CN111819355B - Water injection pump - Google Patents
Water injection pump Download PDFInfo
- Publication number
- CN111819355B CN111819355B CN201980017809.6A CN201980017809A CN111819355B CN 111819355 B CN111819355 B CN 111819355B CN 201980017809 A CN201980017809 A CN 201980017809A CN 111819355 B CN111819355 B CN 111819355B
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- water
- pump housing
- plunger
- air
- hydraulic oil
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M43/00—Fuel-injection apparatus operating simultaneously on two or more fuels, or on a liquid fuel and another liquid, e.g. the other liquid being an anti-knock additive
- F02M43/02—Pumps peculiar thereto
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
- F02M59/46—Valves
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Details Of Reciprocating Pumps (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
A water injection pump according to an aspect of the present invention includes a pump housing and a plunger, and moves the plunger in the pump housing toward a discharge port by a pressure of hydraulic oil to pressurize water to be discharged and discharge the water. The pump housing is provided with: a drain discharge portion for discharging water flowing down in a gap between an outer circumferential surface of the plunger and an inner circumferential surface of the pump housing; and an air spring for returning the plunger to a reference position before the water to be discharged is discharged by moving the plunger after the water to be discharged is discharged to a side of the pump housing opposite to the discharge port side. The air spring is configured by supplying air having a pressure higher than the internal pressure of the drain discharge portion to an air chamber located below the drain discharge portion and surrounded by the outer peripheral surface of the plunger and the inner peripheral surface of the pump housing.
Description
Technical Field
The invention relates to a water injection pump.
Background
Conventionally, a fuel injection pump for injecting fuel into a cylinder has been applied to a marine diesel engine mounted on a ship. In general, a fuel injection pump includes a pump housing having a hollow cylindrical shape and a plunger (piston) provided in the pump housing so as to be capable of reciprocating, and pressurizes and discharges fuel by moving the plunger toward a discharge port side of the pump housing by pressure of hydraulic oil. The fuel discharged from the fuel injection pump is pressure-fed to a fuel injection valve provided in the cylinder through a pipe or the like, and is injected from an injection port of the fuel injection valve into a combustion chamber in the cylinder.
Further, as disclosed in patent document 1, for example, the fuel injection pump includes a compression spring (coil spring) that biases the plunger toward a side of the pump housing opposite to the injection port side. After the fuel is discharged as described above, the plunger returns to the original position (hereinafter, appropriately referred to as a reference position) before the fuel is discharged, while moving in the direction in which the hydraulic oil is pushed out from the pump housing by the biasing force of the compression spring.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2017-31918
Problems to be solved by the invention
In the field of ships, Nitrogen Oxides (NO) in exhaust gas discharged from a diesel engine for ships have been reduced in the pastx) One of the methods of (1), the water technology is proposed. The water technique reduces NO by adding water to a combustion chamber within a cylinder, thereby reducing the combustion temperature of the fuel within the combustion chamberxThe discharge amount of (2). In such a water technique, a hydraulically driven water injection pump using the pressure of the hydraulic oil is generally used to inject water into the fuel before injection (a fuel column present in a fuel flow passage such as a fuel injection valve) or to separately inject (inject) water into a combustion chamber.
The hydraulically driven water injection pump can be easily configured by, for example, adopting the structure of the fuel injection pump described above and replacing the discharge target with water from the fuel. However, in such a water injection pump, water remaining in the pump housing may pass through a gap between the outer wall surface of the plunger and the inner wall surface of the pump housing and then come into contact with the compression spring. Even if the gap is sealed by the seal member, there is a possibility that the seal of the gap cannot be maintained if the seal member is worn or damaged due to repeated sliding of the plunger, which reciprocates every time water is discharged, on the seal member. Therefore, it is necessary to take measures to prevent corrosion and damage due to contact between the compression spring and water, to the compression spring for returning the plunger after the water is discharged to the reference position. For example, by taking a measure such as making the material of the compression spring SUS, the corrosion of the compression spring can be prevented. However, in this case, the water injection pump main body is enlarged, which leads to an increase in cost of the water injection pump. Further, there is a problem that the degree of freedom of the arrangement space of the water injection pump is reduced.
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 including: the compression spring for returning the plunger after water discharge to the reference position is prevented from being corroded or damaged by water, and is small and low in cost.
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 pump housing and a plunger provided in the pump housing so as to be capable of reciprocating, and pressurizes water to be discharged in the pump housing by moving the plunger to a discharge port side of the pump housing by a pressure of hydraulic oil, wherein the pump housing includes: a drain discharge portion for discharging water flowing down in a gap between an outer circumferential surface of the plunger and an inner circumferential surface of the pump housing; and an air spring configured to return the plunger to a reference position before the water to be ejected is ejected by moving the plunger after the water to be ejected is ejected to a side opposite to an ejection outlet side of the pump housing, wherein the air spring is configured to supply air having a pressure higher than an internal pressure of the drain discharge portion to an air chamber which is a space surrounded by an outer peripheral surface of the plunger and an inner peripheral surface of the pump housing and is located below the drain discharge portion.
In the water injection pump according to the present invention, the pump housing includes a hydraulic oil discharge portion for discharging hydraulic oil remaining in the pump housing below the air chamber, and the air chamber is located between the drain discharge portion on the upper side and the hydraulic oil discharge portion on the lower side.
In addition, the water injection pump according to the present invention is characterized in that the above-described invention includes: a first seal member provided between the drain discharge portion and the air chamber, and closing a gap between an outer peripheral surface of the plunger and an inner peripheral surface of the pump housing and communication between the air chamber; and a second sealing member provided below the air chamber and closing communication between the air chamber and a lower internal space of the pump housing located below the air chamber.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, the following effects are obtained: a water injection pump which is small in size and inexpensive and can avoid corrosion and damage of a compression spring for returning a plunger to a reference position after water is discharged, the compression spring being corroded and damaged by water.
Drawings
Fig. 1 is a schematic sectional view showing a structural example of a water injection pump according to an embodiment of the present invention.
Fig. 2 is a diagram for explaining the operation of the water injection pump according to the embodiment of the present invention.
Fig. 3 is a diagram for explaining the operation of the air spring 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 Water injection pump)
Fig. 1 is a schematic sectional view showing a configuration example of a water injection pump according to an embodiment of the present invention. In the present embodiment, a case where the water injection pump 10 injects water into a fuel flow path of a marine diesel engine (not shown) is exemplified. Although not particularly shown, the fuel flow passage of the marine diesel engine is a flow passage of fuel that reaches the injection port of the fuel injection valve from the discharge port of the fuel injection pump through a pipe. A fuel injection pump is a device for injecting fuel through a pipe or the like to a fuel injection valve for injecting fuel into a cylinder of a marine diesel engine.
The water injection pump 10 is a hydraulically driven water injection pump that discharges water by using the pressure of the hydraulic oil, and includes, as shown in fig. 1, a pump housing 1, a plunger 6, seal rings 7 and 8 for closing a gap between the pump housing 1 and the plunger 6, a detection unit 9 for detecting the amount of movement (lift amount) of the plunger 6, and a water supply unit 17 for supplying water into the pump housing 1. The pump housing 1 includes a drain/drain portion 11, a hydraulic oil drain portion 12, an air spring 13 for applying a biasing force to the plunger 6, an air chamber 14 for constituting the air spring 13, an air flow path 15a, and an air inlet/outlet 15 b.
The pump housing 1 is, for example, a hollow cylindrical pump housing, and is formed by combining a plurality of cylindrical members having a hollow cylindrical shape. In the present embodiment, as shown in fig. 1, the pump casing 1 is composed of a discharge portion 2, a mounting table portion 3, a support portion 4, and a discharge valve portion 5.
As shown in fig. 1, the discharge portion 2 is a hollow cylindrical member and has an internal space capable of accommodating a water piston portion 6a of the plunger 6 so as to be capable of reciprocating. The discharge portion 2 has, as the discharge chamber 2a, a space portion surrounded by the lower end portion of the discharge valve portion 5 and the upper end portion of the water piston portion 6a in the internal space. The discharge chamber 2a is a space for temporarily storing water to be discharged. Although not particularly shown, the ejection unit 2 is coupled to the support unit 4 by a coupling member such as a bolt.
The mount base 3 is a housing portion for mounting the water injection pump 10 to a hydraulic oil supply device (not shown) such as a pressure reservoir portion for accumulating the pressure of the hydraulic oil. As shown in fig. 1, the mounting table portion 3 is formed in a hollow cylindrical shape, for example, and has a hydraulic oil chamber 3a, which is an internal space for receiving hydraulic oil for operating the plunger 6. The hydraulic oil chamber 3a is formed to be able to accommodate a hydraulic oil piston portion 6b of the plunger 6 so as to be able to reciprocate. Although not particularly shown, the mount base portion 3 is coupled to the support portion 4 by a coupling member such as a bolt.
The support portion 4 is a housing portion for supporting the plunger 6 and the detection portion 9 provided in the pump housing 1. As shown in fig. 1, the support portion 4 is formed in a hollow cylindrical shape, for example, and has an internal space capable of accommodating a middle portion of the plunger 6 (in the present embodiment, a lower portion of the water piston portion 6a, the restricting portion 6c, and the force receiving portion 6d) so as to be capable of reciprocating. The support portion 4 has a space portion between the upper seal ring 7 and the lower seal ring 8 in the internal space as an air chamber 14, and a space portion below the air chamber 14 as a lower internal space 4 a. The support portion 4 slidably supports the plunger 6 in the axial direction F1 via the seal rings 7 and 8 so that the regulating portion 6c and the receiving portion 6d of the plunger 6 face the inside of the air chamber 14. The support portion 4 supports the detection portion 9 such that a detection terminal of the detection portion 9 is housed in the lower internal space 4 a.
As shown in fig. 1, the discharge valve portion 5 is attached to the upper end portion of the discharge portion 2 by fitting or the like. For example, the discharge valve portion 5 has a check valve 5a and a discharge port 5b, the check valve 5a is formed in a hollow cylindrical shape and communicates with the discharge chamber 2a of the discharge portion 2, and the discharge port 5b communicates with the outlet side of the check valve 5 a. The discharge valve portion 5 is provided with a water injection pipe (not shown) communicating with the discharge port 5 b. The check valve 5a restricts the water discharge direction of the water injection pump 10 to a predetermined direction (a direction from the discharge chamber 2a side to the discharge port 5b side in fig. 1), and prevents the water from flowing backward. The discharge port 5b guides the water discharged from the discharge chamber 2a via the check valve 5a into the water filling pipe.
The plunger 6 is used to pressurize water to be discharged by the pressure of the hydraulic oil and discharge the water. As shown in fig. 1, the plunger 6 is a cylindrical member including a water piston portion 6a, a hydraulic oil piston portion 6b, a restricting portion 6c, a force receiving portion 6d, and a tapered portion 6e, and is disposed in the pump housing 1 so as to be capable of reciprocating.
The water piston portion 6a is a portion for pressurizing and discharging water to be discharged. The water piston portion 6a is provided on one end side (upper side in fig. 1) in the axial direction F1 of the plunger 6. As shown in fig. 1, the water piston portion 6a is accommodated in an internal space of the pump housing 1 continuing from the discharge portion 2 to the support portion 4, and is supported by the support portion 4 via the seal ring 7. The water piston portion 6a reciprocates in the axial direction F1 of the plunger 6 while sliding on the seal ring 7. At this time, the water piston portion 6a moves in a direction to compress the discharge chamber 2a, and pressurizes the water in the discharge chamber 2a (i.e., the water to be discharged) to discharge the water. In the present embodiment, the upper end surface of the water piston portion 6a serves as a pressurizing surface for pressurizing water to be discharged.
The hydraulic oil piston portion 6b is a portion for receiving the pressure of the hydraulic oil for operating the plunger 6. The hydraulic oil piston portion 6b is provided on the other end side (lower side in fig. 1) in the axial direction F1 of the plunger 6. As shown in fig. 1, the hydraulic piston portion 6b is housed in an internal space (hydraulic oil chamber 3a) of the mounting table portion 3 so as to be capable of reciprocating in an axial direction F1 of the plunger 6. The hydraulic oil piston portion 6b receives the pressure of the hydraulic oil supplied to the hydraulic oil chamber 3a, and is moved (raised) from the reference position Ps toward one end side of the plunger 6 in the axial direction F1 by the pressure of the hydraulic oil. In the present embodiment, the lower end surface of the hydraulic oil piston portion 6b serves as a pressure receiving surface that receives the pressure of the hydraulic oil. The hydraulic oil piston portion 6b moves (descends) toward the other end side of the plunger 6 in the axial direction F1 while pushing out the hydraulic oil in the hydraulic oil chamber 3a toward the hydraulic oil supply device, and returns to the reference position Ps.
The reference position Ps is an original position of the plunger 6 before the water injection pump 10 ejects water. The plunger 6 reciprocates in the axial direction F1 starting from the reference position Ps. In the present embodiment, the reference position Ps is determined by, for example, the height position of the lower end surface of the plunger 6 (i.e., the lower end surface of the hydraulic oil piston portion 6 b).
The restricting portion 6c, the force receiving portion 6d, and the tapered portion 6e are provided between the water piston portion 6a and the hydraulic oil piston portion 6b along the axial direction F1 of the plunger 6. As shown in fig. 1, the restricting portion 6c is formed at the lower end portion of the water piston portion 6a so as to have a larger outer diameter than the water piston portion 6 a. The restriction portion 6c restricts the range of movement of the plunger 6 toward the discharge port 5b side by abutting against the inner wall surface of the air chamber 14 when the plunger 6 moves toward the discharge port 5b side (upper side in the axial direction F1) of the pump housing 1.
As shown in fig. 1, the force receiving portion 6d is formed at the lower end portion of the regulating portion 6c so as to have a larger outer diameter than the regulating portion 6 c. In the present embodiment, the upper edge of the force receiving portion 6d serves as a portion that receives the biasing force of the air spring 13. When the plunger 6 moves toward the discharge port 5b of the pump housing 1, the force receiving portion 6d moves toward the discharge port 5b against the biasing force of the air spring 13. When the plunger 6 returns to the reference position Ps, the force receiving portion 6d receives the biasing force of the air spring 13 and moves toward the reference position Ps.
As shown in fig. 1, the tapered portion 6e is formed between the force receiving portion 6d and the hydraulic oil piston portion 6b such that the outer diameter thereof decreases from the upper side toward the lower side of the axial direction F1 of the plunger 6. The tapered portion 6e is used for detection of the lifting amount of the plunger 6 by the detection portion 9.
The plunger 6 having the above-described configuration receives the pressure of the hydraulic oil from the hydraulic oil piston portion 6b, and moves toward the discharge port 5b of the pump housing 1 by the pressure of the hydraulic oil. Thereby, the plunger 6 pressurizes and discharges the water in the discharge chamber 2a by the water piston portion 6 a. The plunger 6 receives the urging force of the air spring 13 through the force receiving portion 6d, and moves to the opposite side of the discharge port 5b by the urging force. Thereby, the plunger 6 pushes out the hydraulic oil in the hydraulic oil chamber 3a by the hydraulic oil piston portion 6b and returns to the reference position Ps.
The seal rings 7 and 8 are seal members for closing a gap between the inner peripheral surface of the pump housing 1 and the outer peripheral surface of the plunger 6 (hereinafter, referred to simply as a gap in the pump housing as appropriate). As shown in fig. 1, the seal ring 7 (first seal member) is provided between the drain portion 11 (e.g., drain trap portion 11a) and the air chamber 14, for example, by fitting into a recess or the like formed along the inner peripheral surface of the support portion 4 of the pump housing 1. Here, the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1 is continuous with the air chamber 14 in the internal space of the pump housing 1, and the air chamber 14 is a space surrounded by the outer peripheral surface of the middle portion of the plunger 6 and the inner peripheral surface of the support portion 4 of the pump housing 1. The seal ring 7 closes the communication between the gap 18 in the pump housing 1 and the air chamber 14. Thereby, the seal ring 7 airtightly separates the gap 18 in the pump housing 1 from the air chamber 14 at a position between the drain discharge portion 11 and the air chamber 14.
As shown in fig. 1, the seal ring 8 (second seal member) is provided below the air chamber 14, for example, by fitting into a recess formed along the outer peripheral surface of the force receiving portion 6d of the plunger 6. Here, the lower side of the air chamber 14 is continuous with the lower inner space 4a in the support portion 4 of the pump housing 1. The seal ring 8 closes the communication between the lower internal space 4a and the air chamber 14. As a result, as shown in fig. 1, the lower internal space 4a facing the hydraulic oil discharge portion 12 is air-tightly separated from the air chamber 14 by the seal ring 8.
The detection unit 9 is a device for detecting the lift amount of the plunger 6 in one ejection of water by the water injection pump 10. As shown in fig. 1, the detection unit 9 is supported by the support unit 4 of the pump housing 1 so as to face the tapered portion 6e of the plunger 6. In the present embodiment, the pair of detection portions 9 are disposed so as to face each other in the radial direction F2 of the plunger 6 with the tapered portion 6e interposed therebetween in the lower internal space 4a of the pump housing 1. The detection unit 9 detects (measures) a distance between the tapered portion 6e and the plunger 6e, which changes due to movement (lifting). The lift amount of the plunger 6 is calculated based on the detected distance and the inclination angle of the tapered portion 6 e. The lift amount is an example of the amount of movement of the plunger 6 that moves in the direction in which the water to be discharged is pressurized (upward in the present embodiment) in one water discharge by the water injection pump 10.
The drain discharge portion 11 is for discharging water flowing down in a gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1. As shown in fig. 1, the drain portion 11 is composed of a drain trap portion 11a and a drain passage 11b, and is provided in a portion of the pump housing 1 above the air chamber 14. The drain trap portion 11a is provided in the support portion 4 of the pump housing 1 (in the present embodiment, a boundary portion where the discharge portion 2 and the support portion 4 are joined) so as to communicate with a gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1. The drain trap portion 11a traps water flowing down through a gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1. The drainage channel 11b is provided in the support portion 4 so that the drainage trap portion 11a communicates with the outside of the pump housing 1. Although not particularly shown, a drain pipe is connected to an outlet portion of the drain passage 11 b. The drain discharge portion 11 collects water that leaks from the discharge chamber 2a in the pump housing 1 to the gap 18 without being discharged from the water injection pump 10 and flows down through the gap 18, in the water in the discharge chamber 2a, into the drain collection portion 11a, and discharges the collected water from the inside of the pump housing 1 to an external water distribution pipe through the drain passage 11 b.
The working oil discharge portion 12 is for discharging the working oil remaining in the pump housing 1. As shown in fig. 1, the hydraulic oil discharge portion 12 is constituted by a hydraulic oil collecting portion 12a and a hydraulic oil discharge passage 12b, and is provided in a lower portion of the pump housing 1 than the air chamber 14. The working oil collecting portion 12a is provided at a predetermined portion of the pump housing 1 (in the present embodiment, a boundary portion where the support portion 4 and the mounting portion 3 are joined) so as to communicate with the lower internal space 4a of the pump housing 1. The working oil collecting portion 12a collects the working oil that leaks from the working oil chamber 3a to the lower internal space 4a along the outer peripheral surface of the working oil piston portion 6 b. The hydraulic oil discharge passage 12b is provided in the pump housing 1 (the mount section 3 in the present embodiment) so that the hydraulic oil collecting section 12a communicates with the outside of the pump housing 1. Although not particularly shown, a hydraulic oil discharge pipe is connected to an outlet portion of the hydraulic oil discharge path 12 b. The hydraulic oil discharge unit 12 collects, among the hydraulic oil in the hydraulic oil chamber 3a, the hydraulic oil that is not pushed out from the water injection pump 10 and remains in the lower internal space 4a of the pump housing 1, into the hydraulic oil collection unit 12a, and discharges the collected hydraulic oil from the inside of the pump housing 1 to an external hydraulic oil discharge pipe through the hydraulic oil discharge passage 12 b. In the present embodiment, the used hydraulic oil discharged to the hydraulic oil discharge pipe is discarded without being used.
The air spring 13 is for applying a force to the plunger 6 to urge the plunger toward the reference position Ps. As shown in fig. 1, the air spring 13 is constituted by air in an air chamber 14 formed in the pump housing 1. The air chamber 14 is a space surrounded by the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1, and is located below the drainage drain portion 11 (for example, below the drainage trap portion 11 a). In the present embodiment, the air chamber 14 is located between the upper drain and drain portion 11 and the lower hydraulic oil drain portion 12. The upper side of the air chamber 14 is closed by a seal ring 7, and the lower side of the air chamber 14 is closed by a seal ring 8. The air spring 13 is configured by supplying air having a pressure higher than the internal pressure of the drain discharge portion 11 to the air chamber 14. For example, when the internal pressure of the drain port 11 is atmospheric pressure, 0.5MPa of air is supplied to the air chamber 14. The air spring 13 applies the above-described urging force to the force receiving portion 6d of the plunger 6. The air spring 13 moves the plunger 6 after the water to be discharged is discharged (i.e., the plunger 6 after the plunger 6 has moved in the direction of compressing the discharge chamber 2 a) to the side opposite to the discharge port 5b side of the pump housing 1 by the biasing force applied to the force receiving portion 6 d. Thereby, the air spring 13 returns the plunger 6 to the reference position Ps before the water to be discharged is discharged.
The pump housing 1 (the support portion 4 in the present embodiment) is provided with an air flow path 15a and an air inlet/outlet 15b for allowing air to enter and exit the air chamber 14. As shown in fig. 1, an air pipe 16 is connected to a portion of the pump housing 1 where the air inlet and outlet 15b is formed. The air flow passage 15a communicates the air chamber 14 with the air pipe 16 via an air inlet/outlet 15 b. The air inlet/outlet 15b is formed of an opening member having a small opening size such as an orifice. The air inlet/outlet 15b keeps the pressure of air in the air chamber 14 (i.e., the air pressure of the air spring 13) at a predetermined value or more, and allows air to enter/exit the air chamber 14 and the air pipe 16 through the air flow passage 15 a. In the present embodiment, the pressure of the air in the air chamber 14 is higher than the internal pressure of the gap 18 in the pump housing 1 communicating with the drain 11 and the internal pressure of the lower internal space 4a communicating with the hydraulic oil drain 12.
The water supply unit 17 is provided in the pump housing 1 so as to communicate with the discharge chamber 2a, for supplying water into the discharge chamber 2a of the pump housing 1. Water to be discharged is supplied from water supply unit 17 to discharge chamber 2a through a pipe of a tank (not shown) or the like. Every time water is discharged by the water injection pump 10, water to be discharged is supplied (replenished) to the discharge chamber 2a by the water supply unit 17.
(operation of Water injection Pump)
Fig. 2 is a diagram for explaining the operation of the water injection pump according to the embodiment of the present invention. In the present embodiment, the water injection pump 10 pressurizes and discharges water to be discharged in the pump housing 1 by moving the plunger 6 toward the discharge port 5b of the pump housing 1 by the pressure of the hydraulic oil.
Specifically, as shown in fig. 2, the water injection pump 10 is in a state (state 1) in which the plunger 6 is positioned at the reference position Ps in a stage before the water is discharged. At this time, water to be discharged is supplied to the discharge chamber 2a of the pump housing 1 through the water supply unit 17. Thereby, the discharge chamber 2a is filled with the water to be discharged. Air at a pressure equal to or higher than a predetermined value is supplied from the air pipe 16 to the air chamber 14 through the air inlet/outlet 15b and the air flow passage 15 a. Thereby, the air spring 13 that biases the plunger 6 toward the reference position Ps is configured in the air chamber 14.
Next, when the water injection pump 10 discharges water, the hydraulic oil is supplied to the hydraulic oil chamber 3a of the pump housing 1 through a control valve (not shown) of the hydraulic oil supply device or the like. The plunger 6 receives the pressure of the hydraulic oil in the hydraulic oil chamber 3a by the hydraulic oil piston portion 6b, and moves toward the discharge port 5b of the pump housing 1 (upward in the axial direction F1 shown in fig. 1) by the pressure of the hydraulic oil. At this time, the plunger 6 moves against the urging force of the air spring 13 applied to the force receiving portion 6d while sliding the outer peripheral surface of the water piston portion 6a on the seal ring 7 on the inner peripheral surface of the pump housing 1 and sliding the seal ring 8 of the force receiving portion 6d on the inner peripheral surface of the pump housing 1. Thus, the plunger 6 pressurizes (e.g., to about 15 MPa) the water (water to be discharged) in the discharge chamber 2a by the water piston portion 6 a. The pressurized water to be discharged pushes open the check valve 5a to flow to the discharge port 5b, and is injected from the discharge port 5b into a fuel flow passage (not shown) of the marine diesel engine through a water injection pipe (not shown). The water injection by the water injection pump 10 is continuously performed while the hydraulic oil is supplied to the hydraulic oil chamber 3a, that is, while the plunger 6 is moved by the pressure of the hydraulic oil to pressurize the water in the discharge chamber 2 a. The jetting of the water causes the columnar fuel and the columnar water to alternately exist along the fuel flow path. As a result, fuel and water can be injected in layers into the cylinder of the marine diesel engine.
The air spring 13 is pressed by the force receiving portion 6d in accordance with the movement of the plunger 6. At this time, the high-pressure air constituting the air spring 13 flows out from the air chamber 14 to the air pipe 16 through the air flow passage 15a and the air inlet/outlet 15 b. The plunger 6 is in a state of moving from the reference position Ps to the lift position P1 (state 2). The amount of movement (amount of lift) of the plunger 6 is detected by the detector 9. The movement of the plunger 6 is restricted by the contact of the restricting portion 6c with the air chamber 14.
Thereafter, when the supply of the hydraulic oil into the hydraulic oil chamber 3a is stopped, the water injection pump 10 finishes the discharge of a single amount of water. At this time, air at a pressure equal to or higher than a predetermined value is supplied from the air pipe 16 to the air chamber 14 through the air inlet/outlet 15b and the air passage 15 a. The air spring 13, which is made of air supplied into the air chamber 14, applies a biasing force toward the reference position Ps to the force receiving portion 6d, thereby moving the plunger 6 toward the reference position Ps. The plunger 6 moves from the lift position P1 toward the reference position Ps while pushing out the hydraulic oil (the hydraulic oil used for the above-described water discharge) in the hydraulic oil chamber 3a from the hydraulic oil chamber 3a to the outside (the hydraulic oil supply device side) of the pump housing 1 by the biasing force of the air spring 13. As a result, the plunger 6 releases the compression of the discharge chamber 2a by the water piston portion 6a (pressurization of water), and returns to the reference position Ps before the discharge of water is performed as in state 1 shown in fig. 2. By supplying water to be discharged to the discharge chamber 2a through the water supply unit 17, the discharge chamber 2a is returned to a state filled with water to be discharged.
(action of air spring)
Fig. 3 is a diagram for explaining an operation of the air spring in the embodiment of the present invention. In the present embodiment, as described above, the air spring 13 applies the biasing force to the force receiving portion 6d of the plunger 6, thereby moving the plunger 6 to the side opposite to the discharge port 5b side of the pump housing 1 and returning to the reference position Ps. In addition to this action, the air spring 13 prevents water flowing down from the discharge chamber 2a through the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1 from mixing with the hydraulic oil in the pump housing 1.
Specifically, as shown in fig. 3, the air spring 13 is configured by supplying air having a pressure equal to or higher than a predetermined value to the air chamber 14. The air pressure of the air spring 13 is greater than the internal pressure of the drain 11. That is, the air pressure of the air spring 13 is higher than the internal pressure of the gap 18 in the pump housing 1 communicating with the drain trap portion 11a and the drain passage 11b of the drain portion 11. The air pressure of the air spring 13 is higher than the internal pressure of the hydraulic oil discharge portion 12. That is, the air pressure of the air spring 13 is higher than the internal pressure of the lower internal space 4a in the pump housing 1 communicating with the hydraulic oil collecting portion 12a of the hydraulic oil discharge portion 12 and the hydraulic oil discharge passage 12 b.
As shown in fig. 3, the upper side of the air chamber 14 is closed by the seal ring 7, and the lower side of the air chamber 14 is closed by the seal ring 8. The upper seal ring 7 separates the gap 18 in the pump housing 1 from the air chamber 14 in a liquid-tight (preferably airtight) manner at a position lower than the drain discharge portion 11. The lower seal ring 8 separates the lower internal space 4a of the pump housing 1 from the air chamber 14 in a liquid-tight (preferably airtight) manner at a position above the hydraulic oil discharge portion 12.
Here, in the pump housing 1, a part of the water to be discharged, which is supplied into the discharge chamber 2a (see fig. 1), may leak from the discharge chamber 2a to the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1 without being discharged. As shown in fig. 3, the water 19 leaked into the gap 18 in the pump housing 1 flows down through the gap 18 toward the air chamber 14. The water 19 in the gap 18 is normally prevented from flowing down by the upper seal ring 7. As a result, the water 19 in the gap 18 flows into the drain trap portion 11a without entering the air chamber 14, and is discharged to the outside of the pump housing 1 through the drain passage 11 b. That is, in the pump housing 1, the water 19 in the gap 18 does not flow into the lower internal space 4a nor through the air chamber 14. Therefore, the water 19 in the gap 18 does not come into contact with the detection portion 9 facing the lower internal space 4a, and is not mixed with the hydraulic oil in the hydraulic oil discharge portion 12 and the hydraulic oil in the hydraulic oil chamber 3 a.
If the upper seal ring 7 is worn or damaged by sliding of the plunger 6, the upper seal ring 7 may not completely prevent the water 19 flowing down through the gap 18 in the pump housing 1. Even in such a case, the air spring 13 can prevent the water 19 in the gap 18 from flowing down by the air pressure thereof, and can flush the water 19 from the gap 18 toward the drain water collection portion 11 a. In this way, the air spring 13 prevents the water 19 in the gap 18 from flowing into the lower internal space 4a through the air chamber 14. As a result, the detection unit 9 can be prevented from contacting the water 19 and causing a failure, and the water 19 can be prevented from mixing into the hydraulic oil in the pump housing 1. Even when the lower seal ring 8 is damaged by, for example, sliding of the plunger 6, the air spring 13 can prevent the hydraulic oil from entering the air chamber 14 from the lower internal space 4a by the air pressure. In this case, the air spring 13 can prevent the working oil and the water 19 in the pump housing 1 from being mixed.
As described above, in the water injection pump 10 according to the embodiment of the present invention, the air chamber 14 surrounded by the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1 is formed in the pump housing 1 at a position lower than the drain discharge portion 11 that discharges the water 19 flowing down through the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump housing 1, the air spring 13 is configured by supplying air having a pressure higher than the internal pressure of the drain discharge portion 11 to the air chamber 14, and the plunger 6 after the water to be discharged is returned to the reference position Ps before the water to be discharged is discharged by the biasing force of the air spring 13.
Therefore, the water injection pump can be configured simply without using a compression spring such as a coil spring, and the plunger moved to the discharge port side for discharging water can be returned to the reference position before the movement. As a result, it is not necessary to take measures against corrosion and damage of the compression spring conventionally used for returning the plunger to the reference position after the water discharge, and a small-sized and inexpensive water injection pump can be provided.
The air spring 13 is made of air having a pressure higher than the internal pressure of the drain port 11. Therefore, even when the seal ring 7 provided above the air chamber 14 is damaged, the air pressure of the air spring 13 can prevent the water 19 from flowing down through the gap 18 in the pump housing 1 communicating with the drain 11. This can prevent the water 19 in the gap 18 from flowing into the lower internal space 4a of the pump housing 1 through the air chamber 14. As a result, it is possible to prevent equipment such as the detection unit 9 facing the lower internal space 4a from coming into contact with the water 19 and causing a failure, and also prevent the water 19 from being mixed into the hydraulic oil in the pump housing 1.
In the water injection pump 10 according to the embodiment of the present invention, the hydraulic oil discharge portion 12 for discharging the hydraulic oil remaining in the pump housing 1 is provided at a position lower than the air chamber 14 in the pump housing 1, and the air chamber 14 is located between the upper drain discharge portion 11 and the lower hydraulic oil discharge portion 12. Therefore, the air pressure of the air spring 13 can prevent the water 19 flowing down through the gap 18 in the pump housing 1 from entering the hydraulic oil discharge unit 12 through the air chamber 14. This prevents the water 19 from being mixed into the hydraulic oil in the hydraulic oil discharge portion 12 even when the seal rings 7 and 8 provided above and below the air chamber 14 are damaged.
In the water injection pump 10 according to the embodiment of the present invention, the seal ring 7 that blocks the communication between the gap 18 in the pump housing 1 and the air chamber 14 is provided between the drain discharge portion 11 and the air chamber 14, and the seal ring 8 that blocks the communication between the lower internal space 4a of the pump housing 1 and the air chamber 14 is provided below the air chamber 14. Therefore, the gap 18 in the pump housing 1 and the air chamber 14 can be separated liquid-tightly (preferably air-tightly) by the upper seal ring 7 at a position lower than the drain discharge portion 11, and the lower internal space 4a of the pump housing 1 and the air chamber 14 can be separated liquid-tightly (preferably air-tightly) by the lower seal ring 8 at a position upper than the hydraulic oil discharge portion 12. As a result, the air spring 13 having an air pressure equal to or higher than a predetermined value can be easily configured in the air chamber 14.
In the above-described embodiment, the seal rings 7 and 8 are provided above and below the air chamber 14, but the present invention is not limited to this. For example, the water 19 flowing down through the gap 18 in the pump housing 1 may be stopped by the air pressure of the air spring 13 without using the seal rings 7 and 8.
In the above-described embodiment, the case where the used hydraulic oil discharged from the hydraulic oil discharge portion 12 to the hydraulic oil discharge pipe is discarded without being reused has been exemplified, but the present invention is not limited to this. For example, the used hydraulic oil discharged from the hydraulic oil discharge unit 12 to the hydraulic oil discharge pipe may be recovered to a tank or the like and reused as hydraulic oil for operating a hydraulically driven device such as the water injection pump 10.
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. Further, 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.
As described above, the water injection pump according to the present invention is useful for a water injection pump using a plunger, and is particularly suitable for the following water injection pumps: the compression spring for returning the plunger to the reference position after the water is discharged can be prevented from being corroded or damaged by the water, and the miniaturization and the low price can be achieved at the same time.
Description of the symbols
1 Pump housing
2 discharge part
2a discharge chamber
3 mounting table part
3a working oil chamber
4 support part
4a lower side inner space
5 discharge valve part
5a check valve
5b discharge port
6 plunger
6a water piston part
6b working oil piston part
6c restriction part
6d stress part
6e taper
7. 8 sealing ring
9 detection part
10 water injection pump
11 drainage discharge part
11a drainage collecting part
11b drainage way
12 working oil discharge part
12a working oil collecting part
12b working oil discharge passage
13 air spring
14 air chamber
15a air flow path
15b air inlet and outlet
16 air piping
17 water supply part
18 clearance
19 Water
F1 axial direction
F2 radial direction
P1 Lift position
Ps reference position
Claims (2)
1. A water injection pump comprising a pump housing and a plunger provided in the pump housing so as to be capable of reciprocating, wherein the plunger is moved toward an outlet side of the pump housing by a pressure of hydraulic oil, thereby pressurizing water to be discharged in the pump housing and discharging the water,
the pump housing includes:
a drain discharge portion for discharging water flowing down in a gap between an outer circumferential surface of the plunger and an inner circumferential surface of the pump housing; and
an air spring that returns the plunger to a reference position before the water to be discharged is discharged by moving the plunger after the water to be discharged is discharged toward a side of the pump housing opposite to a discharge port side,
the air spring is configured by supplying air having a pressure higher than the internal pressure of the drain discharge portion to an air chamber which is a space surrounded by the outer peripheral surface of the plunger and the inner peripheral surface of the pump housing and is located below the drain discharge portion,
the pump housing includes a working oil discharge portion for discharging working oil remaining in the pump housing below the air chamber,
the air chamber is located between the drain portion on the upper side and the working oil drain portion on the lower side.
2. The water injection pump according to claim 1, comprising:
a first seal member provided between the drain discharge portion and the air chamber, and closing a gap between an outer peripheral surface of the plunger and an inner peripheral surface of the pump housing and communication between the air chamber; and
and a second seal member provided below the air chamber and closing communication between the air chamber and a lower internal space of the pump housing located below the air chamber.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018-043425 | 2018-03-09 | ||
| JP2018043425A JP6568613B1 (en) | 2018-03-09 | 2018-03-09 | Water injection pump |
| PCT/JP2019/005959 WO2019171930A1 (en) | 2018-03-09 | 2019-02-19 | Water injection pump |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111819355A CN111819355A (en) | 2020-10-23 |
| CN111819355B true CN111819355B (en) | 2022-06-03 |
Family
ID=67766733
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980017809.6A Active CN111819355B (en) | 2018-03-09 | 2019-02-19 | Water injection pump |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP6568613B1 (en) |
| KR (1) | KR102389423B1 (en) |
| CN (1) | CN111819355B (en) |
| WO (1) | WO2019171930A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102263660B1 (en) | 2019-12-17 | 2021-06-10 | 주식회사 현대케피코 | Guide for piston of High pressure pump |
| KR102432174B1 (en) * | 2020-12-04 | 2022-08-12 | 주식회사 현대케피코 | High pressure fuel pump with fluid spring |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4018192A (en) * | 1975-07-03 | 1977-04-19 | Eft Sheldon E | Water injection system for I.C. engines |
| JP2008248839A (en) * | 2007-03-30 | 2008-10-16 | Man Diesel As | Cam driven fuel injection system for large size two cycle diesel engine |
| CN201258837Y (en) * | 2008-09-25 | 2009-06-17 | 沈焕军 | Plunger water pump structure |
| JP2010174899A (en) * | 2010-04-02 | 2010-08-12 | Man Diesel & Turbo Filial Af Man Diesel & Turbo Se Tyskland | Large-sized two-stroke diesel engine with hydraulically actuated exhaust gas valve |
| WO2013118298A1 (en) * | 2012-02-10 | 2013-08-15 | 株式会社 愛康 | Working fluid supply device and fluid supply system |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5937301A (en) * | 1982-08-21 | 1984-02-29 | Mitsubishi Electric Corp | Fuel pressure regulator of automobile |
| KR950009554B1 (en) * | 1987-10-20 | 1995-08-24 | 노바-베르케 악티엔게젤샤프트 | Liner drive with hydrauric reinforcement |
| JPH07286569A (en) * | 1994-04-19 | 1995-10-31 | A D D:Kk | Fuel injection pump |
| JP3322578B2 (en) * | 1996-10-09 | 2002-09-09 | 三菱重工業株式会社 | Two-fluid injection device |
| DK173815B1 (en) * | 1997-05-28 | 2001-11-12 | Man B & W Diesel As | Hydraulically activated fuel pump for an internal combustion engine |
| JP2000227062A (en) * | 1999-02-05 | 2000-08-15 | Aisan Ind Co Ltd | High pressure fuel pump |
| JP6546807B2 (en) | 2015-08-04 | 2019-07-17 | 三菱重工業株式会社 | Fuel injection pump, fuel injection device, internal combustion engine |
-
2018
- 2018-03-09 JP JP2018043425A patent/JP6568613B1/en active Active
-
2019
- 2019-02-19 KR KR1020207024937A patent/KR102389423B1/en active IP Right Grant
- 2019-02-19 CN CN201980017809.6A patent/CN111819355B/en active Active
- 2019-02-19 WO PCT/JP2019/005959 patent/WO2019171930A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4018192A (en) * | 1975-07-03 | 1977-04-19 | Eft Sheldon E | Water injection system for I.C. engines |
| JP2008248839A (en) * | 2007-03-30 | 2008-10-16 | Man Diesel As | Cam driven fuel injection system for large size two cycle diesel engine |
| CN201258837Y (en) * | 2008-09-25 | 2009-06-17 | 沈焕军 | Plunger water pump structure |
| JP2010174899A (en) * | 2010-04-02 | 2010-08-12 | Man Diesel & Turbo Filial Af Man Diesel & Turbo Se Tyskland | Large-sized two-stroke diesel engine with hydraulically actuated exhaust gas valve |
| WO2013118298A1 (en) * | 2012-02-10 | 2013-08-15 | 株式会社 愛康 | Working fluid supply device and fluid supply system |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2019171930A1 (en) | 2019-09-12 |
| KR102389423B1 (en) | 2022-04-21 |
| JP2019157711A (en) | 2019-09-19 |
| CN111819355A (en) | 2020-10-23 |
| JP6568613B1 (en) | 2019-08-28 |
| KR20200111792A (en) | 2020-09-29 |
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