JP2002155825A - Fuel/water-injection internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel/water-injection internal combustion engine that can precisely control a water injection quantity in a relatively simple control method and reduces the device cost of water injection quantity control operation equipment. SOLUTION: The fuel/water-injection internal combustion engine is designed to inject high-pressure fuel from a fuel injection pump and water supplied from a water supply pump into a combustion chamber from one fuel injection valve. A water injection piston device is provided to force-feed the water to the fuel injection valve by a pressure difference between the pressure in a water chamber for storing the water and the pressure in a working fluid camber separated from the water chamber by a water injection piston. A working fluid pump is provided to pressurize working fluid and feed it to the working fluid chamber of the water injection piston device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for injecting high-pressure fuel supplied from a fuel injection pump via a fuel passage and water supplied from a water supply pump from one fuel injection valve into a combustion chamber. The invention relates to a configured fuel / water injection internal combustion engine.

[0002]

2. Description of the Related Art In a diesel engine, a fuel / water injection diesel engine in which fuel and water are injected from a fuel injection valve into a combustion chamber has been proposed as an effective technique for reducing nitrogen oxides (NOx). . One such technique is the invention of Japanese Patent No. 2772114 filed by the present applicant. FIG. 10 shows the structure of the invention, in which 001 is a fuel injection pump, 3 is a fuel injection valve, 01
Is a fuel tank, 02 is a fuel supply pump, 019 is a water tank, 018 is a water supply pump, 016 is a control valve that controls the supply of water to the fuel injection valve, and 020 is a control device that controls the control valve 016 to open and close. is there.

In this fuel / water injection diesel engine, water pumped from a water tank 019 by a water supply pump 018 is sent to the control valve 016 through a water supply pipe 017. During the fuel discharge suspension period of the fuel injection pump 001, the control valve 0 is controlled via the control device 020.
The valve 16 is opened, and a predetermined amount of water is supplied to the water supply path 021 of the fuel injection valve 3 via the supply pipe 015. At this time, the valve opening pressure P of the check valve 07 of the fuel injection pump 001
r, opening pressure Pp of the fuel valve in the check valve 4 of the water supply path 021, when the opening pressure _{P 0} of the needle valve 011 of the fuel injection valve 3 is set _P 0> _Pr, and P 0> Pp The water supply path 0 of the fuel injection valve 3
The water supplied to the fuel passage 21 passes through the water passage 030 and the fuel / water junction 031 via the fuel valve check valve 4.
It flows into 22.

[0004] The fuel located on the fuel injection pump 001 side of the converging portion 031 in the fuel passage 022 is pushed back toward the fuel injection pump 001 through the high-pressure fuel pipe 08. As a result, the fuel injection valve 3 is filled with the oil reservoir 012 and the fuel corresponding to the volume from the oil reservoir 012 to the junction 031, and the fuel passage 022 on the upstream side of the junction 031.
Is filled with a predetermined amount of water, and the upstream side thereof is again in a layered state filled with fuel.

Next, the discharge of the fuel injection pump 001 is started, the fuel in the fuel injection valve 3 is compressed, and the pressure rises and becomes equal to or higher than the valve opening pressure P ₀ of the fuel injection valve 3.
The needle valve 011 is opened and injection is started. In the injection, among the fuel and water in the stratified state as described above, the fuel is first injected, and after the ignition delay period, the combustion is started. Subsequently, water is injected at the preceding fuel spray flame during combustion. The water injected at this time also becomes a spray and takes in the air in the combustion chamber into the inside thereof, so that air is supplied to the fuel previously injected, and combustion is activated.
Finally, the remaining fuel is injected into the preceding water spray and burns. Due to the thermal effect of the fuel and water injection, the temperature rise of the flame is suppressed, and the generation of NOx is suppressed.

[0006]

In the invention of Japanese Patent No. 2772114 shown in FIG. 10, after fuel and water are filled into the fuel injection valve 3 in layers, the fuel is injected into the combustion chamber by high-pressure fuel and injected. Due to the thermal effect of the fuel and water injection, the temperature rise of the flame is suppressed, and the generation of NOx is suppressed. However, in such a conventional technique, the amount of water injected into the fuel injection valve 3 is controlled by the control device 02.
Since the control is performed by changing the stroke and the valve opening timing of the control valve 016 according to 0, it is necessary to maintain the control accuracy of the control valve 016 high in order to obtain the required water injection amount and the water injection timing. With difficulty. Further, in the conventional technique, as described above, the control valve 016
Is controlled with high control accuracy, the control device 020 performs high-precision timing control of the control valve 016, the operating hydraulic pressure generating device for applying an operating force to the control valve 016, and the electric drive. Since control operation devices such as devices are required, device costs rise. And the like.

The present invention has been made in view of the problems of the prior art,
An object of the present invention is to provide a fuel / water injection internal combustion engine that can perform high-precision water injection control with a relatively simple control method and that reduces the equipment cost of a water injection amount control operation device.

[0008]

According to the present invention, there is provided a fuel / water injection internal combustion engine for injecting fuel and water into a combustion chamber, the fuel injection pump comprising: A fuel supply valve having a fuel supply passage communicating with the fuel passage and a check valve and having a water supply passage merging with the fuel passage, and supplying a predetermined amount of water while the fuel injection pump is stopped. A water supply means for supplying water from the junction to the fuel passage through the passage, and the sum of the volume of the oil reservoir and the volume from the junction to the oil reservoir of the fuel injection valve is 5% of the total fuel injection amount. In the fuel / water injection internal combustion engine having a water supply pump of not less than 75% or less, the pressure in the water chamber in which the water passing through the water passage from the water supply pump is stored and the pressure in the hydraulic oil chamber formed with the water injection piston separated from the water chamber. The water is injected by the fuel A water injection piston device for pressure-feeding to a valve is provided in the water passage, and a hydraulic oil pump for pressurizing hydraulic oil introduced from a hydraulic oil inlet passage and feeding the hydraulic oil to a hydraulic oil chamber of the water injection piston device via a hydraulic oil passage. A fuel / water injection internal combustion engine characterized by being provided is proposed.

According to a second aspect of the present invention, in the first aspect, the water injection piston is constituted by a free piston which is reciprocally slidably fitted in a cylinder and is moved by the pressure difference, and wherein the water chamber outlet is provided. The water passage is provided with a water injection check valve that allows only the flow toward the fuel injection valve, and the water passage at the inlet of the water chamber has a water injection check that allows only the flow toward the water chamber. A stop valve is provided.

According to a third aspect of the present invention, in the first aspect, the hydraulic oil pump is configured to inject the hydraulic oil in the plunger chamber by the reciprocating motion of a plunger slidably fitted in a plunger barrel. And a jerk-type pump configured to adjust the effective oil delivery flow rate by changing the effective stroke of the plunger.

[0011] The invention described in claims 4 and 5 is the third invention.
In the invention of claim 4, the hydraulic oil pump composed of the jerk type pump opens a valve by the pressure of the plunger chamber and operates in the plunger chamber. A hydraulic oil discharge valve for delivering oil to the water injection piston device, and a plunger chamber and the hydraulic oil passage are provided in a return passage that bypasses the hydraulic oil discharge valve, and only flow from the hydraulic oil passage toward the plunger is provided. And a hydraulic oil check valve that enables the check.

According to a fifth aspect of the present invention, the hydraulic oil pump including the jerk type pump is provided with a throttle mechanism for reducing the hydraulic oil passage area between the plunger chamber and the hydraulic oil passage.

According to a sixth aspect of the present invention, in the first aspect, the hydraulic oil chamber of the water injection piston device is connected to a hydraulic oil tank for supplying hydraulic oil to a hydraulic oil inlet pipe to the hydraulic oil pump. Hydraulic oil return passage, engine speed,
An electromagnetic valve that opens and closes the hydraulic oil return passage according to engine operating conditions such as an engine load is provided, and a hydraulic oil inlet passage, a hydraulic oil pump, a hydraulic oil passage, a water injection piston device, a solenoid valve, and a hydraulic oil are provided from the hydraulic oil tank. A hydraulic oil circulation path is formed through the return passage in this order to the hydraulic oil tank.

According to this invention, the hydraulic oil supply timing and the hydraulic oil flow rate are adjusted by the hydraulic oil pump such as a commonly used jerk type fuel injection pump capable of adjusting the hydraulic oil supply timing and the hydraulic oil flow rate. Then, by supplying or shutting off the hydraulic oil to the water injection piston device, the water injection piston device is operated to supply and shut off water to the fuel injection valve by the water injection piston device. The water injection amount and the water injection timing can be controlled with high accuracy by relatively simple control means that only adjusts the hydraulic oil supply timing and the hydraulic oil flow rate of the hydraulic oil pump having the same structure as that of the type fuel injection pump.

Further, as described above, a hydraulic oil pump capable of adjusting hydraulic oil supply timing and hydraulic oil flow rate similar to a jerk type fuel injection pump, and a simple piston in which a water injection piston having a free piston structure is fitted in a cylinder. Since a water supply system to the fuel injection valve is configured by combining with a water injection piston device having a structure, an electronically controlled control valve as in the prior art, a control device for performing timing control of the control valve, and operation of the control valve Special control and operation equipment such as an operating oil pressure generating device and an electric drive device for applying a force are not required, and the fuel / water injection system can be configured with an extremely simple and low-cost device.

According to the fifth aspect of the present invention, the throttling mechanism can mitigate sudden movement of the water injection piston device accompanied by vibration and the like, thereby supplying hydraulic oil to the water injection piston device. Is performed without pulsation or the like, and the water supply operation by the water injection piston device is stabilized. Further, since it is sufficient to provide a diaphragm mechanism having a simple structure, the structure is simplified and the cost is reduced.

According to a sixth aspect of the present invention, the hydraulic oil passes from the hydraulic oil tank through a hydraulic oil inlet passage, a hydraulic oil pump, a hydraulic oil passage, a water injection piston device, a solenoid valve, and a hydraulic oil return passage in this order. A hydraulic oil circulation path to the tank is formed, and a hydraulic oil return passage of the circulation path is opened and closed by a solenoid valve at a timing adapted to the engine operating conditions. Cooling in the oil tank suppresses the temperature rise of the hydraulic oil, and the residual pressure of the hydraulic oil in the water injection piston device is completely removed, so that the water supply in the next step is smoothly performed without resistance . This stabilizes the water supply action by the hydraulic oil pump and the water injection piston device.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not merely intended to limit the scope of the present invention, but are merely illustrative examples unless otherwise specified. Absent.

FIG. 1 is a configuration diagram of a fuel / water injection system of a diesel engine according to a first embodiment of the present invention, FIG. 2 is a configuration diagram of a fuel / water injection system of a diesel engine according to a second embodiment, FIG. Is the fuel of the diesel engine according to the third embodiment.
FIG. 4 is a cross-sectional view of a water injection piston device, FIG. 5 is a cross-sectional view showing the structure of a fuel injection pump and a working oil pump in the first embodiment, and FIG. 6 is a fuel diagram in the second embodiment. FIG. 7 is a sectional view showing the structure of the injection pump and the working oil pump, and FIG. 7 is a sectional view showing the structure of the fuel injection pump and the working oil pump in the third embodiment. FIG.
FIG. 3 is a sectional view of a fuel injection valve in the first to third embodiments. FIG. 9 is a diagram for explaining the operation of the first to third embodiments.

In the first embodiment shown in FIG. 1, reference numeral 1 denotes a fuel injection pump, which comprises a known jerk type fuel injection pump as shown in FIG. Reference numeral 3 denotes a fuel injection valve whose details are shown in FIG. Reference numeral 6 denotes a hydraulic oil pump whose details are shown in FIG. 13 is a fuel tank, 31 is a fuel supply pipe connecting the fuel tank 13 and the fuel inlet of the fuel injection pump 1, 12 is provided in the fuel supply pipe 31 and transfers the fuel in the fuel tank 13 to the fuel injection pump 1. It is a fuel supply pump for feeding. A high-pressure fuel pipe 2 connects a high-pressure fuel outlet from the fuel injection pump 1 and a fuel inlet of the fuel injection valve 3.

Reference numeral 5 denotes a water injection piston device, which will be described later in detail. 11 is a water injection tank, 34 is a water injection pipe connecting the water injection tank 11 and the water inlet of the water injection piston device 5, 10.
Is a water injection pump provided in the water injection pipe 34 to supply water in the water injection tank 11 to the water injection piston device 5. Reference numeral 32 denotes a water injection pipe connecting the water outlet of the water injection piston device 5 and the water inlet of the fuel injection valve 3. 15 is a hydraulic oil tank, 33 is a hydraulic oil inlet pipe connecting the hydraulic oil tank 15 to the hydraulic oil inlet of the hydraulic oil pump 6, and 14 is an operating oil tank provided in the hydraulic oil inlet pipe 33. This is a working oil supply pump that supplies oil to the working oil pump 6. Reference numeral 35 denotes a hydraulic oil pipe connecting a hydraulic oil outlet of the hydraulic oil pump 6 and a hydraulic oil inlet of the water injection piston device 5.

In FIG. 5 showing details of the fuel injection pump and the hydraulic oil pump, reference numeral 1 denotes a fuel injection pump which is constructed as follows. Reference numeral 25 denotes a plunger fitted to the inner periphery of the plunger barrel 24 so as to be reciprocally slidable. Reference numeral 17 denotes a fuel discharge valve. Reference numeral 18 denotes a fuel check valve. Pressurized,
The high-pressure fuel pushes the fuel discharge valve 17 open and is discharged to the high-pressure fuel pipe 2. The fuel injection pump 1 comprises a well-known jerk type fuel injection pump as described above, and discharges the high-pressure fuel pipe 2 by changing the effective stroke of the plunger 25 by reciprocating a fuel adjustment rack (not shown). The fuel injection amount is adjusted. Reference numeral 13 denotes a fuel tank, reference numeral 31 denotes a fuel supply pipe, and reference numeral 12 denotes a fuel supply pump. Reference numeral 110 denotes a rack position detector for detecting the position of the fuel adjustment rack, that is, a fuel injection amount. A detection signal of the fuel adjustment rack position (fuel injection amount) from the rack position detector 110 is input to a controller 106 described later. . 11
Reference numeral 1 denotes an engine speed detector for detecting the engine speed. The engine speed detection signal from the engine speed detector 111 is also input to the controller 106.

Reference numeral 6 denotes a hydraulic oil pump which is configured as follows. 101 is a pump case, 102 is a plunger barrel fixed inside the pump case 101, 103 is a plunger fitted to the inner periphery of the plunger barrel 102 so as to be reciprocally slidable, 103a is the plunger barrel 10
A plunger chamber formed facing the upper surface of the plunger 103 in 2, 2 is an oil supply hole provided in the plunger barrel 102. 113 is a tappet fixed to the lower end of the plunger 103, 115 is the tappet 113
The tappet 11 is supported by a plunger spring supported by
3 is pressed against the hydraulic oil cam 114 shown in FIG. Reference numeral 8 denotes a hydraulic oil discharge valve provided on the outlet side of the plunger chamber 103a, and has the same structure as the fuel discharge valve 17 of the fuel injection pump 1. Reference numeral 7 denotes a hydraulic oil check valve which has the same structure as the fuel check valve 18 of the fuel injection pump 1 and connects a discharge valve chamber provided with the fuel discharge valve 17 to the plunger chamber 103a. It is provided in the return passage.

Reference numeral 109 denotes a discharge flow rate adjusting rack meshed with the rotation mechanism 112 of the plunger 103, and reference numeral 108 denotes a pinion meshed with the rack 109. An actuator 107 is operated by a control signal from a controller 106 to be described later, and has an output terminal connected to the pinion 10.
8, the pinion 108 is rotated by the operation force of the actuator 107 to reciprocate the rack 109, and the plunger 103 is rotated via the rotation mechanism 112 of the plunger 103 meshing with the rack 109. Thus, the effective stroke is changed to adjust the flow rate of the working oil to the water injection piston device 5 through the working oil pipe 35. Reference numeral 106 denotes a controller to which a detection signal of an engine rotation speed from the rotation speed detector 111 and a detection signal of a fuel adjustment rack position (fuel injection amount) from the rack position detector 110 are input, and based on these detection signals. A hydraulic oil flow rate corresponding to the operating state of the engine is calculated, and an operation signal corresponding to the hydraulic oil flow rate is output to the actuator 107. Reference numeral 15 denotes a hydraulic oil tank, 33 denotes a hydraulic oil inlet pipe, and 14 denotes a hydraulic oil pump (in all cases, see FIG. 1).

In FIG. 8 showing the details of the fuel injection valve 3, reference numeral 09 denotes a main body, reference numeral 033 denotes a nozzle tip, reference numeral 010 denotes a plurality of injection holes formed at the tip of the nozzle tip 033;
1 is a needle valve fitted reciprocally slidably in the nozzle tip 033, 014 is a needle valve spring for setting the valve opening pressure of the needle valve 011, and 012 is an oil reservoir facing the tip of the needle valve 011. Department. A fuel passage 022 has an inlet end connected to the high-pressure fuel pipe 2 and an outlet end connected to the oil reservoir 012. Reference numeral 021 denotes a water supply passage having an inlet end connected to the water injection pipe 32 from the water injection piston device 5 and an outlet end connected to a water passage 030 formed below the nozzle tip 033. The outlet end of the water passage 030 joins the lower part of the fuel passage 022 to form a joining portion 031.

Reference numeral 4 denotes a non-return valve in the fuel valve provided in the water supply passage 21 so as to allow only the flow from the water injection pipe 32 side to the junction portion 031 and to increase the valve opening pressure Pp. needle valve is made smaller than the opening pressure P ₀ of 011. The basic structure of the fuel injection valve 3 shown above is the same as the fuel injection valve in the invention of Japanese Patent No. 2772114 shown in FIG.

In FIG. 4 showing the details of the water injection piston device, 51 is a cylinder, 52 is a water injection piston fitted reciprocally slidably in the cylinder 51, and 56 is inserted into the outer periphery of the water injection piston 52. It is a sealed ring.
The inside of the cylinder 51 is divided into a water chamber 53 and a hydraulic oil chamber 54 by the water injection piston 52, and the water injection piston 52 is freely moved by a pressure difference between the hydraulic oil chamber 54 and the water chamber 53. It is composed of a piston.

The working oil from the working oil pump 6 is supplied to the working oil chamber 54 by the working oil pipe 35 and the working oil inlet 55.
It has been introduced through. Reference numeral 9 denotes a water inlet check valve which is connected to the water inlet pipe 34 and sets the spherical valve body 9a to a predetermined valve opening pressure so as to allow only the flow from the water inlet pipe 34 to the water chamber 53. It is configured to be pressed by the applied spring 9b. Reference numeral 16 denotes a water injection check valve on the outlet side, which is connected to the water injection pipe 32 and opens the spherical valve body 16a by a predetermined amount so as to allow only the flow from the water chamber 53 to the water injection pipe 32. It is configured to be pressed by a spring 16b set to a pressure.

During operation of the diesel engine having the fuel / water injection system having the above configuration, the water in the water injection tank 11 is pressurized by the water injection pump 10 and the pressure in the water chamber 53 of the water injection piston device 5 is increased. Is the hydraulic oil chamber 54
Side pressure, that is, greater than the valve opening pressure of the hydraulic oil check valve 7 of the hydraulic oil pump 6, the water pumped by the water injection pump 10 from the water injection tank 11 passes through the water injection pipe 34 and passes through the water injection check valve 9. It is pushed open and introduced into the water chamber 53 of the water injection piston device. On the other hand, in the hydraulic oil pump 6, the hydraulic oil cam 114 does not lift and the plunger 103
Is below, the hydraulic oil in the hydraulic oil tank 15 is introduced into the plunger chamber 103a by the hydraulic oil supply pump 14 through the hydraulic oil inlet pipe 33 and the oil supply hole 0111. Then, during the fuel discharge suspension period of the fuel injection pump 1,
When the tappet 113 and the plunger 103 are pushed up by the rotation of the working oil cam 114 of the working oil pump 6, the working oil in the plunger chamber 103 a is pressurized by the plunger 103 and pushes up the working oil discharge valve 8, thereby causing the working oil pipe 3 to move up.
5 and enters the hydraulic oil chamber 54 of the water injection piston device 5.

The high-pressure hydraulic oil entering the hydraulic oil chamber 54 acts on the hydraulic oil chamber side 52b of the water injection piston 52, and the pressure difference between the hydraulic oil pressure and the water pressure acting on the water chamber side 52a. The water injection piston 52 is moved to the left in FIGS. 1 and 4, that is, in a direction to reduce the volume of the water chamber 53, whereby the water introduced into the water chamber 53 is removed by the water injection check valve 16.
And is fed through the water injection pipe 32 into the water supply path 021 of the fuel injection valve 3. At this time, the fuel injection pump 1
Opening pressure Pr of the fuel check valve 18 in the water supply passage 21
The opening pressure Pp of the fuel valve in the check valve 4, when the opening pressure _{P 0} of the needle valve 011 of the fuel injection valve 3, _P 0> _Pr, because it is set to P 0> Pp, the fuel injection Water supply path 0 for valve 3
The water supplied to the fuel passage 21 passes through the water passage 030 and the fuel / water junction 031 via the fuel valve check valve 4.
It flows into 22.

The fuel located on the fuel injection pump 1 side of the merging portion 031 in the fuel passage 022 is supplied to the fuel injection pump 1.
Is pushed back through the high-pressure fuel pipe 2 in the direction of. As a result, the fuel injection valve 3 is filled with the oil reservoir 012 and the fuel corresponding to the volume from the oil reservoir 012 to the junction 031, and the fuel passage 022 on the upstream side of the junction 031 is filled with a predetermined amount. Is filled with water, and further upstream is in a layered state with fuel again. Next, as shown in a "fuel injection" state of FIG. 9, the discharge of the fuel injection pump 1 is started, the fuel in the fuel injection valve 3 is compressed, the pressure is increased, and the fuel injection valve 3 is opened. When pressure P ₀ or more,
The needle valve 011 is opened and injection is started. In the injection, among the fuel and water in the stratified state as described above, the fuel is first injected, and after the ignition delay period, the combustion is started. Subsequently, water is injected at the preceding fuel spray flame during combustion. The water injected at this time also becomes a spray and takes in the air in the combustion chamber into the inside thereof, so that air is supplied to the fuel previously injected, and combustion is activated.
Finally, the remaining fuel is injected into the preceding water spray and burns. Due to the thermal effect of the fuel and water injection, the temperature rise of the flame is suppressed, and the generation of NOx is suppressed.

During the operation, the controller 1
In 06, a detection signal of the engine rotation speed from the rotation speed detector 111 and a detection signal of the fuel adjustment rack position (fuel injection amount) from the rack position detector 110 are input.
Then, the controller 106 calculates a hydraulic oil flow rate corresponding to the operating state of the engine based on these detection signals,
An operation signal corresponding to the hydraulic oil flow rate is output to the actuator 107. The pinion 108 is rotated by the operation force of the actuator 107 to cause the rack 109 to reciprocate, and the effective stroke is reduced by rotating the plunger 103 via the rotation mechanism 112 of the plunger 103 meshing with the rack 109. Then, the flow rate of the working oil to the water injection piston device 5 is adjusted. Thereby, the amount of water supplied to the fuel injection valve 3 by the hydraulic oil is adjusted. Further, by setting the profile of the hydraulic oil cam 114 provided on the hydraulic oil pump 6 to a required shape, the supply timing of the hydraulic oil by the hydraulic oil pump 6 is adjusted. , The timing of supplying water to the fuel injection valve 3 can be adjusted.

According to this embodiment, the operating oil supply timing and the operating oil flow rate are adjusted by the operating oil pump 6 having the same structure as a commonly used jerk type fuel injection pump, and the operating oil is injected into the piston device. The water injection piston device 5 is actuated by supplying or shutting off the water to the fuel injection valve 5 so that the water injection piston device 5 can supply and shut off the water to the fuel injection valve 3. The water injection amount and the water injection timing can be controlled with high accuracy by a relatively simple control means that only adjusts the hydraulic oil supply timing and the hydraulic oil flow rate of the hydraulic oil pump 6 having the same structure as that described above. Further, as described above, the hydraulic oil pump 6 having the same structure as the jerk type fuel injection pump and the water injection piston device 5 having a simple structure in which the water injection piston 52 having the free piston structure is fitted in the cylinder 51 are combined. Since the system for supplying water to the fuel injection valve 3 is configured, a special electronic control device as in the prior art is not required, and the fuel and fuel supply system is extremely simple and low cost.
A water injection system can be configured.

In the second embodiment shown in FIG. 2 and FIG.
The hydraulic oil discharge valve 8 and the hydraulic oil check valve 7 in the embodiment are removed, and a throttle mechanism 40 is provided instead. According to this embodiment, the hydraulic oil pump 6 and the water injection piston device 5
The throttle mechanism 40 is provided in the hydraulic fluid passage between the water injection piston and the water injection piston 52 of the water injection piston device 5, whereby sudden movement of the water injection piston 52 accompanying vibration or the like can be reduced. The supply of hydraulic oil to the piston device 5 is performed without pulsation or the like, and the water supply operation by the water injection piston device 5 is stabilized. Further, as compared with the hydraulic oil discharge valve 8 and the hydraulic oil check valve 7 as in the first embodiment, it is sufficient to provide the throttle mechanism 40 having a simple structure, so that the structure is simplified and the cost is reduced. Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

In the third embodiment shown in FIGS. 3 and 6, reference numeral 36 denotes a hydraulic oil return pipe connecting the hydraulic oil chamber 54 of the water injection piston device 5 and the hydraulic oil tank 15, and
Is a solenoid valve for opening and closing the pipeline of the hydraulic oil return pipe 36,
By providing the hydraulic oil return pipe 36 and the solenoid valve 300, the hydraulic oil tank 15, the hydraulic oil inlet pipe 33, the hydraulic oil supply pump 14, the hydraulic oil inlet pipe 33, the hydraulic oil pump 6, the hydraulic oil pipe 35, and the water injection piston are provided. Device 5, solenoid valve 30
0 and a hydraulic oil return pipe 36 in this order to form a hydraulic oil circulation path to the hydraulic oil tank 15.

Numeral 301 denotes a solenoid valve driving device, which is a rotary shaft 303 such as a crankshaft or a camshaft, as in the first and second embodiments.
The rotation speed detection signal is input from the rotation speed detector 111, and a detection signal of the engine load such as the engine load or output is input from the load detector 304. In the solenoid valve driving device 301, hydraulic oil is supplied from the hydraulic oil pump 6 to the hydraulic oil chamber 54 of the water injection piston device 5, and the water injection piston 52 of the water injection piston device 5 moves leftward in FIG. After sending the water in the chamber 53 to the fuel injection valve 3, the solenoid valve 300 is opened, and the hydraulic oil in the hydraulic oil chamber 54 is returned to the hydraulic oil tank 15 via the hydraulic oil return pipe 36.
In the solenoid valve driving device 301, the solenoid valve 300 is opened and closed at an opening and closing timing adapted to the operating conditions of the engine based on the rotation speed detection signal and the engine load detection signal. With this operation, the residual pressure of the hydraulic oil in the hydraulic oil chamber 54 is completely removed, and the supply of water to the water chamber 53 in the next step is smoothly performed without any resistance.

According to this embodiment, from the hydraulic oil tank 15, the hydraulic oil supply pump 14, the hydraulic oil pump 6, the water injection piston device 5, the solenoid valve 300, and the hydraulic oil return pipe 3
6, a hydraulic oil circulation path to the hydraulic oil tank 15 is formed through the solenoid valve 3 in this order.
Since the hydraulic oil is opened and closed at a timing adapted to the engine operating conditions by 00, the hydraulic oil is returned to the hydraulic oil tank 15 every cycle and is cooled in the hydraulic oil tank 15, so that the temperature rise of the hydraulic oil is suppressed and Then, the residual pressure of the hydraulic oil in the hydraulic oil chamber 54 is completely removed, and the supply of water to the water chamber 53 in the next step is smoothly performed without any resistance. Thereby, the water supply action by the hydraulic oil pump 6 and the water injection piston device 5 is stabilized.

[0038]

As described above, according to the present invention, the hydraulic oil supply timing and the hydraulic oil flow rate are adjusted by the hydraulic oil pump, and the hydraulic oil is supplied to the water injection piston device or cut off, thereby providing the water injection. Since the supply and cutoff of water to the fuel injection valve is performed by the piston device, the hydraulic oil supply timing and the hydraulic oil flow rate of the hydraulic oil pump with the same structure as a commonly used jerk type fuel injection pump are adjusted. The water injection amount and the water injection timing can be controlled with a high degree of accuracy by a relatively simple control means.

Further, as described above, the hydraulic oil pump capable of adjusting the hydraulic oil supply timing and the hydraulic oil flow rate is combined with a water injection piston device having a simple structure in which a free piston water injection piston is fitted in a cylinder. As a result, the water supply system to the fuel injection valve has been configured, so there is no need for special control and operation equipment by electronic control as in the prior art.
With a very simple and low-cost device, a fuel / water injection system can be constructed.

According to the fifth aspect of the present invention, the throttle mechanism can mitigate a sudden movement of the water injection piston device accompanying vibration or the like of the water injection piston device. Is supplied without pulsation, and the water supply operation by the water injection piston device is stabilized. Further, since it is sufficient to provide a diaphragm mechanism having a simple structure, the structure is simplified and the cost is reduced.

Further, according to the sixth aspect of the present invention, the hydraulic oil from the hydraulic oil tank to the hydraulic oil tank through the hydraulic oil pump, the water injection piston device, the solenoid valve, and the hydraulic oil return passage in this order. A circulation path is formed, and the hydraulic oil return passage of the circulation path is opened and closed by a solenoid valve at a timing adapted to the engine operating conditions, so that the hydraulic oil is returned to the hydraulic oil tank every cycle and cooled by the hydraulic oil tank. As a result, the temperature rise of the hydraulic oil is suppressed, and the residual pressure of the hydraulic oil in the water injection piston device is completely removed, so that the supply of water in the next step is smoothly performed without resistance. This stabilizes the water supply action by the hydraulic oil pump and the water injection piston device.

In summary, according to the present invention, there is provided a hydraulic oil pump capable of adjusting hydraulic oil supply timing and hydraulic oil flow rate, and a water injection piston device having a simple structure in which a free piston water injection piston is fitted in a cylinder. The present invention provides a fuel / water injection internal combustion engine that can perform high-precision water injection amount and water injection timing control with relatively simple control means and reduce the equipment cost of a water injection amount control operation device. be able to.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fuel / water injection system for a diesel engine according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a fuel / water injection system of a diesel engine according to a second embodiment.

FIG. 3 is a configuration diagram of a fuel / water injection system of a diesel engine according to a third embodiment.

FIG. 4 is a sectional view of a water injection piston device.

FIG. 5 is a sectional view showing a structure of a fuel injection pump and a hydraulic oil pump in the first embodiment.

FIG. 6 is a sectional view showing the structure of a fuel injection pump and a hydraulic oil pump in the second embodiment.

FIG. 7 is a sectional view showing a structure of a fuel injection pump and a hydraulic oil pump in the third embodiment.

FIG. 8 is a sectional view of a fuel injection valve in the first to third embodiments.

FIG. 9 is an operation explanatory view of the first to third embodiments.

FIG. 10 is a main part configuration diagram showing a conventional technique.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fuel injection pump 2 high-pressure fuel pipe 3 fuel injection valve 4 check valve inside fuel valve 5 water injection piston device 6 hydraulic oil pump 7 hydraulic oil check valve 8 hydraulic oil discharge valve 9 water injection check valve 10 water injection pump 010 injection hole 11 Water injection tank 011 Needle valve 12 Fuel supply pump 012 Oil reservoir 13 Fuel tank 14 Hydraulic oil supply pump 15 Hydraulic oil tank 16 Water injection check valve 17 Fuel discharge valve 18 Fuel check valve 24 Plunger barrel 25 Plunger 32 Water injection pipe 031 Merging part 34 water injection pipe 35 hydraulic oil pipe 36 hydraulic oil return pipe 40 throttle mechanism 51 cylinder 52 water injection piston 53 water chamber 54 hydraulic oil chamber 102 plunger barrel 103 plunger 103a plunger chamber 106 controller 107 actuator 109 rack 110 rack position detector 111 rotation number detector 114 operation Cam 300 solenoid valve 301 solenoid valve driving device 304 load detector

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tatsuo Takaishi 5-717-1, Fukahori-cho, Nagasaki-shi Mitsubishi Heavy Industries, Ltd. Nagasaki Research Laboratory Co., Ltd. (72) Inventor Hiroyuki Ishida 5-717-1, Fukahori-cho, Nagasaki-shi Mitsubishi (72) Inventor Kenichi Iwanaga 5-717-1, Fukabori-cho, Nagasaki City Mitsubishi Heavy Industries, Ltd.Nagasaki Research Laboratory (72) Inventor Akira Numata 3000 Tana, Tana, Sagamihara-shi, Kanagawa Prefecture Mitsubishi Heavy Industries (72) Inventor Takeshi Arai 12 Nishikicho, Naka-ku, Yokohama-shi Mitsubishi Heavy Industries, Ltd.Yokohama Works F-term (reference) 3G066 AA07 AB02 AB08 AC06 AD01 AD04 AD07 BA25 BA51 BA61 CB07U CC06T CC14 CE12 CE22 CE34 DA00

Claims (6)

[Claims] 1. A fuel / water injection internal combustion engine for injecting fuel and water into a combustion chamber, comprising a fuel passage communicating with a fuel injection pump and a check valve, and a water supply merging with the fuel passage. A fuel injection valve having a passage, and a water supply means for supplying a predetermined amount of water from the junction to the fuel passage through the water supply passage while the fuel injection pump is inactive. The sum of the volume of the oil reservoir of the valve and the volume from the junction in the previous period to the oil reservoir is 5% or more of the total fuel injection amount.
In a fuel / water injection internal combustion engine of 5% or less, the pressure in a water chamber in which water that has passed through a water passage from a water supply pump is stored, and the pressure in a hydraulic oil chamber formed with a water injection piston in the water chamber. A water injection piston device for pressure-feeding the water to the fuel injection valve by the pressure difference is provided in the water passage, and hydraulic oil introduced from a hydraulic oil inlet passage is pressurized to supply hydraulic oil to a hydraulic oil chamber of the water injection piston device. A fuel / water-injection internal combustion engine comprising a hydraulic oil pump for feeding through a passage. 2. The water injection piston is constituted by a free piston which is reciprocally slidably fitted in a cylinder and is moved by the pressure difference. The water passage at the outlet of the water chamber is provided with the fuel injection valve. A water injection check valve that allows only the flow toward the water chamber is provided, and a water injection check valve that allows only the flow toward the water chamber is provided in the water passage at the entrance of the water chamber. The fuel / water injection internal combustion engine according to claim 1, wherein 3. The hydraulic oil pump sends hydraulic oil in a plunger chamber to the water injection piston device by reciprocating a plunger fitted reciprocally slidably in a plunger barrel, and controls an effective stroke of the plunger. 2. The fuel / water injection internal combustion engine according to claim 1, comprising a jerk type pump configured to be able to adjust a hydraulic oil delivery flow rate by changing. 4. A hydraulic oil pump comprising the jerk-type pump, wherein the hydraulic oil pump is opened by the pressure of the plunger chamber and discharges hydraulic oil in the plunger chamber to the water injection piston device; A hydraulic oil check valve that is provided in the return passage that bypasses the hydraulic oil passage and the hydraulic oil discharge valve and that allows only the flow from the hydraulic oil passage toward the plunger. Item 3. A fuel / water injection internal combustion engine according to item 3. 5. The hydraulic oil pump comprising the jerk type pump, wherein a throttle mechanism for reducing the area of the hydraulic oil passage is provided between the plunger chamber and the hydraulic oil passage. Fuel / water injection internal combustion engine. 6. A hydraulic oil return passage connecting a hydraulic oil chamber of the water injection piston device and a hydraulic oil tank for supplying hydraulic oil to a hydraulic oil inlet pipe to the hydraulic oil pump, an engine speed, and an engine. An electromagnetic valve for opening and closing the hydraulic oil return passage according to engine operating conditions such as a load is provided, and a hydraulic oil inlet passage, a hydraulic oil pump, a hydraulic oil passage, a water injection piston device, a solenoid valve, and a hydraulic oil return are provided from the hydraulic oil tank. 2. A fuel / water injection internal combustion engine according to claim 1, wherein a circulation path of hydraulic oil reaching the hydraulic oil tank through the passage in this order is formed.