JPH0348349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an apparatus for supplying emulsion fuel consisting of fuel oil, water and lower alcohol to a combustion chamber of an internal combustion engine.

(Prior Art) In recent years, there has been a strong demand for reducing NOx emitted from land-based internal combustion engines from the standpoint of preventing air pollution. Furthermore, from the standpoint of energy conservation, it is required to save fuel consumption without sacrificing engine performance.

On the other hand, it has become known that injecting water or alcohol into the intake air of an internal combustion engine is effective in reducing NOx in exhaust gas and preventing knocking. A method of direct injection and a method of injecting water or alcohol into the intake pipe have been devised.

However, in the former case, since the injection nozzle directly comes into contact with the high-temperature combustion gas, there is a problem that the nozzle is easily clogged and it is difficult to take countermeasures against heat. Furthermore, in the latter case, water or alcohol vaporizes and expands during the suction process, which reduces the effect of sucking the mixed gas, resulting in a reduction in engine output.

Therefore, the use of emulsion fuel has been proposed as a method to solve these problems.

That is, this emulsion fuel is made by dispersing an appropriate amount of water in the form of fine particles in fuel oil, and has already been put into practical use in some marine diesel engines, particularly for the purpose of saving fuel consumption and maintenance management costs.

The NOx suppression effect of emulsion fuel is due to the lowering of combustion temperature due to the latent heat of vaporization of water, the reduction of oxygen concentration in the combustion chamber due to generated water vapor, and the atomization and stirring effect of fuel oil due to the rapid vaporization and expansion of fine water particles. It is generally believed that this is due to synergistic effects such as shortening combustion time and suppressing the occurrence of localized high-temperature areas, as the mixing of air and fuel oil is promoted and combustion is simultaneously carried out over a wide combustion range.

(Problems to be Solved by the Invention) However, when such an emulsion fuel is used in a land-based internal combustion engine, there are various problems that must be solved as follows.

In other words, it is possible to significantly reduce NOx due to strict exhaust gas regulation conditions, and therefore it is possible to obtain a stable emulsion fuel in which fine water particles are homogeneously dispersed. This is to prevent engine performance from deteriorating, and to prevent water from freezing in cold regions.

Among these problems, as a countermeasure against freezing water, the use of ethylene glycol, which has been conventionally used in antifreeze liquid for cooling, can be considered. However, this ethylene glycol has a large molecular weight, and a sufficient antifreeze effect cannot be obtained unless it is added in a considerable amount to water, making it unsuitable for use as an emulsion fuel.

Therefore, the present invention attempts to solve these problems all at once, and makes it possible to significantly reduce NOx in exhaust gas without reducing the performance of the internal combustion engine, and also to prevent water from freezing even in cold regions. It is an object of the present invention to provide an emulsion fuel supply device for an internal combustion engine that does not cause trouble.

[Structure of the Invention] (Means for Solving Problems) An emulsion fuel supply device for an internal combustion engine according to the present invention is an emulsion fuel supply device for an internal combustion engine that supplies emulsion fuel to a combustion chamber of an internal combustion engine. first and second mixers each having a first and second mixer configured to move the position while the fluid passes through the fluid passage, mix the fluid, and discharge the fluid from the outlet of the fluid passage; raw material supply means for pumping fuel oil, water, and methanol or ethanol to the first mixer; and emulsion fuel pumping for pumping the emulsion fuel obtained by mixing in the first mixer to the second mixer. The invention is characterized in that the methanol or ethanol is contained in an amount represented by at least the following formula.

T = -0.5806 x WM (for methanol) T = -0.403 x WE (for ethanol) where T: ambient temperature below freezing (°C) WM: amount of methanol mixed per 100 g of water (g) WE: per 100 g of water Mixing amount of ethanol (g) Examples of mixers used in the first and second mixers of the present invention include Himixer (trade name, manufactured by Toray Industries, Inc.), Static Mixer (trade name, manufactured by Kenix Corporation), and SMV mixer. (Product name: Manufactured by Sulza)
etc. can be mentioned.

Further, as the lower alcohol used in the present invention, methanol and ethanol having a small molecular weight are suitable from the viewpoint of effectiveness and economy.

These alcohols have an energy-lowering effect on the surface of water and are present in large quantities (20 to 20% compared to fuel oil).
It is possible to form a stable emulsion fuel in which water (approximately 65%) is homogeneously dispersed with a small particle size of 2 to 3 μm.

That is, the dispersed particle size d ₃₂ of an emulsion is generally expressed as d ₃₂ =cD ₀ We ^-a Re ^b . Here, Re is Reynolds number =
D ₀ ρV/η, We is Weber number = D ₀ V ² ρ/σ (ρ
= fluid average density, V = flow rate of the mixed liquid, η = fluid viscosity, σ = interfacial tension of the two liquids), and a,
b and c are characteristic values determined by the type of mixing element of the mixer, and D ₀ is the direct line of the mixer.

To give specific numbers, when only water is used, σ = 35dyne/cm, We = 87.4, d ₃₂ = 130μm
On the other hand, in water with 44% methanol added, σ = 0.02dyne/cm, We = 152.96, d ₃₂ =
It becomes 3μm.

In addition, the alcohol in emulsion fuel has the effect of lowering the freezing point of water, and if water is mixed alone, the water particles in the emulsion will freeze and the emulsion fuel will lose its function. enable application.

Taking methanol as an example, the relationship between the mixing ratio of water and methanol and the ambient temperature is expressed by the following equation.

T=-0.5806×WM Where, T is the ambient temperature below freezing (℃), WM
is the amount (g) of methanol mixed per 100 g of water.

Further, for ethanol, it is expressed by the following formula.

T=-0.403×WE However, WE is the amount (g) of ethanol mixed per 100 g of water.

In addition, in the usage environment of this apparatus, the atmospheric temperature (°C) below freezing point is within a realistic range of approximately -30°C, and within this range, the present invention can be fully applied.

In addition, when using a mixture of methanol and ethanol, the amount is determined by the algebraic average of both.

Therefore, in the present invention, the blending amounts of fuel oil, water, and alcohol are determined in consideration of the above points and the startability, stability, etc. of the internal combustion engine.

In addition, in the present invention, other emulsifiers can be added, and nonionic emulsifiers having an HLB of 7 or less are suitable as emulsifiers because they can provide a stable emulsion fuel.

Furthermore, in the present invention, methyl cellulosolve or ethyl cellulosolve may be added. By adding these, water is dissolved in the fuel oil by a few percent, but the effects of the present invention can be obtained.

(Function) In the emulsion fuel supply device for an internal combustion engine of the present invention, while passing through the first mixer, fuel oil,
The water and alcohol are mixed to form an emulsion and then pumped to a second mixer to further refine and homogenize the water particles to form a stable emulsion fuel that is injected into the combustion chamber.

In this way, alcohol is added to fuel oil along with water, and by going through two stages of emulsion, a homogeneous and stable emulsion fuel is formed and injected into the combustion chamber, reducing NOx emissions.
is extremely effectively reduced. Moreover, even in cold regions where the temperature is below 0°C, the original characteristics of emulsion fuel can be exhibited and sufficient NOx reduction can be achieved.

(Example) Hereinafter, an example of the present invention shown in the drawings will be described in detail.

FIG. 1 is a block diagram schematically showing an embodiment of the present invention, and is an example in which all the components are installed in the internal combustion engine.

In the figure, 1 is a fuel tank containing fuel oil such as diesel oil, 2 is a water/alcohol mixed liquid tank containing a water/alcohol mixed liquid, and these are for fuel oil supply into which a pump 3 is inserted. Piping 4
It is connected to a first in-line mixer 7 via a water/alcohol mixed liquid supply pipe 6 into which a pump 5 is inserted. Fuel oil supply pipe 4 and water
The alcohol mixed liquid supply pipe 6 is connected in front of the first in-line mixer 7. In addition, when adding an emulsifier, it is added to the fuel oil tank 1 or the water/alcohol mixture tank 2 in advance.

The first in-line mixer 7 includes a plurality of mixing elements inserted into a fluid passage, and is configured so that the pumped fluid is mixed while repeating positional movement, division, and merging.

This first inline mixer 7 is connected to a primary emulsion fuel tank 8 and is connected to a primary emulsion fuel supply pipe 10 in which a pump 9 is inserted. It is connected to the second in-line mixer 11. The outlet of this second in-line mixer 11 is connected to the combustion chamber 12 of the internal combustion engine.

The above is the main line of this embodiment, and the following sub-lines are provided to improve the reliability and safety of this device.

That is, the secondary emulsion fuel or fuel oil discharged from the second in-line mixer 11,
An emulsion fuel return line 13 and a fuel oil return line 14 are used to return fuel oil to the primary emulsion fuel tank 8 or fuel oil tank 1, respectively, depending on changes in engine load, and as an emergency measure, fuel oil is returned directly from the fuel oil tank 1. Combustion chamber 1 of an internal combustion engine
An emergency fuel oil line 15 that enables supply to the pumps 3 and 2; and a level switch 16 that enables on/off operation at the upper and lower limits of the liquid level of the primary emulsion fuel tank 8; A motor operating switch 17 for operating the pump 5 is provided.

In the emulsion fuel supply device configured in this way, the fuel oil and the water/alcohol mixture are
A predetermined flow ratio, flow pressure, and flow rate are supplied from the fuel oil tank 1 and the water/alcohol mixed liquid tank 2 through the fuel oil supply pipe 4 and the water/alcohol mixed liquid supply pipe 6 by the pump 3 and the pump 5. The fuel is pumped downward to a first in-line mixer 7 and mixed to form a primary emulsion fuel.

Note that since the flow ratio and flow rate of both liquids affect the size of the dispersed particles formed, it is preferable that pump 3 and pump 5 be operated under a constant load.

Next, the obtained primary emulsion fuel is once held in the primary emulsion fuel tank 8, and then
The primary emulsion fuel is pumped by a pump 9 through a primary emulsion fuel tank 8 to a secondary in-line mixer 11;
Here, they are mixed again and adjusted to a homogenized and stable secondary emulsion fuel with emulsion particles having a size of about 2 to 3 μm, and then injected into the combustion chamber 12 of the internal combustion engine.

A portion of the emulsion fuel is returned to the primary emulsion fuel tank 8 via the emulsion fuel return line 13 in response to changes in the engine load, that is, changes in the flow rate of the emulsion fuel.

Note that in this embodiment, the combustion chamber 1 of the internal combustion engine
The supply pressure of the emulsion fuel to No. 2 is very high and can reach several hundred atmospheres, so each pipe is designed to withstand high pressure.

In the emulsion fuel supply system for internal combustion engines constructed in this way, when 40 g of methanol was mixed with 100 g of water, it did not freeze down to -20°C. On the other hand, when 30 g of methanol was mixed with 100 g of water, freezing was observed at -20°C.

FIG. 2 shows another embodiment, which is basically the same as the embodiment shown in FIG. 1, and common parts are given the same reference numerals.

However, while the previous embodiment is an example in which all the components are installed in the internal combustion engine, in this embodiment, the primary emulsion fuel is manufactured in advance (indicated by A in the figure), and the primary emulsion fuel is pre-produced in the internal combustion engine. This is an example in which only 8 or less primary emulsion fuel tanks (indicated by B in the figure) are installed.

Therefore, in FIG. 2, the pumps 3 and 5 are operated at preset flow rate ratios, flow rates, and flow pressures, and are stopped as soon as the required amount of primary emulsion fuel is supplied to the primary emulsion fuel tank 8. Therefore, the only difference is that the level switch 16 and motor operation switch 17 shown in FIG. 1 are no longer necessary.

In addition, in FIG. 2, 18 is a drain of the first in-line mixer 7.

[Effects of the Invention] As explained above, according to the emulsion fuel supply device of the present invention, alcohol is added to fuel oil along with water, and the dispersed particles are homogeneously made fine by undergoing two-stage emulsion formation. Since a strong and stable emulsion fuel is formed and injected into the combustion chamber, NOx emissions are extremely effectively reduced without compromising the performance of the internal combustion engine. Moreover, even in cold regions where the temperature is below 0℃, the original characteristics of emulsion fuel can be fully demonstrated.
It is possible to reduce NOx.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
The figure is a configuration diagram showing another embodiment of the present invention. 1... Fuel oil tank, 2... Water/alcohol mixed liquid tank, 3, 5, 9... Pump, 4... Fuel oil supply pipe, 6... Water/alcohol mixed liquid supply pipe, 7... First in-line mixer, 8...
...Primary emulsion fuel tank, 10...Primary emulsion fuel supply piping, 11...Second in-line mixer, 12...Combustion chamber of internal combustion engine, 1
3... Emulsion fuel return line, 14...
... Fuel oil return line, 15 ... Emergency fuel oil line, 16 ... Level switch, 17 ... Motor operation switch, 18 ... Drain of first in-line mixer.

Claims (1)

[Scope of Claims] 1. An emulsion fuel supply device for an internal combustion engine that supplies emulsion fuel to a combustion chamber of an internal combustion engine, which has a fluid passage, and while the fluid passes through the fluid passage, the position is moved and mixed. Raw material supply means for force-feeding fuel oil, water, and methanol or ethanol to first and second mixers configured to be discharged from an outlet of the fluid passage, and to the first mixer on the upstream side. and emulsion fuel pumping means for pumping the emulsion fuel mixed by the first mixer to the second mixer, the methanol or ethanol is at least in an amount expressed by the following formula: An emulsion fuel supply device for an internal combustion engine, comprising: T = -0.5806 x WM (for methanol) T = -0.403 x WE (for ethanol) where T: ambient temperature below freezing (°C) WM: amount of methanol mixed per 100 g of water (g) WE: per 100 g of water Mixed amount of ethanol (g)