U.S. patent application number 15/750254 was filed with the patent office on 2018-08-09 for lubricating compositions for preventing or reducing pre-ignition in an engine.
The applicant listed for this patent is TOTAL MARKETING SERVICES. Invention is credited to Nicolas OBRECHT.
Application Number | 20180223215 15/750254 |
Document ID | / |
Family ID | 54329779 |
Filed Date | 2018-08-09 |
United States Patent
Application |
20180223215 |
Kind Code |
A1 |
OBRECHT; Nicolas |
August 9, 2018 |
LUBRICATING COMPOSITIONS FOR PREVENTING OR REDUCING PRE-IGNITION IN
AN ENGINE
Abstract
Disclosed is a lubricating composition including at least one
base oil and at least one organomolybdenum compound selected from
the molybdenum dithiophosphate compounds or the sulphur-free
molybdenum complexes, for preventing or reducing pre-ignition in an
engine, preferably in a vehicle engine.
Inventors: |
OBRECHT; Nicolas;
(Meistratzheim, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOTAL MARKETING SERVICES |
Puteaux |
|
FR |
|
|
Family ID: |
54329779 |
Appl. No.: |
15/750254 |
Filed: |
August 5, 2016 |
PCT Filed: |
August 5, 2016 |
PCT NO: |
PCT/EP2016/068720 |
371 Date: |
March 16, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 2223/045 20130101;
C10M 2203/1006 20130101; C10M 2215/064 20130101; C10M 159/18
20130101; C10N 2010/04 20130101; C10N 2010/12 20130101; C10M
2203/1025 20130101; C10M 2215/28 20130101; C10M 137/10 20130101;
C10N 2040/255 20200501; C10M 139/00 20130101; C10M 2203/024
20130101; C10M 2205/026 20130101; C10M 2219/046 20130101; C10M
2205/04 20130101; C10M 2227/066 20130101; C10N 2030/02 20130101;
C10M 2203/024 20130101; C10N 2020/02 20130101; C10M 2203/1025
20130101; C10N 2020/02 20130101; C10M 2205/026 20130101; C10M
2205/04 20130101; C10N 2060/02 20130101; C10M 2205/04 20130101;
C10M 2205/06 20130101; C10N 2060/02 20130101; C10M 2223/045
20130101; C10N 2010/04 20130101; C10M 2203/024 20130101; C10N
2020/02 20130101; C10M 2203/1025 20130101; C10N 2020/02 20130101;
C10M 2223/045 20130101; C10N 2010/04 20130101; C10M 2205/026
20130101; C10M 2205/04 20130101; C10N 2060/02 20130101; C10M
2205/04 20130101; C10M 2205/06 20130101; C10N 2060/02 20130101 |
International
Class: |
C10M 139/00 20060101
C10M139/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2015 |
FR |
1557585 |
Claims
1-11. (canceled)
12. Method of prevention or reduction of pre-ignition in a vehicle
engine, wherein the method comprises at least one step of
contacting a mechanical part of the engine with a lubricating
composition comprising at least one base oil and at least one
organomolybdenum compound wherein the organomolybdenum compound is
selected from among sulfur-free molybdenum complexes.
13. Method according to claim 12, wherein the organomolybdenum
compound is a sulfur-free molybdenum complex selected from among
organic complexes of molybdenum with ligands of amide type and
prepared via reaction of a molybdenum source, an amine derivative
and fatty acids.
14. Method according to claim 12, wherein the organomolybdenum
compound is a sulfur-free molybdenum complex and comprising at
least one compound selected from among: compounds of formula (A):
##STR00014## where: X.sup.1 is an oxygen atom or nitrogen atom;
X.sup.2 is an oxygen atom or nitrogen atom; n is 1 when X.sup.1 is
an oxygen atom and m is 1 when X.sup.2 is an oxygen atom; n is 2
when X.sup.1 is a nitrogen atom and m is 2 when X.sup.2 is a
nitrogen atom; R.sub.1 is an alkyl group, linear or branched,
saturated or unsaturated, comprising from 3 to 30 carbon atoms;
compounds of formula (B) ##STR00015## where: X.sup.1 is an oxygen
atom or nitrogen atom; X.sup.2 is an oxygen atom or nitrogen atom;
n is 1 when X.sup.1 is an oxygen atom and m is 1 when X.sup.2 is an
oxygen atom; n is 2 when X.sup.1 is a nitrogen atom and m is 2 when
X.sup.2 is a nitrogen atom; R.sub.1 is a an alkyl group, linear or
branched, saturated or unsaturated, comprising from 3 to 30 carbon
atoms; R.sub.2 is an alkyl group, linear or branched, saturated or
unsaturated, comprising from 3 to 30 carbon atoms, a mixture of at
least one compound of formula (A) and at least one compound of
formula (B).
15. Method according to claim 12, wherein the organomolybdenum
compound is a sulfur-free molybdenum complex and comprising at
least one compound of formula (A1): ##STR00016## where R.sub.1 is
an alkyl group, linear or branched, saturated or unsaturated,
comprising from 3 to 30 carbon atoms.
16. Method according to claim 15, wherein the organomolybdenum
compound is a sulfur-free molybdenum complex and comprising a
compound of formula (A1) where R.sub.1 is an alkyl group comprising
11 carbon atoms.
17. Method according to claim 12, wherein the organomolybdenum
compound is a sulfur-free molybdenum complex and comprising at
least one compound of formula (A2) ##STR00017## where R1 is a alkyl
group, linear or branched, saturated or unsaturated, comprising
from 3 to 30 carbon atoms.
18. Method according to claim 12, wherein the weight content of
organomolybdenum compound relative to the total weight of the
lubricating composition ranges from 0.05 to 3%.
19. Method according to claim 12, wherein the lubricating
composition further comprises an additional additive selected from
among friction modifiers with the exception of sulfur-free
molybdenum complexes, detergents, anti-wear additives, extreme
pressure additives, viscosity index improvers, dispersants,
antioxidants, pour point depressants, defoamers, thickeners and
mixtures thereof.
20. Method according to claim 12 to prevent or reduce pre-ignition
in a motor vehicle.
21. Method according to claim 12 to prevent or reduce Low Speed
Pre-Ignition (LSPI) in an engine.
Description
[0001] The invention relates to the use of a lubricating
composition for preventing or reducing pre-ignition in an engine.
More particularly, the invention relates to the use of a
lubricating composition comprising at least one base oil and at
least one organomolybdenum compound for preventing or reducing
pre-ignition in an engine, preferably in a vehicle engine, in
particular of a motor vehicle.
[0002] The present invention also relates to a method for
preventing or reducing pre-ignition in an engine, preferably in a
vehicle engine, especially of a motor vehicle, implementing this
lubricating composition.
[0003] The present invention also relates to the use of an
organomolybdenum compound in a lubricating composition for
preventing or reducing pre-ignition in an engine, preferably in a
vehicle engine, especially of automobiles.
[0004] Technological Background
[0005] Under ideal conditions, normal combustion in a
spark-ignition engine occurs when a mixture of fuel, and in
particular fuel and air, is ignited in the combustion chamber
inside the cylinder by the production of a spark emanating from a
spark plug. Such normal combustion is generally characterized by
the expansion of the flame front through the combustion chamber in
an orderly and controlled manner.
[0006] However, in some cases, the air/fuel mixture may be
prematurely ignited by an ignition source prior to ignition by the
spark of the spark plug, resulting in a phenomenon known as
pre-ignition. It is preferable to reduce or even eliminate
pre-ignition, as this generally results in the presence of a sharp
increase in temperatures and pressures in the combustion chamber,
and may thus lead to a significant negative impact on the
efficiency and the overall performance of an engine. In addition,
pre-ignition may cause significant damage to the cylinders,
pistons, spark plugs and valves in the engine and in some cases may
even lead to engine failure or even engine damage. Recently, Low
Speed Pre-Ignition (LSPI) has been identified, particularly by car
manufacturers, as a potential problem for small engines (or
downsized engines). LSPI typically occurs at low speeds and high
loads, and may cause serious damage to pistons and/or
cylinders.
[0007] Thus it would be desirable to have a lubricant that may
prevent or reduce the risk of pre-ignition, including LSPI.
[0008] Solutions for decreasing the calcium content or increasing
the zinc dithiophosphate or molybdenum dithiocarbamate content in a
lubricant have been described (Takeuchi et al, "Investigation of
Engine Oil Effect on Abnormal Combustion in Turbocharged Direct
Injection--Spark Ignition Engines," SAE Int. J. Fuels Lubr. 5 (3):
1017-1024, 2012 Hirano et al, "Investigation of Engine Oil Effect
Abnormal Combustion in Turbocharged Direct Injection--Spark
Ignition Engines (Part 2)," SAE Technical Paper 2013-01-2569,
2013). However, these solutions remain still insufficient to
significantly reduce pre-ignition and are difficult to implement,
especially in countries where a high level of basicity is required
in fuels. In addition, problems of lubricant stability or
compatibility with post-treatment systems are associated with these
solutions.
[0009] WO2015023559 discloses a method for reducing pre-ignition by
adding, in a lubricating composition, an additive for retarding
ignition, wherein the additive is selected from among organic
compounds comprising at least one aromatic ring. However, these
light organic compounds could cause an excessive increase in
lubricant volatility.
[0010] An object of the present invention is, therefore, to provide
compounds and a lubricating composition comprising these compounds
to overcome all or part of the aforementioned drawbacks.
[0011] Another object of the present invention is to provide a
lubricating composition for preventing or reducing pre-ignition in
an engine and whose formulation is easy to implement.
[0012] Another object of the present invention is to provide a
lubricating composition for preventing or reducing pre-ignition in
an engine while maintaining satisfactory or improved lubrication
properties.
[0013] Another object of the present invention is to provide a
lubrication method for preventing or reducing pre-ignition in an
engine.
SUMMARY OF THE INVENTION
[0014] The invention thus relates to the use of a lubricating
composition comprising at least one base oil and at least one
organomolybdenum compound for preventing or reducing pre-ignition
in an engine, wherein the organomolybdenum compound is chosen from
among: [0015] molybdenum dithiophosphate compounds (Mo-DTP), or
[0016] molybdenum complexes free from sulfur.
[0017] Surprisingly, the Applicant has found that the presence of
at least one organomolybdenum compound chosen from among the Mo-DTP
and sulfur-free molybdenum complexes in a lubricating composition
enables the lubricating composition, once implemented in an engine,
to prevent or reduce pre-ignition in the engine.
[0018] Thus, the present invention makes it possible to formulate
lubricating compositions providing both good stability and good
pre-ignition prevention or reduction properties when used in an
engine.
[0019] Advantageously, the lubricating compositions according to
the invention have good pre-ignition prevention or reduction
properties once they are implemented in an engine without the need
to associate them with other technical solutions to prevent or
reduce pre-ignition, and in particular technical solutions
requiring the reduction of the calcium or magnesium content or
causing an excessive increase in the volatility of the lubricating
composition.
[0020] Advantageously, the lubricating compositions according to
the invention have good properties for the prevention or reduction
of pre-ignition when implemented in an engine, and whose
formulation is easy to implement.
[0021] In one embodiment according to the invention, the
organomolybdenum compound is a sulfur-free molybdenum complex
selected from among organic molybdenum complexes with amide ligands
and prepared by reaction of a molybdenum source and a derivative of
amino, and of fatty acids preferably comprising from 4 to 28 carbon
atoms, more preferably from 8 to 18 carbon atoms.
[0022] In another embodiment according to the invention, the
organomolybdenum compound is a sulfur-free molybdenum complex
comprising at least one compound chosen from among: [0023] the
compounds of formula (A)
[0023] ##STR00001## [0024] in which [0025] X.sup.1 represents an
oxygen atom or a nitrogen atom; [0026] X.sup.2 represents an oxygen
atom or a nitrogen atom; [0027] n represents 1 when X.sup.1
represents an oxygen atom and m represents 1 when X.sup.2
represents an oxygen atom; [0028] n represents 2 when X.sup.1
represents a nitrogen atom and m represents 2 when X.sup.2
represents a nitrogen atom; [0029] R.sup.1 represents a linear or
branched, saturated or unsaturated alkyl group comprising from 3 to
30 carbon atoms, preferably from 3 to 20 carbon atoms,
advantageously from 7 to 17 carbon atoms; [0030] the compounds of
formula (B)
[0030] ##STR00002## [0031] in which [0032] X.sup.1 represents an
oxygen atom or a nitrogen atom; [0033] X.sup.2 represents an oxygen
atom or a nitrogen atom; [0034] n represents 1 when X.sup.1
represents an oxygen atom and m represents 1 when X.sup.2
represents an oxygen atom; [0035] n represents 2 when X.sup.1
represents a nitrogen atom and m represents 2 when X.sup.2
represents a nitrogen atom; [0036] R.sup.1 represents a linear or
branched, saturated or unsaturated alkyl group comprising from 3 to
30 carbon atoms, preferably from 3 to 20 carbon atoms,
advantageously from 7 to 17 carbon atoms; [0037] R.sup.2 represents
a linear or branched, saturated or unsaturated alkyl group
comprising from 3 to 30 carbon atoms, preferably from 3 to 20
carbon atoms, advantageously from 7 to 17 carbon atoms. [0038] a
mixture of at least one compound of formula (A) and at least one
compound of formula (B).
[0039] In another embodiment of the invention, the organomolybdenum
compound is a sulfur-free molybdenum complex comprising at least
one compound of formula (A1)
##STR00003##
[0040] in which R.sup.1 represents a linear or branched, saturated
or unsaturated alkyl group comprising from 3 to 30 carbon atoms,
preferably from 3 to 20 carbon atoms, advantageously from 7 to 17
carbon atoms.
[0041] In another embodiment of the invention, the organomolybdenum
compound is a sulfur-free molybdenum complex comprising a compound
of formula (A1) in which R.sup.1 represents an alkyl group
comprising 11 carbon atoms.
[0042] In another embodiment of the invention, the organomolybdenum
compound is a sulfur-free molybdenum complex comprising at least
one compound of formula (A2)
##STR00004##
[0043] in which R.sup.1 represents a linear or branched, saturated
or unsaturated alkyl group comprising from 3 to 30 carbon atoms,
preferably from 3 to 20 carbon atoms, advantageously from 7 to 17
carbon atoms.
[0044] In another embodiment of the invention, the organomolybdenum
compound is a Mo-DTP compound comprising: [0045] from 1 to 40%,
preferably from 2 to 30%, more preferably from 3 to 28%, still more
preferably from 4 to 15%, advantageously from 5 to 12 wt.-% of
molybdenum, relative to the total weight of the Mo-DTP compound;
[0046] from 1 to 40%, preferably from 2 to 30%, more preferably
from 3 to 28%, even more preferentially from 4 to 15 wt.-% of
sulfur, relative to the total weight of the Mo-DTP compound; [0047]
from 1 to 10%, preferably from 2 to 8%, more preferably from 3 to 6
wt.-% of phosphorus, relative to the total weight of the total
weight of the Mo-DTP compound.
[0048] In another embodiment of the invention, the Mo-DTP compound
is selected from among dimeric Mo-DTP compounds or trimeric Mo-DTP
compounds.
[0049] In another embodiment of the invention, the Mo-DTP compound
is a dimeric Mo-DTP compound of formula (C)
##STR00005## [0050] in which [0051] R3, R4, R9 and R10, which are
identical or different, independently represent a hydrocarbon group
chosen from alkyl, alkenyl, aryl, cycloalkyl or cycloalkenyl
groups, [0052] R5, R6, R7 and R8, which are identical or different,
independently represent an oxygen atom or a sulfur atom.
[0053] In another embodiment of the invention, the Mo-DTP compound
is a dimeric Mo-DTP compound of formula (C1)
##STR00006##
[0054] in which R3, R4, R9 and R10, which are identical or
different, independently represent a hydrocarbon group chosen from
among alkyl, alkenyl, aryl, cycloalkyl or cycloalkenyl groups,
preferably an alkyl group comprising from 4 to 12 carbon atoms,
advantageously from 6 to at 10 carbon atoms.
[0055] In another embodiment of the invention, the compound Mo-DTP
is a dimeric Mo-DTP compound of formula (C1) in which R3, R4, R9
and R10, which are identical, represent a C8-alkyl group,
preferably an ethylhexyl group.
[0056] In another embodiment of the invention, the content by
weight of organomolybdenum compound, relative to the total weight
of the lubricating composition, ranges from 0.05 to 3%, preferably
from 0.1 to 2%, advantageously from 0.1 to 1%.
[0057] In another embodiment of the invention, the lubricating
composition further comprises an additional additive chosen from
among friction modifiers with the exception of Mo-DTP compounds and
sulfur-free molybdenum complexes, detergents, anti-doping and
anti-wear additives, extreme pressure additives, viscosity index
improvers, dispersants, antioxidants, pour point improvers,
defoamers, thickeners and mixtures thereof.
[0058] In another embodiment of the invention, the lubricating
composition is used to prevent or reduce pre-ignition in a vehicle
engine, preferably of a motor vehicle.
[0059] In another embodiment of the invention, the lubricating
composition is used to prevent or reduce low speed pre-ignition
(LSPI) in an engine preferably of a vehicle, preferably of a motor
vehicle.
[0060] The invention also relates to a method for preventing or
reducing pre-ignition in an engine, wherein the method comprises at
least one step of contacting a mechanical part of the engine with a
lubricating composition as defined above.
[0061] The invention also relates to the use of an organomolybdenum
compound in a lubricating composition comprising at least one base
oil for preventing or reducing pre-ignition in an engine, wherein
the organomolybdenum compound is chosen from among: [0062]
molybdenum dithiophosphate compounds (Mo-DTP), or [0063] molybdenum
complexes free from sulfur.
DETAILED DESCRIPTION OF THE INVENTION
[0064] The percentages given below correspond to percentages by
weight of active ingredient.
[0065] The lubricating composition used according to the invention
comprises at least one organomolybdenum compound chosen from among:
[0066] molybdenum dithiophosphate compounds (Mo-DTP), or [0067]
molybdenum complexes free from sulfur.
[0068] Molybdenum Complex Free from Sulfur
[0069] In one embodiment of the invention, the organomolybdenum
compound may be chosen from among sulfur-free molybdenum complexes
such as carboxylates, esters or molybdenum amides, obtainable by
reaction of molybdenum oxide or molybdates of ammonium with fatty
substances, glycerides, fatty acids or fatty acid derivatives
(esters, amines, amides . . . ).
[0070] In a preferred embodiment of the invention, the
organomolybdenum compound is selected from among sulfur-free
molybdenum complexes with amide ligands, mainly prepared by
reaction of a molybdenum source, which may be, for example,
molybdenum, and an amine derivative, and fatty acids preferably
comprising from 4 to 28 carbon atoms, more preferably from 8 to 18
carbon atoms, such as, for example, the fatty acids contained in
vegetable or animal oils.
[0071] The synthesis of such compounds is described, for example,
in U.S. Pat. No. 4,889,547, EP 0546357, U.S. Pat. No. 5,412,130 and
EP 1770153.
[0072] In a preferred embodiment of the invention, the
organomolybdenum compound is chosen from among sulfur-free
molybdenum complexes obtained by reaction: [0073] (i) a mono-, di-
or tri-glyceride-type fatty substance, or fatty acid, [0074] (ii)
an amino source of formula (D):
[0074] ##STR00007## [0075] in which: [0076] X.sup.1 represents an
oxygen atom or a nitrogen atom, [0077] X.sup.2 represents an oxygen
atom or a nitrogen atom, [0078] n and m represent 1 when X.sup.1 or
X.sup.2 represent an oxygen atom, [0079] n and m represent 2 when
X.sup.1 or X.sup.2 represent a nitrogen atom, [0080] (iii) and a
molybdenum source selected from among molybdenum trioxide or
molybdates, preferably ammonium molybdate, in an amount sufficient
to provide 0.1 to 30% molybdenum based on the total weight of
complex.
[0081] In one embodiment of the invention, the sulfur-free
molybdenum complex may comprise from 2 to 8.5% by weight of
molybdenum based on the weight of complex.
[0082] In a preferred embodiment of the invention, the molybdenum
sulfur complex comprises at least one compound selected from among:
[0083] the compounds of formula (A)
[0083] ##STR00008## [0084] in which: [0085] X.sup.1 represents an
oxygen atom or a nitrogen atom; [0086] X.sup.2 represents an oxygen
atom or a nitrogen atom; [0087] n represents 1 when X.sup.1
represents an oxygen atom and m represents 1 when X.sup.2
represents an oxygen atom; [0088] n represents 2 when X.sup.1
represents a nitrogen atom and m represents 2 when X.sup.2
represents a nitrogen atom; [0089] R.sup.1 represents a linear or
branched, saturated or unsaturated alkyl group comprising from 3 to
30 carbon atoms, preferably from 3 to 20 carbon atoms,
advantageously from 7 to 17 carbon atoms; [0090] the compounds of
formula (B)
[0090] ##STR00009## [0091] in which: [0092] X.sup.1 represents an
oxygen atom or a nitrogen atom; [0093] X.sup.2 represents an oxygen
atom or a nitrogen atom; [0094] n represents 1 when X.sup.1
represents an oxygen atom and m represents 1 when X.sup.2
represents an oxygen atom; [0095] n represents 2 when X.sup.1
represents a nitrogen atom and m represents 2 when X.sup.2
represents a nitrogen atom; [0096] R.sup.1 represents a linear or
branched, saturated or unsaturated alkyl group comprising from 3 to
30 carbon atoms, preferably from 3 to 20 carbon atoms,
advantageously from 7 to 17 carbon atoms; [0097] R.sup.2 represents
a linear or branched, saturated or unsaturated alkyl group
comprising from 3 to 30 carbon atoms, preferably from 3 to 20
carbon atoms, advantageously from 7 to 17 carbon atoms. [0098] a
mixture of at least one compound of formula (A) and at least one
compound of formula (B).
[0099] In one embodiment of the invention, the sulfur-free
molybdenum complex is prepared by reacting: [0100] (i) a mono-, di-
or tri-glyceride-type fatty substance, or fatty acid, [0101] (ii) a
diethanolamine or 2- (2-aminoethyl) aminoethanol, [0102] (iii) and
a molybdenum source selected from among molybdenum trioxide or
molybdates, preferably ammonium molybdate, in an amount sufficient
to provide 0.1 to 20.0% molybdenum based on the weight of the
complex.
[0103] In a preferred embodiment of the invention, the molybdenum
sulfur complex comprises at least one compound of formula (A1) or a
compound of formula (A2), taken alone or as a mixture:
##STR00010##
[0104] in which R.sup.1 represents a linear or branched, saturated
or unsaturated alkyl group comprising from 3 to 30 carbon atoms,
preferably from 3 to 20 carbon atoms, advantageously from 7 to 17
carbon atoms,
##STR00011##
[0105] in which R.sup.1 represents a linear or branched, saturated
or unsaturated alkyl group comprising from 3 to 30 carbon atoms,
preferably from 3 to 20 carbon atoms, advantageously from 7 to 17
carbon atoms.
[0106] Advantageously, the organomolybdenum compound is a
sulfur-free molybdenum complex comprising a compound of formula
(A1) in which R.sup.1 represents an alkyl group comprising 11
carbon atoms.
[0107] Examples of sulfur-free molybdenum complexes include Molyvan
855 marketed by R.T Vanderbilt Company.
[0108] Molybdenum Dithiophosphate Compound (Mo-DTP)
[0109] The molybdenum dithiophosphate (Mo-DTP) compounds are
complexes formed by a metal ring bonded to one or more ligands,
wherein the ligand is an alkyl dithiophosphate group.
[0110] In one embodiment, the Mo-DTP compound used in the
lubricating compositions according to the invention may comprise
from 1 to 40%, preferably from 2 to 30%, more preferably from 3 to
28%, even more preferably from 4 to 15%, advantageously from 5 to
12% by weight of molybdenum, relative to the total weight of Mo-DTP
compound.
[0111] In one embodiment, the Mo-DTP compound used in the
lubricating compositions according to the invention may comprise
from 1 to 40%, preferably from 2 to 30%, more preferably from 3 to
28%, even more preferably from 4 to 15% by weight of sulfur,
relative to the total weight of Mo-DTP compound.
[0112] In one embodiment, the Mo-DTP compound used in the
lubricating compositions according to the invention may comprise
from 1 to 10%, preferably from 2 to 8%, more preferably from 3 to
6% by weight of phosphorus, relative to the total weight of the
total weight of the Mo-DTP compound.
[0113] The Mo-DTP compound used in the lubricating compositions
according to the invention may be chosen from compounds whose
structure comprises two molybdenum atoms (also called dimeric
Mo-DTP) and compounds whose structure comprises three molybdenum
atoms (also called trimeric Mo-DTP).
[0114] The trimeric Mo-DTP compound has the following formula
Mo.sub.3S.sub.kL.sub.n in which: [0115] k represents an integer at
least equal to 4, preferably from 4 to 10, advantageously from 4 to
7, [0116] n represents an integer ranging from 1 to 4, and [0117] L
represents an alkyl dithiophosphate group comprising from 1 to 100
carbon atoms, preferably from 1 to 40 carbon atoms, advantageously
from 3 to 20 carbon atoms.
[0118] Examples of Mo-DTP-trimer compounds according to the
invention include compounds and methods for their preparation as
described in WO98/26030 and US2003/022954.
[0119] Advantageously, the Mo-DTP compound used in the context of
the invention is a dimeric Mo-DTP compound.
[0120] Examples of dimeric Mo-DTP compounds include the compounds
as described in EP0757093 or EP0743354.
[0121] Dimeric Mo-DTP generally corresponds to the compounds of
formula (C):
##STR00012## [0122] in which: [0123] R3, R4, R9 and R10, which may
be identical or different, independently represent a hydrocarbon
group chosen from alkyl, alkenyl, aryl, cycloalkyl or cycloalkenyl
groups, [0124] R5, R6, R7 and R8, which may be identical or
different, independently represent an oxygen atom or a sulfur
atom.
[0125] In one embodiment, R3, R4, R9 and R10, which may be
identical or different, independently represent an alkyl group
comprising from 4 to 18 carbon atoms or an alkenyl group comprising
from 2 to 24 carbon atoms.
[0126] In one embodiment, R5, R6, R7 and R8 may be identical and
may represent a sulfur atom.
[0127] In another embodiment, R5, R6, R7 and R8 may be identical
and may represent an oxygen atom.
[0128] In another embodiment, R5 and R6 may represent a sulfur
atom, while R7 and R8 may represent an oxygen atom.
[0129] In another embodiment, R5 and R6 may represent an oxygen
atom, while R7 and R8 may represent a sulfur atom.
[0130] In a preferred embodiment of the invention, the compound
Mo-DTP is chosen from among compounds of formula (C) in which:
[0131] R5 and R6 represent an oxygen atom, [0132] R7 and R8
represent a sulfur atom, [0133] R3 represents an alkyl group
comprising from 4 to 12 carbon atoms, preferably from 6 to 10
carbon atoms, [0134] R4 represents an alkyl group comprising from 4
to 12 carbon atoms, preferably from 6 to 10 carbon atoms, [0135] R9
represents an alkyl group comprising from 4 to 12 carbon atoms,
preferably from 6 to 10 carbon atoms, [0136] R10 represents an
alkyl group comprising from 4 to 12 carbon atoms, preferably from 6
to 10 carbon atoms.
[0137] Advantageously, the Mo-DTP compound is chosen from among
compounds of formula (C) in which: [0138] R5 and R6 represent an
oxygen atom, [0139] R7 and R8 represent a sulfur atom, [0140] R3
represents an ethylhexyl group, [0141] R4 represents an ethylhexyl
group, [0142] R9 represents an ethylhexyl group, [0143] R10
represents an ethylhexyl group.
[0144] Advantageously, the compound Mo-DTP is chosen from compounds
of formula (C1)
##STR00013## [0145] in which R3, R4, R9 and R10 are as defined for
formula (C).
[0146] Advantageously, the compound Mo-DTP is chosen from among
compounds of formula (C1) in which R3, R4, R9 and R10, which are
identical or different, independently represent a hydrocarbon group
chosen from alkyl, alkenyl, aryl, cycloalkyl or cycloalkenyl,
preferably an alkyl group comprising from 4 to 12 carbon atoms,
preferably from 6 to 10 carbon atoms.
[0147] Even more advantageously, the compound Mo-DTP is chosen from
among compounds of formula (C1) in which R3, R4, R9 and R10
represent a C8-alkyl group, preferably an ethylhexyl group.
[0148] As examples of Mo-DTP compounds, mention may be made of the
Molyvan L product marketed by the company R.T Vanderbilt Company or
the Sakuralube 300 or Sakuralube 310G products sold by the company
Adeka.
[0149] In one embodiment of the invention, the content by weight of
organomolybdenum compound, relative to the total weight of the
lubricating composition, ranges from 0.05 to 3%, preferably from
0.1 to 2%, advantageously from 0.1 to 1%.
[0150] The lubricating composition used according to the invention
also comprises at least one base oil.
[0151] In general, the lubricating composition used according to
the invention may comprise any type of mineral, synthetic or
natural, animal or vegetable, lubricating base oil known to persons
skilled in the art.
[0152] The base oils used in the lubricating compositions according
to the invention may be oils of mineral or synthetic origins
belonging to groups I to V according to the classes defined in the
API classification (or their equivalents according to the ATIEL
classification) (Table A), or their mixtures.
TABLE-US-00001 TABLE A Saturated Sulfur Viscosity index content
content (VI) Group I Mineral oils <90% >0.03% 80 .ltoreq. VI
< 120 Group II Hydrocracked .gtoreq.90% .ltoreq.0.03% 80
.ltoreq. VI < 120 oils Group III Hydrocracked .gtoreq.90%
.ltoreq.0.03% .gtoreq.120 or hydro-isomerized oils Group IV
Polyalphaolefines (PAO) Polyalphaolefines (PAO) Group V Esters and
other bases not included in groups I to IV
[0153] The mineral base oils according to the invention include all
types of base oils obtained by atmospheric and vacuum distillation
of crude oil, followed by refining operations such as solvent
extraction, desalting, solvent dewaxing, hydrotreating,
hydrocracking, hydroisomerization and hydrofinishing.
[0154] Mixtures of synthetic and mineral oils may also be used.
[0155] There is generally no limitation on the use of different
lubricating bases for producing the lubricating compositions used
according to the invention, except that they must have properties,
in particular viscosity, viscosity index, sulfur, oxidation
resistance, that are suitable for use for engines or for vehicle
transmissions.
[0156] The base oils of the lubricating compositions used according
to the invention may also be chosen from synthetic oils, such as
certain carboxylic acid esters and alcohols, and from
polyalphaolefins. The polyalphaolefins used as base oils are, for
example, obtained from monomers comprising from 4 to 32 carbon
atoms, for example from octene or decene, and whose viscosity at
100.degree. C. is between 1.5 and 15 mm.sup.2.s.sup.-1 according to
ASTM D445. Their average molecular weight is generally between 250
and 3000 according to ASTM D5296.
[0157] Preferably, the base oils of the present invention are
chosen from the above base oils whose aromatic content is between 0
and 45%, preferably between 0 and 30%. The aromatic content of the
oils is measured according to the Burdett UV method.
[0158] Advantageously, the lubricating composition used according
to the invention comprises at least 50% by weight of base oils
relative to the total weight of the composition.
[0159] More advantageously, the lubricating composition used
according to the invention comprises at least 60% by weight, or
even at least 70% by weight, of base oils relative to the total
weight of the composition.
[0160] More particularly advantageously, the lubricating
composition used according to the invention comprises from 60 to
99.5% by weight of base oils, preferably from 70 to 99.5% by weight
of base oils, relative to the total weight of the composition.
[0161] Many additives may be used for this lubricating composition
used according to the invention.
[0162] The preferred additives for the lubricating composition used
according to the invention are chosen from among friction modifiers
with the exception of Mo-DTP compounds and sulfur-free molybdenum
complexes, detergents, anti-wear additives, extreme pressure
additives, viscosity index improvers, dispersants, antioxidants,
pour point improvers, defoamers, thickeners and mixtures
thereof.
[0163] Preferably, the lubricating composition used according to
the invention comprises at least one anti-wear additive, and at
least one extreme pressure additive or their mixtures.
[0164] The anti-wear additives and extreme pressure additives
protect the friction surfaces by forming a protective film adsorbed
on these surfaces.
[0165] There is a wide variety of anti-wear additives. In a
preferred manner for the lubricating composition according to the
invention, wherein the anti-wear additives are chosen from among
phospho-sulfur-containing additives such as metal
alkylthiophosphates, in particular zinc alkylthiophosphates, and
more specifically zinc dialkyldithiophosphates or ZnDTPs. The
preferred compounds have the formula
Zn((SP(S)(OR.sup.11)(OR.sup.12)).sub.2, in which R.sup.11 and
R.sup.12, which may be identical or different, independently
represent an alkyl group, preferably an alkyl group comprising from
1 to 18 carbon atoms.
[0166] Amine phosphates are also anti-wear additives that may be
used in the lubricating composition according to the invention.
However, the phosphorus provided by these additives may act as a
poison of the catalytic systems of automobiles because these
additives are ash generators. These effects may be minimized by
partially substituting the amine phosphates with non-phosphorus
additives, such as, for example, polysulfides, especially
sulfur-containing olefins. Advantageously, the lubricating
composition according to the invention may comprise from 0.01 to 6%
by weight, preferably from 0.05 to 4% by weight, more preferably
from 0.1 to 2% by weight relative to the total weight of
lubricating composition, anti-wear additives and extreme pressure
additives.
[0167] Advantageously, the lubricating composition according to the
invention may comprise at least one additional friction-modifying
additive with the exception of Mo-DTP compounds and sulfur-free
molybdenum complexes. The additional friction modifier additive may
be selected from a compound providing metal elements and an ash
free compound. Among the compounds providing metal elements,
mention may be made of transition metal complexes such as Mo, Sb,
Sn, Fe, Cu and Zn, the ligands of which may be hydrocarbon
compounds comprising oxygen, nitrogen, sulfur or phosphorus. The
ashless friction modifier additives are generally of organic origin
and may be selected from monoesters of fatty acids and polyols,
alkoxylated amines, alkoxylated fatty amines, fatty epoxides,
borate fatty epoxides, fatty amines or fatty acid glycerol esters.
According to the invention, the fatty compounds comprise at least
one hydrocarbon group comprising from 10 to 24 carbon atoms.
[0168] Advantageously, the lubricating composition according to the
invention may comprise from 0.01 to 2% by weight or from 0.01 to 5%
by weight, preferably from 0.1 to 1.5% by weight or 0.1 at 2% by
weight relative to the total weight of the lubricating composition,
anti-wear and extreme pressure additives.
[0169] Advantageously, the lubricating composition according to the
invention may comprise at least one antioxidant additive.
[0170] The antioxidant additive generally serves to delay the
degradation of the lubricating composition in use. This degradation
may notably result in the formation of deposits, the presence of
sludge or an increase in the viscosity of the lubricating
composition.
[0171] Antioxidant additives act in particular as radical
inhibitors or destroyers of hydroperoxides. Among the antioxidant
additives commonly used, mention may be made of antioxidant
additives of phenolic type, antioxidant additives of amine type,
antioxidant phosphosulfur additives. Some of these antioxidant
additives, for example phosphosulfur antioxidant additives, may be
ash generators. Phenolic antioxidant additives may be ash-free or
may be in the form of neutral or basic metal salts. The antioxidant
additives may especially be chosen from sterically hindered
phenols, sterically hindered phenol esters and sterically hindered
phenols comprising a thioether bridge, diphenylamines,
diphenylamines substituted by at least one C.sub.1-C.sub.12 alkyl
group, and N, N'-dialkyl-aryl diamines and mixtures thereof.
[0172] Preferably, according to the invention, the sterically
hindered phenols are chosen from compounds comprising a phenol
group in which at least one vicinal carbon of the carbon bearing
the alcohol function is substituted by at least one
C.sub.1-C.sub.10 alkyl group, preferably a C.sub.1-C.sub.6 alkyl
group, preferably a C.sub.4 alkyl group, preferably by the
ter-butyl group.
[0173] Amino compounds are another class of antioxidant additives
that may be used, optionally in combination with phenolic
antioxidant additives. Examples of amine compounds are aromatic
amines, for example aromatic amines of formula
NR.sup.13R.sup.14R.sup.15 in which R.sup.13 represents an
optionally substituted aliphatic or aromatic group, R.sup.14
represents an optionally substituted aromatic group, R.sup.15
represents a hydrogen atom, a alkyl group, an aryl group or a group
of the formula R.sup.16S(O).sub.2R.sup.17 wherein R.sup.16
represents an alkylene group or an alkenylene group, R.sup.17
represents an alkyl group, an alkenyl group or an aryl group and z
represents 0, 1 or 2.
[0174] Sulfurized alkyl phenols or their alkali and alkaline earth
metal salts may also be used as antioxidant additives.
[0175] Another class of antioxidant additives is copper compounds,
for example copper thio- or dithio-phosphates, copper and
carboxylic acid salts, dithiocarbamates, sulphonates, phenates,
copper acetylacetonates. Copper salts I and II, succinic acid or
anhydride salts, may also be used.
[0176] The lubricating composition according to the invention may
contain all types of antioxidant additives known to persons skilled
in the art.
[0177] Advantageously, the lubricating composition comprises at
least one ash-free antioxidant additive.
[0178] Also advantageously, the lubricating composition according
to the invention comprises from 0.5 to 2% by weight relative to the
total weight of the composition, of at least one antioxidant
additive.
[0179] The lubricating composition according to the invention may
also comprise at least one detergent additive.
[0180] The detergent additives generally make it possible to reduce
the formation of deposits on the surface of the metal parts by
dissolving the secondary oxidation and combustion products.
[0181] The detergent additives that may be used in the lubricating
composition according to the invention are generally known to
persons skilled in the art. The detergent additives may be anionic
compounds comprising a long lipophilic hydrocarbon chain and a
hydrophilic head. The associated cation may be a metal cation of an
alkali metal or alkaline earth metal.
[0182] The detergent additives are preferably chosen from the
alkali metal or alkaline earth metal salts of carboxylic acids, the
sulphonates, the salicylates, the naphthenates and the phenate
salts. The alkali and alkaline earth metals are preferably calcium,
magnesium, sodium or barium.
[0183] These metal salts generally comprise the metal in
stoichiometric amount or in excess, therefore in an amount greater
than the stoichiometric amount. It then relates to overbased
detergent additives; the excess metal bringing the overbased
character to the detergent additive is then generally in the form
of an oil insoluble metal salt, for example a carbonate, a
hydroxide, an oxalate, an acetate, a glutamate, preferably a
carbonate.
[0184] Advantageously, the lubricating composition according to the
invention may comprise from 2 to 4% by weight of detergent additive
relative to the total weight of the lubricating composition.
[0185] Also advantageously, the lubricating composition according
to the invention may also comprise at least one pour point
depressant additive.
[0186] By slowing the formation of paraffin crystals, pour point
depressant additives generally improve the cold behavior of the
lubricating composition according to the invention.
[0187] As examples of pour point depressant additives, mention may
be made of alkyl polymethacrylates, polyacrylates, polyarylamides,
polyalkylphenols, polyalkylnaphthalenes and alkylated
polystyrenes.
[0188] Advantageously, the lubricating composition according to the
invention may also comprise at least one dispersing agent.
[0189] The dispersing agent may be chosen from among Mannich bases,
succinimides and their derivatives.
[0190] Also advantageously, the lubricating composition according
to the invention may comprise from 0.2 to 10% by weight of
dispersing agent relative to the total weight of the lubricating
composition.
[0191] The lubricating composition of the present invention may
also comprise at least one additive improving the viscosity index.
Examples of additives which improve the viscosity index include
polymeric esters, homopolymers or copolymers, hydrogenated or
non-hydrogenated, of styrene, butadiene and isoprene, in particular
polyacrylates, polymethacrylates (PMA) or olefin copolymers,
especially ethylene/propylene copolymers.
[0192] The lubricating composition according to the invention may
be in various forms. The lubricating composition according to the
invention may, in particular, be an anhydrous composition.
[0193] Preferably, this lubricating composition is not an
emulsion.
[0194] The lubricating composition defined above is used to prevent
or reduce pre-ignition in an engine.
[0195] By engine according to the invention, is meant more
particularly vehicle engines, such as: [0196] motor vehicle
engines, including petrol and diesel engines, but also gas and
petrol engines (dual fuel gas/gasoline engines) and gas and diesel
engines (dual fuel gas/diesel engines); [0197] the engines of heavy
goods vehicles, and more specifically the engines of heavy goods
vehicles running on gas.
[0198] By engine according to the invention is also meant 4-stroke
engines, and more specifically 4-stroke marine engines, preferably
4-stroke marine engines operating on gas.
[0199] In a preferred embodiment of the invention, the lubricating
composition is used to prevent or reduce pre-ignition in a vehicle
engine, preferably a motor vehicle.
[0200] Pre-ignition according to the invention includes the
phenomenon of low frequency vibration producing a rumble sound
effect. By pre-ignition according to the invention is more
particularly meant low-speed pre-ignition (LSPI).
[0201] In a preferred embodiment of the invention, the lubricating
composition is used to prevent or reduce low speed pre-ignition
(LSPI) in an engine, preferably in a vehicle engine, preferably a
motor vehicle.
[0202] The invention also relates to a method for preventing or
reducing pre-ignition in an engine, wherein the method comprises at
least one step of contacting a mechanical part of the engine with a
lubricating composition as defined above.
[0203] All of the features and preferences described for the above
use also apply to this method.
[0204] The invention also has the use of an organomolybdenum
compound in a lubricating composition comprising at least one base
oil for preventing or reducing pre-ignition in an engine, wherein
the organomolybdenum compound is chosen from: [0205] molybdenum
dithiophosphate compounds (Mo-DTP), or [0206] molybdenum complexes
free from sulfur.
[0207] The set of characteristics and preferences relating to the
organomolybdenum compound and the lubricating composition described
above also apply to this use.
[0208] The various aspects of the invention may be illustrated by
the following examples:
EXAMPLE 1
Preparation of Lubricating Compositions According to the
Invention
[0209] The various components of the lubricating compositions
according to the invention Cl1 and Cl2 are mixed according to the
nature and the quantities presented in Table 1.
TABLE-US-00002 TABLE 1 Cl1 Cl2 Gr III base oil 85.01 84.77
Viscosity Index Improver 5.00 5.00 (Polyisobutene Styrene
Hydrogenated or PISH) Anti-wear (DTPZn) 0.63 0.80 Antioxidant amine
(Diphenylamine) 0.80 0.80 Detergent (Calcium sulphonate) 2.00 2.00
Dispersant (Bis-Succinimide) 6.00 6.00 Mo-DTP (Sakuralube 300) 0.56
Sulfur-Free Molybdenum Complex 0.63 (Molyvan 855) KV 100 (measured
in mm.sup.2/s 8.3 8.3 according to ASTM D445)
EXAMPLE 2
Preparation of Comparative Lubricating Compositions
[0210] The various components of the comparative lubricating
composition CC1 are mixed according to the nature and amounts shown
in Table 2
TABLE-US-00003 TABLE 2 CC1 Gr III base oil 84.90 Viscosity Index
Improver 5.00 (Polyisobutene Styrene Hydrogenated or PISH)
Anti-wear (DTPZn) 0.80 Antioxidant amine (Diphenylamine) 0.80
Detergent (Calcium sulphonate) 2.00 Dispersant (Bis-succinimide)
6.00 Mo-DTC (Sakuralube 525) 0.50 KV 100 (measured in mm.sup.2/s
8.3 according to ASTM D445)
EXAMPLE 3
Evaluation of the Pre-Ignition Reduction Properties of the
Lubricating Compositions according to the invention Cl1 and Cl2 and
of the comparative lubricating composition CC1
[0211] This evaluation is performed by evaluating the impact of
each lubricating composition on the low-speed pre-ignition
(LSPI).
[0212] For this, the LSPI phenomenon is quantified by means of a GM
Ecotech model spark ignition turbocharged engine composed of 4
cylinders in line for a total displacement of 2.0 L.
[0213] After a heating period of 20 minutes at an engine speed of
2000 rpm and an engine load of 4.10.sup.5 Pascal effective average
pressure (EAP), the test procedure consists of 2 sequences under
heavy load (23.10.sup.5 Pascal EAP at a speed of 2.000 rpm), 2
sequences under low load (13.10.sup.5 Pascal of EAP at a speed of
1.250 rpm) and 2 sequences under heavy load identical to the first
2. Each sequence comprises 25.000 motor cycles to ensure a good
statistical representativeness of the phenomenon studied.
[0214] Each cylinder is equipped with a sensor to measure the
pressure in the combustion chamber during engine operation. A high
frequency recorder records the pressure signal allowing a fine
analysis of the combustion. A combustion is considered an LSPI
event if one of the following 2 criteria is fulfilled: [0215] the
maximum pressure of a cycle is greater than the average of the
maximum pressures on the whole sequence considered +4.7 times the
standard deviation of maximum pressure measured on the sequence;
[0216] the crankshaft angle at which 2% of the fuel mixture mass
burned on a given cycle is less than the average of the crankshaft
angles at which 2% of the mass of fuel mixture burned over the
entire sequence considered plus 4.7 times the standard deviation on
the crankshaft angle at which 2% of the mass of combustible mixture
burned on all the frequency.
[0217] The sum of the LSPI events is counted on all 6 sequences of
the procedure for a given lubricating composition. This test is
repeated 4 times for each lubricated composition tested.
[0218] The impact of the lubricating composition on the LSPI is
compared by comparing the average of the number of LSPI events on
the four engine tests and taking into account the standard
deviation calculated on the four engine tests.
[0219] The results concerning the lubricating compositions
according to the invention Cl1 and Cl2 and the comparative
lubricating composition CC1 are given in Table 3; the lower the
number of LSPI events, the better the performance of the
lubricating composition to prevent or reduce pre-ignition.
TABLE-US-00004 TABLE 3 Cl1 Cl2 CC1 Number of LSPI 193 229 324
events
[0220] The results show that the lubricating compositions according
to the invention comprising respectively an Mo-DTP (composition
Cl1) and a sulfur-free molybdenum complex (composition Cl2) exhibit
improved LSPI reduction properties compared to a lubricating
composition comprising a molybdenum dithiocarbamate
organomolybdenum (Mo-DTC) compound.
* * * * *