Oxidation catalyst temperature raising system, internal combustion engine system, and oxidation catalyst device temperature raising method

Abstract

This oxidation catalyst temperature raising system is provided with: an exhaust line through which exhaust gas discharged from an internal combustion engine flows; a catalyst case provided on the exhaust line and accommodating an oxidation catalyst device including a plurality of oxidation catalyst elements configured to oxidize the exhaust gas; and at least one temperature-increasing gas pipe through which a temperature-increasing gas for increasing the temperature of the oxidation catalyst device flows, the temperature-increasing gas pipe being disposed inside the catalyst case and between a pair of oxidation catalyst elements disposed adjacent to each other among the plurality of oxidation catalyst elements.

Description

Technical Field

[0001] The present invention relates to an oxidation catalyst temperature increasing system for increasing the temperature of an oxidation catalyst device, an internal combustion engine system equipped with the oxidation catalyst temperature increasing system, and an oxidation catalyst device temperature increasing method.

[0002] This application claims priority based on Japanese Patent Application No. 2023-065026 filed with the Japan Patent Office on April 12, 2023, and incorporates the contents thereof herein. Background Art

[0003] The oxidation catalyst device includes an oxidation catalyst for oxidizing exhaust gas emitted from the internal combustion engine. To maximize the performance of the oxidation catalyst (eg, a methane oxidation catalyst) included in the oxidation catalyst device, the oxidation catalyst device needs to be maintained at a relatively high temperature.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6162383 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] While the oxidation catalyst device is in use, the heat energy contained in the exhaust gas introduced into it, or the heat energy generated by the oxidation reaction of the exhaust gas, is transferred to the oxidation catalyst device, thereby maintaining a relatively high temperature. In contrast, when the oxidation catalyst device is not in use, it is cooled by the surrounding outside air, and sometimes reaches a temperature similar to that of the outside air. In this case, a long catalyst warm-up time may be required at the start of use until the oxidation catalyst can function effectively.

[0009] Patent Document 1 discloses a method in which a catalyst for treating ammonia or nitrogen oxides is housed in a housing, and a bypass flow path for the exhaust gas is provided on the outer periphery of the housing, along the flow direction of the exhaust gas flowing within the housing. In the invention described in Patent Document 1, the exhaust gas flowing through the bypass flow path can heat the outer periphery of the catalyst, but the inner periphery of the catalyst is not sufficiently insulated, potentially requiring a long time to warm up the catalyst until the inner periphery of the catalyst can function effectively.

[0010] In view of the above, an object of at least one embodiment of the present invention is to provide an oxidation catalyst heating system, an internal combustion engine system, and an oxidation catalyst device heating method capable of effectively heating an oxidation catalyst device while the oxidation catalyst device is not in use.

[0011] Means for solving technical problems

[0012] An oxidation catalyst temperature increasing system according to at least one embodiment of the present invention includes:

[0013] an exhaust line for the flow of exhaust gas from the internal combustion engine;

[0014] a catalyst housing provided in the exhaust pipe and accommodating an oxidation catalyst device including a plurality of oxidation catalyst elements configured to oxidize the exhaust gas; and

[0015] At least one temperature-increasing gas pipe flows a temperature-increasing gas for increasing the temperature of the oxidation catalyst device, and is disposed inside the catalyst housing and between a pair of adjacent oxidation catalyst elements among the plurality of oxidation catalyst elements.

[0016] An internal combustion engine system according to at least one embodiment of the present invention includes:

[0017] the oxidation catalyst heating system;

[0018] the internal combustion engine; and

[0019] The first exhaust path switching device is configured to switch the path of the exhaust gas discharged from the internal combustion engine. In the internal combustion engine system,

[0020] The oxidation catalyst device includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas.

[0021] The internal combustion engine includes a dual-fuel engine capable of switching between a first fuel containing methane in the exhaust gas component and a second fuel containing no methane in the exhaust gas component.

[0022] The first exhaust path switching device is configured to guide the exhaust gas exhausted from the internal combustion engine to the catalyst housing while the internal combustion engine is operating with the first fuel as fuel, and is configured to guide the exhaust gas exhausted from the internal combustion engine to the at least one heated gas piping while the internal combustion engine is operating with the second fuel as fuel.

[0023] At least one embodiment of the present invention relates to an oxidation catalyst device temperature-raising method for raising the temperature of an oxidation catalyst device configured to oxidize exhaust gas discharged from an internal combustion engine. In the oxidation catalyst device temperature-raising method,

[0024] The oxidation catalyst device includes a plurality of oxidation catalyst elements, each of which includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas.

[0025] The internal combustion engine includes a dual-fuel engine capable of switching between a first fuel containing methane in the exhaust gas component and a second fuel containing no methane in the exhaust gas component.

[0026] The oxidation catalyst device temperature raising method comprises:

[0027] a first operating step of introducing the exhaust gas exhausted from the internal combustion engine into a catalyst case accommodating the oxidation catalyst device while the internal combustion engine is operating using the first fuel; and

[0028] The second operating step is to introduce the exhaust gas discharged from the internal combustion engine into at least one heated gas piping while the internal combustion engine is operating with the second fuel as fuel. The at least one heated gas piping is arranged inside the catalyst housing and between a pair of adjacent oxidation catalyst elements among the multiple oxidation catalyst elements.

[0029] Effects of the Invention

[0030] According to at least one embodiment of the present invention, an oxidation catalyst temperature increasing system, an internal combustion engine system, and an oxidation catalyst device temperature increasing method are provided that can effectively increase the temperature of an oxidation catalyst device while the oxidation catalyst device is not in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of an internal combustion engine system according to one embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of an internal combustion engine system according to one embodiment of the present invention.

[0033] Figure 3 It is a schematic cross-sectional view of a catalyst case of an oxidation catalyst temperature increasing system according to one embodiment of the present invention.

[0034] Figure 4 yes Figure 3 The schematic cross-sectional view of the catalyst shell taken along line AB is shown.

[0035] Figure 5 yes Figure 3 The schematic cross-sectional view of the catalyst shell taken along line CD is shown.

[0036] Figure 6 yes Figure 3 The schematic cross-sectional view of the catalyst shell taken along line EF is shown.

[0037] Figure 7 It is a schematic cross-sectional view of a catalyst case of an oxidation catalyst temperature increasing system according to one embodiment of the present invention.

[0038] Figure 8 yes Figure 7 The schematic cross-sectional view of the catalyst shell taken along line GH is shown. DETAILED DESCRIPTION

[0039] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described as embodiments or shown in the accompanying drawings are not intended to limit the scope of the present invention and are merely illustrative examples.

[0040] (Internal combustion engine system)

[0041] Figure 1 and Figure 2 Each of them is a schematic diagram of an internal combustion engine system 1 according to an embodiment of the present invention. Figure 1 and Figure 2 As shown, the internal combustion engine system 1 includes an oxidation catalyst heating system 2 and a first internal combustion engine 11. The oxidation catalyst heating system 2 includes a first exhaust pipe 12 through which first exhaust gas, the exhaust gas discharged from the internal combustion engine 11, flows. The first exhaust pipe 12 forms a flow path for the first exhaust gas to flow, and is formed, for example, by piping. The internal combustion engine system 1 may further include a first generator 110 connected to the first internal combustion engine 11 and generating electricity using the power generated by the first internal combustion engine 11.

[0042] (Oxidation catalyst heating system)

[0043] The oxidation catalyst temperature increasing system 2 according to some embodiments is mounted on the internal combustion engine system 1. Figure 1 and Figure 2 As shown, the oxidation catalyst temperature increasing system 2 includes the first exhaust pipe 12 , the oxidation catalyst device 3 , and a catalyst housing 4 . The catalyst housing 4 is provided on the first exhaust pipe 12 to accommodate the oxidation catalyst device 3 .

[0044] In the following description, when simply referred to as the upstream side, it refers to the upstream side along the main flow direction of the fluid in the portion or region involved in the directional description. Similarly, in the following description, when simply referred to as the downstream side, it refers to the downstream side along the main flow direction of the fluid in the portion or region involved in the directional description.

[0045] (Catalyst housing)

[0046] The flow direction of the first exhaust gas flowing through the catalyst case 4 is defined as a first direction RD1. In the illustrated embodiment, the first exhaust gas flowing through the catalyst case 4 flows vertically from bottom to top. That is, in the illustrated embodiment, the first direction RD1 indicates a direction from vertically downward to vertically upward.

[0047] Figure 3 and Figure 7 Each of them is a schematic cross-sectional view of the catalyst case 4 of the oxidation catalyst temperature increasing system 2 according to one embodiment of the present invention. Figure 3 and Figure 7 ] shows a cross section of the catalyst case 4 along the first direction RD1. Figure 4 yes Figure 3 The catalyst housing 4 is shown as a schematic cross-sectional view taken along line AB. Figure 5 yes Figure 3 The catalyst housing 4 is shown as a schematic cross-sectional view taken along line CD. Figure 6 yes Figure 3 The catalyst housing 4 is shown as a schematic cross-sectional view taken along line EF. Figure 8 yes Figure 7 The catalyst housing 4 is shown as a schematic cross-sectional view taken along line GH.

[0048] In the illustrated embodiment, Figure 3 and Figure 7 As shown, the catalyst case 4 is formed in a rectangular cylindrical shape extending in a first direction (vertical direction) and includes a case body 41 having a first internal space 40 through which the first exhaust gas flows from upstream to downstream in the first direction.

[0049] The oxidation catalyst device 3 is disposed in the first internal space 40 and extends in a direction intersecting the first direction (in the illustrated example, a horizontal direction perpendicular to the first direction). The oxidation catalyst device 3 divides the first internal space 40 into upstream and downstream sides in the first direction.

[0050] The housing body 41 has a first exhaust gas inlet 42 formed at an upstream end portion in the first direction for introducing the first exhaust gas from the exterior of the housing body 41 into the first interior space 40. The housing body 41 has a first exhaust gas outlet 43 formed at a downstream end portion in the first direction for discharging the first exhaust gas from the first interior space 40 to the exterior of the housing body 41.

[0051] like Figure 1 and Figure 2 As shown, the first exhaust line 12 includes a first upstream exhaust line 12A for guiding the first exhaust gas from the internal combustion engine 11 to the catalyst housing 4, and a first downstream exhaust line 12B for guiding the first exhaust gas from the catalyst housing 4 to the downstream side in the flow direction of the first exhaust gas. The upstream end of the first upstream exhaust line 12A is connected to the internal combustion engine 11, and the downstream end is connected to the first exhaust gas inlet 42 of the catalyst housing 4. The upstream end of the first downstream exhaust line 12B is connected to the first exhaust gas outlet 43 of the catalyst housing 4.

[0052] The first exhaust gas flows through the first exhaust line 12 and is guided from the first exhaust inlet 42 to the first internal space 40. When the first exhaust gas guided into the first internal space 40 passes through the oxidation catalyst device 3, the oxidation catalyst contained in the oxidation catalyst device 3 promotes oxidation of at least one exhaust component (e.g., methane). The first exhaust gas that has passed through the oxidation catalyst device 3 is discharged from the first exhaust outlet 43 to the outside of the housing body 41 (the first downstream exhaust line 12B).

[0053] (Oxidation Catalyst Device)

[0054] like Figure 4 and Figure 5 As shown, the oxidation catalyst device 3 includes a plurality of oxidation catalyst elements 31 configured to oxidize the first exhaust gas. Each of the plurality of oxidation catalyst elements 31 contains an oxidation catalyst that promotes oxidation of at least one of the components contained in the exhaust gas (exhaust components). In the illustrated embodiment, each of the plurality of oxidation catalyst elements 31 is formed as a hexahedron (e.g., a cube or a rectangular parallelepiped) having six quadrilateral faces. Each of the plurality of oxidation catalyst elements 31 contains a methane oxidation catalyst that promotes oxidation of methane contained in the exhaust gas.

[0055] To maximize the performance of the oxidation catalyst (e.g., a methane oxidation catalyst) contained in the oxidation catalyst device 3, the oxidation catalyst device 3 must be maintained at a relatively high temperature. While the oxidation catalyst device 3 is in use, the thermal energy of the first exhaust gas flowing through the first internal space 40 of the catalyst housing 4, or the thermal energy generated by the oxidation reaction of the first exhaust gas, is transferred to the oxidation catalyst device 3, thereby maintaining the relatively high temperature of the oxidation catalyst device 3. In contrast, when the oxidation catalyst device 3 is not in use, it is cooled by the outside air surrounding the catalyst housing 4, and may reach a temperature similar to that of the outside air. In this case, a long catalyst warm-up period may be required upon initial use of the oxidation catalyst device 3 until the oxidation catalyst can fully exert its performance.

[0056] (Heating gas piping)

[0057] like Figure 1 and Figure 2 As shown, the oxidation catalyst heating system 2 further includes at least one (in the illustrated example, a plurality) heating gas pipes 5. The oxidation catalyst heating system 2 is configured to heat the oxidation catalyst contained in the oxidation catalyst device 3 using the heating gas flowing through the at least one heating gas pipe 5.

[0058] exist Figure 1In the embodiment shown, each of the plurality of temperature-increasing gas pipes 5 is used to supply the first exhaust gas flow discharged from the first internal combustion engine 11 as the temperature-increasing gas. Figure 2 In the embodiment shown, the internal combustion engine system 1 further includes a second internal combustion engine 13 different from the first internal combustion engine 11 and a second exhaust pipe 14 through which the second exhaust gas discharged from the internal combustion engine 13 flows. The internal combustion engine system 1 may further include a second generator 130 connected to the second internal combustion engine 13 and generating electricity using the power generated by the second internal combustion engine 13. Figure 2 In the illustrated embodiment, each of the plurality of heating gas pipes 5 is configured to carry the second exhaust gas discharged from the second internal combustion engine 13 as the heating gas. Furthermore, the heating gas is not limited to the first exhaust gas or the second exhaust gas, as long as it is a gaseous heat medium capable of heating the oxidation catalyst device 3. The heating gas may be exhaust gas discharged from the main engine, i.e., the propulsion internal combustion engine of the vessel.

[0059] like Figure 4 、 Figure 5 and Figure 8 As shown, the plurality of temperature-increasing gas pipes 5 are arranged inside the catalyst case 4 and between a pair of adjacently arranged oxidation catalyst elements 31 among the plurality of oxidation catalyst elements 31 .

[0060] In the illustrated embodiment, each of the plurality of temperature-increasing gas pipes 5 extends in the same direction as the other temperature-increasing gas pipes 5. Figure 4 and Figure 8 As shown, the plurality of heating gas pipes 5 are arranged at intervals in a direction intersecting (orthogonal in the example shown) the extending direction of the heating gas pipe 5 (the left-right direction in the figure) when viewed from the first direction RD1. Figure 4 and Figure 8 As shown, each of the plurality of oxidation catalyst elements 31 is disposed between a pair of adjacent heating gas pipes 5 in a direction intersecting the extending direction of the heating gas pipes 5 when viewed from the first direction RD1. Preferably, each of the plurality of oxidation catalyst elements 31 abuts against the adjacent pair of heating gas pipes 5. Alternatively, the oxidation catalyst element 31 may be disposed between a pair of heating gas pipes 5 spaced apart in the first direction.

[0061] According to the above configuration, while the oxidation catalyst device 3 is not in use, the temperature of the oxidation catalyst device 3 can be increased by the heated gas flowing through the at least one heated gas pipe 5. The at least one heated gas pipe 5 is disposed between a pair of oxidation catalyst elements 31 disposed adjacent to each other within the catalyst housing 4. Therefore, the thermal energy of the heated gas flowing through the heated gas pipe 5 can be efficiently transferred to each of the pair of oxidation catalyst elements 31 sandwiching the heated gas pipe 5. This allows the entire oxidation catalyst device 3 to be heated effectively, shortening the catalyst heating time required for the oxidation catalyst to function properly when the oxidation catalyst device 3 is put into use.

[0062] In some embodiments, the oxidation catalyst device 3 (oxidation catalyst element 31) includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas. This configuration requires maintaining the methane oxidation catalyst (oxidation catalyst device 3) at a relatively high temperature to maximize its performance. However, the heated gas flowing through the at least one heated gas pipe 5 can increase the temperature of the methane oxidation catalyst. This shortens the catalyst heating time required for the methane oxidation catalyst to exhibit its performance upon initial use of the oxidation catalyst device 3.

[0063] In some embodiments, as Figure 1 and Figure 2 As shown, the plurality of heating gas pipes 5 each extend in a direction intersecting the first direction RD1. With this configuration, the plurality of heating gas pipes 5 each extend in a direction intersecting the flow direction (first direction RD1) of the exhaust gas flowing within the catalyst housing 4. Therefore, the thermal energy of the heating gas flowing through these heating gas pipes 5 can be efficiently transferred to the entire oxidation catalyst device 3 disposed within the catalyst housing 4. This effectively increases the temperature of the oxidation catalyst device 3.

[0064] In some embodiments, as Figure 5 As shown, each of the plurality of heating gas pipes 5 is formed of a rectangular conduit having a rectangular cross-sectional shape having a pair of long sides and a pair of short sides. Figure 5 As shown, in each of the plurality of temperature-increasing gas pipes 5 , a pair of long sides 51 , 52 of the temperature-increasing gas pipe 5 having the long sides abut against a pair of oxidation catalyst elements 31 disposed adjacent to the temperature-increasing gas pipe 5 .

[0065] According to the above configuration, the outer side surfaces of the pair of relatively large long sides 51, 52 of each of the plurality of heating gas pipes 5 abut against the oxidation catalyst element 31. Through the pair of long sides 51, 52 with a large heat transfer area, the heat energy of the heating gas flowing through the heating gas pipes 5 having the pair of long sides 51, 52 can be directly and efficiently transferred to each of the oxidation catalyst elements 31 facing the pair of long sides 51, 52. This allows the oxidation catalyst device 3 to be heated efficiently.

[0066] In some embodiments, the at least one heating gas pipe 5 includes a plurality of heating gas pipes 5, such as Figure 4 and Figure 8 As shown, when viewed from the first direction RD1, the plurality of heating gas pipes 5 are spaced apart in a direction intersecting the direction in which the heating gas pipes 5 extend (the horizontal direction in the figure) (in the illustrated example, a direction perpendicular to the direction in which the heating gas pipes 5 extend, i.e., the vertical direction in the figure). The oxidation catalyst heating system 2 further includes a plurality of partitions 6. When viewed from the first direction RD1, both ends of the plurality of partitions 6 are connected to a pair of heating gas pipes 5 adjacent to each other in a direction intersecting the direction in which the heating gas pipes 5 extend. The plurality of partitions 6 are spaced apart in the direction in which the heating gas pipes 5 extend. Each of the plurality of partitions 6 has one end connected to one heating gas pipe 5 of the pair of heating gas pipes 5 and the other end connected to the other heating gas pipe 5.

[0067] In the illustrated embodiment, each of the plurality of partitions 6 is formed of a metal plate extending in a direction intersecting (orthogonal in the illustrated example) the direction in which the heating gas pipes 5 extend. Each of the plurality of partitions 6 has one end (one end) intersecting the direction in which the heating gas pipes 5 extend, secured to one of the pair of heating gas pipes 5 by welding or the like, and has the other end (the other end) intersecting the direction in which the heating gas pipes 5 extend, secured to the other of the pair of heating gas pipes 5 by welding or the like.

[0068] A plurality of spaces 400 are formed in the first internal space 40, and the plurality of spaces 400 are divided by the pair of heating gas pipes 5 and the plurality of partition plates 6 connected to the pair of heating gas pipes 5 at both ends. Figure 4 As shown, the first internal space 40 may include a plurality of spaces 400 spaced apart in the extending direction of the heating gas pipe 5 or spaced apart in a direction intersecting the extending direction of the heating gas pipe 5 .

[0069] The plurality of oxidation catalyst elements 31 are each housed in the plurality of spaces 400 described above. Each of the plurality of oxidation catalyst elements 31 is supported by at least one of the pair of heating gas pipes 5 or the pair of partitions 6 that define the space 400 containing the oxidation catalyst element 31. Preferably, each of the plurality of oxidation catalyst elements 31 abuts against the pair of partitions 6 that define the space 400 containing the oxidation catalyst element 31. In this case, the thermal energy of the heating gas flowing through the pair of heating gas pipes 5 is transferred from the pair of heating gas pipes 5 to the pair of partitions 6, and then from the pair of partitions 6 to the oxidation catalyst element 31 abutting against the pair of partitions 6. In other words, the thermal energy transferred from the pair of partitions 6 also increases the temperature of the oxidation catalyst element 31, thereby effectively increasing the temperature of the oxidation catalyst element 31.

[0070] With this configuration, each oxidation catalyst element 31 can be housed in the space 400 defined by the pair of heating gas pipes 5 and the plurality of partitions 6, thereby facilitating positioning of the oxidation catalyst element 31. Furthermore, within the oxidation catalyst element 31 housed in the space 400, thermal energy from the heating gas flowing through the pair of heating gas pipes 5 is transferred via the pair of heating gas pipes 5 and the plurality of partitions 6 surrounding the oxidation catalyst element 31. This effectively increases the temperature of the entire oxidation catalyst element 31 housed in the space 400.

[0071] When viewed from the first direction RD1, a combination of a plurality of heating gas pipes 5 spaced apart in a direction intersecting the extending direction of the heating gas pipes 5, a plurality of partitions 6 connected to both ends of the plurality of heating gas pipes 5, and a plurality of oxidation catalyst elements 31 housed in a space 400 partitioned by the plurality of heating gas pipes 5 and the plurality of partitions 6 is set as one stage. Figure 5 As shown, the oxidation catalyst temperature increasing system 2 may include a multi-stage combination arranged in a first direction.

[0072] (Flow direction of the heated gas flowing through the heated gas pipe)

[0073] In some embodiments, as Figure 4 As shown, each of the plurality of heating gas pipes 5 allows heating gas to flow from one side (right side in the figure) to the other side (left side in the figure) in the extending direction (left-right direction in the figure) of the heating gas pipe 5 . Figure 4 RD2 represents the flow direction of the temperature-increasing gas flowing in the temperature-increasing gas pipe 5 .

[0074] In some embodiments, as Figure 7 and Figure 8As shown, the above-mentioned multiple heating gas pipes 5 each include: at least one (in the example shown in the figure, multiple) first heating gas pipe 5A for supplying heating gas to flow from one side (right side in the figure) to the other side (left side in the figure) in the extension direction of the heating gas pipe 5 (left and right direction in the figure); and at least one (in the example shown in the figure, multiple) second heating gas pipe 5B for supplying heating gas to flow from the above-mentioned other side (left side in the figure) to the above-mentioned one side (right side in the figure) in the extension direction of the heating gas pipe 5. Figure 7 and Figure 8 RD2 represents the flow direction of the heating gas flowing in the first heating gas pipe 5A. Figure 7 and Figure 8 RD3 represents the flow direction of the temperature-increasing gas flowing through the second temperature-increasing gas pipe 5B.

[0075] exist Figure 7 In the embodiment shown, the heating gas pipes 5 (5A) of each stage and the heating gas pipes 5 (5B) of another stage adjacent in the first direction flow in opposite directions. Figure 8 In the illustrated embodiment, the heating gas pipes 5 (5A) of each stage flow in opposite directions to the heating gas pipes 5 (5B) of the adjacent stages. In another embodiment, the heating gas pipes 5 constituting one stage flow in the same direction, while the heating gas pipes 5 constituting another stage adjacent to the first stage may flow in opposite directions to the heating gas pipes 5 of the first stage.

[0076] According to the above configuration, by aligning the exhaust gas flowing through the at least one first heating gas pipe 5A and the exhaust gas flowing through the at least one second heating gas pipe 5B in opposite directions, it is possible to suppress the heat transfer from the heating gas flowing through the plurality of heating gas pipes 5A and 5B to the oxidation catalyst device 3 from being offset in the direction in which the heating gas pipes 5 extend. This allows the entire oxidation catalyst device 3 to be heated uniformly, shortening the catalyst heating time required for the oxidation catalyst to exhibit its performance when the oxidation catalyst device 3 is first used.

[0077] (Inlet gas duct, outlet gas duct)

[0078] A heating gas inlet for introducing heating gas from the outside into the heating gas pipe 5 is formed at one end of the plurality of heating gas pipes 5 (5A, 5B) in the direction in which the heating gas pipe 5 extends. A heating gas outlet for discharging heating gas from the heating gas pipe 5 to the outside is formed at the other end of the plurality of heating gas pipes 5 (5A, 5B) in the direction in which the heating gas pipe 5 extends.

[0079] In some embodiments, the oxidation catalyst heating system 2 further includes an inlet gas conduit 21 and an outlet gas conduit 22 mounted on the catalyst housing 4. The heating gas inlets of the plurality of heating gas pipes 5 are connected to the common inlet gas conduit 21, and the heating gas outlets are connected to the common outlet gas conduit 22.

[0080] like Figure 4 and Figure 6 As shown, an internal space 210 is formed between the inlet gas conduit 21 and the catalyst housing 4, through which the heated gas flows before being introduced into the heated gas pipe 5. The inlet gas conduit 21 is formed with an inlet port 211 for introducing the heated gas into the interior of the inlet gas conduit 21 (the internal space 210), and a plurality of communication holes 212 that connect the internal space 210 of the inlet gas conduit 21 with the heated gas inlet ports of the plurality of heated gas pipes 5, respectively.

[0081] like Figure 4 As shown, an internal space 220 is formed between the outlet gas conduit 22 and the catalyst housing 4, through which the heated gas passing through the heated gas pipe 5 flows. The outlet gas conduit 22 is formed with an exhaust port 221 for exhausting the heated gas from the interior of the outlet gas conduit 22 (internal space 220), and a plurality of communication holes 222 that connect the internal space 220 of the outlet gas conduit 22 with the heated gas exhaust ports of the plurality of heated gas pipes 5.

[0082] exist Figure 4 In the illustrated embodiment, the inlet gas conduit 21 is attached to one end of the catalyst housing 4 (the end on one side (the right side in the figure) in the direction in which the heating gas pipe 5 extends (the left-right direction in the figure)). The outlet gas conduit 22 is attached to the other end of the catalyst housing 4 (the end on the other side (the left side in the figure) in the direction in which the heating gas pipe 5 extends (the left-right direction in the figure)).

[0083] exist Figure 7 and Figure 8 In the illustrated embodiment, the inlet gas conduit 21 includes a first inlet gas conduit 21A defining an interior space 210A for the flow of heated gas before being introduced into the first heated gas pipe 5A, and a second inlet gas conduit 21B defining an interior space 210B for the flow of heated gas before being introduced into the second heated gas pipe 5B. The outlet gas conduit 22 includes a first outlet gas conduit 22A defining an interior space 220A for the flow of heated gas passing through the first heated gas pipe 5A, and a second outlet gas conduit 22B defining an interior space 220B for the flow of heated gas passing through the second heated gas pipe 5B.

[0084] The heating gas inlet ports of the plurality of first heating gas pipes 5A are connected to a common first inlet gas conduit 21A, and the heating gas outlet ports are connected to a common first outlet gas conduit 22A. The heating gas inlet ports of the plurality of second heating gas pipes 5B are connected to a common second inlet gas conduit 21B, and the heating gas outlet ports are connected to a common second outlet gas conduit 22B.

[0085] exist Figure 7 and Figure 8 In the illustrated embodiment, the first inlet gas conduit 21A and the second outlet gas conduit 22B are disposed on the aforementioned side (the right side in the figure) of the heating gas conduit 5 in the direction in which the heating gas conduit 5 extends. In the illustrated example, the second outlet gas conduit 22B is disposed on the aforementioned side of the first inlet gas conduit 21A, but may alternatively be disposed on the other side (the left side in the figure) of the first inlet gas conduit 21A.

[0086] exist Figure 7 and Figure 8 In the illustrated embodiment, the first inlet gas conduit 21A and the second outlet gas conduit 22B are formed by a first gas conduit body 44 that defines an interior space including an interior space 210A and an interior space 220B, and a partition wall 45 that divides the interior space of the first gas conduit body 44 into the interior space 210A and the interior space 220B. In the illustrated example, the partition wall 45 extends in a direction that intersects (in the illustrated example, is perpendicular to) the direction in which the heating gas piping 5 extends.

[0087] exist Figure 7 and Figure 8 In the illustrated embodiment, the second inlet gas conduit 21B and the first outlet gas conduit 22A are disposed on the other side (left side in the figure) of the heating gas conduit 5 in the direction in which the heating gas conduit 5 extends. In the illustrated example, the first outlet gas conduit 22A is disposed on the other side relative to the second inlet gas conduit 21B, but may alternatively be disposed on the one side relative to the second inlet gas conduit 21B (right side in the figure).

[0088] exist Figure 7 and Figure 8 In the illustrated embodiment, the second inlet gas conduit 21B and the first outlet gas conduit 22A are formed by a second gas conduit body 46 that defines an interior space including an interior space 210B and an interior space 220A, and a partition wall 47 that divides the interior space of the second gas conduit body 46 into the interior space 210B and the interior space 220A. In the illustrated example, the partition wall 47 extends in a direction that intersects (in the illustrated example, is perpendicular to) the direction in which the heating gas pipe 5 extends.

[0089] like Figure 7As shown, the inlet gas ducts 21A and 21B are formed with inlets 211A and 211B for introducing heated gas into the interiors (internal spaces 210A and 210B) of the inlet gas ducts 21A and 21B, and a plurality of connecting holes 212A and 212B that connect the internal spaces 210A and 210B of the inlet gas ducts 21A and 21B with the heated gas inlets of the plurality of heated gas pipes 5, respectively.

[0090] like Figure 7 As shown, the outlet gas ducts 22A and 22B are formed with exhaust ports 221A and 221B for exhausting the heated gas from the interior of the outlet gas ducts 22A and 22B (internal spaces 220A and 220B), and multiple connecting holes 222A and 222B that connect the internal spaces 220A and 220B of the outlet gas ducts 22A and 22B with the heated gas exhaust ports of the multiple heated gas pipes 5.

[0091] In the example shown in the figure, Figure 7 As shown, the first gas duct body 44 is formed with the aforementioned inlet 211A, outlet 221B, and multiple communication holes 212A. Multiple insertion holes 441, through which the second heating gas pipes 5B are respectively inserted, are formed in the first gas duct body 44. The multiple communication holes 222B are formed in the partition wall 45.

[0092] In the example shown in the figure, Figure 7 As shown, the second gas duct body 46 is formed with the aforementioned inlet 211B, outlet 221A, and multiple communication holes 212B. The second gas duct body 46 is formed with multiple insertion holes 461 through which the first heating gas pipe 5A is inserted. The multiple communication holes 222A are formed in the partition wall 47. The aforementioned inlet 211A, 211B and outlet 221A, 221B open vertically upward.

[0093] According to the above configuration, by connecting the multiple heating gas pipes 5 to the common inlet gas conduit 21, it is possible to minimize differences in the temperature or flow rate of the exhaust gas introduced from the inlet gas conduit 21 into the multiple heating gas pipes 5. Furthermore, by connecting the multiple heating gas pipes 5 to the common outlet gas conduit 22, it is possible to minimize differences in the temperature or flow rate of the exhaust gas discharged from the multiple heating gas pipes 5 into the outlet gas conduit 22. By minimizing differences in the temperature or flow rate of the exhaust gas introduced into the multiple heating gas pipes 5, thermal energy is uniformly transferred from the heating gas flowing through the multiple heating gas pipes 5 to the oxidation catalyst device 3. This allows the entire oxidation catalyst device 3 to be uniformly heated, shortening the catalyst heating time required for the oxidation catalyst to exhibit its performance when the oxidation catalyst device 3 is first used.

[0094] (Throttle)

[0095] In some embodiments, as Figure 7 As shown, the multiple heating gas pipes 5 connected to the common inlet gas conduit 21 include: a nearby heating gas pipe 5C connected to the inlet gas conduit 21 at a position relatively close to the inlet port 211 of the inlet gas conduit 21; and a distant heating gas pipe 5D connected to the inlet gas conduit 21 at a position farther away from the inlet port 211 than the nearby heating gas pipe 5C. The distance from the inlet port 211 to the heating gas inlet port of the nearby heating gas pipe 5C is shorter than that of the distant heating gas pipe 5D. Figure 7 In the embodiment shown, the remote side temperature-increasing gas pipe 5D is arranged at a position farther from the inlet port 211 of the inlet gas duct 21 in the vertical direction than the nearby side temperature-increasing gas pipe 5C. Figure 4 In the illustrated embodiment, the remote-side temperature-increasing gas pipe 5D is arranged at a position farther from the inlet port 211 of the inlet gas duct 21 in the horizontal direction than the nearby-side temperature-increasing gas pipe 5C.

[0096] In some embodiments, as Figure 7 As shown, a throttle orifice 81 having an opening area 50C smaller than the opening area 50D of the distal-side heated gas pipe 5D is provided in either the nearby heated gas pipe 5C, the connection C1 between the nearby heated gas pipe 5C and the inlet gas conduit 21, or the connection C2 between the nearby heated gas pipe 5C and the outlet gas conduit 22. Here, the opening area 50C of the nearby heated gas pipe 5C refers to the minimum area of the flow path of the heated gas flowing through the nearby heated gas pipe 5C, from the communication hole 212 of the inlet gas conduit 21 to the communication hole 222 of the outlet gas conduit 22. The opening area 50D of the distal-side heated gas pipe 5D refers to the minimum area of the flow path of the heated gas flowing through the distal-side heated gas pipe 5D, from the communication hole 212 of the inlet gas conduit 21 to the communication hole 222 of the outlet gas conduit 22.

[0097] exist Figure 7 In the embodiment shown, Figure 7 As shown, the flow path cross-sectional area of the nearby temperature-increasing gas pipe 5C is the same as the flow path cross-sectional area of the remote temperature-increasing gas pipe 5D (within a range of ±5% of the flow path cross-sectional area of the nearby temperature-increasing gas pipe 5C). By providing a throttle orifice (throttle portion) 81, which is smaller than the flow path cross-sectional areas of the nearby temperature-increasing gas pipe 5C and the remote temperature-increasing gas pipe 5D, at the connection C1 between the nearby temperature-increasing gas pipe 5C and the inlet gas duct 21, the opening area 50C of the nearby temperature-increasing gas pipe 5C is smaller than the opening area 50D of the remote temperature-increasing gas pipe 5D.

[0098] exist Figure 7 In the embodiment shown, the throttle hole 81 is formed by an opening hole formed in the throttle plate 8. The throttle plate 8 is arranged at the connection portion C1 between the inlet gas conduit 21 and the nearby heated gas pipe 5C so that the opening hole, i.e., the throttle hole 81, closes a portion of the communication hole 212 of the inlet gas conduit 21. Figure 7 In the illustrated embodiment, the orifice plate 8 is disposed within an internal space 210A formed within the inlet gas conduit 21 and is secured to the inlet gas conduit 21 by welding or the like. When viewed in the direction in which the nearby heated gas pipe 5C extends, the orifice plate 8 has an opening area, i.e., an orifice 81, which is an opening hole of the orifice plate 8, that is, is smaller than the flow path cross-sectional area of the nearby heated gas pipe 5C.

[0099] With this configuration, the orifice 81 reduces pressure loss in the nearby heated gas pipe 5C, facilitating the introduction of exhaust gas from the inlet gas conduit 21 into the distal heated gas pipe 5D. By minimizing the difference in flow rate between the exhaust gas flowing through the nearby heated gas pipe 5C and the distal heated gas pipe 5D, heat energy is evenly transferred from the nearby heated gas pipe 5C and the distal heated gas pipe 5D to the oxidation catalyst device 3. This allows for uniform heating of the entire oxidation catalyst device 3, shortening the catalyst warm-up time required for the oxidation catalyst to function effectively when the oxidation catalyst device 3 is first used.

[0100] In addition, the arrangement of the throttle hole 81 is not limited to Figure 7 The embodiment shown. For example, the orifice plate 8 can be fixed inside the nearby heated gas pipe 5C. The orifice plate 8 can be arranged in the internal space 220A formed within the outlet gas pipe 22 so that its opening, i.e., the orifice 81, blocks a portion of the communication hole 222 of the outlet gas pipe 22, and can be fixed to the outlet gas pipe 22 by welding or the like. The orifice plate 8 can be arranged between either the inlet gas pipe 21 or the outlet gas pipe 22 and the nearby heated gas pipe 5C, and fixed to these components by welding or the like.

[0101] Furthermore, a throttling hole having a flow path cross-sectional area smaller than that of the far-side warming gas piping 5D may be provided in at least a portion of the near-side warming gas piping 5C. The flow path cross-sectional area of the near-side warming gas piping 5C may also be made smaller than that of the far-side warming gas piping 5D. Furthermore, the connecting hole 212 connected to the near-side warming gas piping 5C may be made smaller than the connecting hole 212 connected to the far-side warming gas piping 5D, and the connecting hole 222 connected to the near-side warming gas piping 5C may be made smaller than the connecting hole 222 connected to the far-side warming gas piping 5D. Furthermore, the present invention can also be applied to Figure 4 That is, in Figure 4 In the embodiment shown, a throttling hole can be provided so that the opening area of the heating gas piping 5 whose distance from the inlet 211 to the heating gas inlet is short is smaller than the opening area of the heating gas piping 5 whose distance from the inlet 211 to the heating gas inlet is longer than that of the heating gas piping 5.

[0102] (First Oxidation Catalyst Device Temperature Raising Method)

[0103] The oxidation catalyst device temperature raising method according to some embodiments is a method for raising the temperature of the oxidation catalyst device 3 configured to oxidize the exhaust gas discharged from the internal combustion engine 11 of the internal combustion engine system 1. The oxidation catalyst device 3 includes a plurality of oxidation catalyst elements 31, each of which includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas. Figure 1 As shown, the internal combustion engine 11 includes a dual-fuel engine capable of switching between a first fuel FU1 containing methane in its exhaust gas components and a second fuel FU2 containing no methane in its exhaust gas components. The first fuel FU1 may be, for example, liquefied natural gas. The second fuel FU2 may be, for example, fuel oil such as diesel or marine gas oil.

[0104] In some embodiments, the above-mentioned oxidation catalyst device heating method comprises: a first operating step, during the period when the internal combustion engine 11 is operating with the first fuel FU1 as fuel, the first exhaust gas discharged from the internal combustion engine 11 is introduced into the catalyst housing 4 that accommodates the oxidation catalyst device 3; and a second operating step, during the period when the internal combustion engine 11 is operating with the second fuel FU2 as fuel, the first exhaust gas discharged from the internal combustion engine 11 is introduced into at least one heating gas piping 5, and the at least one heating gas piping 5 is arranged inside the catalyst housing 4 and between a pair of adjacent oxidation catalyst elements 31 among the multiple oxidation catalyst elements 31.

[0105] Figure 1 The solid arrows in represent the flow of the first exhaust gas in the first operation step. Figure 1 The dotted arrows in represent the flow of the first exhaust gas in the second operation step.

[0106] According to the above method, through the first operating step, while the internal combustion engine 11 is operating with the first fuel FU1, exhaust gas exhausted from the internal combustion engine 11 is introduced into the catalyst housing 4, thereby oxidizing methane contained in the exhaust gas by the methane oxidation catalyst. Through the second operating step, while the internal combustion engine 11 is operating with the second fuel FU2, exhaust gas exhausted from the internal combustion engine 11 that does not contain methane can be introduced into the at least one temperature-increasing gas pipe 5. In this case, exhaust gas exhausted from the internal combustion engine 11 that does not require oxidation by the oxidation catalyst device 3 can be used as the temperature-increasing gas for heating the oxidation catalyst device 3, eliminating the need for a separate heater or other device for maintaining the temperature of the oxidation catalyst device 3. This can suppress the increase in size or complexity of the equipment for heating the oxidation catalyst device 3 or the internal combustion engine system 1 incorporating such equipment, thereby reducing the space occupied by such equipment or the internal combustion engine system 1. This embodiment can reduce the space occupied by the equipment for heating the oxidation catalyst device 3 or the internal combustion engine system 1, making it suitable for use in spaces such as ships.

[0107] Furthermore, according to the above method, the at least one heating gas pipe 5 is disposed between a pair of oxidation catalyst elements 31 disposed adjacent to each other within the catalyst housing 4. Therefore, the heat energy of the heating gas flowing through the heating gas pipe 5 can be efficiently transferred to each of the pair of oxidation catalyst elements 31 sandwiching the heating gas pipe 5. This effectively heats the entire oxidation catalyst device 3, shortening the catalyst heating time required for the oxidation catalyst to function properly when the oxidation catalyst device 3 is first used.

[0108] (Exhaust branch line, exhaust return line)

[0109] like Figure 1 As shown, the oxidation catalyst heating system 2 according to some embodiments further includes an exhaust branch line 23 branching from the exhaust line 12 upstream of the catalyst case 4. The plurality of heating gas pipes 5 are configured to introduce exhaust gas through the exhaust branch line 23.

[0110] exist Figure 1In the illustrated embodiment, the oxidation catalyst heating system 2 includes the aforementioned exhaust branch line 23 and an exhaust return line 24 for returning exhaust gas from each of the plurality of heating gas pipes 5 to the exhaust pipe 12 downstream of the catalyst case 4. The upstream end of the exhaust branch line 23 is connected to the branching portion P1 of the first upstream exhaust pipe 12A, and the downstream end is connected to the inlet 211 of the inlet gas conduit 21. The upstream end of the exhaust return line 24 is connected to the outlet 221 of the outlet gas conduit, and the downstream end is connected to the confluence portion P2 of the first downstream exhaust pipe 12B. The first exhaust gas, which is guided to the plurality of heating gas pipes 5 via the exhaust branch line 23, is then guided to the exhaust pipe 12 downstream of the catalyst case 4 via the exhaust return line 24.

[0111] According to the above configuration, the relatively high-temperature first exhaust gas discharged from the internal combustion engine 11 can be used as the above-mentioned heated gas. In this case, the size or complexity of the structure of the oxidation catalyst heating system 2 or the internal combustion engine system 1 including the oxidation catalyst heating system 2 can be suppressed, and the space occupied by the oxidation catalyst heating system 2 or the internal combustion engine system 1 can be reduced.

[0112] (First exhaust path switching device)

[0113] like Figure 1 As shown, an internal combustion engine system 1 according to some embodiments includes: an oxidation catalyst heating system 2 including the oxidation catalyst device 3, a catalyst housing 4, and at least one heating gas pipe 5; and a first exhaust path switching device 7 configured to switch the path of exhaust gas discharged from the internal combustion engine 11. The oxidation catalyst device 3 includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas. The internal combustion engine 11 includes a dual-fuel engine capable of switching between a first fuel FU1 containing methane in the exhaust gas and a second fuel FU2 containing no methane.

[0114] The first exhaust path switching device 7 is configured to guide the first exhaust gas discharged from the internal combustion engine 11 to the catalyst housing 4 while the internal combustion engine 11 is operating with the first fuel FU1 as fuel, and is configured to guide the first exhaust gas discharged from the internal combustion engine 11 to the above-mentioned at least one heated gas piping 5 while the internal combustion engine 11 is operating with the second fuel FU2 as fuel.

[0115] exist Figure 1 In the illustrated embodiment, the first exhaust path switching device 7 includes a first on-off valve 71 provided downstream of the branch portion P1 of the first upstream exhaust line 12A and a second on-off valve 72 provided in the exhaust branch line 23 .

[0116] During the operation of the internal combustion engine 11 using the first fuel FU1 as fuel, the first on-off valve 71 is open and the second on-off valve 72 is closed. During the operation of the internal combustion engine 11 using the second fuel FU2 as fuel, the second on-off valve 72 is open and the first on-off valve 71 is closed. Figure 1 As shown, the first exhaust path switching device 7 may further include a control device (controller) 70 for controlling the opening and closing of the first on-off valve 71 and the second on-off valve 72. Furthermore, in the above-described oxidation catalyst device temperature raising method, the opening and closing of the first on-off valve 71 and the second on-off valve 72 may also be manually changed.

[0117] According to the above configuration, the first exhaust path switching device 7 directs exhaust gas exhausted from the internal combustion engine 11 into the catalyst housing 4 while the internal combustion engine 11 is operating with the first fuel FU1, thereby enabling methane contained in the exhaust gas to be oxidized by the methane oxidation catalyst. The first exhaust path switching device 7 also directs exhaust gas exhausted from the internal combustion engine 11, which does not contain methane, into the at least one heating gas pipe 5 while the internal combustion engine 11 is operating with the second fuel FU2. In this case, exhaust gas exhausted from the internal combustion engine 11 that does not require oxidation by the oxidation catalyst device 3 can be utilized as the heating gas for heating the oxidation catalyst device 3. This prevents the oxidation catalyst heating system 2 or the internal combustion engine system 1 equipped with the oxidation catalyst heating system 2 from becoming larger or more complex, thereby reducing the space occupied by the oxidation catalyst heating system 2 or the internal combustion engine system 1.

[0118] (Second Oxidation Catalyst Device Temperature Raising Method)

[0119] An oxidation catalyst device temperature-raising method according to some embodiments is a method for raising the temperature of an oxidation catalyst device 3 configured to oxidize exhaust gas exhausted from an internal combustion engine 11 of the internal combustion engine system 1. The oxidation catalyst device 3 includes a plurality of oxidation catalyst elements 31, each of which includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas.

[0120] In some embodiments, the above-mentioned oxidation catalyst device heating method has an exhaust gas introduction step, in which, during the period when the above-mentioned internal combustion engine 11 is stopped, a second exhaust gas that does not contain methane in the exhaust components discharged from another internal combustion engine 13 different from the internal combustion engine 11 is introduced into at least one heating gas piping 5, and the at least one heating gas piping 5 is arranged inside the catalyst housing 4 that accommodates the oxidation catalyst device 3, and is arranged between a pair of adjacent oxidation catalyst elements 31 among a plurality of oxidation catalyst elements 31.

[0121] Figure 2 In the embodiment shown, Figure 2As shown, the internal combustion engine 11 and the internal combustion engine 13 include dual-fuel engines capable of switching between a first fuel FU1 containing methane in exhaust gas components and a second fuel FU2 containing no methane in exhaust gas components for operation. Figure 2 The solid arrows in ⊂ indicate the flows of the first exhaust gas and the second exhaust gas during operation of the internal combustion engine 11 and the internal combustion engine 13 using the first fuel FU1 as fuel. Figure 2 The dashed arrows in ∘ indicate the flow of the second exhaust gas during a period in which the internal combustion engine 11 is stopped and the internal combustion engine 13 is operating using the second fuel FU2 as fuel.

[0122] According to the above method, through the exhaust gas introduction step, while the internal combustion engine 11 is stopped, the second exhaust gas, which does not contain methane in its exhaust components, emitted from another internal combustion engine 13, can be introduced into the at least one warming gas pipe 5. In this case, the exhaust gas emitted from the other internal combustion engine 13, which does not require oxidation by the oxidation catalyst device 3, can be utilized as the warming gas for heating the oxidation catalyst device 3. This can suppress the increase in size or complexity of the equipment for heating the oxidation catalyst device 3 or the internal combustion engine system 1 incorporating such equipment, thereby reducing the space occupied by such equipment or the internal combustion engine system 1. This embodiment can reduce the space occupied by the equipment for heating the oxidation catalyst device 3 or the internal combustion engine system 1, making it suitable for use in space-constrained vessels, etc. Furthermore, according to the above method, exhaust gas can be introduced into the at least one warming gas pipe 5 even while the internal combustion engine 11 is stopped, allowing the oxidation catalyst device 3 to be heated by the exhaust gas flowing through the warming gas pipe 5.

[0123] Furthermore, according to the above method, the at least one heating gas pipe 5 is disposed between a pair of oxidation catalyst elements 31 disposed adjacent to each other within the catalyst housing 4. Therefore, the heat energy of the heating gas flowing through the heating gas pipe 5 can be efficiently transferred to each of the pair of oxidation catalyst elements 31 sandwiching the heating gas pipe 5. This effectively heats the entire oxidation catalyst device 3, shortening the catalyst heating time required for the oxidation catalyst to function properly when the oxidation catalyst device 3 is first used.

[0124] like Figure 2 As shown, the oxidation catalyst heating system 2 according to some embodiments further includes other exhaust pipes 14A and 27, which are different from the exhaust pipe 12 and through which the second exhaust gas discharged from the second internal combustion engine 13 flows. Each of the plurality of heating gas pipes 5 is configured to introduce exhaust gas through the other exhaust pipes 14A and 27.

[0125] exist Figure 2In the illustrated embodiment, the oxidation catalyst heating system 2 further includes an oxidation catalyst device 3A, a catalyst housing 4A, a plurality of heating gas pipes 5E, an inlet gas conduit 21C mounted on the catalyst housing 4A, and an outlet gas conduit 22C mounted on the catalyst housing 4A. The oxidation catalyst device 3A, the catalyst housing 4A, the heating gas pipes 5E, the inlet gas conduit 21C, and the outlet gas conduit 22C can have the same structures as the oxidation catalyst device 3, the catalyst housing 4, the heating gas pipes 5, the inlet gas conduit 21, and the outlet gas conduit 22 described above, respectively. The catalyst housing 4A is provided in the second exhaust line 14 to accommodate the oxidation catalyst device 3A and the plurality of heating gas pipes 5E.

[0126] The second exhaust line 14 includes a second upstream exhaust line 14A for guiding the second exhaust gas from the internal combustion engine 13 to the catalyst case 4A, and a second downstream exhaust line 14B for guiding the second exhaust gas from the catalyst case 4A to the downstream side in the flow direction of the second exhaust gas.

[0127] exist Figure 2 In the illustrated embodiment, the oxidation catalyst heating system 2 includes a first exhaust branch line 25 that branches from the second exhaust line 14 upstream of the catalyst housing 4A to guide the second exhaust gas to a plurality of heating gas pipes 5E; and a first exhaust return line 26 for returning the exhaust gas from each of the plurality of heating gas pipes 5E to the exhaust line 14 downstream of the catalyst housing 4A. The upstream end of the first exhaust branch line 25 is connected to the branch point P3 of the second upstream exhaust line 14A, and the downstream end is connected to the inlet gas conduit 21C. The upstream end of the first exhaust return line 26 is connected to the outlet gas conduit 22C, and the downstream end is connected to the confluence point P4 of the second downstream exhaust line 14B. The second exhaust gas, which is guided to the plurality of heating gas pipes 5E via the first exhaust branch line 25, is then guided to the exhaust line 14 downstream of the catalyst housing 4A via the first exhaust return line 26.

[0128] exist Figure 2In the illustrated embodiment, the oxidation catalyst heating system 2 includes a second exhaust branch line 27 that branches from the first exhaust branch line 25 to direct the second exhaust gas to the plurality of heating gas pipes 5; and a second exhaust return line 28 that returns the exhaust gas from each of the plurality of heating gas pipes 5E to the exhaust pipe 14 downstream of the catalyst case 4A. The upstream end of the second exhaust branch line 27 is connected to the branching point P5 of the first exhaust branch line 25, and the downstream end is connected to the inlet gas conduit 21. The upstream end of the second exhaust return line 28 is connected to the outlet gas conduit 22, and the downstream end is connected to the confluence point P6 of the second downstream exhaust pipe 14B. The second exhaust gas, which is directed to the plurality of heating gas pipes 5 via the second exhaust branch line 27, is then directed to the exhaust pipe 14 downstream of the catalyst case 4A via the second exhaust return line 28.

[0129] According to the above configuration, the relatively high-temperature second exhaust gas discharged from the second internal combustion engine 13 can be utilized as the above-mentioned heating gas. In this case, the size and complexity of the oxidation catalyst heating system 2 or the internal combustion engine system 1 equipped with the oxidation catalyst heating system 2 can be suppressed, and the space occupied by the oxidation catalyst heating system 2 or the internal combustion engine system 1 can be reduced. Furthermore, according to the above configuration, even when the internal combustion engine 11 is stopped, the second exhaust gas can be introduced into the at least one heating gas pipe 5, and the oxidation catalyst device 3 can be heated by the second exhaust gas flowing through the heating gas pipe 5.

[0130] In some embodiments, the oxidation catalyst heating system 2 may include a second exhaust branch line in place of the second exhaust branch line 27. The upstream end of this second exhaust branch line is connected to the second downstream exhaust line 14B upstream of the confluence points P4 and P6, and the downstream end is connected to the inlet gas conduit 21. With this configuration, exhaust gas from the second internal combustion engine 13 containing methane can be oxidized by the oxidation catalyst device 3 and then introduced into the at least one heating gas pipe 5. In this case, while the internal combustion engine 11 is stopped, the oxidized exhaust gas from another internal combustion engine (the second internal combustion engine 13) can be used as heating gas. Furthermore, even if the fuel used to operate the second internal combustion engine 13 is either the first fuel containing methane in its exhaust components or the second fuel not containing methane in its exhaust components, the oxidized exhaust gas from the second internal combustion engine 13 can still be used as heating gas.

[0131] like Figure 2As shown, an internal combustion engine system 1 according to some embodiments includes an oxidation catalyst heating system 2 including the oxidation catalyst device 3, 3A, a catalyst housing 4, 4A, and heating gas pipes 5, 5E; and a second exhaust gas path switching device 7A configured to switch the path of the second exhaust gas emitted from the internal combustion engine 13. The oxidation catalyst device 3 includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas. The internal combustion engine 13 includes a dual-fuel engine capable of switching between a first fuel FU1 containing methane in the exhaust gas and a second fuel FU2 containing no methane.

[0132] The second exhaust path switching device 7A is configured to guide the second exhaust gas to the catalyst housing 4A while the internal combustion engine 13 is operating with the first fuel FU1 as fuel, and is configured to guide the second exhaust gas to the warming gas piping 5, 5E while the internal combustion engine 11 is stopped and while the internal combustion engine 13 is operating with the second fuel FU2 as fuel.

[0133] exist Figure 2 In the illustrated embodiment, the second exhaust path switching device 7A includes: a first on-off valve 71A provided in the second upstream exhaust pipe 14A on the downstream side of the branch portion P3; and a second on-off valve 72A provided in the first exhaust branch pipe 25 on the upstream side of the branch portion P5.

[0134] While the internal combustion engine 13 is operating with the first fuel FU1 as fuel, the first on-off valve 71A is open and the second on-off valve 72A is closed. While the internal combustion engine 11 is stopped and the internal combustion engine 13 is operating with the second fuel FU2 as fuel, the second on-off valve 72A is open and the first on-off valve 71A is closed. Figure 2 As shown, the second exhaust path switching device 7A may further include a control device (controller) 70A for controlling the opening and closing of the first on-off valve 71A and the second on-off valve 72A. Furthermore, in the above-described oxidation catalyst device temperature raising method, the opening and closing of the first on-off valve 71A and the second on-off valve 72A may be manually changed.

[0135] According to the above configuration, the second exhaust path switching device 7A allows exhaust gas that does not contain methane among the exhaust components discharged from the other internal combustion engine 13 to be introduced into the at least one warming gas pipe 5 while the other internal combustion engine 13 is operating with the second fuel FU2. In this case, exhaust gas discharged from the other internal combustion engine 13 that does not require oxidation by the oxidation catalyst device 3 can be utilized as the warming gas for heating the oxidation catalyst device 3. This can prevent the oxidation catalyst warming system 2 or the internal combustion engine system 1 equipped with the oxidation catalyst warming system 2 from becoming larger or more complex, and can reduce the space occupied by the oxidation catalyst warming system 2 or the internal combustion engine system 1.

[0136] In this specification, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configurations not only strictly indicate such configurations, but also indicate a state of relative displacement at an angle or distance with a tolerance or a degree that can achieve the same function.

[0137] For example, expressions such as “same,” “equal,” and “homogeneous,” which indicate a state of equality of things, not only indicate a strictly equal state but also indicate a state in which there is a tolerance or a degree of difference to achieve the same function.

[0138] Furthermore, in this specification, expressions indicating shapes such as quadrilaterals and cylinders not only indicate shapes such as quadrilaterals and cylinders in a strict geometric sense, but also indicate shapes including concave and convex portions or chamfered portions as long as the same effect can be obtained.

[0139] Furthermore, in this specification, the expression “including”, “comprising” or “having” one constituent element is not an exclusive expression excluding the presence of other constituent elements.

[0140] The present invention is not limited to the above-described embodiment, and includes additional modifications to the above-described embodiment, or appropriate combinations of these embodiments.

[0141] The contents described in some of the above-mentioned embodiments can be understood, for example, as follows.

[0142] 1) An oxidation catalyst temperature increasing system 2 according to at least one embodiment of the present invention includes:

[0143] an exhaust pipe 12 for the flow of exhaust gas discharged from the internal combustion engine 11;

[0144] a catalyst housing 4 provided on the exhaust pipe 12 and accommodating an oxidation catalyst device 3 including a plurality of oxidation catalyst elements 31 configured to oxidize the exhaust gas; and

[0145] At least one heating gas pipe 5 , through which heating gas for heating the oxidation catalyst device 3 flows, is disposed inside the catalyst housing 4 and between a pair of adjacent oxidation catalyst elements 31 among the plurality of oxidation catalyst elements 31 .

[0146] According to the configuration 1) above, the oxidation catalyst device 3 can be heated while not in use by the heated gas flowing through the at least one heated gas pipe 5. Because the at least one heated gas pipe 5 is disposed between a pair of adjacent oxidation catalyst elements 31 within the catalyst housing 4, the thermal energy of the heated gas flowing through the heated gas pipe 5 can be efficiently transferred to each of the pair of oxidation catalyst elements 31 sandwiching the heated gas pipe 5. This allows the entire oxidation catalyst device 3 to be heated efficiently, shortening the catalyst heating time required for the oxidation catalyst to function properly when the oxidation catalyst device 3 is first used.

[0147] 2) In some embodiments, according to the oxidation catalyst heating system 2 described in 1) above,

[0148] The at least one temperature-increasing gas pipe 5 extends in a direction intersecting with the flow direction (first direction RD1 ) of the exhaust gas flowing inside the catalyst case 4 .

[0149] According to the configuration of 2) above, the at least one heating gas pipe 5 extends in a direction intersecting the flow direction (first direction RD1) of the exhaust gas flowing within the catalyst housing 4. Therefore, the thermal energy of the heating gas flowing through the heating gas pipe 5 can be efficiently transferred to the entire oxidation catalyst device 3 disposed within the catalyst housing 4. As a result, the temperature of the oxidation catalyst device 3 can be effectively increased.

[0150] 3) In some embodiments, according to the oxidation catalyst heating system 2 described in 2) above,

[0151] The at least one heating gas pipe 5 has a rectangular cross-sectional shape having a pair of long sides and a pair of short sides.

[0152] The pair of long side portions 51 and 52 of the temperature-increasing gas pipe 5 , which have the long sides, respectively abut against the pair of oxidation catalyst elements 31 .

[0153] According to the configuration in 3) above, the pair of relatively large long sides 51 and 52 of the at least one heating gas pipe 5 each abut against the oxidation catalyst element 31. Through the pair of long sides 51 and 52 with their large heat transfer areas, the heat energy of the heating gas flowing through the heating gas pipe 5 can be directly and efficiently transferred to each of the oxidation catalyst elements 31 facing the pair of long sides 51 and 52. This effectively increases the temperature of the oxidation catalyst device 3.

[0154] 4) In some embodiments, according to the oxidation catalyst heating system 2 described in 3) above,

[0155] The at least one heating gas pipe 5 includes a plurality of heating gas pipes 5 , which are arranged at intervals in a direction intersecting an extending direction of the heating gas pipes 5 when viewed from a first direction RD1 which is a flow direction of the exhaust gas flowing inside the catalyst housing 4.

[0156] The oxidation catalyst heating system 2 further includes a plurality of partitions 6. When viewed from the first direction RD1, one end of each of the plurality of partitions 6 is connected to one of a pair of heating gas pipes 5 arranged adjacent to each other in a direction intersecting the extending direction of the heating gas pipe 5, and the other ends of each of the plurality of partitions 6 are connected to the other heating gas pipe. The plurality of partitions 6 are arranged at intervals in the extending direction of the heating gas pipe 5.

[0157] Each of the plurality of oxidation catalyst elements 31 is housed in a space defined by the pair of temperature-increasing gas pipes 5 and the plurality of partition plates 6 .

[0158] According to the configuration of (4) above, the oxidation catalyst element 31 can be housed in each of the spaces defined by the pair of heating gas pipes 5 and the plurality of partitions 6, thereby facilitating positioning of the oxidation catalyst element 31. Furthermore, within the oxidation catalyst element 31 housed in the spaces, the thermal energy of the heating gas flowing through the pair of heating gas pipes 5 is transferred via the pair of heating gas pipes 5 and the plurality of partitions 6 surrounding the oxidation catalyst element 31. This effectively increases the temperature of the entire oxidation catalyst element 31 housed in the spaces.

[0159] 5) In some embodiments, the oxidation catalyst heating system 2 according to any one of 1) to 3) above, wherein:

[0160] The exhaust branch line 23 is further provided. The exhaust branch line 23 branches off from the exhaust line 12 upstream of the catalyst case 4.

[0161] The at least one temperature-increasing gas pipe 5 is configured to introduce the exhaust gas via the exhaust branch line 23 .

[0162] According to the configuration of 5) above, the relatively high-temperature exhaust gas discharged from the internal combustion engine 11 can be utilized as the above-mentioned heated gas. In this case, the size or complexity of the structure of the oxidation catalyst heating system 2 or the internal combustion engine system 1 including the oxidation catalyst heating system 2 can be suppressed, and the space occupied by the oxidation catalyst heating system 2 or the internal combustion engine system 1 can be reduced.

[0163] 6) In some embodiments, according to the oxidation catalyst heating system 2 described in any one of 1) to 3) above,

[0164] The exhaust pipe 14A and 27 are different from the exhaust pipe 12 and are used to pass exhaust gas discharged from an internal combustion engine 13 different from the internal combustion engine 11.

[0165] The at least one temperature-increasing gas pipe 5 is configured to introduce the exhaust gas via the other exhaust gas lines 14A and 27 .

[0166] According to the configuration of section 6), relatively high-temperature exhaust gas from another internal combustion engine 13 can be utilized as the heating gas. In this case, the size and complexity of the oxidation catalyst heating system 2 or the internal combustion engine system 1 equipped with it can be suppressed, and the space occupied by the oxidation catalyst heating system 2 or the internal combustion engine system 1 can be reduced. Furthermore, according to the configuration of section 6), exhaust gas can be introduced into the at least one heating gas pipe 5 even when the internal combustion engine 11 is stopped, and the oxidation catalyst device 3 can be heated by the exhaust gas flowing through the heating gas pipe 5.

[0167] 7) In some embodiments, according to the oxidation catalyst heating system 2 described in any one of 2) to 4) above,

[0168] The at least one heating gas pipe 5 comprises:

[0169] at least one first temperature-increasing gas pipe 5A through which the temperature-increasing gas flows from one side to the other side in the extending direction of the temperature-increasing gas pipe 5 ; and

[0170] at least one second temperature-increasing gas pipe 5B for allowing the temperature-increasing gas to flow from the other side toward the one side in the extending direction of the temperature-increasing gas pipe 5 .

[0171] According to the configuration of 7) above, by aligning the exhaust gas flowing through the at least one first heating gas pipe 5A and the exhaust gas flowing through the at least one second heating gas pipe 5B in opposite directions, it is possible to suppress the heat transfer from the heating gas flowing through the plurality of heating gas pipes 5A and 5B to the oxidation catalyst device 3 from being offset in the direction in which the heating gas pipes 5 extend. This allows the entire oxidation catalyst device 3 to be heated uniformly, shortening the catalyst heating time required for the oxidation catalyst to exhibit its performance when the oxidation catalyst device 3 is first used.

[0172] 8) In some embodiments, the oxidation catalyst heating system 2 according to any one of 1) to 7) above, wherein:

[0173] The at least one heating gas pipe 5 includes a plurality of heating gas pipes 5 , and a heating gas inlet port for introducing the heating gas from the outside into the heating gas pipe 5 is connected to a common inlet gas conduit 21 .

[0174] According to the configuration of item 8) above, by connecting the multiple heating gas pipes 5 to the common inlet gas conduit 21, it is possible to minimize differences in the temperature or flow rate of the exhaust gas introduced from the inlet gas conduit 21 into the multiple heating gas pipes 5. By minimizing differences in the temperature or flow rate of the exhaust gas introduced into the multiple heating gas pipes 5, the heating gas flowing through the multiple heating gas pipes 5 uniformly transfers thermal energy to the oxidation catalyst device 3. This allows the entire oxidation catalyst device 3 to be uniformly heated, shortening the catalyst heating time required for the oxidation catalyst to exhibit its performance when the oxidation catalyst device 3 is first used.

[0175] 9) In some embodiments, according to the oxidation catalyst heating system 2 described in 8) above,

[0176] The inlet gas conduit 21 has an inlet port 211 for introducing the heated gas into the inlet gas conduit 21 .

[0177] The plurality of heating gas pipes 5 connected to the inlet gas conduit 21 include:

[0178] Nearby side heating gas piping 5C; and

[0179] The remote side heating gas pipe 5D is connected to the inlet gas conduit 21 at a position farther from the inlet port 211 than the nearby side heating gas pipe 5C.

[0180] A throttling hole 81 having an opening area smaller than that of the distal side heating gas pipe 5D is provided on either the proximal side heating gas pipe 5C or the connection portion C1 between the proximal side heating gas pipe 5C and the inlet gas conduit 21 or the connection portion C2 between the proximal side heating gas pipe 5C and the outlet gas conduit 22.

[0181] According to the configuration in item 9), the throttle hole 81 reduces the pressure loss in the near-side heated gas pipe 5C, facilitating the introduction of exhaust gas from the inlet gas conduit 21 into the far-side heated gas pipe 5D. By minimizing the difference in flow rate between the exhaust gas flowing through the near-side heated gas pipe 5C and the far-side heated gas pipe 5D, heat energy is evenly transferred from the near-side heated gas pipe 5C and the far-side heated gas pipe 5D to the oxidation catalyst device 3. This allows for a uniform temperature increase across the entire oxidation catalyst device 3, shortening the catalyst warm-up time required for the oxidation catalyst to function effectively when the oxidation catalyst device 3 is first used.

[0182] 10) In some embodiments, the oxidation catalyst heating system 2 according to any one of 1) to 9) above, wherein:

[0183] The oxidation catalyst device 3 includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas.

[0184] According to the configuration of 10), the methane oxidation catalyst (oxidation catalyst device 3) needs to be maintained at a relatively high temperature to maximize its performance. However, the heated gas flowing through the at least one heated gas pipe 5 can increase the temperature of the methane oxidation catalyst. This shortens the catalyst heating time required for the methane oxidation catalyst to exhibit its performance when the oxidation catalyst device 3 is first used.

[0185] 11) An internal combustion engine system 1 according to at least one embodiment of the present invention includes:

[0186] The oxidation catalyst heating system 2 described in 5) above;

[0187] the internal combustion engine 11; and

[0188] The first exhaust path switching device 7 is configured to switch the path of the exhaust gas discharged from the internal combustion engine 11. In the internal combustion engine system 1,

[0189] The oxidation catalyst device 3 includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas.

[0190] The internal combustion engine 11 includes a dual-fuel engine capable of switching between a first fuel FU1 containing methane in the exhaust gas component and a second fuel FU2 containing no methane in the exhaust gas component.

[0191] The first exhaust path switching device 7 is configured to direct the exhaust gas discharged from the internal combustion engine 11 to the catalyst housing 4 while the internal combustion engine 11 is operating with the first fuel FU1 as fuel, and is configured to direct the exhaust gas discharged from the internal combustion engine 11 to the at least one heated gas piping 5 while the internal combustion engine 11 is operating with the second fuel FU2 as fuel.

[0192] According to the configuration of item 11), the first exhaust path switching device 7 directs exhaust gas exhausted from the internal combustion engine 11 into the catalyst housing 4 while the internal combustion engine 11 is operating with the first fuel FU1, thereby enabling methane contained in the exhaust gas to be oxidized by the methane oxidation catalyst. The first exhaust path switching device 7 also directs exhaust gas exhausted from the internal combustion engine 11, which does not contain methane, into the at least one temperature-increasing gas pipe 5 while the internal combustion engine 11 is operating with the second fuel FU2. In this case, exhaust gas exhausted from the internal combustion engine 11 that does not require oxidation by the oxidation catalyst device 3 can be utilized as the temperature-increasing gas for increasing the temperature of the oxidation catalyst device 3. This prevents the oxidation catalyst temperature-increasing system 2 or the internal combustion engine system 1 equipped with the oxidation catalyst temperature-increasing system 2 from increasing in size or complexity, thereby reducing the space occupied by the oxidation catalyst temperature-increasing system 2 or the internal combustion engine system 1.

[0193] 12) An internal combustion engine system 1 according to at least one embodiment of the present invention includes:

[0194] The oxidation catalyst heating system 2 described in 6) above;

[0195] the internal combustion engine 11;

[0196] the other internal combustion engine 13; and

[0197] The second exhaust path switching device 7A is configured to switch the path of the exhaust gas discharged from the other internal combustion engine 13. In the internal combustion engine system 1,

[0198] The other internal combustion engine 13 includes a dual-fuel engine capable of switching between a first fuel FU1 containing methane in the exhaust gas component and a second fuel FU2 containing no methane in the exhaust gas component.

[0199] The second exhaust path switching device 7A is configured to guide the exhaust gas exhausted from the other internal combustion engine 13 to the at least one temperature-increasing gas pipe 5 while the other internal combustion engine 13 is operating with the second fuel FU2 .

[0200] According to the configuration of 12) above, the second exhaust path switching device 7A allows exhaust gas, which does not contain methane among the exhaust components discharged from the other internal combustion engine 13, to be introduced into the at least one warming gas pipe 5 while the other internal combustion engine 13 is operating with the second fuel FU2. In this case, exhaust gas discharged from the other internal combustion engine 13, which does not require oxidation by the oxidation catalyst device 3, can be utilized as the warming gas for heating the oxidation catalyst device 3. This prevents the oxidation catalyst warming system 2 or the internal combustion engine system 1 equipped with the oxidation catalyst warming system 2 from becoming larger or more complex, and reduces the space occupied by the oxidation catalyst warming system 2 or the internal combustion engine system 1.

[0201] 13) An oxidation catalyst device temperature-raising method according to at least one embodiment of the present invention is for raising the temperature of an oxidation catalyst device 3 configured to oxidize exhaust gas discharged from an internal combustion engine 11, wherein:

[0202] The oxidation catalyst device 3 includes a plurality of oxidation catalyst elements 31 , each of which includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas.

[0203] The internal combustion engine 11 includes a dual-fuel engine capable of switching between a first fuel FU1 containing methane in the exhaust gas component and a second fuel FU2 containing no methane in the exhaust gas component.

[0204] The oxidation catalyst device temperature raising method comprises:

[0205] a first operation step of introducing the exhaust gas discharged from the internal combustion engine 11 into the catalyst housing 4 accommodating the oxidation catalyst device 3 while the internal combustion engine 11 is operating with the first fuel FU1; and

[0206] The second operating step is to introduce the exhaust gas discharged from the internal combustion engine 11 into at least one heated gas pipe 5 during the operation of the internal combustion engine 11 using the second fuel FU2 as fuel. The at least one heated gas pipe 5 is arranged inside the catalyst housing 4 and is arranged between a pair of adjacent oxidation catalyst elements 31 among the multiple oxidation catalyst elements 31.

[0207] According to the method in 13) above, the first operating step allows exhaust gas exhausted from the internal combustion engine 11 to be introduced into the catalyst housing 4 while the internal combustion engine 11 is operating with the first fuel FU1, thereby oxidizing methane contained in the exhaust gas by the methane oxidation catalyst. The second operating step allows exhaust gas exhausted from the internal combustion engine 11, which does not contain methane, to be introduced into the at least one temperature-increasing gas pipe 5 while the internal combustion engine 11 is operating with the second fuel FU2. In this case, exhaust gas exhausted from the internal combustion engine 11 that does not require oxidation by the oxidation catalyst device 3 can be utilized as the temperature-increasing gas for increasing the temperature of the oxidation catalyst device 3. This can prevent the size and complexity of the equipment used to increase the temperature of the oxidation catalyst device 3 or the internal combustion engine system 1 incorporating such equipment from increasing the temperature, thereby reducing the space occupied by such equipment or the internal combustion engine system 1.

[0208] Furthermore, according to the method 13) above, the at least one heating gas pipe 5 is disposed between a pair of adjacent oxidation catalyst elements 31 within the catalyst housing 4. Therefore, the thermal energy of the heating gas flowing through the heating gas pipe 5 can be efficiently transferred to each of the pair of oxidation catalyst elements 31 sandwiching the heating gas pipe 5. This effectively heats the entire oxidation catalyst device 3, shortening the catalyst heating time required for the oxidation catalyst to exhibit its performance when the oxidation catalyst device 3 is first used.

[0209] 14) An oxidation catalyst device temperature-raising method according to at least one embodiment of the present invention is for raising the temperature of an oxidation catalyst device 3 configured to oxidize exhaust gas discharged from an internal combustion engine 11, wherein:

[0210] The oxidation catalyst device 3 includes a plurality of oxidation catalyst elements 31 , each of which includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas.

[0211] The oxidation catalyst device heating method includes an exhaust gas introduction step, in which, during the period when the internal combustion engine 11 is stopped, exhaust gas that does not contain methane in the exhaust components discharged from another internal combustion engine 13 different from the internal combustion engine 11 is introduced into at least one heating gas piping 5, and the at least one heating gas piping 5 is arranged inside the catalyst housing 4 that accommodates the oxidation catalyst device 3, and is arranged between a pair of adjacent oxidation catalyst elements 31 among the multiple oxidation catalyst elements 31.

[0212] According to the method in 14), the exhaust gas introduction step allows exhaust gas, which does not contain methane in its exhaust components, emitted from another internal combustion engine 13 to be introduced into the at least one warming gas pipe 5 while the internal combustion engine 11 is stopped. In this case, exhaust gas emitted from another internal combustion engine 13, which does not require oxidation by the oxidation catalyst device 3, can be used as the warming gas for heating the oxidation catalyst device 3. This prevents the size and complexity of the equipment used to heat the oxidation catalyst device 3 or the internal combustion engine system 1 incorporating such equipment from increasing its temperature, thereby reducing the space occupied by such equipment or the internal combustion engine system 1. Furthermore, according to the method in 14), exhaust gas can be introduced into the at least one warming gas pipe 5 even while the internal combustion engine 11 is stopped, allowing the temperature of the oxidation catalyst device 3 to be raised by the exhaust gas flowing through the warming gas pipe 5.

[0213] Furthermore, according to the method 14), the at least one heating gas pipe 5 is disposed between a pair of adjacent oxidation catalyst elements 31 within the catalyst housing 4. Therefore, the thermal energy of the heating gas flowing through the heating gas pipe 5 can be efficiently transferred to each of the pair of oxidation catalyst elements 31 sandwiching the heating gas pipe 5. This effectively heats the entire oxidation catalyst device 3, shortening the catalyst heating time required for the oxidation catalyst to exhibit its performance when the oxidation catalyst device 3 is first used.

[0214] Explanation of symbols

[0215] 1-Internal combustion engine system, 2-Oxidation catalyst heating system, 3, 3A-Oxidation catalyst device, 4, 4A-Catalyst housing, 5, 5E-Heating gas piping, 5A-1st heating gas piping, 5B-2nd heating gas piping, 5C-Nearby side heating gas piping, 5D-Remote side heating gas piping, 6-Partition, 7-1st exhaust path switching device, 7A-2nd exhaust path switching device, 8-Throttle orifice, 11, 13-Internal combustion engine, 12, 14-Exhaust pipe, 12A-1st upstream exhaust pipe, 12B-1st downstream exhaust pipe, 14A-2nd upstream exhaust pipe, 14B-2nd downstream exhaust pipe, 21, 21C-Inlet gas conduit, 21A-1st inlet gas conduit, 21B-2nd inlet Inlet gas conduit, 22, 22C-outlet gas conduit, 22A-1st outlet gas conduit, 22B-2nd outlet gas conduit, 23, 25, 27-exhaust branch pipe, 24, 26, 28-exhaust return pipe, 31-oxidation catalyst element, 40-1st internal space, 41-shell main body, 42-1st exhaust inlet, 43-1st exhaust outlet, 44-1st gas conduit main body, 45, 47-partition wall, 46-2nd gas conduit main body, 51, 52-long side, 71, 71A-1st on-off valve, 72, 72A-2nd on-off valve, 81-throttle hole, 400-space, FU1-1st fuel, FU2-2nd fuel, P1, P3, P5-branching part, P2, P4, P6-merging part.

Claims

1. An oxidation catalyst heating system comprising: an exhaust line for the flow of exhaust gas from the internal combustion engine; a catalyst housing provided in the exhaust pipe and accommodating an oxidation catalyst device including a plurality of oxidation catalyst elements configured to oxidize the exhaust gas; and At least one temperature-increasing gas pipe flows a temperature-increasing gas for increasing the temperature of the oxidation catalyst device, and is disposed inside the catalyst housing and between a pair of adjacent oxidation catalyst elements among the plurality of oxidation catalyst elements.

2. The oxidation catalyst heating system according to claim 1, wherein: The at least one temperature-increasing gas pipe extends in a direction intersecting with a flow direction of the exhaust gas flowing inside the catalyst case.

3. The oxidation catalyst heating system according to claim 2, wherein: The at least one temperature-increasing gas pipe has a rectangular cross-sectional shape having a pair of long sides and a pair of short sides. A pair of long side portions of the temperature-increasing gas pipe having the long sides are in contact with the pair of oxidation catalyst elements, respectively.

4. The oxidation catalyst heating system according to claim 3, wherein: The at least one heating gas pipe includes a plurality of heating gas pipes, the plurality of heating gas pipes being arranged at intervals in a direction intersecting an extending direction of the heating gas pipes when viewed from a first direction which is a flow direction of the exhaust gas flowing inside the catalyst housing. The oxidation catalyst temperature increasing system further includes a plurality of partitions, when viewed from the first direction, One end of each of the plurality of partitions is connected to one of a pair of heating gas pipes arranged adjacent to each other in a direction intersecting the extending direction of the heating gas pipe, and the other ends of each of the plurality of partitions are connected to the other heating gas pipe, and the plurality of partitions are arranged at intervals in the extending direction of the heating gas pipe. Each of the plurality of oxidation catalyst elements is housed in a space defined by the pair of temperature-increasing gas pipes and the plurality of partition plates.

5. The oxidation catalyst heating system according to any one of claims 1 to 4, wherein: An exhaust branch line is further provided, the exhaust branch line branching from the exhaust line on the upstream side of the catalyst case, The at least one temperature-increasing gas pipe is configured to introduce the exhaust gas through the exhaust branch line.

6. The oxidation catalyst heating system according to any one of claims 1 to 4, wherein: further comprising another exhaust line different from the exhaust line, the exhaust line different from the exhaust line being a passage for exhaust gas discharged from another internal combustion engine different from the internal combustion engine; The at least one temperature-increasing gas pipe is configured to introduce the exhaust gas via the other exhaust gas line.

7. The oxidation catalyst heating system according to any one of claims 2 to 4, wherein: The at least one heating gas pipe comprises: at least one first temperature-increasing gas pipe for allowing the temperature-increasing gas to flow from one side to the other side in the extending direction of the temperature-increasing gas pipe; and and at least one second temperature-increasing gas pipe for allowing the temperature-increasing gas to flow from the other side toward the one side in the extending direction of the temperature-increasing gas pipe.

8. The oxidation catalyst heating system according to any one of claims 1 to 4, wherein: The at least one heating gas pipe includes a plurality of heating gas pipes, wherein a heating gas inlet port for introducing the heating gas from the outside into the heating gas pipe is connected to a common inlet gas conduit.

9. The oxidation catalyst heating system according to claim 8, wherein: The inlet gas conduit has an inlet for introducing the heated gas into the interior of the inlet gas conduit. The plurality of heating gas pipes connected to the inlet gas conduit include: nearby heating gas piping; and a remote-side heating gas pipe connected to the inlet gas conduit at a position farther from the inlet port than the nearby-side heating gas pipe, A throttle hole having an opening area smaller than that of the distal side heating gas pipe is provided on either the proximal side heating gas pipe or the connection between the proximal side heating gas pipe and the inlet gas conduit or the connection between the proximal side heating gas pipe and the outlet gas conduit.

10. The oxidation catalyst heating system according to any one of claims 1 to 4, wherein: The oxidation catalyst device includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas.

11. An internal combustion engine system comprising: The oxidation catalyst heating system according to claim 5; the internal combustion engine; and The first exhaust path switching device is configured to switch the path of the exhaust gas discharged from the internal combustion engine. In the internal combustion engine system, The oxidation catalyst device includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas. The internal combustion engine includes a dual-fuel engine capable of switching between a first fuel containing methane in the exhaust gas component and a second fuel containing no methane in the exhaust gas component. The first exhaust path switching device is configured to guide the exhaust gas exhausted from the internal combustion engine to the catalyst housing while the internal combustion engine is operating with the first fuel as fuel, and is configured to guide the exhaust gas exhausted from the internal combustion engine to the at least one heated gas piping while the internal combustion engine is operating with the second fuel as fuel.

12. An internal combustion engine system comprising: The oxidation catalyst heating system according to claim 6; said internal combustion engine; said other internal combustion engines; and The second exhaust path switching device is configured to switch the path of the exhaust gas discharged from the other internal combustion engine, wherein the internal combustion engine system The other internal combustion engine includes a dual-fuel engine capable of switching between a first fuel containing methane in the exhaust gas component and a second fuel containing no methane in the exhaust gas component. The second exhaust path switching device is configured to guide the exhaust gas exhausted from the other internal combustion engine to the at least one temperature-increased gas pipe while the other internal combustion engine is operating with the second fuel.

13. A method for increasing the temperature of an oxidation catalyst device configured to oxidize exhaust gas discharged from an internal combustion engine, wherein: The oxidation catalyst device includes a plurality of oxidation catalyst elements, each of which includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas. The internal combustion engine includes a dual-fuel engine capable of switching between a first fuel containing methane in the exhaust gas component and a second fuel containing no methane in the exhaust gas component. The oxidation catalyst device temperature raising method comprises: a first operating step of introducing the exhaust gas exhausted from the internal combustion engine into a catalyst case accommodating the oxidation catalyst device while the internal combustion engine is operating using the first fuel; and The second operating step is to introduce the exhaust gas discharged from the internal combustion engine into at least one heated gas piping while the internal combustion engine is operating with the second fuel as fuel. The at least one heated gas piping is arranged inside the catalyst housing and between a pair of adjacent oxidation catalyst elements among the multiple oxidation catalyst elements.

14. A method for increasing the temperature of an oxidation catalyst device configured to oxidize exhaust gas discharged from an internal combustion engine, wherein: The oxidation catalyst device includes a plurality of oxidation catalyst elements, each of which includes a methane oxidation catalyst configured to oxidize methane contained in the exhaust gas. The oxidation catalyst device heating method includes an exhaust gas introduction step, in which, during the period when the internal combustion engine is stopped, exhaust gas that does not contain methane in the exhaust components discharged from another internal combustion engine different from the internal combustion engine is introduced into at least one heating gas piping, and the at least one heating gas piping is arranged inside the catalyst housing accommodating the oxidation catalyst device and is arranged between a pair of adjacent oxidation catalyst elements among the multiple oxidation catalyst elements.

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