JP2011021516A - Ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ejector which improves a gas flow rate controllability in a low flow rate range. <P>SOLUTION: The ejector 50 includes a needle 70, and a nozzle 80 for storing the needle 70 inside for having a hydrogen gas introduced into a first fluid chamber 63 flow in the gap with respect to the needle 70 for ejecting the same from a discharge port 84. The flow rate of the hydrogen gas ejected from the nozzle 80 is adjusted by relatively moving the tip end 71 of the needle 70 and the discharge port 84 of the nozzle 80 based on the pressure of a cathode gas introduced into a third fluid chamber 64. A tapered part 86 tapered toward the discharge port 84 is formed in the nozzle channel 83 of the nozzle 80 for storing the needle 70 and forming the discharge port 84. An O-ring 76 is provided in the tip end 71 of the needle 70. When the tip end 71 of the needle 70 and the discharge port 84 of the nozzle 80 are moved relatively to such a direction that they approach with each other, the O-ring 76 comes in contact with the tapered part 86 for blocking the nozzle channel 83. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ejector. In detail, it is related with the ejector mounted in a fuel cell system.

  In recent years, fuel cell systems have attracted attention as a new power source for automobiles. The fuel cell system includes, for example, a fuel cell that generates power by chemically reacting a reaction gas, a reaction gas supply device that supplies the reaction gas to the fuel cell via a reaction gas flow path, and a control that controls the reaction gas supply device An apparatus.

  The fuel cell has, for example, a stack structure in which several tens to several hundreds of cells are stacked. Here, each cell is configured by sandwiching a membrane electrode structure (MEA) between a pair of separators. The membrane electrode structure includes two electrodes, an anode electrode (cathode) and a cathode electrode (anode), and these electrodes. And a solid polymer electrolyte membrane sandwiched between the two. When such a fuel cell is supplied with hydrogen gas as the anode gas to the anode electrode and supplied with air as the cathode gas to the cathode electrode by the reaction gas supply device, the power is generated by an electrochemical reaction.

  For example, hydrogen gas stored in a hydrogen tank is often used as the hydrogen gas supplied to the fuel cell, but the hydrogen gas supplied from the hydrogen tank has a larger amount of hydrogen than is necessary for power generation. Therefore, the gas discharged from the anode electrode of the fuel cell (hereinafter referred to as “anode off gas”) contains surplus hydrogen that is not used for power generation. Therefore, in the fuel cell system, the anode off gas is recovered using a circulation device, and the recovered anode off gas is merged with the hydrogen gas supplied from the hydrogen tank and supplied to the fuel cell again.

  In the following, such a circulation device will be described by taking as an example a so-called pneumatically driven ejector that does not require an external power source and joins hydrogen gas and anode off-gas using gas pressure energy (patent) Reference 1).

  The ejector disclosed in Patent Document 1 includes a housing, a needle provided inside the housing so as to be able to advance and retreat, and a substantially cylindrical nozzle that is provided inside the housing and accommodates the needle. With respect to such an ejector, hydrogen gas from a hydrogen tank is introduced into the nozzle, flows through a gap with a needle inside the nozzle, and is discharged from a discharge port on the tip side of the nozzle. Here, the flow rate and discharge pressure of the hydrogen gas discharged from the discharge port can be adjusted according to the displacement amount of the needle. On the other hand, the anode off gas is introduced in the vicinity of the discharge port outside the nozzle by the negative pressure of the hydrogen gas discharged from the discharge port, and is joined to the discharged hydrogen gas.

  On the other hand, as a mechanism for displacing the needle, an air extreme pressure introduction chamber into which signal pressure is introduced is provided on the proximal end side of the needle, and a fuel extreme pressure introduction chamber is provided adjacent to the air extreme pressure introduction chamber. The anode off gas is introduced into the fuel extreme pressure introduction chamber as a back pressure through a pipe. Further, the air extreme pressure introduction chamber and the inside of the nozzle are separated by a first diaphragm, and the air extreme pressure introduction chamber and the fuel electrode introduction chamber are separated by a second diaphragm.

  According to this ejector, the needle is advanced and retracted inside the nozzle in accordance with the differential pressure between the air extreme pressure introduction chamber and the fuel extreme pressure introduction chamber. In addition, the portion of the tip of the needle that covers the nozzle outlet is formed in a tapered shape, so that the opening area of the outlet changes according to the advancement and retraction of the needle, and the flow rate and discharge pressure of hydrogen gas are changed. Can be adjusted.

JP 2002-227799 A

  By the way, in order to stably supply a necessary amount of hydrogen to the fuel cell, the ejector is required to have a performance capable of stably discharging hydrogen gas from a low flow rate region to a high flow rate region. However, the portion relating to the adjustment of the flow rate of the discharged hydrogen gas differs between the high flow rate region and the low flow rate region. In other words, the flow rate of hydrogen gas in the high flow rate region is adjusted at the tapered portion of the needle as described above, whereas the flow rate of hydrogen gas in the low flow rate region is the flow rate of hydrogen gas in the needle. It is adjusted at the part that closes the road. Therefore, in order to improve the hydrogen gas flow rate controllability particularly in the low flow rate region, it is necessary to examine in detail the structure for closing the hydrogen gas flow path, but Patent Document 1 does not describe the closing structure.

  The present invention has been made in view of the above-described problems, and improves the gas flow rate controllability in a low flow rate region in an ejector that adjusts the flow rate of gas discharged from the nozzle by advancing and retracting the needle inside the nozzle. An object is to provide an ejector that can be used.

  In order to achieve the above object, the invention described in claim 1 includes a first fluid chamber (for example, first fluid chamber 63 to be described later) into which a first gas (for example, hydrogen gas to be described later) is introduced, a needle (for example, , A needle 70 described later, and the needle accommodated therein, and the first gas introduced into the first fluid chamber is circulated in a gap between the needle and a discharge port (for example, a discharge port 84 described later). And a second fluid chamber (for example, a second fluid to be described later) that is provided on the tip side of the nozzle and into which a second gas (for example, an anode off gas to be described later) is introduced. A diffuser (for example, a later-described diffuser 93) that sucks the second gas introduced into the second fluid chamber by the negative pressure of the first gas discharged from the nozzle and joins the first gas. , Third gas (e.g. A third fluid chamber (for example, a third fluid chamber 64 described later) into which air is introduced, and the tip of the needle is based on the pressure of the third gas introduced into the third fluid chamber. An ejector (for example, an ejector 50 described later) that adjusts the flow rate of the first gas discharged from the nozzle is provided by relatively moving the side and the discharge port of the nozzle. A nozzle channel (for example, a nozzle channel 83 described later) of the nozzle that accommodates the needle and forms the discharge port has a tapered portion (for example, a taper shape described later) that decreases in diameter toward the discharge port. Part 86) is formed, and a seal member (for example, an O-ring 76 described later) is provided on the distal end side of the needle. Further, when the tip end side of the needle and the discharge port of the nozzle are relatively moved in a direction approaching each other, the seal member comes into contact with the tapered portion and blocks the nozzle flow path.

  According to the present invention, the first side discharged from the nozzle outlet by moving the tip side of the needle and the outlet of the nozzle relative to each other based on the pressure of the third gas introduced into the third fluid chamber. Adjust the gas flow rate. Further, a taper-shaped portion that is reduced in diameter toward the discharge port is provided in the nozzle flow path, and a seal member is provided on the tip end side of the needle accommodated in the nozzle flow path. When blocking the flow of the first gas discharged from the discharge port, that is, when closing the nozzle flow path, the needle tip side and the nozzle discharge port are moved relative to each other in a direction approaching each other, Close contact with the taper-shaped portion.

  By the way, when the nozzle flow path is closed using a seal member having a very large diameter with respect to the diameter of the discharge port to which the flow rate of the first gas is adjusted, the difference between the diameter of the discharge port and the diameter of the seal member is caused. As a result, when closing the nozzle flow path, the flow rate of the first gas discharged from the discharge port may change abruptly. On the other hand, in the present invention, the diameter of the seal member is reduced by tightening with a seal member provided on the tip end side of the needle in the tapered portion in the vicinity of the discharge port in the nozzle flow path for accommodating the needle. It can be made close to the diameter. For this reason, according to the present invention, the flow rate of the first gas in the low flow rate region near the cutoff of the nozzle flow path can be changed gently, and the discharge pressure can be continuously changed. The flow controllability of the first gas can be improved. Moreover, since the nozzle channel can be closed with a smaller force by making the diameter of the seal member close to the diameter of the discharge port, the cut-off property can be improved.

  According to a second aspect of the present invention, in the ejector according to the first aspect, the third fluid chamber is provided on a proximal end side of the nozzle, and the first fluid chamber is connected to the second fluid chamber and the second fluid chamber. The first fluid chamber and the second fluid chamber are partitioned by a first diaphragm (for example, a first diaphragm 65 described later), and the first fluid chamber and the third fluid chamber are separated from each other. The fluid chamber is partitioned by a second diaphragm (for example, a second diaphragm 66 described later). The ejector is introduced into the second fluid chamber by moving the tip end side of the needle and the discharge port of the nozzle in a direction away from each other by the pressure of the third gas introduced into the third fluid chamber. The tip end side of the needle and the discharge port of the nozzle are relatively moved in a direction approaching each other by the pressure of the second gas.

  According to the present invention, the first fluid chamber and the second fluid chamber are partitioned by the first diaphragm, and the first fluid chamber and the third fluid chamber are partitioned by the second diaphragm. Then, the needle and the nozzle are relatively moved in a direction away from each other by the pressure of the third gas, and the needle and the nozzle are relatively moved in a direction to approach each other by the pressure of the second gas.

  Thereby, when the pressure of the first gas fluctuates, the fluctuation of the pressure is transmitted to the second fluid chamber and the third fluid chamber via the diaphragms formed on both sides of the first fluid chamber. Therefore, the second gas introduced into the second fluid chamber and the third gas introduced into the third fluid chamber are affected by pressure fluctuations, but the second gas and the third gas are needles. Since the direction in which the nozzle and the nozzle are moved relative to each other is reversed, the influence of this pressure fluctuation is offset. Therefore, the force for relatively moving the nozzle and the needle depends only on the differential pressure between the second fluid chamber and the third fluid chamber. Therefore, the flow rate of gas delivered from the ejector can be made constant. As a result, a regulator for controlling the pressure of the first gas introduced into the first fluid chamber becomes unnecessary.

  According to a third aspect of the present invention, in the ejector according to the second aspect, the third fluid chamber is provided on a proximal end side of the nozzle, and is provided between the first fluid chamber and the third fluid chamber. Is provided with a fourth fluid chamber (for example, a later-described fourth fluid chamber 101A) communicating with the atmosphere, and the first fluid chamber and the second fluid chamber have a first diaphragm (for example, a later-described first diaphragm). 65A), and the first fluid chamber and the fourth fluid chamber are partitioned by a second diaphragm (for example, a second diaphragm 66A described later) having an effective area substantially equal to the first diaphragm, The third fluid chamber and the fourth fluid chamber are partitioned by a third diaphragm (for example, a third diaphragm 102A described later) having an effective area different from that of the first diaphragm and the second diaphragm, and the third fluid chamber The tip of the needle and the discharge port of the nozzle are moved relative to each other in a direction away from each other by the pressure of the introduced third gas, and the needle is pressed by the pressure of the second gas introduced into the second fluid chamber. The tip side of the nozzle and the discharge port of the nozzle are relatively moved in a direction approaching each other.

  According to the present invention, the fourth fluid chamber communicating with the atmosphere is provided between the first fluid chamber and the third fluid chamber. Then, the first fluid chamber and the second fluid chamber are partitioned by the first diaphragm, the first fluid chamber and the fourth fluid chamber are partitioned by the second diaphragm, and the third fluid chamber and the fourth fluid chamber are separated from each other. Is partitioned by a third diaphragm. Then, the needle and the nozzle are relatively moved in a direction away from each other by the pressure of the third gas, and the needle and the nozzle are relatively moved in a direction to approach each other by the pressure of the second gas.

  The effective areas of the first diaphragm and the second diaphragm are made substantially equal, and the effective area of the third diaphragm is made different from the effective areas of the first and second diaphragms. This amplifies or attenuates the pressure of the third gas introduced into the third fluid chamber with a double pressure corresponding to the ratio of the effective area of the third diaphragm and the effective area of the first diaphragm, Can act on two diaphragms. Therefore, with this double pressure, the discharge pressure of the first gas discharged from the nozzle, that is, the pressure of the second fluid chamber can be amplified or attenuated.

  According to a fourth aspect of the present invention, in the ejector according to any one of the first to third aspects, the seal member is an O-ring (for example, an O-ring 76 described later), An annular groove (for example, a groove 75 described later) for holding the O-ring is formed.

  According to the present invention, an O-ring is used as the seal member, and the O-ring is held in an annular groove formed on the outer peripheral surface of the needle. Thereby, compared with the case where a sealing member is baked, for example, it can be set as a small and simple structure, and production cost can be held down.

  According to a fifth aspect of the present invention, in the ejector according to any one of the first to fourth aspects, the ejector reacts an anode gas (for example, hydrogen gas described later) and a cathode gas (for example, air described later). Then, anode gas is supplied to a fuel cell (for example, a fuel cell 10 described later) that generates power. The diffuser outlet (for example, outlet 61 described later) is connected to the fuel cell, and the first fluid chamber has an anode as a first gas from an anode gas supply source (for example, hydrogen tank 22 described later). A gas is introduced, an anode off gas discharged from the fuel cell as a second gas is introduced into the second fluid chamber, and a cathode gas as a third gas is introduced into the third fluid chamber.

  Conventionally, the anode off gas is introduced as a back pressure to the proximal end side of the needle using a pipe. However, since the anode off gas contains moisture generated by the fuel cell, moisture contained in the anode off gas is contained in the pipe. There is a risk that the ejector performance will be reduced. However, according to the present invention, the anode off-gas introduced into the second fluid chamber on the tip end side of the nozzle is not introduced into the base end side of the nozzle, so that the ejector performance is improved even if moisture contained in the anode off-gas is frozen. It can be prevented from lowering.

1 is a block diagram showing a configuration of a fuel cell system to which an ejector according to a first embodiment of the present invention is applied. It is sectional drawing which shows the structure of the ejector which concerns on the said embodiment. It is sectional drawing of the ejector in the state which moved relatively in the direction in which the discharge outlet of the nozzle which concerns on the said embodiment, and the front-end | tip part of a needle are separated most mutually. It is sectional drawing of the ejector in the state which the discharge port of the nozzle which concerns on the said embodiment, and the front-end | tip part of a needle moved relatively in the direction which approaches most mutually. It is sectional drawing which shows the structure of the front-end | tip part of the nozzle which concerns on the said embodiment, and the front-end | tip part of a needle. It is sectional drawing which shows the structure of the front-end | tip part of the nozzle which concerns on the said embodiment, and the front-end | tip part of a needle. It is sectional drawing which shows the structure of the front-end | tip part of the nozzle which concerns on the said embodiment, and the front-end | tip part of a needle. It is sectional drawing which shows the structure of the conventional ejector. It is a figure which shows the relationship between the flow volume of hydrogen gas, and the stroke amount of a nozzle. It is sectional drawing which shows the structure of the ejector which concerns on 2nd Embodiment of this invention. It is a graph which shows the relationship between the pressure of the air supplied to the 3rd fluid chamber which concerns on the said embodiment, and discharge pressure.

  Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a fuel cell system 1 to which an ejector according to a first embodiment of the present invention is applied.
A fuel cell system 1 is mounted on a vehicle and generates a power by reacting a reaction gas, a supply device 20 for supplying hydrogen gas or air (air) to the fuel cell 10, and a control for controlling them. Device 30.

  In such a fuel cell 10, when hydrogen gas as an anode gas is supplied to the anode electrode (cathode) side and air containing oxygen as the cathode gas is supplied to the cathode electrode (anode) side, an electrochemical reaction occurs. Generate electricity.

  The supply device 20 is discharged from the fuel cell 10, an air pump 21 that supplies air to the cathode electrode side of the fuel cell 10, a hydrogen tank 22 and an ejector 50 as anode gas supply sources that supply hydrogen gas to the anode electrode side, and the fuel cell 10. And a diluter 23 for processing the gas.

  The air pump 21 is connected to the cathode electrode side of the fuel cell 10 via an air supply path 41. The air supply path 41 is branched in the middle, and this branched portion becomes an air branch path 411 and is connected to an ejector 50 described later. The air branch path 411 is provided with an orifice 413 and a flow rate adjusting valve 412 for adjusting the flow rate of air flowing through the air branch path 411 in this order from the upstream side to the downstream side. For example, an injector that discharges air in the air branch path 411 is used as the flow rate adjustment valve 412. An air discharge path 42 is connected to the cathode electrode side of the fuel cell 10, and the diluter 23 described above is provided in the middle of the air discharge path 42.

  The hydrogen tank 22 is connected to the anode electrode side of the fuel cell 10 through a hydrogen supply path 43. In the hydrogen supply path 43, a regulator 431, a shut-off valve 432, and an ejector 50 are provided in this order from the upstream side. A hydrogen discharge path 44 is connected to the anode electrode side of the fuel cell 10, and this hydrogen discharge path 44 is connected to the diluter 23. A purge valve 441 is provided in the hydrogen discharge path 44. Further, in the hydrogen discharge path 44, on the fuel cell 10 side of the purge valve 441, the hydrogen discharge path 44 is branched to become a hydrogen recirculation path 45, and this hydrogen recirculation path 45 is connected to the ejector 50 described above. The hydrogen recirculation path 45 is provided with a check valve 451 that prevents the backflow of hydrogen gas. By opening the purge valve 441, the hydrogen gas in the hydrogen discharge path 44 flows into the diluter 23, is diluted with the air in the air discharge path 42, and is discharged.

  Hereinafter, the air flow path constituted by the air supply path 41, the air branch path 411, and the air discharge path 42 is collectively referred to as a cathode system. Further, the hydrogen circulation path constituted by the hydrogen supply path 43, the hydrogen discharge path 44, and the hydrogen reflux path 45 is collectively referred to as an anode system.

  The ejector 50 collects the hydrogen off-gas discharged from the fuel cell 10 to the hydrogen discharge path 44 through the hydrogen reflux path 45 and returns it to the hydrogen supply path 25. Here, the ejector 50 adjusts the flow rate of the hydrogen gas recovered from the hydrogen reflux path 45 based on the pressure of the air introduced from the air branch path 411.

  The control device 30 controls the supply device 20 to generate power in the fuel cell 10. At this time, the control device 30 adjusts the pressure in the anode system by driving the flow rate adjustment valve 412. Specifically, when increasing the pressure in the anode system, the control device 30 drives the flow rate adjustment valve 412 to increase the air pressure introduced into the ejector 50. On the other hand, when the pressure in the anode system is reduced, the flow rate adjustment valve 412 is driven to reduce the air pressure introduced by the ejector 50.

Specifically, the control device 30 generates power in the fuel cell 10 according to the following procedure.
That is, the purge valve 441 is closed and the shut-off valve 432 is opened. Then, by driving the air pump 21, air is supplied to the cathode side of the fuel cell 10 through the air supply path 41. At the same time, hydrogen gas is supplied from the hydrogen tank 22 to the anode side of the fuel cell 10 through the hydrogen supply path 43.

  The hydrogen gas and air supplied to the fuel cell 10 are supplied for power generation, and then flow into the hydrogen discharge path 44 and the air discharge path 42 together with residual water such as produced water on the anode side from the fuel cell 10. Since the purge valve 441 is closed, the hydrogen gas that has flowed to the hydrogen discharge path 44 is returned to the hydrogen supply path 43 through the hydrogen reflux path 45 and reused.

  Here, part of the air supplied from the air pump 21 also flows into the air branch path 411. The pressure in the anode system is adjusted by driving the flow rate adjusting valve 412 and changing the pressure of the air flowing into the ejector 50 through the air branch path 411.

  Thereafter, by opening the purge valve 441 at an appropriate opening degree, the hydrogen gas discharged to the hydrogen discharge passage 44 flows into the diluter 23. The hydrogen gas flowing into the diluter 23 is diluted by the air flowing through the air discharge passage 42 in the diluter 23 and discharged to the outside.

FIG. 2 is a cross-sectional view showing the structure of the ejector 50.
The ejector 50 includes a housing 60, a needle 70 fixed inside the housing 60, and a substantially cylindrical nozzle 80 that accommodates the needle 70.

  The needle 70 is substantially rod-shaped, and a tapered portion 77 is formed at the distal end portion 71 so as to reduce the diameter toward the distal end. An annular groove 75 is formed on the outer peripheral surface of the distal end portion 71 on the base end side with respect to the portion where the tapered portion 77 is formed, and an O-ring 76 as a seal member is fitted into the groove 75. It is disguised.

  In the center of the needle 70, a gas flow path 72 as a through hole extending along the extending direction is formed from the base end surface to the tip end 71. A plurality of through holes are formed in a portion of the needle 70 that communicates with a later-described tapered portion 86 of the nozzle 80 and a portion that communicates with a later-described first fluid chamber 63 of the housing 60. ing.

  In addition, a flange 73 extending perpendicularly to the gas flow path 72 is formed at substantially the center of the needle 70, and a disk-shaped needle support 97 is attached to the flange 73 from the proximal end side. . Further, the needle support portion 97 is fixed to the inner wall surface of the housing 60 together with the needle 70 by a fixing screw 98.

  The nozzle 80 includes a proximal end portion 81 provided on the proximal end side of the needle 70, a distal end portion 82 provided on the distal end side of the needle 70, and a connecting pin 88 that connects the proximal end portion 81 and the distal end portion 82. And comprising. The connecting pin 88 is inserted into the insertion hole 99 formed in the needle support portion 97 together with the collar 89.

A nozzle channel 83 as a through hole extending along the extending direction of the housing 60 is formed at the tip 82 of the nozzle 80. The nozzle flow path 83 accommodates the distal end side of the collar portion 73 of the needle 70, and the distal end surface serves as a discharge port 84. Further, a tapered portion 86 whose diameter decreases toward the discharge port 84 is formed in the vicinity of the discharge port 84 on the distal end side of the nozzle flow channel 83, and a cylindrical portion is formed on the proximal end side of the nozzle flow channel 83. A shaped bearing 85 is provided.
On the other hand, a concave portion 87 is formed in the proximal end portion 81 of the nozzle 80 so as to accommodate the proximal end side with respect to the collar portion 73 of the needle 70.

  The tip side of the needle 70 from the collar 73 is inserted into the nozzle channel 83 of the tip 82 of the nozzle 80 and supported by the bearing 85. On the other hand, the proximal end side of the collar portion 73 of the needle 70 is fitted and supported by the concave portion 87 of the proximal end portion 81 of the nozzle 80. Thereby, the needle 70 is accommodated in the nozzle 80, and the nozzle 80 is held by the needle 70 so as to be able to advance and retreat in the coaxial direction. That is, the tip 71 of the needle 70 and the discharge port 84 of the nozzle 80 can be moved relative to each other.

Further, the movement of the nozzle 80 in the forward direction is restricted by the proximal end portion 81 of the nozzle 80 coming into contact with the needle support portion 97 (see FIG. 3 described later). In this state, the tip 71 of the needle 70 and the discharge port 84 of the nozzle 80 are in the most separated state.
On the other hand, the movement of the nozzle 80 in the backward direction is restricted by the taper-shaped portion 86 of the tip portion 82 of the nozzle 80 coming into contact with the O-ring 76 of the needle 70 (see FIG. 4 described later). In this state, the discharge port 84 of the nozzle 80 and the tip portion 71 of the needle 70 are in the closest state.
In the following description, the amount of displacement in the direction in which the nozzle 80 advances from the state in which the O-ring 76 of the needle 70 is in contact with the tapered portion 86 of the nozzle 80 is referred to as a stroke amount.

  According to the needle 70 and the nozzle 80 described above, the hydrogen gas introduced between the base end portion 81 and the tip end portion 82 of the nozzle 80 enters the gas flow path 72 of the needle 70 provided in the nozzle flow path 83. It is introduced and flows through the gap between the nozzle 70 and the needle 70 and is discharged from the discharge port 84 of the nozzle 80.

  The housing 60 has a substantially cylindrical shape, and a delivery port 61 is formed on the front end surface of the housing 60. The fuel cell 10 is connected to the delivery port 61 via the hydrogen supply path 43.

  The casing 60 is screwed into the base end surface of the casing 60 with two springs 95 and 96 that urge the nozzle 80 to maintain the relative position between the nozzle 80 and the needle 70. , 96 and an adjusting screw 92 for adjusting the urging force. The spring 95 biases the nozzle 80 from the distal end portion 82 side toward the proximal end portion 81 side. On the other hand, the spring 96 urges the nozzle 80 from the proximal end portion 81 side toward the distal end portion 82 side, contrary to the spring 95.

  The space between the outer wall surface of the nozzle 80 and the inner wall surface of the housing 60 is a second fluid chamber 62 located on the tip side of the nozzle 80, a first fluid chamber 63 located on the center side of the nozzle 80, and the nozzle 80. Is divided into three third fluid chambers 64 located on the base end side. That is, the first fluid chamber 63 is provided between the second fluid chamber 62 and the third fluid chamber 64.

  The first fluid chamber 63 and the second fluid chamber 62 are partitioned by a first diaphragm 65. The first diaphragm 65 is formed between the tip portion 82 of the nozzle 80 and the inner wall surface of the housing 60. The first fluid chamber 63 and the third fluid chamber 64 are partitioned by a second diaphragm 66. The second diaphragm 66 is formed between the base end portion 81 of the nozzle 80 and the inner wall surface of the housing 60.

  That is, the first fluid chamber 63 is partitioned by the first diaphragm 65 and the second diaphragm 66 and is provided between the proximal end portion 81 and the distal end portion 82 of the nozzle 80. The effective areas of the first diaphragm 65 and the second diaphragm 66 are substantially the same.

  The housing 60 includes a first communication hole 67 that communicates with the first fluid chamber 63, a second communication hole 68 that communicates with the second fluid chamber 62, and a third communication hole 69 that communicates with the third fluid chamber 64. Is formed. The hydrogen tank 22 is connected to the first communication hole 67 through the hydrogen supply path 43, and hydrogen gas as the first gas is introduced from the hydrogen tank 22 into the first fluid chamber 63 through the first communication hole 67. The The hydrogen gas introduced into the first fluid chamber 63 is introduced into the nozzle 80 and discharged from the discharge port 84 of the nozzle 80.

  The hydrogen recirculation path 45 is connected to the second communication hole 68, and the anode off gas as the second gas discharged from the fuel cell 10 is introduced into the second fluid chamber 62 through the second communication hole 68. An air branch path 411 is connected to the third communication hole 69, and air as a third gas is introduced into the third fluid chamber 64 as an air signal pressure through the third communication hole 69.

  The shape of the front end side of the housing 60 is a diffuser 93 and is connected to the discharge port 84 of the nozzle 80. Specifically, the diffuser 93 is formed by abruptly narrowing the inner diameter of the housing 60 toward the delivery port 61 and then gradually expanding. The diffuser 93 increases the flow rate of the hydrogen gas discharged from the discharge port 84 of the nozzle 80 and sends it out from the delivery port 61. The anode introduced into the second fluid chamber 62 by the negative pressure of the delivered hydrogen gas. The off-gas is sucked and merged with the hydrogen gas discharged from the discharge port 84.

Since the third fluid chamber 64 is provided on the proximal end side of the nozzle 80, the needle 70 and the nozzle 80 are respectively brought into the distal end portion 71 and the discharge port 84 by the air signal pressure introduced into the third fluid chamber 64. Are moved relative to each other in a direction away from each other. On the other hand, since the second fluid chamber 62 is provided on the distal end side of the nozzle 80, the needle 70 and the nozzle 80 are discharged from the respective distal end portions 71 by the pressure of the anode off gas introduced into the second fluid chamber 62. The outlets 84 are moved relative to each other in a direction approaching each other. That is, the air signal pressure acting on the third fluid chamber 64 is P _air , the hydrogen gas discharge pressure (pressure in the anode system) acting on the second fluid chamber 62 is P _out, and the first diaphragm 65 and the second diaphragm When the effective area of the diaphragm 66 is S and the urging force by the two springs 95 and 96 for moving the nozzle 80 backward to the third fluid chamber 64 side is F, the following equation is established.
F = (P _air −P _out ) × S

Therefore, if the effective areas of the first diaphragm 65 and the second diaphragm 66 are the same, the differential pressure (P _air −P _out ) between the third fluid chamber 64 and the second fluid chamber 62 is caused by the springs 95 and 96. It is defined only by the urging force F. On the other hand, the urging force F by the springs 95 and 96 changes according to the stroke amount of the nozzle 80, that is, the relative position between the nozzle 80 and the needle 70. Therefore, the relative position between the tip 71 of the needle 70 and the discharge port 84 of the nozzle 80 changes according to the pressure difference (P _air −P _out ) between the third fluid chamber 64 and the second fluid chamber 62, As a result, as described in detail later, the flow rate and discharge pressure of the hydrogen gas discharged from the discharge port 84 are adjusted.

Next, the operation of the ejector 50 configured as described above will be described with reference to FIGS. 3 and 4.
3 and 4 are cross-sectional views for explaining the operation of the ejector 50. More specifically, FIG. 3 is a cross-sectional view of the ejector 50 in a state in which the discharge port 84 of the nozzle 80 and the distal end portion 71 of the needle 70 are relatively moved in a direction away from each other. FIG. 4 is a cross-sectional view of the ejector 50 in a state in which the discharge port 84 of the nozzle 80 and the distal end portion 71 of the needle 70 are relatively moved in a direction approaching each other.

  If the air signal pressure introduced into the third fluid chamber 64 is higher than a predetermined value, here, the pressure of the anode off-gas introduced into the second fluid chamber 62, the nozzle 80 advances as shown in FIG. The hydrogen gas introduced into the first fluid chamber 63 is introduced into the gas flow path 72 of the needle 70 provided in the nozzle flow path 83, and the gap between the O-ring 76 and the tapered portion 86 of the nozzle 80, In addition, the liquid is discharged from the nozzle 80 through the gap between the tapered portion 77 of the needle 70 and the discharge port 84. The hydrogen gas discharged from the nozzle 80 is sent out from the delivery port 61 with the flow velocity increased by the diffuser 93. The anode off gas introduced into the second fluid chamber 62 is sucked by the negative pressure generated by sending the hydrogen gas in this way, and merges with the hydrogen gas discharged from the discharge port 84.

  Here, when the air signal pressure introduced into the third fluid chamber 64 is increased, the nozzle 80 further advances. And the clearance gap between the discharge port 84 of the nozzle 80 and the taper-shaped part 77 of the needle 70, ie, the opening area of the discharge port 84, becomes large. As a result, the flow rate of hydrogen gas discharged from the nozzle 80 increases, and the pressure in the anode system increases. On the other hand, when the air signal pressure introduced into the third fluid chamber 64 is reduced, the opening area of the discharge port 84 is reduced. As a result, the flow rate of hydrogen gas discharged from the nozzle 80 decreases, and the pressure in the anode system decreases.

  When the air signal pressure introduced into the third fluid chamber 64 is equal to or lower than a predetermined value, here, the pressure of the anode off gas introduced into the second fluid chamber 62, the nozzle 80 moves backward as shown in FIG. . Then, as shown in FIG. 4, the O-ring 76 of the needle 70 is in contact with the tapered portion 86 of the nozzle channel 83 and blocks the nozzle channel 83. Thereby, the flow rate of the hydrogen gas discharged from the nozzle 80 becomes zero.

Next, changes in the flow of hydrogen gas in the nozzle flow path 83 when the stroke amount of the nozzle 80 is changed will be described with reference to FIGS.
5 to 7 are cross-sectional views showing the structures of the tip portion 82 of the nozzle 80 and the tip portion 71 of the needle 70, respectively. More specifically, FIG. 5 is a cross-sectional view when the stroke amount is minimum, and FIG. 7 is a cross-sectional view when the stroke amount is maximum. FIG. 6 is a cross-sectional view when the stroke amount is intermediate between those shown in FIGS.

  As described above, the flow rate of the hydrogen gas discharged from the nozzle 80 is adjusted according to the stroke amount of the nozzle 80. More specifically, in the two portions where the gap between the O-ring 76 and the tapered portion 86 of the nozzle 80 and the gap between the tapered portion 77 and the discharge port 84 of the needle 70 are different, By restricting the flow of hydrogen gas, the flow rate of hydrogen gas discharged from the nozzle 80 is controlled.

  First, in the state shown in FIG. 5, the O-ring 76 is in contact with the tapered portion 86 of the nozzle 80, the nozzle channel 83 is blocked, and the flow rate of hydrogen gas discharged from the nozzle 80 becomes zero. When the stroke amount is increased from the state in which the nozzle flow path 83 is blocked, a gap is formed between the O-ring 76 and the tapered portion 86 of the nozzle 80, whereby hydrogen gas begins to be discharged from the nozzle 80. Here, when the stroke amount is small, since the clearance on the O-ring 76 side is smaller than the clearance on the tapered portion 77 side of the needle 70, the flow rate of the hydrogen gas discharged from the nozzle 80 is on the O-ring 76 side. It is controlled according to the size of the gap.

  When the stroke amount is increased from the state shown in FIG. 5 to the state shown in FIG. 6, the gap on the O-ring 76 side becomes larger than the gap on the discharge port 84 side. For this reason, the portion that controls the flow rate of the hydrogen gas discharged from the nozzle 80 shifts from the O-ring 76 side to the tapered portion 77 side. From the state shown in FIG. 6 to the maximum stroke amount shown in FIG. 7, the flow rate of the hydrogen gas discharged from the nozzle 80 is controlled according to the size of the gap on the tapered portion 77 side. The Rukoto.

Next, regarding the flow rate controllability of hydrogen gas, the ejector 50 of the present embodiment and a conventional ejector will be compared with reference to FIGS. 8 and 9.
FIG. 8 is a cross-sectional view showing the structure of a conventional ejector 150.
As described above, in the ejector 50 of the present embodiment, the nozzle flow path 83 through which hydrogen gas flows is closed by the O-ring 76 provided at the tip 71 of the needle 70. On the other hand, in the conventional ejector 150, a disc-like valve 173 provided on the proximal end side of the needle 170 with respect to the bearing 185 is provided, and a portion of the tip portion 182 of the nozzle 180 facing the valve 173 is provided. An annular rubber seal 178 is provided. That is, the conventional ejector 150 has a structure in which when the nozzle 180 moves backward, the valve 173 comes into contact with the rubber seal 178 to block the hydrogen gas flow path.

  As shown in FIG. 8, in the ejector 150 having a structure in which hydrogen gas is circulated in the gap with the needle 170 in the nozzle flow path 183, a valve 173 that shuts off the hydrogen gas flow path is provided on the base end side from the bearing 185. Then, the diameter of the valve 173 must be larger than the diameter of the bearing 185. For this reason, the diameter of the valve 173 is much larger than the diameter of the discharge port 184.

  FIG. 9 is a diagram showing the relationship between the flow rate of hydrogen gas and the stroke amount of the nozzle. In FIG. 9, the broken line indicates the relationship in the conventional ejector 150, and the solid line indicates the relationship in the ejector 50 of the present embodiment.

  As shown in FIG. 9, when the diameter of the valve 173 that shuts off the hydrogen gas flow path is larger than the diameter of the discharge port 184, in the region where the flow rate is controlled in the portion on the valve 173 side, The flow rate of hydrogen gas changes greatly with a slight change in stroke amount. For this reason, when the portion that controls the flow rate of hydrogen gas shifts from the valve 173 side to the tapered portion 177 side of the needle 170, the rate of change of the hydrogen gas flow rate with respect to the stroke amount changes abruptly.

  On the other hand, in this embodiment, the change in the flow rate of the hydrogen gas with respect to the change in the stroke amount is compared with the conventional case by closing the hydrogen gas flow path with the O-ring 76 having a diameter close to the discharge port 84. Can be small. For this reason, when the portion that controls the flow rate of the hydrogen gas is shifted from the O-ring 76 side to the tapered portion 77 side, the change in the rate of change of the hydrogen gas flow rate relative to the stroke amount can be made smooth. Compared with the prior art, the flow rate controllability of hydrogen gas in a low flow rate region can be improved. Moreover, since it cuts off by a small area compared with the past, it can cut down with a smaller force, As a result, a cut-off property can also be improved.

According to this embodiment, there are the following effects.
(1) Based on the air signal pressure introduced into the third fluid chamber 64, the distal end portion 71 of the needle 70 and the discharge port 84 of the nozzle 80 are moved relative to each other, thereby being discharged from the discharge port 84 of the nozzle 80. Adjust the hydrogen gas flow rate. Further, a tapered portion 86 having a diameter reduced toward the discharge port 84 is provided in the nozzle channel 83, and an O-ring 76 is provided at the tip 71 of the needle 70 accommodated in the nozzle channel 83. When the flow of hydrogen gas discharged from the discharge port 84 is interrupted, that is, when the nozzle flow path 83 is shut off, the distal end portion 71 of the needle 70 and the discharge port 84 of the nozzle 80 are relatively moved in a direction approaching each other. Then, the O-ring 76 and the tapered portion 86 are brought into close contact with each other.

  Further, the diameter of the O-ring 76 is reduced by tightening with the O-ring 76 provided at the distal end portion 71 of the needle 70 in the tapered portion 86 in the vicinity of the discharge port 84 in the nozzle flow path 83 that accommodates the needle 70. The diameter can be close to the diameter of the discharge port 84. For this reason, the flow rate of hydrogen gas in the low flow rate region near the cutoff of the nozzle flow path 83 can be gently changed and the discharge pressure can be continuously changed. Can be improved. Further, by making the diameter of the O-ring 76 close to the diameter of the discharge port 84, the nozzle channel 83 can be shut off with a smaller force.

  (2) The first fluid chamber 63 and the second fluid chamber 62 are partitioned by the first diaphragm 65, and the first fluid chamber 63 and the third fluid chamber 64 are partitioned by the second diaphragm 66. Then, the needle 70 and the nozzle 80 are relatively moved in a direction approaching each other by the air pressure from the air branch passage 411, and the needle 70 and the nozzle 80 are separated from each other by the pressure of the anode off-gas from the hydrogen reflux passage 45. Relative movement in the direction.

  Thereby, when the pressure of the hydrogen gas from the hydrogen tank 22 fluctuates, the fluctuation of the pressure is caused by the second fluid chamber 62 and the third fluid via the diaphragms 65 and 66 formed on both sides of the first fluid chamber 63. It is transmitted to chamber 64. Therefore, the anode off gas from the hydrogen reflux path 45 introduced into the second fluid chamber 62 and the air from the air branch path 411 introduced into the third fluid chamber 64 are affected by pressure fluctuations. In the anode off-gas from the hydrogen recirculation path 45 and the air from the air branch path 411, the directions in which the needle 70 and the nozzle 80 are moved relative to each other are reversed, so the influence of this pressure fluctuation is offset. Therefore, the force that relatively moves the nozzle 80 and the needle 70 depends only on the differential pressure between the second fluid chamber 62 and the third fluid chamber 64. Therefore, the flow rate of gas delivered from the ejector 50 can be made constant. As a result, a regulator for controlling the pressure of the hydrogen gas introduced into the first fluid chamber 63 becomes unnecessary.

  (3) The O-ring 76 was held in an annular groove 75 formed on the outer peripheral surface of the tip portion 71 of the needle 70. Thereby, compared with the case where a sealing member is baked, for example, it can be set as a small and simple structure, and production cost can be held down.

  (4) Since the anode off-gas introduced into the second fluid chamber 62 is not introduced into the base end side of the nozzle 80, it is possible to prevent the performance of the ejector 50 from deteriorating even when moisture contained in the anode off-gas is frozen.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS. 10 and 11.
In the following description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  FIG. 10 is a cross-sectional view showing the structure of an ejector 50A according to the second embodiment of the present invention. The ejector 50A of the present embodiment is different from the first embodiment in the configuration of the housing 60A and the nozzle 80A.

  The space between the outer wall surface of the nozzle 80A and the inner wall surface of the housing 60A is a second fluid chamber 62 located on the tip side of the nozzle 80A, a first fluid chamber 63A located on the center side of the nozzle 80A, and the nozzle 80A. The third fluid chamber 64A located on the base end side, and the fourth fluid chamber 101A provided between the first fluid chamber 63A and the third fluid chamber 64A are partitioned into three.

The first fluid chamber 63A and the second fluid chamber 62 are partitioned by a first diaphragm 65A. The first diaphragm 65 is formed between the tip portion 82 of the nozzle 80A and the inner wall surface of the housing 60A. The first fluid chamber 63 and the fourth fluid chamber 101A are partitioned by a second diaphragm 66A. The second diaphragm 66A is formed between the base end portion 81A of the nozzle 80A and the inner wall surface of the housing 60A. The third fluid chamber 64A and the fourth fluid chamber 101A are partitioned by a third diaphragm 102A. The third diaphragm 102A is formed closer to the base end side than the second diaphragm 66A between the base end portion 81A of the nozzle 80A and the inner wall surface of the housing 60A.
That is, the first fluid chamber 63A is partitioned by the first diaphragm 65A and the second diaphragm 66A, and is provided between the proximal end portion 81A and the distal end portion 82 of the nozzle 80A. The effective areas of the first diaphragm 65A and the second diaphragm 66A are substantially the same, and the effective area of the third diaphragm 102A is different from the effective areas of the first diaphragm 65A and the second diaphragm 66A.

  The housing 60A includes a first communication hole 67 that communicates with the first fluid chamber 63A, a second communication hole 68 that communicates with the second fluid chamber 62, a third communication hole 69 that communicates with the third fluid chamber 64A, A fourth communication hole 103A communicating with the fourth fluid chamber 101A is formed. The fourth fluid chamber 101A communicates with the atmosphere through the fourth communication hole 103A.

  Since the third fluid chamber 64A is provided on the proximal end side of the nozzle 80A, the needle 70 and the nozzle 80A are respectively brought into the distal end portion 71 and the discharge port 84 by the air signal pressure introduced into the third fluid chamber 64A. Are moved relative to each other in a direction away from each other. On the other hand, since the second fluid chamber 62 is provided on the distal end side of the nozzle 80A, the needle 70 and the nozzle 80A are separated from the respective distal end portions 71 by the pressure of the anode off-gas introduced into the second fluid chamber 62A. The outlets 84 are moved relative to each other in a direction approaching each other.

The air signal pressure acting on the third fluid chamber 64A is P _air, and the hydrogen gas discharge pressure (pressure in the anode system) acting on the second fluid chamber 62 is P _out . Further, the effective area of the first diaphragm 65A and the second diaphragm 66A and _{S h,} when the effective area of the third diaphragm 102A and _{S a,} and the gauge pressure _{P Air_gauge} air signal pressure acting on the third fluid chamber 64A, The relational expression shown below is established between the gauge pressure P _{out_gauge} of the discharge pressure of the hydrogen gas acting on the second fluid chamber 62.
P _out — _gauge = P _air — _gauge × (S _a / S _h )

That is, in the ejector 50A of the present embodiment, by first, the effective area of the second diaphragm 65A, the effective area _{S h} and the third diaphragm 102A of 66A would be different and _{S a,} the ratio _{(S a} / S _h ), the air signal pressure P _{air_gauge} can be amplified or attenuated and _acted on the first and second diaphragms 65A and 66A. As a result, the discharge pressure P _{out_gauge} , that is, the second fluid The pressure in the chamber 62 can be amplified or attenuated.

FIG. 11 is a graph showing the relationship between the pressure P _{air_gauge of the} air supplied to the third fluid chamber 64A and the discharge pressure P _{out_gauge} .
As shown in FIG. 11, by increasing the area ratio _(S a / S _h) than 1, as compared with the case where the area ratio _(S a / S _h) and 1, to amplify the discharge pressure _{P Out_gauge} It becomes possible. As described above, in this embodiment, the discharge pressure can be controlled within a region shown by hatching in FIG. 11 by controlling the rotation speed of the air compressor and adjusting the air signal pressure. Conversely, by making the area ratio (S _a / S _h ) smaller than 1, it is possible to attenuate the discharge pressure P _{out_gauge} compared to the case where the area ratio (S _a / S _h ) is 1. It becomes.

  As described above, the ejector 50A according to the present embodiment makes the tip side of the needle 70 and the discharge port 84 of the nozzle 80A relative to each other based on the amplified or attenuated air signal pressure introduced into the third fluid chamber 64A. While moving, the flow rate of the hydrogen gas discharged from the nozzle 80A is adjusted. Therefore, the same effects as (1), (3), and (4) of the first embodiment can be obtained.

It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.
For example, in the above embodiment, the plurality of diaphragms 65 and 66 and the springs 95 and 96 are used to move the nozzle 80 and the needle 70 relative to each other according to the air pressure. However, the present invention is not limited to this. . For example, an electromagnetic drive source such as a motor or a solenoid may be used, and the nozzle and the needle may be moved relative to each other according to the air pressure.

10 Fuel Cell 22 Hydrogen Tank (Anode Gas Supply Source)
50, 50A Ejector 60, 60A Housing 62 Second fluid chamber 63, 63A First fluid chamber 64, 64A Third fluid chamber 65, 65A First diaphragm 66, 66A Second diaphragm 70 Needle 71 Tip 75 Groove 76 O-ring 80 Nozzles 83 Nozzle channels 84 Discharge ports 86 Tapered portions 93 Diffusers 101A Fourth fluid chambers 102A Third diaphragms 103A Fourth communication holes

Claims (5)

A first fluid chamber into which a first gas is introduced;
Needle,
A nozzle that houses the needle therein, circulates the first gas introduced into the first fluid chamber through a gap with the needle, and discharges it from the discharge port;
A second fluid chamber provided on the tip side of the nozzle and into which the second gas is introduced;
A diffuser for sucking the second gas introduced into the second fluid chamber by the negative pressure of the first gas discharged from the nozzle and joining the first gas;
A third fluid chamber into which a third gas is introduced,
Based on the pressure of the third gas introduced into the third fluid chamber, the flow rate of the first gas discharged from the nozzle is adjusted by relatively moving the tip side of the needle and the discharge port of the nozzle. An ejector that
The nozzle flow path of the nozzle that accommodates the needle and forms the discharge port is formed with a tapered portion that is reduced in diameter toward the discharge port,
A seal member is provided on the tip side of the needle,
The ejector according to claim 1, wherein when the tip end side of the needle and the discharge port of the nozzle are relatively moved toward each other, the seal member is in contact with the tapered portion and blocks the nozzle flow path. The third fluid chamber is provided on the proximal end side of the nozzle,
The first fluid chamber is provided between the second fluid chamber and the third fluid chamber,
The first fluid chamber and the second fluid chamber are partitioned by a first diaphragm,
The first fluid chamber and the third fluid chamber are separated by a second diaphragm,
The second gas introduced into the second fluid chamber by moving the tip end side of the needle and the discharge port of the nozzle relative to each other in a direction away from each other by the pressure of the third gas introduced into the third fluid chamber. The ejector according to claim 1, wherein the tip end side of the needle and the discharge port of the nozzle are relatively moved in a direction approaching each other by the pressure of the nozzle. The third fluid chamber is provided on the proximal end side of the nozzle,
A fourth fluid chamber communicating with the atmosphere is provided between the first fluid chamber and the third fluid chamber,
The first fluid chamber and the second fluid chamber are partitioned by a first diaphragm,
The first fluid chamber and the fourth fluid chamber are partitioned by a second diaphragm having an effective area substantially equal to the first diaphragm,
The third fluid chamber and the fourth fluid chamber are partitioned by a third diaphragm having an effective area different from that of the first diaphragm and the second diaphragm,
The second gas introduced into the second fluid chamber by moving the tip end side of the needle and the discharge port of the nozzle relative to each other in a direction away from each other by the pressure of the third gas introduced into the third fluid chamber. The ejector according to claim 1, wherein the tip end side of the needle and the discharge port of the nozzle are relatively moved in a direction approaching each other by the pressure of the nozzle. The sealing member is an O-ring;
The ejector according to any one of claims 1 to 3, wherein an annular groove for holding the O-ring is formed on an outer peripheral surface of the needle. An ejector for supplying anode gas to a fuel cell that generates electricity by reacting anode gas and cathode gas,
The ejector is the ejector according to any one of claims 1 to 4,
The outlet of the diffuser is connected to the fuel cell,
An anode gas is introduced into the first fluid chamber as a first gas from an anode gas supply source,
An anode off gas discharged from the fuel cell as a second gas is introduced into the second fluid chamber,
An ejector, wherein a cathode gas as a third gas is introduced into the third fluid chamber.

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