JP2004068776A - Method for operating two fluid injection internal combustion engine and device for injecting two type fluid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for operating a two type fluid injection internal combustion engine and a device for injecting two type fluid capable of well balancing NOx concentration reduction in combustion and engine output increase accompanied with water injection by properly establishing injection quantity and injection timing of water injection before a top dead center and after the top dead center. <P>SOLUTION: In a four cycle two type fluid injection internal combustion engine injecting main fluid and another injection fluid into a combustion chamber and firing the same, the injection fluid is injected with divided into twice before and after combustion top dead center in such a manner that injection quantity ratio between a first injection and a second injection can be changed and that a first injection timing is established to overlap main fuel injection timing. Especially, injection quantity of the second injection is established greater than injection quantity of the first injection. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for operating a four-cycle two-fluid injection internal combustion engine in which main fuel and an injection fluid such as high-temperature water are injected into a combustion chamber and combusted, and a two-fluid injection device for the internal combustion engine.
[0002]
[Prior art]
In a diesel engine, many techniques for directly injecting water into a combustion chamber are provided as means for reducing the amount of NOx (nitrogen oxide) generated in the combustion process in a cylinder of the engine.
In the case of the type in which water is directly injected into the combustion chamber, the water injection is usually performed from the end of the compression stroke to the beginning of the combustion stroke, that is, before the combustion process and / or during the combustion stroke. By adopting such water injection timing, a large amount of water can be injected into the combustion chamber, thereby reducing NOx by about 50 to 60%.
[0003]
In a four-cycle diesel engine, as one of techniques for performing water injection into the combustion chamber as described above from the end of the compression stroke to the beginning of the combustion stroke, there is an invention of Japanese Patent Laid-Open No. 2001-200761.
In this invention, high pressure water having a pressure of 5 MPa or more and a temperature of 250 ° C. or more is applied before and after the top dead center of the engine, preferably at a crank angle in a range of 90 ° before top dead center to 60 ° after top dead center. By injecting the high-pressure water having a temperature lower than the temperature in the combustion chamber into the combustion chamber before the point, the NOx concentration generated by combustion is reduced, and by exhausting the high-pressure water into the combustion chamber after the top dead center, exhaust heat is discharged. The collection effect is improved.
[0004]
[Problems to be solved by the invention]
In the invention of Japanese Patent Laid-Open No. 2001-200761, by injecting high-pressure water before top dead center, the temperature in the cylinder is lowered to reduce NOx concentration, and the high-pressure water is injected after top dead center. By increasing the amount of working fluid in the combustion chamber, the amount of exhaust heat recovered is increased to improve thermal efficiency.
[0005]
However, in this invention, the high-pressure water is simply injected in two steps before the top dead center and after the top dead center. The high-pressure water injection amount before the top dead center and the high-pressure water after the top dead center. The ratio to the injection amount, or the relationship between the high-pressure water injection before the top dead center and the main fuel injection timing, and the relationship between the high-pressure water injection after the top dead center and the main fuel injection end time are clearly indicated. Not.
[0006]
For this reason, in this invention, if the amount of high-pressure water injection before the top dead center becomes excessive, the effect of reducing the NOx concentration due to the temperature drop in the cylinder increases, while the engine output decreases with the decrease in the cylinder maximum pressure. If the amount of high-pressure water injection before the top dead center is too small, the effect of increasing the amount of exhaust heat recovered due to the increase in the amount of working fluid in the combustion chamber will be reduced, and the high-pressure water injection will suppress the combustion promotion effect of the main fuel and The engine thermal efficiency cannot be improved by water injection.
[0007]
Further, in the invention, as described above, since the relationship between the injection timing of the high-pressure water before the top dead center and the injection start timing of the main fuel is not clearly shown, it is caused by the mixing action of the high-pressure water and the main fuel. The injection timing of high-pressure water before top dead center that can achieve a good balance between combustion promotion and NOx concentration reduction cannot be grasped, and the injection timing of high-pressure water and the main fuel injection end timing after top dead center Since the relationship is not clearly stated, it is impossible to grasp the injection timing of high-pressure water that can exert the effect of promoting combustion of main fuel by high-pressure water injection.
And so on.
[0008]
In view of the problems of the prior art, the present invention has a function of reducing NOx concentration during combustion by appropriately setting the injection amount and injection timing of water injection before top dead center and water injection after top dead center. It is an object of the present invention to provide a method for operating a two-fluid injection internal combustion engine capable of exerting a good balance between an increase in engine output accompanying water injection and a two-fluid injection device for the internal combustion engine.
[0009]
[Means for Solving the Problems]
In view of the problems of the prior art, the present invention provides an operation method of a four-cycle two-fluid injection internal combustion engine in which main fuel and another injection fluid are injected into a combustion chamber and combusted. The fluid is divided into two parts before and after the combustion top dead center, and the injection amount ratio between the first injection and the second injection is made variable, and the first injection timing is set as the main fuel injection timing. A method for operating a two-fluid injection internal combustion engine is proposed.
[0010]
The invention of claim 2 is characterized in that, in addition to claim 1, the injection amount of the second injection is set to be larger than the injection amount of the first injection.
[0011]
According to a third aspect of the present invention, in addition to the first aspect, the injection start timing of the second injection is set close to the main fuel injection end timing or overlapped with the main fuel injection end timing. .
[0012]
Further, in claim 1, high temperature water or water vapor is preferably used as the jet fluid as in claim 4, or supercritical water is preferably used as in claim 5.
[0013]
Next, the invention described in claims 6 to 8 relates to an invention of an apparatus used in the operating method according to the inventions of claims 1 to 5, and the invention of claim 6 relates to the main fuel and other injection fluids in the combustion chamber. In a four-cycle two-fluid injection internal combustion engine that injects the fuel into the combustion chamber, an injection valve that injects the injection fluid into the combustion chamber, and a first injection before and after the combustion top dead center from the injection valve A fluid injection device that is divided into two injections, the second injection, and the first injection timing overlaps with the main fuel injection timing, and the injection amount ratio of the two injections is variable and injection is performed. It is characterized by.
[0014]
According to a seventh aspect of the present invention, in addition to the sixth aspect, the fluid ejecting apparatus is configured to eject the second injection amount more than the first injection amount.
[0015]
According to an eighth aspect of the present invention, in addition to the sixth aspect, the fluid injection device causes the injection start timing of the second injection to approach the main fuel injection end timing or overlaps the main fuel injection end timing. It is configured to be sprayed.
[0016]
According to this invention, the fluid injection device supplies a pressurized injection fluid, which is different from the main fuel injected from the fuel injection valve, into the combustion chamber, from the injection valve to the combustion chamber, before the combustion top dead center of the engine. And the injection timing of the main fuel, preferably the first injection so as to overlap the initial injection of the main fuel, and close to the end timing of the main fuel injection as in claim 3 after the top dead center of combustion. Alternatively, the second injection is performed so as to overlap the final injection of the main fuel.
[0017]
The ratio (injection amount ratio) between the injection amount of the first injection and the injection amount of the second injection is set in advance by the fluid injection device according to engine operating conditions such as engine load (engine output) and engine speed. Specifically, as in the second and seventh aspects, the injection amount of the second injection is increased more than the injection amount of the first injection.
[0018]
Therefore, according to such an invention, the first injection of the injection fluid before the combustion top dead center suppresses the increase in the combustion temperature and reduces the amount of NOx generated, while the injection of the pressurized injection fluid at the initial stage of the main fuel injection causes the combustion chamber to The combustion of the injected main fuel is accelerated by accelerating the spray of the injected main fuel by the injection fluid by the second injection of the injection fluid after the top dead center of combustion while promoting the diffusion combustion of the injected main fuel at This increases the maximum in-cylinder pressure, thereby increasing the engine output and increasing the thermal efficiency.
[0019]
In particular, according to the second and seventh aspects, the injection speed of the injected main fuel by the injection fluid is increased by causing the injection amount of the second injection to be greater than the injection amount of the first injection. In addition, an increase in the maximum in-cylinder pressure associated therewith, and a further increase in thermal efficiency accompanying an increase in engine output become significant.
According to the third and eighth aspects of the present invention, the second injection is performed so as to be close to the main fuel injection end time or overlap the main fuel injection end time. By accelerating the main fuel spray, whose diffusion energy is decreasing, with the injection fluid, the diffusion energy is restored and combustion is promoted, so that the engine output and the thermal efficiency increase due to the increase in the in-cylinder maximum pressure are remarkable. It becomes.
[0020]
In short, according to the invention, since the injection amount ratio between the first injection and the second injection of the injection fluid can be freely changed by the fluid injection device, the first injection fluid before the combustion top dead center is obtained. Reduce the amount of NOx generated while maintaining combustion performance by multiple injections, and increase the engine output and increase the thermal efficiency due to the increase in the in-cylinder maximum pressure by the second injection of the injection fluid after combustion top dead center The injection control of the injection fluid can be performed so that the injection amount ratio can be realized in a balanced manner.
[0021]
As the jet fluid, high-temperature water or water vapor as in claim 4 or supercritical water as in claim 5 is suitable, but in particular, if supercritical water as in claim 5 is used, Increased diffusion coefficient due to critical water facilitates the formation of a homogeneous phase of water and fuel, reduces the number of local high-temperature combustion parts, and further suppresses condensation and cooling in the supercritical water, making the temperature distribution uniform in the combustion chamber Is promoted, and the NOx generation suppressing effect is further increased.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, unless otherwise specified, the dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention.
[0023]
FIG. 1 is an injection timing diagram of a four-cycle diesel engine equipped with a two-fluid injection device according to an embodiment of the present invention. FIG. 2 is a system diagram of a two-fluid injection system in the 4-cycle diesel engine, and FIG. 3 is a schematic sectional view around a combustion chamber in the 4-cycle diesel engine. FIG. 4 is a relationship diagram between the injection amount ratio around the top dead center and the thermal efficiency in the embodiment.
[0024]
In FIG. 2 showing the entire system, 1 is a diesel engine (hereinafter abbreviated as an engine), 7 is an air supply manifold of the engine 1, 8 is an exhaust manifold, and 3 is a generator that is directly connected to the engine 1. A turbocharger 4 drives a turbine 4a with exhaust gas introduced from an exhaust manifold 8 of the engine 1 through an exhaust pipe 10 and compresses air by a compressor 4b that is directly connected to the turbine 4a. The supply air is supplied to the supply manifold 7 of the engine 1 through the supply pipe 9. A fuel injection pump 2 pressurizes the main fuel to a high pressure and feeds it to the fuel injection valve 16 (see FIG. 3) of the engine 1.
[0025]
An exhaust heat boiler 5 drives the turbine 4a of the supercharger 4 and exchanges heat between the exhaust gas introduced through the exhaust pipe 10 and the water fed by the feed water pump 6 through the feed water pipe 24. The water is heated to generate high-temperature water or water vapor (or supercritical water as described later). Since the exhaust heat boiler 5 uses a known exhaust heat boiler, its structural description is omitted.
A high-temperature water injection pump 26 pressurizes the high-temperature water generated in the exhaust heat boiler 5 and supplies it as high-pressure high-temperature water to the water injection valve 22 (see FIG. 3) on the engine 1 side through the high-temperature water injection pipe 25. To do.
[0026]
28 is a load detector for detecting the load (output) of the engine 1 for driving the generator 3, and 29 is a rotation speed detector for detecting the engine speed and the crank angle of the engine. The rotation speed detector 29 is provided with a crank angle detector for detecting the crank angle of the engine as required.
Reference numeral 27 denotes a high-temperature water injection control device, which is a detection value of the engine load (output) input from the load detector 28 and a detection value of the engine speed input from the rotation speed detector 29 (if necessary, the crank angle Based on the detected value), a control operation signal for the injection timing of the water injection valve 22 (see FIG. 3) is output to the high-temperature water injection pump 25.
[0027]
In FIG. 3 which shows the outline around the combustion chamber of the engine 1, the engine 1 includes a cylinder liner 19, a cylinder head 12, and a piston 14 which is reciprocated within the cylinder liner 19 with a piston ring 13 interposed therebetween. The connecting rod 15 and the like transmit the reciprocating power of the piston 14 to the generator 3 via a crankshaft (not shown).
In the engine 1, 20 is an air supply port, 21 is an exhaust port, and 11 is a combustion chamber defined by the cylinder head 12 and the piston 14.
[0028]
A fuel injection valve 16 is provided at the center facing the combustion chamber 11, an air supply valve 17 that opens and closes the air supply port and supplies air into the combustion chamber 11 on both the left and right sides, and an exhaust port 21 is opened and closed. The exhaust valve 18 for discharging the exhaust gas from the combustion chamber 11 is completed, and the basic operations of the engine 1, suction, compression, combustion, and exhaust, are completed in four cycles, that is, two rotations of the crankshaft.
Reference numeral 22 denotes a water injection valve which is an object of the present invention, and one or a plurality (two in this example) are provided above the combustion chamber 11 outside the air supply valve 17 and the exhaust valve 18.
[0029]
When the exhaust valve 18 is opened before the bottom dead center of the piston 14 after the combustion in the combustion chamber 11 is performed during the operation of the four-cycle diesel engine equipped with the two-fluid injection system having such a configuration, the exhaust gas The (combustion gas) drives the turbine 4 a of the supercharger 4 from the exhaust port 21 through the exhaust pipe 10, and is guided to the exhaust heat boiler 5 through the exhaust pipe 10.
In the exhaust heat boiler 5, high-temperature water (or supercritical water described later) containing water vapor is heated by exchanging heat between the exhaust gas and water fed through the feed pipe 24 by the feed pump 6. ) Is generated. The high-temperature water is pressurized to a predetermined pressure by a high-temperature water injection pump 26, supplied to the water injection valve 22 of the engine 1, and injected from the water injection valve 22 into the combustion chamber 11 at an injection timing described later. The
[0030]
On the other hand, the air pressurized by the compressor 4 b that is directly connected to the turbine 4 a of the supercharger 4 is guided to the air supply port 20 through the air supply pipe 9, and the combustion chamber 11 is opened by opening the air supply valve 17. To be introduced.
In the intake stroke, when the air supply valve 17 is opened, the piston 14 descends to the bottom dead center, and when the piston 14 rises from the bottom dead center by a certain angle (usually about + 20 ° to 80 °), the air supply is performed. The valve 17 closes and the process proceeds to the compression stroke.
In the compression stroke, the piston 14 ascends, and the compression action of the air in the combustion chamber 11 is started, so that the temperature becomes higher than the self ignition temperature of the main fuel. When the main fuel is injected into the air in the combustion chamber 11 by the fuel injection valve 16 near the end of the compression stroke (around -10 ° to -20 ° from the top dead center), the main fuel is burned by self-ignition and temperature Then, the pressure suddenly rises, and the piston 14 is pushed down to the bottom dead center through the top dead center to perform the expansion work.
[0031]
In the present invention, an injection method or injection means of injection fluid high-temperature water (including water vapor, the same applies hereinafter) (injection fluid) injected from the water injection valve 22 into the combustion chamber 11 is configured as follows. .
That is, in the injection timing diagram of the 4-cycle diesel engine shown in FIG. 1, the high-temperature water from the water injection valve 22 is injected first in the period of θ _{w1 to} θ _w2 before the combustion top dead center of the engine. And the second injection in the period of θ _w3 to θ _w4 after the combustion top dead center.
[0032]
In the first injection before the combustion top dead center, the injection periods θ _{w1 to} θ _w2 are injected during the main fuel injection periods θ _f1 to _θf2 injected into the combustion chamber 11 from the fuel injection valve 16. Injection is performed at an injection timing that overlaps in the initial stage.
In the second injection after the combustion top dead center, the injection period θ _{w3 to} θ _w4 is close to the main fuel injection end time θ _f2 or overlaps the main fuel injection end time. Inject with timing.
[0033]
Also, the ratio (injection amount ratio) of the first injection θ _{w1 to} θ _w2 and the second injection θ _{w3 to} θ _{w4 to} the injection amount is controlled by the high temperature water injection control device 27.
That is, the control of the injection timing and injection period of the high temperature water by the high temperature water injection control device 27 is performed by detecting the engine load (output) input from the load detector 28 to the high temperature water injection control device 27 and detecting the rotational speed. On the basis of the detected value of the engine speed inputted from the vessel 29 (the detected value of the crank angle as required), the first injection θ of the water injection valve 22 as shown in FIG. outputs _w1 through? _w2 and control operation signal of the injection timing of the second stage fuel injection theta _w3 through? _w4 performed by driving operating the high-hot water injection pump 25.
[0034]
In the hot water injection control device 27, freely contain altered the ratio (injection amount ratio) between the injection amount of the injection amount and the 2nd injection theta _w3 through? _W4 of the first-time injection theta _w1 through? _W2, in this embodiment, the second time injection theta _w3 through? the injection amount of _w4 as allowed to injection more than the injection amount of the first-time injection theta _w1 through? _w2, the hot water injection pump 25 and the water injection valve 22 To control.
If comprised in this way, it will become possible to set correctly the injection timing and injection quantity of the said high temperature water according to an engine operating state, the increase effect of an engine output, the suppression effect of NOx generation, and exhaust gas from A higher increase effect of the heat recovery efficiency can be obtained.
The injection timing and injection amount control of the high-temperature water injection pump 25 and the water injection valve 22 are performed by timing gears that are linked to the rotation of the crankshaft (not shown) together with the opening and closing timings of the air supply valve 17 and the exhaust valve 18. May be.
[0035]
Therefore, according to this embodiment, the first injection θ _{w1 to} θ _w2 of the high temperature water (injection fluid) before the combustion top dead center from the water injection valve 22 suppresses the increase in the combustion temperature and reduces the NOx generation amount. However, by injecting pressurized high-temperature water at the initial stage of injection of the main fuel from the fuel injection valve 16, diffusion combustion of the injected main fuel in the combustion chamber 11 is promoted to maintain combustion performance.
Then, the second injection θ _{w3 to} θ _w4 of the pressurized hot water after the combustion top dead center accelerates the spray of the injected main fuel by the pressurized hot water, thereby promoting the combustion. Maximum pressure increases, which increases engine power and increases thermal efficiency.
[0036]
In particular, by a number allowed to injection than the injection amount of the second stage fuel injection theta _w3 through? _W4 injection quantity of the first-time injection theta _w1 through? _W2, hot water by injecting spent main fuel spray enhanced action and its As a result, the increase in the in-cylinder maximum pressure and the increase in the thermal efficiency accompanying the increase in engine output become remarkable.
In addition, the second fuel injection is performed by bringing the second fuel injection θ _{w3 to} θ _w4 close to the main fuel injection end timing θ _f2 or overlapping the main fuel injection end time to thereby overlap the main fuel injection. By accelerating the main fuel spray, whose diffusion energy is decreasing near the end of the cycle, with high-temperature water, the diffusion energy is restored and combustion is promoted to increase engine output and increase thermal efficiency as the maximum in-cylinder pressure increases. The effect becomes remarkable.
[0037]
FIG. 4 is a relationship diagram based on a simulation calculation of the injection amount ratio before and after the top dead center, the in-cylinder maximum temperature, and the thermal efficiency in this embodiment.
In the figure, e, c, and d are conventional technologies, e is no hot water injection, c is hot water injection only before top dead center, and d is hot water injection only after top dead center Indicates.
A and B are the present invention, A is 1 and 25 before top dead center, 1 and 25 after top dead center injection, B is 2 and 5 before top dead center, 2 and 5 after top dead center This is a case of two-time injection.
As is apparent from FIG. 4, in the present invention (A, B), the increase in the in-cylinder maximum temperature is suppressed by the injection of high temperature water before and after top dead center, and the amount of NOx generated is reduced. It becomes possible to maintain high thermal efficiency.
[0038]
Further, supercritical water at 374 ° C. or higher and 22 MPa or higher (or including subcritical water at 250 ° C. to 300 ° C. or higher and 10 MPa or higher) can be used instead of the high temperature water.
In the case of diesel or gas turbine, the supercritical water has an exhaust gas temperature of 550 ° C. or higher, and thus heats the feed water supplied from the feed water pump 6 by the exhaust gas from the engine 1 in the exhaust heat boiler 5. Can be easily manufactured.
[0039]
Supercritical water and subcritical water of 10 MPa or more at 250 ° C. to 300 ° C. or higher have a dielectric constant as low as that of an organic solvent, improving mutual solubility with hydrocarbon fuel, and increasing diffusion coefficient. This facilitates the formation of a uniform phase of water and fuel and reduces the number of local high-temperature combustion parts. Therefore, the generation of NOx during combustion can be suppressed.
Further, as described above, the supercritical water and subcritical water have a larger diffusion coefficient and lower viscosity than liquid water, and are easily diffused during combustion, leading to improvement in combustion efficiency.
Further, the physical properties of the supercritical water and subcritical water change greatly depending on the temperature and pressure near the supercritical point, and therefore these physical properties can be controlled by controlling the temperature and pressure. As a result, it is possible to cope with a wide variety of hydrocarbon fuels and to inject supercritical water according to the form of fuel injection depending on the load and the number of revolutions.
[0040]
In addition, as described above, supercritical water has a large diffusion coefficient, so that mixing with fuel is performed well, and it is not mixed with fuel particles independently like water or water vapor. Since it has characteristics like an organic solvent, it can dissolve in fuel and form a more uniform combustion field.
Since the ratio of fuel to air is around 1:30 in a diesel engine, supercritical water is further added to the fuel and air at a fuel mass ratio of about 2 to 4 (fuel: air: critical water = 1: 30: 2 4) A uniform combustion field as described above can be obtained by injection.
[0041]
【The invention's effect】
As described above, according to the present invention, the first injection of the injection fluid before the combustion top dead center suppresses the increase in the combustion temperature and reduces the NOx generation amount, while reducing the NOx generation amount. The injection promotes the diffusion combustion of the injected main fuel in the combustion chamber to maintain the combustion performance, and the injection of the injected main fuel is accelerated by the injection fluid by the second injection of the injected fluid after the combustion top dead center. By causing the combustion to occur, combustion is promoted and the in-cylinder maximum pressure increases, thereby increasing the engine output and increasing the thermal efficiency.
[0042]
In particular, according to the second and seventh aspects, the injection speed of the injected main fuel by the injection fluid is increased by causing the injection amount of the second injection to be greater than the injection amount of the first injection. As a result, the increase in the in-cylinder maximum pressure, the increase in engine output and the increase in thermal efficiency due to this increase become significant.
[0043]
According to the third and eighth aspects of the present invention, the second injection is performed so as to be close to the main fuel injection end time or overlap the main fuel injection end time. By accelerating the main fuel spray, whose diffusion energy is decreasing, with the injection fluid, the diffusion energy is restored and combustion is promoted, and the increase in engine output and the increase in thermal efficiency due to the increase in the in-cylinder maximum pressure are remarkable. It becomes.
[0044]
In short, according to the invention, since the injection amount ratio between the first injection and the second injection of the injection fluid can be freely changed by the fluid injection device, the first injection fluid before the combustion top dead center can be changed. Reducing the amount of NOx generated while maintaining combustion performance by a single injection, and increasing the engine output and the thermal efficiency due to the increase in the in-cylinder maximum pressure by the second injection of the injection fluid after the combustion top dead center Therefore, it is possible to perform the injection control of the injection fluid so that the injection amount ratio can be achieved in a balanced manner.
[0045]
Further, if supercritical water as in claim 5 is used as the injection fluid, a uniform phase of water and fuel can be easily formed by increasing the diffusion coefficient due to the supercritical water, and the number of local high-temperature combustion parts is reduced. In supercritical water, condensation cooling is suppressed, so that uniform temperature distribution in the combustion chamber is promoted, and the NOx generation suppressing effect is further increased.
[Brief description of the drawings]
FIG. 1 is an injection timing diagram of a four-cycle diesel engine equipped with a two-fluid injection device according to an embodiment of the present invention.
FIG. 2 is a system diagram of a two-fluid injection system in the 4-cycle diesel engine.
FIG. 3 is a schematic sectional view around a combustion chamber in the four-cycle diesel engine.
FIG. 4 is a relationship diagram between an injection amount ratio before and after top dead center and thermal efficiency in the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Fuel injection pump 3 Generator 4 Supercharger 5 Exhaust heat boiler 6 Water supply pump 9 Supply pipe 10 Exhaust pipe 11 Combustion chamber 12 Cylinder head 14 Piston 16 Fuel injection valve 17 Supply valve 18 Exhaust valve 22 Water injection valve 26 High-temperature water injection pump 27 High-temperature water injection control device 28 Load detector 29 Rotation speed detector

Claims (8)

In a method for operating a four-cycle two-fluid injection internal combustion engine in which main fuel and another injection fluid are injected into a combustion chamber and combusted, the injection fluid is divided into two before and after combustion top dead center, and the first injection And the second injection, the injection amount ratio is variable and the injection is performed, and the first injection timing is set to overlap the injection timing of the main fuel. . 2. The method of operating a two-fluid injection internal combustion engine according to claim 1, wherein an injection amount of the second injection is set larger than an injection amount of the first injection. 2. The two-fluid injection internal combustion engine according to claim 1, wherein an injection start timing of the second injection is set to be close to an injection end timing of the main fuel or overlap with an end of injection of the main fuel. Driving method. 2. The method of operating a two-fluid injection internal combustion engine according to claim 1, wherein high-temperature water or water vapor is used as the injection fluid. 2. A method of operating a two-fluid injection internal combustion engine according to claim 1, wherein supercritical water is used as the injection fluid. In a four-cycle two-fluid injection internal combustion engine in which main fuel and another injection fluid are injected into a combustion chamber and combusted, an injection valve that injects the injection fluid into the combustion chamber, and the injection fluid is combusted from the injection valve The first injection and the second injection before and after the top dead center are divided into two, and the first injection timing is overlapped with the main fuel injection timing and the ratio of the two injections is changed. A two-fluid injection device for an internal combustion engine, comprising: a fluid injection device that enables injection. The two-fluid injection device for an internal combustion engine according to claim 6, wherein the fluid injection device is configured to inject an injection amount of the second injection more than an injection amount of the first injection. The fluid injection device is configured such that an injection start timing of the second injection is close to an injection end timing of the main fuel or is overlapped with an injection end timing of the main fuel. 7. A two-fluid injection device for an internal combustion engine according to claim 6.

Images