KR20220041067A - Marine diesel engine - Google Patents

Abstract

The present invention relates to a marine diesel engine. According to the present invention, a urea water is directly sprayed into a combustion chamber without running out of a space for arranging components. The marine diesel engine (1) comprises: a cylinder (16) defining a combustion chamber (17); an exhaust valve (18) disposed on a cylinder cover (15) defining the ceiling surface of the combustion chamber (17) and opening and closing the combustion chamber (17); and a plurality of fuel spray valves (30) disposed on the cylinder cover (15). The plurality of fuel spray valves (30) are arranged to surround the exhaust valve (18) along the circumferential direction of the cylinder (16). All of the plurality of fuel spray valves (30) are configured to spray a fuel and the urea water in layers.

Description

Marine diesel engine {MARINE DIESEL ENGINE}

The technology disclosed herein relates to a marine diesel engine.

As a method for removing nitrogen oxides (NO _x ) contained in exhaust gas of a diesel engine, injecting urea water into a combustion chamber is widely known.

For example, the diesel engine disclosed in Patent Document 1 includes a fuel injection valve (fuel injector) for injecting fuel into a combustion chamber, and a combustion chamber and an exhaust passage in the vicinity of the combustion chamber to inject urea water. It has a configuration provided with one urea water injection valve (urea water injector) for

Japanese Patent Laid-Open No. 3-213614

By the way, by arranging the urea water injection valve as disclosed in Patent Document 1 in the vicinity of the fuel injection valve, it is conceivable to directly inject the urea water into the combustion chamber.

In this case, in an engine provided with a plurality of fuel injection valves such as a marine diesel engine, it is required to provide a urea water injection valve for each fuel injection valve, and therefore a plurality of urea water injection valves are required. Accordingly, there is a problem in that the space for arranging parts such as the urea water injection valve in the cylinder cover becomes insufficient.

The technology disclosed herein has been made in view of such a point, and an object thereof is to directly inject urea water into the combustion chamber without running out of space for arranging parts.

The inventors of the present application have focused on a fuel injection valve capable of layered injection of fuel and water instead of a general fuel injection valve. The inventors of the present application have found that urea water is used instead of water in such a fuel injection valve, and have completed the technique disclosed herein.

Specifically, the technology disclosed herein relates to marine diesel engines. The marine diesel engine includes a cylinder defining a combustion chamber, an exhaust valve disposed on a cylinder cover defining a ceiling surface of the combustion chamber and opening and closing the combustion chamber, and a plurality of fuel injection valves disposed on the cylinder cover, The plurality of fuel injection valves are arranged to surround the exhaust valve along the circumferential direction of the cylinder, and all of the plurality of fuel injection valves are configured to inject fuel and urea water in layers.

According to this configuration, all of the plurality of fuel injection valves are configured to inject fuel and urea water in layers. Accordingly, since there is no need to prepare a urea water injection valve in addition to the fuel injection valve, it is possible to sufficiently secure a space for arranging parts in the cylinder cover.

Further, by layered injection of fuel and urea water, the position at which the fuel is injected and the position at which the urea water is injected are close to each other, so that nitrogen oxides can be effectively removed.

Further, the marine diesel engine may include a plurality of valve members arranged on the cylinder cover and arranged along the circumferential direction, and the plurality of fuel injection valves may be respectively disposed in a space between the valve members.

According to this structure, each fuel injection valve can be arrange|positioned, without causing interference with each valve member. This is effective in properly disposing the fuel injection valve.

Further, the plurality of valve members may include a starting valve for supplying air to the combustion chamber, a safety valve for discharging pressure from the combustion chamber, and an indicator valve for detecting a combustion state of the combustion chamber.

In addition, the fuel injection valve includes an injection port for injecting fuel and urea water, the marine diesel engine includes a fuel pump for pumping fuel toward the fuel injection valve, and fuel from the fuel pump to the injection port a path, an injection system for injecting urea water to a predetermined position in the fuel path, and a control unit for controlling the injection system, wherein the fuel injection valve comprises: fuel pumped by the fuel pump; The urea water injected by the injection system may spray a layered liquid in which they are alternately arranged.

According to this structure, nitrogen oxides can be effectively removed.

As described above, according to the marine diesel engine, it is possible to directly inject urea water into the combustion chamber, without the space for arranging parts insufficient.

1 is a schematic diagram illustrating a configuration of a marine diesel engine.
Fig. 2 is a longitudinal sectional view illustrating a combustion chamber of a marine diesel engine.
3 is a schematic diagram illustrating the cylinder cover viewed from below.
4 is a schematic diagram illustrating a configuration of a fuel injection device.
5 : is a figure which sees and exemplifies the cylinder cover from above.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this indication is described based on drawing. Here, the following description is an example. 1 is a schematic diagram illustrating the configuration of a marine diesel engine (hereinafter simply referred to as "engine 1"). In addition, FIG. 2 is a longitudinal cross-sectional view illustrating the combustion chamber 17 of the engine 1, and FIG. 3 is a schematic diagram showing the cylinder cover 15 looking up from below. Here, FIG. 2 corresponds to the cross section A-A of FIG. 3 . 4 is a schematic diagram illustrating the configuration of the fuel injection device 100 of the engine 1 , and FIG. 5 is a diagram illustrating the cylinder cover 15 viewed from above.

The engine 1 is an in-line multi-cylinder diesel engine provided with a plurality of cylinders 16 . This engine 1 is configured as a two-stroke, one-cycle engine employing a single flow scavenging method, and is mounted on a large vessel such as an oil tanker, a container ship, and an automobile carrier.

An engine 1 mounted on a ship is used as a main engine for propelling the ship. That is, the output shaft of the engine 1 is connected to the propeller (not shown) of a ship via a propeller shaft (not shown). As the engine 1 is operated, its output is transmitted to the propeller so that the vessel is propelled.

In particular, the engine 1 according to the present embodiment is configured as a so-called crosshead internal combustion engine in order to realize its long stroke. That is, in this engine 1, the piston rod 22 which supports the piston 21 from below, and the connecting rod 24 connected to the crankshaft 23 are connected by the crosshead 25. As shown in FIG.

(1) Main composition

Hereinafter, the main part of the engine 1 is demonstrated.

As shown in FIG. 1 , the engine 1 includes a base plate 11 positioned below, a frame 12 positioned on the base plate 11 , and a cylinder jacket 13 positioned on the frame 12 . to provide The base plate 11 , the frame 12 , and the cylinder jacket 13 are fastened by a plurality of tie bolts and nuts extending in the vertical direction. The engine 1 also includes a cylinder 16 disposed in the cylinder jacket 13 , a piston 21 disposed in the cylinder 16 , and an output shaft rotating in association with the reciprocating motion of the piston 21 (eg, For example, a crankshaft 23) is provided.

The base plate 11 constitutes the crankcase of the engine 1 and accommodates the crankshaft 23 and the bearing 26 that rotatably supports the crankshaft 23 . The lower end of the connecting rod 24 is connected to the crankshaft 23 via the crank 27 .

The frame 12 accommodates a pair of guide plates 28 , a connecting rod 24 , and a crosshead 25 . Among these, the pair of guide plates 28 are made of a pair of plate-shaped members arranged along the piston axis direction, and are arranged at intervals in the width direction of the engine 1 (the left-right direction in the drawing in FIG. 1 ). The connecting rod 24 is disposed between the pair of guide plates 28 with the lower end thereof connected to the crankshaft 23 . The upper end of the connecting rod 24 is connected to the lower end of the piston rod 22 via the crosshead 25 .

Specifically, the crosshead 25 is disposed between a pair of guide plates 28 and slides in the vertical direction along each guide plate 28 . That is, the pair of guide plates 28 are configured to guide the sliding of the crosshead 25 . The crosshead 25 is connected to the piston rod 22 and the connecting rod 24 via the crosshead pin 29 . The crosshead pin 29 is connected to move up and down integrally with respect to the piston rod 22, while with respect to the connecting rod 24, the upper end of the connecting rod 24 is a fulcrum. connected to rotate.

The cylinder jacket 13 is formed by arranging a cylinder liner 14 as an inner cylinder. Inside the cylinder liner 14, the aforementioned piston 21 is disposed. The piston 21 reciprocates in the vertical direction along the inner wall of the cylinder liner 14 . In addition, the cylinder cover 15 is fixed to the upper portion of the cylinder liner 14 . The cylinder cover 15 constitutes the cylinder 16 together with the cylinder liner 14 .

In addition, an exhaust valve 18 operated by a valve device not shown is disposed on the cylinder cover 15 . The exhaust valve 18 partitions the combustion chamber 17 together with the cylinder 16 constituted by the cylinder liner 14 and the cylinder cover 15 , and the top surface of the piston 21 . The exhaust valve 18 opens and closes between the combustion chamber 17 and the exhaust pipe 19 . The exhaust pipe 19 has an exhaust port 19a leading to the combustion chamber 17, and the exhaust valve 18 is configured to open and close the exhaust port 19a.

In detail, as illustrated in FIG. 2 , the cylinder cover 15 (in particular, the lower surface of the cylinder cover 15 ) partitions the ceiling surface of the combustion chamber 17 . An exhaust port 19a of the exhaust pipe 19 is opened in the central portion of the cylinder cover 15 . The exhaust valve 18 is disposed in the central portion of the cylinder cover 15 , similarly to the exhaust port 19a , and can open and close the exhaust port 19a and furthermore the combustion chamber 17 .

Specifically, the exhaust valve 18 according to the present embodiment includes a shaft portion 18a extending in the axial direction of the piston, and an umbrella-shaped portion 18b disposed at the lower end portion of the shaft portion 18a, and the piston configured to reciprocate in an axial direction. The reciprocating motion of the exhaust valve 18 is achieved by a drive mechanism 18c connected to the shaft portion 18a of the exhaust valve 18 (see also FIG. 1 ). This drive mechanism 18c is a hydraulic drive mechanism.

In addition, a plurality of fuel injection valves 30 are disposed on the cylinder cover 15 that partitions the ceiling surface. As illustrated in FIG. 3 , the plurality of fuel injection valves 30 are arranged to surround the exhaust valve 18 along the circumferential direction of the cylinder 16 (see arrow B in FIG. 3 ).

In detail, three fuel injection valves 30 according to the present embodiment are arranged in each cylinder 16 at equal intervals of approximately 120° from the cylinder cover 15 with the exhaust valve 18 as the center. are placed Hereinafter, the three fuel injection valves 30 may be called 1st injection valve 30A, 2nd injection valve 30B, and 3rd injection valve 30C sequentially along the circumferential direction.

More specifically, in the cylinder cover 15 , a plurality of valve members 101 , 102 , 103 are disposed along the circumferential direction of the cylinder 16 , and each fuel injection valve 30 is a valve member 101 , respectively. , 102, 103) are arranged in the space between them. Here, the plurality of valve members 101 , 102 , 103 includes a starting valve 101 for supplying air to the combustion chamber 17 when the engine 1 is started, and a starting valve 101 for discharging pressure from the combustion chamber 17 . A safety valve (102) and an indicator valve (103) for detecting the combustion state of the combustion chamber (17) are provided. The starting valve 101 , the safety valve 102 , and the indicator valve 103 are arranged at equal intervals of approximately 120° in the cylinder cover 15 with the exhaust valve 18 as the center.

And in the present embodiment, the first injection valve 30A is disposed in the space between the indicator valve 103 and the starting valve 101 , and the second injection valve 30B is connected to the starting valve 101 and It is arranged in the space between the safety valve 102 , and the third injection valve 30C is arranged in the space between the safety valve 102 and the indicator valve 103 .

Moreover, as shown in FIG. 2, the some fuel injection valve 30 is equipped with the injection port 31 for injecting a fuel and urea water, respectively. Each injection port 31 is opened in the side surface of the front end of the fuel injection valve 30 . And, all of the some fuel injection valves 30 are comprised in the attitude|position which turned the injection port 31 into the combustion chamber 17, and are comprised so that the fuel and urea water may be layered-injected in the state alternately arranged.

In particular, the fuel injection valve 30 according to the present embodiment is arranged so that its longitudinal direction is perpendicular to the arranging direction of each of the valve members 101 , 102 , 103 (that is, the circumferential direction of the cylinder 16 ). (that is, the longitudinal direction of the fuel injection valve 30 is disposed along the radial direction of the cylinder 16).

Here, the fuel consists of diesel fuel as a fossil fuel, for example, and can generate the motive power of the engine 1 with the combustion. On the other hand, urea water consists of a so-called urea urea aqueous solution, and can remove nitrogen oxides (NO _x ) contained in exhaust gas.

Although described later in detail, the engine 1 according to the present embodiment includes a fuel pump 41 for pressurizing fuel to the fuel injection valve 30 and a first injection pump for injecting urea water into a path through which fuel is pressurized. (51) and a second infusion pump (61).

As shown in FIG. 1 , the fuel pump 41 , the first injection pump 51 , and the second injection pump 61 are disposed near the cylinder 16 , and respectively, the internal path 32 , the fuel component It is fluidly connected to the fuel injection valve 30 via the pipe 42 , the downstream injection pipe 52 , the upstream injection pipe 62 , and the like.

Among them, the fuel pump 41 is connected to the fuel injection valve 30 via a fuel path L from the fuel pump 41 to the injection port 31 , and injects fuel toward the fuel injection valve 30 . pressurize This fuel path L consists of the 1st internal path 32 and the fuel injection pipe 42 (including the branch pipe 42a mentioned later), and connects the fuel pump 41 and the injection port 31. It is configured as a path. Further, the first injection pump 51 and the second injection pump 61 are respectively connected to the fuel path L via the downstream injection pipe 52 and the upstream injection pipe 62, and this fuel path In (L), urea water is injected.

By configuring in this way, the fuel injection valve 30 converts the fuel pumped from the fuel pump 41 and the urea water injected by the first injection pump 51 and the second injection pump 61 to the fuel pump ( 41), it is possible to alternately (ie, in layers) inject into the combustion chamber 17 by the pressure feeding action.

In this way, the fuel injection valve 30 supplies fuel and urea water to the combustion chamber 17 to generate combustion in the combustion chamber 17 . By this combustion, the piston 21 reciprocates in the vertical direction. At this time, when the exhaust valve 18 operates and the combustion chamber 17 is opened, the exhaust gas generated by combustion is extruded into the exhaust pipe 19 and gas is introduced into the combustion chamber 17 from a scavenging port (not shown).

In addition, when the piston 21 reciprocates by combustion, the piston rod 22 reciprocates in the vertical direction together with the piston 21 . Accordingly, the crosshead 25 connected to the piston rod 22 reciprocates in the vertical direction. The crosshead 25 is configured to allow rotation of the connecting rod 24 , and the connecting rod 24 is rotated by using the connecting portion with the crosshead 25 as a fulcrum. Then, the crank 27 connected to the lower end of the connecting rod 24 cranks, and the crankshaft 23 rotates according to the crank motion. In this way, the crankshaft 23 converts the reciprocating motion of the piston 21 into rotational motion, and rotates the propeller of a ship together with a propeller shaft. Thereby, the ship is propelled.

(2) Configuration regarding fuel injection device

Hereinafter, the fuel injection valve 30 and various devices for supplying fuel and urea water to the fuel injection valve 30 are collectively referred to as a fuel injection device, and the reference numeral "100" is attached thereto for description. Here, an arrow indicated by a solid line in FIG. 4 indicates the flow of fuel and urea water, and an arrow indicated by a broken line indicates transmission and reception of electric signals.

As shown in FIG. 4 , the fuel injection device 100 according to the present embodiment has a plurality of (three in this embodiment) fuel injection valves 30 as main components, and a pressure-feeding system for supplying fuel by pressure. 40, and injection systems 50 and 60 for injecting urea water, a pressure feeding system 40, and a control unit 92 for controlling the injection systems 50 and 60 are provided.

Among these, the fuel injection valve 30 is provided with the injection port 31 for injecting fuel and urea water as mentioned above, and is connected with the fuel pump 41 via the fuel path L.

On the other hand, the injection systems 50 and 60 are configured to inject urea water into the predetermined positions P1 and P2 in the fuel path L. In particular, the injection systems 50 and 60 according to the present embodiment include a downstream injection system 50 for injecting urea water into a predetermined first injection position P1 in the fuel path L, and a fuel path ( In L), an upstream injection system 60 for injecting urea water into a second injection position P2 on the upstream side of the first injection position P1 is provided.

The fuel injection device 100 also includes, as other components, a urea water supply pump 71 for supplying urea water to the injection systems 50 and 60 , the pressure feeding system 40 , and the injection systems 50 , 60 . ), a pressure accumulator 81 for operating, and a detection unit 91 for inputting a detection signal to the control unit 92 .

Hereinafter, the fuel injection valve 30 , the pressure feeding system 40 , the downstream injection system 50 , the upstream injection system 60 , the urea water supply pump 71 , the pressure accumulator 81 , the detection unit 91 , and the configuration of the control unit 92 will be described sequentially.

(fuel injection valve (30))

The plurality of fuel injection valves 30 are injection valves for layered injection of fuel and urea water into the combustion chamber 17 in the cylinder 16 as described above. Each fuel injection valve 30 is arrange|positioned three each in each cylinder 16 of the engine 1, as mentioned above. Each of these plurality of fuel injection valves 30 is configured similarly. Then, below, the structure regarding the fuel injection valve 30 is demonstrated taking one (1st injection valve 30A) of these some fuel injection valves 30 as an example.

As shown in FIG. 4 , the fuel injection valve 30 is connected to the fuel pump 41 of the pressure feeding system 40 and the fuel injection pipe 42 or the like. In addition, the fuel injection valve 30 includes a first injection pump 51 and a second injection pump 61 of the injection systems 50 and 60, an upstream injection pipe 62 and a downstream injection pipe ( 52) and the like. As shown in FIG. 2 , the fuel injection valve 30 includes the fuel pumped by the fuel pump 41 , the urea water injected by the downstream injection system 50 , and the fuel pumped by the fuel pump 41 . , the layered liquid 200 arranged in the above order of the urea water injected by the upstream injection system 60 and the fuel pumped by the fuel pump 41 is injected from the injection port 31 into the combustion chamber 17 . do.

Specifically, as shown in FIG. 4 , the fuel injection valve 30 includes the injection port 31 configured as described above, two internal paths 32 and 33 leading to the injection port 31 , and two It has check valves 34a and 34b.

One internal path 32 of the two internal paths 32 and 33 is a path for mainly allowing fuel to flow, and connects the branch pipe 42a of the fuel injection pipe 42 and the injection port 31 . Hereinafter, one inner path 32 is referred to as a "first inner path 32". In the first internal path 32 , an upstream injection pipe 62 of the upstream injection system 60 (specifically, a branch pipe 62a of the upstream injection pipe 62 ) is connected to a check valve 34a ) through which it is connected. The upstream injection pipe 62 extends from the second injection pump 61 and is a pipe through which the urea water pressure-feed from the second injection pump 61 flows. Accordingly, not only fuel but also urea injected from the upstream injection pipe 62 flows through the first internal path 32 .

Here, the portion where the second internal path 33 is connected to the first internal path 32 indicates a position in the fuel path L where the urea water is injected by the downstream injection system 50 . This position is equivalent to the "first injection position P1" described above. As shown in FIG. 4 , the second injection position P2 is formed on the upstream side of the first injection position P1 in the fuel path L. As shown in FIG. In addition, the "upstream side" as used herein indicates the upstream side of the fuel flow direction. In addition, the "circulation direction of fuel" shows the direction which goes to the injection port 31 via the fuel injection pipe 42 etc. from the fuel pump 41 .

One of the check valves 34a and 34b of the two check valves 34a permits circulation of the urea water from the upstream injection system 60 to the first internal path 32, and the urea water prevent backflow. The other check valve 34b is formed in the middle portion of the second internal path 33 . The other check valve 34b permits the flow of urea water from the downstream injection system 50 to the first internal path 32 via the second internal path 33, and the urea prevent reflux of water.

(Pressure system (40))

The pressure feeding system 40 is a facility for feeding fuel by pressure to the fuel injection valve 30 . As shown in FIG. 4 , the pressure feeding system 40 includes a fuel pump 41 , a fuel injection pipe 42 , and a control valve 45 .

The fuel pump 41 is a hydraulically driven pump that pumps fuel by using the pressure of hydraulic oil. Specifically, the fuel pump 41 is connected to a fuel tank (not shown) in which fuel is stored through a pipe or the like, and is supplied with fuel from the fuel tank. The fuel pump 41 pressurizes the fuel supplied from the fuel tank to the fuel injection valve 30 through the fuel injection pipe 42 . In addition, the pressure feeding action of the fuel pump 41 also enables the fuel injection valve 30 to inject fuel and urea water in layers.

The fuel injection pipe 42 is a pipe for allowing fuel to flow between the fuel pump 41 and the fuel injection valve 30 . For example, as shown in FIG. 4 , one end of the fuel injection pipe 42 is connected to a discharge port of the fuel pump 41 . Moreover, the branch part 43 is formed in the intermediate part of the fuel injection pipe 42 . The fuel injection pipe 42 branches from this branch part 43 into a plurality of branch pipes toward the other end. Specifically, the fuel injection pipe 42 according to the present embodiment branches from the branch portion 43 into three branch pipes 42a, 42b, and 42c. Among these branch pipes 42a, 42b, and 42c, the first branch pipe 42a is connected to the first internal path 32 of one fuel injection valve 30, as shown in FIG. The fuel injection pipe 42 communicates with the fuel pump 41 with the first internal path 32 of the fuel injection valve 30 via a branch pipe 42a. Similarly, the remaining branch pipes 42b and 42c are respectively connected to the other fuel injection valves 30 .

The control valve 45 is a valve for controlling supply of hydraulic oil from the pressure accumulator 81 to the fuel pump 41 . Specifically, the control valve 45 is constituted by an electric on/off valve such as a solenoid valve, and although not shown, by opening and closing a logic valve driven by the control valve 34 , as shown in FIG. 4 . As shown, the fuel pump 41 and the pressure accumulator 81 are disposed so as to be able to communicate. The control valve 45 is in an open state during a fuel injection period (hereinafter simply referred to as an "injection period"), and supplies the hydraulic oil in the pressure accumulator 81 to the fuel pump 41 . The fuel pump 41 pressurizes fuel to the fuel injection valve 30 using the pressure of this supplied hydraulic oil. On the other hand, the control valve 45 is in a closed state in a period other than the fuel injection period, and stops supply of hydraulic oil from the pressure accumulator 81 to the fuel pump 41 . The opening/closing of the control valve 45 is controlled by the control unit 92 .

(Downstream injection system (50))

The downstream injection system 50 is, as shown in FIG. 4, the 1st injection pump 51 mentioned above, the downstream injection pipe 52, the check valve 54, and the 1st control valve 55. to provide The downstream injection system 50 is an example of the "first injection system" of this embodiment.

The first injection pump 51 is a hydraulically driven pump that injects urea water using the pressure of hydraulic oil. In detail, the first injection pump 51 receives urea water from the urea water supply pump 71 through the supply pipe 72 or the like. The first injection pump 51 pressurizes the supplied urea water. The urea water pumped by the pressure from the first injection pump 51 passes through the downstream injection pipe 52 and the second internal path 33 of the fuel injection valve 30 to the first of the fuel injection valve 30 . An inner path 32 is reached. In this way, the first injection pump 51 injects the urea water into the first injection position P1 of the fuel path L.

The downstream injection pipe 52 is a pipe for circulating the urea water injected into the fuel path L by the first injection pump 51 . For example, as shown in FIG. 4 , one end of the downstream injection pipe 52 is connected to a discharge port of the first injection pump 51 . In addition, a branching portion 53 is formed in an intermediate portion of the downstream injection pipe 52 . The downstream injection pipe 52 branches from this branch part 53 into a plurality of branch pipes toward the other end part. Specifically, the downstream injection pipe 52 according to the present embodiment branches from the branch portion 53 into three branch pipes 52a, 52b, and 52c. Among these branch pipes 52a, 52b, and 52c, the first branch pipe 52a is connected to the second internal path 33 of one fuel injection valve 30, as shown in FIG. The downstream injection pipe 52 communicates with the second internal path 33 of the fuel injection valve 30 and the first injection pump 51 via a branch pipe 52a. Similarly, the remaining branch pipes 52b and 52c are respectively connected to the different fuel injection valves 30 .

The check valve 54 is a valve for regulating the flow direction of the urea water in the downstream injection pipe 52 in one direction and preventing a reverse flow of the urea water. As shown in FIG. 4 , the check valve 54 is disposed at an intermediate portion of the downstream injection pipe 52 , for example, between the first injection pump 51 and the branching portion 53 . The check valve 54 allows the flow of urea water from the first injection pump 51 to the second internal path 33 via the branch 53 and prevents a reverse flow of the urea water. .

The first control valve 55 is a valve for controlling supply of hydraulic oil from the pressure accumulator 81 to the first injection pump 51 . Specifically, the first control valve 55 is constituted by an electric on/off valve such as a solenoid valve, and as shown in FIG. 4 , the first injection pump 51 and the pressure accumulator 81 are disposed so that communication is possible. do. The first control valve 55 is in an open state during a period in which the urea water pumped from the first injection pump 51 is injected into the fuel path L (hereinafter referred to as a "first injection period"), and the pressure accumulating unit The hydraulic oil in (81) is supplied to the 1st injection pump (51). The first injection pump 51 pressurizes and injects urea water to the first injection position P1 of the fuel path L by using the pressure of the supplied hydraulic oil. On the other hand, the first control valve 55 is closed during a period other than the first injection period by the downstream injection system 50 , and hydraulic oil is supplied from the pressure accumulator 81 to the first injection pump 51 . stop being The opening and closing of the first control valve 55 is controlled by the control unit 92 .

(Upstream injection system (60))

As shown in FIG. 4 , the upstream injection system 60 includes the above-described second injection pump 61 , the upstream injection pipe 62 , the check valve 64 , and the second control valve 65 . to provide The upstream injection system 60 is an example of the "second injection system" of this embodiment.

The second injection pump 61 is a hydraulically driven pump that injects urea water using the pressure of hydraulic oil. In detail, the second injection pump 61 receives the replacement fuel from the urea water supply pump 71 through the supply pipe 72 or the like. The second injection pump 61 pressurizes the supplied urea water. The urea water pressurized from the second injection pump 61 reaches the first internal path 32 of the fuel injection valve 30 through the upstream injection pipe 62 . In this way, the second injection pump 61 injects the urea water into the second injection position P2 of the fuel path L.

The upstream injection pipe 62 is a pipe for circulating the urea water injected into the fuel path L by the second injection pump 61 . For example, as shown in FIG. 4 , one end of the upstream injection pipe 62 is connected to a discharge port of the second injection pump 61 . In addition, a branching portion 63 is formed in the middle portion of the upstream injection pipe 62 . The upstream injection pipe 62 branches from the branch 63 toward the other end into a plurality of branch pipes. Specifically, the upstream injection pipe 62 according to the present embodiment branches from the branch portion 63 into three branch pipes 62a, 62b, and 62c. Of these branch pipes 62a, 62b, and 62c, the first branch pipe 62a is, as shown in FIG. 4, a first internal path ( 32) is connected. The upstream injection pipe 62 communicates with the first internal path 32 of the fuel injection valve 30 and the second injection pump 61 via a branch pipe 62a. Similarly, the remaining branch pipes 62b and 62c are respectively connected to the other fuel injection valves 30 .

The check valve 64 is a valve for regulating the flow direction of the urea water in the upstream injection pipe 62 in one direction and preventing a reverse flow of the urea water. As shown in FIG. 4 , the check valve 64 is disposed at an intermediate portion of the upstream injection pipe 62 , for example, between the second injection pump 61 and the branching portion 63 . The check valve 64 permits the flow of urea water from the second infusion pump 61 to the first internal path 32 via the branch 63 and prevents a reverse flow of the urea water. .

The second control valve 65 is a valve for controlling supply of hydraulic oil from the pressure accumulator 81 to the second injection pump 61 . Specifically, the second control valve 65 is constituted by an electric on/off valve such as a solenoid valve, and as shown in FIG. 4 , the second injection pump 61 and the pressure accumulator 81 are disposed so that communication is possible. do. The second control valve 65 is in an open state during a period in which the urea water pumped from the second injection pump 61 is injected into the fuel path L (hereinafter referred to as a "second injection period"), and the pressure accumulating unit The hydraulic oil in (81) is supplied to the 2nd injection pump (61). The second injection pump 61 pressurizes and injects the urea water to the second injection position P2 of the fuel path L by using the pressure of the supplied hydraulic oil. On the other hand, the second control valve 65 is closed in a period other than the second injection period by the upstream injection system 60 , and hydraulic oil is supplied from the pressure accumulator 81 to the second injection pump 61 . stop being The opening and closing of the second control valve 65 is controlled by the control unit 92 .

(Urea water supply pump (71))

The urea water supply pump 71 is a pump for supplying the urea water injected into the fuel path L to the first injection pump 51 and the second injection pump 61 . As shown in FIG. 4 , the urea water supply pump 71 is connected to the first injection pump 51 and the second injection pump 61 via a supply pipe 72 or the like so that communication is possible.

Specifically, one end of the supply pipe 72 is connected to the urea water supply pump 71 , and the other end of the supply pipe 72 is branched into two to the first injection pump 51 and the second injection pump 61 . connected In detail, the supply pipe 72 branches into the branch pipes 72a and 72b at the intermediate part. One branch pipe 72a branched from the supply pipe 72 is connected to the first injection pump 51 via a check valve 73a. The other branched pipe 72b is connected to the second injection pump 61 via a check valve 73b.

The urea water supply pump 71 according to the present embodiment is connected to a tank (not shown) that stores urea water, and removes the urea water stored in the tank through branch pipes 72a and 72b or the like. The first infusion pump 51 and the second infusion pump 61 are supplied.

The check valve 73a permits circulation of the urea water from the urea water supply pump 71 to the first injection pump 51 and prevents a reverse flow of the urea water. The check valve 73b allows the flow of urea water from the alternative fuel supply pump 71 to the second injection pump 61 and prevents a reverse flow of the urea water.

(Pressure accumulator 81)

The pressure accumulator 81 accumulates hydraulic oil for operating the pressure feeding system 40 and the injection systems 50 and 60, respectively. The pressure accumulation part 81 is a hollow structure provided with the pressure accumulation chamber which can store hydraulic oil, and is connected with the high pressure pump 82 as shown in FIG. The pressure accumulating unit 81 stores the hydraulic oil pressure-fed from the high-pressure pump 82 and pressurizes it. The pressure of the hydraulic oil in the pressure accumulator 81 is adjusted according to the discharge amount of the hydraulic oil discharged from the high pressure pump 82 to the pressure accumulator 81 . The pressure of the hydraulic oil in the pressure accumulator 81 is the fuel pump 41 of the pressure feeding system 40 , the first injection pump 51 of the downstream injection system 50 , and the upstream injection system 60 . It is shared in the second infusion pump 61 .

(detection unit 91)

The detection unit 91 detects the crank angle of the engine 1 . The detection part 91 which concerns on this embodiment detects the rotation angle (so-called "crank angle") of the crank 27 which rotates with one cycle of reciprocating motion of the piston 21. As shown in FIG. In that case, the detection part 91 detects the rotation angle from the reference state of the crank 27 as a crank angle. Here, as a reference state of the crank 27, the crank 27 state when the piston 21 is located at bottom dead center or top dead center, etc. are mentioned, for example. The detection part 91 detects the crank angle which changes with time, and transmits the electric signal which shows the detected crank angle to the control part 92 each time.

(control unit 92)

The control unit 92 includes the control valve 45 of the pressure feeding system 40 , the first control valve 55 of the downstream injection system 50 , and the second control valve 65 of the upstream injection system 60 . control the opening and closing of Thereby, the control unit 92 controls the layered injection timing by the fuel injection valve 30, the timing at which the downstream injection system 50 injects urea water, and the upstream injection system 60 injects the urea water. You can control the timing.

Here, in this embodiment, the layered injection timing by the fuel injection valve 30 means the timing of layered injection of fuel and urea water from the fuel injection valve 30 to the combustion chamber 17 .

In addition, the timing at which the downstream injection system 50 injects the urea water includes the timing at which the downstream injection system 50 starts injection of the urea water and the downstream injection system 50 ends the injection of the urea water. timing is included. Similarly, at the timing at which the upstream injection system 60 injects urea water, the upstream injection system 60 starts injection of the urea water, and the upstream injection system 60 finishes injection of the urea water. timing is included.

Specifically, the control unit 92 is constituted by a CPU, a memory, and a programmable logic controller (PLC) for executing various programs. The control unit 92 receives the electric signal from the detection unit 91, and the control valve 45 of the pressure feeding system 40 becomes an open state at the timing at which the crank angle indicated by the received electric signal becomes a predetermined rotation angle. control the opening and closing of The control unit 92 controls the timing at which the fuel pump 41 operates through the control of the control valve 45 . Thereby, the control part 92 controls the layered injection timing by the fuel injection valve 30.

In particular, the control unit 92 according to the present embodiment is configured so that, among the fuel and urea water injected into the combustion chamber 17 at the layered injection timing, both the fuel layer and the urea water layer are two or more. , to control the injection system (50, 60).

At this layered injection timing, a required amount of fuel according to the engine load among the fuel pumped to the fuel path L by the fuel pump 41 and the first injection of the fuel path L by the first injection pump 51 The urea water injected at the position P1 and the urea water injected into the second injection position P2 of the fuel path L by the second injection pump 61 are generated by the pressure feeding action of the fuel pump 41 . It is injected in layers from the injection valve 30 to the combustion chamber 17 .

As a result, the fuel injection valve 30 according to the present embodiment is, as shown in FIG. 2 , the fuel pumped by the fuel pump 41 , the urea water injected by the downstream injection system 50 , and the fuel pump The fuel pumped by pressure (41), the urea water injected by the upstream injection system (60), and the fuel pumped by the fuel pump (41) are arranged in the order described above in the combustion chamber. (17) will be sprayed within. Thereafter, the fuel path L illustrated in Figs. 2 and 4 is in a state filled with the fuel remaining without being injected.

In addition, the control part 92 controls the fuel path L which is in a state full of fuel, especially the 1st injection position P1 of the fuel path L in the period other than the above-mentioned layered injection timing of fuel and urea water. ) and the second injection position P2, the downstream injection system 50 injects the urea water and the upstream injection system 60 controls the timing of injecting the urea water so as to inject the urea water into each.

At this time, according to the load of the engine 1 (hereinafter simply referred to as "engine load"), the control unit 92 determines the timing at which the downstream injection system 50 starts injection of urea water, and the upstream injection system. (60) controls the timing of starting the injection of the urea water.

Specifically, the control unit 92 calculates a predetermined waiting time based on the engine load and determines the timing at which the downstream injection system 50 starts injection of urea water by the calculated waiting time, It is made later than the timing at which the upstream injection system 60 starts injection|pouring of urea water.

In more detail, the control unit 92 controls the ratio of the injection amount of urea water by the downstream injection system 50 to the injection amount of urea water by the upstream injection system 60 to be constant, despite the engine load. , controls the downstream injection system 50 and the upstream injection system 60 .

In addition, in the layered liquid 200 , the control unit 92 is disposed between the layer of urea water formed by the downstream injection system 50 and the layer of urea water formed by the upstream injection system 60 . The timing at which the downstream injection system 50 starts injection of urea water, the upstream The injection system 60 controls the timing of starting injection of the urea water.

(3) Specific example of fuel injection valve arrangement

5 : is a figure which sees and exemplifies the cylinder cover 15 from above. Hereinafter, the upper side of the drawing of FIG. 5 is referred to as "right", the lower side of the drawing is referred to as "left", the left side of the drawing is referred to as "before", and the right side of the drawing is referred to as "after". In addition, the up-down direction of FIGS. 1 and 2 corresponds to the direction penetrating the figure of FIG.

As described above, the three fuel injection valves 30 are arranged so as to surround the exhaust valve 18 along the circumferential direction of the cylinder 16 , and are respectively disposed between the valve members 101 , 102 , 103 . placed in the space between them. Hereinafter, the specific example of this arrangement|positioning is demonstrated using FIG.

As illustrated in FIG. 5 , in the central portion of the cylinder cover 15 , a driving mechanism 18c constituting the exhaust valve 18 and a fastening member 18d are disposed. Specifically, the fastening member 18d extends in the left-right direction, is formed in a thick plate shape having a thickness in the up-down direction, and is attached to the upper surface of the cylinder cover 15 by a pair of left and right fasteners 18F and 18A. is fixed The pair of left and right fasteners 18F and 18A are shaft-shaped members extending in the vertical direction, respectively. A driving mechanism 18c is disposed on the upper surface of the fastening member 18d. Specifically, the driving mechanism 18c is mounted on the upper surface of the central portion in the left-right direction of the fastening member 18d.

The exhaust pipe 19 described above is connected to the upper surface of the cylinder cover 15 . Specifically, the exhaust pipe 19 extends from the upper surface of the cylinder cover 15 to the right.

Further, among the three fuel injection valves 30 , the first injection valve 30A is disposed on the right side inclined rear side of the upper surface of the cylinder cover 15 , and the second injection valve 30B is disposed on the upper surface of the cylinder cover 15 . is disposed on the right side inclined front side, and the third injection valve 30C is disposed on the left side of the upper surface of the cylinder cover 15 .

And, the safety valve 102 among the plurality of valve members 101 , 102 , 103 is disposed on the left inclined front side of the upper surface of the cylinder cover 15 , and the indicator valve 103 is disposed on the upper surface of the cylinder cover 15 . It is placed on the left inclined rear.

Here, the branch pipes 42a, 52a, 62a, 42b, 52b, 62b, 42c, 52c, 62c connected to each of the three fuel injection valves 30 are bundled for each fuel injection valve 30 , and all , extending from the left to the right in FIG. 5 .

Among these, when the branch pipes 42c, 52c, 62c connected to the third injection valve 30C are called "third branch pipe 35C", this third branch pipe 35C is substantially in the left-right direction. , and its right end is connected to the third injection valve 30C.

On the other hand, if the branch pipes 42a, 52a, 62a connected to the first injection valve 30A are called "first branch pipes 35A", this first branch pipe 35A is the indicator valve 103 . It extends so as to bypass the exhaust valve 18 (specifically, the fastening member 18d and the fastener 18A of the exhaust valve 18) from the rear side while passing directly above the .

Specifically, the first branch pipe 35A extends approximately in the left-right direction, and then extends while being bent backwards inclined to the right. At this time, the first branch pipe 35A passes directly above the indicator valve 103 . After that, the first branch pipe 35A is bent again inclined forward to the right at a site near the rear end of the exhaust valve 18 (specifically, the fastener 18A of the exhaust valve 18), It is connected to the 1st injection valve 30A.

In addition, when the branch pipes 42b, 52b, 62b connected to the second injection valve 30B are called "second branch pipe 35B", this second branch pipe 35B is the safety valve 102 . It extends so as to bypass the exhaust valve 18 (specifically, the fastening member 18d and the fastener 18F of the exhaust valve 18) from the front side while passing directly above the .

Specifically, the second branch pipe 35B extends approximately in the left-right direction, and then extends while being bent forwardly inclined to the right. At this time, the second branch pipe 35B passes directly above the safety valve 102 . After that, the second branch pipe 35B is bent back inclined to the right at a site near the front end of the exhaust valve 18 (specifically, the fastener 18F of the exhaust valve 18). extended and connected to the second injection valve 30B.

Here, the height positions of the first branch pipe 35A, the second branch pipe 35B, and the third branch pipe 35C are set to be substantially the same. Specifically, the height position of a portion of the first branch pipe 35A that bypasses the exhaust valve 18 , particularly the fastener 18A from the rear side, is substantially the same as that of the fastener 18A. Similarly, a height position of a portion of the second branch pipe 35B that bypasses the exhaust valve 18 , particularly the fastener 18F from the front side, is substantially the same as that of the fastener 18F.

(4) Specific effects in fuel injection valve arrangement

As described above, all of the plurality of fuel injection valves 30 are configured to inject fuel and urea water in layers. Accordingly, since it is not necessary to prepare an injection valve for exclusive use of urea water together with the fuel injection valve 30 , it is possible to sufficiently secure a space for arranging components in the interior of the combustion chamber 17 .

In addition, as illustrated in FIG. 2 , by layered injection of fuel and urea water, the position at which the fuel is injected and the position at which the urea water is injected are close to each other, so that nitrogen oxides can be effectively removed.

In addition, as illustrated in FIG. 3 , by arranging each fuel injection valve 30 in the space between the valve members 101 , 102 , 103 , interference with each of the valve members 101 , 102 , 103 is caused. Each fuel injection valve 30 can be arranged without work. This is effective in properly disposing the fuel injection valve 30 .

(5) Other embodiments

In the above embodiment, the fuel injection device 100 provided with three fuel injection valves 30 for each cylinder 16 was exemplified, but the present disclosure is not limited thereto. For example, the number of fuel injection valves 30 may be two or more arbitrary.

In addition, in the above embodiment, the starting valve 101, the safety valve 102, and the indicator valve 103 are arranged at equal intervals of approximately 120° from the cylinder cover 15 with the exhaust valve 18 as the center. , the present disclosure is not limited to this arrangement. Depending on the dimensions of the cylinder cover 15 and the like, other arrangements may be employed.

Further, in the above embodiment, the fuel injection valve 30 is arranged so that its longitudinal direction is along the radial direction of the cylinder 16, but the present disclosure is not limited to this arrangement. For example, you may arrange|position inclined with respect to the radial direction of the cylinder 16. As shown in FIG.

1: Engine (Diesel engine for ships)
15: cylinder cover
16: cylinder
17: combustion chamber
18 : exhaust valve
30: fuel injection valve
31: nozzle
32: first internal path (fuel path)
41: fuel pump
42: fuel injection pipe (fuel path)
42a: branch pipe (fuel path)
50: downstream injection system (injection system)
60: upstream injection system (injection system)
92: control unit
101: starting valve (valve member)
102: safety valve (valve member)
103: indicator valve (valve member)
B: circumferential direction of the cylinder

Claims (4)

a cylinder partitioning the combustion chamber;
an exhaust valve disposed on a cylinder cover defining a ceiling surface of the combustion chamber and opening and closing the combustion chamber;
a plurality of fuel injection valves disposed on the cylinder cover;
The plurality of fuel injection valves are arranged to surround the exhaust valve along a circumferential direction of the cylinder,
All of the plurality of fuel injection valves are configured to inject fuel and urea water in layers
Marine diesel engine, characterized in that. The method of claim 1,
It is disposed on the cylinder cover and has a plurality of valve members arranged along the circumferential direction,
Each of the plurality of fuel injection valves is disposed in a space between the valve members.
Marine diesel engine, characterized in that. 3. The method of claim 2,
The plurality of valve members include a starting valve for supplying air to the combustion chamber, a safety valve for discharging pressure from the combustion chamber, and an indicator valve for detecting a combustion state of the combustion chamber.
Marine diesel engine, characterized in that. 4. The method according to any one of claims 1 to 3,
The fuel injection valve includes an injection port for injecting fuel and urea water,
The marine diesel engine,
a fuel pump for pumping fuel toward the fuel injection valve;
a fuel path from the fuel pump to the injection port;
an injection system for injecting urea water to a predetermined position in the fuel path;
Further comprising a control unit for controlling the injection system,
The fuel injection valve injects a layered liquid in which the fuel pumped by the fuel pump and the urea water injected by the injection system are alternately arranged.
Marine diesel engine, characterized in that.

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