United States
Environmental Protection
Agency
Atmospheric Sciences Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S3-84-108 Jan. 1985
&EPA Project Summary
Characterization of Emissions
from Advanced Automotive
Power Plant Concepts
Daniel A. Montalvo and Charles T. Hare
Emissions from three diesel cars
using two fuel formulations were
assessed. The three diesel cars included
a prototype naturally aspirated Fiat
131, a prototype turbocharged Fiat
131, and a 1981 Oldsmobile Cutlass
Supreme. Each Fiat was tested with
and without a prototype catalytic trap.
Vehicle operating procedures used for
test purposes included the 1981
Federal Test Procedures, as well as the
Highway Fuel Economy Test, the New
York City Cycle, and an 85-km/h
steady-state cruise. Both regulated and
unregulated gaseous and particulate
emissions were measured. Organic
solubles in particulate were analyzed
for various constituents and character-
istics, including fractionation by
relative polarity, benzo(a)pyrene, and
mutagenic activity by Ames bioassay.
Application of the catalytic trap
oxidizer system to the Fiat prototypes
resulted in significant reductions of
organic and carbon monoxide emissions
under all transient driving conditions
examined. Total particulate emissions
were reduced an average of 55 percent
with the turbocharged engine and 65
percent with the naturally aspirated
engine. The Ames assay mutagenic
response (revertants/yug) of the particu-
late phase organics was elevated by the
catalytic exhaust after-treatment device;
however, the emission rates (revertants/
km) were reduced an average of 66 per-
cent with the turbocharged and 73
percent with the naturally aspirated
engines.
This Project Summary was developed
by EPA's Atmospheric Sciences Re-
search Laboratory, Research Triangle
Park, NC. to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering
information at back).
Introduction
Continuing concern for diminishing
worldwide petroleum supplies has
prompted a renewed interest in more effi-
cient engine designs as alternates to
gasoline engines now in wide use.
Advanced-concept engines initially con-
sidered for emissions and fuel economy
studies in this program weregasturbines
Stirling cycle, turbocharged (TC) and
naturally aspirated (NA) diesels, Rankine
cycle, stratified charge, and advanced
Otto-cycle. Actual engine availability
permitted evaluation of only a prototype
NA diesel, a prototype TC diesel, and a
1981 production NA diesel. Each
prototype diesel was also evaluated with
a prototype catalytic trap oxidizer system
for particulate emissions control A
"National Average" No. 2 fuel served as
the "primary fuel" or base fuel. Although
a "wide boiler" was initially considered as
a "second" fuel.it became apparent that
the test vehicles would need a higher-
cetane distillate to run properly. Conse-
quently, a "second" fuel which is
basically a No. 2 home heating oil was
chosen to provide a "worst case"
comparison.
Because many emissions have potential
impact on the public health, this study
examined a substantial number of
unregulated tailpipe emissions along
with the regulated emissions (HC, CO,
NO, and particulate) The dynamometer
driving schedules used included the 1981
Federal Test Procedure (three-bag FTP),
four-bag FTP (cold 23-min FTP plus hot
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23-min FTP), Highway Fuel Economy Test
(HFET), New York City Cycle (NYCC), 85-
km/h steady-state, and the "cold 505"
(first 505 s of a cold-start FTP, used for
smoke evaluation only).
Procedure
Vehicles
Three diesel-powered passenger cars
were examined in this program. The
automobiles included a prototype NA Fiat,
a prototype TC Fiat, and a regular produc-
tion 1981 Oldsmobile Cutlass coupe. The
Oldsmobile Cutlass coupe was a low-
mileage (less than 3,000 mi) rental
vehicle, equipped with optional
equipment, including automatic
transmission, air conditioning, power
steering, and power brakes. The
prototype diesels were obtained from the
Federal Department of Transportation,
Research and Special Programs Adminis-
tration, Cambridge, Mass.
Pretest vehicle preparations included
draining of its fuel tank andfuel filter, and
refilling them with the base-line fuel used
in the program. The crankcase oil was
also changed to newQuakerStateSAE 30
SE/CC grade oil, and the oil filter was
replaced with a new filter. Before actual
testing began, each car was conditioned
on the dynamometer at alternating
speeds of 48, 64, and 80 km/h for approx-
imately 80 km.
The Fiats were initially studied without
exhaust aftertreatment, and subsequent-
ly with catalytic trap oxidizers. The
injector pump timings were one degree
before top dead center (TDC) on the NA
Fiat, and three degrees after TDC on the
TC Fiat at the manufacturer's specified
pump lift. The timing was not altered with
the addition of the particulate trap so as to
not cloud or bias the emission results
between the two different exhaust
configurations. No significant operating
difficulties were experienced with the
three test vehicles during this project.
Fuels
Two distillate fuels were used in this
program, a national average No. 2D
(coded EM-329-F) and a higher aromatic
No. 2 distillate, which is marketed as
home heater oil. Detailed specifications
are presented in Table 1.
In all emission tests conducted during
this project, the vehicle was fueled
directly out of a 18.9-L (5-gal) can through
auxiliary fuel lines installed in the vehicle.
At each fuel change, the vehicle fuel filter
was removed and purged with test fuel.
Afterwards, the vehicle was conditioned
on the dynamometer for 48 km (30 mi) at
Table 1. Properties of Test Fuels
Fuel Code
Description
Cetane Number
Cetane Index
Gravity, °API
Density, g/mL
Cloud point. °C(°F)
Flash point, °C f°F)
Viscosity, cs
Gum, mg/100 mL
Total solids, mg/L
Metals in fuel, x-ray
Carbon, %
Hydrogen, %
Nitrogen, ppm
Sulfur. %
Aromatics, %
Olefins, %
Saturates, %
D86, IBP
°C, 5% point
(°F> 10% point
20% point
40% point
50% point
60% point
80% point
90% point
95% point
EP
EM-329-F
"Nat'l. Avg."
No. 2
50.1
52. 1
37.5
0.837
-8 (18)
65 (149)
2.36
14.3
7.4
0
85.8
13.0
48
0.24
21.3
1.7
77.0
191 (377)
211 (412)
219 (427)
231 (448)
251 (484)
269 (517)
290 (554)
307 (585)
323 (613)
340 (644)
EM-469-F
Couch No. 2 Fuel
SWFtl Analysis
48.1
35.2
0.849
12.9
0.18
172 (342)
206 (402)
219 (426)
231 (448)
252 (486)
262 (504)
272 (522)
297 (567)
315 (599)
332 (629)
344 (651)
EPA 6/80
48.0
48.1
35.2
0.849
84.60
14.81
<100a
0.30
39.1
0.9
60.0
182 (360)
218 (424)
262 (504)
309 (588)
337 (638)
alternating speeds of 48 km/h (30 mph),
64 km/h (40 mph), and 80 km/h (50
mph). At the start of the conditioning, the
auxiliary fuel return line from the vehicle
was removed from the test fuel can and
directed to fill a separate waste-fuel
2000-mL container. Upon filling the
container, the fuel return line was
reconnected to the test fuel can to
continue the conditioning and
subsequent 23-min FTP prep prior to
testing. In this manner, an effective
conditioning of the exhaust system and
proper flush of the engine fuel filter and
lines were assured each time a fuel was
changed in a vehicle.
Other Equipment
All emissions tests were conducted in
accordance with procedures specified for
Federal emission certification. A 50-hp
Clayton ECE-50 passenger car
dynamometer was used for all tests. The
dynamometer has a direct-drive variable
inertia system for simulation of vehicle
mass from 454 kg (1000 Ib) to 4082 kg
(9000 Ib) in 57-kg (125 Ib) increments.
The constant volume sampler (CVS) used
for these studies included a 460-mm (18-
in) diameter by 5-m (16-ft)-long dilution
tunnel, which operated at a nominal flow
rate of 12.9 mVmin (455 ftVmin). The
dilution tunnel is shown schematically in
Figure 1, along with sampling stations for
the varied exhaust analyses conducted in
this project. In addition to measurement
of the regulated emissions total hydrocar-
bon, carbon monoxide, oxides of nitrogen,
and total particulate, many unregulated
emissions were examined. The specific
compounds and analytical procedures
are described in Table 2. The category
"individual hydrocarbons" included the
lower molecular weight compounds
methane, ethane, ethylene, acetylene,
propane, propylene, and benzene.
Driving Schedules
Emissions were examined using three
transient driving schedules and one
steady-state condition. The transient
schedules included the FTP simulation of
urban driving with an average speed of
31.4 km/h (19.5 mph), the HWFET
simulation of expressway driving with an
average speed of 77.6 km/h (48.2 mph),
and the NYCC simulation of congested
city central core driving with an average
speed of 11.5 km/h (7.1 mph). The
steady-state condition examined was
85.0 km/h (52.8 mph). The transient
driving schedules are graphically illus-
trated in Figure 2.
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Table 2. Sampling and Analysis Methodology for Unregulated Emissions
Exhaust Emissions
Sampled
Constituent(s) Analyzed
Sampling Method
Analysis Method
gases individual hydrocarbons
aldehydes
phenols
hydrogen sulfide
total cyanide
ammonia
organic sulfides
organic amines
N-nitrosamines
gaseous hydrocarbons
sample bag (CVS)
impinger
impinger
impinger
impinger
impinger
trap
impinger
ThermoSorb/N trap
trap
injection, GC/FID
DNPH. GC/FID
extraction, GC/FID
methylene blue derivative.
spectrophotometer
cyanogen chloride derivative. GC/ECD
ion chromatograph
injection, GC/FPD
GC/NPD with ascarite pre-column
GC coupled to TEA analyzer*
extraction, GC/FID
paniculate
size distribution
trace elements
carbon, hydrogen, and nitrogen
sulfate
impactor-filter
filter, 47 mm Fluoropore
filter, 47 mm glass
filter, 47 mm Fluoropore
gravimetric
x-ray fluorescence
combustion/TC analyzer
barium, chloranilate derivative (BCA),
HPLC/UV
paniculate
organic
solubles
smoke
organic solubles
benzofajpyrene (BaPj
boiling point
carbon and hydrogen
nitrogen
biological response
polarity profile
smoke (visible)
500 x 500 mm filter
optical
Soxhlet extraction, gravimetric
HPLC/fluorescence detection
GC/FID
combustion/TC analyzer
oxidation pyrolysis/chemiluminescence
Ames bioassay
HPLC/fluorescence and UV detection
EPA smokemeter (continuous)
*lf interferences occurred with GC/TEA analysis, a further analysis using HPLC/TEA was required.
(Bags)
CO, /V0» COa.
Individual Hydrocarbons (IHC)
Exhaust .4 T
Out U-
/
(47 mm Filters)
Paniculate Gravimetric
Paniculate C. H, and N
Trace Elements
Sulfate
N-nitrosamines (ThermoSorb/N Trap)
Dilution Tunnel
460 mm(18")I.D.
Filtered
Air In
I
Continuous
HC Analyzer
Orifice
Mixing Plate
(Impingers)
Aldehydes & Ketones
Phenols
Hydrogen Sulfide
Total Cyanide
Ammonia
(Traps)
Organic Sulfides
Gaseous HC
Paniculate
Impactor
s. Sizing
Amines (Raw Exhaust)
Exhaust
from
Test Vehicle
filters)
Percent
Organic
Solubles
Ames Bioassay
Benzofajpyrene
Polarity Profile
G.C. Boiling Point
C, H, andN
Figure 1. Emissions sampling system.
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Transient
Phase
Stabilized
Phase
200
400
600 800
Time, s
1000
1200 1371
100
80
jz 60
| 40
20
0
200
400 600
Time, s
765
100
80
« 60
| 40
20
0
50
5 20
0
NYCC
iWV Li /\ /Vl
200 400 600
Time, s
Figure 2. FTP, HFET, and NYCC driving cycles vs time traces.
Results and Discussion
The major purpose of this project was
to evaluate many different emissions
during dynamometer operation of a
prototype NA Fiat 131 diesel with and
without a catalytic particulate trap, a
prototype TC Fiat 131 diesel with and
without a catalytic particulate trap, and a
1981 production Oldsmobile Cutlass
diesel, under varied transient and steady-
state driving conditions. All test vehicles
were operated using a "National
Average" No. 2 fuel (EM-329-F) and a
second No.2 fuel (EM-469-F), which was
basically a home heating oil.
The project plan was organized to
provide a substantial amount of
information on regulated and
unregulated emissions, with minimum
repetitive testing. The total number of
tests completed included 36 sequences
consisting of a four-bag FTP, HFET, NYCC,
and 85-km/h cycle each. In addition,
more than 138 supplementary tests were
completed consisting of 10 four-bag FTP,
30 hot-FTP, 17 HFET, 39 NYCC, 25 85-
km/h, and 17 cold 505 cycles, and
various trap regeneration tests.
An important finding in this project was
the success of the catalytic traps in
significantly reducing the various
regulated and unregulated organic
emissions from the NA and TC Fiats. An
illustration of the trap oxidizer effective-
ness in organic emissions control is
provided in Figure 3, where HFID total
hydrocarbon, soluble particulate phase
organic (SOF), individual hydrocarbon
(IHC), aldehyde and ketone, and phenol
emissions are indicated for the FTP
driving schedule. Similar observations
were made with the other driving
schedules.
The FTP emissions shown in Figure 3
were generally higher with EM-469-F
than with EM-329-F, but not by substan-
tial amounts. The highest emissions of
HC, SOF, IHC, and aldehydes and ketones
were from the Fiats without aftertreat-
ment. The SOF was the largest portion of
the total HC measured with the Fiats
without aftertreatment, ranging from 25
th 46 percent of the total HC. Catalytic
trap use on the two Fiats significantly
reduced emissions of total HC, SOF, IHC,
and aldehydes. Total hydrocarbons alone
were reduced by an average of 83 percent
on the NA Fiat, and by an average of 64
percent on the TC Fiat. Average reduc-
tions of SOF with catalytic traps were 96
and 88 percent for the Fiat NA and TC
diesels, respectively.
In summary, the following observa-
tions were made during this study:
Catalytic trap use on the NA and TC
Fiats provided acceptable engine
operation on all cycles and with each
test fuel. Over its 1686 km (1048 mi)
of use, the catalytic trap on the NA
Fiat required regeneration every 422
km (261 mi) on the average, while
the trap on the TC Fiat required no
regeneration over the entire 1141
km (877 mi) of its use.
Emissions of CO by the Fiat NA and
TC vehicles were reduced by an
average of 91 percent on the Fiat NA
diesel and 80 percent on the Fiat TC
diesel when the catalytic traps were
used.
With the trap the NOx emissions
from the NA Fiat were increased by
an average of 17 percent. Trap
operation on the TC Fiat reduced NOx
emissions slightly with EM-329-F
and increased them slightly with
EMF-469-F. The effect of trap back-
pressure on the NOx emission
changes observed is not known,
since trap backpressure was not
monitored continuously during
emissions testing performed on the
Fiats.
Regulated particulate emissions
from the Fiats were lower for every
cycle and fuel combination with
catalytic trap than without, by an
average of 65 and 55 percent on the
Fiat NA and TC diesels, respectively.
No major differences in particulate
emissions were observed as a
function of the test fuel for either
vehicle or with any driving cycle
examined.
Methylene chloride soluble organics
were significantly lower with the
catalytic traps on the Fiat NA and TC
diesels than without. Over the five
cycles and two fuels, the average
percent by weight of solubles
decreased from 58 percent with no
aftertreatment to 9 percent with trap
for the NA Fiat, and from 34 percent
with no aftertreatment to 10 percent
with trap for the TC Fiat.
Weak to strong positive mutagenic
responses were obtained on all
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organic solubles from particulate
emitted by the five vehicle configura-
tions and two fuels. Highest overall
mutagenic response in revertants/
/ug was obtained with the trap-
equipped Fiats. On the basis of
revertants/km,however, the trap-
equipped Fiats generally indicated
the lowest mutagenic activity.
Revertants/km of the Fi.ats with
traps were reduced by an average of
73 percent on the NA Fiat and by an
average of 66 percent on the TC Fiat
as compared to corresponding cases
without aftertreatment.
Benzo(a)pyrene (BaP) emission rates
ranged from "not detected" to 30.8
fjg/km with most BaP emission rates
less than 7.8 /ug/km. Highest BaP
emissions on each cycle and with
each fuel were associated with the
two Fiats without aftertreatment.
Employing the catalytic trap,
however, generally reduced BaP
emissions by more than 82 percent
on the NA Fiat, and by more than 53
percent on the TC Fiat.
Fractionation of organic solubles by
HPLC indicated that normalized
relative response was generally low-
est in the transitional region and
highest in the polar region. There
were no correlations between the
normalized peak areas and the Ames
abd BaP results.
Aldehyde emissions were low and
considerably scattered. Formalde-
EM-329-F
EM-469-F
hyde was generally the most
abundant of the "total" aldehydes
evaluated, and at times the only
aldehyde detected. Highest
formaldehyde emissions were from
the Fiats without aftertreatment.
Formaldehyde was reduced by more
than 53 percent with the catalytic
trap on the NA Fiat and by more than
43 percent on the TC Fiat. The FTP
formaldehyde emissions from the
trap-equipped Fiats were low (from
"none detected" to 2.4 mg/km), and
comparable to those obtained in a
separate EPA study using low-
mileage 1978 gasoline cars
equipped with an oxidation-catalyst.
Ammonia emission rates ranged
from 0.43 to 1 1 8 mg/km, with most
emissions measuring under 10
mg/km. Both cold- and hot- FTP
ammonia emissions were reduced
with the catalytic trap on the Fiat NA
diesel.
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Fiat NA
Fiat NA/trap Fiat TC
Fiat TC/trap
Cutlass
Figure 3.
FTP organic emissions of Fiat NA, Fiat TC, and 1981 Oldsmobile Cutlass diesel
vehicles with EM-329-F andEM-469-F fuels.
The phenol compound appearing
most consistently and found in
largest quantities throughout the
study was 2,3,5,6-tetramethyl-
phenol. Although "total" phenol
emissions indicated considerable
variation overall, the results did
indicate some reduction of phenols
with the trap-equipped Fiat.
Carbonyl sulfide and methyl sulfide
were present in the exhaust with all
vehicle configurations, fuels, and
test cycles examined. Emission rates
ranged from 1 .5 to 206 mg/km, and
from 0. 1 5 to 43 mg/km, respectively.
The use of catalytic traps on both
Fiats generally reduced their visible
smoke. Overall, the lowest and
highest smoke emitters were the NA
Fiat with catalytic trap and the TC
Fiat without aftertreatment, respec-
tively.
Particle aerodynamic size generally
increased with trap use on the Fiat
diesels. The largest particles were
observed with the trap-equipped Fiat
NA diesel with about 60 percent of
the particle diameters measuring
more than 0.1 yum.
Elemental analysis indicated low
hydrogen content in most of the par-
ticulate matter examined, suggestive
of dry soot-like particulate material
rather than oily material. There
-------
were no significant elemental con- should be undertaken. Emphasis should
tent differences between fuels. be directed to sulfate emissions.
Nitrogen in particulate matter aver-
aged 0.5 percent overall.
Sulfate emissions were increased by
the catalytic trap in the HFET, NYCC,
and 85-km/h sequences with the
Fiat NA diesel, but were decreased in
all cycles with the Fiat TC diesel. The
largest trap-related increase in
sulfate, as percent of particulate,
occurred in the HFET and NYCC tests
with the Fiat NA diesel (sulfate
emissions were not examined during
trap regeneration).
Trace elements most commonly
found in particulate matter from the
test vehicles included sulfur, mag-
nesium, aluminum, zinc, silicon,
calcium, iron, barium, and phospho-
rus. Sulfur and iron generally
accounted for more than 50 percent
of the "total" trace element
emissions in each cycle. Overall the
emitted elements ranged from 1.2 to
11.8 percent of the total particulate
emissions. Trace element emissions
greater than 3 percent of the total
particulate emission rate were
observed only with the trap-
equipped Fiats.
Analysis for carbon, hydrogen, and
nitrogen in the particulate organic
solubles indicated the presence of
hydrocarbon-like materials with
numeric H/C ratios between 1.58
and 1.95. The lowest H/C ratios
were observed with the catalytic-
trap-equipped Fiats, which may
indicate a higher content of
unsaturated hydrocarbons with the
trap than without the trap.
Conclusions and
Recommendations
The potential for substantial reduction
of organic, carbon monoxide, and partic-
ulate emissions from light-duty diesel
motor vehicles by using catalytic trap
oxidizer exhaust aftertreatment devices
was demonstrated. The examined system
required a modified engine operation
schedule to achieve trap regeneration
when necessary to avoid excessive
engine backpressures. Emissions during
trap regeneration were not examined.
When production trap-equipped diesel
motor vehicles become available, further
emissions characterization, to include
emissions during trap regeneration,
U. S. GOVERNMENT PRINTING OFFICE: 1985/559-111/10767
-------
D. A. Montalvo and C. T. Hare are with Southwest Research Institute, San
Antonio, TX 78284.
R, L. Bradow is the EPA Project Officer (see below).
The complete report, entitled "Characterization of Emissions from Advanced
Automotive Power Plant Concepts," (Order No. PB 85-126 126; Cost: $35.50,
subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Atmospheric Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No G-35
Official Business
Penalty for Private Use $300
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