U.S. patent application number 10/893599 was filed with the patent office on 2005-02-24 for high performance non-zinc, zero phosphorus engine oils for internal combustion engines.
Invention is credited to Buck, William H., Deckman, Douglas E., Farng, L. Oscar, Givens, Willie A. JR., Jackson, Andrew.
Application Number | 20050043191 10/893599 |
Document ID | / |
Family ID | 34198252 |
Filed Date | 2005-02-24 |
United States Patent
Application |
20050043191 |
Kind Code |
A1 |
Farng, L. Oscar ; et
al. |
February 24, 2005 |
High performance non-zinc, zero phosphorus engine oils for internal
combustion engines
Abstract
A substantially zinc and phosphorous free lubricating oil
meeting engine performance requirements contain an additive system
containing metal detergents, at least one borated ashless
dispersant, at least an amine antioxidant and a trinuclear
molybdenum compound. The lubricant contains a minimum of 120 ppm
boron and a minimum of 80 ppm molybdenum.
Inventors: |
Farng, L. Oscar;
(Lawrenceville, NJ) ; Jackson, Andrew;
(Pennington, NJ) ; Givens, Willie A. JR.;
(Dumfries, VA) ; Deckman, Douglas E.; (Mullica
Hill, NJ) ; Buck, William H.; (West Chester,
PA) |
Correspondence
Address: |
ExxonMobil Research and Engineering Company
P.O. Box 900
Annandale
NJ
08801-0900
US
|
Family ID: |
34198252 |
Appl. No.: |
10/893599 |
Filed: |
July 16, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60497234 |
Aug 22, 2003 |
|
|
|
Current U.S.
Class: |
508/185 ;
508/192 |
Current CPC
Class: |
C10M 2215/065 20130101;
C10M 2207/124 20130101; C10M 2219/087 20130101; C10M 2229/02
20130101; C10M 2219/108 20130101; C10M 2207/027 20130101; C10N
2030/40 20200501; C10M 2219/044 20130101; C10M 2219/066 20130101;
C10M 2215/064 20130101; C10N 2010/04 20130101; C10N 2030/43
20200501; C10N 2040/25 20130101; C10N 2060/14 20130101; C10M
2207/021 20130101; C10N 2030/42 20200501; C10M 2215/062 20130101;
C10M 169/044 20130101; C10M 2219/08 20130101; C10M 2215/28
20130101; C10M 2227/09 20130101; C10M 161/00 20130101; C10M
2207/024 20130101; C10N 2010/12 20130101; C10M 2223/045 20130101;
C10N 2030/06 20130101; C10M 163/00 20130101 |
Class at
Publication: |
508/185 ;
508/192 |
International
Class: |
C10M 141/12 |
Claims
What is claimed is:
1. A lubricating oil composition having less than about 2000 ppm
sulfur and substantially free of zinc and phosphorus comprising:
(a) a major amount of a base oil of lubricating viscosity; and (b)
an effective amount of an additive system comprising: (i) a metal
detergent or mixture of metal detergents; (ii) an ashless
dispersant or mixture of dispersants, at least one of which is a
borated ashless dispersant; (iii) an ashless aminic antioxidant or
mixture of antioxidants containing at least an aminic antioxidant;
and (iv) an oil soluble, phosphorous free, trinuclear molybdenum
compound. (c) with the proviso that the composition have a minimum
of 120 ppm boron and a minimum of 80 ppm molybdenum.
2. The composition of claim 1 wherein the composition has a B:Mo:N
ratio in the range of about 3:5:7 to about 5:1:18.
3. The composition of claim 2 wherein the additive system includes
a mixture of alkaline metal detergents selected from the group
consisting of calcium and magnesium sulfonates, phenates,
salicylates and mixtures thereof in the amount of about 1.5 to
about 6.0 wt % based on the total weight of the composition.
4. The composition of claim 3 including a mixture of borated and
non-borated dispersants in the weight ratio of 1:9 to 9:1 and
wherein the total amount of ashless dispersant is in the range of
about 2.0 wt % to about 12.0 wt % based on the total weight of the
composition.
5. The composition of claim 4 includes a mixture of phenolic and
amine antioxidants in the weight ratio of about 1.0:9.0 to about
9.0:1.6 and wherein the total amount is in the range of about 0.25
wt % to about 2.5 wt % based on the total weight of the composition
and wherein the trinuclear molybdenum compound is present in an
amount of from about 0.05 wt % to about 1.50 wt %, based on the
total weight of the composition.
6. In the lubrication of an engine combusting a fuel containing
below about 350 ppm sulfur, the improvement wherein the engine is
lubricated with a composition comprising: (a) a major amount of a
base oil of lubricating viscosity; and (b) an effective amount of
an additive system comprising, (i) a metal detergent or mixture of
metal detergents; (ii) an ashless dispersant or mixture of
dispersants, at least one of which is a borated ashless dispersant;
(iii) an ashless aminic antioxidant or mixture of antioxidants
containing at least an aminic antioxidant; and (iv) an oil soluble,
phosphorous free, trinuclear molybdenum compound. (c) with the
proviso that the composition have a minimum of 120 ppm boron and a
minimum of 80 ppm molybdenum.
7. The improvement of claim 6 wherein the composition has a B:Mo:N
ratio in the range of about 3:5:7 to about 5:1:18.
8. The improvement of claim 7 wherein the additive system includes
a mixture of alkaline metal detergents selected from the group
consisting of calcium and magnesium sulfonates, phenates,
salicylates and mixtures thereof in the amount of about 1.5 to
about 6.0 wt % based on the total weight of the composition.
9. The improvement of claim 8 wherein including a mixture of
borated and non-borated dispersants in the weight ratio of 1:9 to
9:1 and wherein the total amount of ashless dispersant is in the
range of about 2.0 wt % to about 12.0 wt % based on the total
weight of the composition.
10. The improvement of claim 9 wherein includes a mixture of
phenolic and amine antioxidants in the weight ratio of about
1.0:9.0 to about 9.0:1.6 and wherein the total amount is in the
range of about 0.25 wt % to about 2.5 wt % based on the total
weight of the composition and wherein the trinuclear molybdenum
compound is present in an amount of from about 0.05 wt % to about
1.50 wt %, based on the total weight of the composition.
Description
[0001] This application claims the benefit of U.S. Ser. No.
60/497,234 filed Aug. 22, 2003.
FIELD OF INVENTION
[0002] The present invention is concerned broadly with lubricating
compositions and more specifically with lubricating compositions
for internal combustion engines that are substantially free of
phosphorous and zinc.
BACKGROUND OF INVENTION
[0003] Contemporary engine oil technology uses zinc
dithiophosphates (ZDTP) or more specifically zinc
dialkyldithiophosphate (ZDDP) for corrosion, oxidation and wear
protection and metallic detergents for engine cleanliness. These
additives are rich in sulfur, phosphorous and ash content, and play
a critical role in meeting severe engine performance requirements.
Unfortunately phosphorous tends to deactivate the catalysts
typically employed for control of hydrocarbon emissions from the
engine. Volatile sulfur is harmful to the catalysts used to control
NO.sub.x emissions; and, zinc contributes to plugging engine
exhaust particulate filters. Although sulfur emissions can be
reduced by formulating lubricant compositions using low sulfur base
oils as much as two thirds of the sulfur and almost all of the
phosphorous present in engine oils is due to the use of ZDTP or
ZDDP. Thus, there is a need for low sulfur containing engine oils
that are substantially free of zinc and phosphorous and yet which
do not adversely effect engine performance. Indeed there is a
further need for low sulfur, non-phosphorous, non-zinc engine oils
that are particularly suitable for use with low sulfur (<350
ppm) fuels. The present invention provides for these and other
needs.
SUMMARY OF INVENTION
[0004] In one aspect, the present invention is directed toward a
lubricating composition having low levels of sulfur, preferably
below about 2000 ppm sulfur, and substantially no zinc or
phosphorous, the composition comprising:
[0005] (a) a major amount of a base oil of lubricating viscosity;
and
[0006] (b) an additive system comprising
[0007] (i) a metal detergent or mixture of metal detergents;
[0008] (ii) an ashless dispersant or mixture of dispersants, at
least one of which is a borated ashless dispersant;
[0009] (iii) an ashless aminic antioxidant or mixture of
antioxidants containing at least an aminic antioxidant; and
[0010] (iv) an oil soluble, phosphorous free, trinuclear molybdenum
compound.
[0011] (c) with the proviso that the composition has a minimum of
120 ppm boron and a minimum of 80 ppm molybdenum.
[0012] Another aspect of the present invention is directed toward a
low sulfur containing lubricant composition which is substantially
zinc and phosphorous free that is particular suitable for use in
engines combusting low sulfur fuels, the composition comprising a
major amount of a low sulfur base oil, preferably below about 300
ppm sulfur and an additive system comprising a combination of a
metal detergent or mixture of metal detergents, at least a borated
ashless dispersant, an ashless antioxidant or mixture of
antioxidants containing at least an aminic antioxidant, and an oil
soluble, phosphorous free, trinuclear molybdenum compound, the
composition having a B:Mo:N ratio in the range of about 3:5:7 to
about 5:1:18.
[0013] The lubricants of the invention are especially useful with
fuels containing below about 350 ppm sulfur.
[0014] These and other aspects of the invention will become
apparent from the detailed description which follows.
DETAILED DESCRIPTION OF INVENTION
[0015] The lubricating compositions of the present invention will
comprise a major amount of a base oil of lubricating viscosity and
a minor but effective amount of a specific combination of
dispersants, antioxidants, detergents and antiwear agents which do
not contain zinc and phosphorous. Thus the compositions do not
include zinc and phosphorous containing additives and as such are
substantially free of zinc and phosphorous.
[0016] The base oils of the present invention will have less than
about 300 ppm sulfur. Thus suitable base oils include highly
refined Groups II and III base oils as well as Groups IV and V oils
and mixtures thereof. Preferred are Groups III, IV and V base
oils.
[0017] The additive system of the invention includes a metal
detergent or mixture of metal detergents, such as alkaline metal
detergents. Useful alkaline metal detergents are selected from
calcium and magnesium sulfonates, phenates and salicylates and
mixtures thereof.
[0018] The amount of metal detergent will constitute about 1.5 to
about 6.0 wt % based on the total weight of the composition.
Preferably the detergent will be a mixture of alkaline metal
sulfonates, and phenates and salicylates in the weight ratio of
about 25:75:0 to 0:20:80.
[0019] The additive system includes a borated ashless dispersant or
a mixture of a borated ashless dispersant and non-borated ashless
dispersants. In general, sufficient borated dispersants will be
used to provide the composition with a minimum of 120 ppm boron.
Useful borated dispersants include sulfur and phosphorous free
borated succinimides and succinic acid esters. Preferred borated
dispersants are derivatives of polyisobutylene substituted with
succinic anhydride and reacted with polyethylene amines,
polyoxyethylene amines and polyolamines (PIBSA/PAM). Useful
non-borated ashless dispersants include sulfur and phosphorous free
succinimides, carboxylic acid amides, hydrocarbyl polyamines and
the like. Preferred non-borated dispersants are based on 600
molecular weight PIB to 2800 molecular weight PIB as exemplified by
Lubrizol 6461, Lubrizol 6418, Hitec 646, Oloa 13000, ADX 222 and
the like.
[0020] In the practice of the invention it is preferred to use a
mixture of borated and non-borated ashless dispersants in the
weight ratio of 1:9 to 9:1. In any event, the total amount of
ashless dispersant used in the composition is in the range of about
2.0 wt % to about 12.0 wt % based on the total weight of the
composition.
[0021] The additive system of the invention includes an ashless
aminic antioxidant or mixture of antioxidants containing at least
an aminic antioxidant. Useful aminic antioxidants include alkylated
diphenyl amine, alkylated phenylenediamine, alkylated phenyl
alpha-naphthylamine and alkylated quinoline.
[0022] In addition to the aminic antioxidant supplementary
antioxidants may be employed. These include hindered phenols,
hindered bisphenols, sulfurized phenols, sulfurized olefins,
dithiocarbamates, phenothiazines and the like.
[0023] Typically antioxidants used in the present invention will be
a mixture of non-borated phenolic and amine antioxidants. The
weight ratio of phenol to amine is in the range of 1.0:9.0 to
9.0:1.0. The preferred antioxidant is a mixture of hindered phenols
and alkylated diphenylamines. It also is preferred that the
antioxidant be present in an amount ranging from about 0.25 wt % to
2.5 wt %, based on the total weight of the composition.
[0024] The composition of the invention includes an oil soluble,
phosphorous free trinuclear molybdenum compound. Such compounds may
be represented by the formula Mo.sub.3S.sub.kL.sub.nQ.sub.z where
the L are independently selected ligands having organo groups with
a sufficient number of carbon atoms to render the compound soluble
or dispersible in the oil, n is from 1 to 4, k varies from 4
through 7, Q is selected from the group of neutral electron
donating compounds such as water, amines, alcohols, and ethers, and
z ranges from 0 to 5 and includes non-stoichiometric values. At
least 21 total carbon atoms should be present among all the
ligands' organo groups, such as at least 25, at least 30, or at
least 35 carbon atoms. The preferred ligands are dialkyl
dithiocarbamates. In general, sufficient trinuclear molybdenum
compound is used to provide the composition with a minimum of 80
ppm molybdenum. Thus, trinuclear compound typical is present in
about 0.05 wt % to about 1.50 wt %, based on the total weight of
the composition.
[0025] Importantly, the compositions of the invention are
formulated to have a B:Mo:N ratio in the range of about 3:5:7 to
about 5:1:18.
[0026] The compositions of the invention optionally may include
other additives typically used in formulating engine oils such as
antifoamants, seal swell agents, viscosity index improvers and the
like.
[0027] The invention will be further illustrated by the following
examples.
EXAMPLE 1
[0028] A series of engine lubricants were formulated having the
compositions set forth in Table 1. Oil 1 included for comparative
purposes had a sulfur content of 3080 ppm and a phosphorous content
of 960 ppm. Oils 2 and 3 were substantially zinc and phosphorous
free and had sulfur levels of 1161 and 1483 ppm respectively.
1 TABLE 1 Oil 1 Oil 2 Oil 3 Synthetics Synthetics Synthetics
Component Viscosity Grade Formulation Chemistry 0W-40 0W-30 5W-30
Mixed Ashless Borated & non- 8 8 8 Dispersants borated PIB
succinimide/ester Mixed Ca/Mg sulfonate/ 3.35 4.3 4.3 Detergents
phenate/salicylate ZDDP Zinc 1.0 0 0 dithiophosphates Mixed
Phenolic & 1.0 1.5 1.5 Antioxidants Aminic antioxidants Mixed
Friction Moly Trimer & 0.46 0.35 0.35 Modifiers ashless
friction modifiers Mixed Silicone & non- 3.02 2.0 2.0
Defoamants/seal silicone swell agent/VI improvers Base Oil Group
IV/V Bal. Bal. Bal. Ash (D874) Wt % 0.96 0.99 1.05 Zn Ppm 1000
<5 <5 Mo Ppm 0 180 170 B Ppm 180 540 545 N Ppm (calculated)
1049 1494 1494 P Ppm 960 <5 <5 S (D2622-1) Ppm 3080 1161
1483
[0029] These oils were then subjected to the engine performance
tests listed in Table 2. The results of these tests are also
provided in that table.
2 TABLE 2 Oil 1 Oil 2 Oil 3 Engine Oil Type Synthetics Synthetics
Synthetics Viscosity Grades PAO, PAO, Group III, 0W-40 0W-30 5W-30
Special Remark Test Test Normal Low S, Low S, Method Measurement
S/P/Ash Zn/P free Zn/P free HFRR.sup.1 Ave. Friction 0.125 0.12
0.123 0.7 Kg/60 Hz/ % Ave. Film 0 96.5 81.4 0.5 mm/ Scar X/Y (mm)
0.3/0.7 .3/0.7 0.267/0.667 60 min./75.degree. C. Calc. Scar Area
0.165 0.165 0.14 Set One (mm2) HFRR.sup.1 Ave. Friction 0.096 0.089
0.096 0.5 Kg/60 Hz/ % Ave. Film 4.66 90.8 95.7 1.0 mm/ Scar X/Y
(mm) 0.3/1.28 0.3/1.23 0.28/1.2 60 min./100.degree. C. Calc. Scar
Area 0.302 0.291 0.267 Set Two (mm2) Four-Ball Wear WSD (mm) 0.47
0.40 0.38 40 Kg/1800 rpm/ K Factor 30 min./200.degree. F.
(.times.10E-8) PDSC.sup.2 Ramping @ Onset Temp 236 258.1 251.7
10.degree. C. C/min. (.degree. C.) Isothermal @ Time (min.) 10.8
16.9 16.6 220.degree. C. Hot Tube Test 1 = clean, 3 1 1 16
hr./288.degree. C. 9 = dirty Sequence IVA Cam Nose 56.9 6.7 wear
(Micron) Total Wear 305 43.8 (Micron) .sup.1HFRR = High Frequency
Reciprocating Rig .sup.2PDSC = Pressure Differential Scanning
Calorine Tray
[0030] The High Frequency Reciprocating Rig (HFRR) test results
indicate that oils 2 and 3 can lower the average friction by 1-4%
in condition set one and 0-7% in condition set two. Similarly, oils
2 and 3 can also increase film formation via electric contact
potential (ECP) measurements from 81-96% (versus 0% of oil 1) in
condition set one and 91-96% (vs. 5% of oil 1) in condition set
two. Furthermore, the calculated scar area (from the multiply of
X-axis) of oil 1 is larger than the scar area of oils 2 and 3
(0-18% larger in condition set one and 4-13% larger in condition
set two). Clearly, these results indicate the low sulfur,
phosphorus/zinc free oils protect the metal surface from wear by
forming stronger films, lowering frictional force and significantly
reducing wear better than normal S/P oil 1. These results are
correlated with Four-ball wear results very well. As the data
indicated, a reduction of wear scar diameter (WSD) from 0.467 mm
(oil 1) to 0.403 mm (oil 2) is 14% and a reduction from 0.467 mm
(oil 1) to 0.383 mm (oil 3) is 18%.
[0031] As illustrated in Table 2, very good antioxidancy is
achieved with the low sulfur, zinc/phosphorus free oils of the
invention. As shown in Pressure Differential Scanning Calorimetry
(PDSC), the onset temperature of oil 2 and oil 3 is 16-22 degrees
higher than the result of oil 1 (ramping method). Since oxidation
rates generally double with about 10.degree. C. increase in
temperature, these results can be translated into about 220% to
340% better in terms of control of viscosity or acid number
increases or any other comparable measurements for control of
oxidation. With the isothermal PDSC method, the oxidation
resistance time is about 6 minutes longer (55% better) than the
result of oil 1.
[0032] Sequence IVA testing is a very critical engine test that is
used to assess anti-wear performance of engine oils. As
demonstrated in oil 2, a low sulfur, phosphorus/zinc free oil,
passes Sequence IVA engine test (cam wear and piston cleanliness)
while oil 1 with normal sulfur/phosphorus/ash levels, fails.
Reduction in cam nose wear can be as great as 88% reduction when
compared oil 2 to oil 1 (6.7 vs. 56.9) and the reduction in total
wear is equally outstanding (86% reduction from 305 micron to 44
micron).
EXAMPLE 2
[0033] A series of zinc and phosphorus free engine lubricants were
formulated having the compositions set forth in Table 3. Oil 1 had
a boron content of 93 ppm and molybdenum content of 190 ppm whereas
oils 2 had a boron content of 540 ppm and molybdenum content of 180
ppm. Oil 3 was free of molybdenum, but had a similar boron content
to oil 2 (550 ppm). These oils were then subjected to the same
engine performance tests (Sequence IVA) set forth in Example 1 and
the results of these tests are provided in Table 3.
[0034] The Sequence IVA test results indicated that oil 2 meets
wear requirements (<120 micron) while oil 1 could not. Oil 3
also failed the engine test as molybdenum friction modifiers were
removed from the formulation. Clearly, the boron-molybdenum
synergism is needed in order to achieve a satisfactory engine
performance. Either the high boron alone or a combination of low
boron and high molybdenum is not sufficient to meet the engine
requirements.
3 TABLE 3 Oil 1 Oil 2 Oil 3 Synthetics Synthetics Synthetics
Component Viscosity Grade Formulation Chemistry 0W-30 0W-30 0W-30
Mixed Ashless Borated & non- 8 8 8 Dispersants borated PIB
succinimide/ ester and/or functionalized olefin copolymers Mixed
Ca/Mg sulfonate/ 4.3 4.3 4.3 Detergents phenate/salicylate Mixed
Phenolic & 1.5 1.5 1.5 Antioxidants Aminic antioxidants Mixed
Friction Moly Trimer 0.35 0.35 0.35 Modifiers & ashless
Defoamants/seal Silicone & 2.0 2.0 2.0 swell agent/VI
non-silicone improvers ZDDP Zinc 0 0 0 dithiophosphates Base Oil
PAO/Group V Bal. Bal. Bal. Ash (D874) Wt % 0.99 0.99 Zn Ppm <5
<5 <5 Mo Ppm 190 180 <0.5 B Ppm 93 540 550 N Ppm
(Calculated) 878 1494 1453 P Ppm <5 <5 <5 Sequence IVA 289
44 134 7-Point Total Wear (Micron)
* * * * *