Note: Descriptions are shown in the official language in which they were submitted.
CA 02359723 2001-08-02 i
Fuel Composition
The present invention relates to a fuel composition containing,
as major component, a specific gasoline and, as minor component,
selected gasoline additives.
Carburettors and inlet systems of Otto engines, and also injec-
tion systems for fuel proportioning, are subjected to increasing
load due to contamination caused by dust particles from the air,
unburned hydrocarbon residues from the combustion chamber and
crankcase breather gases passed to the carburettor.
These residues shift the air-to-fuel ratio during idling and in
the lower partial load region, so that the mixture becomes leaner
and combustion less complete and consequently the content of un-
burned or partly burned hydrocarbons in the exhaust gas increases
and the gasoline comsumption rises.
It is known to avoid these drawbacks by using fuel additives for
cleaning the valves and carburettors or injection systems of Otto
engines (cf eg: M. Rossenbeck in "Katalysatoren, Tenside, Miner-
aloladditive", edited by J. Falbe, U. Hasserodt, page 223, G.
Thieme Verlag, Stuttgart 1978).
Furthermore, the problem of valve seat wear occurs in the case of
Otto engines of less recent design when fuelled with unleaded
gasolines. To counteract this, anti-valve-seat-wear additives
based on alkali metal or alkaline earth metal compounds have been
developed.
For trouble-free running, modern Otto engines require automotive
fuels having a complex set of properties which can only be guar-
anteed when use is made of appropriate gasoline additives. Such
gasolines usually consist of a complex mixture of chemical com-
pounds and are characterized by physical parameters. The inter-
relationship between gasolines and appropriate additives in known
fuel compositions is still unsatisfactory as regards their deter-
gent action or their pollution-abating properties and their anti-
valve-seat-wear action.
It is thus an object of the present invention to provide a more
effective gasoline/additive formulation.
Accordingly, we have found a fuel composition which contains, as
major component, a gasoline having an aromatics content of not
more than 42 vol$ and a sulfur content of not more than 150 ppm
CA 02359723 2001-08-02
2
by weight, and, as minor component, at least one gasoline addi-
tive having a detergent action or an anti-valve-seat-wear action,
which gasoline additive contains at least one hydrophobic hydro-
carbon group having a number-average molecular weight (Mn) of from
85 to 20,000 and at least one polar group selected from
(a) monoamino or polyamino groups containing up to 6 nitrogen
atoms, of which at least one has alkaline properties,
(b) nitro groups, optionally combined with hydroxyl groups,
(c) hydroxyl groups combined with monoamino or polyamino
groups, in which at least one nitrogen atom has alkaline
properties,
(d) carboxylic acid groups or the alkali metal or alkaline
earth metal salts thereof,
(e) sulfo groups or the alkali metal or alkaline earth metal
salts thereof,
(f) polyoxy-(C2-C4 alkylene) groups which are terminated by
hydroxyl groups, by monoamino or polyamino groups, in
which at least one nitrogen atom has alkaline properties,
or by carbamate groups,
(g) carboxylate groups,
(h) groups derived from succinic anhydride and containing hy-
droxyl and/or amino and/or amido and/or imido groups and
(i) groups produced by Mannich reaction of substituted phe-
nols with aldehydes and mono- or poly-amines.
The aromatics content of the gasoline is preferably not more than
vol$ and more preferably not more than 38 volt. Preferred
ranges for the aromatics content are from 20 to 42 volt and par-
ticularly from 25 to 40 volt.
40 The sulfur content of the gasoline is preferably not more than
100 ppm by weight and more preferably not more than 50 ppm by
weight. Preferred ranges for the sulfur content are from 0.5 to
150 ppm by weight and particularly from 1 to 100 ppm by weight.
CA 02359723 2001-08-02
3
In a preferred embodiment, the gasoline has an olefin content of
not more than 21 volt, preferably not more than 18 vol$ and more
preferably not more than 10 volt. Preferred ranges for the olefin
content are from 6 to 21 volt and particularly from 7 to 18 volt.
10
In another preferred embodiment, the gasoline has a benzene con-
tent of not more than 1.0 vol$ and preferably not more than
0.9 volt. Preferred ranges for the benzene content are from 0.5
to 1.0 volt and preferably from 0.6 to 0.9 volt.
In another preferred embodiment, the gasoline has an oxygen con-
tent of not more than 2.7 wt~, preferably from 0.1 to 2.7 wt~,
more preferably from 1.0 to 2.7 wt~ and most preferably from 1.2
to 2.0 wt~.
Particular preference is given to a gasoline which has an aromat-
ics content of not more than 38 volt and at the same time an ole-
fin content of not more than 21 volt, a sulfur content of not
more than 50 ppm by weight, a benzene content of not more than
1.0 volt and an oxygen content of from 1.0 to 2.7 wt~.
The content of alcohols and ethers in the gasoline is normally
relatively low. Typical maximum contents are methanol 3 volt,
ethanol 5 vol$, isopropanol 10 volt, tert-butanol 7 volt, isobu-
tanol 10 volt and ethers containing 5 or more carbon atoms in the
molecule 15 volt.
The summer vapor pressure of the gasoline is usually not more
than 70 kPa and preferably not more than 60 kPa (at 37°C).
The research octane number ("RON") of the gasoline is usually
from 90 to 100. A usual range for the corresponding motor octane
number ("MON") is from 80 to 90.
The above characteristics are determined by conventional methods
(DIN EN 228).
The hydrophobic hydrocarbon group in the gasoline additives,
which provides sufficient solubility in the fuel, has a number-
average molecular weight (Mn) of from 85 to 20,000, preferably
from 113 to 10,000 and more preferably from 300 to 5000. Typical
hydrophobic hydrocarbon groups, particularly in conjunction with
the polar groups (a), (c), (h) and (i), are polypropenyl, polybu-
tenyl and polyisobutenyl radicals having molecular weights Mn of
from 300 to 5000, preferably from 500 to 2500 and more preferably
from 750 to 2250.
CA 02359723 2001-08-02
4
The following examples of individual gasoline additives having a
detergent action or an anti-valve-seat-wear effect are mentioned
by way of example.
Additives containing monoamino or polyamino groups (a) are pre-
ferably polyalkene monoamines or polyalkene polyamines based on
polypropylene or highly reactive (ie containing predominantly
terminal double bonds - mostly in the a and ~ positions) or conven-
tional (ie containing predominantly centered double bonds) poly-
butylene or polyisobutylene having a molecular weight Mn of from
300 to 5000. Such additives based on highly reactive polyisobuty-
lene which can be prepared from the polyisobutylene containing up
to 20 wt~ of n-butylene units, by hydroformylation and reductive
amination with ammonia, monoamines or polyamines such as dimethy-
laminopropylamine, ethylenediamine, diethylenetriamine, triethy-
lenetetramine or tetrethylenepentamine, are disclosed, in partic-
ular, in EP-A 244,616. If the synthesis of the additives is based
on polybutylene or polyisobutylene having predominantly centered
double bonds (mostly in the ~ and ypositions) as starting materi-
als, an obvious choice is the synthesis method involving chlo-
rination and subsequent amination, or oxidation of the double
bond with air or ozone to form the carbonyl or carboxyl compound,
with subsequent amination under reductive (hydrogenating) condi-
tions. This amination may be carried out using the same amines as
mentioned above for the reductive amination of hydroformylated,
highly reactive polyisobutylene. Corresponding additives based on
polypropylene are described, in particular, in WO-A 94/24231.
Further preferred additives containing monoamino groups (a) are
the hydrogenation products of the reaction products of polyisobu-
tylenes having an average degree of polymerization P of from 5 to
100 with nitrogen oxides or mixtures of nitrogen oxides and oxy-
gen, as described, in particular, in WO-A 97/03946.
Further preferred additives containing monoamino groups (a) are
the compounds produced from polyisobutylene epoxides by reaction
with amines followed by dehydration and reduction of the amino
alcohols, as described, in particular, in DE-A 196 20 262.
Additives containing nitro groups, optionally combined with hy-
droxyl groups (b), are preferably reaction products of polyisobu-
tylenes having an average degree of polymerization P of from 5 to
100 or from 10 to 100 with nitrogen oxides or mixtures of nitro-
gen oxides and oxygen, as described, in particular, in WO-A
96/03367 and WO-A 96/03479. These reaction products are usually
mixtures of pure nitropolyisobutanes (eg a,~-dinitropolyisobu-
CA 02359723 2001-08-02
tane) and mixed hydroxynitropolyisobutanes (eg a-nitro-~-hydroxy-
polyisobutane).
Additives containing hydroxyl groups combined with monoamino or
5 polyamino groups (c) are in particular reaction products of poly-
isobutylene epoxides, obtainable from polyisobutylene preferably
containing predominantly terminal double bonds and having a mo-
lecular weight Mn of from 300 to 5000, with ammonia or mono- or
poly-amines, as described, in particular, in EP-A 476,485.
Additives containing carboxylic acid groups or the alkali metal
or alkaline earth metal salts thereof (d) are preferably copolym-
ers of Cz-C4o olefins with malefic anhydride having a total molecu-
lar weight of from 500 to 20,000 whose carboxylic acid groups
have been converted entirely or partially to the alkali metal or
alkaline earth metal salts and the remainder of the carboxylic
acid groups has been caused to react with alcohols or amines.
Such additives are disclosed, in particular, in EP-A 307,815.
Said additives mainly serve to prevent valve seat wear and can be
used, as described in WO-A 87/01126, with advantage combined with
conventional fuel detergents such as poly(iso)butylene amines or
polyether amines.
Additives containing sulfo groups or the alkali metal or alkaline
earth metal salts thereof (e) are preferably alkali metal or al-
kaline earth metal salts of an alkyl sulfosuccinate, as de-
scribed, in particular, in EP-A 639,632. Such additives mainly
serve to prevent valve seat wear and can be used with advantage
combined with conventional fuel detergents such as poly(iso)buty-
lene amines or polyether amines.
Additives containing polyoxy-(Cz-C4 alkylene) groups (f) are pre-
ferably polyethers or polyether amines, which are obtained by
reaction of CZ-C6o alkanols, C6-C3o alkanediols, mono- or di-(Cz-C3o
alkyl)amines, (C1-C3o alkyl)cyclohexanols or (C1-C3o alkyl)phenols
with from 1 to 30 mol of ethylene oxide and/or propylene oxide
and/or butylene oxide per hydroxyl group or amino group and, in
the case of polyether amines, by subsequent reductive amination
with ammonia, monoamines or polyamines. Such products are de-
scribed, in particular, in EP-A 310,875, EP-A 356,725, EP-A
700,985 and US-A 4,877,416. In the case of polyethers such prod-
ucts also have flotation oil characteristics. Typical examples
thereof are tridecanol butoxylates or isotridecanol butoxylates,
isononylphenol butoxylates, polyisobutenol butoxylates and poly-
isobutenol propoxylates and the corresponding reaction products
with ammonia .
CA 02359723 2001-08-02
6
Additives containing carboxylate groups (g) are preferably esters
of mono-, di- or tri-carboxylic acids with long-chain alkanols or
polyols, in particular those having a minimum viscosity of 2 mmz/s
at 100°C, as described, in particular, in DE-A 3,838,918. The
mono-, di- or tri-carboxylic acids used can be aliphatic or aro-
matic acids, and suitable ester alcohols yr ester polyols are
primarily long-chain representatives containing, for example,
from 6 to 24 carbon atoms. Typical representatives of these es-
ters are adipates, phthalates, isophthalates, terephthalates and
trimellitates of isooctanol, isononanol, isodecanol and isotride
canol. Such products also have flotation oil characteristics.
Additives containing groups derived from succinic anhydride and
containing hydroxyl and/or amino and/or amido and/or imido groups
(h) are preferably corresponding derivatives of polyisobutenyl
succinic anhydride, which are obtained by reaction of convention-
al or highly reactive polyisobutylene having a molecular weight Mn
of from 300 to 5000 with malefic anhydride by thermal treatment or
via chlorinated polyisobutylene. Of special interest in this re-
spect are derivatives with aliphatic polyamines such as ethylene-
diamine, diethylenetriamine, triethylenetetramine or tetrethyle-
nepentamine. Such gasoline additives are described, in particu-
lar, in US-A 4,849,572.
Additives containing groups (i) produced by Mannich reaction of
substituted phenols with aldehydes and mono- or poly-amines are
preferably reaction products of polyisobutylene-substituted phe-
nols with formaldehyde and mono- or poly-amines such as ethylene-
diamine, diethylenetriamine, triethylenetetramine, tetrethylene-
pentamine or dimethylaminopropylamine. The polyisobutenyl-substi-
tuted phenols can be derived from conventional or highly reactive
polyisobutylene having a molecular weight Mn of from 300 to 5000.
Such "polyisobutylene Mannich bases" are described, in particu-
lar, in EP-A 831,141.
To provide a more precise definition of the individual gasoline
additives mentioned above, the disclosures of the aforementioned
specifications of the prior art are included herein by reference.
The fuel composition of the invention can contain yet other con-
ventional components and additives. Foremost examples thereof are
flotation oils not having any marked detergent action, for exam-
ple mineral flotation oils (base oils), in particular those of
the viscosity class "Solvent Neutral (SN) 500 to 2000", and syn-
thetic flotation oils based on olefin polymers having a molecular
weight Mn of from 400 to 1800, mainly based on polybutylene or
CA 02359723 2001-08-02
7
polyisobutylene (hydrogenated or non- hydrogenated), on
poly(a-olefins or poly(internal olefins.
Suitable solvents or diluents (for use in additive packs) are al-
iphatic and aromatic hydrocarbons, eg solvent naphtha.
Further conventional additives are corrosion inhibitors based,
for example, on film-forming ammonium salts of organic carboxylic
acids or heterocyclic aromatics for nonferrous metal corrosion
protection, antioxidants or stabilizing agents based, for exam-
ple, on amines such as p-phenylenediamine, dicyclohexylamine or
derivatives thereof or phenols such as 2,4-di-tert-butylphenol or
3,5-di-tert-butyl-4-hydroxyphenylpropionic acid, demulsifiers,
antistatic agents, metallocenes such as ferrocene or methylcyclo-
pentadienyl manganese tricarbonyl, lubricity additives such as
specific fatty acids, alkenyl succinates, bis(hydroxyalkyl)fatty
amines, hydroxyacetamide or castor oil and also colorants (la-
bels). Sometimes amines are also added to lower the pH of the au-
tomotive fuel.
Other suitable fuel compositions of the invention comprise, in
particular, blends of the gasoline described above with a mixture
of gasoline additives containing the polar group (f) and corro-
sion inhibitors and/or lubricity improvers based on carboxylic
acids or fatty acids, which can be present as monomeric and/or
dimeric species. Typical mixtures of this type contain polyisobu-
tylene amines combined with alkanol-initiated polyethers such as
tridecanol or isotridecanol butoxylates or propoxylates, polyiso-
butylene amines combined with alkanol-initiated polyether amines
such as reaction products of tridecanol or isotridecanol butoxy-
late with ammonia and alkanol-initiated polyether amines such as
reaction products of tridecanol or isotridecaol butoxylate with
ammonia combined with alkanol-initiated polyethers such as tride-
canol or isotridecanol butoxylates or propoxylates, in each case
combined with said corrosion inhibitors or lubricity improvers.
Said gasoline additives containing the polar groups (a) to (i)
and said other components are metered to the gasoline, where they
become effective. The components or additives can be added to the
gasoline individually or as a previously prepared concentrate
(additive pack).
Said gasoline additives containing the polar groups (a) to (i)
are added to the gasoline usually in an amount of from 1 to
5000 ppm by weight, preferably from 5 to 3000 ppm by weight and
more preferably from 10 to 1000 ppm by weight. The other compo-
CA 02359723 2001-08-02
8
nents and additives mentioned, if desired, are added in conven-
tional amounts.
The fuel composition of the invention surprisingly allows for the
use of distinctly less detergent or anti-valve-seat-wear agent to
achieve the same detergent or pullution-abating action or anti-
valve-seat-wear action as in the case of conventional fuel com-
positions of the prior art. Furthermore when the same amounts of
detergent or anti-valve-seat-wear agent are used in the fuel com-
position of the invention as in conventional fuel compositions
there is achieved, surprisingly, a distinctly better detergent or
pollution-abating or anti-valve-seat-wear action.
Furthermore, the fuel composition of the invention has additional
advantages in that less sedimentation occurs in the combustion
chamber of the Otto engine and less additive migrates to the mo-
tor oil due to fuel dilution.
The invention is illustrated by, but not restricted to, the fol-
lowing examples.
Examples:
The gasolines used were those listed in Table 1 complying to the
specifications stated, where OF 1 stands for a typical commercial
Otto fuel.
Table 1
Grading OF1 (for comparison)OF2 (invention,)
aromatics content 48.4 41.8
[vol%]
benzene content [vol%]2.0 1.0
olefin content (vol%]22.6 7.8
oxygen content [wt%] 0.5 1.7
sulfur content [ppm 245 90
by
weight]
summer vapor pressure78.4 69.3
(at 37C) [kPa]
CA 02359723 2001-08-02
9
Preparation of the fuel compositions
Example 1 (comparative example)
700 mg of a polyisobutylene amine, prepared from highly reactive
polyisobutylene having a molecular weight Mn of 1000 by hydrofor-
mylation and subsequent reductive amination with ammonia and
dilution to equal parts by weight with Clo-C14 paraffin (Kerocom~
PIBA sold by BASF Aktiengesellschaft), were dissolved in 1 kg of
OF1 as indicated in Table 1.
Example 2 (invention)
700 mg of the same polyisobutylene amine as used in Example 1
were dissolved in 1 kg of OF2 as indicated in Table 1.
Example 3 (comparative example)
600 mg of a commercial additive formulation for gasolines, con-
taining a conventional amount of a detergent containing carbamate
groups as in group (f), were dissolved in 1 kg of OF1 as indi-
cated in Table 1.
Example 4 (invention)
600 mg of the same commercial additive formulation for gasolines
as used in Example 3 were dissolved in 1 kg of OF2 as indicated
in Table 1.
Example 5 (comparative example)
400 mg of a commercial additive formulation for gasolines, con-
taining a detergent, prepared by chlorination and subsequent
amination of polyisobutylene having a molecular weight Mn of 950
and having predominantly centered double bonds, were dissolved in
1 kg of OF1 as indicated in Table 1.
Example 6 (invention)
400 mg of the same commercial additive formulation for gasolines
as used in Example 5 were dissolved in 1 kg of OF2 as indicated
in Table 1.
CA 02359723 2001-08-02
Example 7 (comparative example)
750 mg of a commercial additive formulation for gasolines, con-
taining 50 wt~ of the same polyisobutylene amine as used in Exam-
5 ple 1 and also mineral and synthetic flotation oils and corrosion
control agents (Keropur~3222 sold by BASF Aktiengesellschaft) in
conventional amounts, were dissolved in 1 kg of OF1 as indicated
in Table 1.
10 Example 8 (invention)
350 mg of the same commercial additive formulation for gasolines
as used in Example 7 were dissolved in 1 kg of OF2 as indicated
in Table 1.
Example 9 (comparative example)
500 mg of a commercial additive formulation for gasolines, con-
taining 60 wt~ of the same polyisobutylene amine as used in Exam-
ple 1 and also mineral flotation oil and corrosion control means
(Keropur~3233 sold by BASF Aktiengesellschaft) in conventional
amounts, were dissolved in 1 kg of OF1 as indicated in Table 1.
Example 10 (invention)
500 mg of the same commercial additive formulation for gasolines
as used in Example 9 were dissolved in 1 kg of OF2 as indicated
in Table 1.
Example 11 (comparative example)
700 mg of a mixture of 50 wt~ of the same polyisobutylene amine
as used in Example 1 and 50 wt~ of a commercial antiwear additive
(Kerocom~3280 sold by BASF Aktiengesellschaft) were dissolved in
1 kg of OF1 as indicated in Table 1.
Example 12 (invention)
700 mg of the same additive formulation for gasolines as used in
Example 11 were dissolved in 1 kg of OF2 as indicated in Table 1.
CA 02359723 2001-08-02
11
Working tests
Example 13 (comparative example)
Gasoline of Example 1 was examined as regards its suitability for
maintaining a clean inlet system. This was done by carrying out
engine tests in the form of bench tests employing a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below.
Example 14 (invention)
Gasoline of Example 2 was examined as regards its suitability for
maintaining a clean inlet system. This was done by carrying out
engine tests in the form of bench tests on a Mercedes-Benz engine
CEC F-05-A-93. As expected, the deposits on the inlet valves were
distinctly less than the basic value obtained when no additive is
used, as shown in Table 2 below. It was surprising to find that
compared with Example 13 perfect cleaning of the inlet valves is
achieved using the same amount of fuel additive.
Example 15 (comparative example)
Gasoline of Example 3 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below.
Example 16 (invention)
Gasoline of Example 4 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below. It was surprising to
find that compared with Example 15 virtually perfect cleaning of
the inlet valves is achieved using the same amount of fuel addi-
tive.
CA 02359723 2001-08-02
12
Example 17 (comparative example)
Gasoline of Example 5 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below.
Example 18 (invention)
Gasoline of Example 6 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below. It was surprising to
find that compared with Example 17 virtually perfect cleaning of
the inlet valves is achieved using the same amount of fuel addi-
tive.
Example 19 (comparative example)
Gasoline of Example 7 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
vut engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below.
Example 20 (invention)
Gasoline of Example 8 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below. It was surprising to
find that distinctly less fuel additive is required than in Exam-
ple 19 to achieve a similar degree of inlet valve cleanliness.
Example 21 (comparative example)
Gasoline of Example 9 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
CA 02359723 2001-08-02
13
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below.
Example 22 (invention)
Gasoline of Example 10 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below. It was surprising to
find that compared with Example 21 distinctly better cleaning of
the inlet valves is achieved using the same amount of fuel addi-
tive.
Example 23 (comparative example)
Gasoline of Example 11 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-OS-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below.
Example 24 (invention)
Gasoline of Example 12 was examined to determine its suitability
for maintaining a clean inlet system. This was done by carrying
out engine tests in the form of bench tests on a Mercedes-Benz
engine CEC F-05-A-93. As expected, the deposits on the inlet
valves were distinctly less than the basic value obtained when no
additive is used, as shown in Table 2 below. It was surprising to
find that compared with Example 23 distinctly better cleaning of
the inlet valves was achieved using the same amount of fuel addi-
tive.
45
CA 02359723 2001-08-02
14
Table 2
AdditiveDosage [mg/ Deposits
kg] on
the
inlet
valves
[mg/valve]
valve valve valve valve average
1 2 3 4
Ex. 13 700 40 157 7 87 73 (547)
Ex. 14 700 0 0 0 0 0 (239)
Ex. 15 600 19 60 86 34 50 (274)
Ex. 16 600 0 1 0 2 1 (239)
Ex. 17 400 0 75 17 182 69 (402)
Ex. 18 400 0 2 2 0 1 (239)
Ex. 19 750 31 120 111 30 73 (592)
Ex. 20 350 46 68 38 67 55 (239)
Ex. 21 500 181 95 26 68 93 (475)
Ex. 22 500 27 33 14 77 38 (239)
Ex. 23 700 123 12 98 55 72 (558)
Ex. 24 700 82 12 23 22 35 (239)
25
35
(the values in brackets refer to the basic value of the automo-
tive fuel not containing any additive)
