U.S. patent application number 10/788734 was filed with the patent office on 2005-09-01 for lubricant compositions for providing anti-shudder performance and elastomeric component compatibility.
Invention is credited to Iyer, Ramnath N., Tersigni, Samuel H..
Application Number | 20050192186 10/788734 |
Document ID | / |
Family ID | 34750538 |
Filed Date | 2005-09-01 |
United States Patent
Application |
20050192186 |
Kind Code |
A1 |
Iyer, Ramnath N. ; et
al. |
September 1, 2005 |
Lubricant compositions for providing anti-shudder performance and
elastomeric component compatibility
Abstract
Compositions and methods are disclosed for providing
anti-shudder performance in power transmission fluids through the
incorporation of a non-dispersant viscosity index improver.
Further, the disclosed compositions achieve improved compatibility
of an elastomeric component with a lubricating fluid through the
incorporation of a non-dispersant viscosity index improver.
Inventors: |
Iyer, Ramnath N.; (Glen
Allen, VA) ; Tersigni, Samuel H.; (Glen Allen,
VA) |
Correspondence
Address: |
DENNIS H. RAINEAR
CHIEF PATENT COUNSEL, ETHYL CORPORATION
330 SOUTH FOURTH STREET
RICHMOND
VA
23219
US
|
Family ID: |
34750538 |
Appl. No.: |
10/788734 |
Filed: |
February 27, 2004 |
Current U.S.
Class: |
508/469 |
Current CPC
Class: |
C10M 2227/081 20130101;
C10M 2205/04 20130101; C10M 2209/084 20130101; C10M 2205/06
20130101; C10M 2217/022 20130101; C10N 2020/02 20130101; C10M
2205/02 20130101; C10M 145/14 20130101; C10N 2030/02 20130101 |
Class at
Publication: |
508/469 |
International
Class: |
C10M 145/14 |
Claims
What is claimed is:
1. A power transmitting fluid for use in a power transmitting
device, comprising: (a) a major amount of a base oil; and (b) a
minor amount of an additive composition comprising at least one
non-dispersant viscosity index improver, wherein the power
transmitting fluid provides anti-shudder performance to the power
transmitting device.
2. The fluid of claim 1, wherein the non-dispersant viscosity index
improver comprises a polymethacrylate viscosity index improver.
3. The fluid of claim 1, wherein the non-dispersant viscosity index
improver is present in an amount from about 0.01 wt % to about 50
wt % in the additive composition.
4. The fluid of claim 3, wherein the non-dispersant viscosity index
improver is present in an amount from about 1 wt % to about 25 wt %
in the additive composition.
5. The fluid of claim 4, wherein the non-dispersant viscosity index
improver is present in an amount from about 3 wt % to about 15 wt %
in the additive composition.
6. The fluid of claim 1, wherein the base oil comprises one or more
of a natural lubricating oil, a synthetic lubricating oil, and a
mixture thereof.
7. The fluid of claim 1, wherein the fluid is free of a dispersant
viscosity index improver.
8. The fluid of claim 1, wherein the fluid is suitable for use in
an automatic transmission, a continuously variable transmission, a
slipping torque converter, a step automatic transmission, a
clutch-to-clutch transmission, and a transmission with a wet
starting clutch.
9. The fluid of claim 1, wherein the power transmitting fluid
provides improved anti-shudder performance relative to a power
transmitting fluid free of at least one non-dispersant viscosity
index improver and containing a dispersant viscosity index
improver.
10. An automatic transmission lubricated with the fluid of claim
1.
11. The automatic transmission of claim 10, wherein the
transmission is a continuously variable transmission.
12. A lubricating fluid having compatibility with an elastomeric
component, comprising: (a) a major amount of a base oil; and (b) a
minor amount of an additive composition having at least one
non-dispersant viscosity index improver.
13. The fluid of claim 12, wherein the fluid further promotes
swelling of the elastomeric component.
14. The fluid of claim 12, wherein the non-dispersant viscosity
index improver comprises a polymethacrylate viscosity index
improver.
15. The fluid of claim 12, wherein the non-dispersant viscosity
index improver is present in an amount from about 0.01 wt % to
about 50 wt % in the additive composition.
16. The fluid of claim 15, wherein the non-dispersant viscosity
index improver is present in an amount from about 1 wt % to about
25 wt % in the additive composition.
17. The fluid of claim 16, wherein the non-dispersant viscosity
index improver is present in an amount from about 3 wt % to about
15 wt % in the additive composition.
18. The fluid of claim 12, wherein the base oil comprises one or
more of a natural lubricating oil, a synthetic lubricating oil, and
a mixture thereof.
19. The seals and/or hoses of claim 12, wherein the elastomeric
component includes one or more of a seal, a hose, a gasket, and a
belt.
20. The seals and/or hoses of claim 12, wherein the elastomeric
component is composed of any one of a chlorinated polyethylene, a
nitrile rubber, a polyacrylate, a fluoroelastomer, and a
silicone.
21. The fluid of claim 12, wherein the fluid is suitable for use in
an automatic transmission, a continuously variable transmission
(CVT), a slipping torque converter, a step automatic transmission,
a clutch-to-clutch transmission, and a transmissions with a wet
starting clutch.
22. The fluid of claim 12, wherein the compatibility is improved
relative to a fluid free of a non-dispersant viscosity index
improver.
23. The fluid of claim 12, wherein the compatibility is improved
relative to a fluid free of a non-dispersant viscosity index
improver and containing a dispersant viscosity index improver.
24. The fluid of claim 12, wherein the fluid is free of a
dispersant viscosity index improver.
25. The fluid of claim 12, wherein the fluid further contains a
seal swell agent.
26. A method of lubricating a power transmission, comprising adding
to, and operating in, a power transmission having an elastomeric
component a fluid as set forth in claim 12.
27. An automatic transmission lubricated with the fluid of claim
12.
28. The automatic transmission of claim 27 wherein the transmission
is a continuously variable transmission.
29. A method of improving the anti-shudder capabilities of a power
transmission fluid, comprising: lubricating a power transmission
with a power transmission fluid comprising: (a) a major amount of a
base oil; and (b) a minor amount of an additive composition
comprising at least one non-dispersant viscosity index
improver.
30. A method of improving the torque performance of a power
transmission fluid, comprising: lubricating a power transmission
with a power transmission fluid comprising: (a) a major amount of a
base oil; and (b) a minor amount of an additive composition
comprising at least one non-dispersant viscosity index
improver.
31. A method of improving the compatibility of a lubricating fluid
with an elastomeric component, said method comprising lubricating
an elastomeric component with a fluid comprising: (a) a major
amount of a base oil; and (b) a minor amount of an additive
composition comprising at least one non-dispersant viscosity index
improver.
32. The method of claim 31, wherein the elastomeric component
comprises one or more of a seal, a hose, a gasket, and a belt.
33. The method of claim 31, wherein the elastomeric material is
composed of one of a chlorinated polyethylene, a nitrile rubber, a
polyacrylate, a silicone, and a fluoroelastomer.
34. A method of promoting seal swell of an elastomeric seal,
comprising lubricating the elastomeric seal with a lubricating
fluid comprising: (a) a major amount of a base oil; and (b) a minor
amount of an additive composition comprising at least one
non-dispersant viscosity index improver.
35. A method of making a power transmitting fluid having
anti-shudder capabilities, comprising adding to a major amount of a
base oil a minor amount of an additive composition having a
non-dispersant viscosity index improver.
36. A method of making a lubricating fluid having improved
compatibility with an elasotmeric component, comprising adding to a
major amount of a base oil a minor amount of an additive
composition having a non-dispersant viscosity index improver.
Description
FIELD
[0001] The present disclosure relates to lubricant compositions and
methods utilizing the lubricant compositions to provide and/or
improve anti-shudder capabilities of automotive transmission
fluids. The present disclosure also provides lubricant compositions
that provide and/or improve compatibility with elastomeric
components.
BACKGROUND
[0002] New and advanced transmission systems are being developed by
the automotive industry. These new systems often involve high
energy requirements. Therefore, friction materials technology must
be developed to meet the increasing energy requirements of these
advanced fluid systems.
[0003] The high speeds generated during engagement and
disengagement of some of the newer transmission systems mean that a
friction system must be able to maintain a relatively constant
friction throughout the engagement. It is important that the
frictional engagement be relatively constant over a wide range of
speeds and temperatures in order to minimize "shuddering" of
materials during transmission power shift from one gear to
another.
[0004] In particular, new high energy type friction materials are
being developed and used. The new high energy friction materials
are able to withstand high speeds wherein internal transmission
plate surface speeds are up to about 65 m/second. It is also
important that the friction material be useful under limited
lubrication conditions. One such material being developed for
automatic transmission applications is a carbon fiber containing
material.
[0005] In view of new materials and greater demands on
transmissions, automotive power transmission fluids are called upon
to provide specific frictional properties under very demanding
conditions of speed, temperature, and pressure. Changes in a
fluid's frictional properties as a function of relative sliding
speed, temperature, or pressure may cause performance degradation
immediately noticeable to the vehicle operator. Such effects may
include unacceptably long or short gear shifts, vehicle shudder or
vibration, noise, and/or harsh shifts ("gear change shock"). Thus,
there is a need for transmission fluids that exhibit improved
characteristics such as shear and friction stability at high
temperatures and pressures. Such fluids would reduce equipment and
performance problems while improving the interval between fluid
changes. By enabling smooth engagement of torque converter and
shifting clutches, these fluids may reduce shudder, vibration,
and/or noise, and in some cases improve fuel economy, over a longer
fluid lifetime.
[0006] Friction modifiers are used in transmission fluids to
control friction between surfaces (e.g., the members of a torque
converter clutch or a shifting clutch) at low sliding speeds. The
result is a friction vs. velocity (u-v) curve that has a positive
slope, which in turn leads to smooth clutch engagements and
minimizes "stick-slip" behavior (e.g., shudder, noise, and harsh
shifts). Many conventional friction modifiers, however, are
thermally unstable. Upon prolonged exposure to heat, these
additives decompose, and the benefits they confer on clutch
performance may be lost.
[0007] In addition, deterioration of structural elastomeric
elements or components such as seals, belts, gaskets, bushings,
filters, and/or hoses in engines, transmissions, gears, and/or
axles may occur. Such deterioration may be attributed to
interactions between the elastomeric material of said elements and
the reactive or deteriorative components of a lubricant composition
or fluid. Further, a lubricating fluid should provide appropriate
swelling of seals, gaskets, and the like. It is additionally an
object of the compositions and methods of the present invention to
reduce the deterioration of, improve the compatibility with, and
promote proper swell of such seals, hoses, and like elements and
components.
SUMMARY OF EMBODIMENTS
[0008] In an embodiment, a power transmitting fluid for use in a
power transmitting device may comprising a major amount of a base
oil and a minor amount of an additive composition. The additive
composition may comprise at least one non-dispersant viscosity
index improver, wherein the power transmitting fluid provides
anti-shudder performance to the power transmitting device.
[0009] In another embodiment, a lubricating fluid having
compatibility with an elastomeric component may comprise a major
amount of a base oil and a minor amount of an additive composition
having at least one non-dispersant viscosity index improver.
[0010] In another embodiment, a method of improving the
anti-shudder capabilities of a power transmission fluid may
comprise lubricating a power transmission with a power transmission
fluid comprising a major amount of a base oil and a minor amount of
an additive composition comprising at least one non-dispersant
viscosity index improver.
[0011] In another embodiment, a method of improving the torque
performance of a power transmission fluid may comprise lubricating
a power transmission with a power transmission fluid comprising a
major amount of a base oil and a minor amount of an additive
composition comprising at least one non-dispersant viscosity index
improver.
[0012] In another embodiment, a method of improving the
compatibility of a lubricating fluid with an elastomeric component
may comprise lubricating an elastomeric component with a fluid
comprising a major amount of a base oil and a minor amount of an
additive composition comprising at least one non-dispersant
viscosity index improver.
[0013] In another embodiment, a method of promoting seal swell of
an elastomeric seal may comprise lubricating the elastomeric seal
with a lubricating fluid comprising a major amount of a base oil
and a minor amount of an additive composition comprising at least
one non-dispersant viscosity index improver.
[0014] In another embodiment, a method of making a power
transmitting fluid having anti-shudder capabilities may comprise
adding to a major amount of a base oil a minor amount of an
additive composition having a non-dispersant viscosity index
improver.
[0015] In another embodiment, a method of making a lubricating
fluid having improved compatibility with an elasotmeric component
may comprise adding to a major amount of a base oil a minor amount
of an additive composition having a non-dispersant viscosity index
improver.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 illustrates torque performance of a fluid according
to an embodiment as measured using a ZF GK test rig.
[0017] FIG. 2 illustrates torque performance of a comparative fluid
measured using a ZF GK test rig.
DETAILED DESCRIPTION OF EMBODIMENTS
[0018] As power transmission fluids operate under increasingly
severe conditions, the oils used to lubricate those transmissions
should be formulated to endure higher temperatures and pressures.
To reduce equipment problems and increase the interval between
transmission oil changes, the oil should be formulated so that
important oil properties change as little as possible in the face
of these stresses. In particular, the shear stability properties of
the oil, which depend in great measure on the additive package,
should stay relatively constant over a wide range of temperatures
and operating speeds. This ensures smooth engagement of torque
converter and shifting clutches and minimized shudder, vibration
and noise, and improved fuel economy as constant viscosity allows
good hydraulic control.
[0019] The present disclosure describes compositions and methods
that provide and/or improve anti-shudder performance of power
transmission fluids, and also methods for providing and/or
improving the compatibility of lubricating fluids with elastomeric
components, for example, seals, gaskets, belts, and/or hoses.
Non-dispersant viscosity index improvers are known to improve
rheological properties, such as viscosity index, of power
transmission fluids and/or lubricating fluids. Thus, the
compositions of the present disclosure provide a single solution to
multiple problems, and thus an inherent cost benefit.
[0020] In an embodiment, a power transmission fluid may include a
base oil and an additive composition. The additive composition may
include a non-dispersant viscosity index improver. Non-dispersant
viscosity index improvers differ from dispersant viscosity index
improvers by the absence of dispersant functional groups. A
non-dispersant viscosity index improver suitable for use in at
least one of the present embodiments may comprise a
polymethacrylate, an olefin copolymer, a polystyrene, a metallocene
polymer, a polymer of a hydrogenated diene and/or a copolymer
thereof with a vinyl amine, a homopolymer of a hydrogenated
conjugated diene or a copolymer thereof with a vinyl aromatic
hydrocarbon, and the like. A wide range of molecular weight
polymers of the latter type can be utilized as the base polymer of
the non-dispersant viscosity index improver, and such polymers may
include linear, branched, or star-shaped configurations.
[0021] The presence of a non-dispersant viscosity index improver in
the compositions and methods of the present embodiments eliminate
and/or reduce the need for conventionally utilized
friction-modifying agents or other agents for providing
anti-shudder performance. Further, inclusion of a non-dispersant
viscosity index improver may improve the anti-shudder properties of
a fluid relative to a fluid including a dispersant viscosity index
improver. Embodiments may include an amount of a non-dispersant
viscosity index improver sufficient to provide and/or improve the
anti-shudder characteristics of a power transmission fluid. For
example, an additive composition may comprise from about 0.01 wt %
to about 50 wt % of non-dispersant viscosity index improver. As a
further example, an additive composition may comprise from about
1.0 wt % to about 25 wt % of non-dispersant viscosity index
improver. As an even further example, an additive composition may
comprise from about 3 wt % to about 15 wt % of non-dispersant
viscosity index improver.
[0022] In addition, some embodiments provide and/or improve
compatibility of elastomeric components found within an automotive
transmission, including an automatic and manual transmission, a
gear component, and/or an axle component. Such elastomeric
components may comprise seals, hoses, gaskets, belts, and the like.
Further, these components may be composed of elastomeric materials
such as nitrile rubber, polyacrylate, silicone, fluoroelastomers,
and/or chlorinated polyethylene. Elastomeric components may
deteriorate, shrink, or fail to swell properly because of contact
with certain chemicals contained in lubricating fluids. Further,
some chemicals, such as seal swell agents, may improve the
tolerance of seals and hoses to lubricating fluids. Embodiments
disclosed herein have been found to positively interact with seals
and hoses to improve tensile strength and/or elongation. Both of
these factors are indicative of proper seal swell and resistance or
tolerance to deterioration. Such embodiments include a lubricating
fluid comprising a non-dispersant viscosity index improver.
[0023] The presence of a non-dispersant viscosity index improver in
the compositions and methods of the present embodiments eliminate
and/or reduce the need for conventionally utilized seal swell
agents or other agents. For example, inclusion of a non-dispersant
viscosity index improver in a lubricating fluid may improve the
compatibility of the lubricating fluid with elastomeric components.
In particular, this improvement may be compared to fluids including
dispersant viscosity index improvers and/or fluids including a
conventional seal swell agent.
[0024] Embodiments may include a suitable amount of a
non-dispersant viscosity index improver sufficient to provide the
desired swelling and/or provide or improve the compatibility
between a lubricating fluid and elastomeric components. For
example, an additive composition may comprise from about 0.01 wt %
to about 50 wt % of non-dispersant viscosity index improver. As a
further example, an additive composition may comprise from about
1.0 wt % to about 25 wt % of non-dispersant viscosity index
improver. As an even further example, an additive composition may
comprise from about 3 wt % to about 15 wt % of non-dispersant
viscosity index improver.
[0025] Base Oil
[0026] Base oils suitable for use in formulating transmission fluid
compositions may be selected from any of the synthetic or natural
oils or mixtures thereof. Natural oils include animal oils and
vegetable oils (e.g., castor oil, lard oil) as well as mineral
lubricating oils such as liquid petroleum oils and solvent treated
or acid-treated mineral lubricating oils of the paraffinic,
naphthenic or mixed paraffinic-naphthenic types. Oils derived from
coal or shale are also suitable. The base oil typically has a
viscosity of about 2 to about 15 cSt or, as a further example,
about 2 to about 10 cSt at 100.degree. C. Further, gas-to-liquid
stocks are also suitable.
[0027] The synthetic base oils include alkyl esters of dicarboxylic
acids, polyglycols, and alcohols, poly-alpha-olefins, including
polybutenes, alkyl benzenes, organic esters of phosphoric acids,
and polysilicone oils. Synthetic oils include hydrocarbon oils such
as polymerized and interpolymerized olefins (e.g., polybutylenes,
polypropylenes, propylene isobutylene copolymers, etc.);
poly(1-hexenes), poly-(1-octenes), poly(1-decenes), etc. and
mixtures thereof; alkylbenzenes (e.g., dodecylbenzenes,
tetradecylbenzenes, di-nonylbenzenes, di-(2-ethylhexyl)benzenes,
etc.); polyphenyls (e.g., biphenyls, terphenyl, alkylated
polyphenyls, etc.); alkylated diphenyl ethers and alkylated
diphenyl sulfides and the derivatives, analogs and homologs thereof
and the like.
[0028] Alkylene oxide polymers and interpolymers and derivatives
thereof where the terminal hydroxyl groups have been modified by
esterification, etherification, etc., constitute another class of
known synthetic oils that may be used. Such oils are exemplified by
the oils prepared through polymerization of ethylene oxide or
propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene
polymers (e.g., methyl-polyisopropylene glycol ether having an
average molecular weight of about 1000, diphenyl ether of
polyethylene glycol having a molecular weight of about 500-1000,
diethyl ether of polypropylene glycol having a molecular weight of
about 1000-1500, etc.) or mono- and polycarboxylic esters thereof,
for example, the acetic acid esters, mixed C.sub.3-8 fatty acid
esters, or the C.sub.13 Oxo acid diester of tetraethylene
glycol.
[0029] Another class of synthetic oils that may be used includes
the esters of dicarboxylic acids (e.g., phthalic acid, succinic
acid, alkyl succinic acids, alkenyl succinic acids, maleic acid,
azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic
acid, linoleic acid dimer, malonic acid, alkyl malonic acids,
alkenyl malonic acids, etc.) with a variety of alcohols (e.g.,
butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl
alcohol, ethylene glycol, diethylene glycol monoether, propylene
glycol, etc.) Specific examples of these esters include dibutyl
adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctyl
sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl
phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl
diester of linoleic acid dimer, the complex ester formed by
reacting one mole of sebacic acid with two moles of tetraethylene
glycol and two moles of 2-ethylhexanoic acid and the like.
[0030] Esters useful as synthetic oils also include those made from
C.sub.5 to C.sub.12 monocarboxylic acids and polyols and polyol
ethers such as neopentyl glycol, trimethylol propane,
pentaerythritol, dipentaerythritol, tripentaerythritol, etc.
[0031] Hence, the base oil used which may be used to make the
transmission fluid compositions as described herein may be selected
from any of the base oils in Groups I-V as specified in the
American Petroleum Institute (API) Base Oil Interchangeability
Guidelines. Such base oil groups are as follows:
1 Sulfur Saturates Viscosity Base Oil Group.sup.1 (wt %) (wt %)
Index Group I >0.03 and/or <90 80 to 120 Group II
.ltoreq.0.03 And .gtoreq.90 80 to 120 Group III .ltoreq.0.03 And
.gtoreq.90 .gtoreq.120 Group IV all polyalphaolefins (PAOs) Group V
all others not included in Groups I-IV .sup.1Groups I-III are
mineral oil base stocks.
[0032] As set forth above, the base oil may be a poly-alpha-olefin
(PAO). Typically, the poly-alpha-olefins are derived from monomers
having from about 4 to about 30, or from about 4 to about 20, or
from about 6 to about 16 carbon atoms. Examples of useful PAOs
include those derived from octene, decene, mixtures thereof, and
the like. PAOs may have a viscosity of from about 2 to about 15, or
from about 3 to about 12, or from about 4 to about 8 cSt at
100.degree. C. Examples of PAOs include 4 cSt at 100.degree. C.
poly-alpha-olefins, 6 cSt at 100.degree. C. poly-alpha-olefins, and
mixtures thereof. Mixtures of mineral oil with the foregoing
poly-alpha-olefins may be used.
[0033] The base oil may be an oil derived from Fischer-Tropsch
synthesized hydrocarbons. Fischer-Tropsch synthesized hydrocarbons
are made from synthesis gas containing H.sub.2 and CO using a
Fischer-Tropsch catalyst. Such hydrocarbons typically require
further processing in order to be useful as the base oil. For
example, the hydrocarbons may be hydroisomerized using processes
disclosed in U.S. Pat. No. 6,103,099 or 6,180,575; hydrocracked and
hydroisomerized using processes disclosed in U.S. Pat. No.
4,943,672 or 6,096,940; dewaxed using processes disclosed in U.S.
Pat. No. 5,882,505; or hydroisomerized and dewaxed using processes
disclosed in U.S. Pat. No. 6,013,171; 6,080,301; or 6,165,949.
[0034] Unrefined, refined and rerefined oils, either natural or
synthetic (as well as mixtures of two or more of any of these) of
the type disclosed hereinabove can be used in the base oils.
Unrefined oils are those obtained directly from a natural or
synthetic source without further purification treatment. For
example, a shale oil obtained directly from retorting operations, a
petroleum oil obtained directly from primary distillation or ester
oil obtained directly from an esterification process and used
without further treatment would be an unrefined oil. Refined oils
are similar to the unrefined oils except they have been further
treated in one or more purification steps to improve one or more
properties. Many such purification techniques are known to those
skilled in the art such as solvent extraction, secondary
distillation, acid or base extraction, filtration, percolation,
etc. Rerefined oils are obtained by processes similar to those used
to obtain refined oils applied to refined oils which have been
already used in service. Such rerefined oils are also known as
reclaimed or reprocessed oils and often are additionally processed
by techniques directed to removal of spent additives, contaminants,
and oil breakdown products.
[0035] The base oil may be combined with an additive composition as
disclosed in embodiments herein to provide a power transmission
fluid. The base oil may be present in the power transmission fluid
in an amount from about 50 wt % to about 95 wt %.
[0036] Other Optional Components
[0037] The power transmission fluid may also include conventional
additives of the type used in automatic transmission fluid
formulations in addition to the components described above. Such
additives include, but are not limited to, ashless dispersants,
friction modifiers, antioxidants, extreme pressure additives,
corrosion inhibitors, antiwear additives, antirust additives, metal
deactivators, antifoamants, pour point depressants, air entrainment
additives, metallic detergents, and/or additional seal swell
agents.
[0038] Additives used in formulating the compositions described
herein can be blended into the base oil individually or in various
sub-combinations. However, it is suitable to blend all of the
components concurrently using an additive concentrate (i.e.,
additives plus a diluent, such as a hydrocarbon solvent). The use
of an additive concentrate takes advantage of the mutual
compatibility afforded by the combination of ingredients when in
the form of an additive concentrate simulates actual plant blending
conditions. Also, the use of a concentrate reduces blending time
and lessens the possibility of blending errors.
[0039] The power transmission fluids disclosed herein may include
fluids suitable for any power transmitting application, such as a
step automatic transmission, having from about 3 to about 7 speeds,
or a manual transmission. Further, the power transmission fluids of
the present disclosure are suitable for use in transmissions with a
slipping torque converter, a lock-up torque converter, a starting
clutch, and/or one or more shifting clutches. Such transmissions
include three-, four-, five-, six-, and seven-speed transmissions,
and continuously variable transmissions (chain, belt, or disk
type). They may also be used in manual transmissions, including
automated manual and dual-clutch transmissions.
EXAMPLES
[0040] Fluids tested in the following examples included the
following components prepared in the proportions disclosed below.
Components that were varied are discussed with respect to each
example below. Unless otherwise specified tested samples were
identical except for varied components.
2 Example 2 Example 2 Proportion in Proportion in Component type
Finished Fluid, wt % Finished Fluid, wt % Antioxidants 0.1-2.5
0.2-0.5 Rust Inhibitors 0-0.2 0-0.06 Thiadiazole 0-2.0 0.01-0.6
Antifoam agents 0-1.5 0.05-0.20 Friction Modifiers 0-5.0 0.005-0.25
Dispersant 0-10 1-5% .sup. Seal Swell Agents 0-20 0-10
Polymethacrylate 0.5-30 .sup. 3-25 viscosity index improver
Basestock 60-90 60-90 Diluent Oil 0-20 2-5
Example 1
[0041] Two transmission fluid formulations were tested and
evaluated for effectiveness in reducing shudder. Each fluid had
identical concentrations of supplemental additives and differed
only in the types of viscosity index improver.
[0042] A polymethacrylate non-dispersant viscosity index improver
was used in Formula A at a concentration of 5.13 wt %, and a
viscosity index improver with dispersant functionality was used in
Formula B at a concentration of 5.13 wt %.
[0043] As shown in FIGS. 1 and 2, the two automatic transmission
fluids were subjected to shudder testing by evaluating friction
characteristics using the ZF GK rig. This test was developed by ZF
to measure a slip-controlled clutch's opening and closing
performance. An interchangeable intermediate shaft allows the
measurement of frictional vibration that is the basis for
evaluation of "green" or initial shudder characteristics of the
test fluid. The Green Shudder portion of the "GVRK-Kurztest CFT23"
consists of a torque controlled continuous slip module, containing
three 20-minute sections. The entire sequence encompasses 60
minutes of test time. During each 20-minute section, force is
proportional to both slip speed and output torque. The result is a
0.345 m/s (50.0 rpm) constant clutch speed, with variable force to
control 100 Nm of output torque, which is also constant. Each
20-minute section is analyzed for torque variation. Due to the 1000
Hz speed data acquisition, shudder can be depicted. A 1-minute
stabilization period takes place between each continuous slip
section. Test fluid temperature is controlled at 120.degree. C.
[0044] Measurements in FIGS. 1 and 2 are displayed as torque over
the function of time. The variation in torque measurements is
indicative of shudder. Fluids without shudder will display constant
torque over time. Fluids with shudder will display varying torque
over time.
[0045] Shudder tests were run with a polymethacrylate
non-dispersant viscosity index improver fluid (Formula A) in FIG. 1
and a dispersant viscosity index improver (Formula B) in FIG. 2.
The green shudder characteristics of Formula A in FIG. 1 show a
reduction in green shudder associated with the incorporation of a
non-dispersant viscosity index improver. The results using Formula
A demonstrate no green shudder, as evidenced by constant torque
over time. The results using Formula B demonstrate varying torque
over time which is indicative of green shudder.
Example 2
[0046] The incorporation of a non-dispersant viscosity index
improver in a lubricating fluid was tested for compatibility by
representative elastomeric component. The component tested was a
hose composed of a chlorinated polyethylene. Table 1 demonstrates
the results obtained from the testing of several power transmission
fluid with the chlorinated polyethylene hose. The performance was
determined by the tensile strength and the elongation of the hose
at the end of the test, with a more positive number indicating
better performance. Sample 1 did not contain any of non-dispersant
viscosity index improver, dispersant viscosity index improver, or
seal swell agent. Sample 2 contained an equal amount of a
non-dispersant viscosity index improver and a dispersant viscosity
index improver. Sample 3 contained an equal amount of a
non-dispersant viscosity index improver and a dispersant viscosity
index improver and additionally a seal swell agent. Sample 4
contained a non-dispersant viscosity index improver and a seal
swell agent. All other components in the fluids tested were
identical.
3 TABLE 1 Sample 1 Sample 2 Sample 3 Sample 4 Non-dispersant 0.00
5.80 5.80 10.80 viscosity index improver, wt % Dispersant viscosity
0.00 5.80 5.80 0.00 index improver, wt % Seal Swell Agent, wt %
0.00 0.00 0.40 0.60 Tensile Strength, % -55.07 -52.22 -51.89 -41.89
Elongation, % -74 -77.74 -73.19 -68.48
[0047] The results shown in Table 1 show that Sample 4, which
contained non-dispersant viscosity index improver, demonstrated
superior tensile strength compared to samples having less or no
non-dispersant viscosity index improver. Furthermore, the
incorporation of a seal swell agent to Samples 3 and 4 did not
provide a significant benefit. Notably, the benefit achieved
through the use of solely the non-dispersant viscosity index
improver greatly exceeded that achieved by the mixed formulation
with or without the seal swell agent.
[0048] At numerous places throughout this specification, reference
has been made to a number of U.S. patents. All such cited documents
are expressly incorporated in full into this disclosure as if fully
set forth herein.
[0049] Other embodiments will be apparent to those skilled in the
art from consideration of the specification and practice of the
invention disclosed herein. As used throughout the specification
and claims, "a" and/or "an" may refer to one or more than one.
Unless otherwise indicated, all numbers expressing quantities of
ingredients, properties such as molecular weight, percent, ratio,
reaction conditions, and so forth used in the specification and
claims are to be understood as being modified in all instances by
the term "about." Accordingly, unless indicated to the contrary,
the numerical parameters set forth in the specification and claims
are approximations that may vary depending upon the desired
properties sought to be obtained by the present invention. At the
very least, and not as an attempt to limit the application of the
doctrine of equivalents to the scope of the claims, each numerical
parameter should at least be construed in light of the number of
reported significant digits and by applying ordinary rounding
techniques. Notwithstanding that the numerical ranges and
parameters setting forth the broad scope of the invention are
approximations, the numerical values set forth in the specific
examples are reported as precisely as possible. Any numerical
value, however, inherently contains certain errors necessarily
resulting from the standard deviation found in their respective
testing measurements. It is intended that the specification and
examples be considered as exemplary only, with a true scope and
spirit of the invention being indicated by the following
claims.
* * * * *