U.S. patent application number 11/560786 was filed with the patent office on 2007-06-07 for lubricating oil composition.
Invention is credited to Peter Busse, Helmut Leonhardt, Peter Sant, Malcom J. Willars.
Application Number | 20070129266 11/560786 |
Document ID | / |
Family ID | 36178321 |
Filed Date | 2007-06-07 |
United States Patent
Application |
20070129266 |
Kind Code |
A1 |
Busse; Peter ; et
al. |
June 7, 2007 |
Lubricating Oil Composition
Abstract
The use, in a lubricating oil composition comprising base oil,
of one or more magnesium detergents, for the reduction of clogging
in a diesel particulate filter.
Inventors: |
Busse; Peter; (Hamburg,
DE) ; Leonhardt; Helmut; (Hamburg, DE) ; Sant;
Peter; (Cheshire, GB) ; Willars; Malcom J.;
(Cheshire, GB) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
36178321 |
Appl. No.: |
11/560786 |
Filed: |
November 16, 2006 |
Current U.S.
Class: |
508/459 |
Current CPC
Class: |
C10N 2030/18 20130101;
C10N 2030/52 20200501; C10M 2223/045 20130101; C10N 2030/06
20130101; C10M 2219/046 20130101; C10N 2030/12 20130101; C10N
2040/25 20130101; C10N 2030/08 20130101; C10M 159/24 20130101; C10N
2040/253 20200501; C10N 2040/252 20200501; C10M 159/20 20130101;
C10M 2207/028 20130101; C10N 2030/43 20200501; C10M 2203/1006
20130101; C10N 2030/36 20200501; C10N 2030/45 20200501; C10M 159/22
20130101; C10M 167/00 20130101; C10N 2030/42 20200501; C10M
2207/026 20130101; C10N 2010/04 20130101; C10M 2207/262 20130101;
C10N 2030/04 20130101; C10M 2215/28 20130101 |
Class at
Publication: |
508/459 |
International
Class: |
C10L 1/14 20060101
C10L001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 18, 2005 |
EP |
05025191.7 |
Claims
1. A method for reducing clogging in a diesel particulate filter
during operation of a diesel engine that is lubricated with a
lubricating oil, the method comprising including in the lubricating
oil at least one magnesium detergent.
2. The method according to claim 1, wherein the clogging is
measured by the VW diesel particulate filter test.
3. The method according to claim 1 wherein the lubricating oil
composition has a sulphated ash content of not greater than 1.0 wt.
%, based on the total weight of the lubricating oil
composition.
4. The method according to claim 1 wherein the magnesium detergent
is selected from the group consisting of magnesium salicylate
detergents, magnesium phenate detergents, magnesium sulphonate
detergents, and combinations thereof.
5. The method according to claim 4 wherein said at least one
magnesium detergent has a TBN (total base number) value in the
range of from 30 to 600 mg.KOH/g, as measured by ISO 3771.
6. The method according to claim 1 wherein the base oil is selected
from the group consisting of mineral oil, synthetic oil, and
combinations thereof.
7. The method according to claim 1 wherein the magnesium detergent
is present in a total amount of not greater than 0.2 wt. % in terms
of magnesium content, based on the total weight of the lubricating
oil composition.
8. The method according to claim 1 wherein the lubricating oil
composition has a phosphorus content in the range of from 0.04 to
0.1 wt. %, based on the total weight of the lubricating oil
composition.
9. The method according to claim 1 wherein the lubricating oil
composition further comprises one or more additives selected from
anti-oxidants, anti-wear additives, supplementary detergents,
dispersants, friction modifiers, viscosity index improvers, pour
point depressants, corrosion inhibitors, defoaming agents and seal
fix or seal compatibility agents.
10. A method of improving performance in a diesel particulate
filter test, comprising lubricating an internal combustion engine
with a lubricating oil composition containing a magnesium
compound.
11. The method according to claim 1 wherein the filter weight
increases less than 50% after 450 hours of operation, as measured
by the VW diesel particulate filter test.
12. A method for reducing clogging in a diesel particulate filter
during operation of a diesel engine that is lubricated with a
lubricating oil, the method comprising: including in the
lubricating oil at least one magnesium detergent; wherein the
lubricating oil composition has a sulphated ash content of not
greater than 1.0 wt. % and a phosphorus content in the range of
from 0.04 to 0.1 wt. %, based on the total weight of the
lubricating oil composition; and wherein the magnesium detergent is
present in a total amount of not greater than 0.2 wt. % in terms of
magnesium content, based on the total weight of the lubricating oil
composition.
13. The method according to claim 12 wherein the magnesium
detergent is selected from the group consisting of magnesium
salicylate detergents, magnesium phenate detergents, magnesium
sulphonate detergents, and combinations thereof.
14. The method according to claim 12 wherein the base oil is
selected from the group consisting of mineral oil, synthetic oil,
and combinations thereof.
15. The method according to claim 12 wherein the lubricating oil
composition further comprises one or more additives selected from
anti-oxidants, anti-wear additives, supplementary detergents,
dispersants, friction modifiers, viscosity index improvers, pour
point depressants, corrosion inhibitors, defoaming agents and seal
fix or seal compatibility agents.
16. The method according to claim 12 wherein the filter weight
increases less than 50% after 450 hours of operation, as measured
by the VW diesel particulate filter test.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a lubricating oil
composition, in particular to a lubricating oil composition which
is suitable for lubricating internal combustion engines.
BACKGROUND OF THE INVENTION
[0002] In view of the adverse affects that the sulphated ash,
sulphur and phosphorus concentrations of lubricating oil
compositions may have on vehicle exhaust after-treatment devices
such as diesel particulate filters (DPF), there is a trend towards
lubricating oil compositions having reduced sulphated ash, sulphur
and/or phosphorus concentrations therein (i.e. so-called low-SAPS
lubricating oil compositions).
[0003] Phosphorus concentrations may be generally reduced by
reducing the amount of zinc dithiophosphates which are present as
anti-wear additives in lubricating oil compositions.
[0004] Sulphur levels in lubricating oil compositions may be
reduced by employing low sulphur level base oils and reducing the
amount of sulphur-containing additives employed therein.
[0005] Sulphated ash is the total weight percent of residue
remaining after a lubricating oil composition has been carbonised,
and the residue subsequently treated with sulphuric acid and heated
to constant weight. The sulphated ash content in a lubricating oil
composition is related to the total metal content therein.
Sulphated ash may be conveniently measured according to ASTM
D874.
[0006] The major sources of sulphated ash in a lubricating oil
composition are generally any metal detergent additives and zinc
dithiophosphate anti-wear additives that are employed therein.
[0007] Sulphated ash deposits can clog the diesel particulate
filter (DPF) of vehicles, thereby reducing filter life, raising
back pressure in the vehicle engine and causing increased fuel
consumption.
[0008] The tendency of diesel particulate filters to become clogged
can be measured by tests such as the Volkswagen (VW) diesel
particulate filter (DPF) test. This severe diesel particulate
filter test forms part of the VW factory fill specification
52195.
[0009] In order to minimise problems in the diesel particulate
filters of vehicles, in current low-SAPS lubricating oil
compositions, sulphated ash levels, and consequently detergent
levels, are low.
[0010] However, reducing the amount of detergents present in a
lubricating oil composition in order to reduce the sulphated ash
content thereof can have an adverse effect on the basicity of the
lubricating oil composition.
[0011] Total Base Number (TBN) is a measure of how well a
lubricating oil composition can neutralise acidic by-products of
combustion/oxidation and is defined as the quantity of acid,
expressed in terms of the equivalent number of milligrams of
potassium hydroxide, that is required to neutralize all basic
constituents present in 1 gram of a sample of the lubricating oil
composition (test methods include, for example, ISO 3771, ASTM
D-2896 and ASTM D-4739).
[0012] A high TBN is desirable in lubricating oil compositions in
order to control corrosive engine wear from the acidic by-products
of combustion/oxidation. Detergent additives in a lubricating oil
composition are the primary source of basicity (TBN) and help to
control, for example, top-ring deposits and bore polish.
[0013] Hence, metal detergents are the primary source of TBN in
crankcase lubricating oil compositions.
[0014] Consequently, the starting TBN (i.e. of fresh un-used
lubricating oil compositions) of low-SAPS lubricating oil
compositions tends to be lower than in lubricating oil compositions
having higher sulphated ash, sulphur and/or phosphorus
concentrations therein.
[0015] It is therefore highly desirable to be able to reduce the
adverse clogging effect of sulphated ash on the diesel particulate
filter unit without having to compromise on the basicity of the
lubricating oil composition.
[0016] EP-A-1362905 describes fuel oil and lubricating oil
compositions for diesel engines having a diesel particulate filter.
Said compositions comprise a small amount of a molybdenum compound
to improve the combustion property of particulate matter trapped in
a diesel particulate filter.
[0017] Whilst said compositions may comprise additional known
additives for their conventional purposes, it should be noted that
EP-A-1362905 is in no way concerned with using specific additives
to try to reduce clogging in a diesel particulate filter from the
outset.
[0018] In this regard, the bench tests in EP-A-1362905 are designed
merely to show how the afore-mentioned molybdenum compound might be
suitable for use in improving burn-off of calcium and magnesium
deposits. However, there is no disclosure, and indeed no
comparison, in EP-A-1362905 of the degree of clogging of a real
diesel particulate filter from a lubricating oil composition
comprising a calcium or magnesium based detergent.
[0019] U.S. Pat. No. 6,114,288 discloses lubricating oil
compositions for internal combustion engines having a sulphated ash
content in the range of from 0.8 to 1.8 mass % according to JIS
K2272, which compositions comprise base oil, specific zinc dialkyl
dithiophosphates and metallic detergent chosen from i) calcium
alkylsalicylate and ii) a mixture of calcium alkylsalicylate and
magnesium alkylsalicylate.
[0020] Whilst the Examples in U.S. Pat. No. 6,114,288 test the wear
performance of lubricating oil compositions comprising various
alkaline earth metal detergents such as calcium sulphonate,
magnesium sulphonate, calcium salicylate and magnesium salicylate,
it is of note that U.S. Pat. No. 6,114,288 is in no way concerned
with the performance of said lubricating oil compositions in diesel
particulate filter tests, and in particular in the VW diesel
particulate filter test.
[0021] US 2002/0019320 A1 describes lubricating oil compositions
having a low sulphated ash content, a low phosphorus content, and a
low sulphur content. Said lubricating oil compositions are said to
have good detergency at high temperatures.
[0022] Detergents used in the lubricating oil compositions of US
2002/0019320 A1 are those containing an organic acid metal salt
which is selected from the group consisting of a non-sulphurised
alkali metal or alkaline earth metal salt of an alkylsalicylic acid
having a TBN of 10 to 350 mg.KOH/g and a non-sulphurised alkali
metal or alkaline earth metal salt of an alkylphenol derivative
having a Mannich base structure, in an amount of 0.1 to 1 wt. % in
terms of sulphated ash.
[0023] Whilst various alkaline earth detergents are used in the
Examples of US 2002/0019320 A1, it is of note that the preferred
alkaline earth metal is calcium and that none of the lubricating
oil compositions of US 2002/0019320 A1 are actually tested in a
diesel particulate filter test, and in particular in the VW diesel
particulate filter test.
[0024] US 2004/0127371 A1 seeks means to reduce the amount of
metal-containing compounds in lubricating oil compositions in order
that said compositions are more suitable for use in engines
provided with particulate filters.
[0025] US 2004/0127371 A1 indicates that the amount of detergent
needed to neutralise mineral acids generated during the combustion
and ameliorate engine corrosion can be reduced in engines operated
by low sulphur fuels.
[0026] Accordingly, US 2004/0127371 A1 describes a lubricating oil
composition for use in a compression ignited (diesel) internal
combustion engine operated with diesel fuel having a sulphur
content of less than 50 ppm, said lubricating oil composition
comprising a major amount of oil of lubricating viscosity, and at
least one metal-containing detergent, wherein said lubricating oil
composition has a total ash content of less than 1.0 wt. %, based
on the total weight of the lubricating oil composition.
[0027] It will be appreciated that the approach used in US
2004/0127371 A1 reduces the TBN demand placed on a lubricating oil
composition in the first place by reducing generation of acidic
species.
[0028] However, US 2004/0127371 A1 does not provide any teaching on
how to reduce the adverse clogging effect of sulphated ash on the
diesel particulate filter units without having to compromise on the
basicity of the lubricating oil composition.
[0029] US 2004/0176260 A1 discusses accumulation of ash in exhaust
gas after-treatment devices from metal detergents and zinc dialkyl
dithiophosphate additives and the resulting deterioration in
detergency and anti-wear properties if this problem is addressed by
reducing the content of said additives in a lubricating oil
composition.
[0030] US 2004/0176260 A1 discloses means to compensate for this
deterioration by blending specific ashless dispersants and
phosphorus-containing ashless anti-wear additives, alternatively
with a fatty acid amide in specific amounts whilst decreasing the
amounts of zinc dialkyl dithiophosphate and metallic
detergents.
SUMMARY OF THE INVENTION
[0031] It has been surprisingly found in the present invention that
for a given sulphated ash content, the use of magnesium detergents
in lubricating oil compositions give improved performance in diesel
particulate filter tests, that is to say, reduced filter clogging,
as compared to the use of calcium detergents therein.
[0032] Accordingly, for a given performance in diesel particulate
filter tests, it is now surprisingly possible to use greater
amounts of magnesium detergent in a lubricating oil composition
vis-a-vis a lubricating oil composition comprising calcium
detergent and/or to use a magnesium detergent having a higher TBN
than a calcium detergent in order to meet the basicity requirements
of a lubricating oil composition.
[0033] Thus, the disadvantages associated with trying to achieve a
balance of the basicity properties of a lubricating oil composition
and reducing diesel particulate clogging in a diesel particulate
filter may therefore be overcome by the use of magnesium
detergents.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0034] The present invention provides the use, in a lubricating oil
composition comprising base oil, of one or more magnesium
detergents, for the reduction of clogging in a diesel particulate
filter.
[0035] In particular, the present invention provides the use, in a
lubricating oil composition comprising base oil, of one or more
magnesium detergents, for improving the reduction of clogging in a
diesel particulate filter, especially as compared to the use of
calcium detergents therein.
[0036] Clogging of the diesel particulate filter is preferably
measured using the VW diesel particulate filter test.
[0037] The one or more magnesium detergents used in the present
invention are preferably selected from magnesium salicylate
detergents, magnesium phenate detergents and magnesium sulphonate
detergents. Magnesium salicylate and magnesium phenate detergents
are particularly preferred.
[0038] In order to maintain the total sulphated ash content of the
lubricating oil composition preferably at a level of not greater
than 1.0 wt. %, more preferably at a level of not greater than 0.9
wt. % and most preferably at a level of not greater than 0.8 wt. %,
based on the total weight of the lubricating oil composition, said
one or more magnesium detergents are preferably used in a total
amount of not greater than 0.2 wt. % in terms of magnesium content,
more preferably in a total amount of not greater than 0.17 wt. % in
terms of magnesium content and most preferably in a total amount of
not greater than 0.15 wt. % in terms of magnesium content, based on
the total weight of the lubricating oil composition.
[0039] The magnesium detergents used in the present invention can
be either neutral or overbased. The expression "overbased" is
equivalent to "basic", "superbased", "hyperbased" and "high-metal
containing salts". These magnesium detergents contain an excess
metal content compared to the amount of metal which would be
present according to the stoichiometry of the metal and the acidic
organic compound reacted with the metal. Processes for making such
neutral and basic metal salts are well known in the art. Neutral
salts can be made by heating a mineral oil solution of an acidic
organic compound with a stoichiometric equivalent amount of a metal
neutralizing agent such as the metal oxide, hydroxide, carbonate,
bicarbonate, or sulfide at a temperature above 50.degree. C. and
filtering the resulting mass. Basic salts are made similarly with
the exception that a stoichiometric excess of the metal is used.
Preferably, overbased magnesium detergents are used.
[0040] Detergents can be characterized by their total base number
(TBN). Preferably, the total base numbers of the one or more
magnesium detergents are each, independently, in the range of from
30 to 600 mg.KOH/g, more preferably in the range of from 30 to 450
mg.KOH/g and most preferably in the range of from 30 to 350
mg.KOH/g, as measured by ISO 3771.
[0041] Magnesium salicylates that may be conveniently used may be
either substituted or unsubstituted. Suitable substituents include
aliphatic groups containing from 1 to 40 carbon atoms and
optionally containing one or more oxygen and/or nitrogen atoms, and
hydroxy groups. Preferred substituents are alkyl groups containing
in the range of from 6 to 30 carbon atoms, preferably in the range
of from 12 to 20 carbon atoms. Preferably, the substituents are
linear. The magnesium salicylates may contain in the range of from
1 to 4 substituents, preferably in the range of from 1 to 3, most
preferably 1 or 2 substituents. Most preferably, the magnesium
salicylates may be substituted by 1 linear alkyl group containing
in the range of from 14 to 18 carbon atoms.
[0042] Generally, mono-alkyl salicylic acids are prepared by
alkylation of phenol and subsequent carboxylation. Therefore, a
small amount (generally at most 20% mol) of dialkyl salicylate and
unsubstituted salicylate can be present in the mono-alkyl
salicylate.
[0043] Magnesium salicylates which may be used in the present
invention are commercially available. For example, a commercial
magnesium salicylate is that available under the trade designation
"Infineum C9012" from Infineum.
[0044] A process by which magnesium salicylates can be prepared,
has been described in U.S. Pat. No. 4,627,928.
[0045] EP-A-1195427 describes magnesium phenates and methods of
making such detergents.
[0046] EP-A-1195427, WO-A-97/14774 and U.S. Pat. No. 5,534,168
describe magnesium sulphonate and methods of making overbased
magnesium sulphonates.
[0047] Magnesium phenates and magnesium sulphonates which may be
used in the present invention are commercially available. For
example, a commercial magnesium sulphonate is that available under
the trade designation "Infineum C9340" from Infineum.
[0048] The starting TBN value of the lubricating oil composition
used in the present invention is preferably in the range of from
4.0 to 12.0 mg.KOH/g, more preferably in the range of from 6.0 to
11.0 mg.KOH/g, even more preferably in the range of from 6.0 to
10.0 mg.KOH/g and most preferably in the range of 6.0 to 9.5
mg.KOH/g, as measured by ISO 3771.
[0049] The lubricating oil composition preferably has a sulphated
ash content of not greater than 1.0 wt. %, more preferably not
greater than 0.9 wt. % and most preferably not greater than 0.8 wt.
%, based on the total weight of the lubricating oil
composition.
[0050] The lubricating oil composition preferably has a sulphur
content of not greater than 1.2 wt. %, more preferably not greater
than 0.8 wt. % and most preferably not greater than 0.3 wt. %,
based on the total weight of the lubricating oil composition.
[0051] In the present invention, preferred lubricating oil
compositions have one or more of the following features:
(i) greater than 0.04 wt. % of phosphorus;
(ii) greater than 0.045 wt. % of phosphorus;
(iii) at least 0.04 wt. % of phosphorus;
(iv) less than 0.09 wt. % of phosphorus;
(v) not greater than 0.10 wt. % of phosphorus;
(vi) at most 0.085 wt. % of phosphorus;
(vii) not greater than 1.0 wt. % of sulphated ash;
(viii) not greater than 0.9 wt. % of sulphated ash;
(ix) not greater than 0.8 wt. % of sulphated ash;
(x) not greater than 1.2 wt. % of sulphur;
(xi) not greater than 0.8 wt. % of sulphur; and
(xii) not greater than 0.3 wt. % of sulphur, based on the total
weight of the lubricating oil composition.
[0052] In the present invention, particularly preferred lubricating
oil compositions have one or more of the following features:
[0053] (A): those having features (i) and (iv); those having
features (i) and (v); those having features (i) and (vi); those
having features (ii) and (iv); those having features (ii) and (v);
those having features (ii) and (vi); those having features (iii)
and (iv); those having features (iii) and (v); and those having
features (iii) and (vi);
[0054] (B): those having features (i), (iv) and (vii); those having
features (i), (iv) and (viii); those having features (i), (iv) and
(ix); those having features (i), (v) and (vii); those having
features (i), (v) and (viii); those having features (i), (v) and
(ix); those having features (i), (vi) and (vii); those having
features (i), (vi) and (viii); those having features (i), (vi) and
(ix); those having features (ii), (iv) and (vii); those having
features (ii), (iv) and (viii); those having features (ii), (iv)
and (ix); those having features (ii), (v) and (vii); those having
features (ii), (v) and (viii); those having features (ii), (v) and
(ix); those having features (ii), (vi) and (vii); those having
features (ii), (vi) and (viii); those having features (ii), (vi)
and (ix); those having features (iii), (iv) and (vii); those having
features (iii), (iv) and (viii); those having features (iii), (iv)
and (ix); those having features (iii), (v) and (vii); those having
features (iii), (v) and (viii); those having features (iii), (v)
and (ix); those having features (iii), (vi) and (vii); those having
features (iii), (vi) and (viii); and those having features (iii),
(vi) and (ix);
[0055] (C): those having features (i), (iv) and (x); those having
features (i), (iv) and (xi); those having features (i), (iv) and
(xii); those having features (i), (v) and (x); those having
features (i), (v) and (xi); those having features (i), (v) and
(xii); those having features (i), (vi) and (x); those having
features (i), (vi) and (xi); those having features (i), (vi) and
(xii); those having features (ii), (iv) and (x); those having
features (ii), (iv) and (xi); those having features (ii), (iv) and
(xii); those having features (ii), (v) and (x); those having
features (ii), (v) and (xi); those having features (ii), (v) and
(xii); those having features (ii), (vi) and (x); those having
features (ii), (vi) and (xi); those having features (ii), (vi) and
(xii); those having features (iii), (iv) and (x); those having
features (iii), (iv) and (xi); those having features (iii), (iv)
and (xii); those having features (iii), (v) and (x); those having
features (iii), (v) and (xi); those having features (iii), (v) and
(xii); those having features (iii), (vi) and (x); those having
features (iii), (vi) and (xi); and those having features (iii),
(vi) and (xii); and
[0056] (D): those having features (i), (iv), (vii) and (x); those
having features (i), (iv), (viii) and (x); those having features
(i), (iv), (ix) and (x); those having features (i), (v), (vii) and
(x); those having features (i), (v), (viii) and (x); those having
features (i), (v), (ix) and (x); those having features (i), (vi),
(vii) and (x); those having features (i), (vi), (viii) and (x);
those having features (i), (vi), (ix) and (x); those having
features (ii), (iv), (vii) and (x); those having features (ii),
(iv), (viii) and (x); those having features (ii), (iv), (ix) and
(x); those having features (ii), (v), (vii) and (x); those having
features (ii), (v), (viii) and (x); those having features (ii),
(v), (ix) and (x); those having features (ii), (vi), (vii) and (x);
those having features (ii), (vi), (viii) and (x); those having
features (ii), (vi), (ix) and (x); those having features (iii),
(iv), (vii) and (x); those having features (iii), (iv), (viii) and
(x); those having features (iii), (iv), (ix) and (x); those having
features (iii), (v), (vii) and (x); those having features (iii),
(v), (viii) and (x); those having features (iii), (v), (ix) and
(x); those having features (iii), (vi), (vii) and (x); those having
features (iii), (vi), (viii) and (x); those having features (iii),
(vi), (ix) and (x); those having features (i), (iv), (vii) and
(xi); those having features (i), (iv), (viii) and (xi); those
having features (i), (iv), (ix) and (xi); those having features
(i), (v), (vii) and (xi); those having features (i), (v), (viii)
and (xi); those having features (i), (v), (ix) and (xi); those
having features (i), (vi), (vii) and (xi); those having features
(i), (vi), (viii) and (xi); those having features (i), (vi), (ix)
and (xi); those having features (ii), (iv), (vii) and (xi); those
having features (ii), (iv), (viii) and (xi); those having features
(ii), (iv), (ix) and (xi); those having features (ii), (v), (vii)
and (xi); those having features (ii), (v), (viii) and (xi); those
having features (ii), (v), (ix) and (xi); those having features
(ii), (vi), (vii) and (xi); those having features (ii), (vi),
(viii) and (xi); those having features (ii), (vi), (ix) and (xi);
those having features (iii), (iv), (vii) and (xi); those having
features (iii), (iv), (viii) and (xi); those having features (iii),
(iv), (ix) and (xi); those having features (iii), (v), (vii) and
(xi); those having features (iii), (v), (viii) and (xi); those
having features (iii), (v), (ix) and (xi); those having features
(iii), (vi), (vii) and (xi); those having features (iii), (vi),
(viii) and (xi); those having features (iii), (vi), (ix) and (xi);
those having features (i), (iv), (vii) and (xii); those having
features (i), (iv), (viii) and (xii); those having features (i),
(iv), (ix) and (xii); those having features (i), (v), (vii) and
(xii); those having features (i), (v), (viii) and (xii); those
having features (i), (v), (ix) and (xii); those having features
(i), (vi), (vii) and (xii); those having features (i), (vi), (viii)
and (xii); those having features (i), (vi), (ix) and (xii); those
having features (ii), (iv), (vii) and (xii); those having features
(ii), (iv), (viii) and (xii); those having features (ii), (iv),
(ix) and (xii); those having features (ii), (v), (vii) and (xii);
those having features (ii), (v), (viii) and (xii); those having
features (ii), (v), (ix) and (xii); those having features (ii),
(vi), (vii) and (xii); those having features (ii), (vi), (viii) and
(xii); those having features (ii), (vi), (ix) and (xii); those
having features (iii), (iv), (vii) and (xii); those having features
(iii), (iv), (viii) and (xii); those having features (iii), (iv),
(ix) and (xii); those having features (iii), (v), (vii) and (xii);
those having features (iii), (v), (viii) and (xii); those having
features (iii), (v), (ix) and (xii); those having features (iii),
(vi), (vii) and (xii); those having features (iii), (vi), (viii)
and (xii); and those having features (iii), (vi), (ix) and
(xii).
[0057] The amount of base oil incorporated in the lubricating oil
composition is preferably present in an amount in the range of from
60 to 92 wt. %, more preferably in an amount in the range of from
75 to 90 wt. % and most preferably in an amount in the range of
from 75 to 88 wt. %, with respect to the total weight of the
lubricating oil composition.
[0058] There are no particular limitations regarding the base oil
used in the present invention, and various conventional known
mineral oils and synthetic lubricating oils may be conveniently
used.
[0059] Mineral oils include liquid petroleum oils and
solvent-treated or acid-treated mineral lubricating oil of the
paraffinic, naphthenic, or mixed paraffinic/naphthenic type which
may be further refined by hydrofinishing processes and/or
dewaxing.
[0060] Naphthenic base oils have low viscosity index (VI)
(generally 40-80) and a low pour point. Such base oils are produced
from feedstocks rich in naphthenes and low in wax content and are
used mainly for lubricants in which colour and colour stability are
important, and VI and oxidation stability are of secondary
importance.
[0061] Paraffinic base oils have higher VI (generally >95) and a
high pour point. Said base oils are produced from feedstocks rich
in paraffins, and are used for lubricants in which VI and oxidation
stability are important.
[0062] Fischer-Tropsch derived base oils may be conveniently used
as the base oil in the lubricating oil composition of the present
invention, for example, the Fischer-Tropsch derived base oils
disclosed in EP-A-776959, EP-A-668342, WO-A-97/21788, WO-00/15736,
WO-00/14188, WO-00/14187, WO-00/14183, WO-00/14179, WO-00/08115,
WO-99/41332, EP-1029029, WO-01/18156 and WO-01/57166.
[0063] Synthetic processes enable molecules to be built from
simpler substances or to have their structures modified to give the
precise properties required.
[0064] Synthetic base oils include hydrocarbon oils such as olefin
oligomers (PAOs), dibasic acids esters, polyol esters, and dewaxed
waxy raffinate. Synthetic hydrocarbon base oils sold by the Shell
group under the designation "XHVI" (trade mark) may be conveniently
used.
[0065] Preferably, the base oil is constituted from mineral oils
and/or synthetic base oils which contain more than 80% wt of
saturates, preferably more than 90% wt., as measured according to
ASTM D2007.
[0066] It is further preferred that the base oil contains less than
1.0 wt. %, preferably less than 0.1 wt. % of sulphur, calculated as
elemental sulphur and measured according to ASTM D2622, ASTM D4294,
ASTM D4927 or ASTM D3120.
[0067] Preferably, the viscosity index of the base oil is more than
80, more preferably more than 120, as measured according to ASTM
D2270.
[0068] Preferably, the lubricating oil composition has a kinematic
viscosity in the range of from 2 to 80 mm.sup.2/s at 100.degree.
C., more preferably of from 3 to 70 mm.sup.2/s, most preferably of
from 4 to 50 mm.sup.2/s.
[0069] In the present invention, the lubricating oil composition
may optionally further comprise one or more additional additives
such as anti-oxidants, anti-wear additives, supplementary
detergents, dispersants, friction modifiers, viscosity index
improvers, pour point depressants, corrosion inhibitors, defoaming
agents and seal fix or seal compatibility agents.
[0070] In one embodiment of the present invention, the lubricating
oil composition may comprise one or more aminic and/or phenolic
antioxidants.
[0071] Examples of aminic antioxidants which may be conveniently
used include alkylated diphenylamines,
phenyl-.alpha.-naphthylamines, phenyl-.beta.-naphthylamines and
alkylated .alpha.-naphthylamines.
[0072] Preferred aminic antioxidants include dialkyldiphenylamines
such as p,p'-dioctyl-diphenylamine,
p,p'-di-.alpha.-methylbenzyl-diphenylamine and
N-p-butylphenyl-N-p'-octylphenylamine, monoalkyldiphenylamines such
as mono-t-butyldiphenylamine and mono-octyldiphenylamine,
bis(dialkylphenyl)amines such as di-(2,4-diethylphenyl)amine and
di(2-ethyl-4-nonylphenyl)amine, alkylphenyl-1-naphthylamines such
as octylphenyl-1-naphthylamine and
n-t-dodecylphenyl-1-naphthylamine, 1-naphthylamine,
arylnaphthylamines such as phenyl-1-naphthylamine,
phenyl-2-naphthylamine, N-hexylphenyl-2-naphthylamine and
N-octylphenyl-2-naphthylamine, phenylenediamines such as
N,N'-diisopropyl-p-phenylenediamine and
N,N'-diphenyl-p-phenylenediamine, and phenothiazines such as
phenothiazine and 3,7-dioctylphenothiazine.
[0073] Preferred aminic antioxidants include those available under
the following trade designations: "Sonoflex OD-3" (ex. Seiko Kagaku
Co.), "Irganox L-57" (ex. Ciba Specialty Chemicals Co.) and
phenothiazine (ex. Hodogaya Kagaku Co.).
[0074] Examples of phenolic antioxidants which may be conveniently
used include C.sub.7-C.sub.9 branched alkyl esters of
3,5-bis(1,1-dimethyl-ethyl)-4-hydroxy-benzenepropanoic acid,
2-t-butylphenol, 2-t-butyl-4-methylphenol,
2-t-butyl-5-methylphenol, 2,4-di-t-butylphenol,
2,4-dimethyl-6-t-butylphenol, 2-t-butyl-4-methoxyphenol,
3-t-butyl-4-methoxyphenol, 2,5-di-t-butylhydroquinone,
2,6-di-t-butyl-4-alkylphenols such as 2,6-di-t-butylphenol,
2,6-di-t-butyl-4-methylphenol and 2,6-di-t-butyl-4-ethylphenol,
2,6-di-t-butyl-4-alkoxyphenols such as
2,6-di-t-butyl-4-methoxyphenol and 2,6-di-t-butyl-4-ethoxyphenol,
3,5-di-t-butyl-4-hydroxybenzylmercaptooctylacetate,
alkyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionates such as
n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,
n-butyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and
2'-ethylhexyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,
2,6-d-t-butyl-.alpha.-dimethylamino-p-cresol,
2,2'-methylenebis(4-alkyl-6-t-butylphenol) such as
2,2'-methylenebis(4-methyl-6-t-butylphenol, and
2,2-methylenebis(4-ethyl-6-t-butylphenol), bisphenols such as
4,4'-butylidenebis(3-methyl-6-t-butylphenol,
4,4'-methylenebis(2,6-di-t-butylphenol),
4,4'-bis(2,6-di-t-butylphenol), 2,2-(di-p-hydroxyphenyl)propane,
2,2-bis(3,5-di-t-butyl-4-hydroxyphenyl)propane,
4,4'-cyclohexylidenebis(2,6-t-butylphenol),
hexamethyleneglycol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],
triethyleneglycolbis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate],
2,2'-thio-[diethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],
3,9-bis{1,1-dimethyl-2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionylo-
xy]ethyl}2,4,8,10-tetraoxaspiro[5,5]undecane,
4,4'-thiobis(3-methyl-6-t-butylphenol) and
2,2'-thiobis(4,6-di-t-butylresorcinol), polyphenols such as
tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane,
1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane,
1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,
bis-[3,3'-bis(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol
ester,
2-(3',5'-di-t-butyl-4-hydroxyphenyl)methyl-4-(2'',4''-di-t-butyl-3''-hydr-
oxyphenyl)methyl-6-t-butylphenol and
2,6-bis(2'-hydroxy-3'-t-butyl-5'-methylbenzyl)-4-methylphenol, and
p-t-butylphenol-formaldehyde condensates and
p-t-butylphenol-acetaldehyde condensates.
[0075] Preferred phenolic antioxidants include those available
under the following trade designations: "Irganox L-135" (ex. Ciba
Specialty Chemicals Co.), "Anteeji DBH" (ex. Kawaguchi Kagaku
Co.,), "Yoshinox SS" (ex. Yoshitomi Seiyaku Co.), "Antage W-400"
(ex. Kawaguchi Kagaku Co.), "Antage W-500" (ex. Kawaguchi Kagaku
Co.), "Antage W-300" (ex. Kawaguchi Kagaku Co.), "Ionox 220AH" (ex.
Shell Japan Co.), bisphenol A, produced by the Shell Japan Co.,
"Irganox L109" (ex. Ciba Specialty Chemicals Co.), "Tominox 917"
(ex. Yoshitomi Seiyaku Co.), "Irganox L115" (ex. Ciba Specialty
Chemicals Co.), "Sumilizer GA80" (ex. Sumitomo Kagaku), "Antage RC"
(ex. Kawaguchi Kagaku Co.), "Irganox L101" (ex. Ciba Speciality
Chemicals Co.), "Yoshinox 930" (ex. Yoshitomi Seiyaku Co.), "Ionox
330" (ex. Shell Japan Co.).
[0076] The lubricating oil composition may comprise mixtures of one
or more phenolic antioxidants with one or more aminic
antioxidants.
[0077] In a preferred embodiment of the present invention, the
lubricating oil composition may comprise one or more anti-wear
additives.
[0078] Anti-wear additives that may be conveniently used include
molybdenum-containing compounds, boron-containing compounds and
zinc-containing compounds.
[0079] Examples of such molybdenum-containing compounds may
conveniently include molybdenum dithiocarbamates, trinuclear
molybdenum compounds, for example as described in WO-A-98/26030,
sulphides of molybdenum and molybdenum dithiophosphate.
[0080] Said molybdenum-containing anti-wear additives may be
conveniently added to the lubricating oil composition in an amount
in the range of from 0.1 to 3.0 wt. %, based on the total weight of
lubricating oil composition.
[0081] Boron-containing compounds that may be conveniently used
include borate esters, borated fatty amines, borated epoxides,
alkali metal (or mixed alkali metal or alkaline earth metal)
borates and borated overbased metal salts.
[0082] Said boron-containing anti-wear additives may be
conveniently added to the lubricating oil composition in an amount
in the range of from 0.1 to 3.0 wt. %, based on the total weight of
lubricating oil composition.
[0083] Preferred zinc-containing anti-wear additives are one or
more zinc dithiophosphates selected from zinc dialkyl-, diaryl- or
alkylaryl-dithiophosphates.
[0084] Zinc dithiophosphate is a well known additive in the art and
may be conveniently represented by general formula II; ##STR1##
wherein R.sup.2 to R.sup.5 may be the same or different and are
each a primary alkyl group containing from 1 to 20 carbon atoms
preferably from 3 to 12 carbon atoms, a secondary alkyl group
containing from 3 to 20 carbon atoms, preferably from 3 to 12
carbon atoms, an aryl group or an aryl group substituted with an
alkyl group, said alkyl substituent containing from 1 to 20 carbon
atoms preferably 3 to 18 carbon atoms.
[0085] Zinc dithiophosphate compounds in which R.sup.2 to R.sup.5
are all different from each other can be used alone or in admixture
with zinc dithiophosphate compounds in which R.sup.2 to R.sup.5 are
all the same.
[0086] Preferably, the or each zinc dithiophosphate used in the
present invention is a zinc dialkyl dithiophosphate.
[0087] Examples of suitable zinc dithiophosphates which are
commercially available include those available ex. Lubrizol
Corporation under the trade designations "Lz 1097" and "Lz 1395",
those available ex. Chevron Oronite under the trade designations
"OLOA 267" and "OLOA 269R", and that available ex. Ethyl under the
trade designation "HITEC 7197"; zinc dithiophosphates such as those
available ex. Lubrizol Corporation under the trade designations "Lz
677A", "Lz 1095" and "Lz 1371", that available ex. Chevron Oronite
under the trade designation "OLOA 262" and that available ex. Ethyl
under the trade designation "HITEC 7169"; and zinc dithiophosphates
such as those available ex. Lubrizol Corporation under the trade
designations "Lz 1370" and "Lz 1373" and that available ex. Chevron
Oronite under the trade designation "OLOA 260".
[0088] The lubricating oil composition may preferably comprise in
the range of from 0.4 to 1.0 wt. % of zinc dithiophosphate, more
preferably in the range of from 0.4 to 0.9 wt. % and most
preferably in the range of from 0.45 to 0.8 wt. %, based on total
weight of the lubricating oil composition.
[0089] The total amount of phosphorus in the lubricating oil
composition is preferably in the range of from 0.04 to 0.1 wt. %,
more preferably in the range of from 0.04 to 0.09 wt. % and most
preferably in the range of from 0.045 to 0.085 wt. %, based on
total weight of the lubricating oil composition.
[0090] Supplementary detergents that may be conveniently used in
the lubricating oil composition include one or more calcium
detergents selected from calcium salicylates, calcium phenates and
calcium sulphonates.
[0091] The calcium detergents can be either neutral or overbased.
Preferably, the total base number of said calcium detergents is in
the range of from 30 to 600 mg.KOH/g, more preferably in the range
of from 30 to 450 mg.KOH/g, most preferably in the range of from 30
to 350 mg.KOH/g, as measured by ISO 3771.
[0092] Examples of commercial calcium detergents include the
calcium salicylates which are available from Infineum under the
trade designations "Infineum M7101", "Infineum M7102" and "Infineum
M 7105".
[0093] In order that said calcium detergents do not adversely
affect the diesel particulate filters of internal combustion
engines, it is preferred that said one or more calcium detergents
are used in a total amount of no greater than 0.12 wt. % in terms
of calcium content, more preferably in a total amount of no greater
than 0.08 wt. % in terms of calcium content and most preferably in
a total amount of no greater than 0.05 wt. % in terms of calcium
content, based on the total weight of the lubricating oil
composition.
[0094] The lubricating oil composition may comprise an ash-free
dispersant which is preferably admixed in an amount in the range of
from 5 to 15 wt. %, based on the total weight of the lubricating
oil composition.
[0095] Examples of dispersants which may be used include the
polyalkenyl succinimides and polyalkenyl succininic acid esters
disclosed in Japanese Patent Nos. 1367796, 1667140, 1302811 and
1743435. Preferred dispersants include borated succinimides.
[0096] Preferred friction modifiers that may be conveniently used
include fatty acid esters and fatty acid amides.
[0097] The total amount of friction modifiers added to the
lubricating oil composition in conveniently in the range of from
0.05 to 2.0 wt. %, based on the total weight of the lubricating oil
composition.
[0098] Examples of viscosity index improvers which may conveniently
used in the lubricating oil composition include the
styrene-butadiene copolymers, styrene-isoprene stellate copolymers
and the polymethacrylate-based and ethylene-propylene copolymers
and the like disclosed in Japanese Patent Nos. 954077, 1031507,
1468752, 1764494 and 1751082. Such viscosity index improvers may be
conveniently employed in an amount in the range of from 1 to 20 wt.
%, based on the total weight of the lubricating oil composition.
Similarly, dispersing-type viscosity index improvers comprising
copolymerized polar monomer containing nitrogen atoms and oxygen
atoms in the molecule may also be used therein.
[0099] Polymethacrylates such as those as disclosed in Japanese
Patent Nos. 1195542 and 1264056 may be conveniently employed in the
lubricating oil compositions of the present invention as effective
pour point depressants.
[0100] Furthermore, compounds such as alkenyl succinic acid or
ester moieties thereof, benzotriazole-based compounds and
thiodiazole-based compounds may be conveniently used in the
lubricating oil composition as corrosion inhibitors.
[0101] Compounds such as polysiloxanes, dimethyl polycyclohexane
and polyacrylates may be conveniently used in the lubricating oil
composition as defoaming agents.
[0102] Compounds which may be conveniently used in the lubricating
oil composition as seal fix or seal compatibility agents include,
for example, commercially available aromatic esters.
[0103] The lubricating oil composition as herein before described
may be conveniently prepared by admixing the one or more magnesium
detergents, and, optionally, one or more additional additives, for
example as herein before described, with base oil.
[0104] In the present invention, lubricating oil compositions
comprising one or more magnesium detergents and base oil have been
surprisingly found to give advantageous performance in diesel
particulate filter tests, in particular in the VW diesel
particulate filter test.
[0105] In a preferred embodiment of the present invention, the use
of said lubricating oil compositions gives a result of less than
50% weight increase of a diesel particulate filter, as measured by
the VW diesel particulate filter test.
[0106] In another embodiment of the present invention, there is
provided a method of improving performance in a diesel particulate
filter test, in particular in the VW diesel particulate filter
test, said method comprising lubricating an internal combustion
engine with a lubricating oil composition as hereinbefore described
comprising one or more magnesium detergents and base oil.
[0107] The present invention is described below with reference to
the following Examples, which are not intended to limit the scope
of the invention in any way.
EXAMPLES
Formulations
[0108] Table 1 indicates the formulations that were tested.
[0109] The formulations in Table 1 comprised conventional
antioxidants, anti-foams, dispersants, friction modifiers, seals
fix additives, pour point depressants, viscosity index modifiers
and zinc dithiophosphate additives.
[0110] The magnesium detergent used was that available under the
trade designation "Infineum C9012" (TBN 345 mg.KOH/g) from
Infineum.
[0111] The calcium detergents used were those available under the
trade designations "Infineum M7101" (TBN 168 mg.KOH/g), "Infineum
M7102" (TBN 64 mg.KOH/g) and "Infineum M7105" (TBN 280 mg.KOH/g)
from Infineum.
[0112] The base oils used in said formulations were Group III base
oils available from the Shell group under the trade designations
"XHVI-5.2" and "XHVI-8.2".
[0113] All formulations described in Table 1 were SAE 5W30
viscosity grade oils. TABLE-US-00001 TABLE 1 Comp. Comp. Additive
(wt. %) Ex. 1 Ex. 2 Ex. 1 Ex. 2 Anti-foam 30 ppm 30 ppm 30 ppm 30
ppm Calcium salicylate.sup.1 -- -- 0.80 1.20 Calcium
salicylate.sup.2 -- 1.00 -- -- Calcium saliylate.sup.3 -- -- 1.60
1.00 Magnesium 2.20 1.20 -- -- salicylate.sup.4 Phenolic 4.00 4.00
4.00 4.00 antioxidant.sup.5 PIB succinimide 8.00 8.00 8.00 8.00
dispersant Zinc 0.50 0.80 0.50 0.60 dithiophosphates Viscosity
modifiers 11.50 8.70 12.00 12.00 Other additives.sup.6 -- 0.70 --
2.50 Base Oil.sup.7 73.80 75.60 73.10 70.70 TOTAL 100 100 100 100
.sup.1TBN 168 mg.KOH/g. Available from Infineum under the trade
designation "Infineum M7101". .sup.2TBN 64 mg.KOH/g. Available from
Infineum under the trade designation "Infineum M7102". .sup.3TBN
280 mg.KOH/g. Available from Infineum under the trade designation
"Infineum M7105". .sup.4TBN 345 mg.KOH/g. Available from Infineum
under the trade designation "Infineum C9012". .sup.5Antioxidant
available under the trade designation "IRGANOX L-135" from Ciba
Specialty Chemicals. .sup.6Mixture of conventional additives
selected from pour point depressant, friction modifier, corrosion
inhibitor and seal fix additives. .sup.7Group III base oil mixtures
of XHVI-5.2 and XHVI-8.2 except for Comp. Ex. 2 which used only
XHVI-5.2.
VW Diesel Particulate Filter (DPF) Test
[0114] The VW diesel particulate filter (DPF) test forms part of
the VW factory fill specification 52195.
[0115] The experimental methodology used to obtain the results of
Table 2 was in accordance with the publicly available test that is
carried out on a commercial basis by an independent lubricant test
laboratory, ISP.
[0116] The VW diesel particulate filter test measures the
percentage weight increase of a diesel particulate filter after a
450 hour engine test.
[0117] The publicly available test quotes results with respect to a
percentage weight increase against the weight increase of the
diesel particulate filter using a standard test reference oil.
[0118] The test limit for a VW pass is set at <50% weight
increase against this reference oil.
Results and Discussion
[0119] The formulations described in Table 1 were tested using the
afore-mentioned test and the results obtained thereon are included
in Table 2.
[0120] It is apparent from Table 2 that for a given sulphated ash
level, the use of magnesium detergent vis-a-vis calcium detergents
surprisingly gives improved performance in the VW diesel
particulate filter test to the extent that the lubricating oil
composition of Example 1 is much lower than the VW test limit
whereas the comparable lubricating oil composition of Comparative
Example 1 exceeds the VW test limit.
[0121] Example 2 demonstrates that the use of magnesium detergent
in combination with calcium detergent gives rise to a lubricating
oil composition which is lower than the VW test limit.
TABLE-US-00002 TABLE 2 Comp. Comp. Results Ex. 1 Ex. 2 Ex. 1 Ex. 2
Soap (mmol/kg) 9.0 9.0 9.0 9.1 Starting Total Base 9.50 6.40 7.70
6.70 Number (TBN) (mg.KOH/g) Total Sulphated ash 0.80 0.61 0.80
0.70 (wt. %)(ASTM D874) Total Sulphur <0.3 0.21 <0.3 <0.3
(wt. %)(ASTM D2622) Total Phosphorus 0.049 0.083 0.047 0.059 (wt.
%)(ICP-OES method) Ca (wt. %) (ICP-OES -- 0.025 0.207 0.167 method)
Mg (wt. %) (ICP-OES 0.163 0.083 -- -- method) Starting Kinematic
12.09 12.21 12.10 12.20 Viscosity (100.degree. C.) (mm.sup.2/s)
Starting Kinematic 69.50 70.05 69.45 68.16 Viscosity (40.degree.
C.) (mm.sup.2/s) Cold Cranking Shear 64.03 62.58 63.78 59.25
(CCS)Viscosity (-30.degree. C.) (P)(Pa s) % Weight Increase 40.00
42.19 63.96 57.80 of Diesel Particulate Filter (VW Diesel
Particulate Test)
* * * * *