JPH10121064A - Unleaded gasoline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an unleaded gasoline improved in lean combustibility and oxidation stability by incorporating specified amounts of two olefins in gasoline. SOLUTION: This gasoline contains 3-20vol.% 6 C or lower linear, branched or cyclic olefin such as 1-pentene, 1-hexene, 2-methyl-1-butene or 3,3'-dimethyl-1- butene and 0.1-9vol.% 7 C or higher linear, branched or cyclic olefin such as 2,2,3-trimethyl-1-butene, 4,4-dimethyl-1-pentene, 1-decene, 2-methyl-3-ethyl-1-pentene or 1-octene. The olefin component is used desirably in an amount corresponding to a diene value, which is a measure of a diene component, of 3.6 or below. The sulfur content is 50ppm wt. or below at which an increase in an NOx level is not brought about. The benzene content is 1vol.% or below so as to prevent it from being discharged into atmospheric air. The gasoline should have a 30vol.% evaporation temperature of 50-75 deg.C and a Research Octane Number(RON) of 89 or above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel unleaded gasoline, and more particularly, to an unleaded gasoline suitable for a lean burn gasoline engine.

[0002]

2. Description of the Related Art As one method for improving the fuel efficiency of a gasoline engine, a lean burn system (lean burn, direct injection, etc.) is known. Here, the lean burn engine refers to an engine operated at an air-fuel ratio (for example, 20 to 23) larger than the stoichiometric air-fuel ratio (14 to 15), and the direct injection engine is an engine in which fuel is directly injected into a cylinder. Say. In short, this combustion method increases the air-fuel ratio,
That is, this is a method of improving fuel efficiency by making the gasoline mixture lean. However, the problems that occur during lean burn are:
And the torque variation is likely to occur, in the conventional three-way catalyst is an exhaust gas purifying catalyst is that the purification ratio of NO _X (nitrogen oxides) is reduced. Therefore, lean in burn gasoline engine, and expand the lean burn limit by improving the combustion, i.e., at less possible to torque fluctuations of the combustion in the leaner air-fuel mixture, necessary to achieve a NO _X reduction It is. Generally, it is known that the combustion rate of gasoline should be increased in order to improve the flammability.
To this end, it is conceivable to lighten gasoline or increase the proportion of olefins having a higher burning rate than paraffins and aroma fractions. For example, Tech Pa
p FISISTA Cngr, Vol. 23rd, N
o. Vol 1, PAGE 311-316 (199
0) states that in a gasoline engine, a fuel having a higher combustion rate has a higher lean burn limit.
Fuels, lubrication, and lubricating oils (Sankaido) show that olefins have higher combustion rates than paraffins and aromas, and that increasing the proportion of olefins can increase the lean burn limit. I can affirm it. However, when the olefin content increases, there is a problem that the oxidation stability of the fuel is reduced.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a lead-free gasoline excellent in lean burnability and oxidation stability.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that gasoline having a specific olefin content in a specific content range achieves the above object. The present invention has been completed based on such findings. That is, the gist of the present invention is as follows. (1) The content of the olefin having 6 or less carbon atoms is 3 to 20.
An unleaded gasoline having an octane value of 89 or more, characterized in that the content of the olefin having 7 or more carbon atoms is 0.1 to 9% by volume. (2) The unleaded gasoline according to (1), wherein the sulfur content is 50 ppm by weight or less. (3) The unleaded gasoline according to (1) or (2), wherein the benzene content is 1% by volume or less. (4) 30% by volume distillation temperature is 50 to 75 ° C. (1)
The unleaded gasoline according to any one of (1) to (3). (5) The unleaded gasoline according to any one of (1) to (4), wherein the 50% by volume distillation temperature is 75 to 105 ° C.

[0005]

Embodiments of the present invention will be described below. In the unleaded gasoline of the present invention, the content of the olefin having 6 or less carbon atoms is 3 to 20% by volume, preferably 4 to 18% by volume, and more preferably 5 to 16% by volume. The olefin having 6 or less carbon atoms may be linear, branched, or cyclic; for example, 1-pentene; 2
-Pentene; 1-hexene; 2-hexene; 2-methyl-1-butene; 3-methyl-1-butene; 2-ethyl-
1-butene; 2-methyl-1-pentene; 4-methyl-
1-pentene; 2,3-dimethyl-1-butene; 1-butene; 3,3-dimethyl-1-butene and the like. 3% by volume of the above olefins having 6 or less carbon atoms
If it is less than 10%, lean burnability is poor, and if it exceeds 20% by volume, oxidation stability is poor.

The unleaded gasoline of the present invention has a carbon number of 7
The above olefin content is 0.1 to 9% by volume, preferably 0.1 to 7% by volume, and more preferably 0.1 to 6% by volume. The olefin having 7 or more carbon atoms may be linear, branched, or cyclic. For example, 2,2,3-trimethyl-1-butene; 2,2,3
-Trimethyl-2-butene; 4,4-dimethyl-1-pentene; 1-decene; 2,3-dimethyl-1-pentene; 4-ethyl-3-heptene; 2-methyl-3-ethyl-1-pentene 1-octene; 2,3-dimethyl-
3-hexene and the like can be mentioned. The above carbon number 7
When the olefin content is less than 0.1% by volume, lean burnability is poor, and when it exceeds 9% by volume, oxidation stability is poor.
Also, the diolefin component may be included because of its high burning rate, but if it is large, the oxidation stability is reduced,
It is desirable that the diene value, which is a measure of the amount of diene, be 3.6 or less. The content of the olefins having 6 or less carbon atoms and the olefins having 7 or more carbon atoms is determined by the Japan Petroleum Institute.
It is a value measured based on the gas chromatography method of JPI-5S-33-90.

[0007] The sulfur content in the unleaded gasoline of the present invention is preferably 50 ppm by weight or less, more preferably 20 ppm by weight or less. If more than 50 wt ppm, reduces the purifying ability of the three-way catalyst, there is a case where emission of the NO _X increases. The sulfur content referred to here is JI
This is a value measured by SK-2541. The benzene content in the unleaded gasoline of the present invention is preferably 1% by volume or less in order to prevent the emission of benzene suspected of causing carcinogen to the atmosphere. The benzene content here is a value measured based on the gas chromatography method of the Japan Petroleum Institute method JPI-5S-33-90.

The unleaded gasoline of the present invention has a content of 30% by volume.
Preferably, the distillation temperature is in the range from 50 to 75C. When the 30% by volume distillation temperature exceeds 75 ° C., the vaporization property is deteriorated, the mixing property between the fuel and the air becomes insufficient, and the startability and the operability may be deteriorated.
If the distillation temperature is lower than 50 ° C., there is a possibility that vapor lock (vaporization in the fuel line) occurs. The unleaded gasoline of the present invention has a 50% by volume distillation temperature of 75%.
It is preferably in the range of -105 ° C. This 50% by volume
If the distilling temperature exceeds 105 ° C., operability at low or intermediate temperatures may be impaired. If the 50% by volume distilling temperature is less than 75 ° C., vapor lock or icing in a carburetor car may occur. There are cases. The 30 and 50% by volume distillation temperature is a value measured according to JIS K-2254.

The unleaded gasoline of the present invention has a research octane number (RON) of 89 or more, and a motor octane number (MON) of 80 or more from the viewpoint of preventing a reduction in knock resistance during high-speed running. Is preferred. Here, RON and MON are values measured according to JIS K-2280. The unleaded gasoline of the present invention may be any one that satisfies the above conditions and satisfies the JIS standard. The base material is not particularly limited. For example, a light naphtha fraction obtained by atmospheric distillation of crude oil is desulfurized. Light naphtha (DLN) obtained by cracking, cracked gasoline (FG) obtained by fluid catalytic cracking, light cracked gasoline (LFG) consisting only of a light portion having a distillation property obtained by distillation of cracked gasoline, distillation of cracked gasoline Cracked gasoline (HFG) consisting only of a heavy portion having a distillation property obtained by the above method, reformed gasoline (PG) obtained by a catalytic reforming method, etc., and debenzene-reformed gasoline obtained by removing benzene from the reformed gasoline ( PGZ), polymerized gasoline obtained by polymerization of olefins, hydrocarbons such as isobutane, and lower olefins such as propylene and butene. Alkylated gasoline obtained by (alkylation), isopentane obtained by separating and removing n-paraffin from light naphtha, LPG by crude distillation of crude oil, or cracked gas fraction obtained by fluid catalytic cracking, etc. From butane, isobutylene and methanol, and oxygen-containing compounds such as tertiary amyl methyl ether (TAME), ethyl tertiary butyl ether (ETBE), and tertiary amyl ethyl ether (TAEE). It can be prepared by appropriately mixing so as to satisfy the conditions.

The fuel oil of the present invention may further contain various additives as required. Such additives include, for example, phenylenediamines,
Antioxidants such as diphenylamine, alkylphenol or aminophenol, detergents such as polyetheramine and polyalkylamine, metal deactivators such as Schiff-type compounds and thioamide-type compounds, and surface ignition such as organic phosphorus compounds Anti-freezing agents such as polyhydric alcohols and ethers, alkali metal salts and alkaline earth metal salts of organic acids, flame retardants such as sulfates of higher alcohols, anionic surfactants, cationic surfactants,
Known fuels such as antistatic agents such as amphoteric surfactants, rust inhibitors such as alkenyl succinic acid esters, discriminating agents such as chirizanine and coumarin, odorants such as natural essential oils and synthetic flavors, and coloring agents such as azo dyes Oil additives may be mentioned, and one or more of these may be added. Also,
The addition amount of these additives may be appropriately selected according to the situation, but it is usually desirable that the total amount of the additives be 0.1% by weight or less of the unleaded gasoline.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention thereto. The properties and performance of unleaded gasoline were determined by the following methods. (1) Density Measured according to JIS K-2249. (2) Vapor pressure Measured according to JIS K-2258. (3) Research method octane number, motor method octane number Measured according to JIS K-2280. (4) Distillation properties Measured according to JIS K-2254. (5) Component composition It was measured by a gas chromatography method according to the Japan Petroleum Institute method JPI-5S-33-90. (6) Sulfur content Measured according to JIS K-2541. (7) Oxidation stability Measured according to JIS K-2287.

Examples 1 to 3 and Comparative Examples 1 to 6 A base gasoline obtained by mixing each gasoline base material having the properties and compositions shown in Table 1 in the proportions shown in Table 2 was used as an antioxidant with Sumilizer 4ML (Sumitomo). Chemical Industry Co., Ltd.)
Was added in the proportions shown in Table 2 to obtain unleaded gasolines of Examples 1 to 3 and Comparative Examples 1 to 6. Table 2 shows the properties and composition of the obtained unleaded gasoline. Using these examples and comparative examples, the oxidation stability was measured, and the induction period was determined. Table 2 shows the results. The induction period is a measure of the tendency of gum formation during storage of motor gasoline, with longer oxidative stability. As is clear from Table 2, it can be seen that the example has a longer induction period and a higher oxidation stability at the same amount of the antioxidant as compared with the comparative example.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

[Table 3]

[0016]

[Table 4]

[0017]

[Table 5]

[0018]

The unleaded gasoline of the present invention is excellent in lean burnability and oxidation stability.

Claims (5)

[Claims] An olefin having 6 or less carbon atoms has a content of 3 to 20% by volume, and an olefin having 7 or more carbon atoms has a content of 0.1 to 9% by volume. Unleaded gasoline with a research octane number of 89 or more. 2. The unleaded gasoline according to claim 1, wherein the sulfur content is 50 ppm by weight or less. 3. The unleaded gasoline according to claim 1, wherein the benzene content is 1% by volume or less. 4. The unleaded gasoline according to claim 1, wherein the 30% by volume distillation temperature is 50 to 75 ° C. 5. The unleaded gasoline according to claim 1, wherein the 50% by volume distillation temperature is 75 to 105 ° C.