WO2003020853A1

WO2003020853A1 - Gasoline fuel additized with friction modifier and non-metallic and non-overbased detergent for enhanced engine performance

Info

Publication number: WO2003020853A1
Application number: PCT/US2002/027711
Authority: WO
Inventors: Thomas F. Derosa; Benjamin J. Kaufman; Frank J. Deblase; Michael G. Rawdon; Thomas E. Hayden; James R. Ketcham
Original assignee: Texaco Development Corporation
Priority date: 2001-08-30
Filing date: 2002-08-30
Publication date: 2003-03-13

Abstract

The present invention is directed to a fuel additive including the reaction product of a mixture of (1) a polymer prepared from ethylene, at least one C3 to C1O alpha-monoolefin and a polyene selected from non-conjugated dienes and trienes comprising from about 15 to 80 mole percent of ethylene from about 20 to 85 mole percent of said C3 to C1O alpha-monoolefin and from about 0 to 15 mole percent of said polyene and having an average molecular weight ranging from about 5,000 to 30,000, (2) at least one olefinic carboxylic acid acylating agent, and (3) an N-arylphenylenediamine represented by the formula (I) in which R1 is hydrogen, -NH-aryl, -NH-arylalkyl, a branched or straight chain radical having from 4 to 24 carbon atoms that can be alkyl, alkenyl, alkoxyl, aralkyl, alkaryl, hydroxyalkyl or aminoalkyl, R2 is -NH¿2?, -CH2-(CH2)n-NH2, -CH2-aryl-NH2 in which n has a value from 1 to 10 and R?3¿ is hydrogen, alkyl, alkenyl, alkoxyl, aralkyl, or alkaryl radical having 4 to 24 carbon atoms.

Description

GASOLINE FUEL ADDITIZED WITH FRICTION MODIFIER AND NON- METALLIC AND NON-OVERBASED DETERGENT FOR ENHANCED ENGINE PERFORMANCE

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to an engine fuel additive and a method of

preparing the same. In particular, the engine fuel additive is characterized as exhibiting

excellent low temperature solution properties and improving fuel economy.

2. Background of the Invention

Government legislated fuel economy standards have resulted in efforts being

made by both automotive and additive suppliers to enhance the fuel economy of motor

vehicles. One approach to achieve greater fuel efficiency is by lubricant formulation. Fuel

consumption can be reduced either by decreasing the crank case oil viscosity or by reducing

friction at specific, strategic areas of an engine. For example, inside an engine, about 18% of

the fuel's heat value is dissipated through internal friction (bearings, valve train, pistons,

rings, water and oil pumps) while only about 25% is actually converted to (useful) work at

the crankshaft. The piston rings and part of the valve train account for over 50% of the

friction and operate at least part of the time in the boundary lubrication mode during which a

friction modifier (FM) may be effective. If a friction modifier reduces friction of these

components by a third, the friction reduction corresponds to about a 3.0% improvement in the

fuel's heat of combustion and will be reflected in a corresponding fuel economy

improvement. A chemical additive designed to improve engine fuel economy is disclosed in

U.S. Patent No. 4,729,769, the contents of which are incorporated herein by reference. This

patent discloses an additive which is obtained by the reaction of a C₆-C₂₀ fatty acid ester and a

mono- or di-hydroxy hydrocarbon amine. Specifically, the additive is obtained by the

reaction of 0.8 moles of coconut oil with 1.44 moles of diethanolamine (representing a molar

ratio of coconut oil to diethanolamine of 0.555) by heating it at 120°C to 150°C for between 2

and 4 hours. Fuel economy is improved when this reaction product mixture is used as a

gasoline or diesel fuel additive.

U.S. Patent Application Serial No. 09/728,405 filed December 1, 2000, which

is incorporated herein by reference, discloses a fuel additive which exhibits improved low temperature stability and is composed of a mixture of mixed fatty acid esters, a mono or di-

(hydroxy alkyl amine) or mixtures thereof, and a low temperature property enhancing

effective amount of a low molecular weight ester.

Several other patents disclose additives for fuels and lubricants. For example,

U.S. Patent No. 4,320,019 issued to Hayashi, which is incorporated herein by reference,

discloses a multipurpose lubricating additive prepared by the reaction of an interporymer of ethylene and a C₃ to C₈ alpha-monoolefin with an organic carboxylic acid acylating agent to

form an acylating reaction intermediate which is then reacted with an amine. U.S. Patent No.

4,357,250 which is also issued to Hayashi and which is incorporated herein by reference,

discloses additive compositions produced by reacting an ene reaction intermediate from an

olefinic carboxylic acid or derivative thereof and a terpolymer of ethylene, a C.sub.3-8 .alpha.-monoolefin and a non-conjugated diene or triene with a monoamine-polyamine

mixture.

In addition, U.S. Patent No. 4,144,181 issued to Elliot et al, which is

incorporated herein by reference, discloses polymer additives for fuels and lubricants

comprising a grafted ethylene copolymer reacted with a polyamine, polyol or hydroxylamine

and finally re-reacted with an alkaryl sulfonic acid. Also, U.S. Patent No. 4,137,185 issued to

Gardiner et al., which is incorporated herein by reference, discloses a stabilized imide graft of

an ethylene-containing copolymer additive for lubricants.

Furthermore, U.S. Patent Nos. 4,863,263, 5,075,383 and 5,162,086, each of

which are incorporated herein by reference, disclose additive compositions comprising a graft

and an amine-derivatized copolymer prepared from ethylene and at least one C₃ to C,₀ alpha-

monoolefin and, optionally, a polyene selected from non-conjugated dienes and trienes

comprising from about 15 to 80 mole percent of ethylene, from about 20 to 85 mole percent

of C₃ to C₁₀ alpha-monolefin and from about 0 to 15 mole percent of said polyene, said

copolymer having a number average molecular weight ranging from about 5,500 to 50,000

and having grafted thereon at least 1.8 molecules of a carboxylic acid acylating function per

molecule of said copolymer, which have been reacted with at least one olefinic acid

carboxylic acid acylating agent to form a reaction intermediate which is then reacted with an

amino-aromatic polyamine compound.

The engine fuel additive of the present invention is designed to further

improve the fuel economy of such compositions by reducing the carbonaceous deposit. SUMMARY OF THE INVENTION

We have discovered an improved fuel additive that results in improved fuel

economy and in particular, a reduction in carbonaceous deposits during engine running.

In particular, we have discovered that the performance of the above-described

fuel additives can be improved by the addition of a detergent composition which includes:

the reaction product of a first mixture of (1) a polymer prepared from ethylene,

at least one C₃ to C₁₀ alpha-monoolefin and a polyene selected from non-conjugated dienes

and trienes including from about 15 to 80 mole percent of ethylene from about 20 to 85 mole

percent of the C₃ to C₁₀ alpha-monoolefin and from about 0 to 15 mole percent of the polyene and having an average molecular weight ranging from about 5,000 to 30,000, (2) at least one olefinic carboxylic acid acylating agent, and (3) an N-arylphenylenediamine represented by

the formula:

in which R¹ is hydrogen, -NH-aryl, -NH-arylalkyl, a branched or straight chain radical having

from 4 to 24 carbon atoms that can be alkyl, alkenyl, alkoxyl, aralkyl, alkaryl, hydroxyalkyl

or aminoalkyl, R² is -NH₂, -CH₂-(CH₂)„-NH₂, -CH₂-aryl-NH₂ in which n has a value from 1 to

10 and R³ is hydrogen, alkyl, alkenyl, alkoxyl, aralkyl, or alkaryl radical having 4 to 24 carbon atoms. The present invention also provides for an engine fuel composition including a

major portion of a mixture of hydrocarbons and a fuel economy improving effective amount

of an engine fuel additive containing the inventive detergent compound.

DETAILED DESCRIPTION OF THE INVENTION

As noted, the inventive detergent composition may be added to conventional

fuel additives as described herein. In a preferred composition, the inventive detergent composition is added to a prior art composition which exhibits substantially improved low

temperature solution properties.

In such a composition as described above, an additive is prepared including the reaction product of a mixture (hereinafter referred to as "the second mixture") of mixed fatty acid esters, a mono or di-(hydroxy alkyl amine) or mixtures thereof, and a low

temperature property enhancing effective amount of a low molecular weight ester.

This is then mixed with the reaction product of the first mixture of (1) a polymer prepared from ethylene, at least one C₃ to C₁₀ alpha-monoolefin and a polyene selected from non-conjugated dienes and trienes including from about 15 to 80 mole percent

of ethylene from about 20 to 85 mole percent of the C₃ to C₁₀ alpha-monoolefin and from

about 0 to 15 mole percent of the polyene and having an average molecular weight ranging from about 5,000 to 30,000, (2) at least one olefinic carboxylic acid acylating agent, and (3) an N-arylphenylenediamine represented by the formula:

10 and R³ is hydrogen, alkyl, alkenyl, alkoxyl, aralkyl, or alkaryl radical having 4 to 24

carbon atoms.

In the above additive composition, the mixed fatty acid esters preferably

include a mixture of C₆-C₂₀ fatty acid esters, especially those derived from coconut oil. More

preferably, the mixed fatty acid esters include a mixture of C₈-C₁₆ fatty acid esters and most preferably, the mixed fatty acid esters include a mixture of C₁₂ fatty acid esters.

Alternatively, these fatty acids may be characterized by the formula RCOOH

wherein R is an alkyl hydrocarbon group containing 7-15 carbon atoms, preferably 11-13

carbon atoms and even further preferably 11 carbon atoms.

In addition, the mixed fatty acid esters may include a tri-ester such as a

glycerol tri-ester (coconut oil) having structural formula I shown below:

(I) O

I I

H₂C— O-C— R' HC— O-CO— R"

I

H₂C— O--C— R'"

I I o wherein R', R", and R'" are mixtures of aliphatic, olefins or polyolefins.

Furthermore, other examples of fatty acid esters that can be used with the

present invention include the following: glyceryl tri-laurate, glyceryl tri-stearate, glyceryl tri-

palmitate, glyceryl di-laurate, glyceryl mono-stearate, ethylene glycol di-laurate,

pentaerythritol tetra-stearate, pentaerythritol tri-laurate, sorbitol mono-palmitate, sorbitol

penta-stearate and propylene glycol mono-stearate.

In addition, these esters may include those wherein the acid moiety is a

mixture as is typified by those found in natural oils typified by the following type of oils:

coconut, babassu, palm kernel, palm, olive, caster, peanut, rape, beef tallow, lard (leaf), lard

oil and whale blubber.

The preferred ester is coconut oil and the components of coconut oil are shown

below in Tables 1 and 2. In particular, Table 1 shows the saturated acid components of

coconut oil and Table 2 shows the mono- and poly-unsaturated acid components of coconut

oil.

TABLE 1

TABLE 2

The second component of the second mixture is a primary or a secondary a ine which possesses a hydroxy group and has the formula HN(R"OH)₂ H_a wherein R" is a

divalent alkylene hydrocarbon group containing 1-10 carbon atoms and a is 0 or 1.

Preferably, the second component is diethanolamine, CAS Number (111-42-

2), which is a basic alkanolamine containing reactive appendages at each of its three termini.

Diethanolamine (DEA) has structural formula (LI) shown below. (II) CH₂CH₂OH

H-N \ CH₂CH₂OH

In addition, examples of other amines that can be used include ethanolamine,

propanolamine, isopropanolamine, dipropanolamine, di-isopropanolamine, butanolamines

and the like.

The third component of the second mixture of the additive is a low molecular

weight ester which enhances low temperature properties of the additive composition. The

molecular weight ester preferably has an acid moiety represented by the formula RCO-

wherein R is preferably an alkyl or alkenyl hydrocarbon group containing 5-19 carbon atoms.

Further, the acid moiety is preferably selected from the group including caprylic, caproic,

capric, lauric, myristic, palmitic, stearic, oleic, linoleic, etc. It is preferable that the acid is

saturated although unsaturated acid may be present.

Preferably, the reactant bearing the acid moiety may be a natural oil such as

any of the following types of oil: coconut, babassu, palm kernel, palm, olive, castor, peanut,

rape, beef tallow, lard, lard oil, whale blubber, sunflower, etc. Typically, the oils which may

be employed will contain several acid moieties, the number and type varying with the source

of the oil.

Moreover, the acid moiety may be supplied in a fully esterified compound or

one which is less than fully esterified, e.g., glyceryl tri-stearate, glyceryl di-laurate, glyceryl mono-oleate, etc. Esters of polyols including diols and polyalkylene glycols may be

employed such as esters of mannitol, sorbitol, pentaerythritol, polyoxyethylene polyol, etc.

In a preferred embodiment of the additive, the low molecular weight ester has

an acid moiety represented by the formula RCO- wherein R is an alkyl or alkenyl

hydrocarbon group containing from about 3 to 10 carbon atoms. Preferably, the acid moiety

of the low molecular weight ester is selected from the group consisting of caprylic, caproic,

capric and mixtures thereof. Most preferably, the low molecular weight ester is methyl

caprylate, also known as methyl octanoate, CAS Number (111-11-5). Methyl caprylate is the

ester obtained from the reaction of octanoic acid and methyl alcohol and has structural

formula (III) shown below.

(Ill) O

I I

CH₃— (CH₂)₅-C— O--CH₃

Preferably, the second mixture has a molar ratio of amine to total ester content

in the range of from about 10.0 to 1.0 and more preferably in the range of from about 5.0 to

2.2. The term "total ester content" as used herein means the total amount of the total molar

amount of the mixed fatty acid esters and the low molecular weight ester. In addition, the

second mixture preferably has an amide to ester absorbance ratio in the range of from at least

about 2.0 as measured by transmission infrared spectroscopy.

A preferred second mixture is composed of from about 0.1 to about 0.8 moles

of the mixed fatty acid esters, from about 1.0 to about 4.5 moles of the amine and from about

0.01 to about 0.60 moles of the low molecular weight ester. It is more preferable that the amount of mixed fatty acid esters in the reaction mixture is in the range of from about 0.5 to

0.8 moles, the amount of the low molecular weight ester is in the range of from about 0.1 to

about 0.5 moles and the amount of the amine is in the range of from about 1.2 to about 3.2

moles.

The reaction product of the second mixture is prepared by heating the second

mixture for a time period of about from 0.5 to 10.0 hours and at a temperature at from about

60°C to about 250°C to affect the improvement and or enhancement in the low temperature

stability properties. Preferably, the second mixture is heated for a time period of from about

1.5 to about 6.0 hours and at a temperature in the range from about 110°C to about 180°C. It

is even further preferable that the second mixture is heated at a temperature of from about

130°C to about 150°C for a time period of from about 2 to 4 hours.

The first component of the first mixture is a polymer prepared from ethylene,

percent of the C₃ to Cι₀ alpha-monoolefin and from about 0 to 15 mole percent of the polyene

and having an average molecular weight ranging from about 5,000 to 30,000. Preferably, the

polymer is poly(ethylene-co-propylene).

The second component of the first mixture is at least one olefinic carboxylic

acid acylating agent. Preferably, the olefinic carboxylic acid acylating agent is maleic

anhydride. The third component of the first mixture is an N-arylphenylenediamine

represented by the formula:

carbon atoms. Preferably, the N-arylphenylenediamine is N-phenyl-(p-N' -phenyl) diamine.

In a preferred embodiment, the first mixture is prepared by chemically grafting between 0.5 and 5.0 wt % maleic anhydride onto the backbone of a poly(ethylene-co-

propylene) copolymer, which is depicted below, to produce poly[(ethylene-co-propylene)-g- succinic anhydride] or EPSA.

wherein a = 400 to 3,000 and b = 220 to 2,600.

This material is then reacted with N-phenyl-(p-N' -phenyl) diamine in such a manner that the imide content of the product is at least 90% or higher. The reaction product,

poly[(ethylene-g-ρroρylene)-g-N-phenyl-(4-N'-phenyl)-succinimide], is optimally prepared by reacting EPSA and the aromatic amine at 165°C for 2 to 3 hours, under an inert atmosphere. When added to a fuel, the inventive detergent compositions ("additive

compositions") of the present invention exhibit friction modifying and detergent properties at

least as good as those exhibited by prior art compositions.

The additive compositions of the present invention may be added to the base

fuel in sufficient or effective amounts to impart a detergent and friction reducing property to

the mixture. The additive composition is particularly effective in an amount of about 0.002 to

0.2 wt.% (ca. 0.6 to 64 PTB) (PTB stands for pounds per thousand barrels). The preferred

range is from about 0.008 to 0.1 wt.% (ca. 2.7 to 34 PTB), and most preferably, about 0.02 to

0.08 wt.% (ca. 6.4 to 27 PTB). (All wt.% is based on the total weight of the fuel

composition.)

When used in a fuel composition, the base fuel in which the inventive fuel

additive compositions may be used may be a motor fuel composition composed of a mixture

of hydrocarbons boiling in the gasoline boiling range or the diesel fuel boiling range. This

base fuel may contain straight chain or branch chain paraffins, cycloparaffins, olefins and

aromatic hydrocarbons as well as mixtures of these. The base fuel may be derived from

straight-chained naptha, polymer gasoline, natural gasoline, catalytically cracked or thermally

cracked hydrocarbons as well as catalytically reformed stocks. It may typically boil in the

range of about 80° to 450°F and any conventional motor fuel base may be employed in the

practice of the invention. The fuel composition may also contain any of the additives normally

employed in a motor fuel. For example, the base fuel may be blended with anti-knock

compounds, such as tetraalkyl lead compounds, including tetraethyl lead, tetramethyl lead,

tetrabutyl lead, etc., or cyclopentadienyl manganese tricarbonyl, generally in a concentration

from about 0.05 to 4.0 cc. per gallon of gasoline. The tetraethyl lead mixture which is commercially available for automotive use contains an ethylene chloride-ethylene bromide

mixture as a scavenger for removing lead from the combustion chamber in the form of a

volatile lead halide. The motor fuel composition may also be fortified with any of the

conventional additives including anti-icing additives, corrosion-inhibitors, dyes, etc.

The following example is provided to assist in further understanding the

present invention. The particular materials and conditions employed are intended to be

further illustrative of the invention and are not limiting upon the reasonable scope thereof.

EXAMPLE

A series of eight samples of fuel compositions containing were prepared. Two

of the compositions contained the low temperature stability enhanced fuel additive of U.S.

Patent Application Serial No. 09/728,405. (Referred to herein as Modifier No. 1), and a

conventional detergent (referred to herein as Detergent No. 1).

Detergent No. 1 was mixture of:

(a) 28.6 wt % Mannich base HiTEC-4995 manufactured by Ethyl Corporation in Richmond, Virginia; (b) 37.6 wt % polyetheramine detergent manufactured by Huntsman

Corporation in Austin, Texas; and

(c) the remainer, Avjet solvent.

The chemical structure for HiTEC-4995 is:

wherein PLB is polyisobutylene having an M„ between 1,500 to 2,300 AMU.

The chemical structure for the polyetheramine detergent is:

A third composition contained only the conventional detergent and none of the low temperature enhanced fuel additive. Additional samples of each of these compositions were prepared containing the inventive detergent composition poly[(ethylene-g-propylene)-g-

N-phenyl-(4-N'-phenyl)-succinimide] prepared by reacting ρoly(ethylene-co-propylene) with

maleic anhydride in the presence of dicumyl peroxide to prepare poly(ethylene-co- g-succinic anhydride. This was then condensed with N-phenyl-(p-N' -phenyl) diamine at an

elevated .temperature of 160°C to form the detergent compound.

Each of the thus prepared samples was subjected to testing in a Ford 2.3 L

engine as follows:

At the beginning of the test, the engine was cleaned to remove all fuel

related deposits and assembled using cylinder heads that have been rebuilt to the

manufacturers specifications. The intake valves were weighed before being assembled in the cylinder heads. At the end of the tests, the intake valve deposits were quantified by weighing

the deposit formation and by using the CRC intake valve rating scale. Other intake system

components such as ports and runners were rated using the CRC induction system rating scale. Combustion chamber deposit thickness was measured in mils using an eddy

current/magnetic induction thickness measuring device. The test ran for 100 continuous hours as it repeated the two step cycle shown below in Table 3.

TABLE 3

Stage Speed (RPM MAP (mm Hεa Time (minutes^')

1 2000 230 4

2 2000 255 8

The results are shown below in Table 4. TABLE 4

As is readily apparent from Table 4, the addition of the inventive detergent significantly reduced chamber combustion deposits in all of the compositions.

Thus, while there have been described what are presently believed to be the preferred embodiments of the present invention, those skilled in the art will realize that other and further embodiments can be made without departing from the spirit and scope of the invention, and it is intended to include all such further modifications and changes as come within the true scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. A' fuel additive composition comprising:

the reaction product of a first mixture of (1) a polymer prepared from ethylene, at

least one C₃ to C₁₀ alpha-monoolefin and a polyene selected from non-conjugated dienes and

trienes comprising from about 15 to 80 mole percent of ethylene from about 20 to 85 mole

percent of said C₃ to C₁₀ alpha-monoolefin and from about 0 to 15 mole percent of said

polyene and having an average molecular weight ranging from about 5,000 to 30,000, (2) at

least one olefinic carboxylic acid acylating agent, and (3) an N-arylphenylenediamine

represented by the formula:

or aniinoalkyl, R² is -NH₂, -CH₂-(CH₂)„-NH₂, -CH₂-aryl-NH₂ in which n has a value from 1 to

carbon atoms.

2. The composition of claim 1 wherein the polymer is poly(ethylene-co-propylene).

3. The composition of claim 1 wherein the olefinic carboxylic acid acylating agent is

maleic anhydride.

4. The composition of claim 1 wherein the N-arylphenylenediamine is N-phenyl-(p-N* -

phenyl) diamine.

5. The composition of claim 1 wherein the reaction product is poly[(ethylene-g-

propylene)-g-N-phenyl-(4-N' -phenyl)-succinimide] .

6. The composition of claim 1 which further comprises a second mixture of mixed fatty

acid esters, a mono or di-(hydroxy alkyl amine) or mixtures thereof, and a low temperature

property enhancing effective amount of a low molecular weight ester.

7. The composition of claim 6 wherein the second mixture has a molar ratio of amine to

total ester content in the range of from 10.0 to 1.0.

8. The composition of claim 6 wherein the mixed fatty acid esters comprise esters

containing from about 6 to 20 carbon atoms.

9. The composition of claim 6 wherein the mixed fatty acid esters comprise an ester

having the formula ROOH wherein R is an alkyl hydrocarbon containing 7 to 15 carbon

atoms.

10. The composition of claim 6 wherein the mixed fatty acid esters comprise a tri-ester.

11. The composition of claim 6 wherein the mixed fatty acid esters comprise a glycerol

tri-ester.

12. The composition of claim 6 wherein the mixed fatty acid esters are selected form the

group consisting of babassu oil, palm kernel oil, palm oil, olive oil, castor oil, peanut oil, rape

oil, beef tallow oil, lard oil, whale blubber oil and sunflower oil.

13. The composition of claim 6 wherein the amine has the formula HN(R' ' ' OH)₂._aH_a

wherein R" ' is a divalent alkylene hydrocarbon group containing 1-10 carbon atoms, and a is

O or l.

14. The composition of claim 13 wherein the amine is selected from the group consisting

of ethanolamine, diethanolamine, propanolamine, isopropanolamine, dipropanolamine, di-

isopropanolamine, butanolamine, isomers thereof and mixtures thereof.

15. The composition of claim 6 wherein the low molecular weight ester has an acid

moiety represented by the formula R' ' ' 'CO- wherein R" " is an alkyl or alkenol hydrocarbon

group containing from about 3 to 10 carbon atoms.

16. A method for preparing the fuel additive of claim 1 comprising:

reacting (1) a polymer prepared from ethylene, at least one C₃ to C,₀ alpha-monoolefin and a

polyene selected from non-conjugated dienes and trienes comprising from about 15 to 80

mole percent of ethylene from about 20 to 85 mole percent of said C₃ to C₁₀ alpha-monoolefin

and from about 0 to 15 mole percent of said polyene and having an average molecular weight

ranging from about 5,000 to 30,000, (2) at least one olefinic carboxylic acid acylating agent,

and (3) an N-arylphenylenediamine represented by the formula:

from 4 to 24 carbon atoms that can be alkyl, alkenyl, alkoxyl, aralkyl, alkaryl, hydroxyalkyl or aminoalkyl, R² is -NH₂, -CH₂-(CH₂)„-NH₂, -CH₂-aryl-NH₂ in which n has a value from 1 to

carbon atoms, in the presence of a free radical initiator.

17. The method of claim 16 wherein the polymer is poly(ethylene-co-propylene).

18. The method of claim 16 wherein the olefinic carboxylic acid acylating agent is maleic anhydride.

19. The method of claim 16 wherein the N-arylphenylenediamine is N-phenyl-(p-N' - phenyl) diamine.

20. The method of claim 16 wherein the reaction product is poly[(ethylene-g-propylene)-

g-N-phenyl-(4-N' -phenyl)-succinimide] .

21. A method for improving the fuel economy of an engine fuel comprising a major

portion of hydrocarbons comprising adding to the mixture of hydrocarbons, a fuel economy

improving effective amount of the fuel additive of claim 1.

22. A method for improving the fuel economy of an engine fuel comprising a major

improving effective amount of the fuel additive of claim 6.

23. An engine fuel containing a detergent effective amount of the composition of claim 1.