WO2003070861A2

WO2003070861A2 - Method for operating internal combustion engine with a fuel composition

Info

Publication number: WO2003070861A2
Application number: PCT/US2003/004722
Authority: WO
Inventors: Malcolm G.J. Macduff; Richard C. Chadwick; Mitchell M. Jackson
Original assignee: The Lubrizol Corporation
Priority date: 2002-02-19
Filing date: 2003-02-18
Publication date: 2003-08-28
Also published as: AU2003213093A1; WO2003070861A3; US20050172544A1; EP1478717A2

Abstract

A method for preventing combustion chamber deposits from causing start-failures in an internal combustion engine comprises operating the engine with a fuel composition that contains a normally liquid fuel and a nitrogen-containing detergent that includes a polyetheramine; a Mannich reaction product of a hydrocarbyl-substituted phenol, an aldehyde and an amine; or a mixture there. The method is effective in preventing start-failures in multi-valve, low friction, spark-ignited engines.

Description

TITLE: METHOD FOR OPERATING INTERNAL COMBUSTION ENGINE WITH A FUEL COMPOSITION

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

This invention relates to a methodology to overcome field problems that can prevent motor vehicles having high performance, multi-valve, low friction, internal combustion engines from restarting after short-distance, low speed driving conditions. The methodology comprises operating the engine with a fuel composition containing a fuel additive. The methodology further comprises optionally running the engine in a clean-up cycle with the fuel composition containing an aftermarket treatment level of the fuel additive before returning to normal service. DESCRIPTION OF THE RELATED ART

In recent years, engine manufacturers have been putting greater emphasis on increasing the fuel economy and efficiency of their engines in order to meet the demanding global fuel economy standards such as the Federal Corporate Average Fuel Economy (CAFE) standards in the United States. While significant improvements to fuel economy have been made by new engine designs, some aspects of these new engine designs are leading to new problems not observed before that occur under certain driving conditions. A problem mainly affecting certain high performance, multi-valve, low friction, spark-ignited engines such as the M52 6- cylinder in-line BMW engine occurs when driving conditions are almost exclusively of the short-distance, low speed type. The valves in a low friction engine have springs that require less compressive force to open the valves. Engines driven under short-distance, low speed conditions for a period of time tend to build up deposits in the combustion chamber. When a low friction engine with such accumulated combustion chamber deposits is switched off for several hours, condensation of water, gasoline or both can soak the deposits and loosen them from the engine parts. Upon subsequent use of the engine for another short period of time, the loosened deposits can dislodge as flakes and become trapped between the valve and the valve seat. The net result of these trapped deposits is that they can prevent or make difficult restarting the engine due to the inability of the engine to build up compression.

As is well known, hydrocarbon fuels, including gasoline and diesel fuel, generally contain numerous deposit-forming substances that tend to form deposits in the fuel system of an internal combustion engine on and around intake valves, fuel injectors and combustion chambers. These deposits can adversely effect the performance of the engine in the areas of driveability seen in terms of stalling and acceleration, fuel economy, and exhaust emissions of regulated substances such as hydrocarbons, nitrogen oxides and carbon monoxide. A variety of fuel additives or deposit control additives to prevent or control such deposits are known in the art.

Hydrocarbyl-substituted amines and succinimides having the hydrocarbyl group derived from polybutene are well known in the art as fuel additives that aid in decreasing deposits in intake valves and port fuel injectors of internal combustion engines. However, they have been considered to contribute to, rather then prevent, combustion chamber deposits at dose rates (50-1,000 ppm) typically used to control intake valve deposits. U.S. Patent No. 6,136,051 teaches that relative to a base fuel without deposit control additives that low dosages of hydrocarbyl-substituted amines increase combustion chamber deposits (CCD) and that higher dosages (>1,200 ppm) of the amines give better CCD control. Polyetheramine fuel additives are also well known in the art for the prevention and control of engine deposits. For example, U.S. Patent No. 4,191,537 discloses a fuel composition comprising a major portion of hydrocarbons boiling in the gasoline range and from 30 to 2,000 ppm of a hydrocarbyl polyoxyalkylene aminocarbamate having a molecular weight from about 600 to 10,000 and at least one basic nitrogen > atom. These fuel compositions are taught to maintain the cleanliness of intake systems without contributing to combustion chamber deposits.

U.S. Patent No. 6,217,624 teaches, as with hydrocarbyl-substituted amines in U.S. Patent No. 6,136,051 above, that polyetheramines at low dosages of 300 ppm also contribute to combustion chamber deposits even though intake valve deposits are prevented while at higher dosages (>2,050 ppm) both intake valve and combustion chamber deposits can be prevented. U. S. Patent No. 5,407,453 teaches the use of a composition comprising an alkoxy alcohol, an aliphatic alcohol, a petroleum distillate, a fatty acid, a nitrogen base, a hydrocarbyl amine, and water can be used to clean up combustion chamber deposits formed in an internal combustion engine. Mechanical means such as running an engine at high speeds under full load conditions are also know to clear engine of all deposits. Mechanical methods of removing engine deposits are well known to those skilled in the art.

None of the chemical and mechanical methods listed above provides a practical solution to the problem of combustion chamber deposit buildup and subsequent engine start-failures in a high performance, multi-valve, low friction, spark-ignited engine. The chemical methods are economically too costly due to the required high dosages. The mechanical methods do not prevent the problem from recurring.

A method has now been discovered that is both economical and effective in preventing recurrence of the problem of engine start-failures due to combustion chamber deposit buildup in an internal combustion engine to include a high performance, multi-valve, low friction, spark-ignited engine. The method comprises operating an internal combustion engine with a fuel composition that contains certain nitrogen-containing detergents. SUMMARY OF THE INVENTION

It is an object of the present invention to control combustion chamber deposits in an internal combustion engine.

Another object of the present invention is to prevent problems related to engine restart in an internal combustion engine. A further object of the present invention is to control combustion chamber deposits in a multi-valve, low friction, spark-ignited engine.

A still further object of the present invention is to prevent problems related to engine restart in a multi-valve, low friction, spark-ignited engine.

The objects, advantages and embodiments of the present invention are in part described in this application and in part are obvious from the application or from the practice of this invention. Therefore, it is understood that the invention is claimed as described or obvious as falls within the scope of the appended claims. To achieve the foregoing objects in accordance with the invention as described and claimed herein, a method of this invention for preventing combustion chamber deposits from causing start-failures in an internal combustion engine comprises operating the engine with a fuel composition comprising a normally liquid fuel; and a nitrogen-containing detergent comprising a polyetheramine; a Mannich reaction product of a hydrocarbyl-substituted phenol, an aldehyde, and an amine; or a mixture thereof.

In another embodiment of the present invention, the internal combustion engine of the above described method is a multi-valve, low friction, spark-ignited engine; and the fuel is a gasoline.

In a further embodiment of this invention, the polyetheramine of the above described method is represented by the formula RO(AO)_mR¹NR²R³ wherein R is a hydrocarbyl group of about 8 to about 30 carbon atoms; A is an alkylene group having 2 to 6 carbon atoms; m is a number from 1 to about 50; R¹ is an alkylene group having 2 to 6 carbon atoms; and R² and R³ are independently hydrogen, a hydrocarbyl group or -[R⁴N(R⁵)]_nR6 wherein R⁴ is an alkylene group having 2 to 6 carbon atoms, R⁵ and R are independently hydrogen or a hydrocarbyl group, and n is a number from 1 to 7.

In an additional embodiment of the present invention, the fuel composition of the above described method is prepared by adding the nitrogen-containing detergent as a bulk treatment to the fuel wherein the amount of the detergent in the fuel composition is 100 to 1,000 ppm by weight.

In yet another embodiment of this invention, the fuel composition of the above described method is prepared by adding the nitrogen-containing detergent as an aftermarket treatment to the fuel wherein the amount of the detergent in the fuel composition is 1,000 to 10,000 ppm by weight.

In still a further embodiment of the present invention, the engine is operated with the aftermarket treated fuel composition under a clean-up cycle wherein the cycle generates engine speeds of at least 3,000 rpm. DETAILED DESCRIPTION OF THE INVENTION

A method of the present invention for preventing combustion chamber deposits from causing start-failures, as was described above in the Description of the Related Art section for this problem, in an internal combustion engine comprises operating the engine with a fuel composition comprising a normally liquid fuel; and a nitrogen-containing detergent comprising a polyetheramine; a Mannich reaction product of a hydrocarbyl-substituted phenol, an aldehyde, and an amine; or a mixture ^~ thereof.

Polyetheramines of this invention include compounds having two or more consecutive ether groups and at least one primary, secondary or tertiary amine group where the amine nitrogen has some basicity. The polyetheramines of this invention include poly(oxyalkylene) amines having a sufficient number of repeating oxyalkylene units to render the poly(oxyalkylene)amine soluble in a normally liquid fuel such as in hydrocarbons boiling in a gasoline or diesel fuel range. Generally poly(oxyalkylene)amines having at least about 5 oxyalkylene units are suitable for use in the present invention. Poly(oxyalkylene)amines can include hydrocarbylpoly(oxyalkylene)amines, hydrocarbylpoly(oxyalkylene)polyamines, hydropoly(oxyalkylene)amines, hydropoly(oxyalkylene)polyamines, and derivatives of polyhydric alcohols having at least two poly(oxyalkylene)amine and/or poly(oxyalkylene)polyamine chains on the molecule of the derivative. Throughout this application a hydrocarbyl group is a univalent group of one or more carbon atoms that is predominately hydrocarbon in nature, but can contain heteroatoms such as oxygen in the carbon chain and can have nonhydrocarbon or heteroatom-containing groups such as hydroxy, halo, nitro and alkoxy attached to the carbon chain. A preferred poly(oxyalkylene)amine for use in the invention is represented by the formula RO(AO)_mR¹NR²R³ (I) wherein R is a hydrocarbyl group of 1 to 50 carbon atoms and preferably of about 8 to about 30 carbon atoms; A is an alkylene group having 2 to 18 carbon atoms and preferably 2 to 6 carbon atoms; m is a number from 1 to about 50; R¹ is an alkylene group having 2 to 18 carbon atoms and preferably 2 to 6 carbon atoms; and R and R are independently hydrogen, a hydrocarbyl group or -[R⁴N(R⁵)]_nR⁶ wherein R⁴ is an alkylene group having 2 to 6 carbon atoms, R⁵ and R⁶ are independently hydrogen or a hydrocarbyl group, and n is a number from 1 to 7. Another preferred poly(oxyalkylene)amine of the present invention is represented by the formula RO[CH₂CH(CH₃CH₂)O]_mCH₂CH₂CH₂NH₂ (H) wherein R is an aliphatic group or alkyl-substituted phenyl group of about 8 to about 30 carbon atoms; and m is a number from about 12 to about 30. Also preferred is a poly(oxyalkylene)amine represented by the formula CH₃CH(CH₃)[CH₂CH(CH₃)]₂CH(CH₃)CH₂CH₂O- [CH₂CH(CH₃CH₂)O]_mCH₂CH₂CH₂NH₂ (III) wherein m is a number from about 16 to about 28. Poly(oxyalkylene)amines of the present invention can have a molecular weight in the range from about 300 to about 5,000.

The polyetheramines of the present invention can be prepared by initially condensing an alcohol or alkylphenol with an alkylene oxide, mixture of alkylene oxides or with several alkylene oxides in sequential fashion in a 1: 1-50 mole ratio of hydric compound to alkylene oxide to form a polyether intermediate. U.S. Patent Nos. 5,112,364 and 5,264,006 provide reaction conditions for preparing a polyether intermediate.

The alcohols can be monohydric or polyhydric, linear or branched, saturated or unsaturated and having 1 to 50 carbon atoms, preferably from 8 to 30 carbon atoms, more preferably from 10 to 16 carbon atoms. Branched alcohols of the present invention can include Guerbet alcohols, as described in U.S. Patent No. 5,264,006, which generally contain between 12 and 40 carbon atoms and can be represented by the formula RCH(CH₂CH₂R)CH₂OH (IV) where R is a hydrocarbyl group. The alkyl group of the alkylphenols can be 1 to 50 carbon atoms, preferably 2 to 24 carbon atoms, and more preferably 10 to 20 carbon atoms. The alkylene oxides include 1 ,2-epoxyalkanes having 2 to about 18 carbon atoms, preferably having 2 to about 6 carbon atoms, and more preferably are ethylene oxide, propylene oxide and butylene oxide. Especially useful is propylene oxide, butylene oxide, or a mixture thereof. The number of alkylene oxide units in the polyether intermediate is 1-50, preferably 12-30, and more preferably 16-28. The polyether intermediates can be converted to polyetheramines by several methods. The polyether intermediate can be converted to a polyetheramine by a reductive amination with ammonia, a primary amine or a polyamine as described in U.S. Patent Nos. 5,112,364 and 5,752,991. In a preferred method, the polyether intermediate can be converted to a polyetheramine via an addition reaction of the polyether to acrylonitrile to form a nitrile which is then hydrogenated to form the polyetheramine. U.S. Patent No. 5,264,006 provides reaction conditions for the cyanoethylation of the polyether with acrylonitrile and the subsequent hydrogenation to form the polyetheramine. In another method, the polyether intermediate or poly(oxyalkylene) alcohol is converted to the corresponding poly(oxyalkylene) chloride via a suitable chlorinating agent followed by displacement of chlorine with ammonia, a primary or secondary amine, or a polyamine as described in U.S. Patent No. 4,247,301.

The nitrogen-containing detergent of the present invention can be a Mannich reaction product from the reaction of a hydrocarbyl-substituted phenol, an aldehyde, and an amine. The hydrocarbyl substituent can be derived from a polyolefin having a number average molecular weight of 450 to 3,000, in a second instance of 500 to 2300, and in a third instance of 550 to 1,500. The polyolefin can be a homopolymer from a single olefin monomer, a copolymer from a mixture of two or more olefin monomers, or a mixture thereof. Useful olefin monomers include C₂ through ₂ alkenes such as ethylene, propylene, butenes including isobutylene, and 1-decene and dienes such as isoprene and 1,3-butadiene. The polyolefin can be a polyisobutylene, and in another instance can be a polyisobutylene containing a major amount of its double bonds as vinylidene bonds. The polyisobutylene can have a vinylidene bond content of 5 to 69%, or 50 to 69%, or 50 to 95%. The hydrocarbyl-substituted phenol can be prepared by well known methods for phenol alkylation. In another embodiment of the invention the hydrocarbyl-substituted phenol can contain an additional substituent which can be an alkyl group. The alkyl group can contain about 1 to 10 carbon atoms. The hydrocarbyl-substituted, alkyl-substituted phenol can be derived from cresols such as ortho-cresol. The aldehyde can be formaldehyde or a reactive equivalent thereof. The amine can be ammonia, a monoamine or a polyamine and includes alkanolamines. Useful amines include ethanolamine, di- ethanolamine, methylamine, dimethylamine, 2-(2-aminoethylamino)ethanol, ethylene- diamine, dimethylaminopropylamine, and diethylenetriamine. In an embodiment of the invention the Mannich reaction product is prepared from an alkylphenol derived from a polyisobutylene, formaldehyde, and an amine that is an alkylenediamine or a dialkylamine. In a further embodiment the alkylenediamine is ethylenediamine. In a still further embodiment the dialkylamine is dimethylamine. Mannich reaction products can be prepared by well known methods including the methods described in U.S. Patent Nos. 5,697,988 and 5,876,468. The nitrogen-containing detergent of the present invention can be a mixture of two or more polyetheramines, of two or more Mannich reaction products, or of one or more polyetheramines and one or more Mannich reaction products.

The normally liquid fuel of the present invention may be a hydrocarbon aceo us petroleum distillate fuel boiling in the gasoline or diesel fuel range. Normally liquid fuels comprising non-hydrocarbonaceous materials, such as alcohols, ethers and organo-nitro compounds including methanol, ethanol, diethyl ether, methyl ethyl ether, methyl t-butyl ether and nitromethane, are also within the scope of this invention as are materials derived from vegetable or mineral sources such as corn, alfalfa, shale and coal. Normally liquid fuels which are mixtures of one or more hydrocarbonaceous fuels and one or more non-hydrocarbonaceous materials are also within the scope of the invention and include mixtures of gasoline with ethanol and of gasoline with methyl t-butyl ether. In a preferred embodiment, the normally liquid fuel is a gasoline as defined by ASTM specification D4814 or EN228 specifications having a distillation range from about 60°C at the 10% distillation point to about 205°C at the 90% distillation point. In one embodiment, the gasoline is a chlorine- free or low-chlorine gasoline characterized by chlorine content of no more than about 10 ppm by weight. In another embodiment, the gasoline is a low-sulfur gasoline characterized by a sulfur content of no more than about 80 ppm by weight. In other instances the low-sulfur gasoline has a sulfur content below 50, 15, or 10 ppm by weight. The gasoline can contain lead or be essentially free of lead.

In an embodiment of the method of the present invention the internal combustion engine is a multi-valve, low friction, spark-ignited engine; and the fuel is a gasoline. As described above in the Background of The Invention section, this type of engine is generally a high performance engine that can experience start-failures when operated mainly or almost exclusively under short-distance, low speed conditions where the low friction in the engine is due to the engine having valves with springs that require less compressive force to open the valves.

The fuel composition of the present invention can contain, in addition to the nitrogen-containing detergent, one or more additional additives. These include antioxidants such as 2,6-di-t-butylphenol and 2,6-di-t-butyl-4-methylphenol, metal deactivators such as N,N'-bis(salicylidene)-l,2-propanediamine, conventional ashless dispersants, thermal stability additives, antiknock agents such as tetraalkyl lead compounds, lead scavengers such as halogen-containing alkanes, deposit preventers or modifiers such as triaryl phosphates, dyes, octane improvers or cetane improvers, corrosion inhibitors such as alkylated succinic acids and anhydrides and reaction products of alkenylsuccinic anhydrides and alkanolamines, anti-valve seat recession additives such as alkali metal sulphosuccinate salts, antistatic agents, lubricity additives to include esters of fatty carboxylic acids such as glycerol mono- and dioleates and alkoxylated fatty amines such as diethoxylated tallowamine, fluidizers to include polyethers and polyolefins and mineral oils, bacteriostatic agents, gum inhibitors, demulsifiers, upper cylinder lubricants, and antiicing agents. Ashless dispersants can include a reaction product of a hydrocarbyl-substituted acylating agent and an amine such as the reaction product of a polyisobutenylsuccinic acylating agent and a polyamine as disclosed in U.S. Patent No. 5,719,108 and can also include a hydrocarbyl-substituted amine prepared by several methods as disclosed in U.S. Patent No. 6,193,767 including halogenating a polyolefin followed by reacting the halogenated polyolefin with a polyamine as disclosed in U.S. Patent No. 5,407,453. Thermal stability additives can include an oligomeric reaction product from reacting together in a solvent in the presence of a basic catalyst dodecylphenol, salicylic acid and formaldehyde as disclosed in U.S. Patent No. 6,200,936. The fluidizer can be a polyether to include polyethers prepared by reacting an alcohol or alkylphenol, where the alcohol or alkyl group of the phenol has 1 to 50 carbon atoms or 8 to 30 carbon atoms, and 5 to 50 units of an alkylene oxide. In another instance the number of units of alkylene oxide reacted with the alcohol or alkylphenol is about 15 to 30. Alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, or mixtures thereof. Especially useful alkylene oxides are propylene oxide, butylene oxide, or mixtures thereof. The polyether can be prepared as described in U. S. Patent No. 5,094,677.

The nitrogen-containing detergent, to include the polyetheramine and the Mannich reaction product, and any additional additive or additives of the present invention can be added to the fuel as a concentrate. The concentrate can contain one or more nitrogen-containing detergents such as a polyetheramine at 100% actives. The concentrate can also contain inert, stable organic solvents generally boiling in the range of about 65-205°C. Preferably, an aliphatic or an aromatic hydrocarbon solvent can be used such as benzene, toluene, xylene or higher-boiling aromatics or aromatic thinners. Aliphatic alcohols of about 3 to 8 carbon atoms, such as isopropanol, n- butanol and isobutylcarbinol, are also suitable for use as solvents alone or in combination with the hydrocarbon solvents. In the concentrate the amount of the nitrogen-containing detergent and any additional additives will be ordinarily be least 10 percent to 100 percent by weight.

Generally, the fuel composition of the present invention contains an effective amount of the nitrogen-containing detergent to enhance the detergency of the fuel composition and thus to stop or prevent combustion chamber deposits from causing engine start-failures in an internal combustion engine such as a multi-valve, low friction, spark-ignited engine. In one embodiment of the invention the fuel composition is prepared by adding the nitrogen-containing detergent as a bulk treatment to the fuel wherein the amount of the detergent in the fuel composition is 100 to 1,000 ppm by weight. In other instances of the invention the amount of the detergent in the fuel composition from the bulk treatment is 100 to 200, 100 to 300, 100 to 400, 100 to 500, 200 to 900, 300 to 800, and 300 to 500 ppm by weight. In the bulk treatment the detergent is added to the fuel at a fuel terminal or fleet site to form the fuel composition prior to adding the fuel composition to a fuel tank of a motor vehicle powered by the internal combustion engine. In another embodiment of the invention the fuel composition is prepared by adding the nitrogen-containing detergent as an aftermarket treatment to the fuel wherein the amount of the detergent in the fuel composition is 1,000 to 10,000 ppm by weight. In other instances of the invention the amount of the detergent in the fuel composition from the aftermarket treatment is 1000 to 2000, 1000 to 3000, 1000 to 4000, 1000 to 5000, 2000 to 9000, 2000 to 4000, and 3000 to 8000 ppm by weight. In the aftermarket treatment the detergent can be added to the fuel in a fuel tank of a motor vehicle powered by the internal combustion engine. In an embodiment of the invention the detergent added to the fuel in the aftermarket treatment is the polyetheramine, and in another embodiment of the invention the detergent added to the fuel in the aftermarket treatment is the Mannich reaction product. In an embodiment of the invention an engine, which has accumulated combustion chamber deposits to a point where there are restart problems, can be operated with the fuel composition containing an aftermarket treatment of the detergent under normal service. In another embodiment of the invention an engine, that has accumulated combustion chamber deposits to a point where there are restart problems, can be operated with the fuel composition containing an aftermarket treatment of the detergent under a short clean-up cycle which generates speeds of at least 3,000 rpm and preferably of at least 3,500 rpm. Any service or clean-up cycle, however, can be used effectively in which the engine is operated with the fuel composition at engine speeds of at least 3,000 rpm and preferably of at least 3,500 rpm for more than 20 seconds for 2-8 repetitions or cycles. Operating an internal combustion engine with a fuel composition of the present invention prepared by a bulk or aftermarket treatment as described above prevents combustion chamber deposits from causing start-failures in the engine. The bulk treatment method can be used as a preventive measure for engine restart problems while the aftermarket treatment method can be used as a curative measure after engine restart problems have occurred. The following examples for preparing a polyetheramine and of engine test evaluations using that polyetheramine and several Mannich reaction products demonstrate the effectiveness of the present invention in preventing combustion chamber deposits from causing engine start-failures. These examples are provided for illustrative puiposes only and are not intended to limit the scope of the invention. Example A

Part A

Tridecyl alcohol (4.00 lbs, 1814.4 g; 9.07 moles) is charged to a five-gallon nitrogen filled autoclave. Agitation is commenced. An aqueous solution of potassium hydroxide (0.30 lb, 134.7 g, 45 wt% KOH in water) is added. The reactor is purged with purified nitrogen and heated to 126.7°C while applying vacuum to strip water. At 126.7°C vacuum stripping is conducted for 0.5 hr to 0.13 atmosphere final pressure. The vacuum is relieved with nitrogen. Butylene oxide (29.01bs, 13.16 kg, 182.75 moles) is added over 6-10 hour time period at a rate such that the reactor temperature does not drop below 121 °C or exceed 132°C and the reactor's pressure does not exceed 80 psi (in Example A pressures given in psi units are gauge values). After the butylene oxide addition is complete, the temperature is maintained at 126.7°C for 2 hours. The reactor's pressure is allowed to equilibrate and decrease to less than 10 psi. The reactor pressure is vented slowly to zero psi. The product mixture is cooled to 82°C while it is vacuum stripped. The vacuum is relieved with nitrogen. Solid magnesium silicate (1.2 lbs) is added to neutralize the reaction product. The product mixture is stirred for one hour. The product is cooled to 49- 60°C. The reaction product is filtered until its residual potassium level is 10 ppm or less. The product has a hydroxyl number (ASTM E326-96) of 34.5, a viscosity at 100°C (ASTM D445) of 21.3 cSt, and a specific gravity (ASTM D4052) of 0.9614 g/cc. Part B

Product from Part A (3.8 moles) is introduced to a 5-liter 4-necked round bottom flask equipped with a thermometer, overhead stirrer, condenser, and a dropping funnel. A few drops of a solution of 45 wt % KOH in water are added to catalyze the reaction. The contents of the flask are heated to 30°C with stirring. Acrylonitrile (271.3 g, 5.1 mol) is charged to the dropping funnel, and approximately 50 ml aliquots of acrylonitrile are added over a couple of minutes per aliquot and at about 15 to 20 minute intervals between aliquots in such a manner that maintains the temperature at less than 40°C. After adding 247 g of the acrylonitrile, an additional 4 g of the solution of 45 wt % KOH in water are added. The last 24.3 g of acrylonitrile are then added while monitoring the nitrile and hydroxyl functionality by infrared spectroscopy. The mixture is stirred an additional 1 hour until the infrared spectrum shows no further conversion of hydroxyl functionality. Approximately 70% of the hydroxyl groups are reacted according to the infrared analysis. Water (10 ml) is added. The mixture is allowed to sit an hour at 40°C and the water settles. Hydrochloric acid (0.5 N) is then added dropwise with stirring until the pH of the reaction mixture is neutral. The neutralized solution is filtered to remove any acrylonitrile polymer and inorganic salts. The product (3,200 g) is an amber colored filtrate of ether nitrile. Part C

Raney Nickel catalyst (40 g, 1.3 wt %, based on ether nitrile) is washed 3 times with 500 ml aliquots of isopropanol. In the first two washings, the solvent is decanted off and fresh solvent added. After suspending the catalyst in the third aliquot of isopropanol, the suspended catalyst is added to a two-gallon autoclave reactor. The ether nitrile prepared in Part B above (3200 g, 3.5 moles) is then added to the reactor, and the reactor contents are stirred. A vacuum of 0.84 atmosphere pressure is applied to the system, and the contents of the reactor are heated to 120°C. The isopropanol and any residual water is removed by distillation over two hours until no condensate is seen forming on the condenser. The reactor is sealed. Hydrogen is then added to a pressure of 10 psi and the reactor is vented. The hydrogen purge and venting are repeated. Hydrogen is again added to a pressure of 10 psi and the contents of the reactor cooled over a few minutes to 70°C. The temperature of the reactor contents is increased to 135°C (pressure increases to 160 psig) over approximately 30 minutes. Hydrogen is added to maintain the pressure at 320 psi and the temperature is maintained at 135°C to 140°C for 32 hours. The reactor contents are cooled to 120 °C, vented, and a vacuum of 0.84 atmosphere pressure is applied. The reactor contents are vacuum distilled for two hours, cooled to 50 °C, and then drained from the reactor and filtered. The product (2950 grams) is tridecyloxy(butoxy)_x-n-propyleneamine wherein x is a number in the range of 12 to 30 with about 85 to 90 % of x being in the range of 18 to 22. The product has a nitrogen content of 0.71 % by weight and a total base number of 28.5.

In order to show the ability of the method of the present invention, which uses a nitrogen-containing detergent that includes a polyetheramine or a Mannich reaction product or a mixture thereof, to prevent combustion chamber deposits from causing engine start-failures, combustion chamber deposits were intentionally accumulated in an engine per a deposit buildup cycle as detailed in Table 2. The engine, with a buildup of deposits, was then run on 70 liters (one tank full) of standard gasoline dosed with 3,000 ppm of the polyetheramine of Example A using a clean-up cycle as detailed in Table 3. The engine test evaluation results are set forth in Table 1. Table 4 details a second deposit buildup cycle, greatly reduced in duration, which was developed. Table 5 contains results of engine restart evaluations for several additive types using both deposit buildup cycles or tests and both bulk and aftermarket treatments of the fuel.

tester, model 0 681 001 901.

The high speed clean-up consisted of running the engine, a M52 6-cylinder in-line BMW gasoline engine, for 20 minutes at 6000 rpm under a full load with a standard gasoline containing conventional additives. Fuel used during deposit buildup cycle was a standard gasoline containing conventional additives, and deposit buildup cycle was run per the procedure of Table 2.

⁴Gasoline, 70 liters, contained 3,000 ppm by mass of polyetheramine of Example A and conventional additives; clean-up cycle per procedure of Table 3 was run. ⁵Deposit buildup cycle used the procedure of Table 2 and the remainder of the 70 liters of gasoline containing Example A and conventional additives before switching back to standard gasoline containing conventional additives.

⁶Gasoline contained 3,000 ppm by mass of polyetheramine of Example A, and cleanup procedure of Table 3 was run. As the data in Table 1 indicates, following mechanical removal in a high speed clean-up of engine deposits such as combustion chamber deposits, combustion chamber deposits will re-form when a modern, high performance, multi-valve, low friction engine such as the BMW M52 6-cylinder in-line gasoline engine is run through a deposit buildup cycle or test procedure mimicldng short-distance, low speed driving. The buildup of these combustion chamber deposits ultimately leads to loss of cylinder compression and can result in an engine start-failure, that is, the engine fails to restart or starts with difficulty. Subsequent running of this engine in a clean-up cycle or test on one tank full of fuel dosed with 3,000 ppm of a polyetheramine additive such as the polyetheramine of Example A returns the cylinder compression loss back to normal values (9-11%) and eliminates engine start-failures. Surprisingly, the data in Table I further illustrates that the clean-up cycle or test provides prolonged restart benefits that go beyond the benefits of a mechanical high speed clean-up. As seen in the data, even though compression loss is observed in the engine start test that follows the second deposit buildup cycle that in turn follows a clean-up test or cycle that used the polyetheramine of Example A, there is no restart failure associated with the compression loss.

625 Hour Deposit Buildup Test A M52 6-cylinder in-line BMW gasoline engine was cleared of engine deposits in a high speed clean-up cycle by running at 6000 rpm under a full load for 20 minutes. Following this mechanical clean-up procedure, the engine was run on a standard fuel containing conventional additives for preventing intake valve deposits in a 625 hour deposit buildup procedure or test consisting of a 75 minute cycle repeated 500 times. Each cycle consisted of 15 minutes of a running cycle detailed in Table 2 and 60 minutes with the engine switched off to approximate short distance, low-speed driving. This procedure accelerates the buildup of combustion chamber deposits. Table 2 Engine Running Cycle for 625 Hour Deposit Buildup Test.

Engine Start-Failure Sequence for Engine Start Test After the buildup cycle, the engine is switched off for 24 hours. Following this

24 hour period the engine is started, the throttle or accelerator pedal is advanced twice, to raise the engine speed to nominally 2000 rpm, for two short engine revs and then returned to idle, and the engine is switched off immediately and allowed to sit for

24 hours. Following this 24 hour period, starting the engine is attempted. If engine starts, the engine is immediately switched off and left for 24 hours. The engine starting procedure followed by the 24 hour off period is continued until the engine does not start within 10 seconds of the starter motor being activated or a test pass is obtained. A test pass is obtained when the engine successfully starts on three successive attempts following the engine start in which the throttle was advanced twice. A test failure is registered when the engine fails to start within a 10 second period on any attempt to start the engine.

Engine Clean-up Cycle

After a tank of fuel of a vehicle has been dosed with an aftermarket treatment level of a nitrogen-containing detergent of the present invention such as the polyetheramine of Example A, the vehicle can be returned to normal service or preferably the vehicle can be driven over a short clean-up cycle to remove a buildup of combustion chamber deposits. A specific clean-up cycle that can be used is detailed in Table 3. The clean-up cycle is broken down into three cycles. Cycle 1 is

100 seconds in duration and is run twice; Cycle 2 is 170 seconds in duration and is run four times; Cycle 3 is 100 seconds in duration and is run twice, Overall, the total time for the clean-up cycle is 18 minutes.

Table 3 Engine Clean-u Cycle,

60 Hour Deposit Buildup Test A shortened version of the 625 hour deposit buildup was developed to reduce the cost and time of testing for engine start-failures due to combustion chamber deposits. The engine was cleared of deposits by running it in a high speed mechanical clean-up at 6,000 rpm under full load for 20 minutes. Following this mechanical clean-up the engine was run on a standard fuel, normally containing additives, in a 60 hour deposit buildup test. The 60 hour deposit buildup test consisted of a 4.5 minute engine cycle detailed in Table 4 that was repeated 800 times. This cycle is the same cycle that is used in the CEC M102E Inlet Valve Deposit Test (CEC F-05-A-93). The 60 hour deposit buildup test consumes about 250 liters of fuel which is similar to the amount of fuel consumed in the 625 hour deposit buildup test.

Table 4 Engine Cycle for 60 Hour Deposit Buildup Test

Detailed in Table 5 are engine restart evaluations that were run on several additive types using both bulk and aftermarket treatments of the fuel and both the 60 hour and 625 hour deposit buildup tests. The two deposit buildup tests appear to be in agreement on indicating the engine restart performance provided by the additives. Examples 1-4 indicate that an untreated fuel or a fuel treated with a conventional additive does not prevent engine start-failures. Examples 5-12 are embodiments of the invention which prevent engine start-failures. Although Example 5 gave a fail result, it was on the third attempt in the engine start-failure sequence after two successful attempts so the fail can be viewed as a marginal fail. Table 5

Engine Restart Evaluations¹ Based on Additive, Additive Treatment and Deposit

Buildup Test

Engine restart evaluations were done on a 6-cylinder, 4 valves per cylinder, multipoint injection gasoline engine typical of an engine that had demonstrated combustion chamber deposit related engine start-failure in the field. The base fuel was either a major European commercial fuel or a CEC test reference fuel. The evaluation procedure for Examples 1-10 consisted of a) a high speed mechanical clean-up by running the engine at 6000 rpm and full load for 20 minutes, b) the 625 or 60 hour deposit buildup as described hereinabove, and c) the engine start-failure sequence as described above. The evaluation procedure for Examples 11-12 consisted of a) the high speed mechanical clean-up, b) the 625 or 60 hour deposit buildup, c) the engine clean-up cycle described above, and d) the engine start-failure sequence. ²In Example 1 the base fuel was used without an additive throughout the entire evaluation procedure. In Examples 2-10 the base fuel contained a bulk treatment level (about 100-1,000 ppm) of the additive throughout the entire evaluation procedure. In Examples 11-12 the base fuel contained a bulk treatment level of additive A throughout the entire evaluation procedure and contained an aftermarket treatment level (about 1,000 to 10,000 ppm) of additive C during the engine clean-up cycle.

³Fail results include the point in the engine start-failure sequence at which the engine failed to start within 10 seconds. Addive A consisted of conventional additives for gasoline at a bulk treatment level. ⁵Additive Bi consisted of a) a Mannich reaction product at 135 ppm by mass from 1000 molecular weight polyisobutylene (PIB) alkylated ortho-cresol, formaldehyde and ethylenediamine, b) a polyether fluidizer, c) a corrosion inhibitor and d) a demulsifier. ⁶ Additive B₂ consisted of a) a Mannich reaction product at 176 ppm by mass from 1000 mol. wt. PIB alkylated phenol, formaldehyde and ethylenediamine, b) a polyether fluidizer, c) a corrosion inhibitor, and d) a demulsifier. ⁷Additive B₃ consisted of a) a Mannich reaction product at 168 ppm by mass from 1000 mol. wt. PLB alkylated phenol, formaldehyde and dimethylamine, b) a polyether fluidizer, c) a corrosion inhibitor, and d) a demulsifier.

⁸Additive C was the polyetheramine of Example A described hereinabove at 400 ppm by mass.

⁹ Additive A consisted of conventional additives for gasoline at a bulk treatment level; Additive C was the polyetheramine of Example A at an aftermarket treatment level of 3000 ppm by mass. Each of the documents referred to in this Detailed Description of the Invention section is incorporated herein by reference. All numerical quantities in this application used to describe or claim the present invention are understood to be modified by the word "about" except for the examples or where explicitly indicated otherwise. All chemical treatments or contents throughout this application regarding the present invention are understood to be as actives unless indicated otherwise even though solvents or diluents may be present.

Claims

What is claimed is:

1. A method for preventing combustion chamber deposits from causing start- failures in an internal combustion engine, comprising: operating the engine with a fuel composition comprising a normally liquid fuel; and a nitrogen-containing detergent comprising a polyetheramine; a Mannich reaction product of a hydrocarbyl-substituted phenol, an aldehyde, and an amine; or a mixture thereof.

2. The method of claim 1 wherein the fuel composition comprises the normally liquid fuel; and a polyetheramine.

3. The method of claim 1 wherein the internal combustion engine is a multi- valve, low friction, spark-ignited engine; and the fuel is a gasoline.

4. The method of claim 3 wherein the polyetheramine is represented by the formula RO(AO)_mR¹NR²R³; wherein R is a hydrocarbyl group of about 8 to about 30 carbon atoms; A is an alkylene group having 2 to 6 carbon atoms; m is a number from 1 to about 50; R¹ is an alkylene group having 2 to 6 carbon atoms; and R² and R³ are independently hydrogen, a hydrocarbyl group or -[R⁴N(R⁵)]_nR⁶ wherein R⁴ is an alkylene group having 2 to 6 carbon atoms, R⁵ and R⁶ are independently hydrogen or a hydrocarbyl group, and n is a number from 1 to 7.

5. The method of claim 4 wherein the polyetheramine is represented by the formula RO[CH₂CH(CH₃CH₂)O]_mCH₂CH₂CH₂NH₂; wherein R is an aliphatic group or alkyl- substituted phenyl group of about 8 to about 30 carbon atoms; and m is a number from about 12 to about 30.

6. The method of claim 5 wherein the polyetheramine is represented by the formula CH₃CH(CH₃)[CH₂CH(CH₃)]₂CH(CH₃)CH₂CH₂O[CH₂CH(CH₃CH₂)O]_rnCH₂CH₂CH₂NH₂ ;wherein m is a number from about 16 to about 28.

7. The method of claim 3 wherein the Mannich reaction product is prepared from an alkylphenol derived from a polyisobutylene, formaldehyde, and an amine that is an alkylenediamine or a dialkylamine.

8. The method of claim 7 wherein the alkylenediamine is ethylenediamine.

9. The method of claim 7 wherein the dialkylamine is dimethylamine.

10. The method of claim 3 wherein the fuel composition further comprises one or more additional additives.

11. The method of claim 3 wherein the fuel composition is prepared by adding the nitrogen-containing detergent as a bulk treatment to the fuel wherein the amount of the detergent in the fuel composition is 100 to 1,000 ppm by weight.

12. The method of claim 3 wherein the fuel composition is prepared by adding the nitrogen-containing detergent as an aftermarket treatment to the fuel wherein the amount of the detergent in the fuel composition is 1,000 to 10,000 ppm by weight.

13. The method of claim 12 wherein the nitrogen-containing detergent is a polyetheramine.

14. The method of claim 13 wherein the engine is operated under a clean-up cycle.

15. The method of claim 14 wherein the clean-up cycle generates engine speeds of at least 3,000 rpm.