Front Cover
 Table of Contents
 Back Cover

Title: Diesel fuels and oils
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00084568/00001
 Material Information
Title: Diesel fuels and oils
Physical Description: Book
Creator: Harrison, D. S.
Publisher: Florida Agricultural Extension Service, Institute of Food and Agricultural Sciences, University of Florida,
Copyright Date: 1966
 Record Information
Bibliographic ID: UF00084568
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: 213812843 - OCLC

Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
    Back Cover
        Page 12
Full Text



Diesel Tractors Gaining Popularity .............. ........................... 3
Diesel Compression Ratios .... ..... ..... ................ .. ...... 3
Properties of Diesel Fuels ... ... ........... .................... ..... ........ 3
Selection of Diesel Fuels ........................
Special Handling Instructions for Diesel Fuels 5
Keeping Fuel Clean in the Engine ........... .6................... 6
Oil Classification for Diesel Engines 6............ ....... 6
The API System and How It is Used ....... ............ 7
Additives in Lubricating Oils ............. ...... ..... .... ... 7
Table 1-Limiting Requirements for Diesel Fuels ........... 9
Table 2-API Crankcase Oil Service Classification .....10
Table 3-An Example of Viscosity Recommendation for
Crankcase Oil ........ ............. .. .. 10

100 100

90 -._ GASOLINE- 90
80 GASOLINE _. _L.P. GAS _80
S70- __70

60 \60
0o 50 50

6 40 A40
0 30 __30
W 20 /_20

S10. ___ 1- I-10
_.- ... -" i .. -I"

1952 1954 1956 1960 1964 1965


D. S. Harrison and J. F. Beeman'

Diesel Tractors Gaining
Diesel tractors are gaining popu-
larity in the farm equipment field
at a rapid pace. According to fig-
ures released by the Farm Equip-
ment Institute and Implement &
Tractor in 1965, 51 percent of the
total U. S. production of farm trac-
tors (wheel type) were diesel, 45
percent were gasoline and 4 per-
cent were LP-gas. This compares
with 1955, when only 12 percent
were diesel, 87 percent were gaso-
line and fewer than one percent
were LP-gas.
The trend over the past six years
has been a rapid increase in pro-
duction and use of diesel tractors
and a rapid decline in gasoline trac-
tors, with LP-gas tractors holding
at 4 to 5 percent of total U. S. pro-
duction for domestic use (Figure
Diesel Compression Ratios
Compression ratios for diesel
engines are considerably higher
than for spark ignition engines and
may range from 14 to 1 to as high
as 22 to 1. The reason for the high
compression ratios in diesel en-
gines is that the air in the cylinder
must be compressed enough to
bring its temperature to between
900 and 1450 degrees F. At these

temperatures, fuel injected into
the compressed air will ignite spon-
taneously and provide a rapid re-
lease of energy to run the engine.
Properties of Diesel Fuels
The performance and life of a
diesel engine are greatly affected
by the nature and quality of the
fuel used. The following guides are
intended to help the operator get
better service from diesel tractors.
As in the case of spark-ignition
engines, most diesel engines burn
liquid petroleum fuels. For con-
venience, petroleum fuels will be
called diesel fuels-the customary
popular designation. The impor-
tant characteristics of diesel fuels
from the standpoint of service are
ignition and combustion quality,
density, heat of combustion, vola-
tility and impurity content.
Ignition Quality
Ignition quality (characteristics)
of a diesel fuel is particularly im-
portant. Combustion in gasoline
and diesel engines follows similar
steps, the principal difference is
the much higher compression ra-
tios and firing pressures in the
diesel engine. These high pressures
have a decided effect on the fuel
ignition quality, which, in turn, is
related to knocking.
Knocking occurs in both gasoline

1 Associate Agricultural Engineer, Agricultural Extension Service and As-
sistant Agricultural Engineer, Agricultural Experiment Station, Agricul-
tural Engineering Department, Institute of Food and Agricultural Sciences,
University of Florida, Gainesville.

and diesel engines. It occurs in a
gasoline engine because the fuel
burns too rapidly and in the diesel
engine because the fuel ignites too
slowly. Diesel fuels with poor ig-
nition quality do not begin to burn
as they are injected. These un-
burned fuels accumulate in the
combustion chamber and burn ex-
plosively causing excessively high
pressures and knocking.
Knocking occurs in the diesel en-
gine because of too high pressure
during the burning period of the
combustion cycle. The knock ten-
dency is considered to be propor-
tional to the rate of pressure rise.
An audible knock also depends on
engine design.
The ignition quality of diesel
fuels is designated by the cetane
number. This is analogous in many
respects to the octane number for
gasoline and other spark-ignition
fuels. Most manufacturers recom-
mend the fuel best suited for their
engine. In most cases these recom-
mendations will include the cetane
rating of the fuel. Usually, a
range of values will be given. These
cetane ratings can easily be match-
ed by the local fuel supplier.
A cetane rating between 40 and
60 is usually considered satisfac-
tory for diesel engines used for
farm operations; however, many
manufacturers require a minimum
rating of 45. It is important to be
sure that the cetane rating meets
the minimum recommended by the
engine manufacturer.
Finally, low cetane fuels often
cause difficult starting and slow en-
gine warm up. This may in turn
cause the formation of harmful de-
posits in the engine.
Combustion Quality
A diesel fuel should not only ig-

nite properly, it should burn com-
pletely without leaving deposits
or residues in the combustion
chamber. The success of the diesel
engine depends on prompt and
complete combustion of the fuel.
When there is excessive late burn-
ing due to the inclusion of material
in the fuel which is difficult to burn,
there will be a loss of power and
unburned residues will begin to
build up on cylinder walls and
around injection nozzles.
When a black smoke exhaust is
observed, it may be caused by fuel
with poor combustion quality.
Density and Heat of Combustion
These two factors represent the
amount of energy available in a
fuel. Density, of course, refers to
the weight per unit volume of the
fuel. Diesel fuels should not be
lighter than necessary to assure
clean burning, since light fuels are
lower in BTU content.
The heat of combustion refers to
the amount of energy released
when a given amount of the fuel is
burned. Of course, it is desirable
to obtain a fuel with a high heat
of combustion.
(a) Water, Sediment-The pres-
ence of water in diesel fuels is det-
rimental; it causes rough running
and reduced power. It may inter-
fere with proper metering of fuel
through the injection system. It
may result in burned injectors and
in some cases burned pistons. Since
water is only slightly heavier than
diesel fuel it settles out very slow-
ly in the tank.
A completely distillate fuel is
clean when it leaves the plant.
However, special emphasis should
be placed on keeping it clean right

up to the time it enters the engine
combustion chamber.
Much of the solid material which
may get into the fuel is abrasive.
When it reaches the fuel injection
equipment it wears the finely fitted
parts and the precision of the
equipment is destroyed. This
causes a loss in power, incomplete
combustion, costly operation, hard
starting and unwarranted main-
tenance costs. Other solids may
build up on moving parts and have
similar effects.
(b) Ash and Sulfur Diesel
fuels suitable for agricultural trac-
tors should have a negligible ash
content. A maximum of 0.02 per-
cent ash is often specified. How-
ever, any measurable ash content
is undesirable.
Sulfur will burn the same as the
other combustible components of
the fuel. It will deliver a consider-
able amount of heat. However, its
combustion often causes corrosion.
When engines are run steadily or
lubricated with special oils made
for high sulfur fuels, 1 percent sul-
fur content is often allowed. Nor-
mally, it is desirable to maintain a
low sulfur content.

Selection of Diesel Fuels
Standards have been established
that include different levels of the
elemental properties described
above. Manufacturers of diesel en-
gines will list in the "operator's in-
structions" the grade diesel fuel
necessary to proper function in a
given engine. Maximum perform-
ance will be obtained by following
the manufacturer's recommenda-
tions on diesel fuel.
To avoid trouble due to lack of
power, always use the fuel that
meets the proper specifications as

described in your operator's man-
ual; and be sure your dealer gives
you the grade fuel required. Im-
portant factors in selection of fuel
are grade, cetane rating, and sulfur
and water content.
The two standard grades of die-
sel fuel for tractors, as established
by the American Society for Test-
ing Materials (ASTM) are Number
1 diesel fuel (No. 1-D), and Num-
ber 2 diesel fuel (No. 2-D). The
properties of these two fuels are
shown in Table I. Both are used in
high speed diesel engines; how-
ever, No. I diesel fuel is recom-
mended for colder weather because
it provides for easier starting and
contains less impurities.
While No. 2 diesel is a heavier
fuel, it supplies more gross heat
per gallon (making it desirable for
heavy work loads). It also has a
higher viscosity which provides
better lubrication to the injectors
and often costs less. No. 2 diesel
is more commonly recommended
for farm tractors used in Florida.
Your tractor operator's manual
will give the proper grade to use
and also specify a minimum cetane
rating. This rating is a measure
of the self ignition and burning
qualities of diesel fuel, of which
anti-knock is only one quality.

Special Handling Instructions
for Diesel Fuels
Fuel filters on diesel tractor en-
gines should not be relied on to
remove all harmful foreign sub-
stances. In some cases the mesh in
these filters is larger than the tol-
erances on the injection system.
Even small amounts of dirt will
restrict the flow through the filters
in a relatively short time and re-
quire frequent cleaning. When the

fuel is kept clean there will be no
more than traces of solid material
on the fuel filters at the regular
periodic service changes.
Delivery of diesel tractor fuel in
drums or small volume containers
should be avoided. The longer the
containers are used, the greater
the probability of contamination.
When it is necessary to purchase
fuel in drums or barrels, containers
should be allowed to stand undis-
turbed for a period of time to allow
the contaminants to settle out.
Barrel pumps should be used for
drawing off the fuel and a small
amount should be left in the bot-
tom of the barrel. Fuel for trac-
tors should never be removed from
barrels by tipping the barrel and
pouring the fuel. This method al-
lows dirt and other foreign ma-
terial from the edge of the barrel
to contaminate fuel.
Diesel fuel transported in tank
trucks should be transferred to the
farm storage tank by a pump and
hose. Eliminate exposure of the
fuel to air and small containers
wherever possible. The use of
buckets and funnels should be
avoided in fueling tractors for the
same reasons. Tractors should be
fueled from a storage tank with a
lift pump.
Since diesel fuel is lighter than
water, water in the fuel will collect
in the bottom of the storage tank.
Therefore, the suction pipe on the
pump should not extend to the bot-
tom of the tank. After a period of
use, the tank should be completely
drained, or a pipe reaching to the
bottom of the tank should be placed
on the pump and the water pumped
out, or the water should be drained
from an opening at the bottom of
the tank. When possible the fuel

supply tank should be equipped
with a filter and sediment or drain
bowl. After a storage tank has been
refilled by a supplier, the operator
should wait 24 hours for water and
dirt particles to settle out of the
fuel before it is used.
The nozzle on the discharge hose
of the storage tank should be cov-
ered with a cap until ready for use,
and should be wiped clean before
fueling a tractor.
Keeping Fuel Clean
in the Engine
Keeping the fuel clean in the
engine is just as important as
a clean fuel source. The primary
and secondary fuel filters should be
serviced and cleaned as specified in
the operator's manual. Fuel filters
should also be replaced periodically
or as specified in the manual. When
the filter has been clogged it will
show up in the engine by a loss of
power. The engine will misfire or
skip at full load. Always follow the
operator's manual in replacing and
servicing the filter element.
When a diesel engine runs out of
fuel, it is necessary to vent or bleed
the fuel system of air. Air in the
system makes it impossible for the
pump to inject fuel into the cylin-
ders. The lines must be full of
fuel in order for the engine to
start. The proper procedure for
venting is always found in the
operator's manual.
Remember, Keep Diesel Fuel
Oil Classification for
Diesel Engines
Lubricating oil with a service
designation "DG" is usually speci-
fied for diesel tractors in an opera-
tion where there are no severe

requirements for wear, or deposit
control due to fuel, or engine de-
sign characteristics.
As a general rule most diesel
farm tractors in Florida operate
under more severe conditions than
described in "DG" service. "DG"
service lubricating oils can be used
for engines running at continuous
rated loads at moderate tempera-
tures and using fuel of low sulfur
content. No. 1 diesel fuel has a
sulfur content of less than half of
one percent and can thus be con-
sidered as a low sulfur-content
Lubricating oils with a service
"DM" are usually specified for most
diesel tractors that use fuel con-
taining less than 0.5 percent sulfur.
A "DM" oil also contains greater
quantities of additives than "DG"
type oil. Oil designated "DM" is
suitable for most tractors burning
No. 1-D diesel fuel.
Lubricating oils with a service
"DS" are for diesel tractors operat-
ing under very severe conditions,
or having design characteristics
which tend to produce excessive
wear or deposits. The most severe
service is covered by this classifi-
cation, such as hot weather, inter-
mittent operation and changing
For diesel engines running under
"DS" service conditions, but where
engine design makes it undesirable
to use oils in the "DS" classifica-
tion, the operator's manual or lu-
brication chart will indicate which
lubricating oil should be used. In
addition, where a "DS" service oil
is not available a high detergency
("HD") oil of any reputable brand
may be used as a temporary ex-
pedient until the desired type is

Properties of different service
designations and viscosities for
lubricating oils are listed in Tables
II and III.

The API System and
How It Is Used
Most manufacturers label oil
containers with a viscosity and
service classification. Just as there
are multi-viscosity oils, there are
also multi-service oils. For ex-
amnle, an oil could be marked "For
service MM, MS and DG." In such
a case the oil meets all require-
ments for each of the three classi-
fications. Service designations
"MM" and "MS" are for spark-ig-
nition engines.
Some operators feel it desirable
to change an engine oil to a more
severe classification. This must be
done with extreme caution. For
example, changing from a "DG" to
a "DS" oil may not be recommend-
ed because "DS" oils contain great-
er quantities of detergents. The
detergent, which is added to the
oil to keep carbon and other parti-
cles in suspension, will loosen and
clean carbon deposits in the engine
and will probably cause high oil
consumption. Also, the loosened
deposits can clog oil passages and
filters and reduce lubrication of
some parts of the engine. This
danger can be eliminated or re-
duced by changing oil and filters
frequently until the engine is
Additives in Lubricating Oils
Lubricating oil additives are sub-
stnces which reduce or counteract
undesirable fu el contaminants.
When an additive functions by a
physical means, it simply mixes
with the lubricant or fuel. When

the additive acts in a chemical way
it reacts with the lubricant chemic-
ally and forms a new product.
Commonly used additives include
detergents, anti-oxidants, rust and
corrosion inhibitors, and anti-foam
Many additives are carefully
blended in the oils during the
manufacturing process. The type
and amount of material added de-
pends on severity of the service of
an oil. For example, an oil for "DS"
service has many more additives
than an oil intended for "DG"
service. A "DS" oil is intended for
the most severe running conditions
of an engine, while "DG" oil is in-
tended for comparatively light or
normal service. The extra addi-
tives in the "DS" oil are reflected
in its higher cost.
Listed below is a description of
the function of some of the addi-
tives used in lubricating oils.
Detergents form a coating
around dirt and other particles
nonsoluble in oil and keep them in
suspension in the oil. This is the
reason why detergent oil discolors
much quicker than non-detergent
oil. This discoloring also is a reason

why it is impossible to determine
condition of an oil by color. As long
as particles stay in suspension they
do not deposit on bearings and
other surfaces. This results in a
cleaner running engine.
Rust and Corrosion Inhibitors
Main reason for adding these
compounds is to prevent corrosion
of metal surfaces in contact with
the fuel or lubricant. These could
be the pipe line transporting oil,
storage tanks, fuel pumps, bear-
ings and other places.
These prevent or at least reduce
the oxidation of oil. Oxidation rate
of oil depends mostly on tempera-
ture, oxygen, and anti-oxidant
Anti-foam Agents
Oil tends to foam when pumped
around a closed system. If exces-
sive foaming occurs the oil may
lose suction. Anti-foam agents,
which are mostly silicone com-
pounds, tend to break up foaming
of an oil. This is extremely im-
portant for oil in the hydraulic
system of a tractor because of high
pressures and heavy agitation.

1. Henderson, G. E. 1964. Selecting and Storing Tractor Fuels and Lubri-
cants. So Ass'n. for Agricultural Engineering and Vocational Agri-
culture, University of Georgia, Athens.
2. Waelti, H. and D. L. Moe. 1964. Selection of Motor Oil. Circ. 193, Ag.
Engr. Dept., So. Dakota State Univ., June 1964.

ASTM Tentative Classification D 975-53T

NO. 1-D NO. 2-D
A volatile distillate A distillate fuel oil
fuel oil for engines of low volatility for
in service requiring engines in industrial
frequent speed and and heavy mobile
load changes, service.

Water and sediment, per- max Trace 0.10
cent by volume

Carbon residue on 10 max 0.15 0.35
percent residuum, percent

Ash, percent by weight max 0.01 0.02

Distillation Temperature F
90 percent point max -675
End point max 625

Viscosity at 100 F
Kinematic centistokes min 1.4 1.8 (32.0)
(or Saybolt Universal,
sec) max -5.8 (45)

Sulfur percent by weight max 0.50 1.0

Copper strip Corrosion max No. 3 No. 3

Cetane Number min 40bc 40bc

a The numerical values contained in Table I are similar to those of corresponding grades
of commercially obtainable oil burner fuels except for addition of ash content, sulfur
limits, and cetane number. To meet special operating conditions, modifications of indi-
vidual limiting requirements may be agreed upon between purchaser, seller and supplier.

b Low-atmospheric temperatures as well as engine operation at high altitudes may require
use of fuels with higher cetane ratings.

c Where cetane number by the Cetane Method (Astm. Method D-613) is not available,
calculated Cetane Index may be used as an approximation. Where there is disagreement,
the Cetane Method (ASTM D-613) shall be the referee method.


Classification Service Conditions

"DG" No severe requirements for wear or
deposit control.
0.5% or less sulfur fuels.
"DM" Severe conditions, or using fuel which
normally promotes deposits and wear.
Engine design or operating conditions
make engine less sensitive to fuel ef-
fects, or more sensitive to residues
from oil.
0.5% or less sulfur fuels.
"DS" Engine operating under very severe
conditions or engine design character-
istics or using fuel having tendency to
produce excessive wear or deposits.
More than 0.5% sulfur in fuel


Single Multi-
Air Temp. Viscosity Viscosity
"F Grade Grade

-10" 32 SAE 10W SAE 10W-30
32 90* SAE 20W SAE 10W-30
above 90 SAE 30W SAE 20W-40

*Use Viscosity rating as recommended in the operator's manual.

(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida,
and United States Department of Agriculture, Cooperating
M. O. Watkins, Director


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