1 . . . . , ,
CA 02370525 2001-12-03
SPECIFICATION
FUEL OIL COMPOSITION FOR DIESEL ENGINE
FIELD OF THE INVENTION
This invention relates to a new fuel oil composition for diesel engines, more
particularly the composition characterized. by base stock which contains a
specific
content of normal paraffin compounds having a carbon number of 20 or more, has
a
specific carbon number distribution in the high-boiling normal paraffin
compounds,
contains a specific content of polynuclear aromatic hydrocarbon compounds and
sulfur at O.OSwt.% or less, and is incorporated with a flow improver and
lubricity
improver.
BACKGROUND OF THE INVENTION
Diesel engines are widely used for various purposes, e.g., for driving
automobiles, ships and construction machines, and are still spreading further.
As a
result, fuel for diesel engines is increasingly in demand, and becoming
heavier to
satisfy the increased demands, because straight-run diesel fuel oil is
distilled deeper
and/or blended with heavier fractions. This is accompanied by several
problems,
e.g., deteriorated fluidity at low temperature (i.e., increased pour point
and/or cold
flow plugging point). It is anticipated, therefore, that several engine
troubles, e.g.,
clogging of fuel passage or fuel filter, may occur in a normal temperature
range at
which the engine is operated in some districts. The other concerns are
increased
nitrogen oxide and particulate matter emissions, which further aggravate
environmental pollution.
Several measures against deteriorated fluidity of diesel fuel oils at low
temperature have been proposed to provide fuel oils having adequate pour point
and
cold flow plugging point (CFPP) properties for temperature conditions, in
particular
in cold districts. These measures include limitation on end point of straight-
run
diesel oil, limitation on use of heavier fractions as the blending stocks, use
of lighter
. . ' . , . .
CA 02370525 2001-12-03
blending stocks, and use of adequate additives, e.g., fluidity improver,
including
pour point depressant and flow improver (FI), to improve fluidity at low
temperature. For example, Japanese Laid-open Patent Application No. 8-157839
discloses fuel oil composition characterized by base stock which contains
normal
paraffin compounds at 1 Swt.% or less, normal paraffin compounds having a
carbon
number of 20 or more at l.2wt% or less, and sulfur at O.lSwt.% or less, as the
composition serviceable in cold districts, high in density, sufficiently low
in pour
point and allowing the engine to produce a high power.
Japanese Laid-open Patent Application No. 7-331261 discloses a diesel fuel oil
composition composed of diesel oil having an end point in a range from 320 to
340°C, incorporated with 0.1 to 2.0 vol.% of a fraction containing
normal paraffin
compounds having a carbon number of 26 to 31 and 100 to 600 ppm of an ethylene
vinyl acetate-based additive to improve fluidity at low temperature. This
composition is aimed at abatement of particulate emissions from a diesel
engine and
improvement of low-temperature fluidity, measured by CFPP.
Limitation on end point of straight-run diesel oil and limitation on use of
heavier
fractions as the blending stocks to secure low-temperature fluidity of diesel
fuel oils
provide a good pour point, but are difficult to provide a good CFPP. Moreover,
these approaches little contribute to increasing diesel fuel oil supplies.
Blending
diesel fuel oil with a lighter fraction decreases flash point and also
decreases engine
output. Use of an additive, such as pour point depressant or FI, involves some
problems. For example, a pour point depressant, although decreasing pour
point,
will not decrease CFPP. An FI, on the other hand, although generally
decreasing
pour point and CFPP, may not efficiently decrease CFPP, depending on type of
stock
for base stock which constitutes diesel fuel oil or distillation properties of
base
stock.
The techniques to abate emissions, e.g., nitrogen oxides and particulate
matter,
CA 023705252001-12-03
from diesel engines have been also developed from various angles. These
include
improvement of combustion chamber shapes, installation of exhaust gas recycle
(EGR) systems, exhaust gas cleani~.g-up catalytic converters and particulate
matter
collectors, and improvement of diesel fuel oils and lubricants. None of these,
however, brings satisfactory results in terms of abatement effect; economic
efficiency or stability for extended periods. An EGR system, which is
considered to
be one of efficient means, recycles part of exhaust gases into the combustion
air
stream. However, this approach causes various problems, e.g., decreased
durability
and reliability of the engine, deterioration of the lubricant, increased
particulate
matter emissions and decreased engine output, because exhaust gases contain
sulfate
ions and particulate matter. These problems will be further aggravated, when
an
EGR system is installed for a direct injection diesel engine which is required
to
operate under a high load. Sulfate ions are derived from sulfur contained in
diesel
fuel oil, and low-sulfur diesel fuel oil containing sulfur at O.OSwt.% or less
has now
become a social need.
Sulfur contained in a diesel fuel oil can be reduced by refining, in
particular
catalytic hydrogenation, of the base stock. This, however, is accompanied by
decreased lubricity of diesel fuel oil itself, and will damage the injection
device of
the engine. It is known that wear of the injection pump notably increases as
sulfur
content decreases from 0.2wt.%.
Improving fuel oil quality has been attracting attention as an effective means
to
abate pollutant emissions, because it needs essentially no engine
modification. For
example, Japanese Laid-open Patent Application No. 8-225789 discloses diesel
fuel
which contains sulfur at 0.05 wt.% or less, benzothiophene at 30 W.ppm or more
as
sulfur, and polynuclear aromatic hydrocarbon compounds having 3 rings or more
at
0.2 to 1.4 W.%, and this diesel fuel further containing indoles at 13 wt.ppm
or less
as nitrogen. It is claimed that these fuel oils satisfy the environmental
requirement
for low sulfur content and exhibit sufficient lubricity without using an
additive, e.g.,
3
CA 02370525 2001-12-03
friction modifier.
Japanese Laid-open Patent Application No. 8-291292 discloses a diesel fuel oil
composition which contains sulfur at 0.01 to O.OSwt.%, and (A) an ester of a
nitrogen compound having hydroxide group and straight-chain saturated fatty
acid,
and (B) 15 to 2000 mg/L of at least one type of polymer selected from the
group
consisting of the polymers from monomers of olefin compounds, ethylenic
unsaturated alkyl carboxylates and saturated aliphatic vinyl compounds. It is
claimed that this composition exhibits good lubricity in spite of very low
sulfur
content, improved low-temperature fluidity and no deterioration of exhaust
gases
without causing troubles at the fuel injection pump in the diesel engine.
These prior-art techniques, however, give diesel fuel oils insu~cient in low-
temperature fluidity, abatement of pollutant emissions and lubricity, and are
also
economically unsatisfactory. Therefore, they can rarely give diesel fuel oil
compositions showing good CFPP and lubricity, while efficiently controlling
pollutant emissions (in particular, particulate matter) and containing sulfur
at
O.OSwt.% or less.
It is an object of the present invention to provide a diesel fuel oil
composition
efficiently controlling pollutant emissions, showing good CFPP and lubricity,
and
containing sulfur at O.OSwt.% or less by improving the prior-art techniques.
SUMMARY OF THE INVENTION
The applicants of the present invention have extensively studied the effects
of
normal paraffin content, carbon number distribution of the normal paraffin
compounds and polynuclear aromatic hydrocarbon compound content on low-
temperature fluidity and lubricity of the diesel fuel oil incorporated with an
FI and
lubricity improver and also on quantity of particulate matter (PM) emissions
exhausted when it is combusted, for diesel fuel base stock containing sulfur
at
4
CA 0237052552001-12-03
O.OSwt.% or less, to find that PM emissions are greatly reduced and good CFPP
and.
lubricity can be secured when the base stock containing sulfur at O.OSwt.% or
less
satisfies the relationships of 0 <A 4 . 00 (wherein, A is content (wt.%),
based on
total normal para~n compounds present in the base stock, of normal paraf~m
compounds having a carbon number of 20 or more), 0.04 [B / C ] 0. 4 0
(wherein, B
is content (wt.%) of normal paraffin compounds having a carbon number of (n +
5),
C is content (wt.%) of normal paraffin compounds having a carbon number of
(n);
[B/C] is average B/C ratio; and (n) is a positive integer when total content
of normal
paraffin compounds having a carbon number of (n) or more is 3.0 wt.% or less
and
closest thereto, based on the total normal paraffin compounds in the base
stock), and
0 <D 8.0 (wherein, D is content (vol.%), based on the whole base stock, of
polynuclear aromatic hydrocarbon compounds), and is incorporated with 0.01 to
O.lOwt.% (as the active component) of an FI and 0.002 to O.lwt.% (as the
active
component) of a lubricity improver, reaching the present invention.
That is, the present invention provides a diesel fuel oil composition
characterized
by base stock satisfying the relationships 0 <A 4. 0 0 (wt.%), 0.04 [B/ C ]
0.4 0 and
0 <D 8.0 (vol.%), containing sulfur at O.OSwt.% or less, and being
incorporated
with 0.01 to O.lOwt.% of an FI and 0.002 to O.lwt.% of a lubricity improver.
The present invention, relating to the above diesel fuel oil composition,
includes
the following preferred embodiments:
( 1 ) the diesel fuel oil composition composed of a base stock having a [B/C]
ratio
of 0.07 to 0.20,
(2) the diesel fuel oil composition composed of a base stock having a D value
of
0 to 5.0 vol.%,
(3) the diesel fuel oil composition of ( 1 ), wherein said base stock has a D
value
of 0 to 5.0 vol.%,
(4) the diesel fuel oil composition of ( 1 ), wherein active ingredient of the
FI is at
CA 02370525 2001-12-03
least one type of compounds selected from the group consisting of ethylene
glycol ester-based compounds and ethylene-vinyl acetate-based copolymers,
(5) the diesel fuel oil composition of one of (1) to (3), wherein active
ingredient
of the FI is at least one type of compounds selected from the group consisting
of ethylene glycol ester-based compounds and ethylene-vinyl acetate-based
copolymers,
(6) the diesel fuel oil composition, wherein content of the active component
for
the FI is 0.03 to 0.07wt.%,
(7) the diesel fuel oil composition of one of ( 1 ) to (5), wherein content of
the
active component for the FI is 0.03 to 0.07wt.%,
(8) the diesel fuel oil composition, wherein the active component for the
lubricity
improver is an ester-based compound,
(9) the diesel fuel oil composition of one of (1) to (7), wherein the active
component for the lubricity improver is an ester-based compound,
(10) the diesel fuel oil composition, wherein content of the active component
for
the lubricity improver is 0.005 to O.OSwt.%, and
( 11 ) the diesel fuel oil composition of one of ( 1 ) to (9), wherein content
of the
active component for the lubricity improver is 0.005 to O.OSwt.%.
the present invention provides a fuel oil composition for diesel engines which
efficiently controls PM emissions and exhibits good CFPP and lubricity by
incorporating a base stock satisfying the relationships 0 <A 4. 0 0 (wt.%),
0.04
[B/C] 0.40 and 0 <D 8 .0 and containing sulfur at O.OSwt.% or less with an
adequate FI and Iubricity improver.
Detailed Descr~tion of the Invention
The present invention is described below in detail. The diesel fuel oil
composition of the present invention is characterized by base stock which has
the
component A, [B/C] ratio and component D in specific ranges, contains sulfur
at
O.OSwt.% or less, and is incorporated with 0.01 to 0. l Owt.% of an FI and
0.002 to
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CA 02370525 2001-12-03
O.lwt.% of a lubricity improver.
The base~stock for the present invention mainly comprises a mineral oil,
having a
flash point of 40°C or higher and 90% distillation temperature of
360°C or lower.
The mineral oil for the present invention is a petroleum fraction, including a
petroleum fraction obtained by atmospheric distillation of crude oil, and
petroleum
fraction obtained by atmospheric or vacuum distillation of crude oil and
refined by
an adequate process, e.g., hydrogenation, hydrocracking, catalytic cracking
and a
combination thereof. These petroleum fractions can be used individually or in
combination. The base stock component other than petroleum fraction includes
vegetable oil, e.g., soybean, coconut and rape oil, and animal oil, e.g.,
whale and fish
oil.
The diesel fuel oil composition of the present invention is composed of a base
stock which satisfies the relationship 0 <A 4 . 00 (wt.%) (wherein, A is
content,
based on all normal paraffin compounds present in the base stock, of normal
parafrin
compounds having a carbon number of 20 or more). When A is above 4.OOwt.%,
the normal paraffin compounds may separate out as ambient temperature
decreases,
to cause problems, e.g., clogging of the fuel passage or fuel filter in the
diesel
engine.
The diesel fuel oil composition of the present invention is also composed of a
base stock which satisfies the relationship 0.04 [B / C ] 0. 4 0, preferably
0.07
[B/C] 0.20 (wherein, B is content (wt.%) of normal para~n compounds having a
carbon number of (n + 5), C is content (wt.%) of normal paraffin compounds
having
a carbon number of (n), [B/C] is average B/C ratio, and (n) is a positive
integer
when total content of normal paraffin compounds having a carbon number of (n)
or
more is 3.0 wt.% or less and closest thereto, based on the total normal
paraffin
compounds in the base stock. Assuming that the component A in the base stock
accounts for 3.Owt.% of the total normal paraffin components of the base
stock, the
7
CA 02370525 2001-12-03
average of the (n-C25)/(n-C2o), (n-C26)/(n-C2~), (n-Cz~)/(n-C22) ~ ~ ~ ~
ratios
consecutively calculated is in a range from 0.04 to 0.40, inclusive. When
[B/C] is
below 0.04, some of the normal paraffin compounds in the base stock may
separate
out as large planar crystals as ambient temperature decreases, even when the
relationship 0 <A 4.00 (wt.%) is satisfied, to easily cause plugging of the
fuel filter.
In other words, such a base stock has an excessively high CFPP The similar
troubles will occur, when [B/C] exceeds 0.40.
The diesel fuel oil composition of the present invention is also composed of a
base stock which satisfies the relationship 0 <D 8 . 0 (vol.%), preferably 0
<D
5.0, more preferably 0 <D 3 .0 (wherein, D is content (vol.%), based on the
whole
base stock, of polynuclear aromatic hydrocarbon compounds). When D exceeds 8.0
vol.%, PM content in the exhaust gases may increase to an unacceptable level.
Normally, a base stock contains aromatic hydrocarbon compounds at 20 to 40
vol.%;
single-ring aromatic hydrocarbon compounds at 12 to 30 vol.% and polynuclear
aromatic hydrocarbon compounds (having two or more rings) at 2 to 15 vol.%.
Therefore, the fuel oil composition of the present invention for diesel
engines
shows a good CFPP, even when ambient temperature decreases, when its base
stock
satisfies the relationships 0 <A 4 . 00 (wt.%), 0.04 [B / C ] 0. 4 0 and 0 <D
8. 0
(vol.%).
The component A of the base stock for the present invention can be selected
from adequate petroleum fractions of different normal paraffin content. These
petroleum fractions include petroleum fractions obtained by atmospheric
distillation
of crude of varying normal paraffin content, and petroleum fractions obtained
by
atmospheric or vacuum distillation of crude and refined by an adequate
process, e.g.,
solvent dewaxing and catalytic dewaxing. [B/C] of the base stock can be
adjusted
by controlling extent of rectification for the distillation operation. [B/C)
increases as
extent of rectification decreases, and so is vice versa. The component D of
the base
8
CA 02370525 2001-12-03
stock can be adjusted by adequately blending petroleum fractions of varying
polynuclear aromatic hydrocarbon content or petroleum fractions whose
polynuclear
aromatic hydrocarbon content is adjusted by an adequate process, e.g., solvent
extraction or hydrogenation. Content of polynuclear aromatic hydrocarbon
compounds can be determined by the method proposed by Japanese Petroleum
Institute (JPI-SS-49-97, based on HPLC). The above petroleum fractions can be
used individually or in combination to adjust A, [B/C] and D levels for the
base
stock for the present invention.
The FI useful for the present invention can be selected from the known ones.
These include ethylene glycol ester-based compounds, ethylene-vinyl acetate
copolymers, ethylene alkylacrylate-based copolymers, chlorinated polyethylene,
polyalkyl acrylate, alkenyl succinamide-based compounds. The preferable ones
are
an ethylene glycol ester-based compound and/or ethylene-vinyl acetate
copolymer.
An FI dosage below O.Olwt.% may not satisfactorily decrease CFPP, and above
O.lwt.% is not economical, because CFPP will not decrease as much as increased
dosage. The preferable FI dosage is 0.03 to 0.07wt.%. The above FI's may be
used
individually or in combination.
The lubricity improver useful for the present invention can be selected from
the
known ones. These include a fatty acid, e.g., stearic, linolic and oleic acid,
and
ester, e.g., those of the above fatty acid and polyalcohol, e.g., glycerin.
The
preferable one is an ester. A lubricity improver dosage below 0.002W.% may not
satisfactorily improve lubricity, and above O.lwt.% is not economical, because
lubricity will not be improved as much as increased dosage. The preferable
lubricity
improver dosage is 0.005 to O.OSW.%. The above lubricity improvers may be used
individually or in combination.
The fuel oil composition of the present invention for diesel engines may be
incorporated with other known additives for fuel oil, so long as its
performance is
9
CA 02370525 2001-12-03
not damaged. These additives include cetane improver, antioxidant, metal
deactivator, detergent, corrosion inhibitor, pour point depressant, de-icer,
bactericide, combustion promoter, antistatic agent, and coloring agent. A
general
dosage of the additive is 0.1 to O.Swt.% in the case of pour point depressant,
although not limited to this level. One or more of these additives may be used
for
the present invention, as required.
The diesel fuel oil composition of the present invention may be also
incorporated
with one or more types of oxygenated compounds so long as its performance is
not
damaged. These compounds include aliphatic alcohols, e.g., methanol, ethanol,
isopropanol, n-butanol, isobutanol, tert-butanol, amyl alcohol, isoamyl
alcohol, n-
octanol, 2-ethyl hexanol, n-heptyl alcohol, tridecyl alcohol, cyclohexanol and
methyl cyclohexanol; ethers, e.g., methyl tert-butyl ether and ethyl tert-
butyl ether;
dialkyl phthalates, e.g., diethyl phthalate, dipropyl phthalate and dibutyl
phthalate;
glycol-ether compounds, e.g., ethylene glycol monoisobutyl ether, diethylene
glycol
mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol
dimethyl ether, triethylene glycol mono-n-butyl ether, triethylene glycol
dimethyl
ether, propylene glycol monomethyl ether acetate and dipropylene glycol mono-n-
butyl ether; hydroxyl amine compounds; and diketones, e.g., acetyl acetone. A
general dosage of the oxygenated compound is 1 to 1 Swt.%, although not
limited to
this level.
The present invention is described in more detail by EXAMPLES, below, which
by no means limit the present invention. The following base stocks, FI's and
lubricity improver were used for EXAMPLES and COMPARATIVE EXAMPLES.
Measurements of CFPP, A, [B/C] and D are also described.
( 1 ) Base stock
A total of 19 types of base stocks (A to S) were used. Their properties are
given
in Tables 1 and 3.
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Table 1
* wt%
Base
stock
A B C D E F G H
Density(g/cm 0.83690.83380.82480.84610.83900.84570.83700.8365
)
Flash point(C) 70 68 69 69 71 75 73 75
Distillation
(C)
Initial boiling176.0 182.0 161.5 224.0 186.0 215.0 208.0 216.0
point
10% 222.5 220.5 212.5 260.0 233.5 257.0 248.0 254.0
SO% 287.5 279.0 279.0 294.0 281.5 292.0 287.0 287.0
90% 346.0 345.0 342.5 340.0 345.0 336.0 334.0 330.0
End point 376.5 377.0 374.0 365.0 378.0 357.0 357.0 353.0
Sulfur content*0.04 0.05 0.03 0.04 0.03 0.04 0.04 0.03
Cloud point(C) -4 -3 -4 -2 1 0 1 1
CFPP(C) -S -4 -4 -3 0 -2 0 -2
Pour point(C) -7.5 -5 -7.5 -2.5 0 -2.5 0 0
A(~%) 2.78 3.03 2.82 3.05 4.52 3.30 3.45 3.80
0.092 0.089 0.089 0.054 0.027 0.035 0.434 0.045
D(vol%) 3.7 2.7 4.7 7.8 4.8 4.9 4.0 4.5
11
CA 02370525 2001-12-03
Table 2
* wt%
Base
stock
I J K L M N O P
Density(g/cm')0.83650.83770.83500.83690.84030.84250.81390.8255
Flash point(C)72 70 68 69 69 71 75 7
Distillation(C)
Initial boiling205.0 171.0 175.0 172.0 146.5139.0 194.5 167.0
point
10% 245.0 230.5 228.5 230.0 218.0222.0 225.5 228.0
50% 285.0 280.0 278.5 279.5 276.0280.0 265.5 273.0
90% 348.0 343.0 345.5 344.0 334.0334.5 312.0 324.0
End point 379.0 372.0 376.0 373.0 361.5361.0 329.0 346.0
Sulfur content*0.03 0.03 0.03 0.03 0.03 0.03 0.02 0.02
Cloud point(C)2 _2 -2 -2 -1 -1 -5 -4
CFPP(C) 1 -3 -3 -3 -3 -3 -6 -5
Pour point(C) 0 -5 -5 -5 -5 -5 -7.5 -5
A(wt%) 3.30 1.06 0.92 1.02 3.61 3.92 0.90 1.57
[B/C]
0.050 0.354 0.154 0.248 0.0860.100 0 0
D(vol%)
10.2 3.2 2.3 4.5 5.3 7.5 2.1 3.8
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Table 3
Base
stock
Q R S
Density(g/cm 0.83550.83480.8355
)
Flash point(C)75 72 73
Distillation(C)
Initial boiling170.0 172.5 170.5
point
10% 230.0 232.5 230.5
SO% 280.0 281.5 282.0
90% 346.0 350.0 351.0
End point 376.0 375.0 377.0
Sulfur content*0.03 0.03 0.03
Cloud point(C)_1 0 0
CFPP(C) _2 -2 -1
Pour point(C) -2,5 -2.5 -2.5
A(wt%) 3.35 4.72 3.85
0.460 0.320 0.350
D(vol%)
5.1 7.8 10.5
(2) FI's
* Wt%
An ethylene glycol ester-based FI (ECA9911 produced by EXXON Chemical)
and ethylene-vinyl acetate-based FI (PF240, produced by EXXON Chemical) were
used.
13
CA 02370525 2001-12-03
(3) Lubricity improver
A lubricity improver with ester-based compound as the active ingredient
(PDN655, produced by EXXON Chemical) was used.
(4) Measurement of CFPP
CFPP was measured as per JIS K-2288.
(5) Measurement of "A"
Content of an individual normal paraffin compound in each base stock was
measured by gas chromatography using an analyzer (GC-6AM, produced by
Shimadzu), where each sample was passed through a capillary column (inner
diameter: 0.25mm, length: 15m, impregnated with methyl silicon to a thickness
of
0.1 Vim) at 50 to 350°C. "A" is defined as total content of normal
paraffin
compounds having a carbon number of 20 or more.
(6) Measurement of [B/C]
[B/C] was determined by the following procedure. Content of an individual
normal paraffin compound in each base stock was measured by gas
chromatography.
Content of the normal paraffin compound having the largest carbon number, and
contents of the normal paraffin compounds having smaller carbon numbers are
calculated consecutively, where (n) is defined as the number of carbon when
total
content of normal paraffin compounds having a carbon number of (n) or more is
3.0
wt.% or less and closest thereto, based on the total normal paraffin compounds
in the
base stock. Next, (content of normal paraffin compounds having a carbon number
of (n+5))/(content of normal paraffin compounds having a carbon number of (n))
ratios are calculated consecutively, and the average is taken as [B/C]. The
same gas
chromatography as that for measurement of "A" was used.
(7) Measurement of "D"
Content of polynuclear aromatic hydrocarbon compounds were determined by
14
CA 02370525 2001-12-03
the method proposed by Japanese Petroleum Institute (JPI-5 S-49-97, based on
HPLC). "D" was defined as total content of polynuclear aromatic hydrocarbon
compounds having 2 rings and those having 3 rings or more.
EXAMPLES and COMPARATIVE EXAMPLES
The base stocks shown in Tables 1 to 3 were used to prepare the fuel oil
compositions shown in Tables 4 to 7, to measure CFPP levels and lubricity of
these
compositions (prepared by EXAMPLES 1 to 9 and COMPARATIVE EXAMPLES 1
to 13), and quantities of PM emissions exhausted when they were combusted. The
results are given in Tables 4 to 7. Methods to determine lubricity and PM
emissions
are described later.
CA 02370525 2001-12-03
Table 4
EXAMPLES
1 2 3 4
Fuel oil compositions(wt%)
Base stock A 99.95
Base stock B 99.95
Base stock C 99.948
B ase stock D 99.95
FI(ECA 9911) 0.04 0.04 0.04 0.04
FI(PF 240) - _ _ -
Lubricity improver 0.010 0.010 0.012 0.010
Properties of base
fuel
Sulfur content(wt%)
0.04 0.05 0.03 0.04
%)
2.78 3.03 2.82 3.05
[BBC]
0.092 0.089 0.089 0.054
D(vol%)
3.7 2.7 4.7 7.8
CFPP (C) of fuel oil
(a) Fuel oil (incorporated
with no
-5 -4 -4 -3
F1)
-16 -13 -14 -9
(b)Fuel oil (incorporated
with an
11 9 10 6
FI)
(c)Decreased CFPP [(a)-(b)]
Lubricity of fuel oil 416 411 418 421
Size of wear-caused
scar (um)
PM emissions in exhaust0.076 0.060 0.083 0.110
gases
P M (g/l:m)
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Table 5
EXAMPL ES
5 6 7 8 9
Fuel oil compositions(wt%)
Base stock J gg.g7
Base stock K gg,g7
Base stock L 99.97
B ase stock M
99.968
B ase stock N
gg.g7
FI(ECA 9911)
FI(PF 240) 0.02 0.02 0.02 0.02 0.02
Lubricity improver
0.01 0.01 0.01 0.012 0.01
Properties of base fuel
Sulfur content(wt%)
0.03 0.03 0.03 0.03 0.03
%)
1.06 0.92 1.02 3.61 3.92
[B/C)
0.354 0.154 0.2480.086 0.100
D(vol%)
3.2 2.3 4.5 5.3 7
5
CFPP (C) of fuel oil .
(a) Fuel oil (incorporated
with no FI)
-3 -3 -3 -3 -3
(b)Fuel oil (incorporated
with an FI)
(c)Decreased CFPP [(a)-(b)]-12 -12 -12 -11 -9
Lubricity of fuel oil 9 g 9 8 6
Size of wear-caused scar
(pm)
PM emissions in exhaust 410 _ 408 415 421 416
gases
PM (g/km)
0.072 0.061 0.0850.09 0.12
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CA 02370525 2001-12-03
Table 6
COM PARATIVE PLES
EXAM .
1 2 3 4 5 6'
Fuel oil compositions(wt%)
Base stock A 99.96
Base stock E 99.91
Base stock F 99,90
B ase stock G 99.953
B ase stock H
99.92
B ase stock I
99.95
FI(ECA 9911)
0.04 0.04 0.04 - 0.04 0.04
FI(PF 240)
Lubricity improver
0.05 0.06 0.007 0.08 - 0.01
Properties of base fuel
Sulfur content(wt%)
0.03 0.04 0.04 0.03 0.04 0.03
A(wt%)
4.52 3.30 3.45 3.80 2.78 3
30
[B/C]
.
D(vol%) 0.027 0.035 0.434 0.045 0.0920.050
4.8 4.9 4.0 4.5 3.7 1 0.2
CFPP (C) of fuel oil
(a) Fuel oil (incorporated
with no FI)
(b)Fuel oil (incorporated0 -2 0 -2 -5 -3
with an FI)
(c)Decreased CFPP [(a)-(b)]-1 -3 0 -2 -15 -10
Lubricity of fuel oil 1 1 0 0 10 7
Size of wear-caused
scar (pm)
PM emissions in exhaust403 410 406 418 580 415
gases
P M (g/km)
0.088 0.086 0.080 0.082 0.0700.250
18
CA 02370525 2001-12-03
Table 7
COMPARATIVE
EXAMPLES
'1 8 9 10 11 12 13
Fuel oil compositions(wt%)
Base stock J 99.99 99.98
Base stock O 99.90
Base stock P . , 99.968
B ase stock Q 99.973
B ase stock R
99.93
B ase stock S
99.97
FI(ECA 9911)
FI(PF 240)
- 0.02 0.02 0.02 0.02 0.02 0.02
Lubricity improver
0.01 - 0.08 0.012 0.007 0.05 0.01
Properties of base fuel
Sulfur content(wt%)
0.03 0.03 0.02 0.02 0.03 0.03 0.03
A(wt%)
1.06 1.06 0.90 1.57 3.35 4.72 3
85
[B/C] .
0.354 0.354 0 0 0.460 0.320 0
350
D(vol%) .
3.2 3.2 2.1 3.8 5.1 7.8 1 0.5
CFPP (C) of fuel oil
(a) Fuel oil (incorporated
with no FI)
(b)Fuel oil (incorporated-3 -3 -6 -5 -2 -2 -1
with an FI)
(c)Decreased CFPP [(a)-(b)]-4 -12 -7 -6 -3 -3 -9
Lubricity of fuel oil 1 9 1 1 1 1 8
Size of wear-caused
scar (um)
PM emissions in exhaust425 552 401 418 428 406 401
gases
P M (g/km)
0.071 0.075 0.062 0.078 0.09 0.11 0.28
19
CA 02370525 2001-12-03
( 1 ) Measurement of lubricity
Lubricity was assessed by resistance of fuel oil to wear. Resistance to wear
was
measured as per JPI-55-50-97 (gas oil/lubricant oil testing method). Size of
the
wear-caused scar (gym) was determined using a high frequency reciprocating rig
(HFRR, produced by PCS) under the conditions shown in Table 8. Size of the
scar
increases as lubricity of fuel oil decreases.
Table 8
Liquid quantity 2 t 0.20m1
Stroke 1 t 0 03mm
Frequency 50 t 1 Hz
Liquid temperature 40 t 2°C or 60 t 2°C
Load 200 t 1 gf
Testing time 75 t 0. 1 min
Liquid surface area 6 t 1 cm2
(2) Measurement of PM emissions
PM emissions in the exhaust gases were determined as per the ''diesel ~~ehicle
10-15 mode exhaust gas testing method (TRIAS-24-4-1993).
(a) Test engine and conditions
The test engine and conditions are given in Tables 9 and 10.
CA 02370525 2001-12-03
Table 9
Engine type IDI (Toyota Corolla)
Inner cylinder diameter 86. 0 x 85. 0
and stroke (mm)
Number of cylinders 4
Total displacement 1974
Compression ratio 23
Max. Output (PS/rpm) 73/4700
Table 10
Fuel oil temperature (C), 25 .0
Outlet temperature of cooling 80
water (C),
(Lubricant temperature g0
(C},
Intake air temperature 2512
(C),
Intake air humidity (RH 5015
%)
(b) Collection and measurement of PM
The exhaust gases were directed from the exhaust pipe to a dilution tunnel
system (Horiba Seisakusho), to measure PM emissions (glkm).
As shown in Tables 4 and 5, the fuel oil composition exhibits a notable low
CFPP of -9 to -16°C, when it comprises a base stock which has the
component A,
[B/C] ratio and component D in specific ranges, contains sulfur at O.OSwt.% or
less,
and is incorporated with an adequate FI and lubricity improver. Its CFPP is
significantly lower than that of the base stock by 6 to 11°C. It
notably controls PM
emissions. It also has high resistance to wear, showing a wear-caused scar of
408 to
421~m. By contrast, the compositions prepared by COMPARATIVE EXAMPLES
21
. ,
CA 02370525 2001-12-03
shown in Tables 6 and 7, which fail to satisfy the relationship with respect
to A or .
[B/C], has a CFPP value high and virtually unchanged from that of the base
stock,
even when incorporated with an FI and lubricity improver (COMPARATIVE
EXAMPLES 1 to 3 and 9 to 12). It is also found that a fuel oil composition
shows
insufficient CFPP, essentially on a level with that of the base stock, in the
absence of
FI, even when its base stock has the component A, [B/C] ratio and component D
in
specific ranges (COMPARATIVE EXAMPLES 4 and 7). Similarly, a fuel oil
composition shows notably low lubricity in the absence of lubricity improver,
even
when its base stock has the component A, [B/C] ratio and component D in
specific
ranges (COMPARATIVE EXAMPLES 5 and 8). Moreover, a fuel oil composition
gives, when combusted, a notably large quantity of PM emissions, when its base
stock has the component D out of the specific range, even when it has the
component A and [B/C] ratio in specific ranges, and is incorporated with FI
and
lubricity improver. It is therefore essential for a fuel oil composition for
diesel
engines to comprise a base stock which has the component A, [B/C) ratio and
component D in specific ranges, contains sulfur at O.OSwt.% or less, and is
incorporated with an adequate FI and lubricity improver, in order to
efficiently
control PM emissions and exhibit good CFPP and lubricity.
22
