U.S. patent application number 10/127950 was filed with the patent office on 2003-10-23 for fuel stability additive.
Invention is credited to Wolf, Leslie R..
Application Number | 20030196372 10/127950 |
Document ID | / |
Family ID | 29215372 |
Filed Date | 2003-10-23 |
United States Patent
Application |
20030196372 |
Kind Code |
A1 |
Wolf, Leslie R. |
October 23, 2003 |
Fuel stability additive
Abstract
A fuel additive package is disclosed that prevents degradation
of hydrocarbon fuels upon storage and permits extended use of such
motor fuels without intake-valve deposit formation in vehicle
motors. The additive contains an antioxidant, metal deactivator,
corrosion inhibitor, and detergent. The corrosion inhibitor,
preferably a carboxylic acid containing a carbon number equal to or
less than 18 and the detergent component, preferably a
polyisobutylene diamine are selected to avoid antagonistic effects
with the antioxidant and metal deactivator components while the
antioxidant and metal deactivator components are used in markedly
reduced amounts to avoid antagonistic effects resulting in
increased intake-valve deposits.
Inventors: |
Wolf, Leslie R.;
(Naperville, IL) |
Correspondence
Address: |
CAROL WILSON
BP AMERICA INC.
MAIL CODE 5 EAST
4101 WINFIELD ROAD
WARRENVILLE
IL
60555
US
|
Family ID: |
29215372 |
Appl. No.: |
10/127950 |
Filed: |
April 23, 2002 |
Current U.S.
Class: |
44/389 ; 44/412;
44/430 |
Current CPC
Class: |
C10L 1/232 20130101;
C10L 1/238 20130101; C10L 1/143 20130101; C10L 1/1883 20130101;
C10L 1/1832 20130101; C10L 1/2383 20130101; C10L 1/2283 20130101;
C10L 1/223 20130101; C10L 1/1824 20130101; C10L 10/04 20130101;
C10L 1/2222 20130101 |
Class at
Publication: |
44/389 ; 44/412;
44/430 |
International
Class: |
C10L 001/10; C10L
001/22; C10L 001/18 |
Claims
What is claimed is:
1. A stability-enhancing additive package for a hydrocarbon-fuel
comprising: (a) an antioxidant comprising an aromatic amine and a
hindered phenol wherein the aromatic amine is present in the range
of 5.5 to 3.0 weight percent and the hindered phenol is present in
the range of 2.7 to 1.2 weight percent; (b) a metal deactivator
comprising an alkane diamine present in the range of 1.5 to 0.05
weight percent; (c) a corrosion inhibitor comprising a carboxylic
acid having a carbon number of 18 or less; and a (d) detergent
selected from the group consisting of polyalkylene diamine and
polyoxyalkylene diamine.
2. The additive package of claim 1 wherein the carboxylic acid is
present in an amount ranging from 5.0 to 0.5 weight percent.
3. The additive package of claim 1 wherein the detergent is present
in an amount ranging from 15 to 70 weight percent.
4. The additive package of claim 1 wherein the aromatic amine is
N,N'-di-sec-butyl-p-phenylene diamine, the hindered phenol is
2,6-di-t-butyl phenol, the alkane diamine is
N,N'-bis-salicylidene-1,2-pr- opane diamine, the carboxylic acid is
dodecenyl succinic acid, and the detergent is polyisobutylene
diamine.
5. The additive package of claim 4 wherein the dodecenyl succinic
acid is present in an amount ranging from 5.0 to 0.5 weight
percent, and the polyisobutylene diamine is present in an amount
ranging from 15 to 70 weight percent.
6. The additive package of claim 1 wherein the fuel is motor
gasoline.
7. The additive package of claim 6 wherein the gasoline contains
oxygenates such as ethanol, wherein the oxygen content is in the
range of from 0.4 to 5 weight percent of the gasoline.
8. The additive package of claim 6 wherein the gasoline contains
less than 100 ppmw sulfur.
9. The additive package of claim 6 wherein the gasoline contains
less than 50 ppmw sulfur.
10. The additive package of claim 7 wherein the gasoline contains
less than 100 ppmw sulfur.
11. The additive package of claim 1 wherein from 0.25 gallon to 1.0
gallon of the additive package is blended with 1000 gallons of
fuel.
12. The stability-enhancing additive package of claim 1 wherein the
package consists essentially of:
5 N,N'-di-sec-butyl-p- 4.1 wt % phenylene diamine 2,6-di-t-butyl
phenol 1.5 wt % N,N'-bis-salicylidene-1,2- 0.68 wt % propane
diamine Dodecenyl succinic acid 3.0 wt % Polyisobutylene diamine
36.4 wt % detergent Xylene 53.7 wt %
13. A stabilized hydrocarbon fuel comprising a hydrocarbon fuel and
a stability-inducing additive package, wherein the
stability-inducing additive package comprises: (a) from 3.0 to 5.0
weight percent N,N'-di-sec-butyl-p-phenylenediamine; (b) from 1.2
to 2.7 weight percent 2,6-di-t-butyl phenol; (c) from 0.5 to 5.0
weight percent dodecenyl succinic acid; and (d) from 15 to 70
weight percent polyisobutylene diamine.
14. The stabilized fuel of claim 11 wherein the fuel is motor
gasoline.
15. The stabilized fuel of claim 14 wherein the gasoline contains
oxygenates such as ethanol, wherein the oxygen content is in the
range of from 0.4 to 5 weight percent of the gasoline.
16. The stabilized fuel of claim 14 wherein the gasoline contains
less than 100 ppmw sulfur.
17. The stabilized fuel of claim 14 wherein the gasoline contains
less than 50 ppmw sulfur.
18. The stabilized fuel of claim 15 wherein the gasoline contains
less than 100 ppmw sulfur.
19. The stabilized hydrocarbon fuel of claim 13 wherein the
stability-inducing additive package consists essentially of:
6 N,N'-di-sec-butyl-p 4.1 wt % phenylene diamine 2,6-di-t-butyl
phenol 1.5 wt % N,N'-bis-salicylidene-1,2- 0.68 wt % propane
diamine Dodecenyl succinic acid 3.0 wt % Polyisobutylene diamine
36.4 wt % detergent Xylene 53.7 wt %
Description
FIELD OF THE INVENTION
[0001] This invention relates to additives for hydrocarbon fuels.
In one aspect it relates to additives for hydrocarbon fuels which
minimize the degradation of the hydrocarbon fuels upon storage and
permit extended use of such motor fuels in vehicles without deposit
formation. In another aspect it relates to additive-containing
hydrocarbon fuels which maintain their stability during long-term
storage of the fuels and can be used in vehicles without
undesirable intake-valve deposit formation.
BACKGROUND OF THE INVENTION
[0002] After new automobiles, trucks and motor vehicles, in
general, are assembled, their fuel tanks are generally filled to
some extent with an appropriate fuel before the vehicles are
shipped to their point of sale and delivery to the ultimate
customer. Because of the global nature of the motor vehicle
industry, with the assembly of the vehicles often times taking
place in a different part of the world relative to the point of
sale of the vehicle, the fuel that is placed in these fuel tanks
often stands unused for extended periods of time during shipment
and storage of the vehicles. During these periods of time, the fuel
in the fuel tanks, now effectively being in storage, must retain
its initial integrity and not degrade with the degradation
exhibiting itself through subsequent starting and running problems
in the new vehicle and also by the formation of undesirable
deposits in the fuel systems of the vehicles leading to longer term
operability problems. The fuel so used must resist gum and sediment
formation, minimize oxidation and prevent corrosion in the metallic
portions of the fuel system as well as passivate fresh metal
surfaces. Likewise, the fuel storage facilities, for example,
tankage, pumps and plumbing, at the motor vehicle assembly site are
also susceptible to the deposition of these unwanted solid
materials from the quantities of stored motor fuels awaiting
transfer to the newly assembled vehicles.
[0003] The desired stability of the fuel is usually attained
through the addition of appropriate additives to the fresh fuel.
Typically, complex combinations of antioxidants, such as aromatic
diamines or hindered phenols, carboxylic acid-based corrosion
inhibitors, and metallic ion sequesterants such as salicylidene
diamines are added as a stability-inducing package to the fuel. The
term "package" is used typically to indicate the complex
combination of the various stability-inducing materials often times
diluted with a solvent or solvents compatible with the various
individual additive materials and the fuel to be treated. This
package is generally prepared as a separate entity prior to its
addition to the fuel.
[0004] If such a stability-inducing additive package is not
employed, spontaneous deposition of undesirable deposits of solid,
insoluble materials often occurs in the fuel tanks and systems of
the new vehicles. These deposits, also referred to as gum, are
mainly formed from oxidized and/or polymerized hydrocarbons. If a
stability-inducing additive package is employed, gum formation in
new vehicles can be reduced or eliminated.
[0005] U.S. Pat. No. 6,083,288 (Wolf) discloses such a fuel
additive wherein the most-preferred embodiment of the
stability-enhancing package disclosed in Wolf is summarized as
follows:
1 COMPONENT WEIGHT PERCENTAGE N,N'-di-sec-butyl-p- 7.3 phenylene
diamine 2,6-di-t-butyl phenol 2.8 other phenols 0.9
N,N'-bis-salicylidene-1,2- 9.8 propane diamine Amine O Registered
TM 5.2 Xylene 44.0 2-propanol 30.0 TOTAL 100.0
[0006] In this connection, the EPA in accordance with the EPA's
1997 Final Regulation LAC for gasoline detergents requires a
detergent additive to prevent fuel injector fouling and
intake-valve deposits. If the stability-inducing additive package
interacts antagonistically with the detergent, undesirable
intake-valve deposits can form. Generally because only a limited
amount of factory-fill gasoline is used, the antagonistic effect is
not a concern. However if the factory-fill gasoline is used for an
extended period of time, unacceptable amounts of deposit can form.
The present invention permits the extended use of factory-fill
gasoline achieved by careful selection of both the stability
additives and detergent additives to avoid the antagonistic effect
between stability additives and detergent additives. In particular
the present invention will permit drivers to use factory-fill
gasoline for mileage accumulation and pool cars in addition to the
typical newly manufactured vehicle initial fill use.
SUMMARY OF THE INVENTION
[0007] One object of the present invention is to provide a
stability-enhancing additive which can be added to a hydrocarbon
fuel and which minimizes solid deposit and gum formation upon
storage of the fuel and permits the use of such fuel in vehicles
without undesirable intake-valve deposition in the vehicles. A
still further object of the invention is to provide a hydrocarbon
fuel with enhanced stability toward oxidation and solid deposit
formation during storage while concomitantly permitting extended
driving of vehicles using such fuel without intake-valve deposits.
These objects will be attainable through the use of the invention
as described below.
[0008] This invention also uses a combination of aromatic amine and
hindered phenols, and in a preferred embodiment a mixture of
N,N'-dialkyl-p-phenylene diamine and butylated phenols as
stabilizers toward hydrocarbon oxidation. However such antioxidants
are used in markedly reduced amounts compared to the prior art
factory fill fuel. This combination provides for good oxidative
stability for virtually all types of hydrocarbon fuels.
[0009] In addition, this invention in contradistinction to the
prior art includes a substantially reduced amount of a standard
type of metal deactivator, typically alkane diamine, preferably a
salicylidene diamine, to passivate fresh metal surfaces of the fuel
storage vessels and tanks, and the fuel transfer apparatus and to
sequester oxidation-promoting metal ions which may be in the fuel.
It has been found that the subject metal deactivator relatively
greater amounts caused intake valve deposits.
[0010] Additionally, the present invention includes an intake-valve
detergent that is not antagonistic vis--vis the stability
additives. The detergents used in accordance with the present
invention are selected from the group consisting of polyalkylene
diamine and polyoxyalkylene diamine.
[0011] The present invention also includes the use of a corrosion
inhibitor that has been found not to have an antagonistic effect in
contradistinction to the prior use of imizolines. Specifically the
present invention involves the substitution of the imizolines with
carboxylic acids. The detergents used in accordance with the
present invention are selected from the group consisting of
polyalkylene diamine and polyoxyalkylene diamine. More
particularly, the carboxylic acids used in the present invention
have carbon numbers of 18 or less and may be mono or polycarboxylic
acids.
[0012] The present invention employs an aromatic solvent to
solubilize the components of the additive package and to facilitate
the handling and addition of the additive package in concentrations
convenient and appropriate for addition to the hydrocarbon fuel.
Other solvents of mixtures such as alcohols are suitable for use in
the present invention.
[0013] Additionally, this invention includes a fuel composition,
typically, but not limited to, a motor gasoline, to which the
additive package comprising the above described components has been
added and which exhibits enhanced stability, especially toward
solid deposit formation, during storage while concomitantly
permitting extended mileage without causing excessive intake-valve
deposits.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Fuel stabilization additive packages are typically utilized
by adding an amount of the package to fresh fuel such that the
resulting fuel shows no deleterious stability problems over a time
period at least as long as the anticipated storage period. Thus,
the fuel stabilization package of the present invention is added to
fresh fuel, typically, motor gasoline, at the rate of from 0.25
gallon to 1.0 gallon of additive package per 1000 gallons of the
fresh fuel. In this invention, a preferred blending ratio is 0.5
gallon of the additive package per 1000 gallons of the fresh
fuel.
[0015] The fuel additive package of this invention comprises a
combination of stability-enhancing active ingredients added to
inert carrier ingredients. Typically, the concentration of the
active ingredients ranges from 13 weight percent to 78 weight
percent of the final additive package composition with the inert
carrier components concentration ranging from 87 weight percent to
22 weight percent, respectively. Preferably, the active ingredients
represent 26 weight percent of the additive package with the inert
carrier components representing the remaining 74 weight
percent.
[0016] The inert components of the additive package comprise a
mixture of aromatic hydrocarbons and optionally alcoholic solvents
that effectively solubilize the stability-enhancing active
components of the package while at the same time exhibit high
solubility in the fuel to be treated. Constraints of cost,
compatibility with combustion processes, purity and their own
long-term stabilities must be considered when choosing the inert
carrier components. It has been found that mixtures of the various
isomers of xylene can function as one inert component while a
simple aliphatic alcohol, namely 2-propanol, often referred to as
isopropanol, can function as another inert ingredient.
[0017] In addition to the inert carrier component, the
stability-inducing additive package typically contains active
components of four different compound classes, namely,
antioxidants, metal deactivators (often referred to as metal ion
sequesterants) corrosion inhibitors, and deposit control additives
or detergents.
[0018] This invention uses a combination of aromatic amines and
hindered phenols and in a preferred embodiment a combination of
N,N'-dialkyl-p-phenylene diamine and poly-butylated phenols to
provide the antioxidant functionality in the stability-inducing
additive package. This combination has been found to provide good
oxidation stability for virtually all hydrocarbon fuels, including
motor gasoline. The preferred oxidation stabilizers have been
determined to be N,N'-di-sec-butyl-p-phen- ylene diamine and
2,6-di-t-butyl phenol. Lesser amounts of other isomers of the
2,6-di-t-butyl phenol can also be present without impeding the
efficacy of the components. The stability-inducing additive package
typically contains 5.5 to 3.0 weight percent of the aromatic amine
or more preferably N,N'-di-sec-butyl-p-phenylene diamine and 2.7 to
1.2 weight percent of the hindered phenols and more particularly
butylated phenols. The preferred composition of the
stability-inducing additive package contains 4.1 weight percent
N,N'-di-sec-butyl-p-phenylene diamine and 1.5 weight percent
2,6-di-t-butyl phenol with 0.5 weight percent other isomers of this
phenol. These amounts are markedly reduced from the prior art
quantities.
[0019] The metal inactivation (metal ion sequestering)
functionality of the stability-inducing additive package of the
present invention is provided by an alkane amine or more preferably
N,N'-bis-salicyclidene-1,2- -propane diamine. However, due to the
discovery of the antagonistic effect, this metal inactivation
compound is also present in substantially reduced amounts.
Typically this component can be utilized in the practice of this
invention in the 1.5 to 0.05 weight percent range. Preferably, this
component is utilized at the 0.68 weight percentage level in the
additive package to be added to a fuel.
[0020] The corrosion inhibitor additive found to reduce
intake-valve deposition in contradistinction to the use of
imidazoline substituted amidines is a carboxylic acid having a
carbon number of 18 or less. These acids include mono or
polycarboxylic acids, with dodecenyl succinic acid being the most
preferred acid. Typically, this component can be utilized in the
practice of this invention in the 5.0 to 0.5 weight percent range.
Preferably, this component is utilized at the 3.0 weight percentage
level.
[0021] Without wishing to be bound by theory, it is believed that
the imidazoline has an antagonistic on the deposit control
additive. Specifically, the imidazoline reacts with acidic sites on
the valve deposit thereby blocking the deposit control additive
amine and not permitting dissolution. Further, the imidazoline
contributes to the mass of the deposits.
[0022] The detergent additive that provides the desired low
intake-valve deposition is selected from the group consisting of
polyalkylene diamine and polyoxyalkylene diamine.
[0023] In a preferred embodiment, the detergents of the present
invention may be:
[0024] Polyisobutylene amine: A--(C.sub.4H.sub.8).sub.n--X--NHR n=7
to 100, R.dbd.H or A--(C.sub.4H.sub.8).sub.n--X, A and X are small
groups (H or lower alkyl or branched alkyl or aryl) that may
contain heteroatoms (O, N, S) to facilitate linking or initiation;
or
[0025] Polyisobutylene diamine:
A--(C.sub.4H.sub.8).sub.n--X--NH--CH.sub.2- CHA--NHR, n=7 to 100,
R, A, X as defined above; or
[0026] Polyether amine: R(CH.sub.2CHR'--O).sub.n--X--NH.sub.2; n=2
to 100; R.dbd.R" C.sub.6H.sub.4--O, R".dbd.C8 to 24 hydrocarbyl;
R'.dbd.H, CH.sub.3, C.sub.2H.sub.5; X as defined above, with the
diamine being the most preferred.
[0027] Typically, this component can be utilized in the practice of
this invention in the 15 to 70 weight percent range. Preferably,
this component is utilized at the 36.4 weight percent level.
[0028] The most-preferred embodiment of the stability-enhancing
package of this invention is summarized as follows:
2 COMPONENT WEIGHT PERCENTAGE N,N'-di-sec-butyl-p- 4.1 phenylene
diamine 2,6-di-t-butyl phenol 1.5 other phenols 0.5
N,N'-bis-salicylidene-1,2- 0.68 propane diamine Dodecenyl succinic
acid 3.0 Polyisobutylene diamine detergent 36.4 Mixed Xylene 53.72
Demulsifier 0.1 TOTAL
[0029] This mixture is added to commercial gasoline at the rate of
0.5 gallons per 1000 gallons of gasoline to give a highly
stabilized gasoline. The additive can be used with the low sulfur
containing fuels, ethanol containing fuels, and reformulated
gasoline such as Phase II gasoline. More particularly, the motor
fuel can be gasoline containing ethanol or other oxygenates such
that the oxygen content is in the range of 0.4 to 5 weight percent
or more. Additionally, the motor fuel can be gasoline containing
less than 100 ppmw, less than 80 ppmw, less than 50 ppmw or less
than 30 ppmw sulfur. Further, the motor fuel can be a gasoline that
contains oxygen in the range of 0.4 to 5 weight percent or more and
has less than 100 ppmw sulfur.
EXAMPLE
[0030] The present example shows how the additive formulation in
accordance with the present invention provides superior intake
valve deposit performance over the prior art additive packages and
other comparative additive packages.
[0031] Engine Intake Valve Deposit Tests, "IVD tests" were run
essentially according to ASTM D 6201-97, "Standard Test Method for
Dynamometer Evaluation of Unleaded Spark-Ignition Engine Fuel for
Intake Valve Deposit Formation". These tests were carried out on
regular unleaded fuels containing additives in accordance with the
present invention and fuels containing comparative additives.
Briefly, this test uses a 1994 Ford 2.3 L in-line, four cylinder
engine connected to a dynamometer. The engine is built to rigid
specifications using new, weighed intake valves. A rigorous quality
control procedure is used to verify operation and key parameters
are monitored during the test period to ensure repeatability of the
procedure. The fuel system is flushed and filled with new test
fuel. The engine is operated at two modes, the first being 2000 rpm
and 230 mm Hg manifold absolute pressure for 4 minutes and the
second being 2800 rpm at 540 mm Hg manifold absolute pressure for 8
minutes. There is a 30 second ramp between the stages. The two
stages are repeated until 100 hours testing time elapses. After the
test time, the intake valves are removed and weighed to determine
the amount of deposit formed. Initial testing indicated that
relatively good correlation of intake valve deposits between
shorter testing time (24 hours) and the standard 100 hours test
could be obtained. Therefore, for some tests, the procedure was
modified to stop the test after 24 hours and extrapolate (i.e.,
multiply by 4) the deposits to 100 hours so that all tests could be
compared on the same basis.
[0032] The fuels used in the present example were treated at the
level of 0.5 gallons additive per 1000 gallons gasoline.
[0033] Table I sets out the trade names, applications, and
commercial sources for the various components used in the
comparative and invention additives.
3Table I Component Material Function Trade Name and Source
N,N'-di-sec-butyl Antioxidant AO-22, Octel-Starreon phenylene
diamine 2,6-di-t-butyl phenol + Antioxidant AO-37 (75%
2,6-di-t-butyl other phenols phenol, 25% other butylated phenols),
Octel- Starreon N,N'-bis-salicylidene- Metal Deactivator DMD (75%
active, in 1,2-propane diamine xylene), Octel-Starreon Xylene
solvent 2-Propanol solvent polyisobutylene amine detergent PURADD
AP-2000, BASF polyether amine detergent OGA-492, Oronite
polyisobutylene detergent DMA-548, Octel-Starreon diamine mixed
dimer acids corrosion inhibitor DCI-6A, Octel-Starreon dodecenyl
succinic corrosion inhibitor DDSA free acid (75% acid active, in
xylene) 2-(8-hepthldecenyl)-4, corrosion inhibitor Amine O, CIBA
5-dihydro-1H- imidazol- 1-ethanol Tolad 9308 (dehazer)
Dehazer/Demulsifier TOLAD 9308, Baker Petrolite
[0034]
4Table II Equivalent Compositions at 100% of Indicated Chemical
Species X- Fluid Material M2 #3 #4 #10 #11 #12 #13 #14 #15 #16
N,N'di-sec-butyl 7.3 6.8 6.8 6.8 6.8 6.8 6.8 3.4 3.4 4.1 phenylene
diamine 2,6-di-t-butyl 3.7 3.4 3.4 3.4 3.4 3.4 3.4 1.7 1.7 2 phenol
+ other phenols N,N'-bis- 9.8 6.825 6.825 6.825 6.825 1.2 0.675
salicylidene-1,2- propane diamine Xylene 44 37.875 29.675 59.4
52.575 55.4 48.575 64.5 60.3 53.725 2-Propanol 30 20 20
polyisobutylene r 2. amine polyisobutylene 22.2 30.3 30.3 30.3 30.3
30.3 30.3 30.3 36.4 diamine mixed dimer 1.6 1.6 4 4 acids dodecenyl
3 3 succinic acid 2-(8- 5.2 1.3 1.3 hepthldecenyl)- 4,5-dihydro-1H-
imidazole-1- ethanol Tolad 9308 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
(dehazer) TEST Mod. Nace.sup.1 E D B B+ A A IVD Test Time, 10 100
24 24 24 24 24 24 24 24 hr, Avg. IVD 141.25 918.75 137.75 15 50.8
23.8 45 11.5 30.2 10.25 100 hr IVD 1412.5 918.75 573.96 62.5 211.17
99.2 187.5 47.9 125.8 42.7 ASTM D525 >1440 >1440 >1440
Oxidation Stability .sup.1Modified NACE, National Association of
Corrosion Engineers 2. Detergent was added separately and not part
of package but was added in an amount such that the final package
contained 40 wt. %.
[0035] An inspection of Table II clearly shows that Comparative
Additives M2, 3 and 4 containing imidazole show markedly greater
intake-valve deposits than Additives 15 and 16 in accordance with
the present invention.
[0036] Comparative Additive 11 versus Comparative Additive 10 shows
that the presence of metal deactivator in a relatively great amount
has a deleterious effect on intake-valve deposits. Comparative
Additive 12 versus Comparative Additive 10 shows that the corrosion
inhibitor has a detrimental effect on intake-valve deposits while
improving the NACE corrosion valves.
[0037] Comparative Additive 12 versus Comparative Additive 13 shows
that the effect of metal deactivator is detrimental to intake-valve
deposits; however, both show improved NACE corrosion valves due to
the presence of the corrosion inhibitor.
[0038] Comparative Additive 14 versus Comparative Additive 10 shows
directionally improvement in intake-valve deposits when the amount
of antioxidant is reduced as required by the present invention.
[0039] Invention Additive 15 versus Comparative Addition 13 shows
improved intake-valve deposits by virtue of using a lower level of
metal deactivator, a lower level of antioxidants and a lower
molecular weight (i.e., lower carbon number) corrosion inhibitor in
accordance with the process of the invention.
[0040] Invention Additive 16 versus Comparative Additive 12 shows
the improved effect on intake-valve deposits by a lower molecular
weight corrosion inhibitor while including a lower level of metal
deactivator, which also provides good corrosion protection.
[0041] Finally, Invention Additives 15 and 16 show equivalent
oxidation results to Comparative Additive 10, despite the larger
amount of antioxidants present in Additive 10.
[0042] When the Invention Additive Package 16 as set forth in Table
II was used with a national generic certification fuel containing
10% ethanol and no ethanol, the 100 hr intake-valve deposits, avg.
mg. were 31.8 and 31 respectively. This showed that the additive in
accordance with the present invention afforded the beneficial
intake valve deposit results in a fuel containing ethanol.
* * * * *