JP6659484B2 - engine - Google Patents

Description

  The present invention relates to a multi-fuel engine. More specifically, the present invention relates to a configuration for preventing clogging of a liquid fuel supply pipe in an engine.

  2. Description of the Related Art Conventionally, a premixed combustion system in which a fuel gas such as a natural gas is mixed with air for combustion, and a diffusion combustion system in which a liquid fuel (fuel oil) such as heavy oil is diffused and burned are selectively used. There is known a so-called dual fuel engine that can be selectively driven. Patent Document 1 discloses an engine device that is this type of engine.

  In the engine device of Patent Document 1, a main fuel injection valve that supplies liquid fuel to a combustion chamber during combustion in a diffusion combustion system, a main fuel supply pipe for supplying liquid fuel to the main fuel injection valve, Is provided. Also, in this engine device, a pilot fuel injection valve for supplying pilot fuel to the combustion chamber for the purpose of igniting gas fuel during combustion in the premixed combustion system, and a pilot fuel for procuring pilot fuel for the pilot fuel injection valve And a supply pipe.

JP 2015-86728 A

  However, in the configuration of Patent Document 1, neither the main fuel supply pipe nor the pilot fuel supply pipe discloses a fuel filter for removing dust, dirt, and the like contained in fuel.

  Therefore, in the conventional configuration, as a layout of the fuel filter, for example, a common fuel filter is disposed in a common pipe upstream of a point branched into a main fuel supply pipe and a pilot fuel supply pipe. This is a possible solution.

  However, in that case, even if the frequency of use in the premixed combustion system and the frequency of use in the diffusion combustion system are biased, it is necessary to replace the common fuel filter with a new one after a certain frequency of use. There has been a demand for an improvement plan for reducing the frequency of replacing the fuel filter.

  The present invention has been made in view of the above circumstances, and enables maintenance of a fuel filter to be performed in accordance with the frequency of use in each of a diffusion combustion system and a premix combustion system. The task is to reduce the frequency.

Means and effects for solving the problem

  The problem to be solved by the present invention is as described above. Next, means for solving the problem and its effects will be described.

According to an aspect of the present invention, an engine having the following configuration is provided. That is, this engine is compatible with a premixed combustion system in which gaseous fuel is mixed with air before flowing into the combustion chamber, and a diffusion combustion system in which liquid fuel is injected into the combustion chamber and burned. The engine includes a main fuel injection valve, a pilot fuel injection valve, a main fuel supply path, a pilot fuel supply path, a main fuel filter, and a pilot fuel filter. The main fuel injection valve supplies liquid fuel to the combustion chamber during combustion in the diffusion combustion mode. The pilot fuel injector supplies pilot fuel to the combustion chamber for the purpose of igniting gas fuel during combustion in the premixed combustion mode. The main fuel supply path supplies liquid fuel to the main fuel injection valve. The pilot fuel supply path supplies pilot fuel to the pilot fuel injector. The main fuel filter is provided in the middle of the main fuel supply path. The pilot fuel filter is provided in the middle of the pilot fuel supply path. The main fuel filter is located above or below the pilot fuel filter. A receiving member for receiving fuel is provided below the main fuel filter and below the pilot fuel filter.

Thus, the filter for the main fuel and the filter for the pilot fuel can be maintained according to the frequency of use in each of the diffusion combustion system and the premix combustion system, and the frequency of the maintenance can be suppressed as a whole. Further, the main fuel filter and the pilot fuel filter can be arranged in a space-saving manner. Further, the fuel spilled from these filters during maintenance can be received by the common receiving member, so that the number of parts can be reduced.

  In the engine, the following configuration is preferable. That is, the engine further includes a pilot fuel supply common rail pipe that is provided at an intermediate portion of the pilot fuel supply path and supplies high-pressure pilot fuel to the pilot fuel injection valve. The filter for the pilot fuel has a higher filtration efficiency than the filter for the main fuel.

  Thus, clogging of the pilot fuel injected at a high pressure can be effectively prevented, and ignition of the gas fuel can be reliably realized.

  In the engine, it is preferable that the main fuel filter and the pilot fuel filter are arranged on the same side with respect to a virtual vertical plane including a crankshaft of the engine.

  Accordingly, maintenance of both the main fuel filter and the pilot fuel filter can be performed from one side with respect to the crankshaft of the engine, and maintenance can be easily performed.

  In the engine, it is preferable that an operation unit for starting and stopping the engine is arranged on the same side as the main fuel filter and the pilot fuel filter with respect to the virtual vertical plane. .

  Thereby, the main fuel filter and the pilot fuel filter are arranged on the same side as the operation unit which is generally arranged on the side which is easy for the operator to access, so that the maintenance is further facilitated.

FIG. 1 is an explanatory diagram schematically showing an engine and a two-system fuel supply path according to an embodiment of the present invention. Rear view of the engine. FIG. 2 is a partial rear cross-sectional view showing the configuration around the combustion chamber in detail. The front view of an engine. The top view of an engine. The right view of an engine. FIG. 2 is a schematic front perspective view showing a liquid fuel supply path. The left view of an engine. FIG. 2 is a perspective view of the engine showing a state when a part of a side cover and a heat shield cover are removed. FIG. 2 is a schematic diagram illustrating a fuel supply path for supplying fuel oil to an engine. FIG. 2 is a front perspective view of the engine showing an arrangement of a main fuel filter and a pilot fuel filter.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram schematically showing an engine 21 and two-system fuel supply paths 30 and 31 according to an embodiment of the present invention. FIG. 2 is a rear view of the engine 21. FIG. 3 is a partial rear cross-sectional view showing the configuration around the combustion chamber 110 in detail. FIG. 4 is a front view of the engine 21. FIG. 5 is a plan view of the engine 21. FIG. 6 is a right side view of the engine 21. FIG. 7 is a schematic front perspective view showing a liquid fuel supply path. FIG. 8 is a left side view of the engine 21. FIG. 9 is a perspective view of the engine 21 when a part of the side cover 43 and the heat shield cover 45 are removed.

  The engine (multi-cylinder engine) 21 of the present embodiment shown in FIG. 1 includes a premixed combustion system in which gaseous fuel is mixed with air and then flows into a combustion chamber, and a diffusion combustion in which liquid fuel is injected into a combustion chamber for combustion. This is a so-called dual fuel engine that can be used for any of these systems. The engine 21 of the present embodiment is installed via a base table on an inner bottom plate of an engine room of a ship as a drive source of a propulsion and power generation mechanism (not shown) of the ship.

  From the rear end of the engine 21, a crankshaft 24 as an engine output shaft projects rearward. A reducer (not shown) is connected to one end of the crankshaft 24 so that power can be transmitted. A propulsion shaft (not shown) of the ship is arranged so that the axis thereof coincides with the crankshaft 24 with the speed reducer interposed therebetween. At the end of the propulsion shaft, a propeller for generating a propulsion force of the ship is attached. The speed reducer has a PTO shaft, and a shaft drive generator (not shown) is connected to the PTO shaft so that power can be transmitted.

  With this configuration, the power of the engine 21 is branched and transmitted to the propulsion shaft and the shaft drive generator via the speed reducer. Thus, the propulsion force of the ship is generated, and the electric power generated by driving the shaft drive generator is supplied to the electric system in the ship.

  Next, the engine 21 will be described in detail with reference to the drawings. The engine 21 is a dual fuel engine as described above, and includes a premixed combustion system in which a fuel gas such as a natural gas is mixed with air for combustion, and a diffusion system in which a liquid fuel (fuel oil) such as heavy oil is diffused and burned. And a combustion method.

  In the following, the side connected to the speed reducer (the side on which the flywheel is arranged) is referred to as the rear side, the right side toward the front of the engine 21, the left side toward the front of the engine 21, and the engine The positional relationship between the front, rear, left and right in the configuration 21 will be described. Therefore, the front-back direction can be rephrased as a direction parallel to the axis of the crankshaft 24, and the left-right direction can be rephrased as a direction perpendicular to the axis of the crankshaft 24. However, this description does not limit the direction of the engine 21, and the engine 21 can be installed in various directions depending on the use and the like.

  As shown in FIG. 1, two systems of fuel supply paths 30 and 31 are connected to the engine 21. A gas fuel tank 32 for storing liquefied natural gas (LNG) is connected to one fuel supply path 30, and a liquid fuel tank for storing marine diesel oil (MDO) is connected to the other fuel supply path 31. 33 are connected. With this configuration, one fuel supply path 30 supplies fuel gas to the engine 21, and the other fuel supply path 31 supplies fuel oil to the engine 21.

  The fuel supply path 30 includes, in order from the upstream side, a gas fuel tank 32 for storing a liquefied gaseous fuel, a vaporizer 34 for vaporizing the liquefied fuel in the gas fuel tank 32, and a fuel from the vaporizer 34 to the engine 21. And a gas valve unit 35 for adjusting the gas supply amount.

  The engine 21 is an in-line multi-cylinder engine configured by mounting a cylinder head 26 on a cylinder block 25, as shown in FIGS. As shown in FIGS. 2 and 4, the crankshaft 24 is rotatably supported below the cylinder block 25 with the axis 24c directed in the front-rear direction.

  In the cylinder block 25, a plurality (six in the present embodiment) of cylinders are formed in a line (series) along the axis of the crankshaft 24. As shown in FIG. 3, a piston 78 is slidably accommodated in each cylinder in a vertical direction. The piston 78 is connected to the crankshaft 24 via a rod (not shown).

  As shown in FIGS. 5 and 6, a plurality (six in the present embodiment) of cylinder heads 26 are attached to the cylinder block 25 so as to cover each cylinder from above. The cylinder head 26 is provided for each cylinder, and is fixed to the cylinder block 25 using a head bolt 99. As shown in FIG. 3, in each cylinder, a combustion chamber 110 is formed in a space surrounded by the upper surface of the piston 78 and the cylinder head 26.

  As shown in FIG. 5, the plurality of head covers 40 are arranged on the cylinder head 26 in a line along the direction of the axis 24c of the crankshaft 24 (front-back direction) so as to correspond to each cylinder. As shown in FIG. 3, inside each head cover 40, a valve mechanism including a push rod, a rocker arm, and the like for operating an intake valve and an exhaust valve is housed. When the intake valve is open, intake air from the intake manifold 67 can be taken into the combustion chamber 110. When the exhaust valve is open, exhaust gas from the combustion chamber 110 can be discharged to the exhaust manifold 44.

  As shown in FIG. 3, near the left side of the head cover 40, an upper end portion of a pilot fuel injection valve 82 described later is arranged. When considering a virtual vertical plane P1 (see FIG. 7) including the axis 24c of the crankshaft 24, the pilot fuel injection valve 82 is located on one side (left side in the present embodiment) with respect to the virtual vertical plane P1. It is inserted inside the cylinder head 26 and extends obliquely downward toward the combustion chamber 110.

  In the following description, the position on one side / other side with respect to the virtual vertical plane P1 including the axis 24c of the crankshaft 24 may be expressed as one side / other side with respect to the crankshaft 24. . The virtual vertical plane P1 can be considered to be an infinitely wide plane both in the direction of the axis 24c of the crankshaft 24 and in the up-down direction. However, in FIG. Are shown only part of the virtual vertical plane P1.

  As shown in FIGS. 2, 3 and 8, on the left side of the cylinder head 26, a gas manifold 41 for distributing and supplying gas fuel to the combustion chamber 110 of each cylinder at the time of combustion in the premixed combustion system is provided. Provided. The gas manifold 41 is arranged to extend in the front-rear direction along the left side surface of the cylinder head 26. A plurality of (six in this embodiment) gas branch pipes 41a corresponding to the combustion chambers 110 of the respective cylinders are connected to the gas manifold 41, and the distal end of the gas branch pipe 41a is connected to the gas manifold 41 as shown in FIG. , A gas injector 98 for injecting gas fuel is provided. The distal end of the gas injector 98 faces an intake branch pipe 67a formed inside the cylinder head 26 corresponding to the cylinder. By injecting gas fuel from the gas injector 98, gas fuel can be supplied to the intake branch pipe 67a of the intake manifold 67.

  As shown in FIGS. 3, 7 and 9, on the right side of the cylinder block 25, a liquid fuel supply rail for distributing and supplying the liquid fuel to the combustion chamber 110 of each cylinder during the combustion by the diffusion combustion method. A pipe 42 is provided. The liquid fuel supply rail pipe 42 is arranged to extend in the front-rear direction along the right side surface of the cylinder block 25. The liquid fuel supplied to the liquid fuel supply rail pipe 42 is distributed and supplied to a fuel injection pump 89 provided for each cylinder. As shown in FIG. 3, a main fuel injection valve 79 for injecting the liquid fuel supplied from the fuel injection pump 89 is arranged in each cylinder. The main fuel injection valve 79 is disposed so as to be vertically inserted into the cylinder head 26 from above, the upper end thereof is disposed inside the head cover 40, and the lower end faces the combustion chamber 110 of the cylinder. The fuel injection pump 89 and the main fuel injection valve 79 are connected via a liquid fuel supply passage 106 formed in the cylinder head 26.

  At a position near the lower part of the liquid fuel supply rail pipe 42, a liquid fuel return collecting pipe 48 for collecting excess fuel returned from each fuel injection pump 89 is provided. The liquid fuel return collecting pipe 48 is arranged in parallel with the liquid fuel supply rail pipe 42, and is connected to the fuel injection pump 89. A liquid return pipe 115 for returning the liquid fuel to the liquid fuel tank 33 is connected to an end of the liquid fuel return collecting pipe 48.

  As shown in FIGS. 3, 7, and 9, the right side of the cylinder block 25 and above the liquid fuel supply rail pipe 42 is provided for the purpose of igniting gas fuel during combustion in the premixed combustion system. A pilot fuel supply rail pipe (pilot fuel supply common rail pipe) 47 for distributing and supplying pilot fuel to the combustion chamber 110 of each cylinder is provided. The pilot fuel supply rail pipe 47 is arranged to extend in the front-rear direction along the right side surface of the cylinder block 25. As shown in FIGS. 3 and 7, a pilot fuel injection valve 82 for injecting the liquid fuel (pilot fuel) supplied from the pilot fuel supply rail pipe 47 is arranged in each cylinder. The pilot fuel injection valve 82 is disposed so as to be obliquely inserted into the cylinder head 26 from above, the upper end thereof is disposed immediately to the left of the head cover 40, and the lower end thereof faces the combustion chamber 110 of the cylinder. As shown in FIG. 7, a pilot fuel branch pipe 109 is provided so as to branch off from the pilot fuel supply rail pipe 47 corresponding to each cylinder. The pilot fuel branch pipe 109 is arranged so as to pass between the head covers 40 arranged side by side, and is connected to the upper end of the pilot fuel injection valve 82. The pilot fuel branch pipe 109 is covered with a branch pipe cover 105 for preventing scattering of leaked fuel.

  As shown in FIGS. 3, 7 and 9, a step is formed in the upper part of the right side of the engine 21 composed of the cylinder block 25 and the cylinder head 26, and a pilot fuel supply The rail pipe 47, the liquid fuel supply rail pipe 42, and the fuel injection pump 89 are arranged. A side cover 43 is attached to the cylinder block 25 and the cylinder head 26 so as to cover the step. The pilot fuel supply rail pipe 47, the liquid fuel supply rail pipe 42, and the fuel injection pump 89 are covered with a side cover 43. FIG. 9 illustrates a state where a part of the side cover 43 is removed.

  As shown in FIGS. 2, 3, and 9, exhaust gas generated by combustion in the combustion chamber 110 of each cylinder is collected at a position above and to the left of the cylinder head 26 and above the gas manifold 41. An exhaust manifold 44 for exhausting outside is arranged in parallel with the gas manifold 41. The outer periphery of the exhaust manifold 44 is covered with a heat shield cover 45 (however, the heat shield cover 45 is removed in FIG. 9). As shown in FIG. 3, the exhaust manifold 44 is connected to exhaust branch pipes 44a corresponding to each cylinder. The exhaust branch pipe 44a communicates with the combustion chamber 110 of each cylinder.

  An intake manifold 67 for distributing and supplying air (intake) from the outside to the combustion chambers 110 of the respective cylinders is disposed parallel to the gas manifold 41 near the left side inside the cylinder block 25. As shown in FIG. 3, six intake branch pipes 67 a are formed inside the cylinder head 26 so as to branch off from the intake manifold 67, and each of the intake branch pipes 67 a communicates with the combustion chamber 110.

  With this configuration, during combustion by the diffusion combustion method, air supplied from the intake manifold 67 to each cylinder is compressed from the main fuel injection valve 79 into the combustion chamber 110 at an appropriate timing when the air is compressed by the slide of the piston 78. An amount of liquid fuel is injected. By injecting the liquid fuel into the combustion chamber 110, the piston 78 reciprocates in the cylinder by the propulsion force obtained from the explosion generated in the combustion chamber 110, and the reciprocation of the piston 78 causes the reciprocation of the crankshaft 24 via the rod. Power is obtained by conversion into rotational motion.

  On the other hand, at the time of combustion in the premixed combustion system, the gas fuel from the gas manifold 41 is injected from the gas injector 98 into the intake branch pipe 67a, so that the air supplied from the intake manifold 67 and the gas fuel are mixed. Is done. A small amount of pilot fuel is injected into the combustion chamber 110 from the pilot fuel injection valve 82 at an appropriate timing when the mixture of air and gas fuel introduced into the cylinder is compressed by the slide of the piston 78, so that the gas fuel Is ignited. The piston 78 reciprocates in the cylinder by the propulsive force obtained by the explosion in the combustion chamber 110, and the reciprocating motion of the piston 78 is converted into the rotational motion of the crankshaft 24 via a rod, thereby obtaining power.

  Regardless of whether the combustion is performed by the diffusion combustion method or the premix combustion method, the exhaust gas generated by the combustion is pushed out of the cylinder by the movement of the piston 78, collected in the exhaust manifold 44, and then discharged to the outside. You.

  As shown in FIG. 4, a cooling water pump 53, a lubricating oil pump 55, and a high-pressure fuel pump 56 are provided on the front end surface (front) of the engine 21 so as to surround the front end portion of the crankshaft 24. I have. The high-pressure fuel pump 56 is disposed on the right side of the crankshaft 24. An unillustrated rotation transmission mechanism for transmitting rotation power of the crankshaft 24 is provided at a front end portion of the engine 21. As a result, the rotational power from the crankshaft 24 is transmitted via the rotation transmission mechanism, so that the cooling water pump 53, the lubricating oil pump 55, and the fuel high-pressure pump 56 provided on the outer peripheral side of the crankshaft 24 are driven. Each is driven.

  As shown in FIG. 8, a lubricating oil cooler 58 and a lubricating oil strainer 59 are attached to the left side surface of the cylinder block 25. The lubricating oil supplied from the lubricating oil pump 55 is cooled by a lubricating oil cooler 58, purified by a lubricating oil strainer 59, and supplied to each part of the engine 21.

  The cooling water sent from the cooling water pump 53 shown in FIG. 4 cools each cylinder of the engine 21 and is then collected in a cooling water pipe 46 on the cylinder head shown in FIG.

  The intercooler 51 is arranged along the front end surface of the engine 21 and cools the air compressed by the compressor of the supercharger 49. As shown in FIG. 8, the cylinder block left cooling water pipe 60 extends rearward along the gas manifold 41 from the front of the cylinder block 25 to a position between the lubricating oil cooler 58 and the lubricating oil strainer 59. And supplies cooling water to the lubricating oil cooler 58.

  As shown in FIGS. 5 and 9, the cooling water pipe 46 above the cylinder head is provided at a position between the plurality of head covers 40, each of which is disposed above the cylinder head 26, and the exhaust manifold 44. 44 are arranged in parallel. The cylinder head upper cooling water pipe 46 is connected to a cooling water branch pipe provided for each cylinder, and through this cooling water branch pipe, a cooling water path of each cylinder (a cooling water path formed in the cylinder head 26). Connected.

  The fuel high-pressure pump 56 shown in FIG. 4 is driven to rotate to increase the pressure of the fuel oil (liquid fuel) supplied from the liquid fuel tank 33 of FIG. 1 via the fuel feed pump 166, and the pressure is increased as shown in FIG. It is sent to the pilot fuel supply rail pipe 47 via the pilot fuel supply main pipe 107 shown. A pilot fuel filter 141 for filtering fuel oil is provided in the middle of the fuel path from the liquid fuel tank 33 to the high-pressure fuel pump 56.

  When the fuel feed pump 165 shown in FIG. 1 is driven by electric power, the fuel feed pump 165 sucks the fuel oil from the liquid fuel tank 33 and passes through the liquid fuel supply main pipe 108 shown in FIG. And sent to the liquid fuel supply rail pipe 42. In the middle of the fuel oil supply path from the liquid fuel tank 33 to the liquid fuel supply rail pipe 42, a main fuel filter 131 for filtering the fuel oil is provided.

  As shown in FIG. 7, the pilot fuel supply main pipe 107, the liquid fuel supply main pipe 108, and the fuel return pipe 115 are disposed immediately in front of the cylinder block 25 along the right side surface of the cylinder block 25. The pilot fuel supply main pipe 107, the liquid fuel supply main pipe 108, and the fuel return pipe 115 are connected to the cylinder block 25 via a plurality of clamp members 111 provided to protrude rightward from the front end surface of the cylinder block 25. It is arranged so as to extend vertically along the right side surface.

  A machine-side operation control device 71 that controls the start and stop of the engine 21 via a stay is provided on the right side in front of the cylinder head 26, more specifically, on the right side surface of the intercooler 51. (See FIGS. 6 and 9). The machine-side operation control device 71 is provided with an operation unit such as a switch for receiving start / stop of the engine 21 by an operator, and a display for displaying an operation state of the engine 21. When the operator operates the machine-side operation control device 71, the engine 21 can be driven by either the premixed combustion system or the diffusion combustion system.

  Next, the configuration of the main fuel filter 131, the pilot fuel filter 141, and the surroundings will be described more specifically with reference to FIGS. FIG. 10 is a schematic diagram illustrating a fuel supply path 31 that supplies fuel oil to the engine 21. FIG. 11 is a front perspective view of the engine 21 showing the arrangement of the main fuel filter 131 and the pilot fuel filter 141.

  As shown in FIG. 10, in the present embodiment, the fuel supply path 31 for supplying the fuel oil includes a main supply path 31 a to which the main fuel injection valve 79 is to be supplied and a pilot fuel injection valve 82 to be supplied. And a pilot supply path 31b.

  In the main supply path 31a, the fuel oil in the liquid fuel tank 33 is sucked by a main fuel pump 161 installed in the engine 21 via an air separator 163 for bleeding air (the main fuel pump 161 is 1 to 9 are not shown). The fuel oil discharged from the main fuel pump 161 is supplied to the main fuel injection valve 79 via the main fuel supply path 130. The main fuel supply path 130 includes the liquid fuel supply main pipe 108, the liquid fuel supply rail pipe 42, and the liquid fuel supply path 106 described above. As shown in FIG. 10, the excess fuel oil returned from the fuel injection pump 89 is returned to the air separator 163 via the liquid fuel return collecting pipe 48 and the fuel return pipe 115. Between the fuel return pipe 115 and the air separator 163, a pressure holding valve 162 for holding the pressure of the returned fuel is provided.

  The main fuel filter 131 is provided in the middle of the main fuel supply path 130 to remove foreign substances contained in the liquid fuel. Specifically, the main fuel filter 131 filters the liquid fuel before being supplied to the main fuel injection valve 79, and captures dirt, dirt, and the like included in the liquid fuel by the switch-cleaning filter. As shown in FIGS. 10 and 11, the main fuel filters 131 are provided in pairs so that one can be used while the other is under maintenance. Thus, the main fuel filter 131 can be used continuously while the engine 21 is operating.

  As shown in FIG. 10, a pilot fuel tank 171 for storing fuel oil used especially as pilot fuel is provided separately from the liquid fuel tank 33 in the pilot supply path 31b. The pilot fuel tank 171 and the liquid fuel tank 33 are connected by an appropriate pipe. An electromagnetic valve 172 is installed in the pipe. By opening and closing the electromagnetic valve 172, fuel oil is supplied from the liquid fuel tank 33 to the pilot fuel tank 171 as necessary, and the fuel oil in the pilot fuel tank 171 is supplied. Is maintained above a certain amount.

  A pilot fuel supply pump 173 is arranged downstream of the pilot fuel tank 171. The pilot fuel supply pump 173 is driven by an electric motor (not shown) to suck the fuel oil in the pilot fuel tank 171 and discharge the fuel oil to the automatic backwash filter 174. Part of the fuel oil from which foreign matter has been removed by the automatic backwashing filter 174 is supplied to the pilot fuel injection valve 82 via the pilot fuel supply path 140. The fuel oil not supplied to the pilot fuel supply path 140 is returned to the pilot fuel tank 171. The pilot fuel supply path 140 includes the pilot fuel supply main pipe 107, the pilot fuel supply rail pipe 47, and the pilot fuel branch pipe 109 described above. Further, the fuel high-pressure pump 56 described above is disposed in the middle of the pilot fuel supply path 140.

  Each of the pilot fuel supply main pipe 107, the pilot fuel supply rail pipe 47, and the pilot fuel branch pipe 109 has a double pipe structure, and supplies fuel oil from the fuel high pressure pump 56 to the pilot fuel injection valve 82. At the same time, the fuel oil leaked from the pilot fuel injection valve 82 can be returned to the high-pressure fuel pump 56. The fuel oil returned from the pilot fuel injection valve 82 to the high-pressure fuel pump 56 and the excess fuel oil in the high-pressure fuel pump 56 are returned to the pilot fuel tank 171 via an appropriate pipe.

  The pilot fuel filter 141 is provided in the middle of the pilot fuel supply path 140 in order to remove foreign substances contained in the liquid fuel supplied as the pilot fuel. Specifically, the pilot fuel filter 141 filters the liquid fuel before being supplied to the pilot fuel injection valve 82, and captures dust and dirt contained in the liquid fuel by a replaceable paper filter. The pilot fuel filters 141 are provided in pairs so that one can be used when one is under maintenance. This allows the pilot fuel filter 141 to be used continuously while the engine 21 is operating.

  As the paper filter of the pilot fuel filter 141, a filter having a higher filtration efficiency than the switching cleaning type filter of the main fuel filter 131 is used. In other words, the fineness of the paper filter of the pilot fuel filter 141 is set finer than that of the main fuel filter 131.

  The fuel oil to be supplied to the pilot fuel injection valve 82 in the pilot supply path 31b is a loop-shaped path including a pilot fuel tank 171, a pilot fuel supply pump 173, an automatic backwash filter 174, and a pressure holding valve 164. Further, a loop-shaped path including the pilot fuel filter 141 and the fuel high-pressure pump 56 is circulated, and this path is substantially the same as the path of the fuel oil to be supplied to the main fuel injection valve 79 in the main supply path 31a. Independent. Therefore, the filter performance for the main fuel filter 131 and the filter performance for the pilot fuel 141 can be independently exhibited while using the same liquid fuel tank 33 as the base. Further, the pilot fuel oil passes through the automatic backwashing filter 174 and the pilot fuel filter 141 which are fine in number, as it circulates through the loop-shaped path. Therefore, extremely good cleanliness of the pilot fuel oil can be realized.

  As shown in FIG. 11, the pilot fuel filter 141 is disposed in front of the front end face of the engine 21 so as to project slightly rightward. The main fuel filter 131 is arranged below the pilot fuel filter 141. Specifically, a part of the main fuel filter 131 and a part of the pilot fuel filter 141 are arranged so as to overlap in plan view.

  As shown in FIG. 4 and FIG. 11, below the main fuel filter 131 and below the pilot fuel filter 141, a receiving member 150 for receiving the liquid fuel that spills during maintenance of these filters is arranged. You. Specifically, the receiving member 150 is arranged so as to cover an area immediately below the main fuel filter 131 and an area immediately below the pilot fuel filter 141 in a plan view. The receiving member 150 has a tray-like shape with an open top, and has a hole formed at the bottom. This hole is connected to one end of the drain pipe 151. The other end of the drain pipe 151 is connected to a tank (not shown) for storing drain oil.

  As described above, in the engine 21, the main fuel filter 131 and the pilot fuel filter 141 are separately provided. Therefore, the element of the main fuel filter 131 can be cleaned or the cartridge of the pilot fuel filter 141 can be replaced with a new one according to the frequency of use in each of the diffusion combustion method and the premix combustion method. . Therefore, the frequency of maintenance of the (fuel) filter as a whole can be suppressed.

  As described above, a paper filter having higher filtration efficiency than the main fuel filter 131 is used as the pilot fuel filter 141. The pilot fuel is supplied to a pilot fuel supply rail pipe (common rail pipe) 47, supplied to the pilot fuel injection valve 82 in a high pressure state, and injected into the combustion chamber 110 in a small amount. You will have to go through a small pipe. Therefore, conventionally, there is a problem that the pipe for supplying the pilot fuel is particularly likely to be clogged as compared with the pipe for supplying the main fuel. In this regard, in the present embodiment, a paper filter having a higher filtration efficiency than the filter of the main fuel filter 131 is used as the filter of the pilot fuel filter 141, so that clogging of the pilot fuel is effectively prevented. As a result, the ignition of the gas fuel can be realized steadily.

  Although a filter having a higher filtration efficiency is generally more expensive, in the present embodiment, a pilot fuel filter 141 having a higher filtration efficiency is provided in a pilot supply path 31b which is a path substantially independent of the main supply path 31a. is set up. Therefore, the fuel oil in the main supply path 31a can be prevented from flowing into the pilot fuel filter 141, so that the expensive filter is less likely to be clogged, and the cost for maintenance can be suppressed.

  As shown in FIG. 4, both the main fuel filter 131 and the pilot fuel filter 141 are on one side (specifically, a virtual vertical plane P1 including the axis 24c of the crankshaft 24 of the engine 21). The right side (the same side as the machine side operation control device 71). As described above, since both the main fuel filter 131 and the pilot fuel filter 141 are arranged at positions that are easily accessible from the right side of the engine 21, maintenance of the filters is easy. In particular, it can be said that the right side of the engine 21 is the side on which the machine-side operation control device 71 is conventionally disposed, and is the side originally configured to be easily accessible by the operator.

  The pilot fuel filter 141 and the main fuel filter 131 are vertically arranged, and the receiving member 150 is arranged so as to cover a region below these filters. Therefore, the fuel spilled from the pilot fuel filter 141 or the main fuel filter 131 at the time of maintenance can be received by the common receiving member 150, and the drain oil can be collected with a small number of parts. In addition, the pilot fuel filter 141, the main fuel filter 131, and the receiving member 150 can be rationally arranged in a small space.

  As described above, the engine 21 according to the present embodiment includes a premixed combustion method in which gaseous fuel is mixed with air and then flows into the combustion chamber 110, and a diffusion method in which liquid fuel is injected into the combustion chamber 110 and burns. And combustion method. The engine 21 includes a main fuel injection valve 79, a pilot fuel injection valve 82, a main fuel supply path 130, a pilot fuel supply path 140, a main fuel filter 131, and a pilot fuel filter 141. Prepare. The main fuel injection valve 79 supplies the liquid fuel to the combustion chamber 110 at the time of combustion by the diffusion combustion method. The pilot fuel injection valve 82 supplies pilot fuel to the combustion chamber 110 for the purpose of igniting gas fuel during combustion in the premix combustion mode. The main fuel supply path 130 supplies liquid fuel to the main fuel injection valve 79. The pilot fuel supply path 140 supplies pilot fuel to the pilot fuel injection valve 82. The main fuel filter 131 is provided in the middle of the main fuel supply path 130. The pilot fuel filter 141 is provided in the middle of the pilot fuel supply path 140.

  Accordingly, it is possible to clean the element of the main fuel filter 131 or replace the cartridge of the pilot fuel filter 141 with a new one according to the frequency of use in each of the diffusion combustion system and the premix combustion system. The frequency of maintenance of these filters can be suppressed.

  Further, the engine 21 of the present embodiment is provided in the middle of the pilot fuel supply path 140 and supplies the pilot fuel to the pilot fuel injection valve 82 at a higher pressure than the liquid fuel supplied to the main fuel injection valve 79. And a rail pipe 47 for supplying pilot fuel. The filtering efficiency of the pilot fuel filter 141 is higher than that of the main fuel filter 131.

  Thus, clogging of the pilot fuel injected at a high pressure can be effectively prevented, and ignition of the gas fuel can be reliably realized.

  In the engine 21 of the present embodiment, the main fuel filter 131 and the pilot fuel filter 141 are on the same side (the right side in the present embodiment) with respect to the virtual vertical plane P1 including the crankshaft 24 of the engine 21. Be placed.

  Accordingly, maintenance of both the main fuel filter 131 and the pilot fuel filter 141 can be performed from one side with respect to the crankshaft 24 of the engine 21, and maintenance can be easily performed.

  In the engine 21 of the present embodiment, a machine-side operation for starting and stopping the engine 21 is provided on the same side as the main fuel filter 131 and the pilot fuel filter 141 with respect to the virtual vertical plane P1. The control device 71 is arranged.

  Accordingly, the main fuel filter 131 and the pilot fuel filter 141 can be arranged on the same side as the machine side operation control device 71 which is generally arranged on the side which is easy for the operator to access, so that maintenance can be further improved. Easier to do.

  In the engine 21 of the present embodiment, the main fuel filter 131 is disposed below the pilot fuel filter 141. A receiving member 150 for receiving fuel is provided below the pilot fuel filter 141 and below the main fuel filter 131.

  Accordingly, the main fuel filter 131 and the pilot fuel filter 141 can be arranged in a space-saving manner, and the fuel spilled from these filters can be received by the common receiving member 150 during maintenance, so that the number of parts can be reduced. Can be reduced.

  Although the preferred embodiment of the present invention has been described above, the above configuration can be changed as follows, for example.

  In the above embodiment, the engine 21 is used as a drive source of a propulsion and power generation mechanism of a ship, but is not limited to this, and may be a drive source used for other purposes.

  In the above embodiment, the main fuel filter 131 and the pilot fuel filter 141 are arranged on the right side with respect to the crankshaft 24 of the engine 21. However, the present invention is not limited to this. Alternatively, it may be arranged intensively on the left side with respect to the crankshaft 24 of the engine 21. Alternatively, it may be arranged intensively above the crankshaft 24 of the engine 21.

  In the above embodiment, the main fuel filter 131 is provided below the pilot fuel filter 141. However, the upper and lower positional relations of these filters may be reversed.

  The fuel feed pump 165 for pumping the liquid fuel (fuel oil) in the main fuel supply path 130 is disposed on the downstream side of the main fuel filter 131, but on the upstream side of the main fuel filter 131. , Or any of them.

  In the above embodiment, the high-pressure fuel pump 56 is arranged downstream of the pilot fuel filter 141. However, the present invention is not limited to this. The high-pressure fuel pump 56 is arranged upstream of the pilot fuel filter 141. It may be arranged.

  In the above embodiment, the fuel oil spilled from the main fuel filter 131 or the pilot fuel filter 141 at the time of maintenance, which is received by the receiving member 150, is stored in the tank (not shown) via the drain pipe 151. And treated as drainage. However, the present invention is not limited to this, and the other end of the drain pipe 151 may be connected to the liquid fuel tank 33, and the fuel oil spilled to the receiving member 150 during maintenance may be returned to the liquid fuel tank 33.

21 engine 24 crankshaft 79 main fuel injection valve 82 pilot fuel injection valve 110 combustion chamber 130 main fuel supply path 131 main fuel filter 140 pilot fuel supply path 141 pilot fuel filter 150 receiving member

Claims (4)

An engine capable of supporting a premixed combustion system in which gaseous fuel is mixed with air and then flowing into a combustion chamber, and a diffusion combustion system in which liquid fuel is injected into the combustion chamber and burned,
A main fuel injection valve that supplies liquid fuel to the combustion chamber during combustion in the diffusion combustion mode;
A pilot fuel injection valve that supplies pilot fuel to the combustion chamber for the purpose of igniting gas fuel during combustion in the premixed combustion system,
A main fuel supply path for supplying liquid fuel to the main fuel injection valve,
A pilot fuel supply path for supplying pilot fuel to the pilot fuel injection valve,
A main fuel filter provided in the middle of the main fuel supply path,
A pilot fuel filter provided in the middle of the pilot fuel supply path,
Equipped with a,
The main fuel filter is disposed above or below the pilot fuel filter,
An engine, wherein a receiving member for receiving fuel is provided below the main fuel filter and below the pilot fuel filter . The engine according to claim 1, wherein
A pilot fuel supply common rail pipe is provided at an intermediate portion of the pilot fuel supply path and supplies pilot fuel to the pilot fuel injection valve at a higher pressure than liquid fuel supplied to the main fuel injection valve. ,
The engine according to claim 1, wherein the pilot fuel filter has a higher filtration efficiency than the main fuel filter. The engine according to claim 1 or 2,
The engine, wherein the main fuel filter and the pilot fuel filter are arranged on the same side with respect to a virtual vertical plane including a crankshaft of the engine. The engine according to claim 3, wherein
An engine, wherein an operation unit for starting and stopping the engine is arranged on the same side of the virtual vertical plane as the main fuel filter and the pilot fuel filter.

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