&EPA
United States
Environmental Protection
Agency
Office of Mobile Source Air Pollution Control
Emission Control Technology Division
2565 Plymouth Road
Ann Arbor, Michigan 48105
EPA 460/3-87-002
June 1987
Air
Study of the Effects of Reduced
Diesel Fuel Sulfur Content
on Engine Wear
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EPA 460/3-87-002
Study of the Effects of Reduced Diesel Fuel
Sulfur Content on Engine Wear
by
Edwin A. Frame
Ruben A. Alvarez
Norman R. Sefer
Southwest Research Institute
6220 Culebra Road
San Antonio, Texas 78284
Contract No. 68-03-3353
Work Assignment B-1
EPA Project Officer: Craig A. Harvey
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Mobile Source Air Pollution Control
Emission Control Technology Division
2565 Plymouth Road
Ann Arbor, Michigan 48105
June 1987
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This report is issued by the Environmental Protection Agency to report technical data
of interest to a limited number of readers. Copies are available free of charge to
Federal employees, current contractors and grantees, and nonprofit organizations - in
limited quantitites - from the Library Services Office, Environmental Protection
Agency, 2565 Plymouth Road, Ann Arbor, Michigan 48105.
This report was furnished to the Environmental Protection Agency by Southwest
Research Institute, 6220 Culebra Road, San Antonio, Texas, in fulfillment of Task f in
Work Assignment No. B-l of Contract 68-03-3353. The contents of this report are
reproduced herein as received from Southwest Research Institute. The opinions,
findings, and conclusions expressed are those of the author and not necessarily those of
the Environmental Protection Agency. Mention of company or product name is not to
be considered as an endorsement by the Environmental Protection Agency.
Publication No. EPA-460/3-87-002
11
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FOREWORD
This project was conducted for the U.S. Environmental Protection Agency by the
Division of Fuels and Lubricants Research, Southwest Research Institute. The project
was to complete Task 4 as authorized by Work Assignment B-l under Contract 68-03-
3353. Work was initiated September 2, 1986, and completed in June 1987. It was
identified within Southwest Research Institute as Project 08-1193-001. The EPA
Project Officer was Mr. Craig A. Harvey, and the Branch Technical Representative
was Mr. Timothy Sprik, both of the Emission Control Technology Division, Ann Arbor,
Michigan. The SwRI project team included Mr. Edwin A. Frame, Mr. Ruben A.
Alvarez, and Ms. Margaret B. Millikin. Mr. Norman R. Sefer was project manager and
was involved in the initial technical and fiscal planning.
111
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ABSTRACT
The study evaluated wear in heavy-duty highway-type engines for reduction of
sulfur content of diesel fuel in the range of 0.50 weight percent to 0.05 weight
percent. A literature review found that wear rates generally were reduced by
decreasing fuel sulfur content. The amount of wear reduction was affected as much
by operating temperature and engine load as by sulfur in the fuel. Low operating
temperatures showed more wear at high sulfur levels and, therefore, more benefit for
low sulfur fuels. Increasing engine load caused higher wear rates independent of sulfur
content. Lubricant alkalinity (Total Base Number) is effective in controlling corrosive
wear at high sulfur levels and reduces the potential wear benefit from low sulfur diesel
fuel. Lubricating oil analyses from fleets operating on diesel fuel with less than 0.05
weight percent sulfur were compared with previous data when average sulfur content
was 0.35 weight percent. Overall, a significant reduction in engine wear occurred in
most engine types as measured by iron content of used oil. Most of the reduction can
be attributed to the low sulfur fuel, with minor contributions from changes in the
lubricating oils.
IV
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TABLE OF CONTENTS
Section Page
FOREWORD - - iii
ABSTRACT - iv
LIST OF FIGURES - vi
LIST OF TABLES - xi
SUMMARY - - .— xii
1. INTRODUCTION - 1
1.1 Background 1
1.2 Objective 1
1.3 Approach 1
2. LITERATURE REVIEW — - - - 2
2.1 Introduction 2
2.2 Discussion of Literature 3
2.3 Comments on SAE Paper No. 700892 21
2.4 Engine Manufacturers 21
3. FLEET DATA ON ENGINE OIL ANALYSES 23
3.1 Initial Contacts With Fleets 24
3.2 Southern California Rapid Transit District Fleet 24
3.3 Chandler, Suppose-U-Drive (Rental Trucks), and Laidlaw
School Bus Fleets 39
ft. CONCLUSIONS AND RECOMMENDATIONS - - 64
4.1 Conclusions From Literature Review 64
4.2 Conclusions From Fleet Data 72
4.3 Recommendations 72
5. REFERENCES - 74
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LIST OF FIGURES
Figure Page
1. Effect of Fuel Sulfur Content on Piston Ring Wear QO) 7
2. Effect of Fuel Sulfur Content on Engine Wear (5) 8
3. Effect of Fuel Sulfur Content on Cylinder Bore Wear UO) 9
4. Effect of Fuel Sulfur Content on Cylinder Liner Wear
With Engine Oil 1 08) - 10
5. Effect of Fuel Sulfur Content on Cylinder Liner Wear,
Engine Oil 1 with Anti-Corrosion Additive (18) 11
6. Relation Between Fuel Sulfur Content and Ring Wear, Single-
Cylinder Four-Cycle Diesel Engine 12
7. Wear Rates with Reduced Sulfur Content 13
8. Effect of Jacket Temperature on Piston Ring Wear with
Fuels of Different Sulfur Content 14
9. Effect of Jacket Temperature on Bore Wear with
Fuels of Different Sulfur Content
10. Piston-Ring Wear Related to Coolant Temperature in a
Two-Stroke Diesel Engine (Unknown fuel S level) 15
11. Effect of Fuel Sulfur Content and Jacket Temperature
on Engine Wear (5) 16
12. Top Compression Ring Chrome Face Wear Rates for
Cummins VT-903 17
13. Effect of Load on Top Ring Wear Rate as a Function
of Outlet Coolant Temperature 18
14. Effect of Load (BMEP and Peak Pressure) on Bore
Wear Rate 18
15. Low-Temperature Corrosive Wear is Reduced by Use of
Alkaline Lubricating Oil Additives 19
16. Corrosive Wear is Reduced Through Use of Alkaline Oil 19
17. TBN/TAN Versus Oil Miles 20
18. Comparison of ASTM D 664 and ASTM D 2896 TBN Analyses 20
19. SCRTD Fleet, Sulfur Content of Diesel Fuel, Trailer and
and Tank Samples 28
VI
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LIST OF FIGURES
(Continued)
Figure
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
SCRTD Fleet, Sulfur Content of Diesel Fuel, Annual Average
SCRTD Fleet, Average Oil Miles
SCRTD Fleet, Average Iron Content of Lubricating Oil
SCRTD Fleet, Average Total Base Number of Lubricating Oil
SCRTD Fleet, Average Oil Miles (CUV903 Engine) -
SCRTD Fleet, Average Iron Content of Lubricating Oil
(CUV903 Engine) -
SCRTD Fleet, Average Total Base Number of Lubricating Oil
(CUV903 Engine) —
SCRTD Fleet, Average Oil Miles of Lubricating Oil
(DDV71 Engine) —
SCRTD Fleet, Average Iron Content of Lubricating Oil
(DDV71 Engine) —
SCRTD Fleet, Average Total Base Number of Lubricating Oil
(DDV71 Engine) ~
SCRTD Fleet, Average Oil Miles (DDV92 Engine) « -
SCRTD Fleet, Average Iron Content of Lubricating Oil
(DDV92 Engine) - -
SCRTD Fleet, Average Total Base Number of Lubricating Oil
(DDV92 Engine)
SCRTD Fleet, Average Oil Miles (MAN866 Engine)
SCRTD Fleet, Average Iron Content of Lubricating Oil
(MAN866 Engine) - -
SCRTD Fleet, Average Total Base Number of Lubricating Oil
(MAN866 Engine) — - - - -
Chandler Truck Fleet, Average Oil Miles
Chandler Truck Fleet, Average Iron Content of Lubricating Oil
Chandler Truck Fleet, Average Zinc Content of Lubricating Oil
Page
29
30
30
31
33
33
34
34
35
35
36
36
37
37
38
38
41
42
42
vu
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LIST OF FIGURES
(Continued)
Figure Page
39. Chandler Truck Fleet, Average Oil Miles (Caterpillar Engine) 45
40. Chandler Truck Fleet, Average Iron Content of Lubricating Oil
(Caterpillar Engine) 45
41. Chandler Truck Fleet, Average Zinc Content of Lubricating Oil
(Caterpillar Engine) 46
42. Chandler Truck Fleet, Average Oil Miles (Cummins Engine) 46
43. Chandler Truck Fleet, Average Iron Content of Lubricating Oil
(Cummins Engine) 47
44. Chandler Truck Fleet, Average Zinc Content of Lubricating Oil
(Cummins Engine) 47
45. Chandler Truck Fleet, Average Oil Miles (Detroit Diesel Engine) — 48
46. Chandler Truck Fleet, Average Iron Content of Lubricating Oil
(Detroit Diesel Engine) 48
47. Chandler Truck Fleet, Average Zinc Content of Lubricating Oil
(Detroit Diesel Engine) 49
48. Chandler Truck Fleet, Average Oil Miles (Mack Engine) 49
49. Chandler Truck Fleet, Average Iron Content of Lubricating Oil
(Mack Engine) 50
50. Chandler Truck Fleet, Average Zinc Content of Lubricating Oil
(Mack Engine) 50
51. Rental Truck Fleet, Average Oil Miles 51
52. Rental Truck Fleet, Average Iron Content of Lubricating Oil 52
53. Rental Truck Fleet, Average Zinc Content of Lubricating Oil 52
54. Rental Truck Fleet, Average Oil Miles (Cummins Engine) 53
55. Rental Truck Fleet, Average Iron Content of Lubricating Oil
(Cummins Engine) 55
56. Rental Truck Fleet, Average Zinc Content of Lubricating Oil
(Cummins Engine) 55
57. Rental Truck Fleet, Average Oil Miles (Detroit Diesel Engine) 56
via
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LIST OF FIGURES
(Continued)
Figure Page
58. Rental Truck Fleet, Average Iron Content of Lubricating Oil
(Detroit Diesel Engine) 56
59. Rental Truck Fleet, Average Zinc Content of Lubricating Oil
(Detroit Diesel Engine) 57
60. Rental Truck Fleet, Average Oil
61. Rental Truck Fleet, Average Iron Content of Lubricating Oil
(Deutz Engine) 58
62. Rental Truck Fleet, Average Zinc Content of Lubricating Oil
(Deutz Engine) 58
63. Rental Truck Fleet, Average Oil Miles (CMC Engine) 59
64. Rental Truck Fleet, Average Iron Content of Lubricating Oil
(CMC Engine) 59
65. Rental Truck Fleet, Average Zinc Content of Lubricating Oil
(CMC Engine) - 60
66. Rental Truck Fleet, Average Oil Miles (Inter-Harvester Engine) 60
67. Rental Truck Fleet, Average Iron Content of Lubricating Oil
(Inter-Harvester Engine) 61
68. Rental Truck Fleet, Average Zinc Content of Lubricating Oil
(Inter-Harvester Engine) 61
69. Rental Truck Fleet, Average Oil Miles (Caterpillar Engine) 62
70. Rental Truck Fleet, Average Iron Content of Lubricating Oil
(Caterpillar Engine) 62
71. Rental Truck Fleet, Average Zinc Content of Lubricating Oil
(Caterpillar Engine) 63
72. Laidlaw School Bus Fleet, Average Iron Content of Lubricating Oil ~ 66
73. Laidlaw School Bus Fleet, Average Zinc Content of Lubricating Oil — 66
74. Laidlaw School Bus Fleet, Average Iron Content of Lubricating Oil
(Cummins Engine) 67
75. Laidlaw School Bus Fleet, Average Zinc Content of Lubricating Oil
(Cummins Engine) 67
IX
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LIST OF FIGURES
(Continued)
Figure Page
76. Laidlaw School Bus Fleet, Average Iron Content of Lubricating Oil
(Detroit Diesel Engine) 68
77. Laidlaw School Bus Fleet, Average Zinc Content of Lubricating Oil
(Detroit Diesel Engine) 68
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LIST OF TABLES
Table Page
1. Attitude of Diesel Engine Builders Relative to Sulfur
Content of Diesel Fuel 22
2. Average Iron Concentration, ppm, for Southern California
Rapid Transit District Fleet 27
3. Comparison of Fuel Sulfur Content For Southern California
Rapid Transit District Fleet 28
4. Comparison of Selected Data For Southern California Rapid
Transit District Fleet 29
5. Comparison of Selected Data for Southern California Rapid
Transit District Fleet By Engine Type 32
6. Comparison of Selected Data For Chandler Truck Fleet
7. Comparison of Selected Data For Chandler Truck Fleet By
Engine Type
8. Comparison of Selected Data For Rental Truck Fleet 51
9. Comparison of Selected Data For Rental Truck Fleet
By Engine Type 54
10. Comparison of Selected Data For Laidlaw School Bus
Fleet (Total Fleet) 65
11. Summary of Fuel Sulfur Effects 69
XI
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SUMMARY
The effect of diesel fuel sulfur content on wear in heavy-duty highway diesel
engines was studied in a two-phase approach. In the first phase, a literature review
investigated the role of sulfur content in engine wear as affected by engine operating
conditions and lubricating oil quality. Information was also obtained from diesel
engine manufacturers. In the second phase, data were obtained from four fleets in
Southern California operating on diesel fuel containing less than 0.05 weight percent
sulfur. Sulfur content of diesel fuel was controlled at that level by regulation
effective January 1, 1985, in the South Coast Air Basin which includes Los Angeles,
Orange, Riverside, and San Bernardino Counties. Diesel fuel and used lubricating oil
analyses before and after the change were compared in a statistical evaluation.
Fuel sulfur content effects on corrosive engine wear were reported extensively
in the literature. Data obtained with modern engines and lubricants were the most
applicable, particularly in the 0.50 to 0.05 weight percent sulfur range. The main
findings were:
• Reduction of fuel sulfur content results in less engine wear at some
conditions.
• Wear reduction is greater below the normal operating temperature of about
175°F. Therefore, the benefit for low sulfur fuel depends on the amount of
time the engine would operate below normal temperatures.
• Higher engine load increases the amount of wear, independent of sulfur
content.
• Operating temperature, engine load, and fuel sulfur content appear to be
equal in importance as factors in engine wear.
• Lubricating oil alkalinity (Total Base Number) controls engine wear at high
sulfur levels and reduces the potential wear benefits from low sulfur fuel.
• Lower sulfur fuel may allow longer oil change intervals by less TBN
depletion if other oil contaminants are not controlling oil changes.
• Reduction in engine wear from low sulfur fuel may not extend life if other
failure modes are controlling the need for engine overhaul.
xu
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Data from one fleet showed that average sulfur content of diesel fuel was 0.35
weight percent in 1984 and 0.03 weight percent in 1985-1986. Other fleets analyzed
only lubricating oil. The data showed a significant decrease in iron content in the used
oil for most engine types between the 1984 and 1985-1986 periods. Most of the wear
reduction can be attributed to the lower sulfur diesel fuel. However, there were
changes in the new lubricating oils (TBN alkalinity and zinc anti-wear additive) which
could be minor contributors to the reduction in wear metal. Some engines showed no
reduction or an increase in iron levels after the change in fuel sulfur content.
Xlll
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1. INTRODUCTION
1.1 Background
A study prepared for EPA by Energy and Resource Consultants, Inc. (ERC)
investigated the effect of diesel fuel sulfur content on engine wear.U)* ERC
concluded that a reduction of diesel fuel sulfur content from 0.27 to 0.05 weight
percent would result in a 30 to 40 percent reduction in engine wear and therefore a 30
to 40 percent increase in engine life and oil drain interval. These conclusions were
based primarily on the results of a study by Tennyson and Parker presented in SAE
Paper No. 700892 (2), which was conducted in a two-cycle locomotive engine.
However, today's engine oils have additive packages which are better able to handle
the corrosive wear from fuel sulfur, and some uncertainty exists in extrapolating the
locomotive engine results to on-road diesel operations. A further investigation was
initiated into the effects of low-level diesel fuel sulfur content on engine wear.
L2 Objective
The objective of this work was to determine the overall magnitude of the effect
of diesel fuel sulfur content on the wear of heavy-duty diesel engines in on-road
service, on engine life, and on oil drain intervals. The range of fuel sulfur levels of
interest are from 0.05 weight percent to current U.S. levels (approx. 0.3 weight
percent).
1.3 Approach
The approach included the following work areas:
1. A literature review was conducted to develop an understanding of the role
of diesel fuel sulfur content in the wear of heavy-duty on-road diesel
engines. The effects of engine operating conditions on wear were also
investigated, and the effects of engine oil additives and oil alkalinity
(TBN) were examined.
2. Major U.S. diesel engine manufacturers were contacted for their recom-
mendations regarding operation on low and high sulfur diesel fuels.
3. As an empirical check on the literature study, diesel fleets which are
currently operating on 0.05 weight percent sulfur fuel were contacted to
obtain used oil analyses. This effort was concentrated in the Southern
* Underscored numbers in parentheses refer to the list of references at the end of this
report.
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California area, which has undergone a legislated reduction in diesel fuel
sulfur content to 0.05 weight percent maximum. Comparison was made of
used oil analyses prior to sulfur reduction with those obtained after the
reduction to determine the effect of fuel sulfur reduction on engine wear.
2. LITERATURE REVIEW
2.1 Introduction
In examining the effect of diesel fuel sulfur content on engine wear, it is
advantangeous to use a systems approach. Diesel engine wear is a very complex event
which includes interactions of the following system variables:
• fuel properties (e.g., sulfur content)
• lubricant properties (e.g., alkalinity content)
• engine design and materials
• engine operating conditions
The literature search was designed to obtain information on 1) fuel sulfur
effects, 2) lubricant alkalinity effects, and 3) engine operating conditions on high-
speed diesel engine wear. Engine design and materials considerations were beyond the
scope of this investigation and were not included in the search.
The following five computerized data bases were searched:
1. SAE Global Mobility 1968 - 1986
2. NTIS 1964 - 1986
3. Compendex 1970 - 1986
4. Chemical Abstracts 1967 - 1986
5. DOE Energy 1974 - 1986
In addition, SwRI files on fuel sulfur effects were examined. Overall, a large
body of information on fuel sulfur effects in high-speed diesel engines was found.
Several publications with data in the fuel sulfur range of interest were found which
were not included in the ERC report. In the following sections, a general overview of
fuel sulfur effects on high-speed diesel engine wear and deposits is presented for fuels
in the range of zero to 2 weight percent sulfur. This brief summary documents the
fuel sulfur content/engine wear relationship, and is followed by a detailed discussion of
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data in the zero to 0.3 weight percent fuel sulfur range. Detailed discussions are also
presented for the effects of operating conditions and lubricant alkalinity (TBN) on
diesel engine wear.
2.2. Discussion of Literature
2.2.1 General Diesel Fuel Sulfur Effects
One of the early considerations of fuel sulfur effects was presented in Ricardo's
1933 lecture in which he proposed that much cylinder wear was corrosive and related
to fuel sulfur content.(3) During the 1940's, several researchers reported on the
detrimental effects of sulfur compounds in diesel fuel. Cloud and Blackwood (1943)
used both cyclic and steady-state 80-hour engine test procedures in a Detroit Diesel
3-71, Caterpillar single-cylinder, and Hercules 6-cylinder to determine the effects of
diesel fuel sulfur content on deposits and wear.(4) They reported that an increase in
fuel sulfur from 0.2 to 1.0 weight percent resulted in a two to sixfold increase in
measured piston ring wear, and a two to fourfold increase in cylinder bore wear. A 40
to 80 percent increase in ring zone deposits was observed, as well as increased ring
sticking. Cloud and Blackwood concluded that fuel sulfur type was relatively
unimportant as fuels containing naturally occurring and added sulfur (carbon disulfide
and diamyl trisulfide) produced about the same level of engine distress. Increased
wear and fouling were also caused by the addition of small amounts of SO2 to the
intake air of a fired engine. Addition of SO3 to the intake air of a motored engine
caused dramatic increases in ring wear and deposits. Finally, they reported that 60 to
90 percent of the fuel sulfur was converted to SO3 during the combustion process.
In 1947, Moore and Kent determined the effect of fuel sulfur content on single-
cylinder diesel engine (Caterpillar) wear by using crankcase used oil iron content as an
indication of wear.(5) Fuels containing natural sulfur (0.7 weight percent) and sulfur
added as thiophene (0.7 weight percent sulfur) produced a four to fivefold increase in
iron wear metals compared to the low sulfur baseline. A fuel with 1.3 percent sulfur
present as thiophene gave a sevenfold increase in iron wear metals. They also
reported that reducing engine coolant temperature from 160°F (71°C) to 100°F (37°C)
caused a fourfold increase in wear when using fuels with no sulfur present.
Also in 1947, Blanc of Caterpillar Tractor Co. reported that experiments in a
single-cylinder Caterpillar engine showed that as fuel sulfur content increases, ring
and cylinder bore wear (top) and piston deposits increase.(6) When the sulfur content
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of the fuel is increased above 0.5 percent, the pistons become progressively dirtier,
the ring grooves pack with carbon, and the rings become more sluggish. With sulfur
content greater than 1.0 percent, stuck rings become common. Blanc reported that
distillation range of high sulfur fuels was found to affect deposits somewhat, but not
to the extent that fuel sulfur content impacted on deposits.
In 1948, Gadebusch reported that fuel sulfur content alone is not satisfactory for
predicting engine deposits. He found that a fuel blend of straight run and catalytically
cracked materials which contained 0.6 weight percent sulfur gave more deposits than a
straight run fuel with a sulfur content of 1.15 weight percent.(7) Cattaneo and
Starkman (1948) reported that ring wear increased threefold in going from zero to 1.0
weight percent fuel sulfur and that basic material in the engine oil significantly
reduced the wear.(8) Furstoss (1949) investigated field experience involving small-
bore medium-speed diesels using high-sulfur fuel and reported that operation on fuel
with greater than 0.5 weight percent sulfur resulted in abnormal upper cylinder and
ring wear with increased engine deposits.(9) Also in 1949, Broeze reported that
cylinder bore wear increased twofold and ring wear increased threefold when fuel
sulfur was increased from 0.08 to 1.5 weight percent.0.0) In experiments with a Pyrex
window in the combustion chamber, Broeze observed that increased fuel sulfur content
caused increased lacquer deposits.
After the excellent research of the 1940's, very little information was published
the next 20 years on high-sulfur fuel usage effects in high-speed diesel engines. In
1974 Perry and Anderson of the U.S. Navy reported on the effects of increasing the
sulfur content of diesel fuel marine (DFM).(H.) They found during 1000-hour tests that
in going from 1.0 to 1.3 weight percent fuel sulfur (all naturally occurring), top
compression ring wear increased by a factor of 2.5, and more ring sticking occurred in
both two- and four-cycle diesel engines.
U.S. Army research on high-sulfur fuel utilization was reported by Lestz,
LePera, and Bowen in 1976.(j_2) Using a cyclic operating procedure in an aluminum
block two-cycle diesel engine, they found severe increases in fire ring (1.4 to sixfold)
and bore wear (zero to three fold) when comparing reference fuel (0.4 percent sulfur)
with fuels containing 0.64 and 1.2 weight percent naturally occurring sulfur. Higher
lubricant ash content helped in controlling fire ring and bore wear; however, more ring
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sticking occurred with the higher ash oil. In this work, greater engine distress was
consistently observed with the 0.64 weight percent sulfur fuel than with the 1.2 weight
percent fuel. This greater distress led the authors to speculate that other fuel
components present such as olefinic compounds, oxygenated compounds, naphthenic
acids, and pyrrole nitrogen were contributing to the increased wear.
In 1978, Frame reported that in going from 0.4 to 1.0 weight percent naturally
occurring fuel sulfur, fire ring wear increased fourfold and liner scuffing increased
five to tenfold in a two-cycle diesel engine.U3) No change in engine deposits
accompanied the fuel sulfur increase in this work.
Gergel (1980), reported on modified Cat 1-G2 tests run with fuel containing 1.4
weight percent sulfur, with the additional sulfur added as tertiary butyl disulfide.(_14)
In these tests, which were run without the standard oil drains, piston top groove
deposit filling remained the same while weighted total piston deposit rating (WTD)
increased threefold; and top ring wear, as determined by weight loss, increased
twenty-four fold when the high sulfur fuel was used. Recent work on fuel sulfur
effects has been reported by McGeehan. In 1982 McGeehan found, as Gergel had
earlier, that fuel sulfur content has very little effect on high temperatures (200° to
260°C) piston top groove deposits in a single-cylinder supercharged Caterpillar
engine.(L5) In these experiments, fuel sulfur content was increased by adding tertiary
butyl disulfide to the base fuel. Total piston deposits increased overall with the higher
sulfur fuel due to increased lower area piston deposits at temperatures of 120 to
190°C. In 1983 McGeehan published results of research covering the effects of fuel
sulfur content on diesel engine bore polishing.Q6) He found in going from 0.2 to 1.0
percent fuel sulfur, bore polishing increased two to threefold in the Mack T-6 600-hour
test, and sixfold in the 200-hour Ford Tornado test. Finally, in 1985 Frame reported a
two to threefold increase in used oil iron content when going from zero to 1.0 weight
percent fuel sulfur in a single-cylinder 4-cycle diesel engine operated at 180°F coolant
out temperature.(J7) In this work an unformulated lubricant was used to isolate fuel
effects and to eliminate acid neutralization by the lubricant.
In summary, fuel sulfur content has been shown to be directly related to engine
wear at all fuel sulfur content levels. While many factors such as operating conditions
and lubricant quality impact on engine wear, the effect of fuel sulfur content on
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engine wear is great. In general, for each additional one percent of fuel sulfur
content, (e.g., 0.3 to 1.3 percent sulfur), ring and cylinder bore wear increased
approximately eightfold and fourfold, respectively. Also, increased fuel sulfur content
generally led to additional piston deposits and often even to ring-sticking. Most of the
above references covered fuel sulfur effects which went beyond the range of current
EPA interest. In the following section, research results in the fuel sulfur range of EPA
interest (0.05 - 0.3 weight percent sulfur) are examined in detail. Diesel fuel sulfur
effects in the 0.05 - 0.3 weight percent range are compared with effects in other
sulfur ranges of the same magnitude.
2.2.2 Low-Sulfur Diesel Fuel Effects
The literature review revealed several publications which contained engine wear
data in the zero to 0.3 weight percent sulfur range. Only data which had at least one
actual data point in the zero to 0.3 weight percent sulfur range were considered.
Extrapolations of data from higher sulfur ranges were not considered. Each cited
result will be analyzed in terms of its applicability to current lubricants and on-road,
heavy-duty diesel engines.
Cattaneo and Starkman (1948) reported on the effect of fuel sulfur content on
measured ring weight loss, while operating at a coolant temperature of 210°F.(8) Their
results are plotted in Figure 1, from which it was calculated that in going from 0.3 to
zero weight percent sulfur, ring wear (weight loss) decreased 37 percent. While this
wear decease is large on a percentage basis, the absolute ring wear rate at 0.3 weight
percent sulfur was below 2 mg/HR. The Cattaneo and Starkman data did not specify
the engine type, number of cylinders, speed, or load. In addition, the type and
properties of the lubricant used are unknown; however, at best the oil would be 19*8
vintage, and not of the quality of current engine oils. Because of the above mentioned
unknowns, applicability of these results to current diesel engine wear is questionable.
It is interesting to note that the wear curve appears to be approximately linear over
all sulfur ranges up to 1.4 weight percent sulfur.
Moore and Kent (1947) conducted their work in a single-cylinder Caterpillar
diesel engine operating at 75 BMEP, 160°F coolant out temperature (COT), and used a
formulated, commercial heavy-duty engine oil.(5) As shown in Figure 2, total engine
wear in mg/60 HR as determined by used oil analyses decreased by 43 percent in going
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D)
D)
o -
-i u
0
.5 1
Fuel S, %
Figure 1. Effect of fuel sulfur content on piston ring wear (10)
1.5
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00
L_
o
O)
o
Q)
1200
1000
800
600
Q>
-i 400
"D
C
0 200 h
O)
c.
o -
0
_i L.
.5 1
Fuel S, %
Figure 2. Effect of fuel sulfur content on engine wear (5)
1.5
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from 0.3 to zero weight percent fuel sulfur. In this work, the wear rate increased
above 0.7 weight percent fuel sulfur.
Broeze and Wilson (1949), used a single-cylinder Caterpillar diesel engine
operated at 75 BMEP, with a COT of 140°F.UO) Their results show virtually no
difference in cylinder bore wear for fuels in the zero to 0.5 weight percent sulfur
range as shown in Figure 3. Bore wear started to increase substantially with fuels
which contained greater than 1.0 weight percent sulfur. While the lubricant used in
this work was not described, the fact remains that no decrease in bore wear was
observed from 0.5 to zero weight percent fuel sulfur.
1
Fu«) sul
- i-i
2-0
J
^A
2-5 30
Figure 3. Effect of fuel sulfur on cylinder bore wear (10)
Malyavinskii and Chernov (1958), examined fuel sulfur effects in high-speed
Russian diesel engines, using a formulated engine oil.(18) The engine oil met Soviet
specification COST 5304-50. The TBN of the new oil was not stated and how COST
5304-50 compares to API service classifications is not known. COT was not stated.
As shown in Figure 4, a reduction of fuel sulfur from 0.3 to 0.2 weight percent would
result in approximately a 10 percent decrease in relative cylinder liner wear as
determined by used oil analyses extrapolated to 1000 hours. Figure 5 shows results in
a different engine using the same oil fortified with a supplement anti-corrosion
additive. In this case a reduction of 5 percent in cylinder liner wear would be
expected in going from 0.3 to 0.2 weight percent fuel sulfur.
Pinotti, Hull, and McLaughlin (1949), conducted wear tests in a single-cylinder
diesel engine operating at 175°F COT and 150°F oil sump temperature.(_19) Top
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200
CO
150
0)
100
50
o_o
J.)
o
o
0 -
-I L
0 .5 1
Fuel S, %
Figure *. Effect of fuel sulfur content on cylinder liner wear with engine oil 1 U8)
1.5
-------
LTg
O.E
JO) O)
c
LU
CN
"So
O
200
150
100
50
0 -
0
1.5
Fuel S, %
Figure 5. Effect of fuel sulfur content on cylinder liner wear, engine oil 1
with anti-corrosion additive (18)
-------
compression ring wear was monitored by using an irradiated cast-iron ring. In going
from 0.3 to 0.05 weight percent fuel sulfur, a 15 percent reduction in ring wear was
observed (Figure 6). While the quality of oil used in obtaining Figure 6 data was not
stated, the authors did publish results which reveal the relative ring wear performance
of 19^9 vintage engine oils:
Typical Wear Rates
Iron Wear Rate,
mg per hr.
Uncompounded Oil 1.81
Heavy-Duty Oil Meeting Army
Ordnance 2-104B Spec. 1.06
Heavy-Duty Oil Meeting Caterpillar
Tractor Series 2 Reqmts. 0.65
Fuel sulfur content used in obtaining these wear rates was not specified. The wear
rate for uncompounded oil was similar to that reported by Cattaneo and Starkman
(Figure 1) for 0.3 weight percent fuel sulfur.(8) The ring wear reported by Pinotti, et
al., was linear over the range investigated. (0.05 - 1.2 weight percent sulfur.)
100
Oi
0.4 Oi 0«
PERCENT SULFUR
10
Figure 6. Relation between fuel sulfur content and ring wear, single-cylinder
four-cycle engine, 4Jt-in. bore, 1*00 rpm.l50oF oil sump temperature.
800 F exhaust temperature. 175HF jacket temperature.
Mercedes-Benz Truck Company, Inc. has provided EPA with data on fuel sulfur
effects in a draft SAE paper.(20) A radionuclide technique was used to determine
cylinder liner wear at various fuel sulfur levels and engine operating conditions. Wear
tests were conducted in a four-cycle, direct injection, naturally aspirated V-8 diesel
12
-------
engine with one cylinder bore activated. The engine oil met API service classification
SE/CC and was 20W-20 viscosity grade. The oil had be to be changed frequently to
retain resolution of the measuring method; thus, TBN depletion effect could not be
investigated. Wear tests were conducted at fuel sulfur contents of 1.2, 0.26 and
0.05 weight percent.
An empirical wear equation was developed and validated. The calculated wear
rates for fuels in the range of zero to 0.5 weight percent sulfur are presented in
Figure 7. These diagrams illustrate that a reduction in fuel sulfur level results in a
substantial reduction in engine wear at COT below 80°C (176°F). Reduced corrosive
wear during conditions typical of cold-start and warm-up was observed. For example,
at 50 C (122 F) COT, an 80 percent reduction in cylinder bore wear rate was observed
in going from 0.3 to 0.05 weight percent fuel sulfur. By 70°C (158°F), the reduction
2 10
20
30 AO 50 60 70 80 90 100
COOLANT OUTLET TEMPERATURE l*C1
Figure 7. Wear rates with reduced sulfur content
was 28 percent and at approximately 80°C (176°F) the observed wear rate was the
same for 0.3 and 0.05 weight percent fuel sulfur. Beyond 80°C (176°F), at higher than
normal COT's (>80 to 85°C), fuels with very low sulfur content (0.05 weight percent)
could cause a slight increase in wear rate. Of all the data reviewed, the Mercedes-
13
-------
Benz results appear to be most directly applicable to current U.S. on-road, heavy-duty
diesel engines. Still, current diesel engine oils are of slightly higher quality than API
classification CC, and the Mercedes-Benz experiments did not include highly loaded
turbocharged diesel engines. Both of these factors reduce the applicability of the
Mercedes-Benz data to current U.S. conditions. In the following section, the effects
of engine operating conditions on diesel engine wear will be discussed, and the overall
importance of these effects in relation to fuel sulfur effects will be examined.
4.2.2.3. Operating Condition Effects
The effect of engine operating temperature, generally expressed as coolant out
temperature (COT), on diesel engine wear has been extensively documented in the
literature. Broeze and Wilson (10) documented an increase in piston ring and cylinder
bore wear as COT was lowered, using both high and low sulfur fuels (Figures 8 & 9).
1-5 /sulphur fuel
|X&08Z sulphur fuel
Jesulphurlsed M^sulphurTuel)
Wwr on 1-5/f sulphur fuel of
60'C taken as 100
20 40 60 80
Jacket outlet temp"C
(b(TLe.p.70p.s.l.)
Figure 8. Effect of jacket temperature
on piston ring wear with fuels of dif-
ferent sulfur content.
1000
1 800
>
! 900
?
!|400
!
200
n
ol-b^
x-
ii —
?
^
Jacket outlet temp^C
too
Figure 9. Effect of jacket temperature
on bore wear with fuels of different
sulfur content.
The observed ring wear increase was very slight for 0.08 weight percent fuel sulfur,
and no bore wear increase was observed. Blanc (6) conducted single-cylinder
Caterpillar engine tests using 1 weight percent sulfur fuel and observed the following
increase in top ring wear at lowered COT:
COT, °F 175
Top ring gap increase, IN 0.028
100
0.045
Pinotti, et al. U9) also showed a substantial increase in iron wear rate at reduced COT
(with unknown sulfur content of the fuel):
-------
Jacket
Temperature, F
Load, %
Iron Wear Rate
mg per hr
180
125
100
100
0.48
0.83
Nutt, Landen, and Edgar (1955), reported on the effect of engine jacket
temperature on piston ring wear.(20 Their results, shown in Figure 10, show wear
increasing below 150°F COT.
Z 300
o
X
«
P '00
..5
u«
>
^
2 ioo
75
100 129 ISO
' JACKET TEMPERATURE OE6 f
173
Figure 10. Piston-ring wear related to coolant temperature in a
two-stroke diesel engine (unknown fuel S level)
Moore and Kent (1947), reported that when using 0.7 weight percent sulfur fuel
(HSF), increasing the jacket temperature from 100 to 160°F decreased engine wear by
a factor of nearly 4.5.(5) For a sulfur-free fuel (LSF), the decrease in wear going from
100 to 160°F jacket temperature was slightly less than a factor of 4 (Figure 11). In
comparing the actual wear rates, Moore and Kent found the effect of low coolant
temperature on the rate of wear was nearly as great as increasing fuel sulfur content
by 0.7 weight percent sulfur.
Bolis, Johnson, and Daavetilla (1977) determined the effect of COT on top
compression ring chrome face wear rate.(22) A radioactive tracer method was used to
determine the ring wear rate of the Cummins VT-903 engine. The results are shown in
Figure 12. Somewhat surprisingly, they have shown that ring wear increased with
increasing COT, when using fuel with 0.23 weight percent sulfur. The authors offer
the following explanation for these results:
15
-------
1500
—A—
1200
O>
o
0)
c
o
900
600
300
0 h
0
HSF, 160°F
HSF. 100°F
LSF. 160°F
LSF, 100°F
10
20
30
Hours
40
50
60
Figure 11. Effect of fuel sulfur content and jacket temperature on engine wear (5)
-------
200 •
oc
u
O
i
I
c
IOO
ENGINE SPEED I8OO RPM
LOAD(BMEP) 90% FULL LOAD (117 PSD
INLET OIL TEMP. 205 f
~io5
ieo
200
OUTLET COOLANT TEMPERATURE. »F
Figure 12. Top compression ring chrome face wear rates for
Cummins VT-903, 1800 rpm, 90 percent load 205^F inlet
oil temperature. 0.23 weight percent Fuel S.
"The absence of corrosive wear in our tests indi-
cates that probably some variation in diesel engine design
and/or lubricants has shifted the corrosive wear range
outside our region. Our engine was a turbocharged, non-
aftercooled diesel which would have higher minimum
cycle temperatures and pressures than would a similar
naturally aspirated diesel. Other design factors may also
play an important role in the negligible corrosive wear. It
also widely recognized that lubricants have significantly
improved in their alkalinity capacity during the past 15
years."
We believe the chrome ring was impervious to corrosive wear under the
conditions and durations tested. The Mercedes-Benz data for a nonturbocharged
engine (Figure 7) show that for a given fuel sulfur level, bore wear typically increases
with decreasing COT below normal operating temperature and increases with increas-
ing COT above normal operating temperature.(20) In general, engine wear can be
expected to increase at COT below the normal operating range, with the effect being
magnified by increased fuel sulfur content.
17
-------
The effect of engine load on engine wear has also been documented in the
literature. Increased load caused increased top ring wear at various COT as reported
by Bolis, et al., and shown in Figure 13.(22) The Mercedes-Benz data (Figure 1<0
confirm the higher engine wear at increased load (BMEP and peak pressure).(20) At
83°C COT, the Benz data show load to be of greater importance to bore wear than
fuel sulfur levels of 0.05 and 0.5 weight percent. Thus, increased engine load causes
increased engine wear rate.
200
I
o
100
s
I
2600 RPM
209 f INLET OIL TEMPERATURE
100
120
140
180
2OO
OUTLET COOLANT TEMPERATURE.^
Figure 13. Effect of load on top ring wear rate as a
function of outlet coolant temperature
E
I
-0.3
UJ
IT
cr
0.1
= 0.05V.wt
= 0.50V.wt.
"02468
BMEP fbarl
60 70
PEAK PRESSURE tbar)
Figure 14. Effect of load (BMEP and peak pressure) on bore wear rate
18
-------
2.2.4 Lubricant Alkalinity Effects
Lubricant alkalinity as measured by Total Base Number (TBN) expressed as mg
KOH/g sample has long been recognized as important in controlling the deleterious
corrosive effects of diesel fuel sulfur content. Ellis and Edgar (1953), demonstrated
the reduction of low-temperature corrosive wear by using alkaline lube oil addi-
tives.^) Figure 15 illustrates the effect of lubricant alkaline content on ring wear
for both a two-stroke and four-stroke diesel engine. Figure 16 from the work of Nutt,
.073
.090
.029
9 3/U BORE I30F
tt STROKE
8 3/U BORE
IUOF
2 STROKE
29 50 79 100
OIL ADDITIVE CONTENT HIUIMOLS
Figure 15. Low-temperature corrosive wear
is reduced by use of alkaline lubricating
oil additives. These tests were of 480-hr
duration at water jacket temperatures of
130 and 1*0 F as noted.
10
.
too f
If SULFUR FUEL
2 U
BASE NUMBER MG KOH/G
Figure 16. Corrosive wear is re-
duced through use of alkaline oil
(indicated by base number) in a
four-stroke diesel engine at full
load with a jacket temperature of
100°F.
et al. (1955), also shows the reduction of a low-temperature corrosive wear by using an
alkaline oil. (
Gergel (1980), presented a discussion of diesel engine oil alkalinity values.(24)
The following table lists the approximate TBN level of various diesel engine oils:
Diesel Engine Oil Type TBN
Universal* 6-10
Generation 3 railroad 10
Generation 4 Railroad 13
Medium Speed Marine 20-30
Cross-Head Marine 50-70
* 1.000 percent total sulfated ash oil meeting
API CD, API SF, MIL-L-2104D, MIL-L-46152B.
19
-------
Gergel also presented a discussion of techniques used to measure TBN. It was
concluded that ASTM D 664 measures protective TBN of a used oil, while ASTM
D 2896 gives misleading higher values because it measures both protective TBN and
the less-protective form of TBN which comes from weak nitrogen bases (ashless
dispersants). Figures 17 and 18 illustrate the different used oil TBN values of D 664
Field Test Data - Caterpillar 1693 Engines
(Fuel S nominally 0.3%)
' - -. £u .
w
•a- *
Q '
7
Z t
Z
to «
1
1
1
• ASTM D 2896
Test Conditions
Cat 10
No Oil Drain
500 Hours
1% Sulfur Fuel
ASTM D 664
i u :t 20 :• :i
OIL mic i :an
Jt 31
B xn
Test Hours
Figure 17. TBN/TAN versus oil miles
Figure 18. Comparison of ASTM D 664
and ASTM D 2896 TBN Analyses
and D 2896. In summary, the alkalinity value (TBN) of a lubricating oil has been shown
to be very important in controlling corrosive engine wear at low temperature
operating conditions. Care must be used when discussing new and used oil TBN values
because of the differing values produced by ASTM D 664 and D 2896.
2.2.5 Fuel Lubricity Effect
Diesel fuel sulfur content may affect fuel lubricity according to work of Wei and
Spikes.(25) A high frequency reciprocating machine was used to simulate the lubricity
of diesel fuels in fuel injection pumps. Model sulfur compounds were added to a high-
wear severely hydrotreated fuel as shown in the following table:
Wear Test Results Using Sulfur-Containing Model Compounds
Test Fluid
Fuel 13*
Fuel 13 + cyclopentyl sulphide
Fuel 13 + benzyl mercaptan
Fuel 13 + dibenzyl disulphide
Fuel 13 + dibenzyl disulphide
Fuel 13 + n-dodecylsulphide
S from Added Compound
Wt%
0.01 (100 ppm)
0.01
0.01
1
1
Wear Scar Diameter
(mm)
0.35
0.38
0.40
0.35
0.49
0.39
* Fuel 13 is high wear, severely hydrotreated fuel.
20
-------
The authors concluded that all sulfur compounds tested were pro-wear to some extent
and generally gave increased wear at higher concentrations. This effect should be
further investigated to determine if the reduction of diesel fuel sulfur from 0.3 to
0.05 weight percent would benefit diesel injection pump wear.
2.3 Comments on SAE Paper 700892
The original work plan included a review of SAE Paper 700892 by Tennyson and
Parker (2), to determine the applicability of its results to current on-road, heavy-duty
diesel engine operation during this project. After review comments were received
from other sources, EPA requested no further review of the paper.(26)
2.4 Engine Manufacturers
Six major engine manufacturers were contacted for in-house information which
they could make available concerning fuel sulfur effects in the range of 0.05 to
0.3 weight percent. Only two of the manufacturers were helpful; Caterpillar provided
a brochure (27) on fuel sulfur effects and Mercedes-Benz Truck Co. provided a very
useful draft SAE paper (20) which was referenced in previous sections. Gergel (1980)
published the Table 1 on engine builder recommendations relative to fuel sulfur
content.(24) Based on the information in Table 1, the usual efforts to control fuel
sulfur effects are: 1) more frequent oil changes, 2) specifying new oil minimum TBN,
3) specifying a used oil minimum TBN. In conclusion, all manufacturers tend to regard
TBN depletion as an important parameter.
The following information was obtained from representatives of Detroit Diesel
Allison (DDA) during a telephone conversation, and is presented with their consent.(39)
This information was received too late to be integrated into the literature study, and
written reference for the data has not been released by DDA.
Engine wear studies were conducted at three fuel sulfur levels (0.05, 0.26, 0.95
weight percent). Engine chrome ring wear was determined using a ring irradiation
technique and measuring wear debris in the used oil. Details of the wear tests are
presented in the following summary:
Engine type Four-cycle turbocharged diesel
Operating conditions 1200 RPM max torque
1800 RPM rated horsepower
21
-------
Table 1. Attitude of Diesel Engine Builders Relative to Sulfur
Content of Diesel Fuel
Engine Builder
Caterpillar (28)
Cummins (29)
Daimler-Benz (30)
Detroit Diesel (31,32)
Deutz (33)
International Harvester (34)
MACK
M.A.N. (35)
Mercedes-Benz (36)
Volvo (37)
Position on Diesel Fuel Sulfur Content
U.S.A. A. Drain Interval Reduction
96 Fuel Drain
Sulfur Interval
<0.1.0 25% Normal
B. Standard Drain Interval
1. For fuels up to 1.5% sulfur
2. Oil quality
a. API CD
b. TBN - 20 times % sulfur
c. Unknown fuel sulfur
Area TBN
0757A. ~IO"
Canada 10
All others 20
3. ASTM D 2896 for TBN
I). Oil drain at 50% initial TBN
5. Use wear metal analyses
(chromium & iron) or drain
indication)
U.S.A. 1. Fuel sulfur is recommended not
to exceed 1.0 mass percent
2. Emergency specifications allow
fuel to contain 2.0% mass sulfur.
High TBN oils and shorter drain
intervals to be used. No specific
TBN or drain period specified.
3. Oils of same TBN may not give
same performance.
Germany Reduce drain interval by 50% if
fuel sulfur exceeds 0.5%.
U.S.A. 1. Use fuel below 0.5% sulfur for
most satisfactory performance
2. Reduce drain interval when fuel
is above 0.5% sulfur (No details
given).
3. Applicable for two- and four-
cycle
engines.
Germany Fuel Sulfur Drain Interval, Km
CC/SE CD/SE
<0.5% 10,000 15,000
>0.5% 5,000 10,000
U.S.A. Drain Interval Reduction
Fuel Drain
Sulfur Interval
<0.5% Normal
0.5 - 1.0 50% Normal
>1.0% 25% Normal
U.S.A. No published Position
Germany If high sulfur fuel is used, change
oil when TBN falls to 20% new
oil value.
TBN test method not specified.
Brazil 1. TBN retention as determined by
in-house test is important
2. About 10 TBN minimum
Sweden 1. 0.55 maximum fuel sulfur
2. TBN of used oil must remain
above 50% new oil value by
ASTM D 2896 or not less than
1.0 by ASTM D 664.
22
-------
Coolant out, °F
Oil type API CD, 15W-40, 8 TBN
DDA found a 75 percent decrease in chrome ring wear when going from 0.26 to 0.05
weight percent fuel sulfur content while operating at 184°F COT and 1200 RPM max
torque mode. At 1800 RPM, a lesser wear decrease was observed, however, it fell
within test repeatability range. DDA did not feel that these results could be
extrapolated to engine life at this time.
The DDA results are somewhat in conflict with the Mercedes-Benz data (20), in
that a substantial wear reduction was observed while operating at normal engine
temperature. Differences in the M-B and DDA test parameters included:
DDA M-B
Wear location ring liner
Turbocharged yes no
Oil quality CD CC
Oil viscosity 15W-40 20W-20
Any or all of the above factors could account for the difference in results. This
comparison further exemplifies the complexity of the interrelationships of diesel
engine wear variables. The DDA data are most interesting and EPA should remain
in contact with DDA to obtain any additional data which can be made available.
3. FLEET DATA ON ENGINE OIL ANALYSES
On January 1, 1985, the sulfur content in diesel fuel was reduced by regulation to
0.05 weight percent maximum throughout the South Coast Air Basin, namely Los
Angeles, Orange, Riverside, and San Bernardino Counties in California. This change
provided an opportunity to gather fleet data indicating whether or not lower sulfur
diesel fuel may result in a reduction in engine wear and an increase in engine life and
oil change interval. Data on diesel fuel and used engine oil analyses were sought from
fleets operating in the area before and after sulfur content was changed. This section
describes the data obtained from four fleets, and the statistical analyses of the data.
23
-------
3.1 Initial Contact With Fleets
To investigate the effects of low sulfur content in diesel fuel as it relates to
engine wear, several fleet operators in the South Coast Air Basin area were asked to
participate in the EPA study by providing fuel and used oil analyses. In addition, oil
analysis laboratories were contacted to provide other possible data sources for the
study. The objectives of the study were explained and several requirements were
outlined to establish whether available data could be used in the study.
The following items were deemed necessary for a fleet to be a candidate for the
study:
1. Fleets must have been participating in a scheduled used oil analysis
program during 1984 and 1985, i.e., before and after the effective date of
fuel sulfur regulation on January 1, 1985.
2. Used oil analysis data could be made available on magnetic tape in
compatible format for the computer system at SwRI. Due to time
constraints, it was not feasible to manipulate and compare the data
manually.
Number and Type of Contacts
Eight bus fleets, ten truck fleets, four municipal refuse collection truck fleets,
and seven oil analysis laboratories were contacted. The following fleet operators were
willing to release data, and did so in time for use in the study:
1. Southern California Rapid Transit District
2. Chandler Truck Fleet
3. Suppose-U-Drive Fleet (Rental Truck Fleet)
k. Laidlaw School Bus Fleet
The diesel fuel and lubricating oil analyses for all four fleets were performed in the
laboratories of Analysts, Inc., which provided the data used in the study.
3.2 Southern California Rapid Transit District Fleet
The Southern California Rapid Transit District (SCRTD) is located in Los
Angeles, California, and provides urban transit and suburban service in the county of
-------
Los Angeles. It has approximately 2,500 transit buses powered by Cummins, Detroit
Diesel, and MAN engines. SCRTD has a comprehensive and organized fuel and engine
oil monitoring program in which sampling and analyses are done on a scheduled basis.
Data Obtained
Permission was granted by SCRTD to obtain the diesel fuel and used oil analyses
data from Analysts, Inc., an analytical laboratory with corporate headquarters located
in Rolling Hills Estate, California. The data obtained consisted of a listing of diesel
fuel samples with sulfur content, and magnetic computer tape containing used oil
analysis results for 1984, 1985, and about 10 months of 1986.
Sulfur Content Data
There were a total of 870 diesel fuel samples analyzed for sulfur content in 1984,
1985 and 1986. After a thorough check, thirty samples were deleted due to
duplications and other errors. The data were entered into the SwRI computer system,
and statistical analyses were performed on 191 samples identified as tank farm
(refinery) samples and 649 as tank trailer (delivery truck) samples.
Oil Analysis Data
The magnetic tape with the oil analysis data contained a total of 29,949 records
for 1984, 1985 and 1986. A sample listing of the raw data was produced to identify the
variables in the data base. A listing of the different engine types and frequencies of
observations for each year was produced and analyzed in order to understand the data
and delete entries where a specific engine type could not be identified. Over 80
percent of the deletions were due to errors in engine-type identification. Nine
variables were selected as most likely to be affected by high or low sulfur content in
the fuel. In order to eliminate questionable data, limits were established on six
variables where aberrations had been noted in the raw data. Observations were
deleted where any of the following conditions existed:
1. Zinc (Zn) was less than 500 ppm, indicating erroneous data.
2. Iron (Fe), copper (Cu), and lead (Pb) were 0 ppm simultaneously, which
would indicate missing data.
3. Iron, copper, and lead were 998 ppm, indicating an erroneous reading or an
actual reading exceeding the limits of the spectrometer.
25
-------
Original
Records
29*0
12780
1*229
Deleted
Records
282
31*2
3717
Records
Analyzed
2658
9638
10512
*. Fuel dilution (FOIL) was more than 9 volume percent. Excessive fuel
dilution could affect wear rate or metal analyses.
5. Oil miles were less than 1,000 or more than 30,000, indicating analyses on
unused oil or possible errors in recording data.
The following adjustments were made to the data base:
Year
198*
1985
1986
Frequency distribution plots showing wear elements versus oil miles by engine
type and year group were developed. No general pattern could be observed at 1-9,000,
9-15,000, 15-21,000, or 21-30,000 oil mile intervals. Means and standard deviations
were calculated using the same parameters as with the frequency distribution plots.
No major differences or consistent trends were observed with the variables selected
when compared for the same year at the various oil mile intervals. An example of the
data for various ranges of oil miles is given in Table 2. Iron content in the lubricating
oil shows a consistent increase with oil miles for only the DDV71 engine in 198*.
Other engines show upward and downward trends. Also the trends from 198* to 1985-
86 did not show the same effect at different oil miles. Based on these observations,
the oil miles data were combined into a single average for each year. The selection of
variables to be analyzed was reduced to oil-miles, iron, and total base number (TEN).
Statistical Analysis
The objective of the data analysis was to compare diesel fuel and engine oil
analyses, determining if significant differences occurred between 198* and 1985, and
between 198* and 1986. The method used to compare the means of the variables was
the multiple comparison means test. Specifically, 3.W. Tukey (*0) derived a test
designed for pair-wise comparisons based on the studentized range that can use equal
or unequal sample sizes. This multiple comparison of means test is called the Tukey
test or the "honestly significant difference" (HSD) test. The 95 percent level of
confidence was chosen for this study, which may be stated as the 5 percent level of
significance.
26
-------
Table 2. Average Iron Concentration, ppm, for
Southern California Rapid Transit District Fleet
Oil Miles x
1984
CUV903
DDV71
DDV92
MAN866
1985
CUV903
DDV71
DDV92
MAN866
1986
CUV093
DDV71
DDV92
MAN866
1-9
9-15
15-21
21-30
53.5
86.0
81.7
75.0
50.7
60.8
49.4
104.4
43.7
65.7
52.2
55.5
94.3
84.3
272.0
(1 Sample)
56.7
70.8
54.2
547.3
(3 Samples)
35.0
68.0
49.1
65.1
99.8
76.5
__
72.8
53.4
—
__
65.5
51.6
__
65.3
102.2
__
__
65.8
42.2
__
__
83.4
41.2
__
95.9
Fuel Sulfur Content - Table 3 shows the results of the comparison test of
fuel sulfur content between 1984 and 1985 or 1986. There was a 91 percent
decrease in sulfur content in the tank farm samples while the tank trailer
samples show a decrease of 94 percent between 1984 and 1985-1986. The
combined pool of all samples decreased from 0.35 weight percent sulfur in
1984 to 0.03 weight percent in 1985, and 0.02 weight percent in 1986.
Figures 19 and 20 illustrate the information contained in Table 3.
Fleet Summary of Oil Analysis Variables - Table 4 and Figures 21-23
present the SCRTD fleet summary of oil-miles, iron (Fe) ppm, and total
base number (TBN). There was no significant difference in oil-miles
between the three years. However, there was an average 30 percent
reduction in the iron content between 1984 and 1985 - 1986. There was a
significant difference in used oil TBN of 1.4 between 1984 and 1985, and
1.6 between 1984 and 1986. New oil TBN levels, according to SCRTD
records, were 5.4 for 1984, 7.4 for 1985, and 6.1 for 1986. Although there
was marked increase in the used oil TBN in 1985 and 1986, it corresponds
with the higher TBN's in the new oils used by SCRTD during these years
27
-------
Table 3. Comparison of Fuel Sulfur Content For
Southern California Rapid Transit District Fleet
Sample
Type
Tank Farm
Tank Trailers
Combined
Year
198*
1985
1986
198*
1985
1986
198*
1985
1986
No.
*9
98
**
26
582
41
75
680
85
Sulfur, M%
Mean
0.35
0.03
0.02
0.3*
0.03
0.01
0.35
0.03
0.02
Significant
Difference*
S
S
S
S
S
S
Standard
Deviation
0.09
0.03
0.01
0.13
0.0*
0.05
0.11
0.03
0.03
In comparison of mean values for 1985 and 1986 with 198* at the 95 percent
confidence level;
S means Significant Difference
NS means No Significant Difference
A
LU
O
o
.2
TRAILER SAMPLES
TANK FARM SAMPLES
1984
1985
1986
Figure 19. SCRTD fleet, sulfur content of diesel fuel,
trailer and tank samples
28
-------
LJ
I-
o
o
.5
.4
.3
.2
.1
0
1984
1985
1986
Figure 20. SCRTD fleet, sulfur content of diesel fuel,
annual average
Table 4. Comparison of Selected Data For Southern
California Rapid Transit District Fleet
Variable
Oil Miles
Iron, ppm
Total Base No.
Year
1984
1985
1986
1984
1985
1986
1984
1985
1986
No.
2658
9638
10512
2658
9638
10512
2658
9638
10512
Mean
6531.2
6734.5
6424.8
85.5
57.8
58.8
4.4
5.8
6.0
Significant
Difference*
NS
NS
S
S
S
S
Standard
Deviation
3877.1
4099.6
3859.4
53.6
49.8
44.6
1.0
0.8
0.7
* See Table 3.
29
-------
9000
7000
5000
< 3000
Ld
1000
140
120
0. 100
Q_
j£ 80
Ul
60
40
O
o
O
Of
20
1984
1985
1986
Figure 21. SCRTD fleet, average oil miles
1984 1985 1986
Figure 22. SCRTD fleet, average iron content of lubricating oil
-------
UJ
m 5
ui
V)
< 2
o
1
1984
1985
1986
Figure 23. SCRTD fleet, average total base number of
lubricating oil
(7.4 and 6.1). Therefore, it is not valid to compare used oil TBN's from
year to year because the new oil TEN levels are different. Another
approach was to examine the alkalinity depletion for each year, and
determine if low sulfur fuel resulted in the expected increase in alkalinity
retention. As shown below, no consistent trend is evident in the used oil
alkalinity retention:
Year
1984
1985
1986
New Oil,
Typical
5.4
7.4
6.1
Used Oil,
Average
4.4
5.8
6.0
TBN
Depletion
1.0
1.6
0.1
3. Comparison Analyses by Engine Type - Table 5 and Figures 24-35 show the
comparison results on the four engine types identified in the SCRTD data.
All engines exhibited increased alkalinity levels for 1985 and 1986;
therefore, the observation noted for this variable in Table 4 applies.
31
-------
Table 5. Comparison of Selected Data for Southern California
Rapid Transit District Fleet By Engine Type
Variable
Year
No.
Mean
CUV903 ENGINES
Oil Miles
Iron, ppm
Total Base No.
1984
1985
1986
1984
1985
1986
1984
1985
1986
87
73
15
87
73
15
87
73
15
8841.3
6284.9
6160.0
55.5
51.6
42.5
4.1
5.1
5.4
DDV71 ENGINES
Oil Miles
Iron, ppm
Total Base No.
DDV92 ENGINES
Oil Miles
Iron, ppm
Total Base No.
1984
1985
1986
1984
1985
1986
1984
1985
1986
2054
5111
4836
2054
5111
4836
2054
5111
4836
6545.7
7198.5
6888.2
82.1
63.6
66.2
4.5
5.7
6.0
1984
1985
1986
1984
1985
1986
1984
1985
1986
458
4387
5551
458
4387
5551
458
4387
5551
6165.3
6222.7
6070.0
82.1
50.1
51.6
4.5
6.0
6.0
MAN866 ENGINES
Oil Miles
Iron, ppm
Total Base No.
1984
1985
1986
1984
1985
1986
1984
1985
1986
59
67
110
59
67
110
59
67
110
5459.3
5332.3
3993.6
78.3
130.9
95.9
1.9
4.3
5.2
Significant
Difference*
NS
NS
NS
NS
NS
S
s
NS
Standard
Deviation
4781.0
2509.7
2277.7
40.1
36.7
32.9
0.9
0.9
0.6
3915.7
4316.3
4021.7
65.7
44.7
46.3
1.0
0.9
0.8
3567.6
3803.7
3697.2
65.7
50.7
40.6
1.0
0.6
0.5
1221.0
2641.1
563.2
51.3
153.3
79.3
1.8
1.3
1.4
* See Table 3.
32
-------
V)
Ld
9000
7000
5000
< 3000
Ld
1000
1984
1985
1986
Figure 24. SCRTD fleet, average oil miles (CUV903 engine)
140
Q.
120
LU
100
80
8 60
O 40
0£
20
1984
1985
1986
Figure 25. SCRTD fleet, average iron content of
lubricating oil (CUV903 engine)
33
-------
7
6
QQ 3
0
1984
1985
1986
Figure 26. SCRTD fleet, average total base number of
lubricating oil (CUV903 engine)
9000
7000
LJ
-J
3 5000
o
< 3000
LJ
1000
1984
1985
1986
Figure 27. SCRTD fleet, average oil miles of lubricating
oil (DDV71 engine)
-------
140
120
CL
CL
100
P 80
O
O 60
g-40
20
0
1984
1985
1986
Figure 28. SCRTD fleet, average iron content of lubricating
oil (DDV71 engine)
CD
0
II
1984
1985
1986
Figure 29. SCRTD fleet, average total base number of lubricating
oil (DDV71 engine)
35
-------
CO
9000
7000
5000
< 3000
bJ
1000
1984 1985 1986
Figure 3Q. SCRTD fleet, average oil miles (DDV92 engine)
140
120
E
Q.
0- 100
Ul
80
8 60
O 40
Q£
20
1984
1985
1986
Figure 31. SCRTD fleet, average iron content of lubricating
oil (DDV92 engine)
36
-------
OS
Ul
m
Ul
(SI
m 3
2 2
o
I—
1
wwwk
1984
1985
1986
Figure 32. SCRTD fleet, average total base number of lubricating
oil (DDV92 engine)
Ld
9000
7000
5000
< 3000
LJ
1000
1984 1985 1986
Figure 33. SCRTD fleet, average oil miles (MAN866 engine)
37
-------
140
120
Ld
o
80
60
40
20
1984
1985
1986
Figure 34. SCRTD fleet, average iron content of lubricating
oil (MAN866 engine)
OH
Ld
m
0
1984
1985
1986
Figure 35. SCRTD fleet, average total base number of
lubricating oil (MAN866 engine)
38
-------
a. CUV903 Engines - There was a 30 percent decrease (significant) in the
oil mile averages between 1984 and 1985, 1986. Correspondingly,
although not statistically significant, the iron ppm decreased from 56
ppm in 1984 to 52 ppm in 1985 and 43 ppm in 1986.
b. DDV71 Engines - Here we see a significant increase in oil-miles
between 1984 and 1985, 1986. The iron ppm; however, decreased
significantly by 20 percent; therefore, the decrease in engine wear as
indicated by used oil iron content could be attributed to the low sulfur
content in the fuel.
c. DDV92 Engines - There was no significant difference in the oil-mile
mean for the three year period, however, the iron content exhibits a
sharp decrease from 82 ppm in 1984 to 50 ppm in 1985, 1986. This
translates to a 38 percent difference. The low sulfur content in the
fuel appears to have contributed to this reduction.
d. MAN866 Engines - There was no significant difference in the oil-miles
between 1984 and 1985; however, there was a 27 percent decrease
between 1985 and 1986. It would be expected that the iron ppm would
decrease relative to the oil miles; instead, there is a sharp increase of
45 percent between 1984 and 1985, 1986. It should be noted that
samples for these engines were less than 1 percent of the total data
base. Very few engines contributed data; therefore, if one or two
engines in the group were behaving aberrantly, the analysis as a whole
would be affected. The very large standard deviation for the iron
content as shown in Table 5 supports this observation.
3.3 Chandler, Suppose-U-Drive (Rental Trucks) and Laidlaw School Bus Fleets
1. The Chandler Palos Verdes Sand & Gravel Company is located in Lomita,
California. The fleet consists of 55 gravel trucks powered by Caterpillar,
Cummins, Detroit Diesel and Mack engines, and is on a scheduled used oil
analysis program. The fleet operates exclusively in the basin area.
2. Suppose-U-Drive Truck Rental Company is located in Glendale, Cali-
fornia. There are 152 diesel powered rental trucks of different configura-
tions and sizes. The principal engine types identified are Cummins,
Detroit Diesel, Duetz, CMC, and International Harvester. The fleet, for
39
-------
the most part, operates in the basin area; however, there are a few rental
trucks that are used out of the area.
3. The Laidlaw Transit, Inc. with locations in Los Angeles, Van Nuys, 29
Palms, and Palm Springs, California, operates and maintains a total of 190
school buses powered by Cummins and Detroit Diesel engines. Only the
vehicles operated in the Los Angeles and Van Nuys area were considered
for the study.
Data Obtained
The data on these fleets, provided by Analysts, Inc. laboratory, consisted of a
magnetic tape containing used oil analysis for 198*, 1985, and 1986. Fuel sulfur
content analyses were not available for any of the fleets. Therefore, it was assumed
that these fleets experienced a decrease in fuel sulfur content to 0.05 weight percent
max in 1985.
Oil Analyses Data
The magnetic tape contained a total of 2,152 records. The data were separated
by fleets and listings produced to identify the variables in the data base. It was found
that TBN data were not reported for any of the fleets. Oil mile entries were missing
from the Laidlaw fleet; therefore, the oil mile variable was not used for comparison on
this fleet. The data were prepared for analyses in the same manner as the SCRTD
data. The variable zinc (Zn) was selected for comparison due to a noticeable increase
between 198* and 1985, 1986 in the Chandler and Rental Truck Fleet.
Statistical Analysis
The objectives and methods employed were the same as for the SCRTD fleet.
Data on fuel sulfur content were not available for these fleets; therefore, the
assumption was made that based on geographic location, sulfur content change was
similar to that observed by SCRTD.
1. Chandler Fleet Summary of Oil Analysis Variables - Table 6, Figures 36-
38, present the summary of oil miles, iron (Fe) ppm, and zinc (Zn) ppm.
There was no significant difference in the average oil miles between 198*
and 1985, 1986. Iron content decreased from 50 ppm in 198* to *9 ppm in
*0
-------
Table 6. Comparison oi Selected Data
for Chandler Truck Fleet
Variable
Oil Miles
Iron, ppm
Zinc, ppm
Year
1984
1985
1986
198*
1985
1986
198*
1985
1986
No.
33
275
455
33
275
455
33
275
455
Mean
3993.9
3775.6
3*12.0
50.1
48.6
44.7
1183.0
1818.6
1940.6
Significant
Difference*
NS
NS
NS
NS
S
s
Standard
Deviation
2721.2
2734.5
3112.7
30.8
48.6
43.4
217.7
221.4
161.8
* See Table 3.
6000
5000
UJ 4000
3000
< 2000
UJ
1000
0
1984
1985
1986
Figure 36. Chandler truck fleet, average oil miles
41
-------
80
Q. 60
Q.
Ul
I-
O
o
40
0
1984
1985
1986
Figure 37. Chandler truck fleet, average iron content of
lubricating oil
E
Q.
Q.
Z
UJ
2400
2000
1600
1200
O
o
0 800
z
M
400
0
mm.
1984
1985
1986
Figure 38. Chandler truck fleet, average zinc content of
lubricating oil
-------
1985 and finally to 45 ppm in 1986. However, these differences were not
statistically significant. It is noteworthy to mention that the new oil zinc
content was significantly different (59 percent higher) between 1984 and
1985, 1986. This indicates that different engine oils were used in 1984
and 1985-1986. The increase in zinc content was found to be consistent in
all of the analyses. Therefore, because of the anti-wear properties of
zinc oil additives, any reduction in used oil iron content could be caused in
part by the increase in lubricant zinc level.(41)
2. Comparison Analysis by Engine Type - Table 7, Figures 39 through 50
present the comparison analyses for the different engine types powering
the Chandler truck fleet. The 1984 data were not available for the Mack
engines. Means and standard deviations are included for 1985 and 1986.
a. Caterpillar Engine - There was a significant difference in the mean
oil miles between 1984 and 1985-1986. The iron content for 1985
and 1986 decreased by 11 percent, an expected occurrence but not
relative to the 54 percent decrease in oil-miles. The small sample
size for 1985 possibly played a part in the results.
b. Cummins Engine - There was no significant difference in the
average oil-mile variable for 1984, 1985, and 1986; however, used oil
iron content increased by 97 percent. It appears that the compari-
son was biased by the sample size for 1984.
c. Detroit Diesel Engines - There was no statistical difference in the
oil-miles mean or the used oil iron content between the three years.
There was, however, a significant increase in oil zinc content
between 1984 and 1985-1986. The increase in zinc could result in
less used oil iron content. Overall the expected decrease in used oil
iron content was not observed.
d. Mack Engines - No data were available for 1984 for comparison to
be made; however, there was a proportionate decrease in the oil-
mile mean and the average iron ppm between 1985 and 1986.
3. Rental Truck Fleet Summary of Oil Analysis Variables - Table 8, Figures
51 through 54 present the results of 1984, 1985 and 1986 comparison
analyses of used oil variable means. There were no significant differences
43
-------
Table 7. Comparison of Selected Data for
Chandler Truck Fleet by Engine Type
Significant Standard
Variable Year No. Mean Difference* Deviation
CATERPILLAR ENGINES
Oil Miles
Iron, ppm
Zinc, ppm
CUMMINS ENGINES
Oil Miles
Iron, ppm
Zinc, ppm
198* 6
1985 5*
1986 82
1984 6
1985 54
1986 82
1984 6
1985 54
1986 82
1984 5
1985 74
1986 138
1984 5
1985 74
1986 138
1984 5
1985 74
1986 138
DETROIT DIESEL ENGINES
Oil Miles
Iron, ppm
Zinc, ppm
MACK ENGINES
Oil Miles
Iron, ppm
Zinc, ppm
1984 22
1985 119
1986 185
1984 22
1985 119
1986 185
1984 22
1985 119
1986 185
1984 0
1985 28
1986 50
1984 0
1985 28
1986 50
1984 0
1985 28
1986 50
2966.6 1069.1
1671.9 S 1285.9
1038.6 S 943.4
72.9 24.9
78.2 NS 70.4
50.4 NS 38.5
1160.0 207.6
1794.8 S 237.1
1919.7 S 158.1
5160.0 1424.0
4584.1 NS 2603.0
4404.3 NS 3202.4
9.8 3.4
17.2 NS 7.6
21.6 S 14.5
1240.0 191.1
1808.2 S 176.0
1923.1 S 185.4
4009.0 3162.2
4589.9 NS 2921.8
4251.8 NS 3262.9
53.2 27.6
55.5 NS 44.7
62.3 NS 54.8
1176.3 232.4
1829.9 S 245.9
1957.4 S 147.5
0 0
2235.7 991.8
1458.0 749.9
0 0
45.2 26.8
34.4 19.3
0 0
1844.2 191.3
1960.8 143.2
» See Table 3.
-------
6000
5000
in
LJ 4000
-J 3000
o
< 2000
LJ
2
1000
0
80
E
9-
Q.
Ld
I-
o
o
40
§ 20
1984
1985
1986
Figure 39. Chandler truck fleet, average oil miles
(Caterpillar engine)
1984
1985
1986
Figure 40. Chandler truck fleet, average iron content of
lubricating oil (Caterpillar engine)
-------
2400
- 2000
0.
Q.
« 1600
UJ
I—
o
o
o
M
1200
800
400
1984
1985
1986
Figure 41. Chandler truck fleet, average zinc content of
lubricating oil (Caterpillar engine)
6000
5000
UJ 4000
3000
< 2000
LJ
1000
0
1984
1985
1986
Figure 42. Chandler truck fleet, average oil miles
(Cummins engine)
-------
80
g- 60
UJ
I-
o
o
40
§ 20
0
1984
1985
1986
Figure 43. Chandler truck fleet, average iron content of
lubricating oil (Cummins engine)
2400
P 2000
Q.
Q.
„ 1600
LJ
O
O
1200
800
400
0
1984
1985
1986
Figure
Chandler truck fleet, average zinc content of
lubricating oil (Cummins engine)
-------
6000
5000
4000
3000
< 2000
UJ
1000
0
80
E
Q. 60
0.
LJ
I—
z
o
o
40
g 20
0
1984
1985
1986
Figure 45. Chandler truck fleet, average oil miles
(Detroit Diesel engine)
1984
1985
1986
Figure 46. Chandler truck fleet, average iron content of
lubricating oil (Detroit Diesel engine)
-------
E
Q.
Q.
Ld
O
o
z
N
2400
2000
1600
1200
800
400
0
w,.
W
1984
1985
1986
Figure *7. Chandler truck fleet, average zinc content of
lubricating oil (Detroit Diesel engine)
6000
5000
4000
3000
< 2000
1000
0
1984 1985 1986
Figure 48. Chandler truck fleet, average oil miles (Mack engine)
-------
80
g- 60
40
O
o
§ 20
0
1984
1985
1986
Figure 49. Chandler truck fleet, average iron content of
lubricating oil (Mack engine)
E
Q.
CL
LJ
I—
z
o
o
o
M
2400
2000
1600
1200
800
400
0
1984
1985
1986
Figure 50. Chandler truck fleet, average zinc content of
lubricating oil (Mack engine)
50
-------
Table 8. Comparison of Selected Data
for Rental Truck Fleet
Variable
Oil Miles
Iron, ppm
Zinc, ppm
Year
1984
1985
1986
1984
1985
1986
1984
1985
1986
No.
264
329
384
264
329
384
264
329
384
Mean
7808.0
7514.6
8307.8
74.4
57.3
53.7
1410.9
1674.1
1818.4
Significant
Difference*
NS
NS
S
S
S
S
Standard
Deviation
3019.5
3036.4
3591.5
44.7
31.2
38.1
299.2
263.8
290.6
* See Table 3.
V)
UJ
9000
7000
5000
< 3000
UJ
1000
w.
m
W,
1984
1985
1986
Figure 51. Rental truck fleet, average oil miles
51
-------
E
a
140
120
100
LU 80
I-
O
0
60
O 40
oc
20
0
1984
1985
1986
Figure 52. Rental truck fleet, average iron content of
lubricating oil
2400
c 2000
Q.
Q.
» 1600
1200
O
O
O 800
z
M
400
0
1984
1985
1986
Figure 53. Rental truck fleet, average zinc content of
lubricating oil
52
-------
UJ
<
LJ
1.3E04
1.1 E04
9000
7000
5000
3000
1000
1984
1985
1986
Figure 54. Rental truck fleet, average oil miles (Cummins engine)
between the oil-miles for 198* and 1985-1986. There can be seen,
however, a significant decrease of iron ppm. Normally the iron content
would be expected to remain relatively constant given the closeness in the
oil-mile means. Instead, we see a 25 percent decrease between 198* and
1985-1986. The increase in zinc content from the anti-wear additive may
have had a minor effect on the iron reduction; however, the low sulfur
fuel appears to have significantly contributed to the decrease in iron
content.
Comparison Analyses by Engine Type - Table 9, Figures 55 through 71,
show the comparison analyses for the engine groups in the Rental truck
fleet. The zinc variable shows an increase of approximately 25 percent
thoughout the engine groups. Due to the anti-wear properties of zinc oil
additives, it can be reasoned that zinc may have had an effect in the
reduction of iron ppm in addition to the low sulfur fuel.(*l)
53
-------
Table 9. Comparison of Selected Data for
Rental Truck Fleet by Engine Type
No.
Mean
CUMMINS ENGINES
Oil Miles
Iron, ppm
Zinc, ppm
DETROIT DIESEL
Oil Miles
Iron, ppm
Zinc, ppm
DUETZ ENGINES
Oil Miles
Iron, ppm
Zinc, ppm
CMC ENGINES
Oil Miles
Iron, ppm
Zinc, ppm
INTERNATIONAL
Oil Miles
Iron, ppm
Zinc, ppm
1984
1985
1986
1984
1985
1986
1984
1985
1986
ENGINES
1984
1985
1986
1984
1985
1986
1984
1985
1986
1984
1985
1986
1984
1985
1986
1984
1985
1986
1984
1985
1986
1984
1985
1986
1984
1985
1986
HARVESTER
1984
1985
1986
1984
1985
1986
1984
1985
1986
38
34
51
38
34
51
38
34
51
126
162
200
126
162
200
126
162
200
8
16
20
8
16
20
8
16
20
2
2
4
2
2
4
2
2
4
ENGINES
90
114
108
90
114
108
90
114
108
11110.3
11769.4
13235.8
34.8
32.5
37.3
1347.3
1567.6
1806.4
7973.0
7602.3
8408.5
85.3
62.9
56.4
1363.9
1653.6
1756.4
7633.7
8462.0
7494.0
128.3
82.3
102.1
1932.5
1948.1
2217.7
7038.5
6994.5
5777.5
31.0
18.0
8.7
1115.0
1615.0
1635.0
6211.7
5982.4
5978.7
72.0
53.8
49.3
1463.8
1700.1
1862.2
Significant
Difference*
NS
S
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
S
NS
NS
Standard
Deviation
3194.4
3199.2
4314.5
18.3
18.0
21.1
257.9
204.8
152.7
2753.9
2565.7
2711.5
47.7
33.2
24.2
274.5
302.6
299.7
1507.2
4196.0
3634.0
35.0
30.9
120.3
603.4
245.6
473.1
126.5
747.4
865.7
2.8
8.4
2.7
77.8
134.3
49.3
2140.8
2018.5
2003.4
36.4
26.1
25.8
261.4
186.9
185.7
* See Table
-------
E
a.
a.
140
120
100
80
8 60
40
20
0
1984
1985
1986
Figure 55. Rental truck fleet, average iron content of
lubricating oil (Cummins engine)
E
Q.
Q.
Ul
O
O
2400
2000
1600
1200
O 800
z
N
400
0
1984
1985
1986
Figure 56. Rental truck fleet, average zinc content of
lubricating oil (Cummins engine)
55
-------
9000
7000
5000
< 3000
Ld
1000
1984
1985
1986
Figure 57. Rental truck fleet, average oil miles
(Detroit Diesel engine)
140
Q.
o
120
100
80
60
O 40
Of
20
w.
1984
1985
1986
Figure 58. Rental truck fleet, average iron content of
lubricating oil (Detroit Diesel engine)
-------
E
Q.
Q.
LJ
l-
Z
o
o
2400
2000
1600
1200
O 800
M
400
0
LJ
9000
7000
5000
< 3000
LJ
1000
1984
1985
1986
Figure 59. Rental truck fleet, average zinc content of
lubricating oil (Detroit Diesel engine)
w.
1984
1985
1986
Figure 60. Rental truck fleet, average oil miles
(Deutz engine)
57
-------
140
120
- 100
•>
S 80
Q.
o
60
O 40
20
1984
1985
1986
Figure 61. Rental truck fleet, average iron content of
lubricating oil (Deutz engine)
2400
2000
Q.
Q.
!_• 1600
Ul
1200
O
o
O 800
M
400
1984
1985
1986
Figure 62. Rental truck fleet, average zinc content of
lubricating oil (Deutz engine)
-------
9000
7000
5000
< 3000
ui
1000
m
1984
1985
1986
Figure 63. Rental truck fleet, average oil miles (CMC engine)
140
E
Q.
Q.
120
100
UI 80
h-
o
o
60
O 40
20
0
1984
1985
1986
Figure 64. Rental truck fleet, average iron content of
lubricating oil (CMC engine)
59
-------
E
Q.
0.
o
o
N
2400
2000
1600
1200
800
400
1984
1985
1986
Figure 65. Rental truck fleet, average zinc content of
lubricating oil (CMC engine)
9000
7000
5000
< 3000
UJ
1000
1984
1985
1986
Figure 66. Rental truck fleet, average oil miles
(Inter-Harvester engine)
60
-------
140
E
Q.
120
°-100
•t
I-
Uj 80
O
60
O 40
20
bJ
h-
Z
O
O
1984
1985
1986
Figure 67. Rental truck fleet, average iron content of
lubricating oil (Inter-Harvester engine)
2400
E 2000
0.
CL
1600
1200
_* 800
N
400
0
m,
1984
1985
1986
Figure 68. Rental truck fleet, average zinc content of
lubricating oil (Inter-Harvester engine)
61
-------
9000
7000
5000
< 3000
UJ
1000
E
a.
140
120
100
UJ 80
I-
O
60
O 40
CK
20
0
1984
1985
1986
Figure 69. Rental truck fleet, average oil miles
(Caterpillar engine)
1984
1985
1986
Figure 70. Rental truck fleet, average iron content of
lubricating oil (Caterpillar engine)
62
-------
2400
g 2000
Q.
Q.
^ 1600
UJ
1200
O
o
O 800
z
M
400
1984
1985
1986
Figure 71. Rental truck fleet, average zinc content of
lubricating oil (Caterpillar engine)
Cummins Engines - There was a slight (nonsignificant) increase in
oil-miles between 1984 and 1985. There was, however, a significant
increase in oil-miles in 1986. The used oil iron content was
statistically the same for all three years. The iron content
increased from 33 ppm in 1985 to 37 ppm in 1986. This coincides
with the 12 percent increase in oil-miles for the same period. The
level of zinc increased by 25 percent between 1984 and 1985-1986,
which could be impacting the wear. For 1986, the increased oil
miles would be expected to increase used oil iron content, while low
sulfur fuel and higher oil zinc content would be expected to
decrease iron. Overall, no clear effect could be determined.
Detroit Diesel Engines - There was no significant difference in oil-
mile means between 1984, 1985, and 1986. Iron content was reduced
from 85 ppm in 1984 to 63 in 1985 to 56 in 1986. The increase in oil
zinc concentration may account in part for the 30 percent reduction
63
-------
in iron wear. Low sulfur fuel appears to have had a considerable
effect in reducing iron wear.
c. Deutz Engines - There were no statistically significant differences
in the three variables (oil-miles, iron, zinc) of concern.
d. CMC Engines - The oil-mile means were not significantly different.
The iron content shows a 56 percent reduction, while the zinc level
increased by *5 percent. The very small number of samples
probably invalidates the comparison results.
e. International Harvester Engines - Although not statistically signifi-
cantly, there was a * percent decrease in oil-mile means between
198* and 1985-1986. For the same period, iron content shows a 28
percent decrease from 72 ppm in 198* to 5* in 1985 to *9 in 1986.
The sample sizes were approximately even for the three years
compared. Although part of the reduction in iron concentration can
be attributed to the 22 percent increase in zinc content, low sulfur
fuel appears to be related to the decrease.
5. Laidlaw School Bus Fleet Summary of Oil Analyses - Table 10, and Figures
72 through 77 present the fleet summary and engine group analyses. The
Laidlaw fleet did not report oil-mile readings with the data; therefore,
averages were not calculated. Due to the relationship between oil-miles
and iron wear, it was not possible to make an assessment of the results.
The data are included as a matter of information.
*. CONCLUSIONS AND RECOMMENDATIONS
*.l Conclusions From Literature Review
Throughout the literature, fuel sulfur content has been related to corrosive
diesel engine wear. A summary of the effects of decreasing the fuel sulfur content
from 0.3 to 0.05 weight percent is presented in Table 11. The data from Mercedes-
Benz (20) are the most relevant to current lubricants and engines. Extrapolation of
earlier results (8, K), _18, 19) would seem to be tenuous because they were obtained
with older oil formulations quite different from the improved lubricants which are
available today. The results presented in Table 11 are conflicting. Broeze and Wilson
(10) found no reduction in wear below 0.5 weight percent sulfur, even though they were
operating at a relatively cool jacket temperature of 1*0°F and using a lower quality
19*9 vintage lubricant. M-B found great reductions in wear for low sulfur fuels
-------
Table 10. Comparison of Selected Data For
Laidlaw School Bus Fleet (Total Fleet)
Variable
Oil Miles
Iron
Zinc
CUMMINS ENGINES
Year
1984
1985
1986
1984
1985
1986
1984
1985
1986
No.
58
92
123
58
92
123
58
92
123
Mean
DATA
31.8
27.3
49.5
1367.2
1349.1
1350.3
Significant
Difference*
NOT
NS
S
NS
NS
Standard
Deviation
AVAILABLE
20.2
17.3
57.9
109.7
113.2
78.8
Oil Miles
Iron
Zinc
1984
1985
1986
1984
1985
1986
1984
1985
1986
25
45
60
25
45
60
25
45
60
DATA
32.9
25.4
41.4
1382.0
1332.0
1345.8
DETROIT DIESEL ENGINES
Oil Miles
Iron
Zinc
1984
1985
1986
1984
1985
1986
1984
1985
1986
33
47
63
33
47
63
33
47
63
DATA
31.0
29.1
57.4
1356.0
1364.8
1354.6
NOT
NS
S
NS
NS
AVAILABLE
20.6
19.1
30.4
120.1
109.2
80.3
NOT
NS
S
NS
NS
AVAILABLE
20.2
15.3
74.7
101.7
115.8
77.7
* See Table 3.
65
-------
60
50
a
a
UJ
I-
O
o
30
20
O
Of
Q.
Q.
O
O
10
1984
1985
1986
Figure 72. Laidlaw school bus fleet, average iron content of
lubricating oil
2400
2000
1600
1200
O 800
400
0
1984
1985
1986
Figure 73. Laidlaw school bus fleet, average zinc content of
lubricating oil
66
-------
60
50
Q.
Q.
l-T 40
LJ
o
o
Q.
Q.
O
o
30
20
10
1984
1985
1986
Figure 74. Laidlaw school bus fleet, average iron content of
lubricating oil (Cummins engine)
2400
2000
1600
1200
O 800
z
M
400
1984
1985
1986
Figure 75. Laidlaw school bus fleet, average zinc content of
lubricating oil (Cummins engine)
67
-------
60
£ 50
Q.
Q.
. - 40
O
o
30
20
10
0
1984
1985
1986
Figure 76. Laidlaw school bus fleet, average iron content of
lubricating oil (Detroit Diesel engine)
2400
£j 2000
Q.
Q.
^ 1600
Ul
1200
O
O
O 800
M
400
1984
1985
1986
Figure 77. Laidlaw school bus fleet, average zinc content of
lubricating oil (Detroit Diesel engine)
68
-------
Table 11. Summary of Fuel Sulfur Effects
Reference
Number
Fuel S Reduction
(Moore &
Kent)
5
(Cattano &
Starkman)
8
(Broeze & Wilson) (Malyavinski &.
Chernov)
10 IS
(Pinotti, Hull,
McLaughlin)
19
(Rosow M-B)
20
(0.3 to 0.05 weight percent) Effects
COT, °F
Wear
Bore wear Reduction
Ring Wear Reduction
Total Engine Wear Reduction
Comments on Applicability to
Engines and Lubricants
Limitations
160
X
X
43%
Current
1947, HD
Commercial
oil
210
X
37%
(1.2 mg/HR
@ 0.05% S)
X
Unknown Lube
1948 vintage
140 NS*
None 10%
(0.3 to 0.2%S)
X X
X X
Unknown Lube Formulated Oil
1949 1958 Russian
Engines
175
X
15%
X
1949 Oil
Formulation
122/158/176
80%/28%/0
X
X
SE/CC Oil
Non-turbo-
charged
Engines
* Not Stated.
-------
operating below 175°F COT. The Mercedes-Benz data and others reveal the extreme
importance of operating temperature (COT), when examining fuel sulfur effects. The
amount of benefit from wear reduction when operating on fuels with 0.05 weight
percent sulfur would appear to be directly related to the accumulated amount of time
the engine operated at COT below 175°F. This time would vary depending on the type
of duty cycle involved. For example, on-road line haul diesel engines experience less
accumulated cold start and warmup time than engines used for in-city delivery service
with frequent stops. Mercedes-Benz data also indicate a possible wear increase for
low sulfur fuels at higher than normal COT. Overall, a single figure cannot be
extrapolated from the literature for reduction of engine wear when operating on 0.05
weight percent sulfur diesel fuel, due to the strong temperature dependence of the
engine wear/fuel sulfur relationships. Other factors and effects such as TBN and
engine load also have important impact on the wear/fuel sulfur relationships.
Other effects investigated were oil alkalinity (TBN) level and engine load. Oil
TBN level is very important in controlling corrosive engine wear. Operation on 0.05
weight percent sulfur fuel could allow longer oil drain intervals because of reduced
TBN depletion. No data were found which could be used to extrapolate and quantify
the expected increase oil of alkalinity retention when using 0.05 weight percent sulfur
fuel.
As engine load increases, engine wear can be expected to increase as shown in
Figure 1M20) At the normal operating temperature point (175° - 180°F) where there
was no effect of fuel sulfur content on wear, (according to Mercedes-Benz) the effect
of engine load on wear was fairly substantial.
Overall, operating temperature, load, and fuel sulfur content appear to be of
equal importance when discussing diesel engine wear. The complexity and interrela-
tionship of fuel sulfur content, operating temperature, engine load and lubricant
alkalinity on diesel engine wear prevent making simple generalizations regarding the
effects of any one of these variables. Care must also be used in extrapolating changes
in used oil iron content, measured ring wear, and/or cylinder wear to expected engine
life. As stated in API comments to EPA (38), the primary reasons for engine overhaul
when using today's commercial diesel fuel (0.3 weight percent sulfur average) are:
70
-------
• Loss of oil control because of
- bore polishing resulting from excessive top land piston deposits which
remove lubrication from the cylinder walls
- piston ring scuffing resulting from over-fueling, overheating or lack of
oil
- broken piston rings resulting from deformation of aluminum piston
grooves or overuse of Jacobs brakes
• Mechanical failures
- bearing failures due to fatigue or oil contamination
- camshaft failures due to manufacturing quality control problems
- injector failures causing over-fueling, piston burning, and/or ring scuff-
ing
These reasons for engine rebuild do not appear to be directly related to corrosive
ring and liner wear.
The following is quoted from the API comments:
"Information available in the literature (SAE Papers Nos.
831721 and 821216), indicates that it is not piston ring or liner
wear that determines when engines are overhauled, but a
variety of other problems. The most important of these
problems is loss of oil control, as indicated by the MVMA
survey. This loss of oil control is generally caused by bore
polishing, ring scuffing, or broken rings. Bore polishing occurs
when excessive deposits of hard carbonaceous material in the
top ring land abrasively remove the the Crosshatch pattern on
the liner. Piston ring scuffing results from over-fueling,
overheating, or lack of oil. Broken piston rings are caused by
the deformation of the aluminum piston grooves or overuse of
Jacobs brakes."(38)
Thus, the expected reduction in engine wear from reducing fuel sulfur content to less
than 0.05 weight percent may not extend engine life (time to overhaul), due to the
relative importance of other engine failure modes.
71
-------
4.2 Conclusions From Fleet Data
From the results of the statistical analyses, it was concluded that there was a
significant decrease in used oil iron content for several engine types between 1984 and
1985-1986. Anomalies existed in several comparisons of engine types. However, small
sample sizes probably had an effect on the results. Based on the fleet summaries and
individual engine comparisons, specifically the DDV71 and DDV92 (SCRTD) and
Cummins, Detroit Diesel and International Harvester (Rental Truck Fleet), a
consistent reduction in used oil iron content occurred as a result of lower sulfur
content in the diesel fuel and other changes such as oil zinc content and new oil TBN.
We cannot extrapolate the reduction in used oil iron content to increased engine life.
In addition to the fuel sulfur reduction between 1984 and 1985, other variables which
can affect engine wear were changing. Oils with different total base number were
used for each year at SCRTD. The lowest average TBN in 1984 did not go below the
minimum levels recommended by engine builders for mandated oil changes (Table 1,
page 22) where wear rate would be affected by low TBN. Also, the oil zinc content
was significantly higher in 1985 and 1986 for oils used by the Rental Truck Fleet. It
appears that the zinc increase (approximately 28 percent) was not a major contributor
to the decrease in wear metal content, because the lower zinc content oil used in 1984
was still in a typical range for diesel engine oils and should have provided adequate
wear protection.
It is, therefore, concluded that the reduction in diesel fuel sulfur content had an
effect in reducing engine wear for some, but not all of the engine types and fleets
examined.
4.3 Recom mendations
Since neither the literature survey nor the fleet data completely defined the
effect of low sulfur fuel on diesel engine life, additional research is needed. The
following recommendations are offered for consideration.
EPA should continue to monitor fleet operation on low sulfur diesel fuel. By
tracking new engines which enter a fleet operating on low sulfur fuel, and eventually
disassembling and measuring the wear of representative engines, a determination of
low fuel sulfur content on engine life can be made. Oil drain interval extension could
be determined at the same time.
72
-------
Another possibility is to conduct well-defined engine dynamometer durability
tests using low sulfur fuel. While very costly, engine dynamometer tests allow control
of variables such as engine load, COT, and oil TEN so that the fuel sulfur effects can
be isolated and quantitatively determined. Engine manufacturers have procedures for
extrapolating engine life from durability tests. Conduct of durability tests using low
sulfur fuel could provide the needed engine life extrapolation. Engine manufacturers
should be encouraged to use fuel with a maximum of 0.05 weight percent sulfur for
endurance testing.
The possible fuel lubricity effect of fuel sulfur components should be
investigated using bench wear tests such as the BOCLE or Cameron-Plint rig. Results
should determine if the low sulfur fuel will show a benefit or detriment in this area.
73
-------
5. REFERENCES
1. C.S. Weaver, C. Miller, W. Johnson, and T. Higgins, "Diesel Fuel Quality Effects
on Emissions, Durability, and Performance: Preliminary Feasibility and Cost-
Effectiveness Analysis for a Nationwide Fuel Quality Regulation," report under
EPA Contract #68-01-6543, Energy and Resource Consultants, 1985. Informa-
tion also presented in SAE Paper 860622 "Reducing the Sulfur and Aromatic
Content of Diesel Fuel: Costs, Benefits, and Effectiveness for Emissions
Control," February 1986.
2. T.A. Tennyson and C.K. Parker, "Locomotive Radioactive Ring Studies of Fuel,
Lubricant, and Operating Variables," SAE Paper No. 700892, November 1970.
3. H.R. Ricardo, "Some Notes and Observations on Petrol and Diesel Engines,"
Diesel Engine User's Association Meeting, 1933.
4. G.H. CLoud, and A.J. Blackwood, "The Influence of Diesel Fuel Properties on
Engine Deposits and Wear," SAE National F&L Meeting, Cleveland, OH, June 2-
3, 1943.
5. C.C. Moore, and W.L. Kent, "The Effect of the Nitrogen and Sulfur Content of
Fuels on the Rate of Wear in Diesel Engines," SAE Annual Meeting, Detroit, MI,
January 6-10, 1947, and SAE Transactions, October 1947.
6. L.A. Blanc, "Effect of Diesel Fuel Characteristics on Engine Deposits and Wear,"
SAE National F&L Meeting, Tulsa, OK, November 6-7, 1947, and SAE Quarterly
Transactions, Vol. 2, No. 2, April 1948.
7. H.M. Gadebusch, "The Influence of Fuel Composition on Deposit Formation in
High Speed Diesel Engines," SAE National Tractor and Diesel Engine Meeting,
Milwaukee, WI, September 1948.
8. A.G. Cattaneo and E.S. Starkman, "Fuel and Lubrication Factors in Piston Ring
and Cylinder Wear," American Society for Metals Summer Conference on
Mechanical Wear at MIT, June 1948.
9. R.J. Furstoss, "Field Experience with High Sulfur Diesel Fuels," SAE Quarterly
Transactions. Vol. 3, No. 4, October 1949.
10. J.J. Broeze and A. Wilson, "Sulfur in Diesel Fuels-Factors Affecting the Rate of
Engine Wear and Fouling," Institution of Mechanical Engineers, Automobile
Division, March 1949.
11. C.F. Perry and W. Anderson, "Recent Experiences with Sulfur in Distillation
Type Fuels Burned in U.S. Navy Diesel Engines," Paper No. 74-DGP-4, U.S. Navy,
ASME Diesel and Gas Engine Power Conference and Exhibit, Houston, TX, April
28 - May 2, 1974.
12. S.J. Lestz, M.E. LePera, and T.C. Bowen, "Fuel and Lubricant Effects on Army
Two-cycle Diesel Engine Performance," SAE Paper No. 760717, presented at
Automobile Engineering Meeting, Dearborn, MI, October 1976; also available as
Interim Report AFLRL No. 80 AD A031885, September 1976.
74
-------
13. E.A. Frame, "High Sulfur Fuel Effects in a Two-Cycle High Speed Army Diesel
Engine," Interim Report AFLRL No. 105, AD A069534, May 1978.
14. W.C. Gergel, "Trends in Diesel Engine Lubrication Requirements," presented at
45th Midyear Refining Meeting of American Petroleum Institute, 1980.
15. 3.A. McGeehan, B.3. Fontana, and 3.D. Kramer, "The Effects of Piston Tempera-
ture and Fuel Sulfur on Diesel Engine Piston Deposits," SAE Paper No. 821216,
1982.
16. 3. A. McGeehan, "Effect of Piston Deposits, Fuel Sulfur, and Lubricant Viscosity
on Diesel Engine Oil Consumption and Cylinder Bore Polishing," SAE Paper No.
831721, 1983.
17. E.A. Frame, "Fuel Component and Heteroatom Effects on Deposits and Wear,"
Interim Report BFLRF No. 190, AD A166839, December 1985.
18. L.V. Malyavinskii and I.A. Chernov, "The Effect of Sulfur Content in Fuel on the
Performance of Engines," USSR All-Union Scientific Research Institute of
Petroleum Industry, Proceedings of the 2nd Scientific Session Chemistry of
Organic Sulfur Compounds in Petroleum and Petroleum Products, 1958 published
by NSF, 1963.
19. P.L. Pinotti, D.E. Hull, and E.3. McLaughlin, "Application of Radioactive Tracers
to Improvement of Fuels, Lubricants, and Engines," SAE Quarterly Transactions,
Vol. 3, No. 4, October 1949.
20. Letter Mr. G.W. Rossow, Mercedes-Benz Truck Company, Inc., to Mr. Charles
Gray, U.S. Environmental Protection Agency, December 18, 1986, transmitting
draft SAE paper on "Diesel Fuel Sulfur and Cylinder Liner Wear of a Heavy-Duty
Diesel Engine," E.K. 3. Weiss, B.B. Busenthuer, and H.O. Hardenberg.
21. H.V. Nutt, E.W. Landen, and 3.A. Edgar, "Effect of Surface Temperature on
Wear of Diesel-Engine Cylinders and Piston Rings," SAE Transactions, Vol. 63,
1955.
22. D.A. Bolis, 3.H. 3ohnson, and D.A. Daavetilla, "The Effect of Oil and Coolant
Temperatures on Diesel Engine Wear," SAE Paper 770086, 1977.
23. 3.C. Ellis and 3.A. Edgar, "Wear Prevention by Alkaline Lubricating Oils," SAE
Transactions, Vol. 61, 1953.
24. W.C. Gergel, "Interrelation of Diesel Engine Lubricant Quality and Sulfur
Content of Diesel Fuel," National Petroleum Refiners Association Fuels and
Lubricants Meeting, FL-80-83, November, 1980.
25. D. Wei and H.A. Spikes, "The Lubricity of Diesel Fuels," Wear, Vol. Ill, No. 2,
September 1, 1986.
75
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26. Letter, T.L. Sprik, EPA to N.R Sefer, Southwest Research Institute,
2 October 1986.
27. "Fight Fuel Sulfur - Your Diesel's Silent Enemy," Caterpillar Tractor Co.,
Publication SEBD0598, October 1982.
28. H.E. Davis, "High Sulfur Fuel-New Diesel Engine Lubrication Recommendations,"
Caterpillar Tractor Company information letter, June 18, 1980.
29. Cummins Engine Company, "Fuel for Cummins Engines," Bulletin Number
33769001-03, March 1980.
30. Daimler-Benz Specifications for Operative Materials, Group 200, Sheet 215.3.
31. Detroit Diesel Allison, "Fuel and Lubricating Oils for Detroit Diesel Engines,"
Bulletin 7SE 270 (Rev. 12-79).
32. Detroit Diesel Allison, "Fuel and Lubricating Oils for Detroit Diesel Fuel Pincher
Engines," Bulletin 7SE 369.
33. Klockner-Humboldt-Deutz AG, Technisches Rundschreiben, TR0199-1063E,
Cologne, 1.9.78.
34. International Harvester Company, "High Sulfur Fuel Advisory," Bulletin No.
ESB-79-34, September 1979.
35. M.A.N., Service Bulletin on Unfavorable Operating Conditions.
36. Industriale Aditivos do Brazil, S.A.
37. Translation of Volvo memo to Lubrizol Scandanavia, "Specifications of Longlife
Oils," May 7, 1980.
38. "Comments from API in response to EPA's Federal Register Requests for
Comments on Diesel Fuel Quality," (Re 51 FR 23*37, June 27, 1986).
39. Telephone conversation February 11, 1986, between E.A. Frame of SwRI and J.
Fisher, M. Balnaves, and A. Tuteja of Detroit Diesel Allison.
40. R.G. Miller, Simultaneous Statistical Inference, Mc-Graw-Hill Publishing Co.
New York, NY, 1966.
41. J.A. McGeehan, et al., "Some Effects of Zinc Dithiophosphate and Detergents on
Controlling Engine Wear," SAE Paper No. 852133, 1985.
76
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TECHNICAL REPORT DATA
(Please read instructions on the reverse before completing)
1. REPORT NO.
460-3-87-002
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
STUDY OF THE EFFECTS -OF REDUCED DIESEL FUEL
SULFUR CONTENT ON ENGINE WEAR
5. REPORT DATE
June 1987
6. PERFORMING ORGANIZATION CODE
7. AUTHOJMS,)
Edwin A. Frame
Ruben A. Alvarez
Norman R. Sefer
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
Work Assignment B-l
9. PERFORMING ORG-\NIZATION NAME AND ADDRESS
Southwest Research Institute
6220 Culebra Road
San Antonio, Texas 78284
11. CONTRACT/GRANT NO.
68-03-3353
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
2565 Plymouth Road
San Antonio, Texas 78284
13. TYPE OF REPORT AND PERIOD COVERED
Final (9-86/6-87)
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The study evaluated wear in heavy-duty highway-type engines for reduction of
sulfur content of diesel fuel in the range of 0.50 weight percent to 0.05 weight
percent. A literature review found that wear rates generally were reduced by
decreasing fuel sulfur content. The amount of wear reduction was affected as
much by operating temperature and engine load as by sulfur in the fuel. Low
operating temperatures showed more wear at high sulfur levels and, therefore,
more benefit for low sulfur fuels. Increasing engine load caused higher wear
rates independent of sulfur content. Lubricant alkalinity (Total Base Number)
is effective in controlling corrosive wear at high sulfur levels and reduces
the potential wear benefit from low sulfur diesel fuel. Lubricating oil analyses
from fleets operating on diesel fuel with less than 0.05 weight percent sulfur
were compared with previous data when average sulfur content was 0.35 weight
percent. Overall, a significant reduction in engine wear occurred in most engine
types as measured by iron content of used oil. Most of the reduction can be
attributed to the low sulfur fuel, with minor contributions from changes in the
lubricating oils.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Diesel Fuel
Sulfur Content
Engine Wear
Wear Metals
Lubricating Oil Analyses
Heavy-Duty Engines
13. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
89
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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