Engine and power generation set

Abstract

An engine that combusts a gas fuel containing hydrogen comprises: a cylinder block including a crank case inside of which a plurality of combustion chambers are formed and in which a crankshaft provided below the combustion chambers is accommodated; a rocker cover defining an upper space that covers an upper part of a cylinder head provided above the cylinder block and communicates with the crank chamber of the crank case; a breather line inside of which a blow-by gas flow passage through which blow-by gas discharged from the upper space flows is formed; and an exhaust line inside of which an exhaust flow passage through which exhaust gas discharged from the combustion chambers flows is formed. The breather line includes a plurality of breather branch sections which communicate with the upper space and into which blow-by gas flows, a breather collection section connected with each of the plurality of breather branch sections, and a breather flow section extending to one side in the axial direction of the crankshaft from a breather merging end which is one end connected to the breather collection section. The exhaust line includes a plurality of exhaust branch sections which communicate with the combustion chambers and into which the exhaust gas flows, an exhaust collection section connected with each of the plurality of exhaust branch sections, and an exhaust flow section extending to the other side in the axial direction from an exhaust confluence end which is one end connected to the exhaust collection section.

Description

Engines and generator sets

[0001] This disclosure relates to an engine that burns gaseous fuel containing hydrogen, and a power generation set including the engine. This application claims priority to Japanese Patent Application No. 2024-089116, filed with the Japan Patent Office on May 31, 2024, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses an engine (four-stroke engine) that uses gas fuel containing hydrogen and discharges blow-by gas leaking into the crankcase from an exhaust gas discharge passage (so-called breather piping) connected to the top of the rocker cover.

[0003] Japanese Patent Application Laid-Open No. 2023-124990

[0004] Hydrogen is easier to ignite than methane or propane. For this reason, engines must be designed with hydrogen's characteristics in mind. When the engine is running, the exhaust pipe becomes hot due to the exhaust gases emitted from the combustion chamber. If the breather pipe is located close to the exhaust pipe, there is a risk of unintended malfunctions occurring due to hydrogen ignition in the breather pipe. Furthermore, if the breather pipe is located close to the exhaust pipe, hydrogen leaking from the breather pipe may reach the hot exhaust pipe and unintendedly ignite.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide an engine that can prevent unintended malfunctions caused by ignition of gas fuel containing hydrogen, and a power generation set equipped with this engine.

[0006] In order to achieve the above object, the engine according to the present disclosure is an engine that burns gas fuel containing hydrogen, and includes a cylinder block having a plurality of combustion chambers formed therein and including a crankcase that houses a crankshaft disposed below the combustion chambers, a rocker cover that defines an upper space that covers an upper portion of a cylinder head disposed above the cylinder block and communicates with a crank chamber of the crankcase, a breather line formed therein with a blow-by gas flow path through which blow-by gas discharged from the upper space flows, and an exhaust flow path formed therein through which exhaust gas discharged from the combustion chamber flows. and an exhaust line connected to the upper space, wherein the breather line includes a plurality of breather branches that are connected to the upper space and into which the blow-by gas flows, a breather collection section connected to each of the plurality of breather branches, and a breather circulation section that extends from a breather junction end that is one end connected to the breather collection section to one side in the axial direction of the crankshaft, and the exhaust line includes a plurality of exhaust branches that are connected to the combustion chamber and into which the exhaust gas flows, an exhaust collection section connected to each of the plurality of exhaust branches, and an exhaust circulation section that extends from an exhaust junction end that is one end connected to the exhaust collection section to the other side in the axial direction.

[0007] In order to achieve the above-mentioned object, the power generating set of the present disclosure comprises the above-mentioned engine, which drives a generator by burning the gas fuel, and an enclosure in which a power chamber is formed to house the generator and the engine, and the enclosure has an intake port for taking in air into the power chamber formed on one side of the breather junction end in the axial direction, and an exhaust port for discharging the air taken into the power chamber from the power chamber formed on the other side of the exhaust junction end in the axial direction.

[0008] The engine and power generation set of the present disclosure can prevent unintended malfunctions caused by ignition of hydrogen.

[0009] The present invention relates to a generator engine, a power generating set, a generator set including a generator engine, a generator set for generating electricity, a generator set for generating power, a generator set for generating electricity ...

[0010] An engine and a power generating set according to an embodiment of the present disclosure will be described below with reference to the drawings. The embodiment shows one aspect of the present disclosure, and is not intended to limit the present disclosure. Any modification can be made within the scope of the technical concept of the present disclosure.

[0011] <Engine> (Configuration) An engine according to the present disclosure burns gaseous fuel containing hydrogen. The engine may be a V-engine in which two cylinders are arranged in a V-shape, or an in-line engine in which multiple cylinders are arranged in series. In some embodiments, the engine is a 12-cylinder multi-cylinder V-engine. This disclosure will be described using as an example a power generation engine that burns gaseous fuel to drive a generator. The engine according to the present disclosure can be applied to applications other than power generation engines, and may be applied, for example, to a compressor drive engine for driving a compressor.

[0012] In this disclosure, "hydrogen-containing gas fuel" includes those containing hydrogen and a fuel other than hydrogen (mixed combustion) and those containing only hydrogen (monocarbon combustion).Furthermore, those containing hydrogen and a fuel other than hydrogen can be classified into fuels in which hydrogen is the main component (volume ratio of hydrogen is 50% or more) and fuels in which a fuel other than hydrogen is the main component (volume ratio of hydrogen is less than 50%).Hereinafter, "hydrogen-containing gas fuel" will be referred to as "gas fuel F".

[0013] FIG. 1 is a diagram showing a schematic configuration of a generator engine 1 according to one embodiment, as viewed from above. FIG. 2 is a diagram illustrating the flow of blow-by gas Gb in the generator engine 1 according to one embodiment. As shown in FIG. 1 , the generator engine 1 includes a cylinder block 2, a rocker cover 4, a breather line 6, and an exhaust line 8. In one embodiment, as shown in FIG. 2 , the generator engine 1 further includes a cylinder head 10 provided above the cylinder block 2 and an intake line 11 configured to allow combustion air A to flow toward a combustion chamber 3. The cylinder head 10 covers the combustion chamber 3 formed inside the cylinder block 2 from above. The cylinder head 10 is formed with an intake port 12 communicating with the combustion chamber 3 and for supplying an air-fuel mixture AF, which is a mixture of combustion air A flowing through the intake line 11 and gas fuel F, to the combustion chamber 3, and an exhaust port 14 communicating with the combustion chamber 3 and for discharging exhaust gas Ge generated by combustion of the air-fuel mixture AF from the combustion chamber 3. The cylinder head 10 is provided with a spark plug 16 for igniting the air-fuel mixture AF supplied into the combustion chamber 3. The power-generator engine 1 further includes an intake valve 13 for opening and closing the intake port 12 and an exhaust valve 15 for opening and closing the exhaust port 14. In the embodiment illustrated in FIG. 2 , the power-generator engine 1 is configured to supply gas fuel F to the intake port 12 and mix the gas fuel F with combustion air A, thus employing so-called port injection. Note that a casing member such as a rocker case may be provided between the rocker cover 4 and the cylinder head 10. Furthermore, the present disclosure does not limit the method of mixing the combustion air A and the gas fuel F to port injection. The power-generator engine 1 may also be configured to mix the combustion air A and the gas fuel F upstream of the intake port 12 (e.g., upstream of a compressor, not shown).

[0014] As shown in FIG. 1 , a cylinder block 2 has multiple combustion chambers 3 formed therein. The cylinder block 2 includes a crankcase 20 that houses a crankshaft 18 disposed below the combustion chambers 3. In one embodiment, as illustrated in FIG. 2 , the cylinder block 2 includes a cylinder housing portion 24 that houses a cylindrical cylinder 22 extending along the up-down direction D2. The crankcase 20 is disposed below the cylinder housing portion 24. A piston 26 is slidably disposed inside the cylinder 22. The combustion chamber 3 is covered from below by the piston 26 and faces a top surface 27 of the piston 26. The crankcase 20 is formed with a ventilation gas inlet 28 that can introduce a ventilation gas Gv into the crank chamber 21. The ventilation gas Gv is, for example, air Ao drawn in from outside the generator engine 1. Hereinafter, the direction in which the axis O of the crankshaft 18 extends is referred to as the axial direction D1.

[0015] The rocker cover 4 is provided above the cylinder head 10 and defines an upper space 5 that covers the upper part of the cylinder head 10. The upper space 5 is in communication with the crank chamber 21 of the crankcase 20. In one embodiment, as shown in Figure 2, the generator engine 1 includes a communication passage forming portion 30 that has a communication passage 31 formed therein that connects the crank chamber 21 and the upper space 5. The rocker cover 4 has a blow-by gas discharge port 32 formed at its upper part to which the breather line 6 is connected.

[0016] 2 , the generator engine 1 further includes a valve drive device 17 provided in the upper space 5 and a power transmission device 19 provided in the communication passage 31. The valve drive device 17 drives the intake valve 13 and the exhaust valve 15. The power transmission device 19 transmits the rotational motion of a crankshaft 18 to the valve drive device 17. The power transmission device 19 includes, for example, a camshaft 19a that is rotated by the rotation of the crankshaft 18 transmitted by gears, and a push rod 19b that converts the rotation of the camshaft 19a into reciprocating linear motion and transmits it to the valve drive device 17. This type of valve mechanism is known as an overhead valve type.

[0017] The flow of blow-by gas Gb will now be described. As shown in FIG. 2 , during operation of the generator engine 1 according to one embodiment, blow-by gas Gb leaks into the crank chamber 21 through the gap between the cylinder 22 and the piston 26. Because the blow-by gas Gb contains hydrogen, the hydrogen concentration in the crank chamber 21 gradually increases. The generator engine 1 introduces ventilation gas Gv through the ventilation gas inlet 28 to dilute the hydrogen concentration, thereby reducing the hydrogen concentration in the crank chamber 21 below the lower limit of the flammable range. Furthermore, when the pressure in the crank chamber 21 increases due to the introduction of ventilation gas Gv into the crank chamber 21, the gas in the crank chamber 21 flows into the upper space 5 through the communication passage 31, which has a relatively low pressure. The blow-by gas Gb that has flowed into the upper space 5 flows into the breather line 6 through the blow-by gas outlet 32 ​​(and is discharged to the outside of the rocker cover 4).

[0018] 1 , the breather line 6 has a blow-by gas flow path 7 formed therein through which the blow-by gas Gb discharged from the upper space 5 flows. The breather line 6 includes a plurality of breather branches 34, a breather collection portion 36, and a breather circulation portion 38.

[0019] Each of the plurality of breather branches 34 is connected to the upper space 5, through which the blow-by gas Gb flows. In one embodiment, as illustrated in Fig. 1 , the generator engine 1 includes a plurality of rocker covers 4 that are independent of one another and the same number as the number of combustion chambers 3. The breather line 6 includes the same number of breather branches 34 as the number of combustion chambers 3. The plurality of rocker covers 4 are arranged on opposite sides of the axis O.

[0020] The breather collection 36 is connected to each of the plurality of breather branches 34. In one embodiment, the power generation engine 1 includes one breather line 6, and this one breather line 6 includes one breather collection 36 that is connected to all of the breather branches 34. In some embodiments, the power generation engine 1 includes multiple breather lines 6.

[0021] The breather circulation portion 38 extends to one side in the axial direction D1 from a breather junction end 40, which is one end connected to the breather collecting portion 36. The breather junction end 40 is one end on the upstream side of both ends of the breather circulation portion 38 in the flow direction in which the blow-by gas Gb flows through the breather line 6. The position of the breather junction end 40 in the axial direction D1 is not particularly limited, and may be, for example, the same position as the wall surface on one side in the axial direction D1 of the rocker cover 4 that is located closest to one side in the axial direction D1.

[0022] 1 , the exhaust line 8 has an exhaust flow path 9 formed therein through which the exhaust gas Ge discharged from the combustion chamber 3 flows. The exhaust line 8 includes a plurality of exhaust branch portions 42, an exhaust collection portion 44, and an exhaust flow portion 46.

[0023] Each of the plurality of exhaust branches 42 is connected to the combustion chamber 3, and the exhaust gas Ge flows into the exhaust branches 42. In one embodiment, one exhaust branch 42 is connected to one combustion chamber 3 via the exhaust port 14.

[0024] The exhaust manifold 44 is connected to each of the multiple exhaust branches 42. In one embodiment, the power-generating engine 1 includes one exhaust line 8, and this one exhaust line 8 includes one exhaust manifold 44 that is connected to all of the exhaust branches 42.

[0025] The exhaust flow section 46 extends from an exhaust merging end 48, which is one end connected to the exhaust collection section 44, to the other side in the axial direction D1. The exhaust merging end 48 is the upstream end of both ends of the exhaust flow section 46 in the flow direction in which the exhaust gas Ge flows through the exhaust line 8. The position of the exhaust merging end 48 in the axial direction D1 is not particularly limited, and may be, for example, the same position as the wall surface on the other side in the axial direction D1 of the rocker cover 4 that is located closest to the other side in the axial direction D1, or the same position as the wall surface on the other side in the axial direction D1 of the cylinder head 10.

[0026] Although not shown, the power generation engine 1 may further include a turbocharger having a turbine that rotates using the energy of the exhaust gas Ge, and a compressor that is mechanically connected to the turbine and driven to rotate by the turbine, thereby compressing the combustion air A or the mixture AF (when the combustion air A and the gas fuel F are mixed upstream of the compressor).

[0027] (Operations and Effects) The operations and effects of the generator engine 1 according to one embodiment will be described. The blow-by gas Gb flowing through the breather line 6 may contain hydrogen. According to one embodiment, the breather flow portion 38 of the breather line 6 extends to one side in the axial direction D1, and the exhaust flow portion 46 of the exhaust line 8 extends to the other side in the axial direction D1. This allows the breather flow portion 38 to be separated from the exhaust flow portion 46 through which high-temperature exhaust gas Ge flows. This prevents heat from being transferred to the breather flow portion 38, thereby preventing unintended malfunctions due to ignition of hydrogen in the breather line 6. Furthermore, because the breather flow portion 38 is separated from the high-temperature exhaust flow portion 46, hydrogen leaking from the breather flow portion 38 is prevented from reaching the exhaust flow portion 46, preventing unintended ignition of the leaked hydrogen.

[0028] <Power generating set> (Configuration) Fig. 3 is a diagram showing a schematic configuration of a power generating set 50 including the power generating engine 1 according to one embodiment. As shown in Fig. 3, the power generating set 50 includes the power generating engine 1, a generator 52, and an enclosure 54.

[0029] The generator 52 includes a rotor connected to the crankshaft 18 of the generator engine 1, and is configured to be rotationally driven by the generator engine 1. The generator 52 is disposed on one side of the breather junction end 40 in the axial direction D1 (i.e., forward in the front-to-rear direction D3). The generator 52 is disposed on one side of the cylinder block 2 in the axial direction D1. The generator 52 is disposed below the breather junction end 40.

[0030] The enclosure 54 has a box shape and includes a power chamber 55 that houses the generator 52 and the power-generator engine 1. In the embodiment illustrated in Fig. 3, the enclosure 54 is elongated in one horizontal direction. Hereinafter, this one direction will be referred to as the front-rear direction D3. The power-generator engine 1 is disposed so that the axis O of the crankshaft 18 extends along the front-rear direction D3. In the present disclosure, the axial direction D1 and the front-rear direction D3 are the same direction.

[0031] The enclosure 54 includes a floor 56 including an installation surface 57 on which the cylinder block 2 is placed, a front wall 58 that covers the power chamber 55 from the front side in the front-to-rear direction D3, a rear wall 60 that covers the power chamber 55 from the rear side in the front-to-rear direction D3, a roof 62 that is connected to the front wall 58 and the rear wall 60 and covers the power chamber 55 from above, and a pair of side walls (not shown) (a pair of side walls facing each other in the depth direction of the paper in FIG. 3 ). The power chamber 55 is defined by being surrounded by the floor 56, the front wall 58, the rear wall 60, the roof 62, and the pair of side walls.

[0032] The enclosure 54 includes an intake hood 65 having an inlet 64 formed therein for taking in air Ao from the outside into the power chamber 55, and an exhaust duct 66 having an exhaust port 67 formed therein for discharging the air Ao taken in from the power chamber 55. The intake hood 65 is attached to the surface of the front wall 58 opposite the power chamber 55 side. The inlet 64 of the intake hood 65 is located forward of the breather junction end 40 in the fore-and-aft direction D3 (on one side in the axial direction D1). The inlet 64 opens downward to the outside of the enclosure 54 (atmospheric space). The exhaust duct 66 is attached to the surface of the rear wall 60 opposite the power chamber 55 side. The exhaust port 67 of the exhaust duct 66 opens upward to the outside of the enclosure 54 (atmospheric space). The exhaust port 67 is located rearward of the exhaust merging end 48 in the front-rear direction D3 (on the other side in the axial direction D1).

[0033] As shown in Figure 3, the power generating set 50 takes in air Ao into the power chamber 55 through the intake port 64. The air Ao taken into the power chamber 55 flows toward the exhaust port 67 and is discharged from the power chamber 55 through the exhaust port 67. In other words, the air Ao flows through the power chamber 55 from the front to the rear in the front-to-rear direction D3. The generator engine 1 bleeds the air Ao from the power chamber 55 as combustion air A. The generator engine 1 bleeds the air Ao from the power chamber 55 as ventilation gas Gv.

[0034] 3 , the breather line 6 further includes an upward extension portion 68 extending upward from the breather flow portion 38. The upward extension portion 68 extends upward from the tip 41 of the breather flow portion 38 on the opposite side from the breather junction end 40. The upward extension portion 68 penetrates the roof portion 62 from below, and an upper end 69 opens to the outside of the enclosure 54 (atmospheric space).

[0035] The tip 41 of the breather circulation portion 38 is located above the generator 52 and overlaps the generator 52 in the front-to-rear direction D3. The breather circulation portion 38 is positioned so as to be offset from the generator 52 in the left-to-right direction (the width direction of the enclosure 54) perpendicular to the front-to-rear direction D3. Furthermore, the upward extension portion 68 also overlaps the generator 52 in the front-to-rear direction D3, but is offset from the generator 52 in the left-to-right direction. In some embodiments, the breather circulation portion 38 is inclined so that the portion from the breather junction end 40 to the tip 41 faces upward. In some embodiments, the tip 41 of the breather circulation portion 38 is located forward of the generator 52 in the front-to-rear direction D3. In some embodiments, the breather circulation portion 38 is positioned directly above the generator 52. In some embodiments, the upward extension portion 68 is positioned directly above the breather circulation portion 38.

[0036] 3 , the exhaust flow section 46 of the exhaust line 8 penetrates the rear wall section 60 from the front side in the front-rear direction D3, and an outlet end 49 opposite the exhaust merging end 48 is located outside the enclosure 54. This outlet end 49 opens to the outside of the enclosure 54.

[0037] In the embodiment illustrated in FIG. 3 , the power generating set 50 further includes a gas-liquid separator 70 and a hydrogen concentration acquisition device 72 .

[0038] The gas-liquid separator 70 is provided in the upward extending portion 68. The gas-liquid separator 70 is a so-called mist separator that separates oil mist from the blow-by gas Gb flowing within the upward extending portion 68. The gas-liquid separator 70 is disposed above the generator 52.

[0039] The hydrogen concentration acquisition device 72 acquires the concentration of hydrogen contained in the blow-by gas Gb flowing through the upper end 69 side of the upper extension portion 68 relative to the gas-liquid separation device 70. In the embodiment illustrated in FIG. 3 , the hydrogen concentration acquisition device 72 includes a bleed line 74 for bleed-off the blow-by gas Gb from the portion of the upper extension portion 68 relative to the upper end 69 side of the gas-liquid separation device 70, and a concentration sensor 76 provided in the bleed line 74 for measuring the concentration of hydrogen contained in the blow-by gas Gb flowing through the bleed line 74. The bleed line 74 extends to the outside of the enclosure 54 (atmospheric space), and a tip 75 opposite to the base end connected to the upper extension portion 68 opens to the outside of the enclosure 54. The concentration sensor 76 is provided in a portion of the bleed line 74 located inside the enclosure 54. The concentration sensor 76 is attached to the roof portion 62 or one of the pair of side walls. The concentration sensor 76 is provided near the tip 75 of the bleed line 74, and is far away from the generator engine 1. With this configuration, it is possible to suppress ignition of hydrogen contained in the blow-by gas Gb bled in order to measure the hydrogen concentration with the concentration sensor 76.

[0040] Although not shown, in some embodiments, the power generation set 50 further includes an alarm device that issues an alarm when the hydrogen concentration acquired by the hydrogen concentration acquisition device 72 exceeds a preset threshold. Although not shown, in some embodiments, the power generation set 50 further includes a stop device that stops operation of the power generation engine 1 when the hydrogen concentration acquired by the hydrogen concentration acquisition device 72 exceeds a preset threshold.

[0041] (Operations and Effects) The operations and effects of the power generating set 50 will now be described. According to the power generating set 50 shown in Fig. 3, the breather flow section 38 is located upstream of the exhaust flow section 46 in the direction of flow of the air Ao inside the power chamber 55. Therefore, the flow of air Ao further suppresses the transfer of heat from the exhaust flow section 46 to the breather flow section 38, making it possible to prevent unintended malfunctions due to ignition of hydrogen in the breather line 6. Furthermore, because the breather flow section 38 is spaced apart from the exhaust flow section 46, even if hydrogen leaks from the breather flow section 38 into the power chamber 55 and flows near the exhaust flow section 46, the hydrogen is diluted by the air Ao, reducing the possibility of malfunctions due to ignition of hydrogen.

[0042] If the concentration of hydrogen contained in the blow-by gas Gb increases, there is a higher possibility of problems such as unintended combustion occurring due to the hydrogen exceeding the lower limit of the flammable concentration range. In the power generating set 50 shown in Figure 3, since hydrogen is lighter than other gases and fluids contained in the blow-by gas Gb, the provision of the upward extension portion 68 makes it possible to smoothly guide the hydrogen to the outside of the enclosure 54 and suppress an increase in the hydrogen concentration due to hydrogen accumulation in the breather line 6.

[0043] According to the power generating set 50 shown in Figure 3, the concentration sensor 76 is provided near the tip 75 of the extraction line 74, and therefore measures the concentration of hydrogen from the blow-by gas Gb (a portion of the breather line 6 where the pressure is relatively low) which has a pressure close to atmospheric pressure. The concentration sensor 76 also obtains the concentration of hydrogen contained in the blow-by gas Gb after the oil mist has been separated by the gas-liquid separator 70. This makes it possible to improve the accuracy of obtaining the concentration of hydrogen contained in the blow-by gas Gb. The provision of the gas-liquid separator 70 makes it possible to prevent damage to the concentration sensor 76 caused by oil mist.

[0044] 3, the gas-liquid separation device 70 is disposed above the generator 52, so that the gas-liquid separation device 70 can be separated from the exhaust flow section 46, and the gas-liquid separation device 70 can be disposed upstream of the exhaust flow section 46 in the direction of flow of the air Ao inside the power chamber 55. This prevents heat from the exhaust flow section 46 from being transferred to the gas-liquid separation device 70, and prevents the temperature of the gas-liquid separation device 70 from rising.

[0045] In the embodiment illustrated in FIG. 3 , the enclosure 54 includes the intake hood 65 having the intake port 64 formed therein. However, the present disclosure is not limited to this embodiment. The intake port 64 may be formed in any position of the enclosure 54 as long as it is located forward of the breather junction end 40 in the front-to-rear direction D3. For example, the intake port 64 may be formed in the front wall portion 58, the roof portion 62, or one of the pair of side walls. In some embodiments, the intake port 64 is located forward of the upward extension portion 68 or the gas-liquid separation device 70 in the front-to-rear direction D3. With this configuration, even if blow-by gas Gb leaks from the upward extension portion 68 or the gas-liquid separation device 70, the blow-by gas Gb can be diluted with air Ao.

[0046] Similarly, although the enclosure 54 includes the exhaust duct 66 in which the exhaust port 67 is formed, the present disclosure is not limited to this embodiment. The exhaust port 67 may be formed at any position in the enclosure 54 as long as it is located rearward of the exhaust junction end 48 in the front-rear direction D3. For example, the exhaust port 67 may be formed in any of the rear wall portion 60, the roof portion 62, or one of the pair of side walls.

[0047] The contents described in each of the above embodiments can be understood, for example, as follows.

[0048] [1] An engine (1) according to the present disclosure is an engine that burns a gas fuel (F) containing hydrogen, and includes: a cylinder block (2) including a crankcase (20) in which a plurality of combustion chambers (3) are formed and in which a crankshaft (18) provided below the combustion chambers is housed; an upper space (5) covering an upper portion of a cylinder head (10) provided above the cylinder block, a rocker cover (4) that defines the upper space communicating with a crank chamber (21) of the crankcase; a breather line (6) in which a blow-by gas flow path (7) is formed, through which blow-by gas (Gb) discharged from the upper space flows; and an exhaust line (8) in which an exhaust flow path (9) is formed, through which exhaust gas (Ge) discharged from the combustion chambers flows. The breather line includes a plurality of breather branches (34) that are connected to the upper space and into which the blow-by gas flows, a breather collection section (36) that is connected to each of the plurality of breather branches, and a breather circulation section (38) that extends from a breather junction end (40) that is one end that is connected to the breather collection section to one side in the axial direction (D1) of the crankshaft, and the exhaust line includes a plurality of exhaust branches (42) that are connected to the combustion chamber and into which the exhaust gas flows, an exhaust collection section (44) that is connected to each of the plurality of exhaust branches, and an exhaust circulation section (46) that extends from an exhaust junction end (48) that is one end that is connected to the exhaust collection section to the other side in the axial direction.

[0049] According to the configuration described in [1] above, the breather flow portion of the breather line extends to one side in the axial direction, and the exhaust flow portion of the exhaust line extends to the other side in the axial direction, so that the breather flow portion can be separated from the exhaust flow portion through which high-temperature exhaust gas flows. This prevents heat from being transferred from the exhaust flow portion to the breather flow portion, thereby preventing unintended malfunctions due to ignition of hydrogen. Furthermore, because the breather flow portion is separated from the high-temperature exhaust flow portion, hydrogen leaking from the breather flow portion is prevented from reaching the exhaust flow portion, preventing unintended ignition of the leaked hydrogen.

[0050] [2] A power generating set (50) according to the present disclosure comprises the engine described in [1] above, which drives a generator by combustion of the gas fuel, and an enclosure (54) in which a power chamber (55) is formed to house the generator and the engine, wherein the enclosure has an intake port (64) formed on one side of the breather junction end in the axial direction for taking in air (Ao) into the power chamber, and an exhaust port (67) formed on the other side of the exhaust junction end in the axial direction for discharging the air taken into the power chamber from the power chamber.

[0051] According to the configuration described in [2] above, the breather passage is located upstream of the exhaust passage in the direction of air flow in the power chamber, which further suppresses heat transfer from the exhaust passage to the breather passage, thereby preventing unintended malfunctions due to hydrogen ignition. Furthermore, because the breather passage is spaced apart from the exhaust passage, even if hydrogen leaks from the breather passage and reaches the vicinity of the exhaust passage, it is diluted with air, reducing the possibility of malfunctions due to hydrogen ignition.

[0052] [3] In some embodiments, in the configuration described in [2] above, the breather line further includes an upward extension portion (68) extending upward from the breather flow portion and having an upper end (69) opening to the outside of the enclosure.

[0053] If the concentration of hydrogen contained in the blow-by gas increases, the possibility of problems such as unintended combustion occurring due to exceeding the lower limit of the flammable concentration range increases. According to the configuration described in [3] above, since hydrogen is lighter than other gases and fluids contained in the blow-by gas, the provision of the upward extension portion allows the hydrogen to be smoothly guided to the outside of the enclosure, and an increase in the hydrogen concentration due to accumulation in the breather line can be suppressed.

[0054] [4] In some embodiments, the configuration described in [3] above further comprises a gas-liquid separator (70) provided in the upper extension portion for separating liquid from the blow-by gas flowing within the upper extension portion, and a hydrogen concentration acquisition device (72) for acquiring the concentration of hydrogen contained in the blow-by gas flowing on the upper end side of the upper extension portion relative to the gas-liquid separator.

[0055] According to the configuration described in [4] above, the hydrogen concentration acquisition device acquires the concentration of hydrogen contained in the blow-by gas after the liquid such as oil mist has been separated by the gas-liquid separator, thereby improving the accuracy of acquiring the concentration of hydrogen contained in the blow-by gas.

[0056] [5] In some embodiments, in the configuration described in [4] above, the generator is arranged on one side of the breather junction end in the axial direction, and the gas-liquid separation device is arranged above the generator.

[0057] According to the configuration described in [5] above, the gas-liquid separator can be spaced apart from the exhaust gas flow section and positioned upstream of the exhaust gas flow section in the direction of air flow in the power chamber, thereby suppressing transfer of heat from the exhaust gas flow section to the gas-liquid separator and suppressing a temperature rise in the gas-liquid separator.

[0058] REFERENCE SIGNS LIST 1 generator engine 2 cylinder block 3 combustion chamber 4 rocker cover 5 upper space 6 breather line 7 blow-by gas flow path 8 exhaust line 9 exhaust flow path 10 cylinder head 11 intake line 12 intake port 13 intake valve 14 exhaust port 15 exhaust valve 16 spark plug 17 valve drive device 18 crankshaft 19 power transmission device 19a camshaft 19b push rod 20 crankcase 21 crank chamber 22 cylinder 24 cylinder housing section 26 piston 27 piston top surface 28 ventilation gas inlet 30 communication passage forming section 31 communication passage 32 blow-by gas outlet 34 breather branch 36 breather collection section 38 breather flow section 40 breather merging end 41 tip of breather flow section DESCRIPTION OF SYMBOLS 42 Exhaust branch section 44 Exhaust collection section 46 Exhaust flow section 48 Exhaust merging end 50 Generating set 52 Generator 54 Enclosure 55 Power room 56 Floor section 57 Floor installation surface 58 Front wall section 60 Rear wall section 62 Roof section 64 Intake port 65 Intake hood 66 Exhaust duct 67 Exhaust port 68 Upward extension section 69 Upper end of upward extension section 70 Gas-liquid separator 72 Hydrogen concentration acquisition device 74 Bleed line 75 End of bleed line 76 Concentration sensor A Combustion air Ao Air D1 Axial direction D2 Up-down direction D3 Forward-backward direction F Gaseous fuel Gb Blow-by gas Ge Exhaust gas Gv Ventilation gas O Axis of crankshaft

Claims

1. An engine that burns gas fuel containing hydrogen, comprising: a cylinder block having a plurality of combustion chambers formed therein and including a crankcase that houses a crankshaft disposed below the combustion chambers; a rocker cover that defines an upper space that covers an upper part of a cylinder head disposed above the cylinder block and that communicates with a crank chamber of the crankcase; a breather line having a blow-by gas flow path formed therein through which blow-by gas discharged from the upper space flows; and an exhaust line having an exhaust flow path formed therein through which exhaust gas discharged from the combustion chamber flows, wherein the breather line includes a plurality of breather branches that communicate with the upper space and into which the blow-by gas flows, a breather collection part connected to each of the plurality of breather branches, and a breather circulation part that extends from a breather junction end that is one end connected to the breather collection part to one side in the axial direction of the crankshaft, an exhaust line including a plurality of exhaust branches that communicate with the combustion chamber and into which the exhaust gas flows, an exhaust collection section that is connected to each of the plurality of exhaust branches, and an exhaust flow section that extends from an exhaust junction end that is one end connected to the exhaust collection section to the other side in the axial direction.

2. A power generating set according to claim 1, comprising: an engine that drives a generator by combustion of the gas fuel; and an enclosure in which a power chamber is formed to house the generator and the engine, wherein the enclosure has an intake port formed on one side of the breather junction end in the axial direction for taking in air into the power chamber, and an exhaust port formed on the other side of the exhaust junction end in the axial direction for discharging the air taken into the power chamber from the power chamber.

3. The power generating set according to claim 2, wherein the breather line further includes an upward extension portion that extends upward from the breather circulation portion and has an upper end that opens to the outside of the enclosure.

4. The power generating set according to claim 3, further comprising: a gas-liquid separator provided in the upper extension portion for separating liquid from the blow-by gas flowing within the upper extension portion; and a hydrogen concentration acquisition device for acquiring the concentration of hydrogen contained in the blow-by gas flowing on the upper end side of the upper extension portion relative to the gas-liquid separator.

5. The power generating set according to claim 4, wherein the generator is disposed on one side of the breather junction end in the axial direction, and the gas-liquid separator is disposed above the generator.

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