U.S. patent application number 16/176161 was filed with the patent office on 2019-06-06 for method for preventing or reducing low speed pre-ignition.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Raymond G. Burns, III, Smruti A. Dance, Douglas E. Deckman, Jordan C. Smith.
Application Number | 20190169524 16/176161 |
Document ID | / |
Family ID | 64427214 |
Filed Date | 2019-06-06 |
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United States Patent
Application |
20190169524 |
Kind Code |
A1 |
Smith; Jordan C. ; et
al. |
June 6, 2019 |
METHOD FOR PREVENTING OR REDUCING LOW SPEED PRE-IGNITION
Abstract
A method for preventing or reducing low speed pre-ignition in an
engine lubricated with a lubricating oil by using as the
lubricating oil a formulated oil. The formulated oil has a
composition including a lubricating oil base stock as a major
component, and at least one lubricating oil additive, as a minor
component. The lubricating oil contains at least one metal or
metalloid in an amount sufficient that, in thermogravimetric
measurements of the lubricating oil by a Thermogravimetric Engine
Oil Simulation Test, carbon black decomposition temperature is
increased as compared to the carbon black decomposition temperature
in a lubricating oil containing calcium or magnesium. A lubricating
oil useful for preventing or reducing low speed pre-ignition in an
engine lubricated with the lubricating oil. The lubricating oils of
this disclosure are particularly advantageous as passenger vehicle
engine oil (PVEO) products.
Inventors: |
Smith; Jordan C.; (Marlton,
NJ) ; Burns, III; Raymond G.; (Easton, PA) ;
Dance; Smruti A.; (Robbinsville, NJ) ; Deckman;
Douglas E.; (Easton, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
64427214 |
Appl. No.: |
16/176161 |
Filed: |
October 31, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62594233 |
Dec 4, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 107/02 20130101;
C10N 2030/45 20200501; C10M 125/10 20130101; C10M 2201/041
20130101; C10N 2010/08 20130101; C10N 2030/52 20200501; C10M
2203/102 20130101; C10N 2030/00 20130101; C10N 2010/14 20130101;
C10N 2030/08 20130101; C10N 2040/25 20130101; C10N 2040/255
20200501; C10M 2205/028 20130101; C10N 2030/10 20130101; C10M
169/04 20130101; C10M 2201/062 20130101; C10M 125/02 20130101; C10N
2010/02 20130101; C10N 2010/06 20130101; C10M 2205/0206
20130101 |
International
Class: |
C10M 169/04 20060101
C10M169/04; C10M 107/02 20060101 C10M107/02; C10M 125/02 20060101
C10M125/02; C10M 125/10 20060101 C10M125/10 |
Claims
1. A method for preventing or reducing low speed pre-ignition in an
engine lubricated with a lubricating oil by using as the
lubricating oil a formulated oil, said formulated oil having a
composition comprising a lubricating oil base stock as a major
component; and at least one lubricating oil additive, as a minor
component; wherein said lubricating oil contains at least one metal
or metalloid in an amount sufficient that, in thermogravimetric
measurements of the lubricating oil by a Thermogravimetric Engine
Oil Simulation Test, carbon black decomposition temperature is
increased as compared to the carbon black decomposition temperature
in a lubricating oil containing calcium or magnesium.
2. The method of claim 1 wherein, in thermogravimetric measurements
of the lubricating oil by a Thermogravimetric Engine Oil Simulation
Test, the carbon black decomposition temperature is increased by at
least 10.degree. C. as compared to the carbon black decomposition
temperature in a lubricating oil containing calcium or
magnesium.
3. The method of claim 1 wherein, in thermogravimetric measurements
of the lubricating oil by a Thermogravimetric Engine Oil Simulation
Test, the carbon black decomposition temperature is increased by at
least 25.degree. C. as compared to the carbon black decomposition
temperature in a lubricating oil containing calcium or
magnesium.
4. The method of claim 1 wherein the engine exhibits greater than
about 10% reduced low speed pre-ignition, based on normalized low
speed pre-ignition (LSPI) counts per 25,000 engine cycles, engine
operation at 2000 revolutions per minute (RPM) and brake mean
effective pressure (BMEP) at 18 bar, as compared to low speed
pre-ignition performance achieved in an engine using a lubricating
oil containing calcium or magnesium.
5. The method of claim 1 wherein the at least one metal or
metalloid comprises sodium, manganese, titanium, aluminum, or
mixtures thereof.
6. The method of claim 1 wherein the at least one metal or
metalloid is present in the lubricating oil in an amount from about
100 ppm to about 25,000 ppm.
7. The method of claim 1 wherein (i) the at least one metal or
metalloid is present in the lubricating oil in an amount from about
100 ppm to about 1000 ppm; (ii) total base number (TBN), as
measured by ASTM D2896, of the lubricating oil ranges from about 2
mg KOH to about 17 mg KOH; (iii) total sulfated ash of the
lubricating oil ranges from about 0.01 to about 1 wt %.
8. The method of claim 1 wherein the at least one metal or
metalloid is incorporated into the lubricating oil by maintaining
constant ash, maintaining constant detergent metal, maintaining
constant total base number (TBN), or top treating.
9. The method of claim 1 wherein the at least one metal or
metalloid is incorporated into the lubricating oil through the at
least one lubricating oil additive.
10. The method of claim 1 wherein the at least one lubricating oil
additive is selected from the group consisting of a salicylate, a
carboxylate, a sulfonate, a phenate, a stearate, and an oxide.
11. The method of claim 1 wherein the at least one lubricating oil
additive has a total sulfated ash from about 0.02 to about 0.17 wt
%.
12. The method of claim 1 wherein the at least one lubricating oil
additive comprises one or more of a detergent, dispersant,
viscosity index improver, antioxidant, pour point depressant,
corrosion inhibitor, metal deactivator, seal compatibility
additive, anti-foam agent, inhibitor, anti-rust additive, and
friction modifier.
13. The method of claim 1 wherein the lubricating oil base stock
comprises a Group II, Group III, or Group IV base oil.
14. The method of claim 1 wherein at least one lubricating oil
additive concentration ranges from about 0.1 to about 20 weight
percent, based on the total weight of the lubricating oil.
15. The method of claim 1 wherein the lubricating oil base stock
concentration ranges from about 50 to about 99 weight percent,
based on the total weight of the lubricating oil.
16. The method of claim 1 wherein the lubricating oil is a
passenger vehicle engine oil (PVEO).
17. A lubricating engine oil having a composition comprising a
lubricating oil base stock as a major component; and at least one
lubricating oil additive, as a minor component; wherein said
lubricating engine oil contains at least one metal or metalloid in
an amount sufficient that, in thermogravimetric measurements of the
lubricating engine oil by a Thermogravimetric Engine Oil Simulation
Test, carbon black decomposition temperature is increased as
compared to the carbon black decomposition temperature in a
lubricating engine oil containing calcium or magnesium.
18. The lubricating engine oil of claim 17 wherein, in
thermogravimetric measurements of the lubricating engine oil by a
Thermogravimetric Engine Oil Simulation Test, the carbon black
decomposition temperature is increased by at least 10.degree. C. as
compared to the carbon black decomposition temperature in a
lubricating engine oil containing calcium or magnesium.
19. The lubricating engine oil of claim 17 wherein, in
thermogravimetric measurements of the lubricating engine oil by a
Thermogravimetric Engine Oil Simulation Test, the carbon black
decomposition temperature is increased by at least 25.degree. C. as
compared to the carbon black decomposition temperature in a
lubricating engine oil containing calcium or magnesium.
20. The lubricating engine oil of claim 17 wherein the engine
exhibits greater than about 10% reduced low speed pre-ignition,
based on normalized low speed pre-ignition (LSPI) counts per 25,000
engine cycles, engine operation at 2000 revolutions per minute
(RPM) and brake mean effective pressure (BMEP) at 18 bar, as
compared to low speed pre-ignition performance achieved in an
engine using a lubricating engine oil containing calcium or
magnesium.
21. The lubricating engine oil of claim 17 wherein the at least one
metal or metalloid comprises sodium, manganese, titanium, aluminum,
or mixtures thereof.
22. The lubricating engine oil of claim 17 wherein the at least one
metal or metalloid is present in the lubricating engine oil in an
amount from about 100 ppm to about 25,000 ppm.
23. The lubricating engine oil of claim 17 wherein (i) the at least
one metal or metalloid is present in the lubricating engine oil in
an amount from about 100 ppm to about 1000 ppm; (ii) total base
number (TBN), as measured by ASTM D2896, of the lubricating engine
oil ranges from about 2 mg KOH to about 17 mg KOH; (iii) total
sulfated ash of the lubricating engine oil ranges from about 0.01
to about 1 wt %.
24. The lubricating engine oil of claim 17 wherein the at least one
metal or metalloid is incorporated into the lubricating engine oil
by maintaining constant ash, maintaining constant detergent metal,
maintaining constant total base number (TBN), or top treating.
25. The lubricating engine oil of claim 17 wherein the at least one
metal or metalloid is incorporated into the lubricating oil through
the at least one lubricating oil additive.
26. The lubricating engine oil of claim 17 wherein the at least one
lubricating oil additive is selected from the group consisting of a
salicylate, a carboxylate, a sulfonate, a phenate, a stearate, and
an oxide.
27. The lubricating engine oil of claim 17 wherein the at least one
lubricating oil additive has a total sulfated ash from about 0.02
to about 0.17 wt %.
28. The lubricating engine oil of claim 17 wherein the at least one
lubricating oil additive comprises one or more of a detergent,
dispersant, viscosity index improver, antioxidant, pour point
depressant, corrosion inhibitor, metal deactivator, seal
compatibility additive, anti-foam agent, inhibitor, anti-rust
additive, and friction modifier.
29. The lubricating engine oil of claim 17 wherein the lubricating
oil base stock comprises a Group II, Group III, or Group IV base
oil.
30. The lubricating engine oil of claim 17 wherein at least one
lubricating oil additive concentration ranges from about 0.1 to
about 20 weight percent, based on the total weight of the
lubricating engine oil.
31. The lubricating engine oil of claim 17 wherein the lubricating
oil base stock concentration ranges from about 50 to about 99
weight percent, based on the total weight of the lubricating engine
oil.
32. The lubricating engine oil of claim 17 which is a passenger
vehicle engine oil (PVEO).
33. An engine lubricated with the lubricating engine oil of claim
17.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/594,233, filed on Dec. 4, 2017, the entire
contents of which are incorporated herein by reference.
FIELD
[0002] This disclosure relates to a method for preventing or
reducing low speed pre-ignition (LSPI) in an engine lubricated with
a lubricating oil by using as the lubricating oil a formulated oil
that has at least one metal or metalloid present in a particular
amount in the formulated oil. The lubricating oils of this
disclosure are useful as passenger vehicle engine oil (PVEO)
products.
BACKGROUND
[0003] Pre-ignition in a flame propagation (or "spark-ignition")
engine describes an event wherein the air/fuel mixture in the
cylinder ignites before the spark plug fires. Pre-ignition is
initiated by an ignition source other than the spark, such as hot
spots in the combustion chamber, a spark plug that runs too hot for
the application, or carbonaceous deposits in the combustion chamber
heated to incandescence by previous engine combustion events.
[0004] Many passenger car manufacturers have observed intermittent
pre-ignition in their production turbocharged gasoline engines,
particularly at low speeds and medium-to-high loads. At these
elevated loads, pre-ignition usually results in severe engine knock
that can damage the engine. The cause of the pre-ignition is not
fully understood, and may in fact be attributed to multiple
phenomena such as hot deposits within the combustion chamber,
elevated levels of lubricant vapor entering from the PCV system,
oil seepage past the turbocharger compressor seals or oil and/or
fuel droplet auto-ignition during the compression stroke.
[0005] Pre-ignition can sharply increase combustion chamber
temperatures and lead to rough engine operation or loss of
performance. Traditional methods of eliminating pre-ignition
include, for example, proper spark plug selection, proper fuel/air
mixture adjustment, and periodic cleaning of the combustion
chambers. Hardware solutions such as cooled exhaust gas
recirculation (EGR) are known, but these can be costly to implement
and present packaging problems.
[0006] Low speed pre-ignition (LSPI) is a type of abnormal
combustion affecting engines operating at high brake mean effective
pressure (BMEP) and low engine speed (RPM). This includes internal
combustion engines using a variety of fuels, including natural gas,
gasoline, diesel, biofuels, and the like. Downsized, downspeeded,
turbocharged engines are most susceptible to operating under these
engine conditions and are thus more susceptible to LSPI. As the
automobile industry continues to move towards further downsizing,
downspeeding, and increased turbocharging to increase vehicle fuel
economy and reduce carbon dioxide emissions, the concern over LSPI
continues to grow.
[0007] The further development of downspeeded, turbocharged
gasoline engines is being impeded by LSPI. A solution to this
problem or even a mitigation of its occurrence would remove
barriers for original equipment manufacturer (OEM) technology and
efficiency improvement. A lubricant formulation solution would
enable product differentiation with regard to LSPI.
[0008] Although pre-ignition problems can be and are being resolved
by optimization of internal engine components and by the use of new
component technology such as electronic controls, modification of
the lubricating oil compositions used to lubricate such engines is
desirable. For example, it would be desirable to develop new
lubricating oil formulations which are particularly useful in
internal combustion engines and, when used in internal combustion
engines, will prevent or minimize the pre-ignition problems. It is
desired that the lubricating oil composition be useful in
lubricating gasoline-fueled, spark-ignited engines.
[0009] Despite the advances in lubricant oil formulation
technology, there exists a need for an engine oil lubricant that
effectively prevents or reduces low speed pre-ignition especially
for downsized, downspeeded, turbocharged engines.
SUMMARY
[0010] This disclosure relates in part to new lubricating oil
formulations which are particularly useful in internal combustion
engines and, when used in internal combustion engines will prevent
or minimize pre-ignition problems. The lubricating oil compositions
of this disclosure are useful in lubricating gasoline-fueled,
spark-ignited engines. The lubricant formulation chemistry of this
disclosure can be used to prevent or control the detrimental effect
of LSPI in engines which have already been designed or sold in the
marketplace as well as future engine technology. The lubricant
formulation chemistry of this disclosure removes barriers for OEM
technology and efficiency improvement, and enables further
development of downspeeded, turbocharged gasoline engines that is
currently being impeded by LSPI. The lubricant formulation solution
afforded by this disclosure for preventing or reducing LSPI enables
product differentiation with regard to LSPI.
[0011] In addition to LSPI prevention, the lubricating oil
formulations of this disclosure can also achieve desired
performance characteristics in terms of wear, cleanliness, fuel
economy, and the like. In accordance with this disclosure,
formulators have increased flexibility to maximize other
performance attributes, while minimizing LSPI activity.
[0012] This disclosure also relates in part to a method for
preventing or reducing low speed pre-ignition in an engine
lubricated with a lubricating oil by using as the lubricating oil a
formulated oil. The formulated oil has a composition comprising a
lubricating oil base stock as a major component, and at least one
lubricating oil additive, as a minor component. The lubricating oil
contains at least one metal or metalloid in an amount sufficient
that, in thermogravimetric measurements of the lubricating oil by a
Thermogravimetric Engine Oil Simulation Test, carbon black
decomposition temperature is increased as compared to the carbon
black decomposition temperature in a lubricating oil containing
calcium or magnesium.
[0013] This disclosure further relates in part to a lubricating
engine oil having a composition comprising a lubricating oil base
stock as a major component, and at least one lubricating oil
additive, as a minor component. The lubricating engine oil contains
at least one metal or metalloid in an amount sufficient that, in
thermogravimetric measurements of the lubricating engine oil by a
Thermogravimetric Engine Oil Simulation Test, carbon black
decomposition temperature is increased as compared to the carbon
black decomposition temperature in a lubricating engine oil
containing calcium or magnesium.
[0014] It has been surprisingly found that, in accordance with this
disclosure, prevention or reduction of LSPI can be attained in an
engine lubricated with a lubricating oil by using as the
lubricating oil a formulated oil having at least one metal or
metalloid in an amount sufficient that, in thermogravimetric
measurements of the lubricating oil by a Thermogravimetric Engine
Oil Simulation Test, the carbon black decomposition temperature is
increased by at least 10.degree. C., or by at least 25.degree. C.,
as compared to the carbon black decomposition temperature in a
lubricating oil containing calcium or magnesium. The carbon black
decomposition temperature is an indicator of the catalytic activity
of the metal oxide for promoting auto-ignition. An increase in the
decomposition temperature of a lubricant corresponds to an increase
of the auto-ignition temperature of the LSPI precursors resulting
in less LSPI activity.
[0015] In addition, it has been surprisingly found that, in
accordance with this disclosure, lubricant compositions containing
at least one of sodium, manganese, titanium, aluminum, or mixtures
thereof, in combination with other typical lubricating oil
additives, and in amounts from about 100 ppm to about 25,000 ppm,
provide improved LSPI performance.
[0016] Other objects and advantages of the present disclosure will
become apparent from the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows carbon decomposition temperatures of various
metal oxides in a carbon black/PAO mixture, in accordance with the
Examples.
[0018] FIG. 2 shows carbon decomposition temperatures of various
metal oxides in a carbon black/base stock mixture in which barium
and titanium and various base stocks were used, in accordance with
the Examples.
[0019] FIG. 3 shows carbon decomposition temperatures of various
metal oxides in a carbon black mixture in which barium and titanium
and PAO base stock were used with varying concentrations of metal
oxide, in accordance with the Examples.
DETAILED DESCRIPTION
[0020] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art. The phrase "major amount" or "major component" as it
relates to components included within the lubricating oils of the
specification and the claims means greater than or equal to 50 wt.
%, or greater than or equal to 60 wt. %, or greater than or equal
to 70 wt. %, or greater than or equal to 80 wt. %, or greater than
or equal to 90 wt. % based on the total weight of the lubricating
oil. The phrase "minor amount" or "minor component" as it relates
to components included within the lubricating oils of the
specification and the claims means less than 50 wt. %, or less than
or equal to 40 wt. %, or less than or equal to 30 wt. %, or greater
than or equal to 20 wt. %, or less than or equal to 10 wt. %, or
less than or equal to 5 wt. %, or less than or equal to 2 wt. %, or
less than or equal to 1 wt. %, based on the total weight of the
lubricating oil. The phrase "essentially free" as it relates to
components included within the lubricating oils of the
specification and the claims means that the particular component is
at 0 weight % within the lubricating oil, or alternatively is at
impurity type levels within the lubricating oil (less than 100 ppm,
or less than 20 ppm, or less than 10 ppm, or less than 1 ppm). The
phrase "other lubricating oil additives" as used in the
specification and the claims means other lubricating oil additives
that are not specifically recited in the particular section of the
specification or the claims. For example, other lubricating oil
additives may include, but are not limited to, antioxidants,
detergents, dispersants, antiwear additives, corrosion inhibitors,
viscosity modifiers, metal passivators, pour point depressants,
seal compatibility agents, antifoam agents, extreme pressure
agents, friction modifiers and combinations thereof.
[0021] It has now been found that prevention or reduction of LSPI
can be attained in an engine lubricated with a lubricating oil by
using as the lubricating oil a formulated oil that includes at
least one metal or metalloid in an amount sufficient that, in
thermogravimetric measurements of the lubricating oil by a
Thermogravimetric Engine Oil Simulation Test as described herein,
carbon black decomposition temperature is increased as compared to
the carbon black decomposition temperature in a lubricating oil
containing calcium or magnesium.
[0022] In an embodiment, in thermogravimetric measurements of the
lubricating oil by a Thermogravimetric Engine Oil Simulation Test,
the carbon black decomposition temperature is increased by at least
10.degree. C. as compared to the carbon black decomposition
temperature in a lubricating oil containing calcium or
magnesium.
[0023] In another embodiment, in thermogravimetric measurements of
the lubricating oil by a Thermogravimetric Engine Oil Simulation
Test, the carbon black decomposition temperature is increased by at
least 25.degree. C. as compared to the carbon black decomposition
temperature in a lubricating oil containing calcium or
magnesium.
[0024] Illustrative metals and metalloids useful in the lubricating
oils of this disclosure include, for example, sodium, manganese,
titanium, aluminum, or mixtures thereof.
[0025] The at least one metal or metalloid is present in the
lubricating oils of this disclosure in an amount from about 10 ppm
to about 25,000 ppm, preferably from about 50 ppm to about 10,000
ppm, and more preferably from about 100 ppm to about 5,000 ppm, and
more preferably from about 100 ppm to about 1,000 ppm, and more
preferably from about 100 ppm to about 500 ppm.
[0026] In an embodiment, the total base number (TBN), as measured
by ASTM D2896, of the lubricating oil ranges from about 2 mg KOH to
about 17 mg KOH, preferably from about 3 mg KOH to about 16 mg KOH,
and more preferably from about 4 mg KOH to about 16 mg KOH.
[0027] In a further embodiment, the total sulfated ash of the
lubricating oil ranges from about 0.01 to about 1 wt %, preferably
from about 0.01 to about 0.8 wt %, more preferably from about 0.01
to about 0.6 wt %, more preferably from about 0.01 to about 0.4 wt
%, more preferably from about 0.01 to about 0.17 wt %, more
preferably from about 0.05 to about 0.16 wt %, and more preferably
from about 0.1 to about 0.15 wt %.
[0028] The at least one metal or metalloid can be incorporated into
the lubricating oil by several methods, for example, by maintaining
constant ash, maintaining constant detergent metal, maintaining
constant total base number (TBN), top treating, and the like.
[0029] Preferably, the at least one metal or metalloid can be
incorporated into the lubricating oil through at least one
lubricating oil additive (e.g., metal-containing detergent). The at
least one lubricating oil additive is preferably selected from a
salicylate, a carboxylate, a sulfonate, a phenate, a stearate, an
oxide, and the like.
[0030] The at least one lubricating oil additive can have a total
sulfated ash content from about 0.02 to about 0.17 wt %, preferably
from about 0.05 to about 0.16 wt %, and more preferably from about
0.1 to about 0.15 wt %.
[0031] In addition, it has been found that reduction of LSPI can be
attained in an engine lubricated with a lubricating oil by using as
the lubricating oil a formulated oil that has a particular base
stock (e.g., Group IV base stock) and at least one metal or
metalloid in an amount from about 100 ppm to about 25,000 ppm. The
lubricating oils of this disclosure are particularly advantageous
in internal combustion engines using a variety of fuels including
natural gas, gasoline, diesel, biofuels and the like, and for a
variety of applications including passenger vehicle engine oils and
natural gas engine oils.
[0032] The lubricating oils of this disclosure are particularly
useful in internal combustion engines and, when used in internal
combustion engines, will prevent or minimize pre-ignition problems.
The lubricating oil compositions of this disclosure are useful in
lubricating gasoline-fueled, spark-ignited engines.
[0033] As described herein, the lubricant formulation chemistry of
this disclosure can be used to prevent or control the detrimental
effect of LSPI in engines which have already been designed or sold
in the marketplace as well as future engine technology. The
lubricant formulation chemistry of this disclosure removes barriers
for OEM technology and efficiency improvement, and enables further
development of downspeeded, turbocharged gasoline engines that is
currently being impeded by LSPI. The lubricant formulation solution
afforded by this disclosure for preventing or reducing LSPI enables
product differentiation with regard to LSPI.
[0034] Lubricating Oil Base Stocks
[0035] A wide range of lubricating base oils is known in the art.
Lubricating base oils that are useful in the present disclosure are
both natural oils, and synthetic oils, and unconventional oils (or
mixtures thereof) can be used unrefined, refined, or rerefined (the
latter is also known as reclaimed or reprocessed oil). Unrefined
oils are those obtained directly from a natural or synthetic source
and used without added purification. These include shale oil
obtained directly from retorting operations, petroleum oil obtained
directly from primary distillation, and ester oil obtained directly
from an esterification process. Refined oils are similar to the
oils discussed for unrefined oils except refined oils are subjected
to one or more purification steps to improve at least one
lubricating oil property. One skilled in the art is familiar with
many purification processes. These processes include solvent
extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation. Rerefined oils are
obtained by processes analogous to refined oils but using an oil
that has been previously used as a feed stock.
[0036] Groups I, II, III, IV, and V are broad base oil stock
categories developed and defined by the American Petroleum
Institute (API Publication 1509; www.API.org) to create guidelines
for lubricant base oils. Group I base stocks have a viscosity index
of between 80 to 120 and contain greater than 0.03% sulfur and/or
less than 90% saturates. Group II base stocks have a viscosity
index of between about 80 to 120, and contain less than or equal to
0.03% sulfur and greater than or equal to 90% saturates. Group III
stocks have a viscosity index greater than or equal to 120 and
contain less than or equal to 0.03% sulfur and greater than or
equal to 90% saturates. Group IV includes polyalphaolefins (PAO).
Group V base stock includes base stocks not included in Groups
I-IV. The table below summarizes properties of each of these five
groups.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity Index
Group I <90 and/or >0.03% and .gtoreq.80 and <120 Group II
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and <120 Group III
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.120 Group IV Includes
polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III, or IV
[0037] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source, for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful. Natural oils vary also
as to the method used for their production and purification, for
example, their distillation range and whether they are straight run
or cracked, hydrorefined, or solvent extracted.
[0038] Group II and/or Group III hydroprocessed or hydrocracked
base stocks, including synthetic oils such as polyalphaolefins,
alkyl aromatics and synthetic esters are also well known base stock
oils.
[0039] Synthetic oils include hydrocarbon oil. Hydrocarbon oils
include oils such as polymerized and interpolymerized olefins
(polybutylenes, polypropylenes, propylene isobutylene copolymers,
ethylene-olefin copolymers, and ethylene-alphaolefin copolymers,
for example). Polyalphaolefin (PAO) oil base stocks are commonly
used synthetic hydrocarbon oil. By way of example, PAOs derived
from C.sub.6, C.sub.8, C.sub.10, C.sub.12, C.sub.14 olefins or
mixtures thereof may be utilized. See U.S. Pat. Nos. 4,956,122;
4,827,064; and 4,827,073.
[0040] The number average molecular weights of the PAOs, which are
known materials and generally available on a major commercial scale
from suppliers such as ExxonMobil Chemical Company, Chevron
Phillips Chemical Company, BP, and others, typically vary from
about 250 to about 3,000, although PAO's may be made in viscosities
up to about 150 cSt (100.degree. C.). The PAOs are typically
comprised of relatively low molecular weight hydrogenated polymers
or oligomers of alphaolefins which include, but are not limited to,
C.sub.2 to about C.sub.32 alphaolefins with the C.sub.6 to about
C.sub.16 alphaolefins, such as 1-hexene, 1-octene, 1-decene,
1-dodecene, 1-tetradocene, and the like, being preferred. The
preferred polyalphaolefins are poly-1-hexene, poly-1-octene,
poly-1-decene and poly-1-dodecene and mixtures thereof and mixed
olefin-derived polyolefins. However, the dimers of higher olefins
in the range of C.sub.14 to C.sub.18 may be used to provide low
viscosity base stocks of acceptably low volatility. Depending on
the viscosity grade and the starting oligomer, the PAOs may be
predominantly trimers and tetramers of the starting olefins, with
minor amounts of the higher oligomers, having a viscosity range of
1.5 to 12 cSt. PAO fluids of particular use may include 3.0 cSt,
3.4 cSt, and/or 3.6 cSt and combinations thereof. Bi-modal mixtures
of PAO fluids having a viscosity range of 1.5 to 150 cSt may be
used if desired.
[0041] The PAO fluids may be conveniently made by the
polymerization of an alphaolefin in the presence of a
polymerization catalyst such as the Friedel-Crafts catalysts
including, for example, aluminum trichloride, boron trifluoride or
complexes of boron trifluoride with water, alcohols such as
ethanol, propanol or butanol, carboxylic acids or esters such as
ethyl acetate or ethyl propionate. For example the methods
disclosed by U.S. Pat. No. 4,149,178 or 3,382,291 may be
conveniently used herein. Other descriptions of PAO synthesis are
found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C.sub.14 to C.sub.18
olefins are described in U.S. Pat. No. 4,218,330.
[0042] Other useful lubricant oil base stocks include wax isomerate
base stocks and base oils, comprising hydroisomerized waxy stocks
(e.g. waxy stocks such as gas oils, slack waxes, fuels hydrocracker
bottoms, etc.), hydroisomerized Fischer-Tropsch waxes,
Gas-to-Liquids (GTL) base stocks and base oils, and other wax
isomerate hydroisomerized base stocks and base oils, or mixtures
thereof Fischer-Tropsch waxes, the high boiling point residues of
Fischer-Tropsch synthesis, are highly paraffinic hydrocarbons with
very low sulfur content. The hydroprocessing used for the
production of such base stocks may use an amorphous
hydrocracking/hydroisomerization catalyst, such as one of the
specialized lube hydrocracking (LHDC) catalysts or a crystalline
hydrocracking/hydroisomerization catalyst, preferably a zeolitic
catalyst. For example, one useful catalyst is ZSM-48 as described
in U.S. Pat. No. 5,075,269, the disclosure of which is incorporated
herein by reference in its entirety. Processes for making
hydrocracked/hydroisomerized distillates and
hydrocracked/hydroisomerized waxes are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as
well as in British Patent Nos. 1,429,494; 1,350,257; 1,440,230 and
1,390,359. Each of the aforementioned patents is incorporated
herein in their entirety. Particularly favorable processes are
described in European Patent Application Nos. 464546 and 464547,
also incorporated herein by reference. Processes using
Fischer-Tropsch wax feeds are described in U.S. Pat. Nos. 4,594,172
and 4,943,672, the disclosures of which are incorporated herein by
reference in their entirety.
[0043] Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived
base oils, and other wax-derived hydroisomerized (wax isomerate)
base oils be advantageously used in the instant disclosure, and may
have useful kinematic viscosities at 100.degree. C. of about 3 cSt
to about 50 cSt, preferably about 3 cSt to about 30 cSt, more
preferably about 3.5 cSt to about 25 cSt, as exemplified by GTL 4
with kinematic viscosity of about 4.0 cSt at 100.degree. C. and a
viscosity index of about 141. These Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and other wax-derived
hydroisomerized base oils may have useful pour points of about
-20.degree. C. or lower, and under some conditions may have
advantageous pour points of about -25.degree. C. or lower, with
useful pour points of about -30.degree. C. to about -40.degree. C.
or lower. Useful compositions of Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and wax-derived
hydroisomerized base oils are recited in U.S. Pat. Nos. 6,080,301;
6,090,989, and 6,165,949 for example, and are incorporated herein
in their entirety by reference.
[0044] The hydrocarbyl aromatics can be used as base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least about 5% of its weight derived from an aromatic moiety such
as a benzenoid moiety or naphthenoid moiety, or their derivatives.
These hydrocarbyl aromatics include alkyl benzenes, alkyl
naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyl
diphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol,
and the like. The aromatic can be mono-alkylated, dialkylated,
polyalkylated, and the like. The aromatic can be mono- or
poly-functionalized. The hydrocarbyl groups can also be comprised
of mixtures of alkyl groups, alkenyl groups, alkynyl, cycloalkyl
groups, cycloalkenyl groups and other related hydrocarbyl groups.
The hydrocarbyl groups can range from about C.sub.6 up to about
C.sub.60 with a range of about C.sub.8 to about C.sub.20 often
being preferred. A mixture of hydrocarbyl groups is often
preferred, and up to about three such substituents may be present.
The hydrocarbyl group can optionally contain sulfur, oxygen, and/or
nitrogen containing substituents. The aromatic group can also be
derived from natural (petroleum) sources, provided at least about
5% of the molecule is comprised of an above-type aromatic moiety.
Viscosities at 100.degree. C. of approximately 3 cSt to about 50
cSt are preferred, with viscosities of approximately 3.4 cSt to
about 20 cSt often being more preferred for the hydrocarbyl
aromatic component. In one embodiment, an alkyl naphthalene where
the alkyl group is primarily comprised of 1-hexadecene is used.
Other alkylates of aromatics can be advantageously used.
Naphthalene or methyl naphthalene, for example, can be alkylated
with olefins such as octene, decene, dodecene, tetradecene or
higher, mixtures of similar olefins, and the like. Useful
concentrations of hydrocarbyl aromatic in a lubricant oil
composition can be about 2% to about 25%, preferably about 4% to
about 20%, and more preferably about 4% to about 15%, depending on
the application.
[0045] Alkylated aromatics such as the hydrocarbyl aromatics of the
present disclosure may be produced by well-known Friedel-Crafts
alkylation of aromatic compounds. See Friedel-Crafts and Related
Reactions, Olah, G. A. (ed.), Inter-science Publishers, New York,
1963. For example, an aromatic compound, such as benzene or
naphthalene, is alkylated by an olefin, alkyl halide or alcohol in
the presence of a Friedel-Crafts catalyst. See Friedel-Crafts and
Related Reactions, Vol. 2, part 1, chapters 14, 17, and 18, See
Olah, G. A. (ed.), Inter-science Publishers, New York, 1964. Many
homogeneous or heterogeneous, solid catalysts are known to one
skilled in the art. The choice of catalyst depends on the
reactivity of the starting materials and product quality
requirements. For example, strong acids such as AlCl.sub.3,
BF.sub.3, or HF may be used. In some cases, milder catalysts such
as FeCl.sub.3 or SnCl.sub.4 are preferred. Newer alkylation
technology uses zeolites or solid super acids.
[0046] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of mono-carboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl) sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl
sebacate, etc.
[0047] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols, preferably
the hindered polyols (such as the neopentyl polyols, e.g.,
neopentyl glycol, trimethylol ethane,
2-methyl-2-propyl-1,3-propanediol, trimethylol propane,
pentaerythritol and dipentaerythritol) with alkanoic acids
containing at least about 4 carbon atoms, preferably C.sub.5 to
C.sub.30 acids such as saturated straight chain fatty acids
including caprylic acid, capric acid, lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid, or mixtures of any of these materials.
[0048] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipentaerythritol with one or more
monocarboxylic acids containing from about 5 to about 10 or more
carbon atoms. These esters are widely available commercially, for
example, the Mobil P-41 and P-51 esters of ExxonMobil Chemical
Company.
[0049] Preferred synthetic esters useful in this disclosure have a
kinematic viscosity at 100.degree. C. of about 3 cSt to about 50
cSt, preferably about 3 cSt to about 30 cSt, more preferably about
3.5 cSt to about 25 cSt, and even more preferably about 2 cSt to
about 8 cSt. Group V base oils useful in this disclosure preferably
comprise an ester at a concentration of about 2% to about 20%,
preferably from about 5% to about 15%.
[0050] Also useful are esters derived from renewable material such
as coconut, palm, rapeseed, soy, sunflower and the like. These
esters may be monoesters, di-esters, polyol esters, complex esters,
or mixtures thereof. These esters are widely available
commercially, for example, the Mobil P-51 ester of ExxonMobil
Chemical Company.
[0051] Engine oil formulations containing renewable esters are
included in this disclosure. For such formulations, the renewable
content of the ester is typically greater than about 70 weight
percent, preferably more than about 80 weight percent and most
preferably more than about 90 weight percent.
[0052] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0053] Non-conventional or unconventional base stocks/base oils
include one or more of a mixture of base stock(s) derived from one
or more Gas-to-Liquids (GTL) materials, as well as
isomerate/isodewaxate base stock(s) derived from natural wax or
waxy feeds, mineral and or non-mineral oil waxy feed stocks such as
slack waxes, natural waxes, and waxy stocks such as gas oils, waxy
fuels hydrocracker bottoms, waxy raffinate, hydrocrackate, thermal
crackates, or other mineral, mineral oil, or even non-petroleum oil
derived waxy materials such as waxy materials received from coal
liquefaction or shale oil, and mixtures of such base stocks.
[0054] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds and/or elements as feed
stocks such as hydrogen, carbon dioxide, carbon monoxide, water,
methane, ethane, ethylene, acetylene, propane, propylene, propyne,
butane, butylenes, and butynes. GTL base stocks and/or base oils
are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons; for example, waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feed stocks. GTL base stock(s) and/or base oil(s)
include oils boiling in the lube oil boiling range (1)
separated/fractionated from synthesized GTL materials such as, for
example, by distillation and subsequently subjected to a final wax
processing step which involves either or both of a catalytic
dewaxing process, or a solvent dewaxing process, to produce lube
oils of reduced/low pour point; (2) synthesized wax isomerates,
comprising, for example, hydrodewaxed or hydroisomerized cat and/or
solvent dewaxed synthesized wax or waxy hydrocarbons; (3)
hydrodewaxed or hydroisomerized cat and/or solvent dewaxed
Fischer-Tropsch (F-T) material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates); preferably
hydrodewaxed or hydroisomerized/followed by cat and/or solvent
dewaxing dewaxed F-T waxy hydrocarbons, or hydrodewaxed or
hydroisomerized/followed by cat (or solvent) dewaxing dewaxed, F-T
waxes, or mixtures thereof.
[0055] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed or hydroisomerized/followed by
cat and/or solvent dewaxed wax or waxy feed, preferably F-T
material derived base stock(s) and/or base oil(s), are
characterized typically as having kinematic viscosities at
100.degree. C. of from about 2 mm.sup.2/s to about 50 mm.sup.2/s
(ASTM D445). They are further characterized typically as having
pour points of -5.degree. C. to about -40.degree. C. or lower (ASTM
D97). They are also characterized typically as having viscosity
indices of about 80 to about 140 or greater (ASTM D2270).
[0056] The term GTL base stock and/or base oil and/or wax isomerate
base stock and/or base oil is to be understood as embracing
individual fractions of such materials of wide viscosity range as
recovered in the production process, mixtures of two or more of
such fractions, as well as mixtures of one or two or more low
viscosity fractions with one, two or more higher viscosity
fractions to produce a blend wherein the blend exhibits a target
kinematic viscosity.
[0057] The GTL material, from which the GTL base stock(s) and/or
base oil(s) is/are derived is preferably an F-T material (i.e.,
hydrocarbons, waxy hydrocarbons, wax).
[0058] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) and hydrodewaxed, or
hydroisomerized/cat (and/or solvent) dewaxed base stock(s) and/or
base oil(s) typically have very low sulfur and nitrogen content,
generally containing less than about 10 ppm, and more typically
less than about 5 ppm of each of these elements. The sulfur and
nitrogen content of GTL base stock(s) and/or base oil(s) obtained
from F-T material, especially F-T wax, is essentially nil. In
addition, the absence of phosphorous and aromatics make this
material especially suitable for the formulation of low sulfur,
sulfated ash, and phosphorus (low SAP) products.
[0059] Base oils for use in the formulated lubricating oils useful
in the present disclosure are any of the variety of oils
corresponding to API Group I, Group II, Group III, Group IV, and
Group V oils and mixtures thereof, preferably API Group II, Group
III, Group IV, and Group V oils and mixtures thereof, more
preferably the Group III to Group V base oils due to their
exceptional volatility, stability, viscometric and cleanliness
features.
[0060] The base oil constitutes the major component of the engine
oil lubricant composition of the present disclosure and typically
is present in an amount ranging from about 50 to about 99 weight
percent, preferably from about 70 to about 95 weight percent, and
more preferably from about 85 to about 95 weight percent, based on
the total weight of the composition. The base oil may be selected
from any of the synthetic or natural oils typically used as
crankcase lubricating oils for spark-ignited and
compression-ignited engines. The base oil conveniently has a
kinematic viscosity, according to ASTM standards, of about 2.5 cSt
to about 12 cSt (or mm.sup.2/s) at 100.degree. C. and preferably of
about 2.5 cSt to about 9 cSt (or mm.sup.2/s) at 100.degree. C.
Mixtures of synthetic and natural base oils may be used if desired.
Mixtures of Group III, IV, and V may be preferably used if
desired.
Lubricating Oil Additives
[0061] The formulated lubricating oil useful in the present
disclosure may additionally contain one or more of the other
commonly used lubricating oil performance additives including but
not limited to antiwear agents, dispersants, detergents, corrosion
inhibitors, rust inhibitors, metal deactivators, extreme pressure
additives, anti-seizure agents, wax modifiers, viscosity index
improvers, viscosity modifiers, fluid-loss additives, seal
compatibility agents, friction modifiers, lubricity agents,
anti-staining agents, chromophoric agents, defoamants,
demulsifiers, emulsifiers, densifiers, wetting agents, gelling
agents, tackiness agents, colorants, and others. For a review of
many commonly used additives, see Klamann in Lubricants and Related
Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN 0-89573-177-0.
Reference is also made to "Lubricant Additives" by M. W. Ranney,
published by Noyes Data Corporation of Parkridge, N.J. (1973); see
also U.S. Pat. No. 7,704,930, the disclosure of which is
incorporated herein in its entirety. These additives are commonly
delivered with varying amounts of diluent oil, that may range from
5 weight percent to 50 weight percent.
[0062] The types and quantities of performance additives used in
combination with the instant disclosure in lubricant compositions
are not limited by the examples shown herein as illustrations.
Antiwear Additives
[0063] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) can be a useful component of
the lubricating oils of this disclosure. ZDDP can be derived from
primary alcohols, secondary alcohols or mixtures thereof. ZDDP
compounds generally are of the formula
Zn[SP(S)(OR.sup.1)(OR.sup.2)].sub.2
where R.sup.1 and R.sup.2 are C.sub.1-C.sub.18 alkyl groups,
preferably C.sub.2-C.sub.12 alkyl groups. These alkyl groups may be
straight chain or branched. Alcohols used in the ZDDP can be
propanol, 2-propanol, butanol, secondary butanol, pentanols,
hexanols such as 4-methyl-2-pentanol, n-hexanol, n-octanol, 2-ethyl
hexanol, alkylated phenols, and the like. Mixtures of secondary
alcohols or of primary and secondary alcohol can be preferred.
Alkyl aryl groups may also be used.
[0064] Preferable zinc dithiophosphates which are commercially
available include secondary zinc dithiophosphates such as those
available from for example, The Lubrizol Corporation under the
trade designations "LZ 677A", "LZ 1095" and "LZ 1371", from for
example Chevron Oronite under the trade designation "OLOA 262" and
from for example Afton Chemical under the trade designation "HITEC
7169".
[0065] The ZDDP is typically used in amounts of from about 0.3
weight percent to about 1.5 weight percent, preferably from about
0.4 weight percent to about 1.2 weight percent, more preferably
from about 0.5 weight percent to about 1.0 weight percent, and even
more preferably from about 0.6 weight percent to about 0.8 weight
percent, based on the total weight of the lubricating oil, although
more or less can often be used advantageously. Preferably, the ZDDP
is a secondary ZDDP and present in an amount of from about 0.6 to
1.0 weight percent of the total weight of the lubricating oil.
Dispersants
[0066] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
used in the formulation of the lubricating oil may be ashless or
ash-forming in nature. Preferably, the dispersant is ashless. So
called ashless dispersants are organic materials that form
substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0067] Suitable dispersants typically contain a polar group
attached to a relatively high molecular weight hydrocarbon chain.
The polar group typically contains at least one element of
nitrogen, oxygen, or phosphorus. Typical hydrocarbon chains contain
50 to 400 carbon atoms.
[0068] A particularly useful class of dispersants are the
(poly)alkenylsuccinic derivatives, typically produced by the
reaction of a long chain hydrocarbyl substituted succinic compound,
usually a hydrocarbyl substituted succinic anhydride, with a
polyhydroxy or polyamino compound. The long chain hydrocarbyl group
constituting the oleophilic portion of the molecule which confers
solubility in the oil, is normally a polyisobutylene group. Many
examples of this type of dispersant are well known commercially and
in the literature. Exemplary U.S. patents describing such
dispersants are U.S. Pat. Nos. 3,172,892; 3,2145,707; 3,219,666;
3,316,177; 3,341,542; 3,444,170; 3,454,607; 3,541,012; 3,630,904;
3,632,511; 3,787,374 and 4,234,435. Other types of dispersant are
described in U.S. Pat. Nos. 3,036,003; 3,200,107; 3,254,025;
3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,413,347; 3,697,574;
3,725,277; 3,725,480; 3,726,882; 4,454,059; 3,329,658; 3,449,250;
3,519,565; 3,666,730; 3,687,849; 3,702,300; 4,100,082; 5,705,458. A
further description of dispersants may be found, for example, in
European Patent Application No. 471 071, to which reference is made
for this purpose.
[0069] Hydrocarbyl-substituted succinic acid and
hydrocarbyl-substituted succinic anhydride derivatives are useful
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful.
[0070] Succinimides are formed by the condensation reaction between
hydrocarbyl substituted succinic anhydrides and amines. Molar
ratios can vary depending on the polyamine. For example, the molar
ratio of hydrocarbyl substituted succinic anhydride to TEPA can
vary from about 1:1 to about 5:1. Representative examples are shown
in U.S. Pat. Nos. 3,087,936; 3,172,892; 3,219,666; 3,272,746;
3,322,670; and 3,652,616, 3,948,800; and Canada Patent No.
1,094,044.
[0071] Succinate esters are formed by the condensation reaction
between hydrocarbyl substituted succinic anhydrides and alcohols or
polyols. Molar ratios can vary depending on the alcohol or polyol
used. For example, the condensation product of a hydrocarbyl
substituted succinic anhydride and pentaerythritol is a useful
dispersant.
[0072] Succinate ester amides are formed by condensation reaction
between hydrocarbyl substituted succinic anhydrides and alkanol
amines. For example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0073] The molecular weight of the hydrocarbyl substituted succinic
anhydrides used in the preceding paragraphs will typically range
between 800 and 2,500 or more. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid. The above
products can also be post reacted with boron compounds such as
boric acid, borate esters or highly borated dispersants, to form
borated dispersants generally having from about 0.1 to about 5
moles of boron per mole of dispersant reaction product.
[0074] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Pat. No.
4,767,551, which is incorporated herein by reference. Process aids
and catalysts, such as oleic acid and sulfonic acids, can also be
part of the reaction mixture. Molecular weights of the alkylphenols
range from 800 to 2,500. Representative examples are shown in U.S.
Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365; 3,756,953;
3,798,165; and 3,803,039.
[0075] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this disclosure can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HNR2 group-containing reactants.
[0076] Hydrocarbyl substituted amine ashless dispersant additives
are well known to one skilled in the art; see, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197.
[0077] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
about 500 to about 5000, or from about 1000 to about 3000, or about
1000 to about 2000, or a mixture of such hydrocarbylene groups,
often with high terminal vinylic groups. Other preferred
dispersants include succinic acid-esters and amides,
alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components.
[0078] Polymethacrylate or polyacrylate derivatives are another
class of dispersants. These dispersants are typically prepared by
reacting a nitrogen containing monomer and a methacrylic or acrylic
acid esters containing 5-25 carbon atoms in the ester group.
Representative examples are shown in U.S. Pat. Nos. 2,100,993, and
6,323,164. Polymethacrylate and polyacrylate dispersants are
normally used as multifunctional viscosity modifiers. The lower
molecular weight versions can be used as lubricant dispersants or
fuel detergents.
[0079] Illustrative preferred dispersants useful in this disclosure
include those derived from polyalkenyl-substituted mono- or
dicarboxylic acid, anhydride or ester, which dispersant has a
polyalkenyl moiety with a number average molecular weight of at
least 900 and from greater than 1.3 to 1.7, preferably from greater
than 1.3 to 1.6, most preferably from greater than 1.3 to 1.5,
functional groups (mono- or dicarboxylic acid producing moieties)
per polyalkenyl moiety (a medium functionality dispersant).
Functionality (F) can be determined according to the following
formula:
F=(SAP.times.M.sub.n)/((112,200.times.A.I.)-(SAP.times.98))
wherein SAP is the saponification number (i.e., the number of
milligrams of KOH consumed in the complete neutralization of the
acid groups in one gram of the succinic-containing reaction
product, as determined according to ASTM D94); M.sub.n is the
number average molecular weight of the starting olefin polymer; and
A.I, is the percent active ingredient of the succinic-containing
reaction product (the remainder being unreacted olefin polymer,
succinic anhydride and diluent).
[0080] The polyalkenyl moiety of the dispersant may have a number
average molecular weight of at least 900, suitably at least 1500,
preferably between 1800 and 3000, such as between 2000 and 2800,
more preferably from about 2100 to 2500, and most preferably from
about 2200 to about 2400. The molecular weight of a dispersant is
generally expressed in terms of the molecular weight of the
polyalkenyl moiety. This is because the precise molecular weight
range of the dispersant depends on numerous parameters including
the type of polymer used to derive the dispersant, the number of
functional groups, and the type of nucleophilic group employed.
[0081] Polymer molecular weight, specifically M.sub.n, can be
determined by various known techniques. One convenient method is
gel permeation chromatography (GPC), which additionally provides
molecular weight distribution information (see W. W. Yau, J. J.
Kirkland and D. D. Bly, "Modern Size Exclusion Liquid
Chromatography", John Wiley and Sons, New York, 1979). Another
useful method for determining molecular weight, particularly for
lower molecular weight polymers, is vapor pressure osmometry (e.g.,
ASTM D3592).
[0082] The polyalkenyl moiety in a dispersant preferably has a
narrow molecular weight distribution (MWD), also referred to as
polydispersity, as determined by the ratio of weight average
molecular weight (M.sub.w) to number average molecular weight
(M.sub.n). Polymers having a M.sub.w/M.sub.n of less than 2.2,
preferably less than 2.0, are most desirable. Suitable polymers
have a polydispersity of from about 1.5 to 2.1, preferably from
about 1.6 to about 1.8.
[0083] Suitable polyalkenes employed in the formation of the
dispersants include homopolymers, interpolymers or lower molecular
weight hydrocarbons. One family of such polymers comprise polymers
of ethylene and/or at least one C.sub.3 to C.sub.2 alpha-olefin
having the formula H.sub.2C=CHR.sup.1 wherein R.sup.1 is a straight
or branched chain alkyl radical comprising 1 to 26 carbon atoms and
wherein the polymer contains carbon-to-carbon unsaturation, and a
high degree of terminal ethenylidene unsaturation. Preferably, such
polymers comprise interpolymers of ethylene and at least one
alpha-olefin of the above formula, wherein R.sup.1 is alkyl of from
1 to 18 carbon atoms, and more preferably is alkyl of from 1 to 8
carbon atoms, and more preferably still of from 1 to 2 carbon
atoms.
[0084] Another useful class of polymers is polymers prepared by
cationic polymerization of monomers such as isobutene and styrene.
Common polymers from this class include polyisobutenes obtained by
polymerization of a C.sub.4 refinery stream having a butene content
of 35 to 75% by wt., and an isobutene content of 30 to 60% by wt. A
preferred source of monomer for making poly-n-butenes is petroleum
feedstreams such as Raffinate II. These feed stocks are disclosed
in the art such as in U.S. Pat. No. 4,952,739. A preferred
embodiment utilizes polyisobutylene prepared from a pure
isobutylene stream or a Raffinate I stream to prepare reactive
isobutylene polymers with terminal vinylidene olefins.
Polyisobutene polymers that may be employed are generally based on
a polymer chain of from 1500 to 3000.
[0085] The dispersant(s) are preferably non-polymeric (e.g., mono-
or bis-succinimides). Such dispersants can be prepared by
conventional processes such as disclosed in U.S. Patent Application
Publication No. 2008/0020950, the disclosure of which is
incorporated herein by reference.
[0086] The dispersant(s) can be borated by conventional means, as
generally disclosed in U.S. Pat. Nos. 3,087,936, 3,254,025 and
5,430,105.
[0087] Such dispersants may be used in an amount of about 0.01 to
20 weight percent or 0.01 to 10 weight percent, preferably about
0.5 to 8 weight percent, or more preferably 0.5 to 4 weight
percent. Or such dispersants may be used in an amount of about 2 to
12 weight percent, preferably about 4 to 10 weight percent, or more
preferably 6 to 9 weight percent. On an active ingredient basis,
such additives may be used in an amount of about 0.06 to 14 weight
percent, preferably about 0.3 to 6 weight percent. The hydrocarbon
portion of the dispersant atoms can range from C.sub.60 to
C.sub.1000, or from C.sub.70 to C.sub.300, or from C.sub.70 to
C.sub.200. These dispersants may contain both neutral and basic
nitrogen, and mixtures of both. Dispersants can be end-capped by
borates and/or cyclic carbonates. Nitrogen content in the finished
oil can vary from about 200 ppm by weight to about 2000 ppm by
weight, preferably from about 200 ppm by weight to about 1200 ppm
by weight. Basic nitrogen can vary from about 100 ppm by weight to
about 1000 ppm by weight, preferably from about 100 ppm by weight
to about 600 ppm by weight.
[0088] Dispersants as described herein are beneficially useful with
the compositions of this disclosure and substitute for some or all
of the surfactants of this disclosure. Further, in one embodiment,
preparation of the compositions of this disclosure using one or
more dispersants is achieved by combining ingredients of this
disclosure, plus optional base stocks and lubricant additives, in a
mixture at a temperature above the melting point of such
ingredients, particularly that of the one or more M-carboxylates
(M=H, metal, two or more metals, mixtures thereof).
[0089] As used herein, the dispersant concentrations are given on
an "as delivered" basis. Typically, the active dispersant is
delivered with a process oil. The "as delivered" dispersant
typically contains from about 20 weight percent to about 80 weight
percent, or from about 40 weight percent to about 60 weight
percent, of active dispersant in the "as delivered" dispersant
product.
Detergents
[0090] Illustrative detergents useful in this disclosure include,
for example, alkali metal detergents, alkaline earth metal
detergents, or mixtures of one or more alkali metal detergents and
one or more alkaline earth metal detergents. A typical detergent is
an anionic material that contains a long chain hydrophobic portion
of the molecule and a smaller anionic or oleophobic hydrophilic
portion of the molecule. The anionic portion of the detergent is
typically derived from an organic acid such as a sulfur-containing
acid, carboxylic acid (e.g., salicylic acid), phosphorus-containing
acid, phenol, or mixtures thereof. The counterion is typically an
alkaline earth or alkali metal. The detergent can be overbased as
described herein.
[0091] The detergent is preferably a metal salt of an organic or
inorganic acid, a metal salt of a phenol, or mixtures thereof. The
metal is preferably selected from an alkali metal, an alkaline
earth metal, and mixtures thereof. The organic or inorganic acid is
selected from an aliphatic organic or inorganic acid, a
cycloaliphatic organic or inorganic acid, an aromatic organic or
inorganic acid, and mixtures thereof.
[0092] The metal is preferably selected from an alkali metal, an
alkaline earth metal, and mixtures thereof. More preferably, the
metal is selected from calcium (Ca), magnesium (Mg), and mixtures
thereof.
[0093] The organic acid or inorganic acid is preferably selected
from a sulfur-containing acid, a carboxylic acid, a
phosphorus-containing acid, and mixtures thereof.
[0094] Preferably, the metal salt of an organic or inorganic acid
or the metal salt of a phenol comprises calcium phenate, calcium
sulfonate, calcium salicylate, magnesium phenate, magnesium
sulfonate, magnesium salicylate, an overbased detergent, and
mixtures thereof.
[0095] Salts that contain a substantially stochiometric amount of
the metal are described as neutral salts and have a total base
number (TBN, as measured by ASTM D2896) of from 0 to 80. Many
compositions are overbased, containing large amounts of a metal
base that is achieved by reacting an excess of a metal compound (a
metal hydroxide or oxide, for example) with an acidic gas (such as
carbon dioxide). Useful detergents can be neutral, mildly
overbased, or highly overbased. These detergents can be used in
mixtures of neutral, overbased, highly overbased calcium
salicylate, sulfonates, phenates and/or magnesium salicylate,
sulfonates, phenates. The TBN ranges can vary from low, medium to
high TBN products, including as low as 0 to as high as 600.
Preferably the TBN delivered by the detergent is between 1 and 20.
More preferably between 1 and 12. Mixtures of low, medium, high TBN
can be used, along with mixtures of calcium and magnesium metal
based detergents, and including sulfonates, phenates, salicylates,
and carboxylates. A detergent mixture with a metal ratio of 1, in
conjunction of a detergent with a metal ratio of 2, and as high as
a detergent with a metal ratio of 5, can be used. Borated
detergents can also be used.
[0096] Alkaline earth phenates are another useful class of
detergent. These detergents can be made by reacting alkaline earth
metal hydroxide or oxide (CaO, Ca(OH).sub.2, BaO, Ba(OH).sub.2,
MgO, Mg(OH).sub.2, for example) with an alkyl phenol or sulfurized
alkylphenol. Useful alkyl groups include straight chain or branched
C.sub.1-C.sub.30 alkyl groups, preferably, C.sub.4-C.sub.20 or
mixtures thereof. Examples of suitable phenols include
isobutylphenol, 2-ethylhexylphenol, nonylphenol, dodecyl phenol,
and the like. It should be noted that starting alkylphenols may
contain more than one alkyl substituent that are each independently
straight chain or branched and can be used from 0.5 to 6 weight
percent. When a non-sulfurized alkylphenol is used, the sulfurized
product may be obtained by methods well known in the art. These
methods include heating a mixture of alkylphenol and sulfurizing
agent (including elemental sulfur, sulfur halides such as sulfur
dichloride, and the like) and then reacting the sulfurized phenol
with an alkaline earth metal base.
[0097] In accordance with this disclosure, metal salts of
carboxylic acids are preferred detergents. These carboxylic acid
detergents may be prepared by reacting a basic metal compound with
at least one carboxylic acid and removing free water from the
reaction product. These compounds may be overbased to produce the
desired TBN level. Detergents made from salicylic acid are one
preferred class of detergents derived from carboxylic acids. Useful
salicylates include long chain alkyl salicylates. One useful family
of compositions is of the formula
##STR00001##
where R is an alkyl group having 1 to about 30 carbon atoms, n is
an integer from 1 to 4, and M is an alkaline earth metal. Preferred
R groups are alkyl chains of at least C.sub.11, preferably C.sub.13
or greater. R may be optionally substituted with substituents that
do not interfere with the detergent's function. M is preferably,
calcium, magnesium, barium, or mixtures thereof. More preferably, M
is calcium.
[0098] Hydrocarbyl-substituted salicylic acids may be prepared from
phenols by the Kolbe reaction (see U.S. Pat. No. 3,595,791). The
metal salts of the hydrocarbyl-substituted salicylic acids may be
prepared by double decomposition of a metal salt in a polar solvent
such as water or alcohol.
[0099] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0100] Detergents may be simple detergents or what is known as
hybrid or complex detergents. The latter detergents can provide the
properties of two detergents without the need to blend separate
materials. See U.S. Pat. No. 6,034,039.
[0101] Preferred detergents include calcium sulfonates, magnesium
sulfonates, calcium salicylates, magnesium salicylates, calcium
phenates, magnesium phenates, and other related components
(including borated detergents), and mixtures thereof. Preferred
mixtures of detergents include magnesium sulfonate and calcium
salicylate, magnesium sulfonate and calcium sulfonate, magnesium
sulfonate and calcium phenate, calcium phenate and calcium
salicylate, calcium phenate and calcium sulfonate, calcium phenate
and magnesium salicylate, calcium phenate and magnesium phenate.
Overbased detergents are also preferred.
[0102] The detergent concentration in the lubricating oils of this
disclosure can range from about 0.5 to about 6.0 weight percent,
preferably about 0.6 to 5.0 weight percent, and more preferably
from about 0.8 weight percent to about 4.0 weight percent, based on
the total weight of the lubricating oil.
[0103] As used herein, the detergent concentrations are given on an
"as delivered" basis. Typically, the active detergent is delivered
with a process oil. The "as delivered" detergent typically contains
from about 20 weight percent to about 100 weight percent, or from
about 40 weight percent to about 60 weight percent, of active
detergent in the "as delivered" detergent product.
Viscosity Index Improvers
[0104] Viscosity index improvers (also known as VI improvers,
viscosity modifiers, and viscosity improvers) can be included in
the lubricant compositions of this disclosure.
[0105] Viscosity index improvers provide lubricants with high and
low temperature operability. These additives impart shear stability
at elevated temperatures and acceptable viscosity at low
temperatures.
[0106] Suitable viscosity index improvers include high molecular
weight hydrocarbons, polyesters and viscosity index improver
dispersants that function as both a viscosity index improver and a
dispersant. Typical molecular weights of these polymers are between
about 10,000 to 1,500,000, more typically about 20,000 to
1,200,000, and even more typically between about 50,000 and
1,000,000.
[0107] Examples of suitable viscosity index improvers are linear or
star-shaped polymers and copolymers of methacrylate, butadiene,
olefins, or alkylated styrenes. Polyisobutylene is a commonly used
viscosity index improver. Another suitable viscosity index improver
is polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity index improvers
include copolymers of ethylene and propylene, hydrogenated block
copolymers of styrene and isoprene, and polyacrylates (copolymers
of various chain length acrylates, for example). Specific examples
include styrene-isoprene or styrene-butadiene based polymers of
50,000 to 200,000 molecular weight.
[0108] Olefin copolymers, are commercially available from Chevron
Oronite Company LLC under the trade designation "PARATONE.RTM."
(such as "PARATONE.RTM. 8921" and "PARATONE.RTM. 8941"); from Afton
Chemical Corporation under the trade designation "HiTEC.RTM." (such
as "HiTEC.RTM. 5850B"; and from The Lubrizol Corporation under the
trade designation "Lubrizol.RTM. 7067C". Polyisoprene polymers are
commercially available from Infineum International Limited, e.g.
under the trade designation "SV200"; diene-styrene copolymers are
commercially available from Infineum International Limited, e.g.
under the trade designation "SV 260".
[0109] In an embodiment of this disclosure, the viscosity index
improvers may be used in an amount of less than about 2.0 weight
percent, preferably less than about 1.0 weight percent, and more
preferably less than about 0.5 weight percent, based on the total
weight of the formulated oil or lubricating engine oil. Viscosity
improvers are typically added as concentrates, in large amounts of
diluent oil.
[0110] In another embodiment of this disclosure, the viscosity
index improvers may be used in an amount of from 0.25 to about 2.0
weight percent, preferably 0.15 to about 1.0 weight percent, and
more preferably 0.05 to about 0.5 weight percent, based on the
total weight of the formulated oil or lubricating engine oil.
Antioxidants
[0111] Antioxidants retard the oxidative degradation of base oils
during service. Such degradation may result in deposits on metal
surfaces, the presence of sludge, or a viscosity increase in the
lubricant. One skilled in the art knows a wide variety of oxidation
inhibitors that are useful in lubricating oil compositions. See,
Klamann in Lubricants and Related Products, op cite, and U.S. Pat.
Nos. 4,798,684 and 5,084,197, for example.
[0112] Useful antioxidants include hindered phenols. These phenolic
antioxidants may be ashless (metal-free) phenolic compounds or
neutral or basic metal salts of certain phenolic compounds. Typical
phenolic antioxidant compounds are the hindered phenolics which are
the ones which contain a sterically hindered hydroxyl group, and
these include those derivatives of dihydroxy aryl compounds in
which the hydroxyl groups are in the o- or p-position to each
other. Typical phenolic antioxidants include the hindered phenols
substituted with C.sub.6+ alkyl groups and the alkylene coupled
derivatives of these hindered phenols. Examples of phenolic
materials of this type 2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl
phenol; 2-t-butyl-4-dodecyl phenol; 2,6-di-t-butyl-4-heptyl phenol;
2,6-di-t-butyl-4-dodecyl phenol; 2-methyl-6-t-butyl-4-heptyl
phenol; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic propionic ester derivatives.
Bis-phenolic antioxidants may also be advantageously used in
combination with the instant disclosure. Examples of ortho-coupled
phenols include: 2,2'-bis(4-heptyl-6-t-butyl-phenol);
2,2'-bis(4-octyl-6-t-butyl-phenol); and
2,2'-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0113] Effective amounts of one or more catalytic antioxidants may
also be used. The catalytic antioxidants comprise an effective
amount of a) one or more oil soluble polymetal organic compounds;
and, effective amounts of b) one or more substituted
N,N'-diaryl-o-phenylenediamine compounds or c) one or more hindered
phenol compounds; or a combination of both b) and c). Catalytic
antioxidants are more fully described in U.S. Pat. No. 8,048,833,
herein incorporated by reference in its entirety.
[0114] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: alkylated and non-alkylated aromatic amines
such as aromatic monoamines of the formula R.sup.8R.sup.9R.sup.10N
where R.sup.8 is an aliphatic, aromatic or substituted aromatic
group, R.sup.9 is an aromatic or a substituted aromatic group, and
R.sup.10 is H, alkyl, aryl or R.sup.11S(O).sub.xR.sup.12 where
R.sup.11 is an alkylene, alkenylene, or aralkylene group, R.sup.12
is a higher alkyl group, or an alkenyl, aryl, or alkaryl group, and
x is 0, 1 or 2. The aliphatic group R.sup.8 may contain from 1 to
20 carbon atoms, and preferably contains from 6 to 12 carbon atoms.
The aliphatic group is a saturated aliphatic group. Preferably,
both R.sup.8 and R.sup.9 are aromatic or substituted aromatic
groups, and the aromatic group may be a fused ring aromatic group
such as naphthyl. Aromatic groups R.sup.8 and R.sup.9 may be joined
together with other groups such as S.
[0115] Typical aromatic amines antioxidants have alkyl substituent
groups of at least 6 carbon atoms. Examples of aliphatic groups
include hexyl, heptyl, octyl, nonyl, and decyl. Generally, the
aliphatic groups will not contain more than 14 carbon atoms. The
general types of amine antioxidants useful in the present
compositions include diphenylamines, phenyl naphthylamines,
phenothiazines, imidodibenzyls and diphenyl phenylene diamines.
Mixtures of two or more aromatic amines are also useful. Polymeric
amine antioxidants can also be used. Particular examples of
aromatic amine antioxidants useful in the present disclosure
include: p,p'-dioctyldiphenylamine;
t-octylphenyl-alpha-naphthylamine; phenyl-alphanaphthylamine; and
p-octylphenyl-alpha-naphthylamine.
[0116] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0117] Preferred antioxidants include hindered phenols, arylamines.
These antioxidants may be used individually by type or in
combination with one another. Such additives may be used in an
amount of 0.01 to 5 weight percent, preferably 0.01 to 2 weight
percent, more preferably zero to 1.5 weight percent, more
preferably zero to less than 1 weight percent.
Pour Point Depressants (PPDs)
[0118] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the compositions of the present
disclosure if desired. These pour point depressant may be added to
lubricating compositions of the present disclosure to lower the
minimum temperature at which the fluid will flow or can be poured.
Examples of suitable pour point depressants include
polymethacrylates, polyacrylates, polyarylamides, condensation
products of haloparaffin waxes and aromatic compounds, vinyl
carboxylate polymers, and terpolymers of dialkylfumarates, vinyl
esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655,479; 2,666,746;
2,721,877; 2,721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof. Such additives may be
used in an amount of about 0.01 to 5 weight percent, preferably
about 0.01 to 1.5 weight percent.
Seal Compatibility Agents
[0119] Seal compatibility agents help to swell elastomeric seals by
causing a chemical reaction in the fluid or physical change in the
elastomer. Suitable seal compatibility agents for lubricating oils
include organic phosphates, alkoxysulfolanes, aromatic esters,
aromatic hydrocarbons, esters (butylbenzyl phthalate, for example),
and polybutenyl succinic anhydride. Such additives may be used in
an amount of about 0.01 to 3 weight percent, preferably about 0.01
to 2 weight percent.
Antifoam Agents
[0120] Anti-foam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical anti-foam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Anti-foam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers; usually
the amount of these additives combined is less than 1 weight
percent and often less than 0.1 weight percent.
Inhibitors and Antirust Additives
[0121] Antirust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. A wide variety of these are
commercially available.
[0122] One type of antirust additive is a polar compound that wets
the metal surface preferentially, protecting it with a film of oil.
Another type of antirust additive absorbs water by incorporating it
in a water-in-oil emulsion so that only the oil touches the metal
surface. Yet another type of antirust additive chemically adheres
to the metal to produce a non-reactive surface. Examples of
suitable additives include zinc dithiophosphates, metal phenolates,
basic metal sulfonates, fatty acids and amines. Such additives may
be used in an amount of about 0.01 to 5 weight percent, preferably
about 0.01 to 1.5 weight percent.
Friction Modifiers
[0123] A friction modifier is any material or materials that can
alter the coefficient of friction of a surface lubricated by any
lubricant or fluid containing such material(s). Friction modifiers,
also known as friction reducers, or lubricity agents or oiliness
agents, and other such agents that change the ability of base oils,
formulated lubricant compositions, or functional fluids, to modify
the coefficient of friction of a lubricated surface may be
effectively used in combination with the base oils or lubricant
compositions of the present disclosure if desired. Friction
modifiers that lower the coefficient of friction are particularly
advantageous in combination with the base oils and lube
compositions of this disclosure.
[0124] Illustrative friction modifiers may include, for example,
organometallic compounds or materials, or mixtures thereof.
Illustrative organometallic friction modifiers useful in the
lubricating engine oil formulations of this disclosure include, for
example, molybdenum amine, molybdenum diamine, an
organotungstenate, a molybdenum dithiocarbamate, molybdenum
dithiophosphates, molybdenum amine complexes, molybdenum
carboxylates, and the like, and mixtures thereof. Similar tungsten
based compounds may be preferable.
[0125] Other illustrative friction modifiers useful in the
lubricating engine oil formulations of this disclosure include, for
example, alkoxylated fatty acid esters, alkanolamides, polyol fatty
acid esters, borated glycerol fatty acid esters, fatty alcohol
ethers, and mixtures thereof.
[0126] Illustrative alkoxylated fatty acid esters include, for
example, polyoxyethylene stearate, fatty acid polyglycol ester, and
the like. These can include polyoxypropylene stearate,
polyoxybutylene stearate, polyoxyethylene isosterate,
polyoxypropylene isostearate, polyoxyethylene palmitate, and the
like.
[0127] Illustrative alkanolamides include, for example, lauric acid
diethylalkanolamide, palmic acid diethylalkanolamide, and the like.
These can include oleic acid diethyalkanolamide, stearic acid
diethylalkanolamide, oleic acid diethylalkanolamide,
polyethoxylated hydrocarbylamides, polypropoxylated
hydrocarbylamides, and the like.
[0128] Illustrative polyol fatty acid esters include, for example,
glycerol mono-oleate, saturated mono-, di-, and tri-glyceride
esters, glycerol mono-stearate, and the like. These can include
polyol esters, hydroxyl-containing polyol esters, and the like.
[0129] Illustrative borated glycerol fatty acid esters include, for
example, borated glycerol mono-oleate, borated saturated mono-,
di-, and tri-glyceride esters, borated glycerol mono-sterate, and
the like. In addition to glycerol polyols, these can include
trimethylolpropane, pentaerythritol, sorbitan, and the like. These
esters can be polyol monocarboxylate esters, polyol dicarboxylate
esters, and on occasion polyoltricarboxylate esters. Preferred can
be the glycerol mono-oleates, glycerol dioleates, glycerol
trioleates, glycerol monostearates, glycerol distearates, and
glycerol tristearates and the corresponding glycerol
monopalmitates, glycerol dipalmitates, and glycerol tripalmitates,
and the respective isostearates, linoleates, and the like. On
occasion the glycerol esters can be preferred as well as mixtures
containing any of these. Ethoxylated, propoxylated, butoxylated
fatty acid esters of polyols, especially using glycerol as
underlying polyol can be preferred.
[0130] Illustrative fatty alcohol ethers include, for example,
stearyl ether, myristyl ether, and the like. Alcohols, including
those that have carbon numbers from C.sub.3 to C.sub.50, can be
ethoxylated, propoxylated, or butoxylated to form the corresponding
fatty alkyl ethers. The underlying alcohol portion can preferably
be stearyl, myristyl, C.sub.11-C.sub.13 hydrocarbon, oleyl,
isosteryl, and the like.
[0131] Useful concentrations of friction modifiers may range from
0.01 weight percent to 5 weight percent, or about 0.1 weight
percent to about 2.5 weight percent, or about 0.1 weight percent to
about 1.5 weight percent, or about 0.1 weight percent to about 1
weight percent. Concentrations of molybdenum-containing materials
are often described in terms of Mo metal concentration.
Advantageous concentrations of Mo may range from 25 ppm to 700 ppm
or more, and often with a preferred range of 50-200 ppm. Friction
modifiers of all types may be used alone or in mixtures with the
materials of this disclosure. Often mixtures of two or more
friction modifiers, or mixtures of friction modifier(s) with
alternate surface active material(s), are also desirable.
[0132] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
disclosure are shown in Table 1 below.
[0133] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
Accordingly, the weight amounts in the table below, as well as
other amounts mentioned herein, are directed to the amount of
active ingredient (that is the non-diluent portion of the
ingredient). The weight percent (wt %) indicated below is based on
the total weight of the lubricating oil composition.
TABLE-US-00002 TABLE 1 Typical Amounts of Other Lubricating Oil
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Dispersant 0.1-20 0.1-8 Detergent 0.1-20 0.1-8 Friction
Modifier 0.01-5 0.01-1.5 Antioxidant 0.1-5 0.1-1.5 Pour Point
Depressant (PPD) 0.0-5 0.01-1.5 Anti-foam Agent 0.001-3 0.001-0.15
Viscosity Index Improver 0.1-2 0.1-1 (solid polymer basis)
Anti-wear 0.1-2 0.5-1 Inhibitor and Antirust 0.01-5 0.01-1.5
[0134] The foregoing additives are all commercially available
materials. These additives may be added independently but are
usually precombined in packages which can be obtained from
suppliers of lubricant oil additives. Additive packages with a
variety of ingredients, proportions and characteristics are
available and selection of the appropriate package will take the
requisite use of the ultimate composition into account.
[0135] Different engine hardware and control schemes can
significantly influence the occurrence of LSPI. See, for example,
U.S. Patent Application Publication Nos. 2012/1866225 and
2003/0908070, and also SAE 2012-02-1148, which are all incorporated
herein by reference. For example, a 2.0 L, 4-cylinder TGDI GM
Ecotec engine can be used for LSPI testing. A six segment test
procedure can be used to determine the number of LSPI events that
occur at two different specified engine load and speed conditions.
Each segment of the test procedure comprises 25,000 engine cycles,
where one cycle corresponds to 720 degrees of crank shaft rotation.
The first set of conditions is 2000 RPM and 18 bar BMEP, hereafter
referred to as "High Load". The second set of conditions is 1500
RPM and 12.5 bar BMEP, hereafter referred to as "Low Load". The
test procedure comprises two segments of High Load, followed by two
segments of Low Load, followed by two segments of High Load. A 30
minute warm up at 2000 RPM and 4 bar BMEP is also conducted prior
to commencing the test procedure. This test procedure is repeated
four times for each of the lubricants tested. LSPI events are
counted during the High Load segments only, using pressure
transducers placed in each of the 4 cylinders to monitor the peak
cylinder pressure. Peak pressures in the cylinder that are greater
than 4.7 standard deviations above the mean peak cylinder pressure,
or more than 4.7 standard deviations below the mean peak cylinder
pressure are counted as an LSPI event.
[0136] In accordance with this disclosure, the engine can exhibit
greater than about 10%, or greater than about 25%, reduced low
speed pre-ignition, based on normalized low speed pre-ignition
(LSPI) counts per 25,000 engine cycles, engine operation at 2000
revolutions per minute (RPM) and brake mean effective pressure
(BMEP) at 18 bar, as compared to low speed pre-ignition performance
achieved in an engine using a lubricating oil containing calcium or
magnesium.
[0137] The following non-limiting examples are provided to
illustrate the disclosure.
Examples
[0138] Formulations were prepared as simple blends with 10% carbon
black (Cabot Vulcan XC72R), a metal oxide, and base stock (balance)
as shown in FIGS. 1-3. All of the ingredients used herein are
commercially available.
[0139] Testing was conducted for the formulations as described in
Ko Onodera et al., Engine Oil Formulation Technology to Prevent
Pre-ignition in Turbocharged Direct Injection Spark Ignition
Engines, JSAE 20159071, SAE 2015-01-2027, incorporated herein by
reference. The testing compared LSPI engine test results to
thermogravimetric analysis (TGA) decomposition temperatures. The
carbon black decomposition temperature was defined as the
temperature at which 50% mass decrease between 400.degree. C. and
800.degree. C. was observed. The carbon black decomposition
temperature is an indicator of the catalytic activity of the metal
oxide for promoting auto-ignition. An increase in the decomposition
temperature of a lubricant corresponds to an increase of the
auto-ignition temperature of the LSPI precursors resulting in less
LSPI activity. TGA was run according to the conditions listed in
Table 2 below.
TABLE-US-00003 TABLE 2 Temperature 25 .degree.C.-800 .degree.C.
Temperature increase rate 10 .degree.C./min Atmosphere Air Sample
pan Pt
[0140] For purposes of this disclosure, the above testing is
referred to as the Thermogravimetric Engine Oil Simulation
Test.
[0141] For comparative purposes, results were generated that match
those disclosed in Onodera et al.
[0142] In addition, various other metal oxides were tested. The
results show that metal oxides can alter the carbon black
decomposition temperatures by up to 250.degree. C. (see FIG. 1).
FIG. 1 shows carbon decomposition temperatures of various metal
oxides in a carbon black/PAO mixture. Most notable among the oxide
results are sodium, manganese, titanium, and aluminum. These four
metals show low catalytic activity, even below that of magnesium,
which in the form of a detergent, is well known to have
significantly lower LSPI activity than calcium detergents.
[0143] Simplified lubricating oil blends were prepared as shown in
FIGS. 2 and 3. The blends contained only base stock, carbon black,
and metal oxide. All of the ingredients used herein are
commercially available. Group III, IV, and V base stocks were used
in the formulations.
[0144] FIG. 2 shows carbon decomposition temperatures of various
metal oxides in a carbon black/base stock mixture in which barium
oxide and titanium(IV) oxide and various base stocks were used.
Barium oxide was selected because of its poor performance while
titanium(IV) oxide was selected for its strong performance. Base
stock selection impacted the decomposition temperature with Visom
(Group III) performing the worst, EHC (Group II) in the middle, and
GTL and PAO (Group III+ and Group IV) having the highest
decomposition temperatures. Titanium has higher decomposition
temperatures than barium across the spectrum and also has less
variability between the different base stocks.
[0145] FIG. 3 shows carbon decomposition temperatures of various
metal oxides in a carbon black/formulated mixture in which barium
and titanium and PAO base stock were used with varying
concentrations of metal oxide. Titanium has higher decomposition
temperatures than barium, and both sets of samples remain fairly
constant regardless of concentration.
[0146] The forgoing examples have shown that various metal oxides
demonstrate low catalytic activity which leads to improved LSPI
performance in an engine.
PCT and EP Clauses:
[0147] 1. A method for preventing or reducing low speed
pre-ignition in an engine lubricated with a lubricating oil by
using as the lubricating oil a formulated oil, said formulated oil
having a composition comprising a lubricating oil base stock as a
major component; and at least one lubricating oil additive, as a
minor component; wherein said lubricating oil contains at least one
metal or metalloid in an amount sufficient that, in
thermogravimetric measurements of the lubricating oil by a
Thermogravimetric Engine Oil Simulation Test, carbon black
decomposition temperature is increased as compared to the carbon
black decomposition temperature in a lubricating oil containing
calcium or magnesium.
[0148] 2. The method of clause 1 wherein, in thermogravimetric
measurements of the lubricating oil by a Thermogravimetric Engine
Oil Simulation Test, the carbon black decomposition temperature is
increased by at least 10.degree. C. as compared to the carbon black
decomposition temperature in a lubricating oil containing calcium
or magnesium.
[0149] 3. The method of clause 1 wherein, in thermogravimetric
measurements of the lubricating oil by a Thermogravimetric Engine
Oil Simulation Test, the carbon black decomposition temperature is
increased by at least 25.degree. C. as compared to the carbon black
decomposition temperature in a lubricating oil containing calcium
or magnesium.
[0150] 4. The method of clause 1 wherein the engine exhibits
greater than 10% reduced low speed pre-ignition, based on
normalized low speed pre-ignition (LSPI) counts per 25,000 engine
cycles, engine operation at 2000 revolutions per minute (RPM) and
brake mean effective pressure (BMEP) at 18 bar, as compared to low
speed pre-ignition performance achieved in an engine using a
lubricating oil containing calcium or magnesium.
[0151] 5. The method of clauses 1-4 wherein the at least one metal
or metalloid comprises sodium, manganese, titanium, aluminum, or
mixtures thereof.
[0152] 6. The method of clauses 1-5 wherein the at least one metal
or metalloid is present in the lubricating oil in an amount from
100 ppm to 25,000 ppm.
[0153] 7. The method of clauses 1-6 wherein (i) the at least one
metal or metalloid is present in the lubricating oil in an amount
from 100 ppm to 1000 ppm; (ii) total base number (TBN), as measured
by ASTM D2896, of the lubricating oil ranges from 2 mg KOH to 17 mg
KOH; (iii) total sulfated ash of the lubricating oil ranges from
0.01 to 1 wt %.
[0154] 8. A lubricating engine oil having a composition comprising
a lubricating oil base stock as a major component; and at least one
lubricating oil additive, as a minor component; wherein said
lubricating engine oil contains at least one metal or metalloid in
an amount sufficient that, in thermogravimetric measurements of the
lubricating engine oil by a Thermogravimetric Engine Oil Simulation
Test, carbon black decomposition temperature is increased as
compared to the carbon black decomposition temperature in a
lubricating engine oil containing calcium or magnesium.
[0155] 9. The lubricating engine oil of clause 8 wherein, in
thermogravimetric measurements of the lubricating engine oil by a
Thermogravimetric Engine Oil Simulation Test, the carbon black
decomposition temperature is increased by at least 10.degree. C. as
compared to the carbon black decomposition temperature in a
lubricating engine oil containing calcium or magnesium.
[0156] 10. The lubricating engine oil of clause 8 wherein, in
thermogravimetric measurements of the lubricating engine oil by a
Thermogravimetric Engine Oil Simulation Test, the carbon black
decomposition temperature is increased by at least 25.degree. C. as
compared to the carbon black decomposition temperature in a
lubricating engine oil containing calcium or magnesium.
[0157] 11. The lubricating engine oil of clause 8 wherein the
engine exhibits greater than 10% reduced low speed pre-ignition,
based on normalized low speed pre-ignition (LSPI) counts per 25,000
engine cycles, engine operation at 2000 revolutions per minute
(RPM) and brake mean effective pressure (BMEP) at 18 bar, as
compared to low speed pre-ignition performance achieved in an
engine using a lubricating engine oil containing calcium or
magnesium.
[0158] 12. The lubricating engine oil of clauses 8-11 wherein the
at least one metal or metalloid comprises sodium, manganese,
titanium, aluminum, or mixtures thereof.
[0159] 13. The lubricating engine oil of clauses 8-12 wherein the
at least one metal or metalloid is present in the lubricating
engine oil in an amount from 100 ppm to 25,000 ppm.
[0160] 14. The lubricating engine oil of clauses 8-13 wherein (i)
the at least one metal or metalloid is present in the lubricating
engine oil in an amount from 100 ppm to 1000 ppm; (ii) total base
number (TBN), as measured by ASTM D2896, of the lubricating engine
oil ranges from 2 mg KOH to 17 mg KOH; (iii) total sulfated ash of
the lubricating engine oil ranges from 0.01 to 0.17 wt %.
[0161] 15. The lubricating engine oil of clauses 8-14 wherein the
at least one lubricating oil additive has a total sulfated ash from
0.02 to 0.17 wt %.
[0162] All patents and patent applications, test procedures (such
as ASTM methods, UL methods, and the like), and other documents
cited herein are fully incorporated by reference to the extent such
disclosure is not inconsistent with this disclosure and for all
jurisdictions in which such incorporation is permitted.
[0163] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0164] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims
* * * * *
References