EP4520807A1

EP4520807A1 - Detergent and dispersant systems for improved steel piston cleanliness in heavy duty lubricants

Info

Publication number: EP4520807A1
Application number: EP24194753.0A
Authority: EP
Inventors: Dominic Myers; Nicholas Giles; Peter Carress; Guillaume CARPENTIER; Paul Ransom; Leah Donham
Original assignee: Afton Chemical Corp
Current assignee: Afton Chemical Corp
Priority date: 2023-08-30
Filing date: 2024-08-15
Publication date: 2025-03-12
Also published as: JP2025036225A; CA3252657A1; MX2024010541A; JP7846174B2; CN119529930A; KR20250033086A

Abstract

The present disclosure relates to crankcase lubricating oil compositions, in particular heavy duty crankcase lubricating oil compositions, achieving high piston cleanliness of steel piston pursuant to the OM471 piston cleanliness test using a detergent system of sulfonate soap and dispersant system of one or more polyisobutylene succinimide dispersants to the lubricating oil composition.

Description

TECHNICAL FIELD

The present disclosure relates to lubricating compositions and, in particular, heavy duty lubricating compositions exhibiting improved piston cleanliness when used with steel pistons and with select detergent and dispersant systems.

BACKGROUND

Automotive manufacturers continue to push for improved efficiency, fluid longevity, and fuel economy, and as such, demands on engines, lubricants, and their components continue to increase. These requirements also mean engine oil performance must evolve to meet the higher demands of such modern engines and their corresponding performance criteria tied to their unique use and applications. With such exacting demands for engine oils, lubricant manufacturers often tailor lubricants and their additives to meet certain performance requirements for industry and/or manufacturer applications. Typically, industry standards and/or automotive manufacturers require certain performance standards such that a lubricant designed for one use or application may not satisfy all the performance specifications for a different use or application.
For example, detergent and dispersant choice in an engine oil formulation was often based on a number of factors, including but not limited to, piston cleanliness, acid neutralization, TBN retention, oxidation, low speed pre-ignition, wear, friction performance, fuel economy, supply, and/or cost factors to suggest but a few relevant considerations. However, it has previously been accepted that piston cleanliness in diesel engines typically required the use of detergent sources other than sulfonate; thus, diesel piston cleanliness generally required combinations of, for example, phenate and sulfonate detergents. These combinations tended to create formulation shortcomings by limiting the selection of supplementary componentry in the formulation and/or tended to cause formulation tradeoffs that could impact overall performance.
Prior heavy-duty engines (i.e., engines configured for vehicles having a gross vehicle weight of about 6,000 pounds or more) often used aluminum pistons and the prior phenate and sulfonate detergent systems were effective at maintaining piston cleanliness with such engine configuration. Previously, piston cleanliness for certain applications was evaluated pursuant to the OM501LA (CEC L-101-08) test using aluminum pistons. Recently, some heavy duty engines, engines configured for vehicles having a gross vehicle weight of about 6,000 pounds or more, have transitioned to the use of steel pistons permitting increased pressures and temperatures within the cylinders to aid in achieving improved fuel economy performance by generally having less friction, high torque management and/or long durability. However, with the transition to the upgraded engines and steel pistons, the industry has also developed a more demanding piston cleanliness test designated as the OM471 piston cleanliness test of CEC L-118-21. This test uses an engine having steel pistons and configured to deliver greater power and greater torque than the engine used in the OM501LA test. This new piston cleanliness test designed for steel pistons is not only more severe than the OM501LA test in terms of pressures and temperatures, but the test duration is also twice as long (about 600 hours instead of about 300 hours) and/or at higher maximum power and torque levels. The OM471 test produces a significantly increased engine power output of approximately 391 kW versus the OM501LA test which produces an engine power output of approximately 358 kW.
As such, heavy duty engine lubricants must now demonstrate passing performance when subjected to the more severe operating conditions of the new OM471 piston cleanliness test of CEC L-118-21. In many circumstances, however, varying components within a lubricant composition to satisfy newer performance characteristics tends to negatively impact one or more other performance characteristics Thus, it becomes challenging for the lubricant manufacturer to meet newer industry performance demands while also maintaining traditional fluid performance at the same time.

SUMMARY

In one approach or embodiment, the present disclosure relates to a method of lubricating a diesel engine, in particular a heavy-duty diesel engine, having steel pistons. The present inention is particularly suitable for lubricating engines having steel pistons, and specifically for lubricating heavy-duty diesel engines having steel pistons. In one aspect, the method includes lubricating the steel pistons of the diesel engine, in particular of the heavy-duty diesel engine, with a lubricating oil composition. In another aspect, the lubricating oil composition includes (i) a detergent system consisting of one or more alkaline earth metal sulfonate detergents delivering up to about 1 weight percent sulfonate soap to the lubricating oil composition (preferably, about 0.3 to about 1 weight percent sulfonate soap) and (ii) a dispersant system including one or more polyisobutylene succinimide dispersants delivering at least about 5 weight percent of the one or more dispersants to the lubricating oil composition; and wherein the one or more polyisobutylene succinimide dispersants are derived from a highly reactive polyisobutylene having a number average molecular weight of about 1,200 to about 2,500 and delivering more than 650 ppm nitrogen to the lubricating oil composition. In some embodiments, the diesel engine, in particular the heavy-duty diesel engine, is operated under conditions set forth in the OM471 Piston Cleanliness test of CEC L-118-21, which is in some embodiments for up to about 600 hours (or up to about 400 hours or about 400 to about 600 hours) and/or engine power output of up to approximately 391 kW. In some embodiments, the lubricating oil composition further includes an antioxidant system of one or more ashless antioxidants (preferably, an alkylated diphenylamine and a hindered phenol) and molybdenum containing antioxidants, wherein the molybdenum containing antioxidants including an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof and wherein the one or more ashless antioxidants are selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof and, in one embodiment, the lubricating compositions include at least about 2 weight percent, at least about 2.2 weight percent, or at least about 2.5 weight percent of the antioxidant system. In one approach, the antioxidant system may include at least 1.0 weight percent of diphenylamine, at least 1.0 weight percent hindered phenol, and less than 0.2 weight percent molybdenum-containing compounds in the lubricating composition.
In yet further approaches or embodiments, the method of lubricating a diesel engine, in particular a heavy-duty diesel engine, having steel pistons of the previous paragraph may include optional features, steps, or embodiments in any combination. These optional features, steps, or embodiments may include one or more of the following: wherein the diesel engine, in particular the heavy-duty diesel engine, is configured for powering a vehicle having a gross vehicle weight rating of about 6,000 pounds or higher; and/or wherein the detergent system consists of one or more overbased calcium sulfonate detergents and one or more low-based calcium sulfonate detergents, wherein an overbased detergent has a total base number (TBN) of at least about 200 mg KOH/g and a low-base detergent has a total base number (TBN) of about 175 mg KOH/g or less and with total base number (TBN) determined by ASTM D2896; and/or wherein the detergent system includes a weight ratio of the one or more overbased sulfonate detergents to the one or more low-based sulfonate detergents of about 3: 1 to about 8:1 (in other embodiments, about 3: 1 to about 6:1, about 3: 1 to about 5:1, or about 3:1 to about 4:1); and/or wherein the detergent system includes a weight ratio of overbased sulfonate soap to low-based sulfonate soap of about 2:1 to about 4:1 (in other embodiments, about 2.1: 1 to about 3.5:1, about 2.2:1 to about 3:1, or about 2.3:1 to about 2.8:1); and/or wherein the detergent system includes an effective amount of the one or more overbased sulfonate detergents to provide at least about 5 mg KOH/g to the detergent system and an effective amounts of the one or more low-based sulfonate detergents to provide about 25 to about 40 weight percent of the detergent soap; and/or wherein the detergent system consists essentially of calcium sulfonate detergents; and/or wherein the detergent system is substantially free of magnesium sulfonate detergents, substantially free of phenate detergents, or combinations thereof; and/or wherein the lubricating oil composition includes about 50 ppm to about 200 ppm molybdenum provided by an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof; and/or wherein the lubricating oil composition further includes about 0.5 to about 5 weight percent of one or more ashless antioxidants selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof; and/or wherein the lubricating oil composition includes up to about 1200 ppm of phosphorus from one or more metal dihydrocarbyl dithiophosphate compounds having hydrocarbyl groups derived from a mixture of linear or branched primary alcohols and linear or branched secondary alcohols; and/or wherein the heavy-duty crankcase lubricating composition has negligible amounts of magnesium such as about 20 ppm or less or about 10 ppm or less magnesium.
In yet other approaches or embodiments, the disclosure herein provides a crankcase lubricating oil composition, in particular a heavy-duty crankcase lubricating oil composition, suitable for a diesel engine having a gross vehicle weight of about 6,000 pounds or more and having an engine with steel pistons. In aspects of this embodiment, the crankcase lubricating oil composition, in particular the heavy-duty crankcase lubricating oil composition, includes one or more base oils of lubricating viscosity; a detergent system consisting of one or more alkaline earth metal sulfonate detergents delivering up to about 1 weight percent sulfonate soap to the lubricating oil composition (preferably, about 0.3 to about 1 weight percent of sulfonate soap); a dispersant system including one or more polyisobutylene succinimide dispersants delivering at least about 5 weight percent of the one or more dispersants to the lubricating oil composition; and wherein the one or more polyisobutylene succinimide dispersants are derived from a highly reactive polyisobutylene having a number average molecular weight of about 1,200 to about 2,500 and delivering more than 650 ppm nitrogen to the lubricating oil composition. In some embodiments, the diesel engine, in particular the heavy-duty diesel engine, is operated under conditions set forth in the OM471 Piston Cleanliness test of CEC L-118-21, which is in some embodiments for up to about 600 hours (or up to about 400 hours or about 400 to about 600 hours) and/or engine power output of up to approximately 391 kW. In some embodiments, the lubricating oil composition achieves a steel piston cleanliness rating of at least 90% (with higher percentage ratings being a cleaner piston) as measured by the OM471 Piston Cleanliness Test (CEC L-118-21). In other embodiments, the crankcase lubricating oil composition, in particular the heavy-duty crankcase lubricating oil composition, further includes an antioxidant system of one or more ashless antioxidants (preferably, an alkylated diphenylamine and a hindered phenol) and molybdenum containing antioxidants, wherein the molybdenum containing antioxidants including an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof and wherein the one or more ashless antioxidants are selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof and, in one embodiment, the lubricating compositions include at least about 2 weight percent, at least about 2.2 weight percent, or at least about 2.5 weight percent of the antioxidant system. In one approach, the antioxidant system may include at least 1.0 weight percent of diphenylamine, at least 1.0 weight percent hindered phenol, and less than 0.2 weight percent molybdenum-containing compounds in the lubricating composition.
In yet other approaches or embodiments, the crankcase lubricating oil, in particular the heavy-duty crankcase lubricating oil, described in the previous paragraph may include optional features or embodiments in any combination. These optional features or embodiment may include one or more of the following: wherein the detergent system consists of one or more overbased calcium sulfonate detergents and one or more low-based calcium sulfonate detergents, wherein an overbased detergent has a total base number (TBN) of at least about 200 mg KOH/g and a low-base detergent has a total base number (TBN) of about 175 mg KOH/g or less and with total base number (TBN) determined by ASTM D2896; and/or wherein the detergent system includes a weight ratio of the one or more overbased sulfonate detergents to the one or more low-based sulfonate detergents of about 3:1 to about 8:1 (in other embodiments, about 3:1 to about 6:1, about 3:1 to about 5:1, or about 3:1 to about 4:1); and/or wherein the detergent system includes a weight ratio of overbased sulfonate soap to low-based sulfonate soap of about 2:1 to about 4:1 (in other embodiments, about 2.1:1 to about 3.5:1, about 2.2:1 to about 3:1, or about 2.3:1 to about 2.8:1); and/or wherein the detergent system includes an effective amount of the one or more overbased sulfonate detergents to provide at least about 5 mg KOH/g to the detergent system and an effective amounts of the one or more low-based sulfonate detergents to provide about 25 to about 40 weight percent of the detergent soap; and/or wherein the detergent system consists essentially of calcium sulfonate detergents; and/or wherein the detergent system is substantially free of magnesium sulfonate detergents, substantially free of phenate detergents, or combinations thereof; and/or wherein the lubricating oil composition includes about 50 ppm to about 200 ppm molybdenum provided by an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof; and/or wherein the lubricating oil composition further includes about 0.5 to about 5 weight percent of one or more ashless antioxidants selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof; and/or wherein the lubricating oil composition includes up to about 1200 ppm of phosphorus from one or more metal dihydrocarbyl dithiophosphate compounds having hydrocarbyl groups derived from a mixture of linear or branched primary alcohols and linear or branched secondary alcohols; and/or wherein the heavy-duty crankcase lubricating oil composition includes negligible amounts of magnesium such as about 20 ppm or less or about 10ppm or less magnesium.
In yet further approaches or embodiments, the disclosure herein provides for the use of any embodiment of the lubricating oil composition, in particular of the heavy-duty lubricating oil composition, of this Summary for achieving improved steel piston cleanliness pursuant the OM471 Piston Cleanliness Test (CEC L-118-21), and in other embodiments, a steel piston cleanliness rating of at least about 90% as measured by OM471 Piston Cleanliness Test (CEC L-118-21).

DETAILED DESCRIPTION

The present disclosure in particular relates to heavy duty crankcase lubricating oil compositions and methods of lubricating a heavy duty diesel engine having steel pistons effective to achieve passing piston cleanliness pursuant to the new OM471 Piston Cleanliness test of CEC L-118-21 consistent with ACEA E8 specifications. In approaches or embodiments, the heavy duty lubricating oil compositions herein are suitable to achieve passing piston cleanliness on steel piston pursuant to OM471 testing. Such heavy duty diesel engines and the lubricants herein are configured for powering a vehicle having a gross vehicle weight rating of about 6,000 pounds or higher. Such engines often have 10 liter engine capacity or more, steel pistons, a maximum power of up to about 600 horsepower, a maximum torque of up to about 1,900 ft-lbs, and/or exhaust gas recirculation systems. The present invention is particularly suitable for lubricating engines having steel pistons, and more specifically for lubricating heavy-tudy diesel engines having steel pistons.
In approaches or embodiments herein, the crankcase lubricating oil compositions, in particular heavy-duty crankcase lubricating oil compositions, of this disclosure suitable for such engines and vehicles preferably includes at least (i) a detergent system comprising, consisting of, or consisting essentially of one or more alkaline earth metal sulfonate detergents delivering up to about 1 weight percent sulfonate soap to the lubricating oil composition; and (ii) a dispersant system including one or more polyisobutylene succinimide dispersants delivering at least about 5 weight percent of the one or more dispersants to the lubricating oil composition. In other approaches or embodiments, the lubricating oil compositions herein may also include one or more optional ashless antioxidants, one or more optional oil-soluble molybdenum compounds, and one or more optional metal dihydrocarbyl dithiophosphate compounds in amounts effective to aid in piston cleanliness in the harsh environments of the OM471 piston cleanliness test and when combined with the detergent and dispersant systems noted above. In some embodiments, the lubricating oil composition further includes an antioxidant system of the one or more ashless antioxidants (preferably, an alkylated diphenylamine and a hindered phenol) and the molybdenum containing antioxidants. The molybdenum containing antioxidants may include an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof. The one or more ashless antioxidants may be selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof. In one embodiment, the lubricating compositions include at least about 2 weight percent, at least about 2.2 weight percent, or at least about 2.5 weight percent of the antioxidant system and, in some embodiments, about 5 weight percent or less, about 4 weight percent or less, or about 3 weight percent or less of the antioxidant system. In one approach, the antioxidant system may include at least 1.0 weight percent of diphenylamine, at least 1.0 weight percent hindered phenol, and less than 0.2 weight percent molybdenum-containing compounds in the lubricating composition.
In some approaches, the one or more polyisobutylene succinimide dispersants of the dispersant system may be derived from a highly reactive polyisobutylene having a number average molecular weight of about 1,200 to about 2,500 and includes at least one borated polyisobutylene succinimide dispersant derived from a polyisobutylene having a number average molecular weight of about 1,000 to about 1,500 and delivering about 100 to about 200 ppm boron to the lubricating oil composition.
In other approaches or embodiments, the unique detergent systems herein provide a TBN from sulfonate detergents of about 3 to about 15 mg KOH/g, about 5 to about 15 mg KOH/g, or about 8 to about 15 mg KOH/g and comprise, consist of, or alternatively, consist essentially of calcium sulfonate detergents in amounts to provide the detergent system TBN and soap contents as discussed herein. In other words, the detergent systems herein are predominately sulfonate detergents, and most preferably, sulfonate-only detergents with little to no phenate or other detergent types (and most preferably, no phenate or other detergent additives) that was previously needed to pass prior heavy duty diesel piston cleanliness tests when using aluminum pistons. Even without detergent soap types outside of sulfonate, such as phenate soap, the lubricants herein surprisingly pass the more demanding OM471 piston cleanliness test and even when using steel pistons. The detergent systems herein are substantially free of non-sulfonate soaps, such as phenate soaps, which means about 25 percent or less of phenate soap, about 20 percent or less, about 15 percent or less, about 10 percent or less, about 5 percent or less, about 2.5 percent or less, about 1 percent or less, or no functional amounts of phenate soap.
As discussed more below, the detergent system herein may include a unique blend of overbased and neutral to low-based sulfonate detergents configured to provide the TBN levels and noted soap contents. In some approaches or embodiments, the detergent systems include a weight ratio of one or more overbased sulfonate detergents to one or more low-based sulfonate detergents of about 3:1 to about 8:1 (in other embodiments, about 3:1 to about 6:1, about 3:1 to about 5:1, or about 3:1 to about 4:1). In alternative approaches, the detergent system includes embodiments having a weight ratio of overbased sulfonate soap to low-based sulfonate soap of about 2:1 to about 4:1 (in other embodiments, about 2.1: 1 to about 3.5:1, about 2.2:1 to about 3:1, or about 2.3:1 to about 2.8:1). Preferably, the detergent system includes an effective amount of the one or more overbased sulfonate detergents to provide a minimum TBN of at least about 5 mg KOH/g to the detergent system and an effective amounts of the one or more low-based sulfonate detergents to provide about 25 to about 40 weight percent of detergent soap in the detergent system

The Detergent System

The lubricating compositions herein include detergent systems that achieve piston cleanliness pursuant to the demanding OM471 piston cleanliness test on steel pistons with little to no non-sulfonate soaps, such as phenate soap and, preferably no phenate soap. In some approaches, the steel piston cleanliness is achieved with a detergent system comprising, consisting of, or consisting essentially of one or more alkaline earth metal sulfonate detergents delivering up to about 1 weight percent soap to the lubricant and preferably up to 1 weight percent sulfonate soap with minimum TBN levels provided by the sulfonate detergents, which may be a blend of neutral, low-based, or overbased sulfonate detergents. Preferred TBN levels provided by the sulfonate detergents are at least about 3 mg KOH/g, at least about 4 mg KOH/g, at least about 5 mg KOH/g, at least about 3 mg KOH/g to about 15 mg KOH/g, at least about 5 mg KOH/g to about 9 mg KOH/g, about 12 mg KOH/g or less, about 10 mg KOH/g or less, or about 7 mg KOH/g or less. In embodiments, the detergent systems herein generally include one or more alkali or alkaline metal salts of sulfonates with minor amounts of, only residual levels of, or preferably no other functional detergent additives such as phenates, calixarates, salixarates, salicylates, carboxylic acids, sulfurized derivatives thereof, or combinations thereof so long as the minimum amounts of sulfonate soap, TBN levels, relationships of soap contents, and/or low levels of other detergents described herein are satisfied. In embodiments, therefore, the detergent systems herein include no more than about 0.5 weight percent, no more than about 0.2 weight percent, or no more than about 0.1 weight percent of non-sulfonate detergents.
Suitable detergents and their methods of preparation are described in greater detail in numerous patent publications, including US 7,732,390 and references cited therein, which are incorporated herein by reference. The lubricant compositions herein may include about 0.1 to about 5 weight percent of individual and/or total detergent additives, and in other approaches, about 0.15 to about 3 weight percent, and in yet other approaches, about 0.5 to 2.6 weight percent of individual and/or total detergent additives so long as the detergent additives meet the sulfonate amounts and other relationships noted herein.
As noted above and in some approaches, the detergent system provides select amounts of sulfonate soap and TBN levels with certain amounts of detergent metals. For instance, the detergent systems herein may provide an amount of total detergent metals that is greater than about 1200 ppm metal, or in other approaches, about 1200 ppm to about 3500 ppm total metal, about 1400 to about 3000 ppm total metal, or about 2000 ppm to about 2500 ppm total metals. In approaches, the detergent metals are calcium, magnesium, and/or sodium. In other approaches, the detergent metal is calcium and/or magnesium and in yet further, approaches the detergent metal is preferably only calcium.
Generally, suitable detergents in the system may include linear or branched alkali or alkaline earth metal salts, such as calcium, sodium, or magnesium, of petroleum sulfonic acids and long chain mono- or di-alkylaryl sulfonic acids with the aryl group being benzyl, tolyl, and xylyl and/or various phenates or derivatives of phenates. Examples of suitable detergents include, subject the required amounts of sulfonate soap noted above, low-based/neutral and overbased variations of the following detergents: calcium phenates, calcium sulfur containing phenates, calcium sulfonates, calcium calixarates, calcium salixarates, calcium salicylates, calcium carboxylic acids, calcium phosphorus acids, calcium mono- and/or di-thiophosphoric acids, calcium alkyl phenols, calcium sulfur coupled alkyl phenol compounds, calcium methylene bridged phenols, magnesium phenates, magnesium sulfur containing phenates, magnesium sulfonates, magnesium calixarates, magnesium salixarates, magnesium salicylates, magnesium carboxylic acids, magnesium phosphorus acids, magnesium mono- and/or di-thiophosphoric acids, magnesium alkyl phenols, magnesium sulfur coupled alkyl phenol compounds, magnesium methylene bridged phenols, sodium phenates, sodium sulfur containing phenates, sodium sulfonates, sodium calixarates, sodium salixarates, sodium salicylates, sodium carboxylic acids, sodium phosphorus acids, sodium mono- and/or di-thiophosphoric acids, sodium alkyl phenols, sodium sulfur coupled alkyl phenol compounds, or sodium methylene bridged phenols.
The detergent additives herein preferably include a blend of (i) effective amount of neutral to low-based detergents to provide a minimum soap content and (ii) effective amounts of overbased detergents to meet the minimum detergent TBN numbers.
As understood, overbased detergent additives are well-known in the art and may be alkali or alkaline earth metal overbased detergent additives. Such detergent additives may be prepared by reacting a metal oxide or metal hydroxide with a substrate and carbon dioxide gas. The substrate is typically an acid, for example, an acid such as an aliphatic substituted sulfonic acid, an aliphatic substituted carboxylic acid, or an aliphatic substituted phenol.
The term "overbased" relates to metal salts, such as metal salts of sulfonates, carboxylates, salicylates and/or phenates, wherein the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level in excess of 100% (i.e., they may comprise more than 100% of the theoretical amount of metal needed to convert the acid to its "normal," "neutral" salt). The expression "metal ratio," often abbreviated as MR, is used to designate the ratio of total chemical equivalents of metal in the overbased salt to chemical equivalents of the metal in a neutral salt according to known chemical reactivity and stoichiometry. In a normal or neutral salt, the MR is one and in an overbased salt, MR, is greater than one. They are commonly referred to as overbased, hyperbased, or superbased salts and may be salts of organic sulfur acids, carboxylic acids, or phenols.
As used herein, the term "TBN" is used to denote the Total Base Number in mg KOH/g as measured by the method of ASTM D2896. The detergent may be neutral or overbased. For example, a low-base or neutral detergent may have a total base number (TBN) of up to about 175 mg KOH/gram. In another example, an overbased detergent of the lubricating oil compositions herein may have a total base number (TBN) of about 200 mg KOH/gram or greater, or about 250 mg KOH/gram or greater, or about 350 mg KOH/gram or greater, or about 375 mg KOH/gram or greater, or about 400 mg KOH/gram or greater. The overbased detergent may have a metal to substrate ratio of from 1.1: 1 or less, or from 2:1 or less, or from 4:1 or less, or from 5:1 or less, or from 7:1 or less, or from 10:1 or less, or from 12:1 or less, or from 15:1 or less, or from 20:1 or less.
Examples of suitable overbased detergents (so long as the sulfonate soap and other TBN relationships noted herein are satisfied) include, but are not limited to, overbased calcium phenates, overbased calcium sulfur containing phenates, overbased calcium sulfonates, overbased calcium calixarates, overbased calcium salixarates, overbased calcium salicylates, overbased calcium carboxylic acids, overbased calcium phosphorus acids, overbased calcium mono- and/or di-thiophosphoric acids, overbased calcium alkyl phenols, overbased calcium sulfur coupled alkyl phenol compounds, overbased calcium methylene bridged phenols, overbased magnesium phenates, overbased magnesium sulfur containing phenates, overbased magnesium sulfonates, overbased magnesium calixarates, overbased magnesium salixarates, overbased magnesium salicylates, overbased magnesium carboxylic acids, overbased magnesium phosphorus acids, overbased magnesium mono- and/or di-thiophosphoric acids, overbased magnesium alkyl phenols, overbased magnesium sulfur coupled alkyl phenol compounds, or overbased magnesium methylene bridged phenols.
The low-based or neutral detergent generally has a TBN of up to 175 mg KOH/g, up to 150 mg KOH/g, up to 100 mg KOH/g, or up to 50 mg KOH/g. The low-based/neutral detergent may include a calcium-containing detergent. Examples of suitable low-based/neutral detergent (so long as the sulfonate soap and other TBN relationships noted herein are satisfied) include, but are not limited to, calcium sulfonates, calcium phenates, calcium salicylates, magnesium sulfonates, magnesium phenates, and/or magnesium salicylates.
In some embodiments, the detergent used in the lubricants herein include at least an overbased calcium sulfonate having a total base number of 200 to 400 and, in other approaches, about 250 to about 350. The above described TBN values reflect those of finished detergent components that have been diluted in a base oil. In some approaches, the detergent systems include a blend of neutral to low-based and overbased sulfonate detergents and the lubricants herein may include about 0.1 to about 1.0 weight percent of neutral to low-based sulfonate detergents and about 0.5 to about 3.0 weight percent of overbased sulfonate detergents (or in other approaches, about 1.0 to about 2.5 weight percent of overbased sulfonate detergents). In yet another approaches, the detergent systems herein may have a ratio of overbased sulfonate detergents to low-based sulfonate detergents of about 3:1 to about 8:1. As noted above, the overbased sulfonate detergent is in amounts effective to provide minimum TBN levels to the detergent and low-based or neutral sulfonate detergent is in amounts effective to provide minimum soap levels.
In other embodiments, the TBN of the detergents herein may reflect a neat or non-diluted version of the detergent component. For example, the fluids herein may include overbased calcium sulfonate as a neat additive having a TBN of about 500 to about 650, and in other approaches, about 550 to about 610. The fluids herein may also include neutral to low-based calcium sulfonate as a neat additive having a TBN of up to 75, up to 70, or about 40 to about 75, or about 40 to about 70.
More specifically, the detergent systems herein include neutral, low-based, and/or overbased detergents (preferably, neutral to overbased calcium sulfonates) to achieve a detergent TBN as measured by ASTM D2896 of at least about 3 mg KOH/g, at least about 4 mg KOH/g, at least about 5 mg KOH/g, at least about 3 mg KOH/g to about 15 mg KOH/g or less, about 5 mg KOH/g or less, or about 9 mg KOH/g or less. Preferably, the detergent systems herein include effective amounts of the one or more overbased sulfonate detergents to provide at least about 5 mg KOH/g to about 8 mg KOH/g to the detergent system's total TBN.
The detergent systems herein have high levels of sulfonate soap content relative to the total soap content, and in particular, the detergent systems have at least about 75 percent sulfonate soap, and in other approaches, at least about 80 percent sulfonate soap, at least about 85 sulfonate soap, at least about 90 percent sulfonate soap, at least about 95 sulfonate soap, at least about 98 percent sulfonate soap, at least about 99 percent sulfonate soap, or about 100 percent sulfonate soap (or any ranges therebetween). In other approaches, the soap amounts of the detergent are balanced with the select detergent TBN levels to achieve the steel piston cleanliness with little to no phenate detergents. In some approaches, the detergent systems of the lubricants, in particular heavy-duty lubricants, herein is substantially free of magnesium sulfonate detergents, substantially free of phenate detergents, or combinations thereof. As used herein, substantially free of means about 1 weight percent or less, 0.5 weight percent or less, about 0.25 weight percent or less, about 0.1 weight percent or less, or none.
In others approach, the detergent systems herein have a select weight ratio of sulfonate soap to phenate soap in the detergent system of about 75:25 or greater, about 80:20 or greater, about 85:15 or greater, about 90:10 or greater, even about 95:5, about 99:1 or greater (wherein greater in context of the ratio means more sulfonate soap relative to the phenate soap). Preferably, the detergent systems herein only include residual levels, if any, of phenate soap, salicylate soap, calixarate soap, or soaps other than sulfonate. Preferably, the detergent systems include effective amounts of the one or more low-based sulfonate detergents to provide about 30 to about 50 weight percent of the detergent soap.
Soap content generally refers to the amount of neutral organic acid salt and reflects a detergent's cleansing ability, or detergency, and dirt suspending ability. The soap content of a lubricant can be determined by ASTM D3712. A more detailed description of "soap content" is known to a person skilled in the art and explained in standard textbook entitled "Chemistry and Technology of Lubricants", Third Edition, Edited by R. M. Mortier and S. T. Orszulik, Copyright 2010, pages 219 to 220 under the sub-heading 7.2.5. Detergent Classification, which is incorporated herein by reference.

Dispersant System

The lubricating oil compositions, in particular heavy-duty crankcase lubricating oil compositions, herein also include a dispersant system including one or more polyisobutylene succinimide dispersants delivering at least about 5 weight percent, of the one or more dispersants to the lubricating oil composition (in other approaches, about 5 weight percent to about 15 weight percent, about 6 weight percent to about 12 weight percent, or about 6 weight percent to about 10 weight percent of the one or more dispersants). Preferably, the one or more polyisobutylene succinimide dispersants are derived from highly reactive polyisobutylene having a number average molecular weight of about 1,200 to about 2,500 and, in some embodiments, may also include at least one borated polyisobutylene succinimide dispersant derived from a highly reactive polyisobutylene having a number average molecular weight of about 1,000 to about 1,500 and delivering about 100 to about 200 ppm boron to the lubricating oil composition. In some embodiments, the dispersants deliver more than 650 ppm of nitrogen to the lubricating oil composition, and preferably, about 650 to about 1500 ppm of nitrogen. In some approaches or embodiments, the dispersants may be diluted with about 25 to about 50 weight percent of suitable process oil.
Dispersants are often known as ashless-type dispersants because, prior to mixing in a lubricating composition, they do not contain ash-forming metals and they do not normally contribute any ash when added to a lubricant. Ashless type dispersants are characterized by a polar group attached to a relatively high molecular weight hydrocarbon chain. Typical ashless dispersants include N-substituted long chain alkenyl succinimides. Examples of nitrogen-substituted long chain alkenyl succinimides include polyisobutylene succinimide with the number average molecular weight of the polyisobutylene substituent being in the range about 350 to about 5,000, or to about 3,000, or to about 2,000, or to about 1,500 as measured by GPC. Succinimide dispersants and their preparation are disclosed, for instance in US 7,897,696 or US 4,234,435 , which are incorporated herein by reference. The alkenyl substituent may be prepared from polymerizable monomers containing about 2 to about 16, or about 2 to about 8, or about 2 to about 6 carbon atoms. Succinimide dispersants are typically the imide formed from a polyamine, typically a poly(ethyleneamine).
In approaches, preferred amines for the dispersants may be selected from polyamines and hydroxylamines. Examples of polyamines that may be used include, but are not limited to, diethylene triamine (DETA), triethylene tetramine (TETA), tetraethylene pentamine (TEPA), and higher homologues such as pentaethylamine hexamine (PEHA), and the like. In some approaches, a so-called heavy polyamine may be used, which is a mixture of polyalkylene-polyamines comprising small amounts of lower polyamine oligomers such as TEPA and PEHA (pentaethylene hexamine) but primarily oligomers with 6 or more nitrogen atoms, 2 or more primary amines per molecule, and more extensive branching than conventional polyamine mixtures. A heavy polyamine preferably includes polyamine oligomers containing 7 or more nitrogen atoms per molecule and with 2 or more primary amines per molecule.
In some embodiments, polyisobutylene (PIB), when included, is a preferred reactant to form the dispersants and may have greater than 50 mol%, greater than 60 mol%, greater than 70 mol%, greater than 80 mol%, or greater than 90 mol% content of terminal double bonds. Such PIB is also referred to as highly reactive PIB ("HR-PIB"). HR-PIB having a number average molecular weight ranging from about 800 to about 5000, as determined by GPC, is suitable for use in embodiments of the present disclosure. Conventional PIB typically has less than 50 mol%, less than 40 mol%, less than 30 mol%, less than 20 mol%, or less than 10 mol% content of terminal double bonds.
An HR-PIB having a number average molecular weight ranging from about 900 to about 3,000 may be suitable, as determined by GPC. Such HR-PIB is commercially available, or can be synthesized by the polymerization of isobutene in the presence of a non-chlorinated catalyst such as boron trifluoride, as described in US 4,152,499 and/or US 5,739,355 . When used in the aforementioned thermal ene reaction, HR-PIB may lead to higher conversion rates in the reaction, as well as lower amounts of sediment formation, due to increased reactivity. A suitable method is described in U.S. Patent No. 7,897,696 . In one embodiment, the present disclosure further comprises at least one dispersant derived from polyisobutylene succinic anhydride ("PIBSA"). The PIB SA may have an average of between about 1.0 and about 2.0 succinic acid moieties per polymer.
In one embodiment, the dispersant may be derived from a polyalphaolefin (PAO) succinic anhydride. In one embodiment, the dispersant may be derived from olefin maleic anhydride copolymer. In another embodiment, the dispersant may be described as a poly-PIBSA. In an embodiment, the dispersant may be derived from an anhydride which is grafted to an ethylene-propylene copolymer.
A suitable class of nitrogen-containing dispersants may be derived from olefin copolymers (OCP), more specifically, ethylene-propylene dispersants which may be grafted with maleic anhydride. A more complete list of nitrogen-containing compounds that can be reacted with the functionalized OCP are described in U.S. Patent Nos. 7,485,603 ; 7,786,057 ; 7,253,231 ; 6,107,257 ; and 5,075,383 ; and/or are commercially available.
One class of suitable dispersants may also be Mannich bases. Mannich bases are materials that are formed by the condensation of a higher molecular weight, alkyl substituted phenol, a polyalkylene polyamine, and an aldehyde such as formaldehyde. Mannich bases are described in more detail in U.S. Patent No. 3,634,515 . A suitable class of dispersants may also be high molecular weight esters or half ester amides.
In some approaches, the dispersants in the lubricants herein may optionally be post-treated by conventional methods by a reaction with any of a variety of agents. Suitable post treat agents include boron, urea, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenolic esters, and phosphorus compounds. (See, e.g., US 7,645,726 ; US 7,214,649 ; US 8,048,831 ; and US 5,241,003 , which are all incorporated herein by reference in their entireties.)
The boron compound used as a post-treating reagent can be selected from boron oxide, boron halides, boron acids and esters of boron acids in an amount to provide from about 0.1 atomic proportion of boron for each mole of the nitrogen composition to about 20 atomic proportions of boron for each atomic proportion of nitrogen used. The dispersant post-treated with boron may contain from about 0.05 weight percent to about 2.0 weight percent, or in other approaches, about 0.5 weight percent to about 1.0 weight percent boron, based on the total weight of the borated dispersant.
In other approaches, carboxylic acid may also be used as a post-treating reagent and can be saturated or unsaturated mono-, di-, or poly-carboxylic acid. Examples of carboxylic acids include, but are not limited to, maleic acid, fumaric acid, succinic acid, and naphthalic diacid (e.g., 1,8-naphthalic diacid). Anhydrides can also be used as a post-treating reagent and can be selected from the group consisting of mono-unsaturated anhydride (e.g., maleic anhydride), alkyl or alkylene-substituted cyclic anhydrides (e.g., succinic anhydride or glutamic anhydride), and aromatic carboxylic anhydrides (including naphthalic anhydride, e.g., 1,8-naphthalic anhydride).
In one embodiment, the process of post-treating the dispersant includes first forming the succinimide product, as described above, and then further reacting the succinimide product with the post treating agent, such as a boron compound, such as boric acid. In some cases, the dispersants herein may be post-treated with more than one posttreatment agents. For example, the dispersant may be post-treated with a boron compound, such as boric acid, and also an anhydride, such as maleic anhydride. In some cases, the dispersant may be post-treated with an anhydride such as maleic anhydride and/or 1,8-naphthalic anhydride.
In addition to the above post-treatments the dispersant may be post-treated with a variety of post-treatments designed to improve or impart different properties. Such post-treatments include those summarized in columns 27-29 of U.S. Pat. No. 5,241,003 , hereby incorporated by reference. Such treatments include, treatment with: Inorganic phosphorous acids or anhydrates (e.g., U.S. Pat. Nos. 3,403,102 and 4,648,980 ); Organic phosphorous compounds (e.g., U.S. Pat. No. 3,502,677 ); Phosphorous pentasulfides; Boron compounds as already noted above (e.g., U.S. Pat. Nos. 3,178,663 and 4,652,387 ); Carboxylic acid, polycarboxylic acids, anhydrides and/or acid halides (e.g., U.S. Pat. Nos. 3,708,522 and 4,948,386 ); Epoxides polyepoxiates or thioexpoxides (e.g., U.S. Pat. Nos. 3,859,318 and 5,026,495 ); Aldehyde or ketone (e.g., U.S. Pat. No. 3,458,530 ); Carbon disulfide (e.g., U.S. Pat. No. 3,256,185 ); Glycidol (e.g., U.S. Pat. No. 4,617,137 ); Urea, thiourea or guanidine (e.g., U.S. Pat. Nos. 3,312,619 ; 3,865,813 ; and British Patent GB 1,065,595 ); Organic sulfonic acid (e.g., U.S. Pat. No. 3,189,544 and British Patent GB 2,140,811 ); Alkenyl cyanide (e.g., U.S. Pat. Nos. 3,278,550 and 3,366,569 ); Diketene (e.g., U.S. Pat. No. 3,546,243 ); A diisocyanate (e.g., U.S. Pat. No. 3,573,205 ); Alkane sultone (e.g., U.S. Pat. No. 3,749,695 ); 1,3-Dicarbonyl Compound (e.g., U.S. Pat. No. 4,579,675 ); Sulfate of alkoxylated alcohol or phenol (e.g., U.S. Pat. No. 3,954,639 ); Cyclic lactone (e.g., U.S. Pat. Nos. 4,617,138 ; 4,645,515 ; 4,668,246 ; 4,963,275 ; and 4,971,711 ); Cyclic carbonate or thiocarbonate linear monocarbonate or polycarbonate, or chloroformate (e.g., U.S. Pat. Nos. 4,612,132 ; 4,647,390 ; 4,648,886 ; 4,670,170 ); Nitrogen-containing carboxylic acid (e.g., U.S. Pat. 4,971,598 and British Patent GB 2,140,811 ); Hydroxy-protected chlorodicarbonyloxy compound (e.g., U.S. Pat. No. 4,614,522 ); Lactam, thiolactam, thiolactone or dithiolactone (e.g., U.S. Pat. Nos. 4,614,603 and 4,666,460 ); Cyclic carbonate or thiocarbonate, linear monocarbonate or polycarbonate, or chloroformate (e.g., U.S. Pat. Nos. 4,612,132 ; 4,647,390 ; 4,646,860 ; and 4,670,170 ); Nitrogen-containing carboxylic acid (e.g., U.S. Pat. No. 4,971,598 and British Patent GB 2,440,811 ); Hydroxy-protected chlorodicarbonyloxy compound (e.g., U.S. Pat. No. 4,614,522 ); Lactam, thiolactam, thiolactone or dithiolactone (e.g., U.S. Pat. Nos. 4,614,603 , and 4,666,460 ); Cyclic carbamate, cyclic thiocarbamate or cyclic dithiocarbamate (e.g., U.S. Pat. Nos. 4,663,062 and 4,666,459 ); Hydroxyaliphatic carboxylic acid (e.g., U.S. Pat. Nos. 4,482,464 ; 4,521,318 ; 4,713,189 ); Oxidizing agent (e.g., U.S. Pat. No. 4,379,064 ); Combination of phosphorus pentasulfide and a polyalkylene polyamine (e.g., U.S. Pat. No. 3,185,647 ); Combination of carboxylic acid or an aldehyde or ketone and sulfur or sulfur chloride (e.g., U.S. Pat. Nos. 3,390,086 ; 3,470,098 ); Combination of a hydrazine and carbon disulfide (e.g. U.S. Pat. No. 3,519,564 ); Combination of an aldehyde and a phenol (e.g., U.S. Pat. Nos. 3,649,229 ; 5,030,249 ; 5,039,307 ); Combination of an aldehyde and an O-diester of dithiophosphoric acid (e.g., U.S. Pat. No. 3,865,740 ); Combination of a hydroxyaliphatic carboxylic acid and a boric acid (e.g., U.S. Pat. No. 4,554,086 ); Combination of a hydroxyaliphatic carboxylic acid, then formaldehyde and a phenol (e.g., U.S. Pat. No. 4,636,322 ); Combination of a hydroxyaliphatic carboxylic acid and then an aliphatic dicarboxylic acid (e.g., U.S. Pat. No. 4,663,064 ); Combination of formaldehyde and a phenol and then glycolic acid (e.g., U.S. Pat. No. 4,699,724 ); Combination of a hydroxyaliphatic carboxylic acid or oxalic acid and then a diisocyanate (e.g. U.S. Pat. No.4,713,191 ); Combination of inorganic acid or anhydride of phosphorus or a partial or total sulfur analog thereof and a boron compound (e.g., U.S. Pat. No. 4,857,214 ); Combination of an organic diacid then an unsaturated fatty acid and then a nitrosoaromatic amine optionally followed by a boron compound and then a glycolating agent (e.g., U.S. Pat. No. 4,973,412 ); Combination of an aldehyde and a triazole (e.g., U.S. Pat. No. 4,963,278 ); Combination of an aldehyde and a triazole then a boron compound (e.g., U.S. Pat. No. 4,981,492 ); Combination of cyclic lactone and a boron compound (e.g., U.S. Pat. No. 4,963,275 and 4,971,711 ). The above-mentioned patents are herein incorporated in their entireties.
In other approaches, the total amount of dispersants in the dispersant system can be present in an amount up to about 15 weight percent of the lubricating composition and wherein one or more of the dispersants are post treated to provide at least about 40 ppm of boron and up to 300 ppm of boron to the lubricating composition (preferably, about 100 to about 200 ppm boron). In other approaches, the total amount of dispersants may be used in the lubricating composition in amounts from about 5 weight percent to about 15 weight percent, or about 6 weight percent to about 10 weight percent, about 7.0 weight percent to 10 weight percent, or about 7.0 weight percent to about 8 weight percent, based upon the final weight of the lubricating oil composition. As noted above, dispersants may be, in some approaches, diluted with about 25 to about 50 weight percent of process oil. Dispersants may provide at least about 400 ppm nitrogen and up to about 1,500 ppm nitrogen, preferably about 650 ppm to about 1500 ppm nitrogen, and more preferably, about 800 ppm to about 1200 ppm nitrogen.
The TBN of a suitable dispersant may be from about 10 to about 60 mg KOH/g dispersant, on an oil-free basis, which is comparable to about 5 to about 30 TBN if measured on a dispersant sample containing about 50% diluent oil. TBN is measured by the method of ASTM D2896.

Oil-soluble molybdenum compounds

The crankcase lubricants, in particular heavy duty crankcase lubricants, of the present disclosure may optionally include one or more oil-soluble molybdenum-containing compounds. An oil-soluble molybdenum compound may have the functional performance of an antiwear agent, an antioxidant, a friction modifier, or mixtures thereof. The oil-soluble molybdenum compound may be any of molybdenum dithiocarbamates, molybdenum dialkyl dithiophosphates, molybdenum sulfides, molybdenum disulfides, molybdenum dithiophosphinates, amine salts of molybdenum compounds, molybdenum xanthates, molybdenum thioxanthates, molybdenum sulfides, molybdenum carboxylates, molybdenum alkoxides, a trinuclear organo-molybdenum compound, and/or mixtures thereof. The molybdenum-containing compounds may be sulfur-containing or sulfur-free compounds. The molybdenum disulfide may be in the form of a stable dispersion.
In one embodiment, the oil-soluble molybdenum compound may be selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, and mixtures thereof. In one embodiment, the oil-soluble molybdenum compound may be a molybdenum dithiocarbamate. Exemplary sulfur-free organomolybdenum complexes of organic amides are disclosed in US 5,137,647 .
In one approach or embodiment, suitable molybdenum dithiocarbamates may be represented by the Formula:
where R⁵, R⁶, R⁷, and R⁸ are each, independently, a hydrogen atom, a C₁ to C₂₀ alkyl group, a C₆ to C₂₀ cycloalkyl, aryl, alkylaryl, or aralkyl group, or a C₃ to C₂₀ hydrocarbyl group optionally containing an ester, ether, alcohol, or carboxyl group; and X₁, X₂, Y₁, and Y₂ are each, independently, a sulfur or oxygen atom. Examples of suitable groups for each of R⁵, R⁶, R⁷, and R⁸ include 2-ethylhexyl, nonylphenyl, methyl, ethyl, n-propyl, iso-propyl, n-butyl, t-butyl, n-hexyl, n-octyl, nonyl, decyl, dodecyl, tridecyl, lauryl, oleyl, linoleyl, cyclohexyl and phenylmethyl. In other approaches, R⁵, R⁶, R⁷, and R⁸ may each have C₆ to C₁₈ alkyl groups. X₁ and X₂ may be the same, and Y₁ and Y₂ may be the same. X₁ and X₂ may both comprise sulfur atoms, and Y₁ and Y₂ may both comprise oxygen atoms. Further examples of molybdenum dithiocarbamates include C₆-C₁₈ dialkyl or diaryldithiocarbamates, or alkyl-aryldithiocarbamates such as dibutyl-, diamyl-di-(2-ethylhexyl)-, dilauryl-, dioleyl-, and dicyclohexyl-dithiocarbamate.
Suitable examples of molybdenum compounds which may be used include commercial materials sold under the trade names such as Molyvan^® 822, Molyvan^® A, Molyvan^® 2000, Molyvan^® 807, Molyvan^® 855, and Molyvan^® 1055 from R. T. Vanderbilt Co., Ltd., and Sakura-Lube^™ S-165, S-200, S-300, S-310G, S-525, S-600, S-700, and S-710 available from Adeka Corporation, and mixtures thereof. Suitable molybdenum components are described in U.S. Pat. Nos. 5,650,381 ; RE 37,363 E1 ; RE 38,929 E1 ; and RE 40,595 E1 , incorporated herein by reference in their entireties.
In one embodiment, and if included in the formulations, the oil-soluble molybdenum compound may be present in the crankcase lubricants, in particular heavy duty crankcase lubricants, herein in an amount to provide up to about 800 ppm of molybdenum, or about 5 ppm to 800 ppm molybdenum. In other embodiments, the oil-soluble molybdenum compound may be present in an amount to provide about 10 to about 500 ppm molybdenum, about 20 to 250 ppm molybdenum, about 30 to 175 ppm molybdenum, about 40 to 150 ppm molybdenum, about 50 to 125 ppm molybdenum, or about 60 to 100 ppm molybdenum.

Antioxidant

The crankcase lubricants, in particular heavy duty crankcase lubricants, herein may also include one or more antioxidants and, preferably, one or more aminic antioxidants. If used, the antioxidants may be provided in amounts of about 1 to about 5 weight percent (in other approaches, about 1.2 to about 4 weight percent or about 1.4 to about 3 weight percent, or about 2 to about 3 weight percent), which may aid in piston cleanliness on steel pistons in the hard environments of the OM471 test when combined with the dispersant and detergent systems herein.
Suitable antioxidants may include, for example, phenates, phenate sulfides, sulfurized olefins, phosphosulfurized terpenes, sulfurized esters, aromatic amines, alkylated diphenylamines (e.g., nonyl diphenylamine, di-nonyl diphenylamine, octyl diphenylamine, di-octyl diphenylamine), phenyl-alpha-naphthylamines, alkylated phenyl-alpha-naphthylamines, hindered non-aromatic amines, phenols, hindered phenols, oil-soluble molybdenum compounds, macromolecular antioxidants, or mixtures thereof. Antioxidant compounds may be used alone or in combination.
In some approaches or embodiments, suitable aminic antioxidants may include, but are not limited to, antioxidants selected from aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines, and the like, or combinations thereof. The total amount of antioxidant in the lubricating compositions herein may be present in an amount to deliver up to about 400 ppm nitrogen, or up to about 300 ppm nitrogen, or up to about 200 ppm nitrogen, or about 50 to about 400 ppm nitrogen, about 60 to about 300 ppm nitrogen, about 70 to about 200 ppm nitrogen, or about 80 to about 100 ppm nitrogen. In other approaches, the lubricating compositions herein may include up to about 5 weight percent of the aminic antioxidant, or about 0.1 to about 5 weight percent of the aminic antioxidant, in other approaches, about 0.2 to about 3 weight percent, or about 0.2 to about 2.0 weight percent of the aminic antioxidant.
In some approaches, the aminic antioxidant may be one or more aromatic amine antioxidants and may include, but are not limited to, diarylamines having the formula:
wherein R' and R" each independently represents a substituted or unsubstituted aryl group having from 6 to 30 carbon atoms. If substituted, suitable substituents for the aryl group of R' and R" include aliphatic hydrocarbon groups such as alkyl having from 1 to 30 carbon atoms, hydroxy groups, halogen radicals, carboxylic acid or ester groups, or nitro groups. The aryl group may be substituted or unsubstituted phenyl or naphthyl, particularly wherein one or both of the aryl groups are substituted with at least one alkyl having from 4 to 30 carbon atoms, preferably from 4 to 18 carbon atoms, most preferably from 4 to 9 carbon atoms. In approaches, one or both aryl groups may be substituted, e.g. mono-alkylated diphenylamine, di-alkylated diphenylamine, C9 alkylated diphenyl amines, or mixtures of mono- and di-alkylated diphenylamines.
Examples of diarylamines that may be used include, but are not limited to: diphenylamine; various alkylated diphenylamines, 3-hydroxydiphenylamine, N-phenyl-1,2-phenylenediamine, N-phenyl-1,4-phenylenediamine, monobutyldiphenyl-amine, dibutyl-diphenylamine, monooctyldiphenylamine, dioctyldiphenylamine, monononyl-diphenylamine, dinonyldiphenylamine, monotetradecyldiphenylamine, ditetradecyl-diphenylamine, phenyl-alpha-naphthylamine, monooctyl phenyl-alpha-naphthylamine, phenyl-beta-naphthylamine, monoheptyldiphenylamine, diheptyl-diphenylamine, p-oriented styrenated diphenylamine, mixed butyloctyldiphenylamine, and mixed octylstyryl-diphenylamine.
In other approaches, suitable antioxidants may include aromatic amine antioxidants. Examples of phenolic antioxidants include N,N'-di-sec-butyl-phenylenediamine, 4-iisopropylamino diphenylamine, phenyl-alpha-naphthyl amine, phenyl-alpha-naphthyl amine, and ring-alkylated diphenylamines.
The hindered phenol antioxidant may contain a secondary butyl and/or a tertiary butyl group as a sterically hindering group. The phenol group may be further substituted with a hydrocarbyl group and/or a bridging group linking to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or 4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol. In one embodiment the hindered phenol antioxidant may be an ester and may include, e.g., Irganox^™ L-135 available from BASF or an addition product derived from 2,6-di-tert-butylphenol and an alkyl acrylate, wherein the alkyl group may contain about 1 to about 18, or about 2 to about 12, or about 2 to about 8, or about 2 to about 6, or about 4 carbon atoms. Another commercially available hindered phenol antioxidant may be an ester and may include Ethanox^™ 4716 available from Albemarle Corporation.
Useful antioxidants may include diarylamines and high molecular weight phenols. In an embodiment, the lubricating oil composition may contain a mixture of a diarylamine and a high molecular weight phenol, such that each antioxidant may be present in an amount sufficient to provide up to about 5%, by weight, based upon the final weight of the lubricating oil composition. In an embodiment, the antioxidant may be a mixture of about 0.3 to about 1.5% diarylamine and about 0.4 to about 2.5% high molecular weight phenol, by weight, based upon the final weight of the lubricating oil composition.
Examples of suitable olefins that may be sulfurized to form a sulfurized olefin include propylene, butylene, isobutylene, polyisobutylene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene, eicosene or mixtures thereof. In one embodiment, hexadecene, heptadecene, octadecene, nonadecene, eicosene or mixtures thereof and their dimers, trimers and tetramers are especially useful olefins. Alternatively, the olefin may be a Diels-Alder adduct of a diene such as 1,3-butadiene and an unsaturated ester, such as, butyl acrylate.
Another class of sulfurized olefin includes sulfurized fatty acids and their esters. The fatty acids are often obtained from vegetable oil or animal oil and typically contain about 4 to about 22 carbon atoms. Examples of suitable fatty acids and their esters include triglycerides, oleic acid, linoleic acid, palmitoleic acid or mixtures thereof. Often, the fatty acids are obtained from lard oil, tall oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil or mixtures thereof. Fatty acids and/or ester may be mixed with olefins, such as α-olefins.

Metal Dihydrocarbyl Dithiophosphate Compounds

The cranckcase lubricants, in particular heavy-duty crankcase lubricants, herein may optionally include one or more metal dihydrocarbyl dithiophosphate compounds, such as but not limited to, a zinc dihydrocarbyl dithiophosphate compound (ZDDP). If used, the one or more metal dihydrocarbyl dithiophosphate compounds may provide at least about 500 ppm of phosphorus to the lubricant, in oarticular heavy duty lubricant, in other approaches, about 600 ppm to about 1200 ppm phosphorus, or about 700 ppm to about 1,000 ppm phosphorus, or about 700 ppm to about 1,200 ppm phosphorus. If used herein, the metal dihydrocarbyl dithiophosphate compounds preferably include hydrocarbyl groups derived form a mixture of primary and secondary alcohols.
Suitable metal dihydrocarbyl dithiophosphates compounds may include between 5 to about 10 weight percent metal (such as, about 6 to about 9 weight percent metal such as zinc), and about 8 to about 18 weight percent sulfur, (such as about 12 to about 18 weight percent sulfur, or about 8 to about 15 weight percent sulfur). Suitable metal dihydrocarbyl dithiophosphate compounds may comprise dihydrocarbyl dithiophosphate metal salts wherein the metal may be an alkali metal, alkaline earth metal, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, zirconium, zinc, or combinations thereof. Preferably, the metal is zinc.
The alkyl groups on the metal dihydrocarbyl dithiophosphate compounds herein may be derived from primary alcohols, secondary alcohols, phenols, and/or mixtures thereof and preferably mixtures of primary and secondary alcohols. For example, all of the alkyl or hydrocarbyl groups of metal dihydrocarbyl dithiophosphate compounds herein may be derived from a primary alcohol (such as 2-ethylhexyl alcohol) and/or from a mixture of primary and secondary alcohols (such as 2-ethyl hexanol, isobutanol, and isopropanol for instance). For example and in one embodiment, about 60 mol percent or more of the alkyl groups are derived from the primary alcohols of 2-ethyl hexanol and/or isobutyl alcohol and about 40 mol percent or less of the alkyl groups are derived from a secondary alcohol (such as isopropyl alcohol, methyl isobutyl carbinol, and the like, and/or combinations thereof). In optional embodiments, all of the alkyl groups on the metal dihydrocarbyl dithiophosphate compounds may be derived from a primary alcohol, such as 2-ethyl hexanol or others noted below. Preferably, the metal dihydrocarbyl dithiophosphate compounds is ZDDP obtained from 60 to 80 mol percent 2-ethyl hexanol and/or isobutyl alcohol and 20 to 40 mol percent of isopropyl alcohol and may include about 6 to about 10 weight percent phosphorus, about 7 to about 9 weight percent zinc, and about 15 to about 20 weight percent sulfur.
The metal dihydrocarbyl dithiophosphate compounds herein may be derived from, but not limited to, alcohols selected from 2-ethylhexanol, methylheptanol, heptanol, octanol, nonanol, decanol, dodecanol, and/or iso-variants thereof. Examples of suitable metal dihydrocarbyl dithiophosphate compounds include, but are not limited, to: zinc O,O-di(C_8-14-alkyl)dithiophosphate; zinc O,O-bis(2-ethylhexyl) dithiophosphate; zinc O,O-diisooctyl dithiophosphate; zinc O,O-bis(dodecylphenyl) dithiophosphate; zinc O,O-diisodecyl dithiophosphate; zinc O,O-bis(6-methylheptyl) dithiophosphate; zinc O,O-dioctyl dithiophosphate; zinc O,O-dipentyl dithiophosphate; zinc O-(2-methylbutyl)-O-(2-methylpropyl)dithiophosphate; and zinc O-(3-methylbutyl)-O-(2-methylpropyl) dithiophosphate, or combinations thereof.
In approaches or embodiments, the metal dihydrocarbyl dithiophosphate compound suitable for heavy duty crankcase lubricants herein may have a structure of Formula I:
wherein each R in Formula I independently contains from 6 to 18 carbon atoms, or 6 to 12 carbon atoms, or about 8 to 10 carbon atoms so long as each phosphorus atom has, on average, at least 14 total carbons, and preferably at least 8 total carbons or 8 to 16 total carbons per phosphorus atom. For example, each R may independently be ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl, propenyl, butenyl. The number of carbon atoms in each R group in the formula above will generally be about 3 or greater, about 4 or greater, about 6 or greater, or about 8 or greater. Each R group may average 6 to 10 carbons and, preferably 8 to 10 carbons. Preferably, each R may be linear or branched C8 or 2-ethylhexyl groups, C3 or isopropyl groups, and/or C4 or isobutyl groups. In Formula I, A is a metal, such as aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, zirconium, zinc, or combinations thereof and, preferably, A is zinc. When the metal dihydrocarbyl dithiophosphate compound has the structure shown in Formula I and with A being zinc, the compound may have about 6 to about 9 weight percent phosphorus and about 7 to about 9 weight percent zinc and a zinc to phosphorus ratio of about 1.0 to about 1.5 In some approaches or embodiments, it is understood in the art that a more accurate representation of the sulfur-zinc coordination arrangement may be represented by the symmetrical arrangement shown below with the chemical structure of Formula II that may be used herein as interchangeable with Formula I shown above. It is also understood that the structures shown in Formulas I and II may be present as monomer, dimer, trimer, or oligomer (such as a tetramer).
Dihydrocarbyl dithiophosphate metal salts may be prepared in accordance with known techniques by first forming a dihydrocarbyl dithiophosphoric acid (DDPA), usually by reaction of one or more alcohols or phenols with P₂S₅ and then neutralizing the formed DDPA with a metal compound, such as zinc oxide. For example, DDPA may be made by reacting mixtures of alcohols including the suitable amounts of primary alcohols (and if needed, suitable blends of primary and secondary alcohols) with P₂S₅. In this case, the DDPA includes alkyl groups predominately derived from primary alcohols or both primary and secondary alcohols as needed to meet the required primary alcohol content in the final product. Alternatively, multiple DDPAs can be prepared where the alkyl groups on one DDPA are derived entirely from secondary alcohols and the alkyl groups on another DDPA are derived entirely from primary alcohols. The DDPAs are then blended together to form a mixture of DDPAs having alkyl groups meeting the noted primary alcohol content.

Base Oil or Base Oil Blend:

The base oil used in the crankcase lubricating oil compositions, in particular heavy duty crankcase lubricating oil compositions, herein may be oils of lubricating viscosity and selected from any of the base oils in API Groups I to V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. Heavy duty crankcase lubricants may have a kV100 of about 9 to about 20 cSt (ASTM D445). In some cases, even lower viscosity is targeted and the crankcase lubricants, in particular heavy duty crankcase lubricants, have a kV100 of about 5 to about 9 cSt (ASTM D445). The five base oil groups are generally set forth in Table 1 below:

Table 1

Base oil Category	Sulfur (%)		Saturates (%)	Viscosity Index
Group I	> 0.03	and/or	<90	80 to 120
Group II	≤0.03	and	≥90	80 to 120
Group III	≤0.03	and	≥90	≥120
Group IV	All polyalphaolefins (PAOs)
Group V	All others not included in Groups I, II, III, or IV

Groups I, II, and III are mineral oil process stocks. Group IV base oils contain true synthetic molecular species, which are produced by polymerization of olefinic unsaturated hydrocarbons. Many Group V base oils are also true synthetic products and may include diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphate esters, polyvinyl ethers, and/or polyphenyl ethers, and the like, but may also be naturally occurring oils, such as vegetable oils. It should be noted that although Group III base oils are derived from mineral oil, the rigorous processing that these fluids undergo causes their physical properties to be very similar to some true synthetics, such as PAOs. Therefore, oils derived from Group III base oils may be referred to as synthetic fluids in the industry. Group II+ may comprise high viscosity index Group II.
The base oil blend used in the disclosed lubricating oil composition may be a mineral oil, animal oil, vegetable oil, synthetic oil, synthetic oil blends, or mixtures thereof. Suitable oils may be derived from hydrocracking, hydrogenation, hydrofinishing, unrefined, refined, and re-refined oils, and mixtures thereof.
Unrefined oils are those derived from a natural, mineral, or synthetic source without or with little further purification treatment. Refined oils are similar to the unrefined oils except that they have been treated in one or more purification steps, which may result in the improvement of one or more properties. Examples of suitable purification techniques are solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, and the like. Oils refined to the quality of an edible may or may not be useful. Edible oils may also be called white oils. In some embodiments, lubricating oil compositions are free of edible or white oils.
Re-refined oils are also known as reclaimed or reprocessed oils. These oils are obtained similarly to refined oils using the same or similar processes. Often these oils are additionally processed by techniques directed to removal of spent additives and oil breakdown products.
Mineral oils may include oils obtained by drilling or from plants and animals or any mixtures thereof. For example such oils may include, but are not limited to, castor oil, lard oil, olive oil, peanut oil, corn oil, soybean oil, and linseed oil, as well as mineral lubricating oils, such as liquid petroleum oils and solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Such oils may be partially or fully hydrogenated, if desired. Oils derived from coal or shale may also be useful.
Useful synthetic lubricating oils may include hydrocarbon oils such as polymerized, oligomerized, or interpolymerized olefins (e.g., polybutylenes, polypropylenes, propyleneisobutylene copolymers); poly(1-hexenes), poly(1-octenes), trimers or oligomers of 1-decene, e.g., poly(1-decenes), such materials being often referred to as α-olefins, and mixtures thereof; alkyl-benzenes (e.g. dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls); diphenyl alkanes, alkylated diphenyl alkanes, alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof or mixtures thereof. Polyalphaolefins are typically hydrogenated materials.
Other synthetic lubricating oils include polyol esters, diesters, liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, and the diethyl ester of decane phosphonic acid), or polymeric tetrahydrofurans. Synthetic oils may be produced by Fischer-Tropsch reactions and typically may be hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment oils may be prepared by a Fischer-Tropsch gas-to-liquid synthetic procedure as well as other gas-to-liquid oils.
The major amount of base oil included in a lubricating composition may be selected from the group consisting of Group I, Group II, a Group III, a Group IV, a Group V, and a combination of two or more of the foregoing, and wherein the major amount of base oil is other than base oils that arise from provision of additive components or viscosity index improvers in the composition. In another embodiment, the major amount of base oil included in a lubricating composition may be selected from the group consisting of Group II, a Group III, a Group IV, a Group V, and a combination of two or more of the foregoing, and wherein the major amount of base oil is other than base oils that arise from provision of additive components or viscosity index improvers in the composition.
The amount of the oil of lubricating viscosity present may be the balance remaining after subtracting from 100 wt% the sum of the amount of the performance additives inclusive of viscosity index improver(s) and/or pour point depressant(s) and/or other top treat additives. For example, the oil of lubricating viscosity that may be present in a finished fluid may be a major amount, such as greater than about 50 wt%, greater than about 60 wt%, greater than about 70 wt%, greater than about 80 wt%, greater than about 85 wt%, or greater than about 90 wt%.
The base oil systems herein, in some approaches or embodiments, include one or more of a Group I to Group V base oils and may have a KV100 of about 2 to about 20 cSt, in other approaches, about 2 to about 10 cSt, about 2.5 to about 6 cSt, in yet other approaches, about 2.5 to about 3.5 cSt, and in other approaches about 2.5 to about 4.5 cSt. As used herein, the terms "oil composition," "lubrication composition," "lubricating oil composition," "lubricating oil," "lubricant composition," "fully formulated lubricant composition," "lubricant," and "lubricating and cooling fluid" are considered synonymous, fully interchangeable terminology referring to the finished lubrication product comprising a major amount of a base oil component plus minor amounts of the detergents and the other optional components.

Optional Additives:

The lubricating oil compositions, in particular heavy duty lubricating oil compositions, herein may also include a number of optional additives combined with the detergent systems and dispersant system discussed above and as needed to meet performance standards. Those optional additives are described in the following paragraphs.
Antiwear Agents: The lubricating oil compositions herein also may optionally contain additional antiwear agents. Examples of suitable antiwear agents include, but are not limited to, a metal thiophosphate; a metal dialkyldithiophosphate; a phosphoric acid ester or salt thereof; a phosphate ester(s); a phosphite; a phosphorus-containing carboxylic ester, ether, or amide; a sulfurized olefin; thiocarbamate-containing compounds including, thiocarbamate esters, alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl)disulfides; and mixtures thereof. A suitable antiwear agent may be a molybdenum dithiocarbamate. The phosphorus containing antiwear agents are more fully described in European Patent 612 839 . The metal in the dialkyl dithio phosphate salts may be an alkali metal, alkaline earth metal, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, or zinc. A useful antiwear agent may be zinc dialkyldithiophosphate.
Further examples of suitable additional antiwear agents include titanium compounds, tartrates, tartrimides, oil soluble amine salts of phosphorus compounds, sulfurized olefins, phosphites (such as dibutyl phosphite), phosphonates, thiocarbamate-containing compounds, such as thiocarbamate esters, thiocarbamate amides, thiocarbamic ethers, alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides. The tartrate or tartrimide may contain alkyl-ester groups, where the sum of carbon atoms on the alkyl groups may be at least 8. The antiwear agent may in one embodiment include a citrate.
The additional antiwear agent may be present in ranges including about 0 wt% to about 15 wt%, or about 0.01 wt% to about 10 wt%, or about 0.05 wt% to about 5 wt%, or about 0.1 wt% to about 3 wt% of the lubricating oil composition.
Boron-Containing Compounds: The lubricating oil compositions herein may optionally contain one or more boron-containing compounds. Examples of boron-containing compounds include borate esters, borated fatty amines, borated epoxides, borated detergents, dispersed hydrated sodium or potassium borates, and borated dispersants, such as borated succinimide dispersants, as disclosed in U.S. Patent No. 5,883,057 . The boron-containing compound, if present, can be used in an amount sufficient to provide up to about 8 wt%, about 0.01 wt% to about 7 wt%, about 0.05 wt% to about 5 wt%, or about 0.1 wt% to about 3 wt% of the lubricating oil composition.
Additional Detergents: The lubricating oil composition may optionally further comprise one or more neutral, low based, or overbased detergents, and mixtures thereof. Suitable detergent substrates include phenates, sulfur containing phenates, sulfonates, calixarates, salixarates, salicylates, carboxylic acids, phosphorus acids, mono- and/or di-thiophosphoric acids, alkyl phenols, sulfur coupled alkyl phenol compounds, or methylene bridged phenols. Suitable detergents and their methods of preparation are described in greater detail in numerous patent publications, including US 7,732,390 and references cited therein.
The detergent substrate may be salted with an alkali or alkaline earth metal such as, but not limited to, calcium, magnesium, potassium, sodium, lithium, barium, or mixtures thereof. In some embodiments, the detergent is free of barium. In some embodiments, a detergent may contain traces of other metals such as magnesium or calcium in amounts such as 50ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less. A suitable detergent may include alkali or alkaline earth metal salts of petroleum sulfonic acids and long chain mono- or di-alkylarylsulfonic acids with the aryl group being benzyl, tolyl, and xylyl. Examples of suitable detergents include, but are not limited to, calcium phenates, calcium sulfur containing phenates, calcium sulfonates, calcium calixarates, calcium salixarates, calcium salicylates, calcium carboxylic acids, calcium phosphorus acids, calcium mono- and/or di-thiophosphoric acids, calcium alkyl phenols, calcium sulfur coupled alkyl phenol compounds, calcium methylene bridged phenols, magnesium phenates, magnesium sulfur containing phenates, magnesium sulfonates, magnesium calixarates, magnesium salixarates, magnesium salicylates, magnesium carboxylic acids, magnesium phosphorus acids, magnesium mono- and/or di-thiophosphoric acids, magnesium alkyl phenols, magnesium sulfur coupled alkyl phenol compounds, magnesium methylene bridged phenols, sodium phenates, sodium sulfur containing phenates, sodium sulfonates, sodium calixarates, sodium salixarates, sodium salicylates, sodium carboxylic acids, sodium phosphorus acids, sodium mono- and/or di-thiophosphoric acids, sodium alkyl phenols, sodium sulfur coupled alkyl phenol compounds, or sodium methylene bridged phenols.
Overbased detergent additives are well known in the art and may be alkali or alkaline earth metal overbased detergent additives. Such detergent additives may be prepared by reacting a metal oxide or metal hydroxide with a substrate and carbon dioxide gas. The substrate is typically an acid, for example, an acid such as an aliphatic substituted sulfonic acid, an aliphatic substituted carboxylic acid, or an aliphatic substituted phenol.
An overbased detergent of the lubricating oil composition may have a total base number (TBN) of about 200 mg KOH/g or greater, or as further examples, about 250 mg KOH/g or greater, or about 350 mg KOH/g or greater, or about 375 mg KOH/g or greater, or about 400 mg KOH/g or greater. The TBN being measured by the method of ASTM D2896.
Examples of suitable overbased detergents include, but are not limited to, overbased calcium phenates, overbased calcium sulfur containing phenates, overbased calcium sulfonates, overbased calcium calixarates, overbased calcium salixarates, overbased calcium salicylates, overbased calcium carboxylic acids, overbased calcium phosphorus acids, overbased calcium mono- and/or di-thiophosphoric acids, overbased calcium alkyl phenols, overbased calcium sulfur coupled alkyl phenol compounds, overbased calcium methylene bridged phenols, overbased magnesium phenates, overbased magnesium sulfur containing phenates, overbased magnesium sulfonates, overbased magnesium calixarates, overbased magnesium salixarates, overbased magnesium salicylates, overbased magnesium carboxylic acids, overbased magnesium phosphorus acids, overbased magnesium mono- and/or di-thiophosphoric acids, overbased magnesium alkyl phenols, overbased magnesium sulfur coupled alkyl phenol compounds, or overbased magnesium methylene bridged phenols.
The overbased calcium phenate detergents have a total base number of at least about 150 mg KOH/g, at least about 225 mg KOH/g, at least about 225 mg KOH/g to about 400 mg KOH/g, at least about 225 mg KOH/g to about 350 mg KOH/g or about 230 mg KOH/g to about 350 mg KOH/g, all as measured by the method of ASTM D2896. When such detergent compositions are formed in an inert diluent, e.g. a process oil, usually a mineral oil, the total base number reflects the basicity of the overall composition including diluent, and any other materials (e.g., promoter, etc.) that may be contained in the detergent composition.
The overbased detergent may have a metal to substrate ratio of from 1.1:1, or from 2:1, or from 4:1, or from 5:1, or from 7:1, or from 10:1. In some embodiments, a detergent is effective at reducing or preventing rust in an engine or other automotive part such as a transmission or gear. The detergent may be present in a lubricating composition at about 0 wt% to about 10 wt%, or about 0.1 wt% to about 8 wt%, or about 1 wt% to about 4 wt%, or greater than about 4 wt% to about 8 wt%.
Extreme Pressure Agents: The lubricating oil compositions herein also may optionally contain one or more extreme pressure agents. Extreme Pressure (EP) agents that are soluble in the oil include sulfur- and chlorosulfur-containing EP agents, chlorinated hydrocarbon EP agents and phosphorus EP agents. Examples of such EP agents include chlorinated wax; organic sulfides and polysulfides such as dibenzyldisulfide, bis(chlorobenzyl) disulfide, dibutyl tetrasulfide, sulfurized methyl ester of oleic acid, sulfurized alkyl phenol, sulfurized dipentene, sulfurized terpene, and sulfurized Diels-Alder adducts; phosphosulfurized hydrocarbons such as the reaction product of phosphorus sulfide with turpentine or methyl oleate; phosphorus esters such as the dihydrocarbyl and trihydrocarbyl phosphites, e.g., dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, pentylphenyl phosphite; dipentylphenyl phosphite, tridecyl phosphite, distearyl phosphite and polypropylene substituted phenyl phosphite; metal thiocarbamates such as zinc dioctyldithiocarbamate and barium heptylphenol diacid; amine salts of alkyl and dialkylphosphoric acids, including, for example, the amine salt of the reaction product of a dialkyldithiophosphoric acid with propylene oxide; and mixtures thereof.
Friction Modifiers: The lubricating oil compositions herein also may optionally contain one or more friction modifiers. Suitable friction modifiers may comprise metal containing and metal-free friction modifiers and may include, but are not limited to, imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, amino guanadine, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, sunflower oil other naturally occurring plant or animal oils, dicarboxylic acid esters, esters or partial esters of a polyol and one or more aliphatic or aromatic carboxylic acids, and the like.
Suitable friction modifiers may contain hydrocarbyl groups that are selected from straight chain, branched chain, or aromatic hydrocarbyl groups or mixtures thereof, and may be saturated or unsaturated. The hydrocarbyl groups may be composed of carbon and hydrogen or hetero atoms such as sulfur or oxygen. The hydrocarbyl groups may range from about 12 to about 25 carbon atoms. In some embodiments the friction modifier may be a long chain fatty acid ester. In another embodiment the long chain fatty acid ester may be a mono-ester, or a di-ester, or a (tri)glyceride. The friction modifier may be a long chain fatty amide, a long chain fatty ester, a long chain fatty epoxide derivatives, or a long chain imidazoline.
Other suitable friction modifiers may include organic, ashless (metal-free), nitrogen-free organic friction modifiers. Such friction modifiers may include esters formed by reacting carboxylic acids and anhydrides with alkanols and generally include a polar terminal group (e.g. carboxyl or hydroxyl) covalently bonded to an oleophilic hydrocarbon chain. An example of an organic ashless nitrogen-free friction modifier is known generally as glycerol monooleate (GMO) which may contain mono-, di-, and tri-esters of oleic acid. Other suitable friction modifiers are described in U.S. Pat. No. 6,723,685 , herein incorporated by reference in its entirety.
Aminic friction modifiers may include amines or polyamines. Such compounds can have hydrocarbyl groups that are linear, either saturated or unsaturated, or a mixture thereof and may contain from about 12 to about 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated ether amines. Such compounds may have hydrocarbyl groups that are linear, either saturated, unsaturated, or a mixture thereof. They may contain from about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated ether amines.
The amines and amides may be used as such or in the form of an adduct or reaction product with a boron compound such as a boric oxide, boron halide, metaborate, boric acid or a mono-, di- or tri-alkyl borate. Other suitable friction modifiers are described in U.S. Pat. No. 6,300,291 , herein incorporated by reference in its entirety.
A friction modifier may optionally be present in ranges such as about 0 wt% to about 10 wt%, or about 0.01 wt% to about 8 wt%, or about 0.1 wt% to about 4 wt%.
Transition Metal-containing compounds: In another embodiment, the oil-soluble compound may be a transition metal containing compound or a metalloid. The transition metals may include, but are not limited to, titanium, vanadium, copper, zinc, zirconium, molybdenum, tantalum, tungsten, and the like. Suitable metalloids include, but are not limited to, boron, silicon, antimony, tellurium, and the like.
In an embodiment, an oil-soluble transition metal-containing compound may function as antiwear agents, friction modifiers, antioxidants, deposit control additives, or more than one of these functions. In an embodiment the oil-soluble transition metal-containing compound may be an oil-soluble titanium compound, such as a titanium (IV) alkoxide. Among the titanium containing compounds that may be used in, or which may be used for preparation of the oils-soluble materials of, the disclosed technology are various Ti (IV) compounds such as titanium (IV) oxide; titanium (IV) sulfide; titanium (IV) nitrate; titanium (IV) alkoxides such as titanium methoxide, titanium ethoxide, titanium propoxide, titanium isopropoxide, titanium butoxide, titanium 2-ethylhexoxide; and other titanium compounds or complexes including but not limited to titanium phenates; titanium carboxylates such as titanium (IV) 2-ethyl-1-3-hexanedioate or titanium citrate or titanium oleate; and titanium (IV) (triethanolaminato)isopropoxide. Other forms of titanium encompassed within the disclosed technology include titanium phosphates such as titanium dithiophosphates (e.g., dialkyldithiophosphates) and titanium sulfonates (e.g., alkylbenzenesulfonates), or, generally, the reaction product of titanium compounds with various acid materials to form salts, such as oil-soluble salts. Titanium compounds can thus be derived from, among others, organic acids, alcohols, and glycols. Ti compounds may also exist in dimeric or oligomeric form, containing Ti--O--Ti structures. Such titanium materials are commercially available or can be readily prepared by appropriate synthesis techniques which will be apparent to the person skilled in the art. They may exist at room temperature as a solid or a liquid, depending on the particular compound. They may also be provided in a solution form in an appropriate inert solvent.
In one embodiment, the titanium can be supplied as a Ti-modified dispersant, such as a succinimide dispersant. Such materials may be prepared by forming a titanium mixed anhydride between a titanium alkoxide and a hydrocarbyl-substituted succinic anhydride, such as an alkenyl- (or alkyl) succinic anhydride. The resulting titanate-succinate intermediate may be used directly or it may be reacted with any of a number of materials, such as (a) a polyamine-based succinimide/amide dispersant having free, condensable --NH functionality; (b) the components of a polyamine-based succinimide/amide dispersant, i.e., an alkenyl- (or alkyl-) succinic anhydride and a polyamine, (c) a hydroxy-containing polyester dispersant prepared by the reaction of a substituted succinic anhydride with a polyol, aminoalcohol, polyamine, or mixtures thereof. Alternatively, the titanate-succinate intermediate may be reacted with other agents such as alcohols, aminoalcohols, ether alcohols, polyether alcohols or polyols, or fatty acids, and the product thereof either used directly to impart Ti to a lubricant, or else further reacted with the succinic dispersants as described above. As an example, 1 part (by mole) of tetraisopropyl titanate may be reacted with about 2 parts (by mole) of a polyisobutene-substituted succinic anhydride at 140-150° C for 5 to 6 hours to provide a titanium modified dispersant or intermediate. The resulting material (30 g) may be further reacted with a succinimide dispersant from polyisobutene-substituted succinic anhydride and a polyethylenepolyamine mixture (127 grams + diluent oil) at 150° C for 1.5 hours, to produce a titanium-modified succinimide dispersant.
Another titanium containing compound may be a reaction product of titanium alkoxide and C₆ to C₂₅ carboxylic acid. The reaction product may be represented by the following formula:
wherein n is an integer selected from 2, 3 and 4, and R is a hydrocarbyl group containing from about 5 to about 24 carbon atoms, or by the formula:
wherein m + n = 4 and n ranges from 1 to 3, R₄ is an alkyl moiety with carbon atoms ranging from 1-8, R₁ is selected from a hydrocarbyl group containing from about 6 to 25 carbon atoms, and R₂ and R₃ are the same or different and are selected from a hydrocarbyl group containing from about 1 to 6 carbon atoms, or the titanium compound may be represented by the formula:
wherein x ranges from 0 to 3, R₁ is selected from a hydrocarbyl group containing from about 6 to 25 carbon atoms, R₂, and R₃ are the same or different and are selected from a hydrocarbyl group containing from about 1 to 6 carbon atoms, and R₄ is selected from a group consisting of either H, or C₆ to C₂₅ carboxylic acid moiety.
Suitable carboxylic acids may include, but are not limited to caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, oleic acid, erucic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, phenylacetic acid, benzoic acid, neodecanoic acid, and the like.
In an embodiment the oil soluble titanium compound may be present in the lubricating oil composition in an amount to provide from 0 to 3000 ppm titanium by weight or 25 to about 1500 ppm titanium by weight or about 35 ppm to 500 ppm titanium by weight or about 50 ppm to about 300 ppm.
Viscosity Index Improvers: The lubricating oil compositions herein also may optionally contain one or more viscosity index improvers. Suitable viscosity index improvers may include polyolefins, olefin copolymers, ethylene/propylene copolymers, polyisobutenes, hydrogenated styrene-isoprene polymers, styrene/maleic ester copolymers, hydrogenated styrene/butadiene copolymers, hydrogenated isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkyl styrenes, hydrogenated alkenyl aryl conjugated diene copolymers, or mixtures thereof. Viscosity index improvers may include star polymers and suitable examples are described in US Publication No. 20120101017A1 .
The lubricating oil compositions herein also may optionally contain one or more dispersant viscosity index improvers in addition to a viscosity index improver or in lieu of a viscosity index improver. Suitable viscosity index improvers may include functionalized polyolefins, for example, ethylene-propylene copolymers that have been functionalized with the reaction product of an acylating agent (such as maleic anhydride) and an amine; polymethacrylates functionalized with an amine, or esterified maleic anhydride-styrene copolymers reacted with an amine.
The total amount of viscosity index improver and/or dispersant viscosity index improver may be about 0 wt% to about 20 wt%, about 0.1 wt% to about 15 wt%, about 0.1 wt% to about 12 wt%, or about 0.5 wt% to about 10 wt%, of the lubricating oil composition.
Other Optional Additives: Other additives may be selected to perform one or more functions required of a lubricating fluid. Further, one or more of the mentioned additives may be multi-functional and provide functions in addition to or other than the function prescribed herein.
A lubricating oil composition according to the present disclosure may optionally comprise other performance additives. The other performance additives may be in addition to specified additives of the present disclosure and/or may comprise one or more of metal deactivators, viscosity index improvers, detergents, ashless TBN boosters, friction modifiers, antiwear agents, corrosion inhibitors, rust inhibitors, dispersants, dispersant viscosity index improvers, extreme pressure agents, antioxidants, foam inhibitors, demulsifiers, emulsifiers, pour point depressants, seal swelling agents and mixtures thereof. Typically, fully-formulated lubricating oil will contain one or more of these performance additives.
Suitable metal deactivators may include derivatives of benzotriazoles (typically tolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazoles, benzimidazoles, 2-alkyldithiobenzimidazoles, or 2-alkyldithiobenzothiazoles; foam inhibitors including copolymers of ethyl acrylate and 2-ethylhexylacrylate and optionally vinyl acetate; demulsifiers including trialkyl phosphates, polyethylene glycols, polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene oxide) polymers; pour point depressants including esters of maleic anhydride-styrene, polymethacrylates, polyacrylates or polyacrylamides.
Suitable foam inhibitors include silicon-based compounds, such as siloxane.
Suitable pour point depressants may include polymethylmethacrylates or mixtures thereof. Pour point depressants may be present in an amount sufficient to provide from about 0 wt% to about 1 wt%, about 0.01 wt% to about 0.5 wt%, or about 0.02 wt% to about 0.04 wt% based upon the final weight of the lubricating oil composition.
Suitable rust inhibitors may be a single compound or a mixture of compounds having the property of inhibiting corrosion of ferrous metal surfaces. Non-limiting examples of rust inhibitors useful herein include oil-soluble high molecular weight organic acids, such as 2-ethylhexanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, behenic acid, and cerotic acid, as well as oil-soluble polycarboxylic acids including dimer and trimer acids, such as those produced from tall oil fatty acids, oleic acid, and linoleic acid. Other suitable corrosion inhibitors include long-chain alpha, omega-dicarboxylic acids in the molecular weight range of about 600 to about 3000 and alkenylsuccinic acids in which the alkenyl group contains about 10 or more carbon atoms such as, tetrapropenylsuccinic acid, tetradecenylsuccinic acid, and hexadecenylsuccinic acid. Another useful type of acidic corrosion inhibitors are the half esters of alkenyl succinic acids having about 8 to about 24 carbon atoms in the alkenyl group with alcohols such as the polyglycols. The corresponding half amides of such alkenyl succinic acids are also useful. A useful rust inhibitor is a high molecular weight organic acid.
The rust inhibitor, if present, can be used in an amount sufficient to provide about 0 wt% to about 5 wt%, about 0.01 wt% to about 3 wt%, about 0.1 wt% to about 2 wt%, based upon the final weight of the lubricating oil composition.

In general terms, a suitable lubricant including the detergent metals herein may include additive components in the ranges listed in the following table.

Table 2: Suitable Lubricating Compositions

	Component	Wt. % (Suitable Embodiments)	Wt. % (Preferred Embodiments)
Detergent Systems		1.0 - 5.0	1.0-3.0
Dispersant Systems		5.0 - 15.0	7.0 -10.0
Antioxidant(s)		1.0 - 5.0	2.0 - 3.0
Ashless TBN booster(s)		0.0 - 1.0	0.01 - 0.5
Corrosion inhibitor(s)		0.0 - 5.0	0.0 - 2.0
Metal dihydrocarbyldithiophosphate(s)		0.0 - 6.0	0.5- 2.0
Ash-free phosphorus compound(s)		0.0 - 60	0.0 - 40
Antifoaming agent(s)		0.0 - 1.0	0.001 - 0.15
Other Antiwear agent(s)		0.0 - 1.0	0.0 - 0.8
Pour point depressant(s)		0.0 - 1.0	0.00 - 0.5
Viscosity index improver(s)		0.0 - 150	1.0 - 100
Friction modifier(s)		0.00 - 1.0	0.01 - 0.8
Base oil		Balance	Balance
Total		100	100

The percentages of each component above represent the weight percent of each component, based upon the weight of the final lubricating oil composition. The remainder of the lubricating oil composition consists of one or more base oils. Additives used in formulating the compositions described herein may be blended into the base oil individually or in various sub-combinations. However, it may be suitable to blend all of the components concurrently using an additive concentrate (i.e., additives plus a diluent, such as a hydrocarbon solvent). Fully formulated lubricants conventionally contain an additive package, referred to herein as a dispersant/inhibitor package or DI package, that will supply the characteristics that are required in the formulation.

DEFINITIONS

For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75th Ed. Additionally, general principles of organic chemistry are described in "Organic Chemistry", Thomas Sorrell, University Science Books, Sausolito: 1999, and "March's Advanced Organic Chemistry", 5th Ed., Ed.: Smith, M.B. and March, J., John Wiley & Sons, New York: 2001, the entire contents of which are hereby incorporated by reference.
As described herein, compounds may optionally be substituted with one or more substituents, such as are illustrated generally above, or as exemplified by particular classes, subclasses, and species of the disclosure.
Unless otherwise apparent from the context, the term "major amount" is understood to mean an amount greater than or equal to 50 weight percent, for example, from about 80 to about 98 weight percent relative to the total weight of the composition. Moreover, as used herein, the term "minor amount" is understood to mean an amount less than 50 weight percent relative to the total weight of the composition.
As used herein, the term "hydrocarbyl group" or "hydrocarbyl" is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of a molecule and having a predominantly hydrocarbon character. Examples of hydrocarbyl groups include: (1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form an alicyclic radical); (2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of the description herein, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, amino, alkylamino, and sulfoxy); (3) hetero-substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this description, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Hetero-atoms include sulfur, oxygen, nitrogen, and encompass substituents such as pyridyl, furyl, thienyl, and imidazolyl. In general, no more than two, or as a further example, no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; in some embodiments, there will be no non-hydrocarbon substituent in the hydrocarbyl group.
As used herein the term "aliphatic" encompasses the terms alkyl, alkenyl, alkynyl, each of which being optionally substituted as set forth below.
As used herein, an "alkyl" group refers to a saturated aliphatic hydrocarbon group containing 1-12 (e.g., 1-8, 1-6, or 1-4) carbon atoms. An alkyl group can be straight or branched. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-heptyl, or 2-ethylhexyl. An alkyl group can be substituted (i.e., optionally substituted) with one or more substituents such as halo, phospho, cycloaliphatic [e.g., cycloalkyl or cycloalkenyl], heterocycloaliphatic [e.g., heterocycloalkyl or heterocycloalkenyl], aryl, heteroaryl, alkoxy, aroyl, heteroaroyl, acyl [e.g., (aliphatic)carbonyl, (cycloaliphatic)carbonyl, or (heterocycloaliphatic)carbonyl], nitro, cyano, amido [e.g., (cycloalkylalkyl)carbonylamino, arylcarbonylamino, aralkylcarbonylamino, (heterocycloalkyl) carbonylamino, (heterocycloalkylalkyl) carbonylamino, heteroarylcarbonylamino, heteroaralkyl carbonylamino alkylaminocarbonyl, cycloalkylaminocarbonyl, heterocycloalkylaminocarbonyl, arylaminocarbonyl, or heteroarylaminocarbonyl], amino [e.g., aliphaticamino, cycloaliphatic amino, or heterocycloaliphaticamino], sulfonyl [e.g., aliphatic-SO₂-], sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl, sulfamide, oxo, carboxy, carbamoyl, cycloaliphaticoxy, heterocyclo aliphaticoxy, aryloxy, heteroaryloxy, aralkyloxy, heteroarylalkoxy, alkoxycarbonyl, alkyl carbonyloxy, or hydroxy. Without limitation, some examples of substituted alkyls include carboxyalkyl (such as HOOC-alkyl, alkoxycarbonylalkyl, and alkylcarbonyloxyalkyl), cyanoalkyl, hydroxyalkyl, alkoxyalkyl, acylalkyl, aralkyl, (alkoxyaryl)alkyl, (sulfonylamino) alkyl (such as (alkyl-SO₂-amino)alkyl), aminoalkyl, amidoalkyl, (cycloaliphatic)alkyl, or haloalkyl.
As used herein, an "alkenyl" group refers to an aliphatic carbon group that contains 2-8 (e.g., 2-12, 2-6, or 2-4) carbon atoms and at least one double bond. Like an alkyl group, an alkenyl group can be straight or branched. Examples of an alkenyl group include, but are not limited to allyl, isoprenyl, 2-butenyl, and 2-hexenyl. An alkenyl group can be optionally substituted with one or more substituents such as halo, phospho, cycloaliphatic [e.g., cycloalkyl or cycloalkenyl], heterocycloaliphatic [e.g., heterocycloalkyl or hetero cycloalkenyl], aryl, heteroaryl, alkoxy, aroyl, heteroaroyl, acyl [e.g., (aliphatic) carbonyl, (cycloaliphatic)carbonyl, or (heterocycloaliphatic)carbonyl], nitro, cyano, amido [e.g., (cycloalkylalkyl)carbonylamino, arylcarbonylamino, aralkylcarbonylamino, (hetero cycloalkyl) carbonylamino, (heterocyclo alkylalkyl) carbonylamino, heteroarylcarbonylamino, heteroaralkylcarbonylamino alkylamino carbonyl, cycloalkylaminocarbonyl, hetero cyclo alkylaminocarbonyl, arylaminocarbonyl, or heteroarylaminocarbonyl], amino [e.g., aliphaticamino, cycloaliphaticamino, heterocyclo aliphaticamino, or aliphaticsulfonylamino], sulfonyl [e.g., alkyl-SO₂- , cycloaliphatic-SO₂-, or aryl-SO₂-], sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl, sulfamide, oxo, carboxy, carbamoyl, cycloaliphaticoxy, heterocycloaliphaticoxy, aryloxy, heteroaryloxy, aralkyloxy, heteroaralkoxy, alkoxycarbonyl, alkylcarbonyloxy, or hydroxy. Without limitation, some examples of substituted alkenyls include cyanoalkenyl, alkoxyalkenyl, acylalkenyl, hydroxyl alkenyl, aralkenyl, (alkoxyaryl) alkenyl, (sulfonylamino)alkenyl (such as (alkyl-SO₂-amino) alkenyl), aminoalkenyl, amidoalkenyl, (cycloaliphatic)alkenyl, or haloalkenyl.
As used herein, an "alkynyl" group refers to an aliphatic carbon group that contains 2-8 (e.g., 2-12, 2-6, or 2-4) carbon atoms and has at least one triple bond. An alkynyl group can be straight or branched. Examples of an alkynyl group include, but are not limited to, propargyl and butynyl. An alkynyl group can be optionally substituted with one or more substituents such as aroyl, heteroaroyl, alkoxy, cycloalkyloxy, heterocycloalkyloxy, aryloxy, heteroaryloxy, aralkyl oxy, nitro, carboxy, cyano, halo, hydroxy, sulfo, mercapto, sulfanyl [e.g., aliphaticsulfanyl or cycloaliphaticsulfanyl], sulfinyl [e.g., aliphaticsulfinyl or cycloaliphaticsulfinyl], sulfonyl [e.g., aliphatic-SO₂-, aliphaticamino-SO₂-, or cycloaliphatic-SO₂-], amido [e.g., aminocarbonyl, alkylaminocarbonyl, alkylcarbonylamino, cyclo alkylaminocarbonyl, heterocycloalkylaminocarbonyl, cycloalkylcarbonylamino, arylamino carbonyl, arylcarbonylamino, aralkylcarbonylamino, (heterocycloalkyl) carbonylamino, (cycloalkylalkyl) carbonylamino, heteroaralkylcarbonylamino, heteroaryl carbonylamino or heteroaryl amino carbonyl], urea, thiourea, sulfamoyl, sulfamide, alkoxycarbonyl, alkyl carbonyloxy, cyclo aliphatic, heterocycloaliphatic, aryl, heteroaryl, acyl [e.g., (cycloaliphatic) carbonyl or (hetero cyclo aliphatic)carbonyl], amino [e.g., aliphaticamino], sulfoxy, oxo, carboxy, carbamoyl, (cycloaliphatic)oxy, (heterocyclo aliphatic) oxy, or (heteroaryl)alkoxy.
As used herein, an "amino" group refers to -NR^XR^Y wherein each of R^X and R^Y is independently hydrogen, alkyl, cycloakyl, (cycloalkyl)alkyl, aryl, aralkyl, heterocycloalkyl, (heterocycloalkyl)alkyl, heteroaryl, carboxy, sulfanyl, sulfinyl, sulfonyl, (alkyl)carbonyl, (cycloalkyl)carbonyl, ((cycloalkyl)alkyl)carbonyl, arylcarbonyl, (aralkyl)carbonyl, (heterocyclo alkyl) carbonyl, ((heterocycloalkyl)alkyl)carbonyl, (heteroaryl)carbonyl, or (heteroaralkyl) carbonyl, each of which being defined herein and being optionally substituted. Examples of amino groups include alkylamino, dialkylamino, or arylamino. When the term "amino" is not the terminal group (e.g., alkylcarbonylamino), it is represented by -NR^X-. R^X has the same meaning as defined above.
As used herein, a "cycloalkyl" group refers to a saturated carbocyclic mono- or bicyclic (fused or bridged) ring of 3-10 (e.g., 5-10) carbon atoms. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, cubyl, octahydro-indenyl, decahydro-naphthyl, bicyclo[3.2.1]octyl, bicyclo[2.2.2] octyl, bicyclo[3.3.1]nonyl, bicyclo[3.3.2.]decyl, bicyclo[2.2.2]octyl, adamantyl, or ((aminocarbonyl)cycloalkyl)cycloalkyl.
As used herein, a "heterocycloalkyl" group refers to a 3-10 membered mono- or bicylic (fused or bridged) (e.g., 5- to 10-membered mono- or bicyclic) saturated ring structure, in which one or more of the ring atoms is a heteroatom (e.g., N, O, S, or combinations thereof). Examples of a heterocycloalkyl group include piperidyl, piperazyl, tetrahydropyranyl, tetrahydrofuryl, 1,4-dioxolanyl, 1,4-dithianyl, 1,3-dioxolanyl, oxazolidyl, isoxazolidyl, morpholinyl, thiomorpholyl, octahydrobenzofuryl, octahydrochromenyl, octahydrothio chromenyl, octahydroindolyl, octahydropyrindinyl, decahydroquinolinyl, octahydrobenzo[b] thiopheneyl, 2-oxa-bicyclo[2.2.2]octyl, 1-aza-bicyclo[2.2.2]octyl, 3-aza-bicyclo[3.2.1]octyl, and 2,6-dioxa-tricyclo[3.3.1.0]nonyl. A monocyclic heterocycloalkyl group can be fused with a phenyl moiety to form structures, such as tetrahydroisoquinoline, which would be categorized as heteroaryls.
A "heteroaryl" group, as used herein, refers to a monocyclic, bicyclic, or tricyclic ring system having 4 to 15 ring atoms wherein one or more of the ring atoms is a heteroatom (e.g., N, O, S, or combinations thereof) and in which the monocyclic ring system is aromatic or at least one of the rings in the bicyclic or tricyclic ring systems is aromatic. A heteroaryl group includes a benzofused ring system having 2 to 3 rings. For example, a benzofused group includes benzo fused with one or two 4 to 8 membered heterocycloaliphatic moieties (e.g., indolizyl, indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furyl, benzo[b]thiophenyl, quinolinyl, or isoquinolinyl). Some examples of heteroaryl are pyridyl, 1H-indazolyl, furyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, tetrazolyl, benzofuryl, isoquinolinyl, benzthiazolyl, xanthene, thioxanthene, phenothiazine, dihydroindole, benzo[1,3]dioxole, benzo[b]furyl, benzo[b] thiophenyl, indazolyl, benzimidazolyl, benzthiazolyl, puryl, cinnolyl, quinolyl, quinazolyl, cinnolyl, phthalazyl, quinazolyl, quinoxalyl, isoquinolyl, 4H-quinolizyl, benzo-1,2,5-thiadiazolyl, or 1,8-naphthyridyl.
Without limitation, monocyclic heteroaryls include furyl, thiophenyl, 2H-pyrrolyl, pyrrolyl, oxazolyl, thazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, 1,3,4-thiadiazolyl, 2H-pyranyl, 4-H-pranyl, pyridyl, pyridazyl, pyrimidyl, pyrazolyl, pyrazyl, or 1,3,5-triazyl. Monocyclic heteroaryls are numbered according to standard chemical nomenclature.
Without limitation, bicyclic heteroaryls include indolizyl, indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furyl, benzo[b]thiophenyl, quinolinyl, isoquinolinyl, indolizinyl, isoindolyl, indolyl, benzo[b]furyl, bexo[b]thiophenyl, indazolyl, benzimidazyl, benzthiazolyl, purinyl, 4H-quinolizyl, quinolyl, isoquinolyl, cinnolyl, phthalazyl, quinazolyl, quinoxalyl, 1,8-naphthyridyl, or pteridyl. Bicyclic heteroaryls are numbered according to standard chemical nomenclature.
As used herein, the term "treat rate" refers to the weight percent of a component in the lubricating compositions .
The weight average molecular weight (Mw) and the number average molecular weight (Mn) may be determined with a gel permeation chromatography (GPC) instrument obtained from Waters or the like instrument and the data processed with Waters Empower Software or the like software using commercially available polystyrene standards (with a Mn of 180 to about 18,000 as the calibration reference). See, for example, W. W. Yau, J. J. Kirkland and D. D. Bly, "Modern Size Exclusion Liquid Chromatography", John Wiley and Sons, New York, 1979, also incorporated herein by reference.

EXAMPLE

A better understanding of the present disclosure and its many advantages may be clarified with the following examples. The following examples are illustrative and not limiting thereof in either scope or spirit. Those skilled in the art will readily understand that variations of the components, methods, steps, and devices described in these examples can be used. Unless noted otherwise or apparent from the context of discussion in the Examples below and throughout this disclosure, all percentages, ratios, and parts noted in this disclosure are by weight.

Comparative and Inventive heavy duty crankcase lubricating oil compositions were evaluated for piston cleanliness on steel pistons pursuant to the OM471 Piston Cleanliness test of CEC L-118-21. The lubricating compositions evaluated for this Example included sulfonate and/or phenate detergents to provide the fluid relationships of Table 3 below. Other than the variations in Detergent System, Inventive 1 and Comparative 1 contained otherwise identical additive packages (with identical treat rates) and thus had identical Dispersant Systems, Antiwear Systems, Antioxidant Systems, antifoam agents, pour point depressants, viscosity modifiers, and had a balance of an API Group III base oil to achieve a target KV100 of between 11.4 to about 11.7 cSt, measured pursuant to ASTM D445. The Antioxidant System of Inventive 1 and Comparative 1 contained at least 1.0 weight percent of diphenylamine, at least 1.0 weight percent hindered phenol, and less than 0.2 weight percent molybdenum-containing compounds. In addition to the variations in the Detergent System, Comparative 2 also contained a reduced treat rate of dispersants in its Dispersant System, reduced treat rates of antioxidants in its Antioxidant System, and increased treat rate of zinc dithiophosphates in its Antiwear System. It is also noted that each fluid contained slight variations in process oil due to the differences in the amounts of additives provided. Soap content was calculated as explained in the textbook entitled "Chemistry and Technology of Lubricants", Third Edition, Edited by R. M. Mortier and S. T. Orszulik, Copyright 2010, pages 219 to 220 under the sub-heading 7.2.5. Detergent Classification.

Table 3: Heavy Duty Lubricating Oil Compositions

	Inventive 1	Comparative 1	Comparative 2
Detergent System
Sulfonate Soap delivered to the lubricating oil composition from Detergent B	0.47%	0.23%	0.60%
Sulfonate Soap delivered to the lubricating oil composition from Detergent C	0.21%	0%	0.09%
Phenate Soap delivered to the lubricating oil composition from Detergent A	0%	0.44%	0.39%
Total Sulfonate Soap	0.68%	0.23%	0.69%
Total Soap Content	0.68%	0.67%	1.08%
Calcium content (measured by ICP)	2355 ppm	2326 ppm	3860 ppm
TBN contribution from overbased sulfonate detergent*	5.6	2.7	7.1
Total TBN contribution from all sulfonate and phenate detergents*	5.7	6.1	10.1
Total TBN in lubricating oil composition (measured by ASTM D2896)	9.6	9.7	12

Dispersant System
Nitrogen delivered by dispersants (ppm, calculated)	1077 ppm	1077 ppm	740 ppm

Antioxidant System
Combination of alkylated diphenylamine, hindered phenol, and molybdenum containing antioxidants	2.7%	2.7%	1.15%

Antiwear System
Phosphorus delivered by ZDDP	780 ppm	780 ppm	970 ppm

* TBN of each sulfonate and phenate detergent was measured by ASTM D2896 and the TBN contribution from the sulfonates is calculated based on treat rate in the lubricating oil composition.

The detergent systems and dispersant systems of the heavy duty crankcase lubricants of Table 3 above included the following components:

Detergent A was an overbased calcium phenate with a TBN of about 250 and about 9.3 weight percent calcium.
Detergent B was an overbased calcium sulfonate with a TBN of about 307 and about 11.9 weight percent calcium.
Detergent C was a low-based calcium sulfonate with a TBN of about 28 and about 2.6 weight percent calcium.
Dispersant System contained a combination of polyisobutylene succinimide dispersants derived from highly reactive polyisobutylene, each having a number average molecular weight of between 1000 and 2500. Each dispersant had between 1.0 and 1.7 weight percent nitrogen.
Antioxidant System contained a mixture of alkylated diphenylamine, hindered phenolic antioxidants, and molybdenum containing compounds.
The Antiwear System comprised one or more zinc dithiophosphates delivering phosphorus to the fluid.

The heavy duty lubricants of Table 3 were evaluated for piston cleanliness pursuant to the OM471 Piston Cleanliness test (CEC L-118-21) using steel pistons. Results are provided in Table 4 below. Even though Comparative 1 was previously acceptable in the prior piston cleanliness test of OM501LA (CEC L-101-08) when using aluminum pistons, Comparative 1 did not achieve high piston cleanliness when tested using the new OM471 test on steel piston. It was unexpected that Inventive 1 containing only sulfonate soap achieved high piston cleanliness on steel pistons under the newer, more severe OM471 test. It is further expected that Inventive 1 would achieve high piston cleanliness in modified versions of the OM471 test using shorter test durations. Table 4: OM471 Steel Piston Cleanliness (CEC L-118-21)

Piston Cleanliness (grooves and under crown)

Inventive 1 94.7 %

Comparative 1 81.1 %*

Comparative 2 74.9 %*

*The fluids of Comparative Examples 1 and 2 were not able to complete the full test and scored the reported results after only 400 hours.
It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the," include plural referents unless expressly and unequivocally limited to one referent. Thus, for example, reference to "an antioxidant" includes two or more different antioxidants. As used herein, the term "include" and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items
For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
It is to be understood that each component, compound, substituent or parameter disclosed herein is to be interpreted as being disclosed for use alone or in combination with one or more of each and every other component, compound, substituent or parameter disclosed herein.
It is further understood that each range disclosed herein is to be interpreted as a disclosure of each specific value within the disclosed range that has the same number of significant digits. Thus, for example, a range from 1 to 4 is to be interpreted as an express disclosure of the values 1, 2, 3 and 4 as well as any range of such values.
It is further understood that each lower limit of each range disclosed herein is to be interpreted as disclosed in combination with each upper limit of each range and each specific value within each range disclosed herein for the same component, compounds, substituent or parameter. Thus, this disclosure to be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or with each specific value within each range, or by combining each upper limit of each range with each specific value within each range. That is, it is also further understood that any range between the endpoint values within the broad range is also discussed herein. Thus, a range from 1 to 4 also means a range from 1 to 3, 1 to 2, 2 to 4, 2 to 3, and so forth.
Furthermore, specific amounts/values of a component, compound, substituent or parameter disclosed in the description or an example is to be interpreted as a disclosure of either a lower or an upper limit of a range and thus can be combined with any other lower or upper limit of a range or specific amount/value for the same component, compound, substituent or parameter disclosed elsewhere in the application to form a range for that component, compound, substituent or parameter.
While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or can be presently unforeseen can arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they can be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.
The invention also relates to the following numbered embodiments:

1. A method of lubricating a heavy-duty diesel engine having steel pistons, the method comprising:
- lubricating the steel pistons of the heavy-duty diesel engine with a lubricating oil composition;
- wherein the lubricating oil composition includes (i) a detergent system consisting of one or more alkaline earth metal sulfonate detergents delivering from 0.3 to about 1 weight percent sulfonate soap to the lubricating oil composition and (ii) a dispersant system including one or more polyisobutylene succinimide dispersants delivering at least about 5 weight percent of the one or more dispersants to the lubricating oil composition; and
- wherein the one or more polyisobutylene succinimide dispersants are derived from highly reactive polyisobutylenes having a number average molecular weight of about 1,200 to about 2,500 and delivering more than 650 ppm nitrogen to the lubricating oil composition.
2. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 1, wherein the heavy-duty diesel engine is operated under conditions set forth in the OM471 Piston Cleanliness test of CEC L-118-21.
3. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 1, wherein the heavy-duty diesel engine is configured for powering a vehicle having a gross vehicle weight rating of about 6,000 pounds or higher.
4. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 1, wherein the detergent system consists of one or more overbased calcium sulfonate detergents and one or more low-based calcium sulfonate detergents, wherein an overbased detergent has a total base number (TBN) of at least about 300 mg KOH/g and a low-base detergent has a total base number (TBN) of about 175 mg KOH/g or less and with total base number (TBN) determined by ASTM D2896.
5. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 4, wherein the lubricating composition includes about 0.3 to about 0.7 weight percent of sulfonate soap.
6. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 4, wherein the detergent system includes an effective amount of the one or more overbased sulfonate detergents to provide at least about 5 mg KOH/g to the detergent system and an effective amounts of the one or more low-based sulfonate detergents to provide about 25 to about 40 weight percent of the detergent soap.
7. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 1, wherein the detergent system consists essentially of calcium sulfonate detergents.
8. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 1, wherein the detergent system is substantially free of magnesium sulfonate detergents, substantially free of phenate detergents, or combinations thereof.
9. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 1, wherein the lubricating oil composition includes about 50 ppm to about 200 ppm molybdenum provided by an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof.
10. The method of lubricating a heavy-duty diesel engine having steel pistons of claim 1, wherein the lubricating oil composition further includes about 0.5 to about 5 weight percent of one or more ashless antioxidants selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof.
11. The method of lubricating a heavy-duty diesel engine having steel pistons of embodiment 1, wherein the lubricating oil composition includes up to about 1200 ppm of phosphorus from one or more metal dihydrocarbyl dithiophosphate compounds having hydrocarbyl groups derived from a mixture of linear or branched primary alcohols and linear or branched secondary alcohols.
12. A heavy-duty crankcase lubricating oil composition suitable for a diesel engine having a gross vehicle weight of about 6,000 pounds or more, the heavy-duty crankcase lubricating oil composition comprising:
- one or more base oils of lubricating viscosity;
- a detergent system consisting of one or more alkaline earth metal sulfonate detergents delivering up to about 1 weight percent sulfonate soap to the lubricating oil composition;
- a dispersant system comprising one or more polyisobutylene succinimide dispersants delivering at least about 5 weight percent of the one or more dispersants to the lubricating composition; and
- wherein the one or more polyisobutylene succinimide dispersants are derived from highly reactive polyisobutylenes having a number average molecular weight of about 1,200 to about 2,500 and delivering more than 650 ppm nitrogen to the lubricating oil composition.
13. The heavy-duty crankcase lubricating oil composition of embodiment 12, wherein the lubricating oil composition achieves a steel piston cleanliness rating of at least about 90% as measured by the OM471 Piston Cleanliness Test (CEC L-118-21).
14. The heavy-duty crankcase lubricating oil composition of embodiment 12, wherein the detergent system consists of one or more overbased calcium sulfonate detergents and one or more low-based calcium sulfonate detergents, wherein an overbased detergent has a total base number (TBN) of at least about 200 mg KOH/g and a low-base detergent has a total base number (TBN) of about 175 mg KOH/g or less and with total base number (TBN) determined by ASTM D2896.
15. The heavy-duty crankcase lubricating oil composition of embodiment 13, wherein the detergent system includes an effective amount of the one or more overbased sulfonate detergents to provide at least about 5 mg KOH/g to the detergent system and an effective amounts of the one or more low-based sulfonate detergents to provide about 25 to about 40 weight percent of the detergent soap.
16. The heavy-duty crankcase lubricating oil composition of embodiment 12, wherein the detergent system consists essentially of calcium sulfonate detergents.
17. The heavy-duty crankcase lubricating oil composition of embodiment 12, wherein the detergent system is substantially free of magnesium sulfonate detergents, substantially free of phenate detergents, or combinations thereof.
18. The heavy-duty crankcase lubricating oil composition of embodiment 12, wherein the lubricating oil composition includes about 50 ppm to about 200 ppm molybdenum provided by an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof.
19. The heavy-duty crankcase lubricating oil composition of embodiment 12, wherein the lubricating oil composition further includes about 0.5 to about 5 weight percent of one or more ashless antioxidants selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof.
20. The heavy-duty crankcase lubricating oil composition of embodiment 1, wherein the lubricating oil composition includes up to about 1200 ppm of phosphorus from one or more metal dihydrocarbyl dithiophosphate compounds having hydrocarbyl groups derived from a mixture of linear or branched primary alcohols and linear or branched secondary alcohols.

Claims

A method of lubricating a diesel engine having steel pistons, the method comprising:
lubricating the steel pistons of the diesel engine with a lubricating oil composition;

wherein the lubricating oil composition includes (i) a detergent system consisting of one or more alkaline earth metal sulfonate detergents delivering from 0.3 to about 1 weight percent sulfonate soap to the lubricating oil composition and (ii) a dispersant system including one or more polyisobutylene succinimide dispersants delivering at least about 5 weight percent of the one or more dispersants to the lubricating oil composition; and

wherein the one or more polyisobutylene succinimide dispersants are derived from highly reactive polyisobutylenes having a number average molecular weight of about 1,200 to about 2,500 and delivering more than 650 ppm nitrogen to the lubricating oil composition.
The method of claim 1 wherein the diesel engine is a heavy-duty diesel engine and/or a heavy duty diesel engine having steel pistons.
The method of lubricating a heavy-duty diesel engine having steel pistons of claim 2, wherein the heavy-duty diesel engine is operated under conditions set forth in the OM471 Piston Cleanliness test of CEC L-118-21; and/or wherein the heavy-duty diesel engine is configured for powering a vehicle having a gross vehicle weight rating of about 6,000 pounds or higher.
The method of lubricating a diesel engine having steel pistons of any one of claims 1 to 3, wherein the detergent system consists of one or more overbased calcium sulfonate detergents and one or more low-based calcium sulfonate detergents, wherein an overbased detergent has a total base number (TBN) of at least about 200 mg KOH/g, preferably of at least about 300 mg KOH/g and a low-base detergent has a total base number (TBN) of about 175 mg KOH/g or less and with total base number (TBN) determined by ASTM D2896; in particular wherein the lubricating composition includes about 0.3 to about 0.7 weight percent of sulfonate soap; and/or wherein the detergent system includes an amount of the one or more overbased sulfonate detergents to provide at least about 5 mg KOH/g to the detergent system and an amount of the one or more low-based sulfonate detergents to provide about 25 to about 40 weight percent of the detergent soap.
The method of lubricating a diesel engine having steel pistons of any one of claims 1 to 4, wherein the detergent system is substantially free of magnesium sulfonate detergents, substantially free of phenate detergents, or combinations thereof,; in particular wherein the detergent system consists essentially of calcium sulfonate detergents.
The method of lubricating a diesel engine having steel pistons of any one of claims 1 to 5, wherein the lubricating oil composition includes about 50 ppm to about 200 ppm molybdenum provided by an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof.
The method of lubricating a diesel engine having steel pistons of any one of claims 1 to 6, wherein the lubricating oil composition further includes about 0.5 to about 5 weight percent of one or more ashless antioxidants selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof.
The method of lubricating a diesel engine having steel pistons of any one of claims 1 to 7, wherein the lubricating oil composition includes at least about 500 ppm of phosphorus and/or up to about 1200 ppm of phosphorus; preferably from about 600 ppm to about 1200 ppm phosphorus, more preferably from about 700 ppm to about 1,000 ppm phosphorus, or from about 700 ppm to about 1,200 ppm phosphorus from one or more metal dihydrocarbyl dithiophosphate compounds having hydrocarbyl groups derived from a mixture of linear or branched primary alcohols and linear or branched secondary alcohols.
A crankcase lubricating oil composition suitable for a diesel engine having a gross vehicle weight of about 6,000 pounds or more, the crankcase lubricating oil composition comprising:
one or more base oils of lubricating viscosity;

a detergent system consisting of one or more alkaline earth metal sulfonate detergents delivering up to about 1 weight percent sulfonate soap to the lubricating oil composition;

a dispersant system comprising one or more polyisobutylene succinimide dispersants delivering at least about 5 weight percent of the one or more dispersants to the lubricating composition; and

wherein the one or more polyisobutylene succinimide dispersants are derived from highly reactive polyisobutylenes having a number average molecular weight of about 1,200 to about 2,500 and delivering more than 650 ppm nitrogen to the lubricating oil composition.
The crankcase lubricating composition of claim 9, being a heavy-duty crankcase lubricating composition.
The crankcase lubricating oil composition of claim 10, wherein the lubricating oil composition achieves a steel piston cleanliness rating of at least about 90% as measured by the OM471 Piston Cleanliness Test (CEC L-118-21).
The crankcase lubricating oil composition of any one of claims 9 to 11, wherein the detergent system consists of one or more overbased calcium sulfonate detergents and one or more low-based calcium sulfonate detergents, wherein an overbased detergent has a total base number (TBN) of at least about 200 mg KOH/g, preferably at least about 300 mg KOH/g and a low-base detergent has a total base number (TBN) of about 175 mg KOH/g or less and with total base number (TBN) determined by ASTM D2896; in particular wherein the lubricating composition includes about 0.3 to about 0.7 weight percent of sulfonate soap; and/orwherein the detergent system includes an effective amount of the one or more overbased sulfonate detergents to provide at least about 5 mg KOH/g to the detergent system and an effective amounts of the one or more low-based sulfonate detergents to provide about 25 to about 40 weight percent of the detergent soap.
The crankcase lubricating oil composition of any one of claims 9 to 12, wherein the detergent system is substantially free of magnesium sulfonate detergents, substantially free of phenate detergents, or combinations thereof; in particular wherein the detergent system consists essentially of calcium sulfonate detergents.
The crankcase lubricating oil composition of any one of claims 9 to 13, wherein the lubricating oil composition includes about 50 ppm to about 200 ppm molybdenum provided by an oil-soluble molybdenum compound selected from the group of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, sulfur-free organomolybdenum complexes of organic amides, or mixtures thereof.
The crankcase lubricating oil composition of any one of claims 9 to 14, wherein the lubricating oil composition further includes about 0.5 to about 5 weight percent of one or more ashless antioxidants selected from hindered phenols, aromatic amines, alkylated diphenylamines, phenyl-α-napthylamines, alkylated phenyl-α-naphthylamines, hindered non-aromatic amines sulfurized olefins, or mixtures thereof.
The crankcase lubricating oil composition of any one of claims 1 to 15, wherein the lubricating oil composition includes up to about 1200 ppm of phosphorus from one or more metal dihydrocarbyl dithiophosphate compounds having hydrocarbyl groups derived from a mixture of linear or branched primary alcohols and linear or branched secondary alcohols.