
26.7
28.8
22.6
26.7
C02
(g/mi)
419
351
345
363
432
351
343
366
415
. 340
341
356
418
344
342
358
426
349
346 .
364
421
346
342
360
419
347
342
360
416
342
336
355
NOx
(g/mi)
2.59
1.23
1.98
1.72
2.66
1.27
1.94
1.74
2.74
1.41
2.16
1.89
2.84
1.37
2.11
1.88
2.73
1.44
2.11
1.89
2.71
1.43
2.09
1.87
2.42
1.20
1.86
1.63
2.38
1.09
1.84
1.56
HCHO
(g/mi)
395.7
321.2
261.4
312.4
392.8
374.0
200.9
324.5
435.9
288.1
241.3
305.7
467.5
273.0
246.8
303.9
437.4
315.2
500.6
391. 5
344.0
362.1
235.3
323.0
338.6
436.7
431.9
415.3
504.9
360.1
338.8
393.6
MPG
10.5
10.4
10.9
10.8
10.5
10.6
10.1
10.2
-------
Date
11/14/86
(6924.5)
08/18/87
(7137.0)
08/19/87
(7200.7)
08/20/87
(7211.7)
09/10/87
(7415.9)
09/11/87
09/22/87
(7569.7)
09/23/87
(7592.0)
Test
870533
Bag 1
Bag 2
Bag 3
Average
871328
Bag 1
Bag 2
Bag 3
Average
871330
Bag 1
Bag 2
Bag 3
Average
871332
Bag 1
Bag 2
Bag 3
Average
871337
Bag 1
Bag 2
Bag 3
Average
871338
Bag 1
Bag 2
Bag 3
Average
871342
Bag 1
Bag 2
Bag 3
Average
871343
Bag 1
Bag 2
Bag 3
-.verage
B-2
APPENDIX B (cont'd)
Toyota Cressida Baseline (No Catalyst)
FTP
Odometer
(km) (g
6924.5
3
2
1
2
2
0
1
1
2
1
0
1
2
1
0
1
2
1
0
1
2
0
0
1
2
1
0
1
2
1
0
1
Test
HC
/mi)
.45
.59
.77
.52
.31
.66
.08
.12
.34
.15
.97
.35
.25
.08
.94
.28
.37
.11
.93
. 31
.24
.1
.92
.29
. 17
.13
.94
.29
.24
.15
.95
.32
Results
CO
(g/mi) (
26
28
22
26
7
7
6
7
9
7
6
7
10
7
6
7
10
6
r^
7
10
7
6
7
10
7
5
7
10
7
6
8
.2
.6
.0
.3
.69
.25
.33
.69
.99
.31
.75
.71
.15
.33
.43
.66
.79
.97
.24
.56
. 6
.4
.2
.7
.6
.6
. 6
.9
.3
.9
.6
. 1
CO 2
Lg/mi )
414
341
340
356
404
375
347
373
406
379
348
376
403
373
345
372
398
360'
338
362
397
359
337
361
394
362
331
360
394
362
330
360
NOx
(q/mi)
2
1
1
1
3
3
2
3
3
1
3
2
3
1
2
2
3
1
2
2
3
1
2
2
3
1
2
2
3
1
2
2
.29
.03
.81
.51
.22
.28
.92
. 17
.16
.19
.15
.48
.34
.81
.96
.43
.45
.83
.90
.45
.35
.81
.83
.42
.39
.81
.89
.43
.46
.74
.85
.40
HCHO
(q/mi)
470
379
331
390
590
636
392
560
523
480
380
462
1798
577
399
778
219
307
271
279
235
305
4
209
604
509
445
511
445
448
382
430
.7
.7
.4
.0
.5
.1
.3
.9
.0
.4
.6
.0
.2
. 1
.4
.8
.9
.2
.4
.2
. 6
.3
.4
1
.0
.2
. 6
. 5
.5
.4
.2
.3
MPG
10.2
10.6
10.5
10.6
10.9
10.9
10.9
10.9
-------
Date
08/08/86
08/12/86
10/03/86
10/08/86
10/23/86
10/28/86
11/7/86
11/13/86
11/14/86
08/18/87
08/19/87
08/20/87
B-3
APPENDIX B (cont'd)
Toyota Cressida Baseline (No Catalyst)
Highway Test Results
Test No.
864993
864995
865004
870164
870174
870176
870530
870532
870534
871329
871331
871333
HC
(q/mi)
0.31
0 .37
•0 .47
0 .51
0.61
0. 60
0.88
0.80
0 .91
0 .62
0.61
0 . 59
CO
(q/mi)
14.1
15.7
10.4
11.1
12.9
12.8
22.5
22.5
21.7
5.5
5.9
5.8
CO 2
(q/mi)
318
317
315
316
321
318
322
324
317
292
305
298
NOX
(q/mi)
1.24
1.23
1.54
1.51
1.61
1.54
1.36
1.42
1.28
2.69
2.89
2.81
MPG
12. 1
12.0
12.4
12.3
12.0
12.1
11.4
11.4
11.6
13.6
13\0
13.3
HCHO
(mq/mi)
191.6
181.8
181.8
182.3
203.1
210 .0
251.0
285.2
270.8
52.7
172. 7
N/A
-------
C-l
APPENDIX C
Effect of Baseline Changes On
Percent Conversion On HWY Test
Catalyst
Formula
Pd(20)
Pd(20)
3Pt:2Pd(20
3Pt:2Pd(20
Pd(20)
3Pt:2Pd(20
Sample
Number
1
6
) 4
) 5
2
) 3
Test and
Aqinq Mode
OX
OX
OX
OX
TWC
TWC
Baseline
Comparison
Before*
After**
Before
After
Before
After
Before
After
Before
After
Before
After
Percent Conversion
HC
70
70
77
85
56
59
59
67
77
77
76
80
CO
92
92
61
79
71
58
52
61
63
62
59
67
NOx
17
17
62
54
49
53
50
50
48
42
70
70
Aid.
-141
-25
25
34
67
66
61
67
80
50
80
83
* Compared to baseline tests made before catalyst was tested
** Compared to- baseline tests made after catalyst was tested.
-------
C-2
APPENDIX C (cont'd)
Effect of Baseline Changes On
Percent Conversion On FTP Test
Catalyst Sample
Formula Number
Pd(20) 1
Pd(20) 6
3Pt:2Pd(20) 4
3Pt:2Pd(20) 5
Pd(20) 2
3Pt:2Pd(20) 3
Test and Baseline
Aqinq Mode Comparison
OX Before*
After**
OX Before
After
OX Before
After
OX Before
After
TWC Before
After
TWC Before
After
Percent Conversion
HC
94
96
97
98
89
92
90
92
97
98
97
98
CO
52
72
59
76
66
53
48
56
58
76
74
78
NOx
75
72
78
74
70
75
73
74
84
81
82
83
Aid.
99
99
98
98
98
98
99
99
99
99
100
100
* Compared to baseline tests made before catalyst was tested
** Compared to baseline tests made after catalyst was tested.
------- |