JP2001065411A - Emulsion fuel supply device of diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emulsion fuel supply device of a diesel engine showing a high responsiveness to change in a water ratio by reducing an emulsifing fuel amount. SOLUTION: This device is a loop passing a mixer 45 provided before the fuel flow in part to the fuel injection part 3 in a fuel circulation loop, an emulsion fuel return line 46 for communicating a fuel return line 26 with the position near suction side of the mixer 45 and a fuel injection part 3 and is provided with an emulsion fuel circulation loop formed smaller than the inner volume of the fuel circulation loop and a controller for switching the fuel circulation loop to the emulsion fuel circulation loop. By the switching of the controller, an operatable pure fuel circulation loop is formed separatingly from the emulsion fuel circulation loop. Thereby, the amount of an emulsified fuel is reduced in comparison with the past and change in the water ratio of the fuel can be carried out in a short time and the responsiveness becomes high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an emulsion fuel supply device as a countermeasure against low NOx of a diesel engine whose load frequently changes, such as a ship.

[0002]

2. Description of the Related Art First, an example of a basic configuration of a normal diesel engine will be described with reference to FIG. As shown in the figure, the diesel engine has the fuel booster zone 1
And a fuel pressurization and circulation zone 2 and a fuel injection zone 3 (fuel injection unit). In fuel booster zone 1, pure fuel (heavy oil) in fuel tank 4 (pure fuel supply source)
Is the booster suction pipe 13, the suction filter 10,
The pressure is increased through the booster pump 11 and the booster outlet pipe 14 and supplied to the pulsation damper 20 of the adjacent fuel pressurization circulation zone 2. The booster outlet pipe 14 is connected to the fuel tank 4 via a booster return pipe 15 via a booster pressure regulating valve 12, and a part of the pressurized pure fuel is returned to the fuel tank 4.

[0003] In the fuel pressurized circulation zone 2, a pulsation damper 2 is provided.
The pure fuel rectified through 0 is pressurized by the pressurized circulation pump 21 so as to have a pressure and a flow rate necessary for injection into the engine by a fuel injection pump 31 described later. The pressurized fuel is further heated by the heater 22 to a desired temperature in the heavy oil property at that time, passes through the primary filter 23 and the secondary filter 24, and passes through the pressurized circulation outlet pipe 25.
To the fuel injection zone 3.

Further, a fuel return line 26 for returning pure fuel from the outlet side of the fuel injection zone 3 is connected to the pulsation damper 20. Therefore, fuel booster zone 1
Is mixed with the pure fuel returned from the engine through the fuel return line 26, and is pressurized by the pressurized circulation pump 21 as described above.

The fuel injection zone 3 is provided with a pressure circulation circulation pipe 32, a pressure circulation pressure regulating valve 30, and a pressure circulation return pipe 33 in order from the upstream side. Injection pump 31 via branch pipe between circulation return pipe 33
Is provided. Pure fuel supplied from the fuel pressurized circulation zone 2 to the fuel injection zone 3 is supplied to the pressurized circulation outflow pipe 3
The pressure is adjusted by the pressurizing and circulating pressure regulating valve 30 via the pressurizing and circulating pressure return valve 33 so as to maintain a constant pressure difference between the pressure and the return line 33. Is supplied to the injection pump 31 which leads to

[0006] The remaining pure fuel, which is injected into the engine and consists of surplus fuel and pure fuel that has passed through a bypass passage (not shown) inside the injection pump 31, is fed to a branch of the pressurized circulation return pipe 33. After returning to the pipe, the fuel is returned to the pulsation damper 20 through the fuel return line 26. That is, the pressurized circulation pump 21 and the heater 2
2, a filter 23, 24, a fuel injection zone 3, a fuel return line 26, and a pulsation damper 20 constitute a fuel circulation loop.

FIG. 6 shows the diesel engine shown in FIG. 5 provided with a mixer 45 as an emulsion fuel forming means. The mixer 45 is provided between the pressurized circulation pump 21 and the heater 22, and is configured to supply water based on a detection signal of a transmission type pure fuel flow meter 44 provided in the booster outlet pipe 14 of the fuel booster zone 1. They are supplied in proportion. By the operation of the mixer 45,
An emulsion fuel which is a mixture of a pure fuel and water is formed, and the emulsion fuel circulation loop when operating with the emulsion fuel is the same as the fuel circulation loop as shown in FIG.

[0008]

As described above, the conventional diesel engine equipment has the following problems because the emulsion fuel circulation loop has a structure that uses the fuel circulation loop as it is.

The fuel circulation loop needs to be forcibly circulated by the pressurized circulation pump 21 in order to prevent heat from staying in the injection pump 31, especially in the case of a medium or large engine.
Further, before starting, the heater 22 and the filters 23 and 24 need to be circulated for stabilizing the pure fuel temperature and removing the staying air, so that the loop length is inevitably increased. As a result, in the conventional emulsion fuel circulation loop, the loop length becomes unnecessarily longer than the fuel consumption, and the large-volume filters 23, 24 and the like are present in the middle. The required fuel volume becomes unnecessarily large.

As a result, when the water content is changed, a long time is required for changing the water content because a large amount of the emulsion fuel having the water content before the change remains. That is, there is a problem that the change of the water addition rate is not immediately reflected (low response).

In particular, when the drainage operation is performed before the engine is stopped, the primary filter 23 and the secondary filter 2
4, the emulsion fuel present in the heater 22 becomes a complicated flow due to the low flow velocity in that portion, and the phenomenon of stagnation in that portion is apt to occur. I was

An object of the present invention is to provide an emulsion fuel supply apparatus for a diesel engine which can reduce the amount of fuel to be emulsified and which exhibits a high response to a change in the water content.

[0013]

To achieve the above object, an emulsion fuel supply apparatus for a diesel engine according to a first aspect of the present invention comprises a pure fuel supply source and a fuel supplied from the pure fuel supply source. Pressurizing means for pressurizing, a fuel injector for injecting a part of the pressurized fuel into a cylinder of the engine, and returning the remaining fuel not injected by the fuel injector to the suction side of the pressurizing means; A fuel circulation loop passing through a fuel return line, the emulsion fuel forming means provided in front of a fuel inflow to the fuel injection unit in the fuel circulation loop,
A loop that passes through the emulsion fuel return line that branches off from the fuel return line and communicates with a position near the suction side of the emulsion fuel forming means, and that is formed to be smaller than the internal volume of the fuel circulation loop. A pure fuel return line provided between the emulsion fuel circulation loop, a point before the junction of the emulsion fuel return line in the fuel circulation loop, and a downstream point of the branch point of the emulsion fuel return line, and the pure fuel return line. A pure fuel circulation loop passing through a pressure adjusting means provided in the return line, and a controller for switching communication between the fuel circulation loop and the emulsion fuel circulation loop, wherein the pure fuel circulation loop and the emulsion fuel circulation loop are: By switching the controller, it can be independently circulated. The one in which the features.

According to the present invention, the pure fuel circulation loop and the emulsion fuel circulation loop are switched by the controller so as to be separately operable, and the internal volume of the emulsion fuel circulation loop is equal to the fuel volume. Since it is formed smaller than the internal volume of the circulation loop, the amount of fuel to be emulsified is smaller than that of the conventional structure, and it is possible to change the water addition rate of the fuel in a short time, resulting in high-speed response. Emulsion fuel supply device can be realized. In addition, since the fuel circulation loop has a configuration similar to the conventional circulation system as necessary, the injection pump or heater can be forcibly circulated by the pressurized circulation pump, especially in the case of a medium-sized or large engine. -It is possible to stabilize the pure fuel temperature of the filter and remove the stagnant air.

According to a second aspect of the present invention, in the emulsion fuel supply device for a diesel engine according to the first aspect, a filter and / or a heating means provided in the fuel circulation loop includes the emulsion fuel. It is characterized by being configured to be located outside the circulation loop.

According to the present invention, since there is no conventional filter or heating means in the emulsion fuel circulation loop, the problem of the stagnation phenomenon is almost eliminated, and the change of the water addition rate of the fuel can be further reduced in a short time. It can be performed smoothly.

According to a third aspect of the present invention, there is provided the emulsion fuel supply device for a diesel engine according to the first aspect or the second aspect, wherein a branch point between the fuel return line and the emulsion fuel return line is connected to a pure water. A pure fuel on-off valve is provided between the confluence with the fuel return line, an emulsion circulation pump and an emulsion fuel on-off valve are provided in the emulsion fuel return line of the emulsion fuel circulation loop. According to the control signal, when the operation with pure fuel is performed, the on-off valve for pure fuel is opened and the emulsion fuel forming means is kept in an inactive state, and when the operation with emulsion fuel is performed, The on-off valve for pure fuel is closed,
The emulsion circulation pump is operated, the emulsion fuel on-off valve is opened, and the emulsion fuel forming means is operated.

According to the present invention, according to the control signal of the controller, when the fuel circulation loop is operated, the pure fuel on-off valve is opened and the emulsion fuel forming means is kept in the inactive state, while the emulsion fuel circulation is maintained. When the loop is operated, the pure fuel on-off valve is closed, the emulsion circulation pump is operated, the emulsion fuel on-off valve is opened, and the emulsion fuel forming means is operated. Therefore, switching between the fuel circulation loop and the emulsion fuel circulation loop can be realized with a simple structure, and each operation after the switching can be performed reliably and stably.

According to a fourth aspect of the present invention, there is provided the emulsion fuel supply apparatus for a diesel engine according to any one of the first to third aspects, wherein a pure fuel flow meter is provided to connect the emulsion through the fuel circulation loop. A fuel supply loop is provided at a position where fuel is supplied to the fuel circulation loop, and the amount of water in the emulsion fuel forming means is controlled based on a detection signal of the pure fuel flow meter. It is.

According to the present invention, since the arrangement of the pure fuel flow meter is in the vicinity of the point before the junction with the emulsion fuel circulation loop, the accuracy of measuring the fuel consumption in the engine is improved. Can be controlled with high accuracy.

According to a fifth aspect of the present invention, there is provided the emulsion fuel supply device for a diesel engine according to any one of the first to third aspects, wherein a pure fuel flow meter is provided from the pure fuel supply source. It is provided on a supply line to a fuel circulation loop, and is configured to control the amount of water in the emulsion fuel forming means based on a detection signal of the pure fuel flow meter. .

According to the present invention, since the pure fuel flow meter is disposed on the line before the junction from the fuel supply source to the fuel circulation loop, the pure fuel flow meter is provided in the fuel return line. Since the flow rate of the pure fuel flow meter can be measured without being affected by the opening / closing of the on-off valve, the fuel flow rate can always be measured according to the consumption of the engine, and stable control can be easily performed. .

According to a sixth aspect of the present invention, there is provided the emulsion fuel supply device for a diesel engine according to any one of the first to fifth aspects, wherein the pure fuel for forming the pure fuel circulation loop is provided. The pressure regulating means provided in the return line is characterized by using a sub-pressure regulating valve set at a higher pressure than the main pressure regulating valve provided in the fuel circulation loop.

With the provision of the sub-pressure regulating valve of the present invention, when the pure fuel on / off valve is closed and the operation is shifted to the operation of the emulsion fuel circulation loop from the operation state by the fuel circulation loop, the pressure by the pressure regulating means is changed. Since the adjustment is started, a smooth transition can be realized.

According to a seventh aspect of the present invention, there is provided the emulsion fuel supply apparatus for a diesel engine according to any one of the first to sixth aspects, wherein the position outside the emulsion fuel circulation loop is A temperature sensor for pure fuel is disposed between a junction of the emulsion fuel return line in the fuel circulation loop and the heating means, and is in a line for sending water to the emulsion fuel forming means and downstream from the water temperature variable section. A water temperature sensor is disposed at a position, and is configured to drive and control the water temperature variable unit in a direction in which the detected water temperature of the water temperature sensor matches the detected fuel temperature of the pure fuel temperature sensor. Is what you do.

According to the present invention, in actual operation, heating of the pure fuel is performed to keep the viscosity of the pure fuel at a constant value. In this case, it is necessary to appropriately change the temperature depending on the properties of the pure fuel. In the flow of the present invention, water is added to the heated pure fuel when the emulsion fuel is formed. Therefore, the temperature of the heated pure fuel is set to a set value, and the temperature of the added water is set to the pure fuel. By making the temperature equal to the temperature (set value), even if the fuel temperature changes according to the change of the fuel property, it is possible to automatically form an emulsion fuel keeping the target temperature.

According to an eighth aspect of the present invention, there is provided the emulsion fuel supply apparatus for a diesel engine according to any one of the first to sixth aspects, wherein the position outside the emulsion fuel circulation loop is A pure fuel temperature sensor disposed between the junction of the emulsion fuel return line in the fuel circulation loop and the heating means; an emulsion fuel temperature sensor disposed in the emulsion fuel circulation loop; A water temperature variable section provided in a line for sending water to the emulsion fuel forming means in a direction in which the detected temperature of the emulsion fuel temperature sensor matches the detected fuel temperature of the emulsion temperature sensor. It is characterized by having.

According to the present invention, in the case of an engine using fuel such as fuel oil C, a fuel oil viscosity measuring device usually called a viscosity sensor is provided at the outlet of the heater, and the temperature of the heater outlet is adjusted by this signal. Often done. In such a case, since the temperature automatically changes depending on the properties of the heavy oil, ignoring this temperature and keeping the water addition temperature constant may cause a problem.

Particularly, when the engine load is light, the fuel consumption is reduced, and the line temperature may increase due to the heat generated in the emulsion circulation system. In addition, depending on the heat radiation design of the piping, it is also conceivable that the temperature may be reduced. In such a case, the emulsion fuel temperature is measured by the emulsion fuel temperature sensor, and the temperature of the water injected into the emulsion fuel forming means is controlled so that the measured value is the same as the value measured by the pure fuel temperature sensor. By doing so, stable temperature control can be realized even at a light load. Still other objects and advantages of the present invention will become apparent from the following detailed description and drawings.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a diesel engine according to the present invention, and FIG. 2 is a standard configuration diagram of a water injection control mechanism for producing an emulsion fuel.
The “fuel circulation loop” according to the present embodiment is different from the conventional one shown in FIG. 6 in that a mixer 45 serving as an emulsion fuel forming means is provided, and a pure fuel on-off valve 41 is provided in a fuel return line 26. However, since the other configurations are common, the differences are explained,
The common parts are denoted by the same reference numerals and the description is omitted.

A mixer 45, which is an emulsion fuel forming means, is provided in the fuel circulation loop before a fuel inflow section into the fuel injection zone 3, which is the fuel injection section.

The “emulsion fuel circulation loop” according to the present embodiment corresponds to the fuel injection zone 3 of the fuel return line 26.
It is constituted by a loop passing through the emulsion fuel return line 46 that communicates the vicinity position and the position near the suction side of the mixer 45, and the fuel injection zone 3, and is formed smaller than the internal volume of the fuel circulation loop. . That is, the filters 23 and 24, the pressurized circulation pump 21 and the heater 22 which is a heating means disposed in the fuel circulation loop are arranged outside the emulsion fuel circulation loop in the present invention.

"Pure fuel circulation loop" according to the present embodiment
A pure fuel return line 66 provided between a point before the junction 47 with the emulsion fuel return line 46 in the fuel circulation loop and downstream of a branch point 100 of the emulsion fuel return line 46; Pressure regulating valve 40 as means and pressurized circulation pump 21 as pressurizing means
And a loop passing through a heater 22 as a heating means.

The communication between the fuel circulation loop and the emulsion fuel circulation loop is switched by the controller 48 as shown in FIG. 1, and the pure fuel circulation loop and the emulsion fuel circulation loop can be operated individually. It is configured.

In this embodiment, an on-off valve 41 for pure fuel is provided in the fuel return line 26 of the fuel circulation loop, and an emulsion circulation pump 43 and an emulsion pump 43 are provided in the emulsion fuel return line 46 of the emulsion fuel circulation loop. A fuel on-off valve 42 is provided.

When the fuel circulation loop is operated (when water is not added) by the control signal of the controller 48, the pure fuel on-off valve 41 is kept open and the mixer 45 is kept inoperative. On the other hand, when operating the emulsion fuel circulation loop (when adding water), the pure fuel on-off valve 41 is used.
Is closed, the emulsion circulation pump 43 is activated, the emulsion fuel on-off valve 42 is opened, and the mixer 45 is activated. At this time, the pure fuel circulation loop and the emulsion fuel circulation loop passing through the pure fuel return line 66 can be operated individually, so that the emulsion fuel circulation loop can be operated without negative pressure or abnormal pressure increase.

Further, in the present embodiment, unlike the conventional one shown in FIG. 6, a pure fuel flow meter 44 is disposed before a junction 47 into the emulsion fuel circulation loop in the fuel circulation loop. I have. The operation state of the mixer 45, which is the emulsion fuel forming means, is controlled based on the detection signal of the pure fuel flow meter 44. As a result, the accuracy of measuring the amount of fuel consumed by the engine is improved, and the operation state of the mixer 45, which is the emulsion fuel forming means, can be controlled with high accuracy.

Further, the pure fuel between the position outside the emulsion fuel circulation loop in the fuel circulation loop and before the junction 47 to the emulsion fuel circulation loop and the vicinity of the downstream position of the pure fuel on-off valve 41. The return line 66 is provided with a sub-pressure regulating valve 40 which is a pressure regulating means which is set at a higher pressure than the pressurizing and circulating pressure regulating valve 30 which is a main pressure regulating valve in the fuel injection zone 3.

Next, a standard configuration example of a water injection control mechanism for producing an emulsion fuel will be described with reference to FIG. The ratio setting device 57 which receives the signal from the transmission type pure fuel flow meter 44 for measuring the fuel consumption of the engine, based on the water content setting value previously held therein, sends a target water amount to the water amount controller 56. Is output. Water flow controller 56
Receives the signal from the water flow meter 54, adjusts the opening of the water amount control valve 53 so that the set water amount is obtained, and checks the check valve 5
The water is supplied to the mixer 45 via the mixer 5.
In FIG. 2, reference numeral 50 denotes a water tank, reference numeral 51 denotes a filter, and reference numeral 52 denotes a pump.

Next, the operation of the above embodiment will be described with reference to FIG. The pressurized circulation outlet pipe 25 is provided in the fuel injection zone 3.
The pure fuel supplied via the circulates through the fuel circulation loop as follows during non-hydration time (including during operation preparation).

[Non-hydrating operation through the fuel circulation loop]
The sub-pressure regulating valve 40 installed at the inlet of the fuel injection zone 3 is regulated at a higher pressure than the pressurized circulating pressure regulating valve 30. Therefore, the sub-pressure regulating valve 40 normally does not circulate in this state, and the entire amount of pure fuel is Via the fuel flow meter 44, the mixer 4
5, via the pressurized circulation return pipe 32 and the pressurized circulation pressure regulating valve 30 to reach the pressurized circulation return pipe 33. At the same time, fuel is supplied to the injection pump 31 via the branch pipe.

In this state, the controller 48 opens the pure fuel on-off valve 41, and the amount of fuel not consumed by the engine passes through the pure fuel on-off valve 41, passes through the fuel return line 26, The flow is rectified by the pulsation damper 20 and returns to the suction side of the pressurized circulation pump 21. At this time, if the detection signal of the transmission type pure fuel flow meter 44 is sent to the water injection control mechanism in this state, an interlock is provided so as not to output to the water injection control mechanism because the water addition rate increases. .

At this time, the emulsion circulation pump 4
3 is stopped, and the emulsion fuel on-off valve 42 is normally closed. However, in order to equalize the temperature of the emulsion fuel return line 46, the emulsion circulation pump 43 may be operated and the emulsion fuel on-off valve 42 may be opened. In this case, according to the capacity of the emulsion circulation pump 43, the fuel can be circulated from the pressurized circulation return pipe 33 side to the pressurized circulation outflow pipe 32 through the emulsion fuel return line 46.

The pure fuel on-off valve 41 and the emulsion fuel on-off valve 42 are usually automatic valves that can be opened and closed by the force of electricity, air, or the like. A check valve attached in a direction that blocks the flow from the going pipe 32 to the pressurized circulation return pipe 33 can be used instead.

Next, the operation of adding water to the mixer 45, which is an emulsion fuel forming means, to form an emulsion fuel and using the emulsion fuel to pass through an emulsion fuel circulation loop will be described.

[Operation at the time of water addition through the emulsion fuel circulation loop]
Closes the pure fuel on-off valve 41, the pressure of the pressurized circulation outflow pipe 32 rises, and the sub-pressure regulating valve 40 starts pressure regulation. Therefore, only the fuel consumed by the engine passes through the transmission type pure fuel flow meter 44,
By sending a flow rate signal to the water injection control mechanism shown in FIG. 2 in this state, conditions for performing proportional water injection are set. Simultaneously, by operating the emulsion circulation pump 43 and opening the emulsion fuel on-off valve 42, an emulsion fuel circulation loop is formed and preparation for emulsification is completed.

The water and the fuel supplied from the proportional water injection system including the water tank 50 are mixed by the mixer 45 to become an emulsion fuel. This emulsion fuel reaches the pressurized circulation return pipe 33 via the pressurized circulation return pipe 32, but since the pure fuel on-off valve 41 is closed, the entire surplus fuel is sucked into the emulsion circulation pump 43. Via the emulsion fuel on-off valve 42, the emulsion confluence point 4
7 is established.

The emulsion circulation pump 43 is
A positive displacement pump is mainly used. If the discharge capacity of this pump is appropriate for the line, the pressure of the pressurized circulation outgoing pipe 32 is determined by the sub-pressure regulating valve 40. The pressure of the circulation return pipe 33 is a pressure obtained by subtracting the relief pressure of the pressurized circulation pressure regulating valve 30 from this pressure.

In addition, as the emulsion circulation pump 43, a centrifugal pump or a cascade pump having a discharge pressure smaller than the relief pressure of the pressurized circulation pressure regulating valve 30 can be used. Regardless of which pump is used, the absolute pressure of the pressurized circulation outgoing pipe 32 is determined by the sub-pressure regulating valve 40, so there is no possibility that the pressure will become excessive, and the conventional engine specifications will be greatly reduced. No need to change.

[Embodiment 2] FIG. 3 is a block diagram showing another embodiment of the present invention. In the second embodiment, a pure fuel flow meter 44 is disposed on a line (booster outlet pipe) 14 just before a junction from the fuel booster zone 1 to the fuel circulation loop. The operation state of the mixer 45 as the emulsion fuel forming means is controlled based on the detection signal. Other configurations are the same as those of the first embodiment shown in FIG. 1, and therefore, the same portions are denoted by the same reference characters and description thereof is omitted.
Note that some of the controllers 48 and the like are not shown.

According to the second embodiment, the pure fuel flow meter 4
4 is disposed in the line 14 just before the junction from the fuel booster zone 1 to the fuel circulation loop, so that the pure fuel on-off valve 41 provided in the fuel return line 26 is provided.
The flow rate of the pure fuel flow meter 44 can be measured without being affected by the opening and closing of the fuel cell. Therefore, it is possible to always measure the fuel flow rate corresponding to the consumption of the engine, and it is possible to obtain an effect that stable control is easily performed.

[Embodiment 3] FIG. 4 is a structural view showing still another embodiment of the present invention. In the third embodiment, the pure fuel temperature sensor 60 is located at a position outside the emulsion fuel circulation loop in the fuel circulation loop and between the junction point 47 to the emulsion fuel circulation loop and the heater 22. It is arranged. A water temperature sensor 61 is provided in the line for feeding water to the mixer 45, which is the emulsion fuel forming means, at a position downstream of the water temperature variable section 63 as shown in the figure. And the computing unit 65
Thus, the water temperature variable section 63 is driven and controlled in such a direction that the detected water temperature of the water temperature sensor 61 matches the detected fuel temperature of the pure fuel temperature sensor 60.

In actual operation, heating of the pure fuel is performed in order to keep the viscosity of the pure fuel at a constant value. In this case, it is necessary to appropriately change the temperature depending on the properties of the pure fuel. In the present embodiment, since water is added to the heated pure fuel when forming the emulsion fuel, the temperature of the heated pure fuel is set to a set value, and the temperature of the added water is set to the pure fuel. By making the temperature equal to the temperature (set value), even if the fuel temperature changes according to the change of the fuel property, it is possible to automatically form an emulsion fuel keeping the target temperature.

In this embodiment, the emulsion fuel temperature sensor 62 is provided in the emulsion fuel circulation loop. In this example, it is provided between the mixer 45 and the pressurized circulation outflow pipe 32. Then, in a direction in which the detected fuel temperature of the emulsion fuel temperature sensor 62 matches the detected fuel temperature of the pure fuel temperature sensor 60, a water temperature variable section 63 provided in a line for sending water to the emulsion fuel forming means is provided. It is configured to drive control. Other configurations are the same as those of the first embodiment shown in FIG. 1, and therefore, the same portions are denoted by the same reference characters and description thereof is omitted.
Note that some of the controllers 48 and the like are not shown.

In the case of an engine using fuel such as heavy fuel oil C, a fuel oil viscosity measuring device usually called a viscosity sensor is provided at the outlet of the heater 22, and the temperature of the heater outlet is often adjusted by this signal. In such a case,
Since the temperature automatically changes depending on the properties of the heavy oil, ignoring this temperature and keeping the water addition temperature constant may cause a problem.

By measuring the heavy oil temperature with the pure fuel temperature sensor 60, it is possible to know how many times the current target temperature is. When the engine load is large, the heat generation of the emulsion fuel circulation system of the present invention is negligible. Therefore, by setting the water temperature to the same temperature as this, it is possible to send the emulsion fuel having an appropriate viscosity to the engine. Can be done.

However, when the engine load is light, the fuel consumption is reduced, so that the heat generated in the emulsion fuel circulation system may increase the line temperature. In addition, depending on the heat radiation design of the piping, it is also conceivable that the temperature may be reduced. In such a case, the emulsion fuel temperature is measured by the emulsion fuel temperature sensor 62, and the measured value is sent to the mixer 45 as the emulsion forming means so that the measured value becomes the same as the measured value of the pure fuel temperature sensor 60. By controlling the water injection temperature, stable temperature control can be realized even at a light load.

Further, the viscosity of the emulsion fuel at the same temperature tends to be higher than that of the pure fuel. Since the viscosity change of the emulsion fuel shows non-Newtonian properties, the viscosity drops sharply under conditions of large shearing force and tends to approach the viscosity of pure fuel, so temperature control that matches the result of static viscosity measurement is Not required.

However, depending on the injection system of the engine, the temperature of the emulsion fuel may be set slightly higher than, for example, the pure fuel. The temperature of the emulsion fuel at this time is generally confirmed experimentally by measuring the pressure of a high-pressure pipe of the engine or the like.

In this case, the temperature of the emulsion fuel corresponding to the water addition rate is set in advance in the computing unit 65, and the actual set water temperature or emulsion fuel temperature is compared with the water addition rate instruction signal. Temperature sensor for fuel 6
By controlling the set value up and down with respect to 0, the optimum temperature setting can be automatically performed.
As the computing unit 65, one that performs PID control, ON / OFF control, fuzzy control, or the like can be used.

Normally, heating is performed by steam. In this case, the output of the arithmetic unit 65 is output to the steam control valve 64 for water heating, and the feedback of the temperature of the control object is taken, and the water temperature of the heat exchanger is controlled. The steam is supplied to the variable section 63. In addition, in the water injection control mechanism of the emulsion fuel forming means, since the amount of water greatly changes according to the load fluctuation of the engine, a water amount signal is input to the arithmetic unit 65 as necessary, and the flow rate change on the non-heating side is performed. It is also possible to adopt a control method that can respond immediately to the above. In the case of a small-scale apparatus, equipment that heats with an electric heater or heat exchanges with cooling water or the like when cooling is required may be used.

[0062]

According to the present invention, the communication between the fuel circulation loop and the emulsion fuel circulation loop is switched by the controller so that the pure fuel circulation loop and the emulsion fuel circulation loop can be operated separately. At the same time, since the internal volume of the emulsion fuel circulation loop is formed smaller than the internal volume of the fuel circulation loop, the amount of fuel to be emulsified is reduced as compared with the conventional structure, and the fuel is hydrated. The rate can be changed in a short time, and a highly responsive emulsion fuel supply device can be realized. In addition, since the fuel circulation loop is operable separately from the emulsion fuel circulation loop, especially in the case of a medium to large engine,
Heat can be forcibly circulated by the pressurized circulation pump so that heat does not stay in the injection pump, and the heater and the filter can stabilize the temperature of the pure fuel and remove the staying air before starting.

The filter and the pressurizing means or the heating means disposed in the fuel circulation loop are arranged so as to be located outside the emulsion fuel circulation loop. Since there is no conventional filter, heating means, etc., the problem of the stagnation phenomenon is almost eliminated, and the change of the water addition rate of the fuel can be further smoothly performed in a short time.

That is, since the buffer of the emulsion fuel (the amount of fuel consumed when changing the water addition rate) was reduced, the time until the stabilization after the start of water addition and the stop time for drainage were greatly reduced. . In addition, there was no fear of water separation in the heater and the filter, and the maintainability was greatly improved.

In the case of heavy fuel oil C operation, it was expected that the fuel temperature management would be complicated by this method. However, this method can automatically maintain the optimum emulsion fuel temperature, so that the number of buffers is reduced. The adverse effects of this have been eliminated.

The NOx reduction of a diesel engine using an emulsion fuel is effective because it can be applied without significant modification to the fuel injection system conventionally used, and is expected to have an effect not only on NOx reduction but also on dust. However, it has been pointed out that the switching time is long and the maintainability of the heater and the filter is pointed out, which has been an obstacle to practical use. It is believed that the present invention can contribute to improving the global environment by eliminating these obstacles.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an emulsion fuel supply device for a diesel engine according to a first embodiment of the present invention.

FIG. 2 is a standard configuration diagram of a water injection control mechanism for producing an emulsion fuel.

FIG. 3 is a configuration diagram illustrating an emulsion fuel supply device for a diesel engine according to Embodiment 2 of the present invention.

FIG. 4 is a configuration diagram showing an emulsion fuel supply device for a diesel engine according to Embodiment 3 of the present invention.

FIG. 5 is a diagram showing an example of a basic configuration of a normal diesel engine.

6 is a diagram in which an emulsion fuel forming means is provided in the diesel engine shown in FIG.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 37/00 341 F02M 37/00 341H 37/22 37/22 Z 43/00 43/00 55/00 55 / 00 CD 55/02 350 55/02 350C 350E 350U (72) Inventor Koji Yamamoto 1-9-18 Kaigan, Minato-ku, Tokyo Nabuco Tokyo Branch Office F-term (reference) 3G066 AA07 AA16 AB02 AB03 AB08 AC01 BA12 BA19 BA25 CB07U CB15 CB16 CC01 CD22 CD25 CD26 CE22 DC11 DC14 DC15

Claims (8)

[Claims] 1. A pure fuel supply source, a pressurizing means for pressurizing fuel sent from the pure fuel supply source, a fuel injection unit for injecting a part of the pressurized fuel into a cylinder of an engine, A fuel circulation loop passing through a fuel return line for returning the remaining fuel not injected by the fuel injection unit to the suction side of the pressurizing means, wherein the fuel injection in the fuel circulation loop is performed. An emulsion fuel forming means provided in front of a fuel inflow portion into the section, an emulsion fuel return line branched from the fuel return line and communicating with a position near the suction side of the emulsion fuel forming means, and the fuel injection section. An emulsion fuel circulation loop formed to be smaller than the internal volume of the fuel circulation loop; and the emulsion fuel in the fuel circulation loop Pure fuel circulation through a pure fuel return line provided before the junction with the return line and downstream of a branch point of the emulsion fuel return line, and a pressure adjusting means provided in the pure fuel return line A controller for switching the communication between the fuel circulation loop and the emulsion fuel circulation loop. The pure fuel circulation loop and the emulsion fuel circulation loop are formed so as to be capable of being independently circulated by switching the controller. An emulsion fuel supply device for a diesel engine. 2. The diesel engine according to claim 1, wherein the filter and / or the heating means disposed in the fuel circulation loop are arranged outside the emulsion fuel circulation loop. Emulsion fuel supply system. 3. The pure fuel on-off valve according to claim 1, wherein a pure fuel on-off valve is provided between a branch point of the fuel return line with the emulsion fuel return line and a junction of the pure fuel return line. An emulsion circulation pump and an emulsion fuel on-off valve are provided in the emulsion fuel return line of the fuel circulation loop. The pure fuel on-off valve is opened when the operation with pure fuel is performed by a control signal of the controller. State and the emulsion fuel forming means is kept in a non-operating state. When the operation with the emulsion fuel is performed, the pure fuel on-off valve is closed, and the emulsion circulation pump is in an operating state and the emulsion circulation pump is operated. The on-off valve for fuel is configured to be opened and the emulsion fuel forming means is configured to be operated. An emulsion fuel supply device for a diesel engine. 4. The pure fuel flow meter according to claim 1, wherein a pure fuel flow meter is provided at a position for supplying fuel from the fuel circulation loop to the emulsion fuel circulation loop. An emulsion fuel supply device for a diesel engine, wherein the amount of water in the emulsion fuel forming means is controlled based on a detection signal. 5. The pure fuel flow meter according to claim 1, wherein a pure fuel flow meter is provided in a supply line from the pure fuel supply source to the fuel circulation loop, and a detection signal of the pure fuel flow meter is provided. Wherein the amount of water in the emulsion fuel forming means is controlled based on the emulsion fuel supply means. 6. The pressure adjusting device according to claim 1, wherein the pressure adjusting means provided in the pure fuel return line for forming the pure fuel circulation loop is provided in a fuel circulation loop. An emulsion fuel supply device for a diesel engine, characterized by using a sub-pressure regulating valve set at a higher pressure than the main pressure regulating valve. 7. The heating device according to claim 1, wherein the heating device is located outside the emulsion fuel circulation loop and between a junction of the emulsion fuel return line in the fuel circulation loop and the heating means. A temperature sensor for pure fuel is provided, and a water temperature sensor is provided in the line for sending water to the emulsion fuel forming means and at a position downstream of the water temperature variable section. An emulsion fuel supply device for a diesel engine, wherein a drive control of the water temperature variable section is performed in a direction in which a water temperature detected by the water temperature sensor coincides. 8. The heating apparatus according to claim 1, wherein the heating means is located outside the emulsion fuel circulation loop and between a junction of the emulsion fuel return line in the fuel circulation loop and the heating means. A temperature sensor for pure fuel is disposed in the emulsion fuel circulation loop, and a direction in which the temperature detected by the emulsion fuel temperature sensor matches the temperature detected by the temperature sensor for pure fuel. An emulsion fuel supply device for a diesel engine, which is configured to drive and control a water temperature variable section provided in a line for sending water to the emulsion fuel forming means.