U.S. patent application number 11/613015 was filed with the patent office on 2008-06-19 for lubricating oil with enhanced piston cleanliness control.
This patent application is currently assigned to Chevron Oronite Company LLC. Invention is credited to Yoshitaka Takeuchi, Jeroen Van Leeuwen.
Application Number | 20080146473 11/613015 |
Document ID | / |
Family ID | 39253964 |
Filed Date | 2008-06-19 |
United States Patent
Application |
20080146473 |
Kind Code |
A1 |
Van Leeuwen; Jeroen ; et
al. |
June 19, 2008 |
LUBRICATING OIL WITH ENHANCED PISTON CLEANLINESS CONTROL
Abstract
Provided are formulations, methods of making, and methods of
using one or more reaction products of polyisobutylenes and
monounsaturated acylating agents of the present invention in a low
sulfur, low sulfated ash, and low phosphorus lubricant to enhance
piston cleanliness in internal combustion engines.
Inventors: |
Van Leeuwen; Jeroen;
(Barendrecht, NL) ; Takeuchi; Yoshitaka;
(Shizuoka, JP) |
Correspondence
Address: |
CHEVRON CORPORATION
P.O. BOX 6006
SAN RAMON
CA
94583-0806
US
|
Assignee: |
Chevron Oronite Company LLC
|
Family ID: |
39253964 |
Appl. No.: |
11/613015 |
Filed: |
December 19, 2006 |
Current U.S.
Class: |
508/287 ;
508/110; 508/378; 508/391; 508/459; 508/460; 508/554; 508/561;
508/577; 508/579 |
Current CPC
Class: |
C10N 2040/25 20130101;
C10M 2215/064 20130101; C10N 2030/43 20200501; C10M 2207/262
20130101; C10M 2207/129 20130101; C10M 2209/084 20130101; C10M
2219/046 20130101; C10M 167/00 20130101; C10M 2207/26 20130101;
C10M 2205/022 20130101; C10N 2030/04 20130101; C10M 2223/045
20130101; C10M 2215/28 20130101; C10M 2219/089 20130101; C10M
2227/061 20130101; C10N 2040/252 20200501; C10N 2030/42 20200501;
C10M 2227/09 20130101; C10N 2040/255 20200501; C10M 2229/02
20130101; C10M 163/00 20130101; C10N 2030/45 20200501; C10M
2215/086 20130101; C10M 2207/028 20130101; C10N 2040/253 20200501;
C10M 2207/028 20130101; C10N 2010/04 20130101; C10M 2207/129
20130101; C10N 2020/04 20130101; C10M 2207/26 20130101; C10N
2010/04 20130101; C10M 2207/262 20130101; C10N 2010/04 20130101;
C10M 2215/086 20130101; C10N 2010/12 20130101; C10M 2215/28
20130101; C10M 2215/28 20130101; C10M 2215/28 20130101; C10N
2020/04 20130101; C10M 2219/046 20130101; C10N 2010/04 20130101;
C10M 2219/089 20130101; C10N 2010/04 20130101; C10M 2223/045
20130101; C10N 2010/04 20130101; C10M 2227/09 20130101; C10N
2010/12 20130101; C10M 2215/086 20130101; C10N 2010/12 20130101;
C10M 2227/09 20130101; C10N 2010/12 20130101; C10M 2207/129
20130101; C10N 2020/04 20130101; C10M 2215/28 20130101; C10N
2020/04 20130101; C10M 2207/028 20130101; C10N 2010/04 20130101;
C10M 2207/26 20130101; C10N 2010/04 20130101; C10M 2207/262
20130101; C10N 2010/04 20130101; C10M 2219/046 20130101; C10N
2010/04 20130101; C10M 2219/089 20130101; C10N 2010/04 20130101;
C10M 2223/045 20130101; C10N 2010/04 20130101 |
Class at
Publication: |
508/287 ;
508/110; 508/459; 508/579; 508/554; 508/378; 508/391; 508/460;
508/577; 508/561 |
International
Class: |
C10M 133/46 20060101
C10M133/46; C10M 169/04 20060101 C10M169/04; C10M 137/10 20060101
C10M137/10 |
Claims
1. A lubricant composition suitable for use in an internal
combustion engine, which comprises an admixture of: (a) a major
amount of an oil of lubricating viscosity; (b) one or more ashless
dispersants; (c) one or more metal-containing detergents; and (d) a
piston-cleanliness-enhancing amount of at least one reaction
product of a polyisobutylene and a monounsaturated acylating agents
wherein the polyisobutylene has a number average molecular weight
of about 200 to about 5000 Daltons; wherein said lubricant
composition has a sulfur content of at or below about 0.3 wt. %, a
phosphorus content of at or below about 0.09 wt. %, and a sulfated
ash content of at or below about 1.6 wt. %, based on the total
weight of said lubricating oil composition.
2. The lubricant composition of claim 1, wherein the reaction
product of a polyisobutylene and a monounsaturated acylating agent
is represented by either of the formulas: ##STR00005## wherein
R.sub.1 is a polyisobutylene chain with a number average molecular
weight of about 200 to about 5000 Daltons; and R.sub.2 is a
carboxyl-containing group.
3. The composition of claim 1, further comprising one or more
additives selected from: antiwear agents, friction modifiers,
antioxidants, corrosion -inhibitors, viscosity index improvers,
anti-foaming agents, seal fixes, pour point depressants, and other
multi-functional additives.
4. The composition of claim 1, wherein the sulfur content of the
composition is at or below about 0.2 wt. % based on the total
weight of said composition.
5. The composition of claim 4, wherein the sulfur content of the
composition is at or below about 0.1 wt. %, based on the total
weight of said composition.
6. The composition of claim 1, wherein the phosphorus content of
the composition is at or below about 0.08 wt. %, based on the total
weight of said composition.
7. The composition of claim 6, wherein the phosphorus content of
the composition is at or below about 0.07 wt. %, based on the total
weight of said composition.
8. The composition of claim 7, wherein the phosphorus content of
the composition is at or below about 0.05 wt. %, based on the total
weight of said composition.
9. The composition of claim 1, wherein the sulfated ash content of
the composition is at or below about 1.0 wt. %, based on the total
weight of said composition.
10. The composition of claim 9, wherein the sulfated ash content of
the composition is at or below about 0.8 wt. %, based on the total
weight of said composition.
11. The composition of claim 10, wherein the sulfated ash content
of the composition is at or below about 0.5 wt. %, based on the
total weight of said composition.
12. The composition of claim 11, wherein the sulfated ash content
of the composition is at or below about 0.45 wt. %, based on the
total weight of said composition.
13. The composition of claim 1, wherein the amount of the at least
one reaction product of a PIB and a monounsaturated acylating agent
is about 0.01 to about 5.0 wt. %, based on the total weight of the
lubricant composition.
14. The composition of claim 13, wherein the amount of the at least
one reaction product of a PIB and a monounsaturated acylating agent
is about 0.5 to about 4.0 wt. %, based on the total weight of the
lubricant composition.
15. The composition of claim 14, wherein the amount of the at least
one reaction product of a PIB arid a monounsaturated acylating
agent is about 1.0 to about 2.5 wt. %, based on the total weight of
the lubricant composition.
16. The composition of claim 1, wherein the PIB in the at least one
reaction product of a PIB and a monounsaturated acylating agent has
a number average molecular weight of about 500 to about 4500
Daltons.
17. The composition of claim 16, wherein the PIB has a number
average molecular weight of about 1000 to about 3500 Daltons.
18. The composition of claim 17, wherein the FIB has a number
average molecular weight of about 2300 Daltons.
19. The composition of claim 17, wherein the PIB has a number
average molecular weight of about 1300 Daltons.
20. The composition of claim 1, wherein the PIB in the at least one
reaction product of a PIB and a monounsaturated acylating agent is
a highly reactive PIB.
21. The composition of claim 1, wherein the monounsaturated
acylating agent is derived from an anhydride or an
anhydride-producing material.
22. The composition of claim 21, wherein the monounsaturated
acylating agent is derived from maleic anhydride.
23. The composition of claim 1, wherein the one or more
metal-containing detergents is present in an amount of about 0.05
to about 16 mM.
24. The composition of claim 1, wherein the ashless dispersant is a
bissuccinimide derived from one or more PIBSAs.
25. The composition of claim 24, wherein the ashless dispersant is
a bissucinimide derived from a PIBS A wherein the PIB chain has a
number average molecular weight of about 2300 Daltons.
26. The composition of claim 24, wherein the ashless dispersant is
a bissucinimde derived from a mixture of a first PIBSA wherein the
PIB chain has a number average molecular weight of about 2300
Daltons, and a second PIBSA wherein the PIB chain has a number
average molecular weight of about 1300Daltons.
27. The composition of claim 24, wherein the bissuccinimide is
present in an amount of about 0.5 wt. % to about 1.0 wt. %.
28. The composition of claim 3, wherein the antiwear agent is a
metal dicarbyldithiophosphate.
29. The composition of claim 28, wherein the metal
dicarbyldithiophosphate is zinc dialkylthiophosphate.
30. The composition of claim 29, wherein the amount of zinc
dialkylthiophosphate present contributes from about 0.03 to about
0.075 wt. % of phosphorus to the composition.
31. The composition of claim 1, wherein the ashless dispersant
contributes about 0.08 to about 0.12 wt. % of nitrogen to the
composition.
32. The composition of claim 1, wherein the metal-containing
detergent is a calcium overbased detergent.
33. The composition of claim 32, wherein the calcium overbased
detergent is selected from: calcium sulfonates, calcium phenates,
calcium salicylates, calcium stearates, and mixtures thereof.
34. The composition of claim 3, wherein the antioxidant is a
diphenylamine.
35. The composition of claim 34, wherein the diphenylamine is
present from about 0.05 wt. % to about 5.00 wt. %, based on the
total weight of the composition.
36. The composition of claim 3, wherein the friction modifier is a
molybdenum succinimide complex.
37. The composition of claim 36, wherein the molybdenum succinimide
complex is present in an amount of from about 0.15 to about 0.55
wt. %, based on the total weight of the composition.
38. The composition of claim 3, wherein the viscosity index
modifier is an ethylene polymer or a polyalkyl methacrylate
copolymer.
39. A method of improving piston cleanliness in an internal
combustion engine, said method comprising: operating said internal
combustion engine with, a low phosphorus, low sulfur and low
sulfated, ash lubricating oil composition, which comprises; (a) a
major amount of a base oil of lubricating viscosity; (b) one or
more ashless dispersants; (c) one or more metal-containing
detergents; and (d) a piston cleanliness-enhancing amount of at
least one reaction product of a PIB and a monounsaturated acylating
agent, wherein the PIB has a number average molecular weight of
about 200 to about 5000 Daltons; wherein said low phosphorus, low
sulfur and low sulfated ash oil composition has a sulfur content of
at or below about 0.3 wt. %, a phosphorus content of at or below
about 0.09 wt. %, and a sulfated ash content of at or below about
1.6 wt. %, based on the total weight of the composition.
40. The method according to claim 39, wherein the reaction product
of a PIB and a monounsaturated acylating agent is represented by
either of the formulas: ##STR00006## wherein R.sub.1 is a PIB chain
with a number average molecular weight of about 200 to about 5000
Daltons; and R.sub.2 is a carboxyl-containing group.
41. The method of claim 39, wherein the low phosphorus, low sulfur
and low sulfated ash lubricating oil composition further comprises
one or more additives selected from: antiwear agents, friction
modifiers, antioxidants, corrosion inhibitors, pour point
depressants, viscosity index modifiers, anti-foaming-agents, seal
fixes, arid other multi-functional additives.
42. The method of claim 39, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfur content of at or
below about 0.2 wt. %.
43. The method of claim 42, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfur content of at or
below about 0.1 wt. %.
44. The method of claim 39, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a phosphorus content of at
or below about 0.08 wt. %.
45. The method of claim 44, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a phosphorus content of at
or below about 0.07 wt. %.
46. The method of claim 45, wherein the low phosphorus, low sulfur
and low sulfated, ash oil composition has a phosphorus content of
at of below about 0.05 wt. %.
47. The method of claim 39, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfated ash content at
or below about 1.0 wt. %.
48. The method of claim 47, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfated ash content at
or below about 0.8 wt. %.
49. The method of claim 48, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfated ash content at
or below about 0.5 wt. %.
50. The method of claim 49, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfated ash content at
or below about 0.45 wt. %.
51. The method of claim 39, wherein the amount of the at least one
reaction product of a PIE and a monounsaturated acylating agent is
about 0.01 to about 5.00 wt. %, based on the total weight of the
lubricant composition.
52. The method of claim 51, wherein the amount of the at least one
reaction product of a PIB and a monounsaturated acylating agent is
about 0.50 to about 4.00 wt. %, based on the total weight of the
lubricant composition.
53. The method of claim 52, wherein the amount of the at least one
reaction product of a PIB and a monounsaturated acylating agent is
about 1.00 to about 2.50 wt. %, based on the total weight of the
lubricant composition.
54. A method of operating an internal combustion engine provided
with exhaust gas after-treatment devices, which method comprises
lubricating said engine with a lubricating, oil composition
according to claim 1.
55. A method according to claim 54, wherein said internal
combustion engine is selected from: (1) a light duty diesel-fueled
internal combustion engine; (2) a heavy duty diesel-fueled internal
combustion engine; and (3) a gasoline-fueled internal combustion
engine.
56. A method according to claim 54, wherein said exhaust gas
after-treatment devices are one or more devices selected from
particulate traps and catalytic converters.
57. A method of making a lubricant composition comprising blending
the following components: (a) a major amount of an oil of
lubricating viscosity; (b) one or more ashless dispersants; (c) one
or more metal-containing detergents; and (d) at least one reaction
product of a PIB and a monounsaturated acylating agent, wherein the
PIB has a number average molecular weight of about 200 to about
5000 Daltons; and resulting in a lubricant composition with a
sulfur content of at or below about 0.3 wt. %, a phosphorus content
of at or below about 0.09 wt. %, and a sulfated ash content of at
or below about 1.6 wt. %, based on the total weight of the
lubricant composition.
58. The method according to claim 57, wherein the reaction product
of a PIB and a monounsaturated acylating agent is represented by
either of the formulas: ##STR00007## wherein R.sub.1 is a PIB chain
with a number average molecular weight of about 200 to about 5000
Daltons; and R.sub.2 is a carboxyl-containing group.
59. The method of claim 57, where one or more additives selected
from: antiwear agents, friction modifiers, antioxidants, viscosity
index modifiers, corrosion inhibitors, anti-foaming agents, seal
fixes, pour point depressants, and other multi-functional
additives, are further blended into said lubricant composition.
60. The method of claim 57, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfur content of at or
below about 0.2 wt. %.
61. The method of claim 60, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfur content of at or
below about 0.1 wt. %.
62. The method of claim 57, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a phosphorus content of at
or below about 0.08 wt. %.
63. The method of claim 62, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a phosphorus content of at
or below about 0,07 wt. %.
64. The method of claim 63, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a phosphorus content of at
or below about 0.05 wt. %.
65. The method of claim 57, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfated ash content at
or below about 1.0 wt. %.
66. The method of claim 65, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfated ash content at
or below about 0.8 wt. %.
67. The method of claim 66, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfated ash content at
or below about 0.5 wt. %.
68. The method of claim 67, wherein the low phosphorus, low sulfur
and low sulfated ash oil composition has a sulfated ash content at
or below about 0.45 wt. %.
69. The method of claim 57, wherein the amount of the at least one
reaction product of a PIB and a monounsaturated acylating agent is
about 0.01 to about 5.00 wt. %, based on the total weight of the
lubricant composition.
70. The method of claim 69, wherein the amount of the at least one
reaction product of a PIB and a monounsaturated acylating agent is
about 0.5 to about 4.0 wt. %, based on the total weight of the
lubricant composition.
71. The method of claim 70, wherein the amount of the at least one
reaction product of a PIB and a monounsaturated acylating agent is
about 1.0 to about 2.5 wt. %, based on the total weight of the
lubricant composition.
Description
[0001] The present invention relates to lubricating oil
compositions. More specifically, the present invention relates to
lubricating oil compositions that have reduced levels of sulfated
ash, phosphorus and sulfur (low "SAPS"), yet provide improved
lubricant performance in internal combustion engines.
[0002] Environmental concerns have led to continued efforts to
reduce the emissions of carbon monoxide (CO), hydrocarbon and
nitrogen oxide (NO.sub.x) from compression-ignited (diesel-fueled)
and spark-ignited (gasoline-fueled) internal combustion engines.
There have also been continued efforts to reduce the
particulate-emissions from compression-ignited internal combustion
diesel engines. To meet the contemporary emission standards for
passenger cars and other vehicles, original equipment manufacturers
(OEMs) have been applying exhaust gas after-treatment devices. Such
exhaust gas after-treatment devices include, but are not limited
to, catalytic converters and/or particulate traps.
[0003] Catalytic converters typically contain one or more oxidation
catalysts, NO.sub.x storage catalysts, and/or NH.sub.3 reduction
catalysts. The catalysts contained therein generally comprise a
combination of catalytic metals such as platinum, and metal oxides.
Catalytic converters are installed in the exhaust systems, for
example, the exhaust pipes of automobiles, to convert the toxic
gases to nontoxic gases. The use of catalytic converters is thought
to be essential in bucking global warming trends and combating
other environmental detriments. The catalysts, however, can be
poisoned and rendered less effective, if not useless, as a result
of exposure to certain elements or compounds, especially phosphorus
compounds. Among the many ways phosphorus compounds may be
introduced into the exhaust gas is the degradation of
phosphorus-containing lubricating oil additives. Examples of
phosphorus lubricating oil additives include zinc
dialkyldithiophosphates and the like. Zinc dialkyldithiophosphates
are among the most effective and conventionally used antioxidants
and antiwear agents, from both a performance and cost-effectiveness
standpoint, in lubricating oil compositions. While they are
effective antioxidants and antiwear agents, the phosphorus, sulfur
and ash they introduce into the engine react with the catalysts and
may shorten the service life, of the catalytic converters.
Reduction catalysts are susceptible to damage by sulfur and sulfur
compounds in the exhaust gas, which are introduced by the
degradations of both the base oil used to blend the lubricants and
sulfur-containing lubricant oil additives. Examples of
sulfur-containing lubricant oil additives include, but are not
limited to, magnesium sulfonate and other sulfated or sulfonated
detergents.
[0004] Particulate traps are usually installed in the exhaust
system, especially in diesel engines, to prevent the carbon black
particles or very fine condensate particles or agglomerates thereof
(i.e., "diesel soot") from being released into the environment.
Aside from polluting air, water, and other elements of the
environment, diesel soot is a recognized carcinogen. These traps,
however, can be blocked by metallic ash which is the degradation
product of metal-containing, lubricating oil additives including
common ash-producing detergent additives.
[0005] To insure a long service life for the after-treatment
devices, it is desirable to identify lubricating oil additives that
exert a minimum negative impact on such devices. To this end, OEMs
often set various limits for maximum sulfur, phosphorus, and/or
sulfated ash levels for "new service fill" and "first fill"
lubricants. For instance, when used in light-duty passenger-car
internal combustion engines, the sulfur levels are typically
required to be at or below 0,30 wt. %, the phosphorus levels at or
below 0.08 wt. %, and the sulfated ash contents at or below 0.8 wt.
%. The maximum sulfur, phosphorus and/or sulfated ash levels may
differ, however, when the lubricating compositions are used in
heavy-duty internal combustion engines. For example, the maximum
sulfated ash level may be as high as 1.0 wt. % in those heavy-duty
engines. Such lubricating oil compositions are also referred to as
"low SAPS" (low sulfated ash, phosphorus, sulfur) lubricating oil
compositions for gasoline engines, and "LEDL" (low emission diesel
lubricant) oil compositions for diesel engines. Various tests have
been established and standardized to measure the levels of SAPS in
any particular lubricating oil compositions. For example, in
Europe, a lubricant meeting the ACEA gasoline and diesel engine low
SAPS specification must pass, inter alia, the "CEC L-78-T-99" test,
which measures the cleanliness and extent of piston ring sticking
after running a Volkswagen turbocharged direct injection automotive
diesel engine for art extended time period, cycling alternatively
between idle and full power. Similar specifications and testing
standards of varied stringencies can also be found in other
countries and regions, such as Japan, Canada, and the United
States.
[0006] Meeting the low SAPS environmental standards does not
eliminate the need to provide adequate lubricant performance.
Automobile spark ignition and diesel engines have valve train
systems, including valves, cams and rocker arms, all of which must
be lubricated and protected from wear. Further, engine oils must
provide sufficient detergency so as to insure engine cleanliness
and suppress the production of deposits, which are products of
non-combustibles and incomplete, combustibles of hydrocarbon fuels
and deterioration of engine oils.
[0007] As discussed above, the need to preserve the integrity of
catalytic converters has led to the use of less phosphate and
phosphorus-containing additives. However, the use of detergents,
which are typically metal sulfonate detergents, is often inevitable
because of the sustained needs to neutralize the oxidation-derived
acids and suspend polar oxidation residues in the lubricant. These
detergents, however, contributes to the production of sulfated ash.
Indeed, the amount of ash permitted under most of the current
environmental standards can be exceeded by far less metal sulfonate
detergent than is necessary to achieve adequate detergency
performance. Reducing the levels of detergent overbasing may reduce
the level of ash produced, but it also reduces the acid
neutralizing capacity of the lubricant composition, potentially
leading to acid corrosion of the engine pistons and other
parts.
[0008] Therefore, it would be advantageous to identify low SAPS
lubricating oil compositions and additives that not only foster
cleaner environment by allowing the catalyst converters and
particulate traps to effectively reduce pollutants, but also
improve fuel economy by, for instance, reducing friction within an
engine. A need is thus apparent for compromises or new approaches
through which both the environmental standards and the engine
lubrication needs can be satisfied.
[0009] Various low SAPS additives and lubricant compositions have
been identified as capable of providing piston cleanliness in
internal combustion engines. For example, U.S. patent application
Ser. No. 11/217,674 (published as U.S. 2006/0052254) disclosed a
low SAPS lubricant composition that provided good piston
cleanliness in an XUD-IIBTE (CEL-L-56-T-98) test. The lubricating
oil composition of this application had a sulfur content of up to
0.3 wt. %, a phosphorus content of up to 0.08 wt. %, a sulfated ash
content of up to 0.80 wt. % and contained less than 5 mmoles of
salicylate soap per kilogram of lubricating oil composition. A
companion application, U.S. patent application Ser. No. 11/218,647
(published as U.S. 2006/005820) disclosed a low SAPS lubricating
oil composition with similar advantages. That composition comprised
(a) a major amount of an oil of lubricating viscosity; (b) at least
one nitrogen-containing dispersant to provide a nitrogen content of
at least 0.075 wt. %, the dispersant having a polyalkenyl backbone
of molecular weight of about 900 to about 3000 Daltons; and (c) an
oil-soluble or oil-dispersible source of boron to provide a wt. %
ratio of nitrogen to boron of about 3:1 to about 5:1; (d) an
antioxidant; and (e) a zinc dihydrocarbyldithiophosphate. In U.S.
patent application Ser. No. 11/226,793 (published as U.S.
2006/0068999), yet another low SAPS lubricating oil composition
comprising (1) a major amount of an oil of lubricating viscosity;
(2) an overbased magnesium-containing lubricating oil detergent
having a TBN of 200 to 500 present in such an amount to provide a
TBN of 5.3 to 7.3 to the finished composition; and (3) 2.5 to 4 wt.
% of an ashless dispersant, was said to provide enhanced piston
merits.
[0010] Low SAPS lubricating oil compositions have also been known
to impart certain other desirable properties. For example, an
internal combustion engine oil of this kind was reported to retain
high total base number (TBN) in U.S. patent application Ser. No.
11/176,424 (published as U.S. 2006/0014653). The composition had a
sulfated ash content of not greater than 0.9 wt. %, and a
phosphorus content from 0.04 to 0.1 wt. %. The composition
contained base oil; one or more detergents selected from phenste
detergents, salicylate detergents, and sulphonate detergents,
wherein said one or more detergents each, independently, had a TEN
value of from 30 to 350 mg KOH/g; and at least 3.5 wt. % of one or
more antioxidants selected from the group of aminic antioxidants
and phenolic antioxidants.
[0011] In another example, U.S. patent application Ser. No.
11/288,600 (published as U.S. 2006/0116300) disclosed a low SAPS
lubricating oil composition that provided improved lubricant
performance, and especially antiwear properties, in
compression-ignited diesel engines according to a Mack T10 screener
test. That low SAPS lubricating oil composition comprised (1) a
major amount of an oil of lubricating viscosity; (2) a minor amount
of a calcium salicylate detergent; (3) a minor amount of an
overbased magnesium detergent; and (4) a minor amount of a basic,
low molecular weight nitrogen-containing dispersant derived from a
polymer having a number average molecular weight of no greater than
1100 Daltons.
[0012] It has now been found that reaction products of
polyisobutylenes and mono unsaturated acylating agents, when
accompanied by at least one ashless dispersant, at least one
metal-containing detergent, at least one antiwear additive, and at
least one antioxidant, significantly enhance piston cleanliness
control in internal combustion engines. The present invention
therefore provides a low sulfated ash, low phosphorus and low
sulfer lubricant composition, including an additive package or a
concentrate, comprising such a reaction product of a
polyisobutylene and a monounsaturated acylating agent. The present
invention also provides methods of using and making such a
lubricating oil composition.
[0013] A reaction product of a polyisobutylene and a
monounsaturated acylating agent is typically prepared from its
non-carboxylated poly isobutylene precursor. Polyisobutylenes
(PIBs) are also known as polyisobutenes to persons skilled in the
art. They have also been given the name "butyl rubber," as they are
much used in that capacity. In the lubricant and/or fuel additive
field, PIBs have found wide use as dispersants, viscosity
improvers, thickeners, and the like. The common uses for PIBs have
been summarized, far example, in section 3.3 (page 846) of Speight,
CHEMISTRY & TECHNOLOGY of PETROLEUM CHEMICAL INDUSTRIES, v. 76.
3d ed. (N.Y. Marcel Dekker. Inc., 1999); and in section 4.1 of
Immel, ULMANN'S ENCYCLOPEDIA of INDUSTRIAL CHEMISTRY (Wiley-VCH
Verlag GmbH & Go, KGaA, 2002). Useful PIBs generally contain
residual unsaturation in amounts of about one ethylene double bond
per polymer chain, positioned anywhere along the chain. Preferably,
however, the PIBs are prepared from a pure isobutylene steam or a
Raffinate I stream, resulting in a reactive isobutylene polymer
with terminal vinylidene olefins. These particular PIBs comprising
terminal vinylidene olefins are often referred to as "highly
reactive polyisobutylenes (HR-PIBs)" by those skilled in the art.
Particularly preferably, a useful HR-PIBs would have a terminal
vinylidene content of at least about 50%, for example, at least
about 55%, or at least about 65%, or at least about 70%, or at
least about 80%, or more preferably, at least about 85%, Such
HR-PIBs can Be prepared according to various art-recognized
techniques, such as, for example, those described in U.S. Pat. Nos.
4,152,499 and 4,605,808. Relevant disclosures of these patents, to
the extent they do not conflict with the disclosures and claims
herein, are incorporated by reference. Certain HR-PIBs are
commercially available, for example, under the trade name of
GLISSOPAL.TM. (from BASF.RTM.).
[0014] Reaction products of PIBs and monounsaturated acylating
agents, especially the succinic anhydride derivatives, namely, the
polyisobutylene succcinic anhydrides (PIBSAs), have been used as
precursors in manufacturing ashless dispersants. Examples of such
use can be found in U.S. Pat. Nos. 5,827,806 and 6,245,725, each
disclosing, inter alia, the making of a preferred set of
nitrogen-containing ashless dispersants from certain PIBSAs,
polyethylene amines (e.g., tetraethylene pentamine,
polyoxypropylene diamine), and aminoalcohols (e.g.,
triemethylolaminomethane).
[0015] PIBSAs have also been applied directly, i.e., without
derivatization, as dispersants. For example, U.S. Pat. No.
6,632,781 disclosed using a dispersant mixture comprising a
polyalkylene succinic dispersant selected from the group consisting
of; (1) a polyalkylene succinic anhydride, preferably a PIBSA; (2)
a non-nitrogen containing derivative of the polyalkylene succinic
anhydride; and (3) mixtures of polyalkylene succinic anhydrides;
(4) mixtures of non-nitrogen containing derivatives of the
polyalkylene succinic anhydride; and (5) mixtures of one or more
polyalkylene succinic anhydrides and one or more non-nitrogen
containing derivatives of polyalkylene succinic anhydrides. That
dispersant was said to impart enhanced water tolerance and
lubricant-oil compatibility for alkali metal borates.
[0016] The present invention provides a low sulfated ash, low
phosphorus and low sulfur lubricant composition, including an
additive package or a concentrate, comprising at least one reaction
product of a PIB and a monounsaturated acylating agent. The
lubricant additive compositions of the invention provide superior
piston cleanliness, but are also compatible for low SAPS
applications. The present invention further provides methods of
applying and making these compositions.
SUMMARY OF THE INVENTION
[0017] The present invention provides lubricating oil compositions
that provide high piston cleanliness, especially when the machines
housing those compositions operate at elevated temperatures, but
which introduce low levels of phosphorous, low levels of sulfur,
and low levels of sulfated ash to the internal combustion engines.
The levels of phosphorous in the lubricating oil compositions of
the present invention are typically at or below about 0.09 wt. %,
and preferably at or be low about 0.08 wt. %, and more preferably
at or below about 0.07 wt. %. and particularly preferably at or
below about 0.05 wt. %. The levels of sulfur produced by the
lubricating oil compositions of the present invention are typically
at m below about 0.30 wt. %, and preferably at or below about 0.20
wt. %, and particularly preferably at or below about 0.10 wt. %.
The levels of sulfated ash produced by the lubricating oil
compositions of the present invention are typically at or below
about 1.60 wt. %, but preferably at or below about 1.00 wt. %, more
preferably at or below about 0.80 wt. %, even more preferably at or
below about 0.50 wt. %, and particularly preferably at or below
about 0.45 wt. %. In one embodiment of the present invention, the
level of sulfated ash will be from above about 0,50 to about 1.60
wt. %, preferably from above about 0.5 to about 0.8 wt. %.
[0018] Therefore, the present lubricating compositions are more
desirable from an environmental standpoint than the conventional
internal combustion engine lubricating oils that contain higher
phosphorous, sulfur and sulfated ash. The compositions of the
present invention facilitate longer service lives for the catalytic
converters and the particulate traps, while providing the desired
piston cleanliness.
[0019] In a first aspect, the present lubricating oil composition
comprises;
[0020] a major amount of a base oil of lubricating viscosity;
[0021] one or more detergents;
[0022] one or more dispersants; and
[0023] a piston-cleanliness-enhancing amount of at least one
reaction product of a polyisobutylene and a monounsaturated
acylating agent, wherein the polyisobutylene has a number average
molecular weight of about 200 to about 5000 Daltons, preferably
from about 500 to about 4500 Daltons: wherein, based on the total
weight of the lubricating composition, the phosphorus content is no
more than about 0.09 wt. %; the sulfur content is no more than
about 0.3 wt. %; and the sulfated ash content is no more than about
1.6 wt. %.
[0024] The reaction product of a polyisobutylene and a
monounsaturated acylating agent may be one represented by either
Formula A or Formula B:
##STR00001##
[0025] wherein R.sub.1 is a polyisobutylene chain of number average
molecular weight of about 200 to about 5000 Daltons, preferably
from about 500 to about 4500 Daltons; and R.sub.2 is a
carboxyl-containing group.
[0026] The lubricating oil composition of this aspect may
optionally further comprise one or more additives selected from;
(1) antiwear agents; (2) friction modifiers; (3) antioxidants; (4)
corrosion inhibitors; (5) anti-foam additives; (6) seat fixes or
seal pacifiers; (7) pour point depressants; (8) viscosity index
modifiers; and (9) multifunctional additives.
[0027] In a second aspect, the invention provides an additive
package composition or a concentrate comprising at least one
reaction product of a PIB and a monounsaturated acylating agent in
an organic diluent liquid, for example, base oil. The additive
package composition or concentrate of this aspect preferably
further comprises various other additives desired in lubricating
oil, such as, for example, ashless dispersants, metal-containing
detergents, antiwear additives, antioxidants, friction modifiers,
corrosion inhibitors, anti-foam additives, pour point depressants,
viscosity index improvers, and seal fixes or seal pacifiers.
[0028] In a third aspect, the invention provides a method of
operating an internal combustion engine provided with one or more
exhaust gas after-treatment devices, which method comprises
lubricating said engine with a lubricating composition of the first
aspect, or with an additive package composition or a concentrate of
the second aspect.
[0029] In a fourth aspect, the invention provides a method of
preparing a lubricating oil composition of the first aspect or an
additive package or a concentrate of the second aspect.
[0030] Persons skilled in the art will understand other and further
objects, advantages, and features of the present invention by
reference to the following description.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Various preferred features and embodiments are described
below by way of non-limiting illustrations.
[0032] The present invention provides lubricating oil compositions
as described above. The compositions have a total sulfur content of
at or below about 0.30 wt. % in typical embodiments, at or below
about 0.20 wt. % in some other embodiments, and at or below about
0.10 wt. % in further embodiments. The major source of sulfur in
the composition of the invention is often the base stocks and the
additives. An exemplary lubricating oil composition of the present
invention contains about 0.2 wt. % of sulfur, based on the total
weight of the composition.
[0033] The lubricating oil compositions have a total phosphorus
content of at or below about 0.09 wt. % in typical embodiments, at
or below about 0,08 wt. % in some other embodiments, at or below
about 0.07 wt. % in yet other embodiments, and at or below about
0.05 wt. % in further embodiments. An exemplary lubricating oil
composition of the present invention contains about 0.07 wt. % of
phosphorus, based on the total weight of the composition.
[0034] The lubricating oil compositions have a total sulfated ash
content of, as determined by the ASTM D-874, at or below about 1.60
wt. % in typical embodiments, at or below about 1.00 wt. % in some
other embodiments, at or below about 0.80 wt. % in yet other
embodiments, at or below about 0.50 wt. % in some other
embodiments, and at or below about 0.45 wt. % in further
embodiments. An exemplary lubricating oil composition of the
present invention has a sulfated ash content of about 0.6 wt. %,
based on the weight of the lubricant compositions. Another
exemplary lubricating oil composition of the present invention has
a sulfated ash content of about 0.8 wt. %, based on the weight of
the lubricant composition.
Oil of Lubricating Viscosity
[0035] The low-SAPS lubricating oil composition of the present
invention is comprised of one or more base oils, which are present
in a major amount (i.e., an amount greater than about 50 wt. %).
Generally, the base oil is present in an amount greater than about
60 wt. %, or greater than about 70 wt. %, or greater than about 80
wt. % of the lubricating oil composition. The base oil sulfur
content is typically less than about 1.00 wt. %, preferably less
than about 0.60 wt. %, more preferably less than about 0.40 wt. %,
and particularly preferably less than about 0.30 wt. %,
[0036] The low-SAPS lubricating oil composition may have a
viscosity at 100.degree. C. of up to about 16.3 mm.sup.2/s, and in
one embodiment of about 5 to about 16.3 mm.sup.2/s (cSt), and in
one embodiment of about 6 to about 13 mm.sup.2/s (cSt). The
low-SAPS lubricating oil composition may have a
high-temperature/high-shear viscosity at 150.degree. C. as measured
by the procedure in ASTM D4683 of up to about 4 mm.sup.2/s (cSt),
and in one embodiment up to about 3.7 mm.sup.2/s (cSt), and in
another embodiment about 2 to about 4 mm.sup.2/s (cSt), and in yet
another embodiment about 2.5 to about 3.7 mm.sup.2/s (cSt), and in
one further embodiment about 2.6 to about 3.5 mm.sup.2/s (cSt).
[0037] The base oil used in the lubricant compositions of the
invention may be a natural oil, a synthetic oil, or a mixture
thereof provided that the sulfur content of such an oil does not
exceed the above-indicated sulfur concentration limit required to
sustain the low SAPS lubricating oil compositions. The natural oils
that are suitable include animal oils and vegetable oils (e.g.,
castor oil, lard oil). The natural oils may also include mineral
lubricating oils such as liquid petroleum oils and solvent-treated
or acid-treated mineral lubricating oils of the paraffinic,
naphthenic or mixed paraffinic-naphthenic types. Oils derived from
coal or shale are also useful.
[0038] Synthetic lubricating oils include hydrocarbon oils such as
polymerized and interpolymerized olefins (e.g., polybutylenes,
polypropylenes, propylene isobutylene copolymers, etc.);
poly(1-hexenes), poly-(1-octenes), poly(1-decenes), etc. and
mixtures thereof; alkylbenzenes (e.g., dodecylbenzenes,
tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)benzenes,
etc.); polyphenyls (e.g., biphenyls. terphenyls, alkylated
polyphenyls, etc.); alkylated diphenyl ethers and the derivatives,
analogs and homologs thereof, and the like. Synthetic lubricating
oils also include oils prepared by a known Fischer-Tropsch
gas-to-liquid synthetic procedure.
[0039] Another class of known synthetic lubricating oils includes
alkylene oxide polymers and interpolymers and derivatives thereof
where the terminal hydroxyl groups have been modified by a process
such as esterification or etherification. Examples of these
synthetic oils include polyoxyalkylene polymers prepared by
polymerization of ethylene oxide or propylene oxide, and the alkyl
and aryl ethers of polyoxyalkylene polymers (e.g.,
methyl-polyiso-propylene glycol ether having a molecular weight of
1000 Daltons or diphenyl ether of poly-ethylene glycol having a
molecular weight of 1000 to 1500 Daltons); and mono- and
polycarboxylic esters thereof (e.g., acetic acid esters, mixed
C.sub.3-C.sub.8 fatty acid esters, and C.sub.13 Oxo acid diester of
tetraethylene glycol).
[0040] Another suitable class of synthetic lubricating oils are the
esters of dicarboxylic acids (e.g., phthalic acid, succinic acid,
alkyl succinic acids and alkenyl succinic acids, maleic acid,
azelaic acid, suberic acid, sebasic acid, fumaric acid, adipic
acid, linoleic acid dimer, malonic acid, alkylmalonic acids,
alkenyl malonic acids) with a variety of alcohols (e.g., butyl
alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol,
ethylene glycol, diethylene glycol monoether, propylene glycol).
Specific examples of such esters includes dibutyl adipate,
di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate,
diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl
phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic
acid dimer, and the complex ester formed by reacting one mole of
sebacic acid with two moles of tetraethylene glycol and two moles
of 2-ethylhexanoic acid and the like.
[0041] Esters useful as synthetic oils also include those made from
C.sub.5 to C.sub.12 monocarboxylic acids and polyols and polyol
esters such as neopentyl glycol, trimethylolpropane,
pentaerythritol, dipentaerythritol and tripentaerythritol.
[0042] The synthetic oil can also be a poly-alpha-olefin (PAO).
Typically, the PAOs are derived from monomers having from 4 to 30,
or from 4 to 20, or from 6 to 16 carbon atoms. Examples of useful
PAOs include those derived from octene, decene, mixtures thereof,
and the like. These PAOs may have a viscosity from about 2 to about
15, or from about 3 to about 12, or from about 4 to about 8
mm.sup.2/s (cSt) at 100.degree. C. Mixtures of mineral oil with one
or more of the foregoing PAOs may be used.
[0043] Unrefined, refined and rerefined oils, either natural or
synthetic (as well as mixtures, of two or more) of the types of
oils disclosed above can be used in the lubricating compositions of
the present invention. Unrefined (or raw) oils are those obtained
directly from a natural or synthetic source without further
purification treatment. Refined oils are similar-to the unrefined
oils except they have been further treated in one or more
purification steps. Many such purification techniques are known to
those skilled in the art such as solvent extraction, secondary
distillation, acid or base extraction, filtration, percolation, and
the like. Rerefined oils are oils that have been used in service
but are subsequently treated so that they may be re-applied, in
service. Because the used oils almost always contain spent
additives and breakdown products, in addition to the standard oil
refining steps, steps that would remove the spent additives and
breakdown products must be taken. Such rerefined oils are also
known as reclaimed or reprocessed oils.
Reaction Products of a PIB & a Monounsaturated Acylating
Agent
[0044] It has been found that the incorporation of certain reaction
products of polyisobutylenes and monounsaturated acylating agents
into base oils provides low SAPS lubricating oils that have the
desired levels of piston cleanliness in internal combustion
engines. The reaction products of polyisobutylenes and
monounsaturated acylating agents of the present invention may be
represented by either Formula A or Formula B, as listed below:
##STR00002##
[0045] wherein R.sub.1 is a polyisobutylene (PIB) chain; and
R.sub.2 is a carboxyl-containing group. This new approach allows
for top tier engine performance with lower than conventional levels
of detergents and wear inhibitors.
[0046] The R.sub.1 of Formula A and/or Formula B is a PIB chain.
Suitable PIBs that many constitute the chain may be any PIBs that
have a number average weight of about 200 to about 5000 Daltons,
preferably from about 500 to about 4500 Daltons, particularly
preferably from about 1000 to about 3500 Daltons. An exemplary
lubricating oil composition of the present invention incorporates a
PIB that has a number average molecular weight of about 2300
Daltons.
[0047] The R.sub.2 of Formula A and/or Formula B is a
carboxyl-containing group derived from a monocarboxylic acid,
dicarboxylic acid, dicaxboxylic acid anhydride, anhydride-producing
material, or derivatives thereof. Such materials may include, for
example, acids, anhydrides, or acid esters. More specifically, such
materials may include one or more selected from: (1)
monounsaturated C.sub.4 to C.sub.20 dicarboxylic acids, wherein (a)
the carboxyl groups are vicinyl (i.e., located on adjacent carbon
atoms), and (b) at least one, preferably both, of said adjacent
carbon atoms are part of said mono-unsaturation; (2) derivatives of
(1) such as anhydrides and/or C.sub.1 to C.sub.10 alcohol-derived
monoesters or diesters of (1); (3) monounsaturated C.sub.3 to
C.sub.20 monocarboxylic acids wherein each of the carbon-carbon
double bonds is conjugated with the carboxyl group, i.e., is of the
structure: --C.dbd.C--CO--; and (4) derivatives of (3) such as
C.sub.1 to C.sub.10 alcohol-derived monoesters or diesters of (3).
In certain embodiments, the R.sub.2 of Formula A and/or Formula B
can also be derived from a mixture comprising any proportions of 2
or more of materials (1) to (4). Such materials are also termed
"monounsaturated acylating agents" herein. Upon reaction with the
PIB backbone, the monounsaturation of each of the monocarboxylic
acids, dicarboxylic acids, anhydrides, or derivatives thereof
becomes saturated. Thus, for example, maleic anhydride becomes
backbone substituted succinic anhydride; acrylic acid becomes
back-bone substituted propionic acid. Exemplary monounsaturated
carboxylic reactants include fumaric acid, itaconic acid, maleic
acid, maleic anhydride, chloromaleic acid, chloromaleic anhydride,
acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and
lower and intermediate alkyl (e.g., C.sub.1 to C.sub.10 alkyl) acid
esters of the foregoing. Examples of suitable alkyl acid esters
include methyl maleate, ethyl fumarate, methyl fumarate, and the
like. A particularly preferred monocarboxylic acid-, dicarboxylic
acid-, or anhydride-producing material is maleic anhydride.
Accordingly, a preferred reaction product of a PIB and a
monounsaturated acylating agent is a polyisobutylene succinic
anhydride (PIBSA).
[0048] The reaction product of a PIB and a monounsaturated
acylating agent of the present invention can be prepared by known
procedures. For example, an HR-FIB precursor of Formula A and/or
Formula B can be prepared by a cationic polymerization process, at
a temperature that is predetermined according to the desired
molecular weight for the PIB oligomer. For example, a PIB that has
an average molecular weight of about 2300 Daltons can be prepared
at a temperature of about 5.degree. F. A catalyst such as BF.sub.3
is often used to advance the polymerization. Following the
reaction, the catalyst is typically removed, for example, by
extracting the catalyst dissolved in a hot distilled water phase.
In another aspect of the polymerization process, the feed into the
reactor may include materials such as hexanes and isopropanol. The
unreacted residuals of reactive materials, including the unreacted
isobutylene monomers, are often removed or purified from the PIB
oligomers according to known methods, such as, for example, by
flashing in a flash drum and/or using an extraction column. Some
HR-PIBs are also commercially available, for example, under the
trade name of GLISSOPAL.TM. (by BASF.RTM.).
[0049] Reaction products of such HE-PIBs and monounsaturated
acylating agents can be prepared according to known methods. For
example, The succinic anhydride derivative of PIB (i.e., PIBSA) can
be prepared in accordance with methods described in U.S. Pat. Nos.
6,245,724, 6,933,351, 6,156,850, and others. To the extent they do
not conflict with the disclosures and claims herein, the relevant
contents of these patents are incorporated by reference.
Specifically, a PIBSA can be prepared using a catalyzed "thermal"
or "ene" process, wherein the polyisobutylene is reacted with
maleic anhydride at an elevated temperature in the presence of
sulfonic acid or one or more other strong-acid. This process is
capable of producing PIBSAs with a range of apparent succinic
ratios. Such ratios may be adjusted to attain the desired apparent
succinic ratios by modifying reaction parameters such as, for
example, the length of time it takes to inject the sulfonic acid or
one or more strong acids into the reactor, the maleic anhydride:PIB
charge mole ratio, and the reaction hold time. Persons skilled in
the art would understand that the apparent succinic ratio is
preferably in the range of between about 1 and about 2, preferably
between about 1.2 to about 1.6, more preferably between about 1.3
and about 1.4. Various PIBSA products can also be obtained from
commercial vendors such as Chevron Oronite Company LLC.
[0050] Suitably, the reaction products of PIBs and monounsaturated
acylating agents may be present in the lubricating oil compositions
of the present invention in an amount that is sufficient to provide
substantially enhanced piston-cleanliness and/or maintain such
cleanliness in internal combustion engines. By "substantially
enhanced," it is meant that the pistons are measurably cleaner when
assessed against standards of various countries and regions, such
as the ACEA standards in Europe and the JASO standards in Japan.
Preferably, the amount of one or more reaction products of PIBs and
monounsaturated acylating agents is about 0.01 to about 5.00 wt. %,
more preferably, about 0.50 to about 4.00 wt. %, particularly
preferably, about 1.00 wt. % to 2.50 wt. %. An exemplary
lubricating oil composition of the present invention comprised
about 2.00 wt. % of a PIBSA, wherein the PIB chain has a number
average molecular weight of about 2300 Daltons.
Metal-Containing Detergents
[0051] Metal-containing or ash-forming detergents function both as
detergents to reduce or remove deposits and as acid neutralizers or
rust inhibitors, thereby reducing wear and corrosion and extending
engine life. Detergents generally comprise a polar head with long
hydrophobic tail, with the polar head comprising a metal salt of an
acid organic compound. The composition of the present invention may
contain one or more detergents, which are normally salts, and
especially overbased salts. Overbased salts, or overbased
materials, are single phase, homogeneous Newtonian systems
characterized by a metal content in excess of that which would be
present according to the stoichiometry of the metal and the
particular acidic organic compound reacted with the metal. The
overbased materials are prepared by reacting an acidic material
(typically an inorganic acid or lower carboxylic acid, preferably
carbon dioxide) with a mixture comprising an acidic organic
compound, in a reaction medium comprising at least one inert,
organic solvent (such as mineral oil, naphtha, toluene, xylene) in
the presence of a stoichiometric excess of a metal base and a
promoter,
[0052] The acidic organic compounds useful in making the overbased
compositions of the present invention include carboxylic acids,
sulfonic acids, phosphorus-containing acids, phenols or mixtures
thereof. Preferably, the acidic organic compounds are carboxylic
acids or sulfonic acids with sulfonic or thiosulfonic groups (such
as hydrocarbyl-substituted benzenesulfonic acids), and
hydrocarbyl-substituted salicylic acids.
[0053] Carboxylate detergents, e.g., salicylates, can be prepared
by reacting an aromatic carboxylic acid with an appropriate metal
compound such as an oxide or hydroxide. Neutral or overbased
products may then be obtained by methods well known in the art. The
aromatic moiety of the aromatic carboxylic acid can contain
heteroatoms, such as nitrogen and oxygen. Preferably, the moiety
contains only carbon atoms. More preferably, the moiety contains
six or more carbon atoms, such as a benzene moiety. The aromatic
carboxylic acid may contain one or more aromatic moieties, such as
one or more benzene rings, fused or otherwise connected via
alkylene bridges. Examples of aromatic carboxylic acids include
salicylic acids and sulfurized derivatives thereof, such as
hydrocarbyl substituted salicylic acid and derivatives thereof.
Processes for sulfurizing, for example a hydrocarbyl-subtituted
salicylic acid, are known to those skilled in the art. Salicylic
acids are typically prepared by carboxylation, for example, by the
Kolbe-Schmitt process, of phenoxides. In that case, salicylic acids
are generally obtained in a diluent in admixture with
uncarboxylated phenol.
[0054] Sulfonates can be prepared by using sulfonic acid in to
sulfoniate alkyl-substituted aromatic hydrocarbons such as those
obtained from the fractionation of petroleum or those obtained from
alkylation of aromatic hydrocarbons. Alkaryl sulfonates usually
contain from about 9 to about 80 or more carbon atoms, preferably
from about 16 to about 60 carbon atoms per alkyl substituted
aromatic moiety.
[0055] Metal salts of phenols and sulfurized phenols are prepared
by reaction with an appropriate metal compound such as an oxide or
hydroxide. Neutral or overbased products may be obtained by methods
well known in the art. For example, sulfurized phenols may be
prepared by reacting a phenol with sulfur or a sulfur-containing
compound such as hydrogen sulfide, sulfur monohalide or sulfur
dihalide, to form products that are mixtures of compounds in which
2 or more phenols are bridged by sulfur-containing bridges.
[0056] The metal compounds useful in making the overbased salts are
generally any Group 1 or Group 2 metal compounds in the Periodic
Table of the Elements. The Group 1 metals of the metal compound
include Group 1a alkali metals (e.g., sodium, potassium, lithium)
as well as Group 1b metals such as copper. The Group 1 metals are
preferably sodium, potassium, lithium and copper, more preferably
sodium or potassium, and particularly preferably sodium. The Group
2 metals of the metal base include the Group 2a alkaline earth
metals (e.g., magnesium, calcium, strontium, barium) as well as the
Group 2b metals such as zinc or cadmium. Preferably the Group 2
metals are magnesium, calcium, barium, or zinc, more preferably
magnesium or calcium, particularly preferably calcium.
[0057] Examples of the overbased detergents include, but are not
limited to calcium sulfonates, calcium phenates, calcium
salicylates, calcium stearates and mixtures thereof. Overbased
detergents suitable for use with the lubricating oils of the
present invention may be low overbased (i.e., Total Base Number
(TBN) below about 100). The TBN of such a low-overbased detergent
may be from about 5 to about 50, or from about 10 to about 30, or
from about 15 to about 20. The overbased detergents suitable for
use with the lubricating oils of the present invention may
alternatively be high overbased (i.e., TBN above about 100). The
TBN of such a high-overbased detergent may be from about 150 to
about 450, or from about 200 to about 350, or from about 250 to
about 280. A low-overbased calcium sulfonate detergent with a TEN
of about 17, and a high-overbased calcium sulfurized phenate with a
TBN of about 260 are two exemplary overbased detergents in the
lubricating oil compositions of the present invention. The
lubricating oil compositions of the present invention may comprise
more than one overbased detergents, which may be all low-TBN
detergents, all high-TBN detergents, or a mix of the those two
types.
[0058] In the lubricant oil compositions of the present invention,
the amount of the overbased detergent(s), if present, may be about
0.05 to about 16 mM, or about 3 to about 15 mM, or about 4 to about
14 mM. In an exemplary embodiment of the present invention, about 4
mM of a low-TBN detergent plus about 10 mM of a high-TBN detergent
are present in the lubricating oil composition.
[0059] Suitable detergents for the lubricating oil compositions of
the present invention also include "hybrid" detergents such as, for
example, phenate/salicylates, sulfonate/phenates,
sulfonate/salicylates, sulfonates/phenates/salicylates, and the
like. Hybrid detergents have been described, for example, in U.S.
Pat. Nos. 6,153,565, 6,281,179, 6,429,178, and 6.429,179. Relevant
disclosures of these patent applications and patents, to the extent
they do not conflict with the disclosures and claims herein, are
incorporated by reference.
Ashless Dispersants
[0060] Dispersants are generally used to maintain in suspension
insoluble materials resulting, from oxidation during use, thus
preventing sludge flocculation arid precipitation or deposition on
metal parts. Nitrogen-containing ashless (metal-free) dispersants
are basic, and contribute to the TBN of a lubricating oil
composition to which they are added, without introducing additional
sulfated ash. An ashless dispersant generally comprises an oil
soluble polymeric hydrocarbon backbone having functional groups
that are capable of associating with particles to be dispersed.
Many types of ashless dispersants are known in the art.
[0061] Typical dispersants include, but are not limited to, amines,
alcohols, amides, or ester polar moieties attached to the polymer
backbones via bridging groups. The ashless dispersant of the
present invention may be, for example, selected from oil soluble
sails, esters, ammo-esters, amides, imides, and oxazolines of long
chain hydrocarbon substituted mono and dicarboxylic acids or their
anhydrides; thiocarboxylate derivatives of long chain hydrocarbons,
long chain aliphatic hydrocarbons having a polyamine attached
directly thereto; and Mannich condensation products formed by
condensing a long chain substituted phenol with, formaldehyde and
polyalkylene polyamine.
[0062] "Carboxylic dispersants" are reaction products of carboxylic
acylating agents (acids, anhydrides, esters, etc;) comprising at
least 34 and preferably at least 54 carbon atoms with nitrogen
containing compounds (such as amines), organic hydroxy compounds
(such as aliphatic compounds including monohydric and polyhydric
alcohols, or aromatic compounds including phenols and naphthols),
and/or basic inorganic materials. These reaction products include
imides, amides, and esters.
[0063] Succinimide dispersants are a type of carboxylic
dispersants. They are produced by reacting hydrocarbyl-substituted
succinic acylating agent with organic hydroxy compounds, or with
amines comprising at least one hydrogen atom attached to a nitrogen
atom, or with a mixture of the hydroxy compounds and amines. The
term "succinic acylating agent" refers to a hydrocarbon-substituted
succinic acid or a succinic acid-producing compound, the latter
encompasses the acid itself. Such materials typically include
hydrocarbyl-substituted succinic acids, anhydrides, esters
(including half esters) and halides.
[0064] Succinic-based dispersants have a wide variety of chemical
structures, which may be represented by the formula:
##STR00003##
wherein each R.sub.1 is independently a hydrocarbyl group, such as
a polyolefin-derived group. Typically the hydrocarbyl group is an
alkyl group, such as a polyisobutyl group. Alternatively expressed,
the R.sub.1 groups can contain about 40 to about 500 carbon atoms,
and these atoms may be present in aliphatic forms. R.sub.2 is an
alkylene group, commonly an ethylene (C.sub.2H.sub.4) group.
Succinimide dispersants have been more folly described in, for
example, U.S. Pat. Nos. 4,234,435, 3,172,892 and 6,165,235.
Relevant disclosures of these patents, to the extend they do not
conflict with the disclosures herein, are incorporated by
reference.
[0065] The polyalkenes from which the substituent groups are
derived are typically homopolymers and interpolymers of
polymerizable olefin monomers of 2 to 16 carbon atoms, and usually
2 to 6 carbon atoms. The amines which are reacted with the succinic
acylating agents to form the carboxylic dispersant composition can
be monoamines or polyamines.
[0066] Succinimide dispersants are referred to as such since they
normally contains nitrogen largely in the form of imide
functionality, although the amide functionality may be m the form
of amine salts, amides, imidazolines as well as mixtures thereof.
To prepare a succinimide dispersant, one or more succinic
acid-producing compounds and one or more amines are heated and
typically water is removed, optionally in the presence of a
normally liquid and substantially inert organic liquid
solvent/diluent. The reaction temperature is generally in the range
of about 80.degree. C. up to the decomposition temperature of the
mixture or the product, which typically falls between about
100.degree. C. and about 30.degree. C. Additional details and
examples of the procedures for preparing the succinimide
dispersants of the present invention have been described in, for
example, U.S. Pat. Nos. 3,172,892, 3,219,666, 3,272,746, 4,234,435,
6,440,905 and 6,165,235. Relevant disclosures of these patents, to
the extend they do not conflict with the disclosures herein, are
incorporated by reference.
[0067] Suitable ashless dispersants may also include amine
dispersants, which are reaction products of relatively high
molecular weight aliphatic halides and amines, preferably
polyalkylene polyamines. Examples thereof have been described, for
example, in U.S. Pat. Nos. 3,275,554, 3,438,757, 3,454,555,
3,565,804, and the like. Relevant disclosures of these patents, to
the extend they do not conflict with the disclosures herein, are
also incorporated by reference.
[0068] Suitable ashless dispersants may further include "Mannich
dispersants," which are reaction products of alkyl phenols in which
the alkyl group contains at least 30 carbon atoms with aldehydes
(especially formaldehyde) and amines (especially polyalkylene
polyamines). These dispersants have been described, for example, in
U.S. Pat. Nos. 3,036,003, 3,586,629, 3,591,598, 3,980,569, and the
like. Relevant disclosures of these patents, to the extent they do
not conflict with the disclosures and claims herein, are likewise
incorporated by reference.
[0069] Suitable ashless dispersants may even include post-treated
dispersants, which are obtained by reacting carboxylic, amine or
Mannich dispersants with reagents such as dimercaptothiazoles,
urea, thiourea, carbon disulfide, aldehydes, ketones, carboxylic
acids, hydrocarbon-substituted succinic anhydrides, nitrile
epoxides, boron compounds and the like. Post-treated dispersants
have been described, for example, in U.S. Pat. Nos. 3,329,658,
3,449,250, 3,666,730, aid the like. Relevant disclosures of these
patents, to the extent they do not conflict with the disclosures
and claims herein, are further incorporated by reference.
[0070] Suitable ashless dispersants may be polymeric, which are
interpolymers of oil-solubilizing monomers such as decyl
methacrylate, vinyl decyl ether and high molecular weight olefins
with monomers containing polar substitutes. Polymeric dispersants
have been described, for example, in U.S. Pat. Nos. 3,329,658,
3,449,250, 3,666,730, and the like. Relevant disclosures of these
patents, to the extent they do not conflict with the disclosures
and claims herein, are similarly incorporated by reference,
[0071] In an exemplary lubricating oil composition of the present
invention, a bissuccinimide treated with ethylene carbonate was
used as the ashless dispersant. The dispersant(s) of the present
Invention are preferably non-polymeric (e.g., are mono- or
bissuccinimides).
[0072] The ashless dispersant is suitably present in an amount of
about 0.5 to about 10.0 wt. %, preferably about 3.0 to about 7.0
wt. %. An exemplary lubricating oil composition of the present
invention comprises an ethylene-carbonate treated bissuccinimide
dispersant derived from a PIBSA wherein the PIB chain has a number
average molecular weight of about 2300 Daltons (PIBSA 2300) In an
amount of about 6.5 wt. %. Another lubricating oil composition of
the present invention comprises a similar dispersant in an amount
of about 6.0 wt. %, in combination with another borated
bissuccinimide derived from another PIBS A wherein the PIB chain
has a number average molecular weight of about 1300 Daltons (PIBSA
1300). Preferably, the lubricating oil composition comprises from
about 0.01 to about 0.35 wt. %, preferably from about 0.05 to about
0.25 wt. %, particularly preferably from about 0.08 to about 0.1.2
wt. % of total nitrogen from dispersant.
Other Additives
[0073] The lubricating oil compositions of the present invention
may optionally comprise various other additives, including, but not
limited to, antiwear agents, friction modifiers, antioxidants,
corrosion inhibitors, viscosity index improvers, and other
additives commonly used to lubricate internal combustion
engines.
Antiwear Agents
[0074] Dihydrocarbyl dithiophosphate metal salts are frequently
used as antiwear and antioxidant agents. The metal may be an alkali
or alkaline earth metal, or aluminum, lead, tin, molybdenum,
manganese, nickel or copper. The zinc salts are the most commonly
used in lubricating oil in amounts of about 0.1 to about 10 wt. %,
preferably about 0.2 to about 2 wt. %, based upon the total weight
of the lubricating oil composition. They may be prepared in
accordance with known techniques by first forming a dihydrocarbyl
dithiophosphoric acid (DDPA), usually by reaction of one or more
alcohol or a phenol with P.sub.2S.sub.5 and then neutralizing the
formed DDPA with a zinc compound. For example, a dithiophosphoric
acid may be made by reacting mixtures of primary and secondary
alcohols. Alternatively, multiple dithiophosphoric acids can he
prepared where the hydrocarbyl groups on one are entirely secondary
in character and the hydrocarbyl groups on the others are entirely
primary in character. To make the zinc salt, any basic or neutral
zinc compound could be used but the oxides, hydroxides and
carbonates are most often employed. Commercial additives frequently
contain an excess of zinc due to the use of an excess of the basic
zinc compound in the neutralization reaction.
[0075] The preferred oil-soluble zinc dialkyldithiophosphates may
be produced from dialkykyldithiophosphoric acids of the
formula:
##STR00004##
The hydroxyl alkyl compounds from which the dialkyldithiophosphoric
acids are derived can be represented generically by the formula ROH
or R'OH, wherein R or R' is alkyl or substituted alkyl, preferably
branched or non-branched alkyl containing 3 to 30 carbon atoms.
More preferably, R or R' is a branched or non-branched alkyl
containing 3 to 8 carbon atoms.
[0076] Mixtures of hydroxyl alkyl compounds may also be used. These
hydroxyl alkyl compounds need not be monohydroxy alkyl compounds.
The dialkyldithiophosphoric acids may thus be prepared from mono-,
di-, tri-, tetra-, and other polyhydroxy alkyl compounds, or
mixtures of two or more of the foregoing. Preferably, the zinc
dialkyldithiophosphate derived from only primary alkyl alcohols is
derived from a single primary alcohol. Preferably, that single
primary alcohol is 2-ethylhexanol. Preferably, the zinc
dialkyldithiophosphate derived from only secondary alkyl alcohols.
Preferably, that mixture of secondary alcohols is a mixture of
2-butanol and 4-methyl-2-pentanol.
[0077] The phosphorus pentasulfide reactant used In the
dialkyldithiophosphoric acid formation step may contain minor
amounts of any one Or more of P.sub.2S.sub.3, P.sub.4S.sub.3,
P.sub.4S.sub.7, or P.sub.4S.sub.9, Compositions as such may also
contain minor amounts of free sulfur.
[0078] Although the lubricating oil compositions of the present
invention are capable of providing excellent antiwear performance
in the presence of amounts of zinc dialkyldithiophosphate providing
greater amounts of phosphorus, the improved performance of the
inventive lubricating oil compositions are particular apparent in
low SAPS formulations which, by definition, have phosphorus levels
of no greater than about 0.08 wt. %. Therefore, lubricating oil
compositions of the present invention contains less than about 0.08
wt. % of phosphorus, more preferably from about 0.03 to about 0.075
wt. % of phosphorus. An. exemplary lubricating oil composition of
the present invention comprises about 11.5 mM zinc
dialkyldithiophosphate.
Viscosity Index Modifiers
[0079] The viscosity index of the base stock is increased, or
improved, by incorporating therein, certain polymeric materials
that function as viscosity modifiers (VM) or viscosity index
improvers (VII). Generally, polymeric materials useful as viscosity
modifiers are those having number average molecular weights (Mn) of
from about 5,000 to about 250,000, preferably from about 15,000 to
about 200,000, more preferably from about 20,000 to 150,000
Daltons. These viscosity modifiers can optionally be grafted with
grafting materials such as, for example, maleic anhydride, and the
grafted material can be reacted with, for example, amines, amides,
nitrogen-containing heterocyclic compounds or alcohol, to form
multifunctional viscosity modifiers (dispersant-viscosity
modifiers).
[0080] Exemplary lubricating oil compositions of the present
invention employ various polyalkyl methacrylate copolymers, which
may or may not be grafted by maleic anhydride. The copolymers may
be employed at an amount from about 0.1 to about 10 wt. % of the
lubricating oil composition.
Friction Modifiers
[0081] Lubricating oil compositions of the present invention
further comprise a sulfur-containing molybdenum compound. Certain
sulfur-containing organo-molybdenum compounds are known to function
as friction modifiers in lubricating oil compositions, while also
providing antioxidant and antiwear credits to a lubricating oil
composition. Examples of such oil soluble organo-molybdenum
compounds include dithiocarbamates, dithiophosphates,
dithiophosphinates, xanthates, thioxanthates, sulfides, and the
like, and mixtures thereof.
[0082] Oil-soluble or dispersible trinuclear molybdenum compounds
can be prepared by reacting in the appropriate liquid(s)/solvent(s)
a molybdenum source such as
(NH.sub.4).sub.2Mo.sub.3S.sub.13n(H.sub.2O), where n varies between
0and 2 and includes non-stoichiometric values, with a suitable
ligand source such as a tetralkylthiuram disulfide. Other
oil-soluble or dispersible trinuclear molybdenum compounds can be
formed during a reaction in the appropriate solvent(s) of a
molybdenum source, such as of
(NH.sub.4).sub.2Mo.sub.3S.sub.13.n(H.sub.2O)s a ligand source such
as tetralkylthiuram disulfide, dialkyldithiocarbamate, or
dialkyldithiophosphate, and a sulfur-abstracting agent such as
cyanide ions, sulfite ions, or substituted phosphines.
Alternatively, a trinuclear molybdenum-sulfur halide salt such as
[M'].sub.2[MO.sub.3S.sub.7A.sub.6], where M' is a counter ion, and
A is a halogen such as Cl, Br, or I, may be reacted with a ligand
source such as a dialkyldithiocarbamate or dialkyldithiophosphate
in the appropriate liquid(s)/solvent(s) to form an oil-soluble or
dispersible trinuclear molybdenum compound. The appropriate
liquid/solvent may be, for example, aqueous or organic.
[0083] The terms "oil-soluble" or "dispersible" used herein do not
necessarily indicate that the compounds or additives are soluble,
dissolvable, miscible, or capable of being suspended in the oil in
all proportions. These do mean, however, that they are, for
instance, soluble or stably dispersible in oil to an extent
sufficient to exert their intended effect in the environment in
which the oil is employed. Moreover, the additional incorporation
of other additives may also permit incorporation of higher levels
of a particular additive, if desired.
[0084] An exemplary lubricating oil composition of the present
invention employs a molybdenum succinimide complex as friction
modifier. Of the lubricating oil composition, the molybdenum
complex may constitute from about 0.15 to about 0.55 wt. %,
preferably from about 0.28 to about 0.45 wt. %.
Antioxidants
[0085] Oxidation inhibitors or antioxidants reduce the tendency of
mineral oils to deteriorate in service. Such oxidation inhibitors
include hindered phenols, alkaline earth metal salts of
alkylphenolthioesters having preferably C.sub.5 to C.sub.12 alkyl
side chains, calcium nonylphenol sulfide, oil soluble phenates and
sulfurized phenates, phosphosulfurized or sulfurized hydrocarbons
or esters, phosphorous esters, metal thiocarbamates, oil soluble
copper compounds as described in, for example, U.S. Pat. No.
4,867,890.
[0086] Aromatic amines having at least two aromatic groups attached
directly to the nitrogen constitute another class of compounds that
is frequently used for antioxidancy. Typical oil soluble aromatic
amines having at least two aromatic groups attached directly to one
amine nitrogen contain from 6 to 16 carbon atoms. The amines may
contain more than two aromatic groups. The aromatic rings are often
substituted by one or more substituents selected from, for example,
alkyl, cycloalkyl, alkoxy, aryloxy, acyl, acylamino, hydroxy, and
nitro groups.
[0087] Lubricating oil compositions in accordance with the present
invention preferably contain from about 0.05 to about 5,00 wt. %,
more preferably from about 0.10 to about 3.00 wt. %. and
particularly preferably from about 0.20 to about 0.80 wt. % of
phenolic antioxidant, aminic antioxidant, or a combination thereof,
based on the total weight of the lubricating oil composition. An
exemplary lubricating oil composition of the present invention
comprises about 0.40 wt. % of an antioxidant that is
di-C.sub.8-diphenylamine. Another exemplary lubricating oil
composition of the present invention comprises about 0.30 wt. % of
a dinonyl diphenylamine as an antioxidant.
[0088] Additional additives may be incorporated into the
compositions of the invention to satisfy the particular performance
requirements associated with low SAPS applications in internal
combustion engines. Examples of such other additives include, for
example, rust inhibitors, anti-foaming agents, and seal fixes or
seal pacifiers.
[0089] Rust inhibitor or anti corrosion agents may be a nonionic
polyoxyethylene surface active agent. Nonionic polyoxyethylene
surface active agents include, but are not limited to,
polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ether,
polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl
ether, polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl
ether, polyoxyethylene sorbitol monostearate, polyoxyethylene
sorbitol mono-oleate, and polyethylene glycol monooleate. Rust
inhibitors or anticorrosion agents may also be other compounds,
which include, for example, stearic acid and other fatty acids,
dicarboxylic acids, metal soaps, fatty acid amine salts, metal
salts of heavy sulfonic acid, partial carboxylic acid ester of
polyhydric alcohols, and phosphoric esters. An exemplary
lubricating oil composition of the present invention comprises a
calcium stearate salt.
[0090] Foam inhibitors typically include alkyl methacrylate
polymers and dimethyl silicone polymers. Exemplary compositions of
the present invention contain silicon-based foam inhibitors in
amounts ranging from about 5 to about 40 ppm, preferably from about
8 to about 35 ppm, more preferably from about 10 to about 25 ppm,
based on the total weight of the composition.
[0091] Seal fixes are also termed seal swelling agents or seal
pacifiers. They are often employed in lubricant or additive
compositions to insure proper elastomer sealing, and prevent
premature seal failures and leakages. Seal swell agents may be, for
example, oil-soluble, saturated, aliphatic, or aromatic hydrocarbon
esters such as di-2-ethylhexylphthalate, mineral oils with
aliphatic alcohols such as tridecyl alcohol, triphosphate ester in
combination with a hydrocarbonyl-substituted phenol, and
di-2-ethylhexylsebacate.
[0092] Some of the above-mentioned additives can provide a
multiplicity of effects; thus for example, a single additive may
act as a dispersant as well as an oxidation inhibitor. These
multifunctional additives are well known.
[0093] When lubricating compositions contain one or more of the
above-mentioned additives, each additive is typically blended into
the base oil in an amount that enables the additive to provide its
desired function, it may be desirable, although not essential, to
prepare one or more additive concentrates comprising additives
(concentrates sometimes being referred to as additive packages)
whereby several additives can be added simultaneously to the oil to
form me lubricating oil composition. The final composition may
employ from about 5 to about 30 wt. %, preferably about 5 to about
25 wt. %, typically about 10 to about 20 wt. % of the concentrate,
the remainder being the oil of lubricating viscosity. The
components can be blended in any order and can be blended as
combinations of components.
[0094] This invention will be further understood by reference to
the following examples, which are not to be considered as
limitative of its scope.
EXAMPLES
[0095] The following examples are provided to illustrate the
present invention without limiting it. While the present invention
has been described with reference to specific embodiments, this
application is intended to encompass those various changes and
substitutions that may be made by those skilled in the art without
departing from the spirit and scope of the appended claims.
Example 1
[0096] Oil A was prepared and tested for piston cleanliness and
tendency to piston ring sticking according to the Volkswagen
Turbocharged DI test, a European passenger car diesel engine test
(CEL-L-78-T-99), which is part of the ACEA B specification
promulgated by the European Automobile Manufacturers Association in
2004. This test was used to simulate repeated cycles of high-speed
operation followed by idling. A Volkswagen 1.9 liter, inline,
four-cylinder turbocharged direct injection automotive diesel
engine (VW TDi) was mounted on an engine dynamometer stand. A
54-hour, 2-phased procedure that cycles between 30 minutes of
40.degree. C. oil sump at idle and 150 minutes of 145.degree. C.
oil sump at full power (4150 rpm) was carried out without interim
oil top-ups. After the procedure, the pistons were rated for carbon
and lacquer deposits, as well for groove carbon filling. The piston
rings were evaluated for ring sticking. The piston cleanliness and
ring sticking of VW TDi engine tests were also carried out with
Comparative Example Oil B. The results are given in Table 1.
[0097] Oil A shows a distinct and surprising improvement over
Comparative Oil B in the VW TDi piston cleanliness and ring
sticking test.
[0098] Oil A: A lubricating oil composition was prepared comprising
about 1.50 wt. % of a polyisobutylene succinic anhydride derived
from a polyisobutylene having a number average molecular weight of
about 2300 Daltons, an ethylene carbonate-treated bissuccinimide
dispersant, a low-overbased calcium sulfonate detergent, an
overbased sulfurized and carbonated calcium phenate, a zinc
dihydrocarbyl dithiophosphate, a moly succinimide, a
di-C.sub.8-diphenylamine antioxidant, a silicon-based foam
inhibitor, an ethylene polymer, a rust inhibitor, and mineral oil
base stocks. Oil A had a sulfated ash content of about 0.78 wt. %,
nitrogen content of about 0.092 wt. %, sulfur content of about
0.183 wt. %, and phosphorus content of about 0.071 wt. %.
[0099] Comparative Example Oil B: the formulation of Oil A was
duplicated except that Oil B does not contain PIBS A 2300. Oil B
had a sulfated ash content of about 0.78 wt. %, nitrogen content of
about 0.092 wt. %, sulfur content of 0.183 wt. %, and phosphorus
content of 0.071 wt. %.
TABLE-US-00001 TABLE 1 Test type: VWTD12 SAE: 5W30 Components Oil A
Oil B PIBSA 2300 1.50 wt. % None Bissuccinimide dispersant 6.50 wt.
% 6.50 wt. % Low-TBN calcium sulfonate 4 mM 4 mM Calcium Stearate
35 mM 35 mM High-TBN sulfurized & 10 mM 10 mM carbonated
calcium phenate 11.5 mM 11.5 mM Zinc dialkyldithiophosphate 0.37
wt. % 0.37 wt. % Moly succinimide 0.40 wt. % 0.40 wt. %
Di-C.sub.H-diphenylamine 25 ppm 25 ppm Silicon-based foam inhibitor
0.84 wt. % 0.82 wt. % Ethylene polymer 0.71 wt. % 0.71 wt. %
Diluent Oil Length of test 54 hours 54 hours P-MER AVG:
G1-3&L1&2 63 57 PClnRL206Avg 66 66 VW Lmt-PCLN Combnd AV 67
67 AvRStk (8R-4P) ASF (0 10) 0.62 0.93 MxRStk (1 Rg) ASF (0 10) 2.5
5 Grvs, 1st RStk, AV, ASF 1.25 1.88 Grvs, 1st RStk, MX, ASF 2.5 5
Grvs, 2nd RStk, MX, ASF 0 0 # of Rings with ASF >= 2.5 3 3
Scoring (*) Pass ACEA B4 Fail ACEA B4 & B5 or B5
[0100] The pass/fail score according to the ACE A standards B4 and
B5 are listed in the following Table 1.1;
TABLE-US-00002 [0100] TABLE 1.1 ACEA B4 limits ACEA B5 limits P-MER
Avg 63 (.gtoreq.RL206-3) 66 (.gtoreq.RL206) # Rngs w/ASF
.gtoreq.2.5 .ltoreq.1.2 .ltoreq.1.2 Grvs, 1st RStk, MX, ASF
.ltoreq.2.5 .ltoreq.2.5 Grvs, 2nd Rstk, MX, ASF .ltoreq.0.0
.ltoreq.0.0
Example 2
[0101] Oil C was prepared and tested for piston cleanliness and
tendency to piston ring sticking according to the Volkswagen
Turbocharged DI test described above. The Piston cleanliness and
ring sticking of VW TDi engine tests were also carried out with
Comparative Example Oil D. The results are given in Table 3. The
results were scored against the more stringent Japanese piston
cleanliness standards (JASO C2 test standards), wherein the P-MER
AVG has a minimum value of 65.
[0102] Oil C shows a distinct and surprising improvement over
Comparative Oil D In the VW TDi piston cleanliness and ring
sticking test.
[0103] Oil C: A lubricating oil composition was prepared comprising
about 2.00 wt. % of a succinic anhydride derivative of
polyisobutylene having a number average molecular weight of about
2300, an ethylene carbonate-treated bissuccinimide dispersant that
is a mixture of one derived from PIBSA 2300 and another derived
from PIBSA 1300(i.e., the polyisobutylene precursor had a number
average molecular weight of about 1300 Daltons), a low-overbased
calcium sulfonate detergent, an overbased sulfurized and carbonated
calcium phenate, a mixture of primary and secondary zinc
dihydrocarbyl dithiophospbate, a moly succinimide, a triborate wear
inhibitor, a viscosity improver, a di-C.sub.8-diphenylamine
antioxidant, a silicon-based foam inhibitor, and mineral oil base
stocks. Oil C had a sulfated ash content of about 0.59 wt. %,
nitrogen content of about 0.113 wt. %, sulfur content of about
0.213 wt. %, and phosphorus content of 0.074 wt. %.
[0104] Comparative Example Oil D: The formulation of Oil C was
duplicated except that Oil F did not contain PIBSA 2300. Oil D has
a sulfated ash content of about 0.59 wt. %, nitrogen content of
about 0.113 wt. %, sulfur content of 0.213 wt. %, and phosphorus
content of 0,074 wt. %.
TABLE-US-00003 TABLE 3 Test: VWTDI2 SAF: 0W30 Components Oil C Oil
D PIBSA 2300 2.00 wt. % None Bissuccinimide dispersant derived from
6.00 wt. % 6.00 wt. % PIBSA 2300 1.80 wt. % 1.80 wt. %
Bissuccinimide dispersant derived from 7.5 mM 7.5 mM PIBSA 1300
17.5 mM 17.5 mM Low-TBN calcium sulfonate 12.0 mM 12.0 mM High-TBN
sulfurized and carbonated 0.30 wt. % 0.30 wt. % calcium phenate
0.30 wt. % 0.30 wt. % 1.degree. and 2.degree. Zinc
dialkyldithiophosphate mix 10 ppm 10 ppm Moly succinimide 0.20 wt.
% 0.20 wt. % Dinonyl diphenylamine 5.80 wt. % 7.0 wt. %
Silicon-based foam inhibitor 0.71 wt. % 0.71 wt. % Triborate
wear/oxidation inhibitor Viscosity improver polymer Diluent Oil
Length of rest 54 hours 54 hours P-MER AVG: G1-3&L1&2 73 65
PCInRL148Avg 62 62 PCInRL206Avg 65 65 VW Lmt-PCLN Combnd AV 66 66
AvRStk (8R-4P) ASF (0 10) 0 0 Grvs, 1st RStk, MX, ASF 0 0 Grvs. 2nd
RStk, MX, ASF 0 0 # of Rings with ASF >= 2.5 0 0 Scoring(**)
Pass JASO C2 Borderline pass JASO C2 (**)The pass/fail scores were
given according to the JASO piston cleanliness standard C2
* * * * *