US20050268532A1

US20050268532A1 - Motor fuel additive composition

Info

Publication number: US20050268532A1
Application number: US10/709,862
Authority: US
Inventors: Otis Nelson; Mark Nelson; A. Nelson; Chandra Prakash; Gilbert Chapelet
Original assignee: Polar Molecular Corp
Current assignee: Polar Molecular Corp
Priority date: 2004-06-02
Filing date: 2004-06-02
Publication date: 2005-12-08
Also published as: WO2005121282A2; WO2005121282A3

Abstract

Disclosed is a MMT containing motor fuel additive composition which synergistically combines the octane enhancing capabilities of MMT with the benefits of a special additive package to reduce both fuel intake system deposit formation and combustion chamber deposit formation, thereby reducing engine ORI and maintaining desired engine performance.

Description

BACKGROUND OF INVENTION

1. Field of the Invention
This invention relates to a MMT motor fuel additive composition for bulk fuel addition. More particularly, this invention relates to a motor fuel additive composition comprising: (a) a fuel conditioner component comprising (i) a polar oxygenated hydrocarbon compound, and (ii) an oxygenated compatibilizing agent; and (b) methylcyclopentadienyl manganese tricarbonyl (MMT) for use in bulk production of motor fuels providing improved performance and decreased ORI.
Furthermore, this invention relates to a motor fuel additive composition comprising: (a) a detergent component selected from the group consisting of (i) a reaction product component which is the reaction product of a substituted hydrocarbon and an amino compound, and (ii) a succinic anhydride or succinic dibasic acid and (iii) a polybutylamine or polyisobutylamine; and (b) a fuel conditioner component comprising (i) a polar oxygenated hydrocarbon compound, and (ii) an oxygenated compatibilizing agent, and (c) methylcyclopentadienyl manganese tricarbonyl (MMT) for use in bulk production of motor fuels providing improved performance and decreased ORI.
2. Description of the Related Art
Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic manganese compound designed to enhance octane levels in gasoline. The additive was developed in the 1950s by scientists at Ethyl Corporation.
The use of MMT is allowed in conventional gasoline in the United States, except California, up to a maximum of 1/32 gram of manganese per gallon of gasoline (8.26 mg of Mn per liter of gasoline). The primary product of combustion from MMT in gasoline is Mn₃O₄. About 20% to 30% of manganese oxides formed during combustion comes out from the automobile exhaust in the form of very fine particles. The remaining amount stays and gets deposited in various parts of the engine.
It is an object of this invention to provide a motor fuel additive for MMT containing motor fuels, which is useful in preventing both fuel intake system deposit formation and combustion chamber deposit formation. It is a feature of this invention that the additive comprises a detergent component and a fuel conditioner component, which synergistically interact to reduce both fuel intake system and combustion chamber deposit formation. It is an advantage of this invention that it both reduces deposit formation in engine fuel intake systems and ORI associated with combustion chamber deposit formation.
Another object of this invention is to provide a motor fuel additive for MMT containing motor fuels, which is useful in preventing both fuel intake system deposit formation and combustion chamber deposit formation. It is a feature of this invention that the additive comprises a fuel conditioner component, which synergistically interact to reduce combustion chamber deposit formation. It is an advantage of this invention that it both reduces deposit formation in engine fuel intake systems and ORI associated with combustion chamber deposit formation.
It is another object of this invention to provide a motor fuel additive which reduces deposits in engine fuel intake systems and also reduces the amount of MMT required to increase octane number in gasoline while maintaining engine performance.

SUMMARY OF INVENTION

One object of the present invention is directed to a MMT containing motor fuel additive composition which reduces and modifies combustion chamber deposit formation for the purpose of reducing engine octane requirement increase and allows the use of lower levels of MMT while retaining engine performance comprising a mixture of: (a) a fuel conditioner component comprising: (i) from about 10 to about 90 weight percent, based upon the total weight of the fuel conditioner component, of a polar oxygenated hydrocarbon having an average molecular weight in the range of about 200 to about 500, an acid number in the range of about 25 to about 175, and a saponification number in the range of about 30 to about 250, and (ii) from about 10 to about 90 weight percent, based upon the total of the fuel conditioner component, of an oxygenated compatibilizing agent preferably having a solubility parameter in the range of about 7.0 to about 14.0 and moderate to strong hydrogen capacity, and (b) a MMT compound.
Another object of the present invention is directed to a MMT containing motor fuel additive composition that reduces and modifies both fuel intake system and combustion chamber deposit formation for the purpose of reducing engine octane requirement increase and allows the use of lower levels of MMT while retaining engine performance comprising a mixture of: (a) from about 5 to about 50 weight percent, based upon the total weight of components a and b, of a detergent component selected from the group consisting of (i) a reaction product of: (A) a substituted hydrocarbon of the formula
R₁—X (I)
wherein R₁is a hydrocarbyl radical having a molecular weight in the range of about 150 to about 10,000, and X is selected from the group consisting of halogens, succinic anhydride and succinic dibasic acid, and (B) an amino compound of the formula
H—(NH—(A)_m)_n—Y—R₂ (II)
wherein Y is O or NR₅, R₅being H or a hydrocarbyl radical having 1-30 carbon atoms; A is a straight chain or branched chain alkylene radical having 1-30 carbon atoms; m has a value in the range of 1-15; n has a value in the range of 0-6; and R₂is selected from the group consisting of H, a hydrocarbyl radical having a molecular weight in the range of about 15 to about 10,000, and a homopolymeric or heteropolymeric polyoxyalkylene radical of the formula
R₃—((Q)_a(T)_b(Z)_c)_d— (III)
wherein R₃is H or a hydrocarbyl radical having 1-30 carbon atoms, Q, T, and Z are polyoxyalkylene moieties having 1-6 carbon atoms, a, b and c each have values ranging from 0-30, and d has a value in the range of 1-50, and (ii) a polybutylamine or polyisobutylamine of the formula

where R₁₁is a polybutyl or polyisobutyl radical derived from isobutene and up to 20% by weight of n-butene and R₁₂and R₁₃are identical or different and are each hydrogen, an aliphatic or aromatic hydrocarbon, a primary or secondary, aromatic or aliphatic aminoalkylene radical or polyaminoalkylene radical, a polyoxyalkylene radical or a heteroaryl or heterocyclyl radical, or, together with the nitrogen atom to which they are bonded, form a ring in which further hetero atoms may be present; and (b) a fuel conditioner component comprising: (i) from about 10 to about 90 weight percent, based upon the total weight of components a and b, of a polar oxygenated hydrocarbon having an average molecular weight in the range of about 200 to about 500, an acid number in the range of about 25 to about 175, and a saponification number in the range of about 30 to about 250, and (ii) from about 10 to about 90 weight percent, based upon the total weight of components a and b, of an oxygenated compatibilizing agent preferably having a solubility parameter in the range of about 7.0 to about 14.0 and moderate to strong hydrogen capacity, and (c) a MMT compound.
The fuel conditioner component may additionally comprise a hydrophilic separant such as a glycol monoether. The additive composition may additionally comprise a carrier oil or fluidizer.
This invention is also directed to a MMT containing motor fuel containing the present invention which may be added with the MMT and any other additives or added after the addition of the MMT and any other additives.

DETAILED DESCRIPTION

This invention is in one aspect directed to a MMT motor fuel additive comprising: (a) a detergent component which is selected from the group consisting of (i) the reaction product of a substituted hydrocarbon and an amino compound, (ii) a polybutylamine or polyisobutylamine; (b) a fuel conditioner component comprising a polar oxygenated hydrocarbon compound and an oxygenated compatibilizing agent; and (c) a MMT compound.
Another aspect of the present invention is directed to a MMT motor fuel additive comprising (a) a fuel conditioner component comprising a polar oxygenated hydrocarbon compound and an oxygenated compatibilizing agent; and (b) a MMT compound.
If the reaction product detergent component is employed, the substituted hydrocarbon reactant used to prepare the reaction product is of the formula
R₁—X (I)
wherein R₁is a hydrocarbyl radical having a molecular weight in the range of about 150 to about 10,000, preferably a polyalkylene radical having a molecular weight in the range of about 400 to about 5000, most preferably a polyalkylene radical having a molecular weight in the range of about 600 to about 1500, and X is selected from the group consisting of halogens, preferably chlorine, succinic anhydride and succinic dibasic acid. in one preferred embodiment, R₁—X is a polyisobutenyl succinic anhydride. In another preferred embodiment, R₁—X is a chloropolyisobutylene, The amino compound reactant used to prepare the reaction product is of the formula
H—(NH—(A)_m)_n—Y—R₂ (II)
wherein Y is O or NR₅, R₅being H or a hydrocarbyl radical having 1-30 carbon atoms, preferably 1-22 carbon atoms; A is a straight chain or branched chain alkylene radical having 1-30, preferably 1-15 carbon atoms; m has a value in the range of 1-15, preferably 1-12; n has a value in the range of 0-6, preferably 0-5; and R₂is selected from the group consisting of H, a hydrocarbyl radical having a molecular weight in the range of about 15 to about 10,000, preferably 15 to about 2000, and a homopolymeric or heteropolymeric polyoxyalkylene radical of the formula
R₃—((Q)_a(T)_b(Z)_c)_d— (III)
wherein R₃is H or a hydrocarbyl radical having 1-30, preferably 1-22 carbon atoms, Q, T, and Z are polyoxyalkylene moieties having 1-6 carbon atoms, a, b, and c each have values ranging from 0-30, and d has a value in the range of 1-50, preferably 1-25.
Various preferred embodiments of the amino compound reactant of formula (II) are given in Table 1 below:
Table 1
1. A=CH₂, m=2, n=3, Y=NR₅, R₅=H, R₂=H, yields an amino compound reactant of the formula:
NH₂—(CH₂)₂—NH—(CH₂)₂—NH—(CH₂)₂—NH₂
2. A=CH₂, m=3, n=1, Y=NR₅, R₅=H, R₂=oleyl radical, yields an amino compound reactant of the formula:
NH₂—(CH₂)₃—NH-oleyl
3. A=CH₂, m=6, n=1, Y=NR₅, R₅=H, R₂=H, yields an amino compound reactant of the formula:
NH₂—(CH₂)₆—NH₂
4. A=CH₂, m=12, n=1, Y=NR₅, R₅=H, R₂=H, yields an amino compound reactant of the formula:
NH₂—(CH₂)₁₂—NH₂
5.

yields an amino compound reactant of the formula:
6.

yields an amino compound reactant of the formula:
In another preferred embodiment, R₂is the above-described homopolymeric or heteropolymeric polyoxyalkylene radical of formula (III). As used in this description and in the appended claims, the terms homopolymeric and heteropolymeric refer to polyoxyalkylene compounds, which in the case of homopolymeric compounds contain one recurring polyoxyalkylene moiety, and in the case of heteropolymeric compounds contain more than one recurring polyoxyalkylene moiety, typically having 1-6 carbon atoms, such as ethylene oxide (EO), propylene oxide (PO) or butylene oxide (BO). Thus, for example, in one embodiment R₂may be a homopolymeric polyoxyalkylene radical of the formula
R₃—((EO))_d—
wherein in formula (III), a=I, b=0, c=0, Q=ethylene oxide, and R₃and d are as previously defined. In another embodiment, R₂may be a heteropolymeric polyoxyalkylene radical of the formula
R₃—((EO)_a(PO)_b(BO)_c)_d—
wherein, in formula III, Q=ethylene oxide, T=propylene oxide, Z=butylene oxide, and a, b, c, d and R₃are as previously described.
In yet another preferred embodiment, the above-described amino compound reactant is selected from the group consisting of polyethylene polyamines, polypropylene polyamines and mixtures thereof. In yet another preferred embodiment, such polyamines are monoalkylated.
The reaction product component is preferably prepared by reacting the substituted hydrocarbon R₁—X to the amino compound in a mole ratio in the range of 0.2:1-20:1, more preferably in the range of 0.5:1-10:1. The reaction product component may be prepared under reaction conditions (including e.g. reaction times, temperatures, and reagent proportions) as are well known by those skilled in the art for preparing such amino compound-substituted hydrocarbon reaction products. The method for preparing such reaction products is described, for example, in U.S. Pat. No. 3,172,892 (LeSeur et al.), U.S. Pat. No. 3,438,757 (Honnen et al.), and U.S. Pat. No. 3,443,918 (Kautsky et al.), all of which are incorporated herein by reference.
The detergent compound may also be a polybutylamine or polyisobutylamine of the formula (IV)

where R₁₁is a polybutyl- or polyisobutyl radical derived from isobutene and up to 20% by weight of n-butene, and R₁₂and R₁₃are identical or different and are each hydrogen, an aliphatic or aromatic hydrocarbon, a primary or secondary, aromatic or aliphatic aminoalkylene radical or polyaminoalkylene radical, a polyoxyalkylene radical or a heteroaryl or heterocyclyl radical, or, together with the nitrogen atom to which they are bonded, form a ring in which further hetero atoms may be present.
Compounds of the general formula (IV) and the method of preparation thereof are disclosed, for example, in U.S. Pat. No. 4,832,702 (Kummer et al.), incorporated herein by reference. Compounds of the general formula (IV) are preferably prepared in accordance with the method disclosed in U.S. Pat. No. 4,832,702, wherein an appropriate polybutene or polyisobutene is hydroformylated with a rhodium or cobalt catalyst in the presence of CO and H₂at from about 80-200° C. and CO/H 2 pressures of up to 600 bar, and the oxo product thereby formed is then subjected to a Mannich reaction or amination under hydrogenating conditions, wherein the amination reaction is advantageously carried out at 80-200° C. and under pressures up to 600 bar, preferably 80-300 bar.
The fuel conditioner component employed in admixture with the detergent component to produce the additive of this invention may preferably be the fuel conditioner previously disclosed in U.S. Pat. No. 4,753,661 (Nelson et al.), incorporated herein by reference. This fuel conditioner comprises a polar oxygenated hydrocarbon compound and an oxygenated compatibilizing agent.
The polar oxygenated hydrocarbon portion of the fuel conditioner signifies various organic mixtures arising from the controlled oxidation of petroleum liquids with air. Often these air oxidations of liquid distillates are carried out at a temperature of from about 100° C. to about 150° C. with an organo-metallic catalyst, such as esters of manganese, copper, iron, cobalt, nickel or tin, or organic catalysts, such as tertiary butyl peroxide. The result is a melange of polar oxygenated compounds which may be divided into at least three categories: volatile, saponifiable and non-saponifiable.
The polar oxygenated compounds preferable for use in the present invention may be characterized in a least three ways, by molecular weight, acid number, and saponification number. It is to be appreciated by those skilled in the art that the terms “molecular weight” and “average molecular weight” are synonymous and are herein used interchangeably. It is to be further appreciated that there are several methods of determining the average molecular weight of an organic material and that different methods will produce different results for the same material. Chemically these oxidation products are mixtures of acids, hydroxy acids, lactones, eaters, ketones, alcohols, anhydrides, and other oxygenated organic compounds. Those suitable for the present invention are compounds and mixtures with an average molecular weight between about 200 and about 500, with an acid number between about 25 and about 175 (ASTM-D-974), and a saponification number from about 30 to about 250 (ASTM-D-974-52). Preferably the polar oxygenated compounds of the present invention have an acid number from about 50 to about 100 and a saponification number from about 75 to about 200.
Suitable compatibilizing agents for use in the fuel conditioner component of the instant invention are organic compounds of moderate solubility parameter and moderate to strong hydrogen-bonding capacity. Solubility parameters, δ, based on cohesive energy density are a fundamental descriptor of an organic solvent giving a measure of its polarity. Simple aliphatic molecules of low polarity have a low δ of about 7.3; highly polar water has a high δ of 23.4. Solubility parameters, however, are just a first approximation to the polarity of an organic solvent. Also important to generalized polarity, and hence solvent power, are dipole moment and hydrogen-bonding capacity. Symmetrical carbon tetrachloride and some aromatics with low gross dipole moment and poor hydrogen-bonding capacity have a solubility parameter of about 8.5. In contrast, methyl propyl ketone has almost the same solubility parameter, 8.7, but quite strong hydrogen-bonding capacity and a definite dipole moment. Thus, no one figure of merit alone describes the “polarity” of an organic solvent.
For the practice of the present invention a compatibilizing agent preferably having a solubility parameter from about 7.0 to about 14.0 and moderate to strong hydrogen-bonding capacity. Suitable classes of organic solvents are alcohols, ketones, esters, and ethers.
The fuel conditioner component of this invention may additionally include a hydrophilic separant which decreases the amount of water in the hydrocarbon fuel, thus improving combustion. Suitable separants for practicing the current invention are ethers of glycols or polyglycols, especially monoethers. Monoethers are preferred over diethers in the practice of the present invention.
Examples of such compounds which may be used are the monoethers of ethylene glycol, propylene glycol, trimethylene glycol, alphabutylene glycol, 1,3-butanediol, beta-butylene glycol, isobutylene glycol, tetramethylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, tripropylene glycol, triethylene glycol, tetraethylene glycol, 1,5-pentanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol. Some monoethers include ethylene glycol monophenyl ether, ethylene glycol monomethylether, ethylene glycol monoethyl ether, ethylene glycol mono-(n-butyl) ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-(n-butyl) ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monocyclohexylether, ethylene glycol monobenzyl ether, triethylene glycol monophenethyl ether, butylene glycol mono-(p-(n-butoxy) phenyl) ether, trimethylene glycol mono(alkylphenyl) ether, tripropylene glycol monomethyl ether, ethylene glycol mono-isopropyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, triethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, 1-butoxyethoxy-2-propanol, monophenyl ether of polypropylene glycol having an average molecular weight of about 975 to 1075, and monophenyl ether of polypropylene glycol wherein the polyglycol has a average molecular weight of about 400 to 450, monophenyl ether of polypropylene glycol wherein the polypropylene glycol has an average molecular weight of about 975 to 1075. Such compounds are sold commercially under trade names such as Butyl Cellosolve, Ethyl Cellosolve, Hexyl Cellosolve, Methyl Carbitol, Butyl Carbitol, Dowanol Glycol ethers, and the like.
The composition of this invention may additionally comprise a suitable amount of a carrier oil or fluidizer selected from the group consisting of petroleum-based oils, mineral oils, polypropylene compounds having a molecular weight in the range of about 500 to about 3000, polyisobutylene compounds having a molecular weight in the range of about 500 to about 3000, polyoxyalkylene compounds having a molecular weight in the range of about 500 to about 3000, and polybutyl and polyisobutyl alcohols containing polybutyl or polyisobutyl radicals derived from polyisobutene and up to 20% by weight of n-butene, corresponding carboxylates of the polybutyl or polyisobutyl alcohol, and mixtures thereof. Petroleum based oils which may be employed include top cylinder oils as well as both natural and synthetic naphthenic and paraffinic base stock oils of relatively high viscosity, including so-called Solvent Neutral Oils (SNO) such as SNO-100 to SNO-600. Mineral oils which may be employed include so-called “light” mineral oils, i.e. those petroleum, aliphatic or alicyclic fractions having a viscosity less than about 10,000 SUS at 250° C. A mixture of hydrocarbon fractions may also be employed in place of a base stock. The above-described polybutyl and polyisobutyl alcohols include those disclosed in U.S. Pat. No. 4,859,210 (Franz et al.), incorporated herein by reference. As used in this description and in the appended claims, the terms “carrier oil” and “fluidizer” are interchangeable, as will be readily understood by those skilled in the art.

Given the presence of the many constituents described above, a wide variety of proportions are suitable for the additive composition of this invention. Below a “Useful Range” and a “Preferred Range” are given in weight percent, based upon the total weight of the additive composition:

TABLE 2


Component	Useful Range	Preferred Range

Detergent Component	10-90	20-70
Polar Oxygenated Compound	10-70	20-60
Compatibilizing Agent	10-70	15-40
Hydrophilic Separant	0-40	0-30
Carrier Oil	0-40	0-30

MMT Compound	balance of the additive package is MMT

The additive composition of this invention may be employed in a wide variety of hydrocarbon or modified hydrocarbon (e.g. alcohol-containing or ether containing) fuels for a variety of engines. Preferred motor fuel compositions for use with the additive composition of this invention are those intended for use in spark ignition internal combustion engines. Such motor fuel compositions, comprise a fuel component generally referred to as gasoline base stocks, preferably comprise a mixture of hydrocarbons boiling in the gasoline boiling range, preferably form about 90-450° F. This base fuel may consist of straight chains, branch chains, paraffins, cycloparaffins, olefins, aromatic hydrocarbons, and mixtures thereof. The base fuel may be derived from, among others, straight run naphtha, polymer gasoline, natural gasoline, or from catalytically cracked or thermally cracked hydrocarbons and catalytically reformed stock. The composition and octane level of the base fuel are not critical and any conventional MMT motor base fuel may be employed in the practice of this invention. In addition, the motor fuel composition may additionally comprise other additives typically employed in motor fuels, such as anti-icing additives, upper cylinder lubricating oils, carburetor detergents, anti-corrosion additives, de-emulsifying agents, odor suppressors, and the like.
Throughout the specification, examples and claims the following definitions are used.
Combustion Chamber Deposits (CCD) means deposits formed in the combustion chamber of an engine, due to the deposition of carbonaceous deposits of unburned fuel components and deposits from other additives present in the fuel.
Octane Requirement Increase (ORI) means the increase in octane requirement that results from the build up of combustion chamber deposits. ORI begins to build up as soon as a new engine is started for the first time as CCDs begin to form in the combustion chamber of the engine. ORI reaches equilibrium between 10,000 to 15,000 miles in the life of a new engine. The octane requirement increase is typically 5 8 octane numbers by the time equilibrium is reached.
Octane Number Required (ONR) means the octane level required to provide knock-free operations in a given engine.
Octane Enhancer means components that are added to gasoline to increase octane and to reduce engine knock, such as for example, MMT, alcohol, and MTBE.
The benefits of the present invention are illustrated in the following two examples:
Two pairs of cars have been utilized with:

Car A: one pair with 3.0 L V6 GM engines
Car B: one with 3.3 L Ford engines

Two fuels have been used:
The ORI values, at the end of the 8,000 mile road tests are:

Fuel Fuel + DurAlt

Car A 9.3 2.4 (reduction of 6.3)

Car B 5.2 1.8 (reduction of 3.4)
It is clearly demonstrated that in the presence of manganese in a fuel, DurAlt is able to control the ORI.

Claims

1. A MMT containing motor fuel additive composition which reduces and modifies both fuel intake system and combustion chamber deposit formation for the purpose of reducing engine octane requirement increase and allows the use of lower levels of MMT while retaining engine performance comprising a mixture of: (a) a fuel conditioner component comprising: (i) from about 10 to about 90 weight percent, based upon the total weight of the fuel conditioner component, of a polar oxygenated hydrocarbon having an average molecular weight in the range of about 200 to about 500, an acid number in the range of about 25 to about 175, and a saponification number in the range of about 30 to about 250, and (ii) from about 10 to about 90 weight percent, based upon the total of the fuel conditioner component, of an oxygenated compatibilizing agent preferably having a solubility parameter in the range of about 7.0 to about 14.0 and moderate to strong hydrogen capacity; and (b) a MMT compound.

2. The MMT containing motor fuel additive composition according to claim 1, allowing the MMT to be reduced below 8.26 milligrams of Mn per liter of gasoline while maintaining desired engine performance.

3. The MMT containing motor fuel additive composition according to claim 1, wherein said additive composition is added to the base fuel in an amount of from about 40 ppm to about 1000 ppm.

4. The MMT containing motor fuel additive composition according to claim 1, wherein said additive composition is added to the base fuel containing a detergent in an amount of from about 60 ppm to about 500 ppm.

5. The MMT containing motor fuel additive composition according to claim 1, wherein said additive composition is added to the base fuel simultaneously with any other additives.

6. The MMT containing motor fuel additive composition according to claim 1, wherein said additive composition is added to the base fuel after any other additives has been added.

7. The MMT containing motor fuel additive composition according to claim 1, wherein said MMT compound is present in a amount of from 0.5 to 8.26 milligrams of Mn per liter of gasoline, preferably from 1.0 milligrams to 8.26 milligrams of manganese per liter.

8. A MMT containing motor fuel additive composition which reduces and modifies both fuel intake system and combustion chamber deposit formation for the purpose of reducing engine octane requirement increase and allows the use of lower levels of MMT while retaining engine performance comprising a mixture of: (a) from about 10 to about 90 weight percent, based upon the total weight of components a and b, of a detergent component selected from the group consisting of (i) a reaction product of: (A) a substituted hydrocarbon of the formula

R₁—X (I)

wherein R₁is a hydrocarbyl radical having a molecular weight in the range of about 150 to about 10,000, and X is selected from the group consisting of halogens, succinic anhydride and succinic dibasic acid, and (B) an amino compound of the formula

H—(NH—(A)_m)_n—Y—R₂ (II)

wherein Y is O or NR₅, R₅being H or a hydrocarbyl radical having 1-30 carbon atoms; A is a straight chain or branched chain alkylene radical having 1-30 carbon atoms; A is straight-chain or a branched-chain alkylene radical having 1 30 carbon atoms, m has a value in the range of 1-15; n has a value in the range of 0-6; and R₂is selected from the group consisting of H, a hydrocarbyl radical having a molecular weight in the range of about 15 to about 10,000, and a homopolymeric or heteropolymeric polyoxyalkylene radical of the formula

R₃—((Q)_a(T)_b(Z)_c)_d— (III)

wherein R₃is H or a hydrocarbyl radical having 1-30 carbon atoms, Q, T, and Z are polyoxyalkylene moieties having 1-6 carbon atoms, a, b and c each have values ranging from 0-30, and d has a value in the range of 1-50, and (ii) a polybutylamine or polyisobutylamine of the formula

where R₁₁is a polybutyl or polyisobutyl radical derived from isobutene and up to 20% by weight of n-butene and R₁₂and R₁₃are identical or different and are each hydrogen, an aliphatic or aromatic hydrocarbon, a primary or secondary, aromatic or aliphatic aminoalkylene radical or polyaminoalkylene radical, a polyoxyalkylene radical or a heteroaryl or heterocyclyl radical, or, together with the nitrogen atom to which they are bonded, form a ring in which further hetero atoms may be present; (b) a fuel conditioner component comprising: (i) from about 10 to about 90 weight percent, based upon the total weight of components a and b, of a polar oxygenated hydrocarbon having an average molecular weight in the range of about 200 to about 500, an acid number in the range of about 25 to about 175, and a saponification number in the range of about 30 to about 250, and (ii) from about 10 to about 90 weight percent, based upon the total weight of components a and b, of an oxygenated compatibilizing agent preferably having a solubility parameter in the range of about 7.0 to about 14.0 and moderate to strong hydrogen capacity; and (c) a MMT compound.

9. The MMT containing motor fuel additive composition according to claim 8, wherein said MMT compound is present in a amount of from 0.5 to 8.26 milligrams of Mn per liter of gasoline, preferably from 1.0 to 8.26 milligrams per liter of gasoline.

10. The MMT containing motor fuel additive composition according to claim 8, allowing the MMT to be reduced below 8.26 milligrams of Mn per liter of gasoline while maintaining desired engine performance.

11. The MMT containing motor fuel additive composition according to claim 8, wherein said additive composition is added to the base fuel in an amount of from about 100 ppm to about 1000 ppm.

12. A motor fuel of this invention can comprise refinery streams or refinery streams and ethers, like MTBE or ETBE in the proportion of 0.5% to 17.2% by volume; or refinery streams and alcohols such as methanol or ethanol or isopropyl alcohols and their compatibilizers, in a proportion of 0.5% to 15% by volume.