Environmental Protection Technology Series
CHARACTERIZATION OF EXHAUST EMISSIONS
FROM A DUAL CATALYST EQUIPPED
VEHICLE
Environmental Sciences Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
Tha five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
Tnis report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
en/ironmental degradation from point and non-point sources of pollution. This
wcrk provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
Tnis document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-77-068
April 1977
CHARACTERIZATION OF EXHAUST EMISSIONS
FROM A DUAL CATALYST EQUIPPED VEHICLE
by
Peter A. Gabele, James N. Braddock, Frank M. Black,
Fred D. Stump, and Roy B. Zweidinger
Emissions Measurement and Characterization Division
Environmental Sciences Research Laboratory
Research Trianlge Park, N.C. 27711
ENVIRONMENTAL SCIENCES RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
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DISCLAIMER
This report has been reviewed by the Environmental Science Research Lab-
oratory, U. S. Environmental Protection Agency, and approved for publi-
cation. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
n
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ABSTRACT
A test program was initiated to characterize exhaust gas emissions
from an automobile equipped with a dual catalyst system. The dual catalyst
system was designed by Gould, Inc. to reduce emissions of engine exhaust
hydrocarbons, carbon monoxide, and nitrogen oxides. It basically consists
of two catalysts in series: a nickel-copper alloy reduction catalyst to
control carbon monoxide and hydrocarbon emissions.
The test vehicle, an AMC Hornet having a 232 CID six cylinder engine,
was tested over the Federal Test Procedure, the Highway Fuel Economy Test,
and the Sulfate Emission Test. In addition to the regulated gaseous emis-
sions, sulfur dioxide, sulfuric acid, hydrogen cyanide, nickel carbonyl,
carbonyl sulfide, aldehydes, and detailed hydrocarbon emissions were
sampled and analyzed. A brief discussion of each method used to sample
and analyze the non-regulated pollutants in included.
Results indicate that (1) sulfate emissions from the dual catalyst
car were comparable to those from production catalyst vehicles equipped
with air pumps, (2) hydrocarbon emissions were of low reactivity relative
to other vehicles, and (3) nickel emissions were quite high. With regard
to the nickel emissions, the forms in which this element are emitted are
not known nor 1s the extent of nickel carbonyl emissions known.
iii
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ACKNOWLEDGEMENTS
The authors would like to acknowledge the consistent support of the
Northrop Services, Inc. chassis dynamometer team: Roy Carlson, "Boone"
Peyton, Jerry Faircloth, and "Butch" Crews. Their hard work is greatly
appreciated and their positive attitude makes working with them just
that much more enjoyable.
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SECTION 1
INTRODUCTION
In an effort to comply with increasingly stringent emission standards.
prototype automobiles have been equipped with different types of emissior
control equipment. While many approaches show promise in reducing the
emissions of the regulated pollutants (HC, CO, and NO.), these control
systems should be examined for potential emissions of other harmful yet
non-regulated gaseous and particulate pollutants.
One such control system which has shown promise in reducing regulated
gaseous emissions from automobiles is the Gould dual catalyst system
depicted in Figure 1. This system consists of a nickel-copper alloy
NET RICH
CARBURETOR
NICKEL
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reduction catalyst followed in series by a platinum-palladium oxidation
catalyst. The exhaust gases, containing hydrocarbons, carbon monoxide,
and oxides of nitrogen, flow from the exhaust manifold into the reduction
catalyst. In the reduction catalyst, under net reducing conditions,
excess oxides of nitrogen are catalytically reduced forming molecular
nitrogen. After exiting the reduction catalyst, the exhaust gases are
mixed with injection air from the air pump. The air injection rate is
carefully controlled to maintain a net oxidizing condition favorable for
the catalytic oxidation of excess hydrocarbons and carbon monoxide. Pro-
ceeding into the oxidation catalyst, the hydrocarbon and carbon monoxide
exhaust gases are heterogeneously oxidized to water vapor [^(g)] and
carbon dioxide [C02J. Small, carefully controlled quantities of air are
likewise injected before the reduction catalyst to aid in system warm-
up and in temperature maintenance. Carburetion is adjusted to control
air-fuel ratios to 13.82 t 0.18. Air-fuel ratio control to just slightly
rich of stoichiometric is desired to provide a reducing atmosphere for
the NOX reduction catalyst while avoiding the overly rich mixture operation
associated with poor fuel economy (1).
This paper examines the emissions from a Gould dual catalyst equipped
automobile. In addition to the regulated emissions, non-regulated pol-
lutants such as sulfuric acid, S02, nickel carbonyl, carbonyl sulfide
(COS), aldehydes, hydrogen sulfide (H?S), and hydrogen cyanide (HCN) were
examined. Detailed hydrocarbon and aldehyde emissions measurements were
also performed to evaluate the reactivity of those hydrocarbons being
emitted. The methods employed for sampling and analysis of each of the
non-regulated pollutants are also discussed.
This study represents a preliminary investigation of the emission
patterns obtained from one dual bed catalyst prototype car. Further
work to investigate the potential for environmental harm from such vehi-
cles will be undertaken in the near future.
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SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
The following conclusions have been made based on the experimental
test program carried out on the Gould dual catalyst car:
1. Sulfate emissions measured over the Sulfate Emissions Test were
comparable to those measured on production catalyst vehicles
equipped with air pumps. Such vehicles represent the highest
sulfate emitters presently in use.
2. Detailed hydrocarbon analyses demonstrated that hydrocarbon
emissions from the Gould car were of a low reactivity relative
to other vehicles tested at this facility.
3. Nickel emissions were significantly high, especially those measured
on the first day of testing.
Although initial tests indicate the possible presence of nickel
carbonyl in the dual catalyst vehicle's exhaust, some degree of analytical
refinement coupled with further testing 1s required before any definite
conclusions can be drawn regarding the emission of this compound.
Immediate work should be directed towards the attainment of a firm
conclusion with regard to this possible emission.
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SECTION 3
EXPERIMENTAL PROCEDURES
EXPERIMENTAL EQUIPMENT
The dual catalyst system tested was installed on an AMC Hornet
having a 232 CID six cylinder engine. A detailed description of the
test vehicle is given in Appendix A. Upon arrival at this facility the
odometer registered 12,500 miles. The observed spark timing was 5
degrees BTDC. Prior to dynamometer testing, the car was driven 500
miles over a mileage accumulation route for conditioning on the test
fuel.
The "Raleigh Road Route", as the mileage accumulation route is
termed, begins at the test laboratory, extends through the city of
Raleigh, arid returns to the test laboratory through the city of Durham.
It is 51.8 miles long and has an averaged speed of 35 miles per hour.
The route involves 20.7 expressway miles, 7.8 "suburban" miles, 23.3
miles on city streets, and an overall average of 0.62 stops per mile
varying somewhat with traffic conditions. Considering the usual estimate
of a 45 percent highway to 55 percent urban split for all U.S. driving,
this route appears to be a reasonable representative mileage accumulation
schedule. The schedule is repeated four times per day with half-hour
cool-down periods between routes. Thus, the 500 miles were accumulated
in 2-1/2 days.
A .030 weight percent sulfur fuel was used throughout the experiments.
This sulfur level was attained by doping an unleaded test fuel with
reagent grade Thiophene, C^S. Appendix B lists the fuel properties
of the fuel used throughout the tests.
The experimental study was carried out in an automobile emissions
laboratory equipped with a Clayton CT-50 water brake chassis dynamometer.
Vehicle exhaust emissions were sampled for both particulate and gaseous
pollutants in a combined dilution tunnel-constant volume sampler (CVS)
arrangement: (Figure 2). The diluent plus exhaust gas flow rate through
the system was maintained at 407 ACFM. The participate matter was
sampled isokinetically in the dilution tunnel utilizing a four probe
rake. The particles were collected on 47 mm filters in standard 47mm
filter holcers. Routine gas (HC, CO, C02, and NOX) sampling and analysis
was carriec. out in accordance with specifications given in the Federal
Register.(2!) Chassis dynamometer operation was also conducted in accordance
with these specifications.
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PARTICULATE
ANALYSIS:
FOUR 1-in. OIAM.
PROBES
AIR
IN
2ft. -»
ABSOLUTE
FILTER
•12ft
TO
VACUUM
SOURCE
/a'V"
™* ^
It-w-OI/L
GAS ANALYSIS:
HC. CO, NOX,
C02.COS
S02
ANALYSIS
ft
iti
ORIFICE MIXING PLATE
4 • in. OIA.
CVS
CONSTANT
VOLUME
SAMPLER
r
EXHAUST PIPE
¥
100°C
HEATED
SAMPLE
APPARATUS
EXHAUST
OUT
HCN
ANALYSIS
ALDEHYDE
ANALYSIS
Figure 2. Sampling system.
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ANALYSIS OF NON-REGULATED POLLUTANTS
Detailed hydrocarbon analyses were performed using the chromatographic
procedures of Dimitriades and Seizinger.(S) These procedures permit
quantification in excess of 95 percent of the total hydrocarbon being
emitted. Fifty seven different chromatographic peaks are reported
detailing the C-, through C,Q hydrocarbons. A computer system interfaced
to the gas chromatograph facilitates rapid identification and quantification
of the pea
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dinitropiienylhydrazine (DNPH) frrHCl. Carbpnyls present in the sample
stream react with the absorbing reagent forming soluble and insoluble
hydrazone derivatives which are removed by filtration.and extraction
techniques. Aldehyde characterization is then completed using a. single
gas chromatographic analysis.
Hydrogen cyanide (HCN) was measured in the dilute exhaust by passing
the gaseous samples through series impingers containing a 0.3N NaOH
Epstein's procedure (6) using a Techicon Autoanalyzer integrated with
a Varian 635D spectophotometer having a 1.0 cm automatic flow cell.
Wet chemical techniques were used to determine H2S emission over the
75 FTP runs. Bubbler samples obtained from CVS dilute exhaust were
collected in impingers containing 15 cc of absorbing solution (zinc
hydroxide stabilized with ammonium sulfate and glycerin) and analyzed by
the methylene blue method (7}. Standards prepared from permeation tubes
were used to qualify the sample collection method (8). Absorbing solutions
containing known amounts of H?S showed some loss on exposure to auto
exhaust. An effective detection limit of 0.6 y H2S per sample was
Indicated.
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SECTION 4
RESULTS AND DISCUSSION
ROUTJN.E GASEOUS AND PARTICULATE DATA
Routine gaseous and particulate sampling and analyses were conducted
during an initial test series performed on the dual catalyst car. Runs
within these series were sequenced over two days of testing. The daily
test sequence was as follows: one 75 Federal Test Procedure (FTP), two
Sulfate Emission Tests (SET), two Highway Fuel Economy Tests (HWFET),
and two more SET'S.
Subsecsuent FTP'S were run to obtain additional information about
detailed hydrocarbons, HpS, HCN, COS, aldehydes, and nickel carbonyls.
Also, two final FTP runs were obtained for routine gaseous analysis when
it was discovered that the inertia settings on previous runs had been
set 500 pounds too high. Such an error is expected to have affected the
gaseous emissions data and as it turned out, the HC, CO, and NOx emissions
were about 8, 47, and 26 percent lower, respectively. The fuel economy
was found to be only about three percent higher.
The complete gaseous emissions data is presented in Tables 1 and 2.
Run numbers over 5378 were conducted following the initial two day_test
program described above. The average values are indicated by the x
symbol and are shown at the bottom of each data set. The data set
labeled "3500 Ib. inertia load" covers those tests for which the inertia
load was set as prescribed in the Federal Register.
EPA Ann Arbor had previously tested this same car for gaseous and
sulfate emissions. Their HC, CO, and NOx emission rate measurements
were 0.18, 2.74, and 0.34 gm/Km, respectively. These HC and NOx values
compare fairly well with the 0.14 and 0.37 gm/Km levels reported here.
Their CO level is closer to the 1.41 gm/Km. level meausred at this lab
while testing at the heavier inertia loadings. The low CO measurements
recorded at the correct inertia setting should be viewed with some
caution because only two data points were obtained at this setting.
The oxidation catalyst appeared very active as evidenced by the
extremely low CO and HC emission rates. The reduction catalyst was
effective in reducing the NOx emissions to about 0.37 grams per kilometer
over the FTP runs with the 3500 Ib. inertia loading. Even at higher
inertia loadings NOx emissions were quite low, the average being about
0.50 gm/Km.
8
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Table 3 lists the sulfur dioxide, sulfate and particulate emission
rates from each of the tests conducted. Of primary interest are the
sulfate -results from the SET runs. High sulfate emissions were expected
because of high oxidation catalyst activity in conjunction, with high Oj?
levels in the exhaust preceding the catalyst.. The average sulfate emission
rate for the SET was 23.8 mg/Km. with the sulfate material comprising
approximately 51 percent of the total particulate matter emitted. EPA-
Ann Arbor has reported an SET sulfate emission rate of 22.5 mg/Km. for this
same vehicle. This sulfate emission rate is greater than that of the
average production catalyst vehicle not equipped with an air pump.
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TABLE 1. GASEOUS EMISSION RESULTS
FTP GASEOUS EMISSIONS
(gm/km)
4000 tb. INERTIA LOAD
RUN*
5365
5372
5404
5407
5408
5411
5432
5433
X
HC
0.162
0.158
0.161
0.189
0.124
0.149
0.158
0.155
0.157
(0.251 gm/mi)
CO
1.710
1.282
1.519
1.915
1.230
1.014
1.223
1.406
1.413
(2.261 gm/mi)
NOX
0.485
0.534
0.439
0.509
0.577
0.470
0.504
0.512
0.504
) (0.8B6 gm/mi)
km/I
6.52
6.27
6.31
6.12
6.35
6.56
6.11
6.77
6.37
(15.06 mpg)
3500 Ib., INERTIA LOAD
5434
5435
X
0.149
0.139
0.144
(0.230 gm/mi)
0.816
0.681
0.749
(1.1 98 gm/mi)
0.403
0.345
0.374
(0.598 gm/mi)
6.73
6.33
6.53
(15.44 mpg)
10
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TABLE 2. GASEOUS EMISSION RESULTS
HWFET GASEOUS EMISSIONS
(gm/km)
RUN*
5368
6369
6375
5376
X
HC
0.099
0.134
0.069
0.096
0.098
(0.1 56 gin/mi)
CO
0.091
0.199
0.090
0.090
0.118
(0.188gm/mi)
NOX
0.135
0.146
0.107
0.143
0.133
(0.213 gm/mi)
km/I
9.09
9.16
9.55
9.22
9.25
(21.87 mpg)
SET GASEOUS EMISSIONS (gm/km)
5366
5367
5370
5371
5373
5374
5377
5378
X
0.066
0.091
0.204
0.068
0.146
0.064
0.064
0.084
0.098
(0.157 |m/mi)
0.126
0.126
0.126
0.126
0.126
'
'• • •
0.136
0.128
(0.204 |m/mi)
0.351
0.176
0204
0.223
0.524
0.554
0.431
0.361
0.353
(0.665 mi/mi)
8.48
8.44
8.32
8.32
8.84
8.57
8.34
7.69
8.31
(11.80 mp|)
n
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ro
TABLE 3. SO2, SO4, AND PARTICULATE MATTER EMISSIONS RESULTS
FTP EMISSIONS
RUN#
5365
5372
X
S02
gm/km
0.011
0.021
0.016
(0.026 gm/mi)
FUELS
ASS02
%
15.7
30.4
23.0
PARTICULATE
me/km
11.1
28.8
19.9
(31.9 mg/mi)
S04
mg/km
2.1
12.6
7.3
(1 1 .7 mg/mi)
SO/t/PARTICULATE
%
18.6
43.6
31.1
FUELS
ASSO/i
2.0
11.9
6.9
TOTAL SULFUR
BAUANHF
17.7
42.3
30.0
HWFET EMISSIONS
SET EMISSIONS
5368
5369
5375
5376
X
0.026
0.029
0.025
0.025
0.026
(0.042 gm/mi)
55.9
60.7
54.1
52.6
55.8
32.4
29.9
49.3
5.1
40.6
(65.0 mg/mi)
16.8
15.4
23.9
23.9
20.0
(32.0 mg/mi)
51.7
51.4
48.5
47.5
49.8
23.5
21.3
34.5
34.0
28.3
79.4
82.0
88.6
86.6
84.1
5366
5367
5370
5371
5373
5374
5377
5378
X
0.031
0.019
0.028
0.031
0.023
0.019
0.020
0.023
0.024
(0.039 gm/mi)
60.5
37.1
53.3
57.2
45.6
37.8
38.1
40.2
46.2
23.8
29.9
34.3
40.6
72.3
70.0
61.2
51.3
47.9
(76.7 mg/mi)
14.5
15.8
17.7
20.8
33.6
33.9
29.1
24.7
23.8
(38.0 mg/mi)
60.9
52.8
51.7
51.1
46.4
48.3
47.6
48.2
50.9
18.6
20.3
22.2
28.0
45.3
44.0
36.9
28.6
30.5
79.1
57.4
75.5
85.1
90.9
81.8
75.0
E8.8
76.7
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TABLE 4. ELEMENTAL ANALYSIS
OF PARTICULATE MATTER
TEST CYCLE
FTP
SET
%C«
3.2
3.9
C-mg/km
(mo/mi)
0.64
(1.02)
1.61
(2.67)
XH*
4.8
2.0
H-mg/km
(mo/mi)
0.98
(1.53)
0.81
(1.23)
•VALUES REPRESENT THE PERCENTAGE OF COMPONENT
CONCENTRATION WITHIN THE PARTICULATE MATTER
SAMPLED.
The quantity of carbonaceous material contained within the particulate
matter examined was quite small. Table 4 shows the results of combustion
analyses for percent carbon and hydrogen content and the low carbon
percentages are apparent. At first glance the hydrogen content might
appear high, but these values reflect the amount of water in combination
with high levels of sulfuric acid present.
13
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DETAILED HYDROCARBON AND ALDEHYDE EMISSIONS
The detailed hydrocarbon emission rates for the FTP are given in
Table 5. The values reported are the means of three tests. The gm/Km
emission rates for each hydrocarbon are calculated utilizing the actual
density of each specific compound (i.e. methane: 18.86 gm/cu. ft.,
ethylene: 16.51 gm/cu ft., acetylene: 15.33 gm/cu. ft., etc) rather than
16.33 gm. cu. ft. average density specified in the Federal Register.
The Federe.l Register value is based on an average hydrocarbon molecule
having a hydrogen to carbon ratio of 1.85. However, with detailed
chromatographic information available, the actual hydrocarbon molecule
is known and the density for each respective compound can be accurately
calculated.
To permit discussion of the photochemical reactivity of the emissions,
the compounds were subdivided into four basic reactivity groupings.
These groupings have been suggested by Dimitriades (9) with relative
reactivity ratings as follows:
Class Relative Molar Reactivity
Rating (normalized to Class I)
I. (Nonreactive) 1.0
Ci-C3 paraffins,
acetylene, benzene
II. (Reactive) 6.5
C^+ paraffins
III. (Reactive) 9.7
aromatics less
benzene
IV. (Reactive) 14.3
olefinics
For this vehicle 29.5 percent of the total mass emitted was Class 1,
49.6 percent Class II, 13.3 percent Class III, and 7.6 percent Class.IV.
This compares very favorably with other vehicles previously tested. (1.0)
Table 6 shows the comparison with several other vehicles and emission
control systems. It is apparent that the relative abundance of olefinic
and aromatic hydrocarbons is significantly less. Also of significance is
the finding that of the total hydrocarbon mass emitted, 24.8 percent
was methane.
14
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TABLE 5. FTP DETAILED HYDROCARBON EMISSIONS
Peak No
1
2
3
4
5
6,
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50 -
51
52
53
54
55
56
57
Compound
Methane
Ethyl ene
Ethane
Acetylene
Propylene; propane
Propadiene
Methyl acetylene
Isobutane
Butene 1 ; isobutylene
N-butane; 1, 3-butadiene
Trans-2-butene
Cis-2-butene
3-methyl-l-butene
Isopentane
Pentene-1
N-pentane; 2 -methyl -1-butene
Trans-2-pentene
Cis-2-pentene
2-methvl-2-butene
Cyclopentane ;3-methyl -1 -pentene
2. 3-dimethyl butane
2-methylpentane; 2, 3 -dimeth -1-butene
3-methvlpentane
1 -hexene ;2-ethvl -1 -butene
N-hexane; cis-3-hexene
2 methyl -2-pentene
Methyl cyclopentane; 3r-methtrans-2-pentene
2.4-dimethvlpentane
Methylcyclopentene
Benzene, cvclohexane
Cvclohexene; 2,3-dimethylpentane; 2-methylhexane
3-methylhexane
Iso octane
N-heptane
Methylcyclohexance
2,4 and 2,5-dimethylhexane
2,3j4-trimethylpentane
2 ,3 ,3-trimethyl pentane
Toluene; 2,3-dimeth.ylhexane
2-methyl heptane
3-methyl heptane
2J2J5-tri methyl hexane
N-octane
2j3,5-trimethylhexane
2 ,4-di methyl heptane
2,5 and 3, 5-dimethyl heptane
Ethyl benzene; 2, 3-dimethyl heptane
P-xylene; m-xylene . 4-methyloctane
0-xylene; unk Cq paraffin
Nonane
N-propyl benzene
1 -methyl 3-ethyl -benzene; unk Cm paraffin
1 -methyl -2 rethyl benzene; unk C]p paraffin
Mesitylene
1 ,2 ,4-trimethyl benzene
.Secbutyl benzene; n-decane
Unknowrs
ym/ IMII.
.0484
.0069
.0069
.0024
.0030
.0002
ND
.0009
.0019
.0149
.0009
.0002
.0001
.0175
NO
.0121
.0004
.0004
.0064
.0185
.0014
.0005
.0002
.0006
.0002
.0005
.0002
ND
.0022
.0061
.0014
.0110
.0014
.0007
.0025
.0012
ND
.0107
.0018
.0015
.0002
.0014
.0001
.0001
.0002
.0006
.0014
.0008
.0001
.0001
.0005
ND
ND
ND
.0001
.0019
.1953 ± .0184
(.3125 gin/mi)
TOTAL
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TABLE 6. COMPARISON OF EXHAUST HC REACTIVITIES
VEHICLE
AMC HORNET
PROTOTYPE
1975
CHRYSLEF!
IMPERIAL
PROTOTYPE
440 CID
1975 FORD
GRANADA
302 CIO
1975 CHEV.
IMPALA
350 CID
1975 PLY.
FURY
318 CID
CONTROL
SYSTEM
DUAL CATALYST
W/ AIR PUMP
ELECTRONIC LEAN
BURN
SINGLE MATTHEY-
BISHOP OX-CAT.
W/ AIR PUMP
AC OX-CAT.
UOP OX-CAT.
HC*
gm/km
(gm/mi)
0.19
(0.31)
0.23
(0.36)
0.34
(0.55)
0.16
(0.25)
0.31
(0.49)
PERCENTAGE OF TOTAL
CLASS
1
29.5
18.8
21.7
22.1
13.8
CLASS
II
49.6
23.8
39.1
39.2
50.9
CLASS
III
7.6
17.8
18.8
18.2
18.0
CLASS
IV
13.3
39.6
20.4
20.4
17.3
"BASED ON SUMMATION OF DETAILED HYDROCARBON EMISSION RATES.
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Aldehyde emission results are listed in Table 7. The present GC
analytical system is incapable of separating acetone, acrolein, and
propionaldehyde because all have approximately the same retention times,
therefore, these emissions are all calculated .on the basis of an acetone
emission. Sampling for aldehydes was conducted over three FTP'S with
the mean emission of total aldehydes being .01725 gm/Km. This value
compares favorably with prototype lean burn, catalyst, and CVCC vehicles
tested to date. Aldehyde emissions from these vehicles are also included
in Table 7 for comparison purposes.
Of interest is the apparent trend in aldehyde emissions over the
three tests conducted. Although formaldehyde emissions remain essentially
constant over the tests, the other aldehyde emissions are seen to decrease.
No explanation 1s available for this trend and 1t is unfortunate that
further testing to elicit some clarification could not have been completed
because of time restrictions. ,
EMISSIONS OF COS, HgS, N1(CO)4, AND HCN
Three separate FTP's for COS collection were run on the dual catalyst
car and results Indicate that COS was present at concentrations not
greater than 5 ppb. Most of the COS present occurred during the cold
start mode (bag T) of the FTP. It was found that COS did not react with
auto exhaust in dilution tunnel Injection experiments in which equal
concentrations of COS injected Into the tunnel both with and without
auto exhaust present gave identical COS recoveries from bag samples. The
COS concentration in the bag samples remained stable for at least 24
hours.
No H2S was detected in the CVS diluted exhaust gas in any of the
FTP runs conducted. H,S detection limits of 0.6 jag per sample correspond
to a concentration of 34 ppb during Bag 1 of the FTP. Bag 1 is most
crucial from the standpoint of H£S formation in catalyst vehicles because
of the lower temperature and richer operating conditions associated with
cold starts and warmups.
Analyses for nickel carbonyl were performed utilizing a gas chromato-
graphic separation and electron capture detection. Results indicate
that a strong electron-absorbing species is present at a retention time
very close to that of nickel carbonyl. However, additional experimentation
needs to be performed before it can be stated conclusively that this
component is in fact nickel carbonyl. It is highly possible that an
interference problem exists from some unknown component.
Collection and measurement for HCN was conducted over two FTP .
cycles. The HCN emissions which were measured over each test are shown
in Table 8. HCN emissions, from the Chryslers and Honda CVCC are also
included for comparison purposes and these test results indicate that
HCN emissions from the dual catalyst vehicle are lower.
17
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TABLE 7. FTP ALDEHYDE EMISSIONS - mg/km
VEHICLE/
RUN*
AMC HORNET
DUAL CATALYST:
5404
5407
5408
X mg/km
(mg/mi)
1975 CHRYSLER
440 CID, LEAN
BURN
1975 HONDA
cvcc
1975 FORD W/
OX-CAT.
FORM-
ALDEHYDE
4.51
4.11
4.76
4.46
( 7.13)
25.88
(41.40)
10.61
(16.97)
19.56
(31.30)
ACET-
ALDEHYDE
3.28
1.76
0.91
1.98
( 3.17)
7.94
(12.70)
3.18
( 5.08)
4.38
{ 7.00)
ACETONE/
ACROLEIN/
PROPION-
ALDEHYDE
15.64
6.56
3.76
8.66
(13.85)
7.06
(11.30)
3.27
( 5.23)
11.00
(17.61)
CROTON
ALDEHYDE
0.15
ND
ND
0.15
(0.24)
2.30
(3.68)
0.72
(1.16)
ND
HEXAN-
ALDEHYDE
0.54
ND
0.18
0.36
(0.58)
0.16
(0.26)
0.16
(0.26)
4.13
(6.59)
BENZ-
ALDEHYDE
2.93
1.54
1.22
1.89
(3.03)
5.36
(8.57)
1.96
(3.14)
5.75
(9.21)
TOTAL
27.04
13.98
10.83
17.25
(27.6 )
46.13
(73.80)
19.90
(31.84)
43.38
(69.40)
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TABLES. FTP HYDROGEN
CYANIDE EMISSIONS
VEHICLE/
RUN#
AMC HORNET
DUAL CATALYST:
5432
5435
X
1975 CHRYSLER
441 CIO LEAH
BURN -242
1975 CHRYSLER
440 CID LEAN
BURN -251
1975 HONDA
CVCC
HCN EMISSION
rag/km
(me/mi)
3.96
( 6.33)
1.59
( 2.55)
2.71
(4.44)
US
(10.20)
7.13
(1140)
7.19
(11.51)
X-RAY FLUORESCENCE ANALYSIS
X-ray fluorescence analysis of participate samples was performed to
determine the extent of trace element emissions. The summarized results
are listed according to test cycle 1n Table 9. The filters from which this
data was extracted were collected during each of the tests conducted over the
first two days of testing. The only elements having significant emission
rates were nickel, sulfur, and Iron. When it is assumed that the sulfur
is emitted as H^SO^'SHgO and the iron as FegC^, the total mass of particulate
matter emitted over each of the three test cycles (Table 3) can nearly
be accounted for.
Nickel emissions were prominent in the FTP runs. On the very
first FTP the nickel emission rate 4.38 mg/Km., an emission equal to 40
percent of the total particulate matter emitted. On later tests the
rate was observed to trail off. Nonetheless, these rates are much
higher than those observed when testing other vehicles at this facility
and it would appear that the nickel alloy reduction catalyst is the
source of this emission.
Iron emissions were only of significance over the FTP.runs. High
iron oxide emissions occur during the FTP because exhaust gas fluctuations
are more severe than during the other test cycles. This sort of findina
is consistent with data reported on catalyst car emissions by Braddock (11)
19
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TABLE 9.
X-RAY ANALYSIS SUMMARY
ELEMENT
Pb
Si
Al
S
Cu
Ni
Fe
Cl
FTPl
mg/km
(nig/mi)
0.11
(0.18)
0.08
(0.12)
0.03
(0.05)
2.54
(4.07)
0.08
(0.12)
2.58
(4.12)
0.35
(0.56)
0.02
(0.03)
SET2
mg/km
(mg/mi)
0.04
(0.07)
0.02
(0.03)
0.01
(0.01)
7.09
(11.35)
0.01
(0.02)
0.31
(0.50)
0.04
(0.07)
NO
HWFET3
mg/km
(mg/mi)
0.02
(0.03)
0.02
(0.03)
0.01
(0.01)
6.26
(10.01)
0.01
(0.01)
0.17
(0.27)
0.02
(0.03)
ND
-------
REFERENCES
1. Bernstein, L.S., Lang, R.J., Lunt, R.S., and Musser, 6.S., "Nickel-
Copper Alloy NOV Reduction Catalysts for Dual Catalyst Systems,"
SAE Paper 730567, May 1973.
2. Federal Register, Vol. 37, No. 221, November, 1972.
3. Dimitriades, B., and Swizinger, D.E., Environ. Sci., and Technol.,
5_, 223 (1971).
4. Wagroan, J., "Chemical Composition of Atmospheric Aerosol Pollutants
by High Resolution X-Ray Fluorescence Spectrometry." Colloid
and Interface Science, Vol. II, Academic Press, New York, N. Y., 1976.
5. Sunderman, F. W., Arch, Env1 ron. Heal th, 16., 836 (1968).
6. Epstein, J., Analytical Chemistry, 1£. 272 (1947).
7. Gustaffson, L., Talanta, 4, 227 (1960).
8. O'Keeffe, A.E. and Ortman, 6.C., Analytical Chemistry, 38, 760
(1966). ~~
9. Dimitriades, B., "The Concept of Reactivity and Its Possible
Application in Control." Paper presented at Proceedings of the
Solvent Reactivity Conference, EPA, Research Triangle Park, N.C.
EPA Report No. EPA-650/3-74-101, November, 1974.
10. Black, F.M., and Bradow, R.L., "Patterns of Hydrocarbon Emissions
from 1975 Production Cars." SAE Paper 750681, June 1975.
11. Braddock, J., "Gaseous, Particulate, and Sulfur Related Emissions
from Catalyst and Non-catalyst Vehicles." EPA In-house report,
April 1977.
21
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APPENDIX A
Test Vehicle Description
Prototype AMC Hornet Dual Catalyst Car
Engine
type in-line 6 cyl., spark ignition
bore x stroke, cm x cm (in x in) .... 9.525 x 9.893 (3.75 x 3.89)
displacement, cc (in ) ......... 4228 (258)
compression ratio 7.95:1
maximum power @ rpm, Kw (Hp) 74.57 (100) @ 3600 rpm.
fuel metering gasoline
Drive Train
transmission automatic
final drive ratio 3.08
Chassis
type front engine, rear wheel drive
tire size. . 695 x 14
inertia weight 3500 Ibs.
passenger capacity 5
Emission Control System
basic type Engelhard II B oxidation
catalyst, Gould GEM 68
reduction catalyst, air pump,
and EGR.
22
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APPENDIX B
Unleaded Gasoline Analysis
Research Octane Number . 93.2
Motor Octane Number . 84.7
Reid Vapor Pressure, psia 10.2
Distillation. AST, D-86. °F
IBP . 90
10% . 124
50% 203
90% . 290
EP 372
FIA Analysis
Aromatics % . . 24.0
Olefins % 8.3
Paraffins % . .. . 67.7
API Gravity @ 60°F 61.6
Weight % C . 85.26
Weight % H 14.01
Weight % S . , 0.020
Lead, gm/gallon 00004
23
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1.
4.
7.
9.
REPORT NO. 2. .
EPA-600/2-77-B68
TITLE AND SUBTITLE
CHARACTERIZATION OF EXHAUST EMISSIONS FROM A
DUAL CATALYST EQUIPPED VEHICLE
Peter A. Gabele, James N. Braddock, Frank M. Black,
Fred D. Stump, and Roy B. Zweidinger
PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Sciences Research Laboratory
Office of Research and Development
U. S. Environmental Protection Agency
Research Triangle Park, N. C. 27711
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Sciences Research Laboratory - RTP, NC
Office of Research and Development
U. S. Environmental Protection Agency
Research Triangle Park, N. C. 27711
3. RECIPIENT'S ACC£SSION>NO.
5. REPORT DATE
April 1977
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
1AD605
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
In-house 7/75 - 7/76
14. SPONSORING AGENCY CODE
EPA/600/09
15. SUPPLEMENTARY NOTES
IB. ABSTRACT A tes£ program was initiated to characterize exhaust gas emissions from
an automobile equipped with a dual catalyst system. The dual catalyst system
was designed by Gould, Inc. to reduce emissions of engine exhaust hydrocarbons,
carbon monoxide, and nitrogen oxides. It basically consists of two catalysts in
series: a nickel-copper alloy reduction catalyst to control nitrogen oxide
emissions, and a platinum-palladium oxidation catalyst to control carbon monoxide
and hydrocarbon emissions.
The test vehicle, an AMC Hornet having a 232 CID six cylinder engine, was
tested over the Federal Test Procedure, the Highway Fuel Economy Test, and the
Sulfate Emission Test. In addition to the regulated gaseous emissions, sulfur
dioxide, sulfuric acid, hydrogen cyanide, nickel carbonyl, carbonyl sulfide,
aldehydes and detailed hydrocarbon emissions were sampled and analyzed. A
brief discussion of each method used to sample and analyze the non-regulated
pollutants is included. .
Results indicate that (1) sulfate emissions from the dual catalyst car
were comparable to those from production catalyst vehicles equipped with air
pumps, (2) hydrocarbon emissions were of low reactivity relative to other vehicles,
and (3) nickel emissions were quite high. With regard to the nickel emissions,
the forms in which this element are emitted are not known nor is the extent of
nirlfel rarhnnvl omi«;<:innc known
17
a.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS b. IDENTIFIERS/OPEN ENDED TERMS
*Air pollution
Automobiles
*Exhaust emissions
*Catalytic converters
13
. DISTRIBUTION STATEMENT • 19. SECURITY CLASS (This Report)
UNCLASSIFIED
RELEASE TO PUBLIC . 20. SECURITY CLASS (TMspage)
UNCLASSIFIED
c. COS ATI Field/Group
13B
13F
21B
07A
21. NO. OF PAGES
28
22. PRICE
EPA Form 2220-1 (9-73)
24
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