Fuel and related compositions – Liquid fuels – Containing organic -c
Reexamination Certificate
2001-02-28
2002-11-05
Toomer, Cephia D. (Department: 1714)
Fuel and related compositions
Liquid fuels
Containing organic -c
C044S399000, C044S400000, C044S433000
Reexamination Certificate
active
06475251
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the use of fuel additive compositions containing aromatic esters of polyalkylphenoxyalkanols and poly(oxyalkylene) amines in direct injection spark ignition gasoline engines to prevent and control engine deposits.
2. Description of the Related Art
It is well known that automobile engines tend to form deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports and intake valves, due to the oxidation and polymerization of hydrocarbon fuel. These deposits, even when present in relatively minor amounts, often cause noticeable driveability problems, such as stalling and poor acceleration. Moreover, engine deposits can significantly increase an automobile's fuel consumption and production of exhaust pollutants.
Recently, direct injection spark ignition (DISI) engines have been introduced as an alternative to conventional port fuel injection spark ignition (PFI SI) engines. In the past few years, at least three types of DISI engines (from Mitsubishi, Toyota, and Nissan) have been commercially introduced into the Japanese market, and some models are now available in Europe and selected markets in Asia. Interest in these engines stems from benefits in the area of fuel efficiency and exhaust emissions. The direct injection strategy for spark ignition engines has allowed manufacturers to significantly decrease engine fuel consumption, while at the same time maintaining engine performance characteristics and levels of gaseous emissions. The fuel/air mixture in such engines is often lean and stratified (as opposed to stoichiometric and homogeneous in conventional PFI SI engines), thus resulting in improved fuel economy.
Although there are many differences between the two engine technologies, the fundamental difference remains fuel induction strategy. In a traditional PFI SI engine, fuel is injected inside the intake ports, coming in direct contact with the intake valves, while in DISI engines fuel is directly introduced inside the combustion chamber. Recent studies have shown that DISI engines are prone to deposit build-up and in some cases, these deposits are hard to remove using conventional deposit control fuel additives. Given that the DISI engine technology is relatively new, there is concern that with accumulated use, performance and fuel economy benefits may diminish as deposits form on various surfaces of these engines. Therefore, the development of effective fuel detergents or “deposit control” additives to prevent or reduce such deposits in DISI engines is of considerable importance.
The use of polyether amines, also known as poly(oxyalkylene)amines, to control fuel injector deposits in direct injection spark ignition gasoline engines has been described in S. Matsushita, “Development of Direct Injection S.I. Engine (D-4)”, Proceedings of JSAE (Japanese Society of Automotive Engineers), No. 9733440, March, 1997.
PCT International Application Publication No. WO 00/20537, published Apr. 13, 2000, discloses a gasoline additive for use in a direct injection gasoline engine which comprises at least one nitrogenous compound selected among polyoxyalkyleneamine compounds and polybutenylamine compounds.
U.S. Pat. No. 5,749,929, issued May 12, 1998 to Cherpeck et al., discloses a fuel additive composition comprising an aromatic ester of a polyalkylphenoxyalkanol and a poly(oxyalkylene) amine which is useful in fuel compositions for the control of engine deposits. However, this patent does not disclose the specific use of such additive compositions in direct injection spark ignition gasoline engines.
SUMMARY OF THE INVENTION
It has now been discovered that the combination of certain aromatic esters of polyalkylphenoxyalkanols with poly(oxyalkylene) amines affords a fuel additive composition which provides excellent control of engine deposits in direct injection spark ignition gasoline engines.
Accordingly, the present invention provides a method for controlling engine deposits in a direct injection spark ignition gasoline engine which comprises operating the engine with a fuel composition comprising a major amount of hydrocarbons boiling in the gasoline range and an effective deposit-controlling amount of a fuel additive composition comprising:
(a) an aromatic ester compound having the following formula or a fuel soluble salt thereof:
wherein R is hydroxy, nitro or —(CH
2
)
x
—NR
5
R
6
, wherein R
5
and R
6
are independently hydrogen or lower alkyl having 1 to 6 carbon atoms and x is 0 or 1;
R
1
is hydrogen, hydroxy, nitro or —NR
7
R
8
, wherein R
7
and R
6
are independently hydrogen or lower alkyl having 1 to 6 carbon atoms;
R
2
and R
3
are independently hydrogen or lower alkyl having 1 to 6 carbon atoms; and
R
4
is a polyalkyl group having an average molecular weight in the range of about 450 to 5,000; and
(b) a poly(oxyalkylene) amine having at least one basic nitrogen atom and a sufficient number of oxyalkylene units to render the poly(oxyalkylene) amine soluble in hydrocarbons boiling in the gasoline range.
The present invention further provides a method for controlling engine deposits in a direct injection spark ignition gasoline engine which comprises contacting the engine intake system with a fuel additive concentrate comprising an inert stable oleophilic organic solvent boiling in the range of from about 150° F. to about 700° F. and from about 5 to about 90 weight percent of the presently employed fuel additive composition described above.
In another aspect, the present invention relates to the use of the presently employed fuel composition described above for reducing engine deposits in a direct injection spark ignition gasoline engine. In a further aspect, the present invention also relates to the use of the presently employed fuel additive concentrate described above for reducing engine deposits in a direct injection spark ignition gasoline engine.
Among other factors, the present invention is based on the surprising discovery that the combination of certain aromatic esters of polyalkylphenoxyalkanols with poly(oxyalkylene) amines provides excellent control of engine deposits, especially in injectors and combustion chambers, particularly in the piston bowl or cavity, when employed in direct injection spark ignition gasoline engines.
As used herein, the term “deposit control”, or variations thereof, is meant to include the prevention, reduction or elimination of engine deposits.
DETAILED DESCRIPTION OF THE INVENTION
The Aromatic Ester of Polyalkylphenoxyalkanols
The aromatic ester component of the presently employed additive composition is an aromatic ester of a polyalkylphenoxyalkanol and has the following general formula:
or a fuel-soluble salt thereof, wherein R, R
1
, R
2
, R
3
and R
4
are as defined hereinabove.
Based on performance (e.g. deposit control), handling properties and performance/cost effectiveness, the preferred aromatic ester compounds employed in the present invention are those wherein R is nitro, amino, N-alkylamino, or —CH
2
NH
2
(aminomethyl). More preferably, R is a nitro, amino or —CH
2
NH
2
group. Most preferably, R is an amino or —CH
2
NH
2
group, especially amino. Preferably, R
1
is hydrogen, hydroxy, nitro or amino. More preferably, R
1
is hydrogen or hydroxy. Most preferably, R
1
is hydrogen. Preferably, R
4
is a polyalkyl group having an average molecular weight in the range of about 500 to 3,000, more preferably about 700 to 3,000, and most preferably about 900 to 2,500. Preferably, the compound has a combination of preferred substituents.
Preferably, one of R
2
and R
3
is hydrogen or lower alkyl of 1 to 4 carbon atoms, and the other is hydrogen. More preferably, one of R
2
and R
3
is hydrogen, methyl or ethyl, and the other is hydrogen. Most preferably, R
2
is hydrogen, methyl or ethyl, and R
3
is hydrogen.
When R and/or R
1
is an N-alkylamino group, the alkyl group of the N-alkylamino moiety preferably contains 1 to 4 carbon atoms. More preferably, the N-alkylamino is N-methylamin
Caroli Claude J.
Chevron Oronite Company LLC
Foley Joseph P.
Toomer Cephia D.
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