NO121616B - - Google Patents

Description

Fuel for combustion engines.

The invention relates to another fuel

internal combustion engines, whose main component is a motor fuel with the boiling limits of petrol, and which contains an additive to prevent the formation of ice in the engine's carburettor.

Internal combustion engines are often prone to stalling, particularly when idling and not yet sufficiently warmed up after starting, due to ice formation in the carburettor. This ice formation is a consequence of the strong cooling of the moisture present in the combustion air during the evaporation of the motor fuel. This cooling increases with the volatility of the motor fuel, and the danger of ice formation has recently become greater, because petrol with low boiling points is increasingly used as motor fuel.

It is known to reduce the risk of ice formation in carburettors of internal combustion engines by adding certain water-soluble substances, e.g. alcohols, e.g. glycols, which lower the freezing point, to motor fuels, but to achieve somewhat satisfactory results relatively large concentrations of these additives are required in the motor fuels, e.g. 0.1-3 per cent. In many cases, this causes such large costs that it precludes commercial use of these additives. The complete water solubility of the additives which is required is a further disadvantage. It is not possible to prevent the motor fuels from coming into contact with water during transport and handling, because the tanks normally always contain a layer of water at the bottom. This water will extract a part of the motor fuel's water-soluble additive, and the fuel sold therefore often no longer contained a sufficient amount of the additive to prevent the formation of ice in the engine's carburettor.

The invention is to provide a fuel for internal combustion engines which contains a very small amount of additive, which effectively prevents the formation of ice in the carburettor of an internal combustion engine, and does not lose this property during the fuel's distribution and handling, because the additive is practically water soluble.

The fuel according to the invention contains a predominant amount of a fuel with the boiling point range of gasoline and a smaller amount of an N-alkyl-substituted alkylenediamine, and the main characteristic feature of the invention is that this N-alkyl-substituted alkylenediamine contains at least one alkyl group with at least 10 carbon atoms.

The motor fuel present in a fuel according to the invention is preferably petrol of the kind that is usually used to drive ordinary four-stroke or two-stroke engines, e.g. in automobiles, motor boats, aircraft or motorcycles and of which at least 50 per cent has been distilled in an ASTM distillation at 127° C, preferably at 116° C and especially at 104° C.

The fuel according to the invention contains only a very small amount of the N-alkyl-substituted alkylenediamine used. Usually a diamine concentration of 0.05 per cent is sufficient even under the most unfavorable conditions with regard to temperature, humidity and the volatility of the petrol, but a diamine concentration of 0.1 per cent can still occasionally be used. Diamine concentrations of 0.0005 % may already be sufficient, although concentrations of at least 0.001-0.0015, preferably at least 0.002 % are usually preferred. Particularly suitable are diamine concentrations of between 0.003 and 0.005 % and under special circumstances of no more than 0.02 %. , preferably only 0.01 per cent.

In a suitable embodiment of the fuel in question, this according to the invention contains an N-alkyl substituted alkylenediamine of the general formula

where R at least twice denotes a hydrogen atom and at least once an alkyl group with 10-30 carbon atoms and Ri an alkylene group with 2-6 carbon atoms and a straight carbon chain with at most 4 carbon atoms which at each end of the chain <!> is directly bonded to one of the compound's two nitrogen atoms.

It is of significant importance that the N-alkyl substituted alkylenediamine present in the fuel contains at least one alkyl group with at least 10 carbon atoms, because, when the alkyl group's carbon chain is shorter, the compound does not act sufficiently against the formation of ice in the carburettor, and its water solubility is too great, N- the alkyl substituents in the alkylenediamines used together suitably contain at least 12 carbon atoms and preferably no more than 30, preferably no more than 20 carbon atoms. In the most suitable embodiment of the fuel, the alkyl group of the N-alkyl substituted alkylene diamine contains 12-18 carbon atoms. The N-alkyl group or groups in the alkylene diamines can be saturated or unsaturated groups with a straight or branched carbon chain, and the alkylene group appropriately contains at most 4, preferably at most 3 carbon atoms.

Particularly suitable N-alkyl substituted alkylenediamines which can be used as an additive in a fuel according to the invention are mono-N-alkyl substituted alkylenediamines, especially propylene diamines, whose N-alkyl substituent has a straight carbon chain with 12-18 carbon atoms, or mixtures of such propylenediamines which can be produced by reaction of vegetable or animal fatty acids, e.g. of coconut fat, soya oil or tallow separated fatty acids, with ammonia and reduction of the amides formed in this way to amines, which are then reacted with e.g. acrylonitrile, croto- or methacrylonitrile, after which the reaction product is reduced to the corresponding mono-N-alkyl-substituted alkylenediamines. Such mixtures of N-alkyl-substituted alkylenediamines are available on the market as technical products with approx. 80 percent mono-N-alkyl-substituted 1,3-propylenediamines which are produced from coccus fatty acid or tallow fatty acid or soy fatty acid or lauric acid.

As N-alkyl substituted alkylenediamines, the fuel in question can also contain e.g. 3-laurylamino-1-butyl-amine, N,N'-didecyl-1,3-propanediamine, N-octadedecyl-1,3-propanediamine, N-hexadecyl-1,2-ethanediamine, N-oleyl-N '-dodecyl-1,3-propanediamine, N-hexadecyl-N'-methyl-1,2-propanediamine, N-decenyl-N'-sec-butyl-1,3-propanediamine or mixtures of these diamines.

In a suitable embodiment of the fuel in question, this contains, in addition to N-alkyl-substituted alkylenediamine, an addition of a synthetic lubricant, e.g. mixtures of poly-oxa-carbon hydrides, e.g. monoalkyl ethers of polyhydroxy-1,2-propylene diols (U.S. Patent 2,448,664) or monohydroxy-etherized aliphatic ethers of hydroxy-ethylene-hydroxy-1,2-propylene (U.S. Patent 2,425,755) or similar compounds known from U.S. patents 2,425,845, 2,520,611 and 2,520,612. The weight ratio between the synthetic lubricant and the N-alkyl-substituted alkylenediamine in the fuel is suitably between 0.25 and 500, but approximately equal amounts by weight of both additives are preferably used.

The fuel according to the invention can also contain other common petrol additives, e.g. anti-knock means, e.g. tetraethyl lead, iron carbonyl, dicyclopentadienyl iron, xylidene or N-methylaniline, rinse agents, e.g. ethylene dibromide or ethylene dichloride, agents for preventing the spark plugs from becoming dirty, e.g. tricresyl phosphate, dyes, agents that modify the course of combustion, e.g. alkylboronic acids or lower alkyl phosphates or alkyl phosphites, oxidation-preventing substances, e.g. N,N'-di-sec-butyl-phenylene-diamine, N-n-butyl-p-aminophenol or 2,6-di-tert-butyl-4-methylphenol, metal deactivators such as N,N'-di-salicylal- 1,2-propanediamine and anti-rust agents such as polymerized linolenic acid.

Example 1:

Experimentally, the effectiveness of various additives in preventing the formation of carburetor ice is determined by an ASTM-CFR test engine with a Chevrolet carburetor, Carter, Model No. WA-1-4138.

Petrol was used, of which 50 per cent had been distilled in an ASTM distillation at 93° C, and which, in addition to anti-knock and flushing agent, contained the following additives to prevent ice formation in the carburettor.

A. Isopropanol.

B. Technical N-alkyl substituted 1,3-propylenediamine, which was prepared from tallow fatty acid. C. Technical alkyl substituted 1,3-propylenediamine as. was produced from coccus fatty acid.

D. N-lauryl-1,3-propanediamine.

The air drawn into the engine's carburettor had a constant temperature of 5° C and a constant relative humidity of 75 per cent in all tests. Each test was started with a cold engine and with the carburettor's control damper for the first 3 minutes. in the 30° opening position, after which the damper is set in the idle position. The time before the engine stopped due to ice forming in the carburettor was then determined. By dividing this time by the time determined in the same way for the same petrol without anti-icing additive in the carburettor, the average value for the stopping time ratio obtained in a large number of trials was calculated.

The results appear in the following table.

Example 2:

When carrying out the experiments according to example 1 with 0.002, 0.005 and 0.01 percent N,N-didecyl-1,2-ethanediamine as additive with the formation of ice in the carburettor, similar results were obtained as with additive C in example 1.

Example 3:

When carrying out the tests according to example 1 with 0.001, 0.003 and 0.02 percent N-dodecyl-N'-ethyl-1,3-propanediamine as an additive against the formation of ice in the carburettor, similar results were obtained as with additive B in example 1.

Example 4:

To show that it is of significant importance that the N-alkyl substituted alkylenediamine used as an additive contains at least one alkyl group with at least 10 carbon atoms, the experiments according to example 1 were repeated with the following three other additions.

E. N,N'-bis-(2-ethylhexyl)-1,3-propane-diamine.

F. N,N-di-ethyl-1,3-propanediamine.

G. 2-methyl-1,3-propanediamine.

A concentration of 0.005 percent was used in each case. The average value for the stopping time ratio for the additive E was 0.8, for the additive F 1.2 and for the additive G 0.8.

Example 5: The water solubility of additions B and C, example 1, addition F, example 2, and of N,N-dimethyl-1,3-propanediamine, addition H, is determined by vigorous shaking of 2 liters of 0.01 percent. 's distilled water and electrometric titration of the aqueous extract. The iso-octane solution of additive B contained after shaking 0.008% additive, the iso-octane solution of additive C 0.0085% additive, the iso-octane solution of additive F 0.005% additive and the iso-octane solution of additive H 0.004% additive.

Example 6:

To determine whether the N-alkyl-substituted alkylenediamines used as anti-icing additives in the carburettor had a harmful effect on internal combustion engines or caused deposits in the carburettor and in the intake pipe between

this and the engine, were driven approx. 8000 km with 10 different ones

automobiles that were fueled with commercial gasoline that did not contain additives

against the formation of ice in the carburettor. Then it was

each engine with the carburettor and the intake pipe examined in particular with regard to

deposits, after which it again during

2 months were driven approx. 8000 km with each

car with the same petrol, but now added 0.003

% of addition C according to example 1. Ved

the subsequent examination of each engine with the carburettor and intake pipe

no harmful effect was found, in particular

not with regard to deposits.

Claims (9)

1. Fuel mixture for use i internal combustion engines with carburetors, which prevent ice formation and which contain a predominant amount of a fuel with the boiling point range of gasoline, as well as a smaller amount of an N-alkyl-substituted alkylenediamine, characterized in that the N-alkyl-substituted alkylenediamine contains at least one alkyl group with at least 10 carbon atoms. 2. Fuel according to claim 1, characterized in that per million parts by weight contains 5-1000 parts by weight, preferably 10-500 parts by weight of the N-alkyl substituted alkylenediamine. 3. Fuel according to claim 1 or 2, characterized in that it contains an N-alkyl substituted alkylenediamine of the general formula of which R at least twice denotes a hydrogen atom and at least once an alkyl group with 10-30 carbon atoms and Ri an alkyl group with 2-6 carbon atoms and a straight carbon chain with at most 4 carbon atoms which at each end of the chain is directly bonded to one of the compound's two nitrogen atoms. 4. Fuel according to claims 1-3, characterized in that the alkylene diamine's alkyl group or alkyl groups have 12-18 carbon atoms. 5. Fuel according to claims 1-4, characterized in that the alkylene group of the alkylenediamine is a propylene group. 6. Fuel according to claims 1-5, characterized in that the alkylenediamine is a mono-N-alkyl substituted alkylenediamine. 7. Fuel according to claims 1-5, characterized in that the alkylenediamine is a N,N- or an N,N'-dialkyl substituted alkylenediamine. 8. Fuel according to claims 1-7, characterized in that it contains a mixture of N-alkyl substituted alkylenediamines with at least one alkyl group with at least 10 carbon atoms. 9. Fuel according to claims 1-9, characterized in that it contains a synthetic lubricant part as a further addition.