JP2007270039A - Gasoline composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasoline composition which can reduce particulate materials (PM), especially SOF (soluble organic fraction), in exhaust gases in lean burn combustion direct injection engines. <P>SOLUTION: This gasoline composition containing 5 to 15 vol.% of ethyl tertiary butyl ether and 80 to 250 mass ppm of a cleaner, and having an aromatic content of ≤45 vol.%, a benzene content of ≤1.0 vol.%, a sulfur content of ≤8 mass ppm and a distillation endpoint of ≤210°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gasoline composition, and more particularly, to a gasoline composition that can reduce the emission of particulate matter, particularly SOF (Solvable Organic Fraction), in a lean burn combustion type direct injection gasoline engine.

In recent years, environmental problems have attracted attention, and reduction of carbon dioxide (CO ₂ ) is strongly demanded particularly from the viewpoint of preventing global warming. As a method of reducing carbon dioxide emissions from automobiles, a direct-injection engine has been developed in which the combustion of a conventional gasoline engine car, which was stoichiometric combustion, has been changed to a lean-burn combustion type that emits less carbon dioxide. It was.
However, when ordinary gasoline is used in a lean burn combustion type direct injection engine, there is a drawback that the emission amount of particulate matter (PM) in the exhaust gas increases due to insufficient mixing of gasoline and air. Are known.

By the way, PM is generally made into Dry Soot (black smoke), Sulfate (component generated by oxidation of sulfur in fuel) and SOF (Solubilized Organic Fraction: organic soluble component mainly composed of unburned fuel and lubricating oil). It is divided. Among these, SOF is said to be a causative substance of nanoparticles (fine particles having a particle diameter of 50 nm or less) which are said to damage human health.
Accordingly, it is necessary to reduce the amount of PM (total PM) and also the amount of SOF.

On the other hand, in order to reduce carbon monoxide (CO) and unburned hydrocarbons (THC) in exhaust gas, it has been widely studied to add an oxygen-containing compound to gasoline, particularly ethyl tertiary butyl ether (ETBE). Is attracting attention. It is known that a fuel oil containing an oxygen-containing compound such as ETBE can reduce PM (see, for example, Patent Document 1).
However, in the known techniques including Patent Document 1, reduction of PM in a stoichiometric direct injection engine is a problem. However, a method of reducing PM in a lean burn direct injection engine, particularly SOF is reduced. How to do is not considered.
Therefore, it is desired to develop gasoline that can reduce PM, particularly SOF, in a lean-burn combustion direct injection engine.

JP 2005-54103 A

  The present invention has been made under such circumstances, and in a lean burn direct injection engine, particulate matter (PM) in exhaust gas, in particular, SOF (Soluble Organic Fraction) can be reduced. The object is to provide a gasoline composition.

  The present inventors have found that the purpose can be achieved by blending ethyl tertiary butyl ether (ETBE) with gasoline having a specific composition to obtain a gasoline composition having a specific composition. The present invention has been completed based on such findings.

That is, the present invention
(1) 5 to 15% by volume of ethyl tertiary butyl ether and 80 to 250 mass ppm of detergent, aromatic content is 45% by volume or less, benzene content is 1.0% by volume or less, and sulfur content is 8% by mass a gasoline composition having a ppm or lower and a distillation end point of 210 ° C. or lower;
(2) The aromatic content having 10 or more carbon atoms is 2.0% by volume or less, and the total of the paraffin content and olefin content having 10 or more carbon atoms is 2.0% by volume or less. Gasoline composition,
(3) The gasoline composition according to the above (1) or (2), wherein a reformed gasoline having a distillation end point of 200 ° C. or less is blended in a range of 60% by volume or less based on the composition,
(4) The gasoline composition according to any one of (1) to (3), wherein cracked gasoline having a distillation end point of 210 ° C. or less is blended in a range of 60% by volume or less based on the composition.
(5) The gasoline composition according to any one of (1) to (4), wherein the gasoline composition is for a lean-burn combustion direct injection gasoline engine.
Is to provide.

  The gasoline composition of the present invention can reduce particulate matter (PM) in exhaust gas, particularly SOF (Soluble Organic Fraction), in a lean-burn combustion direct injection engine.

The gasoline composition of the present invention is required to contain 5% by volume or more, preferably 6% by volume or more of ethyl tertiary butyl ether (hereinafter sometimes referred to as “ETBE”). When the content of ETBE is 5% by volume or more, there is an effect of suppressing generation of PM in exhaust gas, particularly SOF, and reducing carbon monoxide and unburned hydrocarbons. On the other hand, the upper limit of the ETBE content needs to be 15% by volume or less, preferably 12% by volume or less. When the content of ETBE is 15% by volume or less, it is possible to maintain good driving performance without difficulty in controlling the air-fuel ratio of the engine.
The content of ETBE is a value measured by an all-component test method using a gas chromatograph in JIS K 2536-2 “Petroleum product-component test method”.

There is no restriction | limiting in particular about the manufacturing method of ETBE used by this invention, Even if it is ETBE obtained by what kind of manufacturing method, it can be used. For example, a method of reacting isobutylene and ethanol can be mentioned. In this case, ethanol as a raw material may be obtained from a known production method, but carbon dioxide (ethanol produced from biomass such as sugarcane and corn fermentation) is considered to be carbon dioxide from the concept of carbon neutral ( CO ₂ ) is preferable in terms of countermeasures.

The gasoline composition of the present invention is required to contain a detergent in an amount of 80 to 250 ppm by mass, preferably 100 to 200 ppm by mass. By containing 80 mass ppm or more of the cleaning agent, the cleaning effect is exhibited and the cleanliness of the nozzle in the engine combustion chamber is maintained. If the cleaning agent is 250 ppm by mass or less, there is no possibility that the discharge amount of PM or SOF will increase extremely.
As the detergent here, for example, compounds known as gasoline detergents such as succinimide, polyalkyl or polyalkenylamine, and polyetheramine can be used. Among these, polyetheramine is particularly preferable from the viewpoint of cleanliness effect.

  The gasoline composition of the present invention has an aromatic content of 45% by volume or less, preferably 35% by volume or less, more preferably 25% by volume or less. If the aromatic content is 45% by volume or less, there is no fear that carbon monoxide and unburned hydrocarbons in the exhaust gas will increase, and there is no fear that the spark plug will smolder, and the operating performance can be kept good. On the other hand, the lower limit of the aromatic content is not particularly limited, but it is preferably 5% by volume or more from the viewpoint of deterioration of fuel consumption and prevention of reduction in driving performance. The aromatic content is a value measured by an all-component test method using a gas chromatograph in JIS K 2536-2 “Petroleum products—Component test method”.

The gasoline composition of the present invention requires a benzene content of 1.0% by volume or less, preferably 0.5% by volume or less. If benzene is 1.0 volume% or less, benzene content in exhaust gas will decrease and there is no possibility that environmental pollution will become a problem. In addition, there is no risk that gasoline itself will adversely affect the human body.
In addition, benzene content is the value measured by the all-component test method by the gas chromatograph of JISK2536-2 "Petroleum product-component test method".

The gasoline composition of the present invention has a sulfur content of 8 mass ppm or less, preferably 5 mass ppm or less, more preferably 3 mass ppm or less. If the sulfur content is 8 mass ppm or less, the generation of PM can be suppressed, and the durability of the catalyst does not deteriorate.
The sulfur content is a value measured according to JIS K 2541-2 “Crude oil and petroleum products—sulfur content test method”.

  The gasoline composition of the present invention requires that the distillation end point is 210 ° C. or lower, preferably 200 ° C. or lower, more preferably 190 ° C. or lower. If the distillation end point is 210 ° C. or lower, it is possible to suppress a significant increase in the amount of PM or SOF generated in the exhaust gas. The end point of distillation referred to here is determined by the gas chromatographic method of JIS K 2254 “Petroleum products—Distillation test method”.

The gasoline composition of the present invention preferably has an aromatic content of 10 or more carbon atoms (hereinafter sometimes referred to as “C10 ⁺ A”) of 2.0% by volume or less, and 1.5% by volume or less. More preferably, it is particularly preferably 1.0% by volume or less. If C10 ⁺ A is 2.0% by volume or less, an increase in the amount of PM or SOF generated in the exhaust gas can be suppressed.
Furthermore, the gasoline composition of the present invention may be referred to as a paraffin component having 10 or more carbon atoms (hereinafter sometimes referred to as “C10 ⁺ P”) and an olefin component having 10 or more carbon atoms (hereinafter referred to as “C10 ⁺ O”). The total (C10 ⁺ P + C10 ⁺ O) is preferably 2.0% by volume or less, more preferably 1.5% by volume or less, and particularly preferably 1.0% by volume or less. preferable. When C10 ⁺ P + C10 ⁺ O is 2.0% by volume or less, an increase in the generation amount of PM or SOF in the exhaust gas can be suppressed.
C10 ⁺ A, C10 ⁺ P, and C10 ⁺ O are values measured by the all-component test method using a gas chromatograph of JIS K 25536-2 “Petroleum product-component test method”.

The gasoline composition of the present invention preferably has an olefin content (total olefin content) of 30% by volume or less, and more preferably 25% by volume or less. If the olefin content is 30% by volume or less, nitrogen oxides in the exhaust gas will not increase, and gasoline evaporated in the atmosphere will not generate ozone. Furthermore, there is no fear that the oxidation stability of gasoline itself will deteriorate. The lower limit of the olefin content is preferably 3% by volume. If the lower limit of the olefin content is 3% by volume or more, there is no risk of misfire in a lean combustion state, and the driving performance of the direct injection engine vehicle can be ensured.
The olefin content is a value measured by an all-component test method using a gas chromatograph in JIS K 2536-2 “Petroleum product-component test method”.

Furthermore, the gasoline composition of the present invention preferably has a density at 15 ° C. of 0.730 to 0.770 g / cm ³ , more preferably 0.740 to 0.760 g / cm ³ . If the density at 15 ° C. is 0.730 g / cm ³ or more, there is no fear of causing a decrease in engine output or fuel consumption, and if the density at 15 ° C. is 0.770 g / cm ³ or less, PM or SOF is reduced. The effect of reducing is sufficiently obtained.
The density at 15 ° C. here is a value measured according to JIS K 2249 “Crude oil and petroleum products—Density test method and density / mass / capacity conversion table”.

  Furthermore, the gasoline composition of the present invention preferably has a research octane number (RON) of 89 or more, more preferably 90 or more. If the RON is 89 or more, there is no possibility that the driving performance is deteriorated such as knocking. However, in the premium specification (JIS No. 1 gasoline), 96 or more is preferable. On the other hand, the upper limit of RON is not particularly limited, but is usually about 105. The octane number of the research method is a value measured by JIS K 2280 “Petroleum products—fuel oil—octane number and cetane number test method and cetane index calculation method”.

The gasoline composition of the present invention preferably further has the following distillation properties. In addition, the inside of () shows a more preferable range.
50% distillation temperature (T50): 75-100 ° C (80-95 ° C)
70% distillation temperature (T70): 100 to 125 ° C (105 to 120 ° C)
90% distillation temperature (T90): 140-165 ° C (145-160 ° C)
If T50, T70, and T90 are in the above ranges, the driving performance such as acceleration is kept good, and the fuel efficiency is not deteriorated.
The above T50, T70 and T90 are values obtained from the distillation properties measured based on the gas chromatographic method of JIS K 2254 “Petroleum products-distillation test method”.

  The gasoline composition of the present invention can be produced by any method. For example, it can prepare using the gasoline base material shown next with ETBE. As the gasoline base, for example, light naphtha obtained by atmospheric distillation of crude oil, cracked gasoline obtained by catalytic cracking or hydrocracking, reformed gasoline obtained by catalytic reforming, particularly reformed gasoline Fraction from which benzene is removed (debenzene-modified gasoline), polymerized gasoline obtained by olefin polymerization, alkylate obtained by adding lower olefin to hydrocarbon such as isobutane, linear lower paraffinic hydrocarbon Isomerized gasoline (isomerate), de-n-paraffin oil obtained by isomerization, and a specific range of fractions and aromatic hydrocarbons.

Preferred examples of the composition of the gasoline composition of the present invention include the following.
(1) Debenzene-modified gasoline 0-60% by volume (10-60% by volume)
(2) Cracked gasoline 0-60% by volume (10-60% by volume)
(3) Light cracked gasoline 0-55 vol% (0-60 vol%)
(4) Alkylate 0-60% by volume (0-30% by volume)
(5) Desulfurized light naphtha 0-30% by volume (0-20% by volume)
(6) Butane, LPG 0-15% by volume (0-10% by volume)
(7) ETBE 5-15% by volume (6-12% by volume)
Regarding the distillation properties of the debenzene-modified gasoline of (1) above, the distillation end point (EP) is preferably 200 ° C. or less, more preferably 190 ° C. or less, in terms of suppressing the generation amount of PM and SOF. preferable.
Moreover, also about the distillation property of cracked gasoline of said (2), for the same reason, it is preferable that EP is 210 degrees C or less, and it is more preferable that it is 200 degrees C or less.

  Various additives can be appropriately blended in the gasoline composition of the present invention as necessary. Such additives include phenolic and amine antioxidants, metal deactivators such as Schiff compounds and thioamide compounds, surface ignition inhibitors such as organophosphorus compounds, polyhydric alcohols and ethers. Anti-icing agents, organic acid alkali metal and alkaline earth metal salts, auxiliary alcohols such as sulfates of higher alcohols, anionic surfactants, cationic surfactants, antistatic agents such as double-sided surfactants, alkenyl succinic acid Well-known gasoline additives such as rust inhibitors such as esters, identifiers such as kirizanine and coumarin, odorants such as natural essential oils and synthetic fragrances, and colorants such as azo dyes are listed. One of these additives Or 2 or more types can be added. Further, the additive amount of these additives may be appropriately selected depending on the situation, but it is usually preferable that the total amount of the additive is 0.1% by mass or less based on the gasoline composition.

EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not restrict | limited at all by these examples. The properties and performance of the gasoline composition were determined according to the following method.
[Properties of gasoline composition]
・ Research method octane number,
Measurement was performed according to JIS K 2280.
-Sulfur content Measured according to JIS K 2541-2.
-Aromatic content, olefin content, benzene, aromatic content having 10 or more carbon atoms, paraffin content having 10 or more carbon atoms, olefin content having 10 or more carbon atoms, and these were measured according to JIS K 2536-2.
Distillation property: Measured according to JIS K 2254 (gas chromatographic method).
-Density Measured according to JIS K 2249.

[Measurement of PM and SOF]
In accordance with “Technical Standard for Diesel Vehicle 10/15 Mode Exhaust Gas Measurement” (technical standard related to safety standards for road transport vehicles), the measurement was performed by the following method.
(1) PM generation and use vehicle: Toyota Motor Corporation Mark II (2003 direct injection lean burn vehicle)
・ Operation mode: 10.15 mode ・ Experiment temperature: 25 ℃
・ Experimental humidity: 50%
(2) PM collection A dilution device was connected to the exhaust pipe of the vehicle, and generated PM was collected by a collection filter.
・ Dilution device: Micro tunnel (MDLT-1300T type) manufactured by HORIBA, Ltd.
-Dilution rate: 20 times-Collection filter: QR-100 (diameter 700 mm) manufactured by Toyo Roshi Kaisha, Ltd.
(3) Measurement method of PM and SOF-The mass increase amount of the collection filter after PM collection was defined as the PM collection amount (mg). Moreover, the collection filter after PM collection was subjected to Soxhlet extraction with dichloromethane, and the mass of the extracted portion was defined as the SOF capture amount (mg).

Examples 1-5 and Comparative Examples 1-3
A gasoline composition (JIS No. 1 gasoline) was prepared using the gasoline base material shown in Table 1 and mixed at the ratio shown in Table 2, and its properties, composition and performance are shown in Table 2.
In Table 2, ETBE is ethyl tertiary butyl ether, and the detergent is polyetheramine.

Examples 6 to 10 and Comparative Examples 4 to 6
A gasoline composition (JIS No. 2 gasoline) is prepared using the gasoline base material shown in Table 3 and mixed at the ratio shown in Table 4. The properties, composition and performance are shown in Table 2.
The ETBE and the detergent in Table 4 are the same as the compounds shown in Table 2.

  From Tables 1 to 4, the gasolines of Examples 1 to 10 all have a small amount of PM and SOF generated. On the other hand, Comparative Example 1 containing no ETBE and containing a large amount of aromatics, Comparative Example 4 containing no ETBE, Comparative Example 2 containing a large amount of aromatics, Comparative Examples 3 and 6 containing a large amount of detergent, and a distillation end point It can be seen that Comparative Example 5 having a high A generates a large amount of PM and SOF.

According to the gasoline composition of the present invention, it is possible to obtain a gasoline composition that can reduce particulate matter (PM) in exhaust gas, in particular, SOF, even in a lean burn direct injection engine. Further, since the gasoline composition of the present invention contains a certain amount or more of ETBE, it can reduce carbon monoxide (CO) and unburned hydrocarbons (THC) in the exhaust gas, and can be used for a lean burn direct injection engine. Carbon dioxide (CO ₂ ) can also be reduced. Therefore, it is useful as gasoline that can prevent environmental pollution and global warming.

Claims (5)

  5 to 15% by volume of ethyl tertiary butyl ether and 80 to 250 mass ppm of detergent, aromatic content is 45% by volume or less, benzene content is 1.0% by volume or less, sulfur content is 8% by mass or less, And the gasoline composition whose distillation end point is 210 degrees C or less.   The gasoline composition according to claim 1, wherein the aromatic content having 10 or more carbon atoms is 2.0% by volume or less, and the total of the paraffin content and olefin content having 10 or more carbon atoms is 2.0% by volume or less.   The gasoline composition according to claim 1 or 2, wherein reformed gasoline having a distillation end point of 200 ° C or less is blended in a range of 60% by volume or less based on the composition.   The gasoline composition according to any one of claims 1 to 3, wherein cracked gasoline having a distillation end point of 210 ° C or less is blended in a range of 60% by volume or less based on the composition.   The gasoline composition according to any one of claims 1 to 4, which is used for a lean-burn combustion direct injection gasoline engine.