JP6913270B2 - Fuel injection device for internal combustion engine using low ignitability fuel - Google Patents

Description

The present invention relates to a fuel injection device for operating an internal combustion engine using a low ignitable fuel.

Conventionally, for example, marine teazel engines have used so-called fuel oil such as heavy oil as the main fuel for many years. The reason is that fuel oil is relatively inexpensive and has the necessary conditions for ships that it can be procured in large quantities anywhere.

On the other hand, in recent years, a clean energy source has been demanded especially from the viewpoint of global environmental protection, and a significant reduction in CO2, SOX, NOX and other emissions has become an urgent issue. In particular, reduction of CO2 and SOX emissions is naturally required for marine diesel engines, so it is possible that regulations based on international regulations will be tightened, and gas that uses gas fuel such as natural gas and LNG as the main fuel. The development of engines is rapidly becoming widespread (see, for example, Patent Document 1).

Further, these gas fuels are classified as so-called low ignitable fuels, and the low ignitable fuels also include methanol. Since this methanol does not contain sulfur in its fuel, it does not emit SOX, which is an air pollutant, even when burned. In addition, since the amount of CO2 and particulate matter emitted per unit calorific value is smaller than that of fuel oil, which is a conventional marine fuel, it is expected to be one of the next-generation clean fuels.

Furthermore, while methanol production has been mainly refined from petroleum, there are many plans for coal-derived methanol refining plants, while methanol produced from inexpensive natural gas is cheaper than ever. Moreover, since it has the potential to be mass-produced, there is room for methanol as a fuel for marine diesel engines in terms of supply.

Under such circumstances, the applicant of the present application has developed a secondary fuel diesel engine capable of using a low ignitable fuel typified by methanol together with a fuel oil which is a conventional marine fuel (see, for example, Patent Document 2). .. This secondary fuel diesel engine has a dedicated secondary fuel injection pump and secondary fuel injection valve for injecting secondary fuel, in addition to the conventional fuel injection pump and fuel injection valve for injecting fuel oil. Each is additionally equipped separately.

Then, through the fuel injection valve for the fuel oil and the secondary fuel injection valve for the secondary fuel, the fuel to be used is selectively selected according to the operating state of the engine at that time, and 100 It is operated with either% fuel oil or 100% secondary fuel. Since the secondary fuel cannot obtain stable ignition only by raising the temperature due to the compression of the piston, in the pilot ignition type engine, the fuel oil that can be easily ignited is pilot-injected from the pilot fuel injection valve, and the secondary fuel is injected. Form a fire for burning fuel.

As a result, compared to a conventional engine that uses only fuel oil, this secondary fuel diesel engine has no problems related to knocking or emission of unburned fuel, and its combustion characteristics do not depend on the properties of the secondary fuel. Even when operating with only secondary fuel, it is possible to sufficiently achieve the same engine output and load fluctuation tracking as when operating with fuel oil.

Japanese Unexamined Patent Publication No. 2012-177333

Mitsui Engineering & Shipbuilding Technical Report No. 218 "Completion of the World's First Methanol-Fired ME-LGI Institution", pp. 1-5, published January 30, 2017, by Takahiro Murakami

As described above, in an internal combustion engine using a low ignitable fuel typified by conventional methanol, in order to inject a secondary fuel in addition to the conventional fuel injection pump and fuel injection valve for fuel oil. The dedicated secondary fuel injection pump and secondary fuel injection valve are additionally equipped separately, and the operation of the engine at that time is performed through the fuel injection valve for fuel oil and the secondary fuel injection valve for secondary fuel. The fuel is selectively selected according to the condition and is operated by either 100% fuel oil or 100% secondary fuel.

However, in this way, in addition to the fuel injection pump and fuel injection valve for fuel oil up to that point, a dedicated secondary fuel injection pump and secondary fuel injection valve for secondary fuel are additionally equipped. Then, it is necessary to equip two fuel injection devices having a complicated structure around the engine in which auxiliary machinery is arranged in a complicated manner, which may make it difficult to arrange the fuel injection devices.

The present invention has been made to solve such a problem, and provides a fuel injection device for an internal combustion engine using a low ignitable fuel, which has an extremely simple structure of a fuel injection device and facilitates equipment arrangement. That is the issue.

In order to solve the above-mentioned problems, the means adopted by the present invention is a fuel injection device for an internal combustion engine using a low ignitable fuel, and a fuel oil supply unit for supplying the fuel oil and a low ignitable fuel are used. A fuel mixing unit that produces a mixed fuel by mixing a low ignitable fuel supply unit to be supplied, a fuel oil supplied from the fuel oil supply unit, and a low ignitable fuel supplied from the low ignitable fuel supply unit. It is provided with a fuel injection unit which is arranged in the internal combustion engine and injects the mixed fuel supplied from the fuel mixing unit into the cylinder of the internal combustion engine. The above-mentioned fuel oil means, for example, gasoline or light oil, A heavy oil, C heavy oil, etc., and the above-mentioned low ignitable fuel means, for example, LPG (liquefied petroleum gas) or methanol, ethanol, dimethyl ether or the like.

As described above, the fuel injection device of the internal combustion engine using the low ignitable fuel of the present invention mixes the fuel oil supplied from the fuel oil supply section and the low ignitable fuel supplied from the low ignitable fuel supply section. Since it is provided with a fuel mixing section for generating the mixed fuel and a fuel injection section for injecting the mixed fuel supplied from the fuel mixing section into the cylinder of the internal combustion engine, it is similar to a conventional secondary fuel diesel engine. It is not necessary to individually double-equip a fuel injection device having a complicated structure consisting of two systems of fuel oil and low ignitability fuel around an engine in which auxiliary machinery and the like are arranged in a complicated manner. Therefore, the structure of the fuel injection device becomes extremely simple, and the equipment arrangement becomes easy.

In the fuel injection device of an internal combustion engine using the low ignitable fuel, it is desirable to further include a mixed fuel separation unit for separating the fuel oil in the mixed fuel and the low ignitable fuel. In this way, by providing the mixed fuel separation unit that separates the fuel oil in the mixed fuel and the low ignitable fuel, the fuel oil in the mixed fuel and the low ignitable fuel once mixed can be re-separated. Each can be stored or used independently.

Further, the mixed fuel separation unit separates the mixed fuel that is not injected into the cylinder from the fuel injection unit into the fuel oil and the low ignitability fuel, and the fuel oil separated from the mixed fuel is returned to the fuel oil supply unit. Alternatively, the low ignitable fuel separated from the mixed fuel is more preferably returned to the low ignitable fuel supply section.

In this way, of the mixed fuel supplied from the fuel mixing section to the internal combustion engine, the surplus mixed fuel that is not injected into the cylinder from the fuel injection section of the internal combustion engine has low ignitability with the fuel oil by the fuel separating section. Separated from fuel. Then, the fuel oil separated from the mixed fuel is returned to the fuel oil supply section, or the low ignitable fuel separated from the mixed fuel is returned to the low ignitable fuel supply section. Either or both of the fuel oil in the mixed fuel and the low ignitability fuel that have not been injected into the cylinder are used for combustion of the internal combustion engine without waste.

In the fuel injection device of an internal combustion engine using the low ignitable fuel, it is desirable that the low ignitable fuel is supplied to the fuel injection portion of the internal combustion engine in a liquid phase state. In this way, the low ignitable fuel is supplied to the fuel injection section of the internal combustion engine in a liquid phase state, so that the low ignitable fuel in the mixed fuel is kept in the cylinder of the internal combustion engine while maintaining its combustion characteristics. It is injected into and properly burned.

In the fuel injection device of an internal combustion engine using the low ignition fuel, it is desirable that the internal combustion engine is operated in a diesel cycle.

The internal combustion engine is mainly operated by a diesel cycle and an Otto cycle. As will be described in detail later, the former diesel cycle has a feature of excellent thermal efficiency because the injected fuel is completely burned, while the latter Otto cycle has a part of the unburned fuel together with the combustion gas. Since it is discharged to the outside of the engine, there is a problem that the thermal efficiency is inferior. In the fuel injection device of an internal combustion engine using the above-mentioned low ignitable fuel, there is a problem related to the emission of unburned fuel due to the operation in the diesel cycle using the above-mentioned mixed fuel of the fuel oil and the low ignitable fuel. It is excellent in thermal efficiency, knocking does not occur, and the engine output and the ability to follow load fluctuations, which are almost the same as those of an internal combustion engine using conventional fuel oil, are ensured.

In the fuel injection device of an internal combustion engine using the low ignitability fuel, it is desirable that the internal combustion engine does not have a pilot fuel injection valve.
Since the above-mentioned mixed fuel is a mixture of a low ignitable fuel having poor ignitability and a fuel oil having good ignitability, it is possible to eliminate the pilot fuel injection required for a conventional secondary fuel diesel engine. .. In this case, it is not necessary to separately equip a fuel oil supply unit for pilot injection with fuel oil or the like around the engine, which also simplifies the structure of the fuel injection device and makes the equipment arrangement easier.

In the fuel injection device of an internal combustion engine using the low ignitability fuel, it is desirable that the mixed fuel is constantly injected into the cylinder from the fuel injection portion of the internal combustion engine during the combustion operation of the internal combustion engine.

In this way, the mixed fuel is constantly injected into the cylinder from the fuel injection portion of the internal combustion engine during the combustion operation of the internal combustion engine, so that the fuel oil or the low ignitability fuel such as the conventional secondary fuel diesel engine can be used. All operations by only one of them can be eliminated, the structure of the fuel injection device becomes simpler, and the equipment arrangement becomes easier.

In the fuel injection device of an internal combustion engine using the low ignitable fuel, the fuel mixing section is supplied from the fuel oil supplied from the fuel oil supply section and the low ignitable fuel supply section according to the operating state of the internal combustion engine. It is desirable to be able to change the mixing ratio with the low ignitable fuel.

In this way, the fuel mixing section changes the mixing ratio of the fuel oil supplied from the fuel oil supply section and the low ignitable fuel supplied from the low ignitable fuel supply section according to the operating state of the internal combustion engine. By enabling this, the ignitability to the mixed fuel and other combustion characteristics can be optimally maintained in any operating state of the internal combustion engine.

In the fuel injection device of an internal combustion engine using the low ignitable fuel, it is desirable that the low ignitable fuel is methanol and a water supply unit for containing water in the mixed fuel is further provided. In this way, by using methanol as the low-ignition fuel and further providing a water supply unit for containing water in the mixed fuel, it is possible to lower the combustion temperature in the cylinder of the internal combustion engine during combustion, and NOX. Emissions can be further reduced.

In the fuel injection device of an internal combustion engine using the above-mentioned low ignitable fuel, this water supply unit is connected to the low ignitable fuel supply unit to supply water to the low ignitable fuel supply unit to become a low ignitable fuel. It is more desirable to add water to the mixed fuel by mixing it with water.

In this way, the water supply unit connected to the low ignitable fuel supply unit supplies water to the low ignitable fuel supply unit and mixes the water with the low ignitable fuel in advance, so that the mixed fuel contains water. Water can be easily contained in the mixed fuel.

The fuel injection device for an internal combustion engine using the low ignitability fuel of the present invention is a fuel injection device for an internal combustion engine using the low ignitability fuel, and has a fuel oil supply unit for supplying fuel oil and a low ignitability fuel. A low ignitable fuel supply unit that supplies fuel, and a fuel mixing unit that produces a mixed fuel by mixing the fuel oil supplied from the fuel oil supply unit and the low ignitable fuel supplied from the low ignitable fuel supply unit. Since it is provided with a fuel injection unit that is arranged in the internal combustion engine and injects the mixed fuel supplied from the fuel mixing unit into the cylinder of the internal combustion engine, the structure of the fuel injection device becomes extremely simple and the equipment arrangement becomes easy. It has the excellent effect of being able to do it.

It is a system diagram which shows the fuel injection apparatus using the low ignition fuel of the internal combustion engine of this invention. It is a system diagram which shows the fuel injection device which used the low ignition fuel of an internal combustion engine, which is different from FIG.

A mode for implementing a fuel injection device for an internal combustion engine using a low ignitability fuel according to the present invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 shows the first form. As shown in FIG. 1, the fuel injection device 2 of a large marine diesel engine 1 as an example of an internal combustion engine has a fuel oil supply unit 10 for supplying fuel oil and a low ignitable fuel supply unit for supplying low ignitable fuel. A fuel mixing unit 30 that mixes the fuel oil supplied from the fuel oil supply unit 10 and the low ignitable fuel supplied from the low ignitable fuel supply unit 20 to generate a mixed fuel thereof, and a large marine vehicle. The fuel injection unit 40, which is arranged in the diesel engine 1 and injects the mixed fuel supplied from the fuel mixing unit 30 into the cylinder of the diesel engine 1, separates the fuel oil in the mixed fuel and the low ignitable fuel. It is provided with a mixed fuel separation unit 60 for the purpose.

The above-mentioned fuel oil means, for example, gasoline, light oil, A heavy oil, C heavy oil, etc., and the low ignitable fuel means, for example, LPG (liquefied petroleum gas), methanol, ethanol, dimethyl ether and the like. The low ignitable fuel has lower ignitability than the conventional fuel oils such as gasoline, light oil, A heavy oil, and C heavy oil, and these low ignitable fuels are used alone as the main fuel in large marine diesel engines. In some cases, pilot fuel injection is required, and conventional fuel oil is required as the fuel for this pilot injection.

However, for example, LPG and methanol, which are low-ignitability fuels, have similar polarities to heavy fuels such as heavy oil and light oil as fuel oils, and both are well mixed. The fuel injection device 2 utilizes such properties between fuels.

The fuel oil is sent from the fuel oil tank 11 to the electric fuel oil pump 13 via the flow meter 12, and is pressurized here. The fuel oil pressurized by the fuel oil pump 13 is sent to the above-mentioned fuel mixing section 30 via the filter 14, the three-way valve 15, and the check valve 16. By switching the three-way valve 15, the pressurized fuel oil can be returned to the fuel oil tank 11. The overpressured fuel oil that has exited the three-way valve 15 is returned to the fuel oil tank 11 by the operation of the relief valve 19 arranged in the branch path 18 from the three-way valve 15. The fuel oil supply unit 10 described above is formed by these devices.

On the other hand, the low ignitable fuel is sent from the low ignitable fuel tank 21 to the electric low ignitable fuel pump 23 via the flow meter 22, and is pressurized here. The low ignitable fuel pressurized by the low ignitable oil pump 23 is sent to the above-mentioned fuel mixing section 30 via the filter 24 and the check valve 26. The overpressured low ignitable fuel exiting the filter 24 is the low ignitable fuel via the electric booster pump 27 and the check valve 27a by the operation of the relief valve 29 arranged in the branch path 28 from the filter 24. It is returned to the tank 21. The low ignitability fuel supply unit 20 described above is formed by these devices.

The fuel mixing unit 30 determines the mixing ratio of the fuel oil supplied from the fuel oil supply unit 10 and the low ignitable fuel supplied from the low ignitable fuel supply unit 20 according to the operating state of the large marine diesel engine 1. Can be changed.

For example, an engine controller (not shown) controls the operation of the fuel oil pump 13 and the low ignitable oil pump 23 based on the flow values of the flow meters 12 and 22, and changes the discharge flow rate of the fuel oil pump 13 to change the discharge flow rate of the fuel oil mixing unit. It is possible to change the mixing ratio of the fuel oil and the low ignitability fuel in 30. Further, the fuel mixing unit 30 itself may be provided with a function capable of changing the mixing ratio of the fuel oil and the low ignition fuel by controlling an engine controller (not shown).

In this way, the mixing ratio of the fuel oil supplied from the fuel oil supply unit 10 and the low ignitable fuel supplied from the low ignitable fuel supply unit 20 is changed according to the operating state of the large marine diesel engine 1. By allowing the diesel engine 1, the ignitability and other combustion characteristics can be optimally maintained in any operating state of the diesel engine 1.

The mixed fuel of the fuel oil and the low ignitability fuel that has exited the fuel mixing section 30 is supplied to the fuel pump 42 of the large marine diesel engine 1 via the check valve 41, and the injection pressure required by the fuel pump 42 is increased. Pressurization is adjusted. The mixed fuel pressurized to the required injection pressure by the fuel pump 42 is injected into the cylinder of the diesel engine 1 via the fuel injection valve 43. The fuel injection section 40 is formed by the fuel pump 42 and the fuel injection valve 43.

In this way, the large marine diesel engine 1 uses a mixed fuel of fuel oil and low ignitability fuel, so that a certain level of ignitability is ensured, and even if pilot injection is not performed, the large marine diesel engine 1 uses only conventional fuel oil. Ignition performance comparable to that of diesel engines can be obtained. The diesel engine 1 is operated in a diesel cycle using a mixed fuel of fuel oil and a low ignitability fuel under the control of an engine controller (not shown).

The internal combustion engine is mainly operated by a diesel cycle and an Otto cycle. The former diesel cycle injects fuel into compressed air and self-ignites in the combustion chamber where the fuel becomes hot due to the compression process. Therefore, the injected fuel is completely burned and has a feature of excellent thermal efficiency.

On the other hand, in the latter Otto cycle, heat is generated by injecting fuel into the combustion chamber in the compression process and igniting the fuel near top dead center. In this Otto cycle, the fuel injected into the combustion chamber may not be completely burned, and the unburned fuel may remain in the combustion chamber. Therefore, there is a problem that the unburned residue of the fuel is discharged to the outside of the engine together with the exhaust gas, resulting in inferior thermal efficiency.

In the above-mentioned large marine diesel engine 1, since it is operated in a diesel cycle using a mixed fuel of fuel oil and low ignitable fuel, there is no problem related to the emission of unburned fuel, the thermal efficiency is excellent, and knocking occurs. It does not occur, and the engine output and the ability to follow load fluctuations, which are almost the same as those of a conventional internal combustion engine using fuel oil, are ensured.

Further, the mixed fuel of the fuel oil and the low ignitability fuel that has left the above-mentioned fuel mixing unit 30 is sent to the mixed fuel separation unit 60 via the relief valve 61. In the mixed fuel separation unit 60, among the mixed fuels supplied from the fuel mixing unit 30 to the large marine diesel engine 1, the mixed fuels that were not injected into the cylinder from the fuel injection valve 43 are the fuel oil and the low ignitability fuel. Is separated into.

The fuel oil separated by the mixed fuel separation unit 60 is returned to the fuel oil tank 11 via the branch path 18 on the downstream side of the relief valve 19 of the fuel oil supply unit 10. Further, the low ignitable fuel separated by the mixed fuel separation section 60 is returned to the low ignitable fuel tank 21 via a branch path 28 on the downstream side of the relief valve 29 of the low ignitable fuel supply section 20.

As described above, the mixed fuel of the fuel oil and the low ignitability fuel is supplied to the fuel injection valve 43 in the liquid phase state, and is injected from these fuel injection valves 43 and 53 into the cylinder of the large marine diesel engine 1. NS. That is, the low ignitable fuel forming a part of the mixed fuel is supplied to the fuel injection valve 43 not only in the low ignitable fuel tank 21 but also in the fuel mixing section 30 while maintaining the liquid phase state. NS.

Further, in the large marine diesel engine 1, a mixed fuel of fuel oil and low ignitable fuel is constantly injected into the cylinder via the fuel injection valve 43 during combustion operation, that is, in all combustion operation states. ..

When the low ignitability fuel is methanol or ethanol, it is in a liquid phase state at normal temperature and pressure, so no special device is required to maintain the liquid phase state up to the fuel injection valve 43. On the other hand, when the low ignitability fuel is LPG or dimethyl ether, it is necessary to apply a constant pressure to maintain the liquid phase state up to the fuel injection valve 43.

For example, in LPG, it is necessary to maintain a pressure of about 20 bar or less at 45 ° C. Further, the supply pressure of the fuel oil supplied from the fuel oil supply unit 10 and the supply pressure of the low ignitable fuel supplied from the low ignitable fuel supply unit 20 are the relief valve 19 of the fuel oil supply unit 10 and low ignition. It is adjusted to about the same level by the sex fuel supply unit 29.

Since the above-mentioned mixed fuel is a mixture of a low ignitable fuel having poor ignitability and a fuel oil having good ignitability, the ignitability is significantly improved as compared with the case where only the low ignitable fuel is used. Therefore, in the present fuel injection device 2 as an example, the pilot fuel injection valve is not provided and the pilot fuel injection is not performed.

FIG. 2 shows the second form. In addition, only the difference from the first form shown in FIG. 1 described above will be described. In this fuel injection device 3, for example, when the low ignitable fuel is methanol, water is mixed in advance with the low ignitable fuel methanol, and the fuel injection valve 40 of the large marine diesel engine 1 is inside the cylinder. A water supply unit 70 for containing water in the mixed fuel injected into the fuel is provided.

The water supply unit 70 includes a water tank 71 and a water pump 72, and the water supply path 73 whose pressure is increased to a constant pressure by the water pump 72 has low ignitability between the low ignitability fuel pump 23 and the filter 24. It is connected to the fuel supply path (low ignitable fuel supply section) 23a, and water having a constant pressure is supplied to the low ignitable fuel supply path 23a.

In this case, the low ignitable fuel is methanol as an example, whereas methanol has a CH group and an OH group in one molecule, so that it mediates between fuel oil such as heavy oil and water like a sea surface activator. It forms a micelle with these and becomes an emulsified form. Therefore, water can be easily contained in the mixed fuel.

By including water in the mixed fuel in this way, the combustion temperature in the cylinder of the large marine diesel engine 1 can be lowered at the time of combustion, and the NOX emission amount can be further reduced. Others are the same as the fuel injection device 2 of the internal combustion engine using the low ignition fuel of the first embodiment described above, and thus the description thereof will be omitted.

As described above, the fuel injection devices 2 and 3 of the internal combustion engine using the low ignitable fuel have the fuel oil supplied from the fuel oil supply unit 10 and the low ignition supplied from the low ignitable fuel supply unit 20. A fuel injection unit having a fuel mixing unit 30 that mixes with a sex fuel to generate a mixed fuel, and injecting the mixed fuel supplied from the fuel mixing unit 30 into the cylinder of a large marine diesel engine 1 as an example. Since the 40 is provided, it is not necessary to separately double-equip a fuel injection device having a complicated structure consisting of two systems of fuel oil and low ignitable fuel around the engine as in the conventional secondary fuel diesel engine. Therefore, the fuel injection devices 2 and 3 of the internal combustion engine using the low ignitability fuel have an extremely simple structure, and the equipment arrangement is easy.

Further, since the above-mentioned mixed fuel is a mixture of low ignitable fuel having poor ignitability and fuel oil having good ignitability, pilot fuel injection required for a conventional secondary fuel diesel engine from the viewpoint of ignitability Can also be eliminated. Therefore, it is not necessary to separately equip a fuel oil supply unit for pilot injection with fuel oil or the like around the engine, which also simplifies the structure of the fuel injection device and facilitates the arrangement of equipment.

On the other hand, among the mixed fuels supplied from the fuel mixing unit 30 to the fuel injection unit 40, the surplus mixed fuel that is not injected into the cylinder from them is the fuel oil and the low ignitability fuel by the mixed fuel separation unit 60. Is separated into. Then, the fuel oil separated by the mixed fuel separation unit 60 is returned to the fuel oil supply unit 10, and the low ignitable fuel separated by the mixed fuel separation unit 60 is returned to the low ignitable fuel supply unit 20. Therefore, the surplus fuel oil and the low ignitability fuel in the mixed fuel are used without waste for the fuel injection of the large marine diesel engine 1.

Further, since the low ignitable fuel is supplied to the fuel injection unit 40 in the liquid phase state, the low ignitable fuel in the mixed fuel is injected into the cylinder of the internal combustion engine while maintaining its combustion characteristics. And it is burned properly.

Further, as described above, the mixed fuel is constantly injected from the fuel injection unit 40 into the cylinder of the large marine diesel engine 1, so that the fuel oil or the low ignitability fuel such as the conventional secondary fuel diesel engine can be used. All operations by only one of the alternatives can be eliminated, the structure becomes extremely simple, and the equipment arrangement becomes easier.

The fuel injection device for an internal combustion engine using the above-mentioned low ignitability fuel is only an example, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention. .. For example, the internal combustion engine is not limited to the above-mentioned large marine diesel engine 1, and it goes without saying that it can be implemented for other types of internal combustion engines.

1 Large marine diesel engine 2, 3 Fuel injection device 10 Fuel oil supply unit 11 Fuel oil tank 12 Flow meter 13 Fuel oil pump 14 Filter 15 Three-way valve 16 Check valve 18 Branch path 19 Relief valve 20 Low ignitability fuel supply unit 21 Low ignitable fuel tank 22 Flow meter 23 Low ignitable fuel pump 23a Low ignitable fuel supply path 24 Filter 26 Check valve 27 Boost pump 27a Check valve 28 Branch path 29 Relief valve 30 Fuel mixing section 40 Fuel injection section 41 Reverse Stop valve 42 Fuel pump 43 Fuel injection valve 60 Mixed fuel separation part 61 Relief valve 70 Water supply part 71 Water tank 72 Water pump 73 Supply path

Claims (6)

A fuel injection device (2, 3) of an internal combustion engine (1) using a low ignitable fuel, which is a fuel oil supply unit (10) for supplying fuel oil and a low ignitable fuel for supplying low ignitable fuel. A fuel mixing unit (20) that produces a mixed fuel by mixing the fuel oil supplied from the fuel oil supply unit with the low ignitable fuel supplied from the low ignitable fuel supply unit (20). 30) and a fuel injection unit (40) that is disposed in the internal combustion engine and injects the mixed fuel supplied from the fuel mixing unit into the cylinder of the internal combustion engine, and the internal combustion engine is a pilot fuel. It is a large marine diesel engine that does not have an injection valve and is operated in a diesel cycle. The fuel injection unit constantly injects only the mixed fuel into the cylinder, and the low ignitability fuel in the mixed fuel. Is a fuel injection device using a low ignitable fuel of an internal combustion engine, which is injected into the cylinder in a liquid phase state. And further comprising a mixed fuel separating unit for separating the said fuel oil and said low ignitability fuel in the mixed fuel (60), the internal combustion engine using a low ignitability fuel according to claim 1 Fuel injection device. The mixed fuel separation unit (60) separates the mixed fuel that has not been injected into the cylinder from the fuel injection unit (40) into the fuel oil and the low ignitability fuel, and is separated from the mixed fuel. The fuel oil is returned to the fuel oil supply unit (10), or the low ignitable fuel separated from the mixed fuel is returned to the low ignitable fuel supply unit (20). The fuel injection device for an internal combustion engine using the low ignitability fuel according to claim 2. The fuel mixing unit (30) is supplied from the fuel oil supplied from the fuel oil supply unit (10) and the low ignitability fuel supply unit (20) according to the operating state of the internal combustion engine (1). The fuel injection device using a low ignitable fuel of an internal combustion engine according to any one of claims 1 to 3 , wherein the mixing ratio with the low ignitable fuel can be changed. The low internal combustion engine according to any one of claims 1 to 4 , wherein the low ignitability fuel is methanol, and a water supply unit (70) for containing water in the mixed fuel is further provided. Fuel injection device using ignitable fuel. The water supply unit (70) is connected to the low ignitable fuel supply unit (20) to supply the water to the low ignitable fuel supply unit (20) and mix the water with the low ignitable fuel. The fuel injection device using a low ignitability fuel of an internal combustion engine according to claim 5 , wherein the mixed fuel contains the water.

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