EPA-AA-SDSB-82-10
Technical Report
Testing of the Mack ETSA-676 at MVEL
by
Alex Azary
April 1982
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.
Standards Development and Support Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Office of Air, Noise and Radiation
U.S. Environmental Protection Agency
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Table of Contents
Section Page
I. Summary 1
II. Introduction 1
III. Test Results and Correlation With Other Labs 2
IV. Analysis of Testing Problems 3
V. Conclusion 4
VI. Recommendations 4
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I. Summary
The Mack ETSA-676 heavy-duty diesel engine has been tested at
EPA as part of the EMA/EPA testing program. The purpose of this
program is to analyze lab-to-lab variability in emissions
measurements and to assess how well the emissions data generated
at EPA correlates with data acquired through testing at other
laboratories. This engine was scheduled to be tested in turn by
Mack Trucks, Inc. (Mack), Caterpillar Tractor Co. (Cat), and EPA,
and then to be returned to Mack for the final tests on this engine
as part of the program.
EPA's correlation with other labs has been generally
acceptable with a tendency to somewhat higher particulate
measurements in comparison with those of other labs. This was
reviewed in detail in other reports[l,2] and will not be dealt
with further here.
EPA's transient test particulate measurements for this engine
were 7.8 percent higher than Mack's and 31.12 percent higher than
Cat's: .77, .71, and .53 g/BHP-hr, respectively. The transient
values for NOx were 25.2 percent higher than Mack's and 19.3
percent higher than Cat's: 8.45, 6.32, and 6.82 g/BHP-hr,
respectively. The HC emissions measurements at EPA were 49.1
percent lower than Mack's and 28.1 percent lower than Cat's: .57,
.85, and .73 g/BHP-hr, respectively.
Steady-state emission values did not follow the same pattern
as the above listed transient test data. EPA's 13-mode
particulate measurements were 53.5 percent higher than Mack's and
20.9 percent lower than Cat's: .86, .40, and .68 g/BHP-hr,
respectively. NOx measurements were 8.5 percent higher than
Mack's and 19.2 percent lower than Cat's: 6.83, 6.25, and 8.14
g/BHP-hr, respectively. HC emissions were 20.8 percent lower than
Mack's and 8.3 percent lower than Cat's: .48, .58, and .52
g/BHP-hr, respectively.
Mode 6 and Mode 11 particulate emission measurements were not
reported by Mack and the only comparison made is between Cat and
EPA. Cat particulate measurements were 22.4 percent lower than
EPA's in Mode 6 and 58.0 percent higher than EPA's in Mode 11.
The engine has been returned to Mack for the final test in
the schedule and in view of the somewhat inconsistent data
generated by this engine at the labs involved, a final evaluation
of correlation should be delayed pending review of the data
forthcoming from Mack's second test series.
II. Introduction
This report is one of a series of reports presenting results,
analysis and conclusions of testing heavy-duty diesel engines at
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the EPA's Motor Vehicle Emission Lab (MVEL). These engines are
tested in both transient and steady-state modes and the resulting
data is compared with that of other test labs to determine the
amount of variability between labs.
This report discusses the results of testing a Mack
heavy-duty diesel engine, model ETSA-676. Reviewed are some
problems encountered during the course of testing the engine and
the procedures followed to isolate and solve the problems
satisfactorily. Finally, recommendations for improved procedures
will be presented.
III. Test Results and Correlation With Other Test Laboratories
A series of transient tests were run on this engine from
November 16, to December 1, 1981, at which time the particulate
measurements inexplicably rose from a range of .553 to .837 grams
per BHP-hr to values of 1.046+ grams per BHP-hr. The testing was
stopped while propane checks were initiated to detect leaks and
the components in the system were checked. A leaking thermocouple
fitting in the mini-tunnel, a cracked sampling line and secondary
dilution air inlet temperature variations all contributed to the
erratic readings and were corrected.
Testing was resumed with more consistent performance and data
were processed and compared with that of other labs. The test
results from the three labs involved in testing the Mack ETSA-676
engine are shown in Table 1. Shown are composite emissions for
transient tests, and 13-mode steady-state emissions. Table 2
shows the detail of the data summarized in Table 1. Table 3 lists
the cycle performance data for the tests, indicating that all
tests listed were valid.
Examining the data in Table 1, the values for NOx differ
substantially among the three testing labs using EPA's values as a
base: Cat:transient -19.3 percent,* 13-mode +19.2 percent;
Mack:transient -25.2 percent, 13-mode -8.5 percent.
In contrast, other's measurements of HC emissions are well
above those of EPA: Cat:transient +28.1 percent, 13-mode +8.3
percent; Mack:transient +49.1 percent, 13-mode +20.8 percent.
The values for particulates show an even greater dispersion:
Cat:transient -31.2 percent, 13-mode -20.9 percent; Mack:transient
-7.8 percent, 13-mode -53.5 percent. As was noted earlier in the
report, the particulate measurements at EPA are higher than those
of other labs.
^-,-r x Mfr - x EPA ,nr.
Difference = — x 100
x EPA
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IV. Analysis of Testing Problems
As a result of experience gained in testing the baseline and
other engines, a set of recommended procedures was set up to be
observed during subsequent testing of heavy-duty engines. These
procedures were followed during the testing of this Mack engine.
There were, however, some problems incurred which at times
required tests to be voided. As mentioned above, a set of
transient tests was invalidated because of a sudden rise in
particulate measurement. A series of propane leak tests were
performed to identify the cause(s). Among items found and
corrected were:
1. Leaking thermocouple fitting on mini-tunnel - sealed.
2. Sample line split at fitting - repaired.
3. Inlet and outlet temperatures running higher than spec.
- increased length of sample lines.
4. Outlet from exhaust DGM was within 6" of inlet to DGM
- relocated exhaust DGM to vent to air handling system.
5. Scrubbed main tunnel.
6. Inspected all lines and fittings.
7. Verified calibration of all components.
V. Conclusion
Although previous engines tested at EPA had exhibited
particulate measurements higher than those measurements at other
labs, the inconsistent values obtained from this engine at EPA and
Caterpillar preclude any valid conclusion being drawn at this
time. The HC and NOx values are also without a predictable
pattern.
VI. Recommendations
Any final evaluation of test data produced from previous
tests of this engine should be withheld until the second set of
tests being conducted by Mack are concluded. The results from
these tests should then be reviewed and evaluated against the
previous test data produced at all labs involved with this
engine. At this time it may be determined if indeed the engine is
erratic in performance or our labs have other problems to be
isolated and solved.
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References
1. "Emissions Testing of a DDA 6V92TA Heavy-Duty Diesel
Engine Under Transient Conditions," Danielson, Eugene,
EPA-AA-SDSB-80-16, September 1980.
2. Emissions Testing of an IHC DTI-466B Heavy-Duty Diesel
Engine Under Transient Conditions," Danielson, Eugene,
EPA-AA-SDSB-80-18, September 1980.
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Table I
Summary of Mack ETSA-676 Emissions Tests
(g/BHP-hr)
Test
Mack
Cat
EPA
[1]
m
NOx
Site Stat Trans. [1] 13-Mode Mode 6 Mode 11
X
s
s/x x 100
% Diff.[2]
X
s
s/x" x 100
% Diff.[2]
x
s
s/x x 100
Composite C/S-H/S
•
% rHfferpnrp -
6.32
.430
6.8%
-25.2
6.82
.163
2.4%
-19.3
8.45
.265
3.1%
data.
x~ Other -
6.25
.040
.6%
5.30
.057
1.1%
5.70
.311
5.5%
-8.5 -25.8 -11.2
8.14
.387
4.7%
+19.2
6.83
.997
14.6%
x~ EPA
•x
7.60
.255
3.4%
+6.4
7.14
.634
8.9%
100
6.89
.471
6.8%
+7.3
6.42
.382
6.0%
Trans. [1]
.85
.118
13.8%
+49.1
.73
.007
1.00%
+28.1
.57
.064
11.2%
HC
13-Mode Mode 6 Mode 11
.58
.005
.8% 9
+20.8 +520
.52
.055
10.6% 1
+8.3 +20
.48
.020
4.2% 7
.062
.006
.7%
1.39
.057
4.1%
.0 -2.1
.012
.016
.3%
.0
.010
.0017
.0%
1.42
.103
7.2%
0.0
1.42
.021
1.5%
Trans. [1]
.71
.033
4.6%
-7.8
.53
.150
28.4%
-31.2
.77
.030
3.9%
Part.
13-Mode Mode 6 Mode 11
.40
.010
2.5%
-53.5
.68 1
.069
10.1% 10
-20.9 -20
.86 1
.094
10.9% 1
-
.35
.141
.5% 2.
.9 +58.
.74
.020
.1%
79
019
4%
0
50
x EPA
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Transient
Emissions
NOx
HC
Part
Cold x
Hot x
Comp x
Hot_ S
s/x x 100
Cold x"
Hot x
Comp x
Hot S
s/x x 100
Cold x"
Hot x
Comp x
Hot S
s/x x 100
Table 2
Test Site
Mack
6.06
6.83
6.32
.390
5.7%
.99
.78
.85
.066
8.5%
.70
.66
.71
.019
2.9%
Cat
7.04
6.68
6.82
.156
2.3%
.80
.74
.73
.015
2.0%
.66
.56
.53
.059
10.5%
EPA
8.80
8.39
8.45
.296
3.5%
.64
.56
.57
.064
11.4%
.83
.76
.77
.027
3.6%
Filter Efficiency
x 98.0 98.0 98.2
s - 0.95 2.19
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Table 3
EPA/MVEL Mack ETSA-676 Cycle Performance Data
Type/
Limit
C/S
H/S
C/S
H/S
C/S
H/S
C/S
H/S
C/S
H/S
Error
100
35.2
34.3
34.7
34.2
34.7
34.8
34.8
34.5
34.6
34.4
Slope
.970-
1.030
.980
.980
.979
.980
.973
.972
.974
.974
.970
.969
Speed
y- Intercept
+50 RPM .97
24.1
26.0
18.7
17.6
13.9
12.7
26.4
26.5
1.04
1.88
Torque
R2
min
.995
.995
.995
.996
.995
.995
.995
.995
.995
.995
Error
13% .
of Max
Torque
6.4
6.4
6.6
6.6
6.5
6.3
6.4
6.2
6.4
6.4
Slope
77/.S3
1.03
Cold/
Hot
.986
.978
.987
.980
.993
.990
.991
.990
.991
.983
y-Intercept
+15# ~.
5.48
8.35
-2.63
-1.01
-2.9
-1.5
-9.81
-1.121
-2.78
-0.78
R2
85/88
min
Cold/
Hot
.942
.943
.936
.936
.942
.945
.942
.946
.942
.944
Error
8%
of Max
HP
6.5
6.4
6.7
6.7
6.5
6.4
6.5
6.4
6.4
6.4
Slope
S7/.89
-1.03
Cold/
Hot
1.02
1.02
1.01
1.00
1.00
1.00
1.01
1.01
.991
.987
HP
y-Intercept
+5.0 BHP .91
-1.09
-.787
-2.26
-2.15
-2.2
-2.1
-1.90
-1.84
-2.19
-2.02
R2
min
.955
.956
.950
.949
.954
.955
.953
.956
.953
.954
Integrated
HP-Hr
-15% to
+5% Ref.
1.01
1.02
.981
.986
.978
.986
.991
.998
.964
.970
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