Engine equipment and cogeneration system

Abstract

To provide an engine device and cogeneration system that are less prone to low-cycle fatigue. [Solution] The engine device 1 comprises a catalyst case 3 and a cover member 31. The catalyst case 3 houses the catalyst 30 and allows exhaust gas discharged from the engine body to pass through it. The cover member 31 is positioned around the catalyst case 3. The cover member 31 forms an air passage R1 between itself and the catalyst case 3 for passing cooling air.

Description

Technical Field

[0001] The present disclosure relates to an engine device provided with a catalyst that allows exhaust gas to pass therethrough and a cogeneration system. Background Art

[0002] As a related art, there is known an engine device of a type used in cogeneration systems and the like, which is configured to perform high-load operation for a long time (see, for example, Patent Document 1). An engine device according to the related art includes an engine body (gas engine), a catalyst (three-way catalyst), and a heat exchanger (exhaust gas cooler). The catalyst removes nitrogen oxides (NO X x), hydrocarbons (HC) and carbon monoxide (CO) from exhaust gas.

[0003] In the engine device according to the related art, an exhaust manifold of the engine body is connected to the catalyst, and the exhaust gas, from which nitrogen oxides have been removed after passing through the catalyst, passes through a turbine portion of a supercharger, is introduced into the heat exchanger, and is discharged through an exhaust discharge pipe. That is, since the exhaust gas discharged from the engine body passes through the catalyst upstream of the heat exchanger, nitrogen oxides have been removed when the exhaust gas reaches the heat exchanger. Accordingly, nitric acid is less likely to be generated even by condensation caused by cooling of the heat exchanger, and corrosion of exhaust system piping such as the exhaust discharge pipe is less likely to occur. Prior Art Documents Patent Documents

[0004] Patent Document 1 Japanese Unexamined Patent Application Publication No. 10-131742 Summary of the Invention Problems to be Solved by the Invention

[0005] Incidentally, in engine systems with the configuration described above, high-temperature exhaust gases pass through the catalytic converter case, which houses the catalytic converter, and the catalytic converter case itself can become very hot (for example, over 600°C). Under such high-temperature conditions, creep deformation can occur in the catalytic converter case. If creep deformation occurs in the catalytic converter case, and then the temperature of the catalytic converter case decreases after the engine is stopped, excessive tensile stress may be generated at the joints between the catalytic converter case and the piping due to thermal contraction, potentially leading to low-cycle fatigue.

[0006] The purpose of this disclosure is to provide an engine device and a cogeneration system that are less prone to low-cycle fatigue. [Means for solving the problem]

[0007] An engine device according to one aspect of the present disclosure comprises a catalyst case and a cover member. The catalyst case houses a catalyst and allows exhaust gas discharged from the engine body to pass through it. The cover member is positioned around the catalyst case. The cover member forms an air passage between itself and the catalyst case for passing cooling air.

[0008] A cogeneration system according to another aspect of the present disclosure comprises the engine unit, a power generation unit, and a heat exchanger. The power generation unit is driven by the engine unit to generate electricity. The heat exchanger extracts heat generated by the engine unit. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide an engine device and a cogeneration system that are less prone to low-cycle fatigue. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a system diagram showing the schematic configuration of a cogeneration system according to Embodiment 1. [Figure 2] Figure 2 is a schematic perspective view of the main components of the cogeneration system according to Embodiment 1. [Figure 3] Figure 3 is a schematic perspective view of the main components of the cogeneration system according to Embodiment 1. [Figure 4] Figure 4 is a schematic cross-sectional view of the main part of the cogeneration system according to Embodiment 1. [Figure 5] Figure 5 is a schematic exploded perspective view of the main components of the cogeneration system according to Embodiment 1. [Figure 6] Figure 6 is a schematic perspective view of the main components of the cogeneration system according to Embodiment 1. [Figure 7] Figure 7 is a schematic cross-sectional view of the main part of the cogeneration system according to Embodiment 1. [Figure 8] Figure 8 is a schematic side view of the main components of the cogeneration system according to Embodiment 1. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described below with reference to the attached drawings. The following embodiments are examples that embody this disclosure and are not intended to limit the technical scope of this disclosure. The drawings referenced in this disclosure are all schematic diagrams, and the ratios of the size and thickness of each component in the drawings do not necessarily reflect the actual dimensional ratios.

[0012] (Embodiment 1) [1] Overall structure First, the overall configuration of the cogeneration system 10 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 schematically shows the configuration of each part of the cogeneration system 10.

[0013] As shown in Figure 1, the cogeneration system 10 according to this embodiment includes an engine unit 1 including an engine body 2, a power generation device 61, and a heat exchanger 62. The power generation device 61 is a device that generates electricity when driven by the engine body 2. The heat exchanger 62 is a device that extracts heat generated by the engine body 2.

[0014] In summary, the cogeneration system 10 is a system that generates and outputs electric power (electrical energy) and heat (thermal energy). In the present embodiment, the cogeneration system 10 is a stationary device used while installed in a fixed position.

[0015] In addition to an engine body 2, the engine device 1 further includes a catalyst case 3 that houses a catalyst 30, and the like. The "engine" referred to herein is a heat engine that burns fuel to generate mechanical energy (power), and includes an internal combustion engine which is a prime mover in which fuel combustion is performed inside the engine, and thermal energy is converted into mechanical energy using combustion gas as working gas. That is, the engine body 2 generates power (mechanical energy) using supplied fuel.

[0016] The engine body 2 according to the present embodiment is a reciprocating engine that converts reciprocating motion of a piston into rotational motion and outputs rotational force as power. Particularly in the present embodiment, a gas engine that uses gas as fuel will be described as an example of the engine body 2.

[0017] The engine body 2 is arranged in an attitude such that a rotation axis Ax1 of a crankshaft (see Figure 2) is oriented in a substantially horizontal direction. In the present embodiment, for convenience of description, as shown in Figure 2, the direction along the rotation axis Ax1 of the crankshaft is defined as output shaft direction D1. Further, the direction along the vertical direction when the cogeneration system 10 is installed at a fixed position is defined as vertical direction D2, and the direction orthogonal to both the output shaft direction D1 and the vertical direction D2 is defined as width direction D3. Here, one side in the output shaft direction D1 is defined as "front" and the other is defined as "rear", and the side of the crankshaft where a flywheel 21 (see Figure 2) is disposed is defined as the rear. Similarly, one side in the width direction D3 is defined as "left" and the other is defined as "right".

[0018] In other words, each direction used in the present embodiment is a direction defined with reference to the rotation axis Ax1 of the crankshaft. However, none of these directions is intended to limit the direction of use (direction at the time of installation) of the cogeneration system 10.

[0019] In the engine body 2, the rotational force of the crankshaft serving as an engine output shaft is extracted as output. A power generator 61 is connected to the crankshaft either indirectly via a reduction gear or the like, or directly. When the engine body 2 is driven and the crankshaft rotates about the rotation axis Ax1, the power generator 61 is driven.

[0020] Further, the engine body 2 is provided with an intake manifold for distributing and supplying air (supply air) from the outside of the engine body 2 to the inside of the engine body (combustion chambers of respective cylinders). Furthermore, the engine body 2 is provided with an exhaust manifold 22 (see FIG. 3) for collecting exhaust gas generated by combustion in the combustion chambers of the respective cylinders and discharging the same to the outside of the engine body 2.

[0021] The exhaust manifold 22 extends in the output shaft direction D1 and is connected to a plurality of exhaust ports formed in the engine body 2. Accordingly, exhaust gas from the plurality of exhaust ports is collected into the exhaust manifold 22. In other words, the exhaust manifold 22 communicates with the combustion chamber of each cylinder through the exhaust port.

[0022] Further, main components constituting the engine body 2 are made of, for example, metallic materials such as aluminum alloy and cast iron. These main components have desired durability (including rigidity, wear resistance and the like) and relatively excellent thermal conductivity.

[0023] The catalyst 30 is housed in the catalyst case 3. The catalyst case 3 is inserted into the exhaust path 4 (see Figure 1). The exhaust path 4 is connected to the exhaust manifold 22 and is the path through which exhaust gas discharged from the engine body 2 passes. As a result, the exhaust gas passing through the exhaust path 4 passes through the catalyst case 3. At this time, the exhaust gas passes through the catalyst 30 housed in the catalyst case 3, and the catalyst 30 removes nitrogen oxides (NOx) from the exhaust gas. X ), hydrocarbons (HC) and carbon monoxide (CO) are reduced.

[0024] The heat exchanger 62 is inserted into the exhaust path 4 and is a device that recovers heat from the exhaust (waste heat from the engine body 2) by passing the exhaust through it. Specifically, the heat exchanger 62 functions as an exhaust cooler that cools the exhaust by transferring heat from the exhaust to the refrigerant through heat exchange between the refrigerant (heat transfer medium) and the exhaust. In this way, the heat exchanger 62 is able to extract heat from the exhaust.

[0025] In this embodiment, the heat exchanger 62 is inserted downstream of the catalyst case 3 in the exhaust flow direction of the exhaust path 4. As shown in Figure 1, the exhaust path 4 has a first path 41, a second path 42, and a third path 43. The first path 41 connects the engine body 2 and the catalyst case 3, and the second path 42 connects the catalyst case 3 and the heat exchanger 62. The third path 43 is connected to the output side (downstream side in the exhaust flow direction) of the heat exchanger 62 and functions as an exhaust discharge pipe.

[0026] As a result, the exhaust gas discharged from the engine body 2 passes through the catalyst 30 upstream of the heat exchanger 62, so nitrogen oxides are reduced by the time they reach the heat exchanger 62. Therefore, even if the exhaust gas condenses due to cooling in the heat exchanger 62, nitric acid is less likely to be generated, and corrosion of exhaust system piping such as the third path 43 is less likely to occur.

[0027] Furthermore, the engine unit 1 is further equipped with a fuel supply system, a control unit, an exhaust gas recirculation system, and a supercharger, etc. However, these are not essential components of the engine unit 1 and can be omitted as appropriate.

[0028] The fuel supply system injects fuel into the engine body 2 through the fuel supply passage. The control unit outputs control signals (electrical signals) to the engine body 2 and the fuel supply system, etc., and controls the engine body 2 and the fuel supply system, etc. The exhaust gas recirculation system is a device that recirculates at least a portion of the exhaust gas discharged from the engine body 2 as EGR (Exhaust Gas Recirculation) gas from the exhaust port to the intake port of the engine body 2. The supercharger has a compressor located on the intake path for taking air into the intake manifold, and a turbine located on the exhaust path 4 (see Figure 1) connected to the exhaust manifold 22.

[0029] According to the above configuration, when the engine body 2 is driven, the air supplied to each cylinder from the intake manifold is compressed by the sliding of the piston, and at an appropriate timing, the fuel supplied to the combustion chamber from the fuel supply device is burned. The piston reciprocates within the cylinder due to the expansion force obtained from the combustion occurring in the combustion chamber, and the reciprocating motion of the piston is converted into rotational motion of the crankshaft via the connecting rod. As a result, the engine body 2 outputs the rotational force of the crankshaft as power (mechanical energy).

[0030] When the engine body 2 is driven, the exhaust gas generated in the engine body 2 is pushed out of the cylinder by the movement of the piston, collected in the exhaust manifold 22 through the exhaust port, and then discharged to the outside of the engine body 2 through the exhaust path 4. At this time, the exhaust gas passes through the catalytic converter case 3 (including the catalytic converter 30) and the heat exchanger 62, etc., which are inserted into the exhaust path 4.

[0031] As a result, in the cogeneration system 10 according to this embodiment, the engine body 2 drives the power generator 61 to generate electricity in the power generator 61, and the exhaust from the engine body 2 is passed through the heat exchanger 62 to generate (recover) heat in the heat exchanger 62. Therefore, the cogeneration system 10 is capable of generating and outputting electricity (electrical energy) and heat (thermal energy) when the engine body 2 is driven.

[0032] Furthermore, the cogeneration system 10 according to this embodiment has a housing 11, as shown in Figure 2. The engine unit 1, power generation unit 61, heat exchanger 62, etc., are housed inside the housing 11. In Figure 2, the frame of the housing 11 is shown, and the panels fixed to the frame are omitted as appropriate.

[0033] More specifically, the housing 11 has a structure in which the internal space is divided into two sections vertically D2, and the engine unit 1, power generator 61, and heat exchanger 62 are housed in the lower section of the divided internal space (housing space Sp1). In other words, the housing 11 has a housing space Sp1 inside, and at least the engine unit 1, power generator 61, and heat exchanger 62 are housed in this housing space Sp1. Here, the catalyst case 3, which is a component of the engine unit 1, is also housed in the same housing space Sp1 as the engine body 2.

[0034] [2] Structure around the catalyst case Next, the structure around the catalyst case 3 of the cogeneration system 10 (engine unit 1) according to this embodiment will be described with reference to Figures 3 to 8.

[0035] As shown in Figures 3 and 4, the engine unit 1 includes a cover member 31 (see Figure 4), an exhaust heat duct 32, an outer heat insulating material 33, a pair of inner heat insulating materials 34 (see Figure 3), and a pair of support parts 35 as peripheral structures of the catalyst case 3.

[0036] In this embodiment, as shown in Figure 5, the catalyst case 3 (which houses the catalyst 30) is formed in a hollow cylindrical shape with a length in the output axis direction D1. Both ends of the catalyst case 3 in the longitudinal direction (output axis direction D1) are conical in shape, with the outer diameter decreasing towards the outside (front or rear), and a flange portion 301 is integrally formed at the tip.

[0037] A pair of flange portions 301 are provided on both sides of the catalytic converter case 3 in the longitudinal direction, and piping constituting the exhaust path 4 is connected to each of them. Here, as an example, the first path 41 is connected to the rear flange portion 301 of the pair of flange portions 301, and the second path 42 is connected to the front flange portion 301. In other words, one end (rear end) of the catalytic converter case 3 in the longitudinal direction is connected to the engine body 2 (exhaust manifold 22) via the first path 41, and the other end (front end) is connected to the heat exchanger 62 via the second path 42.

[0038] Thus, the catalytic converter case 3 is inserted into the exhaust path 4 between the engine body 2 and the heat exchanger 62. As a result, as described above, the exhaust gas discharged from the engine body 2 is sent to the heat exchanger 62 through the catalytic converter case 3. At this time, the exhaust gas passes through the catalyst 30 housed in the catalytic converter case 3, and the catalyst 30 removes nitrogen oxides (NOx) from the exhaust gas. X ), hydrocarbons (HC) and carbon monoxide (CO) are reduced before reaching the heat exchanger 62.

[0039] The catalyst case 3 is positioned above the heat exchanger 62. Here, the catalyst case 3 is supported by the heat exchanger 62 by a pair of support parts 35. Specifically, the pair of support parts 35 are fixed on the upper surface of the heat exchanger 62, spaced apart in the output axial direction D1. Each of the pair of support parts 35 is fixed to a pair of flange parts 301. As a result, the catalyst case 3 is supported above the heat exchanger 62, spaced apart from the heat exchanger 62.

[0040] The catalyst case 3 (including a pair of flange portions 301), the first path 41, and the second path 42 are made of metallic materials such as aluminum alloy and cast iron. These components have the desired durability (including rigidity and wear resistance, etc.) and relatively good thermal conductivity. In this embodiment, as an example, the first path 41 and the second path 42 connected to the catalyst case 3 each protrude from the catalyst case 3 along the output axis direction D1 and have a curved (or bent) shape so that their ends extend downward.

[0041] When high-temperature exhaust gases pass through the catalytic converter case 3, the catalytic converter case 3 can become relatively hot. In particular, in the cogeneration system 10, the engine unit 1 may be operated under high load for extended periods, making the catalytic converter case 3 prone to becoming hot.

[0042] A pair of inner insulation materials 34 cover both ends of the catalyst case 3 in the longitudinal direction (output axis direction D1), the first path 41, and the second path 42. The pair of inner insulation materials 34 are, for example, polymer-based insulation materials and have sufficient thermal insulation performance compared to the catalyst case 3, etc. Each inner insulation material 34 is wrapped around the catalyst case 3 from each end in the longitudinal direction to the first path 41 or the second path 42 so as to cover each flange portion 301 as well. Each inner insulation material 34 is fixed to each end in the longitudinal direction of the catalyst case 3 by fasteners such as cable ties.

[0043] The cover member 31 is a member that is positioned around the catalyst case 3. Here, as shown in Figure 4, the cover member 31 is positioned to surround the catalyst case 3 while ensuring a predetermined gap between it and the outer surface of the catalyst case 3. In other words, the cover member 31 is not in contact with the catalyst case 3. The gap between the cover member 31 and the outer surface of the catalyst case 3 constitutes an air passage R1 through which the cooling air F1 (see Figure 7) passes.

[0044] In this embodiment, the cover member 31 has a length in the output axis direction D1 such that it covers the hollow cylindrical catalyst case 3, which has a length in the output axis direction D1, over substantially its entire length in the longitudinal direction. Here, the cover member 31 covers the top of the catalyst case 3 and both sides (left and right) in the width direction D3, while leaving the bottom of the catalyst case 3 and both sides (left and right) in the output axis direction D1 exposed.

[0045] Specifically, the cover member 31 is formed in a cylindrical shape with a length in the output axis direction D1, and its bottom surface and both ends in the longitudinal direction (output axis direction D1) are open. The inner circumferential surface of the cover member 31 is slightly larger than the outer circumferential surface of the catalyst case 3, and the catalyst case 3 can be housed within the area enclosed by the cover member 31. The cover member 31 is fixed to a pair of support parts 35, so that it is positioned around the catalyst case 3 without directly touching the catalyst case 3.

[0046] The cover member 31 is made of a metal material such as aluminum alloy and cast iron. The cover member 31 has desired durability (including rigidity and wear resistance, etc.) and relatively good thermal conductivity. Specifically, the cover member 31 is made of a metal plate having a predetermined thickness. Such a cover member 31 has heat-shielding properties.

[0047] In this embodiment, as an example, the cover member 31 has a first cover 311 and a second cover 312 that can be divided in the width direction D3, as shown in Figures 5 and 6. These first cover 311 and second cover 312 are fixed to a pair of support parts 35 from both sides of the catalyst case 3 in the width direction D3, and are connected to each other by fasteners such as bolts and nuts. This constitutes the cover member 31.

[0048] Here, as shown in Figure 6, the cover member 31 has both ends in the longitudinal direction (output axis direction D1) covering a pair of inner insulation materials 34. In other words, the pair of inner insulation materials 34 are provided as filler at both ends in the longitudinal direction of the cover member 31, closing both end faces of the cover member 31 in the longitudinal direction (output axis direction D1).

[0049] As described above, the engine device 1 according to this embodiment is equipped with an insulating material (inner insulating material 34) positioned between the cover member 31 and the catalytic converter case 3 at both ends in the exhaust flow direction (output axis direction D1) of the catalytic converter case 3. This prevents heat from the catalytic converter case 3 from leaking out from both ends in the exhaust flow direction (output axis direction D1) of the catalytic converter case 3.

[0050] Furthermore, as shown in Figure 4, the cover member 31 has an inlet 313 and an outlet 314 for the cooling air F1. That is, as described above, the cover member 31 forms an air passage R1 through which the cooling air F1 passes between itself and the outer circumferential surface of the catalyst case 3. The cover member 31 has an inlet 313, which is the upstream end in the flow direction of the cooling air F1 in the air passage R1, and an outlet 314, which is the downstream end in the flow direction of the cooling air F1 in the air passage R1. This allows the cooling air F1 to flow from the inlet 313 to the outlet 314 formed in the cover member 31, and allows the cooling air F1 to flow smoothly through the air passage R1.

[0051] Furthermore, the inlet 313 opens downwards toward the cover member 31. That is, since the cover member 31 has an open bottom surface, the bottom surface of the cover member 31 constitutes the inlet 313 for the cooling air F1. As a result, the cooling air F1 flowing through the air passage R1 can flow smoothly due to the upward airflow generated when the air taken in from the inlet 313 at its lower end is heated in the catalyst case 3.

[0052] Here, the inlet 313 is large enough to expose more than half of the catalyst case 3 when viewed from below. In other words, when viewed from below, the inlet 313 is larger than half the projection surface of the catalyst case 3, and more than half of the catalyst case 3 is exposed through the inlet 313. In this way, the inlet 313 is large enough compared to the catalyst case 3, so that a sufficient amount of cooling air F1 can be taken in from the inlet 313 and the cooling air F1 can be easily directed onto the catalyst case 3.

[0053] Furthermore, the outlet 314 opens upward toward the cover member 31. That is, the cover member 31 has an opening in a part of its upper surface, and this opening constitutes the outlet 314 for the cooling air F1. As a result, the air passage R1 discharges the cooling air F1 from the outlet 314 at its upper end, allowing the cooling air F1 flowing through the air passage R1 to flow smoothly due to the rising airflow generated by the heating in the catalyst case 3.

[0054] Specifically, as shown in Figures 4 and 5, the cover member 31 has an outlet 314, which is a through-hole extending vertically D2, located approximately in the center of the longitudinal direction (output axis direction D1) on the upper surface of the first cover 311. Here, as an example, the outlet 314 has a rectangular opening.

[0055] In this embodiment, as described above, the catalyst case 3 is housed in the same containment space Sp1 as the engine body 2. Here, the outlet 314 is connected to a heat exhaust port 112 (see Figure 2) for discharging heat from the containment space Sp1 to the outside of the containment space Sp1. This allows the cooling air F1 discharged from the outlet 314 of the cover member 31 to be discharged to the outside of the containment space Sp1 through the heat exhaust port 112. Therefore, the temperature of the containment space Sp1 can be prevented from rising by the diffusion of the cooling air F1 heated by the catalyst case 3 into the containment space Sp1.

[0056] Specifically, as shown in Figure 2, the internal space of the housing 11 includes a radiator space Sp2 located above the housing space Sp1. The housing space Sp1 and the radiator space Sp2 are separated by a drain pan 111 to prevent rainwater and other elements from entering the housing space Sp1. The drain pan 111 has a through hole that penetrates it in the vertical direction D2, and this through hole constitutes a heat exhaust port 112. In other words, the outlet 314 of the cooling air F1 in the cover member 31 is connected to the heat exhaust port 112 formed in the drain pan 111.

[0057] As shown in Figure 6, the exhaust duct 32 is a duct (piping) component that connects the outlet 314 and the exhaust port 112. For example, the exhaust duct 32 is rectangular in shape, protruding upward from the outlet 314, and its tip is bent to the right, forming a roughly L-shape. The exhaust duct 32 guides the cooling air F1 discharged from the outlet 314 of the cover member 31 to the exhaust port 112, and discharges it outside the containment space Sp1 from the exhaust port 112. This prevents the temperature of the containment space Sp1 from rising due to the diffusion of the cooling air F1 heated by the catalyst case 3 into the containment space Sp1.

[0058] The exhaust duct 32 is made of a metal material such as aluminum alloy and cast iron. The exhaust duct 32 has desired durability (including rigidity and wear resistance, etc.) and relatively good thermal conductivity. Specifically, the exhaust duct 32 is made of a metal plate having a predetermined thickness.

[0059] Here, the exhaust duct 32 is not in contact with the cover member 31. In other words, the exhaust duct 32 is not in contact with the cover member 31 and is floating relative to it. In this embodiment, the exhaust duct 32 is fixed to the housing 11. Therefore, even if the cover member 31 vibrates, for example when the engine body 2 is driven, such vibrations are unlikely to be transmitted to the exhaust duct 32. Conversely, vibrations of the exhaust duct 32 are also unlikely to be transmitted to the cover member 31.

[0060] Specifically, as shown in Figures 4 to 6, the cover member 31 has a cylindrical portion 315 that protrudes from the periphery of the outlet 314 toward the side opposite to the catalyst case 3. At least the tip of the cylindrical portion 315 is inserted into the outlet 314 side end of the exhaust heat duct 32. That is, the cover member 31 has a cylindrical portion 315 that extends upward around the outlet 314. The cylindrical portion 315 is a rectangular tube with a cross-sectional area slightly smaller than that of the exhaust heat duct 32. The tip (upper end) of the cylindrical portion 315 overlaps with the lower end of the exhaust heat duct 32, so that the cylindrical portion 315 and the exhaust heat duct 32 form a partially double-pipe structure.

[0061] This configuration makes it easier to introduce the cooling air F1 discharged from the outlet 314 into the heat exhaust duct 32, while keeping the heat exhaust duct 32 in non-contact with the cover member 31 (including the cylindrical portion 315). In other words, leakage of the cooling air F1 from the outlet 314 to the heat exhaust duct 32 becomes less likely.

[0062] As shown in Figures 3 and 4, the outer insulation material 33 covers the outside of the cover member 31 (the side opposite to the catalyst case 3). The outer insulation material 33 is, for example, a polymer-based insulation material and has sufficient thermal insulation performance compared to the cover member 31, etc. The outer insulation material 33 is wrapped around the cover member 31 from the outside so as to cover substantially the entire outer surface of the cover member 31. The outer insulation material 33 is fixed to the cover member 31 by fasteners such as cable ties.

[0063] As described above, the engine device 1 according to this embodiment comprises a catalyst case 3 and a cover member 31. The catalyst case 3 houses the catalyst 30 and allows exhaust gas discharged from the engine body 2 to pass through it. The cover member 31 is positioned around the catalyst case 3. The cover member 31 forms an air passage R1 between itself and the catalyst case 3 for passing cooling air F1. The cooling air F1 here consists of air or any gas, and should be at a temperature lower than the surface temperature of the catalyst case 3.

[0064] With this configuration, the catalytic converter case 3 can be cooled by the cooling air F1 passing through the air passage R1 between the cover member 31 and the catalytic converter case 3. Therefore, even if high-temperature exhaust gas passes through the catalytic converter case 3 that houses the catalytic converter 30, it becomes easier to suppress the temperature rise of the catalytic converter case 3 itself. Consequently, creep deformation of the catalytic converter case 3 that may occur in high-temperature environments can be suppressed, and tensile stress is less likely to occur at the joints between the catalytic converter case 3 and the piping (first passage 41 and second passage 42, etc.) after the engine body 2 is stopped, which has the advantage of making low-cycle fatigue less likely.

[0065] Specifically, as shown in Figure 7, air from the containment space Sp1 is drawn into the air passage R1 from the inlet 313 on the lower surface of the cover member 31. Here, the air drawn into the air passage R1 passes between the catalyst case 3 and the cover member 31 as cooling air F11 passing to the left of the catalyst case 3 and cooling air F12 passing to the right of the catalyst case 3.

[0066] The cooling air F1 (F11, F12) that has passed through the air passage R1 merges above the catalyst case 3 and is discharged as cooling air F13 through the exhaust duct 32 into the radiator space Sp2 from the outlet 314 on the upper surface of the cover member 31. This generates cooling air F1, which cools the catalyst case 3 and suppresses the temperature rise of the catalyst case 3.

[0067] Furthermore, because the cover member 31 has heat-shielding properties, the heat from the catalyst case 3 is blocked (shielded) by the cover member 31, making it difficult for the heat from the catalyst case 3 to diffuse into the containment space Sp1.

[0068] Furthermore, the engine device 1 according to this embodiment further includes an airflow generating unit 7 that generates airflow passing through the air passage R1, as shown in Figure 8. In Figure 8, the airflow generated by the airflow generating unit 7 is indicated by a dashed arrow.

[0069] In other words, the airflow generated by the airflow generation unit 7 cools the catalyst case 3 as it passes through the air passage R1 as cooling air F1. Here, the airflow generation unit 7 only needs to generate airflow that passes through the air passage R1, and may be a device that pressurizes and pumps air (gas) located upstream of the air passage R1 in the direction of airflow, or a device that sucks in air (gas) located downstream of the air passage R1. With this configuration, the airflow generation unit 7 can actively generate airflow (cooling air F1), and the catalyst case 3 can be actively cooled.

[0070] In this embodiment, as an example, the engine unit 1 includes a first airflow generating unit 71 consisting of a blower and a second airflow generating unit 72 consisting of a fan as an airflow generating unit 7. The first airflow generating unit 71 is located at the bottom of the containment space Sp1 and generates an airflow (cooling air F1) that passes through the air passage R1 by pressurizing and sending air (gas) into the containment space Sp1, thereby creating a positive pressure in the containment space Sp1. The second airflow generating unit 72 is located at the top of the radiator space Sp2 and generates an airflow (cooling air F1) that passes through the air passage R1 by drawing in air (gas) from the radiator space Sp2, thereby creating a negative pressure in the radiator space Sp2. The first airflow generating unit 71 and the second airflow generating unit 72 are controlled by a control unit, and the airflow volume or velocity of the cooling air F1 can be adjusted.

[0071] Furthermore, as shown in Figure 8, the engine device 1 according to this embodiment further includes a detection unit 83 that detects the temperature of the cooling air F1 coming out of the air passage R1. The detection unit 83 consists of a temperature sensor that measures the temperature of the cooling air F1 discharged from the outlet 314 and outputs an electrical signal corresponding to the measured value (temperature) to the control unit. This makes it possible to control the engine body 2 or the airflow generating unit 7, etc., according to the temperature of the cooling air F1 coming out of the air passage R1, making it easier to suppress an excessive temperature rise in the catalyst case 3.

[0072] [3] Variant The following lists some modifications of Embodiment 1. The modifications described below can be combined and applied as appropriate.

[0073] It is not essential for the cogeneration system 10 that at least some of its functions be integrated into a single housing 11; the components of the cogeneration system 10 may be distributed across multiple housings. Conversely, functions that are distributed across multiple devices in Embodiment 1 may be integrated into a single device.

[0074] Furthermore, the engine body 2 is not limited to a gas engine that uses gas as fuel, but may also be, for example, a diesel engine that uses diesel fuel, a gasoline engine that uses gasoline as fuel, or a hydrogen fuel engine that uses hydrogen as fuel. Moreover, the engine body 2 may be a so-called dual-fuel engine (DF engine) that can accommodate both a premixed combustion method in which gaseous fuel is mixed with air before being introduced into the combustion chamber, and a diffusion combustion method in which liquid fuel is injected into the combustion chamber and burned. Here, the gaseous fuel is hydrogen as an example, and the liquid fuel is fossil fuel (diesel fuel or gasoline, etc.) as an example. More specifically, by using diesel fuel as the liquid fuel, the engine body 2 can accommodate both a gas mode using hydrogen as fuel and a diesel mode using diesel fuel as fuel. Here, in the gas mode, a small amount of liquid fuel (diesel fuel, etc.) may be used as ignition fuel.

[0075] Furthermore, the engine device 1 is not limited to the cogeneration system 10, but may also be used as a power source for a mobile vehicle, for example.

[0076] Furthermore, the exhaust duct 32, outer insulation material 33, (a pair) of inner insulation material 34, and (a pair) of support parts 35 are not essential components and can be omitted as appropriate.

[0077] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0078] <Note 1> A catalytic converter case that houses the catalytic converter and through which exhaust gases discharged from the engine body pass, The catalyst case comprises a cover member arranged around it, The cover member forms an air passage for passing cooling air between itself and the catalyst case. Engine equipment.

[0079] <Note 2> The system further includes an airflow generating unit that generates airflow passing through the aforementioned air passage. The engine device described in Appendix 1.

[0080] <Note 3> The cover member has an inlet and an outlet for the cooling air. The engine device described in Appendix 1 or 2.

[0081] <Note 4> The aforementioned inlet opens toward the lower part of the cover member. The engine equipment described in Appendix 3.

[0082] <Note 5> The inlet is sized such that more than half of the catalyst case is exposed when viewed from below. The engine equipment described in Appendix 4.

[0083] <Note 6> The outlet opens upward toward the cover member. The engine device described in any of the appendices 3 to 5.

[0084] <Note 7> The catalyst case is housed in the same space as the engine body. The aforementioned outlet is connected to a heat exhaust port for discharging heat from the containment space to the outside of the containment space. The engine device described in any of the appendices 3 to 6.

[0085] <Note 8> The system further includes a heat exhaust duct connecting the aforementioned outlet and the heat exhaust port. The engine equipment described in Appendix 7.

[0086] <Note 9> The heat exhaust duct is not in contact with the cover member. The engine equipment described in Appendix 8.

[0087] <Note 10> The cover member has a cylindrical portion that protrudes from the periphery of the outlet toward the side opposite to the catalyst case, At least the tip of the cylindrical portion is inserted into the outlet end of the heat exhaust duct. The engine equipment described in Appendix 9.

[0088] <Note 11> The catalyst case further comprises a heat insulating material disposed between the cover member and the catalyst case at both ends in the direction of exhaust gas flow. An engine device as described in any of the appendices 1 to 10.

[0089] <Note 12> The system further includes a detection unit for detecting the temperature of the cooling air coming out of the air passage. An engine device as described in any of the appendices 1 to 11.

[0090] <Note 13> An engine device as described in any of the appendices 1 to 12, A power generation device that is driven by the engine body to generate electricity, The engine comprises a heat exchanger for extracting heat generated in the engine body, Cogeneration system. [Explanation of Symbols]

[0091] 1. Engine System 2. Engine body 3. Catalytic converter case 7. Airflow generating section 10. Cogeneration System 30 Catalyst 31 Cover component 32 Exhaust duct 34. Interior insulation (insulation material) 61 Power generation equipment 62 Heat exchanger 83 Detection unit 112 Heat exhaust port 313 Entrance 314 Exit 315 Cylindrical part F1 cooling air R1 wind path Sp1 Containment Space

Claims

1. A catalytic converter case that houses the catalytic converter and through which exhaust gases discharged from the engine body pass, The catalyst case comprises a cover member arranged around it, The cover member forms an air passage for passing cooling air between itself and the catalyst case. Engine unit.

2. The system further includes an airflow generating unit that generates airflow passing through the aforementioned air passage. The engine device according to claim 1.

3. The cover member has an inlet and an outlet for the cooling air. The engine device according to claim 1 or 2.

4. The aforementioned inlet opens toward the lower part of the cover member. The engine device according to claim 3.

5. The inlet is sized such that more than half of the catalyst case is exposed when viewed from below. The engine device according to claim 4.

6. The outlet opens upward toward the cover member. The engine device according to claim 3.

7. The catalyst case is housed in the same space as the engine body. The aforementioned outlet is connected to a heat exhaust port for discharging heat from the containment space to the outside of the containment space. The engine device according to claim 3.

8. The system further includes a heat exhaust duct connecting the aforementioned outlet and the heat exhaust port. The engine device according to claim 7.

9. The heat exhaust duct is not in contact with the cover member. The engine device according to claim 8.

10. The cover member has a cylindrical portion that protrudes from the periphery of the outlet toward the side opposite to the catalyst case, At least the tip of the cylindrical portion is inserted into the outlet end of the heat exhaust duct. The engine device according to claim 9.

11. The catalyst case further comprises a heat insulating material disposed between the cover member and the catalyst case at both ends in the direction of exhaust gas flow. The engine device according to claim 1 or 2.

12. The system further includes a detection unit for detecting the temperature of the cooling air coming out of the air passage. The engine device according to claim 1 or 2.

13. The engine device according to claim 1 or 2, A power generation device that is driven by the engine body to generate electricity, The engine comprises a heat exchanger for extracting heat generated in the engine body, Cogeneration system.

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