JP2000248287A - Low-vapor pressure lead-free gasoline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fuel oil for automobile having excellent vehicle practical performances such as low-temperature driving performances, normal-temperature driving performances, reducing volatilization of light hydrocarbon and contributing to improvement in air pollution. SOLUTION: This lead-free gasoline has >=50 kpa to <=72 kpa lead vapor pressure, 10 vol.% distillation temperature at <=60 deg.C, preferably 50 vol.% distillation temperature at <=100 deg.C and more preferably <=7 vol.% content of <=4C hydrocarbon and >=35 vol.% content of <=6C hydrocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to unleaded gasoline for gasoline engines, and more particularly to unleaded gasoline for gasoline engines that reduces the emission of environmental pollutants and is excellent in low-temperature startability, drivability, and oxidation stability. Things.

[0002]

2. Description of the Related Art In recent years, demands for improving the atmospheric environment have been increasing, and in particular, photochemical oxidants in urban areas have not been remarkably improved in the last few years. ing. In the photochemical oxidant, light hydrocarbons present in the atmosphere are the trigger substance, and the light hydrocarbons (hereinafter sometimes referred to as “HC”) are generated at the time of gasoline distribution / refueling and running of gasoline vehicles. It is said that gasoline volatilization at times accounts for a considerable proportion. This volatile,
In other words, the main measures for reducing the amount of HC emission include measures for equipment such as a steam recovery mechanism in a vehicle and a refueling machine. On the other hand, this HC emission can also be reduced by suppressing the volatility of gasoline itself. However, there is a concern that easy reduction of volatility may lead to deterioration of actual vehicle performance such as low-temperature startability and drivability, which is a major factor hindering measures from the gasoline side.

[0003]

SUMMARY OF THE INVENTION In view of such a background, the present invention reduces the emission of light hydrocarbons (HC) in various situations in which gasoline is used, and thus suppresses the generation of photochemical oxidants. Still another object of the present invention is to provide an unleaded gasoline for a gasoline engine which has satisfactory actual vehicle practical performance.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the Reid vapor pressure,
It has been found that gasoline having specific properties in the 10% by volume distillation temperature, the 50% by volume distillation temperature, and the hydrocarbon composition is a high-performance gasoline that can solve the problem. That is, gasoline having a Reid vapor pressure of 50 kPa or more and 72 kPa or less and a 10% by volume distillation temperature of 60 ° C. or less, preferably a 50% by volume distillation temperature of 100 ° C.
The following gasoline, more preferably gasoline having a hydrocarbon content of not more than 4 carbon atoms of 7% by volume or less and a hydrocarbon content of 6 or less carbon atoms of not less than 35% by volume, provides an atmosphere of light hydrocarbons. And at the same time, excellent vehicle performance can be obtained.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The low vapor pressure unleaded gasoline of the present invention is required to satisfy both conditions of (1) a lead vapor pressure of 50 kPa or more and 72 kpa or less, and (2) a 10% by volume distillation temperature of 60 ° C. or less. ) 50% by volume distilling temperature satisfies the condition of 100 ° C. or less, and more preferably (4) content of hydrocarbon having 4 or less carbon atoms is 7% by volume or less (5) carbonization of 6 or less carbon atoms It satisfies both of the two conditions that the hydrogen content is 35% by volume or more.

The reed vapor pressure referred to here is JIS K
2258 “Vapor pressure measured by the crude oil and fuel oil vapor pressure test method (Lead method)” (Lead vapor pressure, RV
P). By setting the vapor pressure to 72 kpa or less, preferably 60 kpa or less according to the present invention, loading gasoline trucks from gasoline shipping facilities such as refineries and oil depots, and storing tanks at gas stations (service stations) from gasoline trucks It is possible to suppress the emission of light hydrocarbons into the atmosphere during filling of fuel, storage of gasoline at gas stations, refueling of gasoline vehicles at gas stations, running of gasoline vehicles, parking of gasoline vehicles, and the like.

On the other hand, by setting the vapor pressure to 50 kpa or more, it is possible to form an air-fuel mixture optimal for stable combustion in the engine combustion chamber even at a low temperature such as winter.
It is possible to prevent problems in actual vehicle performance such as deterioration of startability, in some cases, inability to start, or in the case of idling malfunction immediately after start, and in extreme cases, stall.

[0008] On the other hand, the 10% by volume distillation temperature, which is one of the necessary conditions, and the 50% by volume distillation temperature, which is more preferable, are measured according to JIS K 2254 "Petroleum products-distillation test method". is there. According to the present invention,
By setting the 0% by volume distillation temperature to 60 ° C. or lower and the 50% by volume distillation temperature to 100 ° C. or lower, the gas-liquid ratio of the air-fuel mixture flowing into the combustion chamber is optimized, and the dispersion of the fuel particles is achieved. The condition is good, preventing problems such as hesitation (acceleration response delay), stumbling (acceleration), and surge (vehicle longitudinal vibration) that often occur during acceleration immediately after engine start. And quick warm-up can be obtained.

Further, the content of the carbon atoms of 4 or less and 6 or less is a value determined by a gas chromatography method shown below. That is, the column has a length of 10
A dimethyl silicon capillary column having an inner diameter of 60 m and an inner diameter of 0.1 to 0.6 mm is used, a detector is a hydrogen ionization detector (FID), and a carrier gas is a flow rate of 0.3 to 1.5.
helium at ml / min, split ratio 1:50 to 1:
250, inlet temperature 150-270 ° C, detector temperature 150
Under the conditions of ２270 ° C., the column temperature was set to the initial temperature −10.
This is a value measured by raising the temperature from -10 ° C to the final temperature of 150-250 ° C.

The hydrocarbons having 4 or less carbon atoms measured therein include propane, propene, isobutane, normal butane, 1-butene, isobutene, trans 2-butene, and cis 2
And hydrocarbons having 6 or less carbon atoms, in addition to the above-mentioned hydrocarbons having 4 or less carbon atoms, normal pentane, isopentane, 2,2 dimethylpropane, 1 pentene, trans 2 pentene, cis 2 pentene 3 methyl 1
Butene, 2-methyl-1-butene, cyclopentane, cyclopentene, normal hexane, 2,2 dimethylbutane,
2,3 dimethyl butane, 2 methyl pentane, 3 methyl pentane, 3,3 dimethyl 1 butene, 4 methyl 1 pentene, 3 methyl 1 pentene, 2,3 dimethyl 1 butene, 4
Methyl cis 2 pentene, 4 methyl trans 2 pentene,
2 methyl 1 pentene, 1 hexene, 2 ethyl 1 butene,
Trans 3 hexene, cis 3 hexene, trans 2 hexene, cis 2 hexene, 2 methyl 2 pentene, 3 methyl cis 2 pentene, 3 methyl trans 2 pentene, 2, 3
Dimethyl 2-butene, benzene, cyclohexane, cyclohexene and the like.

By reducing the amount of hydrocarbons having 4 or less carbon atoms thus determined to 7% by volume or less, loading on gasoline trucks from gasoline shipping facilities such as refineries and oil depots, and loading from gasoline trucks Filling storage tanks at gas stations (service stations), storing gasoline at gas stations, refueling gasoline cars at gas stations, running gasoline cars, parking gasoline cars, and releasing light hydrocarbons into the atmosphere. Can be suppressed.

On the other hand, the hydrocarbon content of C6 or less is 35% by volume.
By the above, the gasoline-air ratio is improved in the combustion chamber at the time of low temperature such as in winter and immediately after the start, and a good combustion air-fuel mixture is formed in the vicinity of the ignition plug, and the startability, the idling stability, and the acceleration performance are realized. In addition, remarkable improvements in low-temperature operation and warm-up can be obtained.

[0013] The low vapor pressure unleaded gasoline of the present invention is not limited in other properties at all, but it has a research octane number (JIS K 2
280) is 89.0 or more, the density (JIS
K 2249) is 0.71 or more, and the 50% by volume distillation temperature is preferably 100 ° C. or less for maintaining the medium / low temperature operability. More preferably, the 50% by volume distillation temperature is 75% for maintaining the good high temperature operability. C or higher. In order to prevent the lubricating oil from being diluted with gasoline and to prevent deposits from adhering to the engine intake system, the 90% by volume distillation temperature is 180 ° C. or less, and the distillation end point is 2 ° C.
The sulfur content (JIS K2541) is desirably 100% by mass or less in order to prevent the engine exhaust gas catalyst from deteriorating.

An aromatic content of 45% by volume or less for preventing plug smoldering at low temperature and purifying exhaust gas. Prevents generation of insoluble matter in gasoline by purifying and storing exhaust gas and adhesion of the product to a fuel system. Therefore, the olefin content (JIS K 2536) is 30% by volume or less, and the oxidative stability (JIS K 2) in order to prevent the formation of insolubles in gasoline by storage and the adhesion of the product to the engine fuel system.
287) is 480 minutes or more, and real gum (JIS K 2261) is 5 mg / 1 to keep the engine fuel system clean.
It is preferable that the content of benzene (JIS K 2536) is 1.0% by volume or less from the viewpoint of purification of the air environment.

[0015] The low vapor pressure lead-free gasoline of the present invention is not limited in its production method, and can be produced by any method. As the gasoline base material used here, for example, liquefied gas obtained by distilling crude oil, light naphtha,
Heavy naphtha, cracked gasoline obtained by catalytic cracking / hydrocracking, etc., reformed gasoline obtained by catalytic reforming, polymerized gasoline obtained by olefin polymerization, alkylate alkylated hydrocarbons such as isobutane , Isomerized gasoline (isomerate) obtained by isomerizing light naphtha to isoparaffin, aromatic hydrocarbon compound,
Aromatic compounds obtained by alkylating benzene, naphthenic hydrocarbon compounds obtained by hydrogenating benzene, MTBE obtained by reacting methanol with isobutene
And the like.

Further, these base materials can be fractionated and used in an arbitrary distillation range. The base material fractionated by the distillation means, for example, that a reformed gasoline is divided into three components having 5 or less carbon atoms, 6 or more carbon atoms, and 7 or more carbon atoms, and then a fraction having 5 or less carbon atoms and 7 or more carbon atoms. Or a base material obtained by removing a fraction having 4 or less carbon atoms by distillation from light naphtha, cracked gasoline, reformed gasoline, or the like.

Typical amounts of these base materials can be exemplified as follows. Typically, these can be appropriately mixed according to the situation to prepare a low vapor pressure unleaded gasoline, but the combination must be carefully considered in consideration of the influence of the base materials. For example, when a liquefied gas is used, if it is frequently used, HC volatilization is increased, which is contrary to the object of the present invention. In addition, heavy naphtha causes a decrease in octane number, so it is set to less than 10%. Further, heavy use of cracked gasoline is disadvantageous because it causes the generation of actual gum. Also, heavy use of reformed gasoline deteriorates combustion in the engine, and causes the generation of residues in the combustion chamber and the occurrence of smoldering problems of the spark plug. (1) Liquefied gas: 0 to 7% by volume (2) Light naphtha and its distillation fraction: 0 to 25% by volume (3) Heavy naphtha: 0 to 10% by volume (4) Reformed gasoline and its distillation Fractionated fraction: 0 to 80% by volume (5) Cracked gasoline and its distillation fraction: 0 to 70% by volume (6) Alkylate and its fractionated distillation fraction: 0 to 40% by volume (7) Isomerism Gasoline: 0 to 30% by volume (8) Aromatic hydrocarbon compound: 0 to 45% by volume

The mixing may be carried out so that the finally obtained unleaded gasoline satisfies the requirements of the present invention.
It goes without saying that the type and mixing ratio of the base material are not particularly limited. In addition, in order to maintain the cleanliness of the engine fuel system, an amine system (for example,
A detergent of polyetheramine, polyisobutenamine or the like or an imide type (succinimide or the like) may be added at 0 to 300 ppm by volume.

[0019]

EXAMPLES Examples 1 to 4 and Comparative Examples 1 to 3 Hereinafter, the present invention will be described in more detail with reference to Examples 1 to 4 and Comparative Examples 1 and 2. It should be noted that the present invention is not limited by these examples. Table 1 shows the composition and properties of the gasoline base materials used in the examples and comparative examples.

[Table 1 Composition and properties of gasoline base material]

[Table 1] Using the base materials shown in Table 1, the gasoline samples of Examples 1 to 4 and Comparative Examples 1 to 3 were prepared in accordance with the mixing ratios of the base materials shown in Table 2.

[Table 2] Gasoline samples used in Examples and Comparative Examples

[Table 2] Table 3 shows the composition and properties of gasoline samples obtained according to the base materials in Table 2 and their mixing ratios (the component amounts in the table represent% by volume).

[Table 3 Properties and characteristic values of gasoline sample]

[Table 3] Using these samples, a volatilization test and an operability test were performed, and the results are shown in Table 4. In addition, each test method is as follows.

(1) Volatility test A gasoline filling hose is attached to the filler port of a 20-liter gasoline carrying can, and the attachment portion is completely sealed. While the air vent valve of the can is open, charge 5 L of test gasoline. After filling, close the air vent valve and leave for 30 minutes. After standing, attach an activated carbon adsorption device to the end of the air release valve and open the valve. Immediately 10L of test gasoline from filler port
Refuel. Five minutes after refueling, the system is allowed to stand with the air vent valve open (steam absorption by the activated carbon adsorption device), and then the weight increase of the activated carbon is measured. The test is performed at a constant temperature of 25 ° C.

(2) Drivability test A carburetor fuel-supplied commercial vehicle with a displacement of 1.5 L (A
Car) and an injector fuel-supplied passenger car (B) having a displacement of 2.0 L were used as test vehicles.
At 5 ° C., CRC (Coordinating)
The operation was performed in a mode based on the low-temperature or normal-temperature drivability test method specified by Research Research), and the evaluation was made in terms of starting time, idling stability (bodily sensation), and demerit in sensation drivability.

[Table 4 Results of Volatility Test and Drivability Test]

[Table 4]

From the test results, regarding the low-temperature operability test and the normal-temperature operability test, in Examples 1 to 4 and Comparative Example 1,
Both are satisfactory (Examples 1 to 4 and Comparative Example 1
The disadvantages are not significant enough to make a substantial difference. ).

On the other hand, Comparative Example 2 in which the Reid vapor pressure was 50 to 72 kpa and the 10% distillation temperature was less than 60 ° C. both (Reed vapor pressure 48.2 kPa and 10% distillation temperature 6
In the case of 1.5), both the low-temperature operability test and the normal-temperature operability test have a problem, and although the Reid vapor pressure and the 10% distillation temperature are satisfied, Comparative Example 3 in which the 50% distillation temperature exceeds 100 ° C.
(Lead vapor pressure 60.5 kpa, 10% distillation temperature 54.
At 0 and 50% distillation temperature of 102.5 ° C.), an improvement is seen from Comparative Example 1, but the operability is still unsatisfactory. Comparative Example 1 having a vapor pressure of 50 to 72 kpa and an amount of hydrocarbons having 4 or less carbon atoms of 7% by volume or less (Reed vapor pressure of 77.3 kpa, 10% distillation temperature of 4%)
5.0 and 50% distillation temperature of 92.0 ° C. and the amount of hydrocarbons having 4 or less carbon atoms of 7.1% by volume), the volatile gasoline (hydrocarbon) amount was reduced in the volatility test reproducing gasoline refueling. There are many problems.

However, in the case of Examples 1 to 4, the amount of volatilization indicated by the amount of activated carbon adsorbed is significantly improved as compared with Comparative Example 1. Furthermore, in Example 3 (vapor pressure 58.0 kpa) and Example 4 (vapor pressure 53.2 kpa) satisfying the Reid vapor pressure of 60 kpa or less, the volatilization amount is further reduced. The gasoline of Comparative Example 2 has no problem in volatility, but has a large problem in drivability as described above.

[0029]

The low vapor pressure unleaded gasoline of the present invention can reduce the amount of light hydrocarbons volatilized without impairing the low-temperature and normal-temperature driving performance of a vehicle. It contributes to improvement.

Claims (3)

[Claims] 1. Reed vapor pressure of 50 kPa or more to 72 k
Pa or less and a 10% by volume distillation temperature of 60 ° C. or less. 2. Reed vapor pressure is 50 kPa or more to 72 kPa
Pa or less, 10% by volume distillation temperature is 60 ° C or less,
An unleaded gasoline for a gasoline engine having a 50% by volume distillation temperature of 100 ° C or lower. 3. The gasoline according to claim 1, wherein the content of hydrocarbons having 4 or less carbon atoms is 7% by volume or less, and the content of hydrocarbons having 6 or less carbon atoms is 35% by volume or more. Unleaded gasoline for engines.