JP2005273704A - Valve device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent a movable part from freezing and improve startability by a simple and economical structure. <P>SOLUTION: A valve device 48 is provided with a lead-in flow passage 56 leading in exhaust gas, a lead-out flow passage 60 leading out the exhaust gas, and a merging flow passage 62 merging the lead-in flow passage 56 and the lead-out flow passage 60. The merging flow passage 62 is provided with an open and close mechanism 64. A predetermined gap H is formed between a end part 68a of a valve element 68 and an upper part wall part 78 at a position where the valve element 68 constructing the open close mechanism 64 separates from a valve seat 66 and gets closest to the upper part wall part 78 constructing the merging flow passage 62. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to, for example, a valve device provided in an exhaust gas line that discharges reaction gas used for power generation of a fuel cell as exhaust gas from the fuel cell.

  For example, a polymer electrolyte fuel cell employs an electrolyte membrane made of a polymer ion exchange membrane. A fuel cell is configured by sandwiching an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are provided on both sides of the electrolyte membrane with a separator. Each of the anode side electrode and the cathode side electrode has a noble metal-based electrode catalyst layer bonded to a base material mainly composed of carbon.

  In this fuel cell, a fuel gas, for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas) is supplied to the anode side electrode, while an oxidant gas, for example, A gas or air mainly containing oxygen (hereinafter also referred to as oxygen-containing gas) is supplied. In the fuel gas supplied to the anode side electrode, hydrogen is ionized on the electrode catalyst and moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy.

  By the way, in such a fuel cell, the power generation state continues for a long time, so that impurities accumulate, the anode side electrode surface is covered with water, and the reaction gas is not sufficiently supplied, so that the power generation voltage decreases. There's a problem. Therefore, in order to maintain an efficient power generation state while maintaining the life of the fuel cell, the flow rate and pressure of the fuel gas and the oxidant gas are appropriately controlled and supplied, and the exhaust gas containing water is supplied at an appropriate timing. It is necessary to discharge (so-called purge) to the outside.

  The valve mechanism used for the purge is always in contact with water vapor or water droplets for drainage, and may freeze when used below freezing. In particular, when the movable part of the valve mechanism freezes, the valve mechanism becomes inoperable. For this reason, the function of the valve mechanism is also stopped until the movable portion is thawed, and there is a problem that it takes time for the thaw to start the valve mechanism quickly.

  Therefore, for example, it is conceivable to adopt the technical idea disclosed in Patent Document 1. In Patent Document 1, as shown in FIG. 5, a first port portion 3 a and a second port portion 3 b are formed on the case portion 2 constituting the valve 1 in the vertical direction, and the first and second ports are formed. The portions 3 a and 3 b communicate with the space portion 4. A tapered portion 4 a communicates with the lower side of the space portion 4.

  A valve body 5 is disposed in the space 4 so as to be able to advance and retract. The flat upstream end portion 5a of the valve body 5 can freely open and close the first port portion 3a, and the tapered downstream end portion 5b of the valve body 5 is in close contact with the taper portion 4a to be second. The port 3b can be opened and closed freely.

  The valve body 5 is provided with a protrusion 6 on the outer peripheral portion on the upstream end portion 5a side. A spring 7 is interposed between one end side of the protrusion 6 and the case part 2, while a shape memory alloy spring 8 is interposed between the other end part of the protrusion 6 and the case part 2. Is intervening. On the outer periphery of the shape memory alloy spring 8, a heater coil 9 is disposed around the case portion 2.

  The shape memory alloy spring 8 communicates the first port portion 3a and the second port portion 3b against the urging force of the spring 7 at a set temperature or lower, for example, 0 ° C. or lower, and water accumulates in the valve 1. It is preventing that. When the valve 1 is driven, the heater coil 9 is energized to generate heat, and the shape memory alloy spring 8 is heated to a set temperature or higher so that the valve 1 can operate normally. Yes.

Japanese Utility Model Publication No. 2-63015 (FIG. 1)

  However, in Patent Document 1 described above, the heater coil 9 must be energized in order to heat the shape memory alloy spring 8 to a set temperature or higher. Accordingly, there is a problem that a considerable amount of heat is required, which is not economical and the startability is deteriorated.

  The present invention solves this type of problem, and an object thereof is to provide a valve device that can effectively prevent freezing of a movable part with a simple and economical configuration and is excellent in startability.

  The valve device according to the present invention includes an introduction channel into which a gas is introduced, a derivation channel from which the gas is derived, a merging channel in which the introduction channel and the derivation channel merge, and the merging flow And an opening / closing mechanism that is provided in the passage and can freely open and close the merging passage.

  The opening / closing mechanism includes a valve body that can advance and retreat under the action of the drive unit, and a valve seat that the valve body is seated to close the merging flow path, and the valve body is separated from the valve seat. A gap is formed between the end portion of the valve body and the wall portion at a position closest to the wall portion constituting the merge channel.

  Further, it is preferable that the driving unit is held in a liquid-tight manner from the merging channel, and the driving unit is provided with a stopper for stopping the valve body at a position where the valve body is closest to the wall portion.

  Furthermore, it is preferable that the wall portion is provided above the valve body, and the end portion of the valve body facing the wall portion has an inclined upper end surface that is inclined downward.

  Furthermore, it is preferable that the valve device includes a purge valve disposed in a fuel gas discharge line which is an exhaust gas line for discharging used fuel gas from the fuel cell.

  In the present invention, a gap is formed between the end portion of the valve body and the wall portion at a position where the valve body is closest to the wall portion constituting the merging flow path. Moisture does not stay between the walls. Thereby, it can prevent reliably that the water | moisture content which stayed freezes and a valve body adheres to a wall part. Therefore, the valve device can be configured simply and economically, and freezing is prevented to easily improve startability.

  FIG. 1 is a schematic configuration diagram of a fuel cell system 20 in which a valve device according to a first embodiment of the present invention is incorporated.

  The fuel cell system 20 is mounted on a vehicle such as an automobile, for example, and includes a fuel cell stack 22. In the fuel cell stack 22, a plurality of fuel cells 24 are stacked in the direction of arrow A, and end plates 26a and 26b are disposed at both ends in the stacking direction. It is tightened to.

  The fuel cell 24 includes, for example, an electrolyte membrane / electrode structure 28 in which an anode side electrode 28b and a cathode side electrode 28c are arranged on both sides of a solid polymer electrolyte membrane 28a, and a pair sandwiching the electrolyte membrane / electrode structure 28. Separators 30 and 32. For example, hydrogen gas is supplied to the anode side electrode 28b as a fuel gas, while air containing oxygen, for example, is supplied to the cathode side electrode 28c as an oxidant gas.

  The end plate 26a has a hydrogen supply port 34a for supplying hydrogen gas to the fuel cell 24, and a hydrogen discharge port 34b for discharging the hydrogen gas used for the reaction (power generation) from the fuel cell 24 as exhaust gas. And are provided. The end plate 26b is provided with an air supply port 36a for supplying air to the fuel cell 24 and an air discharge port 36b for discharging the air used for the reaction from the fuel cell 24 as exhaust gas.

  The fuel cell system 20 includes a hydrogen supply passage 38 for supplying a hydrogen-containing gas to the fuel cell stack 22 and a hydrogen discharge passage (fuel gas) that is an exhaust gas line for purging the exhaust gas discharged from the fuel cell stack 22. Discharge line) 40. The hydrogen supply channel 38 is provided with a hydrogen tank 42 for storing high-pressure hydrogen and a regulator 44 for reducing the pressure of hydrogen gas supplied from the hydrogen tank 42.

  A valve device 48 according to the first embodiment is disposed in the hydrogen discharge channel 40. As shown in FIG. 2, the valve device 48 includes a main body portion 52 and a drive portion 54. The main body 52 has an introduction flow path 56 for introducing exhaust gas, a discharge flow path 60 for discharging the exhaust gas to a purge flow path 58 for discarding the exhaust gas, the introduction flow path 56 and the discharge flow path. A merging flow path 62 that merges with 60 is provided. A mesh-like filter 63 is attached to the introduction channel 56.

  The merging channel 62 is provided with an opening / closing mechanism 64 that can freely open and close the merging channel 62. A valve seat 66 is provided in the merging flow path 62, and a valve body 68 that can move forward and backward in the direction of arrow B is seated on the valve seat 66 under the action of the drive unit 54 that constitutes the opening / closing mechanism 64.

  The drive unit 54 includes, for example, a solenoid unit 69, and the shaft 70 moves forward and backward in the axial direction (arrow B direction) under the excitation action of the solenoid unit 69. The shaft 70 is inserted into the core member 71, and a plunger 72 is engaged with the end portion of the shaft 70. A diaphragm (diaphragm member) 74 that partitions the drive unit 54 and the merging flow path 62 in a liquid-tight manner without allowing liquid to pass therethrough is mounted on the shaft 70. The plunger 72 is urged in the direction of arrow B <b> 2 via a spring 75.

  A valve body 68 is attached to the small diameter end portion 70 a of the shaft 70. An annular elastic member 76 is fixed to the lower surface of the valve body 68, and this elastic member 76 is elastically deformed when seated on the valve seat 66 to provide a reliable seal.

  As shown in FIG. 3, on the upstream side of the merging channel 62, the valve body 68 is separated from the valve seat 66 and is closest to the upper wall portion 78 constituting the merging channel 62 (stroke in the direction of arrow B2). A predetermined gap (clearance) H is formed between the end 68 a of the valve body 68 and the upper wall 78. A spring 80 is interposed between the upper portion of the valve body 68 and the upper wall portion 78.

  In order to stop the valve element 68 at the position where the valve element 68 is closest to the upper wall part 78, the drive unit 54 is provided with an insulating stopper 81 made of rubber or the like. The stopper 81 is attached to the upper end surface of the plunger 72.

  A lower wall 82 that forms the downstream side of the merging channel 62 surrounds the diaphragm 74 that is connected to the shaft 70 that is a movable part of the opening / closing mechanism 64, and surrounds the diaphragm 74 and is higher than the height of the diaphragm 74. A low circumferential groove 84 is provided.

  As shown in FIG. 1, the fuel cell system 20 disposes an air supply flow path 90 for supplying air to the fuel cell stack 22 and exhaust gas containing unused air discharged from the fuel cell stack 22 to the outside. And an air discharge channel 92. The air supply channel 90 is provided with a supercharger (or pump) 94 for compressing and supplying air.

  The operation of the fuel cell system 20 configured as described above will be described below in relation to the valve device 48.

  As shown in FIG. 1, the hydrogen gas supplied from the hydrogen tank 42 to the hydrogen supply channel 38 is reduced to a predetermined pressure via the regulator 44 and supplied to the hydrogen supply port 34 a of the fuel cell stack 22. After the hydrogen supplied to the hydrogen supply port 34a moves along the anode side electrode 28b constituting each fuel cell 24, the exhaust gas containing unused hydrogen is discharged from the hydrogen discharge port 34b to the hydrogen discharge channel 40. Is done.

  On the other hand, air is supplied to the air supply channel 90 via the supercharger 94. This air is supplied from the air supply port 36 a to the cathode side electrode 28 c of each fuel cell 24, and exhaust gas containing unused air is discharged from the air discharge port 36 b to the air discharge channel 92. Thereby, in each fuel cell 24, the hydrogen supplied to the anode side electrode 28b and the oxygen in the air supplied to the cathode side electrode 28c react to generate power.

  The exhaust gas discharged into the hydrogen discharge channel 40 is introduced into the introduction channel 56 of the valve device 48. In the valve device 48, as shown in FIG. 2, the solenoid portion 69 is deenergized, the valve body 68 is urged in the direction of the arrow B1, and the elastic member 76 is seated on the valve seat 66. Therefore, the introduction channel 56 and the outlet channel 60 are closed with each other.

  Therefore, when nitrogen or excess water that has entered the hydrogen discharge flow path 40 is discharged (purged) from the hydrogen discharge flow path 40, the drive unit 54 constituting the opening / closing mechanism 64 is energized. That is, as shown in FIG. 3, the shaft 70 is displaced in the direction of the arrow B <b> 2 under the excitation action of the solenoid unit 69. As a result, the valve body 68 attached to the small-diameter end portion 70a of the shaft 70 moves in the arrow B2 direction, and the elastic member 76 is separated from the valve seat 66, while the stopper 81 of the plunger 72 contacts the core member 71. .

  Therefore, the merging channel 62 is opened, and the introduction channel 56 and the outlet channel 60 communicate with each other. For this reason, the exhaust gas introduced into the introduction flow path 56 is discharged from the merge flow path 62 to the purge flow path 58 via the discharge flow path 60, and nitrogen and moisture mixed in the exhaust gas are discarded.

  In this case, in the first embodiment, when the valve body 68 reaches the position closest to the upper wall portion 78, a predetermined gap is provided between the end 68 a of the valve body 68 and the upper wall portion 78. H is formed (see FIG. 3). As a result, moisture does not stay between the end portion 68 a of the valve body 68 and the upper wall portion 78, and the retained water freezes and the valve body 68 is fixed to the upper wall portion 78. This can be reliably prevented.

  Furthermore, the drive unit 54 and the merging channel 62 are liquid-tightly partitioned via a diaphragm 74, and the valve body 68 is located at a position where the valve body 68 is closest to the upper wall portion 78. In order to stop the operation, a stopper 81 is provided. Therefore, there is no portion where the movable portion and the fixed portion are in contact with each other in the merge channel 62, and it is possible to prevent the movable portion and the fixed portion from freezing as much as possible.

  Thereby, in 1st Embodiment, the freezing in the movable part of the opening-and-closing mechanism 64 can be prevented reliably, and the startability can be easily improved with a simple and economical configuration. Is obtained.

  FIG. 4 is a cross-sectional view of the valve device 100 according to the second embodiment of the present invention. The same components as those of the valve device 48 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The confluence channel 62 is provided with an opening / closing mechanism 102, and the opening / closing mechanism 102 includes a valve body 104 seated on the valve seat 66. The upper end portion of the valve body 104 facing the upper wall portion 78 constitutes a substantially conical portion (inclined upper end surface) 106 that is inclined downward.

  In the second embodiment configured as described above, the substantially conical portion 106 is provided at the upper end of the valve body 104, and water can be reliably prevented from staying at the upper end. Therefore, freezing of the valve body 104 can be prevented more reliably, and the valve device 100 can be started smoothly.

  In addition, in 2nd Embodiment, although the substantially cone-shaped part 106 is employ | adopted as an inclination upper end part, it is not limited to this, For example, it sets to the inclination upper part of the cutter shape which inclines only to one side. Also good.

  In the first and second embodiments, the valve devices 48 and 100 are incorporated in the fuel cell system 20, but the present invention is not limited to this.

1 is a schematic configuration diagram of a fuel cell system in which a valve device according to a first embodiment of the present invention is incorporated. It is sectional drawing of the said valve apparatus. It is sectional drawing explaining operation | movement of the said valve apparatus. It is sectional drawing of the valve apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the valve | bulb which concerns on patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Fuel cell system 22 ... Fuel cell stack 24 ... Fuel cell 26a, 26b ... End plate 28 ... Electrolyte membrane and electrode structure 30, 32 ... Separator 34a ... Hydrogen supply port 34b ... Hydrogen discharge port 38 ... Hydrogen supply flow path 40 ... Hydraulic discharge passage 42 ... Hydrogen tank 44 ... Regulator 48, 100 ... Valve device 52 ... Main body 54 ... Driver 56 ... Introduction passage 58 ... Purge passage 60 ... Outlet passage 62 ... Merging passage 64, 102 ... Opening / closing mechanism 66 ... valve seat 68, 104 ... valve body 76 ... elastic member 78 ... upper wall part 81 ... stopper 106 ... substantially conical shape part

Claims (4)

An introduction channel through which gas is introduced;
An outlet channel through which the gas is derived;
A merging channel where the introduction channel and the derivation channel merge;
An opening / closing mechanism that is provided in the merging channel and is capable of opening and closing the merging channel;
With
The opening / closing mechanism includes a valve body that can be advanced and retracted under the action of a drive unit;
A valve seat on which the valve body is seated to close the merging flow path;
And providing
A gap is formed between an end portion of the valve body and the wall portion at a position where the valve body is separated from the valve seat and is closest to a wall portion constituting the merging flow path. Valve device to do. The valve device according to claim 1, wherein the drive unit is liquid-tightly held from the merging channel,
The drive device is provided with a stopper for stopping the valve body at a position where the valve body is closest to the wall portion. The valve device according to claim 1 or 2, wherein the wall portion is provided above the valve body,
An end portion of the valve body facing the wall portion has an inclined upper end surface inclined downward. 4. The valve device according to claim 1, wherein the valve device includes a purge valve disposed in a fuel gas discharge line for discharging used fuel gas from the fuel cell. 5. Valve device to do.

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