CN116761872A

CN116761872A - Lubricating oil composition with renewable base oil having low sulfur and sulfated ash content and containing molybdenum and boron compounds

Info

Publication number: CN116761872A
Application number: CN202180077308.4A
Authority: CN
Inventors: W·万达姆; M·K·帕特尔
Original assignee: Chevron USA Inc
Current assignee: Chevron USA Inc
Priority date: 2020-10-28
Filing date: 2021-10-27
Publication date: 2023-09-15
Also published as: WO2022090946A1; KR20230095094A; CA3200102A1; US20220127545A1; JP2023547487A; EP4237520A1

Abstract

A lubricant composition and method for improving engine performance are described that employ a renewable base oil composition comprising a hydrocarbon mixture and a lubricant additive having a sulfur content of at most about 0.4 wt% and a sulfated ash content of at most about 0.5 wt%.

Description

Lubricating oil composition with renewable base oil having low sulfur and sulfated ash content and containing molybdenum and boron compounds

Technical Field

A lubricating oil composition containing a renewable base oil comprising a hydrocarbon mixture and a lubricant additive having a sulfur content of up to about 0.4 wt.% and a sulfated ash content of up to about 0.5 wt.%. A method of improving engine performance utilizing a lubricating oil composition having been developed which contains a renewable base oil comprising a hydrocarbon mixture and a lubricant additive having a sulfur content of up to about 0.4 wt.% and a sulfated ash content of up to about 0.5 wt.%, which has unique composition characteristics and exhibits improvements in fuel economy maintenance, turbocharger efficiency maintenance, peak torque maintenance, peak power maintenance, exhaust manifold temperature reduction, and reduced oil usage over the life of the lubricant when used in lubricating various types of internal combustion engines.

Background

To mitigate global warming, emissions regulations in the automotive industry are stringent year by year. Due to these regulations, the automotive industry is seeking options to improve Fuel Economy (FE).

Because of its lower cost than redesigned hardware due to the fuel economy derived from advanced lubricants, it is increasingly seen as an attractive approach to improving efficiency. OEMs are seeking higher vehicle efficiency and have also begun to seek ways to maintain vehicle efficiency. Therefore, maintaining fuel economy over the life of the lubricant is becoming an important criterion. During operation of an automotive engine, the lubricant is degraded by its oxidation and thermal degradation. Oxidation and thermal degradation can degrade lubrication characteristics such as viscosity, oxidation resistance, wear resistance, and the like. Such degradation may lead to premature failure of critical engine components and loss of fuel economy.

Base stocks are commonly used to produce a variety of lubricants, including lubricating oils for internal combustion engines, turbines, compressors, hydraulic systems, and the like. They can also be used as process oils, white oils and heat transfer fluids. Finished lubricants are typically composed of two components, a base oil and an additive.

Base oils (which may be a base oil or a mixture of base oils) are the major components of these finished lubricants and are highly beneficial for their properties such as viscosity and viscosity index, volatility, stability and low temperature properties. Generally, some base stocks are used to make a variety of finished lubricants by varying the mixture of the individual base stocks and the individual additives.

U.S.9,885,004 outlines a method of improving engine fuel efficiency using a lubricant composition containing fatty acid esters.

The American Petroleum Institute (API) classifies base stocks into five categories based on their saturated hydrocarbon content, sulfur content and viscosity index (table 1 below). Group I, group II and group III base stocks are produced from crude oil primarily by rough processing, such as solvent refining for group I, and hydrotreating for group II and group III. Certain group III base stocks may also be produced from synthetic hydrogen liquids by Gas To Liquids (GTL) processes and obtained from natural gas, coal, or other fossil resources. Group IV base stocks, i.e., poly-alpha-olefins (PAOs), are produced by the oligomerization of alpha-olefins such as 1-decene. Group V base stocks include all materials that do not fall within groups I through IV, such as naphthenic base stocks, polyalkylene glycols (PAGs), and esters. Most feedstocks for large scale base stock manufacture are not renewable.

TABLE 1 API base oil Classification (API 1509 appendix E)

To date, automotive engine oils are the largest base stock market. The automotive industry has been subject to stricter performance specifications for engine oils due to lower emissions, longer oil change cycles, and better fuel economy requirements. In particular, automotive OEMs (original equipment manufacturers) have been pushing to employ lower viscosity engine oils, such as 0W-20 to 0W-8, to reduce friction losses and achieve fuel economy improvements. US6300291 discusses that base oils with lower Noack volatility in engine oils allow the formulation to maintain a design viscosity for longer operating times, allowing for increased fuel economy maintenance and longer oil change cycles. Because the formulations blended with group I and group II fail to meet the performance specifications of 0W-xx engine oils, their use in 0W-xx engine oils is very limited, resulting in increased demand for group III and group IV base stocks.

Group III base stocks are manufactured from Vacuum Gas Oil (VGO) primarily by hydrocracking and catalytic dewaxing (e.g., hydroisomerization). Group III base stocks may also be made by catalytic dewaxing loose waxes derived from solvent refining or by catalytic dewaxing fischer-tropsch waxes derived from natural gas or coal-based feedstocks, also known as gas to liquids base oils (GTL).

The manufacturing process for making group III base stocks from VGO is discussed in U.S. patent nos. 5,993,644 and 6,974,535. Their boiling point profile is generally broader than that of PAOs of the same viscosity, resulting in their higher volatility than PAOs. Additionally, at equivalent temperatures and viscosities, group III basestocks typically have a higher cold start viscosity (i.e., dynamic viscosity according to ASTM D5293, CCS) than group IV basestocks.

GTL base stock processing is described in U.S. patent nos. 6,420,618 and 7,282,134 and U.S. patent application publication 2008/0156697. For example, the latter publication describes a process for producing a base stock from a Fischer-Tropsch product, a fraction of the Fischer-Tropsch product having a suitable boiling range being subjected to hydroisomerization to produce a GTL base stock.

Such structures and characteristics of GTL base stocks are described, for example, in U.S. patent nos. 6,090,989 and 7,083,713 and U.S. patent application publication 2005/0077508. In U.S. patent application publication 2005/0077508, lubricant base stocks with optimized branching are described that have alkyl branches concentrated toward the center of the molecule to improve the cold flow properties of the base stock. However, the pour point of GTL base stocks is typically higher than that of PAOs or other synthetic hydrocarbon base stocks.

Another concern with GTL base stocks is that the commercial supply is very limited, which is a result of the excessive capital requirements of new GTL manufacturing facilities. There is also a need to obtain low cost natural gas to advantageously produce GTL base stocks. In addition, because GTL base stocks are typically distilled from oil isomerates having a broad boiling point profile, the process yields a base stock yield having the desired viscosity that is relatively low compared to the base stock yield of a typical PAO process. Because of these economic and yield limitations, there is currently only one group iii+gtl base stock manufacturer that exposes the formulation of GTLs to supply chain and price volatility risks.

Poly-alpha-olefins (PAO) or group IV base oils are produced by polymerization of alpha-olefins in the presence of Friedel Crafts catalysts such as AlCl3, BF3 or BF3 complexes. For example, 1-octene, 1-decene, and 1-dodecene have been used to make PAOs having a wide range of viscosities, ranging from low molecular weight and low viscosity materials of about 2cSt at 100deg.C to viscous materials having high molecular weights in excess of 100cSt at 100deg.C. The polymerization is generally carried out in the absence of hydrogen; the lubricant series product is then polished or hydrogenated to reduce residual unsaturation. Processes for producing PAO-based lubricants are described, 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; disclosed in U.S. patent application publication 2014/032365.

Previous efforts to make various PAOs that can meet the increasingly stringent performance requirements of modern lubricants and automotive engine oils have been particularly favored for low viscosity poly-alpha-olefin base stocks derived from 1-decene (either alone or in some blend with other mineral oils). However, poly-alpha-olefins derived from 1-decene may be too expensive due to limited supply. Attempts to overcome the usability limitations of 1-decene have led to the production of PAOs from C8 to C12 mixed alpha olefin feeds, thereby reducing the amount of 1-decene required to impart these characteristics. However, they have not completely eliminated the need to provide 1-decene as the primary olefin feedstock for performance considerations.

Similarly, previous efforts to use linear alpha-olefins in the C14-C20 range have resulted in poly-alpha-olefins with unacceptably high pour points that are unsuitable for use in a variety of lubricants, including 0W engine oils.

Thus, there remains a need for lubricant compositions having properties within a commercially acceptable range, for example, for automotive and other applications, wherein such properties include one or more of viscosity, noack volatility, and low temperature cold start viscosity. Furthermore, there remains a need for lubricant compositions having improved properties and methods of making the same, wherein the base stock composition has a reduced amount of 1-decene incorporated therein, and even preferably eliminates the use of 1-decene in its manufacture.

In addition to the technical requirements of the automotive industry, environmental awareness and regulations have prompted manufacturers to use renewable feedstocks and raw materials in the production of base stocks and lubricants. It is well known that renewable and bio-derived esters and some group III hydrocarbon basestocks (US 9862906B 2) have been used in applications such as refrigeration compressor lubricants, hydraulic oils and metalworking fluids, and more recently also in automotive and industrial lubricants (US 20170240832 A1). Common biological sources of hydrogen are natural oils, which may be derived from plant sources such as rapeseed oil, castor oil, sunflower oil, rapeseed oil, peanut oil, soybean oil, and tall or palm oil. Other commercial sources of hydrogen include engineered microorganisms such as algae or yeast.

As the demand for high performance lubricant base stocks continues to increase, there is a continuing need for improved hydrocarbon mixtures. Industry requires that these hydrogen mixtures have excellent Noack volatility and low temperature viscosity characteristics that can meet the more stringent engine oil requirements, preferably from renewable sources.

The exhaust aftertreatment device is mounted on the internal combustion engine so that it can comply with emission regulations. Combustion byproducts of fuel and lubricant can shorten the service life of the exhaust aftertreatment device. In particular, sulfur from fuels and lubricants, phosphorus from lubricants, and sulfated ash from lubricants are known to reduce the durability of exhaust gas aftertreatment devices. Accordingly, to extend the life of exhaust aftertreatment devices, certain types of lubricants, commonly referred to as low SAPS formulations, are being developed with reduced amounts of sulfated ash, phosphorus, and sulfur.

U.S. patent No. 9,523,061B2 discloses a lubricating oil composition having a sulfur content of up to about 0.4 wt.% and sulfated ash of up to about 0.5 wt.%.

Disclosure of Invention

One embodiment of the present invention is a lubricating oil composition containing a renewable base oil comprising a hydrocarbon mixture and a lubricant additive package having a sulfur content of up to about 0.4 wt.% and a sulfated ash content of up to about 0.5 wt.%.

Another embodiment is a method of improving engine performance utilizing a lubricating oil composition that has been developed that contains a renewable base oil that contains a hydrocarbon mixture and a lubricant additive package that has a sulfur content of up to about 0.4 wt.% and a sulfated ash content of up to about 0.5 wt.%, the lubricating oil composition having improved characteristics that exhibit fuel economy retention, turbocharger efficiency retention, peak torque retention, peak power retention, exhaust manifold temperature reduction, and reduced oil usage over the life of the lubricant when used to lubricate various types of internal combustion engines.

Detailed Description

According to one embodiment of the invention, a lubricant composition has a "renewable base oil", which is defined herein as a base oil having a saturated hydrocarbon mixture with more than 80% of molecules having an even number of carbons according to FIMS, wherein the mixture exhibits BP/BI ∈0.6037 (internal alkyl branches/molecule) +2.0 branching characteristics, and the hydrocarbon mixture has an average of at least 0.3 to 1.5 5 +methyl branches/molecule when the hydrocarbon mixture is analyzed in its entirety by carbon NMR. One method of synthesizing the hydrocarbon mixtures disclosed herein is by oligomerization of C14-C20 alpha or internal olefins followed by hydroisomerization of the oligomers.

The use of C14-C20 olefins will alleviate the need for higher 1-decene and other crude oil or syngas based olefins as feedstock and make available alternative sources of olefin feedstock such as those derived from C14-C20 alcohols. The hydrocarbon composition is derived from one or more olefin comonomers, wherein the olefin comonomer oligomerizes into dimers, trimers, and higher oligomers. The oligomers are then hydroisomerized. The resulting hydrocarbon mixtures have excellent pour point, volatility and viscosity properties and additive dissolution properties.

One embodiment of the present invention is a lubricating oil composition having the above-described renewable base oil blended with an additive package providing a sulfur content of up to about 0.4 wt.% and a sulfated ash content of up to about 0.5 wt.% as determined by ASTM D874, the additive package comprising (1) an oil-soluble boron-containing compound that contributes about 400ppm and no more than 2000ppm boron, based on the total mass of the composition, and preferably about 600ppm and no more than 1000ppm boron, based on the total mass of the composition; (2) An oil-soluble molybdenum-containing compound that contributes about 700ppm molybdenum and no more than 1500ppm molybdenum, based on the total mass of the composition, wherein the lubricating oil composition has a sulfur to molybdenum ratio of from about 0.5:1 to less than and equal to 4:1; further wherein the lubricating oil composition is substantially free of zinc dialkyldithiophosphate (zinc dialkyl dihiophosphate) compounds. Representative additive packages are described in U.S.9,523,061b2, incorporated herein by reference.

In accordance with another embodiment of the present invention, a lubricating oil composition having a renewable base oil and a low sulfated ash additive package, wherein the kinematic viscosity at 100 ℃ is less than or equal to 12.5cSt based on ASTM D445; the high temperature, high shear viscosity is less than or equal to 3.2cP based on ASTM D5481; a low temperature cold start viscosity of less than or equal to 6600mpa.s at-30 ℃ based on ASTM D5293; based on SAE J300, the SAE viscosity grade is less than or equal to 5W-30, such as 5W-20, 0W-30, 0W-20, 0W-16, 0W-12, and 0W-8.

"conventional lubricants" are defined herein as lubricant compositions that do not employ the "renewable base oils" described herein.

An "internal combustion engine" as defined herein includes diesel engines, including heavy duty and medium duty diesel engines.

Another embodiment of the invention is a method wherein supplying the lubricant composition to a heavy duty diesel engine results in an improvement in fuel efficiency maintenance, wherein the internal combustion engine comprises a diesel engine. Specifically, this results in an improvement in fuel economy retention of at least 0.2% as compared to a conventional lubricant of the same viscosity, and a method for improving fuel efficiency retention in an internal combustion engine preferably by more than 0.4%.

A further embodiment is a method of reducing oil usage by supplying a lubricant composition to a heavy duty diesel engine. The total oil usage describes the lubricant consumed during engine operation and the lubricant lost due to the loss of effectiveness of the lubricant in lubricating the internal combustion engine. The reduction in oil usage is at least 30%, and preferably more than 50%, as measured against a conventional lubricant of the same viscosity.

The method of supplying the lubricating composition described herein to a heavy duty diesel engine results in an extended oil change period of at least 50%, preferably more than 60%, compared to a conventional lubricant of the same viscosity.

The method of supplying a lubricant composition to a medium diesel engine as described herein provides additional improvements comprising:

(a) The fuel economy loss relative to the start of the test is less than 5%, and preferably no more than 3%, compared to a conventional lubricant of the same viscosity;

(b) The total oil consumption is lower than 7500 grams, preferably lower than 6500 grams, compared to a conventional lubricant of equivalent viscosity;

(c) Peak torque loss relative to the start of the test does not exceed 50Nm, and preferably does not exceed 30Nm, compared to a conventional lubricant of the same viscosity;

(d) Peak power loss relative to the start of the test is no more than 20KW, and preferably no more than 10KW, compared to a conventional lubricant of the same viscosity;

(e) Turbocharger efficiency losses are less than 10%, and preferably no more than 5%.

(f) The exhaust manifold temperature increase relative to the start of the test is less than 50 ℃ and preferably no more than 20 ℃ compared to a conventional lubricant of the same viscosity.

Examples

Comparative lubricating oil composition 1 was prepared by blending a group II mineral base oil with an additive package having conventional sulfated ash levels. Comparative lubricating oil composition 2 was prepared by blending a group II mineral base oil with an additive package having a low sulfated ash level. Comparative lubricating oil composition 3 was prepared by blending a renewable base oil with an additive package having conventional sulfated ash levels. The lubricant of the present invention is prepared by blending a renewable base oil with an additive package having a low sulfated ash level. The viscosity modifier and the conditioning fluid are added to obtain a kinematic viscosity at 100 ℃ between 7.25cSt and 8.25cSt and a high shear viscosity at 150 ℃ between 2.5cP and 2.6 cP. Table 1 shows the detailed composition of the lubricating oil and the corresponding additive concentrations.

TABLE 1 lubricating oil compositions

Test in heavy duty diesel engine:

it is well known that during operation of an automotive engine, lubricants degrade due to their oxidation and thermal degradation. Oxidation and thermal degradation can degrade lubrication characteristics such as viscosity, oxidation resistance, wear resistance, and the like. This can lead to premature failure of critical engine components and increased fuel consumption or loss of fuel economy. To measure fuel economy loss and oil usage, a Volvo D-13/MP8 13L in-line six-cylinder four-cycle diesel engine operating on ultra-low sulfur diesel equipped with a turbocharger and exhaust gas recirculation was used.

Measurement of Fuel economy maintenance (%)

To measure the fuel economy retention due to deterioration of lubrication characteristics during engine operation, a test was devised that sequentially measures fuel efficiency-oil deterioration (aging) -fuel efficiency. This cycle is repeated until engine operation exhibits significant fuel economy losses.

The fuel efficiency cycle is run as a discrete mode cycle using the EPA Supplemental Emission Test (SET) program. The SET cycle includes 13 mode steady state engine dynamometer testing. In each mode, the engine is run at a particular speed and load combination for a prescribed time and then moved to the next mode. The 13-mode cycle was repeated seven times and the average fuel consumption in grams per minute was measured for the seven cycles. An oil degradation (aging) cycle was performed at an engine speed of 1500rpm, a fuel flow rate of 68kg/h, and an oil passage temperature of 130 ℃. A detailed description of degradation (aging) test conditions is described in ASTM D8048.

The fuel economy retention test begins by measuring the fuel consumption of an engine oil filled with undegraded lubricant using the 13-mode SET cycle as described above. Thereafter an oil degradation (aging) cycle is performed according to the engine test conditions described above. The oil degradation cycle was performed for 90 hours. Thereafter, a fuel efficiency cycle was performed to measure a change in fuel consumption due to oil degradation for 90 hours. The fuel efficiency-oil degradation-fuel efficiency cycle was repeated for 360 hours, each segment being equal for 90 hours.

Further, the fuel consumption values (at each 90-hour segment) of the undegraded lubricant and the aged lubricant were used to calculate the fuel economy change (%). Further, by averaging the average of the fuel economy change calculated at 90, 180, 270 and 360 hours, the average fuel economy change after 360 hours of engine operation is calculated. A summary of the average fuel economy change for the comparative examples and the lubricants of the present invention is provided in table 2.

Determination of oil change cycle Capacity

Lubricating oils operating for 360 hours under the test conditions described in ASTM D8048 may deteriorate their lubricating properties and may no longer be useful for normal engine operation. Once the oil has degraded to this point, it should be drained from the engine and replaced with fresh oil. The limits of rejection of lubricants depend on the application and the severity of the application. Those skilled in the art know that it is difficult to determine a uniform discard point or discard limit for all lubricating oils. Thus, for a given experiment, a fuel efficiency loss of 0.5% was used as the lube oil change point. Thus, an oil change period (ODI) is defined as the period of engine operation in hours from the start of the test to the replacement of new lubricating oil. If any lubricating oil does not exhibit a 0.5% fuel economy loss at 360 hours of engine operation, the test cycle is extended until it exhibits a 0.5% fuel economy degradation. A summary of the oil change cycles after a 0.5% fuel economy loss for the comparative examples and the lubricants of the present invention is provided in table 2.

Determination of oil usage

The total lubricant used during engine operation is calculated by summing the initial charge of fresh lubricant and the lubricant consumed during engine operation. The initial charge of lubricant was 21.5kg. The lubricant consumed during engine operation is calculated by monitoring the lubricant level in the engine for a test duration, periodically checking the oil level indicator, and converting the observed lubricant level into the amount of oil present in the engine. This amount was then corrected for the lubricant sample taken from the engine and with the amount of fresh lubricant added every 30 hours to maintain the lubricant level. The total lubricant consumed after 360 hours was calculated by adding the oil consumed in grams per 30 hour interval. A summary of the total oil consumed by the comparative examples and the lubricants of the present invention after 360 hours of engine operation is provided in table 2.

Table 2 lubricant compositions and corresponding fuel economy change (%) and oil change cycles

Table 2 summarizes the average fuel economy change (%) after 360 hours of lubricant aging, the oil change period at 0.5% fuel economy of the engine lost, and the total oil consumed after 360 hours. As shown in table 2, the lubricant of the present invention exhibited the lowest change in fuel economy loss after 360 hours of its deterioration, compared to the comparative example. In addition, the lubricant of the present invention exhibited the longest oil change period as compared to the comparative example. Further, the lubricant of the present invention exhibited the lowest amount of oil consumed after 360 hours of engine operation, as compared to the comparative example.

Comparative example 1 was formulated with a conventional base oil and a conventional lubricant additive package. Comparative example 2 was formulated by replacing the conventional lubricant additive package with a low sulfated ash additive package and leaving the conventional base oil unchanged. Comparative example 3 was formulated by replacing the conventional base oil with a renewable base oil and leaving the conventional lubricant additive package unchanged. The lubricants of the present invention are formulated with a low sulfated ash additive package and a renewable base oil. To determine their relative properties, comparative examples 2, 3 and the lubricants of the present invention were compared with example 1. For example, examples 2 and 3 exhibited fuel economy maintenance improvements of 0.104% and-0.098% relative to example 1. Whereas the lubricant of the present invention exhibited 0.481% fuel economy retention improvement over example 1. These results demonstrate that combining the renewable base oil and the low sulfated ash additive package will improve fuel economy retention beyond the sum of the contributions of the low sulfated ash additive package (example 2) and the renewable base oil (example 3), respectively. This indicates a synergistic effect between renewable base oils and low sulfated ash additive technology. Similarly, an improvement in ODI after an engine loss of 0.5% fuel economy is also indicative of synergy between renewable base oils and low sulfated ash additive technologies.

Testing of a medium diesel engine:

the crankcase of an internal combustion engine accumulates gas and oil mist, which is called blow-by gas. Crankcase blow-by gases may be a source of particulate emissions and also result in increased oil consumption, accumulation of deposits on pistons and liners, and reduced engine cleanliness. Some IC engines use a Closed Crankcase Ventilation (CCV) system to mitigate the detrimental effects of blow-by gases on the environment. The united states EPA has classified CCV as a retrofit system that reduces PM by about 10%. In CCV systems, blow-by gas is recirculated through an Oil Mist Separator (OMS) to the engine intake system for return to the combustion process. OMS operate according to the coalescence principle to separate oil from gas. As the blow-by gas passes through the medium (filter or baffle), droplets of oil collect on the surface of the medium. These droplets coalesce and accumulate at the bottom of the OMS and return to the sump. The clean blow-by gas is mixed with the engine intake and passed through the turbocharger into the combustion chamber. While modern CCV systems are efficient, the filtration efficiency of CCV systems is limited to keep crankcase pressure below limits. Thus, some of the oil particles (mist) escape from the CCV system and accumulate on the turbocharger compressor and form soot-containing deposits in the compressor. This phenomenon results in significant degradation of turbocharger efficiency and thus higher fuel consumption and reduction of specific engine power. To measure the decrease in turbocharger efficiency and the consequent decrease in peak torque and fuel economy and increase in exhaust temperature, a Ford 6.7 liter V8 engine was used. A Ford 6.7 liter V8 engine is equipped with a direct injection common rail, exhaust gas recirculation, and variable geometry turbocharger, and rated peak torque at 1050lb-ft at 1800 rpm.

To determine changes in turbocharger efficiency and subsequent changes in fuel consumption, peak power, peak torque, exhaust temperature, and oil consumption, three-step tests were performed.

Step 1: fuel consumption and Power Scan at test initiation

At the beginning of the test, the engine is operated for power sweep and fuel efficiency testing. The fuel efficiency cycle is run as a discrete mode cycle using the EPA Supplemental Emission Test (SET) program. The SET cycle includes 13 mode steady state engine dynamometer testing. In each mode, the engine is run at a specific speed and load combination for a prescribed time and then moved to the next mode. The engine was cycled four times in 13 cycles and the average fuel consumption in grams per minute was measured for the four cycles.

The power sweep measures the torque (Nm) and power (KW) produced by a diesel engine at different engine speeds (rpm). Engine torque and power values are generated by connecting a dynamometer to the diesel engine and measuring the torque and power that the engine can produce at different speeds. For a given experiment, the engine was run at 1000rpm and the maximum torque value was recorded. The maximum torque at the next higher speed is measured thereafter. In a given experiment, torque and power values were recorded at engine speeds between 1000RPM and 3000RPM, in 100RPM increments. ford.6.7L engine is rated to produce peak torque at 1800rpm and peak power at 2800 rpm. The peak torque and peak power values were used to compare the lubricants of comparative example 1 and the present invention.

Step 2: turbocharger efficiency

The engine was operated near full load conditions targeting 3% soot generation at the end of 100 hours. During this phase, the temperature (T _in ) And pressure (P) _in ) And the temperature (T _out ) And pressure (P) _out ). These temperatures and pressures are used to calculate turbocharger efficiency using the following equations.

The cylinder outlet (exhaust) temperature is also measured. This stage is considered complete once the cylinder outlet temperature exceeds 800 ℃ (rated temperature of the turbocharger). At this point the turbocharger efficiency loss is noted. The point at which this increase in exhaust gas temperature occurs in the case of the comparative example 1 lubricant defines the test duration for the test of the inventive lubricant.

Step 3: fuel consumption and Power sweep step at test end

The lubricant of comparative example 1 was subjected to power sweep and fuel efficiency testing as described in step 1. The lubricants of the present invention were then tested following the procedure described in steps 1 to 3.

Turbocharger efficiency changes were measured throughout the test. To calculate the turbocharger efficiency loss, the measured turbocharger efficiency is compared to the turbocharger efficiency at the beginning of the test (when all engine components are clean). Table 3 summarizes the turbocharger efficiency losses for comparative example 1 and the lubricants of the present invention relative to the start of the test.

Similarly, the fuel efficiency change (%), peak power loss, peak torque loss, exhaust temperature increase were calculated by subtracting the values of each parameter at the end of the test and at the beginning of the test. Table 3 summarizes these parameters for comparative example 1 and the lubricants of the present invention.

As shown in table 3, the lubricant of the present invention exhibited less turbocharger efficiency loss, less fuel economy loss, less peak power loss, less peak torque loss, less exhaust gas temperature increase, and less total oil consumption than comparative example 1.

Claims

1.A lubricating composition comprising:

a. a base oil mixture having at least 25 wt% of a renewable base oil comprising a hydrocarbon mixture in which (a) the percentage of molecules having an even number of carbons according to FIMS is ≡80%; (b) BP/BI is more than or equal to-0.6037 (internal alkyl branch/molecule) +2.0; (c) has an average of 0.3 to 1.5 5 +methyl groups per molecule; and

b. an additive composition having a sulfur content of at most about 0.4 wt% and a sulfated ash content of at most about 0.5 wt% as determined by ASTM D874, and comprising: (a) At least one oil-soluble or dispersed oil-stable boron-containing compound having 400ppm to no more than 2000ppm boron, based on the total mass of the composition; (b) At least one oil-soluble or dispersed oil-stable molybdenum-containing compound having from about 700ppm molybdenum to no more than 1500ppm molybdenum, based on the total mass of the composition; wherein the lubricating oil composition has a sulfur to molybdenum ratio of from about 0.5:1 to less than or equal to about 4:1, and further wherein the lubricating oil composition is substantially free of zinc dialkyldithiophosphate. Wherein the total additive concentration ranges from about 20% to 30% and the base oil mixture is from about 70% to 80%.

2. The lubricating composition of claim 1, wherein the lubricating high temperature high shear viscosity is less than or equal to 3.2cP based on ASTM D5481.

3. The lubricating composition of claim 1, wherein the kinematic viscosity of lubrication at 100 ℃ is less than or equal to 12.5cSt based on ASTM D445.

4. The lubricating composition of claim 1, wherein the lubricating low temperature cold start viscosity is less than or equal to 7000mpa.s at-25 ℃ based on ASTM D5293.

5. The lubricating composition of claim 1, wherein the low temperature pumping viscosity is less than or equal to 60,000mpa.s at 30 ℃ without any yield stress, based on ASTM D4686.

6. A method of improving fuel economy retention, extending oil change cycles, and reducing oil consumption in an internal combustion engine using a lubricant comprising:

b. an additive composition having a sulfur content of at most about 0.4 wt% and a sulfated ash content of at most about 0.5 wt% as determined by ASTM D874, and comprising: (a) At least one oil-soluble or dispersed oil-stable boron-containing compound having 400ppm to no more than 2000ppm boron, based on the total mass of the composition; (b) At least one oil-soluble or dispersed oil-stable molybdenum-containing compound having from about 700ppm molybdenum to no more than 1500ppm molybdenum, based on the total mass of the composition; wherein the lubricating oil composition has a sulfur to molybdenum ratio of from about 0.5:1 to less than or equal to about 4:1, and further wherein the lubricating oil composition is substantially free of zinc dialkyldithiophosphate.

7. The method of claim 6 wherein fuel economy maintenance is improved by more than 0.2%.

8. The method of claim 7, wherein the internal combustion engine is a heavy duty diesel engine.

9. The method of claim 6, wherein the oil change period is extended by more than 30%.

10. The method of claim 9, wherein the internal combustion engine is a heavy duty diesel engine.

11. The method of claim 6, wherein the oil usage is reduced by more than 50%.

12. The method of claim 11, wherein the internal combustion engine is a heavy duty diesel engine.

13. A method for reducing fuel economy loss in an internal combustion engine to no more than 6% by supplying the composition of claim 1.

14. The method of claim 13, wherein the internal combustion engine is a medium duty diesel engine.

15. A method for reducing peak torque loss in an internal combustion engine to no more than 70Nm by supplying the composition of claim 1.

16. The method of claim 15, wherein the internal combustion engine is a medium duty diesel engine.

17. A method for reducing peak power loss in an internal combustion engine to no more than 20KW by supplying the composition of claim 1.

18. The method of claim 17, wherein the internal combustion engine is a medium duty diesel engine.

19. A method for reducing the rise in exhaust manifold temperature in an internal combustion engine to no more than 50 ℃ by supplying the composition of claim 1.

20. The method of claim 19, wherein the internal combustion engine is a medium duty diesel engine.

21. A method for reducing the amount of oil in an internal combustion engine to no more than 7500 grams by supplying the composition of claim 1.

22. The method of claim 21, wherein the internal combustion engine is a medium duty diesel engine.