U.S. patent application number 16/993438 was filed with the patent office on 2021-02-18 for method for improving engine performance with renewable lubricant compositions.
The applicant listed for this patent is Chevron U.S.A. Inc.. Invention is credited to David S. LEE, Mihir K. PATEL, Willem VAN DAM.
Application Number | 20210047577 16/993438 |
Document ID | / |
Family ID | 1000005060737 |
Filed Date | 2021-02-18 |
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United States Patent
Application |
20210047577 |
Kind Code |
A1 |
VAN DAM; Willem ; et
al. |
February 18, 2021 |
METHOD FOR IMPROVING ENGINE PERFORMANCE WITH RENEWABLE LUBRICANT
COMPOSITIONS
Abstract
Provided herein are lubricant compositions comprising renewable
base oils as embodied by hydrocarbon mixtures with controlled
structure characteristics in combination with lubricant additives
that address performance requirements and stricter environmental
and fuel economy regulations. The lubricant composition provides
performance in the cold crank simulated viscosity (CCS) vs Noack
volatility relationship, which allows for the formulation of lower
viscosity engine oils with improved fuel economy, improved fuel
economy retention, and retained LSPI prevention additionally
conferring improved characteristics to other devices or apparatus
requiring lubrication.
Inventors: |
VAN DAM; Willem; (Novato,
CA) ; PATEL; Mihir K.; (San Ramon, CA) ; LEE;
David S.; (San Ramon, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chevron U.S.A. Inc. |
San Ramon |
CA |
US |
|
|
Family ID: |
1000005060737 |
Appl. No.: |
16/993438 |
Filed: |
August 14, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62886407 |
Aug 14, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 2203/022 20130101;
C10N 2030/02 20130101; C10N 2020/071 20200501; C10N 2040/25
20130101; C10N 2030/54 20200501; C10M 105/04 20130101 |
International
Class: |
C10M 105/04 20060101
C10M105/04 |
Claims
1. A method of improving fuel economy comprising lubricating an
internal combustion engine with a lubricant that comprises: a. (a)
a mixture of base oil having at least 25 wt. % renewable base oil
comprising a hydrocarbon mixture in which: i. the percentage of
molecules with even carbon number is .gtoreq.80% according to FIMS;
ii. the BP/BI.gtoreq.-0.6037 (Internal alkyl branching per
molecule)+2.0; iii. on average there are 0.3 to 1.5 5+ methyl per
molecule; b. at least one of the following additives i. dispersants
ii. detergents iii. Inhibitors iv. Friction Modifiers v. Pour Point
Depressants vi. Viscosity Modifiers
2. The method of claim 1, wherein the lubricating oil composition
comprises from about 5 wt. % to about 30 wt. % total additive
concentration and from about 70 to about 95 wt. % of the base oil
mixture.
3. The method of claim 1, wherein the composition has a lubricating
high temperature high shear viscosity less than 2.3 cP, based on
ASTM D5481.
4. The method of claim 1, wherein the composition has a lubricating
kinematic viscosity at 100.degree. C. less than or equal to 7.1
cSt, based on ASTM D445.
5. The method of claim 1, wherein the composition has a lubricating
low temperature cold cranking viscosity at -35.degree. C. less than
or equal to 6200 mPas, based on ASTM D5293.
6. The method of claim 1, wherein the lubricating composition has a
lubricating SAE viscosity grade less than or equal to 0W-12, based
on SAE J300.
7. The method of claim 1 wherein the fuel economy is improved by at
least 0.3% and preferably more than 0.5%.
8. A method of improving fuel economy retention comprising
lubricating an internal combustion engine with a lubricant that
comprises: a. a mixture of base oil having at least 25 wt. %
renewable base oil comprising a hydrocarbon mixture in which: i.
the percentage of molecules with even carbon number is .gtoreq.80%
according to FIMS; ii. the BP/BI.gtoreq.-0.6037 (Internal alkyl
branching per molecule)+2.0; iii. on average there are 0.3 to 1.5
5+ methyl per molecule; b. at least one of the following additives
i. dispersants ii. detergents iii. Inhibitors iv. Friction
Modifiers v. Pour Point Depressants vi. Viscosity Modifiers wherein
the lubricating oil composition comprises from about 5 wt. % to
about 30 wt. % total additive concentration and from about 70 to
about 95 wt. % of the base oil mixture.
9. The method of claim 7, wherein the composition has a lubricating
high temperature high shear viscosity less than 2.3 cP, based on
ASTM D5481.
10. The method of claim 7, wherein the composition has a
lubricating kinematic viscosity at 100.degree. C. less than or
equal to 7.1 cSt, based on ASTM D445.
11. The method of claim 7, wherein the composition has a
lubricating low temperature cold cranking viscosity at -35.degree.
C. less than or equal to 6200 mPas, based on ASTM D5293.
12. The method of claim 7, wherein the composition has a
lubricating oil SAE viscosity grade less than or equal to W-12,
based on SAE J300.
13. The method of claim 7, wherein typical drain interval fuel
economy loss is less than 0.5%, preferably less than 0%.
14. The method of claim 7, wherein extended drain interval fuel
economy loss is less than 0.4%, preferably less than 0%.
15. The method of claim 7, wherein the average fuel economy loss is
less than 0.5%, preferably less than 0% throughout the life of a
lubricant.
16. The method of claim 7, wherein there is an improvement in fuel
economy retention and a retention in low speed pre ignition
prevention in an internal combustion engine operated over an
extended period of exposure of the lubricant to elevated
temperature conditions.
Description
FIELD OF THE INVENTION
[0001] Methods for improving engine performance with lubricant
compositions containing a renewable base oil comprising hydrocarbon
mixtures and a lubricant additive have been developed which possess
unique compositional characteristics and which demonstrate superior
fuel economy improvement capability, fuel economy retention
properties over the life of the lubricant when used to lubricate
various types of internal combustion engines.
BACKGROUND OF THE INVENTION
[0002] Industry trends in engine oil formulation are moving to
lower viscosity regimes (0W-X) to enhance fuel economy benefits,
while also expecting to maintain current or better levels of
performance. However, as the industry moves to lower viscosity,
maintaining low oil consumption, and fuel economy durability
becomes challenging or even unattainable with available technology.
As the viscosity of the oil is reduced, the volatility increases,
leading to increased evaporation of the engine oil and increased
oil viscosity. Additionally, fuel economy can be enhanced by
lowering high temperature high shear (HTHS) viscosity of the oil.
HTHS is largely affected by viscosity modifiers which also regulate
cold and high temperature viscosity, thus a high viscosity index
(VI) oil is desirable. Some ultra low viscosity oils are on the
market, however they are unable to meet the most stringent
volatility requirements.
[0003] Base stocks are commonly used to produce various lubricants,
including lubricating oils for internal combustion engines,
turbines, compressors, hydraulic systems, etc. They are also used
as process oils, white oils, and heat transfer fluids. Finished
lubricants generally consist of two components, base oils and
additives. Base oil, which could be one or a mixture of base
stocks, is the major constituent in these finished lubricants and
contributes significantly to their performances, such as viscosity
and viscosity index, volatility, stability, and low temperature
performance. In general, a few base stocks are used to manufacture
a wide variety of finished lubricants by varying the mixtures of
individual base stocks and individual additives.
[0004] A method of improving engine fuel efficiency with a
lubricant composition containing fatty acid esters is set forth in
U.S. Pat. No. 9,885,004.
[0005] The American Petroleum Institute (API) categorizes base
stocks in five groups based on their saturated hydrocarbon content,
sulfur level, and viscosity index (Table 1 below). Group I, II, and
III base stocks are mostly derived from crude oil via extensive
processing, such as solvent refining for Group I, and
hydroprocessing for Group II and Group III. Certain Group III base
stocks can also be produced from synthetic hydrocarbon liquids via
a Gas-to-Liquids process (GTL), and are obtained from natural gas,
coal or other fossil resources. Group IV base stocks, the
polyalphaolefins (PAO), are produced by oligomerization of alpha
olefins, such as 1-decene. Group V base stocks include everything
that does not belong to Groups I-IV, such as naphthenic base
stocks, polyalkylene glycols (PAG), and esters. Most of the
feedstocks for large-scale base stock manufacturing are
non-renewable.
TABLE-US-00001 TABLE 1 API Base Oil Classification (API 1509
Appendix E) Viscosity Saturates Index by API (ASTM ASTM Sulphur,
Group D2270) D2007 % Description I 80-120 <90% >.03%
Conventional (solvent refining) II 80-120 .gtoreq.90% .ltoreq..03%
Hydroprocessing III .gtoreq.120 .gtoreq.90% .ltoreq..03% Severe
Hydroprocessing IV PolyAlphaOlefins (PAO) V All other base stocks
not included above e.g. esters
[0006] Automotive engine oils are by far the largest market for
base stocks. The automotive industry has been placing more
stringent performance specifications on engine oils due to
requirements for lower emissions, long drain intervals, and better
fuel economy. Specifically, automotive OEMs (original equipment
manufacturer) have been pushing for the adoption of lower viscosity
engine oils such as 0W-20 down to W-8 and even 0W-4, to lower
friction losses and achieve fuel economy improvement. Base Oils
with a lower Noack Volatility in an engine oil allows the
formulation to retain the designed viscosity for longer operation
time allowing for increased fuel economy retention and longer drain
intervals discussed in U.S. Pat. No. 6,300,291. Group I and Group
II's usage in engine oils with viscosity grade below 0W-20 engine
oils is highly limited because formulations blended with them
cannot meet the performance specifications for lower than 0W-20
engine oils, leading to increased demands for Group III and Group
IV base stocks.
[0007] Group III base stocks are mostly manufactured from vacuum
gas oils (VGOs) through hydrocracking and catalytic dewaxing (e.g.
hydroisomerization). Group III base stocks can also be manufactured
by catalytic dewaxing of slack waxes originating from solvent
refining, or by catalytic dewaxing of waxes originating from
Fischer-Tropsch synthesis from natural gas or coal based raw
materials also known as Gas to Liquids base oils (GTL).
[0008] Manufacturing processes of Group III base stocks from VGOs
is discussed in U.S. Pat. Nos. 5,993,644 and 6,974,535. Their
boiling point distributions are typically higher when compared to
PAOs of the same viscosity, causing them to have higher volatility
than PAOs. Additionally, Group III base stocks typically have
higher cold crank viscosity (i.e., dynamic viscosity according to
ASTM D5293, CCS) than Group IV base stocks at equivalent
viscosities.
[0009] GTL base stock processing is described in U.S. Pat. Nos.
6,420,618 and 7,282,134, as well as U.S. Patent Application
Publication 2008/0156697. For example, the latter publication
describes a process for preparing base stocks from a
Fischer-Tropsch synthesis product, the fractions of which with
proper boiling ranges are subjected to hydroisomerization to
produce GTL base stocks.
[0010] Such structures and properties of GTL base stocks are
described, for example, in U.S. Pat. Nos. 6,090,989 and 7,083,713,
as well as U.S. Patent Application Publication 2005/0077208. In
U.S. Patent Application Publication 2005/0077208, lubricant base
stocks with optimized branching are described, which have alkyl
branches concentrated toward the center of the molecules to improve
the base stocks' cold flow properties. Nevertheless, pour points
for GTL base stocks are typically worse than PAO or other synthetic
hydrocarbon base stocks.
[0011] A further concern with GTL base stocks is the severely
limited commercial supply, a result of the prohibitively large
capital requirements for a new GTL manufacturing facility. Access
to low cost natural gas is also required to profitably produce GTL
base stocks. Furthermore, as GTL base stocks are typically
distilled from an isomerized oil with a wide boiling point
distribution, the process results in a relatively low yield to the
base stock with a desired viscosity when compared to that of a
typical PAO process. Due to these monetary and yield constraints
there is currently only a single manufacturing plant of group
III+GTL base stocks, exposing formulations that use GTL to supply
chain and price fluctuation risks.
[0012] Polyalphaolefins (PAOs), or Group IV base oils, are produced
by the polymerization of alphaolefins in the presence of a Friedel
Crafts catalyst such as AlCl3, BF3, or BF3 complexes. For example,
1-octene, 1-decene, and 1-dodecene have been used to manufacture
PAOs that have a wide range of viscosities, varying from low
molecular weight and low viscosity of about 2 cSt at 100.degree.
C., to high molecular weight, viscous materials with viscosities
exceeding 100 cSt at 100.degree. C. The polymerization reaction is
typically conducted in the absence of hydrogen; the lubricant range
products are thereafter polished or hydrogenated to reduce the
residual unsaturation. Processes to produce PAO based lubricants
are disclosed, for example, in U.S. Pat. Nos. 3,382,291; 4,172,855;
3,742,082; 3,780,128; 3,149178; 4,956,122; 5,082,986; 7,456,329;
7,544,850; and U.S. Patent Application Publication 2014/0323665.
Prior efforts to prepare various PAOs that can meet the
increasingly stringent performance requirements of modern
lubricants and automotive engine oil particularly have favored low
viscosity polyalphaolefin base stocks derived from 1-decene, alone
or in some blend with other mineral oils. However, the
polyalphaolefins derived from 1-decene can be prohibitively
expensive due to its limited supply. Attempts to overcome the
availability constraint of 1-decene have led to the production of
PAOs from C8 through C12 mixed alpha-olefin feeds, lowering the
amount of 1-decene that is needed to impart the properties.
However, they still do not completely remove the requirement for
providing 1-decene as the predominate olefin feedstock due to
performance concerns.
[0013] Similarly, previous efforts to use linear alphaolefins in
the C14-C20 range made polyalphaolefins with unacceptably high pour
points, which are unsuitable for use in a variety of lubricants,
including 0W engine oils.
[0014] Therefore, there remains a need for a lubricant composition
having properties within commercially acceptable ranges, for
example, for use in automotive and other applications, with such
properties including one or more of viscosity, Noack volatility,
and low temperature cold-cranking viscosity. Furthermore, there
remains a need for lubricant compositions having improved
properties and methods of manufacture thereof, where the base stock
compositions have reduced amounts of 1-decene incorporated therein,
and may even preferably eliminate the use of 1-decene in the
manufacture thereof.
[0015] In addition to the technical demands for the automotive
industry, environmental awareness and regulations are driving
manufacturers to use renewable feedstocks and raw materials in the
production of base stocks and lubricants. It is known that esters
and some Group III hydrocarbon base stocks (U.S. Pat. No.
9,862,906B2) of renewable and biological origin have been used in
applications such as refrigeration compressor lubricants, hydraulic
oils and metal working fluids, and more recently in automotive and
industrial lubricants (US20170240832A1). Common biological sources
for hydrocarbons are natural oils, which can be derived from plant
sources such as canola oil, castor oil, sunflower seed oil,
rapeseed oil, peanut oil, soy bean oil, and tall oil, or palm oil.
Other commercial sources of hydrocarbons include engineered
microorganisms such as Algae or Yeast.
[0016] Due to increasing demand for high performing lubricant base
stocks there is a continuing need for improved hydrocarbon
mixtures. The industry requires these hydrocarbon mixtures to have
superior Noack Volatility, and low temperature viscometric
properties that can meet stricter engine oil requirements,
preferably from renewable sources.
[0017] The Automotive industry is trending towards downsizing
gasoline engines coupled with turbocharger and gasoline direct
injection to meet current and future CO2 regulations. To maximize
fuel economy, these engines are commonly calibrated to operate at
low speeds and high engine loads. Many of these downsized,
turbocharged engines have experienced uncontrolled combustion
events when engines operate under low speed-high load conditions,
commonly known as Low Speed Pre-ignition (LSPI). LSPI is random in
nature and gives a sudden rise in the pressure inside the cylinder
which can result in the catastrophic engine failure.
[0018] Many studies have evaluated the impact of the calcium treat
rate and concluded that increasing calcium content increases LSPI
occurrences. [12-14] Some researchers have proposed alternative
lubricant formulating strategies to reduce the occurrence of LSPI.
[12-14] In general, these lubricants were formulated by reducing
the amount of LSPI promoter (calcium containing detergent) and
increasing the amount of LSPI inhibitors (ZDDP, MoDTC, Mg
containing detergent etc.). However, reducing calcium content
beyond a certain limit can increase piston deposit, increase
varnish, increase acid concentration and reduction in the oil drain
interval. Hence, many studies have restricted the amount of calcium
containing detergent to 0.1 wt. %.
[0019] Therefore a lubricant composition which can improve fuel
economy retention while reducing LSPI is desired.
SUMMARY OF THE INVENTION
[0020] The present invention relates to a method of improving
engine performance by supplying an internal combustion engine with
a lubricant composition, containing a saturated hydrocarbon mixture
and lubricant additive with well-controlled structural
characteristics that address the performance requirements driven by
the stricter environmental and fuel economy regulations for
automotive engine oils. The branching characteristics of the
hydrocarbon molecules of the base oil portion are controlled to
consistently provide a composition that has a surprising CCS
viscosity at -35.degree. C. (ASTM D5329) and Noack volatility (ASTM
D5800) relationship.
[0021] An embodiment of the invention is a method where supplying
the lubricant composition to an internal combustion engine and
operation of the engine at elevated operating temperatures results
in a Fuel Economy Improvement (FEI) that is at least 0.3% better
than for a conventional lubricant of equal viscosity. In a
preferred embodiment the FEI is at least 0.5% better than for a
conventional lubricant of equal viscosity.
[0022] A further embodiment of the invention is a method where
supplying the lubricant composition to an internal combustion
engine and operation of the engine over an extended period of time
results in a Fuel Economy Retention (FER) benefit that is at least
0.5% better than for a conventional lubricant of equal viscosity.
In a preferred embodiment the FER is at least 1.0% better than for
a conventional lubricant of equal viscosity.
[0023] A further embodiment is a method where supplying the
lubricant composition to an internal combustion engine and
operation of the engine at elevated operating temperature over an
extended period of time results in an LSPI Prevention Retention
benefit by limiting the additive metal concentration increase. In a
preferred embodiment the Calcium concentration increase is limited
to no more than 15%.
[0024] An important aspect of the present invention relates to a
lubricant composition possessing a renewable base oil with a
saturated hydrocarbon mixture having greater than 80% of the
molecules with an even carbon number according to FIMS, with the
mixture exhibiting a branching characteristic of
BP/BI.gtoreq.-0.6037 (Internal alkyl branching per molecule)+2.0,
and when the hydrocarbon mixture is analyzed by carbon NMR as a
whole, has on average at least 0.3 to 1.5 5+ methyl branches per
molecule.
[0025] One way to synthesize the hydrocarbon mixture disclosed
herein is through oligomerization of C14-C20 alpha or
internal-olefins, followed by hydroisomerization of the oligomers.
Using C14-C20 olefins would ease the demand for high-price 1-decene
and other crude oil or synthetic gas based olefins as feedstocks,
and making available alternate sources of olefin feedstocks such as
those derived from C14-C20 alcohols. The hydrocarbon compositions
are derived from one or more olefin co-monomers, where said olefin
comonomers are oligomerized to dimers, trimers, and higher
oligomers. The oligomers are then subjected to hydroisomerization.
The resulting hydrocarbon mixtures have excellent pour point,
volatility and viscosity characteristics and additive solubility
properties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 illustrates the relationship between BP/BI and
Internal Alkyl Branches per Molecule for various hydrocarbons,
including low-viscosity PAO manufactured from 1-decene and
1-dodecene, GTL base oils, and hydroisomerized hexadecene
oligomers. The straight line in the plot depicts the equation of
BP/BI=-0.6037 (Internal alkyl branching per molecule)+2.0.
[0027] FIG. 2 illustrates the relationship between BP/BI and 5+
Methyl Branches per Molecule for various hydrocarbons, including
low-viscosity PAO manufactured from 1-decene and 1-dodecene, GTL
base oils, and hydroisomerized hexadecene oligomers. It
demonstrates that the 5+ Methyl Branches per Molecules for the
hydrocarbon mixtures disclosed in this patent fall in a unique
range of 0.3-1.5.
[0028] FIG. 3 illustrates the relationship between NOACK volatility
and CCS at -35.degree. C. for various hydrocarbons, including
low-viscosity PAO manufactured from 1-decene and 1-dodecene, GTL
base oils, Group III base oils, and hydroisomerized hexadecene
oligomers. The solid line and dotted line depicts the upper limit
and lower limit of the Noack vs. CCS at -35.degree. C. exhibited by
the present unique hydrocarbon mixture, which are NOACK=2,750 (CCS
at -35.degree. C.)(-0.8)+2 and NOACK=2,750 (CCS at -35.degree.
C.)(-0.8)-2, respectively.
[0029] FIG. 4 is an enlarged view of FIG. 3 in the range of
800-2,800 cP of CCS at -35.degree. C.
[0030] FIG. 5 is a graph of the fuel economy benefit as measured in
a modified sequence VIF test using three different lubricant
compositions.
[0031] FIG. 6 is a graph of the calcium content of three different
oils as measured in an extended duration test.
DETAILED DESCRIPTION OF THE INVENTION
[0032] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0033] Disclosed herein is a method for improving engine
performance; specifically supplying lubricant compositions
imparting improved fuel economy, improved fuel economy retention,
and improved LSPI Prevention Retention wherein the lubricant
compositions contain a renewable base oil stock containing a
saturated hydrocarbon mixture having a unique branching structure
as characterized by NMR that makes it suitable to be used as a
high-quality synthetic base stock and a lubricant additive. The
hydrocarbon mixture has outstanding properties including extremely
low volatility, good low-temperature properties, etc., which are
important performance attributes of high-quality base stocks. To be
specific, the mixture comprises greater than 80% of the molecules
with an even carbon number according to FIMS. The branching
characteristics of the hydrocarbon mixture by NMR comprises a BP/BI
in the range .gtoreq.-0.6037 (Internal alkyl branching per
molecule)+2.0. Moreover, on average, at least 0.3 to 1.5 of the
internal methyl branches are located more than four carbons away
from the end carbon. A saturated hydrocarbon with this unique
branching structure exhibits a surprising cold crank simulated
viscosity (CCS) vs. Noack volatility relationship that is
beneficial for blending low-viscosity automotive engine oils.
[0034] In one embodiment, the hydrocarbon mixtures described herein
are the product of oligomerization of olefins and a subsequent
hydroisomerization. C14 to C20 olefins are oligomerized to form an
oligomer distribution consisting of unreacted monomer, dimers
(C28-C40), and trimers and higher oligomers (.gtoreq.C42). The
unreacted monomers are distilled off for possible re-use in a
subsequent oligomerization. The remaining oligomers are then
hydroisomerized to achieve the final branching structures described
herein which consistently impart a surprising cold crank simulated
viscosity (CCS) vs. Noack volatility relationship.
Definitions
[0035] Renewable as used herein means any biologically derived
composition, including fatty alcohols, olefins, or oligomers. Such
compositions may be made, for nonlimiting example, from biological
organisms designed to manufacture specific oils, as discussed in WO
2012/141784, but do not include petroleum distilled or processed
oils such as, for nonlimiting example, mineral oils. A suitable
method to assess materials derived from renewable resources is
through "Standard Test Methods for Determining the Biobased Content
of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis"
(ASTM D6866-12 or ASTM D6866-11). Counts from 14C in a sample can
be compared directly or through secondary standards to SRM 4990C. A
measurement of 0% 14C relative to the appropriate standard
indicates carbon originating entirely from fossils (e.g., petroleum
based). A measurement of 100% 14C indicates carbon originating
entirely from modern sources (See, e.g., WO 2012/141784,
incorporated herein by reference).
[0036] Viscosity is the physical property that measures the
fluidity of the base stock. Viscosity is a strong function of
temperature. Two commonly used viscosity measurements are dynamic
viscosity and kinematic viscosity. Dynamic viscosity measures the
fluid's internal resistance to flow. Cold cranking simulator (CCS)
viscosity at -35.degree. C. for engine oil is an example of dynamic
viscosity measurements. The SI unit of dynamic viscosity is Pas.
The traditional unit used is centipoise (cP), which is equal to
0.001 Pas (or 1 m Pas). The industry is slowly moving to SI units.
Kinematic viscosity is the ratio of dynamic viscosity to density.
The SI unit of kinematic viscosity is mm2/s. The other commonly
used units in industry are centistokes (cSt) at 40.degree. C.
(KV40) and 100.degree. C. (KV100) and Saybolt Universal Second
(SUS) at 100.degree. F. and 210.degree. F. Conveniently, 1 mm2/s
equals 1 cSt. ASTM D5293 and D445 are the respective methods for
CCS and kinematic viscosity measurements. "Viscosity Grade" as used
herein refers to the lubricant composition containing a renewable
base oil formulated to meet the definition of an SAE XW-YY
lubricant (where X can be 0 or 5, and YY can be 4, 8, 12, 16, or
20). The properties for the various Viscosity Grades are further
defined in the SAE J300 Industry Standard
[0037] Viscosity Index (VI) is an empirical number used to measure
the change in the base stock's kinematic viscosity as a function of
temperature. The higher the VI, the less relative change is in
viscosity with temperature. High VI base stocks are desired for
most of the lubricant applications, especially in multigrade
automotive engine oils and other automotive lubricants subject to
large operating temperature variations. ASTM D2270 is a commonly
accepted method to determine VI.
[0038] Pour point is the lowest temperature at which movement of
the test specimen is observed. It is one of the most important
properties for base stocks as most lubricants are designed to
operate in the liquid phase. Low pour point is usually desirable,
especially in cold weather lubrication. ASTM D97 is the standard
manual method to measure pour point. It is being gradually replaced
by automatic methods, such as ASTM D5950 and ASTM D6749. ASTM D5950
with 1.degree. C. testing interval is used for pour point
measurement for the examples in this patent.
[0039] Volatility is a measurement of oil loss from evaporation at
an elevated temperature. It has become a very important
specification due to emission and operating life concerns,
especially for lighter grade base stocks. Volatility is dependent
on the oil's molecular composition, especially at the front end of
the boiling point curve. Noack (ASTM D5800) is a commonly accepted
method to measure volatility for automotive lubricants. The Noack
test method itself simulates evaporative loss in high temperature
service, such as an operating internal combustion engine.
[0040] Fuel Economy Improvement: the reduction in fuel consumption
for an engine running on the candidate oil relative to that
observed with the same engine running at the same test conditions
on a reference oil.
[0041] Fuel Economy Retention: the capability of a lubricant to
maintain its level of fuel consumption over a period of time where
that lubricant is exposed to aging conditions in an internal
combustion engine. Fuel Economy Retention can also be expressed as
the capability of a lubricant to retain its fuel economy
improvement over a period of time where the lubricant is exposed to
aging conditions in an internal combustion engine. Fuel Economy
Retention can also be expressed as a lack of fuel economy loss over
a period of time where the lubricant is exposed to aging conditions
in an internal combustion engine.
[0042] Boiling point distribution is the boiling point range that
is defined by the True Boiling Points (TBP) at which 5% and 95%
materials evaporates. It is measured by ASTM D2887 herein.
[0043] NMR Branching Analysis Branching parameters measured by NMR
spectroscopy for the hydrocarbon characterization include:
[0044] Branching Index (BI): the percentage of methyl hydrogens
appearing in the chemical shift range of 0.5 to 1.05 ppm among all
hydrogens appearing in the 1H NMR chemical range 0.5 to 2.1 ppm in
an isoparaffinic hydrocarbon.
[0045] Branching Proximity (BP): the percentage of recurring
methylene carbons which are four or more number of carbon atoms
removed from an end group or branch appearing at 13C NMR chemical
shift 29.8 ppm.
[0046] Internal Alkyl Carbons: is the number of methyl, ethyl, or
propyl carbons which are three or more carbons removed from end
methyl carbons, that includes 3-methyl, 4-methyl, 5+ methyl,
adjacent methyl, internal ethyl, n-propyl and unknown methyl
appearing between 13C NMR chemical shift 0.5 ppm and 22.0 ppm,
except end methyl carbons appearing at 13.8 ppm.
[0047] 5+ Methyl Carbons: is the number of methyl carbons attached
to a methine carbon which is more than four carbons away from an
end carbon appearing at 13C NMR chemical shift 19.6 ppm in an
average isoparaffinic molecule.
[0048] The NMR spectra were acquired using Bruker AVANCE 500
spectrometer using a 5 mm BBI probe. Each sample was mixed 1:1
(wt:wt) with CDCl3. The 1H NMR was recorded at 500.11 MHz and using
a 9.0 .mu.s (30.degree.) pulse applied at 4 s intervals with 64
scans co-added for each spectrum. The 13C NMR was recorded at
125.75 MHz using a 7.0 .mu.s pulse and with inverse gated
decoupling, applied at 6 sec intervals with 4096 scans co-added for
each spectrum. A small amount of 0.1 M Cr(acac)3 was added as a
relaxation agent and TMS was used as an internal standard.
[0049] The branching properties of the lubricant base stock samples
of the present invention are determined according to the following
six-step process. Procedure is provided in detail in US 20050077208
A1, which is incorporated herein in its entirety. The following
procedure is slightly modified to characterize the current set of
samples:
[0050] 1) Identify the CH branch centers and the CH3 branch
termination points using the DEPT Pulse sequence (Doddrell, D. T.;
D. T. Pegg; M. R. Bendall, Journal of Magnetic Resonance 1982, 48,
323ff.).
[0051] 2) Verify the absence of carbons initiating multiple
branches (quaternary carbons) using the APT pulse sequence (Patt,
S. L.; J. N. Shoolery, Journal of Magnetic Resonance 1982, 46,
535ff.).
[0052] 3) Assign the various branch carbon resonances to specific
branch positions and lengths using tabulated and calculated values
(Lindeman, L. P., Journal of Qualitative Analytical Chemistry 43,
1971 1245ff; Netzel, D. A., et. al., Fuel, 60, 1981, 307ff.).
Branch NMR Chemical Shift (ppm)
TABLE-US-00002 [0053] TABLE 2 Describes ppm shift of alkyl
branching by Carbon NMR Branch NMR Chemical Shift (ppm) 2-methyl
22.5 3-methyl 19.1 or 11.4 4-methyl 14.0 5+ methyl 19.6 Internal
ethyl 10.8 n-propyl 14.4 Adjacent methyl 16.7
[0054] 4) Quantify the relative frequency of branch occurrence at
different carbon positions by comparing the integrated intensity of
its terminal methyl carbon to the intensity of a single carbon
(total integral/number of carbons per molecule in the mixture). For
example, number of 5+ methyl branches per molecule is calculated
from the signal intensity at a chemical shift of 19.6 ppm relative
to intensity of a single carbon.
[0055] For the unique case of the 2-methyl branch, where both the
terminal and the branch methyl occur at the same resonance
position, the intensity was divided by two before doing the
frequency of branch occurrence calculation.
[0056] If the 4-methyl branch fraction is calculated and tabulated,
its contribution to the 5+ methyls must be subtracted to avoid
double counting.
[0057] Unknown methyl branches are calculated from contribution of
signals that appear between 5.0 ppm and 22.5 ppm, however not
including any branches reported in Table 2.
[0058] 5) Calculate the Branching Index (BI) and Branching
Proximity (BP) using the calculations described in U.S. Pat. No.
6,090,989, which is incorporated by reference herein in its
entirety.
[0059] 6) Calculate the total internal alkyl branches per molecule
by adding up the branches found in steps 3 and 4, except the
2-methyl branches. These branches would include 3-methyl, 4-methyl,
5+ methyl, internal ethyl, n-propyl, adjacent methyl and unknown
methyl.
[0060] FIMS Analysis: The hydrocarbon distribution of the current
invention is determined by FIMS (field ionization mass
spectroscopy). FIMS spectra were obtained on a Waters GCT-TOF mass
spectrometer. The samples were introduced via a solid probe, which
was heated from about 40.degree. C. to 500.degree. C. at a rate of
50.degree. C. per minute. The mass spectrometer was scanned from
m/z 40 to m/z 1000 at a rate of 5 seconds per decade. The acquired
mass spectra were summed to generate one averaged spectrum which
provides carbon number distribution of paraffins and cycloparaffins
containing up to six rings.
[0061] Hydrocarbon Structure and Properties The structure of the
hydrocarbon mixtures disclosed herein are characterized by FIMS and
NMR. FIMS analysis demonstrate that more than 80% of the molecules
in the hydrocarbon mixtures have an even carbon number.
[0062] The unique branching structure of the hydrocarbon mixtures
disclosed herein are characterized by NMR parameters, such as BP,
BI, internal alkyl branching, and 5+ methyls. BP/BI of the
hydrocarbon mixtures are in the range of .gtoreq.-0.6037 (Internal
alkyl branching per molecule)+2.0. The 5+ methyls of the
hydrocarbon mixtures average from 0.3 to 1.5 per molecule.
[0063] The hydrocarbon mixture can be classified into two carbon
ranges based on the carbon number distribution, C28 to C40 carbons,
and greater than or equal to C42. Generally, about or greater than
95% of the molecules present in each hydrocarbon mixture have
carbon numbers within the specified range. Representative molecular
structures for the C28 to C40 range can be proposed based on the
NMR and FIMS analysis. Without wishing to be bound to any one
particular theory, it is believed that the structures made by
oligomerization and hydroisomerization of olefins has methyl,
ethyl, butyl branches distributed throughout the structure and the
branch index and branch proximity contribute to the surprisingly
good low temperature properties of the product. Exemplary
structures in the present hydrocarbon mixture are as follows:
##STR00001##
[0064] The unique branching structure and narrow carbon
distribution of the hydrocarbon mixtures makes them suitable to be
used as high-quality synthetic base oils, especially for
low-viscosity engine oil applications. The hydrocarbon mixtures
exhibit: [0065] a KV100 in the range of 3.0-10.0 cSt; [0066] a pour
point in the range of -20 to -55.degree. C.; [0067] a Noack and CCS
at -35.degree. C. relationship such that Noack is between 2750 (CCS
at -35.degree. C.).sup.(-0.8).+-.2.
[0068] The Noack and CCS relationship for the hydrocarbon mixtures
are shown in FIGS. 3 and 4. In each figure, the top line represents
Noack=2750 (CCS at -35.degree. C.)(-0.8)+2 and the bottom graph
line represents Noack=2750 (CCS at -35.degree. C.)(-0.8)-2. More
preferably the hydrocarbon mixtures have a Noack and CCS at -35 C
relationship such that the Noack is between Noack=2750 (CCS at
-35.degree. C.)(-0.8)+0.5 and Noack=2750 (CCS at -35.degree.
C.)(-0.8)-2. Hydrocarbon mixtures that are closer to the origin in
FIGS. 3 and 4 have been found more advantageous for low viscosity
engine oils due to the low volatility and decreased viscosity at
-35.degree. C.
[0069] A hydrocarbon mixture in accordance with the present
invention with carbon numbers in the range of C28 to C40, and in
another embodiment carbon numbers in the range of from C28 to C36,
or in another embodiment molecules with a carbon number of C32,
will generally exhibit the following characteristics in addition to
the characteristics of BP/BI, Internal alkyl branches per molecule,
5+ methyl branches per molecule, and Noack/CCS relationship
described above: [0070] a KV100 in the range of 3.0-6.0 cSt; [0071]
a VI in the range of 11 ln(BP/BI)+135 to 11 ln(BP/BI)+145; and
[0072] a pour point in the range of 33 ln(BP/BI)-45 to 33
ln(BP/BI)-35.
[0073] In one embodiment, the KV100 for the C28-C40 hydrocarbon
mixture ranges from 3.2 to 5.5 cSt; in another embodiment the KV100
ranges from 4.0 to 5.2 cSt; and from 4.1 to 4.5 cSt in another
embodiment.
[0074] The VI for the C28-C40 hydrocarbon mixture ranges from 125
to 155 in one embodiment and from 135 to 145 in another
embodiment.
[0075] The Pour Point of the hydrocarbon mixture, in one embodiment
ranges from 25 to -55.degree. C. and from 35 to -45.degree. C. in
another embodiment.
[0076] The boiling point range of the C28-C40 hydrocarbon mixture
in one embodiment is no greater than 125.degree. C. (TBP at 95%-TBP
at 5%) as measured by ASTM D2887; no greater than 100.degree. C. in
another embodiment; no greater than 75.degree. C. in one
embodiment; no greater than 50.degree. C. in another embodiment;
and no greater than 30.degree. C. in one embodiment. In the
preferred embodiments, those with a boiling point range no greater
than 50.degree. C., and even more preferably no greater than
30.degree. C., give a surprisingly low Noack Volatility (ASTM
D5800) for a given KV100.
[0077] The C28-C40 hydrocarbon mixture in one embodiment has a
Branching Proximity (BP) in the range of 14-30 with a Branching
Index (BI) in the range of 15-25; and in another embodiment a BP in
the range of 15-28 and a BI in the range of 16-24.
[0078] The Noack volatility (ASTM D5800) of the C28-C40 hydrocarbon
mixture is less than 16 wt. % in one embodiment; less than 12 wt. %
in one embodiment; less than 10 wt. % in one embodiment; less than
8 wt. % in one embodiment and less than 7 wt. % in one embodiment.
The C28-C40 hydrocarbon mixture in one embodiment also has a CCS
viscosity at -35.degree. C. of less than 2700 cP; of less than 2000
cP in another embodiment; of less than 1700 cP in one embodiment;
and less than 1500 cP in one embodiment.
[0079] The hydrocarbon mixture with the carbon number range of C42
and greater will generally exhibit the following characteristics,
in addition to the characteristics of BP/BI, internal alkyl
branches per molecule, 5+ methyl branches per molecule, and Noack
and CCS at -35.degree. C. relationship described above: [0080] a
KV100 in the range of 6.0-10.0 cSt; [0081] a VI in the range of 11
ln(BP/BI)+145 to 11 ln(BP/BI)+160; and [0082] a Pour Point in the
range of 33 ln(BP/BI)-40 to 33 ln(BP/BI)-25.
[0083] The hydrocarbon mixture comprising C42 carbons or greater,
in one embodiment has a KV100 in the range of 8.0 to 10.0 cSt, and
in another embodiment from 8.5 to 9.5 cSt.
[0084] The VI of the hydrocarbon mixture having .gtoreq.42 carbons
is 140-170 in one embodiment; and, from 150-160 in another
embodiment.
[0085] The pour point in one embodiment ranges from -15 to
-50.degree. C.; and, from -20 to -40.degree. C. in another
embodiment.
[0086] In one embodiment, the hydrocarbon mixture comprising
.gtoreq.42 carbons has a BP in the range of 18-28 with a BI in the
range of 17-23. In another embodiment, the hydrocarbon mixture has
a BP in the range of 18-28 and a BI in the range of 17-23.
[0087] In general, both hydrocarbon mixtures disclosed above
exhibit the following characteristics: [0088] at least 80% of the
molecules have an even carbon number according to FIMS; [0089] a
KV100 in the range of 3.0-10.0 cSt; Sa pour point in the range of
-20 to -55.degree. C.; [0090] a Noack and CCS @ -35.degree. C.
relationship such that Noack is between 2750 (CCS @-35.degree.
C.).sup.(-0.8)-2; [0091] a BP/BI in the range of .gtoreq.-0.6037
(Internal alkyl branching)+2.0 per molecule; and, [0092] on average
from 0.3 to 1.5 5+ methyl branches per molecule.
Synthesis
[0093] Provided herein are possible processes or methods to make
the disclosed hydrocarbon mixtures. The novel hydrocarbon mixtures
disclosed herein can be synthesized via olefin oligomerization to
achieve the desired carbon chain length, followed by
hydroisomerization to improve their cold-flow properties, such as
pour point and CCS, etc. In one embodiment, olefins of C14 to C20
in length are oligomerized using an acid catalyst to form an
oligomer mixture. The olefins can be sourced from natural occurring
molecules, such as crude oil or gas based olefins, or from ethylene
polymerizations. In some variations, about 100% of the carbon atoms
in the olefin feedstocks described herein may originate from
renewable carbon sources. For example, an alpha-olefin co-monomer
may be produced by oligomerization of ethylene derived from
dehydration of ethanol produced from a renewable carbon source. In
some variations, an alpha-olefin co-monomer may be produced by
dehydration of a primary alcohol other than ethanol that is
produced from a renewable carbon source. Said renewable alcohols
can be dehydrated into olefins, using gamma alumina or sulfuric
acid. In some embodiments, modified or partially hydrogenated
terpene feedstocks derived from renewable resources are coupled
with one or more olefins that are derived from renewable
resources.
[0094] In one embodiment, an olefin monomer between C14 to C20 is
oligomerized in the presence of BF3 and/or BF3 promoted with a
mixture of an alcohol and/or an ester, such as a linear alcohol and
an alkyl acetate ester, using a continuously stirred tank reactor
(CSTR) with an average residence time of 60 to 400 minutes. In
another embodiment, the C14 to C20 olefin monomers are oligomerized
in the presence of BF3 and/or promoted BF3 using a continuously
stirred tank reactor with an average residence time of 90 to 300
minutes. In yet another embodiment, the C14 to C20 the olefin
monomers are oligomerized in the presence of BF3 and/or promoted
BF3 using a continuously stirred tank reactor with an average
residence time of 120 to 240 minutes. The temperature of the
oligomerization reaction may be in a range of from 10.degree. C. to
90.degree. C. However, in one preferred embodiment, the temperature
is maintained in the range of from 15 to 75.degree. C., and most
preferably 20.degree. C. to 40.degree. C., for the duration of the
reaction.
[0095] Suitable Lewis acids catalysts for the oligomerization
process include metalloid halides and metal halides typically used
as Friedel-Crafts catalysts, e.g., AlCl.sub.3, BF.sub.3, BF.sub.3
complexes, BCl.sub.3, AlBr.sub.3, TiCl.sub.3, TiCl.sub.4,
SnCl.sub.4, and SbCl.sub.5. Any of the metalloid halide or metal
halide catalysts can be used with or without a co-catalyst protic
promoter (e.g., water, alcohol, acid, or ester). In one embodiment,
the oligomerization catalyst is selected from the group consisting
of zeolites, Friedel-Crafts catalysts, Bronsted acids, Lewis acids,
acidic resins, acidic solid oxides, acidic silica
aluminophosphates, Group IVB metal oxides, Group VB metal oxides,
Group VIB metal oxides, hydroxide or free metal forms of Group VIII
metals, and any combination thereof.
[0096] Proper control of the oligomerization reaction temperature
and residence time within a CSTR is needed to ensure the dimer
portion (C28-C40) of the oligomerization product has branching
proximity (BP) between 25 to 35, preferably between 27-35, more
preferably between 27-33, and most preferably between 28-32, if the
dimer portion were to be saturated without isomerization to a Br
index of less than 100 mg Br.sub.2/100 g (ASTM D2710). A branching
proximity which is too low prior to hydroisomerization will lead to
isomerized hydrocarbon mixtures that fall under the solid line in
FIG. 1 and will result in a less desirable higher CCS viscosity at
-35.degree. C. value for a given Noack volatility to fit within the
range shown in FIGS. 3 and 4. Conversely, a branching proximity
which is too high will require greater isomerization to reach an
acceptable pour point, which will increase the Noack volatility and
the CCS at -35.degree. C. simultaneously. In one embodiment, the
unsaturated oligomer product is distilled to remove the unreacted
monomer. For example, the unreacted monomer may be separated from
the oligomer product, such as via distillation, and can be recycled
back into the mixture of the first and/or second feedstocks for
oligomerization thereof.
[0097] The oligomer product is then hydroisomerized to provide the
additional internal alkyl branches required to achieve the ideal
branching characteristics. In one embodiment, the whole oligomer
product, including both the dimers (C28-C40) and heavier oligomers
(.gtoreq.C42), are hydroisomerized prior to separation by
distillation. The hydroisomerized product is then separated into
the final hydrocarbon products by distillation. In another
embodiment, the dimers and heavier oligomers are fractionated and
hydroisomerized separately.
[0098] Hydroisomerization catalysts useful in the present invention
usually comprises a shape-selective molecular sieve, a metal or
metal mixture that is catalytically active for hydrogenation, and a
refractory oxide support. The presence of a hydrogenation component
leads to product improvement, especially VI and stability. Typical
catalytically active hydrogenation metals include chromium,
molybdenum, nickel, vanadium, cobalt, tungsten, zinc, platinum, and
palladium. Platinum and palladium are especially preferred, with
platinum mostly preferred. If platinum and/or palladium is used,
the metal content is typically in the range of 0.1 to 5 weight
percent of the total catalyst, usually from 0.1 to 2 weight
percent, and not to exceed 10 weight percent. Hydroisomerization
catalysts are discussed, for example, in U.S. Pat. Nos. 7,390,763
and 9,616,419, as well as U.S. Patent Application Publications
2011/0192766 and 2017/0183583.
[0099] The conditions for hydroisomerization are tailored to
achieve an isomerized hydrocarbon mixture with specific branching
properties, as described above, and thus will depend on the
characteristics of feed used. The reaction temperature is generally
between about 200.degree. C. and 400.degree. C., preferably between
260.degree. C. to 370.degree. C., most preferably between
288.degree. C. to 345.degree. C., at a liquid hourly space velocity
(LHSV) generally between about 0.5 hr.sup.-1 and about 20
hr.sup.-1. The pressure is typically from about 15 psig to about
2500 psig, preferably from about 50 psig to about 2000 psig, more
preferably from about 100 psig to about 1500 psig. Low pressure
provides enhanced isomerization selectivity, which results in more
isomerization and less cracking of the feed, thus leading to an
increased yield.
[0100] Hydrogen is present in the reaction zone during the
hydroisomerization process, typically in a hydrogen to feed ratio
from about 0.1 to 10 MSCF/bbl (thousand standard cubic feet per
barrel), preferably from about 0.3 to about 5 MSCF/bbl. Hydrogen
may be separated from the product and recycled to the reaction
zone.
[0101] In one embodiment, an additional step of hydrogenation is
added before the hydroisomerization to protect the downstream
hydroisomerization catalyst. In another embodiment, an additional
step of hydrogenation or hydrofinishing is added after the
hydroisomerization to further improve the saturation and stability
of the hydrocarbon mixture.
[0102] The hydroisomerized hydrocarbon mixtures are comprised of
dimers having carbon numbers in the range of C28-C40, and a mixture
of trimers+having carbon numbers of C42 and greater. Each of the
hydrocarbon mixtures will exhibit a BP/BI in the range of
.gtoreq.-0.6037 (internal alkyl branching) 2.0 per molecule, and,
on average, from 0.3 to 1.5 methyl branches on the fifth or greater
position per molecule. Importantly, at least 80% of the molecules
in each composition also have an even carbon number as determined
by FIMS. In another embodiment, each of the hydrocarbon
compositions will also exhibit a Noack and CCS at -35.degree. C.
relationship such that the Noack is between 2750 (CCS at
-35.degree. C.).sup.(-0.8)-2. These characteristics allow for the
formulation of low-viscosity engine oils as well as many other
high-performance lubricant products.
[0103] In one embodiment, C16 olefins are used as the feed for the
oligomerization reaction. When using C16 olefins as the feed, the
hydroisomerized dimer product generally exhibits a KV100 of 4.3 cSt
with <8% Noack loss and a CCS at -35.degree. C. of approximately
1,700 cP. The extremely low Noack volatility is due to the high
starting boiling point and narrow boiling point distribution when
compared other 3.9 to 4.4 cSt synthetic base stocks. This makes it
ideal for use in low viscosity engine oils with strict volatility
requirements. The excellent CCS and pour point characteristics are
due to the branching characteristics discussed above. In one
embodiment, the material has a pour point of .ltoreq.-40.degree. C.
This is required to pass critical engine oil formulation
requirements for 0W formulations, including Mini-Rotary Viscosity
(ASTM D4684) and Scanning Brookfield Viscosity (ASTM D2983)
specifications.
Finished Lubricant Formulations for Improving Engine
Performance
[0104] Herein is described the improvement of fuel economy, and the
retention of fuel economy and LSPI prevention of ultra-low
viscosity engine oils formulated using renewable base oils compared
to conventional base oils. Finished lubricant compositions
containing renewable base oils as herein described, not only
provide reduced friction and consequently improved fuel economy
when fresh, but also unexpectedly maintain reduced friction when
aged compared to conventional base oils formulations. These
benefits were leveraged into finished engine oil formulations to
demonstrate the fuel economy improvement and fuel economy retention
benefits using a modified Sequence VIF fuel economy engine test
stand. The test results indicate that the use of renewable base
oils in finished engine oil formulations provides an unexpected and
significant fresh oil fuel economy improvement which cannot be
explained from the viscometrics of the renewable-based lubricant.
In addition, the aged oil fuel economy is remarkably well retained
compared to conventional base oil engine oil formulations,
amounting to an unprecedented fuel economy improvement and
retention over the lifetime of the lubricant in the engine.
[0105] Also described herein is the reduced amount of Calcium
increase over the extended duration of exposure to elevated
operating temperature in the Sequence VIF engine, which will result
in an improved capability to retain the LSPI prevention
characteristics of the lubricant composition.
[0106] Lubricant compositions containing the renewable base oil
herein described can be employed in a variety of lubricant-related
end uses, such as a lubricant oil or grease for a device or
apparatus requiring lubrication of moving and/or interacting
mechanical parts, components, or surfaces. Useful apparatuses
include engines and machines. More specific equipment includes, but
is not limited to, gasoline fired engines, diesel fired engines,
natural gas fired engines, gear boxes, wind turbines and
circulating hydraulic pumps. Lubricant compositions containing the
base oil as herein described may be use in the formulation of
automotive crank case lubricants, automotive gear oils,
transmission oils, many industrial lubricants including circulation
lubricant, industrial gear lubricants, grease, compressor oil, pump
oils, refrigeration lubricants, hydraulic lubricants, metal working
fluids.
[0107] These benefits were observed in a Sequence VIF engine test
modified for extended time/duration and elevated temperature. A
Sequence VIF engine test as described in the ASTM D8226, as known
to one of skill in the art, comprises a comparative fuel economy
improvement (FEI) assessment of the fuel-saving capabilities of
automotive engine oils under repeatable laboratory conditions for
low-viscosity oils.
[0108] The test parameters are (1) The test duration is 196 hours,
(2) Fuel consumption is measured for six speed/load/temperature
test conditions for an SAE 20W-30 baseline (BL) lubricant to ensure
consistent engine response, (3) The candidate lubricant is
introduced and aged for 16 hours at aging conditions and then fuel
consumption is measured for six test conditions for FEI 1, (4) The
candidate lubricant is left in the engine and aged for 109 hours at
aging conditions for FEI 2, (5) Fuel consumption for each of the
six test conditions for BL is repeated at the end of the test to
further ensure consistent engine response over the duration of the
test. (5) FEI 1, FEI 2 and FEI Sum (FEI 1 plus FEI 2) are
calculated from the comparisons of the fuel economy measurements
for the candidate oil with the fuel economy measurements on the
baseline lubricant (BL).
[0109] Fuel consumption is measured for six speed/load/temperature
test conditions for an SAE 20W-30 baseline (BL) lubricant to ensure
consistent engine response. The candidate lubricant is introduced
and aged for 16 hours at aging conditions and then fuel consumption
is measured for six test conditions (Table 3). Fuel consumption for
each of the six test conditions for BL is repeated at the end of
the test to further ensure consistent engine response over the
duration of the test.
TABLE-US-00003 TABLE 3 Operating targets of a Sequence VIF engine
test are: Test Conditions Stage 1 Stage 2 Stage 3 Stage 4 Stage 5
Stage 6 Speed, rpm 2000 2000 1500 695 695 695 Torque, Nm 105 105
105 20 20 40 Lubricant 100 65 100 100 35 100 Temp, .degree. C.
Coolant-in 94 65 94 94 35 94 temp, .degree. C.
[0110] Modifications to this Sequence VIF engine test conditions
are presented.
TABLE-US-00004 TABLE 4 Modification of sequence VIF conditions
Stages Sequence VIF Mod. Sequence VIF 1 SOT BL FE 20W-30 20W-30 2
Flushing CO CO 3 Aging Phase 1 120.degree. C./16 h 120.degree.
C./16 h 4 CO FE (FEI1) Test conditions Test conditions (Table 3)
(Table 3)* 5 Aging Phase 2 120.degree. C./109 h 140.degree. C./144
h 6 CO FE (FEI2) Test conditions Test conditions (Table 3) (Table
3)* 7 Flushing 20W-30 -- 8 EOT BL FE 20W-30 -- 9 Aging Phase 3 --
140.degree. C./144 h 10 CO FE (FEI3) -- Test conditions (Table 3)*
11 Flushing -- 20W-30 12 EOT BL FE -- 20W-30 SOT--Start of Test:
BL--Baseline Oil; CO--Candidate Oil; FE--Fuel Economy Measurement;
EOT--End of the test; *FEI 1, 2, 3 based on unweighted fuel
consumption data
[0111] The lubricant of this invention comprises renewable base oil
used in the base oil mixture and further comprises one or more of
the following additives: dispersant, inhibitors, antioxidants,
detergents, friction modifiers, pour point depressants, viscosity
modifiers and the like.
[0112] In one embodiment the amount of renewable base oil in the
total amount of base oil is at least 20 wt. %. In another
embodiment, the amount of renewable base oil in the total amount of
base oil is from about 20 wt. % to about 100 wt. %. As is known in
the art, the fuel economy of an internal combustion engine is in
part determined by the viscosity and by the frictional
characteristics of the lubricant. The frictional characteristics of
a lubricant are determined by the additive chemistry in a sense
that the surface-active additives such as detergents anti-wear
additives and friction modifiers can form a solid,
friction-altering surface layer on the metal surfaces in the
lubricated contacts in the engine. Base oils are not expected, by
those skilled in the art, to play a role in altering the friction
in an engine as long as the viscosity of the lubricants is not
changed.
[0113] An embodiment of the invention describes a method to derive
a fuel economy improvement from a lubricant that comprises a
renewable base oil and has equal viscosity and the same additives
as a comparative lubricant that does not contain any of the
renewable base oil.
[0114] In one embodiment, the fuel economy improvement, when
employing a lubricating oil composition comprising 90 wt. % of the
renewable base oil and 10 wt. % of an additive combination that
includes dispersants, detergents, inhibitors, friction modifier,
and pour point depressant, is at least 0.3%, preferably 0.5% better
than for a conventional lubricant of equal viscosity that does not
comprise a renewable base oil.
[0115] As is known in the art, fuel economy improvement
measurements are performed on fresh lubricants or on lubricants
that have been exposed to a minor amount of aging at conditions
that represent moderately severe driving conditions. Also known is
that in many cases the driving conditions can be made more severe
by elevated ambient conditions, or by exposing the lubricant to
aging conditions for an extended duration, such as when oil change
intervals are extended. However, there are no standardized tools to
determine the fuel economy for a lubricant exposed to more severe
aging conditions, see Table 4, line 5 for severe aging conditions
as described herein.
[0116] This invention describes a method to derive a fuel economy
retention (FER) benefit from a lubricant that comprises a renewable
base oil and has equal viscosity and the same additives as a
comparative lubricant that does not contain any of the renewable
base oil. The fuel economy retention (FER) is evaluated after a
period of aging representative of a typical shorter oil change
interval. Separately, FER is evaluated after a period of aging
representative of an extended oil change interval.
[0117] In one embodiment, the fuel economy retention at conditions
representative of a shorter oil change interval, when employing a
lubricating oil composition comprising 90 wt. % of the renewable
base oil and 10 wt. % of an additive combination that includes
dispersants, detergents, inhibitors, friction modifier, and pour
point depressant, is at least 1.0% better, preferably 1.5% better
than for a conventional lubricant of equal viscosity that does not
comprise a renewable base oil.
[0118] In one embodiment, the fuel economy retention at conditions
representative of a shorter oil change interval, when employing a
lubricating oil composition comprising 45 wt. % of the renewable
base oil, 45% nonrenewable base oil and 10 wt. % of an additive
combination that includes dispersants, detergents, inhibitors,
friction modifier, and pour point depressant, is at least 0.5%
better, preferably 1.0% than a conventional lubricant of equal
viscosity that does not comprise a renewable base oil.
[0119] In one embodiment, the fuel economy retention (FER) at
conditions representative of an extended oil change interval, when
employing a lubricating oil composition comprising 90 wt. % of the
renewable base oil and 10 wt. % of an additive combination that
includes dispersants, detergents, inhibitors, friction modifier,
and pour point depressant, is at least 1.0% better, preferably 1.5%
better than for a conventional lubricant of equal viscosity that
does not comprise a renewable base oil.
[0120] In one embodiment, the fuel economy retention (FER) at
conditions representative of an extended oil change interval, when
employing a lubricating oil composition comprising 45 wt. % of the
renewable base oil, 45% non-renewable base oil and 10 wt. % of an
additive combination that includes dispersants, detergents,
inhibitors, friction modifier, and pour point depressant, is at
least 0.5% better, preferably 1.0% better than for a conventional
lubricant of equal viscosity that does not comprise a renewable
base oil.
[0121] In one embodiment, the fuel economy retention over a life of
a lubricant, when employing a lubricating oil composition
comprising 45 wt. % of the renewable base oil, 45% nonrenewable
base oil and 10 wt. % of an additive combination that includes
dispersants, detergents, inhibitors, friction modifier, and pour
point depressant, is at least 0.5% better, preferably 1.0% better
than a conventional lubricant of equal viscosity that does not
comprise a renewable base oil.
[0122] "Life of lubricant" as described herein comprises the period
from when the lubricant is put into the engine to the point where
the condition of the lubricant has degraded to a level where engine
damage may occur if the lubricant is not replenished.
[0123] In one embodiment, the fuel economy retention over a life of
a lubricant, when employing a lubricating oil composition
comprising 90 wt. % of the renewable base oil and 10 wt. % of an
additive combination that includes dispersants, detergents,
inhibitors, friction modifier, and pour point depressant, is at
least 1.0% better, preferably 1.5% better than a conventional
lubricant of equal viscosity that does not comprise a renewable
base oil.
[0124] A further embodiment of the invention is a method of
improving FER while retaining the low speed pre ignition (LSPI)
prevention capability in the operation of an internal combustion
engine over an extended period of time. Lubricant formulations were
aged by exposing them to the higher temperature in the GM High
Feature 3.6 L LY7 V6 engine attached to a dynamometer. Lubricant
formulations were aged in 2 steps. In the aging stage 1, the
lubricant formulation was subjected to 120.degree. C. for 16 hours.
In the subsequent aging stage, lubricant formulation was subjected
to 140.degree. C. for 288 hours. During the aging stages, the
lubricant was sampled at every 25 hours for used oil analysis and
chemical characterization to monitor changes in the lubricant
additives during the test.
[0125] As shown in the table 9 and FIG. 6, the Comparative Oils
(Examples 1, 2 and 3) all demonstrated a significant increase in
the calcium content as they aged in the engine. The calcium content
of Comparative Oils increased in the range of 20% to 76% at the end
of the test. Comparatively, the lubricant compositions of the
invention, as described herein maintained a calcium concentration
very close to the original value throughout the test duration.
[0126] Previous studies have concluded that higher viscosity base
stocks increase LSPI and volatility of the lubricants has
insignificant influence on LSPI occurrences. In the present work,
all the lubricants are formulated with base stocks with similar
kinematic viscosities. Based on the conclusions from previous
studies, one would predict that all four oils would show the same
behavior with respect to LSPI occurrences. However, previous
studies have concluded that increasing the concentration of calcium
leads to an increase in the LSPI rate. Comparative Oils 1, 2 and 3
have shown a significant increase in the calcium content as these
lubricants were exposed to higher temperature and extended duration
aging. Based on the conclusion of previous studies and results
shown in the table 9, we are predicting that all three Comparative
Oils will show increasing LSPI occurrences with the aging. In
contrast, the lubricant compositions as described herein will
retain its LSPI prevention performance throughout the test.
[0127] In certain variations, a base stock prepared according to
the methods described herein is blended with one or more additional
base stocks, e.g., one or more commercially available PAOs, a Gas
to Liquid (GTL) base stock, one or more mineral base stocks, a
vegetable oil base stock, an algae-derived base stock, a second
base stock as described herein, or any other type of renewable base
stock. Any effective amount of additional base stock may be added
to reach a blended base oil having desired properties. For example,
blended base oils can comprise a ratio of a first base stock as
described herein to a second base stock (e.g., a commercially
available base oil PAO, a GTL base stock, one or more mineral base
stocks, a vegetable oil base stock, an algae derived base stock, a
second base stock as described herein) that is about is from about
1-99%, from about 1-80%, from about 1-70%, from about 1-60%, from
about 1-50%, from about 1-40%, from about 1-30%, from about 1-20%,
or from about 1-10%, based on the total weight of the composition
may be made.
[0128] Also disclosed herein are lubricant compositions comprising
a hydrocarbon mixture described herein. In some variations, the
lubricant compositions comprise a base oil comprising at least a
portion of a hydrocarbon mixture produced by any of the methods
described herein, and one or more additives selected from the group
of antioxidants, viscosity modifiers, pour point depressants, foam
inhibitors, detergents, dispersants, dyes, markers, rust inhibitors
or other corrosion inhibitors, emulsifiers, de-emulsifiers,
antiwear agents, friction modifiers, thermal stability improvers,
multifunctional additives (e.g., an additive that functions as both
an antioxidant and a dispersant) or any combination thereof.
Lubricant compositions may comprise hydrocarbon mixtures described
herein and any lubricant additive, combination of lubricant
additives, or available additive package.
[0129] Any of the compositions described herein that are used as a
base stock may be present at greater than about 1% based on the
total weight of a finished lubricant composition. In certain
embodiments, the amount of the base stock in the formulation is
greater than about 2, 5, 15 or 20 wt. % based on the total weight
of the formulation. In some embodiments, the amount of the base oil
in the composition is from about 1-99%, from about 1-80%, from
about 1-70%, from about 1-60%, from about 1-50%, from about 1-40%,
from about 1-30%, from about 1-20%, or from about 1-10% based on
the total weight of the composition. In certain embodiments, the
amount of base stock in formulations provided herein is about 1%,
5%, 7%, 10%, 13%, 15%, 20%, 30%, 40%, 5 As is known in the art,
types and amounts of lubricant additives are selected in
combination with a base oil so that the finished lubricant
composition meets certain industry standards or specifications for
specific applications. In general, the concentration of each of the
additives in the composition, when used, may range from about 0.001
wt. % to about 20 wt. %, from about 0.01 wt. % to about 10 wt. %,
from about 0.1 wt. % to about 5 wt. % or from about 0.1 wt. % to
about 2.5 wt. %, based on the total weight of the composition.
Further, the total amount of the additives in the composition may
range from about 0.001 wt. % to about 50 wt. %, from about 0.01 wt.
% to about 40 wt. %, from about 0.01 wt. % to about 30 wt. %, from
about 0.01 wt. % to about 20 wt. %), from about 0.1 wt. % to about
10 wt. %, or from about 0.1 wt. % to about 5 wt. %, based on the
total weight of the composition. 0%, 60%, 70%, 80%, 90%, or 99%
based on total weight of the formulation.
[0130] In some variations, the base oils described herein are
formulated in lubricant compositions for use as two cycle engine
oils, as transmission oils, as hydraulic fluids, as compressor
oils, as turbine oils and greases, as automotive engine oils, as
gear oils, as marine lubricants, and as process oils. Process oils
applications include but are not limited to: rolling mill oils,
coning oils, plasticizers, spindle oils, polymeric processing,
release agents, coatings, adhesives, sealants, polish and wax
blends, drawing oils, and stamping oils, rubber compounding,
pharmaceutical process aids, personal care products, and inks.
[0131] In yet other variations, the base oils described herein are
formulated as industrial oil or grease formulations comprising at
least one additive selected from antioxidants, anti-wear agents,
extreme pressure agents, defoamants, detergent/dispersant, rust and
corrosion inhibitors, thickeners, tackifiers, and demulsifiers. It
is also contemplated that the base stocks of the invention may be
formulated as dielectric heat transfer fluids composed of
relatively pure blends of compounds selected from aromatic
hydrocarbons, polyalphaolefins, polyol esters, and natural
vegetable oils, along with additives to improve pour point,
increase stability and reduce oxidation rate.
[0132] The present invention will be further illustrated by the
following examples, which are not intended to be limiting.
EXAMPLES
Examples 1-6 (C28-C40 Hydrocarbon Mixtures)
Example 1
[0133] 1-Hexadecene with less than 8% branched and internal olefins
was oligomerized under BF3 with a co-catalyst composition of
Butanol and Butyl Acetate. The reaction was held at 20.degree. C.
during semi-continuous addition of olefins and co-catalyst. The
residence time was 90 minutes. The unreacted monomer was then
distilled off, leaving behind less than 0.1% monomer distillation
bottoms. A subsequent distillation was performed to separate the
dimer from the trimer+ with less than 5% trimer remained in the
dimer cut.
[0134] The dimers were then hydroisomerized with a noble-metal
impregnated aluminoslicate of MRE structure type catalyst bound
with alumina. The reaction was carried out in a fixed bed reactor
at 500 psig and 307.degree. C. Cracked molecules were separated
from the hydroisomerized C16 dimer using an online stripper.
Example 2
[0135] The oligomerization and subsequent distillation were
performed identically to Example 1. The dimers were then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MRE structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 313.degree. C.
Cracked molecules were separated from the hydroisomerized C16
dimers using an online stripper.
Example 3
[0136] The oligomerization and subsequent distillation were
performed identically to Example 1. The dimers were then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MRE structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 324.degree. C.
Cracked molecules were separated from the hydroisomerized C16
dimers using an online stripper.
Example 4
[0137] The oligomerization and subsequent distillation were
performed identically to Example 1. The dimers were then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MTT structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 316.degree. C.
Cracked molecules were separated from the hydroisomerized C16
dimers using an online stripper.
Example 5
[0138] The oligomerization and subsequent distillation were
performed identically to Example 1. The dimers were then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MTT structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 321.degree. C.
Cracked molecules were separated from the hydroisomerized C16
dimers using an online stripper.
Example 6
[0139] The oligomerization and subsequent distillation were
performed identically to Example 1. The dimers were then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MTT structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 332.degree. C.
Cracked molecules were separated from the hydroisomerized C16
dimers using an online stripper.
Examples 7-12 (C42 Hydrocarbon Mixtures)
Example 7
[0140] 1-Hexadecene with less than 8% branched and internal olefins
was oligomerized under BF3 with a co-catalyst composition of
Butanol and Butyl Acetate. The reaction was held at 20.degree. C.
during semi-continuous addition of olefins and co-catalyst. The
residence time was 90 minutes. The unreacted monomer was then
distilled off, leaving behind less than 0.1% monomer distillation
bottoms. A subsequent distillation was performed to separate the
dimer from the trimer and higher oligomers, the resulting dimer has
less than 5% trimer.
[0141] The trimer and higher oligomers (trimer+) cut was then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MRE structure type catalyst bound with alumina. The reaction was
carried out in a fixed bed reactor at 500 psig and 313.degree. C.
Cracked molecules were separated from the hydroisomerized C16
trimer+ using an online stripper.
Example 8
[0142] The oligomerization and subsequent distillations were
performed identically to Example 7. The trimer+ cut was then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MRE structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 318.degree. C.
Cracked molecules were separated from the hydroisomerized C16
trimer+ using an online stripper.
Example 9
[0143] The oligomerization and subsequent distillations were
performed identically to Example 7. The trimer+ cut was then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MRE structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 324.degree. C.
Cracked molecules were separated from the hydroisomerized C16
trimer+ using an online stripper.
Example 10
[0144] The oligomerization and subsequent distillations were
performed identically to Example 7. The trimer+ cut was then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MTT structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 321.degree. C.
Cracked molecules were separated from the hydroisomerized C16
trimer+ using an online stripper.
Example 11
[0145] The oligomerization and subsequent distillations were
performed identically to Example 7. The trimer+ cut was then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MTT structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 327.degree. C.
Cracked molecules were separated from the hydroisomerized C16
trimer+ using an online stripper.
Example 12
[0146] The oligomerization and subsequent distillations were
performed identically to Example 7. The trimer+ cut was then
hydroisomerized with a noble-metal impregnated aluminoslicate of
MTT structure type catalyst bound with alumina. The reaction was
carried out in a fix bed reactor at 500 psig and 332.degree. C.
Cracked molecules were separated from the hydroisomerized C16
trimer+ using an online stripper.
[0147] Inspection results for the hydrocarbon mixtures obtained in
examples 1-12 are summarized in Table 3 below.
TABLE-US-00005 TABLE 5 Pour CCS BP/ Internal 5+ KV40, KV100, Noack.
Point at -35.degree. Example BI Alkyl Methyl cSt cSt VI wt. %
(.degree. C.) C., cP No. 1 1.42 1.36 0.32 18.57 4.306 144 6.9 -30
1809 No. 2 1.19 1.67 0.50 18.67 4.297 142 NM* -36 1384 No. 3 0.80
2.24 0.95 19.01 4.290 136 7.9 -51 1581 No. 4 1.28 1.46 0.42 18.76
4.324 143 7.0 -32 1480 No. 5 1.06 2.20 0.60 18.85 4.313 141 NM* -38
1430 No. 6 0.75 2.21 0.88 18.99 4.303 138 8.0 -50 1558 No. 7 1.55
2.14 0.76 49.66 8.764 156 1.6 -19 26272 No. 8 1.30 2.57 1.17 49.99
8.744 154 1.6 -24 11278 No. 9 0.94 3.56 1.37 50.76 8.730 151 1.7
-34 10769 No. 10 1.41 2.75 1.14 48.93 8.642 156 1.9 -22 124967 No.
11 1.18 3.03 1.18 49.09 8.597 154 2.3 -28 18252 No. 12 0.95 2.94
1.29 49.44 8.533 150 2.2 -35 8589 *NM: not measure
[0148] Comparative GTL and PAO Base Stocks
[0149] Characterization results of comparable GTL and PAO samples
used in FIGS. 1-4 are summarized in Table 4. GTL comparative
examples shown in the following publications: GTL #1 WO2007068795,
GTL #2 WO2007068795, GTL #3 US2005007720. The PAO comparative
examples were measured using the techniques described above on
commercially available samples.
TABLE-US-00006 TABLE 6 Pour CCS BP/ Internal 5+ KV40, KV100, Noack,
Point at -35.degree. Samples BI Alkyl Methyl cSt cSt I wt. %
(.degree. C.) C., cP GTL #1 0.46 2 2 GTL #2 0.23 4 2 GTL #3 1.57
1.86 1.75 23.62 5.488 82 -9 C10 PAO #1 0.91 1.03 0.00 16.60 3.831
24 13.6 <-60 1435 C10 PAO #2 0.91 0.90 0.00 16.77 3.828 21 14.1
<-60 1117 C10 PAO #3 0.77 1.52 0.14 16.61 3.809 19 14.8 <-60
1192 C10 PAO #4 0.94 0.77 0.00 16.59 3.803 21 12.6 <-60 1324 C10
PAO #5 0.77 1.82 0.18 46.33 7.746 36 3.7 <-60 C10 PAO #6 0.93
0.99 0.05 46.50 7.795 36 3.4 <-60 C12 PAO #1 1.30 0.43 0.00
23.71 4.990 41 6.5 -47 2260 C12 PAO #2 1.40 0.55 0.00 39.05 7.139
47 3.2 -42
[0150] When the foregoing data is depicted graphically, the
important structural and property differences of the hydrocarbon
mixtures of the present invention, as compared to prior art
hydrocarbon mixtures, are clearly seen and support the surprisingly
improved properties of the present hydrocarbon mixtures. FIGS. 1-4
graphically depict several of the above characterizations.
[0151] FIG. 1 illustrates the relationship between BP/BI and
Internal Alkyl Branches per Molecule for the various hydrocarbon
mixtures. The straight line in the plot depicts the equation of
BP/BI -0.6037 (Internal alkyl branching per molecule)+2.0. All of
the hydrocarbon mixtures of the present invention are above the
line. While a few of the prior art hydrocarbon mixtures are also
above the line, they do not meet other important characteristics of
the present hydrocarbon mixtures, as shown in FIGS. 2-4.
[0152] FIG. 2 illustrates the relationship between BP/BI and 5+
Methyl Branches per Molecule for the various hydrocarbon mixtures.
It demonstrates that the 5+ Methyl Branches per Molecules for the
present hydrocarbon mixtures fall in a unique range of 0.3-1.5. All
of the prior art mixtures fall outside the range.
[0153] FIGS. 3 and 4 illustrate the relationship between NOACK
volatility and CCS at -35.degree. C. for the various hydrocarbon
mixtures. Some commercially available Group III base oils, which do
not meet the requirement of 80% even carbon number by FIMS, are
additionally included. The solid line and dotted line depicts the
upper limit and lower limit of the Noack vs. CCS at -35.degree. C.
exhibited by the present unique hydrocarbon mixture, which are
NOACK=2,750 (CCS at -35.degree. C.).sup.(-0.8)+2 and NOACK=2,750
(CCS at -35.degree. C.).sup.(-0.8)-2, respectively. It can be seen
that all of the present hydrocarbon mixtures fall within the range,
whereas essentially all of the prior art samples fall outside of
the range with the exception of a PAO of a higher viscosity that
does not have the desired branching as seen in FIGS. 1 and 2. FIG.
4 is an enlarged view of FIG. 3 in the range of 800-2,800 cP of CCS
at -35.degree. C. In general, for an engine oil formulation, a
preferable base stock will fall as close as possible to the origin
of FIGS. 3 and 4, as a lower Noack volatility for a given CCS
viscosity at -35.degree. C. is ideal for modern engine oil
formulations such as 0W-20 through 0W-8 formulations.
[0154] The foregoing data and figures demonstrate the unique
branching characteristics of the present hydrocarbon mixture, as
characterized by NMR, and the resulting unique properties. The
novel combination of structural characteristics has been found to
lead to outstanding properties, including extremely low volatility
and good low-temperature properties, which are important
performance attributes of high-quality base stocks.
Example 13
[0155] TABLE 7 shows a comparison of three lubricant compositions;
conventional capability, high volatility and lubricant compositions
of the invention as described herein when used in a modified
sequence VIF test for fuel economy improvement benefit. As shown in
Table 7, the lubricant of the invention which contained 90 wt. %
renewable base oil and 10 wt. % of an additive package containing
dispersants, detergents, inhibitors, friction modifier, and pour
point depressant, was blended to meet the viscosity grade
definition of an SAE 0W-8 lubricant. The kinematic viscosity of the
lubricant at 100.degree. C. was 5.47 cSt, the CCS Viscosity at
-35.degree. C. was 2400 cP, and the Noack volatility was 7%. A
comparative lubricant 1 was made with 90% of an API Group IV base
oil and 10 wt. % of the same additive package containing
dispersants, detergents, inhibitors, friction modifier, and pour
point depressant. This comparative lubricant was also blended to
meet the viscosity grade definition of an SAE 0W-8 lubricant. The
kinematic viscosity of the comparative lubricant at 100.degree. C.
was 4.82 cSt, the CCS Viscosity at -35.degree. C. was 2000 cP, and
the Noack volatility was 10.8%. A third oil used for comparative
purposes was purchased as it is a commercially available
lubricating oil. This lubricant also met the viscosity grade
definition of an SAE 0W-8 lubricant. The kinematic viscosity of the
third commercially available lubricant at 100.degree. C. was 5.31
cSt, the CCS Viscosity at -35.degree. C. was 1236 cP, and the Noack
volatility was 30.8%.
TABLE-US-00007 TABLE 7 Lubricating oil compositions and fuel
economy improvements Lubricant of Comparative Examples the
invention Example 1 Example 2 Group IV base oil -- 89.91 --
Renewable base oil 89.91 -- -- Additive Package 9.59 9.59 -- Pour
Pt. Dep. 0.5 0.5 -- Group IV base oil (Diluent oil) -- -- --
Commercial Oil -- -- 100 Total 100 100 100 Kinematic Viscosity @
100.degree. C. 5.5 4.8 5.3 CCS @ -35.degree. C. 2400 2000 1236 HTHS
@ 150.degree. C. 1.94 1.71 1.96 SAE Viscosity Grade 0W-8 0W-8 0W-8
NOACK @ 250.degree. C. 6.5 10.8 30.9 % FE Change relative to ref.
oil 3.7 2.52 2.84
[0156] A 5900 ml sample of the lubricant of the invention and the
two comparative lubricants were added to a GM 3.6 L V-6 engine
following a triple flushing procedure to eliminate all the remnants
of the reference lubricant that is evaluated before and after each
test on a candidate lubricant. Fuel Economy Improvements (FEI) are
expressed as a percentage increase or reduction in the amount of
fuel consumed relative to the fuel consumed on the reference
lubricant which is an SAE 20W-30 Viscosity Grade oil. Table 7
points out that comparative lubricants of an SAE 0W-8 Viscosity
Grade exhibit a fuel economy benefit based on their low viscosity,
in the range of 2.5 to 3.0% Fuel Economy Improvement (FEI). The
3.7% FEI that was found on the lubricant of the invention is a
highly surprising result as it improves the FE by 1.2% relative to
the Conventional Capability Comparative Example 1, which represents
a best-in-class result using high quality Group IV base oil. The
result is especially surprising considering that the viscosity of
these lubricants is nearly identical and the additive system, which
is responsible for the frictional characteristics, was completely
identical.
Example 14
TABLE-US-00008 [0157] TABLE 8 Lubricant of Comparative the
invention Exam- Exam- Exam- Exam- ple 1 ple 2 ple 1 ple 2
Commercial Oil 100 -- -- -- Non-renewable -- 89.91 44.26 --
synthetic base oil Renewable base oil -- -- 46.65 89.91 Additive
Package -- 9.59 9.59 9.59 Pour Pt. Dep. -- 0.5 0.5 0.5 Total 100
100 100 100 KV @ 100.degree. C. 5.3 4.8 4.4 5.5 CCS @ -35.degree.
C. 1236 2000 1394 2400 HTHS @ 150.degree. C. 1.96 1.71 1.65 1.94
SAE Viscosity Grade 0W-8 0W-8 0W-8 0W-8 NOACK @ 250.degree. C. 30.9
10.8 14.2 6.5 % FE change relative to 1.17 1.88 3.07 3.92 ref. oil
after typical drain interval (172 h) % FE change relative to -0.28
2.04 3.37 4 ref. oil after extended drain interval (328 h) Average
% FE change 0.445 1.96 3.219 3.958 over life of a lubricant
[0158] TABLE 8 shows a comparison of four lubricant compositions,
two showing conventional capability and two lubricant compositions
of the invention as described herein when used in a modified
Sequence VIF test for fuel economy retention benefit. As shown in
the Table 8 lubricating oil composition of the invention 1 which
contained 45 wt. % renewable base oil, 45% non-renewable base oil
and 10 wt. % of an additive package containing dispersants,
detergents, inhibitors, friction modifier, and pour point
depressant, was blended to meet the viscosity grade definition of
an SAE 0W-8 lubricant. The kinematic viscosity of the lubricant at
100.degree. C. was 4.4 cSt, the CCS Viscosity at -35.degree. C. was
1394 cP, and the Noack volatility was 14%. A lubricating oil
composition of the invention 2 which contained 90 wt. % renewable
base oil and 10 wt. % of an additive package containing
dispersants, detergents, inhibitors, friction modifier, and pour
point depressant, was blended to meet the viscosity grade
definition of an SAE 0W-8 lubricant. The kinematic viscosity of the
lubricant at 100.degree. C. was 5.5 cSt, the CCS Viscosity at
-35.degree. C. was 2400 cP, and the Noack volatility was 7%. A
comparative oil 1 used for comparative purposes was purchased as it
is a commercially available lubricating oil. This lubricant also
met the viscosity grade definition of an SAE 0W-8 lubricant. The
kinematic viscosity of the third commercially available lubricant
at 100.degree. C. was 5.31 cSt, the CCS Viscosity at -35.degree. C.
was 1236 cP, and the Noack volatility was 30.8%. A comparative
lubricant 2 was made with 90% of an API Group IV base oil and 10
wt. % of the same additive package containing dispersants,
detergents, inhibitors, friction modifier, and pour point
depressant. This comparative lubricant was also blended to meet the
viscosity grade definition of an SAE 0W-8 lubricant. The kinematic
viscosity of the comparative lubricant at 100.degree. C. was 4.82
cSt, the CCS Viscosity at -35.degree. C. was 2000 cP, and the Noack
volatility was 10.8%.
[0159] 5900 ml samples of the lubricants of the invention and the
two comparative lubricants were added to a GM 3.6 L V-6 engine
following a triple flushing procedure to eliminate all the remnants
of the reference lubricant that is evaluated before and after each
test on a candidate lubricant. Fuel Economy Improvements (FEI) are
expressed as a percentage increase or reduction in the amount of
fuel consumed relative to the fuel consumed on the reference
lubricant which is an SAE 20W-30 Viscosity Grade oil.
[0160] The GM 3.6 L engine was operated at conditions that are
defined in more detail in the ASTM Sequence VIF engine test, with
the exception of the lubricant temperature which was increased from
120.degree. C. to 140.degree. C. during the extended aging period.
Detailed description of modified test conditions is summarized in
table 4. Each candidate test was started with a fuel economy
measurement on the lubricant in its fresh state, followed by
additional fuel economy measurements after 172 h of lubricant aging
and again after 328 h of lubricant aging. After 172 hours of aging,
the lubricant would experience degradation similar to typical drain
interval conditions. Hence fuel economy measurement conducted after
172 hours test duration represents degradation in the fuel economy
at typical drain interval conditions. After 328 hours of aging, the
lubricant would experience degradation similar to extended drain
interval conditions. Hence fuel economy measurement conducted after
328 hours test duration represents degradation in the fuel economy
at extended drain interval conditions. The aging conditions are
defined in more detail in the ASTM Sequence VIF engine test. The
fuel economy evaluations were based on the total fuel consumption
measurements of the 6 stages that are defined in more detail in the
table 3.
[0161] Table 8 also summarizes fuel economy change (%) relative to
the reference oil after lubricants were aged similar to typical and
extended drain interval conditions. Furthermore, table 8 summarizes
average change in the fuel economy (%) over the life of a
lubricants. Average change in the fuel economy values were
calculated by averaging the values of fuel economy change (%) at
typical and extended drain intervals.
[0162] As shown in the table 8, comparative lubricants after aging
in the engine at elevated temperature, show a quickly increasing
disadvantage relative to the lubricant of the invention, which does
not suffer at all from a loss of fuel economy benefit, in other
words, it has superior fuel economy retention over the life of the
lubricant. For example, when comparative example 1 and 2 were aged
similar to typical drain interval conditions, they exhibit fuel
economy improvement in the range of 1% to 2%. While lubricants of
the invention retain fuel economy improvement benefits in the range
of 3% to 4%.
[0163] Furthermore, when comparative examples 1 was aged similar to
extended drain interval conditions, it lost all its fuel economy
improvement benefits and showed higher fuel consumption than the
reference oil. Comparative example 2 maintained its fuel economy
benefits around 2% when it was aged similar to extended drain
interval conditions. While lubricants of the invention retained
fuel economy improvement benefits in the range of 3% to 4% when
they were aged in the extended drain interval conditions.
[0164] In typical and extended drain interval conditions,
lubricants of the invention 1 and 2 shows fuel economy retention
benefits by about 1% to 2% better than comparative examples, which
represents best-in-class results using high quality group IV base
oil. These results are highly surprising. The improvement in the
fuel economy retention benefits cannot be explained by differences
in the NOACK volatility. For example, in the extended drain
interval conditions, high volatility comparative examples 1 and
best-in-class comparative 2 shows 20% NOACK volatility difference
and about 2% fuel economy benefits. Based on this, one skilled in
the art would expect the lubricant of the invention 2 would bring
0.4% fuel economy benefits based on 4% NOACK volatility difference
between comparative example 2 and lubricant of the invention 2. The
result however points out that there is >2% fuel economy
benefits between comparative example 2 and lubricant of the
invention 2. Furthermore, the lubricant of the invention 1
exhibited a 1.3% fuel economy improvement relative to best in class
comparative example 2 even though its NOACK volatility is about 4%
higher.
TABLE-US-00009 TABLE 9 Lubricant Lubricant Exam- Exam- of the of
the ple 1 ple 2 invention 1 invention 2 Commercial Oil 100 -- -- --
Non-renewable -- 89.91 44.26 -- synthetic base oil Renewable base
oil -- -- 46.65 89.91 Additive Package -- 9.59 9.59 9.59 Pour Pt.
Dep. -- 0.5 0.5 0.5 Total 100 100 100 100 KV @ 100.degree. C. 5.3
4.8 4.4 5.5 CCS @ -35.degree. C. 1236 2000 1394 2400 HTHS @
150.degree. C. 1.96 1.71 1.65 1.94 SAE Viscosity Grade 0W-8 0W-8
0W-8 0W-8 NOACK @ 250.degree. C. 30.9 10.8 14.2 6.5 Ca at start of
the test 2006 1585 1597 1573 Ca at end of the test 3534 1902 2024
1595 (340 hr) % increase in Ca 76.17 20% 26.73 1.3%
[0165] TABLE 9 shows a comparison of four lubricant compositions,
two showing conventional capability and two lubricant compositions
of the invention as described herein when used in a modified
Sequence VIF test, showing the reduced level of Calcium
concentration increase after exposure to elevated temperature in
the engine over the duration of an extended drain interval.
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