EP1866396A1

EP1866396A1 - Use of detergent additives for reducing a particle amount in the exhaust gas of direct injection diesel engines

Info

Publication number: EP1866396A1
Application number: EP06723673A
Authority: EP
Inventors: Jörn KARL; Georg Schäper
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2005-03-24
Filing date: 2006-03-23
Publication date: 2007-12-19
Also published as: KR20070116149A; MX2007010950A; CN101146897A; EP1705234A1; AU2006226517B2; BRPI0609694A2; AU2006226517A1; NO20074587L; AR054240A1; JP2008534699A; CA2602275A1; WO2006100083A1; US20080196586A1

Abstract

The invention relates to using detergent additives for reducing a particle amount in the exhaust gas of direct injection diesel engines, in particular, in diesel engines provided a common rail injection system.

Description

Use of detergent additives to reduce the amount of particulates in exhaust emissions from direct injection diesel engines

description

The present invention relates to the use of detergent additives to reduce the amount of particulates in the exhaust emissions of direct injection diesel engines and more particularly diesel engines with common rail injection systems.

In direct-injection diesel engines, the fuel is injected through a directly into the combustion chamber-reaching multi-hole injection nozzle of the engine and finely distributed (nebulized), instead of being introduced as in the classic (chamber) diesel engine in a vortex or vortex chamber. The advantage of direct-injection diesel engines lies in their high performance for diesel engines and yet low consumption. In addition, these engines achieve a very high torque even at low speeds.

Essentially, three methods are currently used to inject the fuel directly into the combustion chamber: the conventional distributor injection pump, the unit injector system and the common rail system.

In the common-rail system, the diesel fuel is pumped by a pump with pressures of up to 2000 bar into a high-pressure line, the common rail (literally "common line"). injecting the fuel directly into the combustion chamber, where full pressure is always available on the common rail, allowing for multiple injection or a special injection mode, while the other injection systems only allow one injection Substantially divided into three groups: (1) pilot injection, which substantially achieves softer combustion so that hard combustion noise ("nailing") is reduced and engine running appears quiet; (2.) main injection, which is responsible in particular for a good torque curve; and (3.) post-injection, which provides in particular for a low NO _x value. In this post-injection, the fuel is usually not burned, but evaporated by residual heat in the cylinder. The resulting exhaust gas / fuel mixture is transported to the exhaust system, where the fuel in the presence of suitable catalysts acts as a reducing agent for the nitrogen oxides NO _x . Due to the variable, cylinder-specific injection of the common rail injection system, the pollutant emissions of the engine, such as the emission of nitrogen oxides (NO _x ), carbon monoxide (CO) and in particular of particles (soot) can be positively influenced. This makes it possible, for example, that engines equipped with common-rail injection systems can theoretically meet the Euro 4 standard even without an additional particle filter.

The Euro 4 emission standard (EU 4), which should lead to improved air purity in Europe, requires compliance with certain limit values, which must be complied with not only at the factory setting but also after the engine has run for 100,000 km and are measured under certain test conditions become. For example, the diesel particulate emissions limit is 0.025 g / km.

Applicant's experiments have found that in the course of engine operation direct injection diesel engines, and in particular those with a common rail injection system, increase particulate emissions. This is attributed, inter alia, to the formation of deposits in the injection system. For example, coking deposits may form on the injection nozzle; but it also comes to deposits on other parts of the injection system. In particular, deposits are formed in the injectors, causing them to exhibit a different response, thereby no longer injecting the fuel at the correct dosage, i. the injected amount deviates up or down from the original setting. The deposits can also cause the fuel to be insufficiently fine, d. H. no longer with a sufficiently small droplet size, and / or is no longer fogged with the right geometry. Overall, the formation of deposits to the fact that with increasing mileage, the combustion is always suboptimal, especially incomplete and thus under coking / soot formation, which contributes to the fact that the amount of particulates in the exhaust emissions of the engine increases and ultimately the limits of the Euro 4 norm should not be maintained for long periods of time or only with the help of elaborate particulate filter.

It was therefore an object of the present invention to provide additives which reduce the particle output increase during engine operation by e.g. Among other things, reduce or prevent the formation of deposits in the injection systems of direct injection diesel engines, especially in common rail injection systems.

The object is achieved by the use of an additive composition consisting of at least one detergent additive and optionally at least one Carrier oil for reducing the amount of particulates in exhaust emissions from direct-injection diesel engines.

In particular, direct-injection diesel engines are those with common-rail injection systems. In these, the reduction of particulate emissions is attributed, inter alia, to reducing or preventing the formation of deposits, particularly in the injectors.

In the context of the present invention, the term "particle" has the same meaning as in the Euro 4 standard detergent additives

The detergent additives are preferably amphiphilic substances which have at least one hydrophobic hydrocarbon radical having a number average molecular weight (M _n ) of from 85 to 20 000 and at least one polar group selected from:

(a) mono- or polyamino groups having up to 6 nitrogen atoms, at least one nitrogen atom having basic properties;

(b) nitro groups, optionally in combination with hydroxyl groups;

(c) hydroxyl groups in combination with mono- or polyamino groups, wherein at least one nitrogen atom has basic properties;

(d) carboxyl groups or their alkali metal or alkaline earth metal salts;

(e) sulfonic acid groups or their alkali metal or alkaline earth metal salts;

(f) polyoxy-C ₂ -C ₄ -alkylene groups represented by hydroxyl groups, mono- or

Polyamino groups, wherein at least one nitrogen atom has basic properties, or terminated by carbamate groups;

(g) carboxylic acid ester groups;

(h) succinic anhydride-derived moieties having hydroxy and / or amino and / or amido and / or imido groups; and or

(i) by Mannich reaction of substituted phenols with aldehydes and mono- or polyamines generated groups; The hydrophobic hydrocarbon radical in the above detergent additives, which provides the sufficient solubility in the fuel, has a number average molecular weight (Mn) of 85 to 20,000, especially from 113 to 10,000, especially from 300 to 5000. As a typical hydrophobic hydrocarbon radical, in particular in connection with the polar groupings (a), (c), (h) and (i), longer-chain alkyl or alkenyl groups, in particular the polypropenyl, polybutenyl and polyisobutenyl radicals each having Mn = 300 to 5000, in particular 500 to 2500, come , especially 700 to 2300, into consideration.

As examples of the above groups of detergent additives, the following are mentioned:

Mono- or polyamino groups (a) containing additives are preferably polyalkylene mono- or Polyalkenpolyamine based on polypropene or conventional (ie, with predominantly central double bonds) polybutene or polyisobutene with Mn = 300 to 5000. Is one in the preparation of the additives of polybutene or Polyisobutene with predominantly intermediate double bonds (usually in the beta and gamma position), the preparation route by chlorination and subsequent amination or by oxidation of the double bond with air or ozone to carbonyl or carboxyl compound and subsequent amination under reductive (hydrogenating ) Conditions. For amination here amines, such as. As ammonia, monoamines or polyamines, such as dimethylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine, are used. Corresponding additives based on polypropene are described in particular in WO-A-94/24231.

Further preferred monoamino groups (a) containing additives are the hydrogenation of the reaction products of polyisobutenes having an average degree of polymerization P = 5 to 100 with nitrogen oxides or mixtures of nitrogen oxides and oxygen, as described in particular in WO-A-97/03946.

Further preferred monoamino groups (a) containing additives are the polyisobutene epoxides by reaction with amines and subsequent dehydration and reduction of the amino alcohols obtainable compounds, as described in particular in DE-A-196 20 262.

Nitro groups (b), optionally in combination with hydroxyl groups, containing additives are preferably reaction products of polyisobutenes of average degree of polymerization P = 5 to 100 or 10 to 100 with nitrogen oxides or mixtures of nitrogen oxides and oxygen, as described in particular in WO-A-96/03367 and WO-A-96/03479 are described. As a rule, these reaction products are mixtures of pure nitropolyisobutenes (for example α, β-dinitropolyisobutene) and mixed hydroxynitropolyisobutenes (for example α-nitro-β-hydroxy-polyisobutene).

Hydroxyl groups in combination with mono- or polyamino groups (c) containing additives are in particular reaction products of polyisobutene epoxides, obtainable from preferably predominantly terminal double bonds containing polyisobutene having Mn = 300 to 5000, with ammonia, mono- or polyamines, as in particular in EP A-476 485 are described.

Carboxyl groups or their alkali metal or alkaline earth metal salts (d) containing additives are preferably copolymers of C ₂ -C ₄₀ olefins with maleic anhydride having a total molecular weight of 500 to 20,000, their carboxyl groups wholly or partially to the alkali metal or alkaline earth metal salts and a remainder the carboxyl groups are reacted with alcohols or amines. Such additives are known in particular from EP-A-307 815. Such additives are primarily used to prevent valve seat wear and, as described in WO-A-87/01126, can be advantageously used in combination with conventional fuel detergents such as poly (iso) butenamines or polyetheramines.

Sulphonic acid groups or their alkali metal or alkaline earth metal salts (e) containing additives are preferably alkali metal or alkaline earth metal salts of a sulfosuccinic acid alkyl ester, as described in particular in EP-A-639 632. Such additives are primarily used to prevent valve seat wear and can be used to advantage in combination with conventional fuel detergents such as poly (iso) butenamines or polyetheramines.

Polyoxy-C ₂ -C ₄ alkylene groupings (f) containing additives are preferably polyether or polyetheramines, which by reaction of C ₂ -C ₆₀ alkanols, C ₆ -C ₃₀ alkanediols, mono- or di-C ₂ - C ₃ o-alkylamines, CrCao-Alkylcyclohexanolen or CrC ₃ o-alkylphenols with 1 to 30 moles of ethylene oxide and / or propylene oxide and / or butylene oxide per hydroxyl group or amino group and, in the case of polyetheramines, by subsequent reductive amination with ammonia, monoamines or polyamines are available. Such products are described 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 products also meet carrier oil properties. Typical examples of these are tridecanol or Isotridecanolbutoxylate, Isononylphenolbutoxyl- late and Polyisobutenolbutoxylate and propoxylates and the corresponding reaction products with ammonia. Carboxylic ester groups (g) containing additives are preferably esters of mono-, di- or tricarboxylic acids with long-chain alkanols or polyols, especially those having a minimum viscosity of 2 tnm ² / s at 100 ⁰ C, as described in particular in DE-A-38 38 918 are described. As mono-, di- or tricarboxylic acids it is possible to use aliphatic or aromatic acids, especially suitable ester alcohols or polyols are long-chain representatives having, for example, 6 to 24 C atoms. Typical representatives of the esters are adipates, phthalates, isophthalates, terephthalates and trimellitates of iso-octanol, iso-nonanol, iso-decanol and of isotridecanol. Such products also meet carrier oil properties.

Succinic anhydride-derived groupings containing hydroxyl and / or amino and / or amido and / or imido (h) -containing additives are preferably corresponding derivatives of alkyl- or alkenyl-substituted succinic anhydride, and especially the corresponding derivatives of polyisobutenyl succinic anhydride, which Reaction of conventional or highly reactive polyisobutene with Mn = 300 to 5000 with maleic anhydride by thermal means or via the chlorinated polyisobutene are available. Of particular interest here are derivatives with aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine. The groups having hydroxyl and / or amino and / or amido and / or imido groups are, for example, carboxylic acid groups, acid amides of monoamines, acid amides of diamines or polyamines which, in addition to the amide function, still have free amine groups, succinic acid derivatives with a Acid and an amide, Carbonsäureimide with monoamines, Carbonsäureimide with di- or polyamines, which still have free amine groups in addition to the imide function, or diimides, which are formed by the reaction of di- or polyamines with two succinic acid derivatives. Such fuel additives are more particularly described in US-A-4,849,572.

By Mannich reaction of substituted phenols with aldehydes and mono- or polyamines generated groupings (i) containing additives are preferably reaction products of polyisobutene-substituted phenols with formaldehyde and mono- or polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine or dimethylaminopropylamine. The polyisobutenyl-substituted phenols can be derived from conventional or highly reactive polyisobutene having Mn = 300 to 5,000. Such "polyisobutene-Mannich bases" are described in particular in EP-A-831 141.

For a more detailed definition of the individual listed fuel additives is hereby made to the disclosures of the above-mentioned documents of the prior art express reference. Particularly preferred are detergent additives from group (h). These are preferably the reaction products of alkyl- or alkenyl-substituted succinic anhydrides, in particular polyisobutenylsuccinic anhydrides, with amines. It goes without saying that these reaction products are obtainable not only when substituted succinic anhydride is used, but also when substituted succinic acid or suitable acid derivatives, such as succinic acid halides or esters, are used.

Particularly preferred detergent additives are polyisobutenyl-substituted succinimides, especially the imides with aliphatic polyamines. Particularly preferred polyamines are diethylenetriamine, tetraethylenepentamine and pentaethylenehexamine, with tetraethylenepentamine being particularly preferred. The polyisobutenyl radical has a number-average molecular weight M _n of preferably 500 to 5000, more preferably from 500 to 2000 and in particular about 1000.

It goes without saying that the detergent additives can be used alone or in combination with at least one of the aforementioned detergent additives.

In a preferred embodiment, the detergent additive is used in combination with at least one carrier oil.

carrier oils

Suitable mineral carrier oils are fractions obtained in petroleum processing, such as bright stock or base oils with viscosities such as from class SN 500-2000; but also aromatic hydrocarbons, paraffinic hydrocarbons and alkoxyalkanols. Also useful is a fraction known as "hydrocrack oil" and derived from the refining of mineral oil (vacuum distillate cut having a boiling range of about 360 to 500 ° C, available from high pressure, catalytically hydrogenated and isomerized and dewaxed natural mineral oil). Also suitable are mixtures of the abovementioned mineral carrier oils.

Examples of synthetic carrier oils which can be used according to the invention are selected from: polyolefins (polyalphaolefins or polyethylenemolefins), (poly) esters, (poly) alkoxylates, polyethers, aliphatic polyetheramines, alkylphenol-initiated polyethers, alkylphenol-initiated polyetheramines and carboxylic acid esters of long-chain alkanols. Examples of suitable polyolefins are olefin polymers having Mn = 400 to 1800, especially based on polybutene or polyisobutene (hydrogenated or non-hydrogenated).

Examples of suitable polyethers or polyetheramines are preferably polyoxy-C ₂ -C ₄ -alkylene group-containing compounds which are obtained by reacting C ₂ -C ₆ -alkanols, C ₆ -C ₃₀ -alkanediols, mono- or di-C ₂ -C ₃ o-alkylamines, CrCao-alkylcyclohexanols or C _r C ₃ o-alkylphenols with 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 polyetheramines, by subsequent reductive amination with ammonia, Monoamines or polyamines are available. Such products are described in particular in EP-A-310 875, EP-A-356 725, EP-A-700 985 and US-A-4,877,416. For example, as polyetheramines, poly-C ₂ -C ₆ alkylene oxide amines or functional derivatives thereof can be used. Typical examples of these are tridecanol or Isotridecanolbutoxylate, Isononylphenolbutoxylate and Polyisobute- nolbutoxylate and propoxylates and the corresponding reaction products with ammonia.

Examples of carboxylic acid esters of long-chain alkanols are in particular esters of mono-, di- or tricarboxylic acids with long-chain alkanols or polyols, as described in particular in DE-A-38 38 918. As mono-, di- or tricarboxylic acids it is possible to use aliphatic or aromatic acids, especially suitable ester alcohols or polyols are long-chain representatives having, for example, 6 to 24 C atoms. Typical representatives of the esters are adipates, phthalates, isophthalates, terephthalates and trimellitates of isooctanol, isononanol, isodecanol and Isotridecanols, such as. For example, di (n- or iso-tridecyl) phthalate.

Further suitable carrier oil systems are described, for example, in DE-A-38 26 608, DE-A-41 42 241, DE-A-43 09 074, EP-A-0 452 328 and EP-A-0 548617, to which reference is hereby expressly made.

Examples of particularly suitable synthetic carrier oils are alcohol-started polyethers with about 5 to 35, such as. B. about 5 to 30, C ₃ -C ₆ alkylene oxide, such as. B. selected from propylene oxide, n-butylene oxide and i-butylene oxide units, or mixtures thereof. Nonlimiting examples of suitable starter alcohols are long-chain alkanols or long-chain alkyl-substituted phenols, where the long-chain alkyl radical is in particular a straight-chain or branched C _e -C ₈ -alkyl radical. Preferred examples are tridecanol and nonylphenol.

Further suitable synthetic carrier oils are alkoxylated alkylphenols, as described in DE-A-10 102 913.6. Preferred carrier oils are synthetic carrier oils, with polyethers being particularly preferred.

The detergent additive, optionally in combination with a carrier oil, is preferably supplied to the injection system with the diesel fuel.

In this case, the diesel additive, the detergent additive or the mixture of various detergent additives in an amount of preferably 10 to 2000 ppm by weight, more preferably from 20 to 1000 ppm by weight, more preferably from 50 to 500 wt. - ppm and in particular from 50 to 200 ppm by weight, eg from 70 to 150 ppm by weight, added.

When a carrier oil is used, it is added to the diesel fuel in an amount of preferably 1 to 1000 ppm by weight, more preferably 10 to 500 ppm by weight, and more preferably 20 to 100 ppm by weight.

In addition, the diesel fuel may contain other conventional co-additives, such as cold flow improvers, corrosion inhibitors, demulsifiers, dehazers, defoamers, cetane number improvers, combustion improvers, antioxidants or stabilizers, antistatics, metallocenes, metal deactivators, dyes, solvents, and the like. It is believed that the use of these additives has essentially no effect on the reduction of particulate emissions.

Suitable cold flow improvers are e.g. Copolymers of ethylene with at least one other ethylenically unsaturated monomer, e.g. Ethylene / vinyl acetate copolymers.

Suitable corrosion inhibitors are e.g. Succinic esters, especially with polyols, fatty acid derivatives, e.g. Oleic acid esters, oligomerized fatty acids, substituted ethanolamines and products sold under the trade name RC 4801 (Rhein Chemie Mannheim, Germany) or HiTEC 536 (Ethyl Corporation).

Suitable demulsifiers are, for example, the alkali metal or alkaline earth metal salts of alkyl-substituted phenol and naphthalenesulfonates and the alkali metal or alkaline earth metal salts of fatty acids, furthermore neutral compounds, such as alcohol alkoxylates, for example alcohol ethoxylates, phenol alkoxylates, for example tert-butylphenol ethoxylate or tert-pentylphenol ethoxylate , Fatty acids, alkylphenols, condensation products of ethylene oxide (EO) and propylene oxide (PO), for example in the form of EO / PO block copolymers, polyethyleneimines or else polysiloxanes. Suitable dehazers are, for example, alkoxylated phenol-formaldehyde condensates, such as, for example, the products NALCO 7D07 (Nalco) and TOLAD 2683 (Petrolite) available under the trade name.

Suitable antifoams are e.g. Polyether-modified polysiloxanes, such as the products available under the trade name TEGOPREN 5851 (Goldschmidt), Q 25907 (Dow Corning) and RHODOSIL (Rhone Poulenc).

Suitable cetane number improvers are e.g. aliphatic nitrates such as 2-ethylhexyl nitrate and cyclohexyl nitrate, and peroxides such as di-tert-butyl peroxide.

Suitable antioxidants are e.g. substituted phenols such as 2,6-di-tert-butylphenol and, 6-di-tert-butyl-3-methylphenol, and phenylenediamines such as N, N'-di-sec-butyl-p-phenylenediamine.

Suitable metal deactivators are e.g. Salicylic acid derivatives, such as N, N'-disalicylidene-1, 2-propanediamine.

Suitable solvents are e.g. non-polar organic solvents, such as aromatic and aliphatic hydrocarbons, for example, toluene, the xylene, "white spirit" and products sold under the trade name SHELLSOL (Royal Dutch / Shell Group) and EXXSOL (ExxonMobil), and polar organic solvents, for example alcohols such as 2-ethylhexanol, decanol and isotridecanol.

Preferred co-additives are demulsifiers, dehazers, defoamers, cetane improvers, antioxidants, metal deactivators, corrosion inhibitors and solvents.

These customary co-additives are added, if desired, in customary quantities.

Diesel fuels

The diesel fuels are, for example, crude oil raffinates instruments normally have a boiling range of 100 to 400 ⁰ C. These are mostly distillates with a 95% point up to 360 ⁰ C or even beyond. However, these may also be so-called "ultra low sulfur diesel" or "city diesel", characterized by a 95% point of, for example, a maximum of 345 ⁰ C and a maximum sulfur content of 0.005 wt .-% or by a 95% point of for example, 285 ⁰ C and a maximum sulfur content of 0.001 wt .-%. In addition to those available through refining Diesel fuels are those obtainable by coal gasification or gas liquefaction ("gas to liquid" (GTL) fuels). Also suitable are mixtures of the abovementioned diesel fuels with regenerative fuels, such as biodiesel or bioethanol.

The diesel fuels are particularly preferably those with a low sulfur content, ie with a sulfur content of less than 0.05% by weight, preferably less than 0.02% by weight, in particular less than 0.005% by weight. % and especially less than 0.001% by weight of sulfur.

The inventive use of detergent additives ensures that in the exhaust emissions of direct-injection diesel engines, especially diesel engines with a common-rail injection system, the increase in the amount of particulates is significantly lower than in the exhaust emissions of direct-injection diesel engines, which without the Use of detergent additives are operated. In particular, it is achieved that after 100,000 km of engine operation preferably at most 2.5 times the amount, more preferably at most 2.2 times the amount and in particular at most 2 times the amount of particles is included in comparison to the factory setting. In particular, the quantities of particulates contained in the output remain well below the limit of the Euro 4 standard. The values given refer to the exhaust emissions taken directly after the engine ("engine out"), ie before any particulate filter that may have been installed, which would reduce the amount of particulate matter in the exhaust. as it is set at the factory, ie before delivery to the dealer or end user (kilometer 0, as it were) The use according to the invention of detergent additives not only ensures compliance with the limit values for particulate emissions in accordance with Euro 4 standard, but also without additional fuel Particle filter over an engine running time of 100000 km guaranteed, but also for a much longer operating time.

example

An engine with a common-rail injection system was operated with a diesel fuel according to EN 590, which was additized with 90 ppm by weight of Kerocom PIBSI (a detergent additive from BASF AG containing a polyisobutylene succinimide), 70,000 km. For comparison, an identical engine with a diesel fuel according to EN 590, which contained no detergent additive, was also operated under identical conditions for 70,000 km. The amounts of particulates contained in the discharge were directly behind the Engine out, and the results are shown in the table below.

table

As the results show, the use of detergent additives leads to a reduced amount of particulates in the exhaust gases.

Claims

claims:

1. Use of an additive composition consisting of at least one detergent additive and optionally at least one carrier oil for reducing the amount of particulates in exhaust emissions of direct-injection diesel engines.

2. Use according to claim 1, for reducing the amount of particulates in exhaust emissions of diesel engines with common-rail injection systems.

3. Use according to one of the preceding claims, wherein the detergent additives are the reaction products of alkyl- or alkenyl-substituted succinic acids or derivatives thereof with amines.

4. Use according to claim 3, wherein the detergent additives are polyisobutenyl-substituted succinimides.

5. Use according to one of the preceding claims, wherein the detergent additives are used in combination with at least one carrier oil.

6. Use according to one of the preceding claims, wherein the particulate matter contained in the exhaust emissions of the diesel engines and measured directly behind the engine after 100000 km engine operation by a factor of at most 2.5 is higher than the factory setting and at the same time the limit value for the Particle quantity of Euro 4 norm is not exceeded.