DE972053C - Cylinder lubricant for internal combustion engines operated with sulfur-containing fuels with a sulfur content of at least 0.01 to over 5 percent by weight - Google Patents

Description

ISSUED APRIL 7, 1960

N 11620 IVcI 23 c

is used

The invention relates to cylinder lubricants composed of certain water-in-oil emulsions for fuels containing sulfur with a sulfur content of at least o, or to Internal combustion engines operated over 5 percent by weight, in particular diesel engines.

Diesel engines have already been lubricated with emulsions of oil and water, the water being used for its cooling effect. Also, it has been proposed cylinder \ ^r on steam engines to lubricate either with an emulsion consisting of a the aqueous, potassium carbonate or Calciumhvdroxvd containing solution and a mineral lubricating oil, or contains a ashless emulsion Voltol as emulsifier.

It has also been proposed to use the lubricating properties of water-in-oil emulsions, in particular Emulsions with an oil content below 50%, by adding a nitrite, in particular Calcium nitrate, in amounts of 0.1 to 1% to improve.

For the production of lubricating oil emulsions one has to use magnesium salts of Products of the oxidation of paraffin hydrocarbons such as fatty acids with at least

909 744/3

16 carbon atoms as an oil-soluble emulsifier recommended.

Furthermore, suspensions of a chromate are in

a lubricant, which can be an emulsion of oil and water, known, the chromate for Combating corrosion, which z. B. occurs in a gasoline engine is used.

Finally, it is known to use water-soluble mineral oils which, after they have been emulsified to form oil-in-water emulsions are used in metalworking, inorganic water-soluble chromates, in particular potassium, sodium or ammonium chromate, optionally in combination with water-soluble, inorganic nitrites, in particular alkali nitrites or ammonium nitrite, means to incorporate a solubilizer.

If internal combustion engines are operated with fuels that are relatively have a high sulfur content, the particular problem of much greater wear occurs compared to cases where a sulfur free or practically sulfur free fuel Is used. This wear and tear is caused, among other things, by corrosion, in particular corrosion the cylinder walls and piston rings. Because fuels with a relatively high Sulfur content is often used in diesel engines, particularly marine diesel engines, so is the problem mentioned is of particular importance in this case.

To understand the harmful effects of sulfur in motor fuel on the cylinders of a To reduce internal combustion engine, it has already been proposed to lubricate oils in such motors are used to add basic substances, such as e.g. B. aniline and guanidine. It has now been found that water-in-oil emulsions whose oil phase has the viscosity of a Lubricating oil and an oil solution known per se Contains emulsifier and its aqueous phase at least 0.2 mol / l of a nitrate or nitrite of a divalent metal, preferably an alkaline earth metal, or of magnesium, zinc or cadmium contains, excellent cylinder lubricant for fuels containing sulfur with a sulfur content from at least 0.01 to over 5 percent by weight (calculated as elemental sulfur) represent operated internal combustion engines. When using these emulsions as cylinder lubricants in internal combustion engines that run on fuels with said sulfur content are operated, a considerable reduction in wear is achieved.

The emulsions have a particularly beneficial effect on internal combustion engines that run on fuels with a sulfur content of at least 0.1 percent by weight, calculated as elemental sulfur, operate. In many cases fuels are used that have a sulfur content of 0.5 to 3.5 percent by weight, in particular 1 to 3 percent by weight. The sulphurous fuels can be both mineral oil distillates and residual oils. The cylinder lubricants of the invention can also be used in engines that run on gaseous fuels whose sulfur content is at least 0.01 percent by weight and in particular 0.1 percent by weight and more is.

The cylinder lubricants according to the invention are particularly suitable for combustion. ¹ * - prime movers with separate cylinder lubrication. The water-in-oil emulsions can, however, also be used in internal combustion engines with centrifugal lubrication. In the latter case, it may be desirable to prevent the evaporation of water from the water-in-oil emulsions at high crankcase temperatures and, at the same time, the separation of the dissolved salt from the water-in-oil emulsion. This can e.g. B. can be achieved by a special cooling device.

The cylinder lubricants according to the invention contain the salt in the aqueous phase of the Emulsion preferably in a concentration of more than 0.5 mol per liter and in particular in one Concentration of at least 1 mole per liter. For this reason, salts are preferred that are one have great water solubility. Depending on your requirements, the water solubility of the salt can be increased by the simultaneous addition of an auxiliary substance which increases the water solubility of the salt improved. It may also be desirable to take care that the salt concentration in the aqueous phase of the water-in-oil emulsion is not so high that the saturation concentration is any temperature to which the emulsion is exposed in the engine is exceeded. It is not always a disadvantage, however, if the aqueous phase of the water-in-oil emulsion also contains undissolved, contains dispersed or crystallized salt in addition to the dissolved salt.

The total amount of salt that is used in the emulsion is generally greater, the higher the sulfur content of the fuel with which the combustion engine to be lubricated is operated.

The aqueous phase of the water-in-oil emulsions can be mixtures of the salts mentioned with one another or with other salts of divalent metals.

The viscosity of the oil component of the lubricant cylinder according to the invention can vary within wide limits and is generally at least 20 cSt at 50 ⁰ C. It can not find the common mineral lubricating oils as the oil component used; so are z. B. residue oils and distillate oils are suitable. Synthetic oils with the viscosity of a lubricating oil can also be used. Both synthetic lubricating oils of the hydrocarbon type, e.g. B. polymer oils or alkylated oils, as well as synthetic lubricating oils of another type, such as esters. The oil component of the emulsions can also consist of mixtures of the different types of lubricating oils. Such mixtures can also contain fatty oils. The common ones

Lubricating oil additives, such as ζ. B. Pour point depressants, viscosity index improvers, extreme pressure additives, Oxidation inhibitors, anti-foaming agents, cleaning agents and corrosion inhibitors can be used in the oil phase be present.

The ratio of the amount of aqueous phase to the amount of oil phase in the inventive Cylinder lubricants can vary within wide limits. In most cases the

ίο proportion of the aqueous phase ι up to 50 percent by weight of the entire emulsion. In general, the amount of the aqueous phase is preferred kept relatively low in order to keep the viscosity of the entire emulsion low. The smaller the The proportion of the aqueous phase in the total emulsion, the greater the salt concentration in general the aqueous phase. However, if the manufacture of a viscous water-in-oil emulsion is required, so the amount of the aqueous phase can also be more than 50 percent by weight, e.g. B. 80 percent by weight, of the entire emulsion.

The emulsions are produced by means of one or more emulsifiers. Any emulsifier that is suitable for emulsifying an aqueous phase in an oil phase can be used. In the Use of the emulsion as a cylinder lubricant in an internal combustion engine is allowed no harmful substances are formed from the emulsifiers.

Suitable emulsifiers are the esters of polyhydric alcohols, such as. B. the mono and Diesters of glycerine with higher fatty acids, such as glycerine monooleate, glycerine monostearate, glycerine monoricinoleate, Diethylene glycol monolaurate, diethylene glycol monooleate, diethylene glycol monostearate and sorbitol mono- and polyoleates, polyoxyethylene sorbitol esters of oleic acid or other fatty acids or resin acids, oil-soluble polyvalent ones Metal salts, especially the alkaline earth metals, such as. B. those of fatty acids, or naphthenic acids organic sulfonic acids such as petroleum sulfonic acids. Other examples of suitable emulsifiers are Resin acids, wool fat, oxidized vegetable oils, lecithin and condensation products of a polyvalent one Alcohol, a higher fatty acid and a polybasic carboxylic acid that are soluble in oil, however are practically insoluble in water.

The emulsifiers are usually used in amounts of ι to 5 percent by weight, calculated on the Whole emulsion, used when they are of the nonionic type, while emulsifiers of the Type of metal soaps usually in amounts of 0.05 to 0.5 percent by weight and in particular λ'οη ο, ΐ percent by weight (calculated as metal) can be used.

It is often advantageous to use a combination of two or more emulsifiers. A suitable combination of emulsifiers consists of a polyvalent metal salt of an organic sulfonic acid and a polyvalent metal salt of an aromatic carboxylic or oxycarboxylic acid, which is substituted by one or more alkyl groups having at least 8 and in particular at least 12 carbon atoms, and / or a polyvalent metal phenolate which is substituted by one or more alkyl groups having at least 8 and in particular at least 12 carbon atoms is substituted. By means of the combinations of emulsifiers mentioned, very stable emulsions can be produced even when relatively small amounts of the emulsifiers are used. In many cases, amounts of emulsifier which together contain no more than 0.05 to 0.5 percent by weight of polyvalent metal, calculated on the oil phase, are sufficient. If desired, however, larger amounts of the emulsifiers can also be used.

The ratio of the amounts of the two types of emulsifiers, namely a polyvalent metal salt of an organic sulfonic acid on the one hand and a other polyvalent metal salt, such as. B. a polyvalent metal salt of an aromatic oxycarboxylic acid, substituted by one or more alkyl groups having at least 12 carbon atoms is, on the other hand, can fluctuate within wide limits. In general it can be stated that very stable water-in-oil emulsions are obtained when the weight ratio of two types of emulsifiers are between 95: 5 and 5:95. Preferred is a weight ratio between 85:15 and 15:85.

The salts of polyvalent metals mentioned, which are suitable as emulsifiers, are preferred Salts of the alkaline earth metals or of magnesium, cadmium or zinc. However, other salts can Polyvalent metals are also used as emulsifiers. The emulsifiers used in the Said combination used can either be of the same polyvalent metal or come from various polyvalent metals. An example of the latter case is the combination of the calcium salt of an organic sulfonic acid with the zinc salt of an alkylated aromatic Oxycarboxylic acid.

Although polyvalent metal salts of various types of sulfonic acids as a component Can be used in the emulsifier mixture, the salts of polyvalent metals of oil-soluble petroleum sulfonic acids are preferred. Other sulfonic acids, the polyvalent metal salts of which are suitable emulsifiers, will be obtained by sulfonation of aromatic hydrocarbons, such as. B. the alkylated benzenes or alkylated naphthalenes. It is also possible to use an aromatic extract of a hydrocarbon oil to alkylate and sulfonate and the product obtained after its conversion into a To use salt of a polyvalent metal as an emulsifier.

The polyvalent metal salts of an organic sulfonic acid can be either neutral or be basic sulfonates.

The other emulsifier component of the above combination of emulsifiers is e.g. B. a polyvalent metal salt of an alkylated

Salicylic acid, the alkyl groups of which have 14 to 18 carbon atoms have, wherein the number of alkyl groups is preferably 1 or 2, or they is a polyvalent metal salt of an alkylphenol-aldehyde condensation product.

This other emulsifier component can also consist of a mixture of a salt of an alkylated one aromatic oxycarboxylic acid with an alkylphenolate exist. A very suitable emulsifier component is e.g. B. a mixture of a multivalent Metal salt of alkyl salicylic acids with alkyl phenclates. These are obtained by alkali alkylphenolates are reacted with carbon dioxide according to the Kolbe-Schmidt method brings, whereby a large part of the phenolates is converted into the salicylates and by the obtained mixture with an inorganic salt of a polyvalent metal or with an oxide or its hydroxide treated. In this way, mixtures of a greater proportion of basic salicylates of polyvalent metals and a smaller proportion of alkylated phenates obtain. Such basic mixtures are very suitable emulsifiers, since the stability of Water-in-oil emulsions are enlarged by the high basicity of the emulsifier. The basicity of Mixtures of the alkyl salicylates and alkyl phenates can be further enlarged if the reaction product, which is obtained according to the Kolbe-Schmidt method as described above, not immediately with an inorganic salt or an oxide or hydroxide of a polyvalent one Metal is reacted further, but first with an alkali metal, an alkali hydroxide or an alkali alcoholate is treated, whereupon, if desired, a second reaction with carbon dioxide connected according to the Kolbe-Schmidt method will.

Combinations of oil-soluble petroleum sulfonates of polyvalent metals with metal-free emulsifiers or stabilizers are also very suitable for the cylinder lubricants according to the invention.

An example of this is the combination of an oil-soluble petroleum sulfonate with a polyvalent one Metal with a condensation product of a polyhydric alcohol, a higher fatty acid and a polybasic carboxylic acid which is oil soluble but practically insoluble in water. The emulsions can be prepared in a simple manner by adding the aqueous salt solution with stirring to the oil phase which contains the emulsifier or emulsifiers and depending on If desired, the mixture is further homogenized. The emulsion can be homogenized by running it through a colloid mill or gear pump. By means of such homogenization treatment For example, the mean size of the dispersed particles can be reduced considerably, in particular to 2 μ or less.

With the help of suitable emulsifiers, such as. B. of the above combinations, it is possible Produce water-in-oil emulsions whose dispersed particles do not turn into larger lumps accumulate and therefore do not settle, so that no layers are formed. Such Emulsions can be stored for weeks and even months without flocculation or flocculation settling occurs.

The excellent properties of the invention Cylinder lubricants are illustrated by the following examples.

example 1

Water-in-oil emulsions were produced in which the oil component was a lubricating oil distillate which was extracted according to the Edeleanu process and which had a viscosity of 42 cSt at 60 °. Glycerol monooleate was added to this oil base in an amount of 2 percent by weight based on the oil. Then 10 parts by weight of an aqueous salt solution was added to 100 parts by weight of the oil containing the emulsifier. The type and amounts of the salts used in the various water-in-oil emulsions are listed in the table below. After the aqueous salt solution was emulsified by stirring in the oil, ^r w as the emulsion twice through a gear pump. Various water-in-oil emulsions were thus obtained by using different salts.

These emulsions were used to lubricate the cylinders of a two-stroke diesel engine from gs 20 hp that ran at a speed of 600 revolutions per minute. In every attempt it was a gas oil with a sulfur content of 1 percent by weight, calculated as elemental sulfur, used as fuel.

The engine ran for 8 hours in each test and was then examined.

To study the properties of water-in-oil emulsions as cylinder lubricants, alternated two successive experiments with a water-in-oil emulsion and carried out two successive tests with the lubricating oil contained therein.

The effect of the various tested water-in-oil emulsions was compared with the effect of the lubricating oil it contains by determining the weight loss of the piston rings became. This weight loss is a measure of the wear and tear. In the following table the As the results of the tests show, is that which occurred when using the water-in-oil emulsions Wear expressed as a percentage of the wear that occurs when that Lubricating oil is used as such as a cylinder lubricant, so the wear in the latter Case with 100 was used.

In the table mentioned there is also an estimate of the contamination of the cylinder walls during of the various experiments listed, with the number 10 a completely pure and the number ο one marked completely black wall.

Type of salt
in the emulsified solution

concentration

of the salt in the aqueous phase wear

first
Piston ring

remaining
Piston rings

Estimation of the contamination of the cylinder walls

no salt in the emulsified
aqueous phase dissolved ...

K ₂ CO,

Ca (NO ₃ ).,

Ca (NO.,),

2.25 mol / l 1.13 mol / l 1.13 mol / l 120

"δ 'öS
60

100
65

55 45

3
9

8th
8th

The table shows that when water-in-oil emulsions are used, their aqueous phase is a Containing nitrate or nitrite of a divalent metal, considerably better results can be obtained than when using water-in-oil emulsions whose aqueous phase has no salt or Contains potassium carbonate. It can also be seen from the table that the results obtained by means of Water-in-oil emulsions are obtained whose aqueous phase is a nitrate or a divalent nitrite Containing metal are better than those when the lubricating oil is used as such can be obtained as cylinder lubricants.

Example 2

To determine the reduction in wear and tear depending on the salt concentration For the water-in-oil emulsions, a series of tests was carried out with calcium nitrite successively the following nitrite concentrations: 9, 20, 40, 80, 157 and 350 millimoles per kilogram of the total emulsion.

The emulsions consisted of 70 percent by weight of the oil component and 30 percent by weight the aqueous phase in which the calcium nitrite was dissolved. The oil component was that in Example 1 described lubricating oil distillate, which contained 2 weight percent glycerol monooleate as an emulsifier.

The water-in-oil emulsions were used as cylinder lubricants in a four-stroke diesel engine of 50 hp that rotates at a speed of 250 ran per minute. The motor fuel had a sulfur content of 2.5 percent by weight.

In each test, the wear was determined by determining the Fe content of the cylinder wall Dripping oil measured. The engine ran when each emulsion was used initially 5 hours to reach the steady state, followed by a sample every half hour of the oil dripping off the cylinder wall was examined. For a period of 3 hours Six specimens were tested for their Fe content in this way. The mean of the six determinations was taken as a measure of the wear and tear that occurred.

. The experimental results obtained in the above else W ^T are shown in the curve.

The Fe content of the dripping oil is dependent on the salt concentration Emulsion expressed in millimoles per kilogram of total emulsion has been reported. the

Claims (8)

PATENTA N S PR C C HE numerical values actually determined are indicated in the graphic representation by small circles. The graph shows that with small salt concentrations no reduction in wear is achieved, while above a certain concentration the desired effect increases as the salt content of the emulsion increases. Although the fuel used had the high sulfur content of 2.5 percent by weight. a clear effect was already obtained with a concentration of 60 millimoles calcium nitrite per kilogram of the total emulsion. In the emulsion, which consisted of 30 percent by weight of the aqueous phase, the amount of millimoles per kilogram of the emulsion corresponds to a concentration of calcium nitrite of about millimoles, i.e. H. 0.2 mol per liter of the aqueous phase. 1. Cylinder lubricant for fuels containing sulfur with a sulfur content internal combustion engines operated from at least 0.01 to over 5 percent by weight, standing from a water-in-oil emulsion, the oil phase of which has the viscosity of a lubricating oil and contains an oil-soluble emulsifier known per se and in the aqueous phase thereof Nitrate or nitrite of a divalent metal, preferably an alkaline earth metal or of Magnesium, zinc or cadmium in amounts of at least 0.2 mol per liter, preferably more than 0.5 moles per liter, is dissolved. 2. Cylinder lubricant according to claim 1, characterized in that the viscosity of the oil component is at least 2ocSt at 50 ⁰ . 3. cylinder lubricant according to claim 1 and 2, characterized in that the emulsion from ι to 50 parts by weight of the aqueous phase and 99 to 50 parts by weight of the oil phase consists. 4. cylinder lubricant according to claim 1 to 3, characterized in that the emulsion as an emulsifier, an oil-soluble salt of a polyvalent metal of an organic sulfonic acid, preferably a petroleum sulfonate, alone or in admixture with a salt of a polyvalent one Metal of an aromatic carboxylic or oxycarboxylic acid and / or a phenolate of a polyvalent metal, which by 909 744/3 one or more alkyl groups having at least 8 carbon atoms are substituted. 5. cylinder lubricant according to claim 4, characterized in that the salt is one polyvalent metal of an organic sulfonic acid in a weight ratio between 85:15 and 15:85 with a polyvalent metal salt of an aromatic oxycarboxylic acid combined by one or more alkyl groups having at least 12 carbon atoms is substituted. 6. cylinder lubricant according to claim 4 or 5, characterized in that the salt - A polyvalent metal of an aromatic oxycarboxylic acid is an alkyl salicylate whose Alkyl groups have 14 to 18 carbon atoms. 7. cylinder lubricant according to claim 1 to 6, characterized in that the emulsion as an emulsifier, a condensation product of a polyhydric alcohol, a higher fatty acid and a polybasic carboxylic acid which is oil soluble but practically insoluble in water is. 8. cylinder lubricant according to claim 1 to 7, characterized in that the middle Diameter of the individual particles of the dispersed aqueous phase is not more than 2 μ. Considered publications:
German Patent Nos. 885453, 871047, 879274, 909022; French Patent No. 781,378;
Oil and Coal, 1942, pp. 176 to 178. 1 sheet of drawings © 60 »578/443 7.56 (909 744/3 3.60)