U.S. patent application number 17/580184 was filed with the patent office on 2022-05-05 for lubricant compositions for direct injection engines.
This patent application is currently assigned to The Lubrizol Corporation. The applicant listed for this patent is The Lubrizol Corporation. Invention is credited to Jeffry G. Dietz, Patrick E. Mosier, Alexander Sammut.
Application Number | 20220135898 17/580184 |
Document ID | / |
Family ID | |
Filed Date | 2022-05-05 |
United States Patent
Application |
20220135898 |
Kind Code |
A1 |
Mosier; Patrick E. ; et
al. |
May 5, 2022 |
Lubricant Compositions For Direct Injection Engines
Abstract
The invention is directed to a method for reducing low speed
pre-ignition events in a spark-ignited direct injection internal
combustion engine by supplying to the sump a lubricant composition
which contains an oil of lubricating viscosity and a metal
overbased detergent. The metal overbased detergent may be selected
from sulfonate detergents, phenate detergents, and salicylate
detergents, especially sulfonate detergents with a metal ratio of
at least 5.
Inventors: |
Mosier; Patrick E.; (Bay
Village, OH) ; Dietz; Jeffry G.; (Shaker Heights,
OH) ; Sammut; Alexander; (Chardon, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Lubrizol Corporation |
Wickliffe |
OH |
US |
|
|
Assignee: |
The Lubrizol Corporation
Wickliffe
OH
|
Appl. No.: |
17/580184 |
Filed: |
January 20, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16668152 |
Oct 30, 2019 |
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17580184 |
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15022345 |
Mar 16, 2016 |
10494584 |
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16668152 |
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61879725 |
Sep 19, 2013 |
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International
Class: |
C10M 169/04 20060101
C10M169/04; C10M 163/00 20060101 C10M163/00 |
Claims
1. A lubricant composition comprising: (a) a base oil of
lubricating viscosity; (b) at least one magnesium overbased
detergent in an amount to provide at least 450 ppm magnesium from
the magnesium overbased detergent to the lubricating composition;
(c) at least one calcium sulfonate overbased detergent in an amount
to provide at least 1,000 ppm calcium to the lubricating
composition; and (d) 0.5 to 0.9 wt. % of a zinc
dialkyldithiophosphate anti-wear additive, wherein the magnesium
overbased detergent and the calcium overbased detergent
collectively contribute up to about 0.9 weight percent of sulfated
ash to the lubricating composition and wherein the lubricating
composition has a phosphorus content of 0.12 wt. % or less and
total sulfated ash of 1.1% or less.
2. The composition of claim 1, further comprising one or more
additional additives is selected from an ashless dispersant, an
ashless antioxidant, a friction modifier, and a polymeric viscosity
modifier.
3. The composition of claim 1, wherein the magnesium overbased
detergent has a metal ratio of 5 to 30.
4. The composition of claim 2, wherein the one or more additional
additives includes a polyalkenyl succinimide dispersant in an
amount from 0.5 to 4 weight % of the lubricating composition.
5. The composition of claim 2, wherein the one or more additional
additives includes a boron post-treated polyalkenyl succinimide
dispersant.
6. The composition of claim 2, wherein the one or more additional
additives includes a molybdenum compound in an amount to deliver 20
to 750 ppm molybdenum.
7. The method of claim 1, wherein the base oil comprises at least
50 weight % of a Group II base oil, a Group III base oil, or
mixtures thereof.
8. The composition of claim 1, wherein the one or more additional
additives includes an ashless antioxidant present in the
lubricating composition in an amount of from 0.3 weight % to 5
weight %.
9. The composition of claim 8, wherein the ashless antioxidant is
selected from one or more of arylamines, diarylamines, alkylated
arylamines, alkylated diaryl amines, phenols, hindered phenols,
sulfurized olefins, or mixtures thereof.
10. The composition of claim 1, wherein the magnesium overbased
detergent is selected from one or more of a magnesium sulfonate
detergent and a magnesium saligenin detergent.
11. A lubricant composition comprising: (a) a base oil of
lubricating viscosity; (b) at least one magnesium overbased
detergent in an amount to provide at least 450 ppm magnesium from
the magnesium overbased detergent to the lubricating composition;
(c) at least one calcium overbased detergent in an amount to
provide at least 1,000 ppm calcium to the lubricating composition;
and (d) 0.5 to 0.9 wt. % of a zinc dialkyldithiophosphate anti-wear
additive, wherein the magnesium overbased detergent and the calcium
overbased detergent collectively contribute up to about 0.9 weight
percent of sulfated ash to the lubricating composition and wherein
the lubricating composition has a phosphorus content of 0.12 wt. %
or less and total sulfated ash of 1.1% or less, where the lubricant
composition is capable of reducing low speed pre-ignition events in
a spark-ignited direct injection internal combustion engine
equipped with a turbocharger and operated under a load with a brake
mean effective pressure (BMEP) of greater than or equal to 12 bars
at speeds less than or equal to 3,000 rpm.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. Ser. No.
16/668,152 filed on Oct. 30, 2019, which is a continuation of U.S.
Ser. No. 15/022,345 filed on Mar. 16, 2016, now U.S. Pat. No.
10,494,584, which claims priority PCT/US2014/056445 filed on Sep.
19, 2014, which claims benefit of U.S. Provisional Application Ser.
No. 61/879,725 filed on Sep. 19, 2013.
BACKGROUND OF THE INVENTION
[0002] The disclosed technology relates to lubricants for internal
combustion engines, particularly those for spark-ignited direct
injection engines.
[0003] Modern engine designs are being developed to improve fuel
economy without sacrificing performance or durability.
Historically, gasoline was port-fuel injected (PFI), that is,
injected through the air intake and entering the combustion chamber
via the air intake valve. Gasoline direct injection (GDI) involves
direct injection of gasoline into the combustion chamber.
[0004] In certain situations, the internal combustion engine may
exhibit abnormal combustion. Abnormal combustion in a
spark-initiated internal combustion engine may be understood as an
uncontrolled explosion occurring in the combustion chamber as a
result of ignition of combustible elements therein by a source
other than the igniter.
[0005] Pre-ignition may be understood as an abnormal form of
combustion resulting from ignition of the air-fuel mixture prior to
ignition by the igniter. Anytime the air-fuel mixture in the
combustion chamber is ignited prior to ignition by the igniter,
such may be understood as pre-ignition.
[0006] Without being bound to a particular theory, traditionally,
pre-ignition has occurred during high speed operation of an engine
when a particular point within the combustion chamber of a cylinder
may become hot enough during high speed operation of the engine to
effectively function as a glow plug (e.g. overheated spark plug
tip, overheated burr of metal) to provide a source of ignition
which causes the air-fuel mixture to ignite before ignition by the
igniter. Such pre-ignition may be more commonly referred to as
hot-spot pre-ignition and may be inhibited by simply locating the
hot spot and eliminating it.
[0007] More recently, vehicle manufacturers have observed
intermittent abnormal combustion in their production of
turbocharged gasoline engines, particularly at low speeds and
medium-to-high loads. More particularly, when operating the engine
at speeds less than or equal to 3,000 rpm and under a load with a
break mean effective pressure (BMEP) of greater than or equal to 10
bars, a condition which may be referred to as low-speed
pre-ignition (LSPI) may occur in a very random and stochastic
fashion.
[0008] The disclosed technology provides a method for reducing,
inhibiting, or even eliminating LSPI events in direct injection
engines by operating the engines with a lubricant that contains a
metal overbased detergent.
SUMMARY OF THE INVENTION
[0009] The disclosed technology provides a method for reducing low
speed pre-ignition events in a spark-ignited direct injection
internal combustion engine comprising supplying to the sump a
lubricant composition which contains an oil of lubricating
viscosity and a metal overbased detergent. The metal overbased
detergent may be selected from sulfonate detergents, phenate
detergents, and salicylate detergents, especially sulfonate
detergents.
[0010] The invention provides method for reducing low speed
pre-ignition events in a spark-ignited direct injection internal
combustion engine comprising supplying to the engine a lubricant
composition comprising a base oil of lubricating viscosity and a
metal overbased detergent.
[0011] The invention further provides the method described herein
in which the engine is operated under a load with a break mean
effective pressure (BMEP) of greater than or equal to 10 bars.
[0012] The invention further provides the method described herein
in which the engine is operated at speeds less than or equal to
3,000 rpm.
[0013] The invention further provides the method described herein
in which the engine is fueled with a liquid hydrocarbon fuel, a
liquid nonhydrocarbon fuel, or mixtures thereof.
[0014] The invention further provides the method described herein
in which the engine is fueled by natural gas, liquefied petroleum
gas (LPG), compressed natural gas (CNG), or mixtures thereof.
[0015] The invention further provides the method described herein
in which the metal overbased detergent includes one or more of a
sulfonate detergent, a phenate detergent, a salicylate detergent,
and combinations thereof.
[0016] The invention further provides the method described herein
in which the lubricant composition further includes at least one
other additive selected from an ashless dispersant, an ashless
antioxidant, a phosphorus-containing anti-wear additive, a friction
modifier, and a polymeric viscosity modifier.
[0017] The invention further provides the method described herein
in which the metal overbased detergent comprises a sulfonate
detergent.
[0018] The invention further provides the method described herein
in which the metal overbased detergent comprises a salicylate
detergent.
[0019] The invention further provides the method described herein
in which the metal overbased detergent comprises an alkali metal or
an alkaline earth metal detergent.
[0020] The invention further provides the method described herein
in which the metal overbased detergent has a metal ratio of 5 to
30.
[0021] The invention further provides the method described herein
in which the metal overbased detergent is present in an amount from
0.2 to 8 weight percent of the lubricant composition.
[0022] The invention further provides the method described herein
in which the lubricating composition further includes a polyalkenyl
succinimide dispersant in an amount from 0.5 to 4 weight % of the
composition.
[0023] The invention further provides the method described herein
in which the lubricating composition includes at least 50 weight %
of a Group II base oil, a Group III base oil, or mixtures
thereof.
[0024] The invention further provides the method described herein
in which the metal overbased detergent comprises a sulfur-coupled
phenate detergent.
[0025] The invention further provides the method described herein
in which the metal overbased detergent is present in an amount to
provide 0.1 weight percent to 0.9 weight percent sulfated ash to
the lubricating composition.
[0026] The invention further provides the method described herein
in which there is a reduction in the number of LSPI events of at
least 10 percent.
[0027] The invention further provides the method described herein
in which the low speed pre-ignition events are reduced to less than
20 LSPI events per 100,000 combustion events.
DETAILED DESCRIPTION
[0028] Various preferred features and embodiments will be described
below by way of non-limiting illustration.
[0029] As indicated above, when operating the engine at speeds less
than or equal to 3,000 rpm and under a load with a break mean
effective pressure (BMEP) of greater than or equal to 10 bars, a
low-speed pre-ignition (LSPI) event may occur in the engine. A LSPI
event may consist of one or more LSPI combustion cycles, and
generally consists of multiple LSPI combustion cycles which occur
in a consecutive fashion or alternating fashion with normal
combustion cycles in between. Without being bound to a particular
theory, LSPI may result from a combustion of oil droplet(s), or a
droplet(s) of oil-fuel mixture, or combinations thereof, which may
accumulate, for example, in the top land crevices volume of a
piston, or the piston ring-land and ring-groove crevices. The
lubricant oil may be transferred from below the oil control ring to
the piston top land area due to unusual piston ring movements. At
low speed, high load conditions, in-cylinder pressures dynamics
(compression and firing pressures) may be considerably different
from in-cylinder pressures at lower loads, particularly due to
strongly retarded combustion phasing and high boost and peak
compression pressures which can influence ring motion dynamics.
[0030] At the foregoing loads, LSPI, which may be accompanied by
subsequent detonation and/or severe engine knock, can cause severe
damage to the engine very quickly (often within 1 to 5 engine
cycles). Engine knock may occur with LSPI given that, after the
normal spark from the igniter is provided, multiple flames may be
present. The present invention aims to provide a method for
inhibiting or reducing LSPI events, the method involving supplying
to the engine a lubricant comprising a metal overbased
detergent.
[0031] In one embodiment of the invention, the engine is operated
at speeds between 500 rpm and 3000 rpm, or 800 rpm to 2800 rpm, or
even 1000 rpm to 2600 rpm. Additionally, the engine may be operated
with a break mean effective pressure of 10 bars to 30 bars, or 12
bars to 24 bars.
[0032] LSPI events, while comparatively uncommon, may be
catastrophic in nature. Hence drastic reduction or even elimination
of LSPI events during normal or sustained operation of a direct
fuel injection engine is desirable. In one embodiment, the method
of the invention is such that there are less than 20 LSPI events
per 100,000 combustion events or less than 10 LSPI events per
100.000 combustion events. In one embodiment, there may be less
than 5 LSPI events per 100.000 combustion events, less than 3 LSPI
events per 100.000 combustion events; or there may be 0 LSPI events
per 100.000 combustion events.
[0033] In one embodiment, the method of the invention provides a
reduction in the number of LSPI events of at least 10 percent, or
at least 20 percent, or at least 30 percent, or at least 50
percent.
Fuel
[0034] The method of the present invention involves operating a
spark-ignited internal combustion engine. In addition to the engine
operating conditions and the lubricant composition, the composition
of the fuel may impact LSPI events. In one embodiment, the fuel may
comprise a fuel which is liquid at ambient temperature and is
useful in fueling a spark ignited engine, a fuel which is gaseous
at ambient temperatures, or combinations thereof.
[0035] The liquid fuel is normally a liquid at ambient conditions
e.g., room temperature (20 to 30.degree. C.). The fuel can be a
hydrocarbon fuel, a nonhydrocarbon fuel, or a mixture thereof. The
hydrocarbon fuel may be a gasoline as defined by ASTM specification
D4814. In an embodiment of the invention the fuel is a gasoline,
and in other embodiments the fuel is a leaded gasoline, or a
nonleaded gasoline.
[0036] The nonhydrocarbon fuel can be an oxygen containing
composition, often referred to as an oxygenate, to include an
alcohol, an ether, a ketone, an ester of a carboxylic acid, a
nitroalkane, or a mixture thereof. The nonhydrocarbon fuel can
include for example methanol, ethanol, methyl t-butyl ether, methyl
ethyl ketone, transesterified oils and/or fats from plants and
animals such as rapeseed methyl ester and soybean methyl ester, and
nitromethane. Mixtures of hydrocarbon and nonhydrocarbon fuels can
include, for example, gasoline and methanol and/or ethanol. In an
embodiment of the invention, the liquid fuel is a mixture of
gasoline and ethanol, wherein the ethanol content is at least 5
volume percent of the fuel composition, or at least 10 volume
percent of the composition, or at least 15 volume percent, or 15 to
85 volume percent of the composition. In one embodiment, the liquid
fuel contains less than 15% by volume ethanol content, less than
10% by volume ethanol content, less than 5% ethanol content by
volume, or is substantially free of (i.e. less than 0.5% by volume)
of ethanol.
[0037] In several embodiments of this invention, the fuel can have
a sulfur content on a weight basis that is 5000 ppm or less, 1000
ppm or less, 300 ppm or less, 200 ppm or less, 30 ppm or less, or
10 ppm or less. In another embodiment, the fuel can have a sulfur
content on a weight basis of 1 to 100 ppm. In one embodiment, the
fuel contains about 0 ppm to about 1000 ppm, about 0 to about 500
ppm, about 0 to about 100 ppm, about 0 to about 50 ppm, about 0 to
about 25 ppm, about 0 to about 10 ppm, or about 0 to 5 ppm of
alkali metals, alkaline earth metals, transition metals or mixtures
thereof. In another embodiment the fuel contains 1 to 10 ppm by
weight of alkali metals, alkaline earth metals, transition metals
or mixtures thereof.
[0038] The gaseous fuel is normally a gas at ambient conditions
e.g., room temperature (20 to 30.degree. C.). Suitable gas fuels
include natural gas, liquefied petroleum gas (LPG), compressed
natural gas (CNG), or mixtures thereof. In one embodiment, the
engine is fueled with natural gas.
[0039] The fuel compositions of the present invention can further
comprise one or more performance additives. Performance additives
can be added to a fuel composition depending on several factors,
including the type of internal combustion engine and the type of
fuel being used in that engine, the quality of the fuel, and the
service conditions under which the engine is being operated. In
some embodiments, the performance additives added are free of
nitrogen. In other embodiments, the additional performance
additives may contain nitrogen.
[0040] The performance additives can include an antioxidant such as
a hindered phenol or derivative thereof and/or a diarylamine or
derivative thereof; a corrosion inhibitor such as an
alkenylsuccinic acid; and/or a detergent/dispersant additive, such
as a polyetheramine or nitrogen containing detergent, including but
not limited to polyisobutylene (PIB) amine dispersants, Mannich
detergents, succinimide dispersants, and their respective
quaternary ammonium salts.
[0041] The performance additives may also include a cold flow
improver, such as an esterified copolymer of maleic anhydride and
styrene and/or a copolymer of ethylene and vinyl acetate; a foam
inhibitor, such as a silicone fluid; a demulsifier such as a
polyoxyalkylene and/or an alkyl polyether alcohol; a lubricity
agent such as a fatty carboxylic acid, ester and/or amide
derivatives of fatty carboxylic acids, or ester and/or amide
derivatives of hydrocarbyl substituted succinic anhydrides; a metal
deactivator, such as an aromatic triazole or derivative thereof,
including but not limited to a benzotriazole such as tolytriazole;
and/or a valve seat recession additive, such as an alkali metal
sulfosuccinate salt. The additives may also include a biocide, an
antistatic agent, a deicer, a fluidizer, such as a mineral oil
and/or a poly(alpha-olefin) and/or a polyether, and a combustion
improver, such as an octane or cetane improver.
[0042] The fluidizer may be a polyetheramine or a polyether
compound. The polyetheramine can be represented by the formula
R[--OCH.sub.2CH(R.sup.1)].sub.nA, where R is a hydrocarbyl group,
R.sup.1 is selected from the group consisting of hydrogen,
hydrocarbyl groups of 1 to 16 carbon atoms, and mixtures thereof, n
is a number from 2 to about 50, and A is selected from the group
consisting of --OCH.sub.2CH.sub.2CH.sub.2NR.sup.2R.sup.2 and
--NR.sup.3R.sup.3, where each R.sup.2 is independently hydrogen or
hydrocarbyl, and each R.sup.3 is independently hydrogen,
hydrocarbyl or --[R.sup.4N(R.sup.5)].sub.pR.sup.6, where R.sup.4 is
C.sub.2-C.sub.10 alkylene, R.sup.5 and R.sup.6 are independently
hydrogen or hydrocarbyl, and p is a number from 1-7.
[0043] The fluidizer can be a polyether, which can be represented
by the formula R.sup.7O[CH.sub.2CH(R.sup.8)O].sub.qH, where R.sup.7
is a hydrocarbyl group, R.sup.8 is selected from the group
consisting of hydrogen, hydrocarbyl groups of 1 to 16 carbon atoms,
and mixtures thereof, and q is a number from 2 to about 50. The
fluidizer can be a hydrocarbyl-terminated poly-(oxyalklene)
aminocarbamate as described U.S. Pat. No. 5,503,644. The fluidizer
can be an alkoxylate, wherein the alkoxylate can comprise: (i) a
polyether containing two or more ester terminal groups; (ii) a
polyether containing one or more ester groups and one or more
terminal ether groups; or (iii) a polyether containing one or more
ester groups and one or more terminal amino groups, wherein a
terminal group is defined as a group located within five connecting
carbon or oxygen atoms from the end of the polymer. Connecting is
defined as the sum of the connecting carbon and oxygen atoms in the
polymer or end group.
[0044] The performance additives which may be present in the fuel
additive compositions and fuel compositions of the present
invention also include di-ester, di-amide, ester-amide, and
ester-imide friction modifiers prepared by reacting a dicarboxylic
acid (such as tartaric acid) and/or a tricarboxylic acid (such as
citric acid), with an amine and/or alcohol, optionally in the
presence of a known esterification catalyst. These friction
modifiers often derived from tartaric acid, citric acid, or
derivatives thereof, may be derived from amines and/or alcohols
that are branched so that the friction modifier itself has
significant amounts of branched hydrocarbyl groups present within
it structure. Examples of suitable branched alcohols used to
prepare these friction modifiers include 2-ethylhexanol,
isotridecanol, Guerbet alcohols, or mixtures thereof.
[0045] In different embodiments the fuel composition may have a
composition as described in the following table:
TABLE-US-00001 Embodiments (ppm) Additive A C D
Detergent/dispersant 0 to 2500 25 to 150 500 to 2500 Fluidizer 0 to
5000 1 to 250 3000 to 5000 Demulsifier 0 to 50 0.5 to 5 1 to 25
Corrosion Inhibitor 0 to 200 .5 to 10 20 to 200 Antioxidant 0 to
1000 5 to 125 500 to 1000 Friction Modifier 0 to 600 50 to 175 100
to 750 Fuel Balance Balance Balance to 100% to 100% to 100%
Oil of Lubricating Viscosity
[0046] The lubricating composition comprises an oil of lubricating
viscosity. Such oils include natural and synthetic oils, oil
derived from hydrocracking, hydrogenation, and hydrofinishing,
unrefined, refined, re-refined oils or mixtures thereof. A more
detailed description of unrefined, refined and re-refined oils is
provided in International Publication WO2008/147704, paragraphs
[0054] to [0056] (a similar disclosure is provided in US Patent
Publication 2010/0197536, see [0072] to [0073]). A more detailed
description of natural and synthetic lubricating oils is described
in paragraphs [0058] to [0059] respectively of WO2008/147704 (a
similar disclosure is provided in US Patent Publication
2010/0197536, see [0075] to [0076]). Synthetic oils may also be
produced by Fischer-Tropsch reactions and typically may be
hydroisomerised Fischer-Tropsch hydrocarbons or waxes. In one
embodiment, oils may be prepared by a Fischer-Tropsch gas-to-liquid
synthetic procedure as well as other gas-to-liquid oils.
[0047] Oils of lubricating viscosity may also be defined as
specified in the April 2008 version of "Appendix E--API Base Oil
Interchangeability Guidelines for Passenger Car Motor Oils and
Diesel Engine Oils", section 1.3 Sub-heading 1.3. "Base Stock
Categories". The API Guidelines are also summarized in U.S. Pat.
No. 7,285,516 (see column 11, line 64 to column 12, line 10). In
one embodiment, the oil of lubricating viscosity may be an API
Group II, Group III, or Group IV oil, or mixtures thereof. The five
base oil groups are as follows:
TABLE-US-00002 Base Oil Category Sulfur (%) Saturates (%) Viscosity
Index Group I .sup. >0.03 and/or <90 80 to 120 Group II
.ltoreq.0.03 and .gtoreq.90 80 to 120 Group III .ltoreq.0.03 and
.gtoreq.90 .gtoreq.120 Group IV All polyalphaolefins (PAO) Group V
All others not included in Groups I, II, III, or IV
[0048] The amount of the oil of lubricating viscosity present is
typically the balance remaining after subtracting from 100 weight %
(wt %) the sum of the amount of the compound of the invention and
the other performance additives.
[0049] The lubricating composition may be in the form of a
concentrate and/or a fully formulated lubricant. If the lubricating
composition of the invention (comprising the additives disclosed
herein) is in the form of a concentrate which may be combined with
additional oil to form, in whole or in part, a finished lubricant),
the ratio of the of these additives to the oil of lubricating
viscosity and/or to diluent oil include the ranges of 1:99 to 99:1
by weight, or 80:20 to 10:90 by weight.
[0050] In one embodiment, the base oil has a kinematic viscosity at
100.degree. C. from 2 mm.sup.2/s (centiStokes-cSt) to 16
mm.sup.2/s, from 3 mm.sup.2/s to 10 mm.sup.2/s, or even from 4
mm.sup.2/s to 8 mm.sup.2/s.
[0051] The ability of a base oil to act as a solvent (i.e.
solvency) may be a contributing factor in increasing the frequency
of LSPI events during operation of a direct fuel-injected engine.
Base oil solvency may be measured as the ability of an un-additized
base oil to act as a solvent for polar constituents. In general,
base oil solvency decreases as the base oil group moves from Group
I to Group IV (PAO). That is, solvency of base oil may be ranked as
follows for oil of a given kinematic viscosity: Group I>Group
II>Group III>Group IV. Base oil solvency also decreases as
the viscosity increases within a base oil group; base oil of low
viscosity tends to have better solvency than similar base oil of
higher viscosity. Base oil solvency may be measured by aniline
point (ASTM D611).
[0052] In one embodiment, the base oil comprises at least 30 wt %
of Group II or Group III base oil. In another embodiment, the base
oil comprises at least 60 weight % of Group II or Group III base
oil, or at least 80 wt % of Group II or Group III base oil. In one
embodiment, the lubricant composition comprises less than 20 wt %
of Group IV (i.e. polyalphaolefin) base oil. In another embodiment,
the base oil comprises less than 10 wt % of Group IV base oil. In
one embodiment, the lubricating composition is substantially free
of (i.e. contains less than 0.5 wt %) of Group IV base oil.
[0053] Ester base fluids, which are characterized as Group V oils,
have high levels of solvency as a result of their polar nature.
Addition of low levels (typically less than 10 wt %) of ester to a
lubricating composition may significantly increase the resulting
solvency of the base oil mixture. Esters may be broadly grouped
into two categories: synthetic and natural. An ester base fluid
would have a kinematic viscosity at 100.degree. C. suitable for use
in an engine oil lubricant, such as between 2 cSt and 30 cSt, or
from 3 cSt to 20 cSt, or even from 4 cSt to 12 cSt.
[0054] Synthetic esters may comprise esters of dicarboxylic acids
(e.g., phthalic acid, succinic acid, alkyl succinic acids and
alkenyl succinic acids, maleic acid, azelaic acid, suberic acid,
sebacic acid, fumaric acid, adipic acid, linoleic acid dimer,
malonic acid, alkyl malonic acids, and alkenyl malonic acids) with
any of variety of monohydric alcohols (e.g., butyl alcohol, hexyl
alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol,
diethylene glycol monoether, and propylene glycol). Specific
examples of these esters include dibutyl adipate, di(2-ethylhexyl)
sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl
azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate,
dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid
dimer, and the complex ester formed by reacting one mole of sebacic
acid with two moles of tetraethylene glycol and two moles of
2-ethylhexanoic acid. Other synthetic esters include those made
from C5 to C12 monocarboxylic acids and polyols and polyol ethers
such as neopentyl glycol, trimethylolpropane, pentaerythritol,
dipentaerythritol, and tripentaerythritol. Esters can also be
monoesters of mono-carboxylic acids and monohydric alcohols.
[0055] Natural (or bio-derived) esters refer to materials derived
from a renewable biological resource, organism, or entity, distinct
from materials derived from petroleum or equivalent raw materials.
Natural esters include fatty acid triglycerides, hydrolyzed or
partially hydrolyzed triglycerides, or transesterified triglyceride
esters, such as fatty acid methyl ester (or FAME). Suitable
triglycerides include, but are not limited to, palm oil, soybean
oil, sunflower oil, rapeseed oil, olive oil, linseed oil, and
related materials. Other sources of triglycerides include, but are
not limited to, algae, animal tallow, and zooplankton. Methods for
producing biolubricants from natural triglycerides are described
in, e.g., United States Patent Publication 2011/0009300A1.
[0056] In one embodiment, the lubricating composition comprises at
least 2 wt % of an ester base fluid. In one embodiment the
lubricating composition of the invention comprises at least 4 wt %
of an ester base fluid, or at least 7 wt % of an ester base fluid,
or even at least 10 wt % of an ester base fluid.
Metal Overbased Detergent
[0057] Metal overbased detergents, otherwise referred to as
overbased detergents, metal-containing overbased detergents or
superbased salts, are characterized by a metal content in excess of
that which would be necessary for neutralization according to the
stoichiometry of the metal and the particular acidic organic
compound, i.e. the substrate, reacted with the metal. The overbased
detergent may comprise one or more of non-sulfur containing
phenates, sulfur containing phenates, sulfonates, salicylates, and
mixtures thereof.
[0058] The amount of excess metal is commonly expressed in terms of
substrate to metal ratio. The terminology "metal ratio" is used in
the prior art and herein to define the ratio of the total chemical
equivalents of the metal in the overbased salt to the chemical
equivalents of the metal in the salt which would be expected to
result from the reaction between the hydrocarbyl substituted
organic acid; the hydrocarbyl-substituted phenol or mixtures
thereof to be overbased, and the basic metal compound according to
the known chemical reactivity and the stoichiometry of the two
reactants. Thus, in a normal or neutral salt (i.e. soap) the metal
ratio is one and, in an overbased salt, the metal ratio is greater
than one, especially greater than 1.3. The overbased detergent of
the invention may have a metal ratio of 5 to 30, or a metal ratio
of 7 to 22, or a metal ratio of at least 11.
[0059] The metal-containing detergent may also include "hybrid"
detergents formed with mixed surfactant systems including phenate
and/or sulfonate components, e.g. phenate-salicylates,
sulfonate-phenates, sulfonate-salicylates,
sulfonates-phenates-salicylates, as described, for example, in U.S.
Pat. Nos. 6,429,178; 6,429,179; 6,153,565; and 6,281,179. Where,
for example, a hybrid sulfonate/phenate detergent is employed, the
hybrid detergent would be considered equivalent to amounts of
distinct phenate and sulfonate detergents introducing like amounts
of phenate and sulfonate soaps, respectively. Overbased phenates
and salicylates typically have a total base number of 180 to 450
TBN. Overbased sulfonates typically have a total base number of 250
to 600, or 300 to 500. Overbased detergents are known in the
art.
[0060] Alkylphenols are often used as constituents in and/or
building blocks for overbased detergents. Alkylphenols may be used
to prepare phenate, salicylate, salixarate, or saligenin detergents
or mixtures thereof. Suitable alkylphenols may include
para-substituted hydrocarbyl phenols. The hydrocarbyl group may be
linear or branched aliphatic groups of 1 to 60 carbon atoms, 8 to
40 carbon atoms, 10 to 24 carbon atoms, 12 to 20 carbon atoms, or
16 to 24 carbon atoms. In one embodiment, the alkylphenol overbased
detergent is prepared from an alkylphenol or mixture thereof that
is free of or substantially free of (i.e. contains less than 0.1
weight percent) p-dodecylphenol. In one embodiment, the lubricating
composition of the invention contains less than 0.3 weight percent
of alkylphenol, less than 0.1 weight percent of alkylphenol, or
less than 0.05 weight percent of alkylphenol.
[0061] The overbased metal-containing detergent may be alkali metal
or alkaline earth metal salts. In one embodiment, the overbased
detergent may be sodium salts, calcium salts, magnesium salts, or
mixtures thereof of the phenates, sulfur-containing phenates,
sulfonates, salixarates and salicylates. In one embodiment, the
overbased detergent is a calcium detergent, a magnesium detergent
or mixtures thereof. In one embodiment, the overbased calcium
detergent may be present in an amount to deliver at least 500 ppm
calcium by weight and no more than 3000 ppm calcium by weight, or
at least 1000 ppm calcium by weight, or at least 2000 ppm calcium
by weight, or no more than 2500 ppm calcium by weight to the
lubricating composition. In one embodiment, the overbased detergent
may be present in an amount to deliver no more than 500 ppm by
weight of magnesium to the lubricating composition, or no more than
330 ppm by weight, or no more than 125 ppm by weight, or no more
than 45 ppm by weight. In one embodiment, the lubricating
composition is essentially free of (i.e. contains less than 10 ppm)
magnesium resulting from the overbased detergent. In one
embodiment, the overbased detergent may be present in an amount to
deliver at least 200 ppm by weight of magnesium, or at least 450
ppm by weight magnesium, or at least 700 ppm by weight magnesium to
the lubricating composition. In one embodiment, both calcium and
magnesium containing detergents may be present in the lubricating
composition. Calcium and magnesium detergents may be present such
that the weight ratio of calcium to magnesium is 10:1 to 1:10, or
8:3 to 4:5, or 1:1 to 1:3. In one embodiment, the overbased
detergent is free of or substantially free of sodium.
[0062] In one embodiment, the sulfonate detergent may be
predominantly a linear alkylbenzene sulfonate detergent having a
metal ratio of at least 8 as is described in paragraphs [0026] to
[0037] of US Patent Publication 2005/065045 (and granted as U.S.
Pat. No. 7,407,919). The linear alkylbenzene sulfonate detergent
may be particularly useful for assisting in improving fuel economy.
The linear alkyl group may be attached to the benzene ring anywhere
along the linear chain of the alkyl group, but often in the 2, 3 or
4 position of the linear chain, and in some instances,
predominantly in the 2 position, resulting in the linear
alkylbenzene sulfonate detergent.
[0063] Salicylate detergents and overbased salicylate detergents
may be prepared in at least two different manners. Carbonylation
(also referred to as carboxylation) of a p-alkylphenol is described
in many references including U.S. Pat. No. 8,399,388. Carbonylation
may be followed by overbasing to form overbased salicylate
detergent. Suitable p-alkylphenols include those with linear and/or
branched hydrocarbyl groups of 1 to 60 carbon atoms. Salicylate
detergents may also be prepared by alkylation of salicylic acid,
followed by overbasing, as described in U.S. Pat. No. 7,009,072.
Salicylate detergents prepared in this manner, may be prepared from
linear and/or branched alkylating agents (usually 1-olefins)
containing 6 to 50 carbon atoms, 10 to 30 carbon atoms, or 14 to 24
carbon atoms. In one embodiment, the overbased detergent of the
invention is a salicylate detergent. In one embodiment, the
salicylate detergent of the invention is free of unreacted
p-alkylphenol (i.e. contains less than 0.1 weight percent). In one
embodiment, the salicylate detergent of the invention is prepared
by alkylation of salicylic acid.
[0064] The overbased detergent may be present at 0.2 wt % to 15 wt
%, or 0.3 wt % to 10 wt %, or 0.3 wt % to 8 wt %, or 0.4 wt % to 3
wt %. For example, in a heavy duty diesel engine, the detergent may
be present at 2 wt % to 3 wt % of the lubricating composition. For
a passenger car engine, the detergent may be present at 0.2 wt % to
1 wt % of the lubricating composition.
[0065] Metal-containing detergents contribute sulfated ash to a
lubricating composition. Sulfated ash may be determined by ASTM
D874. In one embodiment, the lubricating composition of the
invention comprises a metal-containing detergent in an amount to
deliver at least 0.4 weight percent sulfated ash to the total
composition. In another embodiment, the metal-containing detergent
is present in an amount to deliver at least 0.6 weight percent
sulfated ash, or at least 0.75 weight percent sulfated ash, or even
at least 0.9 weight percent sulfated ash to the lubricating
composition. In one embodiment, the metal-containing overbased
detergent is present in an amount to deliver 0.1 weight percent to
0.8 weight percent sulfated ash to the lubricating composition.
[0066] In addition to ash and TBN, overbased detergents contribute
detergent soap, also referred to as neutral detergent salt, to the
lubricating composition. Soap, being a metal salt of the substrate,
may act as a surfactant in the lubricating composition. In one
embodiment, the lubricating composition comprises 0.05 weight
percent to 1.5 weight percent detergent soap, or 0.1 weight percent
to 0.9 weight percent detergent soap. In one embodiment, the
lubricating composition contains no more than 0.5 weight percent
detergent soap. The overbased detergent may have a weight ratio of
ash:soap of 5:1 to 1:2.3, or 3.5:1 to 1:2, or 2.9:1 to 1:1:7.
Other Performance Additives
[0067] The compositions of the invention may optionally comprise
one or more additional performance additives. These additional
performance additives may include one or more metal deactivators,
viscosity modifiers, antioxidants, friction modifiers, antiwear
agents, corrosion inhibitors, dispersants, dispersant viscosity
modifiers, extreme pressure agents, antioxidants (other than those
of the invention), foam inhibitors, demulsifiers, pour point
depressants, seal swelling agents, and any combination or mixture
thereof. Typically, fully-formulated lubricating oil will contain
one or more of these performance additives, and often a package of
multiple performance additives
[0068] In one embodiment, the invention provides a lubricating
composition further comprising a dispersant, an antiwear agent, a
dispersant viscosity modifier, a friction modifier, a viscosity
modifier, an antioxidant, a detergent (different from that of the
invention) or a combination thereof, where each of the additives
listed may be a mixture of two or more of that type of additive. In
one embodiment, the invention provides a lubricating composition
further comprising a polyisobutylene succinimide dispersant, an
antiwear agent, a dispersant viscosity modifier, a friction
modifier, a viscosity modifier (typically an olefin copolymer such
as an ethylene-propylene copolymer), an antioxidant (including
phenolic and aminic antioxidants), an overbased detergent
(including overbased sulfonates and phenates), or a combination
thereof, where each of the additives listed may be a mixture of two
or more of that type of additive.
[0069] In one embodiment, the invention provides a lubricating
composition which further comprises ashless antioxidant. Ashless
antioxidants may comprise one or more of arylamines, diarylamines,
alkylated arylamines, alkylated diaryl amines, phenols, hindered
phenols, sulfurized olefins, or mixtures thereof. In one embodiment
the lubricating composition includes an antioxidant, or mixtures
thereof. The antioxidant may be present at 0 wt % to 15 wt %, or
0.1 wt % to 10 wt %, or 0.5 wt % to 5 wt %, or 0.5 wt % to 3 wt %,
or 0.3 wt % to 1.5 wt % of the lubricating composition.
[0070] The diarylamine or alkylated diarylamine may be a
phenyl-.alpha.-naphthylamine (PANA), an alkylated diphenylamine, or
an alkylated phenylnapthylamine, or mixtures thereof. The alkylated
diphenylamine may include di-nonylated diphenylamine, nonyl
diphenylamine, octyl diphenylamine, di-octylated diphenylamine,
di-decylated diphenylamine, decyl diphenylamine and mixtures
thereof. In one embodiment, the diphenylamine may include nonyl
diphenylamine, dinonyl diphenylamine, octyl diphenylamine, dioctyl
diphenylamine, or mixtures thereof. In one embodiment the alkylated
diphenylamine may include nonyl diphenylamine, or dinonyl
diphenylamine. The alkylated diarylamine may include octyl,
di-octyl, nonyl, di-nonyl, decyl or di-decyl
phenylnapthylamines.
[0071] The diarylamine antioxidant of the invention may be present
on a weight basis of this lubrication composition at 0.1% to 10%,
0.35% to 5%, or even 0.5% to 2%.
[0072] The phenolic antioxidant may be a simple alkyl phenol, a
hindered phenol, or coupled phenolic compounds.
[0073] The hindered phenol antioxidant often contains a secondary
butyl and/or a tertiary butyl group as a sterically hindering
group. The phenol group may be further substituted with a
hydrocarbyl group (typically linear or branched alkyl) and/or a
bridging group linking to a second aromatic group. Examples of
suitable hindered phenol antioxidants include
2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol,
4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol
or 4-butyl-2,6-di-tert-butylphenol,
4-dodecyl-2,6-di-tert-butylphenol, or butyl
3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate. In one embodiment,
the hindered phenol antioxidant may be an ester and may include,
e.g., Irganox.TM. L-135 from Ciba.
[0074] Coupled phenols often contain two alkylphenols coupled with
alkylene groups to form bisphenol compounds. Examples of suitable
coupled phenol compounds include 4,4'-methylene
bis-(2,6-di-tert-butyl phenol), 4-methyl-2,6-di-tert-butylphenol,
2,2'-bis-(6-t-butyl-4-heptylphenol); 4,4'-bis(2,6-di-t-butyl
phenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), and
2,2'-methylene bis(4-ethyl-6-t-butylphenol).
[0075] Phenols of the invention also include polyhydric aromatic
compounds and their derivatives. Examples of suitable polyhydric
aromatic compounds include esters and amides of gallic acid,
2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid,
1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxynaphthoic acid,
3,7-dihydroxy naphthoic acid, and mixtures thereof.
[0076] In one embodiment, the phenolic antioxidant comprises a
hindered phenol. In another embodiment the hindered phenol is
derived from 2,6-ditertbutyl phenol.
[0077] In one embodiment the lubricating composition of the
invention comprises a phenolic antioxidant in a range of 0.01 wt %
to 5 wt %, or 0.1 wt % to 4 wt %, or 0.2 wt % to 3 wt %, or 0.5 wt
% to 2 wt % of the lubricating composition.
[0078] Sulfurized olefins are well known commercial materials, and
those which are substantially nitrogen-free, that is, not
containing nitrogen functionality, are readily available. The
olefinic compounds which may be sulfurized are diverse in nature.
They contain at least one olefinic double bond, which is defined as
a non-aromatic double bond; that is, one connecting two aliphatic
carbon atoms. These materials generally have sulfide linkages
having 1 to 10 sulfur atoms, for instance, 1 to 4, or 1 or 2.
[0079] Ashless antioxidants may be used separately or in
combination. In one embodiment of the invention, two or more
different antioxidants are used in combination, such that there is
at least 0.1 weight percent of each of the at least two
antioxidants and wherein the combined amount of the ashless
antioxidants is 0.5 to 5 weight percent. In one embodiment, there
may be at least 0.25 to 3 weight percent of each ashless
antioxidant.
[0080] In one embodiment, the invention provides a lubricating
composition further comprising a molybdenum compound. The
molybdenum compound may be selected from the group consisting of
molybdenum dialkyldithiophosphates, molybdenum dithiocarbamates,
amine salts of molybdenum compounds, and mixtures thereof. The
molybdenum compound may provide the lubricating composition with 0
to 1000 ppm, or 5 to 1000 ppm, or 10 to 750 ppm, or 5 ppm to 300
ppm, or 20 ppm to 250 ppm of molybdenum.
[0081] Suitable dispersants for use in the compositions of the
present invention include succinimide dispersants. In one
embodiment, the dispersant may be present as a single dispersant.
In one embodiment, the dispersant may be present as a mixture of
two or three different dispersants, wherein at least one may be a
succinimide dispersant.
[0082] The succinimide dispersant may be a derivative of an
aliphatic polyamine, or mixtures thereof. The aliphatic polyamine
may be aliphatic polyamine such as an ethylenepolyamine, a
propylenepolyamine, a butylenepolyamine, or mixtures thereof. In
one embodiment, the aliphatic polyamine may be ethylenepolyamine.
In one embodiment, the aliphatic polyamine may be selected from the
group consisting of ethylenediamine, diethylenetriamine,
triethylenetetramine, tetraethylenepentamine,
pentaethylenehexamine, polyamine still bottoms, and mixtures
thereof.
[0083] The dispersant may be a N-substituted long chain alkenyl
succinimide. Examples of N-substituted long chain alkenyl
succinimide include polyisobutylene succinimide. Typically the
polyisobutylene from which polyisobutylene succinic anhydride is
derived has a number average molecular weight of 350 to 5000, or
550 to 3000 or 750 to 2500. Succinimide dispersants and their
preparation are disclosed, for instance in U.S. Pat. Nos.
3,172,892, 3,219,666, 3,316,177, 3,340,281, 3,351,552, 3,381,022,
3,433,744, 3,444,170, 3,467,668, 3,501,405, 3,542,680, 3,576,743,
3,632,511, 4,234,435, Re 26,433, and U.S. Pat. Nos. 6,165,235,
7,238,650 and EP Patent 0 355 895B1.
[0084] The dispersant may also be post-treated by conventional
methods by a reaction with any of a variety of agents. Among these
are boron compounds, urea, thiourea, dimercaptothiadiazoles, carbon
disulfide, aldehydes, ketones, carboxylic acids,
hydrocarbon-substituted succinic anhydrides, maleic anhydride,
nitriles, epoxides, and phosphorus compounds.
[0085] The dispersant may be present at 0.01 wt % to 20 wt %, or
0.1 wt % to 15 wt %, or 0.1 wt % to 10 wt %, or 1 wt % to 6 wt % of
the lubricating composition.
[0086] In one embodiment, the lubricating composition of the
invention further comprises a dispersant viscosity modifier. The
dispersant viscosity modifier may be present at 0 wt % to 5 wt %,
or 0 wt % to 4 wt %, or 0.05 wt % to 2 wt % of the lubricating
composition.
[0087] Suitable dispersant viscosity modifiers include
functionalized polyolefins, for example, ethylene-propylene
copolymers that have been functionalized with an acylating agent
such as maleic anhydride and an amine; polymethacrylates
functionalized with an amine, or esterified styrene-maleic
anhydride copolymers reacted with an amine. More detailed
description of dispersant viscosity modifiers are disclosed in
International Publication WO2006/015130 or U.S. Pat. Nos.
4,863,623; 6,107,257; 6,107,258; and 6,117,825. In one embodiment,
the dispersant viscosity modifier may include those described in
U.S. Pat. No. 4,863,623 (see column 2, line 15 to column 3, line
52) or in International Publication WO2006/015130 (see page 2,
paragraph [0008] and preparative examples are described at
paragraphs [0065] to [0073]).
[0088] In one embodiment, the invention provides a lubricating
composition which further includes a phosphorus-containing antiwear
agent. Typically, the phosphorus-containing antiwear agent may be a
zinc dialkyldithiophosphate. Zinc dialkyldithiophosphates are known
in the art. The antiwear agent may be present at 0 wt % to 3 wt %,
or 0.1 wt % to 1.5 wt %, or 0.5 wt % to 0.9 wt % of the lubricating
composition.
[0089] In one embodiment, the invention provides a lubricating
composition further comprising a friction modifier. Examples of
friction modifiers include long chain fatty acid derivatives of
amines, fatty esters, or epoxides; fatty imidazolines such as
condensation products of carboxylic acids and
polyalkylene-polyamines; amine salts of alkylphosphoric acids;
fatty alkyl tartrates; fatty alkyl tartrimides; or fatty alkyl
tartramides. The term fatty, as used herein, can mean having a
C8-22 linear alkyl group.
[0090] Friction modifiers may also encompass materials such as
sulfurized fatty compounds and olefins, molybdenum
dialkyldithiophosphates, molybdenum dithiocarbamates, sunflower oil
or monoester of a polyol and an aliphatic carboxylic acid.
[0091] In one embodiment, the friction modifier may be selected
from the group consisting of long chain fatty acid derivatives of
amines, long chain fatty esters, or long chain fatty epoxides;
fatty imidazolines; amine salts of alkylphosphoric acids; fatty
alkyl tartrates; fatty alkyl tartrimides; and fatty alkyl
tartramides. The friction modifier may be present at 0 wt % to 6 wt
%, or 0.05 wt % to 4 wt %, or 0.1 wt % to 2 wt % of the lubricating
composition.
[0092] In one embodiment, the friction modifier may be a long chain
fatty acid ester. In another embodiment the long chain fatty acid
ester may be a mono-ester or a diester or a mixture thereof, and in
another embodiment, the long chain fatty acid ester may be a
triglyceride.
[0093] Other performance additives such as corrosion inhibitors
include those described in paragraphs 5 to 8 of U.S. application
Ser. No. 05/038,319, published as WO2006/047486, octyl octanamide,
condensation products of dodecenyl succinic acid or anhydride and a
fatty acid such as oleic acid with a polyamine. In one embodiment,
the corrosion inhibitors include the Synalox.RTM. (a registered
trademark of The Dow Chemical Company) corrosion inhibitor. The
Synalox.RTM. corrosion inhibitor may be a homopolymer or copolymer
of propylene oxide. The Synalox.RTM. corrosion inhibitor is
described in more detail in a product brochure with Form No.
118-01453-0702 AMS, published by The Dow Chemical Company. The
product brochure is entitled "SYNALOX Lubricants, High-Performance
Polyglycols for Demanding Applications."
[0094] The lubricating composition may further include metal
deactivators, including derivatives of benzotriazoles (typically
tolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazoles,
benzimidazoles, 2-alkyldithiobenzimidazoles, or
2-alkyldithiobenzothiazoles; foam inhibitors, including copolymers
of ethyl acrylate and 2-ethylhexylacrylate and copolymers of ethyl
acrylate and 2-ethylhexylacrylate and vinyl acetate; demulsifiers
including trialkyl phosphates, polyethylene glycols, polyethylene
oxides, polypropylene oxides and (ethylene oxide-propylene oxide)
polymers; and pour point depressants, including esters of maleic
anhydride-styrene, polymethacrylates, polyacrylates or
polyacrylamides.
[0095] Pour point depressants that may be useful in the
compositions of the invention further include polyalphaolefins,
esters of maleic anhydride-styrene, poly(meth)acrylates,
polyacrylates or polyacrylamides.
[0096] In different embodiments, the lubricating composition may
have a composition as described in the following table:
TABLE-US-00003 Embodiments (wt %) Additive A B C Antioxidant of
Invention 0.05 to 1 0.2 to 3 0.5 to 2 Dispersant 0.05 to 12 0.75 to
8 0.5 to 6 Dispersant Viscosity Modifier 0 or 0 or 0.05 to 2 0.05
to 5 0.05 to 4 Overbased Detergent 0 or 0.1 to 10 0.2 to 8 0.05 to
15 Additional Antioxidant 0 or 0.1 to 10 0.5 to 5 0.05 to 15
Antiwear Agent 0 or 0.1 to 10 0.3 to 5 0.05 to 15 Friction Modifier
0 or 0.05 to 4 0.1 to 2 0.05 to 6 Viscosity Modifier 0 or 0.5 to 8
1 to 6 0.05 to 10 Any Other Performance Additive 0 or 0 or 0 or
0.05 to 10 0.05 to 8 0.05 to 6 Oil of Lubricating Viscosity Balance
to Balance to Balance to 100% 100% 100%
[0097] The present invention provides a surprising ability to
prevent damage to an engine in operation due to pre-ignition events
resulting from direct gasoline injection into the combustion
chamber. This is accomplished while maintaining fuel economy
performance, low sulfated ash levels, improved deposit control, and
other limitations, required by increasingly stringent government
regulations.
INDUSTRIAL APPLICATION
[0098] As described above, the invention provides for a method of
lubricating an internal combustion engine comprising supplying to
the internal combustion engine a lubricating composition as
disclosed herein. Generally, the lubricant is added to the
lubricating system of the internal combustion engine, which then
delivers the lubricating composition to the critical parts of the
engine, during its operation, that require lubrication
[0099] The lubricating compositions described above may be utilized
in an internal combustion engine. The engine components may have a
surface of steel or aluminum (typically a surface of steel) and may
also be coated for example with a diamondlike carbon (DLC)
coating.
[0100] An aluminum surface may be comprised of an aluminum alloy
that may be a eutectic or hyper-eutectic aluminum alloy (such as
those derived from aluminum silicates, aluminum oxides, or other
ceramic materials). The aluminum surface may be present on a
cylinder bore, cylinder block, or piston ring having an aluminum
alloy, or aluminum composite.
[0101] The internal combustion engine may be fitted with an
emission control system or a turbocharger. Examples of the emission
control system include diesel particulate filters (DPF), or systems
employing selective catalytic reduction (SCR).
[0102] The internal combustion engine of the present invention is
distinct from a gas turbine. In an internal combustion engine,
individual combustion events translate from a linear reciprocating
force into a rotational torque through the rod and crankshaft. In
contrast, in a gas turbine (which may also be referred to as a jet
engine) a continuous combustion process generates a rotational
torque continuously without translation and can also develop thrust
at the exhaust outlet. These differences in operation conditions of
a gas turbine and internal combustion engine result in different
operating environments and stresses.
[0103] The lubricant composition for an internal combustion engine
may be suitable for any engine lubricant irrespective of the
sulfur, phosphorus or sulfated ash (ASTM D-874) content. The sulfur
content of the engine oil lubricant may be 1 wt % or less, or 0.8
wt % or less, or 0.5 wt % or less, or 0.3 wt % or less. In one
embodiment, the sulfur content may be in the range of 0.001 wt % to
0.5 wt %, or 0.01 wt % to 0.3 wt %. The phosphorus content may be
0.2 wt % or less, or 0.12 wt % or less, or 0.1 wt % or less, or
0.085 wt % or less, or 0.08 wt % or less, or even 0.06 wt % or
less, 0.055 wt % or less, or 0.05 wt % or less. In one embodiment
the phosphorus content may be 100 ppm to 1000 ppm, or 200 ppm to
600 ppm. The total sulfated ash content may be 2 wt % or less, or
1.5 wt % or less, or 1.1 wt % or less, or 1 wt % or less, or 0.8 wt
% or less, or 0.5 wt % or less, or 0.4 wt % or less. In one
embodiment, the sulfated ash content may be 0.05 wt % to 0.9 wt %,
or 0.1 wt % to 0.2 wt % or to 0.45 wt %.
[0104] In one embodiment, the lubricating composition may be an
engine oil, wherein the lubricating composition may be
characterized as having at least one of (i) a sulfur content of 0.5
wt % or less, (ii) a phosphorus content of 0.1 wt % or less, (iii)
a sulfated ash content of 1.5 wt % or less, or combinations
thereof.
EXAMPLES
[0105] The invention will be further illustrated by the following
examples, which set forth particularly advantageous embodiments.
While the examples are provided to illustrate the invention, they
are not intended to limit it.
Lubricating Compositions
[0106] A series of 5W-20 engine lubricants in Group II base oil of
lubricating viscosity are prepared containing the additives
described above as well as conventional additives including
polymeric viscosity modifier, ashless succinimide dispersant,
overbased detergents, antioxidants (combination of phenolic ester
and diarylamine), zinc dialkyldithiophosphate (ZDDP), as well as
other performance additives as follows (Table 1). The phosphorus,
sulfur and ash contents of each of the examples are also presented
in the table in part to show that each example has a similar amount
of these materials and so provide a proper comparison between the
comparative and invention examples.
TABLE-US-00004 TABLE 1 Lubricating Oil Composition
Formulations.sup.1 COMP INV INV INV INV INV EX1 EX2 EX3 EX4 EX5 EX6
Group III Base Oil Balance to = 100% Ca Sulfonate 1.sup.2 0 0.26
1.13 0 0.76 0.51 Ca Sulfonate 2.sup.3 0 0.12 0 0.06 0.35 Ca
Sulfonate 3.sup.4 1.0 0 0 0 0 0 Ca Phenate.sup.5 0 0 0 1.4 0 0 Na
Sulfonate.sup.6 0.18 0.09 0 0 0.26 0.18 Mg Sulfonate.sup.7 0 0 0 0
0 0 Ashless 1.4 0.725 1.4 2.0 2.18 4.0 Antioxidant.sup.8
Dispersant.sup.9 2.5 1.2 2.0 4.6 3.6 2.4 ZDDP 0.76 0.4 0.7 0.45 1.1
0.76 VI Improver 1.0 1.0 2.1 1.1 1.0 0.55 Additional 1.0 0.85 1.4
0.58 2.1 2.0 Additives.sup.10 % Phosphorus 0.076 0.038 0.060 0.046
0.11 0.076 % Calcium 0.168 0.084 0.234 0.123 0.251 0.168 % Sodium
0.049 0.024 0 0 0.073 0.049 % Molybdenum 0 46 0 0 140 90 (ppm) TB N
10.8 3.84 7.75 6.1 11.5 10.8 % Ash 0.9 0.44 0.9 0.50 1.31 0.88
.sup.1All amounts shown above are in weight percent and are on an
oil-free basis unless otherwise noted. .sup.2Ca Sulfonate 1:
Overbased calcium sulfonate with oil free TBN of 520; metal ratio
of 10 .sup.3Ca Sulfonate 2: Overbased calcium sulfonate with oil
free TBN of 690; metal ratio of 18 .sup.4Ca Sulfonate 3: Overbased
calcium sulfonate with oil free TBN of 160; metal ratio of 2.8
.sup.5Ca Phenate: "Neutral" calcium phenate with oil free TBN of
200; metal ratio of 1.2 .sup.6Na Sulfonate: Overbased Na sulfonate
with oil free TBN of 650 .sup.7Mg Sulfonate: Overbased Mg sulfonate
with oil free TBN of 600 .sup.8Combination of alkylated diarylamine
and hindered phenol antioxidants .sup.9Dispersant: PIBsuccinimide
prepared from 2000 Mn PIB .sup.10The Additional Additives used in
the examples include friction modifiers, pourpoint depressants,
anti-foam agents, corrosion inhibitors, and includes some amount of
diluent oil
TABLE-US-00005 TABLE 2 Lubricating Oil Composition Formulations
(5W-30) EX7 EX8 EX9 EX10 EX11 EX12 EX13 Group III Base Oil Balance
to = 100% Ca Sulfonate.sup.2 2.78 1.12 1.12 0.95 2.62 0.29 2.78 Mg
Sulfonate.sup.3 0 0 0 0 0 2.92 0 Na Sulfonate 0 0 0 0.15 0 0 0 Ca
Phenate.sup.4 0 0 0 0 0.58 0 0 Dispersant 2.72 2.72 2.72 2.72 2.0
2.0 2.0 Ashless Antioxidant.sup.5 1.6 1.6 1.6 1.6 0.85 0.85 0.85
ZDDP 0.32 0.32 0.77 0.77 0.32 0.32 0.32 VI Improver 0.6 0.6 0.6 0.6
0.6 0.4 0.6 Additional Additives.sup.6 0.9 0.9 0.9 0.9 0.36 0.36
0.36 % Calcium 0.75 0.25 0.25 0.21 0.72 0.064 0.71 % Magnesium 0 0
0 0 0 0.42 0 % Sodium 0 0 0 0.045 0 0 0 Sulfated Ash 2.52 0.92 0.99
0.99 2.52 2.26 2.52 % Phosphorus 0.03 0.03 0.076 0.076 0.03 0.03
0.03 1 - All amounts shown above are in weight percent and are on
an oil-free basis unless otherwise noted less otherwise noted.
.sup.2Ca Sulfonate is one or more overbased calcium alkylbenzene
sulfonic acid with TBN at least 300 and metal ratio at least 10
.sup.3Overbased magnesium sulfonate with TBN of ~600 .sup.4Sulfur
coupled phenate salt of calcium with TBN of ~200 .sup.5Ashless
antioxidant - mixture of nonylated and dinonylatyd diphenylamine,
hindered phenol ester and sulfurized olefin .sup.6The Additional
Additives used in the examples include friction modifiers,
pourpoint depressants, anti-foam agents, corrosion inhibitors, and
includes some amount of diluent oil.
Testing
[0107] Low Speed Pre-ignition events are measured in two engines, a
Ford 2.0 L Ecoboost engine and a GM 2.0 L Ecotec. Both of these
engines are turbocharged gasoline direct injection (GDI) engines.
The Ford Ecoboost engine is operated in two stages. In the first
stage, the engine is operated at 1500 rpm and 14.4 bar break mean
effective pressure (BMEP). During the second stage, the engine is
operated at 1750 rpm and 17.0 bar BMEP. The engine is run for
25,000 combustion cycles in each stage, and LSPI events are
counted.
[0108] The GM Ecotec engine is operated at 2000 rpm and 22.0 bar
BMEP with an oil sump temperature of 100.degree. C. The test
consists of nine phases of 15,000 combustion cycles with each phase
separated by an idle period. Thus, combustion events are counted
over 135,000 combustion cycles.
[0109] LSPI events are determined by monitoring peak cylinder
pressure (PP) and mass fraction burn (MFB) of the fuel charge in
the cylinder. When both criteria are met, it is determined that an
LSPI event has occurred. The threshold for peak cylinder pressure
is typically 9,000 to 10,000 kPa. The threshold for MFB is
typically such that at least 2% of the fuel charge is burned late,
i.e. 5.5 degrees After Top Dead Center (ATDC). LSPI events can be
reported as events per 100,000 combustion cycles, events per cycle,
and/or combustion cycles per event.
TABLE-US-00006 TABLE 4 GM Ecotec LSPI Testing EX7 EX8 EX9 EX10 EX11
EX12 EX13 PP Events 26 17 11 6 33 4 44 MFB Events 29 18 12 7 36 3
46 Total Events 26 17 11 6 32 3 43 Total Cycles 135000 135000
135000 135000 135000 135000 135000 Ave. PP 18440 20670 20520 13300
18980 17370 18860 Events per 100,000 cycles 19.2 12.6 8.1 4.4 23.7
2.2 31.8 Cycles per event 5192 7941 12273 22500 4219 45000 3140
[0110] The data indicates that a reduction in total detergent ash
below 1 weight percent results in a reduction in LSPI events.
Partial replacement of calcium detergent with magnesium and/or
sodium detergent also provided an observed reduction in LSPI
events. In addition, partial replacement of sulfonate detergent
with phenate-based detergent resulted in a reduction in observable
LSPI events.
[0111] It is known that some of the materials described above may
interact in the final formulation, so that the components of the
final formulation may be different from those that are initially
added. The products formed thereby, including the products formed
upon employing lubricant composition of the present invention in
its intended use, may not be susceptible of easy description.
Nevertheless, all such modifications and reaction products are
included within the scope of the present invention; the present
invention encompasses lubricant composition prepared by admixing
the components described above.
[0112] Each of the documents referred to above is incorporated
herein by reference, as is the priority document and all related
applications, if any, which this application claims the benefit of.
Except in the Examples, or where otherwise explicitly indicated,
all numerical quantities in this description specifying amounts of
materials, reaction conditions, molecular weights, number of carbon
atoms, and the like, are to be understood as modified by the word
"about." Unless otherwise indicated, each chemical or composition
referred to herein should be interpreted as being a commercial
grade material which may contain the isomers, by-products,
derivatives, and other such materials which are normally understood
to be present in the commercial grade. However, the amount of each
chemical component is presented exclusive of any solvent or diluent
oil, which may be customarily present in the commercial material,
unless otherwise indicated. It is to be understood that the upper
and lower amount, range, and ratio limits set forth herein may be
independently combined. Similarly, the ranges and amounts for each
element of the invention may be used together with ranges or
amounts for any of the other elements.
[0113] As used herein, the term "hydrocarbyl substituent" or
"hydrocarbyl group" is used in its ordinary sense, which is
well-known to those skilled in the art. Specifically, it refers to
a group having a carbon atom directly attached to the remainder of
the molecule and having predominantly hydrocarbon character.
Examples of hydrocarbyl groups include i) hydrocarbon substituents,
that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g.,
cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-,
and alicyclic-substituted aromatic substituents, as well as cyclic
substituents wherein the ring is completed through another portion
of the molecule (e.g., two substituents together form a ring); (ii)
substituted hydrocarbon substituents, that is, substituents
containing non-hydrocarbon groups which, in the context of this
invention, do not alter the predominantly hydrocarbon nature of the
substituent (e.g., halo (especially chloro and fluoro), hydroxy,
alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulphoxy);
(iii) hetero substituents, that is, substituents which, while
having a predominantly hydrocarbon character, in the context of
this invention, contain other than carbon in a ring or chain
otherwise composed of carbon atoms.
[0114] Heteroatoms include sulfur, oxygen, nitrogen, and encompass
substituents as pyridyl, furyl, thienyl and imidazolyl. In general,
no more than two, preferably no more than one, non-hydrocarbon
substituent will be present for every ten carbon atoms in the
hydrocarbyl group; typically, there will be no non-hydrocarbon
substituents in the hydrocarbyl group.
[0115] While the invention has been explained in relation to its
preferred embodiments, it is to be understood that various
modifications thereof will become apparent to those skilled in the
art upon reading the specification. Therefore, it is to be
understood that the invention disclosed herein is intended to cover
such modifications as fall within the scope of the appended
claims.
* * * * *