Dilution device

Abstract

To provide a dilution device that can improve the dilution performance of gas to be diluted by dilution gas inside a housing.SOLUTION: A plate member (50, 60) causes gas to be diluted that has flowed into first space (DS1, DS1-1, DS1-2) to remain in a first space (DS1, DS1-1, DS1-2), causes the dilution gas that has flowed into a second space (DS2) to flow into the first space (DS1, DS1-1, DS1-2), and causes the mixed gas of the gas to be diluted and the dilution gas formed in the first space (DS1, DS1-1, DS1-2) to flow back from the first space (DS1, DS1-1, DS1-2) to the second space (DS2) and flow out from a mixed gas outflow portion (40).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a dilution device. [Background technology]

[0002] Patent Document 1 describes an exhaust gas dilution device for a fuel cell. This exhaust gas dilution device for a fuel cell has a container capable of containing hydrogen gas discharged from the anode electrode side, and an inlet and outlet provided in the container. Hydrogen gas is introduced into the container through the inlet, while air discharged from the cathode electrode side flows through the container. The hydrogen gas contained in the container is discharged through the outlet into an air distribution pipe, which discharges the air into the atmosphere from an outlet provided at one end, and the hydrogen gas is mixed with the air in the air distribution pipe, thereby diluting the hydrogen gas with the air and discharging it into the atmosphere. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-179894 Summary of the Invention [Problem to be solved by the invention]

[0004] However, according to the inventor's intensive research, the prior art including Patent Document 1 has room for improvement in terms of improving the dilution performance of the dilution target gas by the dilution gas inside the housing.

[0005] An object according to one aspect of the present invention is to provide a dilution device that can improve the dilution performance of a gas to be diluted with a dilution gas inside a housing. [Means for solving the problem]

[0006] One embodiment of the dilution device according to the present invention comprises a housing having a dilution gas inlet section for receiving a gas to be diluted, a dilution gas inlet section for receiving a dilution gas, a mixed gas outlet section for receiving a mixed gas of the gas to be diluted and the dilution gas, and a plate member that divides the internal space of the housing into a first space and a second space that are mutually ventilated, wherein the dilution gas inlet section allows the gas to be diluted to flow into the first space, the dilution gas inlet section allows the dilution gas to flow into the second space, and the mixed gas outlet section allows the mixed gas to flow out from the second space, and the plate member causes the dilution gas that has flowed into the first space to remain in the first space, causes the dilution gas that has flowed into the second space to flow into the first space, and causes the mixed gas of the gas to be diluted and the dilution gas formed in the first space to return from the first space to the second space and flow out from the mixed gas outlet section.

[0007] In this way, by installing a plate member that divides the internal space of the housing into a first space and a second space that are mutually ventilated, and by using the inflow and return flow action (gradual dilution action from the first space to the second space) spanning the first and second spaces via the plate member, the flow paths of the dilution target gas, dilution gas, and mixed gas of the dilution target gas and dilution gas within the housing are optimized, thereby improving dilution performance. More specifically, by guiding the dilution gas that has flowed into the second space to the first space and forming a stirring flow in the first space, the concentration of the dilution target gas that has flowed into the first space can be efficiently reduced in a short time. In this respect, the dilution device of this embodiment is distinguished from conventional technologies that simply flow the dilution target gas and dilution gas into the housing and then discharge the mixed gas.

[0008] The plate member may have a partition plate that divides the internal space of the housing into a first space and a second space that are mutually ventilated, and a baffle plate that divides the first space into a 1-1 space and a 1-2 space that are mutually ventilated, and the 1-2 space is formed between the 1-1 space and the second space, and the dilution target gas inlet portion may cause the dilution target gas to flow into the 1-1 space.

[0009] In this way, by making the plate member into a two-piece structure consisting of a partition plate that divides the internal space of the housing into a first space and a second space that are mutually ventilated, and a baffle plate that divides the first space into a 1-1 space and a 1-2 space that are mutually ventilated, an inflow and return action spanning the 1-1 space, 1-2 space, and second space (a gradual dilution action from the 1-1 space to the 1-2 space and then to the second space) is obtained.

[0010] The baffle plate may cause the gas to be diluted that has flowed into the 1-1 space to remain in the 1-1 space, the partition plate and the baffle plate may cause the dilution gas that has flowed into the second space to flow into the 1-1 space and the 1-2 space, the baffle plate may cause a first mixed gas of the gas to be diluted and the dilution gas formed in the 1-1 space to return from the 1-1 space to the 1-2 space, and the partition plate may cause a second mixed gas of the first mixed gas and the dilution gas formed in the 1-2 space to return from the 1-2 space to the second space and cause it to flow out from the mixed gas outflow portion.

[0011] This allows for an inflow / backflow action (a stepwise dilution action from the 1-1 space to the 1-2 space and then to the 2 space) across the 1-1 space, 1-2 space, and 2-space via the partition plate and baffle plate, optimizing the flow paths of the dilution target gas, dilution gas, and the mixed gas of the dilution target gas and dilution gas (the first mixed gas and the second mixed gas) inside the housing, thereby improving dilution performance. More specifically, by guiding the dilution gas that has flowed into the 2-space to the 1-1 space and the 1-2 space and forming a stirring flow in the 1-1 space and the 1-2 space, the concentration of the dilution target gas that has flowed into the 1-1 space can be efficiently reduced in a short time. Furthermore, for example, by placing a baffle plate near the inlet of the dilution target gas in the 1-1 space, it is possible to prevent a large amount of the dilution target gas from flowing out immediately after injection, thereby suppressing an instantaneous increase in the concentration of the dilution target gas. In addition, a flow of dilution gas is formed in the 1-1 space and the 1-2 space, which accelerates the dilution of the gas to be diluted, and reduces the flow rate and concentration of the gas to be diluted contained in the mixed gas flowing out from the mixed gas outlet of the second space.

[0012] The partition plate may have a main body portion located at the boundary between the 1-2 space and the second space, a side / lower inlet portion formed on the side / lower side of the main body portion and allowing the dilution gas that has flowed into the second space to flow into the 1-2 space, and an upper return portion formed on the upper side of the main body portion and allowing the second mixed gas of the first mixed gas and the dilution gas formed in the 1-2 space to return from the 1-2 space to the second space.

[0013] This allows the partition plate to define the inflow route of the dilution gas through the side / lower inflow section and the return route of the second mixed gas through the upper return section, thereby optimizing the inflow / return action across the first-second space and the second space via the partition plate (the stepwise dilution action from the first-second space to the second space), thereby improving dilution performance.

[0014] The dilution gas inlet may be located at a position offset in one direction in the width direction of the partition plate, and the side / lower inlet of the partition plate may have two side / lower inlet sections spaced apart in the width direction of the partition plate, and the inlet area of ​​the side / lower inlet on the side where the dilution gas inlet is offset may be set to be larger than the inlet area of ​​the side / lower inlet on the side where the dilution gas inlet is not offset.

[0015] This makes it possible to balance the inflow of diluent gas through the two side / lower inflow sections, even if the diluent gas inflow section is provided at a position offset in one direction in the width direction of the partition plate.

[0016] The baffle plate may have: a main body portion located at the boundary between the 1-1 space and the 1-2 space; a side / lower inlet portion formed on the side / lower side of the main body portion and allowing the dilution gas that has flowed into the 1-2 space to flow into the 1-1 space; and an upper return portion formed on the upper side of the main body portion and allowing the first mixed gas of the gas to be diluted and the dilution gas formed in the 1-1 space to return from the 1-1 space to the 1-2 space.

[0017] This makes it possible to separately define the inflow route of the dilution gas through the side / lower inflow portion and the return route of the first mixed gas through the upper return portion in the baffle, thereby optimizing the inflow / return action across the 1-1 space and the 1-2 space via the baffle (the stepwise dilution action from the 1-1 space to the 1-2 space), thereby improving the dilution performance.

[0018] The dilution gas inlet port may be provided at a position offset in one direction in the width direction of the baffle, and the side / lower inlet port of the baffle may have two side / lower inlet ports spaced apart in the width direction of the baffle, and an inflow area of ​​the side / lower inlet port on the side where the dilution gas inlet port is offset, out of the two side / lower inlet ports, may be set to be larger than an inflow area of ​​the side / lower inlet port on the side where the dilution gas inlet port is not offset.

[0019] This makes it possible to balance the inflow of diluent gas through the two side / lower inlets, even if the diluent gas inlet is provided at a position offset in one direction in the width direction of the baffle.

[0020] The partition plate may be provided adjacent to the dilution gas inlet portion, and the baffle plate may be provided adjacent to the dilution gas inlet portion.

[0021] This allows the inflow and return action (stepwise dilution action from the 1-1 space to the 1-2 space and then to the 2 space) across the 1-1 space, 1-2 space, and 2-space via the partition plate and baffle plate to optimize the airflow paths of the dilution gas, dilution gas, and mixture of the dilution gas and dilution gas (first mixture gas, second mixture gas) inside the housing, thereby improving dilution performance. Furthermore, by providing the partition plate adjacent to the dilution gas inlet, the dilution gas can be efficiently introduced into the 1-1 space and the 1-2 space immediately after intake. Furthermore, by providing the baffle plate adjacent to the dilution gas inlet, it is possible to prevent a large amount of the dilution gas from flowing out immediately after injection, thereby suppressing an instantaneous increase in the concentration of the dilution gas.

[0022] The dilution device may include a position changer that changes the position of the plate member inside the housing.

[0023] This makes it possible to change the attitude of the plate members (partition plates, baffles) inside the housing by the attitude changing unit (for example, by rotating them around a predetermined rotation axis) in response to various conditions such as the usage conditions of the dilution device and environmental conditions. Therefore, the inflow and return action (stepwise dilution action from the 1-1 space to the 1-2 space and then to the second space) across the 1-1 space, the 1-2 space, and the second space via the plate members (partition plates, baffles) optimizes the airflow paths of the gas to be diluted, the dilution gas, and the mixed gas of the gas to be diluted and the dilution gas (first mixed gas, second mixed gas) inside the housing, thereby improving dilution performance.

[0024] The dilution target gas inlet may allow the dilution target gas to flow in intermittently, and the dilution gas inlet may allow the dilution gas to flow in continuously.

[0025] This allows the gas to be diluted, which intermittently flows in from the gas to be diluted inlet, to be efficiently diluted by the dilution gas, which continuously flows in from the dilution gas inlet.

[0026] The gas to be diluted may be anode off-gas discharged from the anode of the fuel cell when an exhaust / drain valve is opened, and the dilution gas may be cathode off-gas discharged from the cathode of the fuel cell.

[0027] This allows the hydrogen discharged from the fuel cell to be diluted with air at an appropriate time (to form a mixed gas) and then discharged (discharged) to the outside of the housing. [Effects of the Invention]

[0028] According to the present invention, it is possible to provide a dilution device that can improve the dilution performance of a gas to be diluted with a dilution gas inside a housing. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view showing an example of the configuration of a dilution device of a first embodiment. [Figure 2] 1 is a side view showing an example of the configuration of a dilution device of a first embodiment. [Figure 3] FIG. 10 is a diagram showing an example of the front shapes of a partition plate and a baffle plate. [Figure 4] FIG. 1 is a first diagram showing the state of airflow inside the housing. [Figure 5] FIG. 2 is a second diagram showing the state of airflow inside the housing. [Figure 6] FIG. 10 is a perspective view showing an example of the configuration of a dilution device according to a second embodiment. [Figure 7] FIG. 10 is a perspective view showing an example of the configuration of a dilution device according to a third embodiment. [Figure 8] FIG. 10 is a perspective view showing an example of the configuration of a dilution device according to a fourth embodiment. [Figure 9] FIG. 10 is a perspective view showing an example of the configuration of a dilution device according to a fifth embodiment. [Figure 10] FIG. 13 is a perspective view showing an example of the configuration of a dilution device according to a sixth embodiment. [Figure 11] FIG. 10 is a diagram showing the results of a first experiment and simulation demonstrating the superiority of the dilution device of the present embodiment. [Figure 12] FIG. 10 is a diagram showing the results of a second experiment and simulation demonstrating the superiority of the dilution device of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0030] <Definitions of terms, etc.> In this specification, the term "gas to be diluted" refers to a solute gas that needs to be diluted to a lower concentration at the time of outflow than at the time of inflow, and the term "dilution gas" refers to a solvent gas that is added to the gas to be diluted to dilute its concentration. In the following embodiment, a case is exemplified in which a dilution device is incorporated into a fuel cell (system), the gas to be diluted is anode off-gas (hydrogen) discharged from the anode of the fuel cell (stack) when the exhaust / drain valve is opened, and the dilution gas is cathode off-gas (air) discharged at the cathode of the fuel cell (stack). However, there is a degree of freedom in the specific aspects of the gas to be diluted and the dilution gas, and various design modifications are possible.

[0031] In the following embodiments, the plate member divides the internal space of the housing into a first space and a second space that are mutually ventilated, and regulates the air flow in the first space and the second space. More specifically, the plate member causes the gas to be diluted that has flowed into the first space to remain in the first space, causes the dilution gas that has flowed into the second space to flow into the first space, and causes the mixed gas of the gas to be diluted and the dilution gas formed in the first space to return from the first space to the second space and flow out from the mixed gas outflow port.

[0032] In the following embodiments, the partition plate divides the internal space of the housing into a first space and a second space that are mutually ventilated, and the baffle plate divides the first space into a 1-1 space and a 1-2 space that are mutually ventilated, thereby regulating the air flows in the 1-1 space, the 1-2 space, and the second space. More specifically, the baffle plate causes the gas to be diluted that has flowed into the 1-1 space to remain in the 1-1 space, the partition plate and the baffle plate cause the dilution gas that has flowed into the second space to flow into the 1-1 space and the 1-2 space, the baffle plate causes the first mixed gas of the gas to be diluted and the dilution gas formed in the 1-1 space to return from the 1-1 space to the 1-2 space, and the partition plate causes the second mixed gas of the first mixed gas and the dilution gas formed in the 1-2 space to return from the 1-2 space to the second space and flow out from the mixed gas outflow portion.

[0033] The above definition means that, from a macroscopic perspective, such an air flow exists inside the housing (for example, accounting for more than half or the majority), but does not exclude (preclude) the existence of an opposite air flow inside the housing from a microscopic perspective. For example, inside the housing, there may be some components of the dilution gas that has flowed into the second space and is discharged from the mixed gas outlet port without flowing into the first space (1-1 space and 1-2 space). Also, there may be some components of the gas to be diluted that has flowed into the first space (1-1 space) and is not retained in the first space (1-1 space) (without being mixed with the dilution gas) but moves to the second space (1-2 space).

[0034] In this specification, "A / B" means "A and B," "A or B," "A and / or B," or "at least one of A and B." For example, "side / lower inlet portion" may mean an inlet portion provided on the side, an inlet portion provided on the lower side, an inlet portion provided on each of the side and the lower side, or an inlet portion provided across (straddling) both the side and the lower side.

[0035] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the following description, the length, width, and height directions are based on the direction of the arrows shown in the drawings. The length direction may be read as the front-to-back direction, the width direction may be read as the left-to-right direction, and the height direction may be read as the up-to-down direction.

[0036] First Embodiment Fig. 1 is a perspective view showing an example of the configuration of the dilution device 1 of the first embodiment. Fig. 2 is a side view showing an example of the configuration of the dilution device 1 of the first embodiment.

[0037] The dilution device 1 is incorporated into a fuel cell (system) that generates electricity by chemically reacting hydrogen and oxygen, and is used to dilute and discharge hydrogen that does not undergo chemical reaction. For example, the dilution device 1 is required to be able to dilute the hydrogen concentration at the inlet to about 1 / 10 to 1 / 20.

[0038] The dilution device 1 has a tank-shaped housing 10. The housing 10 can maintain an internal space in a sealed and airtight state, excluding a hydrogen inlet 20, an air inlet 30, and an exhaust outlet 40, which will be described later. The material of the housing 10 is flexible and various design changes are possible, but it may be made of stainless steel, which is iron to which chromium, nickel, molybdenum, or the like is added, or may be made of plastic such as carbon fiber reinforced plastics (CFRP) or polypropylene.

[0039] A hydrogen inlet 20 is provided (connected) on the lower side of one end face (front end face) in the longitudinal direction (front-rear direction) of the housing 10. The hydrogen inlet 20 allows hydrogen that is not able to undergo chemical reaction in the fuel cell (system) and is discharged to flow into the housing 10. The hydrogen flowing into the hydrogen inlet 20 may be read as the "gas to be diluted," and the hydrogen inlet 20 may be read as the "gas to be diluted inlet portion."

[0040] An air inlet 30 is provided (connected) on the upper surface of the housing 10 at the middle in the longitudinal direction (front-rear direction). The air inlet 30 allows air taken in from outside the housing 10 by an air compressor of the fuel cell (system) to flow into the housing 10. The air flowing into the air inlet 30 may be read as "dilution gas," and the air inlet 30 may be read as "dilution gas inlet portion."

[0041] An exhaust outlet 40 is provided (connected) on the other end face (rear end face) in the longitudinal direction (front-rear direction) of the housing 10, that is, on the lower side of the face opposite the hydrogen inlet 20. The exhaust outlet 40 allows the hydrogen that flows in from the hydrogen inlet 20 and the air that flows in from the air inlet 30, which have been mixed inside the housing 10, to flow out of the housing 10. The mixture of hydrogen and air that flows out from the exhaust outlet 40 may be read as a "mixed gas," and the exhaust outlet 40 may be read as a "mixed gas outflow portion."

[0042] The hydrogen inlet (dilution gas inlet) 20 allows hydrogen (dilution gas) discharged from the fuel cell (system) to flow in intermittently (at predetermined time intervals, for example, every few tens of seconds) by opening and closing the exhaust and drain valve. The air inlet (dilution gas inlet) 30 allows air taken in from outside the casing 10 to flow in continuously (at all times). However, the hydrogen inlet 20 may allow hydrogen to flow in continuously, or the air inlet 30 may allow air to flow in intermittently. In other words, there is a degree of freedom in the manner in which hydrogen and air flow in through the hydrogen inlet 20 and air inlet 30, and various design modifications are possible.

[0043] The housing 10 is provided with a partition plate 50 that divides the interior space of the housing 10 into a first space DS1 and a second space DS2 that are mutually ventilated, and a baffle plate 60 that divides the first space DS1 into a first-1 space DS1-1 and a first-2 space DS1-2 that are mutually ventilated. A first-2 space DS1-2 is formed between the first-1 space DS1-1 and the second space DS2, and a hydrogen inlet (gas to be diluted) 20 introduces hydrogen (gas to be diluted) into the first-1 space DS1-1. The partition plate 50 is located at the other end (rear side) of the housing 10 in the longitudinal direction (front-rear direction), and the baffle plate 60 is located at one end (front side) of the housing 10 in the longitudinal direction (front-rear direction). The partition plate 50 and the baffle plate 60 may be interpreted as "plate members," or the partition plate 50 may be interpreted as the "first plate member," and the baffle plate 60 as the "second plate member."

[0044] The hydrogen inlet (dilution gas inlet) 20 allows hydrogen (dilution gas) to flow into the 1-1 space DS1-1 of the first space DS1. The air inlet (dilution gas inlet) 30 allows air (dilution gas) to flow into the second space DS2. The exhaust outlet (mixed gas outlet) 40 allows the mixture of hydrogen and air (mixed gas) to flow out from the second space DS2.

[0045] FIG. 3A is a diagram showing an example of the front shape of the partition plate 50, and FIG. 3B is a diagram showing an example of the front shape of the baffle plate 60. As shown in FIG.

[0046] As shown in FIG. 3A, the partition plate 50 has a main body portion 51 located at the boundary between the first-second space DS1-2 and the second space DS2. The main body portion 51 has a pair of side edge portions 52 that face (abut) both end faces of the housing 10 in the width direction (left-right direction). The main body portion 51 has a bottom edge portion 53 that faces (abuts) a middle portion of the bottom surface of the housing 10 in the width direction (left-right direction). A pair of downward inflow holes 54 are formed on both sides of the bottom edge portion 53 in the width direction (left-right direction). The main body portion 51 has an upper edge portion 55 that faces the top surface of the housing 10, and a small gap between this upper edge portion 55 and the top surface of the housing 10 forms an upper return hole 56.

[0047] As shown in FIG. 3B , the baffle plate 60 has a main body portion 61 located at the boundary between the 1-1 space DS1-1 and the 1-2 space DS1-2. The main body portion 61 has a side edge portion 62 facing (abutting) one end face (left end face) in the width direction (left-right direction) of the housing 10, and a side edge portion 63 facing the other end face (right end face) in the width direction (left-right direction) of the housing 10 with a gap therebetween. The main body portion 61 has a bottom edge portion 64 facing (abutting) the middle portion in the width direction (left-right direction) of the bottom surface of the housing 10. A lower side of the side edge portion 62 is cut out, and this cutout portion forms a lower inlet hole 65. A lateral space between the side edge portion 63 and the housing 10 forms a lateral inlet hole 66. The main body 61 has an upper side 67 that faces the upper surface of the housing 10 , and a small gap between the upper side 67 and the upper surface of the housing 10 forms an upper return hole 68 .

[0048] The baffle plate 60 causes hydrogen (gas to be diluted) that has flowed into the 1-1 space DS1-1 to remain in the 1-1 space DS1-1. The partition plate 50 and the baffle plate 60 cause air (dilution gas) that has flowed into the second space DS2 to flow into the 1-1 space DS1-1 and the 1-2 space DS1-2. The baffle plate 60 causes a first mixed gas, which is a mixture of hydrogen (gas to be diluted) and air (dilution gas) formed in the 1-1 space DS1-1, to return from the 1-1 space DS1-1 to the 1-2 space DS1-2. The partition plate 50 causes a second mixed gas, which is a mixture of the first mixed gas and hydrogen (gas to be diluted) formed in the 1-2 space DS1-2, to return from the 1-2 space DS1-2 to the second space DS2, and causes it to flow out from the exhaust outlet (mixed gas outflow section) 40.

[0049] In this way, the inflow and return action (stepwise dilution action from the 1-1 space DS1-1 to the 1-2 space DS1-2 and then to the second space DS2) across the 1-1 space DS1-1, the 1-2 space DS1-2, and the second space DS2 via the partition plate 50 and the baffle plate 60 optimizes the flow paths of hydrogen (gas to be diluted), air (dilution gas), and mixed gases (first mixed gas, second mixed gas) that are a mixture of hydrogen (gas to be diluted) and air (dilution gas) inside the casing 10, thereby improving dilution performance. More specifically, by guiding the air (dilution gas) that has flowed into the second space DS2 to the 1-1 space DS1-1 and the 1-2 space DS1-2 and forming a stirring flow in the 1-1 space DS1-1 and the 1-2 space DS1-2, the concentration of hydrogen (gas to be diluted) that has flowed into the 1-1 space DS1-1 can be efficiently reduced in a short time. Furthermore, for example, by placing a baffle plate 60 near the hydrogen inlet (dilution target gas inlet) 20 of the 1-1 space DS1-1, it is possible to prevent a large amount of hydrogen (dilution target gas) from flowing out immediately after injection and suppress an instantaneous increase in the concentration of hydrogen (dilution target gas). Also, by forming a flow of air (dilution gas) in the 1-1 space DS1-1 and the 1-2 space DS1-2, it is possible to hasten the dilution of hydrogen (dilution target gas) and reduce the flow rate and concentration of hydrogen (dilution target gas) contained in the mixed gas (second mixed gas) flowing out from the exhaust outlet (mixed gas outlet) 40 of the second space DS2.

[0050] The pair of downward inlet holes 54 of the partition plate 50 function as "side / lower inlet portions." The pair of downward inlet holes 54 are formed on the side / lower sides of the main body portion 51, and function to allow air (dilution gas) that has flowed into the second space DS2 to flow into the first-second space DS1-2.

[0051] The upper return hole 56 of the partition plate 50 functions as an "upper return portion." The upper return hole 56 is formed on the upper side of the main body portion 51, and has the function of returning the second mixed gas, which is a mixture of the first mixed gas and hydrogen (gas to be diluted) formed in the 1-2 space DS1-2, from the 1-2 space DS1-2 to the second space DS2.

[0052] This makes it possible to separately define an inflow route of air (dilution gas) through the pair of lower inflow holes 54 (side / lower inflow portion) and a return route of the second mixed gas through the upper return hole 56 (upper return portion) in the partition plate 50. As a result, the inflow and return action across the first-2 space DS1-2 and the second space DS2 via the partition plate 50 (stepwise dilution action from the first-2 space DS1-2 to the second space DS2) can be optimized, thereby improving dilution performance.

[0053] The downward inlet holes 65 and the side inlet holes 66 of the baffle plate 60 function as "side / lower inlet portions." The downward inlet holes 65 and the side inlet holes 66 are formed on the side / lower sides of the main body portion 61, and have the function of allowing air (dilution gas) that has flowed into the 1-2 space DS1-2 to flow into the 1-1 space DS1-1.

[0054] The upper return hole 68 of the baffle plate 60 functions as an "upper return portion." The upper return hole 68 is formed on the upper side of the main body portion 61, and has the function of returning the first mixed gas, which is a mixture of hydrogen (gas to be diluted) and air (diluent gas) formed in the 1-1 space DS1-1, from the 1-1 space DS1-1 to the 1-2 space DS1-2.

[0055] This makes it possible to separately define an inflow route of air (dilution gas) through the downward inlet holes 65 and the side inlet holes 66 (side / lower inlet portion) and a return route of the first mixed gas through the upward return holes 68 (upper return portion) in the baffle 60. As a result, the inflow and return action across the 1-1 space DS1-1 and the 1-2 space DS1-2 via the baffle 60 (stepwise dilution action from the 1-1 space DS1-1 to the 1-2 space DS1-2) can be optimized, thereby improving dilution performance.

[0056] The partition plate 50 is provided adjacent to the air inlet (dilution gas inlet) 30, and the baffle plate 60 is provided adjacent to the hydrogen inlet (dilution gas inlet) 20. As a result, the inflow and return action (stepwise dilution action from the 1-1 space DS1-1 to the 1-2 space DS1-2 and then to the second space DS2) via the partition plate 50 and the baffle plate 60 optimizes the flow paths of hydrogen (dilution gas), air (dilution gas), and mixed gases (first mixed gas, second mixed gas) that are a mixture of hydrogen (dilution gas) and air (dilution gas) inside the casing 10, thereby improving dilution performance. Furthermore, by providing the partition plate 50 adjacent to the air inlet (dilution gas inlet) 30, the air (dilution gas) immediately after intake can be efficiently flowed into the 1-1 space DS1-1 and the 1-2 space DS1-2. Furthermore, by providing the baffle plate 60 adjacent to the hydrogen inlet (dilution gas inlet) 20, it is possible to prevent a large amount of hydrogen (dilution gas) from flowing out immediately after injection, thereby suppressing an instantaneous increase in the concentration of hydrogen (dilution gas).

[0057] Fig. 4 is a first diagram showing the state of airflow inside the housing 10. Figs. 5A to 5D are second diagrams showing the state of airflow inside the housing 10. Figs. 5A to 5D focus on the air that flows in (takes in) from the air inlet 30 and illustrate the flow of that air.

[0058] The air that flows in from the air inlet 30 hits the lower surface (bottom surface) of the housing 10 in the second space DS2, then hits the main body 51 of the partition plate 50, splits into two, left and right, and flows into the 1-2 space DS1-2 through a pair of downward inlet holes 54 (on the near side of the page of the partition plate 50 and the baffle plate 60) of the partition plate 50. A portion of the air that has flowed into the 1-2 space DS1-2 remains in the 1-2 space DS1-2 and moves upward (on the far side of the page of the partition plate 50 and the baffle plate 60), and the other portion flows into the 1-1 space DS1-1 and moves upward through the downward inlet hole 65 and the side inlet hole 66 of the baffle plate 60. The pair of downward inlet holes 54 of the partition plate 50 and the downward inlet holes 65 and side inlet holes 66 of the baffle plate 60 are open at the bottom of both ends in the width direction (left and right direction), so it is possible to create an airflow that flows along the bottom of both ends in the width direction (left and right direction) inside the housing 10. Furthermore, by restricting the opening area of ​​the pair of downward inlet holes 54 of the partition plate 50 and the downward inlet holes 65 and side inlet holes 66 of the baffle plate 60, it is possible to increase the flow velocity and cause the air to flow deep inside (to reach the 1-1 space DS1-1).

[0059] In the 1-1 space DS1-1, hydrogen flowing in from the hydrogen inlet 20 collides with the main body 61 of the baffle 60 and remains in the 1-1 space DS1-1. Furthermore, air moving from below to above in the 1-1 space DS1-1 mixes with the hydrogen retained by the main body 61 of the baffle 60 to form a first mixed gas, which then passes through the upper return holes 68 of the baffle 60 and moves to the 1-2 space DS1-2. In the 1-2 space DS1-2, air moving from below to above mixes with the first mixed gas to form a second mixed gas, which then passes through the upper return holes 56 of the partition plate 50 and moves to the second space DS2. Then, in the second space DS2, the second mixed gas is accelerated by the air flowing in from the air inlet 30 (with some mixing) and flows out from the exhaust outlet 40. In other words, the air inlet 30 is positioned so that the air flowing in from the air inlet 30 gives momentum to the second mixed gas that has moved from the upper return hole 68 of the baffle plate 60 and directs it toward the exhaust outlet 40.

[0060] The airflow described above can be achieved due to the optimization of the structure (shape) of the partition plate 50 and the baffle plate 60, as well as the fact that oxygen is heavier (has a higher specific gravity) than hydrogen. The air flowing in from the air inlet 30 contains oxygen and is therefore heavy, so it flows from the second space DS2 to the 1-2 space DS1-2 and then to the 1-1 space DS1-1 through the pair of downward inlet holes 54 of the partition plate 50 and the downward inlet hole 65 and the side inlet hole 66 of the baffle plate 60 (the so-called downward path). On the other hand, the first mixed gas formed in the 1-1 space DS1-1 and the second mixed gas formed in the 1-2 space DS1-2 are lighter because they contain hydrogen, so they pass through the upper return hole 56 of the partition plate 50 and the upper return hole 68 of the baffle plate 60, and are returned from the 1-1 space DS1-1 to the 1-2 space DS1-2 and then to the second space DS2 (the so-called upward path).

[0061] Second Embodiment Fig. 6 is a perspective view showing an example of the configuration of a dilution device 1 of a second embodiment. In the second embodiment of Fig. 6, the baffle plate 60 of the first embodiment of Fig. 1 is omitted, and the plate member is only a partition plate 50.

[0062] In the second embodiment, the internal space of the housing 10 is divided into a first space DS1 and a second space DS2 that are mutually ventilated by the partition plate 50. The partition plate 50 causes hydrogen (gas to be diluted) that has flowed into the first space DS1 to remain in the first space DS1, causes air (dilution gas) that has flowed into the second space DS2 to flow into the first space DS1, and causes the mixed gas of hydrogen (gas to be diluted) and air (dilution gas) formed in the first space DS1 to flow back from the first space DS1 to the second space DS2 and then flows out from the exhaust outlet 40.

[0063] <Third embodiment> Fig. 7 is a perspective view showing an example of the configuration of a dilution device 1 of a third embodiment. In the third embodiment of Fig. 7, the partition plate 50 of the first embodiment of Fig. 1 is omitted, and the plate member is only a baffle plate 60.

[0064] In the third embodiment, the internal space of the housing 10 is divided into a first space DS1 and a second space DS2 that are mutually ventilated by the baffle plate 60. The baffle plate 60 causes hydrogen (gas to be diluted) that has flowed into the first space DS1 to remain in the first space DS1, causes air (dilution gas) that has flowed into the second space DS2 to flow into the first space DS1, and causes the mixed gas of hydrogen (gas to be diluted) and air (dilution gas) formed in the first space DS1 to flow back from the first space DS1 to the second space DS2 and then flows out from the exhaust outlet 40.

[0065] In the first embodiment described above, two plate members, the partition plate 50 and the baffle plate 60, are used, in the second embodiment described above, one plate member, the partition plate 50, is used, and in the third embodiment described above, one plate member, the baffle plate 60, is used. However, embodiments (variations) using three or more plate members are of course also possible. Furthermore, when one plate member is used, the installation position thereof may be intermediate between the hydrogen inlet 20 and the air inlet 30 or in the vicinity thereof.

[0066] <Fourth embodiment> 8A and 8B are diagrams showing an example of the configuration of the dilution device 1 of the fourth embodiment, illustrating variations in the structure (shape) of the plate member 70 installed inside the housing 10. For ease of explanation, in FIGS. 8A and 8B, the internal space of the housing 10 is depicted as being rectangular.

[0067] 8A and 8B, plate member 70 has a main body 71 located at the boundary between two adjacent different spaces (for example, the boundary between the first space and the second space, the boundary between the 1-2 space and the second space, or the boundary between the 1-1 space and the 1-2 space). In FIGS. 8A and 8B, the main body 71 of plate member 70 and housing 10 are depicted as having a slight gap therebetween, but the two may abut against each other and their positions may be restricted relative to each other (the plate member 70 may be fitted into housing 10).

[0068] 8A, the side / lower inflow portions formed in the main body portion 71 are two notches 72X formed on the lower sides of a pair of side edges of the main body portion 71, and two notches 72Y formed on both the left and right sides of the bottom edge of the main body portion 71. In addition, the upper return portion formed in the main body portion 71 is one notch 73 formed in most of the top edge of the main body portion 71, including the center in the left-right direction.

[0069] 8B, two notches 74 having stepped portions formed across the lower sides of a pair of side edges of the main body 71 and both left and right sides of the bottom edge of the main body 71 are formed as side / lower inflow portions formed in the main body 71. In addition, one notch 75 that becomes deeper in stages from the left and right directions of the top edge of the main body 71 toward the center is formed as an upper return flow portion formed in the main body 71.

[0070] The plate member 70 illustrated in FIGS. 8A and 8B may be used as at least one of the partition plate 50 and the baffle plate 60. However, the structure (shape) of the plate member 70 can be modified in various ways as long as it can fulfill the functions of the side / lower inlet portion and the upper reflux portion. For example, the plate member 70 may be rectangular (oblong) without any notches. When the plate member 70 is used as the baffle plate 60, it is sufficient that the structure (shape) can cover the periphery of the hydrogen inlet 20. When the plate member 70 is used as the partition plate 50 and the baffle plate 60, the orientations of the plates do not need to be parallel to each other and may have a predetermined angle (incline) with respect to the gas flow. Furthermore, only one side / lower inlet portion may be provided, or multiple upper reflux portions may be provided.

[0071] Fifth Embodiment 9A and 9B are diagrams showing an example of the configuration of the dilution device 1 of the fifth embodiment.

[0072] 9A and 9B, the partition plate 50 has two side / lower inlet portions spaced apart in the width direction (left-right direction) (corresponding to the pair of lower inlet holes 54 in the first embodiment). Also, the baffle plate 60 has two side / lower inlet portions spaced apart in the width direction (left-right direction) (corresponding to the lower inlet hole 65 and the side inlet hole 66 in the first embodiment).

[0073] The air inlet (dilution gas inlet) 30 is provided at a position offset in one direction in the width direction (left-right direction) of the partition plate 50 and the baffle plate 60. For example, in Fig. 9A, the air inlet 30 is provided at a position offset to the right side of the figure, and in Fig. 9B, the air inlet 30 is provided at a position offset to the left side of the figure.

[0074] Of the two side / lower inlet portions of each of the partition plate 50 and the baffle plate 60, the inlet area of ​​the side / lower inlet portion on the side where the air inlet 30 is biased is set larger than the inlet area of ​​the side / lower inlet portion on the side where the air inlet 30 is not biased. For example, in Fig. 9A, the inlet area of ​​the side / lower inlet portion on the right side of the partition plate 50 and the baffle plate 60 is set larger than the inlet area of ​​the side / lower inlet portion on the left side of the partition plate 50 and the baffle plate 60. Conversely, in Fig. 9B, the inlet area of ​​the side / lower inlet portion on the left side of the partition plate 50 and the baffle plate 60 is set larger than the inlet area of ​​the side / lower inlet portion on the right side of the partition plate 50 and the baffle plate 60.

[0075] This makes it possible to balance the inflow of air (dilution gas) through each of the two side / lower inflow sections, even if the air inlet (dilution gas inlet) 30 is located at a position offset in one direction in the width direction (left / right direction) of the partition plate 50 and the baffle plate 60.

[0076] Sixth Embodiment 10 is a diagram showing an example of the configuration of the dilution device 1 of the sixth embodiment. The dilution device 1 of the sixth embodiment has a posture changer that changes the posture of the plate member inside the housing 10.

[0077] More specifically, the posture conversion unit has a rotation axis 50X provided on the partition plate 50, a rotation axis 60X provided on the baffle plate 60, and a drive mechanism (including, for example, a motor, gears, and shafts) that rotates the partition plate 50 and the baffle plate 60 around the rotation axis 50X and the rotation axis 60X.

[0078] This allows the partition plate 50 and the baffle plate 60 to rotate about the rotation axis 50X and the rotation axis 60X in response to various conditions, such as the usage conditions and environmental conditions of the dilution device 1. Therefore, due to the inflow and return action across the 1-1 space DS1-1, the 1-2 space DS1-2, and the second space DS2 via the partition plate 50 and the baffle plate 60 (a stepwise dilution action from the 1-1 space DS1-1 to the 1-2 space DS1-2 and then to the second space DS2), the paths of the gas flows of hydrogen (gas to be diluted), air (dilution gas), and a mixed gas of hydrogen (gas to be diluted) and air (dilution gas) (first mixed gas, second mixed gas) inside the casing 10 are optimized, thereby improving dilution performance.

[0079] The posture changer has a degree of freedom in its configuration, and a guide mechanism for moving the plate member linearly (horizontally) inside the housing 10 may be provided.

[0080] <Experimental and simulation results> 11A and 11B are diagrams showing the results of a first experiment and simulation demonstrating the superiority of the dilution device 1 of this embodiment. FIG. 11A shows the time transition of the concentration index (concentration evaluation value) in the dilution device 1 of the first embodiment (with both the partition plate 50 and the baffle plate 60), and FIG. 11B shows the time transition of the concentration index (concentration evaluation value) in the dilution device 1 of the second embodiment (with only the partition plate 50). Both dilution devices 1 exhibit good dilution performance. In particular, the hydrogen concentration in the dilution device 1 of the first embodiment is better than the hydrogen concentration in the dilution device 1 of the second embodiment.

[0081] FIG. 12 shows the results of a second experiment and simulation demonstrating the advantages of the dilution device 1 of this embodiment. FIG. 12 shows the hydrogen distribution concentration immediately after hydrogen injection (0.2 seconds after hydrogen injection) and the hydrogen distribution concentration immediately before the next hydrogen injection. As can be seen from FIG. 12, the hydrogen distribution concentration temporarily increases immediately after hydrogen injection, but converges to a low level by the time the next hydrogen injection occurs. This allows for a high (sufficient) hydrogen discharge capacity to be achieved.

[0082] As described above, the dilution device of this embodiment includes a housing provided with a dilution gas inlet through which a gas to be diluted flows, a dilution gas inlet through which a dilution gas flows, a mixed gas outlet through which a mixed gas of the gas to be diluted and the dilution gas flows, and a plate member that divides the internal space of the housing into a first space and a second space that are mutually ventilated. The dilution gas inlet allows the gas to be diluted to flow into the first space, the dilution gas inlet allows the dilution gas to flow into the second space, and the mixed gas outlet allows the mixed gas to flow out from the second space. The plate member causes the gas to be diluted that flows into the first space to remain in the first space, causes the dilution gas that flows into the second space to flow into the first space, and returns the mixed gas of the gas to be diluted and the dilution gas formed in the first space from the first space to the second space and flows out from the mixed gas outlet. This improves the dilution performance of the gas to be diluted by the dilution gas inside the housing. In other words, the gas to be diluted can be diluted efficiently in a short time. In addition, since the device only requires providing a plate member inside the housing, it can be mounted at low cost and in a small space.

[0083] For example, when the dilution device of this embodiment is applied to an exhaust gas dilution device for a fuel cell (system), it can achieve two contradictory functions at a practical level: reducing the exhaust hydrogen concentration (not emitting large amounts of hydrogen) and quickly discharging all hydrogen before the next injection, while achieving these functions with a simple structure. Specifically, it can dilute the hydrogen concentration at the inlet to about 1 / 10 to 1 / 20 at the outlet. It can also accommodate intermittent hydrogen injection (remaining hydrogen can be diluted within several tens of seconds before the next injection).

[0084] The components of the dilution device of this embodiment can also be understood as follows. This dilution device is designed to dilute high-concentration hydrogen discharged from a fuel cell stack during fuel cell power generation to a standard concentration or lower, at low cost and in a small footprint, and then discharge the hydrogen. A hydrogen inlet is provided at one end of the dilution device, an exhaust port at the other end, and an air inlet near the other end. First and second partition plates are also provided between the hydrogen inlet and the air inlet. The first partition plate is spaced apart from the hydrogen inlet, and the second partition plate is spaced apart from the air inlet, with gaps formed between the inner surface of the dilution device and the first and second partition plates, respectively. The flow velocity of the air introduced through the air inlet is such that it passes through the gaps between the first and second partition plates and reaches the vicinity of the hydrogen inlet just before the next hydrogen injection cycle (this allows gas inflow and return).

[0085] In the aforementioned Patent Document 1, the containment body has a gas inlet communicating with the anode-side exhaust pipe at one end and a gas outlet at the other end, and a tip opening of the upstream exhaust pipe of the cathode-side exhaust pipe near the other end. A first shielding plate and a second shielding plate are disposed between the gas inlet and the tip opening. The second shielding plate is spaced apart from the gas inlet and has a gap with the inner bottom surface of the containment body to form a second through-hole. The first shielding plate is spaced apart from the gas inlet and has a gap with the inner surface of the upper wall of the containment body to form a first through-hole at a position closer to the tip opening than the second shielding plate. In Patent Document 1, even if the hydrogen gas discharged from the anode side mixes with air as it flows in a zigzag pattern while colliding with the first and second shielding plates, it cannot be said that the air from the tip opening of the cathode-side exhaust pipe has a flow rate sufficient to pass through the gaps around the first and second shielding plates and reach the gas inlet. In this regard, Patent Document 1 does not disclose or suggest the feature of the dilution device of this embodiment, namely, that the plate member causes the gas to be diluted that flows into the first space to remain in the first space, causes the dilution gas that flows into the second space to flow into the first space, and causes the mixed gas of the gas to be diluted and the dilution gas formed in the first space to flow back from the first space to the second space and out through the mixed gas outflow section. [Explanation of symbols]

[0086] 1 Dilution device 10. Cabinet 20 Hydrogen inlet (gas to be diluted) 30 Air inlet (dilution gas inlet) 40 Exhaust outlet (mixed gas outflow section) 50 Partition plate (plate member, first plate member) 50X rotation axis 51 Main body 52 Side part 53 Bottom 54 Lower inflow hole (side / lower inflow part) 55 Top 56 Upper reflux hole (upper reflux part) 60 baffle plate (plate member, second plate member) 60X rotation axis 61 Main body 62 Side part 63 lateral part 64 lower part 65 Lower inflow hole (side / lower side inflow part) 66 Side inflow hole (side / bottom side inflow part) 67 upper part 68 Upper return hole (upper side return part) 70 Plate material 71 Body part 72X 72Y Cut-out (side / bottom inflow) 73 Cut-off section (upper side return section) 74 Cut-out (side / bottom inflow) 75 Cut-off part (upper side return part) DS1 Space 1 DS1-1 Space 1-1 DS1-2 Space 1-2 DS2 Space 2

Claims

1. Installed in the housing, a dilution target gas inlet portion into which the dilution target gas flows; a dilution gas inlet for receiving the dilution gas; a mixed gas outlet portion through which a mixed gas of the gas to be diluted and the dilution gas flows out; a plate member that divides the internal space of the housing into a first space and a second space that are airtight; and the dilution target gas inlet portion causes the dilution target gas to flow into the first space, the dilution gas inlet portion causes the dilution gas to flow into the second space, the mixed gas outlet portion allows the mixed gas to flow out from the second space, The plate member causes the gas to be diluted that has flowed into the first space to remain in the first space, causes the dilution gas that has flowed into the second space to flow into the first space, and causes the mixed gas of the gas to be diluted and the dilution gas formed in the first space to return from the first space to the second space and flow out from the mixed gas outflow portion. Dilution device.

2. The dilution device according to claim 1, The plate member is a partition plate that divides the internal space of the housing into a first space and a second space that are mutually ventilated; a baffle plate that divides the first space into a 1-1 space and a 1-2 space that are mutually ventilated; and The first-second space is formed between the first-first space and the second space, The dilution target gas inlet portion causes the dilution target gas to flow into the 1-1 space. Dilution device.

3. The dilution device according to claim 2, the baffle plate causes the gas to be diluted that has flowed into the 1-1 space to remain in the 1-1 space, the partition plate and the baffle plate cause the dilution gas that has flowed into the second space to flow into the 1-1 space and the 1-2 space, the baffle plate causes a first mixed gas of the gas to be diluted and the dilution gas formed in the 1-1 space to return from the 1-1 space to the 1-2 space, and the partition plate causes a second mixed gas of the first mixed gas and the dilution gas formed in the 1-2 space to return from the 1-2 space to the second space and flow out from the mixed gas outflow portion. Dilution device.

4. The dilution device according to claim 3, The partition plate is a main body portion located at the boundary between the first-second space and the second space; a side / lower inlet portion formed on a side / lower side of the main body portion and allowing the dilution gas that has flowed into the second space to flow into the first-second space; an upper reflux section formed on an upper side of the main body section and configured to reflux the second mixed gas of the first mixed gas and the dilution gas formed in the first-2 space from the first-2 space to the second space; having Dilution device.

5. The dilution device according to claim 4, the dilution gas inlet is provided at a position offset in one direction in the width direction of the partition plate, The side / lower inlet portion of the partition plate has two side / lower inlet portions spaced apart in a width direction of the partition plate, an inflow area of ​​the side / lower inflow portion on the side where the dilution gas inflow portion is biased out of the two side / lower inflow portions is set to be larger than an inflow area of ​​the side / lower inflow portion on the side where the dilution gas inflow portion is not biased out of the two side / lower inflow portions; Dilution device.

6. The dilution device according to claim 3, The baffle plate is a main body portion located at the boundary between the 1-1 space and the 1-2 space; a side / lower inlet portion formed on a side / lower side of the main body portion and allowing the dilution gas flowing into the 1-2 space to flow into the 1-1 space; an upper reflux section formed on an upper side of the main body section and configured to reflux the first mixed gas of the gas to be diluted and the dilution gas formed in the 1-1 space from the 1-1 space to the 1-2 space; having Dilution device.

7. The dilution device according to claim 6, the dilution gas inlet portion is provided at a position offset in one direction in the width direction of the baffle plate, the side / lower inlet portion of the baffle plate has two side / lower inlet portions spaced apart in a width direction of the baffle plate, an inflow area of ​​the side / lower inflow portion on the side where the dilution gas inflow portion is biased out of the two side / lower inflow portions is set to be larger than an inflow area of ​​the side / lower inflow portion on the side where the dilution gas inflow portion is not biased out of the two side / lower inflow portions; Dilution device.

8. The dilution device according to claim 2, the partition plate is provided adjacent to the dilution gas inlet portion, The baffle plate is provided adjacent to the dilution target gas inlet portion. Dilution device.

9. The dilution device according to claim 1 or 2, a posture change unit that changes the posture of the plate member inside the housing; Dilution device.

10. The dilution device according to claim 1 or 2, the dilution target gas inlet portion allows the dilution target gas to intermittently flow in, The dilution gas inlet section continuously introduces the dilution gas. Dilution device.

11. The dilution device according to claim 1 or 2, the gas to be diluted is an anode off-gas discharged from the anode of the fuel cell when an exhaust / drain valve is opened; The dilution gas is a cathode off-gas discharged from the cathode of the fuel cell. Dilution device.

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