JP2016013524A - Dilution device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dilution device capable of appropriately diluting a main flow of anode off-gas or the like.SOLUTION: A dilution device 1 comprises: an introduction pipe 21 introducing first diluted gas; an atmospheric air introduction port 31 or the like attracting external atmospheric air and introducing the atmospheric air as an auxiliary flow by a negative pressure caused by the introduction of the first diluted gas from the introduction pipe 21; a dilution chamber 11 mixing the first diluted gas from the first introduction pipe 21 with the atmospheric air from the atmospheric air introduction port 31 and diluting the first diluted gas with the atmospheric air; and a vortex flow generation bar 51 disposed downstream of the introduction pipe 21, preventing the first diluted gas from the introduction pipe 21 from becoming a laminar flow, and generating a vortex flow of the first diluted gas.

Description

  The present invention relates to a dilution apparatus.

  Unreacted hydrogen is contained in the anode off gas discharged from the anode of the fuel cell, which is expected as a power source for vehicles. Therefore, a technique is known in which the anode off gas is diluted with a diluter and then discharged outside the vehicle (see Patent Document 1).

JP 2009-170209 A

  However, if the piping or diluter etc. through which the anode off gas flows are bent due to the layout or the like and the anode off gas flow is biased, the anode off gas is difficult to be diluted.

  Then, this invention makes it a subject to provide the dilution apparatus which can dilute mainstreams, such as anode off gas, favorably.

  As means for solving the above-mentioned problems, the present invention provides a substream that sucks external air and introduces it as a substream by a mainstream introduction section that introduces the mainstream and a negative pressure accompanying the introduction of the mainstream from the mainstream introduction section. A main flow introduction unit, a main flow from the main flow introduction unit and a sub flow from the sub flow introduction unit, a dilution unit for diluting the main flow with the sub flow, and a downstream of the main flow introduction unit, An unsteady flow generation unit that prevents laminar flow of the main flow from the introduction unit and generates an unsteady flow of the main flow.

  According to such a configuration, the unsteady flow generation unit prevents laminar flow of the main flow from the main flow introduction unit, and generates a main flow unsteady flow. As a result, the main flow is less likely to pass through the dilution section, and the unsteady flow main flow diffuses in the dilution section. Therefore, in the dilution section, the main stream and the side stream are mixed well, and the main stream is well diluted with the side stream.

  In the dilution apparatus, the unsteady flow generation unit is preferably a vortex flow generation unit that generates a mainstream vortex flow.

  According to such a configuration, the vortex generator can generate a mainstream vortex.

  In the dilution apparatus, it is preferable that the unsteady flow generation unit is directly provided in the main flow introduction unit.

  According to such a configuration, since the unsteady flow generation unit is directly provided in the main flow introduction unit, the unsteady flow generation unit can be easily positioned with respect to the main flow introduction unit.

  In the dilution apparatus, it is preferable that the unsteady flow generation unit is a bar member provided at an introduction port of the main flow introduction unit and dividing the introduction port.

  According to such a structure, an unsteady flow production | generation part can be simply comprised by the rod member which is provided in the inlet of a mainstream introduction part, and divides | segments an inlet.

  ADVANTAGE OF THE INVENTION According to this invention, the dilution apparatus which can dilute mainstreams, such as anode off gas, favorably can be provided.

It is a figure which shows the structure of the fuel cell system which concerns on this embodiment. (A) is a sectional side view of the dilution apparatus which concerns on this embodiment, (b) is an enlarged view of (a). It is a front view of the dilution apparatus which concerns on this embodiment, and respond | corresponds to the X1-X1 sectional view of FIG. It is a perspective view of the dilution apparatus which concerns on this embodiment. It is a figure which shows typically the dilution rate in the discharge port (X2-X2 sectional view of FIG. 2) of the dilution apparatus which concerns on this embodiment. It is a figure which shows typically the dilution rate in the dilution apparatus which concerns on a comparative example. It is a front view of the eddy current generating bar concerning a modification. It is a front view of the eddy current generating bar concerning a modification. It is a front view of the eddy current generating bar concerning a modification. It is a sectional side view of the dilution apparatus which concerns on a modification. It is a sectional side view of the dilution apparatus which concerns on a modification.

  An embodiment of the present invention will be described with reference to FIGS.

≪Configuration of fuel cell system≫
A fuel cell system 100 according to the present embodiment shown in FIG. 1 is mounted under a floor panel 211 (under the floor) of a fuel cell vehicle 200 (moving body). The fuel cell system 100 includes a fuel cell stack 110, an anode system that supplies and discharges hydrogen (fuel gas) to and from the anode of the fuel cell stack 110, and air containing oxygen to the cathode of the fuel cell stack 110 (oxidant) And a diluting device 1. The fuel cell system 100 may be mounted below the front bonnet of the fuel cell vehicle 200.

<Fuel cell stack>
The fuel cell stack 110 is a stack configured by stacking a plurality of (for example, 200 to 400) solid polymer type single cells, and the plurality of single cells are electrically connected in series. The single cell includes an MEA (Membrane Electrode Assembly) and two conductive anode separators and cathode separators sandwiching the MEA.

The MEA includes an electrolyte membrane (solid polymer membrane) made of a monovalent cation exchange membrane (for example, perfluorosulfonic acid type), and an anode and a cathode sandwiching the electrolyte membrane.
The anode and cathode are mainly composed of a conductive porous material such as carbon paper, and contain a catalyst (Pt, Ru, etc.) for causing an electrode reaction in the anode and cathode.

The anode separator is formed with a through-hole (called an internal manifold) extending in the stacking direction of the single cells and a groove extending in the surface direction of the single cells in order to supply and discharge hydrogen to the anode of each MEA. These through holes and grooves function as the anode flow path 111 (fuel gas flow path).
The cathode separator is formed with a through-hole (referred to as an internal manifold) extending in the stacking direction of the single cells and a groove extending in the surface direction of the single cells in order to supply and discharge air to and from the cathode of each MEA. These through holes and grooves function as the cathode channel 112 (oxidant gas channel).

  When hydrogen is supplied to each anode via the anode flow path 111, the electrode reaction of Formula (1) occurs, and when air is supplied to each cathode via the cathode flow path 112, Formula (2) Thus, a potential difference (OCV (Open Circuit Voltage), open circuit voltage) is generated in each single cell. Next, when the fuel cell stack 110 and an external circuit such as a travel motor are electrically connected and a current is taken out, the fuel cell stack 110 generates power. A part of the hydrogen is not consumed in the electrode reaction of the formula (1), but is discharged from the anode channel 111 to the pipe 121b.

2H ₂ → 4H ⁺ + 4e ⁻ (1)
O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)

<Anode system>
The anode system includes a hydrogen tank 121 (fuel gas supply means) and a normally closed purge valve 122.

  The hydrogen tank 121 is a container in which hydrogen is stored at a high pressure. The hydrogen tank 121 is connected to the inlet of the anode flow path 111 via a pipe 121a, and the hydrogen in the hydrogen tank 121 is supplied to the anode flow path 111 via the pipe 121a. The pipe 121a is provided with a normally closed shut-off valve and a regulator for appropriately reducing the hydrogen pressure.

  The outlet of the anode channel 111 is connected to the pipe 121a through the pipe 121b. The anode off gas containing hydrogen from the anode flow path 111 returns to the pipe 121 a through the pipe 121 b, and hydrogen circulates through the anode flow path 111. In addition, an ejector that generates negative pressure by injecting new hydrogen from the hydrogen tank 121 with a nozzle and sucks anode off-gas by this negative pressure is provided at a joint portion between the pipe 121b and the pipe 121a.

  The pipe 121b is connected to the pipe 131b through the pipe 122a, the purge valve 122, and the pipe 122b. When an unillustrated ECU (Electronic Control Unit, control device) opens the purge valve 122, the anode off-gas containing hydrogen is discharged to the pipe 131b through the pipe 122a and the pipe 122b. The piping 122b is provided with an orifice 123 that reduces the flow rate of the anode off gas.

<Cathode system>
The cathode system includes a compressor 131 (oxidant gas supply means).
The compressor 131 is connected to the inlet of the cathode channel 112 via a pipe 131a. When the compressor 131 operates in accordance with an instruction from the ECU, air containing oxygen outside the vehicle is compressed by intake air into the compressor 131 and supplied to the cathode flow path 112 through the pipe 131a.

  The outlet of the cathode channel 112 is connected to the diluting device 1 via a pipe 131b. Then, the cathode offgas from the cathode channel 112 goes to the diluting device 1 through the pipe 131b together with the anode offgas from the pipe 122b.

  The anode off gas merges with the cathode off gas, and then mixes with the cathode off gas, so that hydrogen in the anode off gas is diluted. Here, a gas generated by mixing the anode off gas and the cathode off gas is referred to as a first diluted gas for convenience. Further, as shown in FIG. 1, the downstream portion 131c of the pipe 131b is gradually increased toward the downstream.

≪Dilution device configuration≫
The dilution device 1 is a device that dilutes the first diluted gas (main flow) from the pipe 131b with the atmosphere (secondary flow) and discharges it outside the vehicle. Here, the gas obtained by diluting the first diluted gas in the atmosphere is defined as the second diluted gas.

  The diluting device 1 includes a cylindrical casing 10, an introduction pipe 21 (mainstream introduction part) that introduces the first diluted gas into the casing 10, and the introduction pipe 21 is fixed to the casing 10 and the casing 10. , And a vortex generator bar 51 fixed to the introduction pipe 21. In addition, the dilution apparatus 1 is arrange | positioned under the floor panel 211 which forms the floor surface of a trunk room, and is being fixed to the vehicle body via the stay (not shown).

<Case>
The housing 10 is a rectangular cylindrical and metal member that forms the skeleton of the diluting device 1 and extends in the front-rear direction, and has a diluting chamber 11 (diluting portion) inside thereof. The dilution chamber 11 is a space in which the first diluted gas (main flow) and the atmosphere (secondary flow) are mixed and the first diluted gas is diluted with the atmosphere. Note that, by diluting the first diluted gas, the second diluted gas in which the concentration of hydrogen contained in the first diluted gas is further reduced is obtained.

  The housing 10 includes a horizontal portion 12 that extends in the horizontal direction from the upstream side toward the downstream side, and an inclined portion 13 that extends from the downstream end of the horizontal portion 12 while being inclined obliquely downward and backward. In the gas flow direction, the flow path cross-sectional areas of the horizontal portion 12 and the inclined portion 13 are substantially the same. And the exit of the inclination part 13 comprises the discharge port 14 from the dilution apparatus 1 of the 2nd after-dilution gas outside a vehicle.

<Introduction pipe>
The introduction pipe 21 is a short cylindrical pipe for introducing the first diluted gas (main flow) into the dilution chamber 11 and extends in the front-rear direction. The introduction pipe 21 is disposed in the upstream portion of the horizontal portion 12 and at substantially the center of the horizontal portion 12 when viewed in the front-rear direction (as viewed in the gas flow direction) (see FIG. 3). In other words, the introduction pipe 21 is disposed at the approximate center of the horizontal portion 12 in the circular section of the horizontal portion 12.

  The downstream opening of the introduction pipe 21 constitutes an introduction port 22 for introducing the first diluted gas into the dilution chamber 11. The inlet 22 is divided by an eddy current generating bar 51 into an upper inlet 22A having an upper semicircular shape and a lower inlet 22B having a lower semicircular shape.

  In the front-rear direction, the upstream end surface of the introduction pipe 21 is disposed slightly behind the outer fitting portion 41 described later (see FIG. 2B). A downstream portion 131 c of the pipe 131 b is connected to the upstream end of the introduction pipe 21. Specifically, the downstream portion 131c is fixed to the stay 40 via the flange 23 with its rear end slightly protruding. An O-ring 24 (seal member) is provided between the downstream portion 131c and the introduction pipe 21, and the flange 23 and the introduction pipe 21 so that the gas after the first dilution does not leak. However, the introduction pipe 21 may not be provided, and for example, the downstream portion 131c may be inserted into the stay 40 and the downstream portion 131c may be an introduction tube.

  Then, when the first diluted gas is introduced into the horizontal portion 12 from the introduction pipe 21, a negative pressure is generated so that the external atmosphere is introduced through the air inlets 31 and 32 by this negative pressure. It has become.

<Stay>
The stay 40 is a metal member that fixes the introduction tube 21 to the horizontal portion 12, and includes an outer fitting portion 41 that is fitted on the introduction tube 21, and an inner periphery of the horizontal portion 12 that extends from the outer fitting portion 41 in a radially outward direction. Two legs 43 and legs 44 fixed to the surface.

  A short cylindrical portion 42 extending in the front-rear direction is formed at the center of the outer fitting portion 41, and the short cylindrical portion 42 is fitted on the introduction pipe 21. In other words, the introduction tube 21 is inserted into the short cylindrical portion 42. As described above, since the introduction tube 21 is inserted into the short cylindrical portion 42, even if the diluting device 1 vibrates with traveling, the posture of the introduction tube 21 is easily maintained.

  The leg portion 43 extends upward from the upper portion of the outer fitting portion 41 and is fixed to the center of the top wall surface of the inner peripheral surface of the horizontal portion 12. The outer side in the radial direction of the leg portion 43 is bent rearward to constitute a fixed portion 43 a fixed to the horizontal portion 12.

  The leg portion 44 extends downward from the lower portion of the outer fitting portion 41 and is fixed to the bottom wall surface of the inner peripheral surface of the horizontal portion 12. The outer side in the radial direction of the leg portion 44 is bent rearward to constitute a fixed portion 44 a fixed to the horizontal portion 12.

<Air inlet>
The air introduction ports 31 and 32 are gaps (spaces) formed between the stay 40 and the horizontal portion 12, and are introduction ports for introducing air into the horizontal portion 12. That is, the air introduction port 31 or the like is a sidestream introduction unit that sucks in the atmosphere and introduces it as a sidestream by the negative pressure accompanying the introduction of the first diluted gas.

  The air introduction port 31 is disposed on the left side of the stay 40. The air introduction port 32 is disposed on the right side of the stay 40.

<Swirl generation bar>
The vortex generating bar 51 is a round bar-like member that generates an eddy current of the first diluted gas from the introduction pipe 21. That is, the vortex generating bar 51 is an unsteady flow generating unit that prevents laminar flow of the first diluted gas in the dilution chamber 11 and generates an eddy current that is an unsteady flow of the first diluted gas. However, the eddy current generating bar 51 is not limited to a round bar shape, and may be, for example, an elongated plate shape.

  The vortex generating bar 51 extends in the left-right direction and is directly provided at the downstream end of the introduction pipe 21. The vortex generating bar 51 divides the inlet 22 of the inlet pipe 21 into an upper inlet 22A and a lower inlet 22B. The circumferential position of the vortex generator bar 51 can be adjusted as appropriate based on the distribution of hydrogen concentration after dilution.

≪Function and effect of dilution device≫
The effect of the dilution apparatus 1 is demonstrated.
The first diluted gas is introduced into the dilution chamber 11 through the introduction pipe 21. When the first diluted gas is introduced through the introduction pipe 21 in this way, a negative pressure is generated in the vicinity of the downstream end of the introduction pipe 21, and the negative pressure causes the atmosphere outside the vehicle to be introduced into the atmosphere introduction ports 31 and 32. Through the dilute chamber 11.

  In this case, since the vortex generating bar 51 is fixed at the downstream end of the introduction pipe 21, the cross-sectional area of the introduction port is smaller than the configuration without the vortex generating bar 51. Therefore, when the flow rate of the first diluted gas is constant, the flow rate of the first diluted gas increases because the cross-sectional area of the inlet is small. Therefore, the negative pressure increases and it becomes easy to suck the atmosphere. Therefore, since the suction flow rate of the atmosphere is increased, the gas after the first dilution can be diluted more satisfactorily.

  The first diluted gas and the atmosphere are mixed in the dilution chamber 11, and the first diluted gas is diluted in the atmosphere and the hydrogen concentration is lowered. The second diluted gas generated by mixing the first diluted gas and the atmosphere is discharged out of the vehicle through the discharge port 14.

  Here, the first diluted gas collides with the vortex generating bar 51 extending in the left-right direction, is divided into two forks in the vertical direction, and is introduced into the dilution chamber 11 through the upper inlet 22A and the lower inlet 22B. Thus, since the first diluted gas collides with the vortex generating bar 51 extending in the left-right direction, the first diluted gas after the collision becomes Karman vortex flow (see FIG. 2, arrow A1), and the first diluted gas is It diffuses in the vertical direction (vertical direction).

  In this case, the width of the vortex in the vertical direction is proportional to the vertical length (diameter) of the vortex generating bar 51. That is, as the vertical length increases, the width of the vortex in the vertical direction increases. In addition, the vortex generation cycle is proportional to the flow rate of the first diluted gas. That is, as the flow rate of the first diluted gas increases, the vortex generation cycle increases.

  Since the first diluted gas becomes a Karman vortex and diffuses in the vertical direction in this way, the first diluted gas and the atmosphere are well mixed in the vertical direction in the dilution chamber 11. The second diluted gas produced by mixing in this way is diluted substantially evenly in the cross-sectional direction of the outlet port 14 (see FIG. 5). That is, it is difficult to form an uneven hydrogen concentration distribution in the cross-sectional direction of the outlet port 14. In FIG. 5, the discharge port 14 is divided into regions S1 to S9 for convenience, and “◯” attached to the region S1 or the like indicates that hydrogen has been diluted at a predetermined magnification (dilution rate) or more. Show.

On the other hand, when the eddy current generating bar 51 is not provided, the first diluted gas from the introduction pipe 21 is likely to travel straight forward through the dilution chamber 11 (see arrow A2 in FIG. 2). In this way, the gas after the first dilution travels straight, passes through the dilution chamber 11 as it is, and becomes difficult to be diluted with the atmosphere. Therefore, as shown in FIG. It becomes easy to become. That is, when the eddy current generating bar 51 is not provided, the hydrogen concentration is uneven in the vertical direction at the discharge port 14.
Therefore, in order to promote diffusion of the first diluted gas (target gas) in the vertical direction, the eddy current generating bar 51 extending in the horizontal direction is provided, and the first diluted gas is divided and introduced in the vertical direction.

  In this way, by generating a Karman vortex by the vortex generator bar 51 and diffusing the gas after the first dilution in the vertical direction, hydrogen can be diluted well. For example, the casing 10 is shortened in the front-back direction. it can. That is, the diluting device 1 can be reduced in size.

≪Modification≫
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, For example, you may change as follows.

  In the above-described embodiment, the configuration in which the vortex generating bar 51 is fixed to the downstream end of the introduction pipe 21 is exemplified. However, for example, the configuration in which the vortex generation bar 51 is arranged apart from the downstream end of the introduction pipe 21. But you can. That is, a configuration in which the vortex generating bar 51 is arranged downstream of the introduction pipe 21 may be used. In this case, the vortex generating bar 51 is fixed to the housing 10 via an arm, for example. Further, the vortex generating bar 51 may be arranged in the introduction pipe 21, that is, slightly upstream from the downstream end face of the introduction pipe 21. In addition, even if it is such a structure, the same effect can be acquired and it belongs to the technical scope of this invention.

  In the above-described embodiment, the eddy current generating bar 51 is configured to extend in the left-right direction and diffuse the first diluted gas in the up-down direction. However, for example, it is necessary to diffuse the first diluted gas in the left-right direction. In this case, as shown in FIG. 7, the vortex generating bar 52 extending in the vertical direction is fixed to the introduction pipe 21.

  In addition, when it is necessary to diffuse the first diluted gas in the up-down direction and the left-right direction, a cross-shaped eddy current generating bar 53 (see FIG. 8) or a Y-shaped eddy current generating bar 54 (see FIG. 9) is used. The configuration is fixed to the introduction pipe 21. Moreover, it is good also as a structure provided with the mesh of a suitable mesh instead of the eddy current generation bar 51. FIG.

  As shown in FIG. 10, the diluter 1 may be configured to include a fan 61 (unsteady flow generator) instead of the vortex generator bar 51 (see FIG. 2). The fan 61 is provided downstream of the introduction pipe 21 so as to agitate the first diluted gas from the introduction pipe 21 in the cross section direction of the horizontal portion 12 (see arrow A3). The fan 61 may be configured to be rotated by the first diluted gas, or may be configured to be rotated by a motor or the like.

  As shown in FIG. 11, the diluting device 1 may include a conical umbrella-shaped fin 62 (unsteady flow generating unit) instead of the vortex generating bar 51 (see FIG. 2). The fins 62 are provided downstream of the introduction pipe 21 so as to agitate the first diluted gas from the introduction pipe 21 in the cross-sectional direction of the horizontal portion 12 (see arrow A4).

  In the above-described embodiment, the configuration in which the dilution target gas is hydrogen discharged from the fuel cell stack 110 is illustrated, but other types of gas may be used.

DESCRIPTION OF SYMBOLS 1 Dilution apparatus 10 Case 11 Dilution chamber (dilution part)
21 Introduction pipe (mainstream introduction part)
22 Inlet 31 and 32 Air inlet (sidestream inlet)
51, 52, 53, 54 Eddy current generation bar (unsteady flow generator)
61 Fan (unsteady flow generator)
62 Fin (unsteady flow generator)
100 Fuel cell system 110 Fuel cell stack

Claims (4)

A mainstream introduction section for introducing the mainstream,
A substream introduction section that sucks external air and introduces it as a substream by the negative pressure accompanying the introduction of the mainstream from the mainstream introduction section;
A dilution section for mixing the main flow from the main flow introduction section and the sub flow from the sub flow introduction section, and diluting the main flow with the sub flow;
An unsteady flow generation unit that is arranged downstream of the main flow introduction unit and prevents laminarization of the main flow from the main flow introduction unit and generates a main flow unsteady flow;
A dilution apparatus comprising: The dilution apparatus according to claim 1, wherein the unsteady flow generation unit is a vortex generation unit that generates a mainstream vortex. The dilution apparatus according to claim 1, wherein the unsteady flow generation unit is directly provided in the main flow introduction unit. The dilution apparatus according to claim 3, wherein the unsteady flow generation unit is a rod member that is provided at an introduction port of the main flow introduction unit and divides the introduction port.

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