Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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,l_
pIEBEL FUEL C~OMpOSITInN
This invention concerns a diesel fuel having a reduced
tendency to form deposits in and around the combustion
chambers of diesel engines.
oxidation of fuel and incomplete Combustion results fn
deposition of highly carbonaceous material in and around
the combustion chambers of internal combustion engines.
First, excessive deposits around the tip of fuel injectors
in indirect injection diesel engines can impair engine
performance leading to poor startability, power reduction,
higher noise, higher fuel consumption, etc.. Second,
deposits around the pistons can lead to ring sticking, bore
polishing, etc. leading to power reduction, high oil
consumption, high emissions, etc.. In recent years these
problems have become important because of the increasing
use of i»direct injection die$el engines in passenger cars
particularly those operating at high speeds.
It is therefore desirable to reduce deposits to accept2~ble
levels which do not result in impaired performance: Many
products are known to reduce injector deposits when added
to the fuel, whilst claims have also been made on general
combustion chamber cleanliness.
We have now found that the tendency of diesel fuels to form
deposits in and around the combustion chambers of the
indirect injection diesel engines may be significantly
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reduced by incorporating in the fuel a quaternary ammonium
compound. There exist several patents dating back to the
1950'x, 1960~s and early 1970's (f.e. prior to the
development of the high speed diesel engines) which propose
the addition of quaternary ammonium compounds to distillate
fuels for various functions although there is no suggestion
that the addition of suvh compounds) will reduce the
formation of deposits due to incomplete fuel combustion in
and around combustion chambers.
Examples of such patents include U.S. Patent No 3158647
which disclases the use of quaternary ammonium fatty acid,
phenate, and naphthenate salts in the stabilisation of
distillate fuel oils. This patent relates to the problem
of sludge deposition in distillate fuel oil during storage
at ambient temperatures and the problem of sludge deposits
causing clogging of burnex filters etc.. This patent does
not concern the formation of deposits in and around the
combustion chambers of diesel engines.
U.S. Patents No. 3408813 and 3346353 concern a petroleum
distillate fuel containing an ashless oil soluble polymeric
dispersant stabilising additive and a diaikyl dimethyl
ammonium chloride or a dialkyl dimethyl au~monium nitrite,
respectively) These additives are adapted to prevent the
formation of persistent haze and stable emulsions when the
petroleum distillate fuel is contacted with water during
handling and storage.
,.
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U.S. Patent No 3397970 relates to a petroleum distillate
oil containing a pour point depressing amount of a
copolymer of ethylene and an olefinicaliy unsaturated
aliphatic ester monomer (for example vinyl acetate) ~aaid
copolymer tending to promote the formation of water haze in
said oil, and as an inhibitor of said haze a dimar of
linoleic acid and quaternary ammonium salt selected from
dicocyl dimethyl ammonium chloride and dicocyl dimethyl
ammonium nitrite.
U.S. Patent No 3493354 disoloses a diesel fuel addit.~ve
containing a mayor amount of an organic barium compound in
combination with a minor amount of a quaternary ammonium
salt. The additive promotes the combustion of the fuel,
thereby reducing the proportion of unburned hydrocarbons
and suspended soot particles in the exhaust gases of diesel
engines. The quaternary ammonium salts serves to prevent
the extraction of barium by water with which the additive
or fuel containing the additzve may come into contact.
United Kingdom Patents 973826 and 1076497 relate to using
quaternary ammonium compounds, particularly nitrates as
distillate fuel stabilisers whereas United Kingdom Patent
1432265 proposes their use as antistatic agents together
with polysulphones.
It is one object of the present invention to reduce the
levels of deposits formed in and around the combustion
chambers of diesel engines to acceptable levels withour
impairing performance. It is a further object of the
present invention to produce an improved diesel fuel
compos it~.on .
~~4000~
According to our invention a diesel fuel composition for use
in an indirect injection engine comprises a diesel fuel and a
minor proportion by weight of a quaternary ammonium salt
soluble therein.
Thus, the present invention relates to the use of a minor
proportion by weight of a quaternary ammonium salt soluble in
a diesel fuel for use in an indirect injection diesel engine.
The four residues connected to the quaternary nitrogen atom of
the quaternary ammonium salt are essentially hydrocarbyl
residues. These residues may be similar or dissimilar. They
may be substituted with functional groups or have incorporated
therein functional groups as parts of the hydrocarbyl chain.
Usually one or two of these residues contain at least 6 carbon
atoms while the remaining residues contain less than 6 carbon
atoms. It is preferred that one of the residues contains at
least 8 carbon atoms while the remaining residues contain less
than 6 carbon atoms.
Usually the hydrocarbyl residues are alkyl groups, alkenyl
groups, aryl groups or alkaryl groups. Examples of alkyl
groups containing less than 6 carbon atoms are methyl, ethyl,
isopropyl, propyl and butyl groups. Examples of alkyl groups
containing more than 6 carbon atoms are dodecyl (lauryl),
tetradecyl (myristyl), hexadecyl (cetyl) and octadecyl
(stearyl) groups. Examples of alkenyl groups containing more
than 6 carbon atoms are dodecynyl, tetradecenyl, octadecenyl
(oleyl), and octadecadienyl (linoleyl) groups. The residues
containing more than 6 carbon atoms can be derived from
natural fats and oils,
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for example coconut oil, eoya bean oil; animal tallow and
the like. In such instances thesA residues will consist
essentially of mixod alkyl groups containing 8 to 22 carbon
atoms.
As mentioned above, the hydrocarbyl residues may contain
functional groups. Examples o! functional groups which may
be present in the residues are hydroxy, halide, ester,
amide, ether, amine, and sulphide functions.
It is preferred that the anionic radical is a strong acid
radical. Examples of strong acid radicals u$eful according
to the invention are nitrate, sulphate) ethosulphate,
sulphonate (both alkyl and elkyl$ry~.)~ sulphurised phenate,
carboxylate, and borate. It is also possible to employ
mixtures of anionic radicals.
when the quaternary ammonium compound is a sulphanate it
can be made from:
(1) Alkylbenzene-sulphonic acids or alkyinaphthalene-
sulphonic acids examples of which include
Benzene-sulphonic acids with straight-chain or
branched single or multiple substituted alkyl
radicals with 4-24 (preferably s-20) carbon atoms
in the aromatic nucleus, for example dodecyl-
benzene-sulphonic acid, dinonylbenzene-sulphonic
acid, dadecylnaphthalenesulphonic acid etc.
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(2) Alkane-sulphonic acids including Sulphonic acids
possessing straight-chain or branched alkyl radicals
usually with 10-30 carbon atoms, for example
tetradecyl sulphonic acid etc.
(3) Alkene-sulphonic acids including Sulphonic acids which
have straight-chain or branched alkenyl radicals
usually with 15-30 carbon atoms, for example 2-
eicosenyl sulphonic acid etc.
The sulphonic acids are typically obtained by sulphonation of
alkyl substituted aromatic hydrocarbons, such as those
obtained from the fractionation of petroleum by distillation
and/or extraction, or by the alkylation of an aromatic
hydrocarbon, for example, benzene, toluene, xylene,
naphthalene, diphenyl. The alkylation may be carried out in
the presence of a catalyst with alkylating agents having from
about 3 to more than 30 carbon atoms, such as, for example,
haloparaffins, olefins that may be obtained by dehydrogenation
of paraffins, polyolefins, or, for example, polymers of
ethylene, propylene, butene, etc. The alkaryl sulphonates
usually contain from about 9 to about 20 or more carbon atoms,
preferably from about 16 to about 50 carbon atoms per alkyl
substituted aromatic moiety.
~3~o~oZ
_, _
Quaternary ammonium gulphurfsed phenates ors synthesised
from sulphurised alkylphenola which have the general
structure:
OH ON
,~ S~
R R R
where R is an alkyl radical, n is an integer from 0 to 4
and x is an integer from 1 to 4. The average number of
carbon atoms in all of the R groups is preferably at least
about 9 in order to ensure adequate solubility in oil. The
individual R groups may contain from 5 to 40, preferably s
to 20 carbon atoms. Alkylation of phenol may be carried
out with alkylating agents of the types used to alkylate
aromatic hydrocarbons in the manufacture of alkaryl
sulphonates. Sulphurisation may be by reaction of the
alkyl phenol with sulphur chloride or by reaction with
sulphur. In the latter case, the alkyl phenol is usually
present as the metal salt, although other sulphurisation
promoters may be used, such as amines.
Quaternary ammonium carboxylates are synthesised from:
1 ~~ ono ~
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(i) Monocarboxylia acid$ including
(a) Aliphatic monocarboxylic acids possessing
saturated ox unsaturated straight or branched
chains usually with 0-6 carbon atoms, for example,
formic acid, ac~atic acid, prapionic acid, butyric
acid, valeric acid, caproic acid.
(b) Aromatic monocarboxylic acids with single or
multiple substituted hydrocarbon xadicals
possessing saturated or unsaturated straight or
branched Chains usually with 0-35 (preferably
0-24) carbon atoms in the aromatic nucleus, far
example, benzo~.c acid, 0-toluic acid, m-toluic
acid, p-toluic acid, p-actylbenzaic acid,
p-nonylben2oic acid, dibutylbenzoic acid,
salicylic acid, methyl salicylic acid, ethyl
salicylic acid, octylsalicylic acid,
nonylsalicylic acid, dodecylsalicylic acid,
tetradecylsalicylic acid, octadecylsalicylic acid
etc.
(2) Polycarboxylic acids including
(a) Aliphatic palycarboxylic acids possessing
saturated or unsaturated straight or branched
Chains usually with 0-80 (preferably 0-50) carbon
~~40a0L
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atoms, for example oxalic acid, malonic acid,
succinic acid, glutaric acid, adipic acid, axelaic
acid, sebacic acid, maleic acid, fumaric acid,
tricarballylic acid, polymeric fatty acids
(dimeric acid, trimeric acid etc.), alkenyl
succinic acids (such as polyisobutenylsuccinic
acid), or the anhydrides of such polycarboxylic
acids.
(b) Aromatic polycarboxylic acids with single or
multiple substituted hydrocarbon radicals
possessing saturated or unsaturated straight
or branched chains usually with 0-35
(preferably 0-24) carbon atoms in the
aromatic nucleus, for example phthalic acid,
iso~phtbalic acid, terephthalic acid,
hemimellitic acid, trimellitic acid, trimeric
acid; methyl phthalic acid, dodecylphthalic
acid etc.
Preferred among the carboxylic acids are the simple
monocarboxylic acids (such as formic acid and acetic acid),
and the simple dicarboxylic acids (such as oxalic acid).
Many of the quaternary ammonium salts which may be employed
according to the present invention are commercially
available. It is preferred to use one of those readily
available compounds. Alternatively the quaternary ammonium
compounds can be synthesised in any suitable manner. Since
the method of preparing the quaternary ammonium compounds
is not part of the invention, the preparation of the
compounds will nat be described in detail. It should
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--lo-
be noted, however, that we have two preferred methods for
the synthesis of compounds such as guaternary ammonium
sulphonates, sulphurised phenates and carboxylates.
In the first method a quaternary ammonium hydroxide is
prepared by reacting a guaternary ammonium halide (for
example the chloride) with stn alkali metal hydroxide (tor
example sodium hydroxide) in an alcohol (for example
methanol).
[ R4 N ] ( + ) X ( ~ ? + NaOH -~--~-~-r-s' ( R4 N ] ( + ) OI~i W ) + NaX
After removing the metal halide by filtration the solution
of quaternary ammonium hydroxide is mixed with the acid HA
where A is the desired anion in a suitable solvent and
allowed to react:-
[R4N](+) OH(-) + HA (R4N](+) A(-) + HZO
The rate of reaction may be increased by raising the
reaction temperature above the ambient temperature. Once
the reaction is complete the solvents and water are removed
by distillation.
In the second method the organic acid HA is reacted with a
metal oxide or hydroxide to form the metal salt:
HA + NaOH ----~ NaA + I~20
If the reaction is done in a suitable solvent (for example
heptane or toluene) the water formed during the reaction
may be removed by refluxing the solvent and using a Dean
and Stark trap. Once all the water has been rempved the
solution of the metal salt is treated with a quaternary
ammonium halide:
~~~ooo~
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NaA + (R4NJ(+)C1(-) --~ (R4NJ(+)A(-) + NaCl
The metal halido is removed by filtration and the solvant
is removed by distillation. Alternatively, the solvent can
be removed by distillation and the metal halide filtered
from the final product.
The amount of quaternary ammonium salt which is added to
the diesel fuel is a minor proportion by weight preferably
less than l wt.$ and mo&t preferably 0.000001 to 0.1 wt.$
especially 2 to 200 ppm.
Other additive materials commonly usad in diesel fuel may
also be included in the diesel fuel compositions according
to the present invention. Such other additive materials
may comprise corrosion inhibitors, dyes and the like)
The effect of quaternary ammonium salts employed according
to the present invention on the fouling of injector nozzles
and combustion chamber and piston cleanliness of diesel
engines is illustrated by the following specific examples
in which the following compounds are employed:
Di(2-hydroxyethyl) ethyl octadecenyl ammonium
etho-sulphate (compound A)
GHz - GHa ~ ~H
//
GHQ--CGN~,~ CH = GN tGH~,~ -- ~ - ~N~- GHj ~- l! or~Nz~GN3.
0
G N~, -GNi - oN
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cetyltrimethyl ammonium sulphonate (compound 8)
~s
t~ ~ _
~~' H'~a N - GNa 4 -~ s --
r
~N~ o
Cetyltrimethyl ammonium nonylphenyl sulphide
(compound C)
GH3
cb N~~- N ~ GNP ~ I
G N,,
x ~ ~N~~ GyH~,
Dimethyl dodecyl ethyl z~mmonium etho-sulphate
(compound D)
GN3 0
G~a. ~s~~ '_"_ N~+~ ' CN CN 4 ' s --' O - GH 'G
GNP O
1~~~601.
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Dimethyl ethyl (3-atearyl amino propyl) ammonium
etho-sulphate (compound E)
O GHQ o
G~ H,~e. ~,G - N1~I GHQ, ~- ~I~~ GH~,~ C.N~ ~O-- S-- O - GH,-GNP
il
G N, O
Dimethyl ethyl (3-lauryl amino propyl) ammonium
etho-sulphate (Compound F)
G N~
0
C« N~~ - G - NH - ~Gl~~,~j - N ~ GNx~GN3 , p - ~ --d - GEC-GHQ
car, d
Dicocodimethyl ammonium formats (Campouhd G)
Dicocodimethyl ammonium borate (Compound H)
Dicocodimethyl ammonium nonyl phenyl sulphide
(Compound I)
Dicocdimethyl ammonium oxalate (Compound J)
GNP
r (~
G« N~5 ' N '~ ~rz~~5- ~~1 ooc. .- Gd o~
i
w. GNP ..
134Q~;0~
The effectiveness of quaternary ammonium salt additives on the
coking of injector nozzles in diesel engines was determined
using a Fiat Ritmo engine having the following specification.
Number of Cylinders 4 in line
speed 4500 rpm
Maximum Power 42.66 kw
Bore 83 mrn
Stroke 79.2 mm
Displacement 1.714 litres
Compression Ratio 20.5:1
Oil Volume 5.0 litres
In the tests the engine is run for 60 twenty u~inute cycles to
simulate the urban driving cycle. Each cycle consists of four
minute periods as follows:
(a) 1000 rpm idle 0 BHP 0 Load
(b) 3000 rpm 65% potential speed 27 BHP 40-~45% Max Load
(c) 1600 rpm 35% potential speed ?.2 BHP 35-40% Max Load
(d) 4200 rpm 90% potential speed 42 BHP 70-8-% Max Load
Before and after the engine test the injectors were rated
according to the test method of ISO 4010. This test works
on the principle of a vacuum being maintained across the
injector at a specific needle lift. Tn order to maintain
this vacuum at the desired level the air-flow into the
n ~34a~0~
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injector may vary. This air-flow into the injector is
recorded. The air-flow into the injector becomes less as the
injectors become coked. The results are recorded as the
difference between clean and dirty, i.e. before and after
tests air-flow. The formula used is as follows:
Percent Air Flow = Before Test - After Test x 100
Loss Before Test
In this and the following examples the results presented are
the averages of four results at one specific setting of the
injectors (0.1 mm lift) .
The diesel fuel used in Example 1 was a diesel fuel obtained
from Italy. The compound according to the present invention
tested in this diesel fuel was Compound A. A comparative test
has been carried ut using a typical product already being sold
for injector nozzle cleanliness application (commercial
product). This is an additive of the type described in the EP
Patent No. 0,203,692. It is a mixture of a phenol compound and
a cyclic amide derived from dicarboxylic acid or anhydride.
The results obtained are shown in Table I, attached.
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Examcl~
Th8 ~ftertiEanB~g~Rf ~~t~R~n3~_~t~onium__~alt~_according to
engines was determined using a Fiat Regata engine having
the following specif ioation.
Humber of Cylinders 4 in line
Speed 4600 rpm
Maximum Power 48.00 kw
Bore 82.60 mm
stroke 90.00 mm
Displacement 1.92 litres
Compression Ratio 21:1
Oil Volume 5.7 litres
In the test the engine way x"un for 60 twenty-minute cycles
to simulate the urban driving cycle.
The total duration of 20 hours represents 1,600 km (1,000
miles) of city driving conditions.
Each cycle consisted of four five minute periods as
follows:
(a) 1100 rpm idle o BHP 0 Load
(b) 3120 rpm 65% potential speed 21.1 BHP 40-45% Max Load
(c) 1680 rpm 35% potential speed 9.4 BHP 35-40% Max Load
(d) 4320 rpm 90% potential speed 45.4 BHP 70-80% Hax Load
l~~OnOI
Further test conditions were as lollcws:-
Manifold Air Temperature 26t 2oC
Coolant Outlet 92t 2oC
coolant Temperature difler~nce s-6oC
oil Temperature at 3000 rpm iiot 2oC
Fuei Temperature 48~ 2oC
Exhaust Temperature at 300 rpm 3o0aC
Various aompound~ according to the present invention were tested
in a UK commercial diesel fuel and the results obtained are
presented in Tab7~.e II.
Examp a 3
The tests in this example have been carried out as described for
Example Z. Ag$in, a UK commercial diesel fuel has been
employed. A comparative result obtained with the commercial
additive product mentioned in Example 1 is included in the
attached Table III.
The compounds according to the present invention tested in this
example are set out in Table 3.
.~3~0001
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ANTI-COKING PERFORMANCE IN FIAT RITMO ENGINE TEST
Fuel %FL~W ~OS,~
Base Italian diesel 71.0
Base + 40 ppm or commercial product 44.7
Base 37.5 ppm of compound A 10.0
Fuel % Flow Redaction
Base UK commercial diesel 65-70 (in repeat
tests)
Base + 25 ppm of compound H 48.3
Base + 25 ppm of col~poundC 46.9
Base + 37.5 ppm of compound G 27.0
Base + 3?.5 ppm of compound H 26.8
Base + 37.5 ppm of compound I 8.1
Base + 37.5 ppm of compound J 5.0
~3~0~0~
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glow ~eduotion
Base UK Commercial
Diesel
Base 40 ppm of commercial product
+ 70
Base 50 ppm of compound D 22.7
+
Base 100 ppm of compound D 15.4
+
Base 50 ppm of compound E 20.5
+
