KR20220062013A - Reduce friction in combustion engines through fuel additives - Google Patents

Abstract

A fuel composition for improving fuel efficiency is provided. The fuel composition comprises greater than 50% by weight of a hydrocarbon fuel boiling in the gasoline or diesel range, traces of zinc chelating agents and traces of friction modifiers. The friction modifier includes at least one polar group.

Description

Reduce friction in combustion engines through fuel additives

The present disclosure relates to fuel additive compositions. More specifically, the present disclosure relates to friction modifier additives that may be added to fuels to improve fuel economy of internal combustion engines.

Significant efforts have been made in recent years to improve the fuel economy of motor vehicles. In general, the efficiency of automobile engines is greatly improved by the presence of effective lubrication, especially at the interfaces of moving parts, which are prone to high friction and excessive wear.

Accordingly, one approach to improving fuel economy has been to develop lubricants and lubricant additives that reduce engine friction, thereby reducing energy requirements. However, the fuel economy improvements obtained with lubricant friction reducing additives have been minimal and may be difficult to ascertain.

Some of these efforts have focused on friction modifiers. Friction modifiers have been used in limited slip gear oils, automatic transmission fluids, runway lubricants and general purpose tractor fluids. Friction modifiers have been added to automotive crankcase lubricants, particularly in the desire to improve fuel economy.

These friction modifiers are generally used to form thin mono-molecular layers of physically adsorbed polar oil-soluble products or reactive layers that exhibit significantly lower friction compared to typical anti-wear or extreme pressure formulations. It operates in boundary layer conditions at temperatures that are not yet reactive by However, under more severe conditions and in mixed lubrication regimes, these friction modifiers are added along with anti-wear or extreme pressure agents. The most common type of anti-wear or extreme pressure agent is zinc dithiophosphate (ZnDTP or ZDDP). ZDDP limits wear by forming a thick protective friction film on the friction surface.

Although ZDDP has been widely used in motor vehicles for decades, some recent studies have shown that phosphorus-based wear-resistant films can cause significant increases in friction in thin-film, high-pressure, lubricated contacts. This in turn can negatively affect fuel economy.

Friction modifiers are known lubricant additives capable of reducing boundary friction by adsorbing or reacting to metal surfaces to form thin low-shear-strength films.

Because the conditions in the internal combustion chamber are substantially different from, and much harsher than, those in the crankcase, the fact that a particular additive or class of additives has an advantage in the performance of lubricating oils in an internal combustion engine is a compound of the same type as the additives in the fuel. It does not necessarily mean that you can benefit from using . Accordingly, there is a need to develop fuel additives capable of reducing friction and/or improving fuel economy.

Provided herein are compositions that can be added to fuels as additives to provide improved fuel economy and/or reduced friction in internal combustion engines. These fuel additives include friction modifiers and metal chelators that interact synergistically to provide unexpected levels of performance.

One embodiment of the present invention comprises greater than 50% by weight hydrocarbon fuel boiling in the gasoline or diesel range; trace amounts of zinc chelating agents; and a fuel composition comprising a trace amount of a friction modifier, wherein the friction modifier comprises at least one polar group.

Another embodiment of the present invention is a fuel economy improver comprising (1) 90 to 30% by weight of an organic solvent boiling in the range of 65°C to 205°C, and (2) a zinc chelating agent and a friction modifier having at least one polar group. and a fuel thickening composition comprising 70% by weight.

Another embodiment of the present invention includes a method for improving fuel economy in a spark-ignited combustion engine, the method comprising supplying to the engine a fuel composition comprising a friction modifier having at least one polar group and a zinc chelating agent do.

1 shows a graph summarizing the effect of different fuel additives on fuel consumption at various engine conditions.

To facilitate understanding of the disclosure presented herein, a number of terms are defined below. Unless defined otherwise, all technical and scientific terms used herein generally have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

“Gasoline” or “gasoline boiling range component” refers to a composition containing at least predominantly C ₄ -C ₁₂ hydrocarbons. In one embodiment, gasoline or gasoline boiling range component is intended to refer to a composition containing at least predominantly C ₄ -C ₁₂ hydrocarbons and further having a boiling range of from about 100°F (37.8°C) to about 400°F (204°C). further defined. In an alternative embodiment, the gasoline or gasoline boiling range component contains at least predominantly C ₄ -C ₁₂ hydrocarbons, has a boiling range of from about 100°F (37.8°C) to about 400°F (204°C), and meets ASTM D4814 is defined to refer to a composition further defined to

The term “diesel” refers to distillate fuels containing at least predominantly C ₁₀ -C ₂₅ hydrocarbons. In one embodiment, diesel is further defined to refer to a composition containing at least predominantly C ₁₀ -C ₂₅ hydrocarbons and further having a boiling range of from about 165.6° C. (330° F.) to about 371.1° C. (700° F.) . In an alternative embodiment, the diesel contains at least predominantly C ₁₀ -C ₂₅ hydrocarbons, has a boiling range of from about 165.6° C. (330° F.) to about 371.1° C. (700° F.), further defined to meet ASTM D975. As defined above to refer to a composition.

The term "oil soluble" means that for a given additive the amount necessary to provide the desired level of activity or performance can be incorporated by dissolving, dispersing or suspending in an oil of lubricating viscosity. Typically, this means that at least 0.001% by weight of the additive may be incorporated into the lubricating oil composition. The term “fuel soluble” is a similar expression for additives dissolved, dispersed or suspended in a fuel.

By “minor amount” is meant less than 50% by weight of the composition, expressed relative to the total weight of the stated additive and composition, calculated as the active ingredient of the additive.

An “engine” or “combustion engine” is a heat engine in which combustion of fuel takes place in a combustion chamber. An “internal combustion engine” is a heat engine in which the combustion of fuel takes place in a confined space (“combustion chamber”). A “spark ignition engine” is a heat engine in which combustion is ignited by a spark, typically from a spark plug. This is in contrast to a "compression-ignition engine", typically a diesel engine, in which the heat resulting from compression with the injection of fuel is sufficient to start combustion without an external spark.

"Zinc chelator" refers to any substance capable of chelating zinc (Zinc ²⁺ ) ions.

The present disclosure describes additive compositions that can be added to fuels to improve friction reduction and/or to improve fuel economy of internal combustion engines. The additive composition (“fuel economy improver”) comprises at least two components: a friction modifier and a zinc chelating agent. When formulated in accordance with the present disclosure, these ingredients take advantage of previously unknown synergistic effects to provide greater than expected improvements in friction reduction and/or fuel economy in engines.

It is believed that additives added to the fuel can be delivered as lubricants to the engine piston ring section which can improve economy by reducing friction and wear. However, additives added to the lubricant may not necessarily be transferred to the fuel. Thus, friction modifiers can provide fuel economy by reducing friction in the combustion chamber of an internal combustion engine.

zinc chelating agent

The chelating agent used in the present fuel composition includes an organic molecule capable of chelating zinc. In general, these chelating agents can form internal complexes with zinc through chelate ring formation. The zinc chelating agent may depend on its denticity, ie the number of atoms of the chelating agent that binds zinc. For example, the zinc chelating agent may be a bidentate.

Without wishing to be bound by theory, it is believed that the zinc chelating agents of the present invention may limit the friction caused or induced by ZDDP in the engine environment. The limiting effect can be synergistically enhanced when the friction modifier of the present invention is also present. Although the mechanism is not fully understood, it is believed that the friction modifiers of the present invention can form a friction-reducing film on zinc phosphate surfaces and/or stabilize zinc chelators in engine environments.

In some embodiments, the zinc chelating agent may be fuel soluble. In other embodiments, the zinc chelating agent may not be oil soluble. In the absence of the friction modifier of the present invention, the lack of oil solubility can prevent the zinc chelating agent from chelating with the zinc species in the lubricant environment.

Zinc chelating agents of the present invention include dicarbonyl compounds, bidentate nitrogen compounds, polydentate nitrogen compounds, amino acids, citrate esters, carboxylate salts, amine salts, or suitable salts thereof. The metal chelating agent is present at about 25 to about 5000 ppm of the fuel composition.

The dicarbonyl compound may have the structure shown in Formula 1, wherein R ₁ and R ₂ are independently an aliphatic, aliphatic branched, cyclic aliphatic, aromatic, substituted aromatic, or unsaturated (eg, olefinic) moiety. It is moiety.

Equation 1

A specific example of a dicarbonyl chelating agent is acetyl acetone. When acetyl acetone acts as a bidentate ligand it is often referred to as "acac".

Other dicarbonyl compounds include chelating agents having the structure shown in Formula 2, wherein X is O or N and has the correct valence, and R ₁ , R ₂ and R ₃ are independently aliphatic, aliphatic branched, cyclic aliphatic , an aromatic, substituted aromatic or unsaturated (eg, olefinic) moiety. Additionally, R ₂ and R ₃ may also be H (sufficient to satisfy the valence of X). Specific examples include ethyl acetoacetate, acetoacetic acid ester and acetoacetic acid amide.

Equation 2

Some bidentate nitrogen compounds will generally have at least one nitrogen atom capable of coordinating directly to zinc or at least stabilizing coordination to zinc to a nearby atom. For example, the bidentate nitrogen compound may have a structure shown in Formula 3 below, wherein R ₁ and R ₂ are independently aliphatic, aliphatic branched, cyclic aliphatic, aromatic, substituted aromatic, unsaturated (eg, olefinic) moiety or H. Both nitrogen and oxygen can coordinate with zinc to form a chelate ring.

Equation 3

Other bidentate nitrogen compounds are also contemplated. Specific examples of bidentate nitrogen compounds include hydroxamic acid (Formula 4), hydrazide (Formula 5), squaric acid (Formula 6), carbamoylphosphonate (Formula 7), oxazoline (Formula 8) and N -hydroxyurea (Formula 9), wherein R is independently an aliphatic, aliphatic branched, cyclic aliphatic, aromatic, substituted aromatic, unsaturated (eg, olefinic) moiety or H.

Other specific examples of bidentate nitrogen chelating agents are amino methyl compounds, methyl pyridyl compounds, quinolyl compounds, pyrazyl compounds, 5-membered N-heterocyclic compounds (eg, pyrrole/pyrroly din, imidazole/imidazoline, triazole) and diethanolisostearamide.

Multidentate nitrogen compounds may also be suitable for the present invention. Specific examples of these include N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (formula 10) and ethylenediaminetetraacetic acid (formula 11).

Equation 10

Equation 11

amino acid

Amino acids include those which can be represented by the general formula:

Equation 12

wherein R is an “aliphatic” or “aromatic” side chain. Amino acid side chains can be broadly classified as aromatic or aliphatic. Aromatic side chains include aromatic rings. Examples of amino acids having aromatic side chains include, for example, histidine ( formula 13 ), phenylalanine ( formula 14 ), tyrosine ( formula 15 ), tryptophan ( formula 16 ), and the like. Non-aromatic side chains are broadly classified as "aliphatic" and include, for example, alanine ( Formula 17 ), glycine ( Formula 18 ), cysteine ( Formula 19 ), and the like.

The amino acid(s) may be natural and/or non-natural α-amino acids. Natural amino acids are amino acids encoded by the genetic code as well as amino acids derived therefrom. These include, for example, hydroxyproline ( Formula 20 ), γ-carboxyglutamate ( Formula 21 ) and citrulline ( Formula 22 ). As used herein, the term “amino acid” also includes amino acid analogs and mimetics. Analogs are compounds that have the same general structure of a natural amino acid, except that the R group is not found in the natural amino acid.

Representative examples of naturally occurring amino acid analogs include homoserine ( Formula 23 ), norleucine ( Formula 24 ), homoproline ( Formula 25 ) and proline ( Formula 26 ). Amino acid mimetics are compounds that have a structure different from the general chemical structure of α-amino acids, but function in a similar manner. The amino acid may be an L- or D-amino acid. A representative structure is shown below.

Other zinc chelating agents

Zinc chelating agents can be prepared from carboxylate esters with various non-polar groups. Zinc chelating agents may also include multi-functional esters, including citrate esters. The citrate ester can have the structure shown in formula 27 wherein R is an alkyl, alkenyl, cycloalkyl, aromatic or substituted aromatic moiety.

Specific examples of carboxylate salts include the 1,1,3,3-tetramethylguanidine salt of 2-ethylhexanoic acid (TMG/2-EH), wherein TMG/2-EH is represented by Formula 28.

friction modifier

Friction modifiers are additives capable of reducing friction and/or wear in machine components. The friction modifiers of the present invention include organic friction modifiers having at least one polar group. These friction modifiers are typically bifunctional in that the friction modifier will also generally have long chain and/or aromatic non-polar groups.

The polar group may be an alcohol moiety, an amide moiety, an amine moiety, an ester moiety, or the like. In some embodiments, the friction modifier may have more than one polar moiety (eg, a diol, diester, alkanol amide, etc.).

The friction modifier may be fuel soluble and/or oil soluble. The friction modifier of the present invention stabilizes the zinc chelating agent in a lubricating environment so that the zinc chelating agent chelates zinc and also adsorbs on the zinc phosphate friction film to form a friction reducing layer.

Specific friction modifiers having an ester moiety include esters of carboxylic acids, adipate esters, trimethylolpropane triesters, polyol esters (eg, glycerol esters, sorbitan esters, etc.), polyesters, and high viscosity index (VI) ) and/or alter hydrodynamic friction. In some embodiments, the ester may be borated.

Other suitable friction modifiers include alkanol amides (including polar group-capped fatty amides and polyol amines). Particular alkanol amides include diethanolamide.

Amine friction modifiers include hydrocarbyl amines, fatty acid amines (eg, oleylamine), and ethoxylated alkyl amines. Particular amine friction modifiers include diethanolamine and diisopropanolamine.

Specific friction modifiers are described in more detail, for example, in US7678747, US8703680, and US9371499, which are incorporated herein by reference.

In particular, polyol esters are often used as synthetic basestock oils that can be synthesized from polyols and acids (eg, branched acids, linear saturated acids, polybasic acids). Examples of polyol esters include glycerol esters, sorbitan esters, and the like.

Specific glycerol esters include glycerol monooleate (or glyceryl monooleate), which is a friction modifier that is typically added to lubricant compositions. For example, US Pat. Nos. 5,114,603 and 4,683,069 describe lubricating oil compositions comprising glycerol monooleate, the relevant portions of which are incorporated herein by reference.

Examples of commercially available glycerol monooleate include Priolube™ 1408 and Radiasurf™ 7149 (ie, esters of fatty acids including glycerol trioleate). In a typical commercial product, only about 50-60 mole percent of the esters produced are monoesters. The remainder are mainly diesters, with small amounts of triesters.

Typically, the fuel composition of the present invention contains at least 0.015% by weight, preferably 0.15 to 2.0% by weight of a friction modifier.

The glycerol esters useful in the present invention are fuel-soluble and are preferably prepared from C12 to C22 fatty acids or mixtures thereof as found in natural products. Fatty acids may be saturated or unsaturated. Certain compounds found in acids of natural sources may include licanoic acid containing one keto group. Most preferred C16 to C18 fatty acids are those of the formula R-COOH, wherein R is alkyl or alkenyl. Preferred fatty acids are oleic acid, stearic acid, isostearic acid, palmitic acid, myristic acid, palmitoleic acid, linoleic acid, lauric acid, linolenic acid and eleostearic acid, acids from natural products are tallow, palm oil, olive oil, peanut milk, corn oil, nit foot oil and the like. A particularly preferred acid is oleic acid.

Fatty acid monoesters of glycerol are preferred, although mixtures of mono- and diesters may be used. Preferably any mixture of mono- and diesters contains at least 40% monoester. Typically these mixtures of mono- and diesters of glycerol contain from 40 to 60 weight percent of the monoester. For example, commercially available glycerol monooleate contains a mixture of 45% to 55% monoester and 55% to 45% diester by weight. However, higher monoesters may be achieved by distilling a mixture of glycerol monoesters, diesters, triesters using conventional distillation techniques with the monoester portion of the recovered distillation product. This can result in products that are essentially all monoesters. Accordingly, the esters used in the fuel compositions of the present invention may all be monoesters, or may be mixtures of mono- and diesters wherein at least 75 mole percent, preferably at least 90 mole percent, of the mixture are monoesters.

fuel composition

The compounds of the present disclosure may be useful as additives in hydrocarbon fuels to prevent or reduce engine knock or pre-ignition events in spark-ignited internal combustion engines.

The compounds of the present disclosure may be formulated as concentrates using inert stable oleophilic (ie, soluble in hydrocarbon fuels) organic solvents boiling in the range of 65°C to 205°C. Aliphatic or aromatic hydrocarbon solvents such as benzene, toluene, xylene or high boiling aromatic or aromatic diluents may be used. In combination with hydrocarbon solvents, aliphatic alcohols containing 2 to 8 carbon atoms, such as ethanol, isopropanol, methyl isobutyl carbinol, n -butanol, and the like, are also suitable for use with the present additive. The amount of additive in the concentrate may range from 10 to 70 weight percent (eg, 20 to 40 weight percent).

In gasoline fuels, oxygenates (eg, ethanol, methyl tert -butyl ether), other anti-knocking agents, and detergents/dispersants (eg, hydrocarbyl amines, hydrocarbyl poly(oxyalkylene) amines) , succinimides, Mannich reaction products, aromatic esters of polyalkylphenoxyalkanols, or polyalkylphenoxyaminoalkanes) may be used. Additionally, friction modifiers, antioxidants, metal deactivators and demusifiers may be present.

In diesel fuel, other well-known additives may be used, such as pour point depressants, flow improvers, cetane improvers, and the like.

Fuel-soluble, non-volatile carrier fluids or oils may also be used with the compounds of the present disclosure. The carrier fluid is a chemically inert hydrocarbon-soluble liquid vehicle that substantially increases the non-volatile residue (NVR) or solvent-free liquid fraction of the fuel additive composition without overwhelmingly contributing to an increase in octane demand. Carrier fluids include natural or synthetic oils, such as mineral oil, refined petroleum oil, synthetic polyalkanes and alkenes, including hydrogenated and non-hydrogenated polyalphaolefins, synthetic polyoxyalkylene-derived oils, such as U.S. Patent Nos. 3,756,793; 4,191,537; and 5,004,478; and European Patent Application Publication Nos. 356,726 and 382,159.

The carrier fluid may be used in an amount ranging from 35 to 5000 ppm by weight of the hydrocarbon fuel (eg, 50 to 3000 ppm of the fuel). When used in fuel concentrates, the carrier fluid may be present in an amount ranging from 20 to 60 weight percent (eg, 30 to 50 weight percent).

The following non-limiting examples are provided to illustrate one or more aspects of the present invention.

Example 1

fuel consumption test

Additives were added to the fuel to make fuel composition samples. Samples are summarized in Table 1 below. Table 2 summarizes the various conditions of the fuel consumption test.

[Table 1]

[Table 2]

1 shows the results of fuel consumption tests on fuel samples under various engine conditions. The engine rpm range is from 1100 to 3000 rpm while the pressure range is from 2 to 14 bar.

Claims (20)

greater than 50% by weight of hydrocarbon fuels boiling in the gasoline or diesel range;
trace amounts of zinc chelating agents; and
Trace amount of friction modifier comprising at least one polar group
A fuel composition comprising a. The fuel composition of claim 1 , wherein at least one polar group is an alcohol moiety, an amide moiety, an amine moiety or an ester moiety. The fuel composition of claim 1 , wherein the metal chelating agent is present at 25 to 5000 ppm. The fuel composition of claim 1 , wherein the friction modifier is present at 0.015 to 2.0% by weight. 2. The method of claim 1 wherein the zinc chelating agent is a dicarbonyl moiety, an ester moiety, an amide moiety, an amine moiety, an amino methyl moiety, a methyl pyridyl moiety, a quinolyl moiety, a pyrazyl moiety , a nitrogen heterocycle moiety, a pyrrole moiety, a pyrrolidine moiety, an imidazole moiety, an imidazoline moiety, a triazole moiety, or a carboxylate moiety. 2. The method of claim 1, wherein the zinc chelating agent is acetyl acetone, ethyl acetoacetate, acetoacetic acid ester, acetoacetic acid amide, hydroxamic acid, hydrazide, squaric acid, carbamoylphosphonate, oxazoline, N-hydroxyurea , N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine, ethylenediaminetetraacetic acid, histidine, phenylalanine, tyrosine, tryptophan, alanine, glycine, cysteine, hydroxyproline , γ-carboxyglutamate, citrulline, homoserine, norleucine, homoproline, proline, or 1,1,3,3-tetramethylguanidine salt of 2-ethylhexanoic acid, or diethanolisostearamide. The fuel composition of claim 1 , wherein the friction modifier is glycerol monooleate, diethanolamide, diethanolamine or diisopropanolamine. The fuel composition of claim 1 , further comprising oxygenates, anti-knocking agents, detergents, dispersants, antioxidants, metal deactivators, demulsifiers, pour point depressants, flow improvers, or cetane improvers. (1) 90 to 30% by weight of an organic solvent boiling in the range of 65°C to 205°C and (2) 10 to 70% by weight of a fuel economy improver comprising a zinc chelating agent and a friction modifier having at least one polar group A fuel enrichment composition comprising a. 10. The fuel enrichment composition of claim 9, wherein the at least one polar group is an alcohol moiety, an amide moiety, an amine moiety or an ester moiety. 10. The method of claim 9, wherein the zinc chelating agent is a dicarbonyl moiety, an ester moiety, an amide moiety, an amine moiety, an amino methyl moiety, a methyl pyridyl moiety, a quinolyl moiety, a pyrazyl moiety, a nitrogen hetero A fuel enrichment composition comprising a cycle moiety, a pyrrole moiety, a pyrrolidine moiety, an imidazole moiety, an imidazoline moiety, a triazole moiety, or a carboxylate moiety. 10. The fuel concentrate composition of claim 9, further comprising an oxygenating agent, an anti-knocking agent, a detergent, a dispersing agent, an antioxidant, a metal deactivator, a demulsifier, a pour point depressant, a flow improver, or a cetane improver. A method for improving fuel economy in a spark-ignited combustion engine, comprising:
A method comprising supplying an engine with a fuel composition comprising a zinc chelating agent and a friction modifier having at least one polar group. 14. The method of claim 13, wherein the at least one polar group is an alcohol moiety, an amide moiety, an amine moiety or an ester moiety. 14. The method of claim 13, wherein the zinc chelating agent is a dicarbonyl moiety, an ester moiety, an amide moiety, an amine moiety, an amino methyl moiety, a methyl pyridyl moiety, a quinolyl moiety, a pyrazyl moiety, a nitrogen hetero containing a cycle moiety, a pyrrole moiety, a pyrrolidine moiety, an imidazole moiety, an imidazoline moiety, a triazole moiety, or a carboxylate moiety. 14. The method of claim 13, wherein the zinc chelating agent is acetyl acetone, ethyl acetoacetate, acetoacetic acid ester, acetoacetic acid amide, hydroxamic acid, hydrazide, squaric acid, carbamoylphosphonate, oxazoline, N-hydroxyurea , N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine, ethylenediaminetetraacetic acid, histidine, phenylalanine, tyrosine, tryptophan, alanine, glycine, cysteine, hydroxyproline , γ-carboxyglutamate, citrulline, homoserine, norleucine, homoproline, proline, or 1,1,3,3-tetramethylguanidine salt of 2-ethylhexanoic acid, or diethanolisostearamide. 14. The method of claim 13, wherein the friction modifier is present at 0.015 to 2.0 weight percent. 14. The method of claim 13, wherein the zinc chelating agent is present at 25 to 5000 ppm of the fuel composition. 14. The method of claim 13, wherein the fuel composition further comprises an oxygenating agent, an anti-knocking agent, a detergent, a dispersant, an antioxidant, a metal deactivator, a demulsifier, a pour point depressant, a flow improver, or a cetane improver. 14. The method of claim 13, wherein the engine operates at 1000 to 3000 rpm.

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