JP7300923B2 - Fuel composition for lean burn engine - Google Patents

Description

The present invention relates to fuel compositions for lean burn engines.

Conventionally, a lean-burn engine that burns fuel with an air-fuel mixture leaner than the stoichiometric air-fuel ratio is known. As a fuel for such a lean-burn engine, for example, in Patent Document 1, one or more gasolines selected from the group consisting of alkylate gasoline, catalytically reformed gasoline, light catalytically cracked gasoline, and coker light gasoline are blended. A lean burn engine fuel composition is disclosed.

JP 2007-182579 A

In a lean-burn engine, the upper limit of the operable air-fuel ratio (air/fuel) is called the lean limit, and by expanding the lean limit, it is expected to improve fuel efficiency, stabilize combustion, and the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel composition for a lean-burn engine that can extend the lean limit of the lean-burn engine.

One aspect of the present invention relates to a fuel composition for a lean-burn engine, which is mainly composed of hydrocarbons having 4 to 6 carbon atoms and has an aromatic content of 25% by volume or less.

In one aspect, the content of the olefin having 4 to 6 carbon atoms may be 20 to 60% by volume based on the total amount of the hydrocarbons having 4 to 6 carbon atoms.

In one aspect, the content of normal paraffins having 4 to 6 carbon atoms may be 20% by volume or less with respect to the total amount of hydrocarbons having 4 to 6 carbon atoms.

In one aspect, the content of the hydrocarbon having 4 to 6 carbon atoms may be 85% by volume or more.

According to the present invention, there is provided a fuel composition for lean-burn engines capable of extending the lean limit of lean-burn engines.

Preferred embodiments of the present invention are described in detail below.

The fuel composition according to the present embodiment is mainly composed of hydrocarbons having 4 to 6 carbon atoms (for example, 50% by volume or more, preferably 60% by volume or more, more preferably 70% by volume or more, and still more preferably 80% by volume or more. , more preferably 85% by volume or more).

In this embodiment, the aromatic content of the fuel composition is 25% by volume or less, preferably 20% by volume or less, more preferably 15% by volume or less, even more preferably 10% by volume or less, even more preferably 5% by volume. % or less, more preferably 3 volume % or less, particularly preferably 2 volume % or less.

The fuel composition according to the present embodiment is mainly composed of hydrocarbons having 4 to 6 carbon atoms, and the aromatic content is set to a certain value or less, so that the lean limit of the lean burn engine can be expanded. It can be suitably used as a fuel composition for lean-burn engines (in particular, for ultra-lean combustion with a lean limit of 2 or more).

In this specification, the content of each component in the fuel composition is measured by the method described in JIS K 2536-2 "Petroleum products - Component test method Part 2: Determination of all components by gas chromatography". value.

The aromatic content of the fuel composition may be, for example, 0.1% by volume or more, or may be 0.5% by volume or more. By containing a small amount of the aromatic compound, it is possible to obtain the effect of further increasing the calorific value per capacity while suppressing knocking.

Examples of hydrocarbons having 4 to 6 carbon atoms include normal paraffins having 4 to 6 carbon atoms, isoparaffins having 4 to 6 carbon atoms, olefins having 4 to 6 carbon atoms, aromatic compounds having 6 carbon atoms (benzene), and the like. may be included.

In the fuel composition according to the present embodiment, the content of normal paraffins having 4 to 6 carbon atoms may be, for example, 30% by volume or less, preferably 20% by volume, based on the total amount of hydrocarbons having 4 to 6 carbon atoms. % by volume or less, more preferably 15% by volume or less. As a result, the above effects tend to be obtained more remarkably.

In addition, the content of normal paraffins having 4 to 6 carbon atoms may be, for example, 0.5% by volume or more, or 1% by volume or more, relative to the total amount of hydrocarbons having 4 to 6 carbon atoms. , preferably 5% by volume or more, more preferably 10% by volume or more. As a result, the above effects tend to be obtained more remarkably.

In the fuel composition according to the present embodiment, the content of isoparaffins having 4 to 6 carbon atoms may be, for example, 20% by volume or more, preferably 25% by volume, relative to the total amount of hydrocarbons having 4 to 6 carbon atoms. % or more, more preferably 30 volume % or more, still more preferably 35 volume % or more. As a result, the above effects tend to be obtained more remarkably.

In addition, the content of isoparaffins having 4 to 6 carbon atoms may be, for example, 80% by volume or less, preferably 75% by volume or less, more preferably 70% by volume, relative to the total amount of hydrocarbons having 4 to 6 carbon atoms. % or less. Also, the content of isoparaffins having 4 to 6 carbon atoms may be 60% by volume or less, 50% by volume or less, or 45% by volume or less with respect to the total amount of hydrocarbons having 4 to 6 carbon atoms. As a result, the above effects tend to be obtained more remarkably.

In the fuel composition according to the present embodiment, the content of olefins having 4 to 6 carbon atoms may be, for example, 5% by volume or more, preferably 10% by volume, relative to the total amount of hydrocarbons having 4 to 6 carbon atoms. % or more, more preferably 20 volume % or more, and still more preferably 25 volume % or more. In addition, the content of olefins having 4 to 6 carbon atoms may be 30% by volume or more, 35% by volume or more, or 40% by volume or more with respect to the total amount of hydrocarbons having 4 to 6 carbon atoms. As a result, the above effects tend to be obtained more remarkably.

In addition, the content of olefins having 4 to 6 carbon atoms may be, for example, 70% by volume or less, preferably 65% by volume or less, more preferably 60% by volume, relative to the total amount of hydrocarbons having 4 to 6 carbon atoms. % or less, more preferably 55 volume % or less, even more preferably 50 volume % or less, and even more preferably 45 volume % or less. As a result, the above effects tend to be obtained more remarkably.

In the fuel composition according to the present embodiment, the total amount of normal paraffins having 4 to 6 carbon atoms, isoparaffins having 4 to 6 carbon atoms and olefins having 4 to 6 carbon atoms is the total amount of hydrocarbons having 4 to 6 carbon atoms. On the other hand, for example, it is 50% by volume or more, preferably 70% by volume or more, more preferably 80% by volume or more, still more preferably 90% by volume or more, and still more preferably 93% by volume or more. As a result, the above effects tend to be obtained more remarkably.

The fuel composition according to this embodiment may contain hydrocarbons having more than 6 carbon atoms. Hydrocarbons with more than 6 carbon atoms may be, for example, hydrocarbons with 7 to 15 carbon atoms, or may be hydrocarbons with 7 to 10 carbon atoms.

In the fuel composition according to the present embodiment, the content of hydrocarbons having more than 6 carbon atoms may be, for example, less than 50% by volume, preferably 40% by volume or less, more preferably 40% by volume or less, relative to the total amount of the fuel composition. is 30% by volume or less, more preferably 20% by volume or less, and even more preferably 15% by volume or less.

In the fuel composition according to the present embodiment, the proportion of hydrocarbons having 4 to 6 carbon atoms in the total amount of hydrocarbons is, for example, 50% by volume or more, more preferably 60% by volume or more, more preferably 70% by volume. Above, more preferably 80% by volume or more, still more preferably 85% by volume or more, and even more preferably 90% by mass or more. The proportion of hydrocarbons having 4 to 6 carbon atoms in the total amount of hydrocarbons may be 100% by volume or less, 98% by volume or less, or 95% by volume or less.

The fuel composition according to this embodiment may further contain an oxygen-containing compound.

An oxygen-containing compound is an organic compound containing oxygen as a constituent element. Examples of oxygen-containing compounds include oxygen-containing heterocyclic compounds, oxygen-containing aromatic compounds, and oxygen-containing aliphatic compounds. An oxygen-containing compound may be used individually by 1 type, and may be used in combination of 2 or more types.

An oxygen-containing heterocyclic compound is a compound having an oxygen-containing heterocycle. Oxygen-containing heterocyclic compounds include, for example, compounds having an oxygen-containing heterocyclic ring such as furan ring, tetrahydrofuran ring, ethylene oxide ring, propylene oxide ring, pyran ring, tetrahydropyran ring, benzofuran ring, and benzopyran ring. As the oxygen-containing heterocyclic compound, a compound having a furan ring is preferable from the viewpoint that the above effects can be obtained more remarkably. Examples of compounds having a furan ring include furan, 2-methylfuran, and 2,5-dimethylfuran. As the compound having a furan ring, furan and 2-methylfuran are particularly preferred.

An oxygen-containing aromatic compound is a compound containing oxygen as a constituent element and having an aromatic ring. Examples of oxygen-containing aromatic compounds include aromatic compounds having an oxygen atom directly bonded to an aromatic ring (eg, alkoxybenzene, phenols, etc.). Alkoxybenzenes include, for example, anisole, phenetole, propyloxybenzene, and the like. As the alkoxybenzene, anisole and phenetole are preferable from the viewpoint of the boiling point range.

Examples of oxygen-containing aliphatic compounds include alcohols and ethers (eg, ethyl alcohol, isobutyl alcohol, ETBE (ethyl-tert-butyl ether), etc.).

In the fuel composition according to the present embodiment, the content of the oxygen-containing compound may be, for example, less than 50% by volume, preferably 40% by volume or less, more preferably 30% by volume, relative to the total amount of the fuel composition. 25% by volume or less, more preferably 25% by volume or less.

Further, when the fuel composition according to the present embodiment contains an oxygen-containing compound, the content thereof may be, for example, 1% by volume or more, or 3% by volume or more, relative to the total amount of the fuel composition. may be 5% by volume or more, or 10% by volume or more.

The fuel composition according to this embodiment may further contain components other than those described above. Other components include, for example, detergent dispersants, antioxidants, metal deactivators, surface ignition inhibitors, anti-icing agents, combustion improvers, antistatic agents, coloring agents, rust inhibitors, water draining agents, identification agents, odorants, friction modifiers, and the like. The total content of these other components may be, for example, 1% by volume or less, preferably 0.5% by volume or less, and more preferably 0.1% by volume or less, relative to the total amount of the fuel composition. Also, the total content of the above other components may be, for example, 0.001% by volume or more, or may be 0.002% by volume or more, relative to the total amount of the fuel composition.

As the detergent-dispersant, commonly used detergent-dispersants can be used, for example, compounds known as gasoline detergent-dispersants such as succinimide, polyalkylamine and polyetheramine can be used. Antioxidants include, for example, N,N'-diisopropyl-p-phenylenediamine, N,N'-diisobutyl-p-phenylenediamine, 2,6-di-t-butyl-4-methylphenol, hindered phenol and the like. Examples of metal deactivators include amine carbonyl condensation compounds such as N,N'-disalicylidene-1,2-diaminopropane. Examples of surface ignition inhibitors include organophosphorus compounds. Anti-icing agents include, for example, polyhydric alcohols and ethers thereof. Examples of the combustion improver include alkali metal salts or alkaline earth metal salts of organic acids, higher alcohol sulfate esters, and the like. Antistatic agents include, for example, anionic surfactants, cationic surfactants, and amphoteric surfactants. Examples of coloring agents include azo dyes. Rust preventives include, for example, organic carboxylic acids or derivatives thereof, alkenyl succinate esters, and the like. Examples of water-removing agents include sorbitan esters and the like. Identification agents include, for example, quillzanine, coumarin, and the like. Odorants include, for example, natural essential oil synthetic fragrances and the like. Examples of friction modifiers include mixtures of higher carboxylic acid monoglycerides and higher carboxylic acid amide compounds.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
As a fuel composition, a fuel composition having a composition shown in Table 1 below was prepared. The composition of the fuel composition indicates the value measured according to JIS K 2536-2 "Petroleum products - Component test method Part 2: Determination of all components by gas chromatography". Using the prepared fuel composition, the lean limit was measured by the following method. Table 1 shows the results.

<Measurement of lean limit>
The lean limit was measured by changing the excess air ratio using the following test engine under the conditions of 2000 rpm, indicated mean effective pressure of 800 kPa, and minimum advanced ignition timing (MBT) that maximizes torque. The lean limit was defined as the excess air ratio at which the rate of change in indicated mean effective pressure exceeded 3%. The excess air ratio is obtained by dividing the air-fuel ratio of the air-fuel mixture at the time of the test by the theoretical air-fuel ratio of the fuel composition, and is the reciprocal of the equivalence ratio φ.
(test engine)
Engine: Single cylinder Displacement: 563cc
Injection method: Port injection type

(Examples 2 to 10 and Comparative Examples 1 to 3)
The lean limit was measured in the same manner as in Example 1 by changing the composition of the fuel composition to that shown in Table 1, Table 2 or Table 3. The results are shown in Table 1, Table 2 or Table 3. In Example 9, ethanol was used as the oxygen-containing compound, and in Example 10, 2-methylfuran was used as the oxygen-containing compound. Comparative Example 1 is an example using high-octane gasoline, and the oxygen content in Comparative Example 1 indicates the content of oxygen-containing compounds contained in the high-octane gasoline.

In the table, "saturated content" indicates the content (% by volume) of saturated hydrocarbons, and "unsaturated content" indicates the content (% by volume) of unsaturated hydrocarbons (excluding aromatic compounds), "Aromatic content" indicates the content (% by volume) of aromatic compounds, "Oxygen content" indicates the content (% by volume) of oxygen-containing compounds, and "Total" indicates saturated hydrocarbons and unsaturated hydrocarbons. , indicates the total content (% by volume) of aromatic compounds and oxygen-containing compounds.

In the table, "C4-C6 hydrocarbons" indicates the content (% by volume) of hydrocarbons having 4 to 6 carbon atoms in the fuel composition, and "n-paraffins" are those having 4 to 6 carbon atoms. Indicates the content (% by volume) of normal paraffins having 4 to 6 carbon atoms relative to the total amount of hydrocarbons, and "isoparaffin" is the content of isoparaffins having 4 to 6 carbon atoms relative to the total amount of hydrocarbons having 4 to 6 carbon atoms ( %), "Olefin" indicates the content (% by volume) of olefins with 4 to 6 carbon atoms with respect to the total amount of hydrocarbons with 4 to 6 carbon atoms, and "Subtotal" indicates the content of olefins with 4 to 6 carbon atoms The total content (% by volume) of normal paraffins having 4 to 6 carbon atoms, isoparaffins having 4 to 6 carbon atoms and olefins having 4 to 6 carbon atoms is shown with respect to the total amount of hydrocarbons.

Claims (6)

The main component is a hydrocarbon having 4 to 6 carbon atoms,
The aromatic content is 0.1 to 25 % by volume ,
The content of olefins having 4 to 6 carbon atoms is 5 to 70% by volume, and the content of normal paraffins having 4 to 6 carbon atoms is 0.5 to 30% by volume, based on the total amount of hydrocarbons having 4 to 6 carbon atoms. %, the content of isoparaffins having 4 to 6 carbon atoms is 20 to 80% by volume,
A fuel composition for a lean-burn engine , wherein the content of the hydrocarbon having 4 to 6 carbon atoms is 70% by volume or more . 2. The lean-burn engine fuel composition according to claim 1, wherein the content of the olefin having 4 to 6 carbon atoms is 20 to 60% by volume with respect to the total amount of the hydrocarbons having 4 to 6 carbon atoms. 3. The lean-burn engine fuel composition according to claim 1, wherein the content of isoparaffins having 4 to 6 carbon atoms is 25 to 75% by volume with respect to the total amount of hydrocarbons having 4 to 6 carbon atoms. The lean according to any one of claims 1 to 3, wherein the content of normal paraffins having 4 to 6 carbon atoms is 0.5 to 20 % by volume with respect to the total amount of hydrocarbons having 4 to 6 carbon atoms. A fuel composition for burn engines. The lean-burn engine according to any one of claims 1 to 4, wherein the content of normal paraffins having 4 to 6 carbon atoms is 1 to 20% by volume with respect to the total amount of hydrocarbons having 4 to 6 carbon atoms. fuel composition. The fuel composition for a lean-burn engine according to any one of claims 1 to 5 , wherein the content of the hydrocarbon having 4 to 6 carbon atoms is 85% by volume or more.