RU2280066C2 - Gasoline fuel additive - Google Patents

Abstract

FIELD: petrochemistry.

SUBSTANCE: invention relates to additives for gasoline boiling-range motor fuels used in carburetor and injector internal combustion engines. Additive contains 17.7-22.4% 1,3-diphenylurea, 20-22% oxygenates in the form of C₂-C₅-alcohol mixture, 01.0.3% dicarboxylic acid esters, and 0.02-0.05% phenol-type ashless antioxidant, the rest being solvent in the form of kerosene-gasoline mixture.

EFFECT: improved burning conditions for different molecular-structure hydrocarbons and reduced CO and NO_x emission in exhaust.

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Description

The invention relates to petrochemistry, in particular to additives for motor fuels of the gasoline boiling range used in carburetor and injection internal combustion engines.

It is known that motor fuels of the gasoline boiling range contain various additives, including those intended:

to increase the resistance of gasoline-based fuel mixtures to detonation with a corresponding reduction in wear of the cylinder-piston group of internal combustion engines;

to reduce exhaust toxicity;

to reduce the specific cost of motor fuel due to the completeness of combustion of the charges of air-fuel mixtures.

Various oxygen-containing organic substances, oxygenates, including alcohols (methanol, ethanol, etc.), ethers (methyl tert-butyl, ethyl tert-butyl, etc.) are used to increase the resistance of the gasoline boiling range fuels to detonation and reduce exhaust toxicity. .), as well as other compounds (see the book. A. Danilov “The use of additives in fuels for automobiles.” Reference publication, M., Chemistry, 2000, p. 54).

A common disadvantage of oxygenates is the low heat of combustion with respect to the hydrocarbons of the gasoline boiling range, as well as the increased emission of nitrogen oxides (NO _x ) in the exhaust gases (OG).

In view of these circumstances, multicomponent additives are used in motor fuels of the gasoline boiling range, both based on oxygen-containing organic substances of different molecular structures, and additives based on oxygenates and other components.

Known additive for motor fuels of the gasoline boiling range containing oxygenates in the form of alcohols C ₃ -C ₅ and / or their derivatives esters, N-methylaniline, ferrocene, aniline, the additive "Automag" (patent RU No. 2132359,1999). The specified additive is introduced into motor gasolines in a concentration of 0.2-20 wt.%.

The disadvantage of this additive is the presence of iron-containing compounds in it, which, when used in motor fuels, leads to increased carbon formation on the candles of the internal combustion engine and additional deposits on the details of the piston-cylinder group.

Known multifunctional additive for motor fuel gasoline boiling range containing N-methylaniline, aliphatic alcohols C ₃ -C ₅ detergent based on amide, antioxidants in the form of 2,6-di-tert-butyl-4-methylphenol or a mixture of shielded phenols in toluene, ethyl ether (Eurasian patent No. 000882, 2000). The additive is introduced into automobile fuel.

The disadvantages of this additive and fuel containing it are:

the need to use a stabilizer in the form of aliphatic C ₃ -C ₅ alcohols, which increase the cost of the additive;

relatively low antiknock effectiveness;

insufficient chemical stability of the composition during storage.

To increase the detonation resistance of motor gasolines, to reduce the oxidation of the composition during storage, an additive is proposed containing aromatic amine (R ₃ C ₆ H ₄ -NR ₁ R ₂ ), oxygenate (R ₄ -OR ₅ ) and hydrazine in the mass ratio of aromatic amine: oxygenate components : hydrazine = (0.5-70): (93.5-29.995): (0.005-2) (RU patent No. 2184767, 2002).

The use of aromatic amines in motor gasolines increases their knock resistance.

At the same time, aromatic amines have an increased tendency to gum formation on the parts of the cylinder-piston group, which increases the wear of the latter, and does not contribute to a decrease in the emission of nitrogen oxides (NO _x ) in the exhaust. The use of a significant amount of oxygenate in this additive will lead to a significant increase in the emission of these gases in the exhaust gas, which is essential for the urban driving mode.

In addition, in the case of progressive cracking of hydrocarbons of various molecular structures that are part of the fuels characteristic of the engine’s combustion chamber, the effect of aromatic amines on the combustion process as a whole is not significant due to their insufficient thermochemical resistance.

Known composite additives to motor fuels of the gasoline boiling range, which are designed to reduce the emission of CO, CH and NO _x and at the same time help to equalize the temperature field in the cylinders of the combustion engine, thereby improving the combustion process of hydrocarbons of various molecular structures (patent WO No. 96/40844, patent RU No. 2187541).

Additive according to patent RU No. 2187541 contains at least one ionic-bonded copper compound, at least one ion-bonded zinc compound, while it contains 0.03-0.7 mol of zinc per mole of copper and additionally contains at least one organic substance, for example, from the group consisting of oxyquinoline, cupferon, neocupferon and an arbitrary complexon from a variety of aminopolycarboxylic acids, which provide dissolution of metal salts in fuel hydrocarbons.

This additive has a pronounced disadvantage in terms of its multicomponent nature and the need to select an arsenal of components, taking into account the specificity of the given compounds for a specific composition of the fuels used, which increases the cost of the additive and limits its use for liquid fuels of a gasoline boiling range with an arbitrary chemical composition.

The closest analogue of the claimed technical solution is an additive to the motor fuel of a gasoline boiling range containing cyclic aromatic compounds in the form of polyunsaturated aliphatic or acyclic compounds with double bonds (vitamin A), derivatives of dihydrobenzo-γ-pyranes (vitamin E), as well as derivatives of polyoxides (polyethylene glycol , polypropylene glycol, sorbitol), fatty acid esters (US patent No. 6482243, 2002)

The additive is used in motor fuels of the gasoline boiling range in the amount of 1 part per 500-1500 parts of fuel.

The disadvantages of this additive are:

the complexity of the composition;

energy-chemical instability during storage due to the presence of components such as vitamins A (retinol) and E (tocopherol);

complicated process for the synthesis of molecular structures of these vitamins.

The objective of the invention was to expand the arsenal of highly effective, simple compositional additives for motor fuels of the gasoline boiling range, which provide an improvement in the combustion mode of hydrocarbons of various molecular structures and reduce the emission of CO and NO _x in exhaust gases.

To solve this problem, an additive for gasoline fuels containing a cyclic aromatic compound and oxygenates in the form of a mixture of C ₂ -C ₅ alcohols and dicarboxylic acid esters is proposed. According to the invention, 1,3-diphenylurea of the formula C ₆ H ₅ NHCONHC is used as a cyclic aromatic compound ₆ H ₅ , the additive additionally contains an ashless phenolic type antioxidant and a solvent in the form of a mixture of kerosene and gasoline in the following ratio, wt.%:

1,3-diphenylurea 17.7-22.4 alcohols C ₂ -C ₅ 20-22 ester dicarboxylic acid 0.1-0.3 antioxidants 0.02-0.05 solvent rest

According to the invention, adipic acid esters, adipic acid dibutyl ester, phthalic acid dibutyl ester, sebacic acid dioctyl ester, azelaic dioctyl ester, dibutyl phthalate or a mixture thereof are used as dicarboxylic acid esters.

According to the invention, dibutyl ether of phthalic acid or dioctyl ether of sebacic acid and / or dioctyl ether of azelaic acid or mixtures thereof are used as dicarboxylic acid esters.

According to the invention, 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, β- (3,5-di-tert-butyl-4 ester are used as phenolic ashless type oxidants). -oxyphenyl) -propionic acid with octadecanol or 1,6-hexanediol.

According to the invention, 2,6-di-tert-butyl-4-methylphenol is used as phenolic ashless type.

According to the invention, a mixture of kerosene and gasoline is used at a ratio of (0.5-1) :( 1.0-2.0) (including).

When using additives in motor fuels of the gasoline boiling range, the combustion of fuel-air charges in the combustion chambers of carburetor and injection engines is improved and the emission of CO, NO _x gases is reduced, which is explained by:

the presence in the molecule of 1,3-diphenylurea (C ₆ H ₅ NHCONHC ₆ H ₅ ) a large number of π-electrons bonded into a single conjugated system. These electrons have great mobility, therefore, the DFM molecule tends to be strongly polarized when approaching the charged particles (ions) of the flame plasma, charging like an electric capacitor. Plasma ions condensed around polarized molecules increase the energy of the combustion plasma;

the tendency of the molecular structure of 1,3-diphenylurea (C ₆ H ₅ NHCONHC ₆ H ₅ ) at elevated temperatures to reduce nitrogen oxides to pure nitrogen;

to facilitate the combustion of fuel hydrocarbons to non-toxic CO ₂ due to the stability of the temperature field in the combustion chamber.

The presence of antioxidants in the composition, as well as the use of a solvent in the form of a mixture of liquid hydrocarbons kerosene and gasoline for the preparation of the additive, ensures the stability of the chemical-physical properties of the additive for a long period of time.

The additive composition proposed by the claimed technical solution is selected from the group of simple and accessible chemical compounds. The additive improves the combustion regime of liquid hydrocarbons of various molecular structures, provides for the completeness of their combustion, which reduces the specific cost of motor fuel, lowers emissions of CO and NO _x , reduces gum formation, and reduces wear on the piston and cylinder group.

In the analysis of the prior art, no additives were found for motor fuels of the gasoline boiling range with a combination of features corresponding to the claimed technical solution and implementing the above-described technical result, which is confirmed below by the description of the invention.

The essence of the invention is illustrated by recommendations regarding the choice of raw materials, examples of specific compositions of composite additives, recommendations for their practical application and test results.

Ready-to-use raw materials are used for the manufacture of specific compositions of additive compositions for gasoline boiling range fuels used in carburetor and injection internal combustion engines.

For specific additive compositions according to the invention use

1,3-diphenylurea (C ₆ H ₅ NHCONHC ₆ H ₅ ), m.v. - 212.25, T _bales. - 262 ° С (Catalog Handbook of Fine Chemicals Aldrich, 1992-1993, 250 p.);

iso-propyl alcohol, sec-butyl alcohol;

dicarboxylic acid esters - phthalic acid dibutyl ester (C ₆ H ₄ (COOC ₄ H ₉ ) ₂ , sebacic acid dioctyl ester ((CH ₂ ) ₈ (COOC ₈ H ₁₇ ) ₂ ). Named dicarboxylic acid esters in the preparation of additive compositions selected in a ratio of 1: 1;

Phenolic-type ashless antioxidant -2,6-di-tert-butyl-4-methylphenol. Trademark "Agidol" -TU 385901237-90;

kerosene -TU-3840158-10-90. Perhaps the use of kerosene TS-1-GOST 10227-86;

retinol and tocopherol vitamins;

gasolines of the AI-92 trademark.

From the used raw materials within the prescribed formulations by the method of mixing at room temperature, prepared additive compositions were prepared for 500 ml per the following examples:

Example 1 - additive according to the invention:

1,3-diphenylurea - 90 g, isopropyl and sec-butyl alcohols in a ratio of 1: 1 - 100 ml, a mixture of dicarboxylic acid esters (phthalic acid dibutyl ester, sebacic acid dioctyl ester in a ratio of 1: 1 (parts by weight) - 1 ml, 2,6-di-tert-butyl-4-methylphenol - 0.15 ml, kerosene 100 ml, gasoline AI-92 - the rest.

Example 2 - additive with the composition of the components according to US patent No. 6482243:

retinol and tocopherol at a ratio of 1: 1 (v / h) - 50 ml; isopropyl and sec-butyl alcohols in a ratio of 1: 1, the specified mixture of esters of dicarboxylic acids at a ratio of 1: 1 (v / v) - 450 ml.

Example 3 - automobile gasoline AI-92.

To study the effect of additive compositions on the operation of the internal combustion engine, the additives indicated in Examples 1 and 2 were added in the amount of 0.2 wt.% To AI-92 motor gasoline. The specified norm for the use of additives in finished gasoline fuels complies with well-known recommendations.

In studying the influence of the additives described in examples 1 and 2 on the operation of the internal combustion engine, the following methods were used.

1. One of the engine cylinders (4-cylinder, with distributed fuel injection, volume 2000 cm ³ , compression ratio 9.8) was equipped with a specially developed spark plug with a piezoelectric sensor, which allows converting pressure fluctuations in the cylinder into an electrical signal, which the digital form was processed by discrete conversion and dynamic spectral analysis, which allows you to track the appearance and attenuation of frequency components with a maximum frequency resolution of 1 Hz.

2. Measurement of the content of carbon monoxide (CO), hydrocarbons (CH) and nitrogen oxides (NO _x ) in the exhaust gas (OG). The measurements were carried out on cars "Niva" and "Toyota Vista" (distributed fuel injection). The content of CO and CH was determined using a portable gas analyzer, the content of NO _{x was} determined by the iodometric method from a solution of potassium iodide, through which a certain volume of exhaust gases was passed. Measurements were carried out at various engine operating modes.

3. Road tests were carried out on Niva, Toyota Vista, VAZ-2106, UAZ-469, GAZ-53, Volga GAZ-24 cars.

Based on the data obtained during the acoustic analysis of the processes in the engine cylinder by the transit time of echoes reflected from the piston, as well as data on the values of the temperature of the exhaust gases at the time of release, the values of sound velocities at various moments of the compression-expansion cycle were calculated, which were used to determine pressure values in the cylinder at various operating modes. As can be seen from the diagram below 1 (see figure 1):

when using an additive (example 1) in gasoline, the useful work of expanding gas (curve 1) at the same fuel consumption increases (the area limited by the pressure curve 4-stage compression and curve 1-stage expansion) by about 25%;

when using the additive (example 2), these indicators (curve 2) practically correspond to the use of commercial gasoline in the internal combustion engine (curve 3).

Changes in torque in internal combustion engines (diagram 2, figure 2) are similar in terms of the values obtained.

The results obtained in diagrams 1-2, have a similar tendency when the ratio of raw materials for the inventive additive is changed within a given formulation (wt.%).

A decrease in the composition of 1,3-diphenylurea leads to a decrease in the obtained technical indicators in charts 1-2. An increase in the additive formulation of the compound does not have a significant effect on the thermal process of the engine.

In view of these circumstances, the expediency of using the inventive additive in motor gasoline was established within the known recommendations, but in a concentration of not more than 1%.

A decrease or increase in the additive formulation of a given ratio of aliphatic alcohols, dicarboxylic acid esters can lead, on the one hand, to a decrease in the detonation resistance of fuels, and, on the other hand, to an increase in the emission of nitrogen oxides.

The decrease in the additive formulation of a given amount of antioxidant affects the thermochemical stability of the composition when used in the latter specified solvents. An increase in antioxidants increases the cost of the additive.

The use of a solvent for the preparation of additives based on a mixture of liquid hydrocarbons, respectively, of kerosene and gasoline is most optimal for the technological compatibility of the additive composition with motor gasolines. The ratio between kerosene and gasolines indicated by the invention meets, on the one hand, fire safety requirements, and, on the other hand, is most optimal for the conditions of use of the additive in commercial gasolines

Studies have also confirmed that the chemical and physical properties of the additive in relation to marketable gasolines are stable for a long period (over 3 months). Tests of the additive containing retinol and tocopherol after 20 days of storage of this additive showed that the technical performance when using gasoline with this additive corresponds to the performance of commercial gasoline without this additive.

The occurrence resulting from the use of the additive according to the invention is explained by the following:

At the initial stage of combustion, the process proceeds according to a branched chain mechanism until the temperature in the cylinder reaches a critical value at which gas ionization begins, accompanied by energy consumption and some stabilization of temperature and pressure (points 4.1, 4.2, 4.3 - diagram 1).

In the presence of an additive (example 1), the ions of the gas components formed during the ignition of hydrocarbons are concentrated around polarized diphenylurea molecules, which shifts the equilibrium and facilitates further ionization of the gas. A significant proportion of the energy released during combustion goes into the potential energy of the bound charges. As the cylinder pressure decreases (curve 1) when the piston does the work (expansion section), the stored energy is released, while the pressure on the piston decreases less sharply, the efficiency and torque increase (curve 1.1 - diagram 2).

Since the combustion of fuel occurs in a very short period of time, the bulk of the additive molecules, which have significant chemical resistance, do not have time to break down even at such high temperatures, the additive burns out later. This fact is also confirmed by the fact that in the presence of an additive (example 1), the pressure jump at the moment of combustion development decreases less sharply, which was revealed when playing unprocessed audio files recorded directly from the sensor, while slowing down the playback speed by 32-64 times.

Another feature of the additive according to the invention (example 1) is its ability to react with nitrogen oxides with the formation of molecular nitrogen, water and carbon dioxide.

The argument in favor of the idea of the participation of the additive in the combustion processes in molecular form is a sharp decrease in the concentration of nitrogen oxides in the exhaust gases when the additive is added to the fuel.

So, when the engine of the Toyota Vista car is without load at a crankshaft speed of 1000 rpm, the addition of an additive (example 1) to gasoline at a concentration of 0.2% leads to a drop in the NO _x content from 0.4 mg / m ³ to a value less than the detection limit (0.01 mg / m ³ ). The content of carbon monoxide (CO) and hydrocarbons (CH) is also reduced. The degree of this reduction depends on the engine operating mode and reaches a 6-fold value for CO and a 14-fold value for CH at 2000 rpm without load (Toyota Vista without a catalytic afterburner filter).

Road tests on various cars, various gasolines in the summer, autumn and winter periods when driving around the city and on the highway allow us to draw the following conclusions:

when examining parts and assemblies of engines that have accumulated more than 5,000 km with an additive according to the invention, there are no signs of a negative effect, no additives have been detected on the engine;

when using the additive according to the invention, the sensitivity of the engine to a change in the ignition timing is reduced. This allows you to switch to a lower-quality gasoline without a significant reduction in power and increased consumption. When conducting road tests on Volga GAZ-24, Moskvich 412, GAZ-53, UAZ-469 cars with straight-run gas gasoline (BGS, octane number-65 by the motor method), there were no significant differences between the BGS and the additive from marketable gasoline AI-80. Tests of BGS with an additive on a VAZ-2106 car were also carried out. In this case, the installation of a later ignition eliminates detonation without a noticeable loss in power.

Claims (6)

1. Additive for gasoline fuels containing a cyclic aromatic compound and oxygenates in the form of a mixture of C ₂ -C ₅ alcohols and dicarboxylic acid esters, characterized in that 1,3-diphenylurea of the formula C ₆ H ₅ NHCONHC _{6 is} used as a cyclic aromatic compound H ₅ , the additive additionally contains an ashless phenolic type antioxidant and a solvent in the form of a mixture of kerosene and gasoline in the following ratio, wt.%: 1,3-diphenylurea 17.7-22.4 Alcohols C ₂ -C ₅ 20-22 Ester dicarboxylic acid 0.1-0.3 Antioxidants 0.02-0.05 Solvent Rest 2. The additive according to claim 1, characterized in that the esters of dicarboxylic acids contain adipic acid esters, adipic acid dibutyl ester, phthalic acid dibutyl ester, sebacic acid dioctyl ester, azelaic acid dioctyl ester, dibutyl phthalate or a mixture thereof. 3. The additive according to claim 2, characterized in that, as dicarboxylic acid esters, it contains phthalic acid dibutyl ester or sebacic acid dioctyl ester and / or azelaic acid dioctyl ester or a mixture thereof. 4. The additive according to claim 1, characterized in that it contains 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, β- ester (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid with octadecanol or 1,6-hexanediol. 5. The additive according to claim 4, characterized in that it contains 2,6-di-tert-butyl-4-methylphenol as ashless phenolic type atoxidants. 6. The additive according to claim 1, characterized in that it contains a mixture of kerosene and gasoline at a ratio of (0.5-1) :( 1.0-2.0) (including).

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