JPS61207496A - Fuel for internal-combustion engine - Google Patents

Abstract

PURPOSE:To provide the titled fuel capable of providing an octane value comparable or superior to methanol and ethanol and correcting various drawbacks of methanol etc., by using a specific lower carbonate or a mixture thereof with a hydrocarbon fuel for a fuel of an internal-combustion engine. CONSTITUTION:The titled fuel comprising at least one compound of the formula (wherein R1 and R2 are each independently 1-4C alkyl) or comprising a lower carbonate and a hydrocarbon fuel. Preferred lower carbonates are dimethyl carbonate, methylethyl carbonate and diethyl carbonate because they are available at a relatively low cost without use of a petroleum resource. When the lower carbonate is mixed with the hydrocarbon fuel to obtain a mixed fuel, it is preferred that the lower carbonate is used in an amount of 3vol. or more per 100vol. the hydrocarbon fuel. The lower carbonate greatly contributes to the improvement in octane value of a gasoline particularly for automobiles.

Description

[Detailed Description of the Invention] [Industrial Field of Application and Prior Art] In recent years, for the purpose of saving petroleum resources, methanol or ethanol (hereinafter both are collectively referred to as "lower alcohols") has been used as automobile gasoline, etc. Attempts have been made to use them as substitutes or in combination.

However, lower alcohols: (1) have a high octane number; If used together, increase the octane rating of the gasoline.

(2) Exhaust gas is relatively clean.

(3) Can be manufactured without using petroleum resources as raw materials.

(4) It has poor compatibility with gasoline, etc., and there is a limit to the amount that can be added when mixed.

(5) Easy to absorb water. Even if it absorbs a small amount of water, it will undergo phase separation from gasoline, etc.

(6) Low vapor pressure makes starting in cold weather difficult.

(7) It absorbs moisture and easily corrodes the intake system.

These fatal drawbacks have prevented its widespread use in internal combustion engines.

[Means for Solving the Problems and Their Effects] However, the properties of carbonic esters regarding their octane number are not known, and no attempts have been made to use them as fuels for internal combustion engines. However, when the present inventors investigated the characteristics of this low-molecular substance as a fuel for internal combustion engines, they surprisingly found that it had an octane number-improving effect, and in fact, its effect was even superior to that of lower alcohols. It became clear. Furthermore, it does not have the disadvantages (4) to (η) mentioned above that lower alcohols have, and has other good properties in various respects required for heating materials for internal combustion engines. This was achieved based on extensive knowledge.

That is, the present invention provides a compound (hereinafter referred to as a "lower carbonate ester") represented by the general formula (in the formula, R1 and R are both different or the same alkyl group having 1 to 4 carbon atoms). The gist is a fuel for an internal combustion engine consisting of at least one type of (collectively referred to as ``carbonate'') or a lower carbonate ester and a hydrocarbon fuel.

There are 36 compounds represented by the above general formula, and any of them can be applied to the present invention. this house,
Dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, or a mixture thereof is preferable in that it can be obtained relatively inexpensively using coal, natural gas, biomass, etc. as a starting material without using petroleum resources. In terms of vapor pressure,
Such low molecular weight ones are better. &C, Diethyl carbonate has no toxicity and is optimal in this sense.However, the effect on octane number is due to side chains in alkyl groups such as diisopropyl carbonate, diimbutyl carbonate, di-5eC-butyl carbonate, di-tert-butyl carbonate, etc. It is better to have

In the present invention, when a hydrocarbon fuel is used, the fuel may be any fuel for internal fuel engines, and the present invention improves the characteristics of these fuels, but knocking is a particular problem. Therefore, the present invention exhibits a remarkable effect.As is clear from the example of diethyl carbonate in the drawing, the effect of increasing the octane number of gasoline is extremely large. Either lead gasoline or unleaded gasoline may be used. Lower carbonate esters and hydrocarbons can be mixed in any ratio, but in practice, 3 or more parts by volume of lower carbonate esters per 100 parts by volume of hydrocarbon fuel. Preferably, 5 parts by volume or more may be mixed.

The present invention can also be applied to fuel for internal combustion engines containing lower alcohols to cover the disadvantages of lower alcohols.

In the present invention, the effect of the lower carbonic ester on the octane number, that is, the effect of the lower carbonic ester on improving the octane number of itself and the octane number of hydrocarbon fuel, is equal to or 5 times lower than that of the lower alcohol. As mentioned above, this effect is particularly high when the alkyl group has a side chain.

Lower carbonate esters are extremely compatible with hydrocarbon fuels (in particular, they dissolve in any proportion with automobile gasoline, and do not dissolve water.

Therefore, the mixed fuel of the lower carbonic acid ester and the hydrocarbon fuel according to the present invention always maintains a uniform mixed state, and troubles due to phase separation between the two do not occur. As mentioned above, lower alcohols tend to undergo phase separation from hydrocarbon fuels, but in the present invention, this phase separation can be easily suppressed even when lower alcohols are included. Moreover, even if it is used in combination with an additive such as tertiary-butyl methyl ether, its function is not impaired.

As mentioned above, lower carbonate esters have low bath solubility in water, so according to the present invention, they are less likely to cause corrosion problems like lower alcohols.

Furthermore, although lower carbonate esters have higher boiling points than lower alcohols, their vapor pressure at low temperatures is much higher. (That is, the fluctuation in vapor pressure with respect to fluctuation in temperature is small.) Therefore, according to the present invention, starting in cold weather is easy.

As mentioned above, low molecular weight lower carbonate esters are particularly excellent in this respect.

In addition, the fuel for internal combustion engines of the present invention has good scavenging properties;
The exhaust gas is relatively clean, and in particular - there is little carbon oxide; the output is sufficient, and the acceleration is good; the fuel consumption is low; and there is no coloration.

The fuel of the present invention can be mixed with heavy oil, light oil, kerosene, etc. in an appropriate amount and used as a fuel for other than internal combustion engines, such as boilers.

〔Example〕

Examples 1 to 3 and Comparative Examples 1 to 3 Research Method The materials shown in Table 1 were added to regular gasoline having an octane number of 90, and the physical properties of each were measured. Research Method The octane number was determined by the method of J-K8-2280. The exhaust gas test car is Cedric Custom 6,19.
98cc, compression ratio & 5° engine type L-20, maximum output 100. PS is 15000 rpm and has traveled 150000 Km so far.

Exhaust gas is at idle link (rotation speed 600 rpm)
A sample was taken from the exhaust port into the syringe of IQQcc, and O, N, co, co, and other hydrocarbons were analyzed by gas chromatography. NOx was measured by the Zar-Raman method.

The results are shown in Table 1.

Addition of alkyl carbonate reduces moisture in exhaust gas and reduces C
Regarding O and NOx, almost the same results as methanol addition were shown.

In Examples 1 and 2, formaldehyde of 100 ppm or more was not detected.

[Brief explanation of drawings]

The drawing is a graph showing the effect of diethyl carbonate on improving the octane number.

Claims (4)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 and R_2 both have 1 to 4 carbon atoms.
are different or the same alkyl group. ) (hereinafter collectively referred to as "lower carbonate esters"), or a fuel for internal combustion engines comprising a lower carbonate ester and a hydrocarbon fuel. (2) The fuel for an internal combustion engine according to claim 1, wherein the lower carbonate ester is dimethyl carbonate, methylethyl carbonate, or diethyl carbonate. (3) Lower carbonate ester and hydrocarbon fuel of 3 or more:
100 (volume ratio) of the fuel for an internal combustion engine according to claim 1 or 2. (4) The fuel for an internal combustion engine according to claim 3, wherein the hydrocarbon fuel is automobile gasoline.