CA1284883C - Fuel compositions - Google Patents

Abstract

ABSTRACT
FUEL COMPOSITIONS

Coking in and around the injector nozzles of indirect injection compression ignition engines is reduced by means of distillate fuel with which has been blended suitable concentrations of:
(a) organic nitrate ignition accelerator, and (b) hydrocarbyl-substituted succinimide or (a) organic nitrate ignition accelerator, (c) hydrocarbyl amine having from 3 to 60 carbons and from 1 to 10 nitrogens, and (d) N,N'-disalicylidene-1,2 diaminopropane, or (b) hydrocarbyl-substituted succinimide or succinamide, (c) hydrocarbyl amine having from 3 to 60 carbons and from 1 to 10 nitrogens, and (d) N,N'-disalicylidene-1,2-diaminopropane.

Also described are such additive mixtures for use in distillate fuels in amounts sufficient to reduce the coking tendencies of such fuels when used in the opera-tion of indirect injection compression ignition engines.

Description

8;~

Thi~ is a divisional application of copending application ~erial no. 470,058, filed December 13, 1984.

~EL COMPOSITIONS

ColnpressLon ignition Ellel compositions and acl(lil:ive mictures oE orgallic nitrate ignition accelerator and hydrocarbyl-subsl:ituted succinlmi.de, in 5 amoullts suEEicient to resist the coking ten-lencies oE
compression ignition fuel compositions when u.sed in the operation oE indirect injection diesel enyines.
Throttling diesel nozæles have recently come into widespread use in indirect injection automotive and lO liyllt-duty diesel truck engines, i.e., compression ignitioll en-Jines in w11ich the ~uel is injected into and ; iynited in a prechamber or swirl chamber. In this way, the ~lame front proceeds Erorn the prechamber into the laryer compression chamber where the combustioll is com-15 pleted. Engilles designed in this manner allow Eor quieter and smoother operation. The Figure oE the Drawill~J illustrates the yeometry oE the typical throttling diesel nozzle (oEten reEerred to as the "pintle nozzle").
UnEortunately, the advent o~ such en~ines has yivell rise to a new problem, that o~ excessive colciny on ~3~3 t1~e critical surfaces oE the injectors that inject fuel into t11e precha1nber or swirl chamber o the engine. In paLticular and with reference to the Figure, the carbon tell(ls to Eill in all oE the available corners and 5 surEaces oE the obturator lO and the Eorm 12 until a smooth pro~ile is achieved. T11e carbon also tends to bloc~ t11e drilled oriice l~ in the injector body 16 a1ld fill up to the seat l8. In scvere cases, carbon builds u~ on the form 12 and the obturator lO to such an extent lO that it interferes with the spray pattern of the fuel issuing from around the perimeter oE orif1ce 14. Such carbon build up or coking oEten results in such undesirdble consequence~s as delayed fuel injection, increased rate oE uel injection, increased rate of 15 co1nbustion chamber pressure rise, and increased engine noise, and can also result in an excessive increase in emission from the engine of unburned hydrocarbons.
~ 1hile low fuel cetane nu1nber is believed to be a rnajor contributing factor to the coking problem, it is 20 not the only relevant Eactor. Thermal and oxidative stability (lacquering tendencies), fuel aromaticity, and such ~uel characteristics as viscosity, surface tensio and relative dens1ty have also been indicated to play a role in the coking problem.
An important contributio1l to the art would be a fuel composition which has enhanced resistance to cokin~

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tendellcies when employed in the operation of indirect injection diesel engines.
In accordance with one of its embodiments, this invention provides distillate fuel for indirect injection compression ignition engines containing at least the combination of (a) organic nitrate ignition accelerator, and (b) hydrocarbyl-substituted succinimide or succinamide, or the combination of (a) organic nitrate ignition accelerator, (c) hydrocarbyl amine having from 3 to 60 carbons and from 1 to 10 n:itrogens and (d) N,N' disalicylidene-1,2-diaminopropane, or the combination of (b) hydrocarbyl-substituted succinimide or succinamide, (c~ hydrocarbyl amine having from 3 to 60 carbons and from 1 to 10 nitrogens and (d) N,N'-disalicylidene-1,2-diaminopropane, said combinations being separately present in an amount sufficient to minimize coking, especially throttling nozzle coking, in the prechambers or swirl chambers of indirect injection compression ignition engines operated on such fuel.
Another embodiment of the present invention is a distillate fuel additive fluid composition comprising (a) orgallic nitrate ignition accelerator, and (b) hydrocarbyl-substituted succinimide or succinamide, or (a) organic nitrate ignition accelera-tor, (c) hydrocarbyl amine having from 3 to ~0 carbons and from 1 to 10 nitrogens and (d) N,N'-rn/

~3~ '3 disalicylidene-1,2~diam.inopropane or tb) hydrocarbyl-substituted succinimide or succinamide, (c) hydrocarbyl amine havirlg from 3 to 60 carbons and from 1 to 10 nitrogens and (d) N,N'-disalicylidene-1,2-diaminopropane~in an amount suEficient to minimize the coking characteristics of such fuel, especially throttling nozzle coking, in the prechambers or swirl chambers of indirect compression ignition engines operated on such fuel.
Since the invention also embodies the opera-tion of an indirect injection compression ignition engine in a manner which results in reduced coking, a still further embodiment of the present invention is a method of inhibiting coking, especially throttling nozzle coking, in the prechambers or swirl chambers of an indirect injection compression ignition engine, which comprises supplying said engine with a distillate fuel containing at least the combination of (a) organic nitrate ignition accelerator, and (b) hydrocarbyl-substitutsd succinimide or succinamide, or the combination of (a) organic nitrate ignition accelerator, (c) hydrocarbyl amine having from 3 to 60 carbons and from 1 to 10 nitrogens and (d) N,N'-disalicylidene-1,2-diaminopropane or the combination of (b) hydrocarbyl-substituted succinimide or succinamide, (c) hydrocarbyl amine having from 3 -to 60 carbons and from 1 to 10 nitrogens and (d) ~, rn/
;

N,~'-disalicyclidene-1,2-diaminopropane, said combina-tions being separately present in an amount sufficiel-t to millimize such coking in an enc~ine operated on such Euel.
A Eeature of this invention is that the combillation oE additives utilized in its practice .is capable oE suppressing cokiny telldencies oE Euels userl to operate indirect injection compression ignition ellgilles. Such bellavior was exhibited in a series oE
stalldard engine dynamorneter tests conducted as des-cribed in Examples I, II and III hereina~ter.
A wide variety of organic nitrate ignition accelerators, componellt (a), may be ernployed in the fuels of this invention. Pre~erred nitrate esters are the aliphatic or cycloali.pllatic nitrates in which the alipllatic or cycloaliphatic group is saturated, con-tains up to about 12 carbons and, optionally, may be substituted ~ith one or more oxygen atoms.
Typical organic nitrates that may be used are 20 methyl nitrate, ethyl nitrate, propyl nitrate, isopropyl nitrate, allyl nitrate, butyl nitrate, isobutyl nitrate, sec-butyl nitrate, tert-butyl nitrate, amyl nitrate, isoamyl nitrate, 2-amyl nitrate, 3-arnyl nitrate, hexyl nitrate, I-leptyl nitrate, 2-heptyl nitrate, octyl 25 nitrate, isooctyl nitrate, 2-ethylhexyl nitrate, nonyl nitrate, decyl nitrate~ undecyl nitrate, dodecyl ~f , ~
' , ' " ' ~3~83 nitrate, cyclopentyl nitrate, cyclohexyl nitrate, methyl-cyclohexyl nitrate, cyclododecyl nitrate, 2-ethoxyethyl nitrate, 2-(2~ethoxy-ethoxy)etllyl nitrate, tetra-hydro~uranyl nitrate, and the like. Mixtures of such materials Inc~y also be used. The preEerred i.gllitiOIl accelerator Eor use in the Euels oE this invention is ;
mixture o octyl nitrates available as ~n article oE
commerce Erom ~thyl Corporation under the trade m~rk DII-3 ic;nition improver.
The hydrocar~yl-substitu~ed succinimides, colnponellt (b? oE the Euels oE this invention, are well kno~ll. They are readily made by Eirst reacting an oleEinically unsaturated hydrocarbon oE the desired moleclllar weight with maleic anhydride to form a hydrocar~yl-substituted succinic anllydride. Reaction temper~tures oE 100-250C are used. l~ith higher hoiling oleEinically-unsaturated hydrocarbons, good results are obtailled at 200-250C. This reaction can be promoted by the addition oE chlorine Typical oleEins include cracked wax oleEins, linear alpha oleEins, branclled ch~in alpha oleEins, polymers and copolylners oE lower oleE;Ils. These include polymers oE ethylene, pro-pylelle, isobutylene, l-hexelle, l-clecene and the like.
UseEul copolylners are ethylene-propylelle copolymers, ethyleile-isobutylene copolymers, propylene-isobutylene copolylners, ethylelle-l-decene copolymers an~ the like.

~' f'~ 3 llydrocarbyl substituents have al$o been l-nade Erom oleEin terpol~mers. Very useEul products have been made ~ ylene-c3 12 alpha ole~in ~ C5-12 conju(~ated diene terpolymers; SIICh as ethylene-propylelle-1,4 hexadiene terpolymer; ethylene-propylell2-],5-cyclooctadielle terpolymer; ethylene-propylelle--norboLI)elle terpolymers and the like.
OE the Eoregoing, by ar the most useEul hydro-car~l substituents are derived Erom butene polymers, especially polymers o isobutylene.
The molecular weight of the hydrocarbyl sub-stituent can vary over a wide ran~Je. It is desirable that the liydrocarbyl group have a molecular weit311t of at least 500. Although there is no critical upper limit, a preferred range is 500-500,000 number avera~e rnolecular ~ei~ht. The more preEerred avera~e molecular weight is 700-5,000 and most pre~erably 900-3,000.
Hydrocarbyl-substituted succinimides and succinami~es are made by reaction oE the desired hyt3rocarbyl-substituted SUCCi.lliC anhydride ~ith an amine havin(~ at least one reactive hydrot3en atom bonded to an arnine nitrot3en atom. Examples oE these are methyl a-nine, dimethyl amine, n-butyl amine, cli-(n-dodecyl) alni.ne, I~-(alninoethyl) piperidine, piperazine, ~-(3-amino-prol~yl) piperazine, and the like.

- ' ' ~ .

PreEerably, the amine has at least one reactive prilnary amine group capable of reacting to ~orm the pr~erred succinimides. Exaln~les of such primary alnin~s are n-octyl amine, N,N-dimethyl-1,3-propane diamitle, I~-(3--alninopropyl) piperazine, 1,6-hexane dialnine, and the like.
llydroxyalkyl amines can also be use-3 to make the suc_lni;nide-succinaJnicle components of the invention wllicll contain some ester grouus. These amines include ethallo]. amine, diethanol amirle, 2-hydroxypropyl amine, ~l-h;~roxyeth~l ethylenedialnine and the like. Such hydroxyalkyl a-nines can ~e made by reacting a lower alkylene oxide, such as ethylene oxide, propylene oxi(3e or l~utylene oxide with a~nmoni.a or a primary or secondary ainine such as ethylene diamine, dethylene triarnine, trietilylene tetrarnine, tetraethylenepentalnille and the like.
A more preferred class oE primary amines used to make the succinimide, succinamide or rnix~ures thereoE
are tlle polyalkylene am.ines. These are polyamines and mixtures of polyamines which have the general. Eormula ~12N-~ R - Nll~ n ~2~383 whereill R i~ a divalent aliphatic hydrocarbon group hclvinc~ 2-4 carbon atoms and n is an integer from 1-10 includillg mixtures of such polyalkylene amines.
In a highly preEerred eml)odiment, the poly-5 a] kylene amlne is a polyethyleneamine containillg 2-6 e~hylelleamine units. These are represented by the above l~orlnula in WiliCIl R is the group ~C112C112- and n has a value oE 2~6.
The amine used to make the succinimide, 10 succinamide or mixture thereoE need not be all alnine. 7 mono or poly-hydroxyalcohol rnay be include~ in the reaction. Such alcohols can be reacted concurrently with the amine or the two alcohol ~and amine may be reacted seyuentially. Use~ul alcohols are methallol, 15 el:hallol, n-dodecanol~ 2-ethyl hexanol, ethylene ~lycol, propylene glycol, diethylene glycol, 2-ethoxy ethanol, trilnethylol propane, pentaerythritol, dipentaerythritol and the like.
Use~ul arnine-alcohol products are described in 20 U.S. 3,1~4,~17~; U.S. 3,576,7~13; U.S. 3,632,511; U.S.
3,~0~1,763; U.S. 3,836,471; U.S. 3,936,480; r~.s.
3,948,B00; U.S. 3,950,341; U.S. 3,957,354; U.S.
3,957,855; U.S. 3,991,098; U.S. 4,071,548 and U.S.
4,173,5~0.
rrhe reactioll between l:he hIdrocarbyl-sub~l:ituted succinic anllydride and the amine can be carried out by .
: ~ , . ~; : . -.

.: ~ . . . :
~- .; . .
., , . ' :

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mixing the compollellts and heating the mixture to atemperature high enougll to cause a reaction to occur but not so high as to cause decolnposition of the reactants or products or the anhydride may be heated to reaction t rnperature ~nd the amine added over an extended period. A useful temperatllre i9 100-250C. ~est resull:s are obtained by conducting the reaction at a temperature high enough to distill out water Eormed in the reaction.
~ preferred succini.nide~succinamide component is availal~le as an article o comlnerce froln the Edwin Cooper Company under the trade mark l-IITEC E-6~. This product comprises a mixture of active ingredients ancl solvent. Thus, when ~ rEc~ E-644 is used as componellt (b) in formulating the ~uels of this lnvelltion, the product as received should be used at a concent~ation oE
at least about 40 PTB (pounds per thousand barrels) -O. 11~36 grams per liter - to insure that the Einished blend contains an adequate quantity of tlle foregoillg ; 20 succini!nide-succinamide ingredient although sm~ller amounts may be success~u]ly employed The nitrate ignition accelerator--component (a)-~sbould be present in an amoullt of at least 100 to lOOO p~rB (pounds per thousan~l barrels3 - 0.2859 to 2. 859 gr~s ~e litrr oE the ~se ~1. PreE-ra 1~, the ~ ~488~3 concelltration oE the ignition acce1erator is 400 to 600 PTB tl.1~36 to 1.715~ grams per liter~.
It is not be1ieved that there is anything critical as regards the maximum amoullt oE compollellts ~a) and (b) used in the Eue1. Thus; the maximum amount oE
tllese components ~ill probably be ~overned in ~ny qiven situatioll by matters oE choice and economics.
The coking-inhibiting components (a) and (b) oE
the invention can be added to the Euels by any means known in the art Eor incorporating small quantities oE
additives into distillate Euels. Components (a) and (b) can be added separately or they can be combined and ac~ded together. It is conveniellt to utilize addikive 1uid mixtures ~/hich consist of orgallic nitrate ignition accelerator and hydrocarhyl-substituted~succi~nimide-.
succinamide agent~s. These additive E1uid mixtures are ~ added to disti11ate uels. In other ~ords, part oE the ; present invention are coking inhibiting 1uids whicl coml)rise oryanic nitrate ignition accelerator and llydrocarby1-substituted succinimide-succinamide.
U.se oE such 1uids in addition to resulting in great convenience ln storage, hand1ing, transportation, blelldillg with fue1s, and so Eorth, also are potent concelltrates ~Ihich serve the Eunct~ion oE inhLbiting or minirni%in~7 the coking char~cteristics oE compressio , :~ :

.

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~ 8~3 ignition distillate fuels used to operate indirect compres~sioll ignition engines.
In these ~luid compositions, the amoullt oE eom-ponellts ~a) and (b) can vary widely. In general, the flu;d compositiolls contain 5 to 95~ by weight Oe the organic nitrate ignition accelerator co~nponellt and 5 I:o 95?~ by weight oE the hydrocarbyl~substitut~3 succinitnide-succinamide componellt. rrypically~ Erom .01 by ~eight up to 1.0% by weight oE the colobination will be suEicient to provide good coking-inhibiting proper-ties to the distillate uel. ~ preEerred distillate fuel composition contains Erom 0.1 to 0. 5% by weight of the combination containing ro~n 253 Lo 95% by weight of the organie nitrate ignition accelerator and Erom 75~ to 5% by weight of the hydrocarbyl~substituted succinimide-succinamide component.
The additive fluids, as ~ell as the distillate fuel compositions o the present invention may also contain other additives such as, corrosion inhibitors, antioxidarlts, metal deactivators, deteryents, cold Elow improvers, inert solvents or diluents, an~l the like.
Accordillgly, a more preferred distillate fuel composition includes a hydrocarbyl amine in combinatio with the present additives.

. . .

. ~ ' ' ~ ' ~ hile a variety oE hydrocarbyl amines may be used in the uel compositions o this lnvention, a primary alipllatic amine, the aliphatic group of which iS
tertiary, e.g., an amine oE the forlnula:

R N~l2 wllereill R is one or a mixture of tertiary aliphatic yroups containiny 8 to 18 or mo~e (preEerably 12-16) carbon atorns is preferred. Most pre~erably, these tertiary aliphatic yroups are tertiary alkyl groups. It 10 is al~so preEerred that hydrocarbyl amine component tc~
inclu~e in addition to the above-depicted amine one or more hydrocarbyl amines differint3 therefrom.
U.s. Pat. ~o. 3,909,215 gives a description oE
the various hydrocarbyl amines having from 3 to 60 ca~bons and ~rorn 1 to 10 nitrogells which may be ernployed in the fuels oE this invention. A few additional exaln~)les of desirable amines include 2,6-di-tert-butyl-~-dirnethylamino-~-cresol, N-cyclohexyl-~dimethylalnine, and N-alkyl,N,N-dimethylamines in which 20 tlle alkyl group is one or a combination o~ alkyl groups preEeral~ly llavin~3 8 to 18 or more carbon atolns.
~ particularly preEerred hydrocarbyl amine is a~ailable commercially ~rom the Rohm and ~laas ~ompany ulltler the trade mark Primene 81R. The Primene ~lR*is * trade maFk ;'. ' :
~ . .

' . . . .

believe~i to be a mixture of primary aliphatic arnines in t/hich ~he aliphatic groups are predomilIalltly C12 an-l C14 tertiary alkyl groups.
~rhe Euels oE this invention should contain at lea.c;t 1.5 to ~0 PTB (0.00429 to 0.11~3 gra,ms/liter Oe compolIent (c), tlIe hydrocarbyl allline.
~ ccordingly, another embo-iirnent oE ~ e present invention is distillate Euel for indirect injection com.oression ignition engines containilIg at least tlIe colnbination oE (a) organic nitrate ignition accelerator, (b) hydrocarbyl-substituted succinimide, a~nd (c) hydLocarbyl amine, said combination being present in an amount suEEicielIt to rninimiæe coking, especially throttling nozzlP coking in the prechambets or swirl chainbers in indirect injectiolI compresslon ign;tion engilIes operated on such fuel.
Also included as a ieurther emhodirnent of the ; invelItion is a distillate euel additive composition comprisilIg (a) organic nitrate ignition accelerator, (b) hydrocarbyl-substituted succinimide and (c) h~dcocarbyl amilIe in an arnount sueEicient to minimize the coking ; characteristics of such Euel, especially throttling nozzle coking in the prechambers or swirl~chambers in in(3irect injection cornpression ignition engines ol~erated on such l~eI.

:. :

- :

~8~ 3 In general, these additive Euel compositions will contain as mllch as 50~ by weight of the combination oE
organic nitrate ignition accelerator and hydrocarbyl-substituted succinimide and up to 50~ of the hydrocarbyl amine or other additives when they are present.
In a still Eurther embodiment of the inv~ntio there is provided a method o~ inhlbiting cokin~3, especially throttling nozzle coking in the prechambers or swirl chambers o an indirect injection compressio 10 ignition engine which comprises supplying said engine ~ith a distillate Euel containin~3 at least the co~-bination oE (a) oryanic nitrate ignition accelerator, (b) hydrocarbyl-substituted succinlmide and (c) hydrocarbyl amine, said combination being present in an ; ~moullt sufficient to minimize such coking in an engine operated on such fuel.
~ nother additive which can be used to advantage in the present invention is a metal deactivator.
I~xamples oE these are salicylidene-o-aminophenol, 20 disallcylidene~ethylenediamine and disalicylidene propylenediamine. ~ particularly pre~erred metal deactivato~ is N~,N'-disalicylidene-1,2-di~minopropalle (80 weight percent active in 20 weight percent toluene solvent) wnich is available as an article of colnmerce ~rom Ethyl CorpO~Ition under tbe tr~de mark . "Ethyl' MDA.

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The fuels of this invention should contain at least 0.2 to 5 PTB (0.00572 to 0.012 grams per liter) o~
comL)onent (d~, the metal deactivator, preferal~ly N,~'-disalicylidene-1,2-diaminopropane.
~ccordin~ly, another ernbodiment oE the present inve!ltiorl is distillate Euel Eor illdirect injection coml?res3ioll ignition en~ines containing at least the cornbination of (a) organic nitrate i~nition accelerator, (b) hydrocarbyl-substituted succinilnide, (c) hydrocarbyl 10 a~ nd (d) N~N~-disalicylidene-l~2-diainillopropane~
said combination being present in an amount su~icient to minimize coking, expecially throttling nozzle coking in the prechambers or swirl chalnbers in indirect injection compressioll ignition engil~es operated on such 15 fuel.
~ lso included as a Eurther embodiment of the invelltion is a distlllate Euel additive colnposition comprising (a) organic nitrate ignition accelerator, (b) hydrocarb,y~l-substituted succinlmide, (c) llydrocarbyl 20 amine, and (d) NtNl-disalicylidelle-lt2-diaminopropalle in an al;~oullt sufficient to minimiæe the coking charac-, teristics of such Euel, especiaily throttling nozzle coking in the precharnbers or swirl chambers of indirect injection compression igllition engines operatcd on such 25 fuels.
; In general, these additive Euel compositions will ~ contain as Inuch as 50~ by weight of the combin.~L all ~f ..

organic nitrate ignition accelerator and hydrocarbyl-substituted succinimide-succinamide and up to 504 of the combination of hydrocarbyl amine and N,N'-disalicylidene-1,2-diamino2ropane or otner addilives when ~hey are 5 presellt.
In a still further ernbodi!nellt oE the invention there is provided a metllod of inhibiting coking, especially throttling nozzle coking in tlle prechambers or swirl chambers in an indirect injectioll colnpression i~nitioll engine which comprises supplying said engine with a distillate fuel containin~ at least the com-binatioll oE (a) organic nitrate ignition accelerator, ~b) hydrocarbyl-substituted succinimide, (c) hydrocarbyl amine and (d) N,N'-disalicylidene-1,2-diaminopropane, 15 said cornbination being present in an amount to minirnize such coking in an en-3ine operated on such Euel.
In another embodiment of tllis invention, the coking-inhibiting components (a), (c) and (d) of the invention can be added to the uels by any means known in the art for incorporating small ~luantitie.s oE
; additives into disLillate ~uels. Compollents (a), (c) and (d) can be added separately or they can be combined and added togetller. It is convenient to ~itilize additive flllid mixtures wllic}l consist oE orgallic nitrate ignition accelerator, hydrocarbyl amine alld met.~l deactivator agents. T}l~se additive fluid rnixtures are .
'' ' ' '' ' '''' '" ' ' .
. ' '' ' adde(l to distillate fuels. In other words, part of the presellt invention are coking inhibiting Eluirls which col~prise organic nitrate ignition accelerator, hy~lrocarbyl amine having Erom 3 to 60 carbons and Erom 1 to l0 nitrogens and metal deactivator, preEerably N,N'-disalicylidene-l,2-dia~nilloprol?ane.
In these Eluid cornposition.s, the amollllt oE
coinL~ollents (a), (c) and (d) can vary widely. In general, the Eluid compositions contain l0 to 97~9~ by 10 weiyht of the organic nitrate ignition accelerator component, 2.0 to 75~ by weigllt oE the hydrocarbyl arnine and 0.l to 15~ by weight metal deactivator. ~ypically, Erom 0.0l~ by weigllt up to l.0~ by weigllt oE the combination of the cornponents (a), (c) and a(d) will be lS suEEicient to provide good coking-inhibitillg properties to the distillate fuel. A preEerred distillate Euel col~osition contalns Erom 0.l to 0.5~ by weigllt of the colnbination containing from 50 to 97.9% b~ weight of the organic nitrate ignitioll accelerator, Erom 2.0 to ~S~ by 20 ~eight of the hydrocarbyl amine and Erom 0.l to 5.0~ by weigllt of the mctal deactivator cornpo1lent.
; In another embodiment of this invention, the co~;in~J-inllibiting components (b), (c~ and (d) of the invention can be added to the Euels b~ any means kno~/n 2S in the art or incorporating slnall quantitie.s oE
addi~ives into distillate Euels. Componellts (b), (c) ~'' . .
~.......................................... . . .

' ~ ~

4~

alld (d) can be added separately or they can be combined alld ~dded to(3ether. It is co~venient to utilize additive Eluid mixtures which consist oE hydrocarbyl-substituted succinimide-succinamide agents, hy~rocarbyl 5 amine and ~I,N'-disalicylidelle-l,2-dialninopropane. rrhese additive Eluid mixtures are added to distillate ~uels.
In otller words, part oE the present invention are coking inhibiting fluids which comprise hydrocarby1-subst~tuted succinimide-succinamide, hydrocarbyl amine having Erom 3 - lO to ~0 carbons and l to lO nitrogens, and metal deacti-vator, preferably N,Nt~disalicylidene-1,2-diaminopropanP.
In these 1uid compositions, the amount OT' components ~b), (c) and (d) can vary widely.~ In general, the Eluid compositions contain lO to 97.9% by 15 weigl1t of the hydrocarb~l-substituted succinimide-succinamide component, 20 to 75% by weight o~ tlle hydrocarbyl amine and O.l to 15% by weight Tnetal deactivator. Typically, from 0 01% by weight up to 1.0 by weigllt oE the combination will be suf~icient to 20 provide good coking-inhibiting properties to the dis-tillate uel. A preEerred distillate fuel composition contains ~rom O.l to 0.5% by we1yht of the combination containing Erom 50~ to 97.9% by weight o~ the hydro-carbyl succlnlmide-succ1namide coïnponent and ~om 2.0~
25 to 45% by weight oE the hydrocarbyl amine and ~rom O.l to 5.0~ by weight oE the metal deactivator, prefera`oly N,~'-disalicylidene-1,2-diaminopropane.

' , ~' --"-..: . ' ' The practice and adv~ntages o~ this invention will become still further apparent from the Eollowing illu<,trative example.
EX~MPLE l In or~er to determine the eEfect of the Euel col:lpositions o the present invention on the coking tcndency o~ diesel injectors in indirect injection compression ignition engines, use was rnade o[ a com-mercial diesel engine operated on a coking test cycle developed by Institute Francais Petrole and as prac-ticed by Peugeot S. ~. Tlle amoUnt of coking togetl-er with a quantitative indication oE the adverse conse-quences of such coking was determined by means of (i) injector air flow perCormance, (ii) emission o~ unburned hydrocarbons, (iii) engine nolse, and (iv) injector deposit ratings. The engine employed in the tests was a .
19~2 Peugeot 2.3 liter, 4-cylinder, turbo-charsed XD2S
diesel engine connected to a MidWest dynamometer through an engine clutch. This engine is equipped with Bosch injectors positioned within prechambers, an(1 is deemed representative of the indirect injection compression i9nitiOIl engines widely used in automobiles and lLght-du~y trucks.
The base Euel employed in these engine tests was a commercially-avai:Lable diesel fuel having a noninal cetane rating of 42. FI~ analysis indicated the Euel .., ~ ', , ~:''' ' ' ' ; ~ , ~3~ 33 was composed by volume oE 31.5~ aromatics,~3.0% olefins and 65.5~ saturates. Its distillation range (ASTM
~-158) l"as as Eollows:

~arometer 29.46 incnes oE llg (0.9987 ~ars) -5 Initial 406F - 207.78C
~vaporated at F - at C
~39 226.11 ~50 232.22 ~56 235.56 ~63 239.
480- 2~8.89 499 259.44 521` 271.67 :
-60 545 2a5.0 572 300.0 ~ 80 ` 603 317.22 ; ~5 621 327.22 643 339.44 G78 ~ 358.89 Final 678F 358.89 Recovery 97.5%
Residue 2.5 1. o s s ; N o n e ' ' ~ ~
: : :::

: . . .

. ' : .

~: .' '., ' ~' - 22 ~

Otller inspection data on the base Euel were as Eollows:
Kinematic Viscosity, (~STM D-445) . . . 3.50 Centi~
sl:o~ s, ~0 C
Pour Point (~slrM D-97)................ -26C
Cloud Point (~STM D-97) ............... 33C
Flash Point (ASTM D-93) . . . . . . . . 91~C
Steam Jet Gum . . . . . . . . . . . . . 2.4 ng/100 ml ~niline Point (AslrM D-611). . . . . . . 143.4F (61.89C) 10 Total Sulur. . . . . . . . . . . . . . 0.41 wt. ~
~amsbottom Carbon, % (AslrM D-524) . . . 0.1~60 on 10%
Residuum Gravity (~STM D-287). . . . . . . . . . 31.8 ~PI
SpeciEic Gravity @ 25C . . . . . . . . 0.~86 Cetane rating . . . . . . . . . . . . . 41 A test blend was prepaced Erom this base Euel (Fuel A). Fuel A contained a combination oE (i) 506 PTB
(1.~47 grams/liter) of mixed octyl nitrates (a com-mercial product availahle ~rom Ethyl Corporation under 20 tlle trade mark DII-3 Ignition Improver), ~ 1 PT3 (0.117 grarn/liter) of HITEC E-644, a product oE Edwin :~Cooper, Inc., believed to be a hydrocarb~l succinimide-succinamide made by reacting two moles oE a polyisobutenyl succinic anbycdricle (PIBSA) lith one mole oE a polyethylene amine rnixture having an average composition corresponding ~to tetraetllylene pentamine, .'~ ' . , ~.

3,3 (iii) 14 PTB (0.0~ grams/liter) oE a hydrocarbyl amine available commercially from Rohm and IIaa.s Colnpany un-ler the trade mark Primene 81~ an(l ( iv~ 1. 7 PT13 ( O. on486 grams/liter) oE Rthyl* Metal neactivatOr, a product oE
Ethyl Corporation, the active ingredieIlt oE whicII is N,~'-disalicylideIle-1,2-diaTnilloproparle. The manu-factu~r gives the Eollowing typical properties for its HIT~C~ E-G4~ product:

.
Appearance . ~ark brown viscou.s ].0 liquid Nitrogen, wt. ~ 2.0 Specific Gravity at 60/60F 0.928 : Viscosity at 210F, cs 340 (98.~9C) The Prlmene 81R*is believed to be a mixture oE
prilnary aliphatic amines in which~the aliphatic grouDs are predominantly~C12 and C14 tertiary alkyl groups.
~ The manufacturer gives the ~ollowing typical : 20 properties-.Eor its Ethyl* metal I)eactivator:

. ~
Form Li~uid Color Amber Density, at 68~
g/IIIl 1.0672 lb/gal ~.91 Active ingredient~ wt % 80 * trade mark :

, ' ' ' , ,:

. : ' . ' -: ~ . , .

8~3 . - 2~ -Solvent vehicle (toluene), wt ~ .20 Elash point, open cup, ~ 8~ (2~.89C) Fire point, F 100 ~37.78C) Solubility In ~asoline (rrypical) Saturated solut:ion contains 9 In water, wt. % 0.04 Sllell Rotella T* an SAE 30, SF/CD oil ~as used as the c.rankcase lubricant.
BeEore starting each test, new soscll DNOSD -1510*nozzles were.installed USill9 new copper gaskets and flame rings.. The ~uel line was ~lushed with the new test uel composition to be tested and the .Euel Eilter bowl and ~uel return reservoir were emptied to avoid additive carry-over roln test-to-test.
~ t the start o each test, the en~ine was operated at 1000 rpm, light load [or 15 minutes. AEter this warm-up, the eng:ine was subjected to the following autolnatic cycle:

.
~ 20 Event llPM Beam Load Minutes EGR
1 750 0 4 oEE
2 2750 12.0 6 on . . .

3 1500 G.2 6 on 4 ~000 16.2 4 oEf * t:rade ma~k ... .

~ 3 The above 20-minute cycle was eepeated fiO times and tlle test was completed by running the engine at idle ~or another 30 minutes. The total elapsed time was thu:, 20.5 hours per test.
When passing Erom one event to the next evellt in the above cycle, some time, oE course, ~as re~ui~ed to enal)le the engine to accelerate or decelerate ~rom one speed to the next. Thus, more specifically, the above cycle was programmed as Eollows:
10SegmentSeconds rprn ;~eam Loa-3 1 2 750 ~0 2 200 750 ~ 0 3 3* 2500 12 4 7* 2750 ~ 12 ` 15 5 35~ 2750 ~ 12 6 3* ~ 2275 6.2 : ~ :
7 7* 1500 6.2 8 330 1500 6.2 9 3* 3500 ` 16.2 7* ~~000 16.2 ; 11 230 ~000 16.2 12 3* ~ 2000 0 13 7* 750 ~ 0 : :
:
25 * i~epresents two mode periods Eor acceleration or ~eceler~tion to the next condition.

. ~' ' , ; .. ' ~ ' : ' `' : ' ~2f~38.3 . - 26 -'Iydrocarbon exllaust emissions were measured at the start o each test (aEter the Eirst 20-minute cycle), at the 6-hour test interval and at the end o~
the test. These measurements were ma-~e at 750, 1000, and 1400 rptn idle. Noise level rea-lings were made at a location tilree ~eet Erom the engine exhaust side. Thc measurelllents were ma~e at the start and at the end oE
the test while operating at three idle speeds, viz., 750, 1000 and 1400 rpm.
After the test operation, the injectors were care~ully removed Eroln the engine so as not to disturb the deposits Eormed thereon. Measurements were made oE
air ~low through each nozzle at diELerent pintle liEts, .
and pintIe deposits were rated using the CRC deposit rating system.

The most signi~lcant test results are given in Table I, in which air Elow is expressed as~cc/min and : ~ :
hydrocarbon emissions as ppm.

TABLE I

Air Flow Pintle Obturator llydrocarbon 20 @ 0.1 mm Deposits ~oise, l)B Emissions Fuel LiEt(10 = clean) EOT* INCT~. EOT* Incr.

, Base 36 8.0 83.8 3.0 577 406 A 38 8.6~ 81.4 1.9 275 143 * Value at end OT- test; the increase (Incr.) shown is in comuarison to the valile at start oE test.
I

', : - :
: ' .,; ~ . :
:
. .
-.: - . . -, .
-, ' . .

~.2~8~3 The results uresented in Tabl~ I show that there were less coking deposits (higi~er air 10w rate and Ee~er deposits), less engine noise and less hydr-ocarbon emissions Witil Fuel A, the fuel oE the invention, as col-npared to the Base Fuel.
E:~AMPLE [I
A test blend was prepared Erom the base fuel of Example I (Fuel B). Fuel 3 contained a coml~ination oE
( i) 506 PTB ( 1.447 grams per liter) of mixed octyl 10. nitrates (a commercial product available ~rom Ethyl Corporation under the trade mark DII~3 Iynition Improver), (ii) 13.2 PTB (0.0377 grams per liter) o a hydrocarbyl amine available commercially from Rohm and ~aas Company under the trade mark Pr~imene 81R and (iii) 1.7 PTB (0. 00486 grams per liter) of Ethyl* Metal eactivator, a product of Ethyl Corporation, the active ingredient of which is ~,N'-disalicylidene-1,2-diamino-propane .
The test engine was operated under the same con-ditlons as those of Exa!nple I.
The most signi~icant test results are given inTa~le II, in which air flow is expressed as cc/min and hydrocarbon emissions as ppm.

* trade mark ' , . , : . , :, ' . ~ .

' : ' ' : '' '; ,. ' : . ' ' ~.2~34~383 T~BEE II

Air Flow Pintle Obturator Hyclrocarbon @ O. 1 mln Deposits Noisel ~N Emissions Fuel Lift (10 = clean) EOT* INC~. EOT* Incr.
_ _ __ __ Base 36 8.0 ~3.8 3.0 577 406 ~3 49 8.~ ~1.3 2.2 282 51 * Value at end oE test; the increa.se (Incr.) shown is in coml7arison to khe value at start of test.

The results presented in Table I~ show that there were less coking deposits (higher alr Elow rate and Ee~er deposits), less engine noise and less hydrocarbon e.nissions with Fuel ~, the Euel oE the lnvention, as com~ared to the Rase Fuel.
:
ExAMprlE III
A test blend was prepared Erom the base fuel oE
xa;nple I (Fuel C). Fuel C contained~a combination oE
(1) 41 PTB (0.117 grams per liter) of NITEC E-644, a product oE Edwin Cooper~ Inc.~ believed to be a hydro-carbyl succinimide-succinamide made by reacting two moles oE a polylsobutenyl succlnlc anhydrlde t~I~SA) with one mole of a polyethylene amine mixture having an average compositlon correspon~.llng to tetraethylelle pentamine, (ii) 14 PTB (0.04 grams per liter) aE a hydrocarbyl amlne available commercially from ~ohm and Haas Cornpany under the t~ad~ mark Primene 81R, and : :
,, -: i .: .

:: : . - . :
.

.

.

liii) 1.7 PTl3 (0.00~8~ grams per liter) o~ Ethylltl~etal l)eactivator, a product o Ethyl Corporation, the active inc3redient o~ wllicll is N,N'-disalicylidelle-1,2-di~millo-p r opa ll e .
The test engine was operated unde the same con-ditions as those oE Example I. The most si~niEicallt test results are given in Table III, in wllich air Elow is e~pressed as cc/min and hydrocarbon emissions as ppm.
' ' , T~BLE III

~ir Flow Pintle Obturator Hydrocarbon ~ 0.1 mm Deposits Noise, Ds Emissions Fuel Lit (10 = clean) EOT* INC~, EO'r* Incr . __ ~ase 36 8.0 83.8 3.0 577 406 C 40 8.5 83!2 3.0 513 278 * Value at end oE test; the increase (Incr.j shown is in comparison to the value at start oE test.

The results presented in Table III show that there were less coking deposits (higher air Elow rate and Eewer deposits), less en~ine noise and less h~clrocarbon emissions with Fuel C, the uel oE the invention, as compared to the Base Fuel.
~ ' ' ..

~ lt tr~de m~k ~., : . .

'' . ~ ~ .

' ~

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Distillate fuel for indirect injection, compression ignition engines, containing the combination of (a) hydrocarbyl-substituted succinimide or succinamide, (b) a hydrocarbyl amine having from 3 to 60 carbons and from one to 10 nitrogens and (c) N,N'-disalicylidene-1,2-diaminopropane, said combination being present in an amount sufficient to minimize coking in the nozzles of indirect injection, compression ignition engines operated on such fuel.

2. The fuel of claim 1, wherein said hydrocarbyl-substituted succinimide is an olefin polymer substituted succinimide, wherein said olefin polymer substituent has an average molecular weight of 500-500,000.
3. The fuel of claim 2, wherein the succinimide portion is derived from a polyalkyleneamine having the general formula:
H2N?-R-NH?H, wherein R is a divalent aliphatic hydrocarbon group having 2-4 carbon atoms and n is an integer from 1-10, including mixtures of the polyalkyleneamines.
4. The fuel of claim 3, wherein said olefin polymer substitutent is a polyisobutene substituent having an average molecular weight of 700-5,000.
5. The fuel of claim 4, wherein said polyalkyleneamine is a polyethyleneamine having 2-6 ethylene amine units.

6. An additive fluid concentrate for use in distillate fuels, containing the combination of claim 1,2,3,4 or 5.

7 . A method of inhibiting coking on the injector nozzles of indirect injection, compression ignition engines, comprising:
supplying the engine with a distillate fuel containing the combination of claim 1,2,3, 4 or 5 and being present in an amount sufficient to minimize such coking in the engine operated on such fuel.