阅读说明：本技术 注水泵 (Water injection pump ) 是由 柿元泰 松田力 青田昭仁 于 2019-09-12 设计创作，主要内容包括：本发明的一方式的注水泵具备：多个水排出通路,该多个水排出通路通过配管与设置于一个气缸的多个燃料喷射阀分别连通；多个水活塞部,该多个水活塞部分别以能够往复移动的方式设置于所述多个水排出通路内；以及液压活塞部。所述液压活塞部利用工作油的压力来使所述多个水活塞部向所述多个水排出通路的排出口侧移动。所述多个水活塞部对所述多个水排出通路内的水加压而向所述多个燃料喷射阀分别排出。(A water injection pump according to an aspect of the present invention includes: a plurality of water discharge passages that communicate with a plurality of fuel injection valves provided in one cylinder through pipes, respectively; a plurality of water piston portions provided in the plurality of water discharge passages so as to be capable of reciprocating, respectively; and a hydraulic piston portion. The hydraulic piston portion moves the plurality of water piston portions to the discharge outlet side of the plurality of water discharge passages by the pressure of the hydraulic oil. The plurality of water piston portions pressurize water in the plurality of water discharge passages and discharge the water to the plurality of fuel injection valves, respectively.)

1. A water injection pump is characterized by comprising:

a plurality of water discharge passages that communicate with a plurality of fuel injection valves provided in one cylinder through pipes, respectively;

a plurality of water piston portions which are provided in the plurality of water discharge passages so as to be capable of reciprocating, respectively, and which pressurize water in the plurality of water discharge passages and discharge the water to the plurality of fuel injection valves, respectively; and

and a hydraulic piston unit that moves the plurality of water piston units to a discharge outlet side of the plurality of water discharge passages by a pressure of hydraulic oil.

2. The water injection pump of claim 1,

a connecting portion for connecting the plurality of hydraulic piston portions and the hydraulic piston portion,

the plurality of water piston portions move integrally with the hydraulic piston portion.

3. Water injection pump according to claim 1 or 2,

the plurality of water discharge passages communicate with the plurality of fuel injection valves at the same position of the fuel passage.

4. Water injection pump according to one of the claims 1 to 3,

the plurality of water piston portions are pistons having the same diameter as each other.

Technical Field

The invention relates to a water injection pump.

Background

In a marine diesel engine mounted on a ship, water technology has been proposed as a method for reducing nitrogen oxides (NOx) in exhaust gas discharged from a combustion chamber in a cylinder. In this water technology, for example, fuel and water are added to the combustion chamber from a fuel injection valve provided in the cylinder, so that the temperature rise of flame when the fuel is combusted in the combustion chamber is suppressed, and as a result, the amount of NOx discharged from the combustion chamber is reduced. In such a water technique, a hydraulically driven water injection pump that utilizes the pressure of hydraulic oil is used to inject water into fuel present in a fuel passage in a fuel injection valve during a period other than an injection period during which fuel is injected into a combustion chamber (hereinafter, referred to as an injection suspension period). As an example of the hydraulically driven water injection pump, patent document 1 discloses a water injection piston device. Hereinafter, the water injection pump is a hydraulically driven water injection pump exemplified in the water injection piston device.

In the diesel engine described in patent document 1, one fuel injection valve is provided in one cylinder, and fuel and water are injected from the one fuel injection valve into a combustion chamber in the cylinder. Subsequently, during the injection suspension period, the fuel to be injected next remains in the fuel passage in the fuel injection valve. The water injection pump is generally configured to communicate with the fuel passage in the fuel injection valve via a pipe or the like. During the injection suspension period, the water injection pump injects water into the fuel in the fuel passage by pressurizing and delivering water at a pressure greater than the pressure of the fuel remaining in the fuel passage (hereinafter referred to as a residual fuel pressure). The fuel and the water in the fuel passage are injected from the fuel injection valve into the combustion chamber in the next injection period after the injection suspension period.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 4550991

Technical problem to be solved by the invention

In recent years, in marine diesel engines, a plurality of (for example, 2 to 3) fuel injection valves are likely to be provided in one cylinder in order to uniformly inject fuel into a combustion chamber. In this case, in order to inject water into each of the plurality of fuel injection valves, the water injection pump is generally configured to communicate with the fuel passages in the plurality of fuel injection valves through a branched pipe (branched pipe) or the like corresponding to the number of fuel injection valves (hereinafter, referred to as a first conventional configuration). Alternatively, a plurality of water injection pumps are prepared, and these water injection pumps are configured to communicate with the fuel passages in the plurality of fuel injection valves through pipes or the like (hereinafter, referred to as a second conventional configuration).

However, there is a possibility that the residual fuel pressure may vary among the plurality of fuel injection valves provided in one cylinder. Therefore, in the first conventional configuration, the injection of water from the water injection pump to the fuel injection valve having the lower residual fuel pressure among the plurality of fuel injection valves is easier than the injection of water to the fuel injection valve having the higher residual fuel pressure, and therefore, the amount of water injected from the water injection pump to each of the plurality of fuel injection valves varies. In the second conventional configuration, not only the number of parts is increased and the configuration is complicated, but also the variation in the amount of injected water may be increased due to manufacturing variation between the water injection pumps. Further, since it is difficult to predict the tendency of the variation in residual fuel pressure, it is difficult to eliminate the variation in the amount of water injection between the plurality of fuel injection valves by controlling the driving of the plurality of water injection pumps.

Further, the variation (unevenness) in the amount of injected water among the plurality of fuel injection valves is a cause of variation in the amount of fuel injected into the combustion chamber among the plurality of fuel injection valves, and causes variation in the length of flame and the amount of heat generated during combustion of the fuel in the combustion chamber. This not only deforms the components related to the combustion chamber such as the cylinder and the piston, causing variation in the amount of wear of the components, but also causes a decrease in the combustion efficiency (i.e., deterioration in the fuel efficiency) of the marine diesel engine.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a water injection pump capable of injecting water into a plurality of fuel injection valves provided in one cylinder and suppressing variation in the amount of injected water among the plurality of fuel injection valves.

Means for solving the problems

In order to solve the above-described problems and achieve the object, a water injection pump according to the present invention includes: a plurality of water discharge passages that communicate with a plurality of fuel injection valves provided in one cylinder through pipes, respectively; a plurality of water piston portions which are provided in the plurality of water discharge passages so as to be capable of reciprocating, respectively, and which pressurize water in the plurality of water discharge passages and discharge the water to the plurality of fuel injection valves, respectively; and a hydraulic piston unit that moves the plurality of water piston units to a discharge port side of the plurality of water discharge passages by a pressure of hydraulic oil.

In the above-described invention, the water injection pump according to the present invention includes a coupling portion that couples the plurality of water piston portions and the hydraulic piston portion, and the plurality of water piston portions and the hydraulic piston portion move integrally.

In the above-described invention, the plurality of water discharge passages of the water injection pump according to the present invention communicate with the plurality of fuel injection valves at the same position of the fuel passage. In the above-described invention, the plurality of water piston portions of the water injection pump according to the present invention are pistons having the same diameter.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the following effects are achieved: the water injection can be performed to a plurality of fuel injection valves provided in one cylinder, and variation in the amount of water injected among the plurality of fuel injection valves can be suppressed.

Drawings

Fig. 1 is a schematic diagram showing a configuration example of a fuel injection system of a marine diesel engine according to an embodiment of the present invention.

Fig. 2 is a schematic side sectional view showing a configuration example of a water injection pump according to an embodiment of the present invention.

Fig. 3 is a schematic sectional view taken along line a-a of the water injection pump shown in fig. 2.

Fig. 4 is a diagram for explaining the operation of the water injection pump according to the embodiment of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the water injection pump according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the present embodiment. Note that the drawings are schematic, and the dimensional relationship, the ratio, and the like of the elements may be different from those in reality. The drawings may include portions having different dimensional relationships and ratios from each other. In the drawings, the same components are denoted by the same reference numerals.

(Structure of Fuel injection System)

First, the configuration of a fuel injection system of a marine diesel engine to which a water injection pump according to an embodiment of the present invention is applied will be described, and fig. 1 is a schematic diagram showing a configuration example of the fuel injection system of the marine diesel engine according to the embodiment of the present invention. As shown in fig. 1, the fuel injection system 100 includes a plurality of (three in the present embodiment) fuel injection valves 20A, 20B, and 20C, a fuel pressure feed system 30, a downstream side water injection system 40, and an upstream side water injection system 50. The fuel injection system 100 includes a water supply pump 61, a water supply pipe 62, check valves 63a and 63b, an accumulator 71, a high-pressure pump 72, a detector 81, and a controller 82. In fig. 1, solid arrows indicate the flow of fluid such as fuel and water, and broken arrows indicate electrical signal lines.

The fuel injection valves 20A, 20B, and 20C are examples of a plurality of fuel injection valves for injecting fuel and water into a combustion chamber (none of which is shown) in a cylinder of a marine diesel engine. Although not shown in fig. 1, the fuel injection valves 20A, 20B, and 20C are provided in one cylinder. For example, the fuel injection valves 20A, 20B, and 20C are arranged at predetermined intervals along the circumferential direction of the cylinder.

As shown in fig. 1, the fuel injection valve 20A has an injection port 21, a fuel passage 22 communicating with the injection port 21, an internal passage 23 communicating with the fuel passage 22, and check valves 24a, 24 b. One end of the fuel passage 22 is connected to the injection port 21 and the other end is connected to the fuel injection pipe 32 (for example, a branch pipe 32a thereof). Further, a pipe of the upstream side water injection system 50 (for example, the upstream side water injection pipe 52a) is connected to the upstream side water injection position (the second water injection position P2) of the fuel passage 22 via the check valve 24 a. One end of the internal passage 23 is connected to a water injection position (first water injection position P1) on the downstream side of the fuel passage 22, and the other end is connected to a pipe (for example, the downstream water injection pipe 42a) of the downstream side water injection system 40. The check valve 24a enables the water to flow from the upstream side water injection system 50 to the fuel passage 22 of the fuel injection valve 20A, and prevents the water from flowing backward. The check valve 24b is provided in the middle of the internal passage 23. The check valve 24b enables the water from the downstream water injection system 40 to flow through the internal passage 23 toward the fuel passage 22, and prevents the reverse flow thereof.

The fuel injection valve 20A having the above-described configuration injects fuel pressure-fed by the fuel pressure-feeding system 30, water injected by the downstream-side water injection system 40, and water injected by the upstream-side water injection system 50 in layers from the injection port 21 into the combustion chamber in the cylinder. The fuel injection valves 20B and 20C have the same structure as the fuel injection valve 20A described above.

The fuel pressure-feed system 30 is a device for pressure-feeding fuel to the fuel injection valves 20A, 20B, and 20C. As shown in fig. 1, the fuel pressure feed system 30 includes a fuel injection pump 31, a fuel injection pipe 32, and a control valve 35.

The fuel injection pump 31 is a hydraulically driven pump driven by the pressure of the hydraulic oil, and pumps fuel to the fuel injection valves 20A, 20B, and 20C through the fuel injection pipe 32. The pressure-feeding action of the fuel injection valve 31 is to perform the laminar injection of the fuel and water from the injection port 21 to the combustion chamber in the cylinder with respect to the fuel injection valves 20A, 20B, and 20C.

One end of the fuel injection pipe 32 is connected to a discharge port of the fuel injection pump 31. A branch portion 33 is provided in the middle of the fuel injection pipe 32. The fuel injection pipe 32 branches from the branch portion 33 toward the other end into a plurality of branch pipes (three branch pipes 32a, 32b, and 32c in the present embodiment). As shown in fig. 1, a branch pipe 32a of branch pipes 32a, 32b, and 32c of the fuel injection pipe 32 is connected to the fuel passage 22 of the fuel injection valve 20A, and the fuel injection pipe 32 communicates the fuel injection valve 20A with the fuel injection pump 31 via the branch pipe 32 a. Similarly, the remaining branch pipes 32B and 32C are connected to the fuel passages 22 of the fuel injection valves 20B and 20C, respectively.

The control valve 35 controls the supply of the working oil from the pressure accumulation portion 71 to the fuel injection pump 31. The control valve 35 is opened during the injection period in which the fuel and water are injected from the fuel injection valves 20A, 20B, and 20C into the combustion chamber, and supplies the working oil in the pressure accumulating portion 71 to the fuel injection pump 31. On the other hand, the control valve 35 is closed during the injection suspension period of the fuel injection valves 20A, 20B, and 20C, and stops the supply of the hydraulic oil from the pressure accumulator 71 to the fuel injection pump 31. The timing of the opening and closing drive of the control valve 35 is controlled by the control unit 82.

The downstream side water injection system 40 is a device for injecting water to a water injection position on the downstream side of each fuel passage 22 of the fuel injection valves 20A, 20B, and 20C. As shown in fig. 1, the downstream side water injection system 40 includes a first water injection pump 41, downstream side water injection pipes 42a, 42b, and 42c, check valves 44a, 44b, and 44c, and a control valve 45.

The first water injection pump 41 is an example of the water injection pump of the present embodiment. One end of the downstream water injection pipe 42a is connected to the first discharge port of the first water injection pump 41, and the other end is connected to the internal passage 23 of the fuel injection valve 20A. The first water injection pump 41 injects water to the water injection position (i.e., the first water injection position P1) on the downstream side of the fuel passage 22 by pressure-feeding water to the fuel passage 22 of the fuel injection valve 20A through the downstream water injection pipe 42a and the like. One end of the downstream water injection pipe 42B is connected to the second discharge port of the first water injection pump 41, and the other end is connected to the internal passage of the fuel injection valve 20B. As in the case of the fuel injection valve 20A, the first water injection pump 41 injects water into the first water injection position P1 of the fuel passage 22 of the fuel injection valve 20B through the downstream side water injection pipe 42B and the like. One end of the downstream water injection pipe 42C is connected to the third discharge port of the first water injection pump 41, and the other end is connected to the internal passage of the fuel injection valve 20C. As in the case of the fuel injection valve 20A, the first water injection pump 41 injects water into the first water injection position P1 of the fuel passage 22 of the fuel injection valve 20C through the downstream side water injection pipe 42C and the like.

For example, as shown in fig. 1, the check valves 44a, 44b, and 44c are provided at the inlet ends (the ends on the first water injection pump 41 side) of the downstream water injection pipes 42a, 42b, and 42c, respectively. The check valve 44a enables the water to flow from the first water injection pump 41 side toward the fuel injection valve 20A side, and prevents the water from flowing backward. The check valve 44B enables the water to flow from the first water injection pump 41 side toward the fuel injection valve 20B side, and prevents the reverse flow thereof. The check valve 44C enables the water to flow from the first water injection pump 41 side toward the fuel injection valve 20C side, and prevents the reverse flow thereof.

The control valve 45 controls the supply of the hydraulic oil from the pressure accumulator 71 to the first water injection pump 41. The control valve 45 is opened during a period (i.e., an injection suspension period) other than the period during which the fuel and the water are injected by the fuel injection valves 20A, 20B, and 20C, and supplies the hydraulic oil in the pressure storage portion 71 to the first water injection pump 41. On the other hand, the control valve 45 is closed during the injection of the fuel and the water, and stops the supply of the hydraulic oil from the pressure accumulator 71 to the first water injection pump 41. The timing of the opening and closing drive of the control valve 45 is controlled by the control unit 82.

The upstream side water injection system 50 is a device for injecting water to a water injection position on the upstream side of each fuel passage 22 of the fuel injection valves 20A, 20B, and 20C. As shown in fig. 1, the upstream side watering system 50 includes a second watering pump 51, upstream side watering pipes 52a, 52b, and 52c, check valves 54a, 54b, and 54c, and a control valve 55.

The second water injection pump 51 is an example of the water injection pump according to the present embodiment. One end of the upstream water injection pipe 52a is connected to the first discharge port of the second water injection pump 51, and the other end is connected to the fuel passage 22 of the fuel injection valve 20A via the check valve 24 a. The second water injection pump 51 injects water into the upstream water injection position (i.e., the second water injection position P2) of the fuel passage 22 by pressure-feeding water to the fuel passage 22 of the fuel injection valve 20A through the upstream water injection pipe 52a and the like. One end of the upstream water injection pipe 52B is connected to the second discharge port of the second water injection pump 51, and the other end is connected to the fuel passage 22 of the fuel injection valve 20B via a check valve (not shown). As in the case of the fuel injection valve 20A, the second water injection pump 51 injects water into the second water injection position P2 of the fuel passage 22 of the fuel injection valve 20B through the upstream side water injection pipe 52B and the like. One end of the upstream water injection pipe 52C is connected to the third discharge port of the second water injection pump 51, and the other end is connected to the fuel passage 22 of the fuel injection valve 20C via a check valve (not shown). As in the case of the fuel injection valve 20A, the second water injection pump 51 injects water into the second water injection position P2 of the fuel passage 22 of the fuel injection valve 20C through the upstream side water injection pipe 52C and the like.

For example, as shown in fig. 1, check valves 54a, 54b, and 54c are provided at the inlet end portions (end portions on the second water injection pump 51 side) of the upstream water injection pipes 52a, 52b, and 52c, respectively. The check valve 54a enables the water to flow from the second water injection pump 51 side toward the fuel injection valve 20A side, and prevents the water from flowing backward. The check valve 54B enables the water to flow from the second water injection pump 51 side toward the fuel injection valve 20B side, and prevents the reverse flow thereof. The check valve 54C enables the water to flow from the second water injection pump 51 side toward the fuel injection valve 20C side, and prevents the reverse flow thereof.

The control valve 55 controls the supply of the hydraulic oil from the pressure accumulator 71 to the second water injection pump 51. The control valve 55 is opened during the injection suspension period of the fuel injection valves 20A, 20B, and 20C, and supplies the hydraulic oil in the pressure storage portion 71 to the second water injection pump 51. On the other hand, the control valve 55 is closed during the injection period of the fuel and water by the fuel injection valves 20A, 20B, and 20C, and stops the supply of the hydraulic oil from the pressure accumulator 71 to the second water injection pump 51. The timing of the opening and closing operation of the control valve 55 is controlled by the control unit 82.

The water supply pump 61 is a pump for supplying water to be discharged to the first and second water injection pumps 41 and 51. One end of the water supply pipe 62 is connected to the water supply pump 61 and the other end is branched into branch pipes 62a and 62 b. One branch pipe 62a of the water supply pipe 62 is connected to the first water injection pump 41 via a check valve 63 a. The other branch pipe 62b of the water supply pipe 62 is connected to the second water injection pump 51 via a check valve 63 b. The water supply pump 61 supplies the water to be discharged to the first water injection pump 41 through a branch pipe 62a of the water supply pipe 62 or the like, and supplies the water to be discharged to the second water injection pump 51 through a branch pipe 62b of the water supply pipe 62 or the like. The check valve 63a enables the water to flow from the water supply pump 61 side to the first water injection pump 41 side, and prevents the water from flowing backward. The check valve 63b enables the water to flow from the water supply pump 61 side to the second water injection pump 51 side, and prevents the reverse flow thereof.

The pressure accumulation unit 71 accumulates the pressure of the hydraulic oil that operates the fuel pressure feed system 30, the downstream side water injection system 40, and the upstream side water injection system 50. As shown in fig. 1, the accumulator 71 accumulates the pressure of the hydraulic oil in an internal accumulator chamber by accumulating the hydraulic oil discharged (pressure-fed) from the high-pressure pump 72 through a pipe or the like. In this way, the pressure of the hydraulic oil accumulated in the pressure accumulation portion 71 is adjusted by the discharge amount of the hydraulic oil discharged from the high-pressure pump 72 to the pressure accumulation portion 71. The pressure of the hydraulic oil accumulated in the pressure accumulator 71 is commonly used for the operation of the fuel injection pump 31, the operation of the first water injection pump 41, and the operation of the second water injection pump 51.

The detection unit 81 detects a crank angle of a marine diesel engine (not shown). The detection unit 81 detects the crank angle with the lapse of time, and sends an electric signal indicating the detected crank angle to the control unit 82 each time.

The control unit 82 receives an electric signal from the detection unit 81, and controls the open/close driving of the control valve 35 of the fuel pressure-feed system 30 so that the control valve 35 is opened at a timing when the crank angle indicated by the received electric signal reaches a predetermined rotation angle. The control unit 82 controls the operation timing of the fuel injection pump 31, that is, the injection timing of the fuel and water from the fuel injection valves 20A, 20B, and 20C into the combustion chamber by controlling the opening/closing drive of the control valve 35. At this injection timing, the fuel pressure-fed from the fuel injection pump 31, the water discharged from the first water injection pump 41, and the water discharged from the second water injection pump 51 are injected in layers from the fuel injection valves 20A, 20B, and 20C into the combustion chamber by the pressure-fed action of the fuel injection pump 31. Subsequently, the fuel passages 22 and the fuel injection pipes 32 of the fuel injection valves 20A, 20B, and 20C are filled with the remaining fuel that is not injected.

In the injection suspension period of the fuel injection valves 20A, 20B, and 20C, the controller 82 controls the operation timings of the first and second water injection pumps 41 and 51 so that water is injected into the water injection position (first water injection position P1) on the downstream side and the water injection position (second water injection position P2) on the upstream side of each of the fuel passages 22 in a state filled with fuel. During the injection suspension period, the water discharged from the first water injection pump 41 and the water discharged from the second water injection pump 51 are injected into the first water injection position P1 and the second water injection position P2 of the fuel passages 22 of the fuel injection valves 20A, 20B, and 20C, respectively, at a pressure higher than the pressure (residual fuel pressure) of the fuel remaining in the fuel passages 22.

(Structure of Water injection pump)

Next, the structure of the water injection pump according to the embodiment of the present invention will be described. Fig. 2 is a schematic side sectional view showing a configuration example of a water injection pump according to an embodiment of the present invention. Fig. 3 is a schematic sectional view taken along line a-a of the water injection pump shown in fig. 2. Hereinafter, the first water injection pump 41 (see fig. 1) for injecting water into the first water injection position P1 of the fuel passages 22 of the fuel injection valves 20A, 20B, and 20C is exemplified as an example of the water injection pump according to the present embodiment. The second water injection pump 51 is similar in structure to the first water injection pump 41, except that the water injection position of each fuel passage 22 for the fuel injection valves 20A, 20B, and 20C is different from the first water injection pump 41 (i.e., the second water injection position P2).

The first water injection pump 41 is a hydraulically driven water injection pump that discharges water by the pressure of the hydraulic oil. As shown in fig. 2 and 3, the first water injection pump 41 includes a water cylinder 1, a hydraulic cylinder 5, a plurality of (three in the present embodiment) water piston portions 6a, 6b, and 6c, a hydraulic piston portion 7, a coupling portion 8, and an urging portion 9.

The water tank 1 is a hollow cylindrical member capable of accommodating the water piston portions 6a, 6b, and 6c so as to be capable of reciprocating. Specifically, as shown in fig. 2 and 3, the water tub 1 includes water discharge passages 2a, 2b, and 2c as internal passages for discharging water, and an internal space 4 continuous with the water discharge passages 2a, 2b, and 2 c.

The water discharge passages 2a, 2b, and 2c are examples of a plurality of water discharge passages that communicate with a plurality of fuel injection valves provided in one cylinder, respectively, via pipes. As shown in fig. 2 and 3, the water discharge passages 2a, 2b, and 2c are formed in a shape (for example, a cylindrical shape) in which the water piston portions 6a, 6b, and 6c can slide in the reciprocating direction, respectively. The water discharge passages 2a, 2b, and 2c temporarily store water to be discharged, which is supplied through a passage (not shown) formed inside the water tub 1. Although not shown in fig. 2 and 3, a downstream water injection pipe 42a shown in fig. 1 is connected to the discharge port 3a (first discharge port) of the water discharge passage 2 a. The water discharge passage 2a communicates with the fuel injection valve 20A through the downstream water injection pipe 42 a. A downstream water injection pipe 42b shown in fig. 1 is connected to the discharge port 3b (second discharge port) of the water discharge passage 2 b. The water discharge passage 2B communicates with the fuel injection valve 20B through the downstream water injection pipe 42B. A downstream water injection pipe 42c shown in fig. 1 is connected to the discharge port 3c (third discharge port) of the water discharge passage 2 c. The water discharge passage 2C communicates with the fuel injection valve 20C through the downstream water injection pipe 42C. These water discharge passages 2a, 2B, 2C communicate with the fuel injection valves 20A, 20B, 20C at the same fuel passage positions. For example, the water discharge passage 2a communicates with the first water filling position P1 of the fuel passage 22 of the fuel injection valve 20A. Similarly, the water discharge passage 2B communicates with the first water filling position P1 of the fuel passage 22 of the fuel injection valve 20B, and the water discharge passage 2C communicates with the first water filling position P1 of the fuel passage 22 of the fuel injection valve 20C.

The internal space 4 is a space for enabling the reciprocating movement of a plurality of (three in the present embodiment) water piston portions 6a, 6b, 6c in accordance with the operation of one hydraulic piston portion 7. As shown in fig. 2, the lower portions of the water piston portions 6a, 6b, and 6c, the upper portion of the hydraulic piston portion 7, and the connecting portion 8 connecting these portions are housed in the internal space 4 so as to be able to reciprocate.

The hydraulic cylinder 5 is a hollow cylindrical member capable of accommodating the hydraulic piston portion 7 so as to be capable of reciprocating. Specifically, as shown in fig. 2, the hydraulic cylinder 5 has a hydraulic oil chamber 5a for receiving hydraulic oil for operating the hydraulic piston portion 7. The hydraulic oil chamber 5a is formed to be able to house the hydraulic piston portion 7 so as to be able to reciprocate. The hydraulic cylinder 5 is coupled to the water cylinder 1 by a mounting bolt 10. The lower end of the hydraulic cylinder 5 is attached to hydraulic oil supply equipment such as the accumulator 71 and the control valve 45 shown in fig. 1.

The water piston portions 6a, 6b, and 6c are examples of a plurality of water piston portions that pressurize and discharge water in a plurality of water discharge passages to a plurality of fuel injection valves provided in one cylinder. In the present embodiment, the water piston portions 6a, 6b, and 6c are, for example, pistons having the same diameter, and are disposed in the water discharge passages 2a, 2b, and 2c so as to be able to reciprocate, as shown in fig. 2 and 3. Further, "the diameters of the water piston portions 6a, 6b, and 6c are the same as each other" means that the diameters of the water piston portions 6a, 6b, and 6c are within the range of manufacturing tolerance. The water piston portion 6a reciprocates in the piston axial direction (vertical direction on the paper of fig. 2) while sliding in the water discharge passage 2 a. At this time, the water piston 6a moves in the direction of the compressed water discharge passage 2a, and is pressurized to discharge the water in the water discharge passage 2 a. The water piston portion 6b reciprocates in the piston axial direction while sliding in the water discharge passage 2 b. At this time, the water piston 6b moves in the direction of the compressed water discharge passage 2b, and is pressurized to discharge the water in the water discharge passage 2 b. The water piston portion 6c reciprocates in the piston axial direction while sliding in the water discharge passage 2 c. At this time, the water piston 6c moves in the direction of the compressed water discharge passage 2c, and is pressurized to discharge the water in the water discharge passage 2 c. The water piston portions 6a, 6B, and 6C thus pressurize the water in the water discharge passages 2a, 2B, and 2C and discharge the water to the fuel injection valves 20A, 20B, and 20C, respectively.

The hydraulic piston portion 7 is a piston that operates by the pressure of the hydraulic oil. As shown in fig. 2, the hydraulic piston portion 7 is housed in a hydraulic chamber 5a of the hydraulic cylinder 5 so as to be capable of reciprocating in the piston axial direction. The hydraulic piston portion 7 moves the water piston portions 6a, 6b, and 6c toward the discharge ports 3a, 3b, and 3c of the water discharge passages 2a, 2b, and 2c, respectively, by the pressure of the hydraulic oil supplied to the hydraulic oil chamber 5 a. The hydraulic piston portion 7 moves (descends) in the piston axial direction while pushing out hydraulic oil from the hydraulic oil chamber 5a, and returns to the original position before the operation.

The connection portion 8 is an example of a connection portion that connects a plurality of hydraulic piston portions and one hydraulic piston portion. Specifically, as shown in fig. 2, the lower end portions of the water piston portions 6a, 6b, and 6c are fixed to one end surface of the coupling portion 8, and the upper end portion of the hydraulic piston portion 7 is fixed to the other end surface thereof, whereby the water piston portions 6a, 6b, and 6c and the hydraulic piston portion 7 are coupled and integrated. The coupling portion 8 is housed in the internal space 4 of the water tub 1 so as to be capable of reciprocating. The water piston portions 6a, 6b, and 6c fixed to the connection portion 8 are movable integrally with the hydraulic piston portion 7.

The biasing portion 9 biases the hydraulic piston portion 7 in a predetermined direction. The biasing portion 9 is formed of, for example, a compression spring, an air spring, or the like, and is provided above the hydraulic cylinder 5 as shown in fig. 2. A projection (not shown) of the hydraulic piston portion 7 is disposed on the biasing portion 9. The biasing portion 9 biases the hydraulic piston portion 7 in a direction (downward direction of the paper surface in fig. 2) in which the hydraulic oil is pushed out from the hydraulic oil chamber 5a by applying a biasing force to the protruding portion.

(operation of Water injection Pump)

Next, the operation of the water injection pump according to the embodiment of the present invention will be described. Fig. 4 is a diagram for explaining the operation of the water injection pump according to the embodiment of the present invention. The operation of the first water injection pump 41 will be described below with reference to fig. 4, and the first water injection pump 41 is an example of the operation of the water injection pump according to the present embodiment.

As shown in fig. 4, at a stage before the water is discharged, the first water injection pump 41 is in a state where the hydraulic piston portion 7 is positioned at a predetermined reference position (state S1). At this time, the water to be discharged is supplied from the water supply pump 61 shown in fig. 1 through the water supply pipe 62 and the like to the water discharge passages 2a, 2b, and 2 c. Thereby, the water discharge passages 2a, 2b, and 2c are filled with the water to be discharged.

Next, when the first water injection pump 41 discharges water, hydraulic oil is supplied from the pressure accumulator 71 shown in fig. 1 to the hydraulic oil chamber 5a of the hydraulic cylinder 5 through the control valve 45 and the like. As in the state S2 shown in fig. 4, the hydraulic piston portion 7 receives the pressure of the hydraulic oil in the hydraulic oil chamber 5a and moves (rises) toward the discharge ports 3a, 3b, and 3c of the water discharge passages 2a, 2b, and 2c by the pressure of the hydraulic oil. At this time, the hydraulic piston 7 moves the water piston portions 6a, 6b, and 6c toward the discharge ports 3a, 3b, and 3c together with the connecting portion 8 while overcoming the biasing force of the biasing portion 9. Thereby, the hydraulic piston portion 7 moves the water piston portions 6a, 6b, and 6c in the direction of the compressed water discharge passages 2a, 2b, and 2c by the same amount of rise (preferably, by the same volume).

By the action of the hydraulic piston portion 7, the water piston portions 6a, 6b, and 6c respectively pressurize the water (water to be discharged) in the water discharge passages 2a, 2b, and 2c while sliding in the water discharge passages 2a, 2b, and 2c by the same amount of movement (rise). The water in the water discharge passage 2a is pressurized by the water piston portion 6a, and flows into the downstream water injection pipe 42a by pressing open the check valve 44a shown in fig. 1 from the discharge port 3a, and is injected into the first water injection position P1 of the fuel passage 22 of the fuel injection valve 20A through the downstream water injection pipe 42 a. The water in the water discharge passage 2B is pressurized by the water piston portion 6B, and flows into the downstream water injection pipe 42B by pressing open the check valve 44B shown in fig. 1 from the discharge port 3B, and is injected into the first water injection position P1 of the fuel passage 22 of the fuel injection valve 20B through the downstream water injection pipe 42B. The water in the water discharge passage 2C is pressurized by the water piston portion 6C, and flows into the downstream water injection pipe 42C by pushing open the check valve 44C shown in fig. 1 from the discharge port 3C, and is injected into the first water injection position P1 of the fuel passage 22 of the fuel injection valve 20C through the downstream water injection pipe 42C.

The discharge of water by the first water injection pump 41 continues while the hydraulic oil is supplied to the hydraulic oil chamber 5a, that is, while the hydraulic piston portion 7 moves toward the discharge ports 3a, 3b, and 3c by the pressure of the hydraulic oil. Here, the respective rising amounts (preferably displacement volumes) of the water piston portions 6a, 6b, and 6c are forcibly made the same among the water discharge passages 2a, 2b, and 2c by the action of one hydraulic piston portion 7 common to the water piston portions 6a, 6b, and 6 c. As a result, the discharge amounts of the respective waters from the water discharge passages 2a, 2b, 2c are suppressed from being different (variation) among the water discharge passages 2a, 2b, 2c, and can be made equal to each other. That is, regardless of the variation (difference in level) in the residual fuel pressure among the fuel injection valves 20A, 20B, and 20C, the same amount of water can be injected into the first water injection position P1 from the water discharge passages 2a, 2B, and 2C to the fuel passages 22 of the fuel injection valves 20A, 20B, and 20C while suppressing the variation in the amount of injected water. As a result, the same amount of fuel and water can be injected in layers from the fuel injection valves 20A, 20B, and 20C into the combustion chamber in one cylinder between the fuel injection valves 20A, 20B, and 20C.

Subsequently, when the supply of the hydraulic oil into the hydraulic oil chamber 5a is stopped, the discharge of the primary water by the first water injection pump 41 is completed. At this time, the hydraulic piston portion 7 moves from the current raised position to the original reference position while pushing out the hydraulic oil in the hydraulic oil chamber 5a (hydraulic oil used for the above-described discharge of water) from the hydraulic oil chamber 5a to the outside of the hydraulic cylinder 5 by the biasing force of the biasing portion 9. With the movement of the hydraulic piston portion 7, the water piston portions 6a, 6b, and 6c move together with the connection portion 8 in a direction in which the compression of the water discharge passages 2a, 2b, and 2c (pressurization of water) is released, and return to the position before the water discharge as in a state S1 shown in fig. 4. The water to be discharged is supplied from the water supply pump 61 to the water discharge passages 2a, 2b, and 2c through the water supply pipe 62 and the like, and the water discharge passages 2a, 2b, and 2c are thereby returned to a state filled with the water to be discharged.

As described above, in the water injection pump according to the embodiment of the present invention, the plurality of water discharge passages communicating with the plurality of fuel injection valves provided in one cylinder through pipes are formed, the plurality of water piston portions are provided in the plurality of water discharge passages so as to be capable of reciprocating, the plurality of water piston portions are moved to the discharge outlet side of the plurality of water discharge passages by the hydraulic piston portions operated by the pressure of the hydraulic oil, and the plurality of water piston portions pressurize the water in the plurality of water discharge passages and discharge the water to the plurality of fuel injection valves, respectively, by the action of the hydraulic piston portions. In particular, in the present embodiment, the plurality of water piston portions and the hydraulic piston portion are connected by a connecting portion, whereby the plurality of water piston portions and the hydraulic piston portion move integrally.

Therefore, the plurality of water piston portions can be reciprocated by the same amount of elevation by the operation of one hydraulic piston portion. Accordingly, the plurality of water piston portions can be moved by the same volume in the direction of compressing the plurality of water discharge passages. As a result, since variation in the amount of water discharged between the plurality of water discharge passages can be suppressed, water can be injected to the plurality of fuel injection valves provided in one cylinder with a simple water injection mechanism configuration, and variation in the amount of water injected between the plurality of fuel injection valves can be suppressed.

Further, it is possible to suppress variation in the injection amount of the fuel injected from the plurality of fuel injection valves to the combustion chamber per one cycle of the marine diesel engine among the plurality of fuel injection valves. This can suppress variation in flame length and heat generation during combustion of fuel in the combustion chamber, and therefore can suppress variation in the amount of wear of parts associated with the combustion chamber, such as a cylinder and a piston, and can suppress a decrease in combustion efficiency of the marine diesel engine.

In the water injection pump according to the embodiment of the present invention, since the plurality of water piston portions are reciprocated by the operation of one hydraulic piston portion, the amount of lift of the plurality of water piston portions can be controlled in a unified manner by controlling the amount of lift of the hydraulic piston portion. Therefore, the control for making the rising amounts of the plurality of water piston portions equal to each other can be performed with a simple configuration.

In the above-described embodiment, the water injection pump that injects water into each of the fuel passages of the three fuel injection valves 20A, 20B, and 20C provided in one cylinder is illustrated, but the present invention is not limited to this. For example, the water injection pump according to the present invention may be configured to inject water into each of the fuel passages of two or more (a plurality of) fuel injection valves provided in one cylinder.

In the above-described embodiment, the water injection pump has been described as an example in which the three water piston portions 6a, 6b, and 6c are operated by the action of the single hydraulic piston portion 7, but the present invention is not limited to this. For example, the water injection pump according to the present invention may be configured to operate two or more (a plurality of) water piston portions by the action of one hydraulic piston portion. That is, in the present invention, the number of the water piston portions and the number of the water discharge passages may be set so as to correspond to the number of the fuel injection valves to be filled with water provided in one cylinder.

The present invention is not limited to the above-described embodiments, and a configuration in which the above-described respective components are appropriately combined is also included in the present invention. In addition, other embodiments, examples, operation techniques, and the like, which are made by those skilled in the art based on the above-described embodiments, are all included in the scope of the present invention.

Industrial applicability of the invention

As described above, the water injection pump according to the present invention is useful for injecting water into a fuel injection valve, and is particularly suitable for a water injection pump capable of injecting water into a plurality of fuel injection valves provided in one cylinder and suppressing variation in the amount of injected water among the plurality of fuel injection valves.

Description of the symbols

1 Water vat

2a, 2b, 2c water discharge passage

3a, 3b, 3c discharge port

4 inner space

5 Hydraulic cylinder

5a working oil chamber

6a, 6b, 6c water piston part

7 hydraulic piston part

8 connecting part

9 force application part

10 mounting bolt

20A, 20B, 20C fuel injection valve

21 injection nozzle

22 fuel path

23 internal passages

24a, 24b check valve

30 fuel pressure feed system

31 fuel injection pump

32 fuel injection pipe

32a, 32b, 32c branch pipes

33 branching part

35 control valve

40 downstream side water injection system

41 first water injection pump

42a, 42b, 42c downstream water injection pipe

44a, 44b, 44c check valve

45 control valve

50 upstream side water injection system

51 second water injection pump

52a, 52b, 52c upstream side water injection pipe

54a, 54b, 54c check valve

55 control valve

61 water supply pump

62 Water supply pipe

62a, 62b branch pipe

63a, 63b check valve

71 pressure accumulating part

72 high pressure pump

81 detection part

82 control part

100 fuel injection system

P1 first Water injection position

P2 second water injection position.

The claims (modification according to treaty clause 19)

(modified) a water injection pump, comprising:

a water tank having a plurality of water discharge passages that are respectively communicated with a plurality of fuel injection valves provided in one cylinder of a marine diesel engine via pipes;

a plurality of water piston portions which are provided in the plurality of water discharge passages so as to be capable of reciprocating, respectively, and which pressurize water in the plurality of water discharge passages and discharge the water to the plurality of fuel injection valves, respectively;

a hydraulic piston unit that moves the plurality of water piston units to a discharge port side of the plurality of water discharge passages by a pressure of hydraulic oil;

a coupling portion that couples the plurality of hydraulic piston portions and the hydraulic piston portion; and

a hydraulic cylinder that has a hydraulic oil chamber that accommodates the hydraulic piston portion so as to be capable of reciprocating, receives the hydraulic oil, and is connected to the water cylinder,

the water tank has an internal space continuous with the plurality of water discharge passages, and accommodates the connection portion in the internal space so as to be capable of reciprocating,

the plurality of water piston portions move integrally with the hydraulic piston portion.

(deletion)

(modified) the water injection pump of claim 1,

the plurality of water discharge passages communicate with the plurality of fuel injection valves at the same position of the fuel passage.

(as modified) the water injection pump of claim 1 or 3,

the plurality of water piston portions are pistons having the same diameter as each other.